Short‐term welfare assessment of a single ultrasound‐guided adipose tissue aspiration in standing sedated horses

Summary Background Adipose tissue‐derived mesenchymal stem cells (AT‐MSCs) are entering the market of orthobiologics suitable for managing musculoskeletal disorders in horses, due to their accessibility and reparative capacity. Ethical considerations in developing allogeneic products require a low‐morbidity approach to tissue harvest. The impact of adipose tissue collection on a donor's welfare is a key regulatory concern. Although tumescent ultrasound‐guided lipoaspiration is classified as a minimally invasive procedure, its effects on donor welfare have not yet been systematically assessed or documented. Objectives To evaluate the feasibility and short‐term welfare implications of a single ultrasound‐guided lipoaspiration for harvesting AT‐MSCs in standing sedated horses. Study design Prospective observational study. Method Bilateral lipoaspiration from the gluteal‐semitendinosus regions was carried out on four healthy, sedated horses using tumescent fluid. The procedure's duration, macroscopic quality of the lipoaspirate, intraoperative complications and signs of discomfort were recorded. Postoperatively, the horses were monitored for 1 week for surgical site complications, pain and lameness. Series of serum amyloid A (SAA) measurements facilitated assessment of the inflammatory response. A post‐mortem evaluation of surgical site inflammation, oedema and subcutaneous haemorrhage was carried out. Results The procedure was well tolerated by all horses, with most collected aliquots being of good quality; only three out of eight had moderate blood contamination. Transient lameness severity remained below 2/8 and returned to baseline within the study period. Incision sites healed with a good cosmetic outcome. Equine pain scores never exceeded 2/30, and SAA levels stayed below reference levels. Post‐mortem assessments revealed only minor localised inflammatory reactions in the surgical area. Main limitations Terminal study design and a small sample size. Conclusion Lipoaspiration was well tolerated by standing sedated horses, resulting in no to minimal pain, lameness and inflammatory response. The described method for performing a single lipoaspiration for harvesting AT‐MSCs can be considered ethically acceptable.