MDA5: the almighty for Myocardium

Cardiac involvement in a case of juvenile dermatomyositis with positive anti-melanoma differentiation associated protein 5 antibody

Juvenile dermatomyositis (JDM) is an autoimmune disease characterized by muscle weakness and specific skin lesions, as well as non-muscular involvement such as interstitial lung disease (ILD), cardiac involvement and arthritis. Anti-melanoma differentiation-associated protein 5 (anti-MDA5)-positive JDM patients are typically characterized by the presence of skin ulcers and rapidly progressing ILD (RP-ILD). Although cardiac involvement is not an expected involvement in anti-MDA5-positive JDM cases, it is significant because it can be fatal. In this report, an anti-MDA5 myositis-specific autoantibody-positive JDM case referred with the diagnosis of psoriatic arthritis in whom cardiomyopathy and arrhythmia were detected in follow-up is presented. Since cardiac involvement is associated with mortality, it would be useful to follow up anti-MDA5 positive patients for cardiac involvement in addition to lung involvement. Tofacitinib is a promising treatment option in treatment-resistant JDM.

The role of sex differences in autophagy in the heart during coxsackievirus B3-induced myocarditis

Under normal conditions, autophagy maintains cardiomyocyte health and integrity through turnover of organelles. During stress, oxygen and nutrient deprivation, or microbial infection, autophagy prolongs cardiomyocyte survival. Sex differences in induction of cell death may to some extent explain the disparity between the sexes in many human diseases. However, sex differences in gene expression, which regulate cell death and autophagy, were so far not taken in consideration to explain the sex bias of viral myocarditis. Coxsackievirus B3 (CVB3)-induced myocarditis is a sex-biased disease, with females being substantially less susceptible than males and sex hormones largely determine this bias. CVB3 was shown to induce and subvert the autophagosome for its optimal viral RNA replication. Gene expression analysis on mouse and human, healthy and CVB3-infected, cardiac samples of both sexes, suggests sex differences in autophagy-related gene expression. This review discusses the aspects of sex bias in autophagy induction in cardiomyocytes.