Advanced Search Abstract The main threats to human health from heavy metals are associated with exposure to lead, cadmium, mercury and arsenic. These metals have been extensively studied and their effects on human health regularly reviewed by international bodies such as the WHO. Heavy metals have been used by humans for thousands of years.
Published online Dec This article has been cited by other articles in PMC. Abstract Background The gut microbiota is critical for intestinal homeostasis.
Recent studies have revealed the links between different types of dysbiosis and diseases inside and outside the intestine. Environmental exposure to pollutants such as heavy metals can also impair various physiological functions for good health.
Results Pyrosequencing of 16S RNA sequences revealed minor but specific changes in bacterial commensal communities at both family and genus levels following oral exposure to the heavy metals, with notably low numbers of Lachnospiraceae and high numbers levels of Lactobacillaceae and Erysipelotrichaceacae mainly due to changes in Turicibacter spprelative to control animals.
Conclusions Non-absorbed heavy metals have a direct impact on the gut microbiota. In turn, this may impact the alimentary tract and overall gut homeostasis. Our results may enable more accurate assessment of the risk of intestinal disease associated with heavy metal ingestion.
Heavy metal exposure, Gut microbiota, Mice, 16S pyrosequencing, Turicibacter, Denaturing gradient gel electrophoresis DGGE Background Chronic ingestion of environmental heavy metals HMs, such as lead Pb and cadmium Cd is associated with the occurrence of various diseases. The underlying mechanism is thought to be related to excessive local and systemic oxidative stress or deregulation of immune responses.
Intestinal absorption of HMs leads to accumulation in specific target organs, with severe detrimental effects on human health. However, high concentrations of non-absorbed HMs remain in the gut microenvironment, where they may have a direct impact on the gut ecosystem and its overall physiology [ 12 ].
The gastrointestinal epithelium has several essential functions: These processes are highly influenced by the microbiota via a complex interplay with the host [ 5 - 7 ].
Disturbance of the microbiota dysbiosis is associated with an increased risk of developing inflammatory diseases, allergic diseases and metabolic disorders; hence, it is of the utmost importance to understand microbiotal variability if we are to better understand disease states [ 89 ].
The most studied factors affecting microbiota composition are age, genetic background, diet and antibiotic consumption [ 10 ].
It has also been postulated that exposure to xenobiotic agents from the environment is an important factor shaping the gut microbiota. However, little attention has been given to the potential impact of bioavailable HMs on the commensal microbiota and intestinal homeostasis.
We thus sought to characterize possible impact of environmental Pb and Cd on the microbial ecosystem in mice, in order to better understand the potential role of environmental factors in the etiology and pathogenesis of gastrointestinal disorders in humans.
The animal work was also compliant with French legislation the French Act 87—, dated and the European Communities Amendment of Cruelty to Animals Act Control animals received water with no added CdCl2 or PbCl2.
Fecal pellets and cecal content were collected in tubes and weighed. The reverse primer contained the sequence of Titanium B adaptor primer B: Following quantitation, cleaned amplicons were combined in equimolar ratios in a single tube.
The sequences were then checked for the following criteria [ 14 ]: Each pyrosequenced dataset that passed quality control was assigned to a family with the RDP classifier version 2. The Chao richness estimate was calculated with the Mothur software package for more details, see http: The PCR and temperature program have been described elsewhere [ 17 ].
Every fifth or sixth lane contains a reference sample containing the VS rRNA amplicons of a taxonomically well-characterized strain for each of 12 bacterial species and fingerprint profiles were normalized using BioNumerics software version 5.
Statistics and data analysis All statistical analyses were performed by comparing experimental groups with the control group. In an earlier study, these HM levels were sub-toxic and not associated with hepatotoxicity or changes in behavior, organ weights liver, spleen and kidneysbody weight or overall growth when compared with regular water-treated mice, [ 11 ].
Indeed, this was demonstrated by providing oral exogenous food-grade microorganisms such as yeasts and lactic bacteria as feces markers. All the animals exhibited similar transit times and persistence parameters data not shown.
This finding contrasts with a recent report in which oral Cd had harmful effects on the viability of some components of the mouse microbiota [ 18 ]. This disparity might be explained by the fact that Fazeli and coworkers used restrictive conventional culture methods, whereas we used a molecular approach.In nuclear science, nuclei of heavy metals such as chromium, iron, or zinc are sometimes fired at other heavy metal targets to produce superheavy elements; heavy metals are also employed as spallation targets for the production of neutrons or radioisotopes such as astatine (using lead, bismuth, thorium, or uranium in the latter case).
Below is a summary of the most common heavy metals, their sources and the burden they add to the human body as provided by Doctor’s Data caninariojana.com’s Data Inc (DDI) is a premier clinical laboratory with over 30 years experience that specializes in essential and toxic elemental testing.
Cadmium, being ranked the seventh most toxic heavy metal by the Agency for Toxic Substances and Disease Registry (ATSDR), is detected in steel production, cement production, battery manufacture.
Although heavy metal toxicity is well-documented, managing its exposure and related risks is a challenge around the world (World Health Organization, ). Depending on the context, the criteria used to define heavy metals can vary, but the term generally refers to metallic chemical elements with relatively high densities and toxic properties (Singh, Gautam, Mishra, & Gupta, ).
The most toxic metals to humans and animals are mercury, cadmium and lead, known as heavy metals, all of which naturally occur in the environment.
Mercury, cadmium and lead enter the marine environment from a number of natural, agricultural and industrial processes, such as emissions from coal-fired power stations, via long range transportation.
Category Overview. Despite the natural occurrence of heavy metals, human activities are the main driver of heavy metal pollution. Even trace amounts can harm human health and the environment (Tchounwou, Yedjou, Patlolla, & Sutton, ).