Characteristics of cardiac involvement in immune-mediated necrotizing myopathy

Abstract

ObjectiveTo investigate the characteristics of cardiac involvement due to Immune-mediated Necrotizing Myopathy (IMNM).MethodsPatients diagnosed with Immune-mediated Necrotizing Myopathy (IMNM) who attended the Department of Neurology and the Department of Rheumatology and Immunology at the First Medical Center of the PLA General Hospital between February 2011 and June 2022 were collected. Clinicopathological diagnosis of IMNM was performed according to the criteria established by the European Neuromuscular Center (ENMC). All patients underwent muscle biopsy and Myositis-specific antibodies (MSAs) testing. Information included age, gender, disease duration, intramuscular and extramuscular manifestations, laboratory findings (including creatine kinase, lactate dehydrogenase levels, troponin T, myoglobin and atrial natriuretic peptide), electromyography, skeletal muscle pathology and immunohistochemical staining.ResultsA total of 57 patients were included in this study. Of the serological tests, 56.1% (32/57) were positive for SRP, 21.1% (12/57) were positive for HMGCR and 22.8% (13/57) were seronegative. Thirty patients (52.6%, 30/57) presented with varying degrees of cardiac involvement. We performed ECG in 23 patients and found 6 patients with arrhythmia (26.1%), 12 patients with myocardial ischemia (52.2%), and 7 patients with acute coronary syndrome (ST elevation and non-ST elevation myocardial infarction) (30.4%), and 4 patients with left axis deviation or left ventricular high voltage, suggesting left ventricular hypertrophy (17.4%). Cardiac ultrasound was performed in 14 patients and 3 showed pericardial effusion (21.4%); Decreased left ventricular ejection fraction and atrial enlargement were 2 each; 8 showed a decrease in left ventricular diastolic function (57.1%). In addition, one patient had myocardial edema.ConclusionCardiac involvement is not uncommon in IMNM. However, besides clearly statistically significant differences in the disease course, and in the values of troponin T and myoglobin, our data did not show any statistically significant difference in other features of cardiac involvement between patients with different subtypes of IMNM.

CD163+ macrophage density in perimysial connective tissue associated with prognosis in IMNM

“…20 These results are consistent with previous findings that rates of ILD, dysphagia, cardiac involvement, and severe weakness increase with disease severity. 19,21,22 Despite the impact of current macrophage markers on cardiac involvement is unclear, with persistent inflammation or cytokine storms as a plausible explanation. 23 Tissue-resident macrophages trigger two distinct responses through different metabolic programs: the destruction of infected tissue (inflammatory response, M1 macrophages) or the repair of damaged tissue (regenerative response, M2 macrophages).…”

“…This process contributes to the development of a more severe clinical phenotype 13,18 . Cardiac involvement is a frequent complication of IMNM 19 . Autopsy findings reveal massive macrophage infiltration in both skeletal and cardiac muscle 20 .…”

“… 13 , 18 Cardiac involvement is a frequent complication of IMNM. 19 Autopsy findings reveal massive macrophage infiltration in both skeletal and cardiac muscle. 20 These results are consistent with previous findings that rates of ILD, dysphagia, cardiac involvement, and severe weakness increase with disease severity.…”

“… 20 These results are consistent with previous findings that rates of ILD, dysphagia, cardiac involvement, and severe weakness increase with disease severity. 19 , 21 , 22 Despite the impact of current macrophage markers on cardiac involvement is unclear, with persistent inflammation or cytokine storms as a plausible explanation. 23 …”

Evidence of Cardiac Involvement in a Patient With Necrotizing Autoimmune Myopathy (NAM)

“…Similarly, Suzuki et al identified cardiac involvement in only two of 100 patients with anti-SRP antibody-positive NAM [ 8 ]. A recent study in 2023 found that the prevalence of cardiac involvement in anti-SRP antibody myopathy was 50% (16/32) and included seven patients with acute coronary syndrome [ 9 ]. Takeguchi-Kikuchi et al demonstrated an association between anti-SRP antibody-positive NAM and cardiomyopathy, as proven by positive myocardial biopsy, cardiac MRI, and fluorodeoxyglucose-positron emission tomography [ 10 ].…”