Non-insulin dependent diabetes and reverse cholesterol transport

Quantitative and qualitative changes are observed in high-density lipoproteins (HDL) in patients with non-insulin dependent diabetes mellitus (NIDDM), and, more generally, in states of insulin resistance combined with central obesity. Reduced levels of HDL cholesterol are observed in patients with NIDDM, this decrease being correlated with the degree of insulin resistance. Qualitative changes in HDL are characterised by an increased triglyceride content, changes in the free cholesterol-phospholipid ratio, and an increase in the number of glycosylated apolipoprotein A-I molecules, giving rise to major variations in the viscosity of HDL particles. The transport of cholesterol is reduced when HDL is glycosylated and the transfer activity of cholesterol esters is increased. There is also a reduction in the level of HDL lipid peroxidation. These abnormalities in the lipid profile cause changes in reverse cholesterol transport which may be involved in the genesis of the accelerated atherosclerosis observed in patients with NIDDM.