Systematic Review—The Potential Implications of Different Platelet-Rich Plasma (PRP) Concentrations in Regenerative Medicine for Tissue Repair

Abstract

The number of studies evaluating platelet-rich plasma (PRP) concentration has substantially grown in the last fifteen years. A systematic review on this field has been realized by evaluating in the identified studies the in vitro PRP concentration—also analyzing the platelet amount—and the in vivo PRP effects in tissue regeneration compared to any control. The protocol has been developed in agreement with the Preferred Reporting for Items for Systematic Reviews and Meta-Analyses-Protocols (PRISMA-P) guidelines. Multistep research of the PubMed, MEDLINE, Embase, PreMEDLINE, Ebase, CINAHL, PsycINFO, Clinicaltrials.gov, Scopus database and Cochrane databases has permitted to identify articles on different concentrations of PRP in vitro and related in vivo impact for tissue repair. Of the 965 articles initially identified, 30 articles focusing on PRP concentration have been selected and, consequently, only 15 articles have been analyzed. In total, 40% (n = 6) of the studies were related to the fixed PRP Concentration Group used a fixed PRP concentration and altered the platelet concentration by adding the different volumes of the PRP (lysate) to the culture. This technique led to a substantial decrease in nutrition available at higher concentrations. Sixty percent (n = 9) of the studies were related to the fixed PRP Volume Group that used a fixed PRP-to-media ratio (Vol/Vol) throughout the experiment and altered the concentration within the PRP volume. For both groups, when the volume of medium (nutrition) decreases, a lower rate of cell proliferation is observed. A PRP concentration of 1.0 × 106 plt/μL, appears to be optimal thanks to the constant and plentiful capillary nutrition supply and rapid diffusion of growth factors that happen in vivo and it also respects the blood decree-law. The PRP/media ratio should provide a sufficient nutrition supply to prevent cellular starvation, that is, PRP ≤ 10% (Vol/Vol) and thus best mimic the conditions in vivo.

Adipose-derived stem cells combined with platelet-rich plasma enhance wound healing in a rat model of full-thickness skin defects

“…PRP is another effective agent for wound healing because it contains abundant growth factors and other substances that can restore growth factors in diabetic wounds. The cellular processes, such as chemotaxis, cell differentiation and angiogenesis, and several target cells in wound healing were stimulated by PRP [30,31]. The antiapoptotic effect of PRP through the activation of the Bcl-2 protein and Akt signaling was a contributing factor to improve wound healing by stimulating hair growth [32].…”

Evaluation of adding platelet‐rich plasma to combined medical therapy in androgenetic alopecia

“…5,8,19 The anti-apoptotic effect of PRP has been described as the most important factors stimulating hair regrowth through the Bcl-2 protein activation (anti-apoptotic regulator) and Akt signaling, improving the dermal papilla cells survival (DPCs) during the hair cycle. 20 In this study, after 3 sessions of PRP injection, patients were satisfied with improvement in form of significant increase in hair density and detection of small regrown hairs.…”

“…The anti‐apoptotic effect of PRP has been described as the most important factors stimulating hair regrowth through the Bcl‐2 protein activation (anti‐apoptotic regulator) and Akt signaling, improving the dermal papilla cells survival (DPCs) during the hair cycle 20 …”

Technical Procedures for Preparation and Administration of Platelet-Rich Plasma and Related Products: A Scoping Review

“…To the best of our knowledge, this is the first attempt to review comparative studies that focused on different methods for each stage of PRP processing. In the systematic review conducted by Gentile et al focusing on optimal concentration of PRP, results shown that higher concentrations of PRP may be associated with a significant decline in cell proliferation (Gentile and Garcovich, 2020b), which stresses the need for standardization of procedures in this regard. In other systematic review, recently conducted by Chahla et al (2017) studies in which PRP was used for musculoskeletal conditions were assessed in relation to the reporting of the applied methods for PRP processing or of the composition of the final product.…”