Cardiovascular plasma lipoproteins

All of these biological roles of the steroids figure prominently in human well-being. Defects in cholesterol metabolism are major causes of cardiovascular disease. It is no wonder that steroids are a central concern in medical biochemistry. In this chapter we discuss the metabolism of these complex lipids and the plasma lipoproteins in which they and other complex lipids are transported to various tissues. 

Exchangeable apolipoproteins are a class of functionally important proteins which play a key role in plasma lipoprotein metabolism. In this capacity they have been associated with several human disorders, including hyperlipidemia and cardiovascular disease (1,2). Apolipophorin-III (apoLp-III) is a model exchangeable apolipoprotein derived from the insect Manr/Mca sexta (166 residues, Mr 18,380). ApoLp-III is a major hemolymph protein in the adult life stage and... 

Epidemiological data on cardiovascular disease, bicKhemical data on plasma lipoproteins, and nutritional data on dietary energy sources have generated information on the biochemical and dietary risk factors for cardiovascular disease. Three risk factors for cardiovascular disease can be arranged in a hierarchy ... 

A combination of bile acid sequestrants with nicotinic acid or probucol or an HMG-CoA reductase inhibitor can be used to produce synergistic effects in lowering plasma lipoprotein levels, particularly LDL. The efficacy of drug treatment was shown in a recent study in which lovas-tatin and colestipol were used to reduce cholesterol levels in men with CHD. The rate of progression of coronary lesions was decreased and that of regression increased. These changes also were associated with reduced cardiovascular abnormalities. 

Sacks, F.M. M. Katan. Randomized clinical trials on the eflPects of dietary fat and carbohydrate on plasma lipoproteins and cardiovascular disease. Am. J. Med. 2002, 113, 13S-24S. 

Estrogens are thought to exert their cardiovascular effects by acting on blood lipoproteins or by direct effects on blood vessels. In studies performed in rats, fulvestrant had no effect on plasma cholesterol levels. When administered along with estradiol, however, it blocked the cholesterol-lowering activity of estradiol (Lundeen et al. 1997). 

Sundell, I. B., Nilsson, T. K., Hallmans, G., Hellsten, G., and Dahlen, G. H., Interrelationships between plasma levels of plasminogen activator inhibitor, tissue plasminogen activator, lipoprotein (a) and established cardiovascular risk factors in a North Swedish population. Atherosclerosis (Shannon, Irel.) 80, 9-16 (1989). 

The role of the antioxidant properties of vitamins C, E, and p-carotene in the prevention of cardiovascular disease has been the focus of several recent studies. Antioxidants reduce the oxidation of low-density lipoproteins, which may play a role in the prevention of atherosclerosis. However, an inverse relationship between the intake or plasma levels of these vitamins and the incidence of coronary heart disease has been found in only a few epidemiological studies. One study showed that antioxidants lowered the level of high-density lipoprotein 2 and interfered with the effects of lipid-altering therapies given at the same time. While many groups recommend a varied diet rich in fruits and vegetables for the prevention of coronary artery disease, empirical data do not exist to recommend antioxidant supplementation for the prevention of coronary disease. 

---