Tenogenic potential of tendon-derived mesenchymal stem cells isolated post-mortem: Impact of cryopreservation

In situ injection of mesenchymal stem cells appears as a promising treatment of tendinopathies. Tendon-derived mesenchymal stem cells (TDSCs) are widely studied and show a lot of interesting characteristics for clinical use. The aim of this study is to confirm the tenogenic potential of cryopreserved TDSCs and to confirm their ability to produce type I and/or type III collagens fibers in culture. Tendon-derived mesenchymal stem cells are harvested from the tendon no later than 72 h post-mortem. Their tenogenic potential has been assessed by quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) analysis of different genes involved in tenogenic differentiation. The stemness phenotype of TDSCs has been confirmed by flow cytometry. In order to demonstrate their capacity to synthesize type I and III collagen fibers, a stimulation with Transforming Growth Factor-β1(TGF-β1) has been performed in culture. TDSCs comply with the expected phenotype of mesenchymal stem cells as defined by ISCT. All the samples and conditions analyzed by flow cytometry were positive for CD105, CD90, CD29, CD44 and negative for MHC-II. Their tenogenic potential is also confirmed by qRT-PCR. TDSCs are metabolically active cells, showing an ultrastructure reflecting high level of proteins synthesis. Moreover, they are able to synthetize collagen fibers under stimulation by TGF-β1. Freshly harvested or cryopreserved TDSCs are involved in the tenogenic pathway and are able to produce an extracellular collagenous network. These properties make them suitable for banking and subsequent clinical use for contributing to tendon repair.