Endothelial nitric oxide synthase lies downstream from angiotensin II-induced angiogenesis in ischemic hindlimb.
We assessed the role of angiotensin (Ang) II in ischemia-induced angiogenesis and analyzed the molecular pathways involved in such an effect. Ischemia was produced by unilateral artery femoral occlusion in control, in valsartan-treated (Ang II receptor type I antagonist, 20 mg/kg per day), in Ang II-treated (5 ng/kg per min), and in Ang II and valsartan-treated rats. After 28 days, angiogenesis was assessed by microangiography and capillary density measurement in hindlimbs. The ischemic/nonischemic leg ratio for angiographic score and capillary number increased by 2.6- and 2-fold, respectively, in Ang II-treated rats compared with controls (P<0.01). This was associated with an increase in vascular endothelial growth factor (VEGF; 1.6-fold) and endothelial NO synthase (eNOS; 1.8-fold) protein content within the ischemic leg, assessed by Western blot. Angiotensin type 1 receptor blockade and administration of VEGF neutralizing antibody (2.5 microg IP, twice a week) in Ang II-treated rats completely prevented such Ang II angiogenic effects. The key role of eNOS was then emphasized by using mice deficient in gene encoding for eNOS. In wild-type mice, Ang II (0.3 mg/kg per min) treatment increased by 1.7- and 1.6-fold the ischemic/nonischemic leg for angiographic score and blood perfusion (assessed by laser Doppler perfusion imaging) ratios, respectively (P<0.01). Conversely, no significant changes were observed in Ang II-treated mice deficient in gene encoding for eNOS. Subhypertensive dose of Ang II enhanced angiogenesis associated with tissue ischemia through angiotensin type 1 receptor activation that involved the VEGF/eNOS-dependent pathway.
Tamarat
Radia
R
INSERM U541, Hôpital Lariboisière, IFR Circulation-Paris 7, Université Paris 7-Denis Diderot, Paris, France.
Silvestre
Jean-Sébastien
JS
Kubis
Nathalie
N
Benessiano
Joelle
J
Duriez
Micheline
M
deGasparo
Marc
M
Henrion
Daniel
D
Levy
Bernard I
BI
D000804:Angiotensin II / Q000494:pharmacology*; D000818:Animals; D002196:Capillaries / Q000187:drug effects / Q000378:metabolism; D016228:Endothelial Growth Factors / Q000378:metabolism; D005838:Genotype; D006614:Hindlimb / Q000098:blood supply*; D007511:Ischemia / Q000503:physiopathology; D017078:Laser-Doppler Flowmetry; D008222:Lymphokines / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D018919:Neovascularization, Physiologic / Q000187:drug effects*; D019001:Nitric Oxide Synthase / Q000235:genetics / Q000378:metabolism*; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; D051381:Rats; D017208:Rats, Wistar; D044140:Receptor, Angiotensin, Type 1; D011945:Receptors, Angiotensin / Q000502:physiology; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors
D016228:Endothelial Growth Factors; D008222:Lymphokines; D044140:Receptor, Angiotensin, Type 1; D011945:Receptors, Angiotensin; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; D000804:Angiotensin II; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; C496315:Nos3 protein, mouse; C496316:Nos3 protein, rat