Changes in Acute Phase Response Biomarkers in Racing Endurance Horses

Abstract

This study aimed to evaluate if exercise-induced acute phase response (APR) occurs in endurance horses in response to the race. The study included 23 horses competing in an endurance competition with a successfully passed clinical examination before the race. Blood samples were collected before the start and within 30 min after the end of the race. Haematological and biochemical tests were performed and correlated to acute phase biomarkers changes. Values of calprotectin and haptoglobin (Hp) decreased after the races compared to values before, while concentrations of ceruloplasmin and albumin recorded a significant increase. Greater changes in calprotectin values were noted in Arabian horses compared to other breeds. Values of Hp showed a significantly greater decrease after longer races. Based on study results, endurance racing induces APR in horses characterised by significant changes in selected acute phase biomarkers. More pronounced changes were noted at races with higher average speeds, suggesting the need for thorough horse monitoring during exhausting races.

Blood‐based assessment of oxidative stress, inflammation, endocrine and metabolic adaptations in eventing horses accounting for plasma volume shift after exercise

“…However, when considering the plasma shift–adjusted values, it becomes clear that the alleged increase is in fact much smaller and has no relevance. Haemolysis after exercise can be caused by mechanical damage to the erythrocytes or a low oxygen content during exercise and is also suspected in endurance horses (Mihelic et al., 2022). Mechanically induced or cytokine‐induced cell damage in the form of an inflammatory reaction in the musculature (Nieman et al., 2005; Smith, 2000) could be the cause of the observed signs of haemolysis.…”

“…Other studies have also shown that there is an exercise‐induced increase in liver enzymes without liver disease (McGowan 2008). In endurance horses, the increase in GGT is not as big, but the increase in AST is even bigger than in eventing horses (Mihelic et al., 2022).…”

“…For WBC, there are at least three different causes that can lead to the observed slight increase after the end of exercise. First, muscle microdamage could lead to local inflammatory responses (Horohov et al., 2012; Mihelic et al., 2022). Second, increased sympathetic activity due to emotional stress could lead to leukocyte activation (Muñoz et al., 1999; Mihelic et al., 2022).…”

“…First, muscle microdamage could lead to local inflammatory responses (Horohov et al., 2012; Mihelic et al., 2022). Second, increased sympathetic activity due to emotional stress could lead to leukocyte activation (Muñoz et al., 1999; Mihelic et al., 2022). Third, an increase in WBC may also arise from splenic contraction (Carakostas et al., 1981; Muñoz et al., 1999; McGowan, 2008).…”

Dynamic Correlation between Platelet Aggregation and Inflammatory-like State in Athlete Horses

“…In horses, the CRP is a moderate APP and an increase in its concentration has been reported after castration, in enteritis, arthritis, laminitis and induced inflammation [9]. A reaction analogous to the APR in inflammatory conditions has also been reported after exercise in humans [10,11] and in athletic horses [12,13]. As a matter of fact, physical exercise induces various stress responses and metabolic adaptations.…”