Inhibition of endogenous leptin protects mice from arterial and venous thrombosis.
OBJECTIVE
Human obesity is associated with an increased risk for arterial and venous thrombosis and with elevated levels of leptin in the blood. Leptin administration promotes arterial thrombosis in mice, and leptin-deficient ob/ob mice have an attenuated thrombotic response to injury. Thus, endogenous leptin may regulate arterial and venous thrombosis in vivo. Experiments were performed to test this hypothesis.


RESULTS
A leptin-neutralizing antibody was administered intravenously into wild-type mice 15 minutes before carotid artery injury with ferric chloride. The antibody-treated mice demonstrated prolonged times to thrombotic occlusion and formed unstable, embolizing thrombi. Thus, inhibiting leptin converted the thrombotic phenotype of wild-type mice into one that closely resembled that of ob/ob mice. The effect of leptin inhibition on venous thrombosis and pulmonary embolism was also investigated. Injection of a mixture of collagen and epinephrine into the jugular vein induced fatal pulmonary embolism in >90% of the control wild-type mice but in <40% of their antibody-treated counterparts. Histological analysis revealed that the antibody significantly reduced the number of occlusive thrombi in the pulmonary vessels.


CONCLUSIONS
Inhibition of circulating leptin protects against arterial and venous thrombosis in mice and possibly in hyperleptinemic obese individuals.
The Scripps Research Institute, Department of Cell Biology, Division of Vascular Biology, La Jolla, Calif 92037, USA.
Stavros
S
Konstantinides
Katrin
K
Schäfer
Jaap G
JG
Neels
Claudia
C
Dellas
David J
DJ
Loskutoff
D000818:Animals; D019138:Antibodies, Blocking / Q000378:metabolism / Q000494:pharmacology; D001157:Arterial Occlusive Diseases / Q000139:chemically induced / Q000517:prevention & control; D002712:Chlorides; D005290:Ferric Compounds / Q000008:administration & dosage / Q000009:adverse effects; D020738:Leptin / Q000037:antagonists & inhibitors* / Q000276:immunology / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D011956:Receptors, Cell Surface / Q000378:metabolism; D054411:Receptors, Leptin; D020246:Venous Thrombosis / Q000139:chemically induced / Q000517:prevention & control
D019138:Antibodies, Blocking; D002712:Chlorides; D005290:Ferric Compounds; C515448:LEPR protein, human; D020738:Leptin; D011956:Receptors, Cell Surface; D054411:Receptors, Leptin; C515447:leptin receptor, mouse; C024555:ferric chloride