Arsenic-induced health effects and genetic damage in keratotic individuals: involvement of p53 arginine variant and chromosomal aberrations in arsenic susceptibility

Abstract

In West Bengal, India, more than 6 million people are exposed to arsenic through drinking water. Chronic arsenic exposure results in several multisystemic non-cancerous as well as cancerous effects in humans. Among non-cancerous effects, arsenic-specific skin lesions, conjunctivitis, peripheral neuropathy and respiratory diseases are prominent. One of the major consequences of chronic arsenic exposure is keratosis, the precancerous state of skin cancer. The tumor suppressor protein p53 consists of a polymorphism proline72arginine reported to be associated with various types of cancers. Previously we have reported that the p53 codon 72 arginine (Arg) homozygous genotype is associated with the development of arsenic-induced keratosis. In the present study we have investigated the distribution of health effects and chromosomal aberrations (CAs) in the individuals with keratosis. We have compared individuals with keratosis with those without arsenic-induced skin lesions but drinking similar level of arsenic-contaminated water. Attempts have also been made to find out the association of the p53 risk genotype with health effects and chromosomal aberrations. This study comprises of 349 unrelated exposed individuals (162 individuals with keratosis and 187 individuals without arsenic-specific skin lesions) from highly arsenic-affected districts of West Bengal, India. The results showed that health effects (i.e. peripheral neuropathy, conjunctivitis and respiratory illness) and chromosomal aberrations were significantly higher in the keratotic group compared to individuals with no skin lesions. Moreover, individuals with the arginine homozygous genotype showed increased levels of chromosomal aberrations compared to individuals with other genotypes; however, we did not find any significant association of the risk genotype with health effects. This study suggests that individuals with keratosis are more susceptible to arsenic-induced health effects and genetic damage and that the arginine variant of p53 can further influence the repair capacity of arsenic-exposed individuals, leading to increased accumulation of chromosomal aberrations.