Abstract 13974: Enhanced Vascularization by Controlled Release of Platelet-Rich Plasma impregnated in gelatin hydrogels for Critical Limb Ischemia in Rats
Background: Single angiogenic factor is unable to establish stable vascular networks. A combination of growth factors synergistically induces angiogenesis and long-lasting functional vessels. Platelet-rich plasma(PRP)contains numerous growth factors, has an obvious effect on wound healing, and has strong angiogenetic properties. However, it is limited by the short half-life period during which it can promote angiogenesis. A new drug delivery system using biodegradable gelatin hydrogel is designed to control the release of PRP. The purpose of this study was to verify the effectiveness of the controlled release of PRP in encouraging angiogenesis for critical limb ischemia.
Methods: PRP was prepared from whole blood in inbred male wister rats. Thirty-two rats underwent excision of the left femoral artery and its branches to create critical limb ischemia. The rats were randomized into 4 groups (n=8 each): no treatment, intramuscular injection of platelet-poor plasma (PPP), platelet-rich plasma (PRP) only, or a combination of PRP+gelatin hydrogel (PRP+Gel). Four weeks after the treatment angiogenesis was evaluated by a micro-angiogram, laser doppler, and immuno-histology.
Results: The resultant number of platelets was higher in the PRP group than in group PPP (p<0.01). The concentrations of PDGF-BB (10272.2±888.9 vs 118.2±71.3 pg/ml), VEGF (77.5±50.4 vs 0 pg/ml), and TGF-β1 (132.9±24.6 vs 1.82±0.4ng/ml) were significantly higher in the PRP group than those in the PPP group, respectively (p<0.05). Although injected PRP improved tissue blood flow (82.7±6.2%) compared with no treatment or PPP (69.6±12.2 or 72.2±11.8%, p<0.05), the improvement in the PRP+Gel group was significantly better (95.1±8.0%, p<0.01) than PRP only. Vascular density in PRP+Gel was significantly higher than no treatment, PPP and PRP groups (77.7±17.3 vs 31.1±9.2, 33.7±4.9, 50.8±12.2/mm2, respectively p<0.01). Capillary density also significantly increased in the PRP+Gel group when compared to the no treatment, PPP and PRP groups (p<0.05).
Conclusions: Controlled Release PRP system is markedly effective in encouraging angiogenesis for critical limb ischemia. The combination of PRP and biodegradable gelatin hydrogel may maintain growth factors to induce angiogenesis.
- © 2010 by American Heart Association, Inc.