Platelets in wound healing and regenerative medicine.

Although platelets are widely recognized as having a critical role in primary hemostasis and thrombosis, increasing experimental and clinical evidence identifies these enucleated cells as relevant modulators of other physiopathological processes including inflammation and tissue regeneration. These phenomena are mediated through the release of growth factors, cytokines, and extracellular matrix modulators that sequentially promote (i) revascularization of damaged tissue through the induction of migration, proliferation, differentiation, and stabilization of endothelial cells in new blood vessels; (ii) restoration of damaged connective tissue through migration, proliferation, and activation of fibroblasts; and (iii) proliferation and differentiation of mesenchymal stem cells into tissue-specific cell types. For these reasons, platelet-rich plasma (PRP) derivatives are used in regenerative medicine for the treatment of several clinical conditions including ulcers, burns, muscle repair, bone diseases, and tissue recovery following surgery. The benefits of PRP administration are associated with an economical advantage, taking into consideration that PRP administration does not require complex equipment or training for its execution. Moreover, due to their primary autologous origin, concerns of disease transmission or immunogenic reactions can be disregarded. Thus, platelet-enriched materials have become highly relevant in the last decade and constitute a growing focus of experimental and clinical study in the context of wound healing and tissue regeneration. However, despite the diverse applications, the efficacy of regenerative treatments using PRP is being called into question due to the lack of large controlled clinical trials and the lack of consensus regarding the PRP preparation techniques. This review describes the biological mechanisms underlying PRP's regenerative effects, the different methods of preparation and application of these biomaterials, and the controversies and future prospects related to the use of PRP in regenerative medicine.