Diabetes, lipoproteins, and atherosclerosis.

Certain lipoproteins are deemed to be atherogenic because (a) they are found in plasmas of patients with various dyslipoproteinemias who also have atherosclerosis, (b) they appear in plasmas and arterial walls of animals during the experimental induction of atherosclerosis, and (c) they convert cultured macrophages and arterial smooth muscle cells into lipid-laden foam cells such as are found in atherosclerotic lesions. These lipoproteins are low-density lipoproteins (LDL), very low density lipoproteins (VLDL), and the alpha-VLDL of hypertriglyceridemic patients. Low levels or the absence of high-density lipoproteins (HDL) in patients is also associated with atherosclerosis. Poorly controlled diabetics may have higher levels of VLDL and/or LDL and lower levels of HDL than are found in well-controlled diabetics. These quantitative changes place poorly controlled patients into higher coronary risk categories. Several qualitative alterations of lipoprotein also may be present that may make them more atherogenic, among these, glycosylation of apoprotein could be very important.