Distribution, metabolism, excretion, and toxicity of implanted silver: a review

Abstract

Some implantable medical devices contain silver. We aimed to assess at what amount implanted silver becomes toxic. Silver was elevated in bodily fluids and tissues surrounding silver-containing implants. Silver released from implants also distributes to blood and other tissues; there is evidence to suggest silver can pass the blood-brain-barrier. Silver can be deposited as nano-sized particles in various tissues. Such particles, in addition to silver, often contain other elements too, e.g., selenium and sulfur. Silver released from implants seems to stay in the body for long periods (years). Reported excretion pathways following implantation are urinary and fecal ones. Reported toxicological effects were virtually all local reactions surrounding the implants. Argyria is a blue-gray discoloration of the skin due to deposited silver granules. Localized argyria has been described after the implantation of acupuncture needles and silver-coated prostheses, although the presence of silver was tested only for and shown in the former. Other toxicological effects include local tissue reactivity and examples of neurotoxic and vascular effects. We did not include genotoxicity studies in the present publication as we recently evaluated silver to be genotoxic. Carcinogenicity studies were absent. We conclude that local toxicity of implanted silver can be foreseen in some situations.

Keywords:

• Ag
• bone cement
• implant
• medical device
• nanoparticle
• prosthesis
• silver

Acknowledgements

The help of librarians Elizabeth Bengtsen and Rikke Nilsson in retrieving articles is greatly appreciated.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Notes

1 Dissolucytosis is the macrophage-mediated release of metal ions from metal surfaces (Larsen et al. 2007).

Additional information

Funding

The writing of this article was supported by the European Union’s Horizon 2020 research and innovation programme under [grant agreement 814426] (NanoInformaTIX).