Association of genetic polymorphisms with chronic obstructive pulmonary disease in the Chinese Han population: a case-control study

sRAGE levels are decreased in plasma and sputum of COPD secondary to biomass-burning smoke and tobacco smoking: Differences according to the rs3134940 AGER variant

The receptor for advanced glycation end products (RAGE) and its gene (AGER) have been related to lung injury and inflammatory diseases, including chronic obstructive pulmonary disease (COPD). We aimed to evaluate the association of rs2071288, rs3134940, rs184003, and rs2070600 AGER single-nucleotide variants and the soluble-RAGE plasma and sputum levels with COPD secondary to biomass-burning smoke (BBS) and tobacco smoking. Four groups, including 2189 subjects, were analyzed: COPD secondary to BBS exposure (COPD-BBS, n = 342), BBS-exposed subjects without COPD (BBES, n = 774), tobacco smoking-induced COPD (COPD-TS, n = 434), and smokers without COPD (SWOC, n = 639). Allelic discrimination assays determined the AGER variants. The sRAGE was quantified in plasma (n = 240) and induced-sputum (n = 72) samples from a subgroup of patients using the ELISA technique. In addition, a meta-analysis was performed for the association of rs2070600 with COPD susceptibility. None of the studied genetic variants were found to be associated with COPD-BBS or COPD-TS. A marginal association was observed for the rs3134940 with COPD-BBS (p = 0.066). The results from the meta-analysis, including six case-control studies (n = 4149 subjects), showed a lack of association of rs2070600 with COPD susceptibility (p = 0.681), probably due to interethnic differences. The sRAGE plasma levels were lower in COPD-BBS compared to BBS and in COPD-TS compared to SWOC. The sRAGE levels were also lower in sputum samples from COPD-BBS than BBES. Subjects with rs3134940-TC genotypes exhibit lower sRAGE plasma levels than TT subjects, mainly from the COPD-BBS and SWOC groups. The AGER variants were not associated with COPD-BBS nor COPD-TS, but the sRAGE plasma and sputum levels are related to both COPD-BBS and COPD-TS and are influenced by the rs3134940 variant.

Association between single-nucleotide polymorphism of cytokines genes and chronic obstructive pulmonary disease: A systematic review and meta-analysis

Chronic obstructive pulmonary disease (COPD) is a common chronic inflammatory disease with high morbidity and mortality rates worldwide. Cytokines, which are the main regulators of immune responses, play crucial roles in inflammatory diseases such as COPD. Moreover, certain genetic variations can alter cytokine expression, and changes in cytokine level or function can affect disease susceptibility. Therefore, investigating the association between genetic variations and disease progression can be useful for prevention and treatment. Several studies have explored the association between common genetic variations in cytokine genes and COPD susceptibility. In this study, we summarized the reported studies and, where possible, conducted a systematic review and meta-analysis to evaluate the genetic association between various cytokines and COPD pathogenesis. We extracted relevant articles from PubMed and Google Scholar databases using a standard systematic search strategy. We included a total of 183 studies from 78 separate articles that evaluated 50 polymorphisms in 12 cytokine genes in this study. Our analysis showed that among all reported cytokine polymorphisms (including TNF-α, TGF-β, IL1, IL1RN, IL4, IL4R, IL6, IL10, IL12, IL13, IL17, IL18, IL27, and IL33), only four variants, including TNF-α-rs1800629, TGF-β1-rs6957, IL13-rs1800925, and IL6-rs1800796, were associated with the risk of COPD development. This updated meta-analysis strongly supports the association of TNF-α-rs1800629, TGF-β1-rs6957, IL13-rs1800925, and IL6-rs1800796 variants with a high risk of COPD.

Association of transforming growth factor-β gene polymorphisms and chronic obstructive pulmonary disease risk

Recently, He et al. performed a meta-analysis to interpret the association between transforming growth factor-β (TGF-β) gene polymorphisms and chronic obstructive pulmonary disease (COPD) risk. However, we would like to comment on some debatable points shown in this meta-analysis.

Hedgehog signaling modulates cigarette-induced COPD development

Hedgehog (Hh) signaling is involved in early embryogenesis and maintains quiescence in the adult lungs. The interruption of Hh signaling may lead to the development of chronic obstructive pulmonary disease (COPD). The current study aimed to assess whether the Hh pathway affects cigarette-induced emphysema and airway inflammation by regulating inflammatory cytokines. C57BL/6J mice were randomized into control, cigarette smoke (CS) or CS + cyclopamine (CSC) groups. Control mice were exposed to normal room air, CS mice were exposed to tobacco smoke and CSC mice were exposed to CS and received cyclopamine treatment. Histopathological examination of lung tissues was performed, and the expression of sonic hedgehog (HH), glioma-associated oncogene homolog 1 (Gli1), hedgehog-interacting protein (HIP) and several inflammatory mediators (intracellular adhesion molecule-1, IL-6, IL-8 and TNF-α) were compared using reverse transcription-quantitative PCR and western blotting. The emphysema of lung tissues by histopathological examination demonstrated partial amelioration in the CSC group compared with that in the CS group. Additionally, expression levels of SHH, Gli1 and inflammatory mediators were significantly higher in the CS group compared with the control group but were significantly decreased in the CSC group. The expression of HIP was decreased in the CS group, but significantly increased in the CSC group. Hh signaling may serve an important role in cigarette-induced emphysema and airway inflammation by regulating inflammatory cytokines in animal models. Therefore, diminishing the activation of the Hh signal may serve as a novel therapeutic strategy for patients suffering from smoking-related COPD.

The AGE-RAGE Axis and RAGE Genetics in Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) is a heterogeneous group of lung diseases limiting the airflow due to narrowing of airways, chronic bronchitis and emphysema that leads to difficulties in breathing. Chronic inflammation is another important characteristic of COPD which leads to immune cell infiltration and helps in the alveolar destruction. Pathology of COPD is driven by various environmental and genetic factors. COPD is mainly associated with the inhalation of toxic agents mainly the cigarette smoke. Receptor for advanced glycation end products (RAGE) has emerged as a pattern recognition receptor and is a multiligand receptor expressed moderately in various cells, tissues and highly in the lungs throughout life. RAGE recognizes various ligands produced by cigarette smoke and its role has been implicated in the pathogenesis of COPD. RAGE ligands have been reported to accumulate in the lungs of patients with COPD. RAGE is a membrane receptor but its truncated form i.e. soluble RAGE (sRAGE) mainly functions as a contender of RAGE and inhibits various RAGE dependent cell signalling. Among the various ligands of RAGE, advanced glycation end products (AGEs) are majorly linked with COPD. Accumulated AGE triggers downstream RAGE-AGE axis in COPD. Moreover, RAGE genetics has long been known to play a vital role in the pathology of various airway diseases including COPD and this gene contains an associated locus. A reliable biomarker is needed for the management of this disease. sRAGE has an inverse correlation with the RAGE showed its importance as a valuable marker in COPD. This review is focused on the role of RAGE, sRAGE, RAGE axis and RAGE genetics in COPD.

Association of RAGE gene multiple variants with the risk for COPD and asthma in northern Han Chinese

Clinical and experimental data have shown that the receptor for advanced glycation end products (RAGE) is implicated in the pathogenesis of respiratory disorders. In this study, we genotyped five widely-evaluated variants in RAGE gene, aiming to assess their association with the risk for chronic obstructive pulmonary disease (COPD) and asthma in northern Han Chinese. Genotypes were determined in 105 COPD patients, 242 asthma patients and 527 controls. In single-locus analysis, there was significant difference in the genotype distributions of rs1800624 between COPD patients and controls (p=0.022), and the genotype and allele distributions of rs1800625 differed significantly (p=0.040 and 0.016) between asthma patients and controls. Haplotype analysis revealed that haplotype T-A-G-T (allele order: rs1800625, rs1800624, rs2070600, rs184003) was significantly associated with a reduced COPD risk (OR=0.32, 95% CI: 0.06-0.60), and haplotype T-A-A-G was significantly associated with a reduced asthma risk (OR=0.19, 95% CI: 0.04-0.96). Further haplotype-phenotype analysis showed that high- and low-density lipoprotein cholesterol and blood urea nitrogen were significant mediators for COPD (p_sim=0.041, 0.043 and 0.030, respectively), and total cholesterol was a significant mediator for asthma (p_sim=0.009). Taken together, our findings indicate that RAGE gene is a promising candidate for COPD and asthma, and importantly both disorders are genetically heterogeneous.

Comparison and development of machine learning tools for the prediction of chronic obstructive pulmonary disease in the Chinese population

Background

Chronic obstructive pulmonary disease (COPD) is a major public health problem and cause of mortality worldwide. However, COPD in the early stage is usually not recognized and diagnosed. It is necessary to establish a risk model to predict COPD development.

Methods

A total of 441 COPD patients and 192 control subjects were recruited, and 101 single-nucleotide polymorphisms (SNPs) were determined using the MassArray assay. With 5 clinical features as well as SNPs, 6 predictive models were established and evaluated in the training set and test set by the confusion matrix AU-ROC, AU-PRC, sensitivity (recall), specificity, accuracy, F1 score, MCC, PPV (precision) and NPV. The selected features were ranked.

Results

Nine SNPs were significantly associated with COPD. Among them, 6 SNPs (rs1007052, OR = 1.671, P = 0.010; rs2910164, OR = 1.416, P < 0.037; rs473892, OR = 1.473, P < 0.044; rs161976, OR = 1.594, P < 0.044; rs159497, OR = 1.445, P < 0.045; and rs9296092, OR = 1.832, P < 0.045) were risk factors for COPD, while 3 SNPs (rs8192288, OR = 0.593, P < 0.015; rs20541, OR = 0.669, P < 0.018; and rs12922394, OR = 0.651, P < 0.022) were protective factors for COPD development. In the training set, KNN, LR, SVM, DT and XGboost obtained AU-ROC values above 0.82 and AU-PRC values above 0.92. Among these models, XGboost obtained the highest AU-ROC (0.94), AU-PRC (0.97), accuracy (0.91), precision (0.95), F1 score (0.94), MCC (0.77) and specificity (0.85), while MLP obtained the highest sensitivity (recall) (0.99) and NPV (0.87). In the validation set, KNN, LR and XGboost obtained AU-ROC and AU-PRC values above 0.80 and 0.85, respectively. KNN had the highest precision (0.82), both KNN and LR obtained the same highest accuracy (0.81), and KNN and LR had the same highest F1 score (0.86). Both DT and MLP obtained sensitivity (recall) and NPV values above 0.94 and 0.84, respectively. In the feature importance analyses, we identified that AQCI, age, and BMI had the greatest impact on the predictive abilities of the models, while SNPs, sex and smoking were less important.

Conclusions

The KNN, LR and XGboost models showed excellent overall predictive power, and the use of machine learning tools combining both clinical and SNP features was suitable for predicting the risk of COPD development.

A correlational meta-analytical study of transforming growth factor-β genetic polymorphisms as a risk factor for chronic obstructive pulmonary disease

BACKGROUND

Several studies have examined the association between transforming growth factor-β (TGF-β) genetic polymorphisms and chronic obstructive pulmonary disease (COPD) risk, but the results remained inconclusive and controversial.

AIMS

We aimed to examine the correlation between TGF-β genetic polymorphisms and COPD risk through a comprehensive meta-analysis. Additionally, changes in circulating TGF-β concentrations across genotypes of TGF-β genetic polymorphisms were analyzed.

METHODS

Literature search, quality assessment, and data extraction were completed independently and in duplicate. Data are expressed in odds ratio (OR) or weighted mean difference (WMD) with 95% confidence interval (CI).

RESULTS

A total of 12 articles, involving 14 independent studies and 7 170 participants, were meta-analyzed for the correlation of five polymorphisms (rs2241712, rs1800469, rs1982073, rs6957, and rs2241718) in TGF-β gene with COPD risk. Under the allele model, no statistical significance was observed for all polymorphisms associated with COPD risk. Subsidiary analyses indicated that country, COPD stage, and diagnosis of COPD were potential sources of between-study heterogeneity. Filled full plots revealed no missing studies for all studied polymorphisms, except rs1982073. Genotype-phenotype analyses showed that carriers of rs1800469 CT genotype had significantly higher concentrations of circulating TGF-β than those with CC genotype in COPD patients (WMD: 0.28 pg/ml, 95% CI: 0.01 to 0.56).

CONCLUSION

Our findings failed to support the candidacy of TGF-β gene in the development of COPD, whereas the contribution of TGF-β gene to COPD might be ethnicity- and stage-dependent.

Interleukin-6 serum level and -597 A/G gene polymorphism in moderate and severe chronic obstructive pulmonary disease

Inflammation is a major pathogenic pathway in pulmonary chronic obstructive disease (COPD). Interleukin-6 (IL-6) mediates the local and systemic immune response. The aim consisted in investigating the relationship between IL-6 serum levels and IL-6 -597A/G gene polymorphism (rs1800797) with COPD. Serum levels of IL-6 were determined using an enzyme-linked immune-sorbent assay, in 120 participants (60 COPD patients and 60 healthy subjects), from Transylvanian region. The IL-6 -597A/G gene polymorphism was investigated by high molecular weight genomic DNA extracted from the peripheral blood leukocytes, and subsequently analyzed by the Polymerase Chain Reaction Restriction Fragment Length Polymorphism (PCR-RFLP) technique. Smoking history, the severity of the disease, expressed by the GOLD stages, and arterial blood partial pressure of oxygen (PaO2) levels were also investigated. COPD patients had significantly elevated blood levels of IL-6 when compared to the control group ( p < 0.05). The frequencies of AA, AG, and GG genotypes were 61.6%, 26.6%, and 11.6% in the COPD cases and 70%, 23.3%, and 6.7% in healthy subjects, respectively. There were no statistically significant differences in IL-6 rs1800797 genotypes and allele frequencies between cases and controls ( χ2 = 0.54, OR = 1.29 and χ2 = 0.21, OR = 1.48, respectively). Higher serum levels of IL-6 were found in the GG genotype subgroup in COPD patients. IL 6 levels are higher in COPD patients, where positively correlate with pack-year index, but not with clinical features. Although COPD patients did not have statistically different rs1800797 allele distribution compared to healthy subjects, the GG genotype is associated with higher IL6 serum levels.

Three SNPs of FCRL3 and one SNP of MTMR3 are associated with immunoglobulin A nephropathy risk

PURPOSE

Immunoglobulin A nephropathy (IgAN) is determined by a combination of multiple genetic and environmental factors, but its etiology and pathogenesis are not well understood. We aim to determine whether variations in FCRL3 and MTMR3 correlate with IgAN risk indices in Chinese Han people.

METHODS

Eight single nucleotide polymorphisms (SNPs) of FCRL3 and MTMR3 were genotyped, and association analysis was performed. A total of 426 patients with IgAN and 498 healthy individuals, serving as the control group, were recruited for this association study.

RESULTS

There were significant associations between FCRL3 rs11264793 (OR = 0.78; 95 % CI = 0.63-0.98; p = 0.029), rs11264794 (OR = 0.81; 95 % CI = 0.67-0.98; p = 0.026) and rs7522061 (OR = 0.79; 95 % CI = 0.65-0.95; p = 0.012) and decreased risk of IgAN according to allele model results. Under genetic models, FCRL3 and MTMR3 were associated with the risk of IgAN. Interestingly, FCRL3 reduced the IgAN susceptibility only in females, while MTMR3 was a risk factor for IgAN only in males. In addition, FCRL3 rs11264793 and rs7522061 were significantly associated with a decreased risk of IgAN in different disease grades. Moreover, the haplotypes ACC (p = 0.02) and CTC (p = 0.017) of LD block rs11264794/rs7522061/rs11264799 in the FCRL3 gene were significantly associated with a decreased risk of IgAN.

CONCLUSIONS

We suggest that three SNPs of FCRL3 were associated with a decreased risk of IgAN, while one SNP of MTMR3 was associated with an increased risk of IgAN in Chinese Han populations. These findings may be useful in the development of early prognostics for IgAN.

Genetic underpinnings of lung function and COPD

Spirometry based measurement of lung function is a global initiative for chronic obstructive lung disease (GOLD) standard to diagnose chronic obstructive pulmonary disease (COPD), one of the leading causes of mortality worldwide. The environmental and behavioural risk factors for COPD includes tobacco smoking, air pollutants and biomass fuel exposure, which can induce one or more abnormal lung function patterns. While smoking remains the primary risk factor, only 15-20% smokers develop COPD, indicating that the genetic factors are also likely to play a role. According to the study of Global Burden of Disease 2015, ∼174 million people across the world have COPD. From a comprehensive literature search conducted using the 'PubMed' and 'GWAS Catalogue' databases, and reviewing the literature available, only a limited number of studies were identified which had attempted to investigate the genetics of COPD and lung volumes, implying a huge research gap. With the advent of genomewide association studies several genetic variants linked to lung function and COPD, like HHIP, HTR4, ADAM19 and GSTCD etc., have been found and validated in different population groups, suggesting their potential role in determining lung volume and risk for COPD. This article aims at reviewing the present knowledge of the genetics of lung function and COPD.

Association between chronic obstructive pulmonary disease and interleukins gene variants: A systematic review and meta-analysis

Interleukins are cytokines involved in systemic inflammation and immune system regulation. Many studies have investigated the association between common genetic variations in interleukin-coding genes and COPD susceptibility. In this study, a systematic review and meta-analysis was performed to evaluate the association between interleukin gene variations and COPD pathogenesis. Association studies were retrieved from PubMed and Google Scholar databases using the standard systematic search strategy. A total of 26 different studies evaluating eight polymorphisms in four interleukin genes were included in this study. In overall comparisons, IL1β-rs16944, -rs1143627, -rs1143634, IL13-rs20541 polymorphisms were found not to be associated with the increased risk for developing COPD. However, IL1RN-rs2234663 and IL13-rs1800925 showed a strong association with COPD. We showed that the CC genotype carriers of the IL6-rs1800795 are at significantly higher risk of developing COPD (OR = 1.31, 95% CI: 1.04-1.64, P = 0.01) compared to GG carriers. In case of IL6-rs1800796, individuals with CC and CG genotypes showed a lower risk to develop COPD (OR = 0.46, 95%CI: 0.32-0.66, P > 0.00). This updated meta-analysis strongly supports the association of IL1RN-rs2234663, IL6-rs1800795, -rs1800795 and IL13-rs1800925 variants with COPD.

Pathological Implications of Receptor for Advanced Glycation End-Product (AGER) Gene Polymorphism

The receptor for advanced glycation end-products (RAGE) is a cell surface transmembrane multiligand receptor, encoded by the AGER gene. RAGE presents many transcripts, is expressed mainly in the lung, and involves multiple pathways (such as NFκB, Akt, p38, and MAP kinases) that initiate and perpetuate an unfavorable proinflammatory state. Due to these numerous functional activities, RAGE is implicated in multiple diseases. AGER is a highly polymorphic gene, with polymorphisms or SNP (single-nucleotide polymorphism) that could be responsible or co-responsible for disease development. This review was designed to shed light on the pathological implications of AGER polymorphisms. Five polymorphisms are described: rs2070600, rs1800624, rs1800625, rs184003, and a 63 bp deletion. The rs2070600 SNP may be associated with the development of human autoimmune disease, diabetes complications, cancer, and lung diseases such as chronic obstructive pulmonary disease and acute respiratory distress syndrome. The rs1800624 SNP involves AGER gene regulation and may be related to reduced risk of heart disease, cancer, Crohn's disease, and type 1 diabetes complications. The rs1800625 SNP may be associated with the development of diabetic retinopathy, cancer, and lupus but may be protective against cardiovascular risk. The rs184003 SNP seems related to coronary artery disease, breast cancer, and diabetes. The 63 bp deletion may be associated with reduced survival from heart diseases during diabetic nephropathy. Here, these potential associations between AGER polymorphisms and the development of diseases are discussed, as there have been conflicting findings on the pathological impact of AGER SNPs in the literature. These contradictory results might be explained by distinct AGER SNP frequencies depending on ethnicity.

Association of Surfactant-Associated Protein D Gene Polymorphisms with the Risk of COPD: a Meta-Analysis

The relationship between surfactant-associated protein D polymorphisms and chronic obstructive pulmonary disease risk remains controversial. This article is the first to systematically evaluate this relationship. A comprehensive worldwide search was conducted for relevant literature on surfactant-associated protein D gene mutations and chronic obstructive pulmonary disease risk prediction. Study quality was evaluated using the Newcastle-Ottawa scale. After four genetic models (the allele, additive, recessive, and dominant models) were identified, odds ratios (ORs) and the corresponding 95% confidence intervals (CIs) were applied in this meta-analysis. The meta-analysis included 659 individuals in the case group and 597 in the control group. In the Asian population, none of the four genetic models revealed any significant association between rs2243639 genotype and the risk of chronic obstructive pulmonary disease. In Caucasians, however, the recessive model exhibited significant risk associated with rs2243639. Furthermore, there was a significant association between rs721917 genotype and the risk of chronic obstructive pulmonary disease in the Asian population. In contrast, none of the four gene models revealed any significant risk associated with this gene in the Caucasian population. This meta-analysis suggests that rs2243639 is not related to the risk of chronic obstructive pulmonary disease in the Asian population but is related to this risk in the Caucasian population. Regarding rs721917, the T allele may increase the risk of chronic obstructive pulmonary disease in the Asian population.

Genetic Association of Pulmonary Surfactant Protein Genes, SFTPA1, SFTPA2, SFTPB, SFTPC, and SFTPD With Cystic Fibrosis

Surfactant proteins (SP) are involved in surfactant function and innate immunity in the human lung. Both lung function and innate immunity are altered in CF, and altered SP levels and genetic association are observed in Cystic Fibrosis (CF). We hypothesized that single nucleotide polymorphisms (SNPs) within the SP genes associate with CF or severity subgroups, either through single SNP or via SNP-SNP interactions between two SNPs of a given gene (intragenic) and/or between two genes (intergenic). We genotyped a total of 17 SP SNPs from 72 case-trio pedigree (SFTPA1 (5), SFTPA2 (4), SFTPB (4), SFTPC (2), and SFTPD (2)), and identified SP SNP associations by applying quantitative genetic principles. The results showed (a) Two SNPs, SFTPB rs7316 (p = 0.0083) and SFTPC rs1124 (p = 0.0154), each associated with CF. (b) Three intragenic SNP-SNP interactions, SFTPB (rs2077079, rs3024798), and SFTPA1 (rs1136451, rs1059057 and rs4253527), associated with CF. (c) A total of 34 intergenic SNP-SNP interactions among the 4 SP genes to be associated with CF. (d) No SNP-SNP interaction was observed between SFTPA1 or SFTPA2 and SFTPD. (e) Equal number of SNP-SNP interactions were observed between SFTPB and SFTPA1/SFTPA2 (n = 7) and SP-B and SFTPD (n = 7). (f) SFTPC exhibited significant SNP-SNP interactions with SFTPA1/SFTPA2 (n = 11), SFTPB (n = 4) and SFTPD (n = 3). (g) A single SFTPB SNP was associated with mild CF after Bonferroni correction, and several intergenic interactions that are associated (p < 0.01) with either mild or moderate/severe CF were observed. These collectively indicate that complex SNP-SNP interactions of the SP genes may contribute to the pulmonary disease in CF patients. We speculate that SPs may serve as modifiers for the varied progression of pulmonary disease in CF and/or its severity.

Hedgehog signaling regulates the expression levels of inflammatory mediators in cigarette‑induced airway inflammation

Chronic obstructive pulmonary disease (COPD) is a persistent airway inflammation influenced by cigarette smoke. Previous studies have reported that Hedgehog (Hh) signaling is aberrantly activated by cigarette smoke and dysregulated in COPD. The present study explored the role of the Hh signaling pathway on the expression levels of certain inflammatory mediators in cigarette‑induced airway inflammation. Herein, a total of three A549 cell populations were generated: The A0 group as control cells, the A1 group cells treated with nicotine at a concentration of 10 µM for 12, 24 and 48 h, and the A2 group cultured simultaneously with nicotine and cyclopamine for the same duration. The total concentrations of the inflammatory mediators interleukin‑6 (IL‑6), IL‑8 and tumor necrosis factor (TNF)‑α, and an anti‑inflammatory cytokine, IL‑10, were assessed in all of the cells by ELISA and western blotting. The protein levels of sonic hedgehog (Shh), glioma‑associated oncoprotein 1 (Gli1) and Smoothened (Smo) in nicotine‑induced Hh signaling were also detected. The results indicated that A549 had increased levels of IL‑6, IL‑8 and TNF‑α when cultured with nicotine when compared with the control cells. By contrast, the expression levels of these inflammatory mediators decreased with varying degrees when treated with cyclopamine that blocked the Hh signaling pathway. The IL‑10 expression levels exhibited the reverse. The expressions of the Shh, Gli1 and Smo proteins were higher in the A1 group when compared with the control and decreased with cyclpoamine treatment. In conclusion, the Hh signaling pathway may partly have an impact on cigarette‑induced airway inflammation via the regulation of inflammatory mediators. Thus, blocking Hh signaling and diminishing the airway inflammation reaction may serve as a potential therapy for COPD.

Association of the IL-13 polymorphisms rs1800925 and rs20541 with chronic obstructive pulmonary disease risk: An updated meta-analysis

The aim of this study was to investigate if 2 common single nucleotide polymorphisms (SNPs) in the interleukin-13 (IL-13) gene, rs1800925 and rs20541 are associated with chronic obstructive pulmonary disease (COPD) risk.Case-control association studies were retrieved systematically from PubMed, Scopus, ISI Web of Science, China National Knowledge Infrastructure, and Wanfang databases using standardized subject terms.Eleven studies including 3077 participants (1896 cases and 1181 controls) were analyzed. Evidence for a positive association between the T allele of the IL-13 SNP rs1800925 and COPD risk was found in the overall population (odds ratio [OR] = 1.57, 95% confidence interval [95% CI]: 1.21-2.04, Pz = .001). In subgroup analysis according to ethnicity, the T allele of rs1800925 was associated with an increased risk of COPD in Asians (OR = 1.88, 95% CI: 1.23-2.87, Pz = .004) and Caucasians (OR = 1.30, 95% CI: 1.01-1.67, Pz = .041), respectively. For rs20541, the results suggested an association between rs20541 and COPD risk in Caucasians under the recessive model (OR = 2.79, 95% CI: 1.13-6.92, Pz = .026), whereas this SNP was not associated with COPD in Asians.This meta-analysis suggests that the T allele of rs1800925 is associated with the increased risk of COPD in both Asians and Caucasians, whereas rs20541 is associated with the risk of COPD in Caucasians but not in Asians.

Association between the TGF-β1 polymorphisms and chronic obstructive pulmonary disease: a meta-analysis

It has been hypothesized that polymorphisms in the transforming growth factor-β1 (TGF-β1) gene on chromosome 19 modify the risk for chronic obstructive pulmonary disease (COPD). However, results from previous studies are contradictory. We therefore conducted a meta-analysis of published case–control studies on the association between five common TGF-β1 polymorphisms (rs1982073, rs1800469, rs2241712, rs6957, and rs2241718) and COPD risk. Data sources were Pubmed, Scopus, ISI Web of Science, China National Knowledge Infrastructure (CNKI), and Wanfang databases. Twelve studies including 6749 participants were reviewed and analyzed. For the TGF-β1 polymorphism rs1982073, the results indicted that the C allele was associated with decreased risk of COPD in Caucasians (odds ratio (OR) =0.79, 95% confidence interval (CI): 0.64–0.99, P=0.038) but not in Asians (OR =0.95, 95% CI: 0.71–1.28, P=0.741). No associations with COPD were identified for other polymorphisms evaluated in the present study including rs1800469 (T allele compared with C allele, OR =0.89, 95% CI: 0.77–1.02, P=0.099), rs2241712 (A allele compared with G allele, OR =1.03, 95% CI: 0.89–1.20, P=0.666), rs6957 (A allele compared with G allele, OR =1.14, 95% CI: 0.95–1.36, P=0.160), and rs2241718 (C allele compared with T allele, OR =0.95, 95% CI: 0.79–1.14, P=0.571). In conclusion, this meta-analysis showed that the C allele of rs1982073 was protective against COPD in Caucasians but not in Asians, whereas there was no association of rs1800469, rs2241712, rs6957, and rs2241718 with COPD.

TNF-α -238, -308, -863 polymorphisms, and brucellosis infection

BACKGROUND

Brucella abortus is an intracellular bacterium that affects humans and domestic animals. Tumor necrosis factor-alpha (TNF-α) has been shown as a key player in the induction of cell-mediated resistance against Brucella infection. We aimed to evaluate the possible influence of the TNF-α promoter polymorphisms (-308 G/A, -238 G/A, and -863 C/A) on the susceptibility of human brucellosis.

METHODOLOGY

A total of 153 patients with active brucellosis and 128 healthy individuals were recruited. All subjects were genotyped for the polymorphisms in the TNF-α gene by Allele-Specific polymerase chain reaction analysis.

RESULTS

Our results showed that the TNF-α -308 GG genotype was significantly more frequently present in controls than in brucellosis patients (91% vs. 75%), thus was a protective factor against developing brucellosis (OR=0.313, p=0.001). In contrast, the -308 GA genotype (OR=3.026, p=0.002) and minor allele (A) (OR=3.058, p=0.001) as well as AAG haplotype (OR=4.014, p=0.001) conferred an increased risk of brucellosis. However, the -238 G/A and -863 C/A polymorphisms were not associated with the risk of brucellosis at both allelic and genotypic levels (p>0.05).

CONCLUSION

Our study revealed that the TNF-α -308 A allele or GA heterozygosity or AAG haplotype were associated with an increased risk of brucellosis in our population.

Novel aspects of pathogenesis and regeneration mechanisms in COPD

Chronic obstructive pulmonary disease (COPD), a major cause of death and morbidity worldwide, is characterized by expiratory airflow limitation that is not fully reversible, deregulated chronic inflammation, and emphysematous destruction of the lungs. Despite the fact that COPD is a steadily growing global healthcare problem, the conventional therapies remain palliative, and regenerative approaches for disease management are not available yet. We aim to provide an overview of key reviews, experimental, and clinical studies addressing lung emphysema development and repair mechanisms published in the past decade. Novel aspects discussed herein include integral revision of the literature focused on lung microflora changes in COPD, autoimmune component of the disease, and environmental risk factors other than cigarette smoke. The time span of studies on COPD, including emphysema, chronic bronchitis, and asthmatic bronchitis, covers almost 200 years, and several crucial mechanisms of COPD pathogenesis are described and studied. However, we still lack the holistic understanding of COPD development and the exact picture of the time-course and interplay of the events during stable, exacerbated, corticosteroid-treated COPD states, and transitions in-between. Several generally recognized mechanisms will be discussed shortly herein, ie, unregulated inflammation, proteolysis/antiproteolysis imbalance, and destroyed repair mechanisms, while novel topics such as deviated microbiota, air pollutants-related damage, and autoimmune process within the lung tissue will be discussed more extensively. Considerable influx of new data from the clinic, in vivo and in vitro studies stimulate to search for novel concise explanation and holistic understanding of COPD nowadays.

Association of tumor necrosis factor α -308G/A and interleukin-6 -174G/C gene polymorphism with pneumonia-induced sepsis

PURPOSE

Sepsis is a lethal outcome of the inflammation and coagulation process. Human interleukin (IL)-6 and tumor necrosis factor (TNF) α are well-known inflammation factors closely associated with sepsis. In the present study, we aim to investigate the association of promoter-region polymorphisms IL-6 (-174G/C) rs1800795 and TNF-α (-308G/A) rs1800629 with pneumonia-induced sepsis.

MATERIALS AND METHODS

A total of 277 Chinese patients with severe pneumonia-induced sepsis were recruited into this study. All study participants were admitted to the intensive care unit until discharge or death in the First Affiliated Hospital of Zhengzhou University from July 2010 to July 2014. The patients were classified as severely septic, septic shock, and mortality. Clinical data and demographic information were recorded. TaqMan genotyping was performed to detect single nucleotide polymorphism distribution.

RESULTS

The genotype results demonstrated that carriers of the TNF-α rs1800629 A allele had a 4.28-fold higher risk for septic shock (adjusted odds ratio [OR], 4.28; 95% confidence interval [CI], 2.24-8.18; P < .01) compared with severe sepsis, and carriers of the IL-6 rs1800795 C allele had a 2.42-fold higher risk for septic shock (OR, 2.42; 95% CI, 1.08-5.45; P < .01) compared with severe sepsis. No significant difference of SNP distribution was found between the survivors and the nonsurvivors. After the results were adjusted for age and the outcomes of blood cultures, a multivariate logistic regression analysis showed similar results. Individuals with the TNF-α 308 rs1800629 A allele (adjusted OR, 2.96; 95% CI, 1.30-7.87) or the IL-6 rs1800795 C allele (adjusted OR, 1.87; 95% CI, 1.03-3.61) had a higher prevalence of septic shock. However, these SNP distribution differences were not associated with mortality.

CONCLUSIONS

In intensive care unit patients, the TNF-α -308A allele and the IL-6 rs1800795 allele variants were susceptibility risk factors for septic shock induced by pneumonia.

Four SNPs in the CHRNA3/5 alpha-neuronal nicotinic acetylcholine receptor subunit locus are associated with COPD risk based on meta-analyses

Background

Several single nucleotide polymorphisms (SNPs) in an α-neuronal nicotinic acetylcholine receptor subunit (CHRNA3/5) were identified to be associated with chronic obstructive pulmonary disease (COPD) in a study based on a Norwegian population. However, results from subsequent studies have been controversial, particularly in studies recruiting Asians. In the present study, we conducted a comprehensive search and meta-analyses to identify susceptibility SNPs for COPD in the CHRNA3/5 locus.

Methods

A comprehensive literature search was conducted to find studies that have reported an association between SNPs in the CHRNA3/5 locus and COPD risk. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) for each SNP were calculated with the major allele or genotype as the reference group. The influence of individual studies on pooled measures was assessed, in addition to publication bias.

Results

A total of 12 articles with 14 eligible studies were included in this analysis. Association between 4 SNPs in the CHRNA3/5 locus and COPD was evaluated and included rs1051730, rs8034191, rs6495309, and rs16969968. Significant associations between the 4 SNPs and COPD were identified under allele (rs1051730: OR = 1.14, 95%CI = 1.10–1.18; rs8034191: OR = 1.29, 95%CI = 1.18–1.41; rs6495309: OR = 1.26, 95%CI = 1.09–1.45; rs16969968: OR = 1.27, 95%CI = 1.17–1.39) and genotype models. Subgroup analysis conducted for rs1051730 showed a significant association between this SNP and COPD risk in non-Asians (OR = 1.14, 95%CI = 1.10–1.18), but not Asians (OR = 1.23, 95%CI = 0.91–1.67). Rs1051730 and rs6495309 were also significantly associated with COPD after adjusting for multiple variables, including age and smoking status.

Conclusion

Our results indicate that 4 SNPs in the CHRNA3/5 locus are associated with COPD risk. Rs1051730 was particularly associated with COPD in non-Asians, but its role in Asians still needs to be verified. Additional studies will be necessary to assess the effect of rs6495309 on COPD. Although rs1051730 and rs6495309 were shown to be independent risk factors for COPD, validation studies should be performed.

Lack of association between the G+2044A polymorphism of interleukin-13 gene and chronic obstructive pulmonary disease: a meta-analysis

Numerous studies have investigated association of interleukin-13 (IL-13) G+2044A polymorphism with COPD susceptibility; however, the results were inconsistent and inconclusive. To evaluate the association between the IL-13 G+2044A polymorphism and susceptibility to COPD, a meta-analysis of published case-control studies was performed. Based on PubMed and Chinese database, this research selected studies that examined the association of the IL-13 G+2044A polymorphism with COPD. A genetic model-free approach was used to assess whether the combined data showed this association. Then a subgroup analysis was also performed, with stratifications for race, study design, and sample size. Six studies (total 1,213 COPD patients and 801 control subjects) for the IL-13 G+2044A polymorphism with COPD were included in the meta-analysis (G- vs A-allele: OR 1.12, 95 % CI 0.96-1.32, P = 0.15; genotypes GG+GA vs genotype AA: OR 0.99, 95 % CI 0.49-2.00, P = 0.98; genotype GG vs genotypes GA+AA: OR 1.18, 95 % CI 0.97-1.44, P = 0.09; genotype GA vs genotypes GG+AA: OR 0.85, 95 % CI 0.70-1.04, P = 0.11). This meta-analysis demonstrates that the IL-13 G+2044A polymorphism does not confer susceptibility to COPD. More detailed data about individual and environment, larger sample sizes with unbiased genotyping methods and matched controls in different populations are required.