In vitro cell-type specific biological response of human periodontally related cells to platelet-rich plasma.

OBJECTIVES: Platelet-rich plasma is a blood-derived fraction containing high concentrations of platelets and growth factors. Applied in the form of a gel on surgical wounds, it is able to stimulate hard and soft tissue repair and has been proposed for use in the field of periodontal regeneration. However to date, little is known about the biological interactions between platelet-rich plasma and periodontally related cells. In this study, we investigated the effects between platelet-rich plasma and cell populations involved in periodontal regeneration, namely primary human periodontal ligament cells, gingival fibroblasts and keratinocytes. MATERIAL AND METHODS: The proliferation of human periodontal ligament cells, gingival fibroblasts and keratinocytes by [3H]thymidine incorporation was assessed. The alkaline phosphatase activity and type I collagen levels of human periodontal ligament cells were also evaluated by a spectrophotometric assay and western blot analysis, respectively. RESULTS: Incubation of human periodontal ligament cells with platelet-rich plasma resulted in time-dependent growth stimulation (up to fourfold of control at 72 h). Likewise, an increase in the specific activity of alkaline phosphatase (fourfold at 6 days) and collagen (twofold at 7 days) was observed. Platelet-rich plasma also enhanced human gingival fibroblasts proliferation by twofold, whereas it inhibited human keratinocytes growth by 40%, with respect to their own controls at 72 h. CONCLUSION: Cell populations related to periodontal tissue were differently affected by platelet-rich plasma. In fact, a strong stimulation of human periodontal ligament cells proliferation, a minor increase in the growth rate of human gingival fibroblasts and a marked decrease of human keratinocytes proliferation were evident. In addition, in human periodontal ligament cells increased collagen and alkaline phosphatase activity levels were observed. These findings appear interesting in view of platelet-rich plasma utilization in periodontal regeneration.

Ex vivo expansion of bone marrow stromal cells by platelet-rich plasma: a promising strategy in maxillo-facial surgery.

The aim of our study is to evaluate in vitro the response of bone marrow stromal cells (BMSCs) to platelet-rich plasma (PRP), in order to clarify the potential role of their combined use in a preclinical phase preceding BMSCs transplantation for bone repair and regeneration procedures. The incubation of BMSCs with PRP promoted a remarkable, dose- and time- dependent, growth stimulation, that was paralleled to a strong increase in the quantity of type I collagen and to a significant decrease in the activity of the early osteoblastic differentiation marker, alkaline phosphatase (AP). Once PRP was removed and osteogenic inducers were added, AP returned to levels comparable to the control, while the late phenotypic markers, osteocalcin and matrix calcification, were enhanced to higher levels than in controls. Our data demonstrate that PRP induces a remarkable ex vivo enrichment of BMSCs maintaining their differentiative potential. Thus PRP represents a valid preclinical tool for obtaining an effective, rapid and safe ex vivo expansion of BMSCs prior to their clinical utilization in bone engineering.