Cancellous Skeleton, Microskeleton, Ultramicroskeleton: A Geo/Biomorphological Bone Mineral Microbiome of Hierarchical Force Translation and Ancient Golgi-Directed Lineage

Abstract

Bone minerals may be more complex than the prevailing opinion suggests. Understanding its biomaterial properties in health and disease may address fundamental geo/biomorphological ambiguities recurrent within its calcified cancellous hierarchy of macro-, micro-, and nano-skeletal networks. (i) There is evidence that the outer mineral macroskeleton of interconnected trabeculae (150 µm diameter) is modulated according to axes of tensile stress by permeating arrays of periosteal Sharpey’s fibres (collagen type III/VI, 5–25 µm thick) studded with tenascin organiser protein. (ii) Its substructural mineral microskeleton is a reticulation of bridged and deformable calcium phosphate/carbonate microspheres (about 1 µm diameter). These organically enshrouded (e.g., bone sialoprotein, osteocalcin, osteopontin) objects, configured by the adhesive organiser protein fibronectin and tempered by trace elements (e.g., Si, Mg, Fe, Al), display differential histochemistry (e.g., acid phosphatase, carbonic anhydrase) and anomalous traits (tetracycline binding, gram-positive microbial staining and nucleic acid staining affinity). The calcified microspheres are intracellular fabrications of osteocyte cohorts developed within “switched on” Golgi cisternae prior to aggregation at the extracellular calcification front in chains and looped assemblies. (iii) Within each microsphere, a less dense centre is encircled by a mineral nanoskeleton of beaded filaments (5 nm in diameter) transmutable in electron density, with a trait for lateral fusion into ladder-like struts, stays and senescent fenestrated plates, constituting domains of microparticle slip and crystal fracture. The evidence suggests a bone mineral biosystem of integrated complexity within which a particulate assemblage at the animate: inanimate calcification front resembles a colonial construct of prokaryote-like, Golgi-fabricated objects calcified with phosphate and harbouring a resident biochemistry. A self-contained “Petrified Microbiome” is proposed to be orchestrated according to a biodynamic primordial paradigm.