Development of Tissue-Engineered Periodontal Regeneration Using Platelet-Rich Plasma and Periodontal Ligament Cells

富血小板血浆（PRP）含有高水平的PDGF和TGF-β。PRP刺激成骨细胞DNA合成和细胞分裂，但抑制上皮细胞分裂。PRP还能刺激牙龈成纤维细胞和牙周韧带细胞的DNA合成。纤维蛋白与PRP中存在的生长因子结合可能有效地促进牙周组织损伤部位的伤口愈合。下一阶段的随机对照临床试验是比较PRP+羟基磷灰石（HA）与HA和生理盐水的混合物治疗人类骨内缺陷的效果。PRP+HA导致明显更有利的临床改善。此外，体外实验数据显示，PRP增强了碱性磷酸酶（ALP）活性，但TGF-β和PDGF都没有复制这种效果。由于在多种组织中，ATP的刺激通常伴随着矿化的促进，因此我们检测了PRP在PDL细胞培养中刺激矿化的能力。PRP显著上调Cbfa1、BSP和OCN等成骨细胞标志物的表达，并同时刺激pc包被板上培养的PDL细胞的矿化。透射电镜结果显示矿化针状体沉积在血小板聚集体上，而不是在基质囊泡状结构上或内部。因此，PRP通过刺激细胞ALP活性和在培养中提供矿化核来促进体外矿化。采用人培养的牙龈上皮片作为自体移植材料进行牙龈组织再生，治疗慢性脱屑性牙龈炎。手术后6个月，治疗部位的健康角化牙龈得到改善。在“培养骨”项目中，我们通过改进旋转培养方法，成功地将牙周韧带细胞植入多孔羟基磷灰石块中。

Platelet-Rich Plasma(PRP) contained high levels of PDGF and TGF-β. PRP stimulated osteoblastic DNA synthesis and cell division, but suppressed epithelial cell division. PRP also stimulated DNA synthesis in gingival fibroblasts and periodontal ligament cells. Fibrin in combination with growth factors present in PRP might effectively promote wound healing at sites of injury in periodontal tissue. As a next stage, randomized controlled clinical trial was to compare PRP+hydroxyapatite(HA), with the mixture of HA and saline in the treatment of human intrabony defects. PRP+HA led to a significantly more favorable clinical improvement. In addition to in vitro data, PRP enhanced alkaline phosphatase(ALP) activity, but neither TGF-β nor PDGF replicated this effect. As stimulation of ATP often accompanies promotion of mineralization in a variety of tissues, the ability of PRP to stimulate mineralization in PDL cell cultures was examined. PRP substantially up-regulated expression of several osteoblastic markers such as Cbfa1,BSP, and OCN, and concomitantly stimulated mineralization in PDL cells cultured on PC-coated plates. TEM findings demonstrated that mineralized spicules were deposited onto platelet aggregates but not on or within matrix vesicle-like structures. Therefore, PRP promotes in vitro mineralization both by stimulating cellular ALP activity and by providing a nucleus for mineralization in culture.Human cultured gingival epithelial sheets were used as an autografting material for regenerating gingival tissue for treatment of chronic desquamative gingivitis. Six months post-surgery in treated sites, there were gains in healthy keratinized gingiva.In the "cultured bone" project, we succeeded incorporating periodontal ligament cells to porous hydroxyapatite block by modifying the rotary culture method.