Inflammation affects the viability and plasticity of equine mesenchymal stem cells: possible implications in intra-articular treatments

Abstract

Mesenchymal stem cells (MSCs) are gaining relevance for treating equine joint injuries because of their ability to limit inflammation and stimulate regeneration. Because inflammation activates MSC immunoregulatory function, proinflammatory priming could improve MSC efficacy. However, inflammatory molecules present in synovial fluid or added to the culture medium might have deleterious effects on MSCs. Therefore, this study was conducted to investigate the effects of inflammatory synovial fluid and proinflammatory cytokines priming on viability and plasticity of equine MSCs. Equine bone marrow derived MSCs (eBM-MSCs) from three animals were cultured for 72 h in media supplemented with: 20% inflammatory synovial fluid (SF); 50 ng/mL IFN-γ and TNF-α (CK50); and 20 ng/mL IFN-γ and TNF-α (CK20). Proliferation assay and expression of proliferation and apoptosis-related genes showed that SF exposed-eBM-MSCs maintained their viability, whereas the viability of CK primed-eBM-MSCs was significantly impaired. Tri-lineage differentiation assay revealed that exposure to inflammatory synovial fluid did not alter eBM-MSCs differentiation potential; however, eBM-MSCs primed with cytokines did not display osteogenic, adipogenic or chondrogenic phenotype. The inflammatory synovial environment is well tolerated by eBM-MSCs, whereas cytokine priming negatively affects the viability and differentiation abilities of eBM-MSCs, which might limit their in vivo efficacy.

The Potential of Mesenchymal Stem Cells to Treat Systemic Inflammation in Horses

“…The effect of TGF-β2 was dependent on the baseline expression of MHC and donor animals (44). Further in vitro evidence suggests that cytokine priming has a negative impact on the MSCs viability and differentiation when compared to MSCs primed in an inflammatory synovial fluid (45).…”

Assessment of effectiveness and safety of repeat administration of proinflammatory primed allogeneic mesenchymal stem cells in an equine model of chemically induced osteoarthritis

“…The effects of the cytokine priming on equine BM-MSC immunomodulatory and immunogenic profiles, as well as on their viability and differentiation potential, were already described by our group, as those were the same cells than the used in the present study. Briefly, MSC viability was well preserved after proinflammatory priming and under culture with inflammatory synovial fluid (SF) [ 17 , 39 ], as shown by appropriate proliferation, absence of changes in the BAX/BCL-2 ratio and lack of DNA damage. Furthermore, immunomodulatory profile was upregulated in MSC-primed compared to MSC-naïve.…”

Galectin-1 and galectin-3 expression in equine mesenchymal stromal cells (MSCs), synovial fibroblasts and chondrocytes, and the effect of inflammation on MSC motility

“…Future studies may need to evaluate MSC galectin protein expression at longer intervals following inflammatory cytokine exposure to confirm that galectin protein expression is not changing significantly. In addition, although the concentrations of pro-inflammatory cytokines tested were similar to those used in prior studies [ 43 , 62 ], it is likely that the concentrations used in this study are much higher than those found in naturally occurring equine OA [ 50 ].…”