Decreased plasma adiponectin concentrations in patients with syndrome X.

Objective: The levels of adiponectin, an anti-atherogenic protein, are decreased in patients with coronary artery disease. Syndrome X is associated with endothelial dysfunction, which is a key feature in the evolution of atherosclerosis. We sought to determine whether serum adiponectin levels are decreased in patients with syndrome X.

Methods: Twenty-three syndrome X patients (14 men, 9 women) who presented with stable angina pectoris, had a positive non-invasive stress test or an abnormal myocardial perfusion scintigraphy single photon emission computed tomography (MPS SPECT) and a normal coronary angiogram, were included in our study, as were 17 asymptomatic healthy subjects (13 men, 4 women) with normal results from non-invasive stress testing. The serum adiponectin levels and lipid profiles of the patients and control subjects were determined with venous samples collected after a 12-hour fast. The results were analysed by a Mann Whitney U test.

Results: Mean age (54.1 +/- 11.8 y in patients and 59.8 +/- 9.6 y in control subjects, P > 0.05) and body mass index (28.0 +/- 3.3 in patients and 27.1 +/- 4.2 in control subjects, P > 0.05) did not differ between the two groups. Adiponectin levels in patients with syndrome X (1.5 +/- 1.1 microg/dl) were significantly lower than those in the control group (5.3 +/- 2.9 microg/dl, P < 0.0001). Serum total cholesterol (TCHOL), triglyceride (TG), LDL, and HDL-cholesterol levels did not differ between the two groups (P > 0.05).

Conclusion: Serum adiponectin levels were lower in patients with syndrome X, and these low adiponectin concentrations may cause endothelial dysfunction. Thus, patients with a marked drop in adiponectin levels may be considered at high risk for future coronary events and may therefore benefit from additional pharmacological treatment.