Increase in tendon protein synthesis in response to insulin-like growth factor-I is preserved in elderly men

Rie Harboe Nielsen; Lars Holm; Nikolaj Mølkjær Malmgaard-Clausen; Søren Reitelseder; Katja Maria Heinemeier; Michael Kjaer

doi:10.1152/japplphysiol.01084.2013

Increase in tendon protein synthesis in response to insulin-like growth factor-I is preserved in elderly men

Rie Harboe Nielsen, Lars Holm, Nikolaj Mølkjær Malmgaard-Clausen, Søren Reitelseder, Katja Maria Heinemeier, Michael Kjaer

17 Citationer (Scopus)

Abstract

Insulin-like growth factor-I (IGF-I) is known to be an anabolic factor in tendon, and the systemic levels are reduced with aging. However, it is uncertain how tendon fibroblasts are involved in tendon aging and how aging cells respond to IGF-I. The purpose of this study was to investigate the in vivo IGF-I stimulation of tendon protein synthesis in elderly compared with young men. We injected IGF-I in the patellar tendons of young (n = 11, 20-30 yr of age) and old (n = 11, 66-75 yr of age) men, and the acute fractional synthesis rate (FSR) of tendon protein was measured with the stable isotope technique and compared with the contralateral side (injected with saline as control). We found that tendons injected with IGF-I had significantly higher protein FSR compared with controls (old group: 0.018 ± 0.015 vs. 0.008 ± 0.008, young group: 0.016 ± 0.009 vs. 0.009 ± 0.006%/h, mean ± SE, P < 0.01). This increase in protein synthesis was seen in both young and old men, with no differences between age groups. The old group had markedly lower serum IGF-I levels compared with young (165 ± 17 vs. 281 ± 27 ng/ml, P < 0.01). In conclusion, local IGF-I stimulated tendon protein synthesis in both young and old men, despite lower systemic IGF-I levels in the old group. This could indicate that the changed phenotype in aging tendon is not caused by decreased fibroblast function.

Originalsprog	Engelsk
Tidsskrift	Journal of Applied Physiology
Vol/bind	116
Udgave nummer	1
Sider (fra-til)	42-6
Antal sider	5
ISSN	8750-7587
DOI	https://doi.org/10.1152/japplphysiol.01084.2013
Status	Udgivet - 1 jan. 2014

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10.1152/japplphysiol.01084.2013

Citationsformater

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title = "Increase in tendon protein synthesis in response to insulin-like growth factor-I is preserved in elderly men",

abstract = "Insulin-like growth factor-I (IGF-I) is known to be an anabolic factor in tendon, and the systemic levels are reduced with aging. However, it is uncertain how tendon fibroblasts are involved in tendon aging and how aging cells respond to IGF-I. The purpose of this study was to investigate the in vivo IGF-I stimulation of tendon protein synthesis in elderly compared with young men. We injected IGF-I in the patellar tendons of young (n = 11, 20-30 yr of age) and old (n = 11, 66-75 yr of age) men, and the acute fractional synthesis rate (FSR) of tendon protein was measured with the stable isotope technique and compared with the contralateral side (injected with saline as control). We found that tendons injected with IGF-I had significantly higher protein FSR compared with controls (old group: 0.018 ± 0.015 vs. 0.008 ± 0.008, young group: 0.016 ± 0.009 vs. 0.009 ± 0.006%/h, mean ± SE, P < 0.01). This increase in protein synthesis was seen in both young and old men, with no differences between age groups. The old group had markedly lower serum IGF-I levels compared with young (165 ± 17 vs. 281 ± 27 ng/ml, P < 0.01). In conclusion, local IGF-I stimulated tendon protein synthesis in both young and old men, despite lower systemic IGF-I levels in the old group. This could indicate that the changed phenotype in aging tendon is not caused by decreased fibroblast function.",

keywords = "Adult, Aged, Aging, Fibroblasts, Humans, Insulin-Like Growth Factor I, Male, Patellar Ligament, Protein Biosynthesis, Young Adult",

author = "Nielsen, {Rie Harboe} and Lars Holm and Malmgaard-Clausen, {Nikolaj M{\o}lkj{\ae}r} and S{\o}ren Reitelseder and Heinemeier, {Katja Maria} and Michael Kjaer",

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doi = "10.1152/japplphysiol.01084.2013",

language = "English",

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T1 - Increase in tendon protein synthesis in response to insulin-like growth factor-I is preserved in elderly men

AU - Nielsen, Rie Harboe

AU - Holm, Lars

AU - Malmgaard-Clausen, Nikolaj Mølkjær

AU - Reitelseder, Søren

AU - Heinemeier, Katja Maria

AU - Kjaer, Michael

PY - 2014/1/1

Y1 - 2014/1/1

N2 - Insulin-like growth factor-I (IGF-I) is known to be an anabolic factor in tendon, and the systemic levels are reduced with aging. However, it is uncertain how tendon fibroblasts are involved in tendon aging and how aging cells respond to IGF-I. The purpose of this study was to investigate the in vivo IGF-I stimulation of tendon protein synthesis in elderly compared with young men. We injected IGF-I in the patellar tendons of young (n = 11, 20-30 yr of age) and old (n = 11, 66-75 yr of age) men, and the acute fractional synthesis rate (FSR) of tendon protein was measured with the stable isotope technique and compared with the contralateral side (injected with saline as control). We found that tendons injected with IGF-I had significantly higher protein FSR compared with controls (old group: 0.018 ± 0.015 vs. 0.008 ± 0.008, young group: 0.016 ± 0.009 vs. 0.009 ± 0.006%/h, mean ± SE, P < 0.01). This increase in protein synthesis was seen in both young and old men, with no differences between age groups. The old group had markedly lower serum IGF-I levels compared with young (165 ± 17 vs. 281 ± 27 ng/ml, P < 0.01). In conclusion, local IGF-I stimulated tendon protein synthesis in both young and old men, despite lower systemic IGF-I levels in the old group. This could indicate that the changed phenotype in aging tendon is not caused by decreased fibroblast function.

AB - Insulin-like growth factor-I (IGF-I) is known to be an anabolic factor in tendon, and the systemic levels are reduced with aging. However, it is uncertain how tendon fibroblasts are involved in tendon aging and how aging cells respond to IGF-I. The purpose of this study was to investigate the in vivo IGF-I stimulation of tendon protein synthesis in elderly compared with young men. We injected IGF-I in the patellar tendons of young (n = 11, 20-30 yr of age) and old (n = 11, 66-75 yr of age) men, and the acute fractional synthesis rate (FSR) of tendon protein was measured with the stable isotope technique and compared with the contralateral side (injected with saline as control). We found that tendons injected with IGF-I had significantly higher protein FSR compared with controls (old group: 0.018 ± 0.015 vs. 0.008 ± 0.008, young group: 0.016 ± 0.009 vs. 0.009 ± 0.006%/h, mean ± SE, P < 0.01). This increase in protein synthesis was seen in both young and old men, with no differences between age groups. The old group had markedly lower serum IGF-I levels compared with young (165 ± 17 vs. 281 ± 27 ng/ml, P < 0.01). In conclusion, local IGF-I stimulated tendon protein synthesis in both young and old men, despite lower systemic IGF-I levels in the old group. This could indicate that the changed phenotype in aging tendon is not caused by decreased fibroblast function.

KW - Adult

KW - Aged

KW - Aging

KW - Fibroblasts

KW - Humans

KW - Insulin-Like Growth Factor I

KW - Male

KW - Patellar Ligament

KW - Protein Biosynthesis

KW - Young Adult

U2 - 10.1152/japplphysiol.01084.2013

DO - 10.1152/japplphysiol.01084.2013

M3 - Journal article

C2 - 24265284

SN - 8750-7587

VL - 116

SP - 42

EP - 46

JO - Journal of Applied Physiology

JF - Journal of Applied Physiology

IS - 1

ER -

Increase in tendon protein synthesis in response to insulin-like growth factor-I is preserved in elderly men

Abstract

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