Argyria resulting from chronic use of colloidal silver in a patient presenting for colonoscopy

Occurrence of Silver-containing Particles in Rat Brains upon Intranasal Exposure of Silver Nanoparticles

The widespread application of silver nanomaterials raises health concerns due to the adverse effects that can be associated with silver nanoparticles (AgNPs) exposure. AgNPs can be introduced into human bodies via inhalation, either intentionally (intranasal administration of AgNPs) or unintentionally (environmental pollution, accidental release, or occupational exposure). Recent studies have shown that intranasal exposure of experimental animals to AgNPs can lead to the accumulation of silver (Ag) in brain tissues. However, there is little information available concerning what forms of Ag (particulate and ionic) exist in brain tissues. This study aimed to investigate whether particulate Ag exists in rat brains following intranasal exposure of AgNPs at 1 mg/kg/day using multiple analytical techniques. The results demonstrated that Ag-containing particles were presented in AgNPs-exposed rat brains, accounting for 20.2%- 68.1% of the total Ag. The mass concentrations of Ag-containing particles in brain tissues increased with exposure time but only decreased by 37.5% after elimination for 4 weeks upon exposure cessation. The size of Ag-containing particles identified in rat brains was larger than the original AgNPs. The Ag-containing particles identified in the rat brain were composed of multiple elements, including Ag, sulfur (S), selenium (Se) with atomic percentages of 45.8%, 37.5%, 16.7% respectively. The finding highlighted the occurrence and accumulation of transformed AgNPs containing S and Se in rat brains after intranasal exposure to AgNPs, implying potential risks for brain health.

Clinical and Forensic Aspects of the Different Subtypes of Argyria

Argyria encompasses the different cosmetic alterations that can develop if enough silver particles deposit in a specific tissue, typically in the skin, ranging from localized dark-blue macules to a generalized slate-gray/bluish tinge following systemic absorption. This work aims to fully review the state of the art regarding pathophysiology, diagnosis, treatment, and relevant clinical and forensic features of argyria. Argyria has been diagnosed in a wide range of ages, both sexes and varied ethnicities, with no known individual predisposing factors. Ultraviolet radiation with subsequence increases of melanin production aggravates the discoloration due to a reduction in the silver deposits. Physical examination and silver exposure in the anamnesis can be highly suggestive of the diagnosis, but a histopathological analysis with Energy-Dispersive X-ray Spectroscopy is required to unequivocally determine the discoloration etiology. Safe and effective treatment has only been accomplished with laser techniques, though only a few cases have been reported and with limited follow-up time. In conclusion, argyria typically has an occupational or iatrogenic etiology. It should be suspected when a patient presents with typical skin or eye lesions. A seemingly viable treatment modality, with laser technology, is finally within the horizon.

Acute myeloid leukemia with complex cytogenetic abnormalities associated with long-term use of oral colloidal silver as nutritional supplement – Case report and review of literature

We report a case of acute myeloid leukemia with complex cytogenetic abnormalities suggestive of preexisting myelodysplastic syndrome in a patient with habitual ingestion of colloidal silver as nutritional supplement for over 10 years and the medical literature is reviewed.

Brain-targeted distribution and high retention of silver by chronic intranasal instillation of silver nanoparticles and ions in Sprague-Dawley rats

The wide applications of silver nanoparticles (AgNPs) have been concerned regarding their unintentional toxicities. Different exposure modes may cause distinct accumulation, retention and elimination profiles, which are closely related with their toxicities. Unlike silver accumulation profiles through other regular administration modes, the biodistribution, accumulation and elimination of AgNPs by intranasal instillation are not fully understood. This study conducted intranasal instillation of polyvinylpyrrolidone-coated AgNPs in neonatal Sprague-Dawley rats at doses of 1 and 0.1 mg kg(-1) day(-1) for 4 and 12 weeks, respectively. The 4-week recovery was also designed after the 12-week exposure. Silver concentrations in the main tissues or organs were periodically monitored. Parallel exposures using silver ion were performed for the comparative studies. No physiological alterations were observed in AgNP exposures. In comparison, 1 mg kg(-1) day(-1) silver ions decreased body weight gain and caused mortality of 18.2%, showing ionic silver had a relatively higher toxicity than AgNPs. A relatively higher silver accumulation was observed in silver ion groups than AgNP groups. The silver ion release could not fully explain silver accumulation in AgNP exposures, showing silver distribution caused by particulate silver occurred in vivo. The highest silver concentration was in the liver at week 4, while it shifted to the brain after a 12-week exposure. Dose-related silver accumulation occurred for both AgNP and silver ion groups. The time course revealed a uniquely high concentration and retention of brain silver, implying chronic intranasal instillation caused brain-targeted silver accumulation. These findings provided substantial evidence on the potential neuronal threat from the intranasal administration of AgNPs or silver colloid-based products.