139
reduced upon the exposure of As, while no change was reported in Bacteroides
levels [33]. In animal studies, As exposure induced a remarkable change in the gut
microbiome and also induced alteration in the microbial metabolites. In addition to
this, the composition of microbiome and metabolomic profiles in mice significantly
changes when they are exposed to 10 mg/L of arsenic for 4 weeks [33]. Generally,
the level of Bacteroidetes increases significantly but the level of Firmicutes decreases
due to exposure of As. Lu et al. [33] had also found that these alterations were
closely associated with the metabolites of bile acid, isoflavone, lipid, and indolecontaining metabolites. Likewise, when chronic exposure to arsenic occurs in male
mice hosts, it induced compositional and structural changes in the microbiome
which is present in the colon and also promoted amino acid and nitrogen metabolism. A variety of metabolites including bile acid intermediates, isoflavones, indoles,
fatty acids, glucuronides, and carnitines were significantly changed in As-exposed
animal model (Table 9.1). These perturbations in metabolites reflected that capability of biotransformation in the gut microbiota also changes due to arsenic exposure
[33]. The changed metabolic profile associates with altered structure of microbial
community and associated metabolomics alterations are also known to affect lipogenesis, gluconeogenesis, inflammation, and adipogenesis in the male mice
host [33].
Another heavy metal that was found to increase triacylglycerol level in liver,
triglyceride level, and serum free fatty acids is cadmium (Cd). These changes occur
upon the exposure to Cd is accompanied by a perturbation of gut microbiota
(decreased Proteobacteria and Firmicutes) in animal studies. These microbial alterations led to increase the hepatic inflammation and also increase the level of LPS in
serum that may further responsible for changes in energy homeostasis (Table 9.1) [34].
In male offspring, not in female offspring, lead (Pb) exposed during gestation
and lactation through maternal drinking water gives rise to an increased adult bodyweight. An inverse shift in Bacteroidetes and Firmicutes ratio upon the exposure of
Pb will occur and it is demonstrated through analysis that has been done on the gut
microbiota of offspring without any sex bias. According to several studies it was
found that the environmental chemicals have a role in shaping the adult gut microbiota when exposure to these chemicals occurs during pregnancy and also have their
effect on the physiology of body (Table 9.1) [36].
Persistent Organic Pollutant (POPs)
POPs consist of dioxins, polychlorinated dibenzofurans, organochlorines, and polychlorinated biphenyls. There is a positive link between diabetes and POPs exposure
which is supported by the meta-analysis of 72 various epidemiological studies [20,
39]. In animal studies, exposure of polychlorinated biphenyls (PCBs) induced significant alterations in gut microbiota with reduction in the abundance of
Proteobacteria. It is very interesting to find that PCB-induced alterations in gut
microbiota appeared to reverse by doing exercise training [40]. Exposure of
9 Alteration of Gut Microbiota in EDCs-Induced Metabolic Disorders
reduced upon the exposure of As, while no change was reported in Bacteroides
levels [33]. In animal studies, As exposure induced a remarkable change in the gut
microbiome and also induced alteration in the microbial metabolites. In addition to
this, the composition of microbiome and metabolomic profiles in mice significantly
changes when they are exposed to 10 mg/L of arsenic for 4 weeks [33]. Generally,
the level of Bacteroidetes increases significantly but the level of Firmicutes decreases
due to exposure of As. Lu et al. [33] had also found that these alterations were
closely associated with the metabolites of bile acid, isoflavone, lipid, and indolecontaining metabolites. Likewise, when chronic exposure to arsenic occurs in male
mice hosts, it induced compositional and structural changes in the microbiome
which is present in the colon and also promoted amino acid and nitrogen metabolism. A variety of metabolites including bile acid intermediates, isoflavones, indoles,
fatty acids, glucuronides, and carnitines were significantly changed in As-exposed
animal model (Table 9.1). These perturbations in metabolites reflected that capability of biotransformation in the gut microbiota also changes due to arsenic exposure
[33]. The changed metabolic profile associates with altered structure of microbial
community and associated metabolomics alterations are also known to affect lipogenesis, gluconeogenesis, inflammation, and adipogenesis in the male mice
host [33].
Another heavy metal that was found to increase triacylglycerol level in liver,
triglyceride level, and serum free fatty acids is cadmium (Cd). These changes occur
upon the exposure to Cd is accompanied by a perturbation of gut microbiota
(decreased Proteobacteria and Firmicutes) in animal studies. These microbial alterations led to increase the hepatic inflammation and also increase the level of LPS in
serum that may further responsible for changes in energy homeostasis (Table 9.1) [34].
In male offspring, not in female offspring, lead (Pb) exposed during gestation
and lactation through maternal drinking water gives rise to an increased adult bodyweight. An inverse shift in Bacteroidetes and Firmicutes ratio upon the exposure of
Pb will occur and it is demonstrated through analysis that has been done on the gut
microbiota of offspring without any sex bias. According to several studies it was
found that the environmental chemicals have a role in shaping the adult gut microbiota when exposure to these chemicals occurs during pregnancy and also have their
effect on the physiology of body (Table 9.1) [36].
Persistent Organic Pollutant (POPs)
POPs consist of dioxins, polychlorinated dibenzofurans, organochlorines, and polychlorinated biphenyls. There is a positive link between diabetes and POPs exposure
which is supported by the meta-analysis of 72 various epidemiological studies [20,
39]. In animal studies, exposure of polychlorinated biphenyls (PCBs) induced significant alterations in gut microbiota with reduction in the abundance of
Proteobacteria. It is very interesting to find that PCB-induced alterations in gut
microbiota appeared to reverse by doing exercise training [40]. Exposure of
9 Alteration of Gut Microbiota in EDCs-Induced Metabolic Disorders