Should low high-density lipoprotein cholesterol (HDL-C) be treated?
The first observations linking a low serum level of HDL-C to increased risk for cardiovascular disease were made over 50 years ago. High serum levels of HDL-C appear to protect against the development of atherosclerotic disease, while low serum levels of this lipoprotein are among the most important predictors of atherosclerotic disease in both men and women and people of all racial and ethnic groups throughout the world. It has long been assumed that therapeutic interventions targeted at raising HDL-C levels would lower risk for such cardiovascular events as myocardial infarction, ischemic stroke, and death. Even after five decades of intensive investigation, evidence to support this assumption has been fleeting. A number of post hoc analyses of randomized controlled trials and meta-analyses suggest that HDL-C raising, particularly when coupled with aggressive LDL-C reduction, impacts risk for cardiovascular events and rates of progression of atherosclerotic disease. Unfortunately, four recent prospective trials performed with the intent of testing the "HDL hypothesis" (ILLUMINATE, dal-OUTCOMES, AIM-HIGH, and HPS2-THRIVE) failed to meet their primary composite endpoints. These results have lead many clinicians and investigators to question the validity of the assumption that HDL-C raising reduces risk for cardiovascular events. Additional trials with other drugs are underway. In the meantime, HDL-C cannot be considered a target of therapy. Given the complexity of the HDL proteome and lipidome, there is biological plausibility for how HDL particles might exert atheroprotection. We explore the evidence supporting the inverse relationship between HDL-C and cardiovascular disease risk, documented mechanisms by which HDL particles may exert atheroprotection, and the findings either supporting or negating specific therapeutic interventions in patients afflicted with low HDL-C.
CGH Medical Center, Sterling, IL 61081, USA; University of Illinois School of Medicine, Peoria, IL, USA. Electronic address: peter.toth@cghmc.com.
Peter P
PP
Toth
Department of Internal Medicine and Cardiological Rehabilitation, Medical University of Lodz, Lodz, Poland. Electronic address: mbarylski3@wp.pl.
Marcin
M
Barylski
Biomedical Department of Internal Medicine and Medical Specialties University of Palermo, Palermo, Italy. Electronic address: draggana.nikolic@gmail.com.
Dragana
D
Nikolic
Biomedical Department of Internal Medicine and Medical Specialties University of Palermo, Palermo, Italy; Euro-Mediterranean Institute of Science and Technology, Palermo, Italy. Electronic address: manfredi.rizzo@unipa.it.
Manfredi
M
Rizzo
Biomedical Department of Internal Medicine and Medical Specialties University of Palermo, Palermo, Italy. Electronic address: giuseppe.montalto@unipa.it.
Giuseppe
G
Montalto
Nephrology and Hypertension, Medical University of Lodz, Zeromskiego 113, 90-549 Lodz, Poland. Electronic address: maciejbanach@aol.co.uk.
Maciej
M
Banach
D002318:Cardiovascular Diseases / Q000097:blood / Q000453:epidemiology / Q000517:prevention & control*; D008076:Cholesterol, HDL / Q000097:blood* / Q000502:physiology; D050171:Dyslipidemias / Q000097:blood* / Q000188:drug therapy* / Q000453:epidemiology; D005260:Female; D058607:Fibric Acids / Q000627:therapeutic use; D006801:Humans; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors / Q000627:therapeutic use; D008297:Male; D009525:Niacin / Q000627:therapeutic use; D012307:Risk Factors; D045162:Thiazolidinediones / Q000627:therapeutic use
D008076:Cholesterol, HDL; D058607:Fibric Acids; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors; D045162:Thiazolidinediones; D009525:Niacin
coronary artery disease; fibrate; high-density lipoproteins; low-density lipoproteins; niacin; reverse cholesterol transport; statin; thiazolidinedione