Elevated fecal silver, lithium, and platinum in cognitive impairment: A pilot exploration of microbiota-metal interactions

Identifier:  imarina:9514399

Handle: https://hdl.handle.net/20.500.11797/imarina9514399

Authors:  Mateo, David; Souza, Marilia Cristina Oliveira; Carrion, Nerea; Heredia, Luis; Cabrera, Cristian; Marques, Montse; Forcadell-Ferreres, Eva; Pino, Maria; Zaragoza, Josep; Domingo, Jose Luis; Barbosa, Fernando; Torrente, Margarita

Abstract:
Background: Gut microbiota (GMB) and metal exposure have both been implicated in cognitive impairment (CI), including amnestic mild cognitive impairment (aMCI) and Alzheimer's disease (AD). However, studies integrating these areas remain scarce. Objective: This pilot study aimed to investigate whether exposure to metals modulates the relationship between GMB composition and clinical outcomes in individuals with CI. Methods: Stool samples were collected from aMCI (n =12), AD (n =18), and cognitively healthy controls (HC, n = 30). Participants were categorized into CI (n = 30) and HC (n = 30). Gut microbial diversity was assessed using shotgun sequencing, and 25 metals were quantified by inductively coupled plasma mass spectrometry (ICP-MS). Cognitive, neuropsychological, neuropsychiatric, and functional assessments were also conducted. Results: No significant differences were observed between groups in microbial richness, alpha-diversity (Shannon index), or beta-diversity (Bray-Curtis). Likewise, microbial diversity measures were not associated with cognitive outcomes. In contrast, aMCI and AD participants exhibited significantly higher fecal concentrations of silver (Ag), lithium (Li), and platinum (Pt) compared to HC (all p < 0.001). Conclusion: This multidimensional pilot study integrating microbiota profiling, metal exposure assessment, and cognitive evaluation, revealed elevated fecal excretion of Ag, Li, and Pt in participants with cognitive impairment, suggesting potential interactions between trace metals and neurodegenerative processes. While no significant differences in overall microbial diversity were observed between groups, these findings emphasize the need for larger, longitudinal investigations to elucidate the complex relationships among gut microbiota, metal homeostasis, and cognitive decline.