Micro-RNAs: Crossroads between the Exposure to Environmental Particulate Pollution and the Obstructive Pulmonary Disease

Environmental pollution has reached a global echo and represents a serious problem for human health. Air pollution encompasses a set of hazardous substances, such as particulate matter and heavy metals (e.g., cadmium, lead, and arsenic), and has a strong impact on the environment by affecting groundwater, soil, and air. An adaptive response to environmental cues is essential for human survival, which is associated with the induction of adaptive phenotypes. The epigenetic mechanisms regulating the expression patterns of several genes are promising candidates to provide mechanistic and prognostic insights into this. Micro-RNAs (miRNAs) fulfil these features given their ability to respond to environmental factors and their critical role in determining phenotypes. These molecules are present in extracellular fluids, and their expression patterns are organ-, tissue-, or cell-specific. Moreover, the experimental settings for their quantitative and qualitative analysis are robust, standardized, and inexpensive. In this review, we provide an update on the role of miRNAs as suitable tools for understanding the mechanisms behind the physiopathological response to toxicants and the prognostic value of their expression pattern associable with specific exposures. We look at the mechanistic evidence associable to the role of miRNAs in the processes leading to environmental-induced pulmonary disease (i.e., chronic obstructive pulmonary disease).

Club Cell Secretory Protein Deficiency Leads to Altered Lung Function

RATIONALE

CC16 (club cell secretory protein-16), a member of the secretoglobin family, is one of the most abundant proteins in normal airway secretions and has been described as a serum biomarker for obstructive lung diseases.

OBJECTIVES

To determine whether low CC16 is a marker for airway pathology or is implicated in the pathophysiology of progressive airway damage in these conditions.

METHODS

Using human data from the birth cohort of the Tucson Children's Respiratory Study, we examined the relation of circulating CC16 levels with pulmonary function and responses to bronchial methacholine challenge from childhood up to age 32 years. In wild-type and CC16-/- mice, we set out to comprehensively examine pulmonary physiology, inflammation, and remodeling in the naive airway.

MEASUREMENTS AND MAIN RESULTS

We observed that Tucson Children's Respiratory Study participants in the lowest tertile of serum CC16 had significant deficits in their lung function and enhanced airway hyperresponsiveness to methacholine challenge from 11 years throughout young adult life. Similarly, CC16-/- mice had significant deficits in lung function and enhanced airway hyperresponsiveness to methacholine as compared with wild-type mice, which were independent of inflammation and mucin production. As compared with wild-type mice, CC16-/- mice had significantly elevated gene expression of procollagen type I, procollagen type III, and α-smooth muscle actin, areas of pronounced collagen deposition and significantly enhanced smooth muscle thickness.

CONCLUSIONS

Our findings support clinical observations by providing evidence that lack of CC16 in the lung results in dramatically altered pulmonary function and structural alterations consistent with enhanced remodeling.

Understanding alpha-1 antitrypsin deficiency: A review with an allergist's outlook

Alpha-1 antitrypsin (AAT) is the prototypical protease inhibitor from the serine protease inhibitor (serpin) superfamily that protects lung tissue from proteolytic damage by inhibiting neutrophil elastase. Approximately 1 in 2750 to 1 in 4500 individuals have an autosomal codominant condition that leads to a deficiency of circulating AAT. In individuals with AAT deficiency (AATD), AAT is retained in liver cells, which predisposes them to liver disease, and does not reach lung tissues through circulation, where it normally acts as the primary natural regulator of proteolytic activity in the pulmonary tissues, which thus leads to lung disease. Despite being commonly labeled as a rare disease, AATD is one of the most common autosomal genetic disorders and is considered highly underrecognized, with ≤10% of individuals suspected with AATD identified. Screening guidelines have been established, and the diagnosis is easy to confirm when the condition is suspected. Early recognition is key to prevent morbidity and mortality associated with the disease. For this reason, all patients with chronic obstructive pulmonary disease and patients with asthma and fixed obstruction should be tested to exclude the diagnosis of AATD. Augmentation therapy of the deficient protein is available for those with significant lung disease and protein deficiency, and analysis of recent data supported preservation of lung tissue with this treatment. In this review, oriented toward specialists in allergy and immunology, we focused our discussion on the presentation, diagnosis, and treatment of pulmonary symptoms of AATD.

Astragalin Inhibits Allergic Inflammation and Airway Thickening in Ovalbumin-Challenged Mice

Lung inflammation and oxidative stress are the major contributors to the development of obstructive pulmonary diseases. Macrophages are involved in pulmonary inflammation and alveolar damage in emphysema. Astragalin is an anti-inflammatory flavonoid present in persimmon leaves and green tea seeds. This study elucidated that astragalin inhibited inflammatory cell infiltration induced by 20 μM H₂O₂ and blocked airway thickening and alveolar emphysema induced by 20 μg of ovalbumin (OVA) in mice. OVA induced mouse pulmonary MCP-1, and H₂O₂ enhanced the expression of MCP-1/ICAM-1/αv integrin in bronchial airway epithelial BEAS-2B cells. Such induction was inhibited by supplying 10-20 mg/kg of astragalin to OVA-challenged mice and 1-20 μM astragalin to oxidant-stimulated cells. Oral administration of 20 mg/kg of astragalin reduced the induction of F4/80/CD68/CD11b in airways of mice challenged with OVA. Additionally, emphysema tissue damage was observed in OVA-exposed alveoli. Mast cell recruitment in the airway subepithelium was blocked by supplementing astragalin to OVA-challenged mice. Orally treating 20 mg/kg of astragalin reduced α-SMA induction in inflammation-occurring airways and appeared to reverse airway thickening and constriction induced by an OVA episode. These results revealed that astragalin may improve airway thickening and alveolar destruction with blockade of allergic inflammation in airways. Therefore, astragalin may be a therapeutic agent antagonizing asthma and obstructive pulmonary diseases.

The Microenvironment of Lung Cancer and Therapeutic Implications

The tumor microenvironment (TME) represents a milieu that enables tumor cells to acquire the hallmarks of cancer. The TME is heterogeneous in composition and consists of cellular components, growth factors, proteases, and extracellular matrix. Concerted interactions between genetically altered tumor cells and genetically stable intratumoral stromal cells result in an "activated/reprogramed" stroma that promotes carcinogenesis by contributing to inflammation, immune suppression, therapeutic resistance, and generating premetastatic niches that support the initiation and establishment of distant metastasis. The lungs present a unique milieu in which tumors progress in collusion with the TME, as evidenced by regions of aberrant angiogenesis, acidosis and hypoxia. Inflammation plays an important role in the pathogenesis of lung cancer, and pulmonary disorders in lung cancer patients such as chronic obstructive pulmonary disease (COPD) and emphysema, constitute comorbid conditions and are independent risk factors for lung cancer. The TME also contributes to immune suppression, induces epithelial-to-mesenchymal transition (EMT) and diminishes efficacy of chemotherapies. Thus, the TME has begun to emerge as the "Achilles heel" of the disease, and constitutes an attractive target for anti-cancer therapy. Drugs targeting the components of the TME are making their way into clinical trials. Here, we will focus on recent advances and emerging concepts regarding the intriguing role of the TME in lung cancer progression, and discuss future directions in the context of novel diagnostic and therapeutic opportunities.

Genetic association between obstructive bronchitis and enzymes of oxidative stress

OBJECTIVE

Obstructive respiratory diseases, mainly the chronic obstructive pulmonary disease (COPD) and asthma, are associated with functional polymorphisms of xenobiotic-metabolizing enzymes (XMEs). To date, association for obstructive bronchitis has not been described.

MATERIAL/METHODS

In this study, we investigated the genotypes from 26 functional polymorphisms of 20 XMEs in children (n, 1028) at the age of 6 years from the German prospective birth cohort study (LISAplus) and analyzed the associations between genotypes and obstructive bronchitis.

RESULTS

For the first time, we found noteworthy gene-disease associations for the functional PON1 M55L and EPHX1 H139R polymorphisms and gene-environment associations for the functional COMT V158M and NQO1 P187S polymorphisms after stratification for maternal active smoking behaviour during pregnancy. The noteworthy associations were substantiated by the biological findings that all the risk genotypes belong to genes involved in oxidative stress and code for proteins with a fast enzymatic activity or concomitantly appear in common estrogene-metabolizing pathway (COMT, NQO1).

CONCLUSION

The oxidative stress has to be taken into account in mechanism of the obstructive bronchitis in early childhood. The risk genotypes may serve as risk factors for respiratory obstruction rather than for signs of COPD or asthma.

Leukotriene C4 synthase and ischemic cardiovascular disease and obstructive pulmonary disease in 13,000 individuals

Ischemic cardiovascular disease and obstructive pulmonary disease involve inflammation. Leukotrienes may be important pro-inflammatory mediators. We tested the hypothesis that the (-1072)G > A and (-444)A > C promoter polymorphisms of leukotriene C4 synthase confer risk of transient ischemic attack (TIA), ischemic stroke, ischemic heart disease (IHD), asthma, and chronic obstructive pulmonary disease (COPD). We genotyped individuals from the Danish general population, the Copenhagen City Heart Study, and Danish patients with IHD/coronary atherosclerosis, the Copenhagen Ischemic Heart Disease Study. We used prospective (n = 10,386), cross-sectional (n = 10,386), and case-control (n = 2392 + 5012) designs. Allele frequency was 0.07 for (-1072)A and 0.29 for (-444)C. Cumulative incidence for TIA was higher for (-1072)AA versus GG genotype (log-rank: p < 0.001), and lower for (-444)CC versus AA genotype (log-rank: p = 0.03). Cumulative incidence for ischemic stroke was also lower for (-444)CC versus AA genotype (log-rank: p = 0.04). Multifactorially adjusted hazard ratios for TIA were 5.2(95% CI:1.9-14) for (-1072)AA versus GG genotype, and 0.4(0.2-1.0) for (-444)CC versus AA genotype. Corresponding values were 1.9 (0.7-5.2) and 0.7 (0.5-1.0) for ischemic stroke, and 0.8 (0.4-1.6) and 1.0 (0.9-1.2) for IHD. In the case-control study, corresponding multifactorially adjusted odds ratios for IHD/coronary atherosclerosis were 0.5 (0.2-1.3) and 1.2 (1.0-1.5). These genotypes were not associated with risk of asthma or COPD. Leukotriene C4 synthase promoter genotypes influence risk of TIA and ischemic stroke, but not risk of IHD/coronary atherosclerosis, asthma, or COPD.

Sicilian family with autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED) and lethal lung disease in one of the affected brothers

INTRODUCTION

We report the clinical and immunological features of the autoimmune regulator gene (AIRE) in two Sicilian brothers with autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED). They were compound heterozygotes with R203X/R257X. Both had oral candidiasis since the first year of life and later developed hypoparathyroidism and Addison disease. The elder brother had experienced recurrent lower respiratory infections since 5 years of age and over the years developed severe obstructive lung disease with bronchiectasis, which led to death at 18 years of age. Both brothers had circulating autoantibodies against tryptophan hydroxylase and serotonin-producing cells were absent in the duodenal mucosa. This was associated with intestinal dysfunction in only the elder brother.

CONCLUSION

(1) In the first Sicilian family with APECED reported up to now we found a heterozygous mutation that had been previously reported only once. (2) In the older brother of this family we observed a severe and lethal lung disease; this case adds to a growing literature describing this association between APECED and respiratory illnesses. (3) Tryptophan hydroxylase antibodies might be hypothesized to be the marker of an autoimmune gastrointestinal illness possibly associated with APECED.

[Genetics of recurrent airway obstruction (RAO)]

Recurrent airway obstruction (RAO) is a multifactorial and polygenic disease. Affected horses are typically 7 years of age or older and show exercise intolerance, increased breathing effort, coughing, airway neutrophilia, mucus accumulation and hyperreactivity as well as cholinergic bronchospasm. The environmental factors responsible are predominantly allergens and irritants in haydust, but the immunological mechanisms underlying RAO are still unclear. Several studies have demonstrated a familiar predisposition for RAO and it is now proven that the disease has a genetic basis. In offspring, the risk of developing RAO is 3-fold increased when one parent is affected and increases to almost 5-fold when both parents have RAO. Segregation analysis in two high-prevalence families demonstrated a high heritability and a complex inheritance with several major genes. A whole genomescan showed chromosome-wide significant linkage of seven chromosomal regions with RAO. Of the microsatellites, which were located near atopy candidate genes, those in a region of chromosome 13 harboring the IL4R gene were strongly associated with the RAO phenotype in the offspring of one RAO-affected stallion. Furthermore, IgE-levels are influenced by hereditary factors in the horse, and we have evidence that RAO-affected offspring of the same stallion have increased levels of specific IgE against moldspore allergens. The identification of genetic markers and ultimately of the responsible genes will not only allow for an improved prophylaxis, i.e. early identification of susceptible individuals and avoidance of high-risk matings, but also improve our ability to find new therapeutic targets and to optimize existing treatments.

Interleukin-1 gene complex polymorphisms in systemic sclerosis patients with severe restrictive lung physiology

Increased concentrations of interleukin-1 (IL-1) were observed in bronchoalveolar lavage fluids from patients with systemic sclerosis (SSc), and their levels were correlated with the patients' forced vital capacity (FVC). Because IL-1 production is regulated at the genetic level, we hypothesized that IL-1 gene complex single nucleotide polymorphisms (SNPs) might be relevant to the progression of ventilatory restriction in SSc. Two-hundred four Italian SSc patients were genotyped for the following IL-1 gene complex SNPs: IL-1alpha C-889T, IL-1beta C+3962T, IL-1beta C-511T, IL-1R Cpst1970T, and IL-1Ra Cmspal11100T, as well as for the following SNPs of cytokines with regulatory functions on IL-1 production: IFNgamma AUTR5644T, TNFalpha A-308G, and IL-10 A-1082G. The SNPs were inserted in a Cox regression model with disease subset, gender, autoantibodies, age at onset of disease, and prior use of immunosoppresants as covariates and the presence of FVC<55% of predicted values as outcome measure; p values were corrected for the number of pairwise comparisons. Twenty-five patients (12.3%) developed a severe ventilatory restriction after 6.8+/-6.6 years (mean+/-standard deviation) from diagnosis. In our model, the relative risk to develop a severe ventilatory restriction was increased by the antitopoisomerase I antibody (p=0.01; HR=14.67, CI95=1.87-114.92), the dcSSc subset (p=0.007; HR=3.14, CI95=1.36-7.21) and the IL-1beta C+3962T SNP (p=0.003 TT vs CC; HR=6.61, CI95=2.28-19.15). The IL-1beta C+3962T SNP is associated with the presence of severe restrictive lung physiology in Italian SSc patients.

Pulmonary involvement in systemic sclerosis: associations with genetic, serologic, sociodemographic, and behavioral factors

OBJECTIVE

To determine the relative contributions of genetic, clinical, serologic, sociodemographic, and behavioral/psychological variables to early pulmonary involvement in the Genetics versus Environment in Scleroderma Outcome Study cohort.

METHODS

At the baseline visit (V0), 203 patients with systemic sclerosis (SSc) were examined (104 whites, 39 African Americans, and 60 Hispanics). We obtained sociodemographic, behavioral/psychological (illness behavior, social support, learned helplessness, smoking, drinking), clinical, serologic (autoantibodies), and genetic (HLA class II and FBN1 genotypes) factors; pulmonary function test results; electrocardiograms; and chest radiographs. Data analysis included Fisher's exact test, chi-square test, Student's t-test, analysis of variance, and stepwise linear and logistic regression methods.

RESULTS

Significant pulmonary involvement was seen in 25% of patients within 2.8 years of SSc diagnosis. At V0, pulmonary fibrosis was significantly higher in African Americans compared with whites or Hispanics. African Americans had significantly lower percent predicted forced vital capacity (FVC) and forced expiratory volume in 1 second (FEV(1)) compared with whites and significantly lower percent predicted diffusing capacity for carbon monoxide (DLCO) compared with whites and Hispanics. Significant, independent associations impacting early pulmonary involvement included African American ethnicity, skin score, serum creatinine and creatine phosphokinase values, hypothyroidism, and cardiac involvement. Anticentromere antibody seropositivity was a significant, independent, protective factor for restrictive lung disease and FVC or DLCO values. African Americans had significantly increased frequencies of anti-topoisomerase I, fibrillarin, and RNP autoantibodies compared with whites. African Americans scored significantly lower on the Interpersonal Support Evaluation List and significantly higher on the Illness Behavior Questionnaire.

CONCLUSION

Early pulmonary involvement in SSc appears to be influenced by several factors delineated by ethnicity, including racial, socioeconomic, behavioral, and serologic determinants.

ETB receptor polymorphism is associated with airway obstruction

Background

Endothelin-1 (EDN1) has been involved in the development of airway obstruction and inflammation in asthma. Several polymorphisms have been identified among the genes encoding for preproET1, an inactive precursor of ET-1, and for ET_A (EDNRA) and ET_B (EDNRB), the two receptors for EDN1. In the present work, we hypothesised that molecular variation in these genes could be a major determinant of the degree of bronchial obstruction. The purpose of this study was to investigate whether the genetic polymorphisms of preproET-1, EDNRA and EDNRB genes were associated with the degree of airway obstruction, assessed by FEV₁.

Methods

Polymorphisms of preproET-1, EDNRA and EDNRB were first studied in a population of adult asthmatic patients. Results were confirmed in a large population of adults from the general population from the ECRHS II study.

Results

In our population of adult asthmatic patients, the EDNRB-30G>A (Leu277Leu) polymorphism (GG genotype) is strongly associated with a low FEV₁ and with a higher percentage of patients with FEV1 < 80% of predicted value. No relationship was found between pulmonary function and EDNRA-1363C>T (His323His) or preproET-1-595G>T (Lys198Asp) polymorphism. In the adult population from the ECRHS II, we found a similar association between GG genotype and a low FEV₁ or a higher percentage of subjects with FEV1 < 80% predicted, especially in the subgroups of asthmatics subjects (OR = 4.31 (95%CI 1.03 – 18.04)) and smokers (OR = 7.42 (95%CI 1.69 – 32.6)).

Conclusion

the EDNRB-30G>A polymorphism could be a determinant of airway obstruction in humans with predisposing factors such as tobacco smoke exposure or asthma.

The chemokine receptor D6 has opposing effects on allergic inflammation and airway reactivity

RATIONALE

The D6 chemokine receptor can bind and scavenge several chemokines, including the T-helper 2 (Th2)-associated chemokines CCL17 and CCL22. Although D6 is constitutively expressed in the lung, its pulmonary function is unknown.

OBJECTIVES

This study tested whether D6 regulates pulmonary chemokine levels, inflammation, or airway responsiveness during allergen-induced airway disease.

METHODS

D6-deficient and genetically matched C57BL/6 mice were sensitized and challenged with ovalbumin. ELISA and flow cytometry were used to measure levels of cytokines and leukocytes, respectively. Mechanical ventilation was used to measure airway reactivity.

RESULTS

The ability of D6 to diminish chemokine levels in the lung was chemokine concentration dependent. CCL17 and CCL22 were abundant in the airway, and their levels were attenuated by D6 when they were within a defined concentration range. By contrast, airway concentrations of CCL3, CCL5, and CCL11 were low and unaffected by D6. Allergen-challenged D6-deficient mice had more dendritic cells, T cells, and eosinophils in the lung parenchyma and more eosinophils in the airway than similarly challenged C57BL/6 mice. By contrast, D6-deficient mice had reduced airway responses to methacholine compared with C57BL/6 mice. Thus, D6 has opposing effects on inflammation and airway reactivity.

CONCLUSIONS

The ability of D6 to scavenge chemokines in the lung is dependent on chemokine concentration. The absence of D6 increases inflammation, but reduces airway reactivity. These findings suggest that inhibiting D6 function might be a novel means to attenuate airway responses in individuals with allergic asthma.

Mucin overproduction in chronic inflammatory lung disease

Mucus overproduction and hypersecretion are commonly observed in chronic inflammatory lung disease. Mucins are gel-forming glycoproteins that can be stimulated by a variety of mediators. The present review addresses the mechanisms involved in the upregulation of secreted mucins. Mucin induction by neutrophil elastase, bacteria, cytokines, growth factors, smoke and cystic fibrosis transmembrane conductance regulator malfunction are also discussed.

Allele-specific binding of airway nuclear extracts to polymorphic beta2-adrenergic receptor 5' sequence

Like other intronless G protein-coupled receptor genes, the beta(2)-adrenergic receptor (beta(2)AR) has minimal genetic space for population variability, and has attained such via multiple coding and noncoding polymorphisms. Yet most clinical studies use the two nonsynonymous polymorphisms of the coding region for association analysis despite low levels of linkage disequilibrium with some promoter and 5'UTR polymorphisms. To assess the potential for allele-specific transcription factor binding to beta(2)AR 5'-flanking sequence, 3'-biotin-labeled oligonucleotide duplexes were synthesized. Each was centered on variable sites representing major or minor alleles found in the human population with frequencies of 5% or greater (20 polymorphic sites). Electrophoretic mobility shift assays were performed using human airway smooth muscle or airway epithelial cell nuclear extracts. Many of these polymorphisms resulted in an alteration in binding, and both major allele and minor allele dominance were observed. For example, in airway smooth muscle nuclear extracts, 10 polymorphisms decreased and 2 increased binding, whereas 5 showed no differences. Concordance between airway smooth muscle and epithelial cell nuclear extract binding to polymorphic alleles was found in only approximately 50% of cases. There was no tendency for the rare variants to be more likely to have altered nuclear extract binding compared to the more common variants. Taken together, these results provide potential mechanisms by which beta(2)AR 5'-flanking polymorphisms affect obstructive lung phenotypes.

AluyMICB dimorphism within the class I region of the major histocompatibility complex is associated with asthma and airflow obstruction in the Busselton population

AIM

To examine the association between the Alu dimorphism within the first intron of the MICB gene and asthma and airflow obstruction. Background The highly polymorphic non-classical MHC class I polypeptide-related (MIC) genes, MICA and MICB, encode stress inducible glycoproteins, which are expressed on a variety of epithelial cells, including those of the lungs.

METHODS

AluyMICB genotyping was performed on 1109 subjects from the Busselton Health Study. From a standard questionnaire, 359 individuals indicated that they had been diagnosed by a doctor with asthma. Lung function was assessed by the forced expired volume in 1 second (FEV1) and expressed as a percent of the predicted value. Airflow obstruction was defined as FEV1<80% predicted.

RESULTS

In men, a dominant relationship was found between the AluyMICB DD genotype and asthma (P=0.006; chi2(2)=7.65). Furthermore, multivariate analysis adjusted for age, height, weight and body mass index (BMI) showed a relationship between DD genotype and asthma in men in a dominant model (odds ratio (OR)=1.97; 95% confidence interval (CI)=1.11-3.51; P=0.021). In women, an association was found between the AluyMICB II genotype and FEV1 percent predicted as a continuous variable (P=0.001). When adjusted for age and BMI, it showed a significant relationship between AluyMICB and airflow obstruction in a dominant model (OR=14.11%, 95% CI 3.29-60.57, P<0.001). However, no association was found between the AluyMICB II genotypes and airflow obstruction in men.

CONCLUSION

These findings suggest the possible involvement of a MHC class I gene in abnormal airway structure in women and airway function in men.

DNA binding activity of transcription factors in bronchial cells of horses with recurrent airway obstruction

Horses with recurrent airway obstruction (RAO) present many similarities with human asthmatics including airway inflammation, hyperresponsiveness, reversible obstruction, and increased NF-kappaB expression. Studies in experimental asthma models have shown that transcriptions factors such as activator protein-1 (AP-1), GATA-3, cyclic AMP response element binding protein (CREB) and CAAT/enhancer binding protein (C/EBP) may also play an important role in airway inflammation. The purpose of this study was to measure DNA binding activity of these transcription factors in the airways of horses with RAO and to compare it to pulmonary function and bronchoalveolar lavage fluid (BALF) cytology. Seven horses with RAO and six control animals were studied during a moldy hay challenge and after 2 months at pasture. Pulmonary function, BALF cytology and transcription factors' activities in bronchial brushings were measured during hay and pasture exposures. During moldy hay challenge, RAO-affected horses developed severe airway obstruction and inflammation and a significantly higher airway AP-1 binding activity than in controls. After 2 months on pasture, pulmonary function and airway AP-1 binding activity were not different between RAO and control horses. The DNA binding activity of CREB in airways of RAO-affected horses increased significantly after 2 months at pasture and became higher than in controls. A significant positive correlation was detected between AP-1 binding activity and indicators of airway obstruction and inflammation. Airway GATA-3, CEBP and CREB binding activities were negatively correlated with indices of airway obstruction. However, contrarily to CREB binding activity, GATA-3 and CEBP binding activities were not different between RAO and control horses and were unaffected by changes in environment. These data support the view that AP-1 and CREB play a role in modulating airway inflammation in horses with RAO.

IL-4, IL-5 and IFN-gamma mRNA expression in pulmonary lymphocytes in equine heaves

Heaves is a common condition of horses of cold climate that is characterized by small airway inflammation and obstruction following exposure of susceptible horses to moldy hay and straw. It has been shown that helper T lymphocytes (Th) orchestrate the inflammatory response in asthma and in various animal models of allergic lung diseases by the release of Th2-type cytokines. Results of previous studies indicate that a predominant expression of Th2-type response by airway cells may also be present in heaves. To evaluate the temporal mRNA expression of Th1 (IFN-gamma) and Th2 (IL-4, IL-5) type cytokines in heaves and their relationship to clinical disease, we studied the pulmonary mechanics and cytokine mRNA expression (IL-4, IL-5 and IFN-gamma) in bronchoalveolar lavage lymphocytes of horses with heaves (n=6) and control (n=6) before and after 24h and 9 days of continuous natural inhalation challenge. Starting 24h after challenge horses with heaves, but not control horses, had a significant increase in pulmonary elastance and the number of lymphocytes expressing mRNA for IL-4 and IL-5. These changes were further increased at 9 days, at which time the number of cells positive for IFN-gamma mRNA was decreased. In this study we have shown that BAL lymphocytes of horses with heaves during clinical exacerbation have a predominant Th2-type cytokine response and that this response coincides in time with the presence of airway obstruction.

Associations between polymorphisms of the high-affinity immunoglobulin E receptor and late-onset airflow obstruction in older populations

OBJECTIVES

To test the hypothesis that genetic polymorphisms in the beta subunit of the high-affinity immunoglobulin E (IgE) receptor are associated with late-onset airflow obstruction.

DESIGN

Case-control candidate gene association study.

SETTING

Department of Medicine for the Elderly and Respiratory Medicine in three teaching hospitals in Leicester and Manchester, United Kingdom.

PARTICIPANTS

Cases with late-onset airflow obstruction with age-, sex-, and geographically matched controls.

MEASUREMENTS

Subjects were genotyped for two polymorphisms of the beta subunit of the high-affinity IgE receptor (RsaI intron 2 and RsaI exon 7). The association between the polymorphisms and phenotypes was examined using contingency tables and linear regression models.

RESULTS

Two hundred eighty-three cases and 144 controls were genotyped. RsaI exon 7 AA was associated with eczema (odds ratio (OR)=2.27, 95% confidence interval (CI)=1.17-4.38, P=.015). No other associations were found. Total serum IgE levels were significantly higher in cases than controls (adjusted OR for high/low IgE=2.56, 95% CI=1.53-4.28, P<.001).

CONCLUSION

Serum IgE levels, but not the high-affinity IgE receptor polymorphisms, were associated with late-onset airflow obstruction, suggesting that interaction between environmental and genetic factors controlling serum IgE levels and disease pathogenesis may differ between early- and late-onset airflow obstruction phenotypes.

Upper airway malformation associated with partial trisomy 11q

11q trisomy is associated with a recognizable pattern of multiple malformations. Review of the literature reveals the following recurrent themes common to complex and isolated 11q trisomy: mental retardation, pre- and postnatal growth retardation, hypotonia, a distinct pattern of facial features, congenital heart defects, and limb malformations. We report four patients with partial trisomy 11q, none of which arose from the common 11/22 translocation. Three of the four patients had the previously unreported finding of upper airway obstruction secondary to a malformed epiglottis. The critical region for this malformation appears to be 11q21-23.2.

[Clinical polymorphism in respiratory oxalosis]

AIM

Examination of clinical polymorphism of chronic obstructive pulmonary diseases (COPD) in defects of oxalate metabolism to make diagnostic outpatient screening of the preclinical stage.

MATERIAL AND METHODS

Diagnostic dysgenetic markers of respiratory oxalosis (RO)--red hair in monthers and 24-h oxaluria--were studied in 28 women and 7 men. 8 women (group 1) had diagnostic association, 7 women (group 2) had no hereditary marker, 13 women (group 3) had no signs of disturbed oxalate metabolism. In addition, families of group 1 patients were examined for preclinical signs of visceral oxalosis in close relatives (kinship degree I). A comparison was made of quantitative enzyme assay of registering 24-h oxaluria (Lartillot M. et Vogel G) and titration by G. A. Sivorinovsky.

RESULTS

Group 1 COPD patients with mild disease had rather high 24-h oxaluria. In group 2 and 3 patients oxaluria was significantly lower. Dysgenetic markers--24-h oxaluria with the hereditary criterium--may be used in differential diagnosis of RO with its phenocopy having a more severe course at preclinical stage. Male relatives of kinship degree I had significant differences with group 1 patients in 24-h oxaluria, oxaluria was combined with clinical symptoms of acid, uratic diathesis.

CONCLUSION

The enzyme assay of oxalate in 24-h urine in combination with hereditary marker is an adequate screening method for preclinical stage of RO. The presence of various clinical manifestations of visceral oxalosis--RO and acid, uratic diathesis in the family--may indicate clinical polymorphism of mutant gene.

[Prognostication of obstructive syndrome in patients with chronic bronchitis considering hereditary factors]

AIM

To propose method of accurate prediction of chronic obstructive pulmonary disease (COPD) at early stages of development.

MATERIAL AND METHODS

92 males with COPD and 55 males with chronic non-obstructive bronchitis aged 38 to 72 years were examined according to a technique which identifies hereditary predisposition to multifactor diseases and using an algorithm based on multivariate analysis.

RESULTS

An original mathematical model is proposed which can quantitatively examine and range by influence the role of environmental and hereditary factors in development of COPD.

CONCLUSION

Detection of hereditary predisposition to COPD may be one of the objective criteria to recommend giving up smoking and for occupational orientation.

Pilot detection study of alpha(1) antitrypsin deficiency in a targeted population

Screenings for the genetic disorder alpha(1) antitrypsin deficiency (AAT Deficiency) have been one of two models: large screenings of general populations and small targeted detection programs in high-risk groups. The most appropriate screening and detection methodologies in terms of target populations, subject participation and yield of positive tests, however, have not been well defined. The major objective of this pilot study was to evaluate the effectiveness in terms of participation of two different AAT Deficiency detection programs using a self-administered fingerstick blood test. Individuals ages 30-60 under the care of a pulmonary physician and with a diagnosis of emphysema, COPD, chronic bronchitis, or bronchiectasis were the targeted population. Participants were offered AAT Deficiency testing in the pulmonary physician's office compared with testing offered through mail. Participation (i.e., frequency of subject participation in the detection program) of two different AAT Deficiency detection programs. Non-participation was due to fear of self-administered testing and research studies; women were more likely to participate than men. Eligible subjects were significantly more likely to participate when offered testing by their pulmonary physician in-office (83%) than mail-only (42%) (P < 0.02). Although self-administered genetic testing is available, highest participation in AAT Deficiency detection program was found when offered directly by the physician. This finding may have implications for screening and detection of other genetic diseases. Future studies need to evaluate the yield (i.e., frequency of positive tests) of these detection methodologies in highly targeted populations.

Oxidants/antioxidants and chronic obstructive pulmonary disease: pathogenesis to therapy

There is now considerable evidence for an increased oxidant burden in smokers, particularly in those smokers who develop chronic obstructive pulmonary disease (COPD), as shown by increased markers of oxidative stress in the airspaces, breath, blood and urine. The presence of increased oxidative stress is a critical feature in the pathogenesis of COPD, since it results in inactivation of antiproteinases, airspace epithelial injury, mucus hypersecretion, increased sequestration of neutrophils in the pulmonary microvasculature, and gene expression of pro-inflammatory mediators. The sources of the increased oxidative stress in patients with COPD derive from the increased burden of oxidants present in cigarette smoke, or from the increased amounts of reactive oxygen species released from leukocytes, both in the airspaces and in the blood. Antioxidant depletion or deficiency in antioxidants also contributes to oxidative stress. The development of airflow limitation is related to dietary deficiency of antioxidants and hence dietary supplementation may be a beneficial therapeutic intervention in this condition. Oxidative stress also has a role in enhancing the airspace inflammation, which occurs in smokers and patients with COPD through the activation of redox-sensitive transcriptions factors such as NF-kappa B and AP-1, which regulate the genes for pro-inflammatory mediators and protective antioxidant gene expression. Antioxidants that have good bioavailability or molecules that have antioxidant enzyme activity are therefore therapies that not only protect against the direct injurious effects of oxidants, but also may fundamentally alter the inflammatory events which have a central role in the pathogenesis of COPD.

Genetics of chronic obstructive pulmonary disease

The marked variability in the development of chronic obstructive pulmonary disease (COPD) in response to cigarette smoking has been known for decades, but severe alpha 1-antitrypsin deficiency (PI Z) remains the only proven genetic risk factor for COPD. With cigarette smoking, PI Z subjects tend to develop more severe pulmonary impairment at an earlier age than non-smoking PI Z individuals. However, PI Z individuals exhibit wide variability in pulmonary function impairment, even among individuals with similar smoking histories. Therefore, other genes and environmental exposures are also likely involved. The role of heterozygosity for the Z allele as a risk factor for COPD remains controversial, but accumulating evidence suggests that at least some PI MZ individuals are at increased risk of developing airflow obstruction. In individuals without alpha 1-antitrypsin deficiency, familial aggregation of COPD has been reported in several studies. To study novel genetic determinants of COPD, our research group enrolled 44 severe, early-onset COPD probands (FEV1 < 40%, age < 53 yrs, non-PI Z) and 266 of their relatives. A marked female predominance was noted among the early-onset COPD probands. In addition, increased risk to current or ex-smoking first-degree relatives of early-onset COPD probands for reduced FEV1, chronic bronchitis and spirometric bronchodilator responsiveness has been demonstrated. These data strongly support the genetic basis for the development of COPD and the potential for gene-by-environment interaction. A variety of studies have examined candidate gene loci with association studies, comparing the distribution of variants in genes hypothesized to be involved in the development of COPD in COPD patients and control subjects. For most genetic loci which have been tested, there have been inconsistent results. Genetic heterogeneity could contribute to difficulty in replicating associations between studies. In addition, case-control association studies are susceptible to supporting associations based purely on population stratification, which can result from incomplete matching between cases and controls--including differences in ethnicity. No association studies in COPD have been reported which used family-based controls, a study design which is immune to such population stratification effects. More importantly, no linkage studies have been published in COPD to identify regions of the genome which are likely to contain COPD susceptibility genes--regions in which association studies are likely to be more productive.

CFTR gene mutations--including three novel nucleotide substitutions--and haplotype background in patients with asthma, disseminated bronchiectasis and chronic obstructive pulmonary disease

In order to investigate the incidence of cystic fibrosis transmembrane conductance regulator (CFTR) gene mutations and unclassified variants in chronic pulmonary disease in children and adults, we studied 20 patients with asthma, 19 with disseminated bronchiectasis (DB) of unknown aetiology, and 12 patients with chronic obstructive pulmonary disease (COPD), and compared the results to 52 subjects from the general Greek population. Analysis of the whole coding region of the CFTR gene and its flanking intronic regions revealed that the proportion of CFTR mutations was 45% in asthma (P<0.05), 26.3% in DB (P>0.05), 16.7% in COPD (P>0.05), compared to 15.4% in the general population. Seventeen different molecular defects involved in disease predisposition were identified in 16 patients. Three potentially disease-causing mutations, T388 M, M1R and V11I, are novel, found so far only in three asthma patients. The hyperactive M470 allele was found more frequently in COPD patients (frequency 70.8%, P<0.01) than in the controls. The study of the TGmTnM470 V polyvariant CFTR allele revealed the presence of CFTR function-modulating haplotypes TG13/T5/M470, TG11/T5/M470, TG12/T5/V470 and TG12/T7, combined with M470 or V470, in six asthma patients, four DB patients (P<0.01), and two COPD patients (P<0.05). These results confirm the involvement of the CFTR gene in asthma, DB and possibly in COPD.

[Genetic variation of NADPH/NADH oxidase and susceptibility to diffuse panbronchiolitis (DPB) and chronic obstructive pulmonary disease (COPD)]

Diffuse panbronchiolitis (DPB) and chronic obstructive pulmonary disease (COPD) are both characterized by chronic airflow obstruction of unknown etiology. It is hypothesized that neutrophils play the major role in the pathogenesis of these diseases. Recent studies have suggested that genetic factors may be related to individual susceptibility to these diseases. We have investigated the association between the C 242 T polymorphism of p 22 phox, a critical subunit of superoxide-generating NADH/NADPH oxidase, and susceptibility to DPB and COPD. Blood samples obtained from both patients with DPB (n = 82), COPD (n = 53), and control subjects (n = 82) were used for this genotyping assay; and the polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) were performed to genotype the gene. The frequency of the C allele was 0.91, 0.92, 0.92 in the DPB, COPD, and control groups, respectively. There were no differences in the distribution of the genotype of p 22 phox among these groups, either. We concluded that there is no association between the C 242 T polymorphism of p 22 phox, and susceptibility to DPB and COPD.

Fifteen-year follow-up of pulmonary function in individuals heterozygous for the cystic fibrosis phenylalanine-508 deletion

BACKGROUND

In a cross-sectional study, we previously showed that cystic fibrosis phenylalanine-508 deletion (DeltaF508) heterozygosity may be overrepresented among individuals with asthma.

OBJECTIVE

Using 15-year follow-up data from the Copenhagen City Heart Study, we now further explore this relationship.

METHODS

As part of 3 surveys in 1976 to 1978, 1981 to 1983, and 1991 to 1994, we measured pulmonary function and asked all participants about asthma and pulmonary risk factors.

RESULTS

There was no difference in annual decline in lung function between DeltaF508 heterozygotes and noncarriers overall; however, among individuals with familial asthma, the annual declines in FEV(1) and forced vital capacity (FVC) were 49 and 36 mL in DeltaF508 heterozygotes versus 24 and 17 mL in noncarriers (P =.01 and P =.12, respectively). Cross-sectionally based on triple measurements, FEV(1) and FVC in individuals aged 20 to 70 years were lower in heterozygous participants versus noncarriers (P =.02 and P =.004, respectively). The average reduction of FEV(1) and FVC in DeltaF508 heterozygotes versus noncarriers was 70 mL (P =.06) and 136 mL (P =.008). Finally, 10% of carriers reported asthma versus 7% of noncarriers (P =.02), resulting in an odds ratio of 2.0 (1.3-3.2) for asthma in DeltaF508 heterozygotes.

CONCLUSION

Cystic fibrosis DeltaF508 heterozygotes may be overrepresented among individuals with asthma and may have poorer lung function than noncarriers. Furthermore, DeltaF508 heterozygosity in context with familial predisposition to asthma may be associated with a greater annual FEV(1) decline.

Susceptibility genes for rapid decline of lung function in the lung health study

The genes that contribute to the genetic susceptibility to chronic obstructive pulmonary disease (COPD) remain largely unknown. We hypothesized that widely divergent rates of decline in lung function in smokers would be a robust phenotype for detection of genes that contribute to COPD severity. We selected 283 rapid decliners (deltaFEV1 = -154 +/- 3 ml/yr) and 308 nondecliners (deltaFEV1 = +15 +/- 2 ml/yr) from among smokers followed for 5 yr in the NHLBI Lung Health Study. Rapid decline of FEV1 was associated with the MZ genotype of the alpha1-antitrypsin gene (odds ratio [OR] = 2.8, p = 0.03). This association was stronger for a combination of a family history of COPD with MZ (OR = 9.7, p = 0.03). These data suggest that the MZ genotype results in an increased rate of decline in lung function and interacts with other familial factors. Haplotype frequencies of the microsomal epoxide hydrolase (mEH) gene were significantly different between rapid decliners and nondecliners (p = 0.03). A combination of a family history of COPD with homozygosity for the His113/His139 mEH haplotype was also associated with rapid decline of lung function (OR = 4.9, p = 0.04). The alpha1-antitrypsin S and 3' polymorphisms, vitamin D-binding protein isoforms, and tumor necrosis factor (TNF-alpha G-308A and TNF-beta A252G) polymorphisms were not associated with rate of decline of lung function.

Association of tumor necrosis factor alpha gene promoter polymorphism with the presence of chronic obstructive pulmonary disease

Tumor necrosis factor alpha (TNF-alpha), a potent proinflammatory cytokine, may be involved in the development of chronic obstructive pulmonary disease (COPD). The production of TNF-alpha is elevated in the airways of these patients. A polymorphism at position -308 of the TNF-alpha gene promoter (TNF-alpha-308*1/2) is known to be associated with alteration of TNF-alpha secretion in vitro. In this study we examined the differences in TNF-alpha-308*1/2 allele frequency to investigate the association of this polymorphism with the presence of smoking-related COPD. TNF-alpha-308*1/2 allele frequency in 106 patients (73 men and 33 women) was compared with 110 asymptomatic smoker/ex-smoker control subjects matched for sex and age and population control subjects consisting of 129 blood donors. Genotype was analyzed by the polymerase chain reaction-restriction fragment length polymorphism technique on genomic DNA isolated from peripheral blood lymphocytes. TNF-alpha-308*1/2 allele frequencies were significantly different among the groups: 0.835/0.165 in patients with COPD, 0.918/0.082 in smoker/ex-smoker control subjects, and 0.922/0.078 in population control subjects. These results indicate that TNF-alpha-308*1/2 alleles are significantly associated with the presence of smoking-related COPD.

Molecular diagnosis of intermediate and severe alpha(1)-antitrypsin deficiency: MZ individuals with chronic obstructive pulmonary disease may have lower lung function than MM individuals

BACKGROUND

We tested whether intermediate (MZ, SZ) and severe (ZZ) alpha(1)-antitrypsin deficiency affects lung function in the population at large.

METHODS

We performed spirometry [forced expiratory volume in 1 s (FEV(1)) and forced vital capacity (FVC)] and genotyping of 9187 individuals from the adult general population of Copenhagen, Denmark.

RESULTS

As expected, the frequencies of individuals with MM, MS, SS, MZ, SZ, and ZZ genotypes were 0.891, 0.054, 0.001, 0.052, 0.001, and 0.001, respectively. Genotype interacted with clinically established chronic obstructive pulmonary disease (COPD) on the percentage of the predicted FEV(1) (P = 0. 004): the percentage of the predicted FEV(1) was reduced in MZ compared with MM individuals among those with clinically established COPD, but not among those without COPD. Furthermore, SZ compound heterozygotes had lower FEV(1)/FVC ratios than MM individuals (P <0.05), and ZZ homozygotes had lower percentages of the predicted FEV(1) and FEV(1)/FVC ratios than MM, MS, SS, and MZ individuals (all Ps <0.01). Reduced lung function in SZ and ZZ vs MM individuals could be demonstrated in current and ex-smokers, but not in nonsmokers. Compared with MM individuals in the same groups, FEV(1) was reduced 655 mL in MZ individuals with clinically established COPD, 364 mL in SZ current smokers, and 791 mL in ZZ current smokers.

CONCLUSIONS

In the population at large, MZ was associated with reduced pulmonary function in individuals with clinically established COPD, whereas SZ and ZZ were associated with reduced pulmonary function in smokers. The presence of the alpha(1)-antitrypsin MZ genotype may in certain circumstances produce marked aggravation of airway obstruction in individuals prone to develop COPD.

Genetic risk factors for chronic obstructive pulmonary disease

Numerous epidemiologic studies have indicated that there is a genetic basis to COPD. This result suggests that COPD develops in genetically susceptible individuals after sufficient exposure to cigarette smoke. At present, most of the genes that contribute to the genetic component to COPD are unknown. alpha 1-Antitrypsin deficiency is clearly a risk factor for COPD, but the other genetic associations with this disease must be considered as tentative. The key to establishing that a gene modifies the risk for a disease is replication of the association in different populations. This is a difficult task, however, because different genetic risk factors may be present in different populations. In addition, these genetic factors may interact with each other and with environmental risk factors, obscuring the effect of the gene on the phenotype. Apart from alpha 1-AT only the GST-M1, VDBP and CFTR genes have been implicated as risk factors in more than one population. Identification of other candidate genes awaits further understanding of the pathogenesis of COPD at the molecular level. There is good evidence that the propensity to smoke cigarettes and the likelihood of quitting smoking are influenced by genetic factors. This information may be useful in efforts directed toward cessation; however, most of the genetic studies so far have shown a rather small effect. The responses to hypoxia and hypercapnia also seem to be influenced by genetic factors. Identification of the genes involved could yield important insights into the pathogenesis of COPD and may highlight new targets for therapeutic intervention for this debilitating disease.

Deletion polymorphisms in the angiotensin converting enzyme gene are associated with pulmonary hypertension evoked by exercise challenge in patients with chronic obstructive pulmonary disease

Angiotensin converting enzyme (ACE) plays an important role in the pathogenesis of pulmonary hypertension. In this study we determined whether the deletion (D)/insertion (I) polymorphism in the ACE gene may be associated with pulmonary hypertension evoked by exercise challenge in patients with chronic obstructive pulmonary disease (COPD). ACE genotypes were determined in 19 patients with COPD. All patients underwent right heart catheterization followed by a constant-load exercise test while breathing room air or oxygen. Subgroups were created of seven patients with the II genotype, six with the ID genotype, and six with the DD genotype who were well-matched with respect to age, blood gas data at rest or after exercise, baseline lung function, results of incremental exercise testing, and hemodynamic data at rest. The mean pulmonary arterial pressure (Ppa) and pulmonary vascular resistance (Rpv) at rest in the three subgrpoups did not differ significantly during breathing of either room air or oxygen. However, the Ppa after exercise challenge in patients with the DD genotype (55.7 +/- 4.9 mm Hg [mean +/- SD]) was significantly higher than in patients with the II genotype (42.6 +/- 7.1 mm Hg, p = 0.008). The Rpv after exercise in patients with the DD genotype was also significantly higher than in patients with the ID and II genotypes. During breathing of oxygen to diminish acute hypoxic pulmonary vasoconstriction, the Ppa in patients with the DD genotype (52.3 +/- 3.1 mm Hg) was higher than in patients with the ID genotype (40.5 +/- 5.9 mm Hg, p = 0.0049) or the II genotype (37.7 +/- 5.9 mm Hg, p = 0.0027). In addition, the Rpv in patients with the DD genotype was higher than in patients with the ID and II genotypes. These results suggest that D-I polymorphism in the ACE gene may be associated with pulmonary hypertension evoked by exercise challenge in patients with COPD. However, the number of patients in this study was very small for a genetic association study, and our results should be examined in larger studies.

A polymorphism in the tumor necrosis factor-alpha gene promoter region may predispose to a poor prognosis in COPD

STUDY OBJECTIVES

To determine whether the adenine (A)-guanine (G) substitution polymorphism at position - 308 on the tumor necrosis factor-alpha gene confers susceptibility to COPD or to the development of a more severe form of disease.

DESIGN

A cross-sectional study was undertaken to compare the frequency of the A allele in a group of 106 patients with COPD with that in a control population (n = 99). Patients were followed up prospectively for a period of 2 years.

PARTICIPANTS AND SETTING

Participants included 106 COPD patients recruited from a respiratory outpatient clinic and 99 control subjects recruited from patients admitted for cardiac catheterization.

MEASUREMENTS AND RESULTS

DNA was extracted from venous blood, and each subject was genotyped for the polymorphism by polymerase chain reaction amplification and restriction digestion using Nco1. There was no increased frequency of the A allele in patients compared to control subjects. AA homozygous patients had less reversible airflow obstruction (p<0.05) and a significantly greater mortality (both all-cause and respiratory deaths) on follow-up (p<0.001), despite a shorter cigarette smoking history.

CONCLUSIONS

This study suggests that homozygosity for this A allele predisposes to more severe airflow obstruction and a worse prognosis in COPD.

Neither IL-1beta, IL-1 receptor antagonist, nor TNF-alpha polymorphisms are associated with susceptibility to COPD

The cytokines that contribute to airway inflammation, including interleukin-1beta (IL-1beta) and tumour necrosis factor alpha (TNFalpha), might have key roles in the development of chronic obstructive pulmonary disease (COPD). Interleukin-1 receptor antagonist (IL-1RN), the physiological antagonist of IL-1beta, is also known to play a crucial role in several chronic inflammatory diseases. In this study, we investigated the association of the polymorphisms of IL-1beta, IL-1RN and TNFalpha with susceptibility to COPD. To elucidate the genotype of the IL-1beta polymorphisms at position -511 base and at the amino acid residue 105, the IL-1RN polymorphism in intron 2, and TNFalpha polymorphism at position -308, polymerase chain reaction (PCR) and restriction enzyme fragment length polymorphism (RFLP) were performed on blood samples from both patients with COPD (n = 53) and control subjects (n = 65). There were no differences on the allele and genotype frequency of IL-1beta, IL-1RN, and TNFalpha between the two groups. We could not find a significant link between the polymorphism of TNFalpha, which was previously reported to be associated with chronic bronchitis, and COPD. Furthermore, no association between genetic polymorphisms of IL-1beta and IL-1RN and individual susceptibility to COPD was found.

Alpha1-antitrypsin deficiency: incidence and detection program

Most individuals with AAT deficiency have escaped detection by healthcare systems worldwide. The large number of undiagnosed individuals has made it difficult to define the natural history of the clinical disease accurately, and severe ascertainment bias has colored the clinical descriptions of the disease. Most importantly, undetected individuals lose opportunities for important lifestyle changes and preventive therapies. To address this problem, the World Health Organization has recommended that all patients with chronic obstructive lung disease, and all adults and adolescents with asthma, be tested for AAT deficiency. Historically, the AAT Deficiency Detection Center has tested more than 30 000 individuals for the disease, and we have identified more than 1000 cases of AAT deficiency (approximately 30% of the known cases in the United States). Currently, we are implementing methods for determining AAT concentration (level), phenotype, and genotype in specimens of whole blood dried onto filter paper. This full spectrum of robust tests is performed on samples that are easily obtained and shipped to a central laboratory for processing. Wide application of these procedures may help to bring large numbers of presently undiagnosed patients to medical attention.

Environmental and genetic risk factors and gene-environment interactions in the pathogenesis of chronic obstructive lung disease

Current understanding of the pathogenesis of chronic obstructive pulmonary disease (COPD), a source of substantial morbidity and mortality in the United States, suggests that chronic inflammation leads to the airways obstruction and parenchymal destruction that characterize this condition. Environmental factors, especially tobacco smoke exposure, are known to accelerate longitudinal decline of lung function, and there is substantial evidence that upregulation of inflammatory pathways plays a vital role in this process. Genetic regulation of both inflammatory responses and anti-inflammatory protective mechanisms likely underlies the heritability of COPD observed in family studies. In alpha-1 protease inhibitor deficiency, the only genetic disorder known to cause COPD, lack of inhibition of elastase activity, results in the parenchymal destruction of emphysema. Other genetic polymorphisms have been hypothesized to alter the risk of COPD but have not been established as causes of this condition. It is likely that multiple genetic factors interacting with each other and with a number of environmental agents will be found to result in the development of COPD.

Major genetic effects on airway-parenchymal dysanapsis of the lung: the Humboldt family study

We examined familial resemblance and performed segregation analysis for the maximal expiratory flow rate at 50% of vital capacity (Vmax50) and the ratio of Vmax50 to forced vital capacity (FVC), based on data from 309 nuclear families with 1,045 individuals in the town of Humboldt, Saskatchewan, in 1993. Vmax50 is considered as an index of airway function and Vmax50/FVC is considered as an index of airway-parenchymal dysanapsis. Both Vmax50 and Vmax50/FVC were preadjusted for host characteristics (age, height, and weight), environmental factors, and history of respiratory symptoms and diseases in four separate groups (mothers, fathers, daughters, and sons). Both Vmax50 and Vmax50/FVC showed low father-mother correlations and significant parent-offspring and sibling-sibling correlations. Segregation analysis indicated that for residual Vmax50, the model of no-parent-offspring transmission with possible heterogeneity between two generations fitted the data as well as did the general model with arbitrary transmission probabilities. The Mendelian hypothesis for Vmax50 was rejected, which was consistent with our previous findings for other indexes of airway function. For residual Vmax50/FVC, however, a single locus explained all the familial resemblance and both no-parent-offspring-transmission hypotheses [tau(AA) = tau(AB) = tau(BB) = qA and tau(AA) = tau(AB) = tau(BB)] were rejected. The study provides evidence for a single locus influencing airway-parenchymal dysanapsis.

A genetic study of the depressive respiratory responses to hypoxia in chronic obstructive pulmonary disease patients with type II respiratory failure

OBJECTIVE

The depression of the ventilatory and P(0.1 )responses to hypoxia and hypercapnia may play an important role in the development of CO(2) retention in the patients with chronic obstructive pulmonary disease (COPD). The purpose of this study was to investigate if there is any linkage relationship between the depressed ventilatory and P(0.1) response phenotypes and the microsatellite markers on chromosome 6q21.1-21.2 among Chinese people.

METHODS

P(0.1) and ventilatory responses to hypoxia were measured in six COPD patients with type II respiratory failure, as well as in their 21 normal adult offsprings. Polymerase chain reaction (PCR), denaturing polyacrylamide gel electrophoresis and silver staining techniques were used to study the amplified fragment length polymorphism. Linkage analysis was done with the LINKAGE program.

RESULTS

Hypoxia response was low in 10 offsprings, and normal in the other 11 offsprings. Linkage analysis showed the maximum Lod score was 1.74(D6S276, theta = 0.10).

CONCLUSION

The depressed hypoxia response might have been influenced by genetic factors. The model was in accord with autosomal dominant inheritance. The disease-related gene was linked to D6S276 locus.

Association between alpha-1-antichymotrypsin polymorphism and susceptibility to chronic obstructive pulmonary disease

BACKGROUND

The antiproteases, including alpha-1-antitrypsin, are supposed to prevent lungs from becoming emphysematous. Genetic susceptibility to smoking injury may confer a risk for the development of chronic obstructive pulmonary disease (COPD).

METHODS

We have investigated the association between the polymorphism of alpha-1-antichymotrypsin (AACT), one of the antiproteases, and susceptibility to the development of COPD among heavy smokers. Blood samples obtained from both patients with COPD (n = 53) and control subjects (n = 65) at the Tokyo University Hospital, the Juntendo University Hospital and the Tokyo Kenbikyoin Clinic were used for this genotyping assay. Polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) were performed to genotype the AACT biallelic polymorphism in the signal peptide (-15 alanine to threonine), and the two polymorphisms of the exon (Pro229Ala and Leu55Pro).

RESULTS

The proportion of AACT/Ala-15 homozygotes was significantly higher in the COPD patients than in the control subjects (COPD 37.7% vs. control 18.5%). The odds ratio for AACT/Ala-15 homozygotes vs. all other genotypes was 2.7 (95% CI 1.2-6.2) for the COPD group. We could not find any association between the other two polymorphisms and COPD.

CONCLUSIONS

Genetic polymorphism in the signal peptide of AACT may be associated with individual susceptibility to the development of COPD, because the AACT/Ala-15 genotype is predominantly found in patients with COPD. It is suggested that AACT/Ala-15 genotype may be less protective against smoking injury.

Simple method for alpha1-antitrypsin deficiency screening by use of dried blood spot specimens

The use of dried blood spot (DBS) specimens in quantitative alpha1-antitrypsin (alpha1-AT) detection or genetic analysis is limited because protein levels in the samples are low and they contain components that can interfere with polymerase chain reaction amplification. A methodological adaptation was developed to overcome these drawbacks which is discussed here. The study population consisted of 200 healthy volunteers and 300 patients with chronic obstructive pulmonary disease (COPD). DBS specimens were tested for alpha1-AT concentration using a modified nephelometric assay and phenotyped with an isoelectric focusing method. Genetic diagnosis was established by deoxyribonucleic acid sequencing using a simple purification procedure to remove contaminants. The nephelometric method showed a detection limit of 0.284 mg x dL(-1), corresponding to a serum concentration of 13 mg x dL(-1). The correlation coefficient between alpha1-AT concentrations in DBS versus serum samples was R2=0.8674 (p<0.0001). All 200 healthy individuals had DBS alpha1-AT concentrations >1.9 mg x dL(-1), corresponding to 114 mg x dL(-1) in serum samples. One hundred and twenty-five COPD patients (42%) showed alpha1-AT values <1.8 mg x dL(-1). Twenty patients with the PIZ phenotype had alpha1-AT values lower than 0.64 mg x dL(-1). On the basis of genotyping, one COPD patient was classified as heterozygous (PIMM(heerlen)). Selective elution of contaminants resulted in optimal alpha(1)1-antitrypsin genotyping. Because of its sensitivity and excellent correlation with the standard method, the dried blood spot quantitative assay is a reliable tool for routine measurement of alpha1-antitrypsin.