Human Tissue Kallikrein Gene Transfer Induces Angiogenesis

Abstract

74 Angiogenesis therapy is emerging as a new strategy for treatment of vascular disease, not susceptible of revascularization. As kinins are implicated in vascular protection and repair, we hypothesized that targeted potentiation of kinin-nitric oxide (NO) pathway may stimulate neo-vascularization. CD1 mice were IM injected with 3.6x10 8 plaque forming units of adenovirus (Ad) harboring human tissue kallikrein (HK) or β-galactosidase (LacZ) gene under the control of cytomegalovirus enhancer/promoter (CMV). Successful transduction of injected adductor skeletal muscle was documented at mRNA and protein level. HK expression reached a peak between 3 and 7 d and then declined to become undetectable at 28 d. Contralateral muscles and liver were not transduced. Immunohistochemical identification of endothelial cell antigen factor VIII combined with blinded morphometric analysis of capillary density revealed a marked angiogenic effect in HK-transduced muscle (1013±18 vs 518±15 n cap /mm 2 in LacZ-injected muscle at 28 d, P 1 or B 2 receptors, or inhibition of NO synthase, but not by cycloxygenase inhibition. Neovascularization was associated with a transient increase in muscular blood flow as determined by laser Doppler flowmetry. HK-induced neo-vascularization was stable and functionally utilitarian, as surgical induction of hindlimb ischemia 28 d after gene tranfer was followed by accelerated hemodynamic recovery of HK-injected muscle (perfusion ratio: 0.84±0.05 vs 0.68±0.03 in LacZ-injected muscle at 14 d, P