Effect of Lifestyle Modification on Adipokine Levels in Obese Subjects with Insulin Resistance

Abstract

Res. 2003;11:1048 -1054. Objective: To study the effect of weight loss in response to a lifestyle modification program on the circulating levels of adipose tissue derived cytokines (adipokines) in obese individuals with insulin resistance. Research Methods and Procedures: Twenty-four insulinresistant obese subjects with varying degrees of glucose tolerance completed a 6-month program consisting of combined hypocaloric diet and moderate physical activity. Adipokines [leptin, adiponectin, resistin, tumor necrosis factor-␣ (TNF-␣), interleukin-6 (IL-6)] and highly sensitive C-reactive protein were measured before and after the intervention. Insulin sensitivity index was evaluated by the frequently sampled intravenous glucose tolerance test. Results: Participants had a 6.9 Ϯ 0.1 kg average weight loss, with a significant improvement in sensitivity index and reduction in plasma leptin (27.8 Ϯ 3 vs. 23.6 Ϯ 3 ng/mL, p ϭ 0.01) and IL-6 (2.75 Ϯ 1.51 vs. 2.3 Ϯ 0.91 pg/mL, p ϭ 0.012). TNF-␣ levels tended to decrease (2.3 Ϯ 0.2 vs. 1.9 Ϯ 0.1 pg/mL, p ϭ 0.059). Adiponectin increased significantly only among diabetic subjects. The reductions in leptin were correlated with the decreases in BMI (r ϭ 0.464, p Ͻ 0.05) and with changes in highly sensitive C-reactive protein (r ϭ 0.466, p Ͻ 0.05). Discussion: Weight reduction in obese individuals with insulin resistance was associated with a significant decrease in leptin and IL-6 and a tendency toward a decrease in circulating TNF-␣, whereas adiponectin was increased only in diabetic subjects. Further studies are needed to elucidate the relationship between changes of adipokines and the health benefits of weight loss.

The effects of acute exercise on serum adiponectin and resistin levels and their relation to insulin sensitivity in overweight males

“…This finding is in accordance with the available chronic exercise studies that did not find alterations in the levels of the hormone after aerobic training for several months (Giannopoulou et al 2005;Monzillo et al 2003). In conclusion, it appears that acute aerobic exercise does not result in immediate or prolonged alteration in adiponectin or resistin levels in healthy overweight individuals.…”

“…It seems that modifications in body weight or body composition might be responsible for alterations in adiponectin levels (Esposito et al 2003;Hulver et al 2002;Monzillo et al 2003). Recent reports indicate that in young obese men, adiponectin levels are increased following an improvement of the body composition and this is more important than the way training is performed (Hara et al 2005).…”

Resistin concentrations before and after weight loss in obese children

“…The higher serum resistin levels of girls compared to boys are in concordance with most studies in adults. 6,13,16 Besides sexual dimorphism of body fat distribution differences in the sex steroids are discussed to be responsible for the observed differences. 12,15,27,28 However, resistin concentrations have been reported to be independent of menstruation cycle and sex hormones in adult women 7 and resistin levels did not significantly differ between prepubertal and pubertal boys.…”

“…4,5 In crosssectional studies in adulthood, serum resistin was reported to be related to fat mass [6][7][8] and to insulin resistance, [9][10][11][12] while other reports reveal no correlations to BMI, percent body fat 11,[13][14][15] or to insulin sensitivity. 13,14,16,17 Longitudinal data are necessary to analyze the relationships between resistin, obesity, and insulin resistance. Despite the great number of cross-sectional studies, there are only few longitudinal studies in adulthood with small numbers of subjects concerning resistin levels in obesity with contradictory results.…”

“…Two longitudinal analyses revealed changes in serum resistin to be positively correlated with changes in fat mass or weight status 18,19 and mean insulin, 18 while other studies reported no changes of resistin in weight loss. 13,16,20 As a result of these controversial findings, the small number of longitudinal data and, most importantly, the lack of studies concerning resistin levels in children, we studied resistin serum levels in obese and lean children in relation to age, gender, puberty, and insulin resistance and measured resistin concentrations before and after weight loss.…”