Mechanisms of magnesium‐stimulated adhesion of osteoblastic cells to commonly used orthopaedic implants

Abstract

Poor cell adhesion to orthopaedic and dental implants may result in implant failure. Cellular adhesion to biomaterial surfaces primarily is mediated by integrins, which act as signal transduction and adhesion proteins. Because integrin function depends on divalent cations, we investigated the effect of magnesium ions modified bioceramic substrata (Al(2)O(3)-Mg(2+)) on human bone-derived cell (HBDC) adhesion, integrin expression, and activation of intracellular signalling molecules. Immunohistochemistry, flow cytometry, cell adhesion, cell adhesion blocking, and Western blotting assays were used. Our findings demonstrated that adhesion of HBDC to Al(2)O(3)-Mg(2+) was increased compared to on the Mg(2+)-free Al(2)O(3). Furthermore, HBDC adhesion decreased significantly when the fibronectin receptor alpha5beta1- and beta1-integrins were blocked by functional blocking antibodies. HBDC grown on the Mg(2+)-modified bioceramic expressed significantly enhanced levels of beta1-, alpha5beta1-, and alpha3beta1-integrins receptors compared to those grown on the native unmodified Al(2)O(3). Tyrosine phosphorylation of intracellular integrin-dependent signalling proteins as well as the expression of key signalling protein Shc isoforms (p46, p52, p66), focal adhesion kinase, and extracellular matrix protein collagen type I were significantly enhanced when HBDC were grown on Al(2)O(3)-Mg(2+) compared to the native Al(2)O(3). We conclude that cell adhesion to biomaterial surfaces is probably mediated by alpha5beta1- and beta1-integrin. Cation-promoted cell adhesion depends on 5beta1- and beta1-integrins associated signal transduction pathways involving the key signalling protein Shc and results also in enhanced gene expression of extracellular matrix proteins. Therefore, Mg(2+) supplementation of bioceramic substrata may be a promising way to improve integration of implants in orthopaedic and dental surgery.

Biocompatibility and bioactivity of porous polymer-derived Ca-Mg silicate ceramics

“…23 The present study explored the cellular response of MC3T3 pre-osteoblast cells to the 24 two Ca-Mg-rich ceramics. Cytotoxicity was tested in accordance to the ISO10993-5 and grinding with mortar and pestle to below 100 μm, by X-ray diffraction (XRD; Bruker AXS 23 D8 Advance, Bruker, Germany; CuKα radiation, 0.15418 nm, 40 kV-40 mA, 2θ = 10°-70°, 24 step size = 0.05°, 2 s counting time), supported by data from PDF-2 database (ICDD-International Centre for Diffraction Data, Newtown Square, PA) and Match!…”

“…Dissolution products released by the samples (0.2 g ml -1 in α- 22 MEM at 37 °C) over a 72 h period were prepared. Medical grade polyethylene (PE) was used 23 as non-cytotoxic negative control and polyurethane (PU) containing 0.1% (w/w) zinc 24 diethyldithiocarbamate (ZDEC) was used as toxic positive control. The dissolution products were filter sterilised and dilution series (25%, 50%, 75% and 100%) were prepared and 1 supplemented with 10% (v/v) foetal calf serum (FCS) prior to use.…”

“…1a,c). One likely reason is 23 represented by the composition of silicone-based mixtures: the higher silica content of WD samples resulted in a higher silicone:filler ratio and a consequently lower viscosity of pastes 1 upon the foaming step. Pore diameters were between 700 μm and 1 mm (Fig.…”

“…that Mg is a promising agent in skeletal tissue engineering applications due to its ability to 16 stimulate new bone formation [23]. Mg was suggested to interact with integrins of osteoblasts 17 that are responsible for cell adhesion and stability [23,50]. The importance of Mg in bone [25,51,52].…”

Quantitative analyses of Streptococcus mutans biofilms with quartz crystal microbalance, microjet impingement and confocal microscopy

“…In recent years, sophisticated techniques such as atomic force microscopy, microcantilever, spinning disk device, and micromanipulation have been developed to measure the adhesive strength of monolayer eukaryotic cells on substrates or bacterial electrosteric interactions (Yamamoto et al, 1998;Cargill et al, 1999;Camesano & Logan, 2000;Zreiqat et al, 2002;Poppele & Hozalski, 2003). Owing to high technical demands, these techniques have not found wide application in the laboratories.…”