Leptin is a
hormone secreted by adipocytes that regulates energy metabolism via peripheral action on
glucose synthesis and utilization as well as through central regulation of food intake. Patients with decreased amounts of fat in their adipose tissue (lipoatrophy) will have low
leptin levels, and hypoleptinemic states have been associated with a variety of metabolic dysfunctions. Pronounced complications of
insulin resistance,
dyslipidemia and
fatty liver are observed in patients suffering from congenital or acquired
generalized lipodystrophy while somewhat less pronounced abnormalities are associated with human immunodeficiency virus (HIV) and the use of
highly active antiretroviral therapy, the so-called
HIV-associated lipodystrophy. Previous uncontrolled open-label studies have demonstrated that physiological doses of
leptin repletion have corrected many of the metabolic derangements observed in subjects with rare fat maldistribution syndromes such as
generalized lipodystrophy. In the much more commonly encountered
HIV-associated lipodystrophy,
leptin replacement has been shown to decrease central fat mass and to improve
insulin sensitivity,
dyslipidemia, and
glucose levels. The United States Food and Drug Administration has recently granted approval for recombinant
leptin therapy for congenital and acquired
generalized lipodystrophy, however large, well-designed, placebo-controlled studies are needed to assess long-term efficacy, safety and adverse effects of
leptin replacement. In this review, we present the role of
leptin in the metabolic complications of congenital and acquired
lipodystrophy and discuss current and emerging clinical
therapeutic uses of
leptin in humans with
lipodystrophy.