Healing modulation induced by freeze-dried platelet-rich plasma and micronized allogenic dermis in a diabetic wound model

The incidence and prevalence of chronic and diabetic wounds are increasing and clinical treatments to tackle these epidemics are still insufficient. In this study, we tested the ability of freeze-dried platelet-rich plasma (PRP) and an allogenic micronized acellular dermal matrix alone and in combination to modulate diabetic wound healing. Therapeutic materials were applied to 1.0 cm(2) excisional wounds on genetically diabetic (db/db) mice. Wound-healing kinetics and new tissue formation were studied at 9 and 21 days posttreatment. Quantitative immunohistochemistry was used to study vascularity and cellular proliferation (days 9 and 21), and collagen deposition was evaluated 21 days postwounding. In vitro, micronized allogenic dermis, when combined with PRP, absorbed nearly 50% of original platelet-derived growth factor, transforming growth factor-beta, vascular endothelial growth factor, and epidermal growth factor from platelets and stimulated fibroblast proliferation. In vivo, micronized dermis increased the formation of vascularized wound tissue by day 9. Freeze-dried PRP alone or in combination with micronized dermis increased wound tissue revascularization and proliferation compared with spontaneous healing. The increase in cell proliferation persisted until day 21 only when freeze-dried PRP was used in combination with micronized dermis. These results indicate that micronized allogenic dermis may be used to provide a dermal matrix to stimulate tissue formation and the combination with PRP may confer additional beneficial growth factors to chronic or diabetic wounds.