Use of Autologous Conditioned Serum (ACS) for Osteoarthritis Treatment in Horses: A Systematic Review of Clinical Data

Simple Summary Regenerative medicine has emerged as a widely employed therapy for osteoarthritis (OA) and tendon lesions in both veterinary and human medicine. Despite numerous studies having been conducted, definitive outcomes remain elusive. This study seeks to comprehend the evolution of regenerative medicine from in vitro to in vivo studies, focusing on the effectiveness of Autologous Conditioned Serum (ACS) products in treating OA. The study only took into consideration clinical trials using ACS. All relevant articles published in the last two decades have been scrutinized. Despite a plethora of in vitro studies, the positive outcomes of autologous conditioned serum (ACS) products in in vivo settings have not been conclusively demonstrated. Notably, only six studies met the inclusion criteria. One study incorporated a control group, whereas the other five clinical trials were conducted without a control group. Consequently, there exists no definitive evidence supporting the efficacy of ACS therapy. This underscores the need for more controlled trials to draw a firm conclusion about the effectiveness of ACS as an OA treatment in horses, a conclusion that would have potential implications for humans. The current scarcity of controlled studies highlights the imperative for further research to enhance our understanding of ACS therapy's therapeutic potential in addressing osteoarthritis.Abstract The utilization of Autologous Conditioned Serum (ACS) for treating osteoarthritis (OA) in horses has seen a notable increase in recent years. In vitro studies have consistently identified ACS as a promising therapy for OA joints, contributing to its growing popularity in OA treatment. Despite this, there is a noticeable absence of systematic reviews focused solely on the clinical data of OA patients treated with ACS, excluding the in vitro perspective. This study aims to address this gap by systematically reviewing the latest literature, concentrating solely on clinical data in in vivo studies to evaluate the efficacy of ACS in OA lesions. All clinical studies involving ACS treatments for horses with OA were included in the assessment. Surprisingly, only six trials met the inclusion criteria for this systematic review. The results indicate that the majority of the considered articles support the use of ACS as a treatment for horses, albeit with a control group provided in only one study. However, the absence of a control group and the exclusion of histological evaluation diminish the validity of the majority of clinical research. While several studies suggest a beneficial effect of ACS on OA horses without significant adverse effects, this systematic review affirms that there is no definitive evidence for its effectiveness. Therefore, further investigation of the efficacy of ACS products as a treatment for OA is warranted, emphasizing the need for more controlled trials. Poorly designed and biased studies, lacking blinding or control and adopting inadequate outcome measures, may favor positive results and, thus, necessitate a more rigorous approach to validate the efficacy of ACS in OA treatment.