Cholesterol metabolism, endothelial dysfunction, and carotid artery stiffness in type 1 diabetes

BackgroundType 1 diabetes is associated with increased risk of cardiovascular diseases and altered metabolism of cholesterol. We studied whether the markers of arterial stiffness reflecting preclinical atherosclerosis are related to markers of cholesterol metabolism in type 1 diabetes.MethodsIn eighteen type 1 diabetes subjects aged from 20 to 56 years, serum squalene and non-cholesterol sterols were measured with gas–liquid chromatography, and carotid arterial stiffness (elastic and Young’s modulus, beta index, distensibility, and compliance), intima-media thickness (IMT), and brachial artery endothelial function (flow-mediated dilatation, FMD) were measured with ultrasound imaging.ResultsVariables of arterial stiffness were not related to serum lipids or HbA1c except Young’s modulus and compliance to triglycerides (r = 0.541 and r = −0.552, p < 0.05 for both, respectively). Stiffness of carotid artery was related to mean blood pressure (elastic modulus r = 0.590, distensibility r = −0.486, p < 0.05 for both). Stiffness of carotid artery was associated with serum desmosterol concentration, marker of cholesterol synthesis (e.g. compliance r = −0.600, p < 0.01), and with markers of cholesterol absorption (e.g. distensibility and sitosterol to cholesterol ratio r = 0.628, p < 0.01), and the associations between absorption markers and arterial stiffness remained significant after adjustment on age and mean blood pressure.ConclusionsCarotid arterial stiffness was associated with markers of cholesterol metabolism, but not with serum lipid levels. Low absorption-high synthesis of cholesterol was related to increased arterial stiffness. Cholesterol metabolism seems to play a role in vascular health beyond serum lipids in type 1 diabetes.