Associations between Tissue Visfatin/Nicotinamide, Phosphoribosyltransferase (Nampt), Retinol Binding Protein-4, and Vaspin Concentrations and Insulin Resistance in Morbidly Obese Subjects

Abstract

Visfatin/Nampt, vaspin, and retinol binding protein-4 (RBP-4) play an important role in insulin resistance. The objectives of this study were to measure visfatin/Nampt, vaspin, and RBP-4 concentrations in blood, liver, muscle, subcutaneous, omental, and mesenteric adipose tissues in morbidly obese subjects and investigate their relationship to insulin resistance. Blood and tissue samples were collected from 38 morbidly obese subjects during Roux-en-Y surgery. Insulin resistance biomarkers were measured using standard kits. Visfatin/Nampt, vaspin, and RBP-4 gene expression levels in tissues were measured using real-time PCR. Their protein concentrations in blood and tissues were measured using ELISA kits. Diabetic subjects had significantly higher homeostasis model of assessment-insulin resistance and age and lower blood HDL-cholesterol concentrations than nondiabetic and prediabetic subjects. Diabetic and prediabetic subjects had significantly higher blood concentrations of visfatin/Nampt and vaspin than nondiabetic subjects. Liver RBP-4 concentrations were positively associated with blood glucose concentrations. Blood insulin resistance biomarker levels were positively associated with visfatin/Nampt concentrations in omental adipose tissue and liver, and vaspin concentrations in mesenteric adipose tissue. In conclusion, the correlations of visfatin/Nampt, vaspin, and RBP-4 with insulin resistance are tissue dependent.

Comparison of serum vaspin levels and vaspin expression in adipose tissue and smooth muscle tissue in pregnant women with and without gestational diabetes

“…Vaspin expression has been found in human adipose tissue as well as stomach, liver, pancreas, placenta and muscle tissue . While the specific tissues secreting the most vaspin remain unknown, Mm et al .…”

“…The added adipogenesis of SAT, with improved IR, is likely associated with an upregulation in vaspin gene expression in SAT . Goktas et al . also found the expressions of vaspin in SAT, VAT and rectus abdominis muscle were different in obese subjects in both normal, prediabetic and diabetic groups.…”

“…Vaspin expression has been found in human adipose tissue as well as stomach, 18 liver, pancreas, 19 placenta 12,20 and muscle tissue. 21 While the specific tissues secreting the most vaspin remain unknown, Mm et al 13 found that the expression of vaspin mRNA and protein in SAT was higher in pregnant women with GDM than in a control group.…”

Insulin induces expression of the hepatic <i>vaspin</i> gene

“…In addition, vaspin mRNA level was higher in OLETF rats than in non-diabetic control rats [1]. Further, vaspin expression was observed in humans [4,5] or mice [6] in several tissues such as adipose tissue, liver, skeletal muscle, pancreas, and skin, with the highest production being observed in the liver or skin.…”

Serum visfatin level in obese Egyptian children and adolescents and its relation with metabolic syndrome

“…Such conflicting data may be attributed to the difference in the specificity of the immunoassays used in the different studies [24]. Moreover, Goktas et al [25] (2013) concluded that correlations of visfatin with insulin resistance markers are tissue dependent.…”