Leukocyte-platelet-rich plasma (L-PRP) induces an abnormal histophenotype in craniofacial bone repair associated with changes in the immunopositivity of the hematopoietic clusters of differentiation, osteoproteins, and TGF-β1.

Background: Leukocyte-platelet-rich plasma (L-PRP) is considered an important source of growth factors, especially Transforming growth factor β 1 (TGF-β1), which modulates the proliferation and regulation of mesenchymal cells, and also exerts an influence on the hematopoiesis, osteogenesis, and adipogenesis in bone microenvironment. Thus, the aim of this study was to evaluate the effect of L-PRP on the calvarial bone repair and compare its results on the presence of TGF-β1, CD34, CD45, bone morphogenetic protein 2 (BMP2), BMPR1B, and Runx2 proteins detected by immunohistochemistry.

Material And Methods: Four bone defects were created on the calvaria of 23 rabbits.

Platelet-rich plasma (PRP) impairs the craniofacial bone repair associated with its elevated TGF-β levels and modulates the co-expression between collagen III and α-smooth muscle actin.

Transforming growth factor-β (TGF-β) is considered the main inducer of both the α-smooth muscle actin (α-SMA) phenotype and collagen synthesis and deposition and plays a significant role in the tissue repair and the development of fibrosis. Since the PRP constitutes an important source of TGF-β and its efficacy on the craniofacial bone repair remains controversy, the aim of this study was to evaluate the effect of PRP in the presence of levels of TGF-β on PRP samples, as well as in the presence of collagen III and α-SMA+ cells, while comparing these results by means of a histomorphometric analysis of the bone matrix and fibrous deposition on the bone repair. Four bone defects of 16 mm(2) were created on the calvarium of 21 rabbits.

Platelet-rich plasma diminishes calvarial bone repair associated with alterations in collagen matrix composition and elevated CD34+ cell prevalence.

The interaction between platelets and both type I and III collagens plays an important role in modulating platelet adhesion and aggregation, also contributing to the chemotaxis of CD34+ cells. The interaction with type III collagen can maintain high levels of collagen and alter the biology of bone repair when the PRP is used. The aim of this study was to evaluate the effect of platelet-rich plasma (PRP) and autograft on the presence of type III and type I collagens, the ratio between them, as well as the presence of CD34+ progenitor cells, while comparing these results by means of a histomorphometric analysis of the bone tissue.