Immune mediated necrotising myopathies (IMNM) may be associated with anti-SRP or anti-HMGCR antibodies and the titre of these antibodies is correlated with the disease activity. In this study, the investigators have examined the hypothesis that anti-SRP and anti-HMGCR antibodies may be involved in muscle damage.
Muscle biopsies of patients were analysed for atrophy and regeneration, by measuring the fibre size and by performing immunostaining of neonatal myosin heavy chain. To further understand the role of the antibodies in the pathology, the investigators co-cultured muscle cells with these antibodies. Atrophy and regeneration were evaluated based on the myotube surface area as well as gene and cytokine profiles.
These experiments have shown that the molecular mechanisms of atrophy and regeneration are altered and contribute to the loss of muscle function occurring in MNMI. This emphasizes the potential interest of targeted therapies addressing these mechanisms.
