Inflammatory reactions titanium

Allergic reactions to titanium can occur (13). Inflammatory reactions and contact sensitivity have been reported after insertion of titanium implants. Osseointegration of the implant tends to occur, but around the area there can be an intense inflammatory reaction and persistent irritation of soft tissues (SEDA-22, 250) (14,15). 

After insertion of wires of different metals into the epiphyseal region of rabbits and an exposure time of fifteen months, the histology showed different results. With materials of inert or biocompatible behaviour the cells in the vicinity of the implant were still supplied with blood, while the cells in the neighbourhood of toxic materials underwent an inflammatory reaction and died. A few elements (Cr, Co, Ni and V) have toxic effects and also have a relatively low polarization resistance. Ti and its alloys, Nb and Ta, which have a high polarization resistance, exhibit an inert behaviour. In between the materials were found which are capsu-lated. The results also show that not only the corrosion behaviour provided by the polarization resistance is responsible for the biocompatibility of the material exposed to the tissue. The steel 316L and the CoCr alloy, which have a polarization resistance similar to that of titanium, are encapsulated by a tissue membrane and their behaviour is not inert [13]. 

Neural tissue response to wear debris was evaluated by applying 4 mg of particles onto the epidura of New Zealand white rabbits (n = 50, total). Five groups of rabbits were tested (n = 10, each) (1) sham operation (control) (2) stainless steel 316LVM (3) titanium alloy (Ti-6A1-4V) (4) CoCr alloy and (5) UHMWPE. The particle sizes ranged between 0.5 and 10 microns in diameter and were verified to be endotoxin free prior to implantation. Animals were sacrificed at 3 and 6 months postoperatively. Even though there was evidence of a chronic inflammatory reaction for all of the particles, it appeared localized within the... 

Metal ions released from metal implants by osteoclastic bio-corrosion are distributed through- out the body and are eventually taken up by dendritic cells, the most potent anti-gen-presenting cells [14, 15, 18]. Besides changing phenotypic and functional properties of dendritic cells [18], metal ions complex with cellular proteins and peptides. In case of titanium, the ions form complexes with phosphorus-containing proteins and peptides (usually signaling molecules), nucleotides (DNA in the nuclease and RNA in the cytoplasm) and lipids (phospholipids of the cellular membranes) [15]. The new antigenic metal-peptides are presented by dendritic cells to specific T-lymphocytes that react and are activated [15]. The dendritic cells and activated T-lymphocytes accumulate in tissues with high metal concentrations, usually close to the metal implant, and form inflammatory reactions [7] that include secretion of inflammatory cytokines, such as TNF-a, TGF-b, interleukin-6 and interleukin-lb [19]. Most important is secretion of RANK-L by the activated T-lymphocytes, an essential factor for maturation, survival and function of osteoclasts [19]. 

In patients with SSc, Frank et al. (1993) found a slight decrease of IL-i basal secretion from monocytes in comparison with healthy volunteers, and no changes in IL-6 and tumor necrosis factor cx (TNFa) production. In monocyte-enriched cultures from healthy donors, a dose-dependent modulation of the cytokine pattern (IL-i a, IL-i 3, IL-6, TNFot) could be demonstrated after silica phagocytosis. Using titanium dioxide for phagocytosis, no comparable effects were observed. The impact of silica on cytokine secretion of monocytes might explain inflammatory tissue reactions and increased collagen synthesis in silica-associated SSc. 

G Voggenreiter, S Leiting, H Brauer et al. (2003) Immuno-inflammatory tissue reaction to stainless-steel and titanium plates used for internal fixation of long bones. Biomaterials 24 247-54... 

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