Endothelial nitric oxide synthase affects both early and late collateral arterial adaptation and blood flow recovery after induction of hind limb ischemia in mice

Abstract

Objective The goals of this study were to determine if endothelial nitric oxide synthase (eNOS) affects both early and late collateral arterial adaptation and blood flow recovery after severe limb ischemia, and to determine if eNOS-derived NO was necessary for recruitment of CXCR4+ VEGFR1+ hemangiocytes to the site of ischemia. Methods and Results Two studies were carried out. In the first study, hindlimb ischemia was induced by unilateral femoral artery excision in 3 groups: C57Bl6 (wild type), eNOS-/-, and C57Bl/6 mice treated with L-NAME from 1 day prior to excision through day 3 after excision (early L-NAME group). These 3 groups were studied on the 3rd day after induction of ischemia. In the second study, hindlimb ischemia was induced in 2 groups: C57Bl/6 mice (wild type) and C57Bl/6 mice treated with L-NAME from the 3rd through the 28th day after induction of ischemia. These 2 groups were studied on the 28th day after induction of ischemia. Dependent variables included hindlimb perfusion, collateral artery diameter, and the number and location of hemangiocytes within the ischemic hindlimb. Results In the first study, the eNOS-/- and early L-NAME treatment groups developed toe gangrene by the 2nd day of ischemia. These groups demonstrated less blood flow recovery and smaller collateral artery diameter than the wild type group. Hemangiocytes were present within the adventitia of collateral arteries in the wild type group, but were only sparsely present, in a random pattern, in the eNOS-/- and early L-NAME treatment groups. In the second study, the late L-NAME group showed less blood flow recovery and smaller collateral artery diameter on the 28th day of ischemia than the wild type group. Hemangiocytes were present in a peri-capillary distribution in the wild type group, but present only sparsely in the late L-NAME treatment group. Conclusion eNOS-derived NO is necessary for both the early (day 3) and late (day 28) adaptive responses to hindlimb ischemia. NO is necessary for normal hemangiocyte recruitment to the ischemic tissue.

Fluid shear stress upregulates placental growth factor in the vessel wall via NADPH oxidase 4

“…Both eNOS and NO production are increased during arteriogenesis, and blocking NO production with L-NAME or eNOS knockout inhibits collateral growth in several models of arteriogenesis (27,33,36,60). We verified that the high-FSS A: high, but not normal, FSS significantly increased nitrate/nitrite levels immediately after shear exposure compared with static control (n ϭ 5).…”

Tetrahydrobiopterin, L-Arginine and Vitamin C Act Synergistically to Decrease Oxidative Stress, Increase Nitric Oxide and Improve Blood Flow after Induction of Hindlimb Ischemia in the Rat

“…Rats provided with two (BH4 + L-arginine) or three (BH4 + L-arginine + vitamin C) supplements showed significantly greater recovery of foot perfusion than rats fed normal chow or rats given a single dietary supplement. This difference was evident at the later phase of recovery, on d 21, 28 or 42 after induction of ischemia, which was also the time of maximal collateral artery wall remodeling (20). A similar pattern was noted for collateral artery angioscores determined on d 42 after induction of ischemia.…”

Beneficial effects of ginsenoside-Rg1 on ischemia-induced angiogenesis in diabetic mice

“…Previous study found that activation of eNOS is impaired in diabetic bone marrow, resulting in the deficiency of endothelial progenitor cells mobilization [33]. In addition, observations indicated that eNOS-derived NO is requisite for acute adaptation to severe ischemia to prevent tissue necrosis and for sustained arteriogenesis [34]. Leung et al [15] have shown that Rg1 can increase phosphorylation and the activities of PI3K, Akt, and eNOS, leading to increased NO production in HUVECs.…”