Plasma selenium influences arsenic methylation capacity and developmental delays in preschool children in Taiwan.

Inefficient arsenic methylation capacity has been associated with developmental delay in preschool children. Selenium has antioxidant and anti-inflammatory properties that protect experimental animals from chemically induced neurotoxicity. The present study was designed to explore whether plasma selenium levels affects arsenic methylation capacity related to developmental delay in preschool children. A case-control study was conducted from August 2010 to March 2014. All participants were recruited from the Shin Kong Wu Ho-Su Memorial Teaching Hospital. In total, 178 children with a developmental delay and 88 children without a delay were recruited. High-performance liquid chromatography-linked hydride generator and atomic absorption spectrometry were used to determine urinary arsenic species, including arsenite (AsIII), arsenate (AsV), monomethylarsonic acid (MMAV), and dimethylarsinic acid (DMAV). Plasma selenium levels were measured by inductively coupled plasma mass spectrometry. As results, plasma selenium concentration was significantly inversely associated with the odds ratio (OR) of developmental delay. Plasma selenium concentration was positively associated with arsenic methylation capacity [percentage of inorganic arsenic and percentage of MMAV (MMAV%) decreased, and percentage of DMAV (DMAV%) increased]. High plasma selenium concentration and high DMA% significantly and additively interacted to decrease the OR of developmental delay; the OR and 95% confidence interval were 0.40 (0.18-0.90). This is the first study to show a combined dose-response effect of plasma selenium concentration and that efficient arsenic methylation capacity decreased the OR of developmental delay in preschool children.

Association of plasma folate, vitamin B12 levels, and arsenic methylation capacity with developmental delay in preschool children in Taiwan.

Developmental delay has been associated with inefficient arsenic methylation capacity in preschool children. Folate and vitamin B12 are important nutrients that produce s-adenosylmethionine during single-carbon metabolism and provide methyl groups for arsenic methylation. The aim of the present study was to explore whether plasma folate and vitamin B12 levels influence arsenic methylation capacity and in turn are related to developmental delay in preschool children. A case-control study was conducted in 178 children with developmental delay and 88 normal children, who were recruited from Shin Kong Wu Ho-Su Memorial Teaching Hospital from August 2010 to March 2014. Arsenite (AsIII), arsenate (AsV), monomethylarsonic acid (MMAV), and dimethylarsinic acid (DMAV) in the urine was determined by high-performance liquid chromatography-linked hydride generator and atomic absorption spectrometry. Plasma folate and vitamin B12 levels were measured using a SimulTRAC-SNB radioassay. The results show that the combination of high plasma folate and high vitamin B12 levels were correlated with efficient arsenic methylation capacity (low MMAV %, low InAs %, and high DMAV %). High MMAV % significantly increased and high DMAV % and secondary methylation index decreased the odds ratio (OR) of developmental delay in a dose-dependent manner in both low plasma folate and low vitamin B12 (low/low) groups; the multivariate OR and 95% confidence interval were 5.01 (0.83-30.06), 0.21 (0.04-1.23), and 0.20 (0.03-1.20), respectively. This is the first study to show that the combination of high plasma folate and high vitamin B12 levels increases arsenic methylation capacity and indirectly decreases the OR of developmental delay in preschool children.

Adiponectin gene polymorphisms and obesity increase the susceptibility to arsenic-related renal cell carcinoma.

Our recent study found that high urinary total arsenic levels were associated with renal cell carcinoma (RCC). Recent studies demonstrated that low circulating adiponectin was related to RCC. The aim of the present study was to explore the relationship between adiponectin gene (ADIPOQ) polymorphisms and RCC and investigate whether individuals with an ADIPOQ risk genotype, obesity, and high urinary total arsenic levels have a modified odds ratio (OR) of RCC. A total of 389 RCC patients and 389 age- and sex-matched controls were recruited between November 2006 and December 2012 in Taiwan. Image-guided biopsy or surgical resection of renal tumors was performed to pathologically verify RCC. Genomic DNA was used to examine the genotypes of the ADIPOQ rs182052, ADIPOQ rs2241766, ADIPOQ rs1501299, and ADIPOQ rs1063539 SNPs by PCR-RFLP. HPLC-HG-AAS was used to measure the concentrations of urinary arsenic species. Participants with the ADIPOQ rs182052 G/A+A/A genotype had a significantly higher OR of RCC compared with those with the ADIPOQ rs182052 G/G genotype. The OR (95% confidence interval [CI]) was 1.70 (1.23-2.36). The OR of RCC for the combined effect of high urinary total arsenic levels and obesity, which was dose-dependent, in individuals with the ADIPOQ rs182052 G/A+A/A genotype was 9.33 (3.85-22.62). The present study found significant combined effects of obesity and the ADIPOQ rs182052 G/A+A/A genotype on the arsenic-related risk of RCC in a population with low arsenic exposure. Arsenic exposure, obesity, and the ADIPOQ rs182052 polymorphism could be predictors of a higher OR of RCC.

Polymorphism of nucleotide binding domain-like receptor protein 3 (NLRP3) increases susceptibility of total urinary arsenic to renal cell carcinoma.

Our study showed that total urinary arsenic concentrations were positively correlated with renal cell carcinoma (RCC). Chronic inflammation is a key player in the development of RCC. This study explored the association between nucleotide-binding domain-like receptor protein 3 (NLRP3) genotypes and the development of RCC. We also investigated whether any of the NLRP3 genotypes modified the risk between arsenic and RCC. We recruited 350 RCC patients and 700 age-sex matched controls. RCC was confirmed by pathological assessment following surgical resection or image-guided biopsy of a renal tumor. Fifteen sites of NLRP3 gene polymorphisms were identified using the Agena Bioscience MassARRAY platform. The concentrations of the urinary arsenic species were determined by HPLC-HG-AAS. There was a significant dose-dependent association between arsenic and RCC. In addition, six of thirteen NLRP3 alleles, including rs12239046 C, rs10925025 G, rs1539019 C, rs10925026 A, rs10157379 T, and rs12143966 A, had increased odds ratios (ORs) for RCC than other NLRP3 alleles. Among these sites, we found the novel haplotype of five tag-SNPs (C-A-A-A-A) was significantly related to RCC, the OR and 95% confidence interval was 1.44 (1.08-1.92). Furthermore, participants with high total urinary arsenic levels and the NLRP3 rs1539019 C allele had significantly multiplicative and additive interactions for the risk of RCC (p interaction = 0.012). This study is the first to identify the modified effects of NLRP3 risk alleles involved in the association between arsenic and RCC risk in a population with low arsenic exposure.

The association between plasma selenium and chronic kidney disease related to lead, cadmium and arsenic exposure in a Taiwanese population.

This study aimed to determine the interaction of red blood cell cadmium and lead, total urinary arsenic, and plasma selenium in chronic kidney disease (CKD). We recruited 220 CKD patients as well as 438 gender- and age-matched controls, and we defined CKD as <60 mL/min/1.73 m2 estimated glomerular filtration rate (eGFR) for three or more consecutive months. Plasma selenium and red blood cell cadmium and lead concentrations were measured by ICP-MS. Urinary arsenic species were determined via HPLC-HG-AAS and were summed to determine the total urinary arsenic concentration. Plasma selenium was positively correlated to eGFR, and subjects with high plasma selenium levels (>243.90 µg/L) had a significantly lower odds ratio (OR) and 95% confidence interval (CI) (0.23, 0.13-0.42) for CKD compared to those with low plasma selenium levels (≤ 196.70 µg/L). High plasma selenium and low red blood cell cadmium or lead concentrations interacted to decrease the OR and 95% CI for CKD (0.12, 0.06-0.26; 0.09, 0.04-0.19). High plasma selenium and low red blood cell lead levels also interacted to increase the eGFR (20.70, 15.56-26.01 mL/min/1.73 m2). This study is the first to suggest that selenium modifies the eGFR and OR in CKD induced by environmental toxicants.

Comparison of arsenic methylation capacity and polymorphisms of arsenic methylation genes between bladder cancer and upper tract urothelial carcinoma.

Arsenic exposure is an environmental risk factor for urothelial carcinoma (UC). The natural history of upper tract urothelial carcinoma (UTUC) differs from that of bladder cancer (BC). However, the risk factors of BC and UTUC are not exactly the same and should be discussed separately. The aims of this study were to evaluate 1) the association between arsenic methylation capacity and UTUC and/or BC, separately, and 2) the association between polymorphisms of the arsenic metabolism-related genes AS3MT, GSTOs, and PNP against BC and/or UTUC, separately. We conducted a hospital-based study and collected 216 BC and 212 UTUC cases, and 813 healthy controls, from September 2007 to October 2011. Urinary arsenic profiles were measured using high-performance liquid chromatography-hydride generator-atomic absorption spectrometry. The polymorphisms of AS3MT, GSTO, and PNP were identified using the Sequenom MassARRAY platform with iPLEX Gold chemistry. We found that inefficient arsenic methylation capacity was associated with BC in a significant dose-response relationship, but only found that high urinary total arsenic concentration was related to the risk of UTUC, also in a significant dose-response manner. Those with a total urinary arsenic level of > 30.28 µg/L compared to ≤ 9.78 µg/L, had a odds ratio (OR), and 95% confidence interval (CI) of UTUC, of 4.80 (2.22-10.39). The polymorphisms of AS3MT rs11191438, AS3MT rs10748835, and AS3MT rs1046778 were related to the risk of BC and UTUC, while the polymorphisms of AS3MT rs3740393, AS3MT rs11191453, and AS3MT rs11191454 were associated with arsenic methylation capacity. The AS3MT gene polymorphisms and arsenic methylation capacity appear to independently affect the risk of BC and UTUC.

Polymorphisms of Arsenic (+3 Oxidation State) Methyltransferase and Arsenic Methylation Capacity Affect the Risk of Bladder Cancer.

The mechanisms underlying how arsenic methylation capacity affects bladder cancer (BC) are still unclear. The objective of this study was to explore the effects of polymorphisms of arsenic (+3 oxidation state) methyltransferase (AS3MT) on BC risk. We conducted a hospital-based study and enrolled 216 BC and 648 healthy controls from 2007 to 2011. Urinary arsenic profiles were measured using high-performance liquid chromatography-hydride generation-atomic absorption spectrometry. The gene polymorphisms of AS3MT were identified using the Sequenom MassARRAY platform with iPLEX Gold chemistry. Inefficient arsenic methylation capacity (high monomethylarsonic acid percentage [MMA%] and low dimethylarsinic acid percentage [DMA%]) was associated with increased risk of BC in a dose-response relationship. AS3MT rs11191438 (C > G) G/G genotype, AS3MT rs10748835 (A > G) G/G genotype, and AS3MT rs1046778 (C > T) T/T genotype were found to be related to BC risk, where the odds ratio (OR) (95% CI) was 0.50 (0.31-0.82), 0.49 (0.30-0.79), and 0.54 (0.36-0.80), respectively. The combination of AS3MT haplotype 2 (AS3MT rs11191453, rs11191454, rs10748835, and rs1046778)'s high-risk haplotype (C-G-A-C, T-A-A-C, and T-G-G-T) was significantly associated with increased risk of BC. Among controls, only 3 of the 9 candidate genotypes evaluated, rs1119438 C/C, rs10748835 A/A and rs1046778 C/C, were associated with significantly higher MMA% compared with the other genotypes. No other genotypes or haplotypes were related to arsenic methylation capacity. High MMA%, low DMA% and AS3MT rs1046778 C/C + C/T genotype predicted a significantly higher risk of BC according to stepwise multiple logistic regression analyses. AS3MT gene polymorphisms and arsenic methylation capacity appeared to affect BC risk independently.