Platelet Concentration in Platelet-Rich Plasma Affects Tenocyte BehaviorIn Vitro

Abstract

Since tendon injuries and tendinopathy are a growing problem, sometimes requiring surgery, new strategies that improve conservative therapies are needed. Platelet-rich plasma (PRP) seems to be a good candidate by virtue of its high content of growth factors, most of which are involved in tendon healing. This study aimed to evaluate if different concentrations of platelets in PRP have different effects on the biological features of normal human tenocytes that are usually required during tendon healing. The different platelet concentrations tested (up to 5 × 106 plt/µL) stimulated differently tenocytes behavior; intermediate concentrations (0.5 × 106, 1 × 106 plt/µL) strongly induced all tested processes (proliferation, migration, collagen, and MMPs production) if compared to untreated cells; on the contrary, the highest concentration had inhibitory effects on proliferation and strongly reduced migration abilities and overall collagen production but, at the same time, induced increasing MMP production, which could be counterproductive because excessive proteolysis could impair tendon mechanical stability. Thus, these in vitro data strongly suggest the need for a compromise between extremely high and low platelet concentrations to obtain an optimal global effect when inducing in vivo tendon healing.

Review of concentration yields in commercially available platelet-rich plasma (PRP) systems: a call for PRP standardization

“…Yamaguchi et al 34 showed PRP concentration had a dose-dependent effect on intestinal anastomotic healing in rats, where a lower PRP platelet concentration (2 000 000/µL) exerted positive effects, while the higher PRP platelet count (5 000 000/µL) was harmful to healing. A second study by Giusti et al demonstrated positive effects on human tenocyte proliferation using a concentration of 500 000 and 1 000 000/µL while again 5 000 000/µL induced cell death 35. There currently is not a consensus for an optimal PRP dose, but further clinical studies will hopefully identify therapeutic dose ranges for particular indications.…”

Platelet Derivatives in Regenerative Medicine: An Update

“…Indeed, comparison of different platelet concentrations in PRP showed in vitro that rates of 2.5 fold gave better results on fibroblast and osteoblast proliferation and functionality [46]. In contrast, a recent in vitro study aimed to evaluate the effects of different platelet concentrations in PRP on the biological features of normal human tenocytes, which are usually required during tendon healing, suggests the need for a compromise between extremely high and low platelet concentrations to obtain an optimal global effect when inducing in vivo tendon healing [48].…”

Réflexions relatives au traitement des tendinopathies par infiltration de PRP

“…Selon [4][5][6] ; une concentration supérieure à 1200 000 plaquettes pourrait effectivement s'avérer néfaste [6][7][8]. On devrait pouvoir injecter un PRP reproductible (concentration plaquettaire identique) chez tous les patients [9].…”