title: Multi-level characterization of human femoral cortices and their underlying osteocyte network reveal trends in quality of young, aged, osteoporotic and antiresorptive-treated bone.
abstract: Characterization of bone's hierarchical structure in aging, disease and treatment conditions is imperative to understand the architectural and compositional modifications to the material and its mechanical integrity. Here, cortical bone sections from 30 female proximal femurs - a frequent fracture site - were rigorously assessed to characterize the osteocyte lacunar network, osteon density and patterns of bone matrix mineralization by backscatter-electron imaging and Fourier-transform infrared spectroscopy in relation to mechanical properties obtained by reference-point indentation. We show that young, healthy bone revealed the highest resistance to mechanical loading (indentation) along with higher mineralization and preserved osteocyte-lacunar characteristics. In contrast, aging and osteoporosis significantly alter bone material properties, where impairment of the osteocyte-lacunar network was evident through accumulation of hypermineralized osteocyte lacunae with aging and even more in osteoporosis, highlighting increased osteocyte apoptosis and reduced mechanical competence. But antiresorptive treatment led to fewer mineralized lacunae and fewer but larger osteons signifying rejuvenated bone. In summary, multiple structural and compositional changes to the bone material were identified leading to decay or maintenance of bone quality in disease, health and treatment conditions. Clearly, antiresorptive treatment reflected favorable effects on the multifunctional osteocytic cells that are a prerequisite for bone's structural, metabolic and mechanosensory integrity.
authors: Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Lottestrasse 59, 22529 Hamburg, Germany; Laboratory for Anthropology, Institute of Anatomy, Faculty of Medicine, University of Belgrade, Dr Subotica 4/2, 11000 Belgrade, Serbia.
authors: Petar
authors: P
authors: Milovanovic
authors: Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Lottestrasse 59, 22529 Hamburg, Germany.
authors: Elizabeth A
authors: EA
authors: Zimmermann
authors: Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Lottestrasse 59, 22529 Hamburg, Germany.
authors: Christoph
authors: C
authors: Riedel
authors: Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Lottestrasse 59, 22529 Hamburg, Germany.
authors: Annika
authors: A
authors: vom Scheidt
authors: Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Lottestrasse 59, 22529 Hamburg, Germany.
authors: Lydia
authors: L
authors: Herzog
authors: Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Lottestrasse 59, 22529 Hamburg, Germany.
authors: Matthias
authors: M
authors: Krause
authors: Laboratory for Anthropology, Institute of Anatomy, Faculty of Medicine, University of Belgrade, Dr Subotica 4/2, 11000 Belgrade, Serbia.
authors: Danijela
authors: D
authors: Djonic
authors: Laboratory for Anthropology, Institute of Anatomy, Faculty of Medicine, University of Belgrade, Dr Subotica 4/2, 11000 Belgrade, Serbia.
authors: Marija
authors: M
authors: Djuric
authors: Department of Forensic Medicine, University Medical Center Hamburg-Eppendorf, Butenfeld 34, 22529 Hamburg, Germany.
authors: Klaus
authors: K
authors: Püschel
authors: Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Lottestrasse 59, 22529 Hamburg, Germany.
authors: Michael
authors: M
authors: Amling
authors: Department of Materials Science and Engineering, University of California, Berkeley, USA; Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley CA 94720, USA.
authors: Robert O
authors: RO
authors: Ritchie
authors: Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Lottestrasse 59, 22529 Hamburg, Germany; Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley CA 94720, USA. Electronic address: b.busse@uke.uni-hamburg.de.
authors: Björn
authors: B
authors: Busse
mesh_terms: D000328:Adult; D000369:Aged, 80 and over; D000375:Aging / Q000473:pathology*; D015519:Bone Density / Q000187:drug effects; D050071:Bone Density Conservation Agents / Q000494:pharmacology / Q000627:therapeutic use*; D001857:Bone Matrix / Q000187:drug effects / Q000473:pathology / Q000503:physiopathology; D001862:Bone Resorption / Q000188:drug therapy* / Q000473:pathology / Q000503:physiopathology; D002113:Calcification, Physiologic / Q000187:drug effects; D004583:Electrons; D005260:Female; D005269:Femur / Q000187:drug effects / Q000473:pathology* / Q000503:physiopathology; D006253:Haversian System / Q000187:drug effects / Q000473:pathology / Q000503:physiopathology; D006801:Humans; D010011:Osteocytes / Q000187:drug effects / Q000473:pathology*; D010024:Osteoporosis / Q000473:pathology*; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D050071:Bone Density Conservation Agents
keywords: Biomineralization; Bone; Fracture mechanism; Mechanical properties; Microstructure; Osteoporosis