Skeletal muscles are one of the largest cells in the body (2–3 cm long). They are formed by thousands of nuclei that share the same cytoplasm. These large cells are highly irrigated with blood vessels to provide the oxygen. Oxygen is used to burn glucose and produce energy for muscle contraction and movement. Glucose can be metabolized in different pathways (glycolysis or oxidation) depending on fiber type. Glycolytic fibers can act fast, but are exhausted quickly, while oxidative fibers can maintain longer periods of contractions.
Fiber types are affected differently in aging and muscle disorders. Understanding how the differences between fiber types and how these are defined during development can potentially contribute to the development of therapies.
We are finalizing the study on healthy muscle. We have found that contrary to believe muscles are heterogenous organs with different regions. We are now setting up the study to include disease muscle samples from Duchene Muscular Dystrophy (DMD). We hope to characterize the differences between healthy and disease muscle to deepen our understanding of this disease.
3D reconstruction of a 350 mm muscle section. Fragments of longitudinal skeletal muscle fibers are delimited by laminin (cyan) and contain multiple nuclei (yellow). Haemoglobin (magenta) marks the blood vessels surrounding the fibers.
Clara Martinez Mir, Niels Geijsen lab, LUMC