Muscle disorders are caused by disruption of normal innervation, degeneration and replacement of muscle cells, injury, lack of use or disease.
Muscular atrophy refers to a decrease in size of muscles. Individual muscle fibers decrease in size, and there is a progressive loss of myofibrils.
Disuse atrophy is a muscular atrophy that results from lack of muscle use. Bedridden people, people with limbs in casts, or those who are inactive for other reasons experience disuse atrophy in the muscles that are not used. Disuse atrophy is temporary if a muscle is exercised after it is taken out of a cast. However, extreme disuse of a muscle results in muscular atrophy in which there is a permanent loss of skeletal muscle fibers and the replacement of those fibers by connective tissue. Immobility that occurs in bedridden elderly people can lead to permanent and severe muscular atrophy.
Denervation atrophy results when nerves that supply skeletal muscles are severed. When motor neurons innervating skeletal muscle fibers are severed, the result is flaccid paralysis. If the muscle is reinnervated, muscle function is restored, and atrophy is stopped. However, if skeletal muscle is permanently denervated, it atrophies and exhibits permanent flaccid paralysis. Eventually muscle fibers are replaced by connective tissue, and the condition cannot be reversed.
Transcutaneous stimulators are used to supply electrical stimuli to muscles that have had their nerves temporarily damaged or to muscles that are put in casts for a prolonged period of time. The electrical stimuli keep the muscles functioning and prevent permanent atrophy of the muscles while the nerves resupply the muscles or until the cast is removed.
Muscular dystrophy is one of a group of diseases called myopathies that destroy skeletal muscle tissue. Usually the diseases are inherited and are characterized by degeneration of muscle cells, leading to atrophy and eventual replacement by connect
I'm gonna just assume you were reading quickly. Simp meant it exactly the way he wrote it. As DMD progresses, the muscles show a rapid increase in fibrotic tissue that ceases to function as normal muscle. If I'm not mistaken, there is a known, and measurable increase in this fibrotic tissue as the disease progresses. Any drug that could stop the progression from healthy muscle tissue into fibrotic, useless tissue, would be.............uh.............a GAME CHANGER.
Simp was implying that the MRI information seems to also be showing the Eteplirsen works in that the muscles are NOT becoming more and more fibrotic based on MRI scans. How you missed this pretty simply point is curious.