Local administration of insulin-like growth factor-I (IGF-I) stimulates tendon collagen synthesis in humans

Mette Hansen, Anders Boesen, Lars Holm, A Flyvbjerg, Henning Langberg, Michael Kjær

Research output: Contribution to journalArticlepeer-review

64 Citations (Scopus)


Collagen is the predominant structural protein in tendons and ligaments, and can be controlled by hormonal changes. In animals, injections of insulin-like growth factor I (IGF-I) has been shown to increase collagen synthesis in tendons and ligaments and to improve structural tissue healing, but the effect of local IGF-I administration on tendon collagen synthesis in human has not been studied. The purpose of this study was to study whether local injections of IGF-I would have a stimulating effect on tendon collagen synthesis. Twelve healthy nonsmoking men [age 62 ± 1 years (mean ± SEM), BMI 27 ± 1] participated. Two injections of either human recombinant IGF-I (0.1 mL Increlex©) or saline (control) into each patellar tendon were performed 24-h apart, respectively. Tendon collagen fractional synthesis rate (FSR) was measured by stable isotope technique in the hours after the second injection. Simultaneously, interstitial peritendinous (IGF-I) and [procollagen type I N-terminal propeptide (PINP)], as a marker for type I collagen synthesis, were determined by microdialysis technique. Tendon collagen FSR and PINP were significantly higher in the IGF-I leg compared with the control leg (P <0.05). In conclusion, local IGF-I administration can directly enhance tendon collagen synthesis both within and around the human tendon tissue.
Original languageEnglish
Pages (from-to)614-619
Number of pages6
JournalScandinavian Journal of Medicine and Science in Sports
Issue number5
Publication statusPublished - Oct 2013

Bibliographical note

© 2012 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.


  • Aged
  • Biological Markers
  • Collagen
  • Collagen Type I
  • Denmark
  • Double-Blind Method
  • Humans
  • Injections
  • Insulin-Like Growth Factor I
  • Male
  • Microdialysis
  • Middle Aged
  • Patellar Ligament
  • Sodium Chloride


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