[Disorders of lipid metabolism in diabetes mellitus]

Diabetes mellitus is the most frequent endogenous cause of fat metabolism-disorder. In diabetics the risk for arteriosclerosis is significantly higher and the clinical significance of hyperlipidemia should be estimated more serious as in non-diabetics. The predominant abnormality of fat metabolism in diabetes is hypertriglyceridemia due to an increase of triglyceride-carrying lipoproteins, the chylomicrons and the very-low-density lipoproteins. In type I-diabetics the decisive pathogenetic factor for hypertriglyceridemia is the impaired degradation of VLDL and the reduced chylomicron-clearance, caused by decreased activity of the lipoproteinlipase. In ketoacidosis there is an additional increase in hepatic VLDL-triglyceride-production due to increased lipolysis with elevated free-fatty-acid flux. Total cholesterol in type I-diabetics is only significantly elevated when metabolic control is poor, low-density lipoprotein (LDL-)-cholesterol-levels can be increased and high-density lipoprotein (HDL-)cholesterol decreased in dependence on the metabolic control. In type II-diabetics the decisive pathogenetic factor for hypertriglyceridemia is increased VLDL-triglyceride-synthesis in the liver especially due to augmented free-fatty-acid flux. Additionally the activity of the lipoproteinlipase can be reduced. Usually in non-insulin-dependent diabetics LDL-cholesterol-levels can be seen elevated and HDL-cholesterol-concentration decreased in correlation with the metabolic control. Primary hyperlipoproteinemia appears frequently in diabetics, but this can be explained by the association with obesity in type II-diabetics.