New treatments are urgently needed to slow disease progression in patients with DMD
Currently, glucocorticoids are the only available medical treatment that can slow the decline in muscle strength and function, irrespective of the disease-causing mutation. 3,5,13,17,18 However, the effect is only partial and clinical use is limited by well-known side effects caused by steroids. 3,5,13,17,18 A recent study showed that up to 42% of DMD patients aged 10 years and older had either never used steroids or have discontinued their use. 5 Loss of respiratory function with increasing age continues to be a major cause of morbidity and mortality in patients with DMD, and new treatments to support respiratory function are needed urgently. 2,6,13,17
Seen under a microscope, muscles are made up of bundles of individual muscle fibers. Under greater magnification, each fiber is seen to have an outer membrane. Dystrophin is believed to be responsible for maintaining the structure of the muscle fiber membrane. Without it, the membrane tends to fall apart and become "leaky." One of the substances that leaks out from inside the muscle fibers is creatine kinase (KREE-a-tin KI-naze), which is needed for the chemical reactions that produce energy for muscle contraction.
Curiously, in the mdx mouse model of Duchenne muscular dystrophy, the lack of dystrophin is associated with increased calcium levels and skeletal muscle myonecrosis. The intrinsic laryngeal muscles (ILMs) are protected and do not undergo myonecrosis.  ILMs have a calcium regulation system profile suggestive of a better ability to handle calcium changes in comparison to other muscles, and this may provide a mechanistic insight for their unique pathophysiological properties.  The ILM may facilitate the development of novel strategies for the prevention and treatment of muscle wasting in a variety of clinical scenarios.