Differential expression of FGF receptors and of myogenic regulatory factors in primary cultures of satellite cells originating from fast (EDL) and slow (Soleus) twitch rat muscles.

In the rat, the fast and slow twitch muscles respectively Extensor digitorum longus (EDL) and Soleus present differential characteristics during regeneration. This suggests that their satellite cells responsible for muscle growth and repair represent distinct cellular populations. We have previously shown that satellite cells dissociated from Soleus and grown in vitro proliferate more readily than those isolated from EDL muscle.

Differential myogenicity of satellite cells isolated from extensor digitorum longus (EDL) and soleus rat muscles revealed in vitro.

Following muscle damage, fast- and slow-contracting fibers regenerate, owing to the activation of their satellite cells. In rats, crush-induced regeneration of extensor digitorum longus (EDL, a fast muscle) and soleus (a slow muscle) present different characteristics, suggesting that intrinsic differences exist among their satellite cells. An in vitro comparative study of the proliferation and differentiation capacities of satellite cells isolated from these muscles is presented there.

Growth factors in skeletal muscle regeneration.

Adult skeletal muscles are able to regenerate after injury. This process is due to the activation of quiescent muscle precursor cells, also called satellite cells, which proliferate and differentiate to form new myotubes. In this regeneration process, several growth factors which come from the muscle and/or from the motor nerve and inflammatory cells have been shown to play key roles.

Production and purification of active FGF2 via recombinant fusion protein.

Basic fibroblast growth factor (FGF2) is involved in both cell proliferation and differentiation processes. Heparin may interfere in the stability and biological activities of FGFs. However, it is difficult to obtain FGF preparation without traces of heparin since heparin affinity chromatographies are routinely used to prepare this growth factor.

FGFs and their receptors, in vitro and in vivo studies: new FGF receptor in the brain, FGF-1 in muscle, and the use of functional analogues of low-affinity heparin-binding growth factor receptors in tissue repair.

Several heparin-binding growth factors (HBGFs) are thought to play a key role in the natural processes of tissue homeostasis, regeneration or repair. The HBGFs are active upon release from neighbouring inflammatory or circulating cells, as well as upon release from heparan sulfate proteoglycosaminoglycans that are associated with the extracellular matrix (ECM). To better understand the physiological role of these HBGFs, we have focused our effort on studying a subset of HBGFs, namely FGF-1 and FGF-2 and their receptors.