Brain activity and perceived exertion during cycling exercise: an fMRI study.

Background/aim: Currently, the equipment and techniques available to assess brain function during dynamic exercise are limited, which has restricted our knowledge of how the brain regulates exercise. This study assessed the brain areas activated during cycling by making use of a novel cycle ergometer, constructed to measure functional MRI (fMRI) brain images during dynamic exercise. Furthermore, we compared brain activation at different levels of ratings of perceived exertion (RPE) generated during the exercise.

TGF-β isoforms inhibit IGF-1-induced migration and regulate terminal differentiation in a cell-specific manner.

Following muscle injury, the damaged tissue and influx of inflammatory cells stimulate the secretion of growth factors and cytokines to initiate repair processes. This release of chemotactic signaling factors activates resident precursor cells and stimulates their mobilization and migration to the site of injury where terminal differentiation can occur. The three transforming growth factor-β (TGF-β) isoforms, and insulin-like growth factor-1 (IGF-1) are among the known regulatory factors released following muscle damage.

Potential myogenic stem cell populations: sources, plasticity, and application for cardiac repair.

The ability of unspecialized stem cells to differentiate into mature, specialized cell types has made them attractive as potential agents for enhanced tissue repair and regenerative medicine. This is especially true of diseases and disorders for which no or only partially effective treatments are currently available. Recently, increased focus has been placed on the regenerative potential of satellite cells (myogenic precursor cells found in the adult skeletal muscle) in various muscular disorders, such as dystrophy and myocardial injury following ischemia.

TGF-beta's delay skeletal muscle progenitor cell differentiation in an isoform-independent manner.

Satellite cells are a quiescent heterogeneous population of mononuclear stem and progenitor cells which, once activated, differentiate into myotubes and facilitate skeletal muscle repair or growth. The Transforming Growth Factor-beta (TGF-beta) superfamily members are elevated post-injury and their importance in the regulation of myogenesis and wound healing has been demonstrated both in vitro and in vivo. Most studies suggest a negative role for TGF-beta on satellite cell differentiation.