Donor-Matched Comparison of Chondrogenic Potential of Equine Bone Marrow- and Synovial Fluid-Derived Mesenchymal Stem Cells: Implications for Cartilage Tissue Regeneration

Abstract

Mesenchymal stem cells (MSCs) have been demonstrated to be useful for cartilage tissue regeneration. Bone marrow (BM) and synovial fluid (SF) are promising sources for MSCs to be used in cartilage regeneration. In order to improve the clinical outcomes, it is recommended that prior to clinical use, the cellular properties and, specifically, their chondrogenic potential must be investigated. The purpose of this study is to compare and better understand the in vitro chondrogenic potential of equine bone marrow-derived mesenchymal stem cells (BMMSCs) and synovial fluid-derived mesenchymal stem cells (SFMSCs) populated from the same equine donor. BM- and SF-derived MSCs cultures were generated from five equine donors, and the MSCs were evaluated in vitro for their morphology, proliferation, trilineage differentiation, and immunophenotyping. Differences in their chondrogenic potentials were further evaluated quantitatively using glycosaminoglycan (GAG) content and via immunofluorescence of chondrogenic differentiation protein markers, SRY-type HMG box9, Aggrecan, and collagen II. The BMMSCs and SFMSCs were similar in cellular morphology, viability, and immunophenotype, but, varied in their chondrogenic potential, and expression of the key chondrogenic proteins. The SFMSCs exhibited a significant increase in GAG content compared to the BMMSCs (P < 0.0001) in three donors, suggesting increased levels of chondrogenesis. The expression of the key chondrogenic proteins correlated positively with the GAG content, suggesting that the differentiation process is dependent on the expression of the target proteins in these three donors. Our findings suggest that even though SFMSCs were hypothesized to be more chondrogenic relative to BMMSCs, there was considerable donor-to-donor variation in the primary cultures of MSCs which can significantly affect their downstream application.

Repair of articular cartilage defects with intra-articular injection of autologous rabbit synovial fluid-derived mesenchymal stem cells

“…Furthermore, the SF-MSCs possess highly immunosuppressive properties in vivo [ 7 ]. Compared to the BM-MSCs and synovium-derived mesenchymal stem cells (SM-MSCs), SF-MSCs prefer differentiation into functional chondrocytes and secrete a large amount of extracellular matrix, making them an excellent alternative cell source for cartilage regenerative therapy [ 42 – 44 ].…”

Xenogenic Implantation of Equine Synovial Fluid-Derived Mesenchymal Stem Cells Leads to Articular Cartilage Regeneration

“…BMMSC and SFMSC cultures have been previously generated and characterized in our laboratory [ 16 , 20 ]. Cryopreserved passage 3 MSCs from one specific equine donor were used in all the experiments in this study.…”

“…However, recent reports have suggested that synovial fluid-derived MSCs (SFMSCs) may have the potential and hence may be a better source to regenerate cartilage defects, such as those involving chondral and osteochondral defects [ 14 ]. Synovial fluid-derived MSCs present an attractive cell source because they can be harvested relatively in a minimally invasive manner from synovial fluid and retain a particularly high capacity for chondrogenic differentiation and proliferation compared with MSCs obtained from other tissues, such as bone marrow or periosteum [ 9 , 15 , 16 ].…”

“…We previously reported a donor-matched comparison of bone marrow and synovial fluid-derived MSCs from 5 healthy mixed breed horses (age 8–13 years) with respect to their in vitro properties of proliferation, expression of mesenchymal stem cell protein markers, and chondrogenic potential. Out of the 5 donors, we identified one in which the SFMSCs were similar to the BMMSCs in their proliferation and expression of CD29, CD44, and CD90 but exhibited a significantly higher in vitro chondrogenesis [ 16 ]. Based on the in vitro results, we hypothesized that the SFMSCs will have a significantly higher chondrogenic potential in vivo as well.…”

Synovial Fluid Mesenchymal Stem Cells for Knee Arthritis and Cartilage Defects: A Review of the Literature

“…Moreover, it was recently demonstrated that SF-MSCs possess higher chondrogenic capacity and cartilage repair potential than BM-MSCs. 11,19,20 Thus, it has been hypothesized that SF-MSCs could be a better therapeutic option for anti-inflammation autologous transplantation for cartilage regeneration. 10 Potentially isolated multipotent MSCs from the SF could be used as an autologous therapy for osteoarthritic conditions or cartilage defects.…”