Endocrine Abstracts

In the current study, we aimed to illustrate determinants of VDR gene expression in visceral and subcutaneous adipose tissues among obese and morbidly obese adults. We gathered visceral and subcutaneous adipose tissues during an elective abdominal surgery form 33 morbidly obese (body mass index (BMI) >40 kg/m²) and 23 obese (BMI = 30–40 kg/m²) participants who were free of diabetes. Before the surgery, dietary intake, physical activity, anthropometric indices, and biochemical variables were collected. The gene expressions VDR in visceral and subcutaneous adipose tissue were assessed by Real–Time PCR. Multiple linear regression models were used to examine predictors of VDR gene expression among weight–based categorized participants after adjusting age, BMI, WC, 25(OH)D, HOMA–IR, calcium intake, and physical activity. The mean age of the obese and morbid obese was 42.3 and 36.7 years, respectively) and BMI of the obese and morbid obese was 34.4 and 47.7 kg/m². There was no significant deference between obese and morbidly obese participants in mean VDR gene expression in visceral and subcutaneous adipose tissues. Among obese participants, 25(OH)D (β = –0.103, P = 0.036) was negatively, and BMI (β = 0.292, P = 0.052) and HOMA–IR (β = 0.285, P = 0.052) were positively associated with VDR mRNA levels in visceral adipose tissue. In morbidly obese participants, the independent positive predictors of VDR gene expression in visceral fat were BMI (β = 0.309, P = 0.007) and HOMA–IR (β = 0.362, P = 0.004), and negative predictors were 25(OH)D (β = –0.114, P = 0.042) and calcium intake (β = –0.307, P = 0.008). Our findings suggested that 25(OH)D concentration is the fundamental element of VDR gene expression in visceral fat which by increasing fat depots, the subsequent insulin resistance became another predictor of VDR gene expression. Further studies will be required to unravel the physiological consequences of the different adipose tissue response of VDR gene expression depending on the degree of obesity and its relevance in clinical practice, as well as to confirm the role of VDR in glucose hemostasis.