Impact pattern of heavy metals on gut microbiota in the polluted city of Tehran

Seyed Mahmoud  Barzi; Peyman  Naderi; Fatemeh Haririzadeh  Jouriani; Mahdi  Torkamaneh; Seyed Davar  Siadat; Farnaz  Shamkani; Seifoddin  Javadian; Mina  Ebrahimi-Rad; Mina  Ebrahimi-Rad; Reza  Saghiri; Seyed Ali  Nojoumi

doi:10.18502/ijm.v18i2.21295

Seyed Mahmoud Barzi Department of Bacteriology, Pasteur Institute of Iran, Tehran, Iran
Peyman Naderi Department of Biochemistry and Biophysics, Faculty of Advanced Sciences and Technology Tehran Medical Sciences, Islamic Azad University, Tehran, Iran
Fatemeh Haririzadeh Jouriani Department of Bacteriology, Pasteur Institute of Iran, Tehran, Iran
Mahdi Torkamaneh Department of Bacteriology, Pasteur Institute of Iran, Tehran, Iran
Seyed Davar Siadat Department of Mycobacteriology and Pulmonary Research, Pasteur Institute of Iran, Tehran, Iran
Farnaz Shamkani Department of Bacteriology, Pasteur Institute of Iran, Tehran, Iran
Seifoddin Javadian Department of Biochemistry, Pasteur Institute of Iran, Tehran, Iran
Mina Ebrahimi-Rad Department of Biochemistry, Pasteur Institute of Iran, Tehran, Iran
Mina Ebrahimi-Rad Department of Biochemistry, Pasteur Institute of Iran, Tehran, Iran
Reza Saghiri Department of Biochemistry, Pasteur Institute of Iran, Tehran, Iran
Seyed Ali Nojoumi Department of Mycobacteriology and Pulmonary Research, Pasteur Institute of Iran, Tehran, Iran

DOI: https://doi.org/10.18502/ijm.v18i2.21295

Keywords: Gastrointestinal microbiome; Heavy metals; Environmental pollution; Bacteria; Iran

Abstract

Background and Objectives: This article focuses on the effects of six heavy metals on gut microbiota, which plays a key role in human health. Gut microbiota plays a key role in metabolism, immunity, and maintaining homeostasis. Heavy metals can affect microbiota composition and function, with health consequences. Consuming large amounts of heavy metals may have harmful impacts, including alteration in microbial composition and bacterial population changes.

Materials and Methods: Six heavy metals—cadmium, chromium (toxic metals), copper, zinc, iron, and selenium (benefi- cial trace elements)—were detected in peripheral blood, serum, or urine, while feces were used for 16S rRNA sequencing. Serum samples from 100 volunteers from Tehran (polluted area) and Firoozkooh (clean city) were collected. Subjects were analyzed for the presence of Escherichia coli, Bacteroides fragilis, Bifidobacterium longum, Lactobacillus acidophilus, Clostridium clostridioforme, Faecalibacterium prausnitzii and Akkermansia muciniphila to evaluate correlations between metals and microbial composition using biochemical, microbial, and molecular methods.

Results: Escherichia coli and Bifidobacterium longum levels in polluted areas were not significantly different from those in unpolluted areas. Bacteroides fragilis in polluted areas was significantly higher compared to non-polluted locations. Clos- tridium, Akkermansia, Faecalibacterium, and Lactobacillus acidophilus were significantly lower in polluted areas, amount- ing to less than half the levels in clean areas. Heavy metal concentrations showed no gender differences in either location.

Conclusion: Some heavy metals change intestinal microbiota composition and metabolic profiles, potentially resulting in metabolic diseases and environmental risks.