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Bruner CD, Mahmoud AM, Roberts CJ. Eccentric Pathology in Keratoconus Exhibits Stiffer Biomechanical Response than Central Pathology. OPHTHALMOLOGY SCIENCE 2025; 5:100682. [PMID: 40165909 PMCID: PMC11957518 DOI: 10.1016/j.xops.2024.100682] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/24/2024] [Revised: 11/29/2024] [Accepted: 12/13/2024] [Indexed: 04/02/2025]
Abstract
Purpose To investigate the difference in biomechanical response metrics between central and eccentric pathology and compare axial vs. tangential curvature, as well as zonal vs. single-point values. Design Prospective, observational, cross-sectional study. Participants The study included 67 eyes of 41 subjects diagnosed with keratoconus (KCN). Methods Pentacam tomography and Corvis ST examinations were acquired, and disease severity was defined by maximum curvature, comparing single point of maximum anterior axial curvature (Kmax) vs. magnitude of surrounding 2 mm zonal value (ZKmax) on axial maps, vs. magnitude of steepest 2 mm zone on axial (CSpot_Axi) and tangential (CSpot_Tan) maps located by Cone Location and Magnitude Index (CLMI). Distance between the corneal center and Kmax (Kmax_dist) was compared to radial distance with CLMI (CRad_Axi and CRad_Tan). Single-point Kmax, ZKmax, and CLMI-derived zones were compared with biomechanical metrics via regression analyses, including stiffness parameter at first applanation (SP-A1), deformation amplitude ratio at 2 mm (DA Ratio), integrated inverse radius (IIR), and stress-strain index (SSI). Measurements were analyzed using paired t tests, with t tests between central and eccentric disease, and a significance threshold, P < 0.05. Main Outcome Measures Maximum curvature using axial vs. tangential curvature, zonal vs. single-point curvature, and corneal stiffness metrics compared with cone location. Results Significantly greater central pathology was found using tangential (58 central and 9 eccentric) vs. axial curvature (28 central and 39 eccentric). ZKmax was significantly different than CSpot_Axi and CSpot_Tan (P < 0.0001). CRad_Axi (1.53 ± 0.41 mm) was significantly greater (P < 0.001) than Kmax_dist (1.33 ± 0.56 mm) and CRad_Tan (0.99 ± 0.34 mm). Kmax (56.09 ± 8.99 diopter [D]) was significantly greater than ZKmax (51.81 ± 7.50 D). Regressions for ZKmax, CSpot_Axi, and CSpot_Tan were significantly negative to SP-A1, stiffness parameter at highest concavity, and SSI, whereas significantly positive to DA Ratio and IIR. Regressions for Kmax_dist, CRad_Axi, and CRad_Tan had significantly positive relationships to SSI and significantly negative relationships to DA Ratio and IIR. Conclusions Central pathology has greater frequency with tangential than axial curvature. Corneal stiffness increases as the distance of the cone from the center increases, consistent with the focal nature of KCN. Central stiffness decreases as cone curvature (disease severity) increases. Recommendation is to use zonal values with tangential curvature to evaluate the location of the greatest curvature and changes in curvature over time. Financial Disclosures Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.
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Affiliation(s)
- Cameron D. Bruner
- Ophthalmology & Visual Sciences, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, Ohio
| | - Ashraf M. Mahmoud
- Ophthalmology & Visual Sciences, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, Ohio
- Biomedical Engineering, College of Engineering, The Ohio State University, Columbus, Ohio
| | - Cynthia J. Roberts
- Ophthalmology & Visual Sciences, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, Ohio
- Biomedical Engineering, College of Engineering, The Ohio State University, Columbus, Ohio
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2
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Vought R, Greenstein SA, Gelles J, Hersh PS. The Pathophysiology of Keratoconus. Cornea 2025; 44:137-143. [PMID: 38830186 DOI: 10.1097/ico.0000000000003585] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Accepted: 04/29/2024] [Indexed: 06/05/2024]
Abstract
PURPOSE Keratoconus is a progressive disease characterized by changes in corneal shape, resulting in loss of visual function. There remains a lack of comprehensive understanding regarding its underlying pathophysiology. This review aims to bridge this gap by exploring structural failures and inflammatory processes involved in the etiology and progression of keratoconus. METHODS A literature review was conducted using PubMed and Google Scholar databases, screening for articles published in English using the keyword combinations of "keratoconus" with "pathophysiology," "pathology," "metabolism," "inflammatory," "oxidative stress," "cytokines," "enzymes," "collagen," and "cornea." Articles published between January 1, 1970, and June 1, 2023, were queried and reviewed, with greater emphasis placed on more recent data. Fifty-six relevant studies were examined to develop a thorough review of the pathophysiological mechanisms at play in keratoconus. RESULTS Biomechanical structural failures in the cornea seem to be the primary militating factors in keratoconus etiology and progression. These include disruptions in the arrangement in the collagen lamellae, a decrease in collagen levels, a decrease in natural collagen crosslinking, and changes in lysosomal enzyme activity. Immunologic changes have also been identified in keratoconus, challenging the traditional view of the condition as noninflammatory. Elevated levels of proinflammatory cytokines like IL-1b, IL-6, IL-17, and TNF-α have been observed, along with increased apoptosis of keratocytes. Increased oxidative stress leads to the activation of collagenase and gelatinase enzymes. CONCLUSIONS Keratoconus is a complex condition influenced by both structural defects and inflammatory processes. Understanding these mechanisms can inform clinical management and potentially lead to more effective treatments.
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Affiliation(s)
- Rita Vought
- Institute of Ophthalmology and Visual Science, Rutgers New Jersey Medical School, Newark, NJ; and
| | - Steven A Greenstein
- Institute of Ophthalmology and Visual Science, Rutgers New Jersey Medical School, Newark, NJ; and
- Cornea and Laser Eye Institute, CLEI Center for Keratoconus, Teaneck, NJ
| | - John Gelles
- Institute of Ophthalmology and Visual Science, Rutgers New Jersey Medical School, Newark, NJ; and
- Cornea and Laser Eye Institute, CLEI Center for Keratoconus, Teaneck, NJ
| | - Peter S Hersh
- Institute of Ophthalmology and Visual Science, Rutgers New Jersey Medical School, Newark, NJ; and
- Cornea and Laser Eye Institute, CLEI Center for Keratoconus, Teaneck, NJ
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Moon L, Kaur P, Wang J, Sodhi A, Eberhart C, Soiberman U. Mechanical Strain of Corneal Epithelium Influences the Expression of Genes Implicated in Keratoconus. Invest Ophthalmol Vis Sci 2025; 66:52. [PMID: 39847367 PMCID: PMC11758933 DOI: 10.1167/iovs.66.1.52] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2024] [Accepted: 12/18/2024] [Indexed: 01/24/2025] Open
Abstract
Purpose Although mechanical injury to the cornea (e.g. chronic eye rubbing) is a known risk factor for keratoconus progression, how it contributes to loss of corneal integrity is not known. Here, we set out to determine how eye rubbing can influence keratoconus progression by exploring the expression of known disease markers in mechanically stressed corneal epithelial cells. Methods To explore the effects of mechanical stress on the expression of genes implicated in keratoconus (e.g. WNT10A, COL12A1, and TGFB1), we measured their expression using an in vitro model that simulates eye rubbing by cyclic stretching of an immortalized human corneal epithelial cell line (hTCEpi) for 16 hours. We further examined the influence of WNT10A expression in hTCEpi cells using loss-of-function approaches. Results Mechanical strain led to a marked reduction in WNT10A mRNA and protein expression, as well as decreased collagen XII mRNA and protein expression, in hTCEpi cells. Reduced expression of WNT10A protein in WNT10A knockdown cells resulted in reduced protein expression of collagens I and XII, and reduced mRNA expression of MMP9 and TGFB1. Conversely, primary keratocytes treated with recombinant WNT10A protein increased TGFB1 mRNA expression. Conclusions We provide a molecular explanation for how mechanical strain results in reduced expression of WNT10A in the corneal epithelium, which, in turn, leads to depletion of collagen type I and XII, and TGFβ1 expression. These results provide a molecular link among mechanical strain, WNT10A expression, and the biomechanical failure of the keratoconus cornea.
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Affiliation(s)
- Loren Moon
- Wilmer Eye Institute, Johns Hopkins Medical Institute, Baltimore, Maryland, United States
| | - Pritpal Kaur
- Wilmer Eye Institute, Johns Hopkins Medical Institute, Baltimore, Maryland, United States
| | - Jiangxia Wang
- Department of Biostatistics, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland, United States
| | - Akrit Sodhi
- Wilmer Eye Institute, Johns Hopkins Medical Institute, Baltimore, Maryland, United States
| | - Charles Eberhart
- Wilmer Eye Institute, Johns Hopkins Medical Institute, Baltimore, Maryland, United States
| | - Uri Soiberman
- Wilmer Eye Institute, Johns Hopkins Medical Institute, Baltimore, Maryland, United States
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4
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Rigi M, Son HS, Moon L, Matthaei M, Srikumaran D, Jun AS, Eberhart CG, Soiberman US. Collagen type XII is undetectable in keratoconus Bowman's layer. Br J Ophthalmol 2024; 108:343-348. [PMID: 36746614 PMCID: PMC10466210 DOI: 10.1136/bjo-2022-322180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Accepted: 01/21/2023] [Indexed: 02/08/2023]
Abstract
PURPOSE Corneal biomechanical failure is the hallmark of keratoconus (KC); however, the cause of this failure remains elusive. Collagen type XII (COL12A1), which localises to Bowman's layer (BL), is thought to function in stress-bearing areas, such as BL. Given the putative protective role of COL12A1 in biomechanical stability, this study aims to characterise COL12A1 expression in all corneal layers involved in KC. METHODS TaqMan quantitative PCR was performed on 31 corneal epithelium samples of progressive KC and myopic control eyes. Tissue microarrays were constructed using full-thickness corneas from 61 KC cases during keratoplasty and 18 non-KC autopsy eyes and stained with an antibody specific to COL12A1. Additionally, COL12A1 was knocked out in vitro in immortalised HEK293 cells. RESULTS COL12A1 expression was reduced at transcript levels in KC epithelium compared with controls (ratio: 0.58, p<0.03). Immunohistochemical studies demonstrated that COL12A1 protein expression in BL was undetectable, with reduced expression in KC epithelium, basement membrane and stroma. CONCLUSIONS The apparent absence of COL12A1 in KC BL, together with the functional importance that COL12A1 is thought to have in stress bearing areas, suggests that COL12A1 may play a role in the pathogenesis of KC. Further studies are necessary to investigate the mechanisms that lead to COL12A1 dysregulation in KC.
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Affiliation(s)
- Mohammed Rigi
- Wilmer Eye Institute, Johns Hopkins Medical Institutions, Baltimore, Maryland, USA
| | - Hyeck-Soo Son
- Wilmer Eye Institute, Johns Hopkins Medical Institutions, Baltimore, Maryland, USA
- Department of Ophthalmology, University Hospital Heidelberg, Heidelberg, Germany
| | - Loren Moon
- Wilmer Eye Institute, Johns Hopkins Medical Institutions, Baltimore, Maryland, USA
| | - Mario Matthaei
- Department of Ophthalmology, University Hospital Cologne, Cologne, Germany
| | - Divya Srikumaran
- Wilmer Eye Institute, Johns Hopkins Medical Institutions, Baltimore, Maryland, USA
| | - Albert S Jun
- Wilmer Eye Institute, Johns Hopkins Medical Institutions, Baltimore, Maryland, USA
| | - Charles G Eberhart
- Wilmer Eye Institute, Johns Hopkins Medical Institutions, Baltimore, Maryland, USA
| | - Uri S Soiberman
- Wilmer Eye Institute, Johns Hopkins Medical Institutions, Baltimore, Maryland, USA
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Gcabashe N, Moodley VR, Hansraj R. Keratoconus management at public sector facilities in KwaZulu-Natal, South Africa: Practitioner perspectives. AFRICAN VISION AND EYE HEALTH 2022. [DOI: 10.4102/aveh.v81i1.698] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
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D'Souza S, Nair AP, Sahu GR, Vaidya T, Shetty R, Khamar P, Mullick R, Gupta S, Dickman MM, Nuijts RMMA, Mohan RR, Ghosh A, Sethu S. Keratoconus patients exhibit a distinct ocular surface immune cell and inflammatory profile. Sci Rep 2021; 11:20891. [PMID: 34686755 PMCID: PMC8536707 DOI: 10.1038/s41598-021-99805-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Accepted: 09/23/2021] [Indexed: 02/06/2023] Open
Abstract
Inflammatory factors have been considered to contribute to keratoconus (KC) pathogenesis. This study aims to determine the immune cells subsets and soluble inflammatory factor profile on the ocular surface of KC patients. 32 KC subjects (51 eyes) across different grades of severity and 15 healthy controls (23 eyes) were included in the study. Keratometry and pachymetry measurements were recorded. Ocular surface immune cells (collected by ocular surface wash) immunophenotyped using flow cytometry include leukocytes, neutrophils, macrophages, natural killer (NK) cells, pan-T cells, gamma delta T (γδT) cells and NKT cells. Tear fluid collected using Schirmer's strip was used to measure 50 soluble factors by multiplex ELISA. Proportions of activated neutrophils, NK cells and γδT cells were significantly increased in KC patients. Significantly higher levels of tear fluid IL-1β, IL-6, LIF, IL-17A, TNFα, IFNα/β/γ, EPO, TGFβ1, PDGF-BB, sVCAM, sL-selectin, granzyme-B, perforin, MMP2, sFasL and IgE, along with significantly lower levels of IL-1α and IL-9 were observed in KC patients. Alterations observed in few of the immuno-inflammatory parameters correlated with grades of disease, allergy, eye rubbing and keratometry or pachymetry measurements. The observation implies a distinct immuno-inflammatory component in KC pathogenesis and its potential as an additional therapeutic target in KC management.
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Affiliation(s)
- Sharon D'Souza
- Department of Cornea and Refractive Surgery, Narayana Nethralaya, Bangalore, India
| | - Archana Padmanabhan Nair
- GROW Research Laboratory, Narayana Nethralaya Foundation, 3rd Floor, Narayana Nethralaya, #258/A Hosur Road, Bommasandra, Bangalore, 560099, India.,Manipal Academy of Higher Education, Manipal, India
| | - Ganesh Ram Sahu
- GROW Research Laboratory, Narayana Nethralaya Foundation, 3rd Floor, Narayana Nethralaya, #258/A Hosur Road, Bommasandra, Bangalore, 560099, India
| | - Tanuja Vaidya
- GROW Research Laboratory, Narayana Nethralaya Foundation, 3rd Floor, Narayana Nethralaya, #258/A Hosur Road, Bommasandra, Bangalore, 560099, India.,Manipal Academy of Higher Education, Manipal, India
| | - Rohit Shetty
- Department of Cornea and Refractive Surgery, Narayana Nethralaya, Bangalore, India
| | - Pooja Khamar
- Department of Cornea and Refractive Surgery, Narayana Nethralaya, Bangalore, India
| | - Ritika Mullick
- Department of Cornea and Refractive Surgery, Narayana Nethralaya, Bangalore, India
| | - Sneha Gupta
- Department of Cornea and Refractive Surgery, Narayana Nethralaya, Bangalore, India
| | - Mor M Dickman
- University Eye Clinic Maastricht, Maastricht University Medical Center, Maastricht, The Netherlands.,MERLN Institute for Technology-Inspired Regenerative Medicine, Maastricht University, Maastricht, The Netherlands
| | - Rudy M M A Nuijts
- University Eye Clinic Maastricht, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Rajiv R Mohan
- Department of Veterinary Medicine and Surgery, University of Missouri, 1600 E. Rollins Rd, Columbia, MO, 65211, USA. .,Mason Eye Institute, School of Medicine, University of Missouri, Columbia, MO, USA. .,Harry S Truman Veterans' Memorial Hospital, Columbia, MO, USA.
| | - Arkasubhra Ghosh
- GROW Research Laboratory, Narayana Nethralaya Foundation, 3rd Floor, Narayana Nethralaya, #258/A Hosur Road, Bommasandra, Bangalore, 560099, India. .,Singapore Eye Research Institute, Singapore, Singapore.
| | - Swaminathan Sethu
- GROW Research Laboratory, Narayana Nethralaya Foundation, 3rd Floor, Narayana Nethralaya, #258/A Hosur Road, Bommasandra, Bangalore, 560099, India.
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7
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Sufi AR, Soundaram M, Gohil N, Keenan JD, Prajna NV. Structural Changes in Thin Keratoconic Corneas Following Crosslinking with Hypotonic Riboflavin: Findings on In Vivo Confocal Microscopy. J Ophthalmic Vis Res 2021; 16:325-337. [PMID: 34394861 PMCID: PMC8358763 DOI: 10.18502/jovr.v16i3.9429] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Accepted: 04/29/2021] [Indexed: 11/24/2022] Open
Abstract
Purpose To report structural changes observable in in vivo confocal microscopy (IVCM) in keratoconic corneas < 400 μm treated with hypotonic riboflavin and collagen crosslinking (CXL). Methods Ten eyes of ten patients with progressive keratoconus and corneal thickness between 350 and 399 μm underwent CXL with hypotonic riboflavin. IVCM was performed preoperatively and at one month, three months, and six months after the procedure. Results IVCM analysis one month postoperatively showed complete absence of the subepithelial nerve plexus with gradual regeneration over six months in 8 of the 10 eyes, and poor regeneration in the remaining 2 eyes. The anterior stroma showed extracellular lacunae and hyper-reflective cytoplasm in a honeycomb appearance signifying edema at one month which gradually decreased over six months post CXL. Stromal keratocyte apoptosis was evident in the anterior stroma in all cases and extended to the posterior stroma in four eyes with gradual regeneration evident at three and six months. The specular endothelial count decreased by 8% (P = 0.005) post-CXL, but no corneas developed clinical signs of endothelial trauma. Conclusion IVCM analysis of thin corneas after hypotonic CXL showed posterior corneal structural changes. Posterior stromal changes were accompanied by a decrease in the endothelial cell count. This case series was a preliminary feasibility study that might necessitate conducting a well-designed controlled study.
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Affiliation(s)
- Aalia Rasool Sufi
- Department of Cornea and Refractive Surgery, Aravind Eye Hospital, Madurai, India
| | - M Soundaram
- Department of Cornea and Refractive Surgery, Aravind Eye Hospital, Madurai, India
| | - Nilam Gohil
- Department of Cornea and Refractive Surgery, Aravind Eye Hospital, Madurai, India
| | - Jeremy D Keenan
- Francis I. Proctor Foundation, University of California, San Francisco.,Department of Ophthalmology, University of California, San Francisco, California, USA
| | - N Venkatesh Prajna
- Department of Cornea and Refractive Surgery, Aravind Eye Hospital, Madurai, India
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Measurement of In Vivo Biomechanical Changes Attributable to Epithelial Removal in Keratoconus Using a Noncontact Tonometer. Cornea 2021; 39:946-951. [PMID: 32355111 DOI: 10.1097/ico.0000000000002344] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
PURPOSE To compare the biomechanical properties of the cornea after epithelial removal in eyes with keratoconus undergoing corneal cross-linking. METHODS Prospective interventional case series at a university hospital tertiary referral center. Corneal biomechanical properties were measured in patients with keratoconus undergoing corneal cross-linking, immediately before and after epithelial debridement by using a dynamic ultrahigh-speed Scheimpflug camera equipped with a noncontact tonometer. RESULTS The study comprised 45 eyes of 45 patients with a mean age of 19.6 ± 4.9 years (range 14-34). The cornea was found to be 23.7 ± 15.7 μm thinner after epithelial removal (P < 0.01). Corneal stiffness was reduced after epithelial removal as demonstrated by a significant decrease of parameters such as stiffness parameter A1 (12.31, P < 0.01), stiffness parameter-highest concavity (2.25, P < 0.01), A1 length (0.13 mm, P = 0.04), highest concavity radius of curvature (0.26 mm, P = 0.01), highest concavity time (0.22 ms, P = 0.04) and an increase in A1 velocity (-0.01 m/s, P = 0.01), A1 deformation amplitude (-0.03 mm, P ≤ 0.01), A1 deflection length (-0.32 mm, P < 0.01), A2 deformation amplitude (-0.03 mm, P = 0.01), and A2 deflection length (-1.00 mm, P < 0.01). There were no significant differences in biomechanical intraocular pressure (0.15 mm Hg, P = 0.78), deformation amplitude (0.03, P = 0.54), maximum inverse radius (-0.01 mm, P = 0.57), and whole eye movement length (-0.02 mm, P = 0.12). CONCLUSIONS Dynamic ultrahigh-speed Scheimpflug camera equipped with a noncontact tonometer offers an alternative method for in vivo measurements of the epithelial layer's contribution to corneal biomechanical properties. Our results suggest that corneal epithelium may play a more significant role in corneal biomechanical properties in patients with keratoconus than previously described.
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Cheung IM, Mcghee CN, Sherwin T. A new perspective on the pathobiology of keratoconus: interplay of stromal wound healing and reactive species‐associated processes. Clin Exp Optom 2021; 96:188-96. [DOI: 10.1111/cxo.12025] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2012] [Accepted: 10/30/2012] [Indexed: 12/13/2022] Open
Affiliation(s)
- Isabella My Cheung
- Department of Ophthalmology, New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand,
| | - Charles Nj Mcghee
- Department of Ophthalmology, New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand,
| | - Trevor Sherwin
- Department of Ophthalmology, New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand,
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Shetty R, D'Souza S, Khamar P, Ghosh A, Nuijts RMMA, Sethu S. Biochemical Markers and Alterations in Keratoconus. Asia Pac J Ophthalmol (Phila) 2020; 9:533-540. [PMID: 33323707 DOI: 10.1097/apo.0000000000000332] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Keratoconus (KC) is a corneal ectatic condition characterized by focal structural changes, resulting in progressive thinning, biomechanical weakening, and steeping of the cornea that can lead to worsening visual acuity due to irregular astigmatism and corneal scarring in more advanced cases. It is a relatively common ectatic disease of the cornea predominantly affecting the younger population. Despite its worldwide prevalence, its incidence is rather varied with a higher incidence among the Middle Eastern and South Asian population. Dysregulated corneal extracellular matrix remodeling underlies KC pathogenesis. However, a lack of absolute clarity regarding the factors that initiate and drive progression poses a significant challenge in its prevention and management. KC is a complex multifactorial disease as it is associated with a wide variety of etiological factors such as environmental stimuli/insults, oxidative stress, genetic predisposition, comorbidities, and eye rubbing. A series of studies using corneal tissues (epithelium, stroma), cultured corneal fibroblasts/keratocytes, tear fluid, aqueous humor, and blood from KC subjects has reported significant alterations in various biochemical factors such as extracellular matrix components, cellular homeostasis regulators, inflammatory factors, hormones, metabolic products, and chemical elements. It has become apparent that alterations in the biochemical mediators (related to various etiologies) could contribute to KC pathogenesis by altering the dynamics of extracellular matrix remodeling events such as collagen deposition, degradation, and cross-linking in the cornea. Determining key disease contributing biochemical mediators would aid in disease monitoring, prediction or abatement of disease progression, and development of targeted therapeutics to improve disease prognosis.
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Affiliation(s)
- Rohit Shetty
- Department of Cornea and Refractive Surgery, Narayana Nethralaya, Bangalore, India
| | - Sharon D'Souza
- Department of Cornea and Refractive Surgery, Narayana Nethralaya, Bangalore, India
| | - Pooja Khamar
- Department of Cornea and Refractive Surgery, Narayana Nethralaya, Bangalore, India
| | - Arkasubhra Ghosh
- GROW Research Lab, Narayana Nethralaya Foundation, Bangalore, India
| | - Rudy M M A Nuijts
- University Eye Clinic Maastricht, Maastricht University Medical Center, Maastricht, the Netherlands
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Pjano MA, Biscevic A, Grisevic S, Gabric I, Salkica AS, Ziga N. Pachymetry and Elevation Back Map Changes in Keratoconus Patients After Crosslinking Procedure. Med Arch 2020; 74:105-108. [PMID: 32577050 PMCID: PMC7296420 DOI: 10.5455/medarh.2020.74.105-108] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Introduction: The crosslinking (CXL) procedure using the standard Dresden protocol is established as the gold standard for the treatment of progressive keratoconus. Aim: The aim of this paper is to correlate the pachymetry and elevation back map (EBM) changes in the period from 3 to12 months of keratoconus patients after the CXL procedure. M Methods: Forty-four eyes of 34 patients with keratoconus were analyzed after performed standard Dresden protocol CXL procedure. All of them underwent complete preoperative examination with a follow up of 12 months with a focus on pachymetry and EBM changes performed by Oculus Pentacam (Scheimpflug technology) analysis. Results: Pachymetry changed significantly in 12 months post cross-linking, especially in the first 6 months after which it slightly increased. Differences in EBM preoperatively and 12 months postoperatively were not statistically significant. Conclusion: Corneal pachymetry in keratoconus patients decreases after the CXL procedure. Differences in pachymetry preoperatively and 3, 6 and 12 months postoperatively were statistically significant, but the value of corneal thickness increased from the third month to 12 months post-op. Differences in EBM preoperatively and 12 months postoperatively were not still statistically significant, which is good, because the increase in elevation, as one of the signs of progression of the keratoconus - did not occur.
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Affiliation(s)
| | - Alma Biscevic
- Eye Clinic "Svjetlost", Sarajevo, Bosnia and Herzegovina.,University Eye Hospital "Svjetlost" Zagreb, School of Medicine University of Rijeka, Croatia
| | - Senad Grisevic
- Eye Clinic "Svjetlost", Sarajevo, Bosnia and Herzegovina
| | - Ivan Gabric
- University Eye Hospital "Svjetlost" Zagreb, School of Medicine University of Rijeka, Croatia
| | | | - Nina Ziga
- Eye Clinic "Svjetlost", Sarajevo, Bosnia and Herzegovina
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Wadhwa H, Ismail S, McGhee JJ, Van der Werf B, Sherwin T. Sphere-forming corneal cells repopulate dystrophic keratoconic stroma: Implications for potential therapy. World J Stem Cells 2020; 12:35-54. [PMID: 32110274 PMCID: PMC7031758 DOI: 10.4252/wjsc.v12.i1.35] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 09/11/2019] [Accepted: 11/13/2019] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Keratoconus is a degenerative corneal disease characterised by aberrant cell behaviour and loss of matrix that can result in vision loss. Cells extracted from peripheral corneas can form stem cell-enriched spheres, which have shown the potential to repopulate the normal peripheral corneal stroma in vitro upon sphere implantation but have not been previously studied in keratoconic tissue. AIM To investigate the therapeutic potential of stem cell-enriched spheres formed from extracted peripheral human corneal cells when introduced to keratoconic tissue. METHODS Stem cell-enriched spheres were formed from extracts of normal cadaveric human peripheral corneal cells. These spheres were implanted into incisions created in full thickness and onto the surface of 10 µm thin sections of keratoconic and normal stromal tissues in vitro. Tissue sections were used to maximise use of limited keratoconic tissue available for research. Living cells were stained with Calcein-AM and visualised with stereo and fluorescence microscopy to assess survival and behaviours between the time of implantation day 0 and 14 d (D14) from implantation. Sphere cells in implanted tissues were characterised for stem cell and differentiation markers using immunohistochemistry and droplet digital PCR to assess the potential implications of these characteristics in the use of spheres in keratoconus treatment. RESULTS Spheres were successfully implanted into full-thickness central corneal tissue and onto the surface of 10 µm thin en face tissue sections. No observable differences were seen in sphere migration, proliferation or differentiation in keratoconic tissue compared to normal between day 0 and D14. Spheres stained positively with Calcein-AM up to D14. Cell migration increased from day 0 to D14, occurring radially in three dimensions from the sphere and in alignment with tissue edges. Cell proliferation marker, EdU, was detected at day 10. Implanted spheres stained positively for putative stem cell markers ∆Np63α and ABCB5, while ABCG2, ABCB5, ∆Np63 and p63α were detectable by droplet digital PCR up to D14. Double immunolabelling revealed absence of ABCB5 staining in migrated cells but positive staining of alpha smooth muscle actin (myofibroblast marker) in some migrated cells. Droplet digital PCR showed similar expression patterns of differentiation markers but a reduction in stem cell markers between normal and keratoconic tissue with an increase in stromal cell markers and a reduction in epithelial cell markers, indicating an appropriate response to repopulating diseased tissue. CONCLUSION Cells from implanted stem cell-enriched spheres can repopulate a keratoconic corneal stromal surface in a directed manner and exhibit migratory stromal cell phenotypes.
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Affiliation(s)
- Himanshu Wadhwa
- Department of Ophthalmology, Faculty of Medical and Health Sciences, The University of Auckland, Auckland 1023, New Zealand
| | - Salim Ismail
- Department of Ophthalmology, Faculty of Medical and Health Sciences, The University of Auckland, Auckland 1023, New Zealand
| | - Jennifer J McGhee
- Department of Ophthalmology, Faculty of Medical and Health Sciences, The University of Auckland, Auckland 1023, New Zealand
| | - Bert Van der Werf
- Department of Epidemiology and Biostatistics, School of Population Health, Faculty of Medical and Health Sciences, The University of Auckland, Auckland 1023, New Zealand
| | - Trevor Sherwin
- Department of Ophthalmology, Faculty of Medical and Health Sciences, The University of Auckland, Auckland 1023, New Zealand.
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Shinde V, Hu N, Renuse S, Mahale A, Pandey A, Eberhart C, Stone D, Al-Swailem SA, Maktabi A, Chakravarti S. Mapping Keratoconus Molecular Substrates by Multiplexed High-Resolution Proteomics of Unpooled Corneas. OMICS-A JOURNAL OF INTEGRATIVE BIOLOGY 2019; 23:583-597. [PMID: 31651220 DOI: 10.1089/omi.2019.0143] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Keratoconus (KCN) is a leading cause for cornea grafting worldwide. Keratoconus is a multifactorial disease that causes progressive thinning of the cornea and whose etiology is poorly understood. Several studies have used proteomics on patient tear fluids to identify potential biomarkers. However, proteome of the cornea itself has not been investigated fully. We report here new findings from a case-control study using multiplexed mass spectrometry (MS) on individual (unpooled) corneas to gain deeper insights into proteins and biomarkers relevant to keratoconus. We employed a high-pressure approach to extract total protein from individual corneas from five cases and five controls, followed by trypsin digestion and tandem mass tag (TMT) labeling. The MS-derived data were searched using the Human NCBI RefSeq protein database v92, with peptides and proteins filtered at 1% false discovery rate. A total of 3132 proteins were detected, of which 627 were altered significantly (p ≤ 0.05) in keratoconus corneas. The increases were overwhelmingly in the mTOR/PI3/AKT signal-mediated regulations of cell survival and proliferation, nonsense-mediated decay of transcripts, and proteasomal pathways. The decreases were in several extracellular matrix proteins and in many members of the complement system. Importantly, this multiplexed proteomic study of keratoconus corneas identified, to our knowledge, the largest number of corneal proteins. The novel findings include changes in pathways that regulate transcript stability, proteasomal degradation, and the complement system in corneas with keratoconus. These observations offer new prospects toward future discovery of novel molecular targets for diagnostic and therapeutic innovations for patients with keratoconus.
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Affiliation(s)
- Vishal Shinde
- Department of Ophthalmology, NYU Langone Health, New York, New York
| | - Nan Hu
- Department of Ophthalmology, NYU Langone Health, New York, New York
| | - Santosh Renuse
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota
| | - Alka Mahale
- Research Department, King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia
| | - Akhilesh Pandey
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota
| | - Charles Eberhart
- Pathology, Ophthalmology and Oncology Department, Johns Hopkins Hospital, Baltimore, Maryland
| | - Donald Stone
- Department of Ophthalmology, Johns Hopkins University, Baltimore, Maryland
| | - Samar A Al-Swailem
- Anterior Segment Division, King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia
| | - Azza Maktabi
- Department of Pathology, King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia
| | - Shukti Chakravarti
- Department of Ophthalmology, NYU Langone Health, New York, New York.,Department of Pathology, NYU Langone Health, New York, New York
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Ma J, Wang Y, Wei P, Jhanji V. Biomechanics and structure of the cornea: implications and association with corneal disorders. Surv Ophthalmol 2018; 63:851-861. [PMID: 29857022 DOI: 10.1016/j.survophthal.2018.05.004] [Citation(s) in RCA: 78] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Revised: 05/17/2018] [Accepted: 05/21/2018] [Indexed: 12/14/2022]
Abstract
Recent studies have shown that alterations in corneal biomechanical properties are associated with corneal pathologies, particularly corneal ectasia. Moreover, these alterations may have implications with regard to the outcomes of therapeutic modalities and corneal refractive surgeries. We address corneal anatomy and its relevance to corneal biomechanical characteristics, as well as ocular and systemic conditions associated with changes in corneal biomechanics.
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Affiliation(s)
- Jiaonan Ma
- Clinical College of Ophthalmology, Tianjin Medical University, Tianjin, China
| | - Yan Wang
- Clinical College of Ophthalmology, Tianjin Medical University, Tianjin, China; Tianjin Eye Hospital, Tianjin Eye Institute, Tianjin Key Laboratory of Ophthalmology and Visual Science, Naikai University, Tianjin Medical University, Tianjin, China.
| | - Pinghui Wei
- Tianjin Eye Hospital, Tianjin Eye Institute, Tianjin Key Laboratory of Ophthalmology and Visual Science, Naikai University, Tianjin Medical University, Tianjin, China
| | - Vishal Jhanji
- UPMC Eye Center, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
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Mazzotta C, Traversi C, Baiocchi S, Sergio P, Caporossi T, Caporossi A. Conservative Treatment of Keratoconus by Riboflavin-UVA-Induced Cross-Linking of Corneal Collagen: Qualitative Investigation of Corneal Epithelium and Subepithelial Nerve Plexus Regeneration by in vivo HRT II System Confocal Microscopy in Humans. Eur J Ophthalmol 2018; 16:530-5. [PMID: 16952090 DOI: 10.1177/112067210601600405] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
PURPOSE To assess corneal tissue modifications after riboflavin-UVA-induced cross-linking of corneal collagen in patients with progressive keratoconus as well as regeneration of epithelium and subepithelial nerve plexus by in vivo HRT II system confocal microscopy in humans. METHODS Ten patients with progressive keratoconus were treated by riboflavin-UVA-induced cross-linking of corneal collagen, involving assessment of ultrastructural modifications of the corneal epithelium and subepithelial nerve plexus by HRT II system confocal microscopy. Treatment included instillation of 0.1% riboflavin-20% dextrane solution 5 minutes before UVA irradiation and every 5 minutes for a total of 30 minutes. Radiant energy was 3 mW/cm 2 or 5.4 Joule/cm 2 and the source was dual UVA (370 nm) light-emitting LED. The protocol included the operation followed by antibiotic medication and eye dressing with a soft therapeutic contact lens. Changes in epithelium and subepithelial and stromal nerve plexus were assessed by HRT II system confocal microscopy in vivo. RESULTS After 5 days of soft contact lens wearing, corneal epithelium has a regular morphology and density. Disappearance of subepithelial stromal nerve fibers was observed in the central irradiated area where, 1 month after the operation, initial reinnervation was microscopically observed. No changes in nerve fibers were observed in the peripheral untreated with a clear lateral transition between the two areas. Six months after the operation, the anterior subepithelial stroma was recolonized by nerve fibers with restoration of corneal sensitivity. CONCLUSIONS HRT II system confocal microscopy confirms corneal epithelium restore and re-innervation after riboflavin-UVA-induced collagen cross-linking directly in vivo in humans.
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Affiliation(s)
- C Mazzotta
- Department of Ophthalmological Sciences, Siena University, Viale Bracci 8, 53100 Siena, Italy
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Shetty R, Vunnava KP, Dhamodaran K, Matalia H, Murali S, Jayadev C, Murugeswari P, Ghosh A, Das D. Characterization of Corneal Epithelial Cells in Keratoconus. Transl Vis Sci Technol 2018; 8:2. [PMID: 30627477 PMCID: PMC6322712 DOI: 10.1167/tvst.8.1.2] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Accepted: 11/09/2018] [Indexed: 01/08/2023] Open
Abstract
Purpose We studied the cellular characteristics of epithelial cells in the cone and extraconal periphery of corneas in keratoconus eyes. Methods This prospective observational study was conducted at Narayana Nethralaya Eye Institute. A total of 83 and 42 eyes with keratoconus and normal topography, respectively, were included in the study. Corneal epithelial cells were collected and analyzed for apoptosis, proliferation, epithelial-mesenchymal transition, and differentiation status using molecular and biochemical tools. Statistical analysis was performed using the Student's t-test. Results Corneal epithelial cells from the cone showed significantly higher expression of proapoptotic marker BAX (P < 0.005) compared to controls. Significantly elevated expression of cell cycle markers CYCLIN D1 (P < 0.005) and Ki67 (P < 0.005) were noted in the extraconal region compared to controls. Cells of the cone showed significantly higher ZO-1 (P < 0.005) and lower vimentin (P < 0.005) compared to controls. Significantly lower expression of the differentiation marker CK3/12 (P < 0.05) was observed in cones compared to controls. Conclusions Cones of keratoconic corneas show enhanced cell death, poor differentiation, proliferation and epithelial-mesenchymal transition. The cellular changes of the corneal epithelial cells in the cone and extraconal region differ significantly in a keratoconus corneas. Translational Relevance Characterization of patient-specific corneal epithelial cellular status in keratoconus has the potential to determine the optimal treatment and therapeutic outcomes paving the way towards personalized treatment in the future.
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Affiliation(s)
- Rohit Shetty
- Department of Cornea and Refractive Surgery, Narayana Nethralaya Eye Institute, Bangalore, Karnataka, India
| | - Krishna Poojita Vunnava
- Department of Cornea and Refractive Surgery, Narayana Nethralaya Eye Institute, Bangalore, Karnataka, India
| | - Kamesh Dhamodaran
- Stem Cell Research Laboratory, GROW Laboratory, Narayana Nethralaya Foundation, Bangalore, Karnataka, India.,Current address: Department of Basic Sciences, The Ocular Surface Institute, College of Optometry, University of Houston, Houston, TX, USA
| | - Himanshu Matalia
- Department of Cornea and Refractive Surgery, Narayana Nethralaya Eye Institute, Bangalore, Karnataka, India
| | - Subramani Murali
- Stem Cell Research Laboratory, GROW Laboratory, Narayana Nethralaya Foundation, Bangalore, Karnataka, India
| | - Chaitra Jayadev
- Department of Vitreo-Retinal Services, Narayana Nethralaya Eye Institute, Bangalore, Karnataka, India
| | - Ponnulagu Murugeswari
- Stem Cell Research Laboratory, GROW Laboratory, Narayana Nethralaya Foundation, Bangalore, Karnataka, India
| | - Arkasubhra Ghosh
- GROW Laboratory, Narayana Nethralaya Foundation, Bangalore, Karnataka, India
| | - Debashish Das
- Stem Cell Research Laboratory, GROW Laboratory, Narayana Nethralaya Foundation, Bangalore, Karnataka, India
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Soiberman U, Foster JW, Jun AS, Chakravarti S. Pathophysiology of Keratoconus: What Do We Know Today. Open Ophthalmol J 2017; 11:252-261. [PMID: 28932341 PMCID: PMC5585454 DOI: 10.2174/1874364101711010252] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2017] [Revised: 04/01/2017] [Accepted: 06/14/2017] [Indexed: 12/19/2022] Open
Abstract
Keratoconus is a common corneal ectasia that leads to progressive visual impairment. Numerous studies have shown abnormal protein expression patterns in keratoconic corneas. However, the specific mechanisms causing this disease remain ambiguous. This review aims to provide an update on morphological studies of the keratoconic cornea, relate these early studies with current findings from proteomic, biochemical and cell culture studies and to postulate possible pathogenic pathways.
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Affiliation(s)
- Uri Soiberman
- Cornea Division, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, USA
| | - James W Foster
- Cornea Division, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, USA
| | - Albert S Jun
- Cornea Division, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, USA
| | - Shukti Chakravarti
- Cornea Division, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, USA
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18
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Karimi A, Razaghi R, Navidbakhsh M, Sera T, Kudo S. Computing the influences of different Intraocular Pressures on the human eye components using computational fluid-structure interaction model. Technol Health Care 2017; 25:285-297. [DOI: 10.3233/thc-161280] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- Alireza Karimi
- Department of Mechanical Engineering, Kyushu University, Fukuoka 819-0395, Japan
| | - Reza Razaghi
- Basir Eye Health Research Center, Tehran 14186, Iran
| | - Mahdi Navidbakhsh
- Department of Biomechanics, Science and Research Branch, Islamic Azad University, Tehran 755/4515, Iran
| | - Toshihiro Sera
- Department of Mechanical Engineering, Kyushu University, Fukuoka 819-0395, Japan
| | - Susumu Kudo
- Department of Mechanical Engineering, Kyushu University, Fukuoka 819-0395, Japan
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Molecular and Histopathological Changes Associated with Keratoconus. BIOMED RESEARCH INTERNATIONAL 2017; 2017:7803029. [PMID: 28251158 PMCID: PMC5303843 DOI: 10.1155/2017/7803029] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Revised: 12/16/2016] [Accepted: 01/04/2017] [Indexed: 12/13/2022]
Abstract
Keratoconus (KC) is a corneal thinning disorder that leads to loss of visual acuity through ectasia, opacity, and irregular astigmatism. It is one of the leading indicators for corneal transplantation in the Western countries. KC usually starts at puberty and progresses until the third or fourth decade; however its progression differs among patients. In the keratoconic cornea, all layers except the endothelium have been shown to have histopathological structural changes. Despite numerous studies in the last several decades, the mechanisms of KC development and progression remain unclear. Both genetic and environmental factors may contribute to the pathogenesis of KC. Many previous articles have reviewed the genetic aspects of KC, but in this review we summarize the histopathological features of different layers of cornea and discuss the differentially expressed proteins in the KC-affected cornea. This summary will help emphasize the major molecular defects in KC and identify additional research areas related to KC, potentially opening up possibilities for novel methods of KC prevention and therapeutic intervention.
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Duru N, Haşhaş OE, Göktaş E, Duru Z, Arifoğlu HB, Ulusoy DM, Karatepe Haşhaş AS, Ataş M. Corneal Sublayers Thickness in Patients With Mitral Valve Prolapse. Eye Contact Lens 2016; 44:55-59. [PMID: 27541972 DOI: 10.1097/icl.0000000000000300] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVES The aim of this study was to compare the thickness of each corneal sublayer in patients with mitral valve prolapse (MVP) and healthy individuals. METHODS A total of 38 eyes from 38 patients with MVP and 34 eyes from 34 age- and sex-matched healthy individuals were included in this study. The thickness of the corneal epithelium, Bowman layer, stroma, and Descemet membrane-endothelium complex were measured on the central cornea (i.e., corneal apex) and both the inferior and superior halves of the cornea with anterior segment module of spectral domain optical coherence tomography. RESULTS No statistically significant differences emerged between the study and control groups in terms of Bowman layer thickness in the central cornea and the cornea's superior half (P=0.092 and P=0.128, respectively). However, in the inferior half of the cornea, Bowman layer thickness among patients with MVP was 11.95±2.34 μm (range 7-16 μm) and in the control group was 13.03±1.62 μm (range 10-16 μm), which made for a statistically significant difference (P=0.025). CONCLUSIONS Our study revealed thinning of Bowman layer in the inferior half of the cornea in patients with MVP.
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Affiliation(s)
- Necati Duru
- Department of Ophthalmology (N.D., E.G., Z.D., H.B.A., D.M.U., A.S.K.H., M.A.), Kayseri Education and Research Hospital, Kayseri, Turkey; Department of Cardiovascular Surgery (O.E.H.), Kayseri Education and Research Hospital, Kayseri, Turkey
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Vinciguerra P, Romano V, Rosetta P, Legrottaglie EF, Kubrak-Kisza M, Azzolini C, Vinciguerra R. Iontophoresis-Assisted Corneal Collagen Cross-Linking with Epithelial Debridement: Preliminary Results. BIOMED RESEARCH INTERNATIONAL 2016; 2016:3720517. [PMID: 27547758 PMCID: PMC4980498 DOI: 10.1155/2016/3720517] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/16/2016] [Revised: 05/16/2016] [Accepted: 06/30/2016] [Indexed: 11/29/2022]
Abstract
Purpose. To report the early outcomes of iontophoresis-assisted corneal collagen cross-linking procedure with epithelial debridement (I-SCXL). Methods. Twenty eyes of twenty patients with progressive keratoconus were included in this prospective clinical study. Best spectacle corrected visual acuity (BSCVA), sphere and cylinder refraction, corneal topography, Scheimpflug tomography, aberrometry, anterior segment optical coherence tomography (AS-OCT), and endothelial cell count were assessed at baseline and at 1, 3, and 6 months of follow-up. The parameters considered to establish keratoconus progression were always proven with differential maps as change in curvature in the cone area of at least 1 diopter obtained with an instantaneous map. Results. Functional parameters showed a significant improvement (p < 0.05) of BSCVA after 3 and 6 months of follow-up. Morphological parameters indicated stabilization of the corneal ectasia during the follow-up; however, a positive trend was noted with a mean flattening of 1.73 D. Minimum pachymetry values showed thinning that remained constant after the treatment. The demarcation line was clearly visible in all patients, reaching a depth of 308.2 ± 37.74 μm. None of the patients had continuous progression of keratoconus or had to repeat cross-linking procedures. Endothelial cell counts did not change significantly (p > 0.05). Conclusion. The early results indicate that the I-SCXL may be able to reduce the treatment time and improve the riboflavin diffusion.
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Affiliation(s)
- Paolo Vinciguerra
- Humanitas Clinical and Research Center, Via Manzoni 56, 20089 Rozzano, Italy
- Humanitas University, Rozzano, 20089 Milan, Italy
| | - Vito Romano
- Department of Corneal and External Eye Diseases, St. Paul's Eye Unit, Royal Liverpool University Hospital, Liverpool L7 8XP, UK
| | - Pietro Rosetta
- Humanitas Clinical and Research Center, Via Manzoni 56, 20089 Rozzano, Italy
| | | | - Magdalena Kubrak-Kisza
- Department and Clinic of Ophthalmology, Wrocław Medical University, 50-556 Wrocław, Poland
| | - Claudio Azzolini
- Department of Surgical Sciences, Division of Ophthalmology, University of Insubria, 21100 Varese, Italy
| | - Riccardo Vinciguerra
- Department of Surgical Sciences, Division of Ophthalmology, University of Insubria, 21100 Varese, Italy
- Department of Ophthalmology, Humanitas Mater Domini, Via Gerenzano 2, 21053 Castellanza, Italy
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Oliver VF, Vincent AL. The Genetics and Pathophysiology of IC3D Category 1 Corneal Dystrophies: A Review. Asia Pac J Ophthalmol (Phila) 2016; 5:272-81. [PMID: 27213768 DOI: 10.1097/apo.0000000000000205] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Corneal dystrophies are a group of inherited disorders affecting the cornea, many of which lead to visual impairment. The International Committee for Classification of Corneal Dystrophies has established criteria to clarify the status of the various corneal dystrophies, which include the knowledge of the underlying genetics. In this review, we discuss the International Committee for Classification of Corneal Dystrophies category 1 (second edition) corneal dystrophies, for which a clear genetic link has been established. We highlight the various mechanisms underlying corneal dystrophy pathology, including structural disorganization, instability or maladhesion, aberrant protein stability and deposition, abnormal cellular proliferation or apoptosis, and dysfunction of normal enzymatic processes. Understanding these genetic mechanisms is essential for designing targets for therapeutic intervention, especially in the age of gene therapy and gene editing.
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Affiliation(s)
- Verity Frances Oliver
- From the *Department of Ophthalmology, New Zealand National Eye Centre, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand; and †Eye Department, Greenlane Clinical Centre, Auckland District Health Board, Auckland, New Zealand
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Oliver VF, van Bysterveldt KA, Cadzow M, Steger B, Romano V, Markie D, Hewitt AW, Mackey DA, Willoughby CE, Sherwin T, Crosier PS, McGhee CN, Vincent AL. A COL17A1 Splice-Altering Mutation Is Prevalent in Inherited Recurrent Corneal Erosions. Ophthalmology 2016; 123:709-22. [PMID: 26786512 DOI: 10.1016/j.ophtha.2015.12.008] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Revised: 11/06/2015] [Accepted: 12/05/2015] [Indexed: 12/28/2022] Open
Abstract
PURPOSE Corneal dystrophies are a genetically heterogeneous group of disorders. We previously described a family with an autosomal dominant epithelial recurrent erosion dystrophy (ERED). We aimed to identify the underlying genetic cause of ERED in this family and 3 additional ERED families. We sought to characterize the potential function of the candidate genes using the human and zebrafish cornea. DESIGN Case series study of 4 white families with a similar ERED. An experimental study was performed on human and zebrafish tissue to examine the putative biological function of candidate genes. PARTICIPANTS Four ERED families, including 28 affected and 17 unaffected individuals. METHODS HumanLinkage-12 arrays (Illumina, San Diego, CA) were used to genotype 17 family members. Next-generation exome sequencing was performed on an uncle-niece pair. Segregation of potential causative mutations was confirmed using Sanger sequencing. Protein expression was determined using immunohistochemistry in human and zebrafish cornea. Gene expression in zebrafish was assessed using whole-mount in situ hybridization. Morpholino-induced transient gene knockdown was performed in zebrafish embryos. MAIN OUTCOME MEASURES Linkage microarray, exome analysis, DNA sequence analysis, immunohistochemistry, in situ hybridization, and morpholino-induced genetic knockdown results. RESULTS Linkage microarray analysis identified a candidate region on chromosome chr10:12,576,562-112,763,135, and exploration of exome sequencing data identified 8 putative pathogenic variants in this linkage region. Two variants segregated in 06NZ-TRB1 with ERED: COL17A1 c.3156C→T and DNAJC9 c.334G→A. The COL17A1 c.3156C→T variant segregated in all 4 ERED families. We showed biologically relevant expression of these proteins in human cornea. Both proteins are expressed in the cornea of zebrafish embryos and adults. Zebrafish lacking Col17a1a and Dnajc9 during development show no gross corneal phenotype. CONCLUSIONS The COL17A1 c.3156C→T variant is the likely causative mutation in our recurrent corneal erosion families, and its presence in 4 independent families suggests that it is prevalent in ERED. This same COL17A1 c.3156C→T variant recently was identified in a separate pedigree with ERED. Our study expands the phenotypic spectrum of COL17A1 disease from autosomal recessive epidermolysis bullosa to autosomal dominant ERED and identifies COL17A1 as a key protein in maintaining integrity of the corneal epithelium.
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Affiliation(s)
- Verity F Oliver
- Department of Ophthalmology, New Zealand National Eye Centre, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Katherine A van Bysterveldt
- Department of Ophthalmology, New Zealand National Eye Centre, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Murray Cadzow
- Department of Biochemistry, Dunedin School of Medicine, Otago University, Dunedin, New Zealand
| | - Bernhard Steger
- Department of Corneal and External Eye Diseases, St. Paul's Eye Unit, Royal Liverpool University Hospital, Liverpool, United Kingdom
| | - Vito Romano
- Department of Corneal and External Eye Diseases, St. Paul's Eye Unit, Royal Liverpool University Hospital, Liverpool, United Kingdom
| | - David Markie
- Pathology Department, Dunedin School of Medicine, Otago University, Dunedin, New Zealand
| | - Alex W Hewitt
- Menzies Institute for Medical Research, University of Tasmania, Hobart, Australia; Lions Eye Institute, University of Western Australia, Perth, Australia
| | - David A Mackey
- Menzies Institute for Medical Research, University of Tasmania, Hobart, Australia; Lions Eye Institute, University of Western Australia, Perth, Australia
| | - Colin E Willoughby
- Department of Corneal and External Eye Diseases, St. Paul's Eye Unit, Royal Liverpool University Hospital, Liverpool, United Kingdom; Department of Eye and Vision Science, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, United Kingdom
| | - Trevor Sherwin
- Department of Ophthalmology, New Zealand National Eye Centre, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Philip S Crosier
- Department of Molecular Medicine and Pathology, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Charles N McGhee
- Department of Ophthalmology, New Zealand National Eye Centre, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand; Eye Department, Greenlane Clinical Centre, Auckland District Health Board, Auckland, New Zealand
| | - Andrea L Vincent
- Department of Ophthalmology, New Zealand National Eye Centre, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand; Eye Department, Greenlane Clinical Centre, Auckland District Health Board, Auckland, New Zealand.
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Nasrollahi K, Ghoreishi M, Hanjani S, Ziaie H, Mohammadinia M, Kabiri M, Bahadoran M. Evaluation of the outcomes of corneal collagen cross-linking in progressive keratoconic eyes. Adv Biomed Res 2015; 4:208. [PMID: 26605237 PMCID: PMC4627174 DOI: 10.4103/2277-9175.166145] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Accepted: 06/10/2015] [Indexed: 11/12/2022] Open
Abstract
Background: Corneal collagen cross-linking (CXL) is gaining popularity as a treatment in arresting the progression of keratoconus. It is a relatively new therapy using ultraviolet-A (UVA) with a photosensitizer to increase corneal stiffness. The purpose of this study was to evaluate visual, keratometric and topographic outcomes after corneal CXL in progressive keratoconic eyes. Materials and Methods: In this prospective nonrandomized clinical study, 140 eyes of 110 patients with progressive keratoconus were treated by combined riboflavin/UVA CXL. Mean sphere, mean cylinder uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), manifest refractive spherical equivalent, corneal topography, pachymetry, and endothelial cell morphology were examined preoperatively and 12–24 months postoperatively. Results: The preoperative mean sphere was −3.33 ± 3.13 diopter (D) and decreased to −3.09 ± 3.09 D (P = 0.007). The preoperative mean cylinder was −4.05 ± 2.29 D and changed to −3.79 ± 2.23 D (P = 0.011). UDVA changed from 0.95 ± 0.64 logarithm of the minimum angle of resolution (logMAR) to 0.85 ± 0.59 logMAR (P = 0.003). Thirty-five eyes (25%) gained one or more lines of preoperative UDVA, 87 eyes (62.1%) did not change and 18 eyes (12.8%) lost one or more lines of the preoperative UDVA. CDVA in 80% of the patients remained stable (no lines lost). Statistical analysis of keratometry, pachymetry, and endothelial cell count did not show the significant difference after surgery. Conclusion: Our study showed improvement in visual and refractive results of the corneal CXL and confirmed that CXL is the safe and effective procedure.
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Affiliation(s)
- Kobra Nasrollahi
- Department of Ophthalmology, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Mohammad Ghoreishi
- Department of Ophthalmology, Isfahan University of Medical Sciences, Isfahan, Iran ; Department Research and Development, Parsian Clinic of Ophthalmology, Isfahan, Iran
| | - Shahriar Hanjani
- Department Research and Development, Parsian Clinic of Ophthalmology, Isfahan, Iran
| | - Hamidreza Ziaie
- Department of Ophthalmology, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Mohadeseh Mohammadinia
- Department of Ophthalmology, Isfahan University of Medical Sciences, Isfahan, Iran ; Department Research and Development, Parsian Clinic of Ophthalmology, Isfahan, Iran
| | - Majid Kabiri
- Department of Ophthalmology, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Maryam Bahadoran
- Department Research and Development, Parsian Clinic of Ophthalmology, Isfahan, Iran
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Karamichos D, Zieske JD, Sejersen H, Sarker-Nag A, Asara JM, Hjortdal J. Tear metabolite changes in keratoconus. Exp Eye Res 2015; 132:1-8. [PMID: 25579606 DOI: 10.1016/j.exer.2015.01.007] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Revised: 01/05/2015] [Accepted: 01/07/2015] [Indexed: 11/18/2022]
Abstract
While efforts have been made over the years, the exact cause of keratoconus (KC) remains unknown. The aim of this study was to identify alterations in endogenous metabolites in the tears of KC patients compared with age-matched healthy subjects. Three groups were tested: 1) Age-matched controls with no eye disease (N = 15), 2) KC - patients wearing Rigid Gas permeable lenses (N = 16), and 3) KC - No Correction (N = 14). All samples were processed for metabolomics analysis using LC-MS/MS. We identified a total of 296 different metabolites of which >40 were significantly regulated between groups. Glycolysis and gluconeogenesis had significant changes, such as 3-phosphoglycerate and 1,3 diphosphateglycerate. As a result the citric acid cycle (TCA) was also affected with notable changes in Isocitrate, aconitate, malate, and acetylphosphate, up regulated in Group 2 and/or 3. Urea cycle was also affected, especially in Group 3 where ornithine and aspartate were up-regulated by at least 3 fold. The oxidation state was also severely affected. Groups 2 and 3 were under severe oxidative stress causing multiple metabolites to be regulated when compared to Group 1. Group 2 and 3, both showed significant down regulation in GSH-to-GSSG ratio when compared to Group 1. Another indicator of oxidative stress, the ratio of lactate - pyruvate was also affected with Groups 2 and 3 showing at least a 2-fold up regulation. Overall, our data indicate that levels of metabolites related to urea cycle, TCA cycle and oxidative stress are highly altered in KC patients.
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Affiliation(s)
- D Karamichos
- Ophthalmology, University of Oklahoma - Dean McGee Eye Institute, Oklahoma City, OK, USA.
| | - J D Zieske
- Schepens Eye Research Institute/Massachusetts Eye and Ear and the Department of Ophthalmology Harvard Medical School, 20 Staniiford Street, Boston, MA, USA.
| | - H Sejersen
- Department of Ophthalmology, Aarhus University Hospital, Aarhus C, Denmark.
| | - A Sarker-Nag
- Ophthalmology, University of Oklahoma - Dean McGee Eye Institute, Oklahoma City, OK, USA.
| | - John M Asara
- Division of Signal Transduction/Mass Spectrometry Core, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.
| | - J Hjortdal
- Department of Ophthalmology, Aarhus University Hospital, Aarhus C, Denmark.
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Imaging mass spectrometry by matrix-assisted laser desorption/ionization and stress-strain measurements in iontophoresis transepithelial corneal collagen cross-linking. BIOMED RESEARCH INTERNATIONAL 2014; 2014:404587. [PMID: 25276786 PMCID: PMC4167647 DOI: 10.1155/2014/404587] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Accepted: 08/14/2014] [Indexed: 11/18/2022]
Abstract
PURPOSE To compare biomechanical effect, riboflavin penetration and distribution in transepithelial corneal collagen cross-linking with iontophoresis (I-CXL), with standard cross linking (S-CXL) and current transepithelial protocol (TE-CXL). MATERIALS AND METHODS The study was divided into two different sections, considering, respectively, rabbit and human cadaver corneas. In both sections corneas were divided according to imbibition protocols and irradiation power. Imaging mass spectrometry by matrix-assisted laser desorption/ionization (MALDI-IMS) and stress-strain measurements were used. Forty-eight rabbit and twelve human cadaver corneas were evaluated. RESULTS MALDI-IMS showed a deep riboflavin penetration throughout the corneal layers with I-CXL, with a roughly lower concentration in the deepest layers when compared to S-CXL, whereas with TE-CXL penetration was considerably less. In rabbits, there was a significant increase (by 71.9% and P = 0.05) in corneal rigidity after I-CXL, when compared to controls. In humans, corneal rigidity increase was not significantly different among the subgroups. CONCLUSIONS In rabbits, I-CXL induced a significant increase in corneal stiffness as well as better riboflavin penetration when compared to controls and TE-CXL but not to S-CXL. Stress-strain in human corneas did not show significant differences among techniques, possibly because of the small sample size of groups. In conclusion, I-CXL could be a valid alternative to S-CXL for riboflavin delivery in CXL, preserving the epithelium.
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Impaired corneal biomechanical properties and the prevalence of keratoconus in mitral valve prolapse. J Ophthalmol 2014; 2014:402193. [PMID: 24864193 PMCID: PMC4016888 DOI: 10.1155/2014/402193] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2014] [Revised: 03/26/2014] [Accepted: 03/31/2014] [Indexed: 11/18/2022] Open
Abstract
Objective. To investigate the biomechanical characteristics of the cornea in patients with mitral valve prolapse (MVP) and the prevalence of keratoconus (KC) in MVP. Materials and Methods. Fifty-two patients with MVP, 39 patients with KC, and 45 control individuals were recruited in this study. All the participants underwent ophthalmologic examination, corneal analysis with the Sirius system (CSO), and the corneal biomechanical evaluation with Reichert ocular response analyzer (ORA). Results. KC was found in six eyes of four patients (5.7%) and suspect KC in eight eyes of five patients (7.7%) in the MVP group. KC was found in one eye of one patient (1.1%) in the control group (P = 0.035). A significant difference occurred in the mean CH and CRF between the MVP and control groups (P = 0.006 and P = 0.009, resp.). All corneal biomechanical and topographical parameters except IOPcc were significantly different between the KC-MVP groups (P < 0.05). Conclusions. KC prevalence is higher than control individuals in MVP patients and the biomechanical properties of the cornea are altered in patients with MVP. These findings should be considered when the MVP patients are evaluated before refractive surgery.
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Kankariya VP, Kymionis GD, Diakonis VF, Yoo SH. Management of pediatric keratoconus - evolving role of corneal collagen cross-linking: an update. Indian J Ophthalmol 2013; 61:435-40. [PMID: 23925333 PMCID: PMC3775083 DOI: 10.4103/0301-4738.116070] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Accepted: 07/08/2013] [Indexed: 11/05/2022] Open
Abstract
Pediatric keratoconus demonstrates several distinctive management issues in comparison with adult keratoconus with respect to under-diagnosis, poor compliance and modifications in treatment patterns. The major concerns comprise of the accelerated progression of the disease in the pediatric age group and management of co-morbidities such as vernal keratoconjuntivitis. Visual impairment in pediatric patients may affect social and educational development and overall negatively impact their quality of life. The treatment algorithm between adults and pediatric keratoconus has been similar; comprising mainly of visual rehabilitation with spectacles, contacts lenses (soft or rigid) and keratoplasty (lamellar or penetrating) depending on the stage of the disease. There is a paradigm shift in the management of keratoconus, a new treatment modality, corneal collagen crosslinking (CXL), has been utilized in adult keratoconic patients halting the progression of the disease. CXL has been utilized for over a 10 year period and based on the evidence of efficacy and safety in the adult population; this treatment has been recently utilized in management of pediatric keratoconus. This article will present an update about current management of pediatric keratoconus with special focus on CXL in this age group.
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Affiliation(s)
- Vardhaman P Kankariya
- Bascom Palmer Eye Institute, Miller School of Medicine, University of Miami, Miami, Florida, USA
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Chaerkady R, Shao H, Scott SG, Pandey A, Jun AS, Chakravarti S. The keratoconus corneal proteome: loss of epithelial integrity and stromal degeneration. J Proteomics 2013; 87:122-31. [PMID: 23727491 DOI: 10.1016/j.jprot.2013.05.023] [Citation(s) in RCA: 118] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2013] [Revised: 04/12/2013] [Accepted: 05/14/2013] [Indexed: 01/06/2023]
Abstract
UNLABELLED Keratoconus is a thinning corneal dystrophy that begins in the early teenage years and ultimately requires cornea transplantation to restore vision. Here we conducted a highly sensitive mass spectrometric analysis of the epithelium and the stroma from keratoconus and normal donor corneas. We identified a total of 932 and 1157 proteins in the consolidated data of the epithelium and stroma, respectively. Technical replicates showed strong correlations (≥0.88) in levels of all common proteins, indicating very low technical variations in the data. Analysis of the most increased (≥1.5 fold) and decreased (≤0.8 fold) proteins in the keratoconus corneal epithelial protein extracts identified proteins related to dermal diseases, inflammation, epithelial stratification and mesenchymal changes. Increased proteins included keratins 6A, 16 and vimentin, while the iron transporter lactotransferrin was decreased. The keratoconus stromal proteome suggests endoplasmic reticular stress, oxidative stress and widespread decreases in many extracellular matrix proteoglycan core proteins, lumican and keratocan, collagen types I, III, V and XII. Marked increase in apoptosis and endocytosis-related proteins suggest degenerative changes in keratocytes, the resident cells of the stroma. This is the most comprehensive proteome analysis of the cornea that highlights similarities of keratoconus with other neurodegenerative diseases. BIOLOGICAL SIGNIFICANCE This study provides, to our knowledge, the most comprehensive proteomic analysis of the vision threatening disease keratoconus, which affects a significant portion of the US and global populations. Using iTRAQ and LC/MS/MS, we have identified significant changes in the human corneal epithelium and stromal proteome that correlate to in vivo clinical findings. The protein changes identified will lead to molecular insights into disease pathogenesis and provide candidate genes for genetic studies of keratoconus.
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Affiliation(s)
- Raghothama Chaerkady
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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Zhang Y, Mao X, Schwend T, Littlechild S, Conrad GW. Resistance of corneal RFUVA–cross-linked collagens and small leucine-rich proteoglycans to degradation by matrix metalloproteinases. Invest Ophthalmol Vis Sci 2013; 54:1014-25. [PMID: 23322569 DOI: 10.1167/iovs.12-11277] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Extracellular matrix metalloproteinases (MMPs) are thought to play a crucial role in corneal degradation associated with the pathological progression of keratoconus. Currently, corneal cross-linking by riboflavin and ultraviolet A (RFUVA) has received significant attention for treatment of keratoconus. However, the extent to which MMPs digest cross-linked collagen and small leucine-rich proteoglycans (SLRPs) remains unknown. In this study, the resistance of RFUVA-cross-linked collagens and SLRPs to MMPs has been investigated. METHODS To investigate the ability of MMPs to digest cross-linked collagen and SLRPs, a model reaction system using purified collagen type I, type IV, and nonglycosylated, commercially available recombinant SLRPs, keratocan, lumican, mimecan, decorin, and biglycan in solution in vitro has been compared using reactions inside an intact bovine cornea, ex vivo. RESULTS Our data demonstrate that corneal cross-linked collagen type I and type IV are resistant to cleavage by MMP-1, MMP-2, MMP-9, and MMP-13, whereas non-cross-linked collagen I, IV, and natively glycosylated SLRPs are susceptible to degradation by MMPs. In addition, both cross-linked SLRPs themselves and cross-linked polymers of SLRPs and collagen appear able to resist degradation. These results suggest that the interactions between SLRPs and collagen caused by RFUVA protect both SLRPs and collagen fibrils from cleavage by MMPs. CONCLUSIONS A novel approach for understanding the biochemical mechanism whereby RFUVA cross-linking stops keratoconus progression has been achieved.
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Affiliation(s)
- Yuntao Zhang
- Division of Biology, Kansas State University, Manhattan, Kansas 66506-4901, USA.
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Vinciguerra P, Albé E, Frueh BE, Trazza S, Epstein D. Two-year corneal cross-linking results in patients younger than 18 years with documented progressive keratoconus. Am J Ophthalmol 2012; 154:520-6. [PMID: 22633357 DOI: 10.1016/j.ajo.2012.03.020] [Citation(s) in RCA: 148] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2011] [Revised: 03/06/2012] [Accepted: 03/06/2012] [Indexed: 11/18/2022]
Abstract
PURPOSE To report refractive, topographic, aberrometric, and tomographic outcomes 24 months after corneal cross-linking (CXL) in patients up to 18 years of age with progressive keratoconus. DESIGN Prospective, interventional case series. METHODS Forty eyes underwent riboflavin-ultraviolet A-induced CXL. Uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), sphere and cylinder, topography, aberrometry, tomography, and endothelial cell counts were evaluated at baseline and at 1, 3, 6, 12, and 24 months. RESULTS Mean logarithm of the minimum angle of resolution baseline UCVA and BSCVA were 0.79 ± 0.21 and 0.39 ± 0.10, respectively. Mean UCVA and BSCVA at 2 years were 0.58 ± 0.18 and 0.20 ± 0.09, respectively. The improvement in UCVA and BSCVA was significant throughout the postoperative follow-up (P < .05). Mean spherical equivalent refraction showed a significant decrease of 1.57 diopters (D) at 24 months (P = .02). Mean baseline simulated keratometry was 46.32 D in the flattest meridian and 51.48 D in the steepest meridian; at 2 years, the values were 45.30 D (P = .04) and 50.21 D (P = .07), respectively. For a 3-mm pupil, there was a significant reduction (P < .05) in whole eye (total), corneal, higher-order, and astigmatic wavefront aberrations at 24 months. A significant difference (P < .05) in total coma and total spherical aberration 2 years after CXL also was observed. Mean baseline pupil center pachymetry decreased significantly (P = .04) at 6 months, but recovered by 12 months and remained stable thereafter through the 2-year follow-up. Endothelial cell counts did not change significantly (P = .32). CONCLUSIONS CXL improved UCVA and BSCVA in the study patients, most likely by significantly reducing corneal asymmetry and corneal as well as total wavefront aberrations.
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Affiliation(s)
- Paolo Vinciguerra
- Department of Ophthalmology, Istituto Clinico Humanitas, Rozzano-Milano, Italy
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Evaluation of collagen crosslinking in keratoconus eyes with Kera intracorneal ring implantation. Eur J Ophthalmol 2012; 22 Suppl 7:S62-8. [PMID: 21786268 DOI: 10.5301/ejo.5000020] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/13/2011] [Indexed: 01/14/2023]
Abstract
PURPOSE To assess the outcome of collagen crosslinking (CXL) in keratoconus eyes after implantation of Kera intracorneal ring segments. PATIENTS AND METHODS Twenty-one eyes of 13 patients with mild to moderate degree of keratoconus were included in this study. All eyes had uneventful surgery for Kera intracorneal ring segment implantation followed by collagen CXL treatment after at least 3 months of the implantation. Inclusion criteria were absence of corneal scarring and corneal thickness higher than 400 mm. Uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA), spherical equivalent and cylinder refraction, and the mean keratometric (K) values were evaluated preoperatively and postoperatively. RESULTS The mean age was 21.36 ± 4.46 years (range 16-28). Mean time between implantation of Kera ring and CXL was 4.56 ± 3.2 months. The mean baseline UCVA and BCVA were 0.05 ± 0.02 and 0.18 ± 0.1, respectively; after Kera ring, the mean UCVA and BCVA were 0.23 ± 0.17 and 0.39 ± 0.18 (p=0.000), respectively. Collagen CXL after Kera ring resulted in an additional change in UCVA and BCVA to become 0.23 ± 0.17 (p=0.951) and 0.41 ± 0.18 (p=0.08), respectively. Also, CXL results in an additional change in spherical equivalent, cylindrical, and mean keratometric values. The decrease in spherical equivalent, cylindrical, and mean keratometric value was 2.8 D (p<0.05), 2.1 D (p<0.05), and 2.5 D (p<0.05), respectively, after Kera ring treatment. An additional decrease of 0.11 D (p>0.05), 0.01 D (p>0.05), and 0.09 D (p>0.05) was obtained after CXL in each respective parameter. CONCLUSIONS Collagen CXL has an additive effect after Kera ring implantation and may be considered as an enhancement/stabilizing procedure.
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Dahl BJ, Spotts E, Truong JQ. Corneal collagen cross-linking: an introduction and literature review. ACTA ACUST UNITED AC 2012; 83:33-42. [PMID: 22153823 DOI: 10.1016/j.optm.2011.09.011] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2010] [Revised: 02/22/2011] [Accepted: 09/08/2011] [Indexed: 10/14/2022]
Abstract
BACKGROUND This literature review analyzes the scientific evidence available regarding corneal collagen cross-linking (CXL) as a treatment option for progressive keratectasia. METHODS A literature search was performed using dates from 1990 to August 2010 regarding CXL Specific areas of focus for the literature review include safety and efficacy of the procedure as a stand-alone treatment or when used in conjunction with Intacs® corneal implants (Addition Technology™) or photorefractive keratectomy (PRK). RESULTS A total of 50 clinical trials and studies were identified, 20 of which met the inclusion criteria. Results of the included literature support the conclusion that CXL is a safe and efficacious treatment for progressive keratectasia. The results of CXL alone have shown stabilization or improvement in the maximum keratometry readings, best-corrected visual acuity, uncorrected visual acuity, and spherical and cylinder refractive measurements. CXL has been shown to enhance the effects of Intacs and has been proven successful when used in conjunction with PRK. CONCLUSION CXL is an effective treatment for limiting the progression of keratectasia, thus reducing the need for penetrating keratoplasty. CXL has a similar side-effect profile and similar risk level as PRK.
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Affiliation(s)
- Brandon J Dahl
- Keller Army Community Hospital, West Point, and State University of New York, College of Optometry, New York, NY, USA.
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Balasubramanian P, Prabhakaran MP, Sireesha M, Ramakrishna S. Collagen in Human Tissues: Structure, Function, and Biomedical Implications from a Tissue Engineering Perspective. POLYMER COMPOSITES – POLYOLEFIN FRACTIONATION – POLYMERIC PEPTIDOMIMETICS – COLLAGENS 2012. [DOI: 10.1007/12_2012_176] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Shao H, Chaerkady R, Chen S, Pinto SM, Sharma R, Delanghe B, Birk D, Pandey A, Chakravarti S. Proteome profiling of wild type and lumican-deficient mouse corneas. J Proteomics 2011; 74:1895-905. [PMID: 21616181 PMCID: PMC3163732 DOI: 10.1016/j.jprot.2011.04.032] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2011] [Revised: 04/29/2011] [Accepted: 04/30/2011] [Indexed: 10/18/2022]
Abstract
To elucidate how the deficiency of a major corneal proteoglycan, lumican, affects corneal homeostasis, we used mass spectrometry to derive the proteome profile of the lumican-deficient and the heterozygous mouse corneas and compared these to the wild type corneal proteome. 2108 proteins were quantified in the mouse cornea. Selected proteins and transcripts were investigated by Western blot and quantitative RT-PCR, respectively. We observed major changes in the composition of the stromal extracellular matrix (ECM) proteins in the lumican-deficient mice. Lumican deficiency altered cellular proteins in the stroma and the corneal epithelium. The ECM changes included increases in fibril forming collagen type I, Collagen type VI, fibromodulin, perlecan, laminin β₂, collagen type IV, nidogen/entactin and anchoring collagen type VII in the Lum⁺/⁻ and the Lum⁻/⁻ mouse corneas, while the stromal proteoglycans decorin, biglycan and keratocan were decreased in the Lum⁻/⁻( corneas. Cellular protein changes included increases in alcohol dehydrogenase, superoxide dismutase and decreases in epithelial cytokeratins 8 and 14. We also detected proteins that are novel to the cornea. The proteomes will provide an insight into the lumican-deficient corneal phenotype of stromal thinning and loss of transparency and a better understanding of pathogenic changes in corneal and ocular dystrophies.
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Affiliation(s)
- HanJuan Shao
- Department of Medicine, the Johns Hopkins University School of Medicine, USA
| | - Raghothama Chaerkady
- McKusick-Nathans Institute of Genetic Medicine and Department of Biological Chemistry, the Johns Hopkins University School of Medicine, USA
- Institute of Bioinformatics, International Tech Park, India
| | - Shoujun Chen
- Department of Pathology and Cell Biology, University of South Florida, USA
| | - Sneha M. Pinto
- Institute of Bioinformatics, International Tech Park, India
- Manipal University, Madhav Nagar, India
| | - Rakesh Sharma
- Department of Neurochemistry, National Institute of Mental Health and Neuro Sciences, India
| | | | - David Birk
- Department of Pathology and Cell Biology, University of South Florida, USA
| | - Akhilesh Pandey
- McKusick-Nathans Institute of Genetic Medicine and Department of Biological Chemistry, the Johns Hopkins University School of Medicine, USA
- Department of Pathology and Oncology, the Johns Hopkins University School of Medicine, US
| | - Shukti Chakravarti
- Department of Medicine, the Johns Hopkins University School of Medicine, USA
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El-Raggal TM. Riboflavin-Ultraviolet A Corneal Cross-linking for Keratoconus. Middle East Afr J Ophthalmol 2011; 16:256-9. [PMID: 20404993 PMCID: PMC2855667 DOI: 10.4103/0974-9233.58418] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
PURPOSE To evaluate the safety, efficacy of riboflavin-ultraviolet A irradiation (UVA) corneal cross-linking and present refractive changes induced by the treatment in cases of keratoconus. MATERIALS AND METHODS The study includes 15 eyes of 9 patients with keratoconus with an average keratometric (K) reading less than 54 D and minimal corneal thickness greater than 420 microns. The corneal epithelium was removed manually within the central 8.5 mm diameter area and the cornea was soaked with riboflavin eye drops (0.1% in 20% dextran tau-500) for 30 minutes followed by exposure to UVA radiation (365 nm, 3 mW/cm(2)) for 30 minutes. During the follow-up period, uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), manifest refraction, slit lamp examination and topographic changes were recorded at the first week, first month, 3 and 6 months. RESULTS There was statistically significant improvement of UCVA from a preoperative mean of 0.11 +/- 0.07 (range 0.05-0.3) to a postoperative mean of 0.15 +/- 0.06 (range 0.1-0.3) (P < 0.05). None of the eyes lost lines of preoperative UCVA but 1 eye lost 1 line of preoperative BSCVA. The preoperative mean K of 49.97 +/- 2.81 D (range 47.20-51.75) changed to 48.34 +/- 2.64 D (range 45.75-50.40). This decrease in K readings was statistically significant (P < 0.05). All eyes developed minimal faint stromal haze that cleared in 14 eyes within 1 month. In only 1 eye, this resulted in a very faint corneal scar. Other sight threatening complications were not encountered in this series. Progression of the original disease was not seen in any of the treated eyes within 6 months of follow-up. CONCLUSION Riboflavin-UVA corneal cross-linking is a safe and promising method for keratoconus. Larger studies with longer follow up are recommended.
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Javadi MA, Feizi S, Kanavi MR, Faramarzi A, Hashemian J, Mirbabaee F. Acute Hydrops After Deep Anterior Lamellar Keratoplasty in a Patient With Keratoconus. Cornea 2011; 30:591-4. [DOI: 10.1097/ico.0b013e3181d92866] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Abstract
PURPOSE To evaluate the therapeutic effect of corneal cross-linking (CXL) in 2 cases of bullous keratopathy combined with corneal ulcer. METHODS Two patients (2 eyes) were recruited for the sake of the study. Both suffered from bullous keratopathy and presented a gradually deteriorating, vision-threatening, central corneal ulcer, despite intense local antibiotic therapy. The same surgical procedure was performed in both eyes. De-epithelialization of the affected corneas was accompanied by UV-A cross-linking and finally by the application of a therapeutic contact lens. Local antibiotic therapy was resumed after the procedure. RESULTS Within 24 hours of the treatment, both patients reported significant subjective improvement of their visual acuity and ocular discomfort. Clinical evaluation revealed improvement of the corneal ulcer and the bullous keratopathy associated with significant decrease of the corneal thickness and haziness. During the 2-month follow-up period, a significant improvement of visual acuity was recorded in both cases. CONCLUSION CXL should be considered as a potential adjuvant therapeutic tool in patients with combined bullous keratopathy and infectious keratitis, who are resistant to traditional topical therapy.
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Abstract
The collagens represent a family of trimeric extracellular matrix molecules used by cells for structural integrity and other functions. The three alpha chains that form the triple helical part of the molecule are composed of repeating peptide triplets of glycine-X-Y. X and Y can be any amino acid but are often proline and hydroxyproline, respectively. Flanking the triple helical regions (i.e., Col domains) are non-glycine-X-Y regions, termed non-collagenous domains. These frequently contain recognizable peptide modules found in other matrix molecules. Proper tissue function depends on correctly assembled molecular aggregates being incorporated into the matrix. This review highlights some of the structural characteristics of collagen types I-XXVIII.
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Järveläinen H, Sainio A, Koulu M, Wight TN, Penttinen R. Extracellular Matrix Molecules: Potential Targets in Pharmacotherapy. Pharmacol Rev 2009. [DOI: 10.1124/pr.109.001289 doi:dx.doi.org] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
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Järveläinen H, Sainio A, Koulu M, Wight TN, Penttinen R. Extracellular matrix molecules: potential targets in pharmacotherapy. Pharmacol Rev 2009; 61:198-223. [PMID: 19549927 PMCID: PMC2830117 DOI: 10.1124/pr.109.001289] [Citation(s) in RCA: 362] [Impact Index Per Article: 22.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The extracellular matrix (ECM) consists of numerous macromolecules classified traditionally into collagens, elastin, and microfibrillar proteins, proteoglycans including hyaluronan, and noncollagenous glycoproteins. In addition to being necessary structural components, ECM molecules exhibit important functional roles in the control of key cellular events such as adhesion, migration, proliferation, differentiation, and survival. Any structural inherited or acquired defect and/or metabolic disturbance in the ECM may cause cellular and tissue alterations that can lead to the development or progression of disease. Consequently, ECM molecules are important targets for pharmacotherapy. Specific agents that prevent the excess accumulation of ECM molecules in the vascular system, liver, kidney, skin, and lung; alternatively, agents that inhibit the degradation of the ECM in degenerative diseases such as osteoarthritis would be clinically beneficial. Unfortunately, until recently, the ECM in drug discovery has been largely ignored. However, several of today's drugs that act on various primary targets affect the ECM as a byproduct of the drugs' actions, and this activity may in part be beneficial to the drugs' disease-modifying properties. In the future, agents and compounds targeting directly the ECM will significantly advance the treatment of various human diseases, even those for which efficient therapies are not yet available.
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Affiliation(s)
- Hannu Järveläinen
- Department of Medicine, Turku University Hospital, Kiinamyllynkatu 4-8, FI-20520 Turku, Finland.
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Vinciguerra P, Albè E, Trazza S, Rosetta P, Vinciguerra R, Seiler T, Epstein D. Refractive, topographic, tomographic, and aberrometric analysis of keratoconic eyes undergoing corneal cross-linking. Ophthalmology 2009; 116:369-78. [PMID: 19167087 DOI: 10.1016/j.ophtha.2008.09.048] [Citation(s) in RCA: 302] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2008] [Revised: 09/24/2008] [Accepted: 09/26/2008] [Indexed: 11/29/2022] Open
Abstract
PURPOSE To report refractive, topographic, tomographic, and aberrometric outcomes 12 months after corneal cross-linking (CXL) in eyes with progressive advanced keratoconus. DESIGN Prospective, nonrandomized, single-center clinical study. PARTICIPANTS Twenty-eight eyes undergoing CXL between April and June 2006. INTERVENTION Riboflavin-ultraviolet A (UVA)-induced CXL included instillation of 0.1% riboflavin-20% dextrane solution 30 minutes before UVA irradiation and every 5 minutes for an additional 30 minutes during irradiation. MAIN OUTCOME MEASURES Uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), sphere and cylinder refraction, topography, tomography, aberrometry, and endothelial cell count were evaluated at baseline and at 1, 3, 6, and 12 months follow-up. RESULTS Mean baseline UCVA and BSCVA were 0.17+/-0.09 and 0.52+/-0.17, respectively; 12-month mean UCVA and BSCVA were 0.27+/-0.08 and 0.72+/-0.16, a statistically significant difference (P<0.05). Mean spherical equivalent refraction showed a significant decrease of 0.41 diopters (D). Mean baseline simulated keratometry (SIM K) flattest and steepest meridians and SIM K average were 46.10, 50.37, and 48.08 D, respectively; at 12 months, 40.22, 44.21, and 42.01 D, respectively, were recorded, a difference that was significant for all 3 indices (P<0.05). Mean average pupillary power (APP) changed significantly from 47.50 to 41.04 D at 12 months (P<0.05) and apical keratometry (AK) from 58.94 to 55.18 D (P<0.05). The treated eyes showed no deterioration of the Klyce indices at 6 months postoperatively, whereas the untreated (contralateral) eyes did show deterioration. For a 3-mm pupil, there was a significant reduction (P<0.05) in whole eye (total), corneal, higher order, and astigmatic wavefront aberrations. A significant difference (P<0.05) in total coma and total spherical aberration after CXL was also observed. Mean baseline pupil center pachymetry and total corneal volume decreased significantly (P<0.05) to 470.09+/-29.01 microm and 57.17+/-3.21 mm(3) from baseline values of 490.68+/-30.69 microm and 59.37+/-4.36 mm(3), respectively. Endothelial cell counts did not changed significantly (P=0.13). CONCLUSIONS Corneal cross-linking seems to be effective in improving UCVA and BSCVA in eyes with progressive keratoconus by significantly reducing corneal APP, AK, and corneal and total wavefront aberrations at 1 year postoperatively.
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Affiliation(s)
- Paolo Vinciguerra
- Department Ophthalmology, Istituto Clinico Humanitas, Rozzano, Milan, Italy.
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Xu X, Mannik J, Kudryavtseva E, Lin KK, Flanagan LA, Spencer J, Soto A, Wang N, Lu Z, Yu Z, Monuki ES, Andersen B. Co-factors of LIM domains (Clims/Ldb/Nli) regulate corneal homeostasis and maintenance of hair follicle stem cells. Dev Biol 2007; 312:484-500. [PMID: 17991461 PMCID: PMC2494569 DOI: 10.1016/j.ydbio.2007.09.052] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2007] [Revised: 08/18/2007] [Accepted: 09/12/2007] [Indexed: 12/28/2022]
Abstract
The homeostasis of both cornea and hair follicles depends on a constant supply of progeny cells produced by populations of keratin (K) 14-expressing stem cells localized in specific niches. To investigate the potential role of Co-factors of LIM domains (Clims) in epithelial tissues, we generated transgenic mice expressing a dominant-negative Clim molecule (DN-Clim) under the control of the K14 promoter. As expected, the K14 promoter directed high level expression of the transgene to the basal cells of cornea and epidermis, as well as the outer root sheath of hair follicles. In corneal epithelium, the transgene expression causes decreased expression of adhesion molecule BP180 and defective hemidesmosomes, leading to detachment of corneal epithelium from the underlying stroma, which in turn causes blisters, wounds and an inflammatory response. After a period of epithelial thinning, the corneal epithelium undergoes differentiation to an epidermis-like structure. The K14-DN-Clim mice also develop progressive hair loss due to dysfunctional hair follicles that fail to generate hair shafts. The number of hair follicle stem cells is decreased by at least 60% in K14-DN-Clim mice, indicating that Clims are required for hair follicle stem cell maintenance. In addition, Clim2 interacts with Lhx2 in vivo, suggesting that Clim2 is an essential co-factor for the LIM homeodomain factor Lhx2, which was previously shown to play a role in hair follicle stem cell maintenance. Together, these data indicate that Clim proteins play important roles in the homeostasis of corneal epithelium and hair follicles.
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Affiliation(s)
- Xiaoman Xu
- Departments of Medicine and Biological Chemistry, Division of Endocrinology, University of California, Irvine, California
| | - Jaana Mannik
- Departments of Medicine and Biological Chemistry, Division of Endocrinology, University of California, Irvine, California
| | - Elena Kudryavtseva
- Departments of Medicine and Biological Chemistry, Division of Endocrinology, University of California, Irvine, California
| | - Kevin K. Lin
- Departments of Medicine and Biological Chemistry, Division of Endocrinology, University of California, Irvine, California
| | - Lisa A. Flanagan
- Department of Pathology, University of California, Irvine, California
| | - Joel Spencer
- Departments of Medicine and Biological Chemistry, Division of Endocrinology, University of California, Irvine, California
| | - Amelia Soto
- Departments of Medicine and Biological Chemistry, Division of Endocrinology, University of California, Irvine, California
| | - Ning Wang
- Departments of Medicine and Biological Chemistry, Division of Endocrinology, University of California, Irvine, California
| | - Zhongxian Lu
- Departments of Medicine and Biological Chemistry, Division of Endocrinology, University of California, Irvine, California
| | - Zhengquan Yu
- Departments of Medicine and Biological Chemistry, Division of Endocrinology, University of California, Irvine, California
| | - Edwin S. Monuki
- Department of Pathology, University of California, Irvine, California
| | - Bogi Andersen
- Departments of Medicine and Biological Chemistry, Division of Endocrinology, University of California, Irvine, California
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Mazzotta C, Balestrazzi A, Traversi C, Baiocchi S, Caporossi T, Tommasi C, Caporossi A. Treatment of progressive keratoconus by riboflavin-UVA-induced cross-linking of corneal collagen: ultrastructural analysis by Heidelberg Retinal Tomograph II in vivo confocal microscopy in humans. Cornea 2007; 26:390-7. [PMID: 17457184 DOI: 10.1097/ico.0b013e318030df5a] [Citation(s) in RCA: 260] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
PURPOSE To assess ultrastructural stromal modifications after riboflavin-UVA-induced cross-linking of corneal collagen in patients with progressive keratoconus. METHODS This was a second-phase prospective nonrandomized open study in 10 patients with progressive keratoconus treated by riboflavin-UVA-induced cross-linking of corneal collagen and assessed by means of Heidelberg Retinal Tomograph II Rostock Corneal Module (HRT II-RCM) in vivo confocal microscopy. The eye in the worst clinical condition was treated for each patient. Treatment under topical anesthesia included corneal deepithelization (9-mm diameter) and instillation of 0.1% riboflavin phosphate-20% dextran T 500 solution at 5 minutes before UVA irradiation and every 5 minutes for a total of 30 minutes. UVA irradiation was 7 mm in diameter. Patients were assessed by HRT II-RCM confocal microscopy in vivo at 1, 3, and 6 months after treatment. RESULTS Rarefaction of keratocytes in the anterior and intermediate stroma, associated with stromal edema, was observed immediately after treatment. The observation at 3 months after the operation detected keratocyte repopulation in the central treated area, whereas the edema had disappeared. Cell density increased progressively over the postoperative period. At approximately 6 months, keratocyte repopulation was complete, accompanied by increased density of stromal fibers. No endothelial damage was observed at any time. CONCLUSIONS Reduction in anterior and intermediate stromal keratocytes followed by gradual repopulation has been confirmed directly in vivo in humans by HRT II-RCM confocal microscopy after riboflavin-UVA-induced corneal collagen cross-linking.
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Affiliation(s)
- Cosimo Mazzotta
- Department of Ophthalmology and Neurosurgery, University of Siena, Siena, Italy
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Zagon IS, Sassani JW, Myers RL, McLaughlin PJ. Naltrexone accelerates healing without compromise of adhesion complexes in normal and diabetic corneal epithelium. Brain Res Bull 2007; 72:18-24. [PMID: 17303503 DOI: 10.1016/j.brainresbull.2006.12.007] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2006] [Revised: 12/17/2006] [Accepted: 12/18/2006] [Indexed: 11/30/2022]
Abstract
Naltrexone (NTX) is an opioid antagonist that accelerates wound healing of corneal epithelium in normal and diabetic animals. Junctional complexes (hemidesmosomes) are important in establishing adhesion of the corneal epithelium to the stroma. This study was designed to examine whether NTX, at a concentration that enhances corneal re-epithelialization, influences the appearance and number of hemidesmosomes in Normal, diabetic (DB) (hyperglycemic), and DB animals receiving insulin (DB-IN) (normoglycemic), and treated topically with NTX (10(-4) M) or sterile vehicle (SV) for 7 days following abrasion. Electron microscopic analysis of the peripheral cornea 2 weeks after removal of the epithelium indicated hemidesmosomes that could be classified into four sectional profiles. No differences were detected in either the structure or the number of junctional complexes in the cornea between Normal, DB, or DB-IN groups receiving vehicle or treated with NTX. Moreover, the fine structure of the basal and suprabasal layers of the corneal epithelium in all groups--including those treated with NTX--were comparable. These results indicate that topical application of NTX accelerates diabetic corneal epithelial healing without causing morphologic abnormalities in the reassembly of adhesion structures. Furthermore, controlled and uncontrolled diabetes for up to 3 months does not affect corneal adhesion complexes when compared to normal corneas. Thus, recurrent erosion following abrasion of the diabetic cornea, with preservation of the basal lamina, cannot be explained by structural abnormalities in the reformation of the epithelial adhesion complex.
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Affiliation(s)
- Ian S Zagon
- Department of Neural & Behavioral Sciences, The Pennsylvania State University College of Medicine, Hershey, PA 17033, United States.
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Caporossi A, Baiocchi S, Mazzotta C, Traversi C, Caporossi T. Parasurgical therapy for keratoconus by riboflavin–ultraviolet type A rays induced cross-linking of corneal collagen. J Cataract Refract Surg 2006; 32:837-45. [PMID: 16765803 DOI: 10.1016/j.jcrs.2006.01.091] [Citation(s) in RCA: 297] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2005] [Accepted: 11/09/2005] [Indexed: 10/24/2022]
Abstract
PURPOSE To assess the effectiveness of riboflavin-ultraviolet type A rays induced cross-linking of corneal collagen in reducing progression of keratoconus and in improving visual acuity in patients with progressive keratoconus. SETTING Department of Ophthalmology, Siena University, Siena, Italy. METHODS This was a second-phase prospective nonrandomized open study. Starting in September 2004, 10 eyes of 10 patients (mean age 31.4 years) with bilateral keratoconus were treated by combined riboflavin-ultraviolet type A rays (UVA) collagen cross-linking. Radiant energy was 3 mW/cm2 or 5.4 joule/cm2 for a 30-minute exposure at 1 cm from the corneal apex. A complete ophthalmologic examination (uncorrected visual acuity [UCVA], sphere spectacles corrected visual acuity (SSCVA), best spectacle-corrected visual acuity [BSCVA]) was performed. Patients had corneal computerized topographic examination, linear scan optical tomography, endothelial cell count, ultrasound pachometry, intraocular pressure (IOP) evaluation, and HRT II system confocal microscopy at 1, 2, 3, and 6 months. After treatment, eyes were medicated and dressed with a soft contact lens. RESULTS Comparative preoperative and postoperative results showed increases of 3.6 lines for UCVA (P = .0000112), 1.85 lines for SSCVA (P = .00065), and 1.66 lines for BSCVA (P = .00071). Topographic analysis showed a mean K reduction of 2.1 +/- 0.13 diopters (D) in the central 3.0 mm. Statistical analysis of IOP and endothelial cell count did not show significant differences. Topo-aberrometric analysis findings of corneal symmetry showed a trend toward increasing corneal symmetry with a major reduction in asymmetry between vertical hemimeridians. CONCLUSIONS Refractive results showed a reduction of about 2.5 D in the mean spherical equivalent, topographically confirmed by the reduction in mean K. Results of surface aberrometric analysis showed improvement in morphologic symmetry with a significant reduction in comatic aberrations.
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Affiliation(s)
- Aldo Caporossi
- Department of Ophthalmological and Neurosurgical Sciences, Siena University, Siena, Italy
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Stepp MA. Corneal integrins and their functions. Exp Eye Res 2006; 83:3-15. [PMID: 16580666 DOI: 10.1016/j.exer.2006.01.010] [Citation(s) in RCA: 101] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2005] [Accepted: 01/02/2006] [Indexed: 12/13/2022]
Abstract
Integrins were first described just over 20 years ago and have been studied in the cornea by many groups interested in how the cornea functions in health and disease. There are a minimum of 12 different integrin heterodimers reported to be expressed by the major resident cells of the cornea: the corneal and limbal epithelial cells, keratocytes/fibroblasts, and corneal endothelial cells. These different integrin heterodimers play important and varied roles in maintaining the cornea and organizing how its cells interact with their surrounding extracellular matrix to maintain corneal clarity. In this review, an overview of the discovery and functions of integrins is provided along with a description of the current state of our knowledge of this large family of important proteins. While we have learned a lot about corneal integrins over the past 20 years, there is still much to learn. Areas where gaps in our knowledge of integrin functions in the cornea are slowing our progress in understanding corneal diseases and dystrophies at a molecular level are highlighted.
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Affiliation(s)
- Mary Ann Stepp
- Department of Anatomy, The George Washington University Medical Center, 2300 I Street N.W., Washington, DC 20037, USA.
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