The observed effect was robust in sensitivity analyses and independent of fibrate dose .
The present meta- analysis suggests that fibrate therapy increases circulating levels of adiponectin .
BACKGROUND Several lines of evidence have indicated the insulin-sensitizing , anti-diabetic and anti-atherosclerotic properties of adiponectin , as well as the inverse association between circulating levels of this adipokine and development of cardiovascular outcomes .
Improvement of adiponectin status has been reported as a pleiotropic effect of fibrate therapy , but the findings have not been conclusive .
OBJECTIVE To systematic ally review and meta-analyze available evidence from r and omized placebo-controlled trials ( RCTs ) on the impact of fibrate therapy on circulating levels of adiponectin .
The effect of thiazolidinediones on plasma adiponectin levels in normal, obese, and type 2 diabetic subjects.
The insulin-sensitizing effects of thiazolidinediones are thought to be mediated through peroxisome proliferator-activated receptor-gamma , a nuclear receptor that is highly abundant in adipose tissue . It has been reported that adipocytes secrete a variety of proteins , including tumor necrosis factor-alpha , resistin , plasminogen activator inhibitor-1 , and adiponectin . Adiponectin is a fat cell-secreted protein that has been reported to increase fat oxidation and improve insulin sensitivity . Our aim was to study the effects of troglitazone on adiponectin levels in lean , obese , and diabetic subjects . Ten diabetic and 17 nondiabetic subjects ( 8 lean , BMI < 27 kg/m(2 ) and 9 obese , BMI > 27 kg/m(2 ) ) participated in the study . All subjects underwent an 80 mU. m(-2 ) . min(-1 ) hyperinsulinemic-euglycemic glucose clamp before and after 3 months ' treatment with the thiazolidinedione ( TZD ) troglitazone ( 600 mg/day ) . Fasting plasma glucose significantly decreased in the diabetic group after 12 weeks of treatment compared with baseline ( 9.1 + /- 0.9 vs. 11.1 + /- 0.9 mmol/l , P < 0.005 ) but was unchanged in the lean and obese subjects . Fasting insulin for the entire group was significantly lower than baseline ( P = 0.02 ) after treatment . At baseline , glucose disposal rate ( R(d ) ) was lower in the diabetic subjects ( 3.4 + /- 0.5 mg . kg(-1 ) . min(-1 ) ) than in the lean ( 12.3 + /- 0.4 ) or obese subjects ( 6.7 + /- 0.7 ) ( P < 0.001 for both ) and was significantly improved in the diabetic and obese groups ( P < 0.05 ) after treatment , and it remained unchanged in the lean subjects . Baseline adiponectin levels were significantly lower in the diabetic than the lean subjects ( 9.0 + /- 1.7 vs. 16.7 + /- 2.7 micro g/ml , P = 0.03 ) and rose uniformly in all subjects ( 12.2 + /- 2.3 vs. 25.7 + /- 2.6 micro g/ml , P < 10(-4 ) ) after treatment , with no significant difference detected among the three groups . During the glucose clamps , adiponectin levels were suppressed below basal levels in all groups ( 10.2 + /- 2.3 vs. 12.2 + /- 2.3 micro g/ml , P < 0.01 ) . Adiponectin levels correlated with R(d ) ( r = 0.46 , P = 0.016 ) and HDL cholesterol levels ( r = 0.59 , P < 0.001 ) and negatively correlated with fasting insulin ( r = -0.39 , P = 0.042 ) and plasma triglyceride ( r = -0.61 , P < 0.001 ) . Our findings show that TZD treatment increased adiponectin levels in all subjects , including normal subjects in which no other effects of TZDs are observed . Insulin also appears to suppress adiponectin levels . We have confirmed these results in normal rats . These findings suggest that adiponectin can be regulated by obesity , diabetes , TZDs , and insulin , and it may play a physiologic role in enhancing insulin sensitivity
The observed effect was robust in sensitivity analyses and independent of fibrate dose .
The present meta- analysis suggests that fibrate therapy increases circulating levels of adiponectin .
BACKGROUND Several lines of evidence have indicated the insulin-sensitizing , anti-diabetic and anti-atherosclerotic properties of adiponectin , as well as the inverse association between circulating levels of this adipokine and development of cardiovascular outcomes .
Improvement of adiponectin status has been reported as a pleiotropic effect of fibrate therapy , but the findings have not been conclusive .
OBJECTIVE To systematic ally review and meta-analyze available evidence from r and omized placebo-controlled trials ( RCTs ) on the impact of fibrate therapy on circulating levels of adiponectin .