An international research team with the participation of the University Medical Center Göttingen (UMG) has developed a mouse model that provides new insights into the development of the rare inclusion body myositis. The scientists were able to show that the chronic inflammation in this muscle disease is related to impaired cellular “garbage disposal” (autophagy) and that both processes reinforce each other.

Inclusion body myositis is a chronically progressive disease that mainly affects people aged 45 and over. It leads to muscle weakness and breakdown, especially in the thighs and deep finger flexors. Proteins are deposited in the muscle fibers, causing changes in the mitochondria – the energy producers of the cells. Unlike other muscle inflammations, the disease hardly responds to conventional anti-inflammatory drugs.

In the study, which was published in the journal “Brain”, the researchers from Göttingen, Heidelberg, Aachen, Freiburg, Munich and Switzerland developed genetically modified mice that mimic both the inflammatory processes and the impaired cell cleansing of the human disease. For the first time, the model depicts all the essential characteristics of inclusion body myositis and thus enables targeted investigations of the disease mechanisms.

The results suggest that the persistent inflammation and impaired autophagy form a vicious cycle: the inflammation hinders the garbage disposal in the cells, and the accumulation of cellular waste in turn increases the inflammation. This could explain why classic immunosuppressants usually have an inadequate effect in this disease – even with successful suppression of inflammation, muscle weakness and cell changes remain.

Co-author Dr. Jana Zschüntzsch from the Department of Neurology at the UMG emphasized that the new mouse model is a decisive step forward, as no suitable animal model was previously available to test new therapies. Prof. Dr. Jens Schmidt, last author of the study, compared the situation to an untidy household in which dust is constantly stirred up.

The researchers plan to test various innovative therapeutic approaches in the model in the coming years. The study was published online in “Brain” on August 25, 2025 (Bremer et al., DOI: 10.1093/brain/awaf260).

Editor: X-Press Journalistenbüro GbR

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