Plasma levels of endothelin and early carotid atherosclerosis in diabetic patients

An increased thickness of the carotid artery wall is thought to be a sign o f early atherosclerosis. Since plasma endothelin concentrations were releas ed from vascular endothelial cells, we have investigated the possible relat ionship between endothelin I (ET-1) and arterial wall thickness. Ninety-eig ht patients with Type 2 diabetes without evidence of macroangiopathy, hyper tension, proteinuria or proliferative retinopathy, and 50 non-diabetic subj ects were studied. After an overnight fast, blood was taken for ET-1, gluco se, HbA(1C), lipids, insulin and C-peptide. Arterial wall thickness was mea sured as the mean of the maximum intimal-medial thickness (IMT) in 16 carot id segments by B-mode ultrasound. ET-1 levels were significantly elevated i n diabetic patients with IMT > 1100 mum, 8.3 pmol/l (5.2-12.9) compared wit h control subjects, 7.6 pmol/l (5.0-11.0), p <0.01 and with diabetic subjec ts with IMT < 500 mum, 7.43 pmol/l (4.8-11.1), p <0.01. The diabetic (IMT > 1100 mum) study group had also significantly higher levels of insulin, 102 .8 +/- 46.4 pmol/l vs control subjects, 77.5 +/- 32.4 pmol/l, p <0.01. In d iabetic subjects, no correlation was found between ET-1 and IMT with glucos e, HbA(1C), lipids, age or duration of diabetes, respectively. We conclude that ET-1 levels are elevated in Type 2 diabetic patients with increased IM T. Thus providing further support for the role of endothelin in atheroscler osis.