title: The 3D structure of the collagen fibril network in human trabecular bone: relation to trabecular organization.
abstract: Trabecular bone is morphologically and functionally different from compact bone at the tissue level, but both are composed of lamellae at the micrometer-scale level. We present a three-dimensional study of the collagenous network of human trabecular lamellar bone from the proximal femur using the FIB-SEM serial surface view method. The results are compared to human compact lamellar bone of the femoral shaft, studied by the same method. Both demineralized trabecular and compact lamellar bone display the same overall structural organization, namely the presence of ordered and disordered materials and the confinement of the canalicular network to the disordered material. However, in trabecular bone lamellae a significant proportion of the ordered collagen fibril arrays is aligned with the long axis of the trabecula and, unlike in compact bone, is not related to the anatomical axis of the whole femur. The remaining ordered collagen fibrils are offset from the axis of a trabecula either by about 30° or 70°. Interestingly, at the tissue scale of millimeters, the most abundant angles between any two connected trabeculae - the inter-trabecular angles - center around 30° and 70°. This implies that within a framework of interconnected trabeculae the same lamellar structure will always have a significant component of the fibrils aligned with the long axes of connected trabeculae. This structural complementarity at different hierarchical levels presumably reflects an adaptation of trabecular bone to function.
authors.affiliation: Department of Structural Biology, Weizmann Institute of Science, Rehovot, Israel. Electronic address: natalie.reznikov@weizmann.ac.il.
authors.forename: Natalie
authors.initials: N
authors.lastname: Reznikov
authors.affiliation: Hunter College, City University of New York, NY, USA.
authors.forename: Hila
authors.initials: H
authors.lastname: Chase
authors.affiliation: Department of Structural Biology, Weizmann Institute of Science, Rehovot, Israel.
authors.forename: Vlad
authors.initials: V
authors.lastname: Brumfeld
authors.affiliation: Koret School of Veterinary Medicine, Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel.
authors.forename: Ron
authors.initials: R
authors.lastname: Shahar
authors.affiliation: Department of Structural Biology, Weizmann Institute of Science, Rehovot, Israel.
authors.forename: Steve
authors.initials: S
authors.lastname: Weiner
mesh_terms: D005260:Female; D005269:Femur / Q000033:anatomy & histology* / Q000000981:diagnostic imaging / Q000648:ultrastructure; D024022:Fibrillar Collagens / Q000737:chemistry* / Q000648:ultrastructure; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D008875:Middle Aged; D055114:X-Ray Microtomography; D055815:Young Adult
chemical_list: D024022:Fibrillar Collagens
keywords: Collagen array; FIB-SEM; Inter-trabecular angle; Lamella; Trabecular bone; µCT