title: Embracing change: striated-for-smooth muscle replacement in esophagus development.
abstract: The esophagus functions to transport food from the oropharyngeal region to the stomach via waves of peristalsis and transient relaxation of the lower esophageal sphincter. The gastrointestinal tract, including the esophagus, is ensheathed by the muscularis externa (ME). However, while the ME of the gastrointestinal tract distal to the esophagus is exclusively smooth muscle, the esophageal ME of many vertebrate species comprises a variable amount of striated muscle. The esophageal ME is initially composed only of smooth muscle, but its developmental maturation involves proximal-to-distal replacement of smooth muscle with striated muscle. This fascinating phenomenon raises two important questions: what is the developmental origin of the striated muscle precursor cells, and what are the cellular and morphogenetic mechanisms underlying the process? Studies addressing these questions have provided controversial answers. In this review, we discuss the development of ideas in this area and recent work that has shed light on these issues. A working model has emerged that should permit deeper understanding of the role of ME development and maturation in esophageal disorders and in the functional and evolutionary underpinnings of the variable degree of esophageal striated myogenesis in vertebrate species.
authors: Department of Developmental and Regenerative Biology, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1020, New York, NY 10029 USA.
authors: Robert S
authors: RS
authors: Krauss
authors: Department of Developmental and Regenerative Biology, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1020, New York, NY 10029 USA.
authors: Daisuke
authors: D
authors: Chihara
authors: Department of Developmental and Regenerative Biology, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1020, New York, NY 10029 USA ; Present address: Department of Genetics and Development, Columbia University, 701 West 168th Street, HHSC 1602, New York, NY 10032 USA.
authors: Anthony I
authors: AI
authors: Romer
mesh_terms: D000818:Animals; D004947:Esophagus / Q000196:embryology / Q000254:growth & development* / Q000378:metabolism; D006801:Humans; D008954:Models, Biological; D024510:Muscle Development; D018485:Muscle Fibers, Skeletal / Q000502:physiology; D009130:Muscle, Smooth / Q000196:embryology / Q000254:growth & development* / Q000378:metabolism; D054792:Muscle, Striated / Q000196:embryology / Q000254:growth & development* / Q000378:metabolism; D032446:Myoblasts / Q000502:physiology; D032389:Myocytes, Smooth Muscle / Q000502:physiology