Anti-signal recognition particle antibodies induce cardiac diastolic dysfunction via oxidative stress injury.

Objectives: Anti-signal recognition particle (SRP) antibodies, markers of immune-mediated necrotising myopathy, are reportedly related to cardiac involvement; however, whether they are pathogenic to the myocardium remains unclear. We aimed, therefore, to explore the pathogenicity of anti-SRP antibodies against the myocardium through in vivo and in vitro studies. Methods: Total immunoglobulin G (IgG), purified from patients with positive anti-SRP antibodies, was passively transferred into C57BL/6 mice. Cardiac function was evaluated via echocardiography and the ventricular pressure-volume loop; cardiac histological changes were analysed using haematoxylin-eosin staining, picrosirius red staining, immunofluorescence and immunohistochemistry. Additionally, reactive oxygen species (ROS) formation was evaluated by dihydroethidium (DHE) staining; mitochondrial morphology and function were evaluated using transmission electron microscopy and seahorse mitochondrial respiration assay, respectively. The myositis cohort at our centre was subsequently reviewed in terms of cardiac assessments. Results: After the passive transfer of total IgG from patients with positive anti-SRP antibodies, C57BL/6 mice developed significant left ventricular diastolic dysfunction (LVDD). Transcriptomic analysis and corresponding experiments revealed increased oxidative stress and mitochondrial damage in the hearts of the experimental mice. Cardiomyocytes exposed to anti-SRP-specific IgG, however, recovered normal mitochondrial metabolism after treatment with N-acetylcysteine, an ROS scavenger. Moreover, patients positive for anti-SRP antibodies manifested worse diastolic but equivalent systolic function compared to their counterparts after propensity score matching. Conclusion: Anti-SRP antibodies may play a pathogenic role in the development of LVDD by promoting ROS production and subsequent myocardial mitochondrial impairment. The inhibition of oxidative stress was effective in reversing anti-SRP antibody-induced LVDD.

The use of high-sensitivity cardiac troponin I in assessing cardiac involvement and Disease prognosis in idiopathic inflammatory myopathy.

OBJECTIVES: Cardiac involvement is one of the most serious complications of idiopathic inflammatory myopathy (IIM) that indicates poor prognosis. However, there is a lack of effective biomarkers for the identification of cardiac involvement and the prediction of prognosis in IIM. Here, we aimed to explore the value of different cardiac biomarkers in IIM patients. METHODS: A total of 142 IIM patients in the Department of Rheumatology and Immunology, Ruijin Hospital from July 2019 to October 2022 were included in this study. The clinical characteristics, laboratory tests, treatments and prognosis were recorded. The disease activity was assessed according to the core set measures. The correlations of the serum cardiac biomarkers levels with disease activity were analyzed by the Spearman correlation test. Risk factors for cardiac involvement were evaluated by multivariate logistic regression analysis. RESULTS: Higher high-sensitivity cardiac troponin I (hs-cTnI) levels were associated with cardiac involvement (n = 41) in IIM patients [adjusted OR 7.810 (95% CI: 1.962-31.097); p = 0.004], independent of other serum cardiac biomarkers. The abnormal hs-cTnI had the highest AUC for distinguishing of cardiac involvement in IIM patients (AUC = 0.848, 95% CI: 0.772,0.924; p < 0.001). Besides, we found that high serum levels of hs-cTnI were significantly correlated with disease activity. Moreover, patients with higher serum levels of hs-cTnI tended to suffer from poor prognosis. CONCLUSIONS: Serum hs-cTnI testing may play a role in screening for cardiac involvement in IIM patients. Abnormal levels of serum hs-cTnI were associated with increased disease activity and poor prognosis.

The use of high-sensitivity cardiac troponin I in assessing cardiac involvement and Disease prognosis in idiopathic inflammatory myopathy

Abstract Objectives Cardiac involvement is one of the most serious complications of idiopathic inflammatory myopathy (IIM) that indicates poor prognosis. However, there is a lack of effective biomarkers for the identification of cardiac involvement and the prediction of prognosis in IIM. Here, we aimed to explore the value of different cardiac biomarkers in IIM patients. Methods A total of 142 IIM patients in the Department of Rheumatology and Immunology, Ruijin Hospital from July 2019 to October 2022 were included in this study. The clinical characteristics, laboratory tests, treatments and prognosis were recorded. The disease activity was assessed according to the core set measures. The correlations of the serum cardiac biomarkers levels with disease activity were analyzed by the Spearman correlation test. Risk factors for cardiac involvement were evaluated by multivariate logistic regression analysis. Results Higher high-sensitivity cardiac troponin I (hs-cTnI) levels were associated with cardiac involvement (n = 41) in IIM patients [adjusted OR 7.810 (95% CI: 1.962-31.097); p = 0.004], independent of other serum cardiac biomarkers. The abnormal hs-cTnI had the highest AUC for distinguishing of cardiac involvement in IIM patients (AUC = 0.848, 95% CI: 0.772,0.924; p < 0.001). Besides, we found that high serum levels of hs-cTnI were significantly correlated with disease activity. Moreover, patients with higher serum levels of hs-cTnI tended to suffer from poor prognosis. Conclusions Serum hs-cTnI testing may play a role in screening for cardiac involvement in IIM patients. Abnormal levels of serum hs-cTnI were associated with increased disease activity and poor prognosis. Key Points Among all the cardiac biomarkers, the serum levels of hs-cTnI were independently associated with cardiac involvement in IIM patients. The serum levels of hs-cTnI were significantly correlated with disease activity in IIM patients. The abnormal hs-cTnI levels were correlated with poor prognosis in IIM patients.