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The influence of age on adaptive bone formation and bone resorption
Publikationstyp
Journal Article
Date Issued
2014-11
Sprache
English
Author(s)
Birkhold, Annette I.
Razi, Hajar
Journal
Volume
35
Issue
34
Start Page
9290
End Page
9301
Citation
Biomaterials 35 (34): 9290-9301 (2014)
Publisher DOI
Scopus ID
Publisher
Elsevier
Bone is a tissue with enormous adaptive capacity, balancing resorption and formation processes. It is known that mechanical loading shifts this balance towards an increased formation, leading to enhanced bone mass and mechanical performance. What is not known is how this adaptive response to mechanical loading changes with age. Using dynamic micro-tomography, we show that structural adaptive changes of trabecular bone within the tibia of living mice subjected to two weeks of invivo cyclic loading are altered by aging. Comparisons of 10, 26 and 78 weeks old animals reveal that the adaptive capacity diminishes. Strikingly, adaptation was asymmetric in that loading increases formation more than it reduces resorption. This asymmetry further shifts the (re)modeling balance towards a net bone loss with age. Loading results in a major increase in the surface area of mineralizing bone. Interestingly, the resorption thickness is independent of loading in trabecular bone in all age groups. This data suggests that during youth, mechanical stimulation induces the recruitment of bone modeling cells whereas in old age, only bone forming cells are affected. These findings provide mechanistic insights into the processes that guide skeletal aging in mice as well as in other mammals.
Subjects
Adaptation
Aging
Bone remodeling
Image analysis
Microstructure
DDC Class
610: Medicine, Health