Marie-Agnès Metgès, MD, is a lecturer and hospital practitioner at the University Hospital of Brest. At the hospital, she is responsible for a lung function testing unit, which caters mainly to children. Moreover, her basic research focuses on the adaptation of the neuromuscular system to environmental constraints. She currently works at the Institute of Myology in Yves Fromes group in the laboratory of experimental physiology. What is your research thematic at the Institute?
We are seeking to understand the mechanisms of the nervous system adaptation to the progressive muscular weakness and impairment: what is the new equilibrium between the muscle and its nervous control? In this context, we are studying the limb girdle muscular dystrophy observed in the CHF147 hamster, a spontaneous animal model of delta-sarcoglycan deficiency. This animal model presents a myopathy preferentially affecting the proximal skeletal muscles and a cardiomyopathy ultimately lethal to the animal. Precisely, what are your objectives?
Three aims are pursued in this study. The first aim is the comparison of results - qualitative and quantitative - obtained in healthy and myopathic animals. Furthermore, we would like to describe the natural history of the disease and establish relevant follow-up criteria. Finally, we would like to assess the impact of possible changes induced by systemic gene therapy treatment. To meet these objectives, we will carry out functional electrophysiological explorations in healthy and sick animals, particularly by recording the electromyographic activity of proximal and distal muscles during walking (EMG) and by measuring the muscle response during stimulation tests. What is the experimental procedure for this type of study?
At the moment, we need to improve the intramuscular recording device, which allows to capture the electromyographic activity in dynamic conditions, i.e. when the animal moves and during stimulation tests. The recording is made during an imposed walking activity on a treadmill. A standardized treadmill walking session is imposed to animals previously selected according to their ability to run on the treadmill. The walking EMG allows us to analyse the overall nervous activity and the stimulation tests allow recording muscle action potentials during maximal contraction. We are currently defining the most relevant criteria for comparison between myopathic and control animals. When will you obtain the first results?
We have already begun to collect data, but in 6 months, we will have stronger results concerning the comparison of myopathic / healthy animals and some hamsters will have been treated.
Interview by Anne Berthomier, translation by Racquel N. Cooper