Platelet‐rich fibrin elicits an anti‐inflammatory response in macrophages in vitro

Abstract

Background Platelet‐rich fibrin (PRF) serves as a reservoir of bioactive molecules to support wound healing and bone regeneration. The beneficial action of PRF might involve macrophage polarization from proinflammatory M1 toward pro‐resolving M2 phenotypes. This study aims to evaluate the effect of PRF on macrophage polarization. Methods Murine primary macrophages and RAW 264.7 cells were exposed to saliva and lipopolysaccharides (LPS) with and without PRF lysates obtained by repeated freeze‐thawing or the secretome of PRF membranes, termed PRF conditioned medium. The expression of the M1 marker genes interleukin 1β (IL1β) and interleukin 6 (IL6) along with the M2 markers arginase‐1 and chitinase‐like 3 (Chil3 or YM1) were evaluated by real time polymerase chain reaction. Immunoassay and immunofluorescence staining were performed for IL6 and p65 translocation, a subunit nuclear factor kappa‐light‐chain‐enhancer of activated B cells (NF‐kB), respectively. Results We report here that PRF lysates and PRF conditioned medium, the latter containing the secretome, greatly decreased the proinflammatory response of primary macrophages and RAW 264.7 cells as indicated by the expression of IL1β and IL6. The anti‐inflammatory activity of PRF lysates was further confirmed by IL6 immunoassay. Moreover, PRF lysates suppressed the translocation of p65 from the cytoplasm into the nucleus after incubation with saliva. In support of M2 polarization, PRF lysates and PRF conditioned medium enhanced the expression of arginase‐1 and YM1 in primary macrophages. Conclusion Our results indicate that PRF holds an anti‐inflammatory activity and shifts the macrophage polarization from an M1 toward an M2 phenotype.

Effect of platelet-rich fibrin on cell proliferation, migration, differentiation, inflammation, and osteoclastogenesis: a systematic review of in vitro studies

“…These observations were reproduced in embryonic kidney fibroblasts and in various cell lines such as HEK293, MG-63 osteosarcoma cells, human oral keratinocytes, SIRC, and 3T3 cells [18]. Mesenchymal cells, endothelial cells [23,42,55,63], epithelial cells [22], and macrophages [69] also responded to PRF with increasing proliferation. In contrast, PRF failed to induce proliferation of L929 fibroblasts [53] and human mesenchymal stem cells on collagen scaffolds [17].…”

“…Moreover, PRF reduced LPS-induced cytokine production in pulp cells and enhanced the up-regulation of odontoblastic differentiation markers DSP and DMP-1 in these cells [34]. Similarly, PRF suppressed the LPS-and saliva-induced pro-inflammatory cytokines on primary and RAW264.7 macrophages and attenuated the translocation of NF-κB into the nucleus [69]. This antiinflammatory effect was replicated in gingival fibroblasts [61].…”

“…For example, PRF reduced the LPS-induced proinflammatory cytokine release in gingival fibroblasts [61]. In addition, we have recently shown that PRF reduces the expression of the M1 marker genes interleukin 1β (IL1β) and interleukin 6 (IL6) in bone marrow macrophages [69]. This anti-inflammatory effect might be explained by the high amounts of TGFβ in PRF [73] capable of modulating the M1 and M2 polarization along with the generation of proresolving lipid mediators [69].…”

Platelet‐rich fibrin suppresses in vitro osteoclastogenesis

“…We decided to use the same protocol and hardware to minimize the number of variables and achieve reproducibility in accordance to previous recommendations . The decrease in osteoclastogenesis might be associated with the M1‐to‐M2 shift of macrophages exposed to PRF lysates . Future research should focus on the molecular mechanism by which PRF inhibits osteoclastogenesis not only in vitro, but also in vivo and whether different PRF protocols modulate osteoclastogenesis differently.…”

“…29 The decrease in osteoclastogenesis might be associated with the M1-to-M2 shift of macrophages exposed to PRF lysates. 30 Future research should focus on the molecular mechanism by which PRF inhibits osteoclastogenesis not only in vitro, but also in vivo and whether different PRF protocols modulate osteoclastogenesis differently. The most suitable preparation of PRF to inhibit osteoclastogenesis and obtain the best clinical outcomes in ridge preservation remains unclear.…”