The Effect of Long-Term Cryopreservation on the Properties and Functionality of Platelet-Rich Plasma.

Platelet-Rich Plasma (PRP) is a biological treatment widely used in regenerative medicine for its restorative capacity. Although PRP is typically applied at the time of obtention, long-term storage and preservation could enhance its versatility and clinical applications. The objective of this study was to evaluate the effect of long-term freezing on PRP. For that, PRP and Platelet Lysates (PL) were collected and preserved at -20 °C and -80 °C for 6 and 12 months. The parameters analyzed included platelet count and size, fibrinogen levels, platelet activation percentage, growth factor (GF) levels, and bioactivity on cultured dermal fibroblasts. No significant changes in platelet count were found; however, variations in platelet size were observed. Platelets stored at -20 °C and -80 °C showed structural changes and increased activation over time, including membrane roughness and possible aggregation. GF analysis revealed a reduction in platelet-derived growth factors (PDGF-AB and VEGF), while extraplatelet factors like IGF-1 remained stable. Fibroblast cultures showed comparable cell viability when exposed to fresh and cryopreserved PRP and PL samples. These findings suggest that cryopreserving PRP at -20 °C or -80 °C for up to 12 months is a feasible approach for retaining its therapeutic potential, supporting its use in biobanking, and expanding clinical accessibility.