Intakes of several nutrients are associated with incidence of arsenic-related keratotic skin lesions in Bangladesh

Gut microbiota and plasma metabolites in pregnant mothers and infant atopic dermatitis: A multi-omics study

Background

Many studies reported the influence of infants' gut microbiota on atopic dermatitis (AD) postnatally, yet the role of maternal gut microbiota and plasma metabolites in infants' AD remains largely unexplored.

Methods

Sixty-three pregnant mother-infants were enrolled and followed after childbirth in Guangzhou, China. Demographic information, maternal stool and plasma samples, and records for infants' AD were collected. Maternal gut microbiota/metabolome and plasma metabolome were profiled using shotgun metagenomics and non-targeted metabolomics. Logistic regression and multi-omics analysis were used to explore characteristic maternal gut microbiota in the AD and health groups.

Results

The α-diversity of maternal gut microbiota in health group was significantly higher than AD group (Shannon diversity P = 0.02, Simpson diversity P = 0.04). Short-chain fatty acids (SCFAs) producing microorganisms, including Faecalibacterium, Roseburia, Butyricicoccus, and Ruminococcus, as well as the abundance of phenylalanine, tyrosine, and tryptophan biosynthesis pathway, were enriched in health group (LDA>2 and P < 0.05). Virulent factors (VFs) involved in immune modulation were enriched in the health group, while VFs involving in adhesin were enriched in the AD group (P < 0.05). Metabolomic analysis showed that a polyunsaturated fatty acid/linoleic acid, 13S-hydroxyoctadecadienoic, were negatively associated with AD in both the gut and plasma samples (FDR<0.05). Several other linoleic acids and flavonoids were negatively associated with AD (FDR<0.05). Neural network analysis revealed that microorganisms enriched in health group may produce these protective fatty acids.

Conclusions

Our findings show that maternal gut microorganisms/metabolites and plasma metabolites during pregnancy impact subsequent pathogenesis of infants AD. This illuminates new strategies against early AD in offspring.

Influence of Dietary Compounds on Arsenic Metabolism and Toxicity. Part II-Human Studies

Exposure to various forms of arsenic (As), the source of which may be environmental as well as occupational exposure, is associated with many adverse health effects. Therefore, methods to reduce the adverse effects of As on the human body are being sought. Research in this area focuses, among other topics, on the dietary compounds that are involved in the metabolism of this element. Therefore, the aim of this review was to analyze the influence of methionine, betaine, choline, folic acid, vitamin B2, B6, B12 and zinc on the efficiency of inorganic As (iAs) metabolism and the reduction in the severity of the whole spectrum of disorders related to As exposure. In this review, which included 62 original papers (human studies) we present the current knowledge in the area. In human studies, these compounds (methionine, choline, folic acid, vitamin B2, B6, B12 and zinc) may increase iAs metabolism and reduce toxicity, whereas their deficiency may impair iAs metabolism and increase As toxicity. Taking into account the results of studies conducted in populations exposed to As, it is reasonable to carry out prophylactic activities. In particular nutritional education seems to be important and should be focused on informing people that an adequate intake of those dietary compounds potentially has a modulating effect on iAs metabolism, thus, reducing its adverse effects on the body.

Assessment of arsenic exposure in the population of Sabalpur village of Saran District of Bihar with mitigation approach

Arsenic poisoning through groundwater is the world's greatest normal groundwater catastrophe which got an immense effect on worldwide general wellbeing. India is confronting the outcomes of arsenic poisoning in the zone of Ganga Brahmaputra alluvial plains. In Bihar, out of 38 districts, 18 districts are exceptionally influenced with groundwater arsenic defilement. In the present study, we have assessed the current situation of arsenic exposure in Sabalpur village of Saran district of Bihar after reporting of breast, renal, skin and thyroid cancer cases from this village along with typical symptoms of arsenicosis. Such cancer patients were identified at our institute and were taken for the study. The present investigation deals with the quantification of arsenic in groundwater, hair and nail samples of subjects as well as the survey of entire village to know the overall health status of the village people. A total of n=128 household handpump water samples as well as n=128 human hair and nail samples were collected from over n=520 households. Using the graphite furnace atomic absorption spectrophotometer (GF-AAS), all the samples were analysed. The investigation resulted that the 61% of the analysed samples particularly the groundwater had the arsenic levels more than the permissible limit of WHO (> 10 μg/L) with 244.20 μg/L as the highest arsenic contamination in one of the handpump water sample. The exposure effect of hair sample was worst as 88% of all the collected samples were having high arsenic levels more than the permissible limit (> 0.2 mg/Kg). In case of nail samples, 92% of the samples were having high arsenic concentration more than the permissible limit (> 0.5 mg/Kg). The health survey study revealed high magnitude of disease burden in the exposed population with symptoms such as asthma, anaemia, hepatomegaly, diabetes, cardiac problem, skin fungal infections, breathlessness and mental disability. Few cancer cases of renal, skin, breast and cervix were also found among the exposed population of this village. The percentage of cancer cases in this village was 0.94% that was low, but it would be an aggravated situation in the near future if people will continue drinking arsenic-contaminated water. Therefore, a mitigation intervention was carried out in March 2020 by installing an arsenic filter plant. The health situation in the village in the present scenario is hope to improve in the coming years. However, motivation and awareness among the village population are still required.

Arsenic exposure in Indo Gangetic plains of Bihar causing increased cancer risk

Reportedly, 300 million people worldwide are affected by the consumption of arsenic contaminated groundwater. India prominently figures amongst them and the state of Bihar has shown an upsurge in cases affected by arsenic poisoning. Escalated arsenic content in blood, leaves 1 in every 100 human being highly vulnerable to being affected by the disease. Uncontrolled intake may lead to skin, kidney, liver, bladder, or lung related cancer but even indirect forms of cancer are showing up on a regular basis with abnormal arsenic levels as the probable cause. But despite the apparent relation, the etiology has not been understood clearly. Blood samples of 2000 confirmed cancer patients were collected from pathology department of our institute. For cross-sectional design, 200 blood samples of subjects free from cancer from arsenic free pockets of Patna urban agglomeration, were collected. Blood arsenic levels in carcinoma patients as compared to sarcomas, lymphomas and leukemia were found to be higher. The geospatial map correlates the blood arsenic with cancer types and the demographic area of Gangetic plains. Most of the cancer patients with high blood arsenic concentration were from the districts near the river Ganges. The raised blood arsenic concentration in the 2000 cancer patients strongly correlates the relationship of arsenic with cancer especially the carcinoma type which is more vulnerable. The average arsenic concentration in blood of the cancer patients in the Gangetic plains denotes the significant role of arsenic which is present in endemic proportions. Thus, the study significantly correlates and advocates a strong relation of the deleterious element with the disease. It also underlines the need to address the problem by deciphering the root cause of the elevated cancer incidences in the Gangetic basin of Bihar and its association with arsenic poisoning.

Vitamin B-6 Intake Is Modestly Associated with Arsenic Methylation in Uruguayan Children with Low-Level Arsenic Exposure

BACKGROUND

Detoxification of inorganic arsenic (iAs) occurs when it methylates to form monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA). Lower proportions of urinary iAs and MMA, and higher proportions of DMA indicate efficient methylation. The role of B-vitamins in iAs methylation in children with low-level arsenic exposure is understudied.

OBJECTIVES

Our study objective was to assess the association between B-vitamin intake and iAs methylation in children with low-level arsenic exposure (<50 µg/L in water; urinary arsenic 5-50 µg/L).

METHODS

We conducted a cross-sectional study in 290 ∼7-y-old children in Montevideo. Intake of thiamin, riboflavin, niacin, vitamin B-6, and vitamin B-12 was calculated by averaging 2 nonconsecutive 24-h recalls. Total urinary arsenic concentration was measured as the sum of urinary iAs, MMA, and DMA, and adjusted for urinary specific gravity; iAs methylation was measured as urinary percentage As, percentage MMA, and percentage DMA. Arsenic concentrations from household water sources were assessed. Linear regressions tested the relationships between individual energy-adjusted B-vitamins and iAs methylation.

RESULTS

Median (range) arsenic concentrations in urine and water were 9.9 (2.2-48.7) and 0.45 (0.1-18.9) µg/L, respectively. The median (range) of urinary percentage iAs, percentage MMA, and percentage DMA was 10.6% (0.0-33.8), 9.7% (2.6-24.8), and 79.1% (58.5-95.4), respectively. The median (range) intake levels of thiamin, riboflavin, niacin, and vitamin B-6 were 0.81 (0.19-2.56), 1.0 (0.30-2.24), 8.6 (3.5-23.3), and 0.67 (0.25-1.73) mg/1000 kcal, respectively, whereas those of folate and vitamin B-12 were 216 (75-466) and 1.7 (0.34-8.3) µg/1000 kcal, respectively. Vitamin B-6 intake was inversely associated with urinary percentage MMA (β = -1.60; 95% CI: -3.07, -0.15). No other statistically significant associations were observed.

CONCLUSIONS

Although vitamin B-6 intake was inversely associated with urinary percentage MMA, our findings suggest limited support for a relation between B-vitamin intake and iAs methylation in children exposed to low-level arsenic.

Arsenic Exposure, Assessment, Toxicity, Diagnosis, and Management: Guidance for Occupational and Environmental Physicians

: Arsenic is ubiquitous in the environment and human exposure can occur from multiple possible routes including diet. Occupational medicine physicians asked to evaluate workers with elevated urine arsenic levels may be unaware that many sources of arsenic exposure are not work related. In this paper, we address arsenic exposure sources and pathways, adverse health effects of arsenic exposure and those subpopulations at increased risk, and the evaluation and treatment of those exposed to elevated arsenic levels.

Nutritional management can assist a significant role in alleviation of arsenicosis

Consumption of arsenic contaminated water causes serious skin disease and cancer in a significant number of exposed people. Chelating agents, consider an expensive therapy, are employed in the treatment of arsenic intoxication. There are reports which suggest that the poorest suffer the most from arsenicosis. This may be due to improper diet intake, consist of low protein and micronutrients which increase the vulnerability to arsenic-related disorders. Several human studies demonstrated the associations between malnourishment and the development of arsenic-caused skin lesions, skin cancer and cardiovascular effects. Thus, there is an urgent need of implementation of mitigation strategies for improving the health of exposed populations. Nutrition enhances the detoxification process so food rich in vitamins, protein, antioxidants help in its detoxification process. Methylation is the detoxification process which takes place via S-adenosylmethionine (SAM). It is a methyl group donor and it derived its methyl group from diet. Nutritional intervention thus may appear as a practical and inexpensive approach. Nutrition provides protection from toxic effect of arsenic by two ways (i) methylation of As (ii) antioxidants which provides protection against free radical species. The governments and NGOs may run awareness programmes in arsenic affected area regarding prevention and alternate therapy which can decrease the susceptibility of the exposed population. They could also help in distributing cheaper, high protein diets particularly to the masses who cannot afford such foods. Thus, to prevent arsenicosis alternate therapy and proper nutrition could be the important strategy for alleviating its toxic effects. This mini review provides an insight on the importance of nutrition in preventing adverse effect cause by arsenic to suffer population.

Dietary B Vitamin Intake Is Associated with Lower Urinary Monomethyl Arsenic and Oxidative Stress Marker 15-F2t-Isoprostane among New Hampshire Adults

Background: Arsenic exposure has been associated with an increased risk of cardiovascular disease (CVD). Growing evidence suggests that B vitamins facilitate arsenic metabolism and may protect against arsenic toxicity. However, to our knowledge, few studies have evaluated this in US populations.Objective: Our objective was to examine whether higher B vitamin intake is associated with enhanced arsenic metabolism and lower concentrations of preclinical markers of CVD among New Hampshire adults.Methods: We used weighted quantile sum (WQS) regression to evaluate the collective impact of 6 dietary B vitamins (thiamin, riboflavin, folate, niacin, and vitamins B-6 and B-12) on 1) the proportion of arsenic metabolites in urine and 2) 6 CVD-related markers [including urinary 15-F_2t-isoprostane (15-F_2t-IsoP)] among 418 participants (26-75 y of age) from the New Hampshire Health Study. Contributions of arsenic metabolites to B vitamin-CVD marker associations were also explored in structural equation models.Results: In WQS models, the weighted sum of B vitamin intakes from food sources was inversely associated with the proportion of monomethyl arsenic species in urine (uMMA) (β: -1.03; 95% CI: -1.91, -0.15; P = 0.02). Thiamin and vitamins B-6 and B-12 contributed the most to this association, whereas riboflavin had a negligible effect. Higher overall B vitamin intake was also inversely associated with 15-F_2t-IsoP (β: -0.21; 95% CI: -0.32, -0.11; P < 0.01), with equal contributions from the 6 B vitamins, which was partially explained by differences in the proportion of uMMA (indirect effect β: -0.01; 95% CI: -0.04, -0.00).Conclusions: Among New Hampshire adults, higher intakes of certain B vitamins (particularly thiamin and vitamins B-6 and B-12 from food sources) may reduce the proportion of uMMA, an intermediate of arsenic metabolism that has been associated with an increased risk of CVD. Higher overall B vitamin intake may also reduce urinary 15-F_2t-IsoP, a marker of oxidative stress and potential risk factor for CVD, in part by reducing the proportion of uMMA.

Medicinal plants and natural products in amelioration of arsenic toxicity: a short review

CONTEXT

Chronic arsenic toxicity (arsenicosis) is considered a serious public health menace worldwide, as there is no specific, safe, and efficacious therapeutic management of arsenicosis.

OBJECTIVES

To collate the studies on medicinal plants and natural products with arsenic toxicity ameliorative effect, active pre-clinically and/or clinically.

METHODS

Literature survey was carried out by using Google, Scholar Google and Pub-Med. Only the scientific journal articles found on the internet for last two decades were considered. Minerals and semi-synthetic or synthetic analogs of natural products were excluded.

RESULTS

Literature study revealed that 34 medicinal plants and 14 natural products exhibited significant protection from arsenic toxicity, mostly in preclinical trials and a few in clinical studies.

CONCLUSION

This research could lead to development of a potentially useful agent in clinical management of arsenicosis in humans.

Evaluation of the quality of life in patients with arsenic keratosis

BACKGROUND

Chronic exposure to inorganic arsenic is an important public health problem and leads to hyperpigmentation, hyperkeratosis, Bowen's disease and non-melanoma skin cancers in humans. Arsenic keratosis is the most common skin change that is associated with arsenic exposure. It may be an indicator of arsenic induced health hazards.

OBJECTIVE

To determine the needs of patients with arsenic keratosis by evaluating the impact of disease on the quality of life with respect to treatment and provide rehabilitation services.

METHODS

A total of 47 subjects with arsenic hyperkeratosis, were enrolled in this crossover study. The demographics, smoking status and the presence of chronic diseases diagnosed by the physician were recorded. Weight and height of the subjects were measured and BMI was calculated. The patients were asked to respond the visual analogue scale and EuroQoL-5D scales for assessing the pain and quality of life impairment associated with arsenic hyperkeratosis.

RESULTS

In the study group, moderate to severe problems were reported in 78.7% of patients for pain/uncomfortable condition domains and in 91.5% in anxiety/depression domains. Lower quality of life was reported in those with associated chronic disorders, at an advanced age, in thin patients and in those with severe lesions.

CONCLUSION

According to our knowledge, our study is the first one measuring the quality of life in patients with arsenic keratosis in the literature. By this study, we tried to underline the guidance of health services to be developed towards the needs of patients and the need for the development of new health policies by determining the requirements of these patients.

Associations between Diet and Toenail Arsenic Concentration among Pregnant Women in Bangladesh: A Prospective Study

This prospective study evaluated the relationship between long-term dietary habits and total arsenic (As) concentration in toenail clippings in a cohort of 1616 pregnant women in the Bangladeshi administrative regions of Sirajdikhan and Pabna Sadar. Diet was assessed at Gestation Week 28 and at Postpartum Month 1, using a locally-validated dish-based semi-quantitative food-frequency questionnaire. Toenail As concentration was analyzed by microwave-assisted acid digestion and inductively coupled plasma mass spectrometry. Associations between natural log-transformed consumption of individual food items and temporally matched natural log-transformed toenail As concentration were quantified using general linear models that accounted for As concentration in the primary drinking water source and other potential confounders. The analysis was stratified by As in drinking water (≤50 μg/L versus >50 μg/L) and the time of dietary assessment (Gestation Week 28 versus Postpartum Week 1). Interestingly, toenail As was not significantly associated with consumption of plain rice as hypothesized. However, toenail As was positively associated with consumption of several vegetable, fish and meat items and was negatively associated with consumption of rice, cereal, fruits, and milk based food items. Further studies in pregnant women are needed to compare As metabolism at different levels of As exposure and the interaction between dietary composition and As absorption.

Calcium Deficiency in Bangladesh: Burden and Proposed Solutions for the First 1000 Days

BACKGROUND

Bangladesh incurs among the highest prevalence of stunting and micronutrient deficiencies in the world, despite efforts against diarrheal disease, respiratory infections, and protein-energy malnutrition which have led to substantial and continuous reductions in child mortality over the past 35 years. Although programs have generally paid more attention to other micronutrients, the local importance of calcium to health has been less recognized.

OBJECTIVE

To synthesize available information on calcium deficiency in Bangladesh in order to inform the design of an effective national calcium program.

METHODS

We searched 3 online databases and a multitude of survey reports to conduct a narrative review of calcium epidemiology in Bangladesh, including population intake, determinants and consequences of deficiency, and tested interventions, with particular reference to young children and women of childbearing age. This was supplemented with secondary analysis of a national household survey in order to map the relative extent of calcium adequacy among different demographics.

RESULTS

Intake of calcium is low in the general population of Bangladesh, with potentially serious and persistent effects on public health. These effects are especially pertinent to young children and reproductive-age women, by virtue of increased physiologic needs, disproportionately poor access to dietary calcium sources, and a confluence of other local determinants of calcium status in these groups.

CONCLUSION

A tablet supplementation program for pregnant women is an appealing approach for the reduction in preeclampsia and preterm birth. Further research is warranted to address the comparative benefit of different promising approaches in children for the prevention of rickets.

Supplementation with Folic Acid, but Not Creatine, Increases Plasma Betaine, Decreases Plasma Dimethylglycine, and Prevents a Decrease in Plasma Choline in Arsenic-Exposed Bangladeshi Adults

BACKGROUND

Folic acid (FA) supplementation facilitates urinary excretion of arsenic, a human carcinogen. A better understanding of interactions between one-carbon metabolism intermediates may improve the ability to design nutrition interventions that further facilitate arsenic excretion.

OBJECTIVE

The objective was to determine if FA and/or creatine supplementation increase choline and betaine and decrease dimethylglycine (DMG).

METHODS

We conducted a secondary analysis of the Folic Acid and Creatine Trial, a randomized trial in arsenic-exposed Bangladeshi adults (n = 605, aged 24-55 y, 50.3% male) who received arsenic-removal water filters. We examined treatment effects of FA and/or creatine supplementation on plasma choline, betaine, and DMG concentrations, measured by LC-tandem mass spectrometry at baseline and at week 12. Group comparisons were between 1) 400 and 800 μg FA/d (FA400 and FA800, respectively) compared with placebo, 2) creatine (3 g/d) compared with placebo, and 3) creatine plus FA400 compared with FA400.

RESULTS

Choline decreased in the placebo group (-6.6%; 95% CI: -10.2%, -2.9%) but did not change in the FA groups (FA400: 2.5%; 95% CI: -0.9%, 6.1%; FA800: 1.4%; 95% CI: -2.5%, 5.5%; P < 0.05). Betaine did not change in the placebo group (-3.5%; 95% CI: -9.3%, 2.6%) but increased in the FA groups (FA400: 14.1%; 95% CI: 9.4%, 19.0%; FA800: 13.0%; 95% CI: 7.2%, 19.1%; P < 0.01). The decrease in DMG was greater in the FA groups (FA400: -26.7%; 95% CI: -30.9%, -22.2%; FA800: -27.8%; 95% CI: -31.8%, -23.4%) than in the placebo group (-12.3%; 95% CI: -18.1%, -6.2%; P < 0.01). The percentage change in choline, betaine, and DMG did not differ between creatine treatment arms and their respective reference groups.

CONCLUSION

Supplementation for 12 wk with FA, but not creatine, increases plasma betaine, decreases plasma DMG, and prevents a decrease in plasma choline in arsenic-exposed Bangladeshi adults. This trial was registered at clinicaltrials.gov as NCT01050556.

Determinants and Consequences of Arsenic Metabolism Efficiency among 4,794 Individuals: Demographics, Lifestyle, Genetics, and Toxicity

BACKGROUND

Exposure to inorganic arsenic (iAs), a class I carcinogen, affects several hundred million people worldwide. Once absorbed, iAs is converted to monomethylated (MMA) and then dimethylated forms (DMA), with methylation facilitating urinary excretion. The abundance of each species in urine relative to their sum (iAs%, MMA%, and DMA%) varies across individuals, reflecting differences in arsenic metabolism capacity.

METHODS

The association of arsenic metabolism phenotypes with participant characteristics and arsenical skin lesions was characterized among 4,794 participants in the Health Effects of Arsenic Longitudinal Study (Araihazar, Bangladesh). Metabolism phenotypes include those obtained from principal component (PC) analysis of arsenic species.

RESULTS

Two independent PCs were identified: PC1 appears to represent capacity to produce DMA (second methylation step), and PC2 appears to represent capacity to convert iAs to MMA (first methylation step). PC1 was positively associated (P <0.05) with age, female sex, and BMI, while negatively associated with smoking, arsenic exposure, education, and land ownership. PC2 was positively associated with age and education but negatively associated with female sex and BMI. PC2 was positively associated with skin lesion status, while PC1 was not. 10q24.32/AS3MT region polymorphisms were strongly associated with PC1, but not PC2. Patterns of association for most variables were similar for PC1 and DMA%, and for PC2 and MMA% with the exception of arsenic exposure and SNP associations.

CONCLUSIONS

Two distinct arsenic metabolism phenotypes show unique associations with age, sex, BMI, 10q24.32 polymorphisms, and skin lesions.

IMPACT

This work enhances our understanding of arsenic metabolism kinetics and toxicity risk profiles.

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. Diabetes diagnosis was based on measures of fasting plasma glucose and 2-h blood glucose. Multivariable models were used to identify metabolites with altered abundance associated with iAs exposure among diabetic and nondiabetic individuals. A total of 132 metabolites were identified to shift in urine or plasma in response to iAs exposure characterized by the sum of iAs metabolites in urine (U-tAs). Although many metabolites were altered in both diabetic and nondiabetic 35 subjects, diabetic individuals displayed a unique response to iAs exposure with 59 altered metabolites including those that play a role in tricarboxylic acid cycle and amino acid metabolism. Taken together, these data highlight the broad impact of iAs exposure on the human metabolome, and demonstrate some specificity of the metabolomic response between diabetic and nondiabetic individuals. These data may provide novel insights into the mechanisms and phenotype of diabetes associated with iAs exposure.

The mechanistic basis of arsenicosis: pathogenesis of skin cancer

Significant amounts of arsenic have been found in the groundwater of many countries including Argentina, Bangladesh, Chile, China, India, Mexico, and the United States with an estimated 200 million people at risk of toxic exposure. Although chronic arsenic poisoning damages many organ systems, it usually first presents in the skin with manifestations including hyperpigmentation, hyperkeratoses, Bowen's disease, squamous cell carcinoma, and basal cell carcinoma. Arsenic promotes oxidative stress by upregulating nicotinamide adenine dinucleotide phosphate oxidase, uncoupling nitric oxide synthase, and by depleting natural antioxidants such as nitric oxide and glutathione in addition to targeting other proteins responsible for the maintenance of redox homeostasis. It causes immune dysfunction and tissue inflammatory responses, which may involve activation of the unfolded protein response signaling pathway. In addition, the dysregulation of other molecular targets such as nuclear factor kappa B, Hippo signaling protein Yap, and the mineral dust-induced proto-oncogene may orchestrate the pathogenesis of arsenic-mediated health effects. The metalloid decreases expression of tumor suppressor molecules and increases expression of pro-inflammatory mitogen-activated protein kinase pathways leading to a tumor-promoting tissue microenvironment. Cooperation of upregulated signal transduction molecules with DNA damage may abrogate apoptosis, promote proliferation, and enhance cell survival. Genomic instability via direct DNA damage and weakening of several cellular DNA repair mechanisms could also be important cancer development mechanisms in arsenic-exposed populations. Thus, arsenic mediates its toxicity by generating oxidative stress, causing immune dysfunction, promoting genotoxicity, hampering DNA repair, and disrupting signal transduction, which may explain the complex disease manifestations seen in arsenicosis.