The influence of genetic polymorphisms of GSTP1 on the development of asbestosis

The role of polymorphisms in glutathione-related genes in asbestos-related diseases

BACKGROUND

The study investigated the influence of GCLC, GCLM, GSTM1, GSTT1 and GSTP1 polymorphisms, as well as the influence of interactions between polymorphism and interactions between polymorphisms and asbestos exposure, on the risk of developing pleural plaques, asbestosis and malignant mesothelioma (MM).

SUBJECTS AND METHODS

The cross sectional study included 940 asbestos-exposed subjects, among them 390 subjects with pleural plaques, 147 subjects with asbestosis, 225 subjects with MM and 178 subjects with no asbestos-related disease. GCLC rs17883901, GCLM rs41303970, GSTM1 null, GSTT1 null, GSTP1 rs1695 and GSTP1 rs1138272 genotypes were determined using PCR based methods. In statistical analysis, logistic regression was used.

RESULTS

GSTT1 null genotype was associated with the decreased risk for pleural plaques (OR = 0.63; 95% CI = 0.40-0.98; p = 0.026) and asbestosis (OR = 0.51; 95% CI = 0.28-0.93; p = 0.028), but not for MM. A positive association was found between GSTP1 rs1695 AG + GG vs. AA genotypes for MM when compared to pleural plaques (OR = 1.39; 95% CI = 1.00-1.94; p = 0.049). The interactions between different polymorphisms showed no significant influence on the risk of investigated asbestos-related diseases. The interaction between GSTT1 null polymorphism and asbestos exposure decreased the MM risk (OR = 0.17; 95% CI = 0.03-0.85; p = 0.031).

CONCLUSIONS

Our findings suggest that GSTT1 null genotype may be associated with a decreased risk for pleural plaques and asbestosis, may modify the association between asbestos exposure and MM and may consequently act protectively on MM risk. This study also revealed a protective effect of the interaction between GSTP1 rs1695 polymorphism and asbestos exposure on MM risk.

Addressing the Social Determinants of Health to Reduce Tobacco-Related Disparities

INTRODUCTION

Comprehensive tobacco prevention and control efforts that include implementing smoke-free air laws, increasing tobacco prices, conducting hard-hitting mass media campaigns, and making evidence-based cessation treatments available are effective in reducing tobacco use in the general population. However, if these interventions are not implemented in an equitable manner, certain population groups may be left out causing or exacerbating disparities in tobacco use. Disparities in tobacco use have, in part, stemmed from inequities in the way tobacco control policies and programs have been adopted and implemented to reach and impact the most vulnerable segments of the population that have the highest rates of smokings (e.g., those with lower education and incomes).

METHODS

Education and income are the 2 main social determinants of health that negatively impact health. However, there are other social determinants of health that must be considered for tobacco control policies to be effective in reducing tobacco-related disparities. This article will provide an overview of how tobacco control policies and programs can address key social determinants of health in order to achieve equity and eliminate disparities in tobacco prevention and control.

RESULTS

Tobacco control policy interventions can be effective in addressing the social determinants of health in tobacco prevention and control to achieve equity and eliminate tobacco-related disparities when they are implemented consistently and equitably across all population groups.

CONCLUSIONS

Taking a social determinants of health approach in tobacco prevention and control will be necessary to achieve equity and eliminate tobacco-related disparities.

Gene-environment interaction from international cohorts: impact on development and evolution of occupational and environmental lung and airway disease

Environmental and occupational pulmonary diseases impose a substantial burden of morbidity and mortality on the global population. However, it has been long observed that only some of those who are exposed to pulmonary toxicants go on to develop disease; increasingly, it is being recognized that genetic differences may underlie some of this person-to-person variability. Studies performed throughout the globe are demonstrating important gene-environment interactions for diseases as diverse as chronic beryllium disease, coal workers' pneumoconiosis, silicosis, asbestosis, byssinosis, occupational asthma, and pollution-associated asthma. These findings have, in many instances, elucidated the pathogenesis of these highly complex diseases. At the same time, however, translation of this research into clinical practice has, for good reasons, proceeded slowly. No genetic test has yet emerged with sufficiently robust operating characteristics to be clearly useful or practicable in an occupational or environmental setting. In addition, occupational genetic testing raises serious ethical and policy concerns. Therefore, the primary objective must remain ensuring that the workplace and the environment are safe for all.

The influence of gene-gene and gene-environment interactions on the risk of asbestosis

This study investigated the influence of gene-gene and gene-environment interactions on the risk of developing asbestosis. The study comprised 262 cases with asbestosis and 265 controls with no asbestos-related disease previously studied for MnSOD, ECSOD, CAT, GSTT1, GSTM1, GSTP1, and iNOS polymorphisms. Data on cumulative asbestos and smoking were available for all subjects. To assess gene-gene and gene-environmental interactions, logistic regression was used. The associations between MnSOD Ala −9Val polymorphism and the risk of asbestosis and between iNOS genotypes and asbestosis were modified by CAT –262 C > T polymorphism (P = 0.038; P = 0.031). A strong interaction was found between GSTM1-null polymorphism and smoking (P = 0.007), iNOS (CCTTT)_n polymorphism and smoking (P = 0.054), and between iNOS (CCTTT)_n polymorphism and cumulative asbestos exposure (P = 0.037). The findings of this study suggest that the interactions between different genotypes, genotypes and smoking, and between genotypes and asbestos exposure have an important influence on the development of asbestosis and should be seriously considered in future research on occupational/environmental asbestos-related diseases.

The role and frequency of glutathione s-transferase P1 polymorphism in Iranian patients affected with reflux esophagitis

Reflux esophagitis is a common complication of the gastroesophageal reflux disease. Glutathione s-transferases (GSTs) have important role in the protection of cells from the products of oxidative stress. GSTP1*B allele has a correlation with susceptibility to several diseases. In this case-control study, the role and frequency of GSTP1 polymorphism was evaluated in Iranian patients with erosive reflux esophagitis. Seventy patients with erosive reflux esophagitis and 75 normal individuals were enrolled in this study. The grade of esophagitis was determined via endoscopy. DNA was extracted from venous blood of each subject using the salting out method. GSTP1 genetic polymorphisms were detected using the polymerase chain reaction restriction fragment length polymorphism method. There was a significant difference in GSTP1 genotype frequency between patients and normal groups (P= 0.006). Also, in the patient group, the grade B of esophagitis was significantly associated with variant GSTP1 genotype (P= 0.028). The rate of throat pain symptom was higher in the no-variant group (P < 0.036). The GSTP1*B allele frequency in Iranian normal groups is similar to Orientals. Reflux esophagitis are more commonly found in variant (*B/*B and *A/*B) GSTP1 genotypes. In addition, GSTP1 polymorphism is correlated with a higher grade of esophagitis.

Manganese and extracellular superoxide dismutase polymorphisms and risk for asbestosis

Manganese and extracellular superoxide dismutases (SOD2 and SOD3) are part of the enzymatic defence against reactive oxygen species, which are involved in the pathogenesis of asbestosis. This study investigates whether SOD2Ala − 9Val and SOD3 Arg213Gly genetic polymorphisms represent risk factors for asbestosis in workers exposed to asbestos. The study included 262 cases with asbestosis and 265 controls with no asbestos-related disease. Cumulative asbestos exposure was calculated for each subject. A real-time PCR assay was introduced for genotyping. Logistic regression analysis was used to assess asbestosis risk. Asbestosis was associated with the homozygous SOD2 − 9Ala/Ala genotype (OR = 1.50, 95% CI 1.01–2.24), whereas the association for the SOD3 Arg/Gly genotype was not significant (OR = 1.63, 95% CI 0.62–4.27). The finding that the SOD2 − 9Ala/Ala genotype increases the risk for asbestosis indicates that, in addition to asbestos exposure, genetic factors may also have a significant influence on the development of asbestosis.

Asbestosis and catalase genetic polymorphism

Catalase (CAT) is part of the enzymatic defense system against reactive oxygen species (ROS), known to be involved in the pathogenesis of asbestosis. This study investigates whether CAT -262 C>T genetic polymorphism influences the risk of asbestosis in workers occupationally exposed to asbestos.The nested case-control study included 262 cases with asbestosis and 265 controls with no asbestos-related disease. Data on cumulative asbestos exposure and smoking were available. A real-time PCR assay was introduced for genotyping CAT -262 C>T promoter polymorphism.A slightly elevated risk of asbestosis was observed in subjects with the CAT -262 TT genotype compared to others (OR=1.36, CI 0.70-2.62). This risk did not change substantially after adjustment by sex, age, and smoking, but the involvement of cumulative asbestos exposure changed the OR to 1.91 (CI 0.93-3.91). These findings indicate that the CAT -262 TT genotype may be slightly associated with an increased risk of asbestosis. No synergistic effect was found between cumulative asbestos exposure and the CAT -262 TT genotype, but cumulative asbestos exposure acted as a confounder. These results are an important contribution to understanding the interactions between genetic and environmental factors that may modify the risk of asbestosis.