The triglyceride connection in atherosclerosis.

OBJECTIVE: To examine the proposed mechanism of triglyceride-induced atherogenesis, to address the controversy surrounding serum triglycerides as a coronary heart disease (CHD) risk factor, and to recommend an appropriate therapeutic approach to hypertriglyceridemia. DATA SOURCES: Studies, review articles, and editorials published since 1976. A MEDLINE search of English-language literature was conducted using the terms triglyceride and hypertriglyceridemia. STUDY SELECTION: Studies, review articles, and editorials were selected for detailed review if they addressed the pathogenesis of triglyceride-induced atherosclerosis, the controversy associated with elevated serum triglyceride as a CHD risk factor, and hypertriglyceridemia treatment options. DATA EXTRACTION: Data were reviewed that described the atherogenicity of chylomicron and very low-density lipoprotein (VLDL) remnants, the inverse relationship that exists between high-density lipoprotein (HDL) and serum triglyceride, the hypertriglyceridemia treatment controversy, and the treatment options of diet, exercise, weight control, alcohol restriction, and medication. DATA SYNTHESIS: Hypertriglyceridemia is a well-known risk factor for pancreatitis. However, its role in atherogenesis is less well defined. Several proposed connections appear to exist between hypertriglyceridemia and atherosclerosis, including the inverse correlation between triglycerides and HDL, the presumed atherogenicity of triglyceride-rich lipoprotein remnant particles, the potential resultant increase in the serum concentration and atherogenicity of low-density lipoprotein (LDL), and the proposed interaction between serum triglyceride and the fibrinolytic/coagulation system. Clinical trials addressing this issue offer mixed results that are subject to interpretation. Diet, exercise, weight control, alcohol restriction, and certain lipid-lowering medications are effective at reducing serum triglyceride.
CONCLUSIONS: Hypertriglyceridemia is a theoretical risk factor for CHD because of the increased production of atherogenic chylomicron and VLDL remnants, the inverse relationship present between serum triglyceride and HDL, the possible resultant increase in LDL attributable to remnant-reduced hepatic LDL-receptors as well as the formation of more dense and, therefore, more atherogenic LDL, and to the interaction between serum triglyceride and the fibrinolytic/coagulation system. However, most clinical trials that have found hypertriglyceridemia to be a risk factor for CHD do not include other CHD risk factors in their analyses. Therapeutic intervention to lower serum triglyceride with diet, exercise, and/or drugs is definitely recommended in the treatment and/or prevention of pancreatitis; however, the role of triglyceride-lowering to reduce CHD risk remains controversial.