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Integrin αv signaling influences phenotype and maturation of primary human osteoblasts on alumina surface

Wróbel E., Witkowska-Zimny M., Mrówka P., Głodkowska-Mrówka E.

Engineering of Biomaterials

2014

Vol. 17, no. 127

33--39

Due to the growing interest in stem cells application in tissue engineering the better understanding of primary human osteoblasts behavior in vitro, on biomaterial surface, is required. Among other molecules integrins may be taken into account as being involved in these phenomena. Integrins are a family of cell adhesion receptors, which may regulate many cellular functions e.g., adhesion, motility, phenotype and cell maturation. The aim of this study was to determine the effect of the biomaterial surfaces and αv integrin signaling pathway on the behavior, phenotype and maturation of human osteoblasts in vitro. Human bone derived cells (HBDCs) obtained from adult femoral bone fragments were cultured on both alumina disks and tissue culture polystyrene (TCPS) dishes. After 7, 14, and 21 days of culture, localization and mRNA expression level of αv integrin subunits and BGLAP (osteocalcin) on polystyrene were analyzed in addition, we treated the cell cultures with monoclonal antibodies against human αv integrin to block its ligand-binding activity, on both alumina and TCPS substrates. We found that the αv integrin was present in focal contacts and cell cytoplasm at subsequent stages of cell maturation and the level of αv integrin mRNA was the highest in mature osteoblasts. Blocking αv integrin transduction pathway caused changes in cell activity and morphology, decreased cells proliferation on TCPS and reduced expression of alkaline phosphatase (ALP) on both materials. The results suggest that αv integrin is involved as an important receptor facilitating osteogenic differentiation.

Bone remodeling and bone adaptation

Petrtyl M., Danesova J.

Acta of Bioengineering and Biomechanics

1999

Vol. 1, nr 1

107-116

Bone remodelling is a very complicated process that can be characterised as close relationship of biomechnical effects and biomechanical reactions. It is not possible to give an exact definition of the bone remodeling if we take into consideration the aspects related merely to biomechanics or to biochemistry. Biomechanical processes in a remodelled bone tissue depend on the dominant force and moment effects or on the stress and strain state of the tissue. The stress (strain) tensors initiate and govern the rate of biochemical remodelling processes. The paper presented deals with fundamental stoichiometric equations of bone remodelling, kinetic equations of remodelling and rate constants of remodelling. The rates of bone remodelling depend on mechanical effects or on stress (strain) tensors. The spherical stress tensor controls the rate of biomechanical remodelling reactions, while the deviator of a stress (strain) tensor initiates biomechanical reactions. The micro-strains cause the flow of a liquid in the extra-celluar space of osteocytes and initiate the receptor activity of integrins A,B, The micro-strains of a mineralised matrix and the flow of an extra-cellular liquid result, for example in the production of prostaglandin E2 and in the subsquent resorption of a bone tissue.