Arsenic (As) is a common metalloid which contaminates drinking water in several regions of the world and chronic exposure is associated with skin, lung, bladder, and kidney cancer. Previous studies suggest that arsenic exposure leads to a diminution of phytohemaglutinin (PHA) stimulated T cell proliferation in humans. In order to understand the mechanism of this suppression, the effect of As was evaluated on the expression of CD25, and IL-2 secretion in human peripheral blood mononuclear cells (PBMC). Inhibition of proliferation was observed in all donors studied. Most of the donors did not show any change in the expression of CD25, but IL-2 secretion was inhibited in 6 of the 7 donors tested. Proliferative inhibition was due to a suboptimal levels of IL-2 secreted by lymphocytes, since the addition of recombinant IL-2 to the cultures reversed in a dose-dependent fashion the inhibitory effect of As. The determination of the mRNA of IL-2 and the intracellular IL-2 levels demonstrated that the inhibition is not at the transcriptional level. Electron microscopy studies revealed that cellular ultrastructure in Golgi apparatus, mitochondria, cytoskeleton, and perinuclear membrane were altered. These alterations suggest that due to sodium arsenite effects on cytoskeleton, the intracellular secretion of proteins is affected, including the one of IL-2, leading to an impaired proliferation of the T cells when stimulated with PHA.

High relative abundance of firmicutes and increased TNF-α levels correlate with obesity in children

Gut microbiota is associated with the development of metabolic disorders. To study its association with childhood obesity, we performed a cross-sectional study with 46 children (6–12 years old). We collected fecal samples, food-frequency questionnaires (FFQs), and anthropometric measurements. Shotgun metagenomics were used to obtain the microbial taxonomic diversity and metabolic potential. We identified two dietary profiles characterized by complex carbohydrates and proteins (pattern 1) and saturated fat and simple carbohydrates (pattern 2). We classified each participant into normal weight (NW) or overweight and obese (OWOB) using their body mass index (BMI) z-score. The ratio of Firmicutes/Bacteroidetes and alpha diversity were not different between the BMI groups. Genera contributing to beta diversity between NW and OWOB groups included Bacteroides rodentium, B. intestinalis, B. eggerthii, Methanobrevibacter smithii, Eubacterium sp., and Roseburia sp. B. rodentium was associated with lower BMI and dietary pattern 1 intake. Eubacterium sp. and Roseburia sp. were associated with BMI increments and high consumption of dietary pattern 2. Methane and energy metabolism were found enriched in under-represented KEGG pathways of NW group compared to OWOB. Complex dietary and microbiome interaction leads to metabolic differences during childhood, which should be elucidated to prevent metabolic diseases in adolescence and adulthood.

In Mexico, 3 of 10 children are overweight. Fructose intake and relative abundance (RA) of Lactobacillus reuteri (L. reuteri) in the intestinal microbiota are associated with obesity and diabetes in adults, but studies in children are limited. This study evaluates the association between fructose intake and L. reuteri RA with adiposity and cardiometabolic risk markers in Mexican children dietary information, microbiota profiles, adiposity indicators (Body Mass Index, BMI and Waste Circumference, WC), and cardiometabolic markers were analyzed in 1087 children aged 6–12 years. Linear regression and path analysis models were used. High-tertile fructose intake and L. reuteri RA were positively associated with BMI (β_{Tertil 3 vs. Tertil 1} = 0.24 (95% CI, 0.04; 0.44) and β_{T3 vs. T1} = 0.52 (95% CI, 0.32; 0.72)) and WC (β_{T3 vs. T1} = 2.40 (95% CI, 0.93; 3.83) and β_{T3 vs. T1} = 3.40 (95% CI, 1.95; 4.90)), respectively. Also, these factors mediated by adiposity were positively correlated with high triglycerides and insulin concentrations and HOMA-IR (p ≤ 0.03) and negatively associated with HDL-C concentration (p < 0.01). High-tertile fructose intake and L. reuteri RA were directly associated with adiposity and indirectly associated though adiposity with metabolic disorders in children. In conclusion, fructose intake and L. reuteri RA were directly associated with adiposity and indirectly associated with metabolic disorders in children, mediated by adiposity.