The platelet‐rich plasma and mesenchymal stem cell milieu: A review of therapeutic effects on bone healing

Abstract

Platelet‐rich plasma is autologous plasma that contains concentrated platelets compared to whole blood. It is relatively inexpensive to produce, can be easily isolated from whole blood, and can be administered while the patient is in the operating room. Further, because platelet‐rich plasma is an autologous therapy, there is minimal risk for adverse reactions to the patient. Platelet‐rich plasma has been used to promote bone regeneration due to its abundance of concentrated growth factors that are essential to wound healing. In this review, we summarize the methods for producing platelet‐rich plasma and the history of its use in bone regeneration. We also summarize the growth factor profiles derived from platelet‐rich plasma, with emphasis on those factors that play a direct role in promoting bone repair within the local fracture environment. In addition, we discuss the potential advantages of combining platelet‐rich plasma with mesenchymal stem cells, a multipotent cell type often obtained from bone marrow or fat, to improve craniofacial and long bone regeneration. We detail what is currently known about how platelet‐rich plasma influences mesenchymal stem cells in vitro, and then highlight the clinical outcomes of administering platelet‐rich plasma and mesenchymal stem cells as a combination therapy to promote bone regeneration in vivo.

Platelet-Rich Plasma Combined With Autologous Grafting in the Treatment of Long Bone Delayed Union or Non-union: A Meta-Analysis

“…For example, activated PDGF was reported to attach to transmembrane receptors on osteoblasts, osteoclasts, chondrocytes, fibroblasts, and macrophages to stimulate mitogenesis, angiogenesis, bone remodeling, and phagocytosis of damaged tissue during fracture healing (43). Recent evidence also suggests that growth factors derived from PRP could interact with mesenchymal stem cells, which synergistically regulate the healing of bone defects (44). The exact mechanisms and key pathways underlying the benefits of combined PRP and autologous bone grafting on healing of long bone non-union deserve further studies.…”

Regenerative Medicine for Equine Musculoskeletal Diseases

“…During the remodelling phase, first a fibrocartilaginous and then a bony callus is formed providing more stability and vascularisation. In the final phase of fracture healing, excess callus is resorbed, and the normal bone architecture restored [ 235 , 236 , 237 , 262 , 270 , 271 , 272 ]. New therapeutic approaches are based on and utilise some of the cells, growth factors, cytokines and signalling molecules involved in bone regeneration [ 235 , 236 , 237 , 239 , 273 , 274 , 275 , 276 ].…”

“…To date, autologous bone grafting is still considering the gold standard when dealing with equine fractures. Although providing the three key criteria for bone regeneration (osteogenesis, osteoinduction and osteoconduction), donor site morbidity is a major limitation of bone grafting [ 270 , 279 ]. Thus, other grafting techniques are being tested as carriers for cells and factors or/and as osteoconductive materials.…”

“…As platelets have an essential role in fracture healing by contributing to the hematoma formation, and later on by releasing growth factors from their alpha-granules, the potential of PRP to promote bone regeneration seems evident [ 270 ]. In a meta-analysis of PRP in the animal long bone model by Gianakos et al, which included 29 studies, 89% reported improved bone healing with PRP shown in histology and 100% in radiographs [ 281 ].…”

Chemotactic and Angiogenic Potential of Mineralized Collagen Scaffolds Functionalized with Naturally Occurring Bioactive Factor Mixtures to Stimulate Bone Regeneration

“…Among them, platelet-rich plasma (PRP) has been used for many years to promote wound healing and tissue regeneration in orthopedic, maxillofacial and plastic surgery. With respect to bone repair, the published results are inconsistent: while some studies show a positive effect on bone healing, others show no significant benefit [16]. Thus, the efficacy of PRP and other platelet concentrates in promoting bone regeneration is at the center of a recent academic debate [17,18].…”