Potential roles of vitamin D binding protein in attenuating liver injury in sepsis

Background:In sepsis,vitamin D binding protein(VDBP)has been shown to be low-expressed.The current study examined the relationship between serum VDBP level and liver injury in sepsis patients,as well as in a mouse model for sepsis and in cultured liver epithelial cell line exposed to lipopolysaccharide(LPS).Methods:The human study included 78 sepsis patients and 50 healthy volunteers.Sepsis patients were categorized into sepsis survivor group(n=43)and sepsis non-survivor group(n=35)based on 28-day mortality for data analysis.Adult male C57BL/6 mice were subjected to cecal ligation and puncture(CLP).Serum samples were collected on day 1,3,5 and 7 to determine the levels of VDBP,25-hydroxyvitamin D[25(OH)D_(3)],1,25-dihydroxyvitamin D[1,25(OH)_(2)D_(3)],interleukin-6(IL-6)and tumor necrosis factor alpha(TNF-α).Potential protective effects of VDBP overexpression against LPS-induced liver damage were examined in cultured THLE2 cells.Results:Serum levels of VDBP,25(OH)D_(3),and 1,25(OH)_(2)D_(3)were significantly lower in sepsis patients vs.the healthy control(P<0.001),as well as in the sepsis non-survivor group vs.the sepsis survivor group(P<0.001,P=0.0338,or P=0.0013,respectively).Lower serum VDBP level was associated with higher Acute Physiology and Chronic Health Evaluation(APACHE)II score(r=−0.2565,P=0.0234)and Sequential Organ Failure Assessment score(r=−0.3522,P=0.0016),but lower serum albumin(ALB,r=0.4628,P<0.001)and total protein(TP,r=0.263,P=0.02).In CLP mice,there was a 5-day period of serum VDBP reduction,followed by return towards the baseline on day 7.VDBP was also decreased in LPS-treated THLE2 cells(P<0.001).VDBP overexpression reduced LPS-induced THLE2 damage.Reduced damage was associated with decreased oxidative stress and inactivation of the c-Jun N-terminal kinase signaling pathway.Conclusion:VDBP may be protective against sepsis-induced liver injury.

Associations between Vitamin D and Type 2 Diabetes Mellitus: The Role of Vitamin D Receptor and Binding Protein

Background: Type 2 diabetes mellitus (T2DM) is a chronic disease that is characterized by β-cell dysfunction and resistance for insulin. Vitamin D is necessary for insulin secretion so it is a crucial factor in the development of T2DM. This study was done to investigate the association between serum 25-hydroxy Vitamin D [25(OH)3D], VDR (Vitamin D receptor) and VDBP (Vitamin D binding protein) with type 2 diabetic patients compared to control subjects. Subjects and Methods: This study carried out 110 female patients who were previously diagnosed with type 2 diabetes and 110 age, sex and weight matched as controls. All participants were subjected to full history taking, clinical examination and assessment of fasting blood glucose, HbA1c , lipid profile, 25-hydroxy Vitamin D [25(OH)3D], VDR and VDBP. Results: Results showed that the level of 25(OH)3D was significantly lower in diabetic group compared to controls and was significantly negatively correlated with glycated hemoglobin, serum total cholesterol and low density lipoprotein cholesterol in type 2 DM. Decreasing Vitamin D level was significantly associated with decreasing VDR. No significant association was found between Vit D and VDBP levels. Conclusions: Vitamin D deficiency is frequent in diabetic patients and associated with poor control and outcome. This suggests a role of Vitamin D in the pathogenesis and control of T2DM. Serum VDBP in diabetes may be independent to the level of 25(OH)3D and needs further studies.