Serum skeletal troponin I following inspiratory threshold loading in healthy young and middle-aged men
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The purpose of this study was to determine if serum levels of skeletal troponin I (sTnI, fast and slow isoforms) could provide a sensitive marker of respiratory muscle damage in healthy humans subjected to inspiratory loads. To accomplish this, we studied healthy, young (27 ± 2 years, Mean ± SEM, n = 5) and middle-aged (55 ± 5, n = 5) men to (1) determine the magnitude, pattern, and time course of the presence of sTnI in the serum after a single 60 min bout of inspiratory threshold loading [ITL, ~70% of maximal inspiratory pressure (MIP)], (2) determine the distribution and magnitude of DOMS after loading, and (3) compare fast and slow sTnI levels, and their relationship to other markers/indices of muscle injury including delayed onset muscle soreness (DOMS), serum creatine kinase (CK) levels, and force generating capacity of the respiratory muscles [MIP and maximal expiratory pressure (MEP)]. There was a 24 ± 4 and 27 ± 3% increase in fast sTnI 1 hour (p < 0.01) and 3 days (p < 0.01) after ITL. Slow sTnI was elevated by 24 ± 10% (p < 0.05) 4 days postITL. Other indices of respiratory muscle injury such as CK, MIP and MEP did not show a difference in mean data following ITL; DOMS was slightly but significantly increased following ITL. Our results suggest that sTnI has superior sensitivity compared to other biomarkers/indices of skeletal muscle injury. Future studies examining the impact of respiratory muscle injury with ventilator weaning should consider using sTnI as a sensitive marker of skeletal muscle injury.
KeywordsBiomarker Diaphragm Exercise Hypoxia Muscle
We thank our subjects for volunteering their time to complete this research. Primary monoclonal antibody, MYNT-S, was provided to us courtesy of N. Matsumoto. We extend gratitude for the technical and administrative support provided by Ms. Jennifer Rurak and Dr. Cristiane Yamabayashi. This research was supported by a grant-in-aid from the British Columbia Lung Association. G.E. Foster was supported by a fellowship from the Natural Sciences and Engineering Research Council of Canada. A.W. Sheel was supported by a New Investigator award from the Canadian Institutes of Health Research.
- American Thoracic Society Task Force (1995) Standardization of Spirometry, 1994 Update. American Thoracic Society. Am J Respir Crit Care Med 152:1107–1136Google Scholar
- Institute/NCCLS. CaLS (2004) Procedures for the Handling and Processing of Blood Specimens: Approved GuidelineGoogle Scholar
- Quanjer PH, Tammeling GJ, Cotes JE, Pedersen OF, Peslin R, Yernault JC (1993) Lung volumes and forced ventilatory flows. Official statement of the European respiratory society. Eur Respir J 6:5–40Google Scholar
- Vogiatzis I, Athanasopoulos D, Habazettl H, Aliverti A, Louvaris Z, Cherouveim E, Wagner H, Roussos C, Wagner PD, Zakynthinos S (2010) Intercostal muscle blood flow limitation during exercise in chronic obstructive pulmonary disease. Am J Respir Crit Care Med 182:1105–1113PubMedCrossRefGoogle Scholar
- Willoughby DS, Vanenk C, Taylor L (2003) Effects of concentric and eccentric contractions on exrecise-induced muscle injury, inflammation, and serum IL-6. J Exerc Physiol 2003:8–15Google Scholar