Document Detail

From mechanical loading to collagen synthesis, structural changes and function in human tendon.
MedLine Citation:
PMID:  19706001     Owner:  NLM     Status:  MEDLINE    
The adaptive response of connective tissue to loading requires increased synthesis and turnover of matrix proteins, with special emphasis on collagen. Collagen formation and degradation in the tendon increases with both acute and chronic loading, and data suggest that a gender difference exists, in that females respond less than males with regard to an increase in collagen formation after exercise. It is suggested that estrogen may contribute toward a diminished collagen synthesis response in females. Conversely, the stimulation of collagen synthesis by other growth factors can be shown in both animal and human models where insulin-like growth factor 1 (IGF-I) and transforming growth factor-beta-1 (TGF-beta-1) expression increases to accompany or precede an increase in procollagen expression and collagen synthesis. In humans, it can be demonstrated that an increase in the interstitial concentration of TGF-beta, PGE2, IGF-I plus its binding proteins and interleukin-6 takes place after exercise. The increase in IGF-I expression in tendon includes the isoform that has so far been thought only to exist in skeletal muscle (mechano growth factor). The increase in IGF-I and procollagen expression showed a similar response whether the tendon was stimulated by concentric, isometric or eccentric muscle contraction, suggesting that strain rather that stress/torque determines the collagen-synthesis stimulating response seen with exercise. The adaptation time to chronic loading is longer in tendon tissue compared with contractile elements of skeletal muscle or the heart, and only with very prolonged loading are significant changes in gross dimensions of the tendon observed, suggesting that habitual loading is associated with a robust change in the size and mechanical properties of human tendons. An intimate interplay between mechanical signalling and biochemical changes in the matrix is needed in tendon, such that chemical changes can be converted into adaptations in the morphology, structure and material properties.
M Kjaer; H Langberg; K Heinemeier; M L Bayer; M Hansen; L Holm; S Doessing; M Kongsgaard; M R Krogsgaard; S P Magnusson
Publication Detail:
Type:  Journal Article; Review    
Journal Detail:
Title:  Scandinavian journal of medicine & science in sports     Volume:  19     ISSN:  1600-0838     ISO Abbreviation:  Scand J Med Sci Sports     Publication Date:  2009 Aug 
Date Detail:
Created Date:  2009-08-27     Completed Date:  2010-01-13     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9111504     Medline TA:  Scand J Med Sci Sports     Country:  Denmark    
Other Details:
Languages:  eng     Pagination:  500-10     Citation Subset:  IM    
Department of Orthopaedics, Institute of Sports Medicine, Bispebjerg Hospital, Copenhagen, Denmark.
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MeSH Terms
Actins / metabolism
Collagen / biosynthesis*
Dinoprostone / metabolism
Insulin-Like Growth Factor I / metabolism
Interleukin-6 / metabolism
Sex Factors
Somatomedins / metabolism
Tendon Injuries / rehabilitation
Tendons / anatomy & histology,  metabolism*,  pathology
Transforming Growth Factor beta / metabolism
Weight-Bearing / physiology*
Reg. No./Substance:
0/Actins; 0/Interleukin-6; 0/Somatomedins; 0/Transforming Growth Factor beta; 363-24-6/Dinoprostone; 67763-96-6/Insulin-Like Growth Factor I; 9007-34-5/Collagen

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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