[Anomalies of lipid metabolism in diabetes mellitus]

Atheroma is by far the most common cause of mortality in diabetic patients (66 to 75% of deaths). Several physiopathological mechanisms are suspected to account for the greater frequency and severity of atheroma in diabetes. Among these, lipid abnormalities hold first rank and include not only quantitative but also qualitative abnormalities of lipoproteins altering their kinetics and bindings to membrane receptors. The main quantitative abnormalities are an increase of triglycerides and very low density lipoproteins (VLDL) and a fall in high density lipoproteins (HDL) and their HDL2 subfraction. Qualitative abnormalities include non-enzymatic glucosylation of apoproteins, changes in lipoprotein size and increase in their triglyceride content, and excessive oxidation of low density lipoproteins (LDL). Both quantitative and qualitative abnormalities of lipoproteins are present in non-insulin-dependent diabetes, whereas only qualitative abnormalities are observed, as a rule, in treated insulin-dependent diabetes. The physiopathology of lipid metabolism disorders is complex, possibly multifactorial and still imperfectly known. However, such factors as modification of insulin status, hyperglycaemia and obesity frequently associated with diabetes, are thought to be involved.