High density lipoproteins and risk of coronary heart disease

Low plasma high density lipoprotein (HDL) cholesterol levels are established as a major risk factor for the development of coronary heart disease. HDLs are complex particles of different lipoprotein species and transfer proteins, the composition of which is continuously changing during their lifespan in the circulation. Results from prospective population studies fit the estimate that a 1 mg/dl increment in HDL is associated with 2-3% reduction in coronary heart disease. The potential impact of raising HDL cholesterol for preventing coronary disease is therefore important. Nevertheless, atherosclerosis is a multifactorial disease and other factors should be taken into account for the control of the onset of active coronary disease. There are some indications of a possible role of HDL not only in preventing atherosclerosis but in inhibiting arterial thrombosis, but more research is needed in this regard. Insulin resistance, hypertriglyceridaemia and low HDL are pieces of the confuse metabolic disorder called syndrome X, which also includes hyperinsulinism, glucose intolerance and hypertension. Syndrome X has been associated to increased coronary heart disease. HDL have been shown in our rabbit model of experimental atherosclerosis to be able not only of inhibiting the development and progression of the arterial lesions but also of inducing regression. More information is needed on which HDL subclasses or components have the antiatherogenic effect.