PubMed Health⌕ Search

PubMed · 17100746

Inflammatory response to a titanium surface with potential bioactive properties: an in vitro study.

Abstract

BACKGROUND: The current hard tissue implants research aims to accelerate bone healing by designing surfaces that are bioactive. However, the role of the inflammatory response to these surfaces is so far incompletely described. PURPOSE: The aim of the study was to evaluate early inflammatory response in vitro to a potentially bioactive surface--an anodized surface with Mg ions incorporated (anodized/Mg)--and to compare it to a turned, a blasted, and an anodized surface. MATERIALS AND METHODS: An interferometer was used for topographical characterizations. The disks were incubated with human mononuclear cells. Adherent cells were investigated with respect to number of cells, viability, differentiation, and cytokine production with and without lipopolysaccharide stimulation after 24 and 72 hours. RESULTS: The number of adhered mononuclear cells differed significantly between the different modified surfaces, with the highest number on the anodized surface. However, there were no significant differences in cytokine production and differentiation between the different modified surfaces. The amount of anti-inflammatory mediator interleukin-10 remained over time, while the number of cells and pro-inflammatory cytokine tumor necrosis factor-alpha decreased. The cells were viable on all surfaces, respectively. CONCLUSION: The anodized surfaces with and without Mg ions showed an increased cell adherence, however, otherwise an inflammatory response similar to the turned and blasted surfaces. Furthermore, the potentially bioactive anodized/Mg surface showed a similar response to the TiUnite-like anodized surface despite the former having a surface roughness of a smoother character.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Anna Göransson, Christina Gretzer, Anna Johansson, Young-Taeg Sul, Ann Wennerberg. 2006. Inflammatory response to a titanium surface with potential bioactive properties: an in vitro study.. https://doi.org/10.1111/j.1708-8208.2006.00021.x

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

Nanotopographical stimulation of mechanotransduction and changes in interphase centromere positioning.

We apply a recently developed method for controlling the spreading of cultured cells using electron beam lithography (EBL) to create polymethylmethacrylate (PMMA) substrata with repeating nanostructures. There are indications that the reduced cell spreading on these substrata, compared with planar PMMA, results from a reduced adhesivity since there are fewer adhesive structures and fewer of their associated stress fibres. The reduced cell spreading also results in a reduced nuclear area and a closer spacing of centrosomes within the nucleus, suggesting that the tension applied to the nucleus is reduced as would be expected from the reduction in stress fibres. In order to obtain further evidence for this, we have used specific inhibitors of components of the cytoskeleton and have found effects comparable with those induced by the new substrata. We have also obtained evidence that these subtrata result in downregulation of gene expression which suggests that this may be due to the changed tension on the nucleus: an intriguing possibility that merits further investigation.

Cell Adhesion↗

BIG1, a brefeldin A-inhibited guanine nucleotide-exchange protein, is required for correct glycosylation and function of integrin beta1.

Glycosylation of beta1 integrin (beta1) in the Golgi complex has been related to its function in multiple cell processes, e.g., invasiveness, matrix adhesion, and migration. Brefeldin A-inhibited guanine nucleotide-exchange proteins (BIG) 1 and BIG2 activate human ADP-ribosylation factors (ARF) 1 and ARF3 by catalyzing the replacement of ARF-bound GDP with GTP to regulate Golgi vesicular transport. We show here a requirement for BIG1 (but not BIG2) in glycosylation and function of beta1. In HepG2 cells treated for 48 or 72 h with BIG1, but not BIG2, siRNA, both the amount and electrophoretic mobility of the initially 130-kDa beta1 were increased. BIG1 content had risen by 48 h after removal of BIG1 siRNA, and the faster-migrating, aberrant 130-kDa beta1 was not seen. Peptide N-glycosidase F, but not endoglycosidase H, digestion converted all beta1 to an approximately 85-kDa (core protein) form. By electron microscopy, Golgi membranes in BIG1-depleted cells were less sharply defined than those in mock or BIG2 siRNA-treated cells, with more vesicle-like structures at the transface. Amounts of active RhoA-GTP also were decreased in such cells and restored by overexpression of HA-BIG1. Aberrant beta1 was present on the cell surface, but its function in cell spreading, adhesion, and migration was impaired. By immunofluorescence microscopy, BIG1 siRNA-treated cells showed less spreading and concentration of beta1 at the cell surface. These results indicate a previously unrecognized role for BIG1 in the glycosylation of beta1 by Golgi enzymes, which is critical for its function in developmental and other vital cell processes.

Cell Adhesion↗

Signaling requirements for translocation of P-Rex1, a key Rac2 exchange factor involved in chemoattractant-stimulated human neutrophil function.

PI 3,4,5-trisphosphate [PI(3,4,5)P3; PIP3]-dependent Rac exchanger 1 (P-Rex1) is a Rac-specific guanine nucleotide exchange factor abundant in neutrophils and myeloid cells. As a selective catalyst for Rac2 activation, P-Rex1 serves as an important regulator of human neutrophil NADPH oxidase activity and chemotaxis in response to a variety of extracellular stimuli. The exchange activity of P-Rex1 is synergistically activated by the binding of PIP3 and betagamma subunits of heterotrimeric G proteins in vitro, suggesting that the association of P-Rex1 with membranes is a prerequisite for cellular activation. However, the spatial regulation of endogenous P-Rex1 has not been well defined, particularly in human neutrophils activated through G protein-coupled receptors. Upon stimulation of neutrophil chemoattractant receptors, we observed that P-Rex1 translocated from cytoplasm to the leading edge of polarized cells in a G protein betagamma subunit- and PIP3-dependent manner, where it colocalized with F-actin and its substrate, Rac2. Redistribution of P-Rex1 to the leading edge was also dependent on tyrosine kinase activity and was modulated by cell adhesion. Furthermore, we observed that activation of cAMP-dependent protein kinase A (PKA), which phosphorylates and inactivates P-Rex1, inhibited its translocation. Our data indicate that endogenous P-Rex1 translocates to areas of Rac2 and cytoskeletal activation at the leading edge in response to chemoattractant stimuli in human neutrophils and that this translocation can be negatively modulated by activation of PKA and by cell adhesion.

Cell Adhesion↗