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Evaluation of the health effects, genetic damage and dna methylation induced by arsenic through drinking water

IR@IICB: CSIR-Indian Institute of Chemical Biology, Kolkata


Field	Value

Title	Evaluation of the health effects, genetic damage and dna methylation induced by arsenic through drinking water

Creator	Paul, Somnath

Subject	Cell Biology & Physiology Molecular & Human Genetics

Description	Arsenic toxicity is a pandemic concern as addressed by the WHO to be one of the major natural calamities till date. More than 137 million individuals in nearly 70 nations are affected by arsenic mainly through drinking underground water. In the state of West Bengal, this scenario is grim where nearly 26 million individuals in 9 out of 18 districts are affected by arsenic through drinking water. The arsenic content in these regions is nearly 10-20 times compared to the MPL of the WHO, i.e >10g/L. Although several preventive measures have been initiated by installing arsenic filters in these regions, but still several regions are consuming arsenic lessened drinking water, that are still more than the WHO standard of 10g/L. Chronic exposure to arsenic leads to various types of patho-physiological end points like dermatological lesions, peripheral neuropathy, respiratory disorders and eye problems, etc in humans including several types of cancers. Two epidemiological studies were conducted separately, to identify the ameliorative effect of reduction in arsenic through drinking water. In a two wave cross-sectional study, there were 189 arsenicosis patients and 171 unexposed individuals were recruited at two time points, (2005–06 and 2010–11) with concomitant decrease in the level of arsenic exposure through drinking water for the arsenicosis group in 2010–11. Parameters evaluated in this study included dermatological, non-dermatological health status and cytogenetic damage. We identified that reduction in arsenic through drinking water (190.1 g/l in 2005-06 to 37.94 g/l in 2010-11) had a positive effect on amelioration towards arsenic induced dermatological lesions (p<0.01) and cytogenetic damage (p<0.001). We also found that there was a significant (p<0.001) rise in the incidence of each of the non-dermatological diseases, that is, peripheral neuropathy,conjunctivitis and respiratory distress over the period. This study was conducted in a study population who were consuming significantly higher amount of arsenic through drinking water;over the past 5 years the content was significantly reduced but still it was higher than the WHO recommendation. We considered another study group, where the drinking water arsenic was below the WHO recommended limit. In this cohort study, we observed that the mean MN frequency in arsenic exposed individuals with skin lesions as well as no skin lesions reduced drastically (p<0.001) when compared between 2004-05 and 2010-11.Arsenic, is a xenobiotic substance and is biotransformed in the body to it’s methylated species by using the physiological S-Adenosyl Methionine (SAM). SAM determines methylation status of the genome and arsenic metabolism leads to depletion of this indigenous SAM leading to an epigenetic disequilibrium. Since epigenetics is one of the major phenomenon at the interface between the environment and human health impact, it’s disequilibrium by arsenic induces alterations in the chromatin compaction, gene expression, genomic stability and a host of biomolecular interactions, the interactome within the cell. Since arsenic is not mutagenic but is carcinogenic in nature; hence, arsenic induced epimutagenesis has come to the forefront since it determines the transcriptional and genomic integrity of the cell.

Date	2015

Type	Thesis NonPeerReviewed

Format	application/pdf

Identifier	http://www.eprints.iicb.res.in/2424/1/SOMNATH_PAUL_THESIS_for_CD.pdf Paul, Somnath (2015) Evaluation of the health effects, genetic damage and dna methylation induced by arsenic through drinking water. PhD thesis, JU.

Relation	http://www.eprints.iicb.res.in/2424/