Adenovirus-mediated
kallikrein delivery has been shown to promote blood vessel growth in the limb under both ischemic and normoperfused conditions. Here we investigated whether a continuous supply of
kallikrein and
kinin peptide can induce neovascularization in a rat model of hindlimb
ischemia. Rats underwent femoral artery
ligation and localized injection of
tissue kallikrein,
bradykinin or B1 receptor agonist, followed by infusion of
proteins by osmotic minipump. Regional blood flow was monitored weekly by
laser Doppler perfusion imaging. Three weeks after surgery, rats receiving
kallikrein and
kinins showed a significant increase in the perfusion ratio of ischemic vs. normoperfused limb compared to control rats. Similarly, a
microsphere assay showed that
kallikrein and
kinins significantly increased regional blood flow without altering blood pressure. Moreover,
kallikrein and
kinins significantly augmented capillary and arteriole densities, as quantified by immunostaining with CD-31 and smooth muscle
alpha-actin. Both
tissue kallikrein and
bradykinin increased
hemoglobin content in
Matrigel implants in mice, providing further evidence of the angiogenic properties.
Kinins, when delivered subcutaneously via
Matrigel in rats, also increased regional perfusion. This is the first demonstration that local application of
tissue kallikrein protein or
kinin peptide has therapeutic value in the treatment of ischemic disease by promoting neovascularization.