L-Arginine and L-NAME have no effects on the reendothelialization process after arterial balloon injury

Objective: Growth regulatory properties of nitric oxide (NO) in cultured en dothelial cells is controversial. The aim of our study was to investigate t he effect of l-arginine, the endogenous NO precursor, and L-NAME, an inhibi tor of NO synthase on the reendothelialization process after angioplasty. M ethods: Fifty-five New Zealand White rabbits underwent denudation of the le ft iliac artery. After injury the rabbits were randomized in three groups: L-arginine 2.25% (l-arginine, n=19); N-G-nitro-L-arginine methyl ester 15 m g/kg/day (L-NAME, n=19); and placebo (controls, n=17). Treatment was solubi lized in drinking water. Reendothelialization was evaluated at 4 weeks by m acroscopic evaluation of Evens blue staining and endothelial-specific immun ostaining (CD-31) on cross sections. Intimal hyperplasia was evaluated by m orphometric analysis. Results: Despite a significant increase in plasma arg inine (P=0.001) and a reduction in intimal hyperplasia (P=0.003) with L-arg inine, neither agent had a significant effect on reendothelialization at 4 weeks (controls=36+/-4%, L-arginine=43+/-3%, L-NAME=33+/-4%; NS). Conclusio n: These results suggest that, in spite of previously demonstrated effects on neointimal hyperplasia, the NO pathway does not influence the regrowth o f macrovascular endothelial cells in vivo. (C) 1999 Elsevier Science B.V. A ll rights reserved.