Stimulation of neutrophil movement by metal ions

The interaction between corrosion products of metallic implants and the surrounding tissue is important in determining the biocompatibility of the implant, in particular the interaction of corrosion products with inflammatory cells such as neutrophils and macrophages. Such cells are capable of releasing enzymes and high-energy oxygen radicals which can damage the tissue. Clearly, any factors that influence cell movement to the implant site could influence the biocompatibility of the implant. The present study examined the influence that copper and nickel ions had on neutrophil locomotion. Both copper and nickel ions stimulated a proportion of the neutrophil population to take up a nonspherical morphology and to locomote. These metal ion stimulated cells have higher circularity values and move slower than neutrophils incubated with FMLP. For both FMLP and nickel ion stimulated cells, there is a correlation between the speed of neutrophil locomotion and neutrophil circularity; as the neutrophil circularity value decreases, the speed of locomotion increases.