title: Effects of distraction on muscle length: mechanisms involved in sarcomerogenesis.
abstract: Although a great deal of interest has been given to understanding the mechanisms involved in regulating the radial growth that occurs because of resistance training, much less has been given to studying the longitudinal growth of skeletal muscle that occurs because of passive stretch. The current authors provide a brief overview of key issues relevant to the longitudinal growth of skeletal muscle that occurs during distraction osteogenesis. Specifically, five key issues are addressed: (1) the pattern of sarcomerogenesis during distraction; (2) sarcomerogenesis and altered expression of sarcomeric and nonsarcomeric genes; (3) the satellite cell hypothesis; (4) mitogenic factors; and (5) new approaches for studying the longitudinal growth of skeletal muscle. A discussion is provided that revolves around the concept of a negative feedback loop. One of the most interesting issues to be resolved in muscle biology is the role of satellite cells in regulating the growth of skeletal muscle. Currently, it is not known whether satellite cell activation is a prerequisite for the longitudinal growth of skeletal muscle. Gene chip analyses provide a paradoxical view, showing that distraction osteogenesis results in the upregulation of a gene, GADD45, involved with growth arrest and deoxyribonucleic acid destruction.
authors.affiliation: Medical Sciences I B-152, Department of Orthopaedics, College of Medicine, University of California, Irvine, CA 92627, USA.
authors.forename: Vincent J
authors.initials: VJ
authors.lastname: Caiozzo
authors.forename: Ali
authors.initials: A
authors.lastname: Utkan
authors.forename: Richard
authors.initials: R
authors.lastname: Chou
authors.forename: Afshin
authors.initials: A
authors.lastname: Khalafi
authors.forename: Heena
authors.initials: H
authors.lastname: Chandra
authors.forename: Michael
authors.initials: M
authors.lastname: Baker
authors.forename: Bryan
authors.initials: B
authors.lastname: Rourke
authors.forename: Greg
authors.initials: G
authors.lastname: Adams
authors.forename: Ken
authors.initials: K
authors.lastname: Baldwin
authors.forename: Stuart
authors.initials: S
authors.lastname: Green
mesh_terms: D000818:Animals; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000502:physiology; D023421:Models, Animal; D018485:Muscle Fibers, Skeletal / Q000502:physiology; D018482:Muscle, Skeletal / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology*; D020411:Oligonucleotide Array Sequence Analysis; D019857:Osteogenesis, Distraction; D020033:Protein Isoforms; D012518:Sarcomeres / Q000502:physiology*; D032496:Satellite Cells, Skeletal Muscle / Q000502:physiology
chemical_list: D020033:Protein Isoforms; D007334:Insulin-Like Growth Factor I