Increase in tendon protein synthesis in response to insulin-like growth factor-I is preserved in elderly men
| Autor: | Rie Harboe Nielsen, Michael Kjaer, Lars Holm, Katja M. Heinemeier, Nikolaj M Malmgaard-Clausen, Søren Reitelseder |
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| Rok vydání: | 2014 |
| Předmět: |
Adult
Male Aging medicine.medical_specialty Anabolism Physiology medicine.medical_treatment Growth hormone Young Adult Insulin-like growth factor Patellar Ligament Physiology (medical) Internal medicine medicine Protein biosynthesis Humans Insulin-Like Growth Factor I Aged business.industry Growth factor Protein turnover Fibroblasts Tendon Surgery medicine.anatomical_structure Endocrinology Protein Biosynthesis business |
| Zdroj: | Journal of Applied Physiology; Vol 116 Nielsen, R H, Holm, L, Malmgaard-Clausen, N M, Reitelseder, S, Heinemeier, K M & Kjaer, M 2014, ' Increase in tendon protein synthesis in response to insulin-like growth factor-I is preserved in elderly men ', Journal of Applied Physiology . |
| ISSN: | 1522-1601 8750-7587 |
| DOI: | 10.1152/japplphysiol.01084.2013 |
| Popis: | 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. |
| Databáze: | OpenAIRE |
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