Purpose of review: Lipodystrophies are rare inherited and acquired disorders characterized by the selective loss of adipose tissue. Despite marked phenotypic and genotypic heterogeneity, most lipodystrophic syndromes predispose to similar metabolic complications seen in patients with obesity, such as insulin resistance, diabetes mellitus, hepatic steatosis and dyslipidemia. The purpose of this review is to highlight the current understanding of the mechanisms underlying dyslipidemia in patients with lipodystrophies.
Recent findings: Marked hypertriglyceridemia and reduced levels of high-density lipoprotein cholesterol are commonly seen, and the severity of these metabolic abnormalities seems to be related to the extent of fat loss. The precise mechanisms by which the lack of adipose tissue causes hypertriglyceridemia remain unknown. Anecdotal kinetic studies in hyperglycemic patients with lipodystrophies have revealed accelerated lipolysis and increased free fatty acid turnover, which drives hepatic triglyceride and very low-density lipoprotein synthesis. Other mechanisms may also be involved in causing dyslipidemia and ectopic triglyceride accumulation in the liver and skeletal muscles that remain to be identified.
Summary: Understanding the pathophysiology of dyslipidemia in these rare disorders of lipodystrophies may offer insights into the normal role of adipocytes in maintaining metabolic homeostasis, and its disturbances in common forms of obesity.
Division of Nutrition and Metabolic Diseases, Department of Internal Medicine and the Center for Human Nutrition, University of Texas Southwestern Medical Center at Dallas, and the Veterans Affairs North Texas Health Care System, Dallas, Texas, USA
Correspondence to Abhimanyu Garg, MD, Division of Nutrition and Metabolic Diseases, Center for Human Nutrition, UT Southwestern Medical Center at Dallas, 5323 Harry Hines Boulevard, Dallas, TX 75390-9052, USA Tel: +1 214 648 2895; fax: +1 214 648 7150; e-mail: email@example.com
Sponsorship: The authors were supported in part by National Institutes of Health grants R01-DK54387 and M01-RR00633 and by the Southwestern Medical Foundation.