Intensive cycling training increases serum calprotectin and PTX3 concentrations in professional athletes

BACKGROUND: Physical training induces both inflammatory and metabolic changes in professional athletes. The present cohort study aimed to evaluate serum calprotectin and pentraxin 3 (PTX3) concentrations before and after a high-intensity cycling session in professional athletes. We also aimed to explore their relationship with classical inflammatory and metabolic markers such as white blood cells (WBC), glucose, lactate, uric acid and C-reactive protein (CRP). METHODS: A total of 25 athletes (cyclists and triathletes) participated in the study protocol. Blood was taken from each participant before and immediately after a 2-hour cycling training for glucose, uric acid, calprotectin, PTX3, CRP, complete blood count and lactate measurement. RESULTS: Statistically significant increase after intensive training was found for WBC, neutrophil, mean corpuscular volume, lactate, uric acid, calprotectin and PTX3 concentrations, and a decrease in lymphocyte and eosinophil count when compared to values before training. No statistically significant correlation was found between changes in calprotectin concentration and changes in metabolic and inflammatory biomarkers. For changes in PTX3 concentration, only a poor negative correlation was found between its changes and changes in lymphocyte count. As with calprotectin, no other statistically significant correlation was found between changes in PTX3 concentration and changes in metabolic parameters and other inflammatory biomarkers. CONCLUSIONS: Intensive cycling training leads to significant increase in both serum calprotectin and PTX3 concentration in professional cyclists. This increase is not associated with changes in other inflammation and metabolic biomarkers. Calprotectin and pentraxin 3 could serve as a sensitive, early and sports-related biomarkers of physiological stress.