Post-exercise Cardiac Troponin-I Concentrations In Saliva: Non-invasive Detection Of Exercise-induced Myocardial Injury With Point-of-care Testing

PURPOSE: To quantify salivary concentrations of cardiac troponin-I (cTnI) in well-trained male runners before (T1), early (T2), 4 h (T3), and 24 h (T4) after exercise. METHODS: Twenty male runners (age: 28 ± 3 years, BMI: 22.33 ± 1.03 kg/m2) with at least three years’ regional-level competition experience were recruited. Based on the pre-participation screening evaluations, all participants were judged to be free of cardiovascular disease (or other limiting conditions). All participants completed the 5-km time-trial around a 400 m athletics track at the Athletics Centre. Participants were encouraged to produce a maximal effort and times were recorded manually using a stopwatch. Unstimulated saliva was collected at T1, T2, T3, and T4. Saliva samples were centrifuged at 3000 rpm for 15 min, and the supernatant was aliquoted. Salivary concentrations of cTnI were measured using a point-of-care immunochromatographic assay. Each measurement was done in duplicate. Assumption of normality was estimated by the Shapiro-Wilk test. Because there was no homogeneity of the variances, within-group differences were examined using the Friedman test, with a Durbin-Conover pairwise post-hoc test. RESULTS: Times to complete the 5 km for the participants were 1084 ± 50 s. Salivary concentrations of cTnI increased at T2 (0.43 ± 0.06 ng/mL) compared to T1 (0.18 ± 0.02 ng/mL), reaching the highest values at T3 (0.62 ± 0.07 ng/mL) with the subsequent return to baseline values at T4 (0.16 ± 0.02 ng/mL). All comparisons were statistically significant (p < 0.05) and are shown in Figure. CONCLUSION: In a sports and exercise medicine setting, quantification of cTnI concentrations in saliva with point-of-care testing may be a useful non-invasive tool in assessing whether exercise-induced increases in cTnI concentrations are transient or there are acutely or chronically elevated cTnI levels. ACKNOWLEDGMENTS: This research was funded by the Russian Science Foundation [project number 23-75-01039]. Supported by: This research was funded by the Russian Science Foundation [project number 23-75-01039].