OBJECTIVE - The direct role of leptin in vascular disease remains controversial. The objective of this study was to examine the effects of leptin treatment on atherosclerosis and thrombosis in atherosclerotic-prone mice.
METHODS AND RESULTS - Sixteen-week-old, male apolipoprotein E-deficient mice were treated with injections of recombinant leptin (125 microg per day IP; n=10) or vehicle (n=10) for 4 weeks. Leptin treatment resulted in reduced epididymal fat (352+/-30.7 versus 621+/-61.5 mg; P=0.005) and fasting insulin (0.57+/-0.25 versus 1.7+/-0.22 ng/mL; P=0.014). Despite these metabolic benefits, leptin treatment resulted in an increase in atherosclerosis (8.0+/-0.95% versus 5.4+/-0.59% lesion surface coverage; P<0.05). Leptin treatment also resulted in a shortened time to occlusive thrombosis after vascular injury (21+/-2.1 versus 34.6+/-5.4 minutes; P=0.045).
CONCLUSIONS - These studies indicate that exogenous leptin promotes atherosclerosis and thrombosis and support the concept that elevations of leptin may increase the risk for cardiovascular disease.