Understanding Loss of Muscle Mass and Function

Sarcopenia is a loss of muscle mass and function that develops during aging. But sarcopenia is also observed in several other conditions: chronic diseases, cancers, viral infections, renal / respiratory insufficiency, immobility, obesity with low physical activity. This sarcopenia is named secondary sarcopenia to distinguish it from the age-associated primary sarcopenia. During prolonged hospitalizations in intensive care, a significant loss of muscular mass and function is also observed. This acute sarcopenia or Intensive Care Unit-Acquired Weakness (ICU-AW) may persist for several months after discharge from hospital. In addition to the loss of autonomy, the reduction of muscle mass has important metabolic implications, ranging from insulin resistance to modification of myokines production. Sarcopenia greatly increases the morbidity and mortality of patients regardless of its cause. The aim of our project is to identify the molecular mechanisms implicated in sarcopenia from different origin. We will particularly focus our work on the metabolic properties, the proliferation/ differentiation and regeneration capacities of the satellite cells (adult muscle stem cells). These satellite cells will be purified from quadriceps biopsies of human volunteers recruited at CHU Montpellier. These satellite cells will also be used to test the ability of some wild aromatic plants from south of France to improve cell survival and differentiation. This will allow us to identify the molecular mechanisms involved in sarcopenia development and identify potential therapeutic molecules.