Association between the tumour necrosis factor-α-308G/A polymorphism and chronic obstructive pulmonary disease: an update

Association of TNF-α (-308G/A) Gene Polymorphism with Changes in Circulating TNF-α Levels in Response to CPAP Treatment in Adults with Coronary Artery Disease and Obstructive Sleep Apnea

RATIONALE

We recently demonstrated that patients with coronary artery disease (CAD) and obstructive sleep apnea (OSA) carrying the tumor necrosis factor-alpha (TNF-α) A allele had increased circulating TNF-α levels compared with the ones carrying the TNF-α G allele. In the current study, we addressed the effect of TNF-α (-308G/A) gene polymorphism on circulating TNF-α levels following continuous positive airway pressure (CPAP) therapy.

METHODS

This study was a secondary analysis of the RICCADSA trial (NCT00519597) conducted in Sweden. CAD patients with OSA (apnea-hypopnea index) of ≥15 events/h and an Epworth Sleepiness Scale (ESS) score of <10 were randomized to CPAP or no-CPAP groups, and OSA patients with an ESS score of ≥10 were offered CPAP treatment. Blood samples were obtained at baseline and 12-month follow-up visits. TNF-α was measured by immunoassay (Luminex, R&D Systems). Genotyping of TNF-α-308G/A (single nucleotide polymorphism Rs1800629) was performed by polymerase chain reaction-restriction fragment length polymorphism.

RESULTS

In all, 239 participants (206 men and 33 women; mean age 64.9 (SD 7.7) years) with polymorphism data and circulating levels of TNF-α at baseline and 1-year follow-up visits were included. The median circulating TNF-α values fell in both groups between baseline and 12 months with no significant within- or between-group differences. In a multivariate linear regression model, a significant change in circulating TNF-α levels from baseline across the genotypes from GA to GA and GA to AA (standardized β-coefficient -0.129, 95% confidence interval (CI) -1.82; -0.12; p = 0.025) was observed in the entire cohort. The association was more pronounced among the individuals who were using the device for at least 4 h/night (n = 86; standardized β-coefficient -2.979 (95% CI -6.11; -1.21); p = 0.004)), whereas no significant association was found among the patients who were non-adherent or randomized to no-CPAP. The participants carrying the TNF-α A allele were less responsive to CPAP treatment regarding the decline in circulating TNF-α despite CPAP adherence (standardized β-coefficient -0.212, (95% CI -5.66; -1.01); p = 0.005).

CONCLUSIONS

Our results suggest that TNF-α (-308G/A) gene polymorphism is associated with changes in circulating TNF-α levels in response to CPAP treatment in adults with CAD and OSA.

Genetic Variants Associated with Chronic Obstructive Pulmonary Disease Risk: Cumulative Epidemiological Evidence from Meta-Analyses and Genome-Wide Association Studies

Background

Last two decades, many association studies on genetic variants and chronic obstructive pulmonary disease (COPD) risk have been published. But results from different studies are inconsistent. Therefore, we performed this article to systematically evaluate results from previous meta-analyses and genome-wide association studies (GWASs). Material and Methods. Firstly, we retrieved meta-analyses in PubMed, Embase, and China National Knowledge Infrastructure and GWASs in PubMed and GWAS catalog on or before April 7th, 2022. Then, data were extracted and screened. Finally, two main methods—Venice criteria and false-positive report probability test—were used to evaluate significant associations.

Results

As a result, eighty-eight meta-analyses and 5 GWASs were deemed eligible for inclusion. Fifty variants in 26 genes obtained from meta-analyses were significantly associated with COPD risk. Cumulative epidemiological evidence of an association was graded as strong for 10 variants in 8 genes (GSTM1, CHRNA, ADAM33, SP-D, TNF-α, VDBP, HMOX1, and HHIP), moderate for 6 variants in 5 genes (PI, GSTM1, ADAM33, TNF-α, and VDBP), and weak for 40 variants in 23 genes. Five variants in 4 genes showed convincing evidence of no association with COPD risk in meta-analyses. Additionally, 29 SNPs identified in GWASs were proved to be noteworthy based on the FPRP test.

Conclusion

In summary, more than half (52.38%) of genetic variants reported in previous meta-analyses showed no association with COPD risk. However, 13 variants in 9 genes had moderate to strong evidence for an association. This article can serve as a useful reference for further studies.

Blocking tumor necrosis factor-α delays progression of chronic obstructive pulmonary disease in rats through inhibiting MAPK signaling pathway and activating SOCS3/TRAF1

The present study was conducted in order to study the detailed molecular mechanism of tumor necrosis factor (TNF)-α in chronic obstructive pulmonary disease (COPD). The rats were treated with cigarette smoke (CS) and lipopolysaccharide (LPS) to establish the COPD model. Next, the changes in lung injury in COPD rats with TNF-α knockdown was tested. Meanwhile, the regulation of TNF-α on MAPK pathway and its downstream molecules (SOCS3/TRAF1) was determined by western blotting. On this basis, the activation of MAPK and inhibition of SOCS3/TRAF1 was also examined. Subsequently, the lung function was tested with the plethysmograph, the cells of bronchoalveolar lavage fluid was counted and classified. Furthermore, lung tissue sections were stained with hematoxylin and eosin to verify whether the treatment of MAPK pathway and downstream molecules affected the effect of TNF-α knockdown on COPD. The present study showed that TNF-α knockdown could alleviate the decrease in the function and inflammatory injury of the lungs of rats with COPD. Western blot analysis verified that TNF-α knockdown could inhibit the activation of MAPK pathway and increase the expression of SOCS3/TRAF1. The following experimental results showed that the relief of lung injury caused by TNF-α knockdown could be deteriorated by activating MAPK pathway. It was also found that the symptom of COPD was decreased following transfection with sh-TNF-α but worsened by SOCS3/TRAF1 knockdown. Overall, TNF-α knockdown inhibited the activation of MAPK pathway and increased the expression of SOCS3/TRAF1, thus delaying the process of COPD.

Association analysis of genetic variants in the ghrelin and tumor necrosis factor α genes and the risk for non-Hodgkin's lymphoma in Kuwaitis

BACKGROUND:

Non-Hodgkin’s lymphoma (NHL) is the most common hematological malignancy in the world. Many etiologic factors have been implicated in the risk of developing NHL, including genetic susceptibility and obesity. Single-nucleotide polymorphisms (SNPs) in Ghrelin (GHRL), an anti-inflammatory hormone, and tumor necrosis factor α (TNF-α), an inflammatory cytokine, have been independently associated with the risk for obesity and NHL.

OBJECTIVE:

To investigate the association between SNPs in GHRL and TNF-α and the risk for NHL and obesity in Kuwaitis.

METHODS:

We recruited 154 Kuwaiti NHL patients and 217 controls. Genotyping was performed for rs1629816 (GHRL promoter region), rs35684 (GHRL 3’ untranslated region), and rs1800629 (TNF-α promoter region). Logistic regression analysis was performed to assess the association of the investigated SNPs with NHL and the relationship between the selected SNPs with BMI in each group separately.

RESULTS:

We show that rs1629816 GG was associated with an increased risk for NHL in our sample (p= 0.0003, OR 1.82; CI: 1.31–2.54). None of the investigated SNPs were associated with obesity, nor was obesity found to be associated with the risk for NHL.

CONCLUSIONS:

Our study demonstrates an association between rs1629816, a SNP in the GHRL regulatory region, and NHL in Kuwaitis.

Correlation between TNF-α -308 and +489 Gene Polymorphism and Acute Exacerbation of Chronic Obstructive Pulmonary Diseases

Acute exacerbation of chronic obstructive pulmonary disease (AECOPD) is becoming a common respiratory disease, leading to increased morbidity and mortality worldwide. Tumor necrosis factor-alpha (TNF-α) is a powerful proinflammatory cytokine involved in the pathogenesis of AECOPD. Therefore, we proposed a close correlation between the TNF-α polymorphism [-308G/A (rs1800629), +489G/A (rs1800610)] and the disease progress of patients with AECOPD. Comparison of the TNF-α genotypes between the 198 AECOPD diagnosed patients groups and 195 healthy peoples suggested their significant differences of the three genotypes (AA, GA, GG) distribution for TNF-α -308 (P < 0.05), but no differences of that for TNF-α +489. We found that patients with TNF-α -308 GA/AA genotypes showed smaller adjacent arterial diameter, thicker bronchial wall, higher bronchial artery ratio, higher bronchial wall grading, and higher frequency of acute exacerbations than those with TNF-α -308 GG genotype. Patients with TNF-α +489 GA/AA genotypes showed the same AECOPD properties as patients with TNF-α -308 except for the high frequency of acute exacerbations. Further experiment showed that the TNF-α -308 and+489 gene polymorphisms could affect the expression level of TNF-α in macrophages, suggesting the involvement of the macrophage population in disease regulation of AECOPD patients with TNF-α -308G/A and+489G/A genotype heterogeneity. In conclusion, the TNF-α -308 G/A genotype was related to AECOPD susceptibility and progress, while the TNF-α +489G/A genotype was related to AECOPD progress, but not AECOPD susceptibility.

Effects of the IL6 -174G>C promoter polymorphism and IL-6 serum levels on the progression of cutaneous malignant melanoma

Cutaneous malignant melanoma (CMM) is one of the most immunogenic types of cancer, with a 6-fold higher rate of spontaneous regression than any other malignancy. In addition to responsiveness to different immunotherapies, the immunogenicity of CMM highlights the important role of the host immune system in the response to CMM. The present study aimed to explore the role of two functional promoter polymorphisms [IL6 -174G>C (rs1800785) and TNFA -308G>A (rs1800629)] in the regulation of the genes encoding the pro-inflammatory cytokines interleukin (IL)-6 and tumor necrosis factor-α, specifically in patients with CMM. A total of 76 patients with CMM and 200 control subjects were genotyped using PCR-restriction fragment length polymorphism. The genotype frequencies for both single nucleotide polymorphisms (SNPs) did not differ significantly between the patients and controls (P=0.358 and P=0.810 for IL6 and TNFA, respectively). However, compared with carriers of C-allele genotypes (CG+CC), patients with the IL6 -174GG genotype exhibited more advanced melanoma (Clark scale ≥3; P=0.037) and shorter survival times, particularly those who worked outdoors (in conditions with increased sunlight exposure; P=0.016). Furthermore, the serum IL-6 levels of patients with CMM were significantly higher than those of the control subjects, which were associated with unfavorable blood and serum characteristics and tumor progression (development of new distant metastases; P=0.004), and with a shorter overall survival time (P=0.042). Using a Cox proportional hazard model, the IL6 -174GG genotype was found to be an independent prognostic factor for reduced survival time (P=0.030), together with sex (being male; P=0.004) and occupations with higher exposure to sunlight (P=0.047). In conclusion, the results of the present study indicated that the promoter polymorphisms IL6 -174G>C and TNFA -308G>A are not predisposing factors for CMM. However, the IL6 -174G>C SNP and IL-6 serum concentrations are likely to influence the progression of the disease, and the GG genotype and higher IL-6 serum levels may indicate shorter survival.

TNF-α -308 G/A variant and susceptibility to chronic obstructive pulmonary disease: A systematic review and meta-analysis

BACKGROUND AND OBJECTIVE

TNF-α -308 G/A variant is recognized to play an important role in the pathogenesis of chronic obstructive pulmonary disease (COPD). Although many studies have investigated the association of TNF-α-308 and COPD risk, a deep understanding of this association is lacking due to small subjects sizes and insufficiently study designs among different investigations. In this study, a systematic review and meta-analysis was performed based on published reports on the association of TNF-α and COPD.

METHOD

The published studies concerned the association between TNF-α and COPD were identified using a systematic research in Scopus, Google Scholar, and PubMed up to April 2018. A total of 46 different papers studying the rs1800629 variant in TNF-α gene were included. Then, human studies were selected to further analysis regardless of papers language.

RESULTS

Based on the results, the major outcome of this meta-analysis can be represented as follows: individuals with GG and GA genotypes possess less risk of developing COPD (OR = 0.58, 95%CI: (0.44-0.79), P < 0.00) compared to AA genotype carriers. In contrast, the AA genotype carriers of the TNF-α rs1800629 has a significantly higher risk of developing COPD (OR = 1.83, 95%CI: (1.34-2.51), P < 0.00) compared to GG carrier. Despite the previous meta-analysis results which reported significantly decreasing of heterogeneity with ethnicity, we found that the source of controls has a significant contribution to observed heterogeneity.

CONCLUSIONS

Thanks to the global burden of COPD studies, proving TNF-α 308 gene variant as an independent factor in its pathogenesis opens new insights to diagnosis and management of COPD.

TNF promoter polymorphisms are associated with genetic susceptibility in COPD secondary to tobacco smoking and biomass burning

Background

Smoking and smoke from biomass burning (BB) are the main environmental risk factors for COPD. Clinical differences have been described between COPD related to smoking and related to wood smoke, but no studies have shown genetic differences between patients exposed to these two risk factors.

Methods

To investigate a possible association of tumor necrosis factor (TNF) promoter polymorphisms, we conducted a case–control study. A total of 1,322 subjects were included in four groups: patients with a diagnosis of COPD secondary to smoking (COPD-S, n=384), patients with COPD secondary to biomass burning (COPD-BB, n=168), smokers without COPD (SWOC, n=674), and biomass burning-exposed subjects (BBES n=96). Additionally, a group of 950 Mexican mestizos (MMs) was included as a population control. Three single nucleotide polymorphisms (SNPs) were selected in the TNF gene (rs1800629, rs361525, and rs1800750) and one SNP in the lymphotoxin alpha gene (rs909253).

Results

Statistically significant differences were found with genotype GA of the rs1800629: COPD-S vs SWOC, (p<0.001, odds ratio [OR] =2.55, 95% CI=1.53–4.27); COPD-S vs COPD-BB (p,0.01). When performing the comparison of the less severe (G1: I + II) and the more severe (G2: III + IV) levels, differences were identified in G1 (p<0.05, OR=1.94, 95% CI=1.04–3.63) and G2 (p<0.001, OR=3.68, 95% CI=1.94–3.07) compared with SWOC. Regarding genotype GA of rs361525, it has been associated when comparing COPD-BB vs BBES (p=0.0079, OR=5.99, 95% CI=1.38–53.98).

Conclusion

The heterozygous genotype GA of polymorphisms rs1800629 and rs361525 in the TNF promoter are associated with the risk of COPD.

Association between TNF-α -308 G/A polymorphism and COPD susceptibility: a meta-analysis update

Background and objective

The association between TNF-α −308 G/A polymorphism and COPD remains controversial due to insufficiently strict study designs and small group sizes among different studies. In the present study, a meta-analysis update which followed a stricter procedure was performed to obtain a clearer understanding of this association.

Methods

A comprehensive database search was conducted to identify the case–control studies published up to July 2015 which reported an association between the TNF-α −308 G/A polymorphism and COPD risk. Data were extracted to calculate pooled odds ratios with 95% confidence intervals under the most appropriate genetic and allelic models. Sensitivity was analyzed, and heterogeneity as well as publication bias was assessed.

Results

Thirty-eight eligible studies, comprising 3,951 COPD cases and 5,110 controls, were included in this study, among which 22 studies comprising 2,067 COPD cases and 2,167 controls were performed in Asians, and 16 studies comprising 1,884 COPD cases and 2,943 controls were in non-Asians. The overall result showed that TNF-α −308 G/A polymorphisms were significantly associated with increased COPD risk in both the codominant genetic and allelic models. Individuals with the GA or AA genotype were more susceptible to COPD development than those with the GG genotype. In addition, individuals with the AA genotype were more susceptible to developing COPD than those with the GA genotype. The subgroup analysis stratified by ethnicity supported the results in Asians but not in non-Asians. However, no association was found between TNF-α −308 G/A polymorphisms and COPD susceptibility either in Asians or in non-Asians in the meta-analysis conducted with restriction to former/current smokers.

Conclusion

The present meta-analysis suggested that the TNF-α −308 G/A polymorphism was associated with an increased risk of COPD among Asians but not in non-Asians. Furthermore, individuals with the AA genotype of TNF-α −308 were more susceptible to developing COPD.

Identification of genetic variants in the TNF promoter associated with COPD secondary to tobacco smoking and its severity

Chronic obstructive pulmonary disease (COPD) is an inflammatory disease that arises in response to noxious particles or gases. Associations of genetic polymorphisms in TNF have been reported in Asians and Caucasians, but not in Mestizo populations. A case-control study was conducted in two stages: in the first stage, patients with COPD (COPD group, n=165) and smokers without disease (SNC group, n=165) were included and the TNF promoter sequence was determined using direct sequencing. In the second stage, the identified polymorphisms were validated by real-time polymerase chain reaction (PCR) in COPD (n=260) and SNC (n=506). In the first stage, 11 different sets of “contig” alignments were determined, of which contig 10 was found to be associated with susceptibility (P=5.0E-04, OR [odds ratio] =3.64) and contig 1 with Global Initiative for COPD (GOLD) greater grade (P=1.0E-02, OR =3.82). The single nucleotide polymorphisms found in this region were individually identified; the GA genotypes of rs1800629 (P=0.038, OR =2.07), rs56036015 (P=0.0082, OR =3.18), and rs361525 (P=1.0E-02, OR =4.220) were higher in the COPD group vs the SNC group; after second-stage validation, rs1800629 (P=6.00E-03, OR =2.26) and rs56036015 (P=1.10E-03, OR =2.54) are maintained. There are genetic variants in the TNF promoter associated with increased risk of COPD secondary to smoking and with a higher GOLD grade in the Mexican Mestizo population.

Association of genes of protease-antiprotease balance pathway to lung function and emphysema subtypes

Background

The imbalance between proteases and antiproteases has been proposed to participate to the pathogenesis of chronic obstructive pulmonary disease (COPD) and emphysema. Gene level variation in different metalloproteinases, metalloproteinase inhibitors, and cytokines affecting them may contribute to this imbalance and destruction of the lung parenchyma. We investigated whether polymorphisms in selected protease-antiprotease balance pathway genes predispose to different emphysema subtypes (centrilobular, paraseptal, panlobular, and bullae) and airflow limitation among Finnish construction workers.

Methods

Eleven single nucleotide polymorphisms (SNPs) from seven genes (GC: rs7041 and rs4588; MMP1: rs1799750; MMP9: rs3918242; MMP12: rs652438; TIMP2: rs2277698; TNF: rs1799724 and rs1800629; TGFB1: rs1800469, rs1800470, and rs2241718) were analyzed from 951 clinically and radiologically characterized construction workers. The genotype and haplotype data was compared to different emphysematous signs confirmed with high resolution computed tomography (HRCT), forced vital capacity (FVC), forced expiratory volume in one second (FEV₁), and maximal expiratory flow at 50% of FVC (MEF50) by using linear and logistic regression analyses, adjusted for potential confounders.

Results

The TIMP2 rs2277698 SNP was associated with overall (p = 0.022) and paraseptal (p = 0.010) emphysema, as well as with FEV₁/FVC ratio (p = 0.035) and MEF50 (p = 0.008). The TGFB1 rs2241718 and MMP9 rs3918242 SNPs were associated with centrilobular emphysema (p = 0.022 and p = 0.008), and the TNF rs1800629 SNP with paraseptal emphysema (p = 0.017). In stratified analysis, individuals with at least one TIMP2 rs2277698 or TNF rs1800629 variant allele were found to be at around two-fold risk for pathological paraseptal changes (OR 1.94, 95% CI 1.14-3.30; OR 2.10, 95% CI 1.24-3.56). On the contrary, the risk for pathological centrilobular changes was halved for individuals with at least one MMP9 rs3918242 (OR 0.51, 95% CI 0.30-0.86) or TGFB1 rs2241718 (OR 0.53, 95% CI 0.30-0.90) variant allele, or TGFB1 rs1800469-rs1800470 AT-haplotype (OR 0.55, 95% CI 0.33-0.93). MEF50, in turn, was significantly reduced among individuals with at least one TIMP2 rs2277698 variant allele (p = 0.011).

Conclusion

Our findings strengthen the hypothesis of the importance of protease-antiprotease balance in pathogenesis of emphysema and shed light on the aetiology of different emphysema subtypes by associating MMP9 and TGFB1 to centrilobular emphysema, and TIMP2 and TNF to paraseptal emphysema and/or airflow obstruction.

Updates on the COPD gene list

A genetic contribution to develop chronic obstructive pulmonary disease (COPD) is well established. However, the specific genes responsible for enhanced risk or host differences in susceptibility to smoke exposure remain poorly understood. The goal of this review is to provide a comprehensive literature overview on the genetics of COPD, highlight the most promising findings during the last few years, and ultimately provide an updated COPD gene list. Candidate gene studies on COPD and related phenotypes indexed in PubMed before January 5, 2012 are tabulated. An exhaustive list of publications for any given gene was looked for. This well-documented COPD candidate-gene list is expected to serve many purposes for future replication studies and meta-analyses as well as for reanalyzing collected genomic data in the field. In addition, this review summarizes recent genetic loci identified by genome-wide association studies on COPD, lung function, and related complications. Assembling resources, integrative genomic approaches, and large sample sizes of well-phenotyped subjects is part of the path forward to elucidate the genetic basis of this debilitating disease.

Inflammation, chronic obstructive pulmonary disease and aging

PURPOSE OF REVIEW

Chronic obstructive pulmonary disease (COPD) is characterized by an abnormal persistent inflammatory response to noxious environmental stimuli, particularly cigarette smoke. The determinants of the dysregulated immune responses, which play a role both in the onset and continuation of COPD, are largely unknown. We examined several molecular mechanisms regulating the inflammatory pathway, such as cytokine polymorphisms, miRNA expression, and DNA methylation in COPD and aging, with the aim to provide evidence supporting the view that aging of the immune system may predispose to COPD.

RECENT FINDINGS

The incidence of COPD increases with age. The pathogenesis of the disease is linked to a chronic inflammation and involves the recruitment and regulation of innate and adaptive immune cells. A chronic systemic inflammation characterizes aging and has been correlated with many diseases, most of them age-related.

SUMMARY

COPD and aging are associated with significant dysregulation of the immune system that leads to a chronic inflammatory response. The similar molecular mechanisms and the common genetic signature shared by COPD and aging suggest that immunosenescence may contribute to the development of COPD.

Association between vitamin D receptor gene polymorphisms and bone mineral density in Chinese women

Vitamin D receptor (VDR) is implicated in the regulation of bone mineral density (BMD). In this study, we performed a meta-analysis to evaluate the association between the VDR BsmI (rs1544410) and ApaI (rs7975232) polymorphisms and BMD in Chinese women. Literature was retrieved from PubMed and other databases. The studies on the association between VDR BsmI and ApaI genotypes and BMD at the lumbar spine, the femoral neck, the trochanter or the Ward's triangle in Han Chinese women were included in this meta-analysis. Pooled BMD differences and 95% confidence intervals (CIs) were calculated using random- or fixed- effects model. Twenty-five eligible studies, which included 4,075 Chinese women, were identified. No significant difference was observed for either genotype when the meta-analysis was limited to premenopausal women. In postmenopausal women, BMD differences were significant for BB vs. Bb [-0.029 (95% CI -0.056, -0.002) g/m(2), P = 0.037] at the femoral neck, AA vs. Aa [-0.029 (95% CI -0.051, -0.006) g/m(2), P = 0.012] at the lumbar spine, and Aa vs. aa [0.022(95% CI 0.011, 0.033) g/m(2), P = 0.000] at the trochanter. These results suggest a modest but statistically significant association between VDR BsmI and ApaI polymorphisms and BMD in Chinese postmenopausal women, with higher BMD in heterozygous subjects. More epidemiological and mechanistic studies are needed to further investigate the role of VDR gene polymorphisms in regulating BMD and osteoporosis in the future.

GABBR1 gene polymorphism(G1465A)isassociated with temporal lobe epilepsy

PURPOSE

γ-Aminobutyric acid B receptor 1(GABBR1) gene G1465A polymorphism has been considered as a potential risk factor for the development of temporal lobe epilepsy (TLE). However, the results were inconsistent. In this study, we performed a meta-analysis to assess the association between GABBR1 G1465A polymorphism and the risk of TLE.

METHODS

Biomedical literature databases including PubMed, ISI web of science and Embase were searched. The studies evaluating the association between GABBR1 G1465A polymorphism and TLE were included. Pooled odds ratio (OR) and 95%CI confidence interval (CI) were calculated using fixed- or random-effects model.

KEY FINDINGS

Seven studies (1011 cases and 2184 controls) met the inclusion criteria and were included in the meta-analysis. The overall result showed that the association between GABBR1 G1465A polymorphism was statistically significant (OR=5.381, 95%CI: 1.726, 16.776, P=0.004). Subgroup analysis showed that the effect estimate was higher in the studies with high quality score (OR=14.220, 95%CI: 6.933, 29.169, P=0.000) than that in the studies with low quality score (OR=1.158, 95%CI: 0.325, 4.123, P=0.821).

SIGNIFICANCE

The present meta-analysis suggests that GABBR1 G1465A polymorphism is associated with the risk of TLE. The role of GABBR1 G1465A polymorphism in the development of TLE merits further investigation.

Association of the CYP3A5 polymorphism (6986G>A) with blood pressure and hypertension

The cytochrome P450 family 3 subfamily A polypeptide 5 (CYP3A5) gene has been implicated in the regulation of blood pressure (BP) and thus, may serve as a potential risk factor for the development of hypertension. However, current results regarding the association between CYP3A5 single nucleotide polymorphisms and BP/hypertension have been inconsistent. In this study, we performed a meta-analysis to evaluate the association between the CYP3A5 rs776746 (6986G>A) polymorphism and BP/hypertension. Ten studies (representing 2799 cases and 6794 controls) were included to determine the association of this single nucleotide polymorphism with hypertension, and 12 studies (9076 subjects) were included to determine the association of this single nucleotide polymorphism with BP. Overall, no associations were observed between the rs776746 polymorphism and BP/hypertension. In subgroup analysis, CYP3A5*1 carriers had lower systolic BP, compared with non-carriers in white populations (mean difference=-1.322, 95% confidence interval -2.401 to -0.242 mm Hg, P=0.016). This meta-analysis suggested a modestly significant association between the CYP3A5 rs776746 polymorphism and systolic BP in white populations. Given the limited sample size, additional studies are necessary to investigate the role of CYP3A5 in the regulation of BP and the pathogenesis of hypertension.

GST polymorphisms are associated with hepatocellular carcinoma risk in Chinese population

AIM: To investigate the association between GSTM1 and GSTT1 polymorphisms and the risk of hepatocellular carcinoma (HCC) in Chinese population.

METHODS: Literature databases including PubMed, ISI web of science and other databases were searched. Pooled odds ratio (OR) and 95% CI were calculated using random- or fixed- effects model. Subgroup analysis and sensitivity analysis were also performed.

RESULTS: Nineteen studies of GSTM1 (2660 cases and 4017 controls) and 16 studies of GSTT1 (2410 cases and 3669 controls) were included. The GSTM1/GSTT1 null genotypes were associated with increased risk of HCC in Chinese population (for GSTM1, OR = 1.487, 95% CI: 1.159 to 1.908, P = 0.002; for GSTT1, OR = 1.510, 95% CI: 1.236 to 1.845, P = 0.000). No publication bias was detected. In subgroup analysis, glutathione S-transferases polymorphisms were significantly associated with HCC risk among the subjects living in high-incidence areas, but not among the subjects living in low-incidence areas.

CONCLUSION: The present meta-analysis suggests that GSTM1/GSTT1 null genotypes are associated with increased risk of HCC in Chinese population.