Asthma susceptible genes in Chinese population: a meta-analysis

Overall and subgroup prevalence of self-reported asthma in US adults: a nationally representative cross-sectional study

BACKGROUND

The purpose of this study is to determine the variations in the prevalence of self-reported asthma among the adult population in the United States of America (USA), analyzing demographic characteristics, physical indicators, living habits, and sarcopenia.

METHODS

10,566 participants from the 2009 to 2018 National Health and Nutrition Examination Survey (NHANES) of the USA who were 20 years of age or older and not pregnant were included in the study.

RESULTS

The prevalence of patients with asthma varies by age, gender, and race. The weighted prevalence is 15.5%, estimated to represent 19.36 million people in the USA (95% CI, 14.5% to 16.6%). The prevalence of self-reported asthma decreases with age, with the highest prevalence among young adults aged 20-25 for both males and females. Females were also more susceptible to asthma compared to males. The increase in asthma prevalence attributed to smoking was most pronounced among African American and Caucasian participants (p < 0.05), while its effect on Mexican American and Asian participants was relatively minor. Notably, the prevalence of asthma was significantly higher in African American and Caucasian participants with sarcopenia compared to those without sarcopenia.

CONCLUSIONS

The prevalence of asthma is associated to varying degrees with factors such as age, gender, smoking, and the presence of sarcopenia. The elevated prevalence of asthma among young people and females warrants attention. Intensifying efforts toward smoking cessation and the scientific management of sarcopenia could be instrumental in reducing the incidence of asthma.

Trends in asthma among adults in the United States, National Health and Nutrition Examination Survey 2005 to 2018

BACKGROUND

Asthma is a common chronic disease in American adults. The prevalence of asthma has varied over time, but there are few studies on the long-term trend of asthma in American adults.

OBJECTIVE

To describe the prevalence and trend of asthma in American adults from 2005 to 2018 and analyze the risk factors for asthma.

METHODS

Data collection was performed from National Health and Nutrition Examination Survey 2005 to 2018. The unweighted number and weighted percentages of normal participants and patients with asthma and the trends of asthma were calculated. Weighted univariate logistic regression was used to analyze the risk factors for asthma.

RESULTS

A total of 39,601 adults were included in this study. From 2005 to 2018, the overall prevalence of asthma in American adults was 8.41%, whereas that in young, middle-aged, and elderly adults was 8.30%, 8.70%, and 7.92%, respectively. The estimated prevalence of asthma in the overall adults and young adults increased with time (P for trend = .03, difference = 0.023 and P for trend = .007, difference = 0.060, respectively), and the estimated prevalence of middle-aged and elderly adults remained stable with time (P for trend = .33, difference = 0.015 and P for trend = .80, difference = -0.024, respectively).

CONCLUSION

Asthma in American adults was on the rise. Female sex, non-Hispanic Blacks, individuals with low annual household income, active smokers, obese patients, patients with hypertension, patients with diabetes, and individuals with positive asthma family history were associated with a higher risk for developing asthma.

Association of +1923C > T, -1112C > T and +2044A > G Polymorphisms in IL-13 Gene with Susceptibility to Pediatric Asthma: A Systematic Review and Meta-Analysis

BackgroundPrevious studies have provided conflicting evidence implicating the IL-13 polymorphism and pediatric asthma. Thus, we performed a meta-analysis to combine and analyze the available studies to provide more accurate conclusions. Methods: A comprehensive retrieval in PubMed, EMBASE, Web of Science, and CNKI was performed up to February 05, 2020. Results: A total of 39 case-control studies including 15 studies with 4,968 cases and 7,091 controls were on +1923 C > T, ten studies with 3,175 cases and 2,983 controls on -1112 C > T, and 14 studies with 4,476 cases and 5,121 controls on +2044 A > G were selected. Pooled data showed that the IL-13 + 1923 C > T, -1112 C > T and +2044 A > G polymorphisms were significantly associated with risk of pediatric asthma. The IL-13 + 1923 C > T (Asians and Africans), -1112 C > T (Caucasians) and +2044 A > G (Asians) polymorphisms were more frequently associated in these ethnic groups. Conclusions: Our pooled data indicated that IL-13 + 1923 C > T, -1112 C > T and +2044 A > G polymorphisms were correlated with risk of pediatric asthma.

Angiotensin-converting enzyme insertion/deletion polymorphism and susceptibility to pediatric asthma: A meta-analysis

Objective:

The correlation of the angiotensin-converting enzyme (ACE) insertion/deletion (I/D) polymorphism with pediatric asthma risk was assessed in this meta-analysis.

Methods:

PubMed, Web of Science, Embase and CNKI databases were systematically searched for relevant literature, followed by application of odds ratios (OR) along with 95% confidence interval (CI) for determining the strength of relationship.

Results:

Seven articles with 802 cases and 632 controls fulfilled the inclusion criteria. As a result, the ACE I/D polymorphism was related to elevated pediatric asthma risk (D vs I: OR = 1.87, 95% CI = 1.59–2.20; dominant model: OR =1.53, 95% CI = 1.28–1.81; recessive model: OR =1.54, 95% CI = 1.28–1.85; DD vs II: OR =2.95, 95% CI = 2.19–3.98; DI vs II: OR = 0.96, 95% CI = 0.78–1.19). Subgroup analysis stratified by race revealed significant interrelation in Asians.

Conclusion:

This meta-analysis demonstrated that the ACE I/D polymorphism might be related to the risk of pediatric asthma.

Epistasis between phenylethanolamine N-methyltransferase and β2-adrenergic receptor influences extracellular epinephrine level and associates with the susceptibility to allergic asthma

BACKGROUND

Reduced extracellular epinephrine level often associates with asthma-related symptoms; however, the correlation between asthma and genetic variants in genes participating in the epinephrine signalling pathway remains unclear.

OBJECTIVE

To characterize the functions of single nucleotide polymorphisms (SNPs) in phenylethanolamine N-methyltransferase (PNMT) and β2-adrenergic receptor (ADRB2), and to study the effects, including both direct and epistatic, of these SNPs on serum epinephrine level and asthma susceptibility.

METHODS

Single nucleotide polymorphisms functions were characterized through in vitro luciferase assay. ADRB2 gene expression level in peripheral blood mononuclear cell (PBMC) was measured by transcriptome sequencing and expression microarray on two separate Asian cohorts (NUS-UTAR, n = 278 and NUS-TA, n = 58). Serum epinephrine level was assessed on a Singapore Chinese cohort (NUS-SH, n = 314) with 155 asthmatic and 159 non-asthmatic subjects. A separate Singapore Chinese cohort (NUS-G, n = 3009) was genotyped to show disease association (direct and epistatic effect) of functional SNPs in PNMT and ADRB2.

RESULTS

Reduced serum epinephrine level was associated with increased asthma risk in Singapore Chinese. The minor allele of rs876493 was shown to increase PNMT promoter activity and reduce asthma risk. Multiple SNPs in ADRB2 forms a haplotype that was associated with the differential promoter activity of this gene. In this haplotype, rs11168070 was associated directly with ADRB2 expression in PBMCs. Both minor alleles from rs876493 and rs11168070 contribute synergistically to reduce asthma risk and increase serum epinephrine level.

CONCLUSION AND CLINICAL RELEVANCE

Epistatic interaction between genetic variants from PNMT (rs876493) and ADRB2 (rs11168070) is associated with serum epinephrine level and the susceptibility of asthma. Our findings improved the current understanding of the genetic basis of this disease, while genotypic states of these SNPs may serve as potential biomarkers to predict susceptibility to the disease.

Association of β2-adrenergic receptor gene polymorphisms (rs1042713, rs1042714, rs1042711) with asthma risk: a systematic review and updated meta-analysis

Background

The published data on the association between β2-adrenergic receptor gene polymorphisms and asthma susceptibility are inconclusive. To derive a more precise estimation of this association, a meta-analysis was performed.

Methods

A literature search was conducted in PubMed, Web of Science, EMBASE, Wanfang, and the China National Knowledge Infrastructure (CNKI) databases to identify eligible studies. The pooled odds ratios (ORs) with corresponding 95% confidence intervals (CIs) were used to calculate the strength of the association. A sensitivity analysis was performed to evaluate the influence of individual studies on the overall effect estimates, and funnel plots and Egger’s tests were used for indications of publication bias.

Results

Seventy three studies with three single nucleotide polymorphisms (SNP) (rs1042713, c.G46A, p.Gly16Arg; rs1042714, c.G79C, p.Gln27Glu; rs1042711, c.T-47C, p.Cys19Arg) were finally identified. For the rs1042713 polymorphism, no significant association with asthma risk was found in the overall population. However, a significant protective association was found in the Indian population in the dominant model comparison (OR = 0.72, 95% CI = 0.59–0.87, I² = 25%, studies = 5, cases = 1190, controls = 1241). A significant risk association was found in the Arab population in the dominant model comparison (OR = 1.75, 95% CI = 1.14–2.70, I² = 0%, studies = 2, cases = 307, controls = 361) and the homozygote model comparison (OR = 1.88, 95% CI = 1.17–3.02, I² = 0%, studies = 2, cases = 307, controls = 361), and in the Hispanic-Latino population in the dominant model comparison (OR = 1.68, 95% CI = 1.10–2.55, I² = 77%, studies = 5, cases = 1026, controls = 1412). For the rs1042714 polymorphism, we found a significant association in the recessive model comparison (OR = 0.83, 95% CI = 0.70–0.98, I² = 44%, studies = 52, cases = 8242, controls = 16,832), the homozygote genotype comparison (OR = 0.84, 95% CI = 0.72–0.98, I² = 25%, studies = 52, cases = 8242, controls = 16,832) and the allelic genetic model (OR = 0.91, 95% CI = 0.83–0.99, I² = 59%, studies = 52, cases = 8242, controls = 16,832) in the overall population. When stratified by age, a significant association was also found in children in the recessive model comparison (OR = 0.59, 95% CI = 0.39–0.88, I² = 58%, studies = 18, cases = 2498, controls = 2510) and the homozygote genotype comparison (OR = 0.63, 95% CI = 0.43–0.92, I² = 46%, studies = 18, cases = 2498, controls = 2510), but not in adult. For the rs1042711 polymorphism, no significant associations were found in the any genetic model.

Conclusion

The meta-analysis suggests that the ADRB2 rs1042714 polymorphism has a protective association with asthma in the overall population and the pediatric subgroup.

Association of FcεRIβ polymorphisms with risk of asthma and allergic rhinitis: evidence based on 29 case-control studies

Purpose: Accumulating evidence has shown that allergic diseases are caused by a complex interaction of genetic and environmental factors, some single nucleotide polymorphisms (SNPs) existing in high-affinity IgE receptor β chain (FcεRIβ) are potential risk factors for allergic diseases. However, the results have been inconsistent and inconclusive due to the limited statistical power in individual study. Thus, we conducted a meta-analysis to systematically evaluate the association between FcεRIβ SNPs and allergic diseases risk.

Methods: Eligible studies were collected from PubMed, Embase, Web of Science, Chinese National Knowledge Infrastructure, and WanFang databases. Pooled odd ratios (ORs) and corresponding 95% confidence intervals (95% CIs) were calculated to assess the strength of the relationships between five polymorphisms (E237G, -109 C/T, RsaI_in2, RsaI_ex7, and I181L) and the risk of allergic diseases by using five genetic models. In addition, the stability of our analysis was evaluated by publication bias, sensitivity, and heterogeneity analysis.

Results: Overall, a total of 29 case–control studies were included in this meta-analysis. We found that E237G (B vs. A: OR = 1.28, 95% CI = 1.06–1.53, P<0.001, I² = 63.1%) and -109 C/T (BB vs. AA + AB: OR = 1.58, 95%CI = 1.26–1.98, P<0.001, I² = 66.4%) were risk factors for allergic diseases.

Conclusion: Our meta-analysis suggests that polymorphisms in FcεRIβ may be associated with the development of allergic diseases.

Association Between TGF-β1 Polymorphisms and Asthma Susceptibility Among the Chinese: A Meta-Analysis

OBJECTIVE

Asthma is the most common chronic pulmonary disease in China and is characterized by airway inflammation and episodic airflow obstruction. The aim of this meta-analysis was to evaluate the relation of two transforming growth factor-β1 (TGF-β1) polymorphisms with asthma risk in Chinese population.

METHODS

PubMed, Springer, EMBASE, MEDLINE, CNKI (China National Knowledge Infrastructure), and Wanfang databases were used to search and retrieve relevant eligible case-control studies published through December 2017. The odds ratios (OR) and 95% confidence intervals (CI) were used to evaluate the effect.

RESULTS

A total of 2040 asthma patients and 1952 controls from 12 studies were analyzed. Two polymorphic sites of TGF-β1 gene were identified: -509C/T and +869T/C. We found that the -509C/T polymorphism was associated with increased asthma risk under the heterozygous model (CT vs. CC: OR = 1.40, 95% CI = 1.03-1.90, p = 0.03) and the dominant model (TT+CT vs. CC: OR = 1.41, 95% CI = 1.05-1.90, p = 0.02). Subgroup analyses by age suggested that -509C/T variant was associated with childhood asthma. Analysis of disease severity indicated that this variant was associated with both mild-to-moderate asthma and severe asthma. However, the +869T/C polymorphism was not associated with asthma susceptibility in subgroup analysis by age or disease severity.

CONCLUSIONS

This study demonstrated that the -509C/T polymorphism of the TGF-β1 gene might be a risk factor for asthma in the Chinese population, especially in Chinese children. Further large-scale case-control studies are still required.

AGTR2 absence or antagonism prevents cystic fibrosis pulmonary manifestations

BACKGROUND

Pulmonary disease remains the primary cause of morbidity and mortality for individuals with cystic fibrosis (CF). Variants at a locus on the X-chromosome containing the type 2 angiotensin II receptor gene (AGTR2) were identified by a large GWAS as significantly associating with lung function in CF patients. We hypothesized that manipulating the angiotensin-signaling pathway may yield clinical benefit in CF.

METHODS

Genetic subset analysis was conducted on a local CF cohort to extend the GWAS findings. Next, we evaluated pulmonary function in CF mice with a deleted AGTR2 gene, and in those who were given subcutaneous injections of PD123,319, a selective AGTR2 antagonist for 12 weeks beginning at weaning.

RESULTS

The genetic subset analysis replicated the initial GWAS identified association, and confirmed the association of this locus with additional lung function parameters. Studies in genetically modified mice established that absence of the AGTR2 gene normalized pulmonary function indices in two independent CF mouse models. Further, we determined that pharmacologic antagonism of AGTR2 improved overall pulmonary function in CF mice to near wild-type levels.

CONCLUSIONS

These results identify that reduced AGTR2 signaling is beneficial to CF lung function, and suggest the potential of manipulating the angiotensin-signaling pathway for treatment and/or prevention of CF pulmonary disease. Importantly, the beneficial effects were not CF gene mutation dependent, and were able to be reproduced with pharmacologic antagonism. As there are clinically approved drugs available to target the renin-angiotensin signaling system, these findings may be quickly translated to human clinical trials.

Arterial aging mediates the effect of TNF-α and ACE polymorphisms on mental health in elderly individuals: insights from IKARIA study

BACKGROUND

Aging is characterized by an insidious decline in cognitive function. Several genetic and lifestyle factors have been implicated in the increased risk or early onset of dementia.

AIM

We sought to assess the role of tumor necrosis factor (TNF) and angiotensin-converting enzyme (ACE) polymorphisms on the development of impaired mental health in respect to indices of arterial aging in nonagenarian individuals.

DESIGN

178 consecutive subjects above 75 years that permanently inhabit in the island of IKARIA, Greece were recruited.

METHODS

Aortic distensibility (AoD) was calculated and genetic evaluation was performed on the ACE Insertion/Deletion gene polymorphism (intron 16) and the G/A transition (position -308) of the TNF gene. Cognitive function was evaluated using the Mini-mental State Examination (MMSE).

RESULTS

The DD genotype for ACE was independently associated ( b  = -0.44, P = 0.007) with AD while AoD remained an independent determinant of mental status (OR = 1.82, P = 0.036). Interestingly though, when a combined genetic index (GI) was calculated for both genes (ACE and TNF), subjects being double homozygous (DD for ACE and GG for TNF) for these loci presented significantly decreased MMSE (adjusted OR = 0.259, P = 0.033). This GI independently associated with AD (beta coefficient = -0.785, P = 0.002). When AoD was included, GI lost its predictive role (OR = 0.784, P = 0.783) towards MMSE. AoD has marginal indirect mediating effect in the association of the GI with MMSE ( P = 0.07).

CONCLUSION

Vascular aging may modulates the genetic substrate of elderly subjects on the risk for developing dementia.

T1 polymorphism in a disintegrin and metalloproteinase 33 (ADAM33) gene may contribute to the risk of childhood asthma in Asians

OBJECTIVE

Polymorphisms in ADAM33 gene have been implicated in susceptibility to the risk of childhood asthma. However, the results remain controversial. We performed meta-analyses to clarify the relationship between them.

METHODS

Relevant articles were searched in PubMed, Embase, Wanfang, and China National Knowledge Infrastructure. The Odds ratio (OR) with 95% confidence interval (CI) was used to assess the strength of the associations.

RESULTS

Fourteen studies with five ADAM33 polymorphisms (F + 1, T1, T2, S2, and V4) were identified, involving 2687 cases and 2996 controls. ADAM33 F + 1, T2, and T1 polymorphisms showed significant associations with asthma risks in the overall and Caucasian children, Asian children, and Caucasian and Chinese children, respectively; however, these significant results were unstable in sensitivity analysis. T1 revealed significant and stable associations with asthma risks among Asian children in the dominant (OR = 2.00, 95% CI = 1.40-2.87, P = 0.0002) and codominant (OR = 3.06, 95% CI = 1.71-5.50, P = 0.0002) models; in cumulative meta-analyses, these significant results were robust. Concerning S2 or V4 polymorphism, no significant associations were observed.

CONCLUSION

These findings demonstrate that ADAM33 T1 polymorphism might be a potential susceptible predictor of asthma for Asian children. Further functional studies between this polymorphism and asthma risks are warranted.

Association between IL-13 +1923C/T polymorphism and asthma risk: a meta-analysis based on 26 case-control studies

Asthma is a serious and hereditary respiratory disorder affecting all age groups. Interleukin-13 (IL-13) is a central regulator of allergic inflammation. The purpose of the present study was to estimate the relationship between IL-13 +1923C/T polymorphism and asthma susceptibility. Relevant case-control studies published between January 2000 and July 2016 were searched in the online databases. Review Manage (RevMan) 5.3 was used to conduct the statistical analysis. The pooled odds ratio (OR) with its 95% confidence interval (CI) was employed to calculate the strength of association. A total of 26 articles were retrieved, including 17642 asthma patients and 42402 controls. Overall, our results found that IL-13 +1923C/T polymorphism was significantly associated with increased risk of asthma under each genetic model (P<0.00001). Subgroup analysis by ethnicity showed that alleles and genotypes of this variant correlated with asthma among Asians and Caucasians, but only TT genotype under the homozygote model in Africans. When stratified by age group, this variant highly correlated with asthma in children and moderately in adults. Furthermore, the TT, CT and CC genotypes in asthma group were all significantly associated with increased IgE levels in sera of asthma patients when compared with controls. Our results suggested that IL-13 +1923C/T polymorphism contributed to the development of asthma. Further case-control studies with more ethnicities are still needed.

ADRB2 polymorphisms in allergic asthma in Han Chinese children

BACKGROUND

Single-nucleotide polymorphisms (SNPs) in the human β2 adrenergic receptor (ADRB2) gene have been linked to pathogenesis of and treatment responses in asthma. In China, where asthma is common, little information exists regarding ADRB2 variants and their effects on asthma. The current study sought to investigate the relationship between variations in ADRB2 and childhood asthma.

METHODS

Blood samples were collected from 298 pediatric asthma cases treated in our hospital from July 2013 to September 2014; 304 samples were collected from healthy children for a control group. Six loci (at base positions -47, 79, -2387, 46, 523, and 491) of ADRB2 were genotyped using the TaqMan probe assay; SHEsis was used to determine haplotypes. Allele frequencies and genotype distributions were compared between groups using chi square and t tests.

RESULTS

No significant differences in genotype or allele frequencies were found between the groups for the polymorphic loci -2387 bp (T>C), 46 bp (G>A), and 523 bp (C>A) (p > 0.05). However, genotype frequencies for the ADRB2 SNPs at -47 bp (C>T) and 79 bp (G>C) differed significantly between asthma and control groups (p < 0.05). Further, linkage disequilibrium was found between these 2 SNPs (D' = 0.990, r(2) = 0.962), as well as between SNPs at 46 and 523 bp (D' = 0.985, r(2) = 0.607). Finally, of the 4 haplotypes analyzed in these samples (haplotypes III, IV, IX, and XI), the frequency of haplotype III was significantly lower in the asthma group than the control group (p < 0.05; odds ratio [OR] = 0.72; 95% confidence interval [CI], 0.48 to 0.97).

CONCLUSION

Variations of ADRB2 at base positions -47 (C>T) and 79 (G>C), as well as haplotype III, may contribute to susceptibility to childhood asthma.

Bed-sharing and related factors in early adolescents

OBJECTIVE

To investigate the prevalence of bed-sharing and examine correlates of bed-sharing habits in early adolescents.

METHODS

Participants were 1452 early adolescents from 10 primary schools in Shanghai, China. Children's health status and past history, family environment and parents' attitude towards bed-sharing, and children's sleep arrangements were surveyed. Sleep was assessed by the Children's Sleep Habit Questionnaire. Tanner stage was determined by the endocrinologist.

RESULTS

The median of age was 10.83 years (range: 9.42-12.92; 95% confidence interval [CI]: 10.79-10.83) and boys accounted for 51.17%. The prevalence of bed-sharing was 16.8%. Positive parental attitude toward bed-sharing (OR: 9.87; 95% CI: 6.57-14.83), asthma (OR: 2.15; 95% CI: 1.16-3.98), smaller residential space (OR: 1.90; 95% CI: 1.17-3.09), extended family (OR: 1.59; 95% CI: 1.16-2.18), and being physically less mature (OR: 2.39; 95% CI: 1.16-4.91) increased the likelihood of bed-sharing. Bed-sharers were more likely to have bedtime resistance (OR: 12.20; 95% CI: 8.59-17.33), sleep anxiety (OR: 3.76; 95% CI: 2.74-5.15), and poor sleep quality (OR: 3.21; 95% CI: 2.28-4.81) compared to non-bed-sharers. Furthermore, bed-sharing was associated with daytime sleepiness (OR: 1.53; 95% CI: 1.10-2.13) but not with sleep duration.

CONCLUSIONS

Bed-sharing is highly prevalent among Chinese early adolescents and is significantly related to sleep quality. Parental positive attitude toward bed-sharing was the most determining factor.

The regulated upon activation normal T-cell expressed and secreted (RANTES) -28C/G and -403G/A polymorphisms and asthma risk: a meta-analysis

BACKGROUND AND OBJECTIVES

Genetic studies have revealed that the regulated upon activation normal T-cell expressed and secreted (RANTES) -28C/G and -403G/A polymorphisms are associated with asthma risk, but contradictory findings have also been reported. Therefore, we undertook a meta-analysis on this topic.

METHODS

The PubMed, Web of Science, China National Knowledge Infrastructure (CNKI), and Wanfang databases were used to identify relevant studies published in the medical literature from 1990 to March 26, 2014. Nine studies (containing 2,103 cases and 2,876 controls) investigated the -28C/G polymorphism, and 11 studies (including 2,015 cases and 1,909 controls) assessed the -403G/A polymorphism.

RESULTS

The pooled results demonstrated that the -28C/G polymorphism was not associated with asthma risk in the overall populations (Caucasians, Asians, and a mixed population). However, in subgroup analysis according to age, the -28G allele was associated with an increased risk of asthma in children (odds ratio [OR] 1.27, 95 % confidence interval [CI] 1.03-1.57, P value for heterogeneity [P het] = 0.163, P value for the overall effect [P z] = 0.028). When we further stratified the studies performed in children on the basis of ethnicity, we found that the -28G allele was associated with an increased risk of asthma in Asian children (OR 1.28, 95 % CI 1.02-1.62, P het = 0.127, P z = 0.035), but not in Caucasian children (OR 1.20, 95 % CI 0.68-2.12, P het = 0.137, P z = 0.530). In subgroup analysis by asthma phenotype, no association between either atopic or non-atopic asthma and the -28C/G polymorphism was identified. For the -403G/A polymorphism, meta-analysis showed no association with asthma risk in the overall populations (Caucasians, Asians, and black people). In subgroup analyses by age, ethnicity, and asthma phenotype, we still did not find any association between the -403G/A polymorphism and asthma.

CONCLUSION

Current findings suggest an association between the -28G allele and asthma risk in Asian children but not in Caucasian children.

Higher TGF-β with lower CD124 and TSLP, but no difference in PAR-2 expression in bronchial biopsy of bronchial asthma patients in comparison with COPD patients

Chronic obstructive pulmonary disease (COPD) and bronchial asthma (BA) are 2 severe respiratory disorders with different predominated immunopathologies. There are several "novel molecules" from different families that are proposed as part of the etiopathogenesis of COPD and BA. Proteinase-activated receptor 2 (PAR-2), thymic stromal lymphoprotein (TSLP), interleukin-4 and its receptor (CD124), Yin-Yang 1 (YY1), and transforming growth factor beta (TGF-β) have been previously shown to be involved in the pathophysiology of both these diseases. We investigated PAR-2, TSLP, CD124 (interleukin-4R), TGF-β, and YY1 immunohistochemical expression in endobronchial and transbronchial biopsies from 22 BA patients and 20 COPD patients. Immunostaining for the above-mentioned antigens was quantified using a modified semiquantitative scoring system and statistically evaluated. The values of TGF-β in the epithelial cells (P=0.0007) and TGF-β in the submucosa (P=0.0075) were higher in the BA samples, whereas values of CD124 (P=0.0015) and TSLP (P=0.0106) were higher in the COPD samples. No statistically significant differences between the groups were recorded for PAR-2 and YY1. Airway inflammatory reaction diversity in BA and COPD seems to be disease specific; however, there are also shared mechanisms involved in the pathophysiology of both diseases.

Asthma Phenotypes in Japanese Adults - Their Associations with the CCL5 ADRB2 Genotypes

BACKGROUND

Cluster analyses were previously performed to identify asthma phenotypes underlying asthma syndrome. Although a large number of patients with asthma develop the disease later in life, these previous cluster analyses focused mainly patients with younger-onset asthma.

METHODS

Cluster analysis examined the existence of distinct phenotypes of late-onset asthma in Japanese patients with adult asthma. We then associated genotypes at the CCL5, TSLP, IL4, and ADRB2 genes with the clusters of asthma identified.

RESULTS

Using the 8 variables of age, sex, age at onset of the disease, smoking status, total serum IgE, %FEV1, FEV1/FVC, and specific IgE responsiveness to common inhaled allergens, two-step cluster analysis of 880 Japanese adult asthma patients identified 6 phenotypes: cluster A (n = 155): older age at onset, no airflow obstruction; cluster B (n = 170): childhood onset, normal-to-mild airflow obstruction; cluster C (n = 119): childhood onset, the longest disease duration, and moderate-to-severe airflow obstruction; cluster D (n = 108): older age at onset, severe airflow obstruction; cluster E (n = 130): middle-age at onset, no airflow obstruction; and cluster F (n = 198): older age at onset, mild-to-moderate airflow obstruction. The CCL5-28C>G genotype was significantly associated with clusters A, B and D (OR 1.65, p = 0.0021; 1.67, 0.018; and 1.74, 0.011, respectively). The ADRB2 Arg16Gly genotype was also associated with clusters B and D (OR 0.47, p = 0.0004; and 0.63, 0.034, respectively).

CONCLUSIONS

The current cluster analysis identified meaningful adult asthma phenotypes linked to the functional CCL5 and ADRB2 genotypes. Genetic and phenotypic data have the potential to elucidate the pheno- typic heterogeneity and pathophysiology of asthma.

A systematic appraisal of field synopses in genetic epidemiology: a HuGE review

Evidence from genetic association studies is accumulating rapidly. Field synopses have recently arisen as an unbiased way of systematically synthesizing this evidence. We performed a systematic review and appraisal of published field synopses in genetic epidemiology and assessed their main findings and methodological characteristics. We identified 61 eligible field synopses, published between January 1, 2007, and October 31, 2013, on 52 outcomes reporting 734 significant associations at the P < 0.05 level. The median odds ratio for these associations was 1.25 (interquartile range, 1.15-1.43). Egger's test was the most common method (n = 30 synopses) of assessing publication bias. Only 12 synopses (20%) used the Venice criteria to evaluate the epidemiologic credibility of their findings (n = 449 variants). Eleven synopses (18%) were accompanied by an online database that has been regularly updated. These synopses received more citations (P = 0.01) and needed a larger research team (P = 0.02) than synopses without an online database. Overall, field synopses are becoming a valuable tool for the identification of common genetic variants, especially when researchers follow relevant methodological guidelines. Our work provides a summary of the current status of the field synopses published to date and may help interested readers efficiently identify the online resources containing the relevant genetic evidence.

Association between polymorphisms and haplotypes of the beta-2 adrenergic receptor gene and asthma in a Chinese Han population

Conflicting data have been reported on the association of variants of the beta-2 adrenergic receptor (ADRB2) gene with asthma etiology. To provide a scientific basis for the prevention and treatment of asthma, the relationship between single nucleotide polymorphisms and haplotypes of ADRB2 and asthma was examined in a Chinese Han population. Six loci (base positions -2387, -47, 46, 79, 491, and 523) of ADRB2 were examined in a group of individuals with asthma (n = 429) and a control group of individuals who do not have the disease (n = 483). Polymorphisms at the -47 locus [odds ratio (OR) = 0.789, 95% confidence interval (CI): 0.398~0.961, P < 0.05) and the 79 locus (OR = 0.788, 95% CI: 0.394~0.948, P < 0.05) and haplotype III (CCGGC; OR = 0.705, 95% CI: 0.412~0.973, P < 0.05) were correlated with asthma susceptibility and may affect the incidence of asthma in a Chinese Han population by conferring a protective effect. By examining several polymorphisms and haplotypes, this study yields a more comprehensive examination of the role of the ADRB2 gene in the pathogenesis of asthma.

Association of ADAM33 gene polymorphisms with allergic asthma

OBJECTIVES

Asthma results from the interaction between genetic and environmental factors. ADAM33 gene on chromosome 20p13 is associated with asthma and airway hyperresponsiveness.

MATERIALS AND METHODS

This is a case-control study, where four SNPs S1 (rs3918396), T1 (rs2280091), T2 (rs2280090), V4 (rs2787094) of ADAM33 gene have been assessed in patients with allergic asthma and normal controls (95 patients and 86 normal). Blood samples of these participants have been genotyped by PCR and the RFLP method.

RESULTS

There was no association between asthmatic patients and polymorphisms of alleles, genotypes and haplotypes of the ADAM33 gene. When categorizing the asthmatic patients in severe, moderate and mild groups, associations in the subcategories of asthmatic patients were found. There were associations between polymorphisms of C allele of T1 SNP with severe asthmatic patients and G allele of V4 SNP with moderate asthmatics respectively (P=0.006, P=0.01). There was a significant association between sensitivity to mite and polymorphism of C allele of T1 SNP (P=0.02). Besides, there was a significant association between sensitivity to weeds and genotype GG of V4 SNP (P=0.05).

CONCLUSION

Polymorphisms of ADAM33 gene might be associated with severe asthma and sensitivity to aeroallergens in northeast of Iran, but further studies are needed to determine the polymorphisms in this area and other regions of our country.

Association between RANTES gene polymorphisms and asthma: a meta-analysis

BACKGROUND

A few recent studies have suggested that regulated on activation, normal T cell expressed and secreted (RANTES) polymorphisms (-403 G/A, -28C/G) are associated with asthma. However, there still existed studies which did not confirm these correlations.

OBJECTIVE

The objective of this study was to evaluate the relationship of RANTES and asthma using a meta-analysis.

METHODS

Pubmed, Embase, and Cochrane library databases were systemically searched. Data were extracted by two independent reviewers and pooled odds ratio (OR) with 95% confidence interval (CI) were calculated.

RESULTS

Eighteen studies were enrolled, including a total of 2558 cases and 2630 controls of -403 G/A, as well as 3311 cases and 4031 controls of -28C/G in this meta-analysis. The overall ORs and 95% CIs of -403 G/A were 1.19, 1.06-1.33 (P<0.001) and 1.25, 1.03-1.51 (P = 0.933) in dominant and recessive models, respectively. The overall ORs and 95% CIs of -28G were 1.23, 1.09-1.39 (P = 0.221) and 1.76, 1.32-2.34 (P = 0.356) in dominant and recessive models, respectively. No publication bias among studies was showed.

CONCLUSIONS

This meta-analysis showed that RANTES -403 G/A polymorphism was a risk factor for asthma, while -28C/G polymorphism were not associated with asthma.

Association of interleukin-13 SNP rs20541 (Arg>Gln) to allergic rhinitis in an Asian population of ethnic Chinese in Singapore

In this study, we report our findings as we evaluated the association of IL-13 SNP rs20541 to AR as reported in the meta-analysis (Ying, X-J et al., April, Gene 2013) in an Asian population of 1322 ethnic Chinese recruited in Singapore well defined and characterized for allergic rhinitis. The SNP was significantly associated with AR at an odds ratio of 1.57 for the homozygous genotype comparisons indicating a strong risk for AR. This highlights the importance of this mutation in Asian populations for risk towards allergic phenotypes and also warrants further functional work to characterize the mechanism behind this genetic predisposition.

A disintegrin and metalloprotease 33 (ADAM33) gene polymorphisms and the risk of asthma: a meta-analysis

Polymorphisms in the ADAM33 gene have been associated with asthma, but the data are controversial. Therefore, we reviewed the related studies and quantitatively summarized the associations between ADAM33 polymorphisms and asthma risk using meta-analysis. A dominant model (AA+Aa vs. aa), recessive model (AA vs. Aa+aa), additive model (AA vs. aa) and allelic model (A vs. a) were used to estimate the association between ADAM33 polymorphism and asthma risk. A total of 29 case-control studies referring to 14 SNPs were identified: rs2280091(T1), rs2787094(V4), rs528557(S2), rs2280090(T2), rs511898(F+1), rs44707(ST+4), rs3918396(S1), rs543749(V-1), rs574174(ST+7), rs597980(ST+5), rs2853209(S+1), rs2280089(T+1), rs612709(Q-1), and rs3746631(V5). The results indicated that S1, V-1, V5, S+1, S2, ST+4, ST+7, ST+5, and Q-1 were not associated with asthma. Significant associations were found with the T1, V4, F+1 and T+1 polymorphisms in the overall population. In the subgroup analysis by ethnicity, a positive result was only found for the T1, V4, F+1 and T2 polymorphisms in Asia but not in Europe or Latin America. This meta-analysis provides evidence that the T1, V4, F+1, T2, and T+1 polymorphisms in the ADAM33 gene are risk factors for asthma, especially in the Asian population.

Regulation of a disintegrin and metalloprotease-33 expression by transforming growth factor-β

The asthma susceptibility gene, a disintegrin and metalloprotease-33 (ADAM33), is selectively expressed in mesenchymal cells, and the activity of soluble ADAM33 has been linked to angiogenesis and airway remodeling. Transforming growth factor (TGF)-β is a profibrogenic growth factor, the expression of which is increased in asthma, and recent studies show that it enhances shedding of soluble ADAM33. In this study, we hypothesized that TGF-β also affects ADAM33 expression in bronchial fibroblasts in asthma. Primary fibroblasts were grown from bronchial biopsies from donors with and those without asthma, and treated with TGF-β(2) to induce myofibroblast differentiation. ADAM33 expression was assessed using quantitative RT-PCR and Western blotting. To examine the mechanisms whereby TGF-β(2) affected ADAM33 expression, quantitative methylation-sensitive PCR, chromatin immunoprecipitation, and nuclear accessibility assays were conducted on the ADAM33 promoter. We found that TGF-β(2) caused a time- and concentration-dependent reduction in ADAM33 mRNA expression in normal and asthmatic fibroblasts, affecting levels of splice variants similarly. TGF-β(2) also induced ADAM33 protein turnover and appearance of a cell-associated C-terminal fragment. TGF-β(2) down-regulated ADAM33 mRNA expression by causing chromatin condensation around the ADAM33 promoter with deacetylation of histone H3, demethylation of H3 on lysine-4, and hypermethylation of H3 on lysine-9. However, the methylation status of the ADAM33 promoter did not change. Together, these data suggest that TGF-β(2) suppresses expression of ADAM33 mRNA in normal or asthmatic fibroblasts. This occurs by altering chromatin structure, rather than by gene silencing through DNA methylation as in epithelial cells. This may provide a mechanism for fine regulation of levels of ADAM33 expression in fibroblasts, and may self-limit TGF-β(2)-induced ectodomain shedding of ADAM33.

The -159C/T polymorphism in the CD14 gene and the risk of asthma: a meta-analysis

The -159C/T polymorphism in the CD14 gene has been implicated in susceptibility to asthma, but a large number of studies have reported inconclusive results. The aim of this study is to investigate the association between the -159C/T polymorphism in the CD14 gene and the risk of asthma by meta-analysis. We searched Pubmed, Embase, CNKI database, Wanfang database, Weipu database, and Chinese Biomedical database, covering all publications (last search been performed on April 20, 2010). Statistical analysis was performed by using the softwares Revman 4.2 and STATA 10.0. A total of 17 case-control studies in 17 articles (4,246 cases and 3,631 controls) were included in this meta-analysis. There was no association between this polymorphism and asthma risk in combined analyses (odds ratio (OR) = 0.86 and 95% confidence interval (95% CI) = 0.72-1.02, P = 0.09 for TC + TT vs. CC). In the subgroup analysis by age, ethnicity, and atopic status, no significant associations of asthma risks were obtained from age groups, ethnic groups, and atopic groups for TC + TT vs. CC comparison. For atopic population, significant decreased atopic asthma risks were found among Asian population (OR = 0.69, 95% CI 0.52-0.92, P = 0.01) and children population (OR = 0.69, 95% CI 0.54-0.89, P = 0.0004) for TC + TT vs. CC comparison. This meta-analysis suggests that CD14 is a candidate gene for atopic asthma susceptibility. The -159C/T polymorphism may be a protective factor for atopic asthma in Asian and children. More studies are needed to validate these associations.