Bone Marrow MSC Secretome Increases Equine Articular Chondrocyte Collagen Accumulation and Their Migratory Capacities

Abstract

Equine osteoarthritis (OA) leads to cartilage degradation with impaired animal well-being, premature cessation of sport activity, and financial losses. Mesenchymal stem cell (MSC)-based therapies are promising for cartilage repair, but face limitations inherent to the cell itself. Soluble mediators and extracellular vesicles (EVs) secreted by MSCs are the alternatives to overcome those limitations while preserving MSC restorative properties. The effect of equine bone marrow MSC secretome on equine articular chondrocytes (eACs) was analyzed with indirect co-culture and/or MSC-conditioned media (CM). The expression of healthy cartilage/OA and proliferation markers was evaluated in eACs (monolayers or organoids). In vitro repair experiments with MSC-CM were made to evaluate the proliferation and migration of eACs. The presence of nanosized EVs in MSC-CM was appraised with nanoparticle tracking assay and transmission electron microscopy. Our results demonstrated that the MSC secretome influences eAC phenotype by increasing cartilage functionality markers and cell migration in a greater way than MSCs, which could delay OA final outcomes. This study makes acellular therapy an appealing strategy to improve equine OA treatments. However, the MSC secretome contains a wide variety of soluble mediators and small EVs, such as exosomes, and further investigation must be performed to understand the mechanisms occurring behind these promising effects.

Effect of pro-inflammatory cytokine priming and storage temperature of the mesenchymal stromal cell (MSC) secretome on equine articular chondrocytes

“…Some studies have already demonstrated the potential of MSCderived secretome in cartilage regeneration and, consequently, their usefulness for OA therapy (Cosenza et al, 2017;Velot et al, 2021). Recently, we showed that an unstimulated BM-MSC secretome promotes collagen production in equine articular chondrocytes (eACs) and increases their migratory capacities (Contentin et al, 2022). Interestingly, intra-articular injections of the MSC secretome in an equine model of joint inflammation show anti-inflammatory effects comparable to those observed with the direct injection of MSCs (Kearney et al, 2022).…”

“…However, low production yields and lack of disease specificity are limitations that prevent the use of MSC secretome-based therapy to its full capacity (Chen et al, 2022). Furthermore, when eACs are cultured with the naïve MSC secretome, the neosynthesized ECM contains type I collagen, suggestive of fibrocartilage formation (Contentin et al, 2022). Because the MSC-secretome composition highly depends on the environment that the MSCs develop in, it is possible to enhance the secretion of MSCs for therapeutic applications thanks to several methods (Jammes et al, 2023).…”

Equine osteoarthritis: Strategies to enhance mesenchymal stromal cell-based acellular therapies

“…To date, only a few studies have demonstrated the therapeutic potential of eMSC-EVs in the context of horse OA. Using an in vitro cartilage organoid model, our research group has already demonstrated the pro-anabolic potential of eMSC-conditioned media (CM) and the presence of exosomes in eMSC-CM (28). The CM corresponds to the medium in which cell were cultured, hence it contains components that had been secreted by the cells.…”

“…It has already been proven that the unstimulated eMSC secretome can enhance the equine articular chondrocyte phenotype and increase their migratory capacity (28,30). Nevertheless, therapeutic capacities of naive MSCs developing in a healthy environment have not been optimized.…”

Strategies for Cartilage Repair in Osteoarthritis Based on Diverse Mesenchymal Stem Cells‐Derived Extracellular Vesicles

“…Gradually, EVs are considered to be the latest candidates for cartilage injury, and study has demonstrated that EVs show excellent potential in cartilage repair 13 . A mass of studies have confirmed the safety and effectiveness of EVs for the treatment of cartilage defects in small animals, although their utility in large animal models is less well established In a study based on OA in equine chondrocytes, MSCs‐EVs (less than 200 nm in diameter) were observed to be more effective than MSCs in increasing chondrocyte proliferation and migration to maintain the equine chondrocytes phenotype, suggesting that MSCs‐EVs promoted cartilage repair and delayed the progression of OA 14 . Furthermore, a study demonstrated superior outcomes using EVs combined with hyaluronic acid over hyaluronic acid alone in treating cartilage defects in micropigs, with improvements noted in MRI scores, histology, biomechanics, and bone mass.…”