Charge, Sophie B. P., and Michael A. Rudnicki. Cellular and Molecular Regulation of Muscle Regeneration. Physiol Rev 84: 209–238, 2004; 10.1152/physrev.00019.2003.—Under normal circumstances, mamma...

Cellular and Molecular Regulation of Muscle Regeneration

The changing faces of glutathione, a cellular protagonist

After injury, muscle healing occurs through different phases, including (1) degeneration and inflammation, (2) muscle regeneration, and (3) development of fibrosis.

The severity and type of muscle injury influence the healing process.

Enhancement of muscle regeneration and prevention of muscle fibrosis can improve muscle healing.

Growth factors, including basic fibroblast growth factor (bFGF), insulin-like growth factor-1 (IGF-1), and nerve growth factor (NGF), can improve muscle regeneration, but the post-injury healing process remains incomplete.

The use of anti-fibrosis agents that antagonize the effect of transforming growth factor-β1 (TGF-β1) can prevent fibrosis and improve muscle healing, resulting in nearly complete recovery.

Optimal muscle recovery may require the use of novel technologies, such as gene therapy and tissue engineering, to achieve both high levels and long-term persistence of these growth factors and cytokines within the injured muscle.

Muscle injury presents a challenging problem in traumatology, as injured muscles heal very slowly and often with incomplete functional recovery. It has been observed that injured muscles can initiate regeneration promptly, but the healing process is often inefficient and hindered by the formation of scar tissue, which may contribute to the tendency for muscle injury to recur. The enhancement of muscle regeneration and the prevention of muscle fibrosis through the use of biological approaches are being investigated in an effort to improve muscle healing after injury. In this Current Concepts Review, we will outline the structure and histological organization of skeletal muscle and describe the basic physiology of skeletal muscle contraction. We will subsequently summarize the biological and pathological processes that occur in skeletal muscle after injury (i.e., degeneration, inflammation, regeneration, and fibrosis) and present the clinical treatments currently available for injured skeletal muscle. Finally, we will discuss current trends in research, which include the improvement of regeneration and the inhibition of fibrosis in injured skeletal …

Muscle injuries and repair: current trends in research.

Synthesis and in vitro antitumor evaluation of some indeno[1,2-c]pyrazol(in)es substituted with sulfonamide, sulfonylurea(-thiourea) pharmacophores, and some derived thiazole ring systems.

The insulin-like growth factors are major regulators of growth and development in mammals and their presence in lower vertebrates suggests that they played a similarly fundamental role throughout vertebrate evolution. While originally perceived simply as mediators of growth hormone, on-going research in mammals has revealed several hierarchical layers of complexity in the regulation of ligand bioavailability and signal transduction. Our understanding of the biological role and mechanisms of action of these important growth factors in mammals patently requires further elucidation of the IGF hormone system in the simple model systems that can be found the in lower vertebrates and protochordates. This review contrasts our knowledge of the IGF hormone system in mammalian and nonmammalian models through comparison of tissue and developmental distributions and gene structures of IGF system components in different taxa. We also discuss the evolutionary origins of the system components and their possible evolutionary pathways.

The phylogeny of the insulin-like growth factors.

The Influence of Growth Factors on Turkey Embryonic Myoblasts and Satellite Cells in Vitro

Variation in response to growth factor stimuli in satellite cell populations.

Satellite cells were isolated from the skeletal muscles of turkey varieties which grow at different rates to explore cellular mechanisms that may influence the rate of muscular growth. Satellite cells from the fast growing variety (Nicholas) were more responsive to insulin-like growth factors (IGFs) and insulin, and less responsive to fibroblast growth factor than were cells derived from the slow growing (Merriam's) turkey. IGF receptor affinities were similar between the Nicholas and Merriam's turkey satellite cells. The results suggest that differences in the responses of satellite cells to growth factors may influence rates of skeletal muscle accretion and whole body growth.

The response to growth factors of cultured satellite cells derived from turkeys having different growth rates.

Satellite cells were isolated from the pectoralis major (PM) and biceps femoris (BF) muscles of 5-week-old broiler chickens to compare growth and differentiation characteristics in vitro. BF cells proliferated at greater rates in the growth medium and were more responsive to the mitogenic effects of chicken serum than PM cells at all levels tested (p < or = 0.05). When low serum-containing medium was administered, the levels of creatine kinase, a marker of differentiation, increased at greater rates in PM cultures than in BF cultures (p < or = 0.05). Administration of increasing levels of fibroblast growth factor in serum-free medium resulted in similar responsiveness of the two lines to this mitogen. No differences were detected in rates of protein synthesis or degradation in myotube cultures from the two muscle sources. The results suggest that satellite cells derived from PM and BF muscles of the chicken have different responsiveness to serum mitogens.

Kysa K. Gilkerson

Papers

The Influence of Growth Factors on Turkey Embryonic Myoblasts and Satellite Cells in Vitro

Variation in response to growth factor stimuli in satellite cell populations.

The response to growth factors of cultured satellite cells derived from turkeys having different growth rates.

In vitro characteristics of myogenic satellite cells derived from the pectoralis major and biceps femoris muscles of the chicken.

The effect of hepatocyte growth factor on turkey satellite cell proliferation and differentiation