Clinical Outcomes Following Intra-Articular Administration of Autologous Muscle-Derived Mesenchymal Stem Cells in Horses with Chronic Osteoarthritis: A Prospective Open-Label Study.

Overview

• This study evaluated the safety and effectiveness of injecting a horse’s own muscle-derived mesenchymal stem cells (mdMSCs) directly into joints affected by chronic osteoarthritis (OA).
• The findings suggest that this treatment can reduce lameness and improve joint health with minimal side effects over a 12-week period.

Background

• Osteoarthritis (OA) is a common joint disease in horses causing pain, inflammation, and lameness.
• Mesenchymal stem/stromal cells (MSCs) have regenerative and anti-inflammatory properties, making them a potential therapeutic approach for OA.
• Most prior research has focused on allogeneic (donor-derived) MSCs or treatments combining MSCs with other agents.
• There is limited evidence on using autologous (self-derived) MSCs alone, particularly those derived from muscle tissue (mdMSCs), for equine OA treatment.

Study Design

• This was a prospective open-label clinical study involving 13 horses diagnosed with naturally occurring chronic OA.
• Each horse received a single intra-articular injection of autologous mdMSCs into the affected joint.
• The cell dose was scaled to the joint size: either 1 × 10^6 or 2 × 10^6 cells per joint.
• Assessments were made at baseline (pre-treatment), 6 weeks post-treatment, and 12 weeks post-treatment.

Outcome Measures

• Lameness was evaluated using the standard American Association of Equine Practitioners (AAEP) lameness scale, which grades severity.
• Joint inflammation was scored to monitor any potential inflammatory reactions in response to the treatment.
• A composite total clinical score (TCS) combined lameness and inflammation assessments to provide an overall clinical picture.
• Responder criteria were predefined, likely including thresholds of improvement in lameness scores.

Results

• Clinical scores showed a significant decrease (improvement) at both 6 and 12 weeks compared to baseline.
• Seven out of thirteen horses met the responder criteria, with some achieving complete resolution of lameness.
• The treatment was well tolerated with no serious adverse effects reported.
• Only mild, temporary local reactions (e.g., minor inflammation) were observed and resolved without needing any medical intervention.

Conclusions

• Intra-articular injection of autologous muscle-derived MSCs appears to be a safe and effective stand-alone treatment option for chronic osteoarthritis in horses.
• This suggests an encouraging alternative to allogeneic or combination therapies, potentially minimizing risks of immune reactions or complications.
• These promising results warrant further investigation through larger controlled studies to confirm benefits and optimize treatment protocols.