Fibrillations in regenerating muscle in dystrophic myopathies.

In the presented study we attempted to demonstrate a correlation between muscle regeneration and fibrillations in electromyography in dystrophic myopathies. Especially in Emery-Dreifuss muscular dystrophy there is much abnormal spontaneous activity, and NCAM (neural cell adhesion molecule)and cytoskeletal protein vimentin expressing myocytes are predominantly seen. Therefore, definitely regenerating fibers are identified apart from only a few remnants of previous necrosis. Moreover, in the other biopsies of dystrophic myopathies there are also scattered and clustered NCAM and vimentin expressing regenerating myofibers. Here, regressive fiber changes, like necrosis, are more prominent. Furthermore, most regenerating fibers show pseudo-cholinesterase activity indicating innervation. Interestingly, motor end-plate changes in regeneration and in disuse atrophy are very similar. They predominantly consist of terminal sprouting and pseudo-cholinesterase spread. However, in disuse atrophy there is no abnormal spontaneous spread in electromyography. Therefore, in regenerating muscle not innervation, but regeneration itself is likely to be the cause of fibrillations. In conclusion, a correlation is evident between regenerating muscle and fibrillations in electromyography.