Urinary candidate biomarkers in an experimental autoimmune myocarditis rat model

Urine is a better source than plasma for biomarker studies, as it can accumulate all changes in the body. Various candidate urinary biomarkers of physiological condition, kidney disease and even brain dysfunction, have been detected in urine; however, urine has rarely been used to reflect cardiac diseases. In this study, urine at day 0, 14, 21 and 28 were collected from the myosin-induced autoimmune myocarditis rat models. The candidate urinary biomarkers were then characterized using the isobaric tandem mass tag labeling approach coupled with offline two-dimensional reverse-phase liquid chromatography and high-resolution mass spectrometry. Compared with controls, forty-six urinary proteins were significantly changed in the myocarditis rats; among them, ten had previously been associated with myocarditis, twelve corresponding gene products had annotated as mainly cardiovascular network genes by the Ingenuity Pathway Analysis, four urinary proteins were validated by western blot, thirteen were reported in previous urine proteome studies of other diseases and twenty-six were reported the first time to be related to myocarditis.

This is the first study to use isobaric tandem mass tag labeling approach in the urine proteome analysis of experimental autoimmune myocarditis. These findings may provide clues for the pathogenesis of myocarditis. And the study showed that urine can be a good source of myocarditis biomarkers.