| Title | Reductions in plasma cytokine levels with weight loss improve insulin sensitivity in overweight and obese postmenopausal women. | | Author(s) | Ryan AS, Nicklas BJ | | Institution | Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, USA. aryan@grecc.umaryland.edu | | Source | Diabetes Care 2004 Jul; 27(7):1699-705. | | MeSH | Aged
Blood Glucose
Body Composition
Body Mass Index
Cytokines
Glucose Clamp Technique
Humans
Hyperinsulinism
Inflammation
Insulin
Male
Middle Aged
Obesity
Postmenopause
Regression Analysis
Research Support, U.S. Gov't, Non-P.H.S.
Research Support, U.S. Gov't, P.H.S.
Weight Loss
| | Abstract | OBJECTIVE: The purpose of this study was to determine whether improvements in insulin sensitivity with weight loss are mediated by changes in inflammation in obese, postmenopausal women.
RESEARCH DESIGN AND METHODS: We studied 58 sedentary, overweight, and obese (BMI 33 +/- 1 kg/m(2), means +/- SEM) postmenopausal (58 +/- 1 year) women at baseline and 37 women who completed 6 months of weight loss induced by diet and exercise. The women underwent 3-h hyperinsulinemic-euglycemic clamps (40 mU x m(-2) x min(-1)) to determine glucose utilization (M). Insulin sensitivity was determined as M/I, the amount of glucose metabolized per unit of plasma insulin (I). Visceral adipose tissue (VAT) and plasma concentrations of C-reactive protein (CRP), cytokines interleukin (IL)-6, and tumor necrosis factor (TNF)-alpha, as well as their soluble receptors, were measured.
RESULTS: At baseline, CRP concentration was a predictor of both glucose utilization and insulin sensitivity, independent of adiposity, race, and aerobic fitness (M: partial r = -0.30, P = 0.03, and M/I: partial r = -0.32, P = 0.02). Weight loss resulted in significant reductions in body weight, fat mass, VAT, and fasting glucose and insulin levels (P < 0.05). Both glucose utilization and insulin sensitivity increased by 16% (P < 0.05). CRP, IL-6, and soluble TNF receptor (sTNFR)-1 concentrations decreased (P < 0.05), but concentrations of TNF-alpha, sTNFR-2, and soluble IL-6 receptor (IL-6sR) did not change. In stepwise regression models to predict changes in glucose homeostasis, changes in VAT and sTNF-R1 independently predicted changes in glucose utilization (r = -0.49 and cumulative r = -0.64, P < 0.01), while changes in VAT and IL-6 were both independent predictors of changes in insulin sensitivity (r = -0.57 and cumulative r = -0.68, P < 0.01).
CONCLUSIONS: Improvements in glucose metabolism with weight loss programs are independently associated with decreases in cytokine concentrations, suggesting that a reduction in inflammation is a potential mechanism that mediates improvements in insulin sensitivity. | | Language | eng | | Pub Type(s) | Journal Article
| | PubMed ID | 15220249 |
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