title: Orbital fluid shear stress promotes osteoblast metabolism, proliferation and alkaline phosphates activity in vitro.
abstract: Prolonged disuse of the musculoskeletal system is associated with reduced mechanical loading and lack of anabolic stimulus. As a form of mechanical signal, the multidirectional orbital fluid shear stress transmits anabolic signal to bone forming cells in promoting cell differentiation, metabolism and proliferation. Signals are channeled through the cytoskeleton framework, directly modifying gene and protein expression. For that reason, we aimed to study the organization of Normal Human Osteoblast (NHOst) cytoskeleton with regards to orbital fluid shear (OFS) stress. Of special interest were the consequences of cytoskeletal reorganization on NHOst metabolism, proliferation, and osteogenic functional markers. Cells stimulated at 250 RPM in a shaking incubator resulted in the rearrangement of actin and tubulin fibers after 72 h. Orbital shear stress increased NHOst mitochondrial metabolism and proliferation, simultaneously preventing apoptosis. The ratio of RANKL/OPG was reduced, suggesting that orbital shear stress has the potential to inhibit osteoclastogenesis and osteoclast activity. Increase in ALP activity and OCN protein production suggests that stimulation retained osteoblast function. Shear stress possibly generated through actin seemed to hold an anabolic response as osteoblast metabolism and functional markers were enhanced. We hypothesize that by applying orbital shear stress with suitable magnitude and duration as a non-drug anabolic treatment can help improve bone regeneration in prolonged disuse cases.
authors.affiliation: Institute of Medical Molecular Biotechnology and Faculty of Medicine, Universiti Teknologi MARA, Sungai Buloh 47000, Selangor, Malaysia.
authors.forename: M D
authors.initials: MD
authors.lastname: Aisha
authors.affiliation: Institute of Medical Molecular Biotechnology and Faculty of Medicine, Universiti Teknologi MARA, Sungai Buloh 47000, Selangor, Malaysia; DDH, Universiti Teknologi MARA, ShahAlam 40450, Selangor, Malaysia.
authors.forename: M N K
authors.initials: MN
authors.lastname: Nor-Ashikin
authors.affiliation: DDH, Universiti Teknologi MARA, ShahAlam 40450, Selangor, Malaysia.
authors.forename: A B R
authors.initials: AB
authors.lastname: Sharaniza
authors.affiliation: Center for Pathology Diagnostic and Research Laboratories, Clinical Training Center, Universiti Teknologi MARA, Sungai Buloh 47000, Selangor, Malaysia; I-PPerForM, Universiti Teknologi MARA, Selayang 47000 Selangor, Malaysia.
authors.forename: H
authors.initials: H
authors.lastname: Nawawi
authors.affiliation: Institute of Medical Molecular Biotechnology and Faculty of Medicine, Universiti Teknologi MARA, Sungai Buloh 47000, Selangor, Malaysia; I-PPerForM, Universiti Teknologi MARA, Selayang 47000 Selangor, Malaysia. Electronic address: gabriele@salam.uitm.edu.my.
authors.forename: G R A
authors.initials: GR
authors.lastname: Froemming
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism; D001696:Biomechanical Phenomena; D016723:Bone Remodeling; D002454:Cell Differentiation; D049109:Cell Proliferation; D003599:Cytoskeleton / Q000378:metabolism / Q000648:ultrastructure; D006801:Humans; D010006:Osteoblasts / Q000201:enzymology*
chemical_list: D000469:Alkaline Phosphatase
keywords: Actin; Anabolic stimulus; Bone regeneration; Cytoskeleton; Mechanical loading; Normal Human Osteoblast cells; Orbital fluid shear stress; Osteoblastogenesis; tubulin