Resting concentrations of cardiac troponin I in fit horses and effect of racing.

This research article explores the resting values for cardiac troponin I in healthy horses of different breeds, and how those levels are affected by the racing. Cardiac troponin I is a marker of cardiac injury and its study might prove useful when investigating horses with suspected heart disease that have recently undertaken strenuous exercise.

Background

• The premise that drove this research is the use of cardiac troponin I (cTnI) as an indicator of myocardial damage in humans.
• The said protein is highly conserved among different species and has recently caught interest as a potential marker for cardiac injury in horses.
• There have been reported cases where increased levels of cTnI have been associated with both endurance and short-term strenuous treadmill exercise in horses.
• What remains unverified, however, is the effect of real racing conditions on the levels of cTnI.

Methods

• The study involved collecting blood samples for plasma cTnI analysis from 67 Standardbred racehorses, 34 Thoroughbred racehorses, and 35 Warmblood dressage horses while they were resting.
• In addition to that, blood samples were also collected before and after racing from a cohort of 22 Standardbred racehorses and 6 Thoroughbred racehorses for comparison.

Results

• Except for one, all other horses exhibited resting plasma cTnI concentrations less than 0.022 microg/L.
• A mild increase in cTnI concentrations were recorded in some horses between 1-2 hours post-race and 10-14 hours post-race. The specific counts were 1 out of 17 Standardbreds and 2 out of 6 Thoroughbreds for the 1-2 hours interval, and 4 out of 21 Standardbreds and 1 out of 6 Thoroughbred for the 10-14 hours interval.

Conclusions

• The study concluded that resting cTnI concentrations in horses are generally low.
• It was noticed that mildly elevated cTnI concentrations can be detected in some horses between 1-14 hours after racing.
• This discovery could be significant when examining horses suspected of having cardiac disease, especially if they have recently performed strenuous exercise.