Maternal serum concentrations of one-carbon metabolism factors modify the association between biomarkers of arsenic methylation efficiency and birth weight.

Background: Inorganic arsenic (iAs) is a ubiquitous metalloid and drinking water contaminant. Prenatal exposure is associated with birth outcomes across multiple studies. During metabolism, iAs is sequentially methylated to mono- and di-methylated arsenical species (MMAs and DMAs) to facilitate whole body clearance.

Effects of ALAD genotype on the relationship between lead exposure and anthropometry in a Cohort of Mexican children.

Objectives: Lead exposure is associated with children's growth, but this relationship may depend on the presence of susceptibility factors, including genetic variation. Blood lead levels (BLL) differ by ALAD (aminolevulinic acid dehydratase) genotype. We investigated the association between BLL and growth in Mexican first-graders with different ALAD genotypes.

One-carbon metabolism nutrient intake and the association between body mass index and urinary arsenic metabolites in adults in the Chihuahua cohort.

Background: Exposure to inorganic arsenic (iAs) via drinking water is a serious global health threat. Various factors influence susceptibility to iAs-associated health outcomes, including differences in iAs metabolism. Previous studies have shown that obesity is associated with iAs metabolism.

Effects of Leaves Extract on High Glucose-Induced Metabolic Changes in HepG2 Cells.

Mitochondrial dysfunction is a hallmark of diabetes, but the metabolic alterations during early stages of the disease remain unknown. The ability of liver cells to rearrange their metabolism plays an important role in compensating the energy shortage and may provide cell survival. leaves have been studied for its health properties against diabetes, insulin resistance, and non-alcoholic liver disease.

Sex differences in the reduction of arsenic methylation capacity as a function of urinary total and inorganic arsenic in Mexican children.

Chronic arsenic (As) exposure decreases adult and children's ability to methylate inorganic As (iAs); however, few studies have examined children's sex differences. We measured urinary concentrations of iAs, monomethylarsonic (MMA), and dimethylarsinic (DMA) acids, and calculated the primary (PMI: MMA/iAs) and secondary (SMI: DMA/MMA) methylation capacity indexes in 591 children 6-8 years in Torreón, Mexico. We determined iAs, MMA, and DMA by hydride generation cryotrapping AAS.

Association Between Variants in Arsenic (+3 Oxidation State) Methyltranserase (AS3MT) and Urinary Metabolites of Inorganic Arsenic: Role of Exposure Level.

Variants in AS3MT, the gene encoding arsenic (+3 oxidation state) methyltranserase, have been shown to influence patterns of inorganic arsenic (iAs) metabolism. Several studies have suggested that capacity to metabolize iAs may vary depending on levels of iAs exposure. However, it is not known whether the influence of variants in AS3MT on iAs metabolism also vary by level of exposure.

Analysis of maternal polymorphisms in arsenic (+3 oxidation state)-methyltransferase AS3MT and fetal sex in relation to arsenic metabolism and infant birth outcomes: Implications for risk analysis.

Arsenic (+3 oxidation state) methyltransferase (AS3MT) is the key enzyme in the metabolism of inorganic arsenic (iAs). Polymorphisms of AS3MT influence adverse health effects in adults, but little is known about their role in iAs metabolism in pregnant women and infants. The relationships between seven single nucleotide polymorphisms (SNPs) in AS3MT and urinary concentrations of iAs and its methylated metabolites were assessed in mother-infant pairs of the Biomarkers of Exposure to ARsenic (BEAR) cohort.

Chronic Exposure to Arsenic and Markers of Cardiometabolic Risk: A Cross-Sectional Study in Chihuahua, Mexico.

Background: Exposure to arsenic (As) concentrations in drinking water > 150 μg/L has been associated with risk of diabetes and cardiovascular disease, but little is known about the effects of lower exposures.

Objective: This study aimed to examine whether moderate As exposure, or indicators of individual As metabolism at these levels of exposure, are associated with cardiometabolic risk.

Methods: We analyzed cross-sectional associations between arsenic exposure and multiple markers of cardiometabolic risk using drinking-water As measurements and urinary As species data obtained from 1,160 adults in Chihuahua, Mexico, who were recruited in 2008-2013.

Identification of novel gene targets and putative regulators of arsenic-associated DNA methylation in human urothelial cells and bladder cancer.

There is strong epidemiologic evidence linking chronic exposure to inorganic arsenic (iAs) to myriad adverse health effects, including cancer of the bladder. We set out to identify DNA methylation patterns associated with arsenic and its metabolites in exfoliated urothelial cells (EUCs) that originate primarily from the urinary bladder, one of the targets of arsenic-induced carcinogenesis. Genome-wide, gene-specific promoter DNA methylation levels were assessed in EUCs from 46 residents of Chihuahua, Mexico, and the relationship was examined between promoter methylation profiles and the intracellular concentrations of total arsenic and arsenic species.

Metabolomic characteristics of arsenic-associated diabetes in a prospective cohort in Chihuahua, Mexico.

Chronic exposure to inorganic arsenic (iAs) has been linked to an increased risk of diabetes, yet the specific disease phenotype and underlying mechanisms are poorly understood. In the present study we set out to identify iAs exposure-associated metabolites with altered abundance in nondiabetic and diabetic individuals in an effort to understand the relationship between exposure, metabolomic response, and disease status. A nested study design was used to profile metabolomic shifts in urine and plasma collected from 90 diabetic and 86 nondiabetic individuals matched for varying iAs concentrations in drinking water, body mass index, age, and sex.

Maternal arsenic exposure, arsenic methylation efficiency, and birth outcomes in the Biomarkers of Exposure to ARsenic (BEAR) pregnancy cohort in Mexico.

Background: Exposure to inorganic arsenic (iAs) from drinking water is a global public health problem, yet much remains unknown about the extent of exposure in susceptible populations.

Objectives: We aimed to establish the Biomarkers of Exposure to ARsenic (BEAR) prospective pregnancy cohort in Gómez Palacio, Mexico, to better understand the effects of iAs exposure on pregnant women and their children.

Methods: Two hundred pregnant women were recruited for this study.

Association of arsenic and metals with concentrations of 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D among adolescents in Torreón, Mexico.

Background: Limited data suggest that lead (Pb), cadmium (Cd), and uranium (U) may disrupt vitamin D metabolism and inhibit production of 1,25-dihydroxyvitamin D [1,25(OH)2D], the active vitamin D metabolite, from 25-hydroxyvitamin D [25(OH)D] in the kidney.

Objectives: We evaluated the association between blood lead (BPb) and urine arsenic (As), Cd, molybdenum (Mo), thallium (Tl), and U with markers of vitamin D metabolism [25(OH)D and 1,25(OH)2D].

Methods: We conducted a cross-sectional study of 512 adolescents in Torreón, a town in Mexico with a Pb smelter near residential areas.

Associations between arsenic species in exfoliated urothelial cells and prevalence of diabetes among residents of Chihuahua, Mexico.

Background: A growing number of studies link chronic exposure to inorganic arsenic (iAs) with the risk of diabetes. Many of these studies assessed iAs exposure by measuring arsenic (As) species in urine. However, this approach has been criticized because of uncertainties associated with renal function and urine dilution in diabetic individuals.

Spatial clustering of toxic trace elements in adolescents around the Torreón, Mexico lead-zinc smelter.

High blood lead (BPb) levels in children and elevated soil and dust arsenic, cadmium, and lead were previously found in Torreón, northern Mexico, host to the world's fourth largest lead-zinc metal smelter. The objectives of this study were to determine spatial distributions of adolescents with higher BPb and creatinine-corrected urine total arsenic, cadmium, molybdenum, thallium, and uranium around the smelter. Cross-sectional study of 512 male and female subjects 12-15 years of age was conducted.

Environmental exposure to arsenic, AS3MT polymorphism and prevalence of diabetes in Mexico.

Exposure to arsenic in drinking water is associated with increased prevalence of diabetes. We previously reported an association of diabetes and urinary concentration of dimethylarsinite (DMAs(III)), a toxic product of arsenic methylation by arsenic (+3 oxidation state) methyltransferase (AS3MT). Here we examine associations between AS3MT polymorphism, arsenic metabolism and diabetes.

Exposure to arsenic in drinking water is associated with increased prevalence of diabetes: a cross-sectional study in the Zimapán and Lagunera regions in Mexico.

Background: Human exposures to inorganic arsenic (iAs) have been linked to an increased risk of diabetes mellitus. Recent laboratory studies showed that methylated trivalent metabolites of iAs may play key roles in the diabetogenic effects of iAs. Our study examined associations between chronic exposure to iAs in drinking water, metabolism of iAs, and prevalence of diabetes in arsenicosis-endemic areas of Mexico.

Follow-up study on lead exposure in children living in a smelter community in northern Mexico.

Background: To study the changes of children lead exposure in the city of Torreon during the last five years, after environmental and public health interventions, using the timeline of lead in blood concentration as the biomarker of exposure and its relation to lead in soil concentrations.

Methods: This follow-up study started in 2001 and consisted of 232 children living in nine neighborhoods in Torreon. Children were tested at 0, 6, 12 and 60 months.

Association of AS3MT polymorphisms and the risk of premalignant arsenic skin lesions.

Exposure to naturally occurring inorganic arsenic (iAs), primarily from contaminated drinking water, is considered one of the top environmental health threats worldwide. Arsenic (+3 oxidation state) methyltransferase (AS3MT) is the key enzyme in the biotransformation pathway of iAs. AS3MT catalyzes the transfer of a methyl group from S-adenosyl-L-methionine to trivalent arsenicals, resulting in the production of methylated (MAs) and dimethylated arsenicals (DMAs).

Speciation of arsenic in exfoliated urinary bladder epithelial cells from individuals exposed to arsenic in drinking water.

Background: The concentration of arsenic in urine has been used as a marker of exposure to inorganic As (iAs). Relative proportions of urinary metabolites of iAs have been identified as potential biomarkers of susceptibility to iAs toxicity. However, the adverse effects of iAs exposure are ultimately determined by the concentrations of iAs metabolites in target tissues.

Chronic arsenic exposure increases TGFalpha concentration in bladder urothelial cells of Mexican populations environmentally exposed to inorganic arsenic.

Inorganic arsenic (iAs) is a well-established carcinogen and human exposure has been associated with a variety of cancers including those of skin, lung, and bladder. High expression of transforming growth factor alpha (TGF-alpha) has associated with local relapses in early stages of urinary bladder cancer. iAs exposures are at least in part determined by the rate of formation and composition of iAs metabolites (MAs(III), MAs(V), DMAs(III), DMAs(V)).

Urinary trivalent methylated arsenic species in a population chronically exposed to inorganic arsenic.

Chronic exposure to inorganic arsenic (iAs) has been associated with increased risk of various forms of cancer and of noncancerous diseases. Metabolic conversions of iAs that yield highly toxic and genotoxic methylarsonite (MAsIII) and dimethylarsinite (DMAsIII) may play a significant role in determining the extent and character of toxic and cancer-promoting effects of iAs exposure. In this study we examined the relationship between urinary profiles of MAsIII and DMAsIII and skin lesion markers of iAs toxicity in individuals exposed to iAs in drinking water.

Arsenic exposure and human papillomavirus response in non-melanoma skin cancer Mexican patients: a pilot study.

We assessed the relationships between chronic arsenic (As) exposure, human papilloma virus (HPV) contact and non-melanoma skin cancer (NMSC) by means of a dermatology clinic-based case-control study (42 cases and 48 controls) in Region Lagunera, Mexico, where chronic As poisoning is endemic. Exposure was determined through detailed history of residence in the As-contaminated area and measurement of As levels in drinking water and urine. We used a consensus epitope from the central region of L1 protein of the HPV family to determine antibodies against HPV.

Polymorphisms in the human monomethylarsonic acid (MMA V) reductase/hGSTO1 gene and changes in urinary arsenic profiles.

Large interindividual variability in urinary arsenic profiles, following chronic inorganic arsenic exposure, is well-known in humans. To understand this variability, we studied the relationship between polymorphisms in the gene for human monomethylarsonic acid (MMA(V)) reductase/hGSTO1 and the urinary arsenic profiles of individuals chronically exposed to arsenic in their drinking water. To ensure that we did not overlook rare polymorphisms, not included in the public databases, we amplified and sequenced all six exons of the gene and their flanking regions, using DNA isolated from peripheral blood samples of 75 subjects, living in the vicinity of Torreon, Mexico.