Introduction to High-Density Lipoprotein, Dyslipidemia, and Coronary Heart Disease

Abstract

Alterations in plasma lipoproteins are major risk factors for coronary heart disease caused by atherosclerosis. The purpose of this chapter is to provide the reader with an overview of lipids, lipoprotein composition, lipoprotein metabolism, and lipoprotein disorders, with particular relevance to coronary heart disease risk (CHD). This chapter will then provide a framework for the reader to understand the remaining chapters in this book which have a primary focus on high-density lipoproteins (HDLs). This chapter will also allow the reader to rapidly move from a rudimentary view of lipids to a more thorough understanding of HDL, dyslipidemia, and CHD. Both increased low-density lipoprotein (LDL) cholesterol (>160 mg/dl or 4.2 mmol/l) and decreased HDL cholesterol (<40 mg/dl or 1.0 mmol/l) have been associated with an increased CHD risk. Therapies lowering LDL cholesterol and/or raising HDL cholesterol have both been associated with decreased CHD risk. Markedly elevated triglycerides (>1,000 mg/dl or 11 mmol/l) can be associated with recurrent pancreatitis. In this chapter we cover lipoprotein composition, metabolism, and briefly review the rare lipoprotein disorders cerebrotendinous xanthomatosis, phytosterolemia, abetalipoproteinemia, hypobetalipoproteinemia, and lipoprotein lipase deficiency, as well as the more common disorders dysbetalipoproteinemia, dyslipidemia, combined hyperlipidemia, lipoprotein (a) excess, and familial hypercholesterolemia. Disorders of HDL metabolism are covered in other chapters in this book. The concluding chapter will summarize where we are with CHD risk assessment, lipid management, the current state of our knowledge about HDL metabolism, and therapies for the treatment of HDL deficiency.