Summary

Development of a new method based on water absorption to obtain a Platelet-rich plasma (PRP) enriched in both platelet and extraplatelet molecules which enhance cell proliferation, mantains cellular migration capacity and reduce pro-inflammatory cytokines comparing to a standard PRP.

Abstract

Platelet-rich plasma (PRP) is an autologous biologic product used in several fields of medicine for tissue repair due to the regenerative capacity of the biomolecules of its formulation. PRP consists of a plasma with a platelet concentration higher than basal levels but with basal levels of any biomolecules present out of the platelets. Plasma contains extraplatelet biomolecules known to enhance its regenerative properties. Therefore, a PRP containing not only a higher concentration of platelets but also a higher concentration of extraplatelet biomolecules could have a stronger regenerative performance than a standard PRP. Considering this, the aim of this work is to develop a new method to obtain PRP enriched in both platelet and extraplatelet molecules. The method is based on the absorption of the water of the plasma using hydroxyethyl acrylamide (HEAA)-based hydrogels. A plasma fraction obtained from blood, containing the basal levels of platelets and proteins, was placed in contact with the HEAA hydrogel powder to absorb half the volume of the water. The resulting plasma was characterized, and its bioactivity was analyzed in vitro. The novel PRP (nPRP) showed a platelet concentration and platelet derived growth factor (PDGF) levels similar to the standard PRP (sPRP), but the concentration of the extraplatelet growth factors IGF-1 (p < 0.0001) and HGF (p < 0.001) were significantly increased. Additionally, the cells exposed to the nPRP showed increased cell viability than those exposed to a sPRP in human dermal fibroblasts (NHDF) (p < 0.001) and primary chondrocytes (p < 0.01). Regarding to cell migration capacity, it was found that the process is platelet-dependent, achieving similar wound healing closure percentage between sPRP and nPRP. Finally, anti-inflammatory effect of both formulations was evaluated. For this, an inflammatory environment was produced using LPS in previously differentiated M1 macrophages. When cytokine levels were measured by ELISA after nPRP administration, a significant decrease of pro-inflammatory IL-1b (p < 0.0001), IL-6 (p < 0.0001) and TNF-α (p < 0.001) was observed. In conclusion, this novel absorption-based method produces a PRP with novel characteristics compared to the standard PRPs, with promising in vitro results that could potentially trigger improved tissue regeneration capacity.