Leptin-enhanced neointimal hyperplasia is reduced by mTOR and PI3K inhibitors.
Despite the use of the sirolimus (rapamycin) drug-eluting coronary stent, diabetics are at increased risk of developing in-stent restenosis for unclear reasons. Hyperleptinemia, which often coexists with diabetes and metabolic syndrome, is an independent risk factor for progression of coronary artery disease. It has not been determined whether elevated circulating leptin decreases the efficacy of the sirolimus drug-eluting stent in inhibiting neointimal hyperplasia, the process underlying restenosis after stenting. Here we show that leptin activates the mammalian target of rapamycin (mTOR) signaling pathway in primary murine vascular smooth muscle cells (VSMC) and stimulates VSMC proliferation in a PI3K-dependent fashion. Exogenous leptin, administered at levels comparable to those found in obese humans, promotes neointimal VSMC hyperplasia in a murine femoral artery wire injury model. Leptin significantly increases the dose of the mTOR inhibitor sirolimus that is required for effective inhibition of neointimal formation. Combination therapy with LY294002, a PI3K inhibitor, and sirolimus effectively inhibits leptin-enhanced neointimal hyperplasia. These data show that, in the setting of hyperleptinemia, higher doses of an mTOR inhibitor, or combination therapy with mTOR and PI3K inhibitors, inhibits neointimal hyperplasia after arterial injury. These studies may explain the higher rates of restenosis observed in diabetics treated with a sirolimus-eluting coronary stent and suggest a potential novel therapeutic approach for inhibiting in-stent restenosis in such patients.
Shan
Jian
J
Department of Physiology, College of Physicians and Surgeons of Columbia University, New York, NY 10032, USA.
Nguyen
Thomas B
TB
Totary-Jain
Hana
H
Dansky
Hayes
H
Marx
Steven O
SO
Marks
Andrew R
AR
D000818:Animals; D000903:Antibiotics, Antineoplastic / Q000494:pharmacology; D002478:Cells, Cultured; D005260:Female; D006801:Humans; D006965:Hyperplasia / Q000378:metabolism / Q000473:pathology*; D020738:Leptin / Q000494:pharmacology*; D051379:Mice; D008810:Mice, Inbred C57BL; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects; D032389:Myocytes, Smooth Muscle / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011494:Protein Kinases / Q000378:metabolism*; D054411:Receptors, Leptin / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D020123:Sirolimus / Q000494:pharmacology; D015607:Stents; D058570:TOR Serine-Threonine Kinases; D017539:Tunica Intima / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology*
D000903:Antibiotics, Antineoplastic; D020738:Leptin; D020928:Mitogen-Activated Protein Kinases; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011494:Protein Kinases; D054411:Receptors, Leptin; D020123:Sirolimus; D058570:TOR Serine-Threonine Kinases; C546842:MTOR protein, human; C546843:mTOR protein, mouse