Antithetical effect of tumor necrosis factor-alphagene polymorphism on coal workers' pneumoconiosis (CWP)

Usefulness of Biomarkers in Work-Related Airway Disease

Determination of biomarkers may be useful in the surveillance of occupational exposure and workers' health. The possibility of predicting development/clinical course of specific disorders or current disease, diagnosing in early steps, and health condition monitoring is a real necessity. Various agents present in the workplace environment (or their metabolites) can be measured in samples possessed from human body (blood and urine, saliva, etc.). On the other hand, inhalant exposure may induce specific or non-specific, local or systemic, acute or chronic biological response expressed by synthesis or releasing specific or non-specific substances/mediators that also can be determined in blood, nasal and bronchial lavage or sputum, tear fluid, exhaled breath, etc. The least is known about genetic markers which may predict individual susceptibility to develop some work-related disorders under the influence of occupational exposure. Due to common exposure to inhalant agents at workplace, researches on biomarkers that allow to inspect the impact of exposure to humans' health are still needed. The authors of this article summarize the utility of biomarkers' determination in work-related airway diseases in a recent clinical approach.

Coal mine dust lung disease in the modern era

Coal workers' pneumoconiosis (CWP), as part of the spectrum of coal mine dust lung disease (CMDLD), is a preventable but incurable lung disease that can be complicated by respiratory failure and death. Recent increases in coal production from the financial incentive of economic growth lead to higher respirable coal and quartz dust levels, often associated with mechanization of longwall coal mining. In Australia, the observed increase in the number of new CWP diagnoses since the year 2000 has necessitated a review of recommended respirable dust exposure limits, where exposure limits and monitoring protocols should ideally be standardized. Evidence that considers the regulation of engineering dust controls in the mines is lacking even in high-income countries, despite this being the primary preventative measure. Also, it is a global public health priority for at-risk miners to be systemically screened to detect early changes of CWP and to include confirmed patients within a central registry; a task limited by financial constraints in less developed countries. Characteristic X-ray changes are usually categorized using the International Labour Office classification, although future evaluation by low-dose HRCT) chest scanning may allow for CWP detection and thus avoidance of further exposure, at an earlier stage. Preclinical animal and human organoid-based models are required to explore potential re-purposing of anti-fibrotic and related agents with potential efficacy. Epidemiological patterns and the assessment of molecular and genetic biomarkers may further enhance our capacity to identify susceptible individuals to the inhalation of coal dust in the modern era.

Association between Genetic Variants of Transforming Growth Factor-β1 and Susceptibility of Pneumoconiosis: A Meta-analysis

Background:

Transforming growth factor-beta 1 (TGF-β1) and gene variants have been extensively studied in various human diseases. For example, TGF-β1 polymorphisms were associated with fibrosis and pneumoconiosis, but the data remained controversial. The aim of this meta-analysis was to assess the association between TGF-β1 −509 C>T [rs1800469], +869 T>C [rs1800470], and +915 G>C [rs1800471] polymorphisms and pneumoconiosis.

Methods:

A comprehensive literature search was conducted through searching in PubMed, Embase, the Chinese Biomedical Database, and the Wei Pu (Chinese) Database by the end of April 2016. Eleven publications with 21 studies were included in this meta-analysis, covering a total of 4333 patients with pneumoconiosis and 3478 controls. Study quality was assessed, and heterogeneity and publication bias were measured. All statistical analyses were performed using STATA version 12.0 (StataCorp, College Station, TX, USA) software.

Results:

The data showed significant associations between TGF-β1 −509 C>T polymorphism and the risk of pneumoconiosis development (T vs. C, odds ratio [OR] = 1.35, 95% confidence interval [CI]: 1.00–1.81, P = 0.046); between TGF-β1 +915 G>C polymorphism and the pneumoconiosis risk (C vs. G, OR = 1.69, 95% CI: 1.19–2.40, P = 0.004; CG vs. GG, OR = 1.79, 95% CI: 1.23–2.60, P = 0.002; CC+CG vs. GG, OR = 1.80, 95% CI: 1.24–2.61, P = 0.002). In addition, the subgroup analysis of ethnicity versus pneumoconiosis types indicated a significant association of silicosis among Asian populations but not that of coal workers’ pneumoconiosis in Caucasian populations. In contrast, no significant association was exhibited between TGF-β1 +869 T>C polymorphism and risk of pneumoconiosis.

Conclusion:

The polymorphisms of both TGF-β1 −509 C>T and +915 G>C are associated with increased risk of pneumoconiosis.

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.

Associations between tumor necrosis factor alpha gene -238 G/A and -308 G/A polymorphisms and the risk of pneumoconiosis: update of a meta-analysis

OBJECTIVES

Tumor necrosis factor alpha (TNF-α) gene (-238 G/A [rs361525] and -308 G/A [rs1800629]) polymorphisms have been extensively studied in relation to various diseases, several epidemiologic studies have been performed to investigate the associations of TNF-α gene polymorphisms with pneumoconiosis; however, the results of these studies were not entirely consistent. In an effort to clarify earlier inconclusive results, we performed this meta-analysis of case-control genetic association studies.

METHODS

We identified eligible studies by searching the relevant databases, including PubMed, Embase, Web of Science, CBMdisc, CNKI, and Google Scholar, until February 15, 2013. Additionally, hand searching of the references of identified articles were performed. Heterogeneity and publication bias across studies were determined and the meta-analysis was performed by Stata 11.0.

RESULTS

Fourteen articles involving 20 studies were included in the final meta-analysis, covering a total of 1935 pneumoconiosis cases and 3753 controls. The results showed evidence for significant association between TNF-α gene -308 G/A polymorphism and pneumoconiosis risk, suggesting that TNF-α gene -308 A allele may be a risk factor for pneumoconiosis (for A allele vs. G allele: OR = 1.41, 95% CI = 1.10-1.81, p = 0.01; for A/A + G/A vs. G/G: OR = 1.52, 95% CI = 1.21-1.91, p < 0.01). For TNF-α gene -238 G/A polymorphism, no significant association was found between this genetic variation and pneumoconiosis risk.

CONCLUSIONS

This meta-analysis indicates that TNF-α gene -308 G/A polymorphism is associated with an increased pneumoconiosis risk.

Association between tumor necrosis factor-α 308G/A gene polymorphism and silicosis susceptibility: a meta-analysis

Background

Tumor necrosis factor-α (TNF-α) 308 G/A gene polymorphism has been reported to be associated with susceptibility to silicosis. However, the relevant study results are still inconsistent.

Objective and Methods

A meta-analysis was performed in order to drive a more precise estimation of the relationship between TNF-α-308 G/A gene polymorphism and susceptibility to silicosis. Electronic databases were searched and nine separate studies were included. The pooled odds ratios (ORs) and the corresponding 95% confidence internal (CI) were calculated by a fixed effect model.

Results

A total of 1267 cases and 1214 controls were included. In the overall analysis, significantly increased silicosis risk was found (for GA+AA vs. GG OR=1.45, 95%CI: 1.20-1.760, P=1.58E4; for GA vs. GG: OR=1.53, 95%CI=1.25-1.86, P=3.11E5; for A allele vs. G allele: OR=1.27, 95%CI=1.08-1.50, P= 0.004). In the subgroup analysis, significantly increased silicosis risk was also found among Asians (for GA+AA vs. GG: OR=1.63, 95%CI=1.27-2.08, P=1.01E4), for GA vs. GG: OR=1.71, 95%CI=1.33-2.20, P=3.44E5), for A allele vs. G allele: OR=1.45, 95%CI=1.17-1.80, P=0.001). However, no significantly increased risk was found among non-Asians for all genetic models.

Conclusions

TNF-α-308 G/A polymorphism might lead to an increased risk of silicosis susceptibility, especially for Asians. However, further studies with large sample sizes should be conducted to confirm the association.

Tumour necrosis factor-alpha gene polymorphisms in asbestos-induced diseases

BACKGROUND

Tumour necrosis factor (TNF)-alpha influences the pathogenesis of lung fibrosis and carcinogenesis in normal cells. Polymorphisms of this gene have been suggested to be associated with susceptibility to lung diseases.

METHODS

Association studies were performed in German subjects, using control subjects (n = 177), pulmonary fibrosis patients (n = 612) and bronchial carcinoma patients (n = 374).

RESULTS

Compared with a healthy (control) group, a significant result could be obtained for the asbestosis (patient) group (crude odds ratio (OR(crude)) = 1.57; 95% confidence interval (CI) 1.05-2.36; p = 0.03), especially with severe lung asbestosis (OR(crude) = 4.15; 95% CI 1.06-16.16; p = 0.04). A significant association was revealed when comparing asbestosis patients (OR(crude) = 4.08; 95% CI 1.53-10.54; p = 0.004 and OR(adjusted) = 3.89; 95% CI 1.49-10.17; p = 0.006) with asbestos-induced lung cancer patients.

CONCLUSION

The results confirm the hypothesis that TNF-alpha polymorphisms are associated with asbestos-induced fibrotic or malignant lung diseases in Germans.

Progression of pneumoconiosis in coal miners after cessation of dust exposure: a longitudinal study based on periodic chest X-ray examinations in Hokkaido, Japan

BACKGROUND

The progression rate of pneumoconiosis in retired coal miners over ten years has not been studied in Japan.

METHODS

A retrospective longitudinal study was undertaken using chest X-rays of 1091 pneumoconiosis subjects in Hokkaido, Japan between 1985 and 2005.

RESULTS

The final numbers of subjects were 207 (19% of the entry) after 1 decade and 85 (8%) after 2 decades. Sixty-two percent of 207 subjects after 1 decade and 29% of 85 showed progression in 2 decades. Thirty-one percent of ILO category 1 and 55% of category 2 subjects showed progression to complicated pneumoconiosis after 1 decade, and 6% (4 of 64) of category 1 and 6% (5 of 77) of category 2 subjects progressed to complicated pneumoconiosis during 2 decades.

CONCLUSION

The progression of pneumoconiosis was observed after the cessation of dust exposure, especially during the first 10 years.

Possible effect of gene polymorphisms on the release of TNFα and IL1 cytokines in coal workers' pneumoconiosis

It has been shown that coal dust exposure stimulates inflammatory response leading to increased release of cytokines from monocytes such as TNF-alpha and IL1. These released cytokines play the key role in the pathogenesis of pneumoconiosis including coal workers' pneumoconiosis. In this study, we investigated TNFA, IL1A, IL1B and IL1RA genes variations on basal, lipopolysaccharide and coal dust-induced cytokine release from blood monocytes of homozygous allele and minor variant allele carriers in Turkish coal workers and CWP patients. According to the genotyping results, TNFA -238 gene polymorphism was found as a risk factor in CWP development (OR=3.79) and to in vitro results; release of both TNF-alpha and IL1 cytokines from the monocytes in CWP patients was significantly increased compared to the healthy workers. Also, LPS and coal dust stimulated release of TNF-alpha, which was significantly higher in allele 2 carriers compared to subjects carrying allele 1 in both the groups. These data suggest that the coal dust-induced release of TNF-alpha from monocytes may be a useful biomarker of CWP.

Association of cytokine gene polymorphisms in CWP and its severity in Turkish coal workers

BACKGROUND

Cytokines appear to play a key role in some inflammatory reactions affecting the interactions among pro- and anti-inflammatory mechanisms that result in several diseases such as coal workers' pneumoconiosis (CWP). In this study, to determine the cytokine gene profiles of Turkish coal miners, we performed genotyping analysis to investigate the polymorphisms of CWP-related pro-inflammatory (TNFA, IL1A, IL1B, and IL6) and anti-inflammatory cytokines (IL-1RN and TGFB1). An additional goal was to observe whether these cytokine gene polymorphisms influence the development risk and severity of.

METHODS

Genotyping was carried out by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique.

RESULTS

TNFA (-238) gene polymorphism principally affected CWP development and severity (OR = 3.47: 95% CI, 1.12-10.77 and OR = 4.30: 95% CI, 1.25-14.74, respectively) and also risk of CWP (OR = 3.79: 95% CI, 1.37-10.46). The TNFA (-308) variant was associated with a risk for the CWP severity (OR = 2.84: 95% CI, 1.08-7.39). A protective effect of IL6 was found on the development (OR = 0.48: 95% CI, 0.21-0.93) and severity of CWP (OR = 0.37: 95% CI, 0.15-0.91).

CONCLUSIONS

We suggest that TNFA (-238) variant may be a risk factor in both development and the severity of CWP, while TNFA (-308) variant seems to be important only in disease severity. On the other hand, IL6 variant may have a protective effect on the development and disease severity.

Mannose-binding lectin gene polymorphisms and the development of coal workers' pneumoconiosis in Japan

BACKGROUND

Infection, immunity and genetic factors play roles in the development of coal worker's pneumoconiosis (CWP) and progressive massive fibrosis (PMF). We investigate whether the genetic polymorphisms of mannose-binding lectin (MBL), one of the key molecules of innate immunity, is associated with the susceptibility to CWP.

METHOD

MBL2 polymorphisms (codon54, promoter -221, and -550) were assessed for 197 patients with CWP (119 with nodular CWP and 78 with PMF) and 153 unexposed regional controls. Serum MBL concentrations were measured in 119 CWP patients.

RESULTS

Three polymorphisms were in linkage disequilibrium for all study populations. The MBL2 genotype and haplotypes were associated with lower serum MBL levels. The frequency of such MBL2 genotype and haplotypes were significantly higher in patients with CWP compared to controls, whereas these distributions were not different between patients with nodular CWP and those with PMF.

CONCLUSION

MBL2 polymorphisms and haplotypes may be one of the genetic determinants for the susceptibility of CWP.

Genetic susceptibility in pneumoconiosis

A large number of cellular mediators such as cytokines, antioxidants and growth factors have been implicated in the pathogenesis of chronic inflammatory and fibrotic diseases. Common functional polymorphisms in these genes have been shown to influence individual susceptibility to these diseases. Silicosis, coal worker pneumoconiosis, progressive massive fibrosis and berylliosis are examples of fibrotic pneumoconiosis and are characterized by irreversible fibrotic lesions in the lung resulting from chronic dust inhalation. Although the materials are the major contributory factors of the disease pathogenesis, not all individuals exposed to similar levels develop disease. This suggests that there is a genetic predisposition to their development. Therefore, an understanding of genetic variability and the interaction between genetic and environmental factors is crucial to the identification of high-risk individuals and prevention and treatment of these diseases.

Association of TNFA promoter region haplotype in Behçet's Disease

Although the etiology of Behçet's Disease (BD; MIM 109650) remains to be clearly elucidated, levels of tumor necrosis factor alpha (TNF-alpha) have been reported to be significantly elevated in BD patients, and TNF-alpha blockers have been demonstrated to exhibit some degree of therapeutic efficacy for a certain subset of BD sufferers. In this study, we have conducted an analysis of the TNFA haplotypes in the promoter response element that affect the binding affinity of specific transcription factors, in order to characterize their association with the clinical features of BD. Six polymorphisms in the promoter region of TNFA were genotyped in 254 BD patients and 344 control subjects, via the PCR-RFLP technique. TNFA -1031*C, -863*A and -308*G alleles were associated with an increased risk of BD (p=0.030, OR=1.4; p=0.008, OR=1.5; p=0.010, OR=1.8, respectively). The sole TNFA haplotype -1031C-863A-857C-376G-308G-238G, was associated with a 1.6 fold increase in the risk of BD, whereas the TNFA haplotype -1031T-863C-857C-376G-308A-238G was associated with a 0.6 decreased risk of BD. The TNFA -1031*C, -863*A, -857*C and -308*G alleles were significantly associated with BD. The findings of this study, collectively, indicate that TNFA haplotypes in the promoter response elements may exert significant influence on susceptibility to BD.

Gene polymorphisms of fibrinolytic enzymes in coal workers' pneumoconiosis

The authors assessed the gene polymorphisms of missense C/T polymorphism in exon 6 of the urokinase-plasminogen activator (PLAU) gene (PLAU P141L), Alu-repeat in intron 8 of the tissue-type plasminogen activator (PLAT) gene (PLAT TPA25 Alu insertion), and 4G/5G in the promoter region of the serine proteinase inhibitor, clade E (SERPINE) or plasminogen activator inhibitor type 1 gene (SERPINE1 -675 4G/5G) in 153 healthy volunteers and 154 retired coal miners with coal miners' pneumoconiosis (CWP). The CWP subjects included 94 individuals with simple pneumoconiosis and 60 individuals with progressive massive fibrosis presenting with worse pulmonary function. The distributions of genotypes of these three genes did not differ between the control and CWP subjects or between subjects with simple pneumoconiosis and those with progressive massive fibrosis. However, by assessing duration of work and its interaction with genotypes by means of logistic regression, the authors found the missense C/T polymorphism in exon 6 of the PLAU gene to be an effect modifier of the association between work duration and the development of progressive massive fibrosis.