Urethral reconstruction using a preputial mucosa free flap and autologous Mesenchymal Stromal Cells in a male alpaca (Vicugna pacos)

: Like small ruminants, alpacas are prone to urethral obstruction, commonly caused by urolithiasis. Surgical intervention, such as perineal urethrostomy, is often necessary, though recurrent strictures and impaired healing pose significant challenges. A 2-year-old, 40 kg neutered male alpaca was referred for severe urinary retention and hemorrhage following an unsuccessful previous perineal urethrostomy. Due to extensive tissue damage observed after the previous urethrostomy, a conventional surgical approach was not viable, leading to the decision to reconstruct the urethra using a free preputial mucosal flap seeded with autologous mesenchymal stromal cells (MSCs). Cells were isolated from subcutaneous adipose tissue, expanded in vitro and characterized. Two months post-initial surgery, urethral reconstruction was performed, and MSCs were applied both within the graft and as a topical gel. Postoperatively, the alpaca recovered well, with proper wound healing, no signs of infection, and no recurrence of urethral stricture. In this case report, for the first time in alpacas, MSC-seeded graft for urethral reconstruction was used. The successful outcome highlights the potential of MSC-based therapies in veterinary regenerative medicine, particularly for addressing complex urethral defects and improving long-term surgical success. Further studies are needed to explore the broader applications of MSCs in New World camelid surgery.