Park Eun-Jin, Kim Eun-Seok, Weber Hans-Peter, Wright Robert F, Mooney David J
Department of Dentistry, School of Medicine, Ewha Women's University, Seoul, South Korea.
Int J Oral Maxillofac Implants. 2008 Sep-Oct;23(5):818-26.
The purpose of this study was to modify the method of platelet-rich plasma (PRP) preparation for obtaining optimal angiogenic potential and accelerate bone healing. Also, the potential synergistic effect of a suboptimal concentration of bone morphogenic protein-2 (BMP-2) and modified PRP (mPRP) on bone healing was evaluated in vivo.
The angiogenic factor-enriched PRP, which included peripheral blood mononuclear cells (mostly lymphocytes and monocytes, excluding polymorphonuclear leukocytes [PMNs], was achieved by lowering concentrations of thrombin and CaCl2, after pre-activation with shear stress using a table-top vortex machine and collagen. In vitro, endothelial cell migration activity in the mPRP group was compared to conventional PRP preparation using a modified Boyden chamber assay. In an animal study, PGA scaffold, PGA scaffold + mPRP, PGA scaffold + mPRP + rhBMP-2, and PGA scaffold + rhBMP-2 were applied to critical-sized calvarial defects in 28 nude rats. At 2 weeks, periosteal blood flow was measured using laser Doppler perfusion imaging, and bone formation was evaluated at 8 weeks by histology, dual energy x-ray absorptiometry, and micro-computed tomography.
mPRP induced faster migration of cord blood-derived outgrowth endothelial-like cells. In vivo, the group with mPRP with a low dose of rhBMP-2 showed significantly increased numbers of blood vessels at 2 weeks and notable synergistic effect on bone healing at 8 weeks as evaluated with histology, bone mineral density and bone mineral content, and muCT.
The mPRP used in this study improved vascular perfusion around the defect and resulted in enhanced bone healing. Also, combining mPRP with a suboptimal dosage of rhBMP-2 improved bone formation and enhanced bone density.
本研究旨在改进富血小板血浆（PRP）的制备方法，以获得最佳血管生成潜力并加速骨愈合。此外，还在体内评估了次优浓度的骨形态发生蛋白-2（BMP-2）与改良PRP（mPRP）对骨愈合的潜在协同作用。
通过使用台式涡旋仪和胶原蛋白进行剪切应力预激活后，降低凝血酶和氯化钙的浓度，获得富含血管生成因子的PRP，其中包括外周血单核细胞（主要是淋巴细胞和单核细胞，不包括多形核白细胞[PMN]）。在体外，使用改良的博伊登室试验比较mPRP组与传统PRP制备中内皮细胞的迁移活性。在一项动物研究中，将PGA支架、PGA支架+mPRP、PGA支架+mPRP+rhBMP-2和PGA支架+rhBMP-2应用于28只裸鼠的临界尺寸颅骨缺损。在2周时，使用激光多普勒灌注成像测量骨膜血流，并在8周时通过组织学、双能X线吸收法和微计算机断层扫描评估骨形成。
mPRP诱导脐血来源的内皮样细胞迁移更快。在体内，低剂量rhBMP-2的mPRP组在2周时血管数量显著增加，并且在8周时，通过组织学、骨矿物质密度和骨矿物质含量以及微计算机断层扫描评估，对骨愈合具有显著的协同作用。
本研究中使用的mPRP改善了缺损周围的血管灌注，并导致骨愈合增强。此外，将mPRP与次优剂量的rhBMP-2联合使用可改善骨形成并提高骨密度。
