Possible impairment of transcardiac utilization of adiponectin in patients with type 2 diabetes

OBJECTIVE - Adiponectin, an adipocyte-derived protein, has been suggested to enhance insulin sensitivity and prevent atherosclerosis. Circulating adiponecin levels are reduced in states of insulin resistance such as type 2 diabetes. We examined transcardiac utilization of adiponectin in patients with and without type 2 diabetes. RESEARCH DESIGN AND METHODS - A total of 17 male type 2 diabetic patients and 17 male nondiabetic patients were investigated. Venous blood samples were taken to measure glucose and lipid variables. Blood samples for the measurement of adiponectin were collected simultaneously from the aortic root and coronary sinus. Angiographic semiquantitative stenosis score of coronary artery was also evaluated. RESULTS - The adiponectin levels in both the aortic root and coronary sinus in the diabetic patients were significantly lower than those in the nondiabetic patients. The adiponectin level was significantly lower in the coronary sinus than in the aortic root in the nondiabetic patients, but there was no significant difference between adiponectin levels in the aortic root and coronary sinus in the diabetic patients. The total stenosis score, as an index of severity of coronary artery stenosis, was significantly higher in the diabetic Patients than in the nondiabetic patients. The stenosis score was correlated with the degree of transcardiac utilization of adiponectin from the aortic root to coronary sinus in the nondiabetic patients but not in the diabetic patients. CONCLUSIONS - Diabetic patients not only have a decreased adiponectin level in the basal state compared with nondiabetic patients but also have impaired utilization of adiponectin in the coronary artery and/or the heart, which may promote the development of atherosclerosis.