Avaliação da migração das células progenitoras após terapia da tendinite equina / Migration evaluation of progenitor cells after treatment of equine tendinitis

A terapia celular vem sendo utilizada com resultados promissores no tratamento da tendinite equina, entretanto ainda existem dúvidas quanto à persistência e ao comportamento dessas células quando implantadas no local da lesão, e quanto à sua migração para outros focos inflamatórios. O objetivo deste estudo foi avaliar a marcação das células-tronco mesenquimais (CTMs) com nanocristal antes e após o implante em lesões tendíneas experimentais do tendão flexor digital superficial (TFDS) de equinos, bem como observar a possibilidade de migração das CTMs marcadas para outro foco de lesão, o membro contralateral do mesmo animal. Para isso, foi realizada a indução de lesão experimental no TFDS em ambos os membros torácicos de cinco equinos e, após sete dias, foram implantadas as CTMs autólogas marcadas com o nanocristal Qtracker 655 em um dos membros dos animais. Após sete dias do implante, foi realizada a biópsia tendínea para posterior avaliação histopatológica, utilizando-se microscopia com fluorescência. Também foi realizado o teste de viabilidade celular antes e após a incubação com o nanocristal. As CTMs marcadas e injetadas no tecido tendíneo mantiveram sua fluorescência sete dias após seu implante, e não ocorreu migração para o membro contralateral. O uso do nanocristal para a marcação das CTMs derivadas da medula óssea equina mostrou-se efetivo pelo fato de essa nanopartícula não ter alterado a viabilidade celular e por ela ter permanecido ativa durante o período implantado...

Cell therapy has been used with promising results in the treatment of equine tendinitis. However, there are still doubts about the persistence and behavior of these cells implanted in the injured tissue and their migration to other inflamed sites. The aim of this study was to evaluate the labeling of mesenchymal stem cells (MSCs) with nanocrystals before and after implantation in experimental tendinitis of the superficial digital flexor tendon (SDFT) of horses, observing the migration possibility of MSCs marked to another lesion, performed on the contralateral limb of the same animal. An experimental lesion was induced in SDFT in both forelimbs of five horses, and after seven days autologous MSCs labeled with Qtracker(r) 655 were implanted in one member of the animals. Tendon biopsy was performed for subsequent histopathological evaluation using fluorescence microscopy seven days after the implant. Cell viability test was also performed before and after incubation with the cell labeling kit. MSCs labeled and injected into the tendon tissue maintained their fluorescence seven days after their implantation and there was no migration to the contralateral limb. The use of nanocrystals for labeling MSCs was effective because it does not alter cell viability and remains active during the experimental period...

In vitro cultivation of canine multipotent mesenchymal stromal cells on collagen membranes treated with hyaluronic acid for cell therapy and tissue regeneration

Support structures for dermal regeneration are composed of biodegradable and bioresorbable polymers, animal skin or tendons, or are bacteria products. The use of such materials is controversial due to their low efficiency. An important area within tissue engineering is the application of multipotent mesenchymal stromal cells (MSCs) to reparative surgery. The combined use of biodegradable membranes with stem cell therapy may lead to promising results for patients undergoing unsuccessful conventional treatments. Thus, the aim of this study was to test the efficacy of using membranes composed of anionic collagen with or without the addition of hyaluronic acid (HA) as a substrate for adhesion and in vitro differentiation of bone marrow-derived canine MSCs. The benefit of basic fibroblast growth factor (bFGF) on the differentiation of cells in culture was also tested. MSCs were collected from dog bone marrow, isolated and grown on collagen scaffolds with or without HA. Cell viability, proliferation rate, and cellular toxicity were analyzed after 7 days. The cultured cells showed uniform growth and morphological characteristics of undifferentiated MSCs, which demonstrated that MSCs successfully adapted to the culture conditions established by collagen scaffolds with or without HA. This demonstrates that such scaffolds are promising for applications to tissue regeneration. bFGF significantly increased the proliferative rate of MSCs by 63% when compared to groups without the addition of the growth factor. However, the addition of bFGF becomes limiting, since it has an inhibitory effect at high concentrations in culture medium.