Differential satellite cell density of type I and II fibres with lifelong endurance running in old men

TY - JOUR

T1 - Differential satellite cell density of type I and II fibres with lifelong endurance running in old men

AU - Mackey, Abigail

AU - Karlsen, A

AU - Couppé, C

AU - Mikkelsen, U R

AU - Nielsen, R H

AU - Magnusson, S P

AU - Kjaer, M

N1 - © 2013 Scandinavian Physiological Society. Published by John Wiley & Sons Ltd.

PY - 2014/3

Y1 - 2014/3

N2 - AIM: To investigate the influence of lifelong endurance running on the satellite cell pool of type I and type II fibres in healthy human skeletal muscle.METHODS: Muscle biopsies were collected from 15 healthy old trained men (O-Tr) who had been running 43 ± 16 (mean ± SD) kilometres a week for 28 ± 9 years. Twelve age-matched untrained men (O-Un) and a group of young trained and young untrained men were recruited for comparison. Frozen sections were immunohistochemically stained for Pax7, type I myosin and laminin, from which fibre area, the number of satellite cells, and the relationship between these variables were determined.RESULTS: In O-Un and O-Tr, type II fibres were smaller and contained fewer satellite cells than type I fibres. However, when expressed relative to fibre area, the difference in satellite cell content between fibre types was eliminated in O-Tr, but not O-Un. A strong positive relationship between fibre size and satellite cell content was detected in trained individuals. In line with a history of myofibre repair, a greater number of fibres with centrally located myonuclei were detected in O-Tr.CONCLUSION: Lifelong endurance training (i) does not deplete the satellite cell pool and (ii) is associated with a similar density of satellite cells in type I and II fibres despite a failure to preserve the equal fibre type distribution of satellite cells observed in young individuals. Taken together, these data reveal a differential regulation of satellite cell content between fibre types, in young and old healthy men with dramatically different training histories.

AB - AIM: To investigate the influence of lifelong endurance running on the satellite cell pool of type I and type II fibres in healthy human skeletal muscle.METHODS: Muscle biopsies were collected from 15 healthy old trained men (O-Tr) who had been running 43 ± 16 (mean ± SD) kilometres a week for 28 ± 9 years. Twelve age-matched untrained men (O-Un) and a group of young trained and young untrained men were recruited for comparison. Frozen sections were immunohistochemically stained for Pax7, type I myosin and laminin, from which fibre area, the number of satellite cells, and the relationship between these variables were determined.RESULTS: In O-Un and O-Tr, type II fibres were smaller and contained fewer satellite cells than type I fibres. However, when expressed relative to fibre area, the difference in satellite cell content between fibre types was eliminated in O-Tr, but not O-Un. A strong positive relationship between fibre size and satellite cell content was detected in trained individuals. In line with a history of myofibre repair, a greater number of fibres with centrally located myonuclei were detected in O-Tr.CONCLUSION: Lifelong endurance training (i) does not deplete the satellite cell pool and (ii) is associated with a similar density of satellite cells in type I and II fibres despite a failure to preserve the equal fibre type distribution of satellite cells observed in young individuals. Taken together, these data reveal a differential regulation of satellite cell content between fibre types, in young and old healthy men with dramatically different training histories.

U2 - 10.1111/apha.12195

DO - 10.1111/apha.12195

M3 - Journal article

C2 - 24219628

SN - 1748-1708

VL - 210

SP - 612

EP - 627

JO - Acta Physiologica

JF - Acta Physiologica

IS - 3

ER -