Salivary N1-Methyl-2-Pyridone-5-Carboxamide, a Biomarker for Uranium Uptake, in Kuwaiti Children Exhibiting Exceptional Weight Gain

Gut microbiome and metabolomic profiles reveal the antiatherosclerotic effect of indole-3-carbinol in high-choline-fed ApoE-/- mice

BACKGROUND

The metabolites produced from choline contribute to atherosclerosis (AS) pathogenesis, and the gut microbiota is redundantly essential for this process. Indole-3-carbinol (I3C), found in cruciferous vegetables such as broccoli, cabbage, cauliflower and brussels sprouts, helps prevent hyperlipidemia, maintain the gut microbiota balance, and decrease the production of trimethylamine-N-oxide (TMAO) from choline in the diet.

PURPOSE

The objective of this research was to investigate the impact of I3C on choline-induced AS and to further elucidate the underlying mechanism involved.

METHODS

AS models of high-choline-induced ApoE-/- mice and TMAO-promoted foamy macrophages were established to observe the effect of I3C on the formation of atherosclerotic plaques and foam cells and changes in AS-related indicators (including blood biochemical indicators, TMA, TMAO, SRA, and SRB1), and integrated analyses of the microbiome and metabolome were used to reveal the mechanism of action of I3C.

RESULTS

We found that I3C inhibited high-choline-induced atheroma formation (50-100 mg/kg/d, in vivo) and slightly improved the lipid profile (15 mg/kg/d, in vivo). Moreover, I3C suppressed lipid influx at a concentration of 40 µmol/L in vitro, enhanced the diversity of the gut microbiota and the abundance of the phylum Verrucomicrobia, and consequently modified the gut microbial metabolites at a dosage of 50 mg/kg/d in the mice. Associative analyses based on microbiome and metabolomics revealed that 1-methyladenosine was a key modulator of the protective effect of I3C against AS in high-choline-induced ApoE-/- mice.

CONCLUSION

These findings demonstrate for the first time that I3C ameliorates AS progression through remodeling of the gut microbiome and metabolomics, which paves the way for the possible therapeutic use of this vegetable-derived natural compound and may reduce the clinical severity of AS-related cardiovascular diseases.

Use of omics analysis for low-dose radiotoxicology and health risk assessment: the case of uranium

Exposure to environmental pollution and the increase in the incidence of multifactorial diseases in the population have become health problems for industrialized countries. In this context, the question of the health impact of exposure to these pollutants is not clearly identified in the low-dose range. This article looks at this problem using the example of preclinical studies of the effects of chronic low-dose exposure to uranium in rats. These studies demonstrate the value of molecular screening analyses (omics) and multimodal integrative approaches, of which the extreme sensitivity and breadth of observation spectrum make it possible to observe all the biological processes affected and the mechanisms of action triggered at the molecular level by exposure to low doses. They also show the value of these analytical approaches for finding diagnostic biomarkers or indicators of prognosis, which can be necessary to evaluate a risk. Finally, the results of these studies raise the question of the health risk caused by epigenomic deregulations occurring during critical developmental phases and their potential contribution to the development of chronic diseases that are metabolic in origin or to the development of certain cancer liable in the long term to affect the exposed adult and possibly its progeny.

Multigenerational Exposure to Uranium Changes Sperm Metabolome in Rats

Male infertility is a major public health issue that can be induced by a host of lifestyle risk factors such as environment, nutrition, smoking, stress, and endocrine disruptors. Regarding the human population exposed to uranium, it is necessary to explore these effects on male reproduction in multigenerational studies. The sensitivity of mass spectrometry (MS)-based methods has already proved to be extremely useful in metabolite identification in rats exposed to low doses of uranium, but also in human sperm. We applied this method to rat sperm over three generations (F0, F1 and F2) with multigenerational uranium exposure. Our results show a significant content of uranium in generation F0, and a reduction in the pregnancy rate only in generation F1. Based on principal component analysis (PCA), we observed discriminant profiles between generations. The partial least squares discriminant analysis (PLS-DA) of the 48 annotated variables confirmed that parental exposure of generation F0 (during both the preconceptional and prenatal periods) can have metabolic effects on spermatozoa for the next two generations. Metabolomics applied to epididymal spermatozoa is a novel approach to detecting the multigenerational effects of uranium in an experimental model, but could be also recommended to identify potential biomarkers evaluating the impact of uranium on sperm in exposed infertile men.

Early Metabolomic Markers of Acute Low-Dose Exposure to Uranium in Rats

Changes in metabolomics over time were studied in rats to identify early biomarkers and highlight the main metabolic pathways that are significantly altered in the period immediately following acute low-dose uranium exposure. A dose response relationship study was established from urine and plasma samples collected periodically over 9 months after the exposure of young adult male rats to uranyl nitrate. LC-MS and biostatistical analysis were used to identify early discriminant metabolites. As expected, low doses of uranium lead to time-based non-toxic biological effects, which can be used to identify early and delayed markers of exposure in both urine and plasma samples. A combination of surrogate markers for uranium exposure was validated from the most discriminant early markers for making effective predictions. N-methyl-nicotinamide, kynurenic acid, serotonin, tryptophan, tryptamine, and indole acetic acid associated with the nicotinate–nicotinamide and tryptophan pathway seem to be one of the main biological targets, as shown previously for chronic contaminations and completed, among others, by betaine metabolism. This study can be considered as a proof of concept for the relevance of metabolomics in the field of low-dose internal contamination by uranium, for the development of predictive diagnostic tests usable for radiotoxicological monitoring.

The Associations between Blood and Urinary Concentrations of Metal Metabolites, Obesity, Hypertension, Type 2 Diabetes, and Dyslipidemia among US Adults: NHANES 1999-2016

Background

Heavy metals are well known to be associated with cancer outcomes, but its association with obesity and cardiometabolic risk outcomes requires further study.

Methods

Adult data from the National Health and Examination Survey (NHANES Continuous 1999-2016, n = 12,636 to 32,012) with data for blood or urinary metals concentrations and body mass index were used. The study aim was twofold: (1) to determine the association between heavy metals and obesity and (2) to examine the influence of heavy metals on the relationship between obesity and hypertension, type 2 diabetes, and dyslipidemia. Logistic regression was used to examine the main effects and interaction effects of metals and obesity for the odds of prevalent hypertension, type 2 diabetes, and dyslipidemia. Models were adjusted for age, gender, ethnicity, smoking status, physical active status, and poverty-income ratio, with additional adjustment for creatinine in models with the urinary measures of heavy metals. High-low concentration categories were defined by grouping metal quintiles with the most similar associations with obesity.

Results

Blood lead had a negative linear association with obesity (odds ratio (OR)  = 0.42, 95% confidence interval (CI) = 0.37-0.47). In those with obesity, high blood lead was associated with lower risk of prevalent dyslipidemia, while no association was found in those without obesity. The study observed a curvilinear relationship between urinary antimony and obesity with the moderate group having the highest odds of obesity (OR = 1.36, 1.16-1.59). However, the relationship between urinary antimony and prevalent hypertension and dyslipidemia risk was linear, positive, and independent of obesity. While not associated with prevalent obesity risk, high urinary uranium was associated with 30% (P=0.01) higher odds for prevalent type 2 diabetes.

Conclusions

The impact of environmental factors on obesity and health may be complex, and this study reinforces the heterogeneous relationship between various metals, obesity, and obesity-related metabolic diseases even at levels observed in the general population.

Emerging health risks and underlying toxicological mechanisms of uranium contamination: Lessons from the past two decades

Uranium contamination is a global health concern. Regarding natural or anthropogenic uranium contamination, the major sources of concern are groundwater, mining, phosphate fertilizers, nuclear facilities, and military activities. Many epidemiological and laboratory studies have demonstrated that environmental and occupational uranium exposure can induce multifarious health problems. Uranium exposure may cause health risks because of its chemotoxicity and radiotoxicity in natural or anthropogenic scenarios: the former is generally thought to play a more significant role with regard to the natural uranium exposure, and the latter is more relevant to enriched uranium exposure. The understanding of the health risks and underlying toxicological mechanisms of uranium remains at a preliminary stage, and many controversial findings require further research. In order to present state-of-the-art status in this field, this review will primarily focus on the chemotoxicity of uranium, rather than its radiotoxicity, as well as the involved toxicological mechanisms. First, the natural or anthropogenic uranium contamination scenarios will be briefly summarized. Second, the health risks upon natural uranium exposure, for example, nephrotoxicity, bone toxicity, reproductive toxicity, hepatotoxicity, neurotoxicity, and pulmonary toxicity, will be discussed based on the reported epidemiological cases and laboratory studies. Third, the recent advances regarding the toxicological mechanisms of uranium-induced chemotoxicity will be highlighted, including oxidative stress, genetic damage, protein impairment, inflammation, and metabolic disorder. Finally, the gaps and challenges in the knowledge of uranium-induced chemotoxicity and underlying mechanisms will be discussed.