Woven bone overview: structural classification based on its integral role in developmental, repair and pathological bone formation throughout vertebrate groups

Abstract

Cortical bone development is characterised by initial formation of woven bone followed by deposition of lamellar bone on the woven scaffold. This occurs in normal bone formation as an integral obligate selfassembly pattern throughout all vertebrate groups, with specific temporal and spatial features. It also occurs in repair bone, modified by the biophysical/mechanical environment, and in pathological bone, modified by the specific disorder and its severity. Two spatially distinct osteoblast cell populations synthesise woven and lamellar bone: mesenchymal osteoblasts surround themselves circumferentially with collagen in a random array to form woven bone; surface osteoblasts align themselves in a linear array on the woven bone surface (or adjacent lamellar bone) to synthesise parallel-fibred lamellar bone. Four specific stages of woven bone formation are defined: stage I, early differentiation of pre-osteoblasts from undifferentiated mesenchymal cells; stage II, mesenchymal osteoblasts surrounding themselves in a 360° arc with randomly oriented matrix fibres; stage III, woven matrix acting as a scaffold on which surface osteoblasts begin to synthesise bone in parallel-fibred lamellar conformation; stage IV, progressive relative diminution of woven bone in the woven bone/lamellar bone complex. Stages II and IV are further subdivided (in a, b and c) by shifting cell area/matrix area and woven bone/lamellar bone relationships. The under-appreciated biological significance of woven bone is that it initiates formation de novo at sites of no previous bone. This information allows for targeted assessment of molecular-biophysical mechanisms underlying woven bone formation and their utilisation for initiating enhanced bone formation.

Hox genes maintain critical roles in the adult skeleton

“…In both cases, the initial woven bone matrix is remodeled and replaced by lamellar bone through a process that is not fully understood. The haphazard organization of collagen in the woven bone matrix causes the bone to be mechanically weak (32); therefore, the replacement of the woven bone matrix by lamellar bone is imperative for proper bone function and homeostasis. The accumulation of woven bone with no signs of lamellar remodeling in our Hox11 conditional mutants demonstrates that maintaining the integrity of the skeletal matrix requires Hox function.…”

Injectable bioactive glass-based pastes for potential use in bone tissue repair

“…It is well documented that fracture healing, being a complex biological process, normally includes acute inflammatory response, recruitment of mesenchymal stem cells (MSCs), generation of cartilaginous bony callus, mineralization, revascularization, and resorption of cartilaginous callus, and finally bone remodeling [49,50]. Shapiro and Wu, [50] revealed that as soon as a drilling defect through one cortex of the diaphysis of a young rabbit fe-mur was made, blood filled the space and fibrinous arcades formed within the blood clot across the defect from wall to wall; undifferentiated mesenchymal cells lay parallel to the fibrinous arcade, in conjunction with vascularization. The transformation from undifferentiated mesenchymal cells to a mesenchymal osteoblast, with increasing woven tissue synthesis, to a surface osteoblast synthesizing lamellar on woven bone, was found.…”

“…The transformation from undifferentiated mesenchymal cells to a mesenchymal osteoblast, with increasing woven tissue synthesis, to a surface osteoblast synthesizing lamellar on woven bone, was found. New bone formation beginning in the marrow advanced to the periphery of the defect while repair did not occur uniformly with the same tissue pattern across the entire defect and the central defect region healing last [50]. The woven bone is then remodeled into lamellar bone over the course of months to years, which allows for restoration of the canal and its bony properties [50].…”

Histopathology of osteogenesis imperfecta bone. Supramolecular assessment of cells and matrices in the context of woven and lamellar bone formation using light, polarization and ultrastructural microscopy

“…Structural studies have become infrequent other than formalized histomorphometry on iliac crest bone biopsies. We previously defined a positional and functional difference in osteoblasts referred to as mesenchymal osteoblasts (MOBLs) that synthesize woven bone and surface osteoblasts (SOBLs) that synthesize lamellar bone ( Shapiro, 1988 ; Shapiro, 2008 ; Shapiro and Wu, 2019 ). The terms static and dynamic osteogenesis refer to the same phenomenon ( Ferretti et al, 2002 ).…”

“…The terms static and dynamic osteogenesis refer to the same phenomenon ( Ferretti et al, 2002 ). We recognize a universal sequence of woven to lamellar bone formation by MOBLs and SOBLs respectively in the synthesis of normal, repair and pathologic bone ( Shapiro and Wu, 2019 ). OI bone is assessed i) in the context of MOBLs and SOBLs forming woven and lamellar bone conformations respectively and ii) as a molecular disorder based on abnormalities affecting collagen synthesis.…”