Case report: Equine metacarpophalangeal joint partial and full thickness defects treated with allogenic equine synovial membrane mesenchymal stem/stromal cell combined with umbilical cord mesenchymal stem/stromal cell conditioned medium.
Authors: Reis I L, Lopes B, Sousa P, Sousa A C, Rêma A, Caseiro A R, Briote I, Rocha A M, Pereira J P, Mendonça C M, Santos J M, Lamas L, Atayde L M, Alvites R D, Maurício A C
Journal: Frontiers in veterinary science
Summary
# Editorial Summary A five-year-old show-jumping stallion with severe full and partial-thickness cartilage defects affecting the lateral metacarpal condyle and dorsolateral proximal phalanx was treated with an innovative combination therapy: arthroscopic debridement followed by two intra-articular injections of equine synovial membrane-derived mesenchymal stem/stromal cells (eSM-MSCs) paired with umbilical cord-derived MSC conditioned medium, administered 15 days apart. Following a structured 12-week rehabilitation protocol, the horse demonstrated remarkable clinical improvement with resolution of lameness, pain, and joint effusion, though initial imaging still showed incomplete healing at the metacarpal lesion site, necessitating a second treatment cycle. By completion, imaging confirmed full healing at the proximal phalanx, substantial filling of the osteochondral defect at the metacarpus, and formation of cartilage-like tissue, ultimately enabling the stallion to return to competitive sport. This case illustrates the regenerative potential of MSC-based therapies in addressing refractory articular cartilage damage, likely mediated through paracrine anti-inflammatory and pro-regenerative mechanisms rather than direct cellular integration. For practitioners managing high-motion joint injuries in performance horses, this combination approach warrants consideration as an adjunctive strategy when conventional management plateaus, though further comparative research is essential to establish protocols, optimal dosing intervals, and long-term durability in diverse clinical presentations.
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Practical Takeaways
- •MSC-based regenerative therapy combined with conditioned medium may offer promise for treating full and partial-thickness articular cartilage defects in high-performance horses, though this case required two treatment cycles.
- •Clinical soundness and return to athletic function can occur even when imaging shows incomplete radiographic healing, suggesting functional tissue remodeling continues after treatment.
- •This innovative approach warrants further investigation through controlled trials to establish optimal dosing, timing, and patient selection criteria for clinical adoption.
Key Findings
- •A 5-year-old show-jumping stallion with full and partial-thickness MCj defects was treated with intra-articular injections of equine synovial membrane MSCs combined with umbilical cord MSC conditioned medium, 15 days apart.
- •After initial 12-week rehabilitation, imaging showed incomplete healing of MC3 lesion, requiring a second round of treatment.
- •Following second treatment, the horse achieved clinical soundness and returned to higher-level athletic performance with imaging evidence of lesion absence at P1 and cartilage-like tissue formation at MC3.
- •Combined MSC and MSC conditioned medium therapy demonstrated anti-inflammatory and pro-regenerative effects through paracrine mechanisms for treating full and partial cartilage defects.