I was reviewing the ISSA text and ran across the fiber fusion theory. You know where satelitte cells fuse with muscle fibers in order to repair or strengthen muscle cells that have been damaged. (Type IIc) I am wandering what kind of supplementation and exercise practices are necessary for this possible occurance to happen?
Satellite cells are activated by the paracrine/autocrine IGF-1 system. This system is stimulated heavy loading (i.e. intense resistance training). The muscle fibers (i.e. the damaged ones) release the IGF-1 (note: this is not plasma IGF-1 that is stimulated by GH) and this IGF-1 stimulates proliferation and differentiation of Satellite cells. The satellite cells then migrate to the damaged fibers–either the same fiber that produced the Satellite cells (which are found beneath the basal lamina) or to adjacent damaged fibers. The Satellite cells either fuse with the damaged fibers to donate a new nucleus (read below for the importance of the nucleus addition) or with another Satellite cell.
There is evidence in the literature that a certain myoplasmic domain exists. That is, in order for a muscle to hypertrophy, the ratio of myonuclei to sarcoplasma must remain constant.
Interesting stuff. Anyone have any answers?