Chondrogenic re-differentiation potential of chondrocytes after monolayer culture: Comparison between osteoarthritis and young adult patients

Purpose: Monolayer passage of chondrocytes results in dramatic phenotypic changes. This “de-differentiation” is expected to restore the chondrogenic properties such as “re-differentiation” in autologous chondrocyte implantation (ACI). The purpose of this study was to compare the chondrogenic re-differentiation potential of chondrocytes, from osteoarthritis (OA) patients and young adult patients, after monolayer culture. Methods: Chondrocytes from five old patients with knee OA (OAC) and five young patients with recurrent shoulder dislocation (non-OAC) were used. The chondrocytes from passages 1 to 3 were analyzed for the expression of cell surface markers (CD73, CD90, CD105, and CD44) by flow cytometric analysis. Chondrocytes of passage 4 were cultured as pellets for re-differentiation and evaluated histologically. Real-time PCR were performed to measure the chondrogenic related genes transcriptional levels. Results: OAC and non-OAC had comparable positive ratios for CD44, CD73, CD90, and CD105. The expression of CD105 was upregulated from passage 1 to passage 3 in OAC, and it increased at the same level as in non-OAC during passage 2 and 3. The expression of COL2 decreased from passage 1 to passage 3 in both the groups. There were no statistical differences in the Bern Scores between OAC and non-OAC. Conclusion: The chondrocytes from OA patients and young adult patients had chondrogenic re-differentiation potential. The changes in cell surface markers and chondrogenic related genes showed similarity for both the groups. Our findings suggest that OAC can become the cell source for ACI