Evaluation of intra-articular mesenchymal stem cells to augment healing of microfractured chondral defects.

This research evaluates the impact of using bone marrow-derived stem cells to assist in the healing process of microfractured bones, specifically in the knee, when compared to healing with microfracture alone. The results suggest that while there isn’t a significant clinical difference between the two groups, using stem cells does enhance the quality of cartilage repair, showing potential benefits for clinical use.

Research Methodology

• The researchers conducted this experiment using ten horses. They created defects on both medial femoral condyles of the horse’s stifle joint (a structure similar to the human knee).
• The defects were then cleaned and microfractured. After one month, one randomly chosen medial femorotibial joint in each horse was injected with either a combination of 20 × 10(6) bone marrow-derived mesenchymal stem cells (BMSCs) and 22 mg of hyaluronan, or 22 mg of hyaluronan alone.
• Post-treatment, the horses were confined for 4 months, with a progressively increasing exercise regime starting two weeks post-injection. This included strenuous treadmill exercise designed to simulate race training up until the end of the study at 12 months.
• Horses underwent clinical and radiographic examinations every two months and a second-look arthroscopy at 6 months.
• The experimentation concluded at 12 months, with further analysis of the affected joints via magnetic resonance imaging and a variety of examinations including gross, histologic, histomorphometric, immunohistochemical, and biochemical analysis.

Findings

• While there were no significant clinical improvements observed in the joints injected with BMSCs, the researchers noted a significant increase in the firmness of the repair tissue and a possible improvement in the overall repair tissue quality in these joints compared to those treated with hyaluronan alone.
• Immunohistochemical analysis revealed significantly greater levels of aggrecan (a proteoglycan that plays an essential role in cartilage structure and function) in the repair tissue that was treated with BMSCs.
• No other significant treatment effects were found by the researchers.

Conclusion

• Although no clear clinical or histological differences were determined between the two groups, this study confirms that the use of intra-articular BMSCs can improve the quality of cartilage repair due to increased aggrecan content and tissue firmness.
• The results of the study suggest that clinical use of BMSCs in conjunction with microfracture of cartilage defects could potentially be beneficial.