Suspension of bone marrow-derived undifferentiated mesenchymal stromal cells for repair of superficial digital flexor tendon in race horses.

This study shows that the injection of mesenchymal stromal cells (MSCs), extracted directly from an animal’s bone marrow, can fix partially damaged tendons in racehorses without requiring scaffolds to support the cells.

Overview of the Research

• The research explored the possibility of repairing tendon lesions in racehorses by injecting them with undifferentiated MSCs – a type of cell that has the ability to grow (differentiate) into tenocytes, which are the cells that make up tendons.
• The study was driven by previous experimental attempts which used scaffold carriers to support and position the MSCs in the area of the lesion. In contrast, this study investigated the use of MSCs without the additional support of a scaffold.

Methodology and Findings

• For the study, the researchers isolated MSCs from the bone marrow of the horses and then injected those undifferentiated cells into the damaged sections of the tendons.
• The effectiveness of this treatment was evaluated using ultrasound images of the healed tendons, whether the horses could return to racing, and whether the fibres were properly oriented in the healed tendons.
• Significant clinical recovery was observed in 9 out of 11 horse cases. This suggests that only a small number of undifferentiated MSCs is required to repair the damaged tendons, even without any scaffold support.
• Importantly, because only undifferentiated cells were used, there were no instances of misplaced bone cell development (referred as ectopic bone deposition) in the tendons, which could typically happen when differentiated cells are used.

Conclusions and Recommendations

• The research concluded that using horse’s own (autologous) MSCs is a safe and effective therapeutic method for treating partially (not full-thickness) damaged tendons.
• Adequate numbers of these cells could be harvested for transplant in all but one case, showing that the technique could be used widely in treating tendon injuries in horses.