title: Bone remodelling in humans is load-driven but not lazy.
abstract: During bone remodelling, bone cells are thought to add and remove tissue at sites with high and low loading, respectively. To predict remodelling, it was proposed that bone is removed below and added above certain thresholds of tissue loading and within these thresholds, called a 'lazy zone', no net change in bone mass occurs. Animal experiments linking mechanical loading with changes in bone density or microstructure support load-adaptive bone remodelling, while in humans the evidence for this relationship at the micro-scale is still lacking. Using new high-resolution CT imaging techniques and computational methods, we quantify microstructural changes and physiological tissue loading in humans. Here, we show that bone remodelling sites in healthy postmenopausal women strongly correlate with tissue loading following a linear relationship without a 'lazy zone' providing unbiased evidence for load-driven remodelling in humans. This suggests that human and animal bones both react to loading induced remodelling in a similar fashion.
authors.affiliation: Orthopaedic Biomechanics, Department of Biomedical Engineering, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands.
authors.forename: Patrik
authors.initials: P
authors.lastname: Christen
authors.affiliation: Orthopaedic Biomechanics, Department of Biomedical Engineering, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands.
authors.forename: Keita
authors.initials: K
authors.lastname: Ito
authors.affiliation: INSERM UMR 1033, Hôpital Edouard Herriot, Université de Lyon, 69437 Lyon, France.
authors.forename: Rafaa
authors.initials: R
authors.lastname: Ellouz
authors.affiliation: INSERM UMR 1033, Hôpital Edouard Herriot, Université de Lyon, 69437 Lyon, France.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Boutroy
authors.affiliation: INSERM UMR 1033, Hôpital Edouard Herriot, Université de Lyon, 69437 Lyon, France.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Sornay-Rendu
authors.affiliation: INSERM UMR 1033, Hôpital Edouard Herriot, Université de Lyon, 69437 Lyon, France.
authors.forename: Roland D
authors.initials: RD
authors.lastname: Chapurlat
authors.affiliation: Orthopaedic Biomechanics, Department of Biomedical Engineering, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands.
authors.forename: Bert
authors.initials: B
authors.lastname: van Rietbergen
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D016723:Bone Remodeling / Q000502:physiology*; D003198:Computer Simulation; D005260:Female; D006801:Humans; D008875:Middle Aged; D008954:Models, Biological; D017698:Postmenopause; D013314:Stress, Mechanical; D013977:Tibia / Q000000981:diagnostic imaging* / Q000502:physiology; D014057:Tomography, X-Ray Computed; D016474:Weight-Bearing / Q000502:physiology*