Chronic Arsenic Exposure and Oxidative Stress:
            <i>OGG1</i>
            Expression and Arsenic Exposure, Nail Selenium, and Skin Hyperkeratosis in Inner Mongolia

Chronic exposure to arsenic (As) threatens human health. To systematically understand the health risks induced by As ingestion, we explored water and diet contributions to As exposure, and compared As in biomarkers and the arsenicosis in a geogenic As area in China. In this study, high percentages of water (77% of n = 131 total samples), vegetables (92%, n = 120), cereals (32%, n = 25), urine (70%, n = 99), nails (76%, n = 176), and hair (62%, n = 61) contained As higher than the acceptable levels. Dietary As contributed 92% of the average daily dose (ADD) when the water As concentration was less than 10 μg/L, for which 5 out of 30 examined participants were diagnosed with arsenicosis symptoms. The distinct positive correlation between ADD and As concentrations in urine, nails, and hair suggests different applicability for these biomarkers. Methylated As as the predominant urinary As species confirms that the ingested inorganic As is methylated and is excreted through urine. In situ microdistribution and speciation analysis indicates that As is mainly associated with sulfur in nails and hair. Nails, rather than hair and urine, could be used as a proper biomarker for arsenicosis. High ADD from the environment and low excretion could result in As toxicity to humans. ■ INTRODUCTIONArsenic (As) poses a severe threat to human health through exposure pathways mainly including water and diet. 1,2 Drinking water with elevated As levels is the primary source of As ingestion. 1,3 Moreover, As-laden groundwater, if used for irrigation, can lead to appreciable amounts of As accumulation in vegetables and cereals. 4−6 Extensive research demonstrates that rice and rice products could be another As source. 7,8 However, not much attention has been paid to other cereals like wheat, which are important staple foods worldwide, that could lead to significant As ingestion. 9 The intake of As results in its detection in noninvasive human biomarkers such as urine, nails, and hair. 10−12 Urine has frequently been used as a biomarker for short-term exposure because most As metabolites are excreted within 3−4 days through urine. 12,13 Nails and hair indicate long-term exposure for 2−12 months, 10 as As can be accumulated in these structures rich in keratin. 14 Thus, the association of As levels in biomarkers and groundwater has been recently studied to evaluate its health risks. 11,15 The speciation of As in biomarkers is crucial to understand the transformation, metabolism, and toxicity of ingested As. 12,16 As species in hair and nails are traditionally determined by chemical extraction, where inorganic and methylated As are detected. 14,17 No As−S species have been reported using indirect chemical extraction methods, even though As readily bonds to sulphydryl groups. 14 In contrast, As−S species have been detected in nail and hair samples using in situ X-ray absorption near-edge structure (XANES) spectroscopy. 15 Unfortunately, methylated As species are not distinguished from the As−S form in nails, 18 which deserves further...

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“…This observation was in agreement with previous reports. 3,35 This extremely high rate can be attributed to the As intake from diet.…”

Section: ■ Materials and Methodsmentioning

confidence: 99%

Arsenic Levels and Speciation from Ingestion Exposures to Biomarkers in Shanxi, China: Implications for Human Health

Cui

Shi

Jiang

et al. 2013

Environ. Sci. Technol.

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“…A study in Inner Mongolia suggested that arsenic induced gene expression of 8-oxoguanine glycosylase 1 (ogg1) may contribute to elevated excretion of 8-OHdG in urine. EFSA Journal 2009; 7(10):1351 Therefore ogg1 expression levels were linked to arsenic concentrations in drinking water (0.34-826 μg arsenic/L) and nails, selenium concentrations in nails, and skin hyperkeratosis (Mo et al, 2006). Elevated tissue 8-OHdG levels were reported for arsenic-related skin neoplasms and keratosis of arsenic-related Bowen's diseases (Matsui et al, 1999) and arsenic-related human skin tumours of inhabitants in an arsenic contaminated area in China .…”

Section: Effects In Humansmentioning

confidence: 99%

Scientific Opinion on Arsenic in Food

2009

EFSA Journal

823

199

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The EFSA Panel on Contaminants in the Food Chain (CONTAM Panel) assessed the risks to human health related to the presence of arsenic in food. More than 100,000 occurrence data on arsenic in food were considered with approximately 98 % reported as total arsenic. Making a number of assumptions for the contribution of inorganic arsenic to total arsenic, the inorganic arsenic exposure from food and water across 19 European countries, using lower bound and upper bound concentrations, has been estimated to range from 0.13 to 0.56 µg/kg bodyweight (b.w.) per day for average consumers, and from 0.37 to 1.22 µg/kg b.w. per day for 95 th percentile consumers. Dietary exposure to inorganic arsenic for children under three years of age is in general estimated to be from 2 to 3-fold that of adults. The CONTAM Panel concluded that the provisional tolerable weekly intake (PTWI) of 15 µg/kg b.w. established by the Joint FAO/WHO Expert Committee on Food Additives (JECFA) is no longer appropriate as data had shown that inorganic arsenic causes cancer of the lung and urinary bladder in addition to skin, and that a range of adverse effects had been reported at exposures lower than those reviewed by the JECFA. The CONTAM Panel modelled the dose-response data from key for providing consumption information and calculating exposure, the partners of the EFSA project on the "Individual food consumption data and exposure" coordinated by Ghent University (Department of Public Health, University Hospital, Ghent University, Belgium), and RIKILT (Institute of Food Safety, Wageningen, The Netherlands) for the accessibility of the exposure assessment tools. 4 Table of contents shows now the fourth level of subheadings. 5 An error in the interpretation of the total number of the population in the study of Rahman et al. (2006a) was discovered (Table 41). The BMDL was recalculated and as a consequence it was not considered a potential reference point. The text in the opinion, Table 43 and Appendix were revised accordingly. In addition, the header of the "total number of cases" was replaced by "total number of individuals" in Tables 40-42 and the erroneous units were corrected to µg/L in the text below SUMMARYArsenic is a metalloid that occurs in different inorganic and organic forms, which are found in the environment both from natural occurrence and from anthropogenic activity. The inorganic forms of arsenic are more toxic as compared to the organic arsenic but so far most of the occurrence data in food collected in the framework of official food control are still reported as total arsenic without differentiating the various arsenic species. The need for speciation data is evident because several investigations have shown that especially in seafood most of the arsenic is present in organic forms that are less toxic. Consequently, a risk assessment not taking into account the different species but considering total arsenic as being present exclusively as inorganic arsenic would lead to a considerable overestimation of the health risk rel...

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“…MDA, a reactive metabolite, produced during peroxidation of polyunsaturated fatty acid tends to bombards tissue borne molecules [29,30], resulting in a high MDA/ antioxidant enzyme ratio, oxidative stress and tissue deterioration. As far as this study is concerned, AlCl3 induced hepatotoxicity was mediated by oxidative stress.…”

Section: Discussionmentioning

confidence: 99%

Allium cepa Mitigates Aluminum Chloride-Induced Hepatotoxicity in Male Wistar Rats

Ige¹,

Adeniyi²,

Iyalla³

2017

J Biomedical Sci

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Allium cepa (Common Onion), one of the most widely grown crops in world, is believed to possess medicinal potency. The present study was designed to investigate the effect of Allium cepa (ACE) administration on oxidative stress-mediated hepatotoxicity following aluminum chloride (AlCl3) administration. 24 adult male wistar rats weighing 175 g were randomly divided into vehicle-treated (control), ACE, aluminum chloride (AlCl3) and ACE+AlCl3 groups. Rats were given single oral administrations of 100mg/kg body weight of AlCl3 and 1 mL/0.1 kg body weight of ACE for four weeks. When compared with vehicle-treated, AlCl3 administration caused a significant decrease in serum total protein (TP) and an increase in serum levels of alanine transaminase (ALT), aspartate transaminase (AST) and total bilirubin. On the other hand, ACE treatment significantly improved serum TP but depressed serum levels of ALT, AST and total bilirubin. There was no significant change in these biomarkers of liver function in ACE+AlCl3 group compared with the vehicle-treated group. Furthermore, while AlCl3 group was characterized by a significant rise in hepatic malondialdehyde (MDA) and a decrease in hepatic superoxide dismutase (SOD) and catalase activities, ACE group exhibited a significant low hepatic MDA and a high hepatic SOD and catalase activities. However, none of these antioxidant markers changed in ACE+AlCl3 group compared with vehicle-treated. Therefore, we conclude that ACE mitigates hepatotoxic effect of AlCl3 administration through regulation of hepatic oxidant/antioxidant system.

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Chronic Arsenic Exposure and Oxidative Stress: OGG1 Expression and Arsenic Exposure, Nail Selenium, and Skin Hyperkeratosis in Inner Mongolia

Cited by 90 publications

References 34 publications

Arsenic Levels and Speciation from Ingestion Exposures to Biomarkers in Shanxi, China: Implications for Human Health

Arsenic Levels and Speciation from Ingestion Exposures to Biomarkers in Shanxi, China: Implications for Human Health

Scientific Opinion on Arsenic in Food

Allium cepa Mitigates Aluminum Chloride-Induced Hepatotoxicity in Male Wistar Rats

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