**6. Conclusion**

The muscular stem cell niche is a remarkable structure that enables satellite cells and other non-satellite myogenic cells to repair and regenerate skeletal muscles when needed. As previously stated, the niche componence is highly variable, depending not only on the age of the body, but also on its well-being since a multitude of degenerative muscle disorders can alter the stem cell environment, leading to a decrease in the regenerative abilities of satellite cells. One of the elements of the niche that was proved to change during aging is the basal lamina, a key structure that apparently tends to interpose between the myofibers and satellite cells in older muscles, thus altering their communication, a fact that is believed to be associated to the latter's decrease in number. Furthermore, it was observed that in aged skeletal muscles, myofibers were decreased in mass, in contrast to the number of fibroblasts and adipocytes, which tended to increase. Satellite cells displayed diminished myogenic abilities and an accelerated apoptosis, probably due to lower expression levels of Pax7. Similar changes were described in degenerative muscle disorders, one of the most studied and severe being Duchenne muscular dystrophy. The chronic inflammation that appears in these diseases is believed to thicken the basal lamina and overflow the satellite cells with signaling molecules, impairing their capacity to restore muscle fibers. Other chronic disorders like diabetes mellitus and cachexia were also associated with niche alterations. Research in the field of regenerative medicine promises to innovate the therapies in these pathologies; however, there is a long way ahead and additional studies are needed.
