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Cui W, Ma Y, Zhang L, Zhang L, Yao Q, Zhang J, Cheng Y, Zeng W, Liu Q, Liu F, Liang C. Neuregulin 1 improved gastric motility and reduced gastric inflammation by activating the α7nAChR through the cholinergic anti-inflammatory pathway in diabetic rats. Toxicol Appl Pharmacol 2025; 495:117205. [PMID: 39689756 DOI: 10.1016/j.taap.2024.117205] [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: 09/19/2024] [Revised: 12/02/2024] [Accepted: 12/10/2024] [Indexed: 12/19/2024]
Abstract
Diabetic gastroparesis (DGP), a prevalent complication of diabetes, is characterized by delayed gastric emptying and inflammation. The dorsal motor nucleus of the vagus (DMV) plays a crucial role in modulating gastric function via the vagus nerve. Neuregulin 1 (NRG1), which is present in the DMV and influences the autonomic nervous system, has an unclear role in DGP. This study aimed to investigate the expression of NRG1 in the DMV of Zucker diabetic fatty (ZDF) rats and to evaluate the impact of centrally administered NRG1 on gastric motility and inflammation, as well as the underlying mechanisms. Our findings revealed a decrease in NRG1 and choline acetyltransferase (ChAT) expression in the DMV of ZDF rats, corresponding to weakened gastric motility. Microinjection of AAV-NRG1 (overexpressed NRG1 by means of an adeno-associated viral vector delivery of NRG1) into the DMV enhanced gastric motility and increased vagal nerve discharge frequency. Moreover, AAV-NRG1 upregulated acetylcholine (Ach) and α7 nicotinic acetylcholine receptor (α7nAChR) expression in the gastric body, mitigating gastric inflammation. The beneficial effects of AAV-NRG1 were partially reversed by vagotomy or α7nAChR antagonism. These findings provide novel evidence that NRG1 in the DMV can stimulate Ach release and activate α7nAChRs, thereby reducing inflammation and restoring gastric motility via the vagus nerve. This implicates the NRG1 as a potential therapeutic target for DGP.
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Affiliation(s)
- Weigang Cui
- Department of Human Anatomy, Medical college of Jiaying University, Meizhou, China; Department of Human Anatomy and histoembryology, Xinxiang Medical University, Xinxiang, China; Institute of Neuroscience and Mental Health, Medical college of Jiaying University, Meizhou, China.
| | - Yuqi Ma
- Department of Human Anatomy and histoembryology, Xinxiang Medical University, Xinxiang, China; College of Pharmaceutical Sciences, Soochow University, Soochow, China
| | - Libin Zhang
- Department of Physiology and Pathophysiology, Xinxiang Medical University, Xinxiang, China
| | - Lei Zhang
- Institute of Neuroscience and Mental Health, Medical college of Jiaying University, Meizhou, China
| | - Qianyin Yao
- Department of Human Anatomy, Medical college of Jiaying University, Meizhou, China
| | - Jie Zhang
- Department of Human Anatomy, Medical college of Jiaying University, Meizhou, China
| | - Yatao Cheng
- Department of Human Anatomy, Medical college of Jiaying University, Meizhou, China
| | - Wenqin Zeng
- Department of Human Anatomy, Medical college of Jiaying University, Meizhou, China
| | - Qin Liu
- Department of Human Anatomy, Medical college of Jiaying University, Meizhou, China
| | - Fengyun Liu
- Department of Human Anatomy, Medical college of Jiaying University, Meizhou, China
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Costa CJ, Cohen MW, Goldberg DC, Mellado W, Willis DE. Nicotinamide Riboside Improves Enteric Neuropathy in Streptozocin-Induced Diabetic Rats Through Myenteric Plexus Neuroprotection. Dig Dis Sci 2023:10.1007/s10620-023-07913-5. [PMID: 36920665 DOI: 10.1007/s10620-023-07913-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Accepted: 03/03/2023] [Indexed: 03/16/2023]
Abstract
BACKGROUND Diabetes Mellitus causes a systemic oxidative stress due in part to the hyperglycemia and the reactive oxygen species generated. Up to 75% of diabetic patients present with an autonomic neuropathy affecting the Enteric Nervous System. Deficits in the human population are chronic dysmotilities with either increased (i.e., constipation) or decreased (i.e., diarrhea) total gastrointestinal transit times. These are recapitulated in the streptozocin-induced diabetic rat, which is a model of Type I Diabetes Mellitus. AIMS Examine the effects that a precursor of nicotinamide adenosine dinucleotide (NAD), nicotinamide riboside (NR), had on the development of dysmotility in induced diabetic rats and if fecal microbiota transplant (FMT) could produce the same results. MATERIALS AND METHODS Utilizing a 6-week treatment paradigm, NR was administered intraperitoneally every 48 h. Total gastrointestinal transit time was assessed weekly utilizing the carmine red method. Three weeks following hyperglycemic induction, FMT was performed between NR-treated animals and untreated animals. SIGNIFICANT RESULTS There is improvement in overall gastrointestinal transit time with the use of NR. 16S microbiome sequencing demonstrated decreased alpha and beta diversity in induced diabetic rats without change in animals receiving FMT. Improvements in myenteric plexus ganglia density in small and large intestines in diabetic animals treated with NR were seen. CONCLUSIONS NR treatment led to functional improvement in total gastrointestinal transit time in induced diabetic animals. This was associated with neuroprotection in the myenteric plexuses of both small and large intestines of induced diabetic rats. This represents an important first step in showing NR's benefit as a treatment for diabetic enteric neuropathy. Streptozocin-induced diabetic rats have improved transit times and increased myenteric plexus ganglia density when treated with intraperitoneal nicotinamide riboside.
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Affiliation(s)
- Christopher J Costa
- Quinnipiac University Frank H Netter MD School of Medicine, North Haven, CT, USA. .,Burke Neurological Institute, 785 Mamaroneck Ave, White Plains, NY, 10605, USA. .,Graduate Medical Education, Internal Medicine Residency, UConn Health, 263 Farmington Ave, Farmington, CT, 06030-1235, USA.
| | - Melanie W Cohen
- Burke Neurological Institute, 785 Mamaroneck Ave, White Plains, NY, 10605, USA
| | - David C Goldberg
- Burke Neurological Institute, 785 Mamaroneck Ave, White Plains, NY, 10605, USA.,Children's Hospital of Philadelphia, 3501 Civic Center Blvd, Philadelphia, PA, 19104, USA
| | - Wilfredo Mellado
- Burke Neurological Institute, 785 Mamaroneck Ave, White Plains, NY, 10605, USA
| | - Dianna E Willis
- Burke Neurological Institute, 785 Mamaroneck Ave, White Plains, NY, 10605, USA.,Weill Cornell Medicine Feil Family Brain and Mind Research Institute, New York, NY, USA
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Sprouse J, Sampath C, Gangula PR. Role of sex hormones and their receptors on gastric Nrf2 and neuronal nitric oxide synthase function in an experimental hyperglycemia model. BMC Gastroenterol 2020; 20:313. [PMID: 32967621 PMCID: PMC7513483 DOI: 10.1186/s12876-020-01453-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Accepted: 09/15/2020] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Gastroparesis, a condition of abnormal gastric emptying, is most commonly observed in diabetic women. To date, the role of ovarian hormones and/or gastric hormone receptors on regulating nitrergic-mediated gastric motility remains inconclusive. AIM The purpose of this study is to investigate whether sex hormones/their receptors can attenuate altered Nuclear factor (erythroid-derived 2)-like 2 (Nrf2), neuronal Nitric Oxide Synthase (nNOS) expression and nitrergic relaxation in gastric neuromuscular tissues exposed to in-vitro hyperglycemia (HG). METHODS Gastric neuromuscular sections from adult female C57BL/6 J mice were incubated in normoglycemic (NG, 5 mM) or hyperglycemic (30 mM or 50 mM) conditions in the presence or absence of selective estrogen receptor (ER) agonists (ERα /PPT or ERβ: DPN); or non-selective sex hormone receptor antagonists (ER/ICI 182,780, or progesterone receptor (PR)/ RU486) for 48 h. mRNA, protein expression and nitrergic relaxation of circular gastric neuromuscular strips were assessed. RESULTS Our findings in HG, compared to NG, demonstrate a significant reduction in ER, Nrf2, and nNOS expression in gastric specimens. In addition, in-vitro treatment with sex hormones and/or their agonists significantly (*p < 0.05) restored Nrf2/nNOSα expression and total nitrite production. Conversely, ER, but not PR, antagonist significantly reduced Nrf2/nNOSα expression and nitrergic relaxation. CONCLUSIONS Our data suggest that ER's can regulate nitrergic function by improving Nrf2/nNOS expression in experimental hyperglycemia.
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Affiliation(s)
- Jeremy Sprouse
- School of Graduate Studies, Meharry Medical College, Nashville, TN, 37208, USA.,Department of ODS & Research, School of Dentistry, Nashville, TN, 37208, USA
| | - Chethan Sampath
- Department of ODS & Research, School of Dentistry, Nashville, TN, 37208, USA
| | - Pandu R Gangula
- Department of ODS & Research, School of Dentistry, Nashville, TN, 37208, USA.
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Martins-Perles JVC, Bossolani GDP, Zignani I, de Souza SRG, Frez FCV, de Souza Melo CG, Barili E, de Souza Neto FP, Guarnier FA, Armani ALC, Cecchini R, Zanoni JN. Quercetin increases bioavailability of nitric oxide in the jejunum of euglycemic and diabetic rats and induces neuronal plasticity in the myenteric plexus. Auton Neurosci 2020; 227:102675. [PMID: 32474374 DOI: 10.1016/j.autneu.2020.102675] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 03/06/2020] [Accepted: 04/24/2020] [Indexed: 02/08/2023]
Abstract
Considering the antioxidant, neuroprotective, inflammatory and nitric oxide modulatory actions of quercetin, the aim of this study was to test the effect of quercetin administration in drinking water (40 mg/day/rat) on neuronal nitric oxide synthase (nNOS), vasoactive intestinal peptide (VIP), overall population of myenteric neurons (HuC/D) and nitric oxide (NO) levels in the jejunal samples from diabetic rats. Male Wistar rats were distributed into four groups (8 rats per group): euglycemic (E), euglycemic administered with quercetin (E+Q), diabetic (D) and diabetic administered with quercetin (D+Q). Rats were induced to diabetes with streptozotocin (35mg/kg/iv) and, after 120 days, the proximal jejunum were collected and processed for immunohistochemical (VIP, nNOS and HuC/D) and chemiluminescence (quantification of tissue NO levels) techniques. Diabetes mellitus reduced the number of nNOS-IR (immunoreactive) (p <0.05) and HuC/D-IR (p <0.001) neurons, however, promoted an increased morphometric area of nNOS-IR neurons (p <0.001) and VIP-IR varicosities (p <0.05). In D+Q group, neuroplasticity effects were observed on HuC/D-IR neurons, accompanied by a reduction of cell body area of neurons nNOS- and VIP-IR varicosities (p <0.05). The NO levels were increased in the E+Q (p <0.05) and D+Q group (p <0.001) compared to the control group. In conclusion, the results showed that quercetin supplementation increased the bioavailability of NO in the jejunum in euglycemic and mitigate the effects of diabetes on nNOS-IR neurons and VIP-IR varicosities in the myenteric plexus of diabetic rats.
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Affiliation(s)
| | - Gleison Daion Piovezana Bossolani
- Department of Morphological Sciences, Universidade Estadual de Maringá, Avenida Colombo, n 5790 Bloco O-33, Maringá, PR CEP 87020-900, Brazil
| | - Isabela Zignani
- Department of Morphological Sciences, Universidade Estadual de Maringá, Avenida Colombo, n 5790 Bloco O-33, Maringá, PR CEP 87020-900, Brazil
| | - Sara Raquel Garcia de Souza
- Department of Morphological Sciences, Universidade Estadual de Maringá, Avenida Colombo, n 5790 Bloco O-33, Maringá, PR CEP 87020-900, Brazil
| | - Flávia Cristina Vieira Frez
- Department of Morphological Sciences, Universidade Estadual de Maringá, Avenida Colombo, n 5790 Bloco O-33, Maringá, PR CEP 87020-900, Brazil
| | - Carina Guimarães de Souza Melo
- Department of Morphological Sciences, Universidade Estadual de Maringá, Avenida Colombo, n 5790 Bloco O-33, Maringá, PR CEP 87020-900, Brazil
| | - Emerson Barili
- Department of Statistic, Universidade Estadual de Maringá, Avenida Colombo, n 5790, Maringá, PR CEP 87020-900, Brazil
| | - Fernando Pinheiro de Souza Neto
- Department of Pathology Sciences, Universidade Estadual de Londrina (UEL), Rodovia Celso Garcia Cid
- Pr 445 Km 380, Londrina, PR CEP 86.057-970, Brazil
| | - Flávia Alessandra Guarnier
- Department of Pathology Sciences, Universidade Estadual de Londrina (UEL), Rodovia Celso Garcia Cid
- Pr 445 Km 380, Londrina, PR CEP 86.057-970, Brazil
| | - Alessandra Lourenço Cecchini Armani
- Department of Pathology Sciences, Universidade Estadual de Londrina (UEL), Rodovia Celso Garcia Cid
- Pr 445 Km 380, Londrina, PR CEP 86.057-970, Brazil
| | - Rubens Cecchini
- Department of Pathology Sciences, Universidade Estadual de Londrina (UEL), Rodovia Celso Garcia Cid
- Pr 445 Km 380, Londrina, PR CEP 86.057-970, Brazil
| | - Jacqueline Nelisis Zanoni
- Department of Morphological Sciences, Universidade Estadual de Maringá, Avenida Colombo, n 5790 Bloco O-33, Maringá, PR CEP 87020-900, Brazil.
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Llévenes P, Rodrigues-Díez R, Cros-Brunsó L, Prieto MI, Casaní L, Balfagón G, Blanco-Rivero J. Beneficial Effect of a Multistrain Synbiotic Prodefen® Plus on the Systemic and Vascular Alterations Associated with Metabolic Syndrome in Rats: The Role of the Neuronal Nitric Oxide Synthase and Protein Kinase A. Nutrients 2020; 12:E117. [PMID: 31906276 PMCID: PMC7019517 DOI: 10.3390/nu12010117] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Revised: 12/16/2019] [Accepted: 12/18/2019] [Indexed: 02/07/2023] Open
Abstract
A high fat diet (HFD) intake is crucial for the development and progression of metabolic syndrome (MtS). Increasing evidence links gut dysbiosis with the metabolic and vascular alterations associated with MtS. Here we studied the use of a combination of various probiotic strains together with a prebiotic (synbiotic) in a commercially available Prodefen® Plus. MtS was induced by HFD (45%) in male Wistar rats. Half of the MtS animals received Prodefen® Plus for 4 weeks. At 12 weeks, we observed an increase in body weight, together with the presence of insulin resistance, liver steatosis, hypertriglyceridemia and hypertension in MtS rats. Prodefen® Plus supplementation did not affect the body weight gain but ameliorated all the MtS-related symptoms. Moreover, the hypertension induced by HFD is caused by a diminished both nitric oxide (NO) functional role and release probably due to a diminished neuronal nitric oxide synthase (nNOS) activation by protein kinase A (PKA) pathway. Prodefen® Plus supplementation for 4 weeks recovered the NO function and release and the systolic blood pressure was returned to normotensive values as a result. Overall, supplementation with Prodefen® Plus could be considered an interesting non-pharmacological approach in MtS.
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Affiliation(s)
- Pablo Llévenes
- Department of Physiology, School of Medicine, Universidad Autónoma de Madrid, Calle de Arzobispo Morcillo 4, 28029 Madrid, Spain; (P.L.); (L.C.-B.); (G.B.)
| | - Raquel Rodrigues-Díez
- Department of Pharmacology and Therapeutics, School of Medicine, Universidad Autónoma de Madrid, Calle de Arzobispo Morcillo 4, 28029 Madrid, Spain;
- Center for Biomedical Research Network (CIBER) in Cardiovascular Diseases, Calle de Melchor Fernández Almagro 3, 28029 Madrid, Spain
- Research Institute University Hospital la Paz (IdIPaz), Calle de Pedro Rico 6, 28029 Madrid, Spain;
| | - Laia Cros-Brunsó
- Department of Physiology, School of Medicine, Universidad Autónoma de Madrid, Calle de Arzobispo Morcillo 4, 28029 Madrid, Spain; (P.L.); (L.C.-B.); (G.B.)
| | - Mᵃ Isabel Prieto
- Research Institute University Hospital la Paz (IdIPaz), Calle de Pedro Rico 6, 28029 Madrid, Spain;
- Department of General and Digestive Surgery, Hospital Universitario la Paz, Paseo de la Castellana 261, 28046 Madrid, Spain
| | - Laura Casaní
- Research Institute of Santa Creu i Sant Pau Hospital, Carrer de Sant Quintí 77–79, 08041 Barcelona, Spain;
| | - Gloria Balfagón
- Department of Physiology, School of Medicine, Universidad Autónoma de Madrid, Calle de Arzobispo Morcillo 4, 28029 Madrid, Spain; (P.L.); (L.C.-B.); (G.B.)
- Center for Biomedical Research Network (CIBER) in Cardiovascular Diseases, Calle de Melchor Fernández Almagro 3, 28029 Madrid, Spain
- Research Institute University Hospital la Paz (IdIPaz), Calle de Pedro Rico 6, 28029 Madrid, Spain;
| | - Javier Blanco-Rivero
- Department of Physiology, School of Medicine, Universidad Autónoma de Madrid, Calle de Arzobispo Morcillo 4, 28029 Madrid, Spain; (P.L.); (L.C.-B.); (G.B.)
- Center for Biomedical Research Network (CIBER) in Cardiovascular Diseases, Calle de Melchor Fernández Almagro 3, 28029 Madrid, Spain
- Research Institute University Hospital la Paz (IdIPaz), Calle de Pedro Rico 6, 28029 Madrid, Spain;
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McMenamin CA, Clyburn C, Browning KN. High-Fat Diet During the Perinatal Period Induces Loss of Myenteric Nitrergic Neurons and Increases Enteric Glial Density, Prior to the Development of Obesity. Neuroscience 2019; 393:369-380. [PMID: 30454864 DOI: 10.1016/j.neuroscience.2018.09.033] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 09/19/2018] [Accepted: 09/24/2018] [Indexed: 02/07/2023]
Abstract
Diet-induced obesity induces peripheral inflammation accompanied by a loss of myenteric neurons. Few studies, however, have investigated the effects of a high-fat diet (HFD) on either the development of myenteric neurons or prior to the occurrence of obesity. The present study assessed the effects of maternal HFD on the density and neurochemical phenotype of myenteric ganglia in the upper gastrointestinal tract. Sprague-Dawley rats were fed either a control or HFD (14% or 60% kcal from fat, respectively) from embryonic day 13; the fundus, corpus and duodenum were fixed thereafter at postnatal 2, 4, 6 and 12 weeks of age for subsequent immunohistochemical studies. While myenteric ganglion size did not differ throughout the study, HFD exposure decreased the number of nitrergic neurons by 6 weeks of age in all regions. This decrease was accompanied by a loss of PGP-immunoreactive neurons, suggesting a decline in myenteric neuronal number. HFD also increased myenteric plexus glial cell density in all regions by 4 weeks of age. These changes occurred in the absence of an increase in serum or gastric inflammatory markers. The present study suggests that exposure to a HFD during the perinatal time period results in glial proliferation and loss of inhibitory nitrergic neurons prior to the onset of obesity, suggesting that dietary alterations may affect gastrointestinal functions independently of increased adiposity or glycemic dysregulation.
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Affiliation(s)
- Caitlin A McMenamin
- Department of Neural and Behavioral Sciences, Penn State College of Medicine, Hershey, PA 17033, United States
| | - Courtney Clyburn
- Department of Neural and Behavioral Sciences, Penn State College of Medicine, Hershey, PA 17033, United States
| | - Kirsteen N Browning
- Department of Neural and Behavioral Sciences, Penn State College of Medicine, Hershey, PA 17033, United States.
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Bisphenol A Causes Liver Damage and Selectively Alters the Neurochemical Coding of Intrahepatic Parasympathetic Nerves in Juvenile Porcine Models under Physiological Conditions. Int J Mol Sci 2017; 18:ijms18122726. [PMID: 29244763 PMCID: PMC5751327 DOI: 10.3390/ijms18122726] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2017] [Revised: 12/02/2017] [Accepted: 12/12/2017] [Indexed: 12/27/2022] Open
Abstract
Bisphenol A (BPA) is an extremely common polymer that is used in typical everyday products throughout the world, especially in food and beverage containers. Within the last ten years, it has been found that the BPA monomer tends to leach into foodstuffs, and nanogram concentrations of it may cause a variety of deleterious health effects. These health problems are very evident in developing children and in young adults. The aim of this study was to expose developing pigs to dietary BPA at both legally acceptable and ten-fold higher levels. Livers that had been exposed to BPA showed vacuolar degeneration, sinusoidal dilatation, vascular congestion and glycogen depletion that increased with exposure levels. Furthermore, the livers of these models were then examined for irregularities and double-labeled immunofluorescence was used to check the innervated hepatic samples for varying neuronal expression of selected neuronal markers in the parasympathetic nervous system (PSNS). It was found that both the PSNS and all of the neuronal markers showed increased expression, with some of them being significant even at recommended safe exposure levels. The implications are quite serious since these effects have been observed at recommended safe levels with expression increasing in-line with exposure levels. The increased neuronal markers studied here have been previously correlated with behavioral/psychological disorders of children and young adults, as well as with childhood obesity and diabetes. However, further research must be performed in order to develop a mechanism for the above-mentioned correlations.
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Chaudhury A. Response: "Commentary: A Hypothesis for Examining Skeletal Muscle Biopsy-Derived Sarcolemmal nNOSµ as Surrogate for Enteric nNOSα Function". nNOS(skeletal muscle) may be Evidentiary for Enteric NO-Transmission Despite nNOSµ/α Differences. Front Med (Lausanne) 2016; 3:4. [PMID: 26942180 PMCID: PMC4761842 DOI: 10.3389/fmed.2016.00004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Accepted: 01/15/2016] [Indexed: 12/15/2022] Open
Affiliation(s)
- Arun Chaudhury
- Arkansas Department of Health and GIM Foundation , Little Rock, AR , USA
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Stenkamp-Strahm CM, Nyavor YEA, Kappmeyer AJ, Horton S, Gericke M, Balemba OB. Prolonged high fat diet ingestion, obesity, and type 2 diabetes symptoms correlate with phenotypic plasticity in myenteric neurons and nerve damage in the mouse duodenum. Cell Tissue Res 2015; 361:411-26. [PMID: 25722087 DOI: 10.1007/s00441-015-2132-9] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2014] [Accepted: 01/20/2015] [Indexed: 12/18/2022]
Abstract
Symptoms of diabetic gastrointestinal dysmotility indicate neuropathy of the enteric nervous system. Long-standing diabetic enteric neuropathy has not been fully characterized, however. We used prolonged high fat diet ingestion (20 weeks) in a mouse model to mimic human obese and type 2 diabetic conditions, and analyzed changes seen in neurons of the duodenal myenteric plexus. Ganglionic and neuronal size, number of neurons per ganglionic area, density indices of neuronal phenotypes (immunoreactive nerve cell bodies and varicosities per ganglion or tissue area) and nerve injury were measured. Findings were compared with results previously seen in mice fed the same diet for 8 weeks. Compared to mice fed standard chow, those on a prolonged high fat diet had smaller ganglionic and cell soma areas. Myenteric VIP- and ChAT-immunoreactive density indices were also reduced. Myenteric nerve fibers were markedly swollen and cytoskeletal protein networks were disrupted. The number of nNOS nerve cell bodies per ganglia was increased, contrary to the reduction previously seen after 8 weeks, but the density index of nNOS varicosities was reduced. Mice fed high fat and standard chow diets experienced an age-related reduction in total neurons, with bias towards neurons of sensory phenotype. Meanwhile, ageing was associated with an increase in excitatory neuronal markers. Collectively, these results support a notion that nerve damage underlies diabetic symptoms of dysmotility, and reveals adaptive ENS responses to the prolonged ingestion of a high fat diet. This highlights a need to mechanistically study long-term diet-induced nerve damage and age-related impacts on the ENS.
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Affiliation(s)
- Chloe M Stenkamp-Strahm
- Department of Biological Sciences, University of Idaho, 875 Perimeter Drive 3051, LSS 252, Moscow, ID, 83844-3051, USA
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Mizuno MS, Crisma AR, Borelli P, Schäfer BT, Silveira MP, Castelucci P. Distribution of the P2X2 receptor and chemical coding in ileal enteric neurons of obese male mice (ob/ob). World J Gastroenterol 2014; 20:13911-13919. [PMID: 25320527 PMCID: PMC4194573 DOI: 10.3748/wjg.v20.i38.13911] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Revised: 04/29/2014] [Accepted: 06/13/2014] [Indexed: 02/06/2023] Open
Abstract
AIM To investigate the colocalization, density and profile of neuronal areas of enteric neurons in the ileum of male obese mice. METHODS The small intestinal samples of male mice in an obese group (OG) (C57BL/6J ob/ob) and a control group (CG) (+/+) were used. The tissues were analyzed using a double immunostaining technique for immunoreactivity (ir) of the P2X2 receptor, nitric oxide synthase (NOS), choline acetyl transferase (ChAT) and calretinin (Calr). Also, we investigated the density and profile of neuronal areas of the NOS-, ChAT- and Calr-ir neurons in the myenteric plexus. Myenteric neurons were labeled using an NADH-diaphorase histochemical staining method. RESULTS The analysis demonstrated that the P2X2 receptor was expressed in the cytoplasm and in the nuclear and cytoplasmic membranes only in the CG. Neuronal density values (neuron/cm(2)) decreased 31% (CG: 6579 ± 837; OG: 4556 ± 407) and 16.5% (CG: 7796 ± 528; OG: 6513 ± 610) in the NOS-ir and calretinin-ir neurons in the OG, respectively (P < 0.05). Density of ChAT-ir (CG: 6200 ± 310; OG: 8125 ± 749) neurons significantly increased 31% in the OG (P < 0.05). Neuron size studies demonstrated that NOS, ChAT, and Calr-ir neurons did not differ significantly between the CG and OG groups. The examination of NADH-diaphorase-positive myenteric neurons revealed an overall similarity between the OG and CG. CONCLUSION Obesity may exert its effects by promoting a decrease in P2X2 receptor expression and modifications in the density of the NOS-ir, ChAT-ir and CalR-ir myenteric neurons.
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Yarandi SS, Srinivasan S. Diabetic gastrointestinal motility disorders and the role of enteric nervous system: current status and future directions. Neurogastroenterol Motil 2014; 26:611-24. [PMID: 24661628 PMCID: PMC4104990 DOI: 10.1111/nmo.12330] [Citation(s) in RCA: 137] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/29/2013] [Accepted: 02/18/2014] [Indexed: 02/06/2023]
Abstract
BACKGROUND Gastrointestinal manifestations of diabetes are common and a source of significant discomfort and disability. Diabetes affects almost every part of gastrointestinal tract from the esophagus to the rectum and causes a variety of symptoms including heartburn, nausea, vomiting, abdominal pain, diarrhea and constipation. Understanding the underlying mechanisms of diabetic gastroenteropathy is important to guide development of therapies for this common problem. Over recent years, the data regarding the pathophysiology of diabetic gastroenteropathy is expanding. In addition to autonomic neuropathy causing gastrointestinal disturbances the role of enteric nervous system is becoming more evident. PURPOSE In this review, we summarize the reported alterations in enteric nervous system including enteric neurons, interstitial cells of Cajal and neurotransmission in diabetic animal models and patients. We also review the possible underlying mechanisms of these alterations, with focus on oxidative stress, growth factors and diabetes induced changes in gastrointestinal smooth muscle. Finally, we will discuss recent advances and potential areas for future research related to diabetes and the ENS such as gut microbiota, micro-RNAs and changes in the microvasculature and endothelial dysfunction.
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Affiliation(s)
- S. S. Yarandi
- Division of Digestive Diseases; Emory University; Atlanta GA
- Atlanta VA Medical Center; Decatur Georgia USA
| | - S. Srinivasan
- Division of Digestive Diseases; Emory University; Atlanta GA
- Atlanta VA Medical Center; Decatur Georgia USA
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Abstract
Autonomic neuropathy complicates diabetes by increasing patient morbidity and mortality. Surprisingly, considering its importance, development and exploitation of animal models has lagged behind the wealth of information collected for somatic symmetrical sensory neuropathy. Nonetheless, animal studies have resulted in a variety of insights into the pathogenesis, neuropathology, and pathophysiology of diabetic autonomic neuropathy (DAN) with significant and, in some cases, remarkable correspondence between rodent models and human disease. Particularly in the study of alimentary dysfunction, findings in intrinsic intramural ganglia, interstitial cells of Cajal and the extrinsic parasympathetic and sympathetic ganglia serving the bowel vie for recognition as the chief mechanism. A body of work focused on neuropathologic findings in experimental animals and human subjects has demonstrated that axonal and dendritic pathology in sympathetic ganglia with relative neuron preservation represents one of the neuropathologic hallmarks of DAN but it is unlikely to represent the entire story. There is a surprising selectivity of the diabetic process for subpopulations of neurons and nerve terminals within intramural, parasympathetic, and sympathetic ganglia and innervation of end organs, afflicting some while sparing others, and differing between vascular and other targets within individual end organs. Rather than resulting from a simple deficit in one limb of an effector pathway, autonomic dysfunction may proceed from the inability to integrate portions of several complex pathways. The selectivity of the diabetic process appears to confound a simple global explanation (e.g., ischemia) of DAN. Although the search for a single unifying pathogenetic hypothesis continues, it is possible that autonomic neuropathy will have multiple pathogenetic mechanisms whose interplay may require therapies consisting of a cocktail of drugs. The role of multiple neurotrophic substances, antioxidants (general or pathway specific), inhibitors of formation of advanced glycosylation end products and drugs affecting the polyol pathway may be complex and therapeutic elements may have both salutary and untoward effects. This review has attempted to present the background and current findings and hypotheses, focusing on autonomic elements including and beyond the typical parasympathetic and sympathetic nervous systems to include visceral sensory and enteric nervous systems.
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Affiliation(s)
- Robert E Schmidt
- Department of Pathology and Immunology, Washington University School of Medicine, Saint Louis, MO, USA.
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High-fat diet ingestion correlates with neuropathy in the duodenum myenteric plexus of obese mice with symptoms of type 2 diabetes. Cell Tissue Res 2013; 354:381-94. [PMID: 23881404 DOI: 10.1007/s00441-013-1681-z] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Accepted: 06/13/2013] [Indexed: 02/08/2023]
Abstract
Obesity and type 2 diabetes are increasing in prevalence at an alarming rate in developed and developing nations and over 50% of patients with prolonged stages of disease experience forms of autonomic neuropathy. These patients have symptoms indicating disrupted enteric nervous system function including gastric discomfort, gastroparesis and intestinal dysmotility. Previous assessments have examined enteric neuronal injury within either type 1 diabetic or transgenic type 2 diabetic context. This study aims to assess damage to myenteric neurons within the duodenum of high-fat diet ingesting mice experiencing symptoms of type 2 diabetes, as this disease context is most parallel to the human condition and disrupted duodenal motility underlies negative gastrointestinal symptoms. Mice fed a high-fat diet developed symptoms of obesity and diabetes by 4 weeks. After 8 weeks, the total number of duodenal myenteric neurons and the synaptophysin density index were reduced and transmission electron microscopy showed axonal swelling and loss of neurofilaments and microtubules, suggesting compromised neuronal health. High-fat diet ingestion correlated with a loss of neurons expressing VIP and nNOS but did not affect the expression of ChAT, substance P, calbindin and CGRP. These results correlate high-fat diet ingestion, obesity and type 2 diabetes symptoms with a loss of duodenal neurons, biasing towards those with inhibitory nature. This pathology may underlie dysmotility and other negative GI symptoms experienced by human type 2 diabetic and obese patients.
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Tronchini EA, Trevizan AR, Tashima CM, Pereira RVF, Zanoni JN. Supplementation with 0.1% and 2% vitamin E in diabetic rats: analysis of myenteric neurons immunostained for myosin-V and nNOS in the jejunum. ARQUIVOS DE GASTROENTEROLOGIA 2013; 49:284-90. [PMID: 23329224 DOI: 10.1590/s0004-28032012000400010] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2012] [Accepted: 06/26/2012] [Indexed: 02/06/2023]
Abstract
CONTEXT Diabetes mellitus is a disease characterized by hyperglycemia that, when allowed to progress long-term untreated, develops vascular and neurological complications, which are responsible for the development of alterations in the enteric nervous system in diabetic patients. In the gastrointestinal tract, diabetes mellitus promotes motor and sensory changes, and in the reflex function of this system, causing gastroparesis, diarrhea, constipation, megacolon, slow gastrointestinal transit, gastric stasis and dilation with decreased or increased peristaltic contractions. Several studies have shown that oxidative stress is the main responsible for the vascular and neurological complications affecting the enteric nervous system of diabetics. OBJECTIVE The effects of 0.1% and 2% vitamin E on myosin-V- and nNOS-immunoreactive neurons in the jejunum of diabetic rats were investigated. METHODS Thirty rats were divided into the groups: normoglycemic, normoglycemic treated with 0.1% vitamin E, normoglycemic treated with 2% vitamin E, diabetic, diabetic treated with 0.1% vitamin E, and diabetic treated with 2% vitamin E. The neuronal density and areas of neuron cell bodies were determined. RESULTS Diabetes (diabetic group) significantly reduced the number of myosin-V-immunoreactive neurons compared with the normoglycemic group. The diabetic treated with 0.1% vitamin E and diabetic treated with 2% vitamin E groups did not exhibit a greater density than the D group (P>0.05). Nitrergic density did not change with diabetes (P>0.05). The areas of myosin-V- and nNOS-immunoreactive neurons significantly increased in the normoglycemic treated with 2% vitamin E and diabetic groups compared with the normoglycemic group. CONCLUSION Supplementation with 2% vitamin E had a neurotrophic effect only in the area of myosin-V-immunoreactive neurons compared with the diabetic group.
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Goto K, Kato G, Kawahara I, Luo Y, Obata K, Misawa H, Ishikawa T, Kuniyasu H, Nabekura J, Takaki M. In vivo imaging of enteric neurogenesis in the deep tissue of mouse small intestine. PLoS One 2013; 8:e54814. [PMID: 23382976 PMCID: PMC3561410 DOI: 10.1371/journal.pone.0054814] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2012] [Accepted: 12/17/2012] [Indexed: 01/30/2023] Open
Abstract
One of the challenges of using imaging techniques as a tool to study cellular physiology has been the inability to resolve structures that are not located near the surface of the preparation. Nonlinear optical microscopy, in particular two photon-excited fluorescence microscopy (2PM), has overcome this limitation, providing deeper optical penetration (several hundred µm) in ex vivo and in vivo preparations. We have used this approach in the gut to achieve the first in vivo imaging of enteric neurons and nerve fibers in the mucosa, submucosa, submucosal and myenteric plexuses, and circular and longitudinal muscles of the small intestine in H-line: Thy1 promoter GFP mice. Moreover, we obtained clear three-dimensional imaging of enteric neurons that were newly generated after gut transection and reanastomosis. Neurogenesis was promoted by oral application of the 5-HT4-receptor agonist, mosapride citrate (MOS). The number of newly generated neurons observed in mice treated with MOS for one week was 421±89 per 864,900 µm2 (n = 5), which was significantly greater than that observed in preparations treated with MOS plus an antagonist (113±76 per 864,900 µm2) or in 4 week vehicle controls (100±34 per 864,900 µm2) (n = 4 both). Most neurons were located within 100 µm of the surface. These results confirm that activation of enteric neural 5-HT4-receptor by MOS promotes formation of new enteric neurons. We conclude that in vivo 2PM imaging made it possible to perform high-resolution deep imaging of the living mouse whole gut and reveal formation of new enteric neurons promoted by 5-HT4-receptor activation.
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Affiliation(s)
- Kei Goto
- Department of Physiology II, Nara Medical University, School of Medicine, Kashihara, Nara, Japan
- Department of Molecular Pathology, Nara Medical University, School of Medicine, Kashihara, Nara, Japan
| | - Go Kato
- Division of Homeostatic Development, Department of Developmental Physiology, National Institute for Physiological Sciences, Okazaki, Aichi, Japan
| | - Isao Kawahara
- Department of Physiology II, Nara Medical University, School of Medicine, Kashihara, Nara, Japan
- Department of Molecular Pathology, Nara Medical University, School of Medicine, Kashihara, Nara, Japan
| | - Yi Luo
- Department of Molecular Pathology, Nara Medical University, School of Medicine, Kashihara, Nara, Japan
| | - Koji Obata
- Department of Physiology II, Nara Medical University, School of Medicine, Kashihara, Nara, Japan
| | - Hiromi Misawa
- Department of Physiology II, Nara Medical University, School of Medicine, Kashihara, Nara, Japan
| | - Tatsuya Ishikawa
- Division of Homeostatic Development, Department of Developmental Physiology, National Institute for Physiological Sciences, Okazaki, Aichi, Japan
| | - Hiroki Kuniyasu
- Department of Molecular Pathology, Nara Medical University, School of Medicine, Kashihara, Nara, Japan
| | - Junich Nabekura
- Division of Homeostatic Development, Department of Developmental Physiology, National Institute for Physiological Sciences, Okazaki, Aichi, Japan
| | - Miyako Takaki
- Department of Physiology II, Nara Medical University, School of Medicine, Kashihara, Nara, Japan
- Department of Molecular Pathology, Nara Medical University, School of Medicine, Kashihara, Nara, Japan
- * E-mail:
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Chang MJ, Xiao JH, Wang Y, Yan YL, Yang J, Wang JL. 2, 3, 5, 4'-Tetrahydroxystilbene-2-O-beta-D-glucoside improves gastrointestinal motility disorders in STZ-induced diabetic mice. PLoS One 2012; 7:e50291. [PMID: 23226517 PMCID: PMC3513302 DOI: 10.1371/journal.pone.0050291] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2012] [Accepted: 10/22/2012] [Indexed: 01/19/2023] Open
Abstract
Oxidative stress has recently been considered as a pivotal player in the pathogenesis of diabetic gastrointestinal dysfunction. We therefore investigated the role of 2, 3, 5, 4'-tetrahydroxystilbene-2-O-beta-D-glucoside (THSG) that has a strong anti-oxidant property, in diabetic gastrointestinal dysmotility as well as the underlying protective mechanisms. THSG restored the delayed gastric emptying and the increased intestinal transit in streptozotocin (STZ)-induced diabetic mice. Loss of neuronal nitric oxide synthase (nNOS) expression and impaired nonadrenergic, noncholinergic (NANC) relaxations in diabetic mice were relieved by long-term preventive treatment with THSG. Meanwhile, THSG (10(-7)~10(-4) mol/L) enhanced concentration-dependently NANC relaxations of isolated colons in diabetic mice. Diabetic mice displayed a significant increase in Malondialdehyde (MDA) level and decrease in the activity of glutathione peroxidase (GSH-Px), which were ameliorated by THSG. Inhibition of caspase-3 and activation of ERK phosphorylation related MAPK pathway were involved in prevention of enhanced apoptosis in diabetes afforded by THSG. Moreover, THSG prevented the significant decrease in PPAR-γ and SIRT1 expression in diabetic ileum. Our study indicates that THSG improves diabetic gastrointestinal disorders through activation of MAPK pathway and upregulation of PPAR-γ and SIRT1.
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Affiliation(s)
- Mu-Jun Chang
- Department of Pharmacology, Tongji Medical College, Huazhong University of Science and Technology, Hangkong Rode, Wuhan, China
| | - Jun-Hua Xiao
- Department of Pharmacology, Tongji Medical College, Huazhong University of Science and Technology, Hangkong Rode, Wuhan, China
| | - Yong Wang
- Department of Pharmacology, Tongji Medical College, Huazhong University of Science and Technology, Hangkong Rode, Wuhan, China
| | - Yong-Li Yan
- Department of Pharmacology, Tongji Medical College, Huazhong University of Science and Technology, Hangkong Rode, Wuhan, China
| | - Jun Yang
- Department of Pharmacology, Tongji Medical College, Huazhong University of Science and Technology, Hangkong Rode, Wuhan, China
| | - Jia-Ling Wang
- Department of Pharmacology, Tongji Medical College, Huazhong University of Science and Technology, Hangkong Rode, Wuhan, China
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Mizuno MS, Crisma AR, Borelli P, Castelucci P. Expression of the P2X₂ receptor in different classes of ileum myenteric neurons in the female obese ob/ob mouse. World J Gastroenterol 2012; 18:4693-4703. [PMID: 23002338 PMCID: PMC3442207 DOI: 10.3748/wjg.v18.i34.4693] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/13/2012] [Revised: 03/21/2012] [Accepted: 04/13/2012] [Indexed: 02/06/2023] Open
Abstract
AIM To examine whether the ob/ob mouse model of obesity is accompanied by enteric nervous system abnormalities such as altered motility. METHODS The study examined the distribution of the P2X₂ receptor (P2X₂R) in myenteric neurons of female ob/ob mice. Specifically, we used immunohistochemistry to analyze the co-expression of the P2X₂R with neuronal nitric oxide synthase (nNOS), choline acetyltransferase (ChAT), and calretinin (CalR) in neurons of the small intestine myenteric plexus in ob/ob and control female mice. In these sections, we used scanning confocal microscopy to analyze the co-localization of these markers as well as the neuronal density (cm²) and area profile (μm²) of P2X₂R-positive neurons. In addition, enteric neurons were labeled using the nicotinamide adenine dinucleotide (NADH) diaphorase method and analyzed with light microscopy as an alternate means by which to analyze neuronal density and area. RESULTS In the present study, we observed a 29.6% increase in the body weight of the ob/ob animals (OG) compared to the control group (CG). In addition, the average small intestine area was increased by approximately 29.6% in the OG compared to the CG. Immunoreactivity (IR) for the P2X₂R, nNOS, ChAT and CalR was detectable in the myenteric plexus, as well as in the smooth muscle, in both groups. This IR appeared to be mainly cytoplasmic and was also associated with the cell membrane of the myenteric plexus neurons, where it outlined the neuronal cell bodies and their processes. P2X₂R-IR was observed to co-localize 100% with that for nNOS, ChAT and CalR in neurons of both groups. In the ob/ob group, however, we observed that the neuronal density (neuron/cm²) of P2X₂R-IR cells was increased by 62% compared to CG, while that of NOS-IR and ChAT-IR neurons was reduced by 49% and 57%, respectively, compared to control mice. The neuronal density of CalR-IR neurons was not different between the groups. Morphometric studies further demonstrated that the cell body profile area (μm²) of nNOS-IR, ChAT-IR and CalR-IR neurons was increased by 34%, 20% and 55%, respectively, in the OG compared to controls. Staining for NADH diaphorase activity is widely used to detect alterations in the enteric nervous system; however, our qualitative examination of NADH-diaphorase positive neurons in the myenteric ganglia revealed an overall similarity between the two groups. CONCLUSION We demonstrate increases in P2X₂R expression and alterations in nNOS, ChAT and CalR IR in ileal myenteric neurons of female ob/ob mice compared to wild-type controls.
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Bagyánszki M, Bódi N. Diabetes-related alterations in the enteric nervous system and its microenvironment. World J Diabetes 2012; 3:80-93. [PMID: 22645637 PMCID: PMC3360223 DOI: 10.4239/wjd.v3.i5.80] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2011] [Revised: 04/06/2012] [Accepted: 05/11/2012] [Indexed: 02/05/2023] Open
Abstract
Gastric intestinal symptoms common among diabetic patients are often caused by intestinal motility abnormalities related to enteric neuropathy. It has recently been demonstrated that the nitrergic subpopulation of myenteric neurons are especially susceptible to the development of diabetic neuropathy. Additionally, different susceptibility of nitrergic neurons located in different intestinal segments to diabetic damage and their different levels of responsiveness to insulin treatment have been revealed. These findings indicate the importance of the neuronal microenvironment in the pathogenesis of diabetic nitrergic neuropathy. The main focus of this review therefore was to summarize recent advances related to the diabetes-related selective nitrergic neuropathy and associated motility disturbances. Special attention was given to the findings on capillary endothelium and enteric glial cells. Growing evidence indicates that capillary endothelium adjacent to the myenteric ganglia and enteric glial cells surrounding them are determinative in establishing the ganglionic microenvironment. Additionally, recent advances in the development of new strategies to improve glycemic control in type 1 and type 2 diabetes mellitus are also considered in this review. Finally, looking to the future, the recent and promising results of metagenomics for the characterization of the gut microbiome in health and disease such as diabetes are highlighted.
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Affiliation(s)
- Mária Bagyánszki
- Mária Bagyánszki, Nikolett Bódi, Department of Physiology, Anatomy and Neuroscience, Faculty of Science, University of Szeged, H-6726 Szeged, Hungary
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Voukali E, Shotton HR, Lincoln J. Selective responses of myenteric neurons to oxidative stress and diabetic stimuli. Neurogastroenterol Motil 2011; 23:964-e411. [PMID: 21914042 DOI: 10.1111/j.1365-2982.2011.01778.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
BACKGROUND Diabetes has a differential effect on different subpopulations of myenteric neurons. Our aim was to investigate an in vitro model to examine the pathways underlying the development of nerve changes in diabetes. METHODS The proportions of neuronal cell bodies containing vasoactive intestinal polypeptide (VIP), neuronal nitric oxide synthase (nNOS) and calbindin relative to the pan-neuronal marker HuC/D were quantified in wholemount preparations of the myenteric plexus of adult rat ileum using double labeling immunohistochemistry. Preparations were maintained in culture for 24 h in the presence and absence of stimuli mimicking the diabetic environment including oxidative stress, carbonyl stress, high glucose and advanced glycation end products (AGEs). Data were compared with the effect of streptozotocin-induced diabetes in vivo. KEY RESULTS Only oxidative stress in vitro produced the same pattern as observed in diabetes with an increase in VIP-, decrease in nNOS-, and no change in calbindin-positive neurons. Carbonyl stress and high glucose caused an increase in VIP-containing neurons without affecting nNOS expression. In contrast, exposure to AGEs only caused a decrease in nNOS-positive neurons. Calbindin expression was unaffected by any of the stimuli. The effects of the stimuli were prevented by the antioxidant, α-lipoic acid, or the carbonyl scavenger, aminoguanidine. CONCLUSIONS & INFERENCES The results provide evidence that oxidative stress is the common factor in the development of neuronal changes in diabetes; however, the mechanism by which oxidative stress occurs depends on the individual subpopulation of myenteric neurons examined. The presence of calbindin appears to protect myenteric neurons against harmful stimuli.
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Affiliation(s)
- E Voukali
- Department of Cell and Developmental Biology, University College London, Gower Street, London, UK
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20
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Cellini J, Zaura Jukic AM, LePard KJ. Neostigmine-induced contraction and nitric oxide-induced relaxation of isolated ileum from STZ diabetic guinea pigs. Auton Neurosci 2011; 165:178-90. [PMID: 21880552 DOI: 10.1016/j.autneu.2011.07.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2011] [Revised: 07/14/2011] [Accepted: 07/27/2011] [Indexed: 02/06/2023]
Abstract
Both delayed gastrointestinal transit and autonomic neuropathy have been documented in patients with diabetes mellitus. The mechanism of neostigmine, an agent that mimics release of acetylcholine from autonomic neurons by prokinetic agents, to contract smooth muscle, despite dysfunctional enteric neural pathways, was determined using isolated ilea from STZ-treated and control guinea pigs. Both bethanechol- and neostigmine-induced contractions were stronger in diabetic ileum. Bethanechol-induced contractions of control but not diabetic ileum were increased by low dose scopolamine suggesting reduced activation of presynaptic muscarinic autoreceptors in diabetic ileum. The muscarinic receptor antagonist 4-DAMP strongly, but the nicotinic receptor antagonist hexamethonium only weakly, reduced neostigmine-induced contractions of control and diabetic ilea. The amount of acetylcholine, inferred from tissue choline content, was increased in diabetic ileum. Nicotinic neural and noncholinergic postjunctional smooth muscle receptors contributed more strongly to neostigmine-induced contractions in diabetic than control ileum. Relaxation of diabetic ileum by exogenous nitric oxide generated from sodium nitroprusside was comparable to control ileum, but smooth muscle relaxation by l-arginine using neuronal nitric oxide synthase to generate nitric oxide was weaker in diabetic ileum with evidence for a role for inducible nitric oxide synthase. Despite autonomic neuropathy, neostigmine strongly contracted ileum from diabetic animals but by a different mechanism including stronger activation of postjunctional muscarinic receptors, greater synaptic acetylcholine, stronger activation of noncholinergic excitatory pathways, and weaker activation of inhibitory pathways. A selective medication targeting a specific neural pathway may more effectively treat disordered gastrointestinal transit in patients with diabetes mellitus.
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Affiliation(s)
- Joseph Cellini
- Department of Physiology, Chicago College of Osteopathic Medicine, Midwestern University, Downers Grove, IL, USA
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Savidge TC. S-nitrosothiol signals in the enteric nervous system: lessons learnt from big brother. Front Neurosci 2011; 5:31. [PMID: 21441985 PMCID: PMC3058138 DOI: 10.3389/fnins.2011.00031] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2010] [Accepted: 02/28/2011] [Indexed: 12/13/2022] Open
Abstract
Nitric oxide (NO) is a functionally important neurotransmitter signaling molecule generated by mammalian and bacterial nitric oxide synthases (NOS), and by chemical conversion of dietary nitrite in the gastrointestinal (GI) tract. Neuronal NOS (nNOS) is the most abundant isoenzyme in the enteric nervous system, and targeted deletion in transgenic mice has clearly demonstrated its importance in normal gut function. Enteric neuropathy is also often associated with abnormal NO production, for example in achalasia and diabetic gastroparesis. Not surprisingly therefore, aberrant nNOS activity is widely implicated in enteric disease, and represents a potential molecular target for therapeutic intervention. One physiological signaling mechanism of NO bioactivity is through chemical reaction with the heme center of guanylyl cyclase, resulting in the conversion of cGMP from GTP. This second messenger nucleotide signal activates cGMP-dependent protein kinases, phosphodiesterases, and ion channels, and is implicated in the neuronal control of GI function. However, few studies in the GI tract have fully related NO bioactivity with specific molecular targets of NO-derived signals. In the central nervous system (CNS), it is now increasingly appreciated that NO bioactivity is often actively transduced via S-nitrosothiol (SNO) signals rather than via activation of guanylyl cyclase. Moreover, aberrant S-nitrosylation of specific molecular targets is implicated in CNS pathology. S-nitrosylation refers to the post-translational modification of a protein cysteine thiol by NO, forming an endogenous SNO. Because cysteine residues are often key regulators of protein function, S-nitrosylation represents a physiologically important signaling mechanism analogous to other post-translational modifications, such as O-phosphorylation. This article provides an overview of how neurotransmitter NO is produced by nNOS as this represents the most prominent and well defined source of SNO production in the enteric nervous system. Further, it provides a perspective of how S-nitrosylation signals derived from multiple diverse sources may potentially transduce NO bioactivity in the GI tract. Possible lessons that might be learnt from the CNS, such as SNO mediated auto-inhibition of nNOS activity and modulation of neuronal cell death, are also explored as these may have pathophysiological relevance in enteric neuropathy. Thus, S-nitrosylation may mediate previously underappreciated NO-derived signals in the enteric nervous system that regulate homeostatic gut functions and disease susceptibility.
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Affiliation(s)
- Tor C Savidge
- Division of Gastroenterology and Hepatology, The University of Texas Medical Branch Galveston, TX, USA
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22
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Surendran S, Bhatnagar M. Upregulation of N-acetylaspartic acid induces oxidative stress to contribute in disease pathophysiology. Int J Neurosci 2011; 121:305-9. [PMID: 21348802 DOI: 10.3109/00207454.2011.558225] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
N-acetylaspartic acid (NAA) is predominantly present in brain and also present in lower amount in peripheral organs. The role of NAA in pathophysiology is poorly understood. Therefore the review was aimed to understand contribution of NAA in disease process. Amniotic fluid of mothers with Canavan disease (CD) fetus and patients with the disease show increased levels of NAA. Increase of this pathway is also reported in Parkinson's disease and type 2 diabetes. In HIV-related dementia, NAA is affected. Recent studies suggest that upregulation of NAA leads to oxidative stress including upregulation of nitric oxide and reducing potential antioxidants. NAA also leads to physiological abnormalities including walking disorder. These changes suggest that NAA contributes in disease pathophysiology.
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Damage of the interstitial cells of Cajal and myenteric neurons causing ileus in acute necrotizing pancreatitis rats. Surgery 2010; 149:262-75. [PMID: 20570303 DOI: 10.1016/j.surg.2010.04.023] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2009] [Accepted: 04/23/2010] [Indexed: 01/06/2023]
Abstract
BACKGROUND Small intestinal motility is impaired in acute necrotizing pancreatitis (ANP). The present study was designed to detect the impairment in small intestinal motility and to assess the role of interstitial cells of Cajal (ICC), myenteric neurons and the associated mechanism in the pathogenesis of ileus during experimentally induced acute pancreatitis. METHODS ANP was induced by intraperitoneal injections of 30% L-ornithine at a dose of 3 g/kg at hourly intervals. The alterations of small intestine electrical activity--migrating myoelectric complexes (MMCs), and slow waves--were measured 24 hr after ANP induction. The spontaneous mechanical activity and the contractile response to ACh, KCl, tetrodotoxin (TTX) and the nitric oxide synthase (NOS) inhibitor NG-nitro-L-arginine (L-NNA) were evaluated by organ bath technique, and the morphologic alterations of the network of ICC, myenteric neurons and neuronal nitric oxide synthase (nNOS) immunoreactive cells were evaluated using the markers of c-Kit, PGP9.5, and nNOS, respectively. To demonstrate the deficiencies in enteric neuronal origin, we also measured nNOS expression in the muscular layer of ileum. RESULTS L-ornithine-induced necrotizing pancreatitis manifests with multiple symptoms, including decreased amplitude of spontaneous contractions in small intestinal smooth muscle, declined contractile response to ACh, TTX, and L-NNA in vitro, disrupted MMC cycle length, decreased dominant frequency and dominant power of slow waves in vivo. Furthermore, the morphologic studies demonstrated the damage of ICC (ANP group versus control; P = .000), myenteric neurons (ANP group versus control; P = .001) and nNOS immunoreactive neurons (ANP group versus control; P = .000). We also observed a substantial loss in the expression of nNOS protein in muscular layer of the small intestine (ANP group versus control; P = .032). CONCLUSION Our results suggest that the pathogenesis of the small intestinal paralysis in ANP may be related to the deficiencies in ICC and nNOS neurons.
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Li C, Liu S, Guan Y, Qian W, du F, Hou X. Long pulse gastric electrical stimulation induces regeneration of myenteric plexus synaptic vesicles in diabetic rats. Neurogastroenterol Motil 2010; 22:453-e108. [PMID: 19886913 DOI: 10.1111/j.1365-2982.2009.01420.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
BACKGROUND Gastric electrical stimulation (GES) may improve delayed gastric emptying in diabetic gastroparesis, but whether enteric nervous system (ENS) is directly involved in its mechanism of improvement in gastric motility is unclear. The aims were to investigate the correlation between the changes in ENS and effects of long pulse GES on them in diabetic rats induced by streptozotocin (STZ). METHODS Electron microscopy, immunohistochemistry, RT-PCR and western blot were used to evaluate changes of myenteric plexus neurons and synaptic vesicles in different stages of the diabetic rats. The effects of GES were detected by same methods after pacing wires were implanted and then diabetes was induced and followed by long pulse GES. KEY RESULTS Since 6 weeks after STZ injection, the nerve fibres were incompact and synaptic vesicles in myenteric neurons reduced. Furthermore, the myenteric neurons showed severe damage such as partial depletion of the axon, swelling of mitochondria and seriously decreased synaptic vesicles in 12 weeks after STZ injection. The synaptophysin and PGP9.5-positive area and expressions of synaptophysin mRNA and protein decreased with the duration of diabetes. Long pulse GES could induce increase of myenteric neuronal synaptic vesicles, synaptophysin and PGP9.5-positive area and in myenteric plexus. The synaptophysin mRNA and protein expression rose after GES, whatever GES beginning early or late, short-term or long-term. CONCLUSIONS & INFERENCES The longer duration of diabetes, the more significant damages to myenteric neurons and synaptic vesicles of diabetic rats; long pulse GES could induce regeneration of myenteric plexus synaptic vesicles, thereby reform gastric motility.
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Affiliation(s)
- C Li
- Division of Gastroenterology, Union Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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Zandecki M, Vanden Berghe P, Depoortere I, Geboes K, Peeters T, Janssens J, Tack J. Characterization of myenteric neuropathy in the jejunum of spontaneously diabetic BB-rats. Neurogastroenterol Motil 2008; 20:818-28. [PMID: 18312542 DOI: 10.1111/j.1365-2982.2008.01091.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Decreased gastric expression and function of neuronal nitric oxide synthase (nNOS) has been proposed as a potential mechanism underlying diabetic gastroparesis. As gastric nNOS expression is vagally controlled, these changes might occur secondarily to vagal neuropathy. In addition, it is unclear whether other inhibitory neurotransmitters are also involved. We used the type 1 diabetic BioBreeding (BB)-rat model to study jejunal motor control and nNOS expression, which is independent of the vagus. Jejunal segments were used for in vitro contractility studies, and measurement of nNOS expression after 8 or 16 weeks of diabetes compared with age- and sex-matched controls. Unlike electrical field stimulation and acetylcholine (ACh)-induced contractions, non-adrenergic non-cholinergic (NANC) relaxations were significantly reduced in diabetic rats. In contrast to control rats, NANC relaxations in diabetic rats were N(omega)-nitro-L-arginine methyl ester (L-NAME) insensitive. Jejunal nNOS expression was significantly decreased in diabetic rats. Both in diabetic and in control animals, L-NAME resistant relaxations were sensitive to P(2)-receptor antagonists. In the jejunum of spontaneously diabetic rats, decreased nitric oxide responsiveness and decreased nNOS protein expression occur while purinergic transmission is unaffected. These findings indicate that nitrergic enteric neuropathy may be a primary dysfunction in diabetes, independent from vagal dysfunction.
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Affiliation(s)
- M Zandecki
- Center for Gastroenterological Research, Catholic University Leuven, Leuven, Belgium
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27
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Abstract
Diabetes is associated with several changes in gastrointestinal (GI) motility and associated symptoms such as nausea, bloating, abdominal pain, diarrhoea and constipation. The pathogenesis of altered GI functions in diabetes is multifactorial and the role of the enteric nervous system (ENS) in this respect has gained significant importance. In this review, we summarize the research carried out on diabetes-related changes in the ENS. Changes in the inhibitory and excitatory enteric neurons are described highlighting the role of loss of inhibitory neurons in early diabetic enteric neuropathy. The functional consequences of these neuronal changes result in altered gastric emptying, diarrhoea or constipation. Diabetes can also affect GI motility through changes in intestinal smooth muscle or alterations in extrinsic neuronal control. Hyperglycaemia and oxidative stress play an important role in the pathophysiology of these ENS changes. Antioxidants to prevent or treat diabetic GI motility problems have therapeutic potential. Recent research on the nerve-immune interactions demonstrates inflammation-associated neurodegeneration which can lead to motility related problems in diabetes.
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Affiliation(s)
- B Chandrasekharan
- Division of Digestive Diseases, Emory University, Atlanta, GA 30322, USA
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28
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Surendran S. Upregulation of N-acetylaspartic acid alters inflammation, transcription and contractile associated protein levels in the stomach and smooth muscle contractility. Mol Biol Rep 2007; 36:201-6. [PMID: 17943458 DOI: 10.1007/s11033-007-9167-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2007] [Accepted: 10/05/2007] [Indexed: 12/29/2022]
Abstract
N-acetylaspartic acid (NAA) is converted into aspartate and acetate by aspartoacylase. Abnormal levels of the enzyme leads to accumulation of NAA and these changes have been observed in Canavan disease and type 2 diabetes. How upregulation of NAA affect the gastrointestine protein levels and the function is not known. Incubation of rat stomach tissue with NAA 1.5 mM, 1.5 microM and 1.5 nM induced inflammatory agents TNFalpha, p38MAPK, iNOS, PKC, COX2 and ICAM3; transcription factors phospho-NF-kBp65, cjun and cfos; contractile proteins MLCK and phospho MLC; and calcium channel alpha1C and calcium channel, voltage-dependent, beta 3 subunit compared to their respective control. Incubation of circular smooth muscle cells with the above doses of NAA induced contractility compared to the control. These studies suggest that NAA alters proteins levels and smooth muscle contractility and these changes likely to contribute to gastrointestinal disorder seen in these diseases.
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Affiliation(s)
- Sankar Surendran
- Department of Pediatrics, University of Texas Health Science Center, Houston, TX 77030, USA.
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29
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Surendran S. Fas (CD95) alters neuronal nitric oxide synthase expression to contribute in diabetic gastroparesis. Med Hypotheses 2007; 68:1427. [PMID: 17161551 DOI: 10.1016/j.mehy.2006.11.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2006] [Accepted: 11/01/2006] [Indexed: 10/23/2022]
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Kang DI, Kim SH, Lee SD, Kwak HS, Choi SH, Kim DR, Min KS. Effects of Alpha-lipoic Acid on Nitric Oxide Synthase Expression and Ultrastructural Changes in the Bladder of Rats with Streptozotocin-induced Diabetes. Korean J Urol 2007. [DOI: 10.4111/kju.2007.48.2.212] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Dong Il Kang
- Department of Urology, Inje University College of Medicine, Busan, Korea
| | - Sun Hyun Kim
- Paik Institute of Clinical Research, Busan, Korea
| | - Sang Don Lee
- Department of Urology, Pusan National University College of Medicine, Busan, Korea
| | - Ho Sup Kwak
- Department of Urology, Inje University College of Medicine, Busan, Korea
| | - Sung Hyup Choi
- Department of Urology, Inje University College of Medicine, Busan, Korea
| | - Do Ri Kim
- Department of Urology, Inje University College of Medicine, Busan, Korea
| | - Kweon Sik Min
- Department of Urology, Inje University College of Medicine, Busan, Korea
- Paik Institute of Clinical Research, Busan, Korea
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