28 July 2020

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Platelet-rich plasma: a treatment option for osteonecrosis?

Alessandra Abbà

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Bisphosphonates are widely used for the treatment of abnormal bone metabolism for example in osteoporosis. Their continuative use leads to a strong inhibition of osteoclast activity and therefore to a possible correlated side effect that is osteonecrosis in the jaw (BRONJ). This condition is defined as a disease with exposition of bone in the maxilla or mandible and lack of wound healing. The occurrence ofBRONJ  depends in particular on the type, duration and form of bisphosphonates  administration. How to manage the treatment of BRONJ is still topic of debate in literature and a predictable protocol to apply in these cases has not yet been established. A variety of surgical and non-surgical treatment options has been proposed for the resolution of BRONJ  for example debridement of the affected area combined with application of platelet-rich blood products. Platelet-rich plasma (PRP)   and  platelet-rich fibrin (PRF) are autologous growth factors which help the rapid healing of wounds by promoting vascular structures.  
 The present study aimed to investigate the use of platelet-rich plasma (PRP)   on tooth extraction sites in rats treated with bisphosphonates  by using imaging, microscopic, and immunohistochemical analyses.    

Materials and method
bisphosphonates  -related osteonecrosis of the jaw (BRONJ) was induced in thirty male rats by administration of 0.035 mg/kg zoledronic acid intravenously for 8 weeks divided into four administrations and by subsequent extraction of their upper right central incisors. The sample were then divided into the following two groups:
1) marginal resection of BRONJ followed by the use of PRP;
2) resection of BRONJ but without the use of PRP ; and evaluated after 14, 28, and 42 days.    

Results
Clinical, microtomographic, microscopic, and immunohistochemical (IHC) analyses were performed. Histomorphometric analysis in the computed microtomography examination showed slightly greater (no statistically significant) new bone formation in the group receiving PRP, as regard bone structure. Microscopic examination gave a detailed investigation of the repair process that revealed significant new bone formation compared to the group without PRP  with G1 presenting greater vascularization and a slightly higher VEGF expression (results recorded on days 28 and 42). The rate of bone remodeling was found to be normal within immunohistochemical parameters, as demonstrated by the equilibrium in the RANKL:OPG ratio of expression levels.

Conclusions
Data recorded from the analyses indicated that the use of PRP improves the resolution process of BRONJ. The experimental group (G1) that received treatment with PRP presented improved bone repair compared to the control group (G2).  

For additional information: Treatment of bisphosphonate-related osteonecrosis using platelet-rich plasma: microtomographic, microscopic, and immunohistochemical analyses.