Agitation-dependent biomechanical forces modulate GPVI receptor expression and platelet adhesion capacity during storage

Background Continuous agitation during storage slows down the platelet storage lesions. However, in special circumstances, manual-mixing can be alternatively used to store products for short time periods without compromising platelet quality. Based on this finding, and given the role of shear stress in modulating receptor expression, we were interested in comparing the levels of platelet adhesion receptor, GPVI and platelet adhesion capacity under each storage condition. Methods Platelet concentrates (PCs) were divided into three groups: continuously-agitated PCs (CAG-PCs) with or without PP2 (Src kinase inhibitor) and manually-mixed PCs (MM-PCs). Platelet count/MPV, swirling, GPVI and P-selectin expression, GPVI shedding, platelet adhesion/spreading to collagen were examined during 5 days of storage. Results While MM- and CAG-PCs showed similar levels of P-selectin expression, GPVI expression was significantly elevated in MM-PCs with lower GPVI shedding/expression ratios, enhanced platelet adhesion/spreading and swirling in manually-mixed PCs. Of note, CAG-PCs treated with PP2 also demonstrated lower P-selectin expression and GPVI shedding, higher GPVI expression and attenuated swirling and spreading capability. Conclusion Given the comparable platelet activation state in MM and CAG-PCs as indicated by P-selectin expression, enhanced platelet adhesion/spreading in MM-PCs, along with relatively higher GPVI expression here, supports previous studies demonstrating a role for biomechanical forces in modulating GPVI-dependent function. Thus, lower GPVI expression in CAG-PCs may be due to shear forces induced by agitation, which keeps this receptor down-regulated while also attenuating platelet adhesion/spreading capacities during storage. Low platelet function in PP2-CAG-PCs also highlights the importance of Src-kinases threshold activity in maintaining platelets quality.

A Comparative Study of the Effects of Platelet-Rich Fibrin, Concentrated Growth Factor and Platelet-Poor Plasma on the Healing of Tooth Extraction Sockets in Rabbits

Background：Autologous platelet concentrate has been widely used to encourage the regeneration of hard and soft tissues. Up to now, there are three generations of autologous platelet concentrates. Many studies have shown that different autologous platelet concentrates have different healing effects. However, these differences still need to be further verified and discussed. The purpose of this study was to explore and compare the effects of platelet-rich fibrin, concentrated growth factor and platelet-poor plasma on the healing of tooth extraction sockets in New Zealand rabbits. Methods：A total of 24 healthy male New Zealand white rabbits aged 8-12 weeks were selected. The experimental animals were randomly divided into four groups: three experimental groups were respectively implanted with PPP, CGF and PRF gel after bilateral mandibular anterior teeth were extracted, and the control group did not implant any material. The alveolar bone of the mandibular anterior region was taken at 2, 4 and 8 weeks after operation. The height and width of the extraction wound were detected by CBCT, the growth of the new bone was observed by HE and Masson staining, and the expression of osteogenic genes was detected by real-time PCR. Data were analyzed using IBM SPSS statistical package 22.0.Results: The radiological results showed that alveolar bone absorption in all groups gradually increased over time. However, the experimental groups showed lower amounts of bone absorption. The histological results showed that new bone formation was observed in all groups. Over time, the new bone trabeculae of the CGF group became closely aligned while those in the PPP and PRF groups remained scattered. PCR results showed that the expression of BMP-2 and ALP was higher in the experimental groups than the control group.Conclusion: In conclusion, the application of PRF, CGF and PPP in tooth extraction sockets effectively promoted bone regeneration. CGF showed more effective bone induction and tissue regeneration ability in the long term.

Comparative Evaluation of Open Flap Debridement Therapy with Two Different Types of Platelet Concentrates, T-PRF and L-PRF as Adjuncts- A Systematic Review

Conventional Periodontal therapy such as scaling and root planing and open flap debridement aims to halt the inflammation process and promotes repair of disease-related defects. Current regenerative procedures offers a limited potential toward attaining a complete periodontal restoration and none is considered a gold standard in the treatment of intrabony defects. This study was done to compare the efficiency of Titanium-Platelet Rich Fibrin and Leukocyte-Platelet Rich Fibrin as adjuncts to Open Flap Debridement therapy to treat intra-bony periodontal defects. A search was conducted through PubMed and various other databases such as Cochrane, Google Scholar and EBSCO Host , under the key words, OFD , T-PRF,L-PRF, Clinical Outcomes, Comparison and Randomised Contolled Trials. Six relevant articles were selected for analysis. Compared to non-platelet concentrates, L-PRFproves to be the better adjunct to open flap debridement therapy. When compared to T-PRF, however, L-PRF has comparatively inferior properties of bone defect resolution and fill.We can conclude that T-PRF has better properties, greater bone defect fill and defect resolution as compared to L-PRF.