Plasma levels of adiponectin in type 2 diabetic patients : relationship with exercise and metformin treatment

Abstract EN

Plasma concentrations of adiponectin, a novel adipose-specific protein, has recently been shown to have anti-inflammatory, antiatherogenic properties in vitro and beneficial metabolic effects in animals.

Lower plasma levels of adiponectin have been documented in human subjects with metabolic syndrome and coronary artery disease.

We investigated the level of this putative protective adipocytokine in type 2 diabetes patients, and studied the effect of various therapeutic modalities-namely exercise and treatment with metformin- on adiponectin level in diabetic patients.

Material and methods: It comprised 90 type 2 diabetic patients (divided into three groups; 30 patients were recruited in the metformin group, 30 patients in the exercise group and 30 diabetic patients in the placebo group); 30 healthy subjects were included as a control group.

A group of 30 diabetic patients were recruited for a randomized open placebo-controlled trial for 3 months therapy with metformin, and a group of 30 patients participated in a 3 months supervised exercise training program for 6 days/week for approximately 45 min at 65-80% peak oxygen consumption.

Blood samples were collected and metabolic variables and adiponectin levels were determined in all patients before initiation of the study and after intervension.

Results: The plasma adiponectin level was highly significantly low in the diabetic patients compared to the control subjects (5.7+2.1 versus 10.5+3.5 ug/ml, p<0.001).

Three months after metformin treatment, there were significant differences in mean plasma adiponectin levels, fasting plasma glucose level (p <0.05), HbAlc (p <0.05), fasting insulin (p <0.05) and insulin resistance (p <0.001) between the treatment groups.

The increase of plasma adiponectin was 77% more in the metformin group compared to the placebo group (9.9+3.5 versus 5.9±2.8 ug/ml, p <0.001).

Plasma adiponectin concentration was negatively correlated with BMI (r = -0.43), fasting glucose concentration [FPG] (r = -0.38), fasting insulin concentration [FI] (r = -0.63), insulin resistance [HOMA-IR] (r =-0.49) and serum triglyceride [TG] (r = -0.34) and positively correlated with serum HDL (r = 0.39) (all p<0.001).

Stepwise multivariate linear regression analyses showed that treatment status was the single significant variable related to the changes in plasma adiponectin.

No statistically significant