title: Hyperhomocysteinemia impairs angiogenesis in response to hindlimb ischemia.
abstract: Hyperhomocysteinemia (HH) is an independent risk factor for atherosclerosis, including peripheral arterial occlusive disease (PAOD). Because angiogenesis and collateral vessel formation are important self-salvage mechanisms for ischemic PAOD, we examined whether HH modulates angiogenesis in vivo in a rat model of hindlimb ischemia. Rats were divided into 3 groups: the control group was given tap water, the HH group was given water containing L-methionine (1 g x kg(-1) x d(-1)), and the HH+L-arg group was given water containing methionine (1 g x kg(-1) x d(-1)) and l-arginine (2.25 vol%). At day 14 of the dietary modifications, the left femoral artery and vein were excised, and the extent of angiogenesis and collateral vessels in the ischemic limb were examined for 4 weeks. Plasma homocysteine levels significantly increased (P:<0.001), and plasma and tissue contents of nitrite+nitrate as well as tissue cGMP levels significantly decreased in the HH group compared with the control group (P:<0.01). Laser Doppler blood flowmetry (LDBF) revealed a significant decrease in the ischemic/normal limb LDBF ratio in the HH group at days 7, 14, 21, and 28 (P:<0.01 versus control). Angiography revealed a significant decrease in the angiographic score in the HH group at day 14 (P:<0.001 versus control). Immunohistochemistry of ischemic tissue sections showed a significant reduction in the capillary density in the HH group (P:<0. 001 versus control). Oral l-arginine supplementation in rats with HH (HH+L-arg) restored the decreased plasma and tissue nitrite+nitrate and cGMP contents (P:<0.05) as well as angiogenesis, as assessed by LDBF (P:<0.05 versus HH), angiographic score (P:<0.01 versus HH), and capillary density (P:<0.001 versus HH). In summary, HH impaired ischemia-induced angiogenesis and collateral vessel formation in a rat model of hindlimb ischemia in vivo. The mechanism of the HH-induced impairment of angiogenesis might be mediated in part by a reduced bioactivity of endogenous NO in the HH state.
authors: Cardiovascular Research Institute and Department of Internal Medicine III, Kurume University School of Medicine, Kurume, Japan.
authors: J
authors: J
authors: Duan
authors: T
authors: T
authors: Murohara
authors: H
authors: H
authors: Ikeda
authors: K
authors: K
authors: Sasaki
authors: S
authors: S
authors: Shintani
authors: T
authors: T
authors: Akita
authors: T
authors: T
authors: Shimada
authors: T
authors: T
authors: Imaizumi
mesh_terms: D000792:Angiography; D000818:Animals; D001120:Arginine / Q000627:therapeutic use; D001794:Blood Pressure; D001835:Body Weight; D003097:Collateral Circulation; D006152:Cyclic GMP / Q000378:metabolism; D004195:Disease Models, Animal; D006339:Heart Rate; D006614:Hindlimb / Q000098:blood supply*; D006710:Homocysteine / Q000097:blood; D020138:Hyperhomocysteinemia / Q000150:complications / Q000503:physiopathology*; D007150:Immunohistochemistry; D007511:Ischemia / Q000097:blood / Q000150:complications* / Q000188:drug therapy; D017078:Laser-Doppler Flowmetry; D018482:Muscle, Skeletal / Q000378:metabolism; D018919:Neovascularization, Physiologic; D009566:Nitrates / Q000097:blood; D009573:Nitrites / Q000097:blood; D051381:Rats; D012039:Regional Blood Flow; D013997:Time Factors
chemical_list: D009566:Nitrates; D009573:Nitrites; D006710:Homocysteine; D001120:Arginine; D006152:Cyclic GMP