Neil A Kelly1,2, Kelley G Hammond2,3, Michael J Stec1,2, C Scott Bickel2,3, Samuel T Windham2,4, S Craig Tuggle1,2, Marcas M Bamman1,2,5. 1. Departments of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama, USA. 2. UAB Center for Exercise Medicine, 1313 13th Street South, OSB Room 300, University of Alabama at Birmingham, Birmingham, Alabama, 35205-5327, USA. 3. Department of Physical Therapy, University of Alabama at Birmingham, Birmingham, Alabama, USA. 4. Department of Surgery, University of Alabama at Birmingham, Birmingham, Alabama, USA. 5. Geriatric Research, Education, and Clinical Center, VA Medical Center, Birmingham, Alabama, USA.
Abstract
INTRODUCTION: Myofiber type grouping is a histological hallmark of age-related motor unit remodeling. Despite the accepted concept that denervation-reinnervation events lead to myofiber type grouping, the completeness of those conversions remains unknown. METHODS: Type I myofiber grouping was assessed in vastus lateralis biopsies from Young (26 ± 4 years; n = 27) and Older (66 ± 4 years; n = 91) adults. Grouped and ungrouped type I myofibers were evaluated for phenotypic differences. RESULTS: Higher type I grouping in Older versus Young was driven by more myofibers per group (i.e., larger group size) (P < 0.05). In Older only, grouped type I myofibers displayed larger cross-sectional area, more myonuclei, lower capillary supply, and more sarco(endo)plasmic reticulum calcium ATPase I (SERCA I) expression (P < 0.05) than ungrouped type I myofibers. DISCUSSION: Grouped type I myofibers retain type II characteristics suggesting that conversion during denervation-reinnervation events is either progressive or incomplete. Muscle Nerve 57: E52-E59, 2018.
INTRODUCTION: Myofiber type grouping is a histological hallmark of age-related motor unit remodeling. Despite the accepted concept that denervation-reinnervation events lead to myofiber type grouping, the completeness of those conversions remains unknown. METHODS: Type I myofiber grouping was assessed in vastus lateralis biopsies from Young (26 ± 4 years; n = 27) and Older (66 ± 4 years; n = 91) adults. Grouped and ungrouped type I myofibers were evaluated for phenotypic differences. RESULTS: Higher type I grouping in Older versus Young was driven by more myofibers per group (i.e., larger group size) (P < 0.05). In Older only, grouped type I myofibers displayed larger cross-sectional area, more myonuclei, lower capillary supply, and more sarco(endo)plasmic reticulum calcium ATPase I (SERCA I) expression (P < 0.05) than ungrouped type I myofibers. DISCUSSION: Grouped type I myofibers retain type II characteristics suggesting that conversion during denervation-reinnervation events is either progressive or incomplete. Muscle Nerve 57: E52-E59, 2018.
Authors: Michael J Stec; Neil A Kelly; Gina M Many; Samuel T Windham; S Craig Tuggle; Marcas M Bamman Journal: Am J Physiol Endocrinol Metab Date: 2016-02-09 Impact factor: 4.310
Authors: Neil A Kelly; Matthew P Ford; David G Standaert; Ray L Watts; C Scott Bickel; Douglas R Moellering; S Craig Tuggle; Jeri Y Williams; Laura Lieb; Samuel T Windham; Marcas M Bamman Journal: J Appl Physiol (1985) Date: 2014-01-09
Authors: Edward K Merritt; Michael J Stec; Anna Thalacker-Mercer; Samuel T Windham; James M Cross; David P Shelley; S Craig Tuggle; David J Kosek; Jeong-Su Kim; Marcas M Bamman Journal: J Appl Physiol (1985) Date: 2013-05-16
Authors: Sudhakar Aare; Sally Spendiff; Madhusudanarao Vuda; Daren Elkrief; Anna Perez; Qinghua Wu; Dominique Mayaki; Sabah N A Hussain; Stefan Hettwer; Russell T Hepple Journal: Skelet Muscle Date: 2016-09-01 Impact factor: 4.912
Authors: Kaleen M Lavin; Brandon M Roberts; Christopher S Fry; Tatiana Moro; Blake B Rasmussen; Marcas M Bamman Journal: Physiology (Bethesda) Date: 2019-03-01
Authors: Neil A Kelly; Kelley G Hammond; C Scott Bickel; Samuel T Windham; S Craig Tuggle; Marcas M Bamman Journal: J Appl Physiol (1985) Date: 2017-12-21
Authors: Kaleen M Lavin; Paul M Coen; Liliana C Baptista; Margaret B Bell; Devin Drummer; Sara A Harper; Manoel E Lixandrão; Jeremy S McAdam; Samia M O'Bryan; Sofhia Ramos; Lisa M Roberts; Rick B Vega; Bret H Goodpaster; Marcas M Bamman; Thomas W Buford Journal: Compr Physiol Date: 2022-03-09 Impact factor: 8.915
Authors: Cory M Dungan; Bailey D Peck; R Grace Walton; Zhengyan Huang; Marcas M Bamman; Philip A Kern; Charlotte A Peterson Journal: FASEB J Date: 2020-04-04 Impact factor: 5.191
Authors: Brandon M Roberts; Kaleen M Lavin; Gina M Many; Anna Thalacker-Mercer; Edward K Merritt; C Scott Bickel; David L Mayhew; S Craig Tuggle; James M Cross; David J Kosek; John K Petrella; Cynthia J Brown; Gary R Hunter; Samuel T Windham; Richard M Allman; Marcas M Bamman Journal: Exp Gerontol Date: 2018-02-24 Impact factor: 4.032
Authors: Kaleen M Lavin; Stuart C Sealfon; Merry-Lynn N McDonald; Brandon M Roberts; Katarzyna Wilk; Venugopalan D Nair; Yongchao Ge; Preeti Lakshman Kumar; Samuel T Windham; Marcas M Bamman Journal: J Appl Physiol (1985) Date: 2019-12-12
Authors: Mary Rieger; Pamela Duran; Mark Cook; Simon Schenk; Manali Shah; Marni Jacobs; Karen Christman; Deborah M Kado; Marianna Alperin Journal: Ann Biomed Eng Date: 2021-03-08 Impact factor: 3.934