OBJECTIVE: In this study, the associations between vitamin D, insulin sensitivity, and inflammation and their relationships with adipose tissue expression of vitamin D receptor (VDR) and inflammatory markers in women with morbid obesity were determined. METHODS: An oral glucose tolerance test prior to surgery was completed by healthy premenopausal women (n = 76) seeking bariatric surgery. Abdominal subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) were collected during surgery. RESULTS: Approximately, 70% of our subjects were vitamin D sufficient or optimal, and 80% had normal glucose tolerance. No significant association between serum 25-hydroxyvitamin D [25(OH)D] with circulating inflammatory markers or insulin sensitivity was identified. In subjects with waist circumference of <139 cm (n = 42), log25(OH)D positively predicted VAT logIL-6 mRNA expression (P = 0.003). LogVDR expression was positively correlated with the expression of inflammatory markers in both SAT (logIL-1β mRNA: r = 0.95, P < 0.0001; logTNF mRNA: r = 0.82, P < 0.0001) and VAT (logIL-1β mRNA: r = 0.89, P < 0.0001; logTNF mRNA: r = 0.75, P < 0.0001). VAT logVDR expression positively predicted logHOMA-IR in non-African American subjects (P = 0.05). CONCLUSIONS: The beneficial effects of vitamin D on inflammation and insulin sensitivity were not supported by our findings. VDR does not appear to possess a protective effect in adipose tissue.
OBJECTIVE: In this study, the associations between vitamin D, insulin sensitivity, and inflammation and their relationships with adipose tissue expression of vitamin D receptor (VDR) and inflammatory markers in women with morbid obesity were determined. METHODS: An oral glucose tolerance test prior to surgery was completed by healthy premenopausal women (n = 76) seeking bariatric surgery. Abdominal subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) were collected during surgery. RESULTS: Approximately, 70% of our subjects were vitamin D sufficient or optimal, and 80% had normal glucose tolerance. No significant association between serum 25-hydroxyvitamin D [25(OH)D] with circulating inflammatory markers or insulin sensitivity was identified. In subjects with waist circumference of <139 cm (n = 42), log25(OH)D positively predicted VAT logIL-6 mRNA expression (P = 0.003). LogVDR expression was positively correlated with the expression of inflammatory markers in both SAT (logIL-1β mRNA: r = 0.95, P < 0.0001; logTNF mRNA: r = 0.82, P < 0.0001) and VAT (logIL-1β mRNA: r = 0.89, P < 0.0001; logTNF mRNA: r = 0.75, P < 0.0001). VAT logVDR expression positively predicted logHOMA-IR in non-African American subjects (P = 0.05). CONCLUSIONS: The beneficial effects of vitamin D on inflammation and insulin sensitivity were not supported by our findings. VDR does not appear to possess a protective effect in adipose tissue.
Authors: Clare F Dix; Judith D Bauer; Ian Martin; Sharon Rochester; Briony Duarte Romero; Johannes B Prins; Olivia R L Wright Journal: Nutrients Date: 2017-10-04 Impact factor: 5.717