Copyright ©The Author(s) 2015.
World J Gastroenterol. Feb 14, 2015; 21(6): 1718-1727
Published online Feb 14, 2015. doi: 10.3748/wjg.v21.i6.1718
Table 1 Potential mechanisms and evidence to support a benefit for vitamin D in non-alcoholic fatty liver disease
Improvement in insulin secretion and insulin resistancePresence of VDR in pancreatic beta cells[26]
Expression of 1-α-hydroxylase enzyme in pancreatic beta cells[79]
Impaired insulin secretory response in mice lacking a functional VDR[13]
Transcriptional activation of the human insulin gene by 1,25(OH)2D[80]
Vitamin D deficiency impairs glucose-mediated insulin secretion from rat pancreatic beta cells in vitro[81] and in vivo[82]
Vitamin D enhances insulin responsiveness for glucose transport in muscle cells[83]
Vitamin D up-regulates glucose transporter 4 (GLUT4) translocation and glucose utilization in adipocytes[44]
Improvement in adipose tissue inflammationHigher 25(OH)D concentrations were independently associated with higher adiponectin concentrations in a large cohort of men and women[40]
Reduction of IL-6 in adipocytes after supplementation of vitamin D in mice fed high fat diet[84]
1,25-dihydroxyvitamin D treatment in human adipocytes inhibits NF-κB pathway and reduces pro-inflammatory cytokine release[85,86]
1,25-dihydroxyvitamin D inhibits macrophage recruitment and increases adiponectin expression in preadipocytes[87]
Improvement in hepatic inflammationVitamin D deficiency causes TLR activation and exacerbates hepatic inflammation[42]
Artificial sunlight therapy in rats reduced liver inflammation and apoptosis[43]
VDR expression on cholangiocytes was inversely correlated with steatosis severity and nonalcoholic fatty liver disease score in NASH patients[31]
Improvement in hepatic fibrosisPresence of VDR in HSC[24]
Vitamin D treatment suppresses HSC proliferation in cultured HSC from rats[73]
Vitamin D treatment downregulates pro-fibrotic marker TIMP-1 and collagen type I production in cultured HSCs[73,74]
VDR knockout mice develop spontaneous liver injury with fibrosis[30]