Bioactive Fibrin Scaffolds for Use in Musculoskeletal Regenerative Medicine

Abstract Autologous fibrin matrices derived from the Leukocyte and Platelet Rich Plasma (L-PRP) and Leukocyte and Platelet Rich Fibrin (L-PRF) techniques present great potential to act as a bioactive scaffold in regenerative medicine, contributing to the maintenance of cell viability, proliferation stimulus and differentiation. In contrast, there are few studies that characterize the bioactive potential of these fibrin scaffolds by considering the process of production. The objective of this work was to characterize the intrinsic potential of maintaining cell viability of different fibrin scaffolds containing platelets and leukocytes. In order to achieve that, blood samples from a volunteer were collected and processed to obtain fibrin clots using the suggested techniques. To characterize the potential for in vitro viability, mesenchymal stem cells from human infrapatellar fat were used. The scaffolds were cellularized (1x105 cells/scaffolds) and maintained for 5 and 10 days under culture conditions with Dulbecco's Modified Eagle Medium, without addition of fetal bovine serum, and subsequently subjected to analyses by Fourrier transform infra-red spectroscopy, circular dichroism and fluorescence microscopy. The results demonstrated distinct intrinsic potential viability between the scaffolds, and L-PRP was responsible for promoting higher levels of viability in both periods of analysis. No viable cells were identified in the fibrin matrix used as controls. These results allow us to conclude that both fibrin substrates have presented intrinsic potential for maintaining cell viability, with superior potential exhibited by L-PRP scaffold, and represent promising alternatives for use as bioactive supports in musculoskeletal regenerative medicine.

Injeção de agregados plaquetários no rejuvenescimento facial: uma revisão sistemática / Injection of platelet aggregates in facial rejuvenation: a systematic review

Introdução: Essa revisão sistemática foi conduzida para avaliar se a associação da aplicação da injeção de agregados plaquetários quando comparada a outras terapias faciais favorece no rejuvenescimento facial em pacientes adultos. Métodos: A pesquisa buscou ensaios clínicos randomizados que compararam uso de técnicas de rejuvenescimento facial isoladas com as mesmas técnicas aliadas à injeção de agregados plaquetários. A busca foi realizada em bases de dados indexadas e literatura cinzenta. A ferramenta de risco de viés da "Cochrane Collaboration" foi aplicada para a avaliação da qualidade dos estudos. Resultados: Foram identificados 7137 artigos. Apenas quatro estudos permaneceram na síntese qualitativa, e os demais foram considerados com risco indefinido de viés nos domínios chaves. Conclusão: Existem poucos estudos na literatura que comparam o uso de agregados plaquetários em rejuvenescimento facial e os que estão disponíveis têm risco de viés "indefinido" ou "alto". Há necessidade de realizar mais estudos clínicos bem delineados que comparem o uso de injeção de agregados plaquetários associados ou não às técnicas de rejuvenescimento facial.

Introduction: This systematic review was conducted to assess whether the use of a platelet aggregate injection with or without associated facial rejuvenation techniques favors facial rejuvenation in adult patients. Methods: Randomized clinical trials that compared the use of techniques for facial rejuvenation alone with the same techniques coupled with the injection of platelet aggregates were searched. The search was performed in indexed databases and in the gray literature. The Cochrane Collaboration bias risk tool was applied to assess the quality of the studies. Results: In total, 7137 articles were identified. Only four studies remained in the qualitative synthesis, and the others were considered as having undefined bias risk in the key domains. Conclusion: There are few studies in the literature that compare the use of platelet aggregates in facial rejuvenation and those that are available have a risk of "undefined" or "high" bias. There is a need for more well-designed clinical studies comparing the use of platelet aggregate injection with or without associated facial rejuvenation techniques.