Troglitazone-induced changes in adiponectin do not affect endothelial function in diabetes

Area of Science:

• Endocrinology
• Cardiovascular Research
• Metabolic Syndrome

Background:

• Adiponectin is an adipokine linked to endothelial function.
• Troglitazone treatment can increase adiponectin levels.
• The impact of troglitazone-induced adiponectin increase on endothelial function in type 2 diabetes requires investigation.

Purpose of the Study:

• To investigate the relationship between elevated adiponectin levels due to troglitazone and endothelium-dependent vasodilation in type 2 diabetic patients.
• To assess the effect of troglitazone on vascular reactivity and endothelial activation markers.

Main Methods:

• A randomized, placebo-controlled, double-blinded study involving 72 type 2 diabetic patients.
• High-resolution ultrasound to measure brachial artery flow-mediated dilation (endothelium-dependent) and nitroglycerin-induced dilation (endothelium-independent).
• Laser Doppler perfusion imaging for forearm skin vascular reactivity assessment.

Main Results:

• Troglitazone treatment increased adiponectin levels by 75% but did not alter endothelium-dependent vasodilation or other vascular reactivity measures.
• No significant changes were observed in endothelial activation markers or skin receptor for advanced glycation end-products expression.
• Adiponectin levels correlated with changes in fasting plasma glucose, hemoglobin A1c, total cholesterol, and LDL-cholesterol.

Conclusions:

• The increase in adiponectin levels following troglitazone treatment is not associated with improved endothelium-dependent vasodilation in type 2 diabetic patients.
• Adiponectin does not appear to be a major determinant of endothelial function in this context.
• Troglitazone treatment did not affect receptor for advanced glycation end-products expression in the skin microcirculation.