Nox2-containing NADPH oxidase deficiency confers protection from hindlimb ischemia in conditions of increased oxidative stress.
OBJECTIVE
Because Nox2-containing NADPH oxidase is a major source of ROS in the vasculature, we investigated its potential role for the modulation of ischemia-induced neovascularization in conditions of increased oxidative stress.


RESULTS
To mimic a clinical situation of increased oxidative stress, mice were exposed to cigarette smoke before and after the surgical induction of hindlimb ischemia. Nox2 expression and oxidative stress in ischemic tissues were significantly increased in wild-type mice, but not in mice deficient for the Nox2-containing NADPH oxidase (Nox2(-/-)). Nox2(-/-) mice demonstrated faster blood flow recovery, increased capillary density in ischemic muscles, and improved endothelial progenitor cell functional activities compared to Nox2(+/+) mice. In addition, Nox2 deficiency was associated with increased antioxidant and nitrite concentrations in plasma, together with a preserved expression of eNOS in ischemic tissues. In vitro, Nox2(-/-) endothelial cells exhibit resistance against superoxide induction and improved VEGF-dependent angiogenic activities compared to Nox2(+/+) endothelial cells. Importantly, the beneficial effects of Nox2 deficiency on neovascularization in vitro and in vivo were lost after treatment with the NO inhibitor L-NAME.


CONCLUSIONS
Nox2-containing NADPH oxidase deficiency protects against ischemia in conditions of increased oxidative stress. The mechanism involves improved neovascularization through a reduction of ROS formation, preserved activation of the VEGF/NO angiogenic pathway, and improved functional activities of endothelial progenitor cells.
Haddad
Paola
P
Department of Cardiovascular Research, Centre Hospitalier de l'Université de Montréal, 1560 Sherbrooke Est, Montreal, Que, Canada.
Dussault
Sylvie
S
Groleau
Jessika
J
Turgeon
Julie
J
Michaud
Sophie-Elise
SE
Ménard
Catherine
C
Perez
Gemma
G
Maingrette
Fritz
F
Rivard
Alain
A
D000818:Animals; D042783:Endothelial Cells / Q000502:physiology; D006614:Hindlimb / Q000098:blood supply*; D007511:Ischemia / Q000378:metabolism / Q000517:prevention & control*; D008562:Membrane Glycoproteins / Q000172:deficiency / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D000074662:NADPH Oxidase 2; D019255:NADPH Oxidases / Q000172:deficiency / Q000502:physiology*; D018919:Neovascularization, Physiologic; D009569:Nitric Oxide / Q000378:metabolism; D018384:Oxidative Stress; D017382:Reactive Oxygen Species / Q000378:metabolism; D012906:Smoke / Q000009:adverse effects; D013234:Stem Cells / Q000502:physiology; D014026:Nicotiana / Q000009:adverse effects
D008562:Membrane Glycoproteins; D017382:Reactive Oxygen Species; D012906:Smoke; D009569:Nitric Oxide; C488842:Cybb protein, mouse; D000074662:NADPH Oxidase 2; D019255:NADPH Oxidases