Serum Phosphorylated Neurofilament Heavy Subunit Levels and its Association with the Risk for Catastrophic Injury in Thoroughbred Racehorses.

This study explored whether the presence of phosphorylated neurofilament heavy chain (pNF-H), a protein released due to neuron damage, in the blood could indicate a higher risk of severe musculoskeletal injuries in Thoroughbred racehorses. However, the research found no significant correlation between pNF-H levels and injury risk.

Study Objective and Methodology

• The primary objective of this study was to investigate the relationship between the serum levels of a specific protein called phosphorylated neurofilament heavy chain (pNF-H) and the occurrence of catastrophic musculoskeletal injuries (cMSI) in Thoroughbred horses.
• The researchers conducted a case-control study where they compared the serum pNF-H levels between clinically healthy Thoroughbred horses (controls) and those that have suffered catastrophic injuries (cases).
• Injured and healthy horses were tested for their respective pNF-H levels using blood samples. These samples were examined using a specific enzyme-linked immunosorbent assay kit.

Findings and Implications

• In the study population of 343 horses, no significant difference was found between the pNF-H serum concentration levels of the healthy subjects and those that were injured. These findings led to former speculations of a potential association between pNF-H levels and catastrophic injury risk in racehorses.
• Interestingly, a correlation was noted between the number of lifetime starts a horse has had and its resulting concentration of pNF-H within injured horses. This indicates that the total lifetime starts might provide a measure for multiple risk factors relating to the cumulative load of exercise during a racehorse’s career.
• The study also showed that injured horses had higher serum concentrations of pNF-H while training than while racing. This suggests that injury potential might be higher during training than racing contexts, shedding light on the importance of careful monitoring during these phases.
• However, overall, the researchers concluded that measuring pNF-H serum concentrations in Thoroughbred racehorses does not support the hypothesis that subclinical neurological injuries or conditions heighten the risk of catastrophic injury during their careers, challenging an existing belief in the equine research community.