Document Detail

Decorin expression is important for age-related changes in tendon structure and mechanical properties.
MedLine Citation:
PMID:  23178232     Owner:  NLM     Status:  MEDLINE    
The aging population is at an increased risk of tendon injury and tendinopathy. Elucidating the molecular basis of tendon aging is crucial to understanding the age-related changes in structure and function in this vulnerable tissue. In this study, the structural and functional features of tendon aging are investigated. In addition, the roles of decorin and biglycan in the aging process were analyzed using transgenic mice at both mature and aged time points. Our hypothesis is that the increase in tendon injuries in the aging population is the result of altered structural properties that reduce the biomechanical function of the tendon and consequently increase susceptibility to injury. Decorin and biglycan are important regulators of tendon structure and therefore, we further hypothesized that decreased function in aged tendons is partly the result of altered decorin and biglycan expression. Biomechanical analyses of mature (day 150) and aged (day 570) patellar tendons revealed deteriorating viscoelastic properties with age. Histology and polarized light microscopy demonstrated decreased cellularity, alterations in tenocyte shape, and reduced collagen fiber alignment in the aged tendons. Ultrastructural analysis of fibril diameter distributions indicated an altered distribution in aged tendons with an increase of large diameter fibrils. Aged wild type tendons maintained expression of decorin which was associated with the structural and functional changes seen in aged tendons. Aged patellar tendons exhibited altered and generally inferior properties across multiple assays. However, decorin-null tendons exhibited significantly decreased effects of aging compared to the other genotypes. The amelioration of the functional deficits seen in the absence of decorin in aged tendons was associated with altered tendon fibril structure. Fibril diameter distributions in the decorin-null aged tendons were comparable to those observed in the mature wild type tendon with the absence of the subpopulation containing large diameter fibrils. Collectively, our findings provide evidence for age-dependent alterations in tendon architecture and functional activity, and further show that lack of stromal decorin attenuates these changes.
Andrew A Dunkman; Mark R Buckley; Michael J Mienaltowski; Sheila M Adams; Stephen J Thomas; Lauren Satchell; Akash Kumar; Lydia Pathmanathan; David P Beason; Renato V Iozzo; David E Birk; Louis J Soslowsky
Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural     Date:  2012-11-23
Journal Detail:
Title:  Matrix biology : journal of the International Society for Matrix Biology     Volume:  32     ISSN:  1569-1802     ISO Abbreviation:  Matrix Biol.     Publication Date:  2013 Jan 
Date Detail:
Created Date:  2013-02-11     Completed Date:  2013-07-25     Revised Date:  2014-01-09    
Medline Journal Info:
Nlm Unique ID:  9432592     Medline TA:  Matrix Biol     Country:  Netherlands    
Other Details:
Languages:  eng     Pagination:  3-13     Citation Subset:  IM    
Copyright Information:
Copyright © 2012 Elsevier B.V. All rights reserved.
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MeSH Terms
Aging / physiology*
Biglycan / metabolism*
Biomechanical Phenomena
Decorin / metabolism*
Elastic Modulus
Fibrillar Collagens / physiology*
Gene Expression Regulation, Developmental / physiology*
Histological Techniques
Mice, Transgenic
Patellar Ligament / metabolism,  physiology*
Tendon Injuries / metabolism,  physiopathology*
Grant Support
Reg. No./Substance:
0/Biglycan; 0/Decorin; 0/Fibrillar Collagens

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