ABSTRACT
REASONS FOR PERFORMING STUDY: Autologous platelet concentrates (APCs) are being used increasingly in horses to enhance regeneration in tissues that have poor natural healing capabilities. Numerous APC systems, which are based on different preparation techniques and were originally developed for human patients, are now routinely used in equine cases. However, preliminary process validation and adequate in vitro biochemical characterisation of most of these systems do not exist for horses. OBJECTIVES: To compare haematological findings and growth factor concentrations of equine APCs obtained with 4 commercially available systems and a noncommercial double-centrifugation technique. STUDY DESIGN: Nonrandomised in vitro experiment. METHODS: Blood samples from 6 horses were processed to produce APCs using one equine-specific filtration-based and 4 different centrifugation-based techniques. Platelet, leucocyte, platelet-derived growth factor-BB and transforming growth factor-ß1 concentrations were measured in all APCs, and their respective enrichment factors were compared. RESULTS: Mean platelet concentration increased in all systems in comparison to baseline; however, the mean enrichment factor, which ranged from 130% to 527% depending on the APC, was statistically significant in only 2 products. One method reduced total leucocyte counts to 9% of the baseline value, while the others had a mean fold increase varying from 116 to 663% of the baseline. Differential leucocyte count also differed between the products. Moreover, the various systems had significantly different mean growth factor enrichments (184-1255% for platelet-derived growth factor-BB and 93-560% for transforming growth factor-ß1 ). CONCLUSIONS: Haematological and biochemical characteristics varied markedly among 5 techniques used in the field to produce APCs in horses. These discrepancies could have an impact on clinical outcomes, and further studies are needed to determine their influence on the quality of tissue regeneration. Clinicians should not rely on the manufacturers' data relating to human patients to select the most appropriate method for horses.
