title: Revisiting the links between bone remodelling and osteocytes: insights from across phyla.
abstract: We question two major tenets of bone biology: that the primary role of remodelling is to remove damage in the bone (so-called damage-driven remodelling) and that osteocytes are the only strain-sensing orchestrators of this process. These concepts are distilled largely from research on model mammal species, but in fact, there are a number of features of various bones, from mammalian and non-mammalian species, that do not accord with these 'rules'. Here, we assemble a variety of examples, ranging from species that lack osteocytes but that still seem capable of remodelling their bones, to species with osteocytic bones that do not remodel, and to instances of inter-species, inter-bone and/or intra-bone variation in bone remodelling that show that this purported repair process is not always where the 'rules' tell us it should be. This collection of points argues that our understanding of the advantages, roles and primary drivers of remodelling are inadequate and biased to quite a small phylogenetic cross section of the species that possess bone. We suggest a variety of new directions for bone research that would provide us with a better understanding of bone remodelling, tying together the interests of comparative biologists, palaeontologists and medical researchers.
authors.affiliation: Department of Biology, University of York, York, YO10 5DD, U.K.
authors.forename: John D
authors.initials: JD
authors.lastname: Currey
authors.affiliation: Department Biomaterials, Max Planck Institute of Colloids & Interfaces, 14424, Potsdam, Germany.
authors.forename: Mason N
authors.initials: MN
authors.lastname: Dean
authors.affiliation: Koret School of Veterinary Medicine, Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, 76100, Israel.
authors.forename: Ron
authors.initials: R
authors.lastname: Shahar
mesh_terms: D000818:Animals; D016723:Bone Remodeling / Q000502:physiology*; D001842:Bone and Bones / Q000166:cytology / Q000378:metabolism; D010011:Osteocytes / Q000166:cytology / Q000502:physiology*; D010802:Phylogeny; D012106:Research / Q000639:trends
keywords: anosteocytic bone; bone remodelling; microcrack; osteoblast; osteoclast; osteocyte