Preliminary insights into temporal expression patterns of α10β1, α5β1, and α2β1 integrins in freshly isolated chondrocytes: potential impacts on cartilage repair strategies

Autologous chondrocyte implantation is a cell-based therapeutic strategy for cartilage repair. This strategy is limited by the dedifferentiation of chondrocytes during culturing. Integrins, particularly α10β1, have emerged as potential markers for selecting chondrocytes with enhanced chondrogenic capacity. This study aims to explore the expression patterns of α10β1/CD11c+CD29, α5β1/ CD49e+CD29, and α2β1/ CD49b+CD29 integrins in freshly isolated chondrocytes, thus potentially providing alternative strategies in improving ACI outcomes. Cartilage samples were collected from three osteoarthritic knee joints after obtaining consent. Chondrocytes were isolated via enzymatic digestion and assessed via fluorescence-activated cell sorting for integrin expressions CD11c+CD29+, CD49e+CD29+, and CD49b+CD29+ immediately and at specific time points (0, 20-, 40-, 60-, 90-, and 120-minutes post-isolation). Flow cytometry analysis of freshly isolated chondrocytes showed that CD11c+CD29+ expression was high (79.22±6.73%) and progressively and significantly declined (P<0.01), reaching near-zero levels by 120 minutes. CD49e+CD29+ maintained stable expression (91.67±3.34%) throughout the time course, whereas CD49b+CD29+ decreased by 60 minutes. This study highlights the rapid dedifferentiation observed with chondrocytes and, particularly, the CD11c+CD29+ levels, a critical collagen-binding receptor with a high affinity for collagen type II, the primary structural protein in cartilage. If there is a need to use sorting to identify and obtain these cells which potentially will have a higher capacity for chondrogenesis, one must sort these cells as soon as they are released. Future research focusing on α10β1 expression and its impact on cartilage repair could offer valuable insights into developing more efficacious cell-based therapeutics for cartilage pathologies.