Tumor necrosis factor gene complex in COPD and disseminated bronchiectasis

BACKGROUND

Tumor necrosis factor (TNF) is a potent proinflammatory cytokine with increased levels in the sputum of COPD subjects. Two biallelic TNF gene complex polymorphisms have been described: LtalphaNcoI, in the first intron of the lymphotoxin alpha (previously referred to as TNF-beta) gene, and TNF-308, in the promoter region of the TNF-alpha gene. Higher levels of TNF production are associated with allele 1 of LtalphaNcoI (LtalphaNcoI*1) and with allele 2 of TNF-308 (TNF-308*2).

STUDY OBJECTIVES

To study the frequencies of the two TNF gene complex polymorphisms in patients with COPD and bronchiectasis.

DESIGN

Association study.

SUBJECTS AND METHODS

We studied the frequencies of these polymorphisms in 66 subjects with COPD and in 23 subjects with disseminated bronchiectasis and compared them to the frequencies in 98 healthy control subjects and 45 subjects with nonobstructive pulmonary disease. Genomic DNA samples were extracted, and TNF-alpha and LtalphaNcoI polymorphisms were detected after polymerase chain reaction by restriction digestion.

RESULTS

We found the following frequencies: the TNF-308*2 allele was detected in 11% of COPD individuals, 15% of bronchiectasis patients, 10% of healthy control subjects, and 18% of subjects with nonobstructive pulmonary disease. The LtalphaNcoI*1 allele was detected in 28% of COPD individuals, 30% of bronchiectasis patients, 29% of healthy control subjects, and 29% of subjects with nonobstructive pulmonary disease. We found evidence of linkage disequilibrium between the two loci (Delta = 0.068).

CONCLUSIONS

We conclude that the TNF gene complex, at least in Caucasoid individuals and for the considered polymorphisms, does not seem to play a major role as genetic risk factor in COPD and bronchiectasis.

Parental factors affecting respiratory function during the first year of life

In a prospective, longitudinal, population-based cohort study of familial and environmental influences on the development of wheezing respiratory illness in early childhood, we identified infant length, weight, gender, and exposure to maternal cigarette smoking as significant determinants of lung function during the first year of life. A cohort of 237 infants (106 females: 131 males) was evaluated, and 496 lung function measurements were made between the ages of 1-12 months. Respiratory function was assessed using the rapid thoracic compression technique to obtain maximum expiratory flow at functional residual capacity (V'maxFRC). Parental history of asthma and smoking habits during pregnancy were obtained by questionnaire. Data were analyzed using a longitudinal random effects model. Infants with a parental history of asthma and/or in utero passive smoke exposure were compared to a reference group of infants who had no parental history of asthma and in whom neither parent smoked pre- or postnatally. Boys were found to have a consistently lower V'maxFRC (-21.05 mL.s(-1)) throughout the first year of life in comparison to girls (P < 0.05). Maternal smoking during pregnancy was associated with a lower V'maxFRC in both genders in comparison to unexposed infants (P < 0.05). V'maxFRC was unaffected by parental history of asthma. Gender-specific normative equations for V'maxFRC throughout the first year of life were derived for the infant cohort as a whole and also for subgroups of infants, based on parental asthma and smoking history. We conclude that lung function during the first year of life differs between genders and is adversely affected by in utero passive tobacco smoke exposure. Gender-specific predictive equations for V'maxFRC should be used during infancy.

Analysis of Moraxella catarrhalis by DNA typing: evidence for a distinct subpopulation associated with virulence traits

Two DNA typing methods, probe-generated restriction fragment length polymorphism analysis and single-adapter amplified fragment length polymorphism analysis, were used to study the genetic relationships among 90 Moraxella catarrhalis strains. Both methods were found to be highly concordant, generating a dendrogram with 2 main branches. The division of the M. catarrhalis population into 2 subspecies was supported by analysis of the 16S rRNA sequences. Both beta-lactamase-positive and beta-lactamase-negative strains were found in all main branches, suggesting horizontal transfer of the beta-lactamase gene. In contrast, 2 virulence traits, complement resistance and adherence to epithelial cells, were strongly associated with 1 of the 2 subspecies. The branch depth suggested that complement-resistant adherent strains diverged from a common ancestor more recently than did complement-sensitive nonadherent strains. These findings suggest the existence of subpopulations of M. catarrhalis that differ in virulence, and they may have implications for vaccine development.

Developmental myosin heavy chains in the adult human diaphragm: coexpression patterns and effect of COPD

In preliminary experiments we noted developmental (i.e., embryonic and neonatal) myosin heavy chains (MHCs) in the diaphragms of patients with severe chronic obstructive pulmonary disease (COPD). We hypothesized that this finding represented new fiber formation secondary to injury associated with the mechanical stress of COPD or previously undescribed MHCs in the human diaphragm. To distinguish between these possibilities, we analyzed diaphragmatic biopsies obtained from 9 patients with severe COPD (forced expiratory volume in 1 s = 21 +/- 2% predicted, residual volume = 283 +/- 22% predicted) and 10 age-matched controls. First, using immunocytochemistry with specific monoclonal antibodies, we noted that control diaphragms had greater proportions of fibers expressing embryonic (50 +/- 2 vs. 28 +/- 3%, P < 0.0001) and neonatal (52 +/- 2 vs. 32 +/- 3%, P < 0.001) MHCs than COPD diaphragms. Second, SDS-PAGE demonstrated that these developmental MHCs represented only a very small fraction of the diaphragmatic MHC content. Third, the RT-PCR demonstrated mRNA coding for embryonic and neonatal MHCs in COPD and control diaphragms. Last, COPD and control diaphragms exhibited normal histology on light microscopy. We conclude that the presence of developmental MHC isoforms does not indicate new fiber formation in diaphragms of patients with severe COPD. Although these results represent the first systematic description of embryonic and neonatal MHCs in normal adult human diaphragms, their function remains to be elucidated.

Localization of gamma-glutamylcysteine synthetase messenger rna expression in lungs of smokers and patients with chronic obstructive pulmonary disease

Cigarette smoking results in an oxidant/antioxidant imbalance in the lungs and inflammation, which are considered to be key factors in the pathogenesis of chronic obstructive pulmonary disease (COPD). Glutathione (GSH) is an important protective antioxidant in lung epithelial cells and epithelial lining fluid. De novo GSH synthesis in cells occurs by a two-enzyme process. The rate-limiting enzyme is gamma-glutamylcysteine synthetase (gamma-GCS), in which the heavy subunit (HS) constitutes most of its catalytic activity. The localization and expression of gamma-GCS-HS in specific lung cells as well as possible differences in its expression between smokers with and without COPD have not yet been studied. The purpose of this study was to investigate gamma-GCS-HS expression using messenger RNA in situ hybridization in peripheral lung tissue. We studied 23 current or ex-smokers with similar smoking histories with (n = 11; forced expiratory volume in 1 s [FEV(1)] < 75% predicted) or without COPD (n = 12; FEV(1) < 84% predicted). We assessed the relations between pulmonary gamma-GCS-HS expression, FEV(1) and transforming growth factor-beta1 (TGFbeta(1)), because TGFbeta(1) can modulate gamma-GCS-HS expression in lung epithelial cells. Gamma-GCS-HS is predominantly expressed by airway and alveolar epithelial cells, alveolar CD68+ cells (macrophages), and endothelial cells of both arteries and veins. In subjects with COPD, semiquantitative analysis revealed higher levels of gamma-GCS-HS messenger RNA in alveolar epithelium (1.5 times, p <.04) and a trend for a higher expression in bronchiolar epithelium (1.3 times, p =.075) compared with subjects without COPD. We did not observe a significant correlation between airway and alveolar epithelial gamma-GCS-HS expression and TGFbeta(1) expression (r =.20), FEV(1) percentage predicted (r =.18), or FEV(1)/forced vital capacity ratio (r =.14; p.05). Our results show that gamma-GCS-HS is localized, particularly in lung epithelium, and shows higher expression in smokers with COPD. This suggests a specific role for enhanced GSH synthesis as a mechanism to provide an adaptive response against oxidative stress in patients with COPD.

Feasibility of a clinical trial of augmentation therapy for alpha(1)-antitrypsin deficiency. The Alpha 1-Antitrypsin Deficiency Registry Study Group

We examined the feasibility of a randomized clinical trial of intravenous augmentation therapy for individuals with alpha 1-antitrypsin (alpha1AT) deficiency, basing calculations on newly available data obtained from the NHLBI Registry of Patients with Severe Deficiency of Alpha 1-Antitrypsin. Using rate of FEV(1) decline as the primary outcome and adjusting for noncompliance, a study of subjects with Stage II chronic obstructive pulmonary disease (COPD) (initial FEV(1) 35 to 49% predicted) with biannual spirometry measures obtained over 4 yr of follow-up would require 147 subjects per treatment arm to detect a difference in FEV(1) decline of 23 ml/yr (i.e., a 28% reduction), the difference observed in the NHLBI Registry (1-sided test, alpha = 0.05, 90% power). To detect a 40% reduction in mortality in a 5-year study of subjects with baseline FEV(1) 35 to 49% predicted, recruited over the first 2 yr and then followed an additional 3 yr, 342 subjects per treatment arm would be needed. Though significant impediments to carrying out a clinical trial exist, including the cost of such a trial and the potential difficulties in recruiting patients for a placebo-controlled trial, we recommend a randomized controlled trial as the best method to evaluate the efficacy of intravenous augmentation therapy and of possible future treatments.

Genetic susceptibility to chronic obstructive pulmonary disease in Koreans: combined analysis of polymorphic genotypes for microsomal epoxide hydrolase and glutathione S-transferase M1 and T1

BACKGROUND

Although smoking is the major causal factor in the development of chronic obstructive pulmonary disease (COPD), only 10-20% of chronic heavy cigarette smokers develop symptomatic COPD which suggests the presence of genetic susceptibility. This genetic susceptibility to COPD might depend on variations in enzyme activities that detoxify cigarette smoke products such as microsomal epoxide hydrolase (mEPHX) and glutathione-S transferase (GST). As there is increasing evidence that several genes influence the development of COPD, multiple gene polymorphisms should be investigated to find out the genetic susceptibility to COPD.

METHODS

The genotypes of 83 patients with COPD and 76 healthy smoking control subjects were determined by polymerase chain reaction (PCR) followed by restriction fragment length polymorphism (PCR-RFLP) for the mEPHX gene, and multiplex PCR for GST M1 and GST T1 genes. The frequencies of polymorphic genotypes of mEPHX, GST M1, and GST T1 genes were compared both individually and in combination in patients with COPD and healthy smokers.

RESULTS

No differences were observed in the frequency of polymorphic genotypes in exons 3 and 4 of mEPHX, GST M1, and GST T1 genes between patients with COPD and healthy smokers. The frequencies of any combination of these genotypes also showed no differences between the COPD group and the control group.

CONCLUSIONS

Genetic polymorphisms in mEPHX, GST M1, and GST T1 genes are not associated with the development of COPD in Koreans.

Tumour necrosis factor-alpha gene promoter polymorphism in chronic obstructive pulmonary disease

Tumour necrosis factor(TNF)-alpha levels are elevated in airways of patients with chronic obstructive pulmonary disease (COPD) and may contribute to its pathogenesis. A guanine to adenine substitution at position -308 of the TNF-alpha gene promoter (TNF1/2) has been associated with chronic bronchitis of various aetiologies in a Taiwanese population. The authors performed a study investigating association of the polymorphism with smoking-related COPD in Caucasians. Frequencies of TNF1/2 alleles in 86 Caucasians (52 males) with COPD were compared with 63 (52 males) asymptomatic smoker/exsmoker control subjects and a population control of 199 (99 males) blood donors. Genotyping was performed by the polymerase chain reaction-restriction fragment length polymorphism technique on genomic deoxyribonucleic acid (DNA) obtained from peripheral blood. There were no significant differences in TNF1/2 allele frequencies between groups: 0.85/0.15 in COPD, 0.85/0.15 in smoker control subjects, 0.83/0.17 in population control subjects. Within the COPD group there was no association of TNF1/2 alleles with indices of airflow obstruction (% predicted forced expiratory volume in one second (FEV1) and % predicted FEV1/vital capacity ratio) nor gas transfer (% predicted carbon monoxide transfer coefficient and % predicted carbon monoxide diffusing capacity of the lung). It is concluded that: 1) the tumour necrosis factor gene promoter allele does not influence the risk of developing chronic obstructive pulmonary disease in a Caucasian population of smokers; and 2) there is no association of the tumour necrosis factor gene promoter genotype with severity of airflow obstruction nor degree of emphysema in chronic obstructive pulmonary disease.

Inactive conformation of the serpin alpha(1)-antichymotrypsin indicates two-stage insertion of the reactive loop: implications for inhibitory function and conformational disease

The serpins are a family of proteinase inhibitors that play a central role in the control of proteolytic cascades. Their inhibitory mechanism depends on the intramolecular insertion of the reactive loop into beta-sheet A after cleavage by the target proteinase. Point mutations within the protein can allow aberrant conformational transitions characterized by beta-strand exchange between the reactive loop of one molecule and beta-sheet A of another. These loop-sheet polymers result in diseases as varied as cirrhosis, emphysema, angio-oedema, and thrombosis, and we recently have shown that they underlie an early-onset dementia. We report here the biochemical characteristics and crystal structure of a naturally occurring variant (Leu-55-Pro) of the plasma serpin alpha(1)-antichymotrypsin trapped as an inactive intermediate. The structure demonstrates a serpin configuration with partial insertion of the reactive loop into beta-sheet A. The lower part of the sheet is filled by the last turn of F-helix and the loop that links it to s3A. This conformation matches that of proposed intermediates on the pathway to complex and polymer formation in the serpins. In particular, this intermediate, along with the latent and polymerized conformations, explains the loss of activity of plasma alpha(1)-antichymotrypsin associated with chronic obstructive pulmonary disease in patients with the Leu-55-Pro mutation.

Microsomal epoxide hydrolase genotypes and chronic obstructive pulmonary disease in Japanese

Polymorphisms in the gene for microsomal epoxide hydrolase (mEPHX), an enzyme involved in the protective mechanism against oxidative stress, have been reported to be associated with individual susceptibility to the development of chronic obstructive pulmonary disease (COPD). The polymorphisms in exons 3 and 4 in the mEPHX gene were examined in a total of 358 Japanese individuals, including 40 patients with COPD and 71 patients with lung cancer. The overall frequencies of variant allele for mEPHX codons 113 (exon 3) and 139 (exon 4) were 44% and 14%, respectively. Moreover, a novel single nucleotide polymorphism (estimated allele frequency: 0.29) was identified in Japanese at 20 bp downstream of the codon 113 polymorphism with strong linkage disequilibrium with the wild allele for codon 113. While the frequencies of variant allele and proportions of individuals homozygous variant for codon 113, assumed having very slow mEPHX activity, were similar among COPD or lung cancer patients and the control population, they were significantly higher in patients with severe COPD than in those with mild COPD [P=0.0225, odds ratio 2.9 (95%CI 1.1-7.4); P=0.0350, respectively]. Thus, we found that the frequency of the variant allele for mEPHX codon 113 is higher in Japanese than that in Caucasians (P=0.0028), a novel silent polymorphism exists in exon 3 and shows strong linkage disequilibrium with the wild allele for codon 113, and individual homozygous variants for codon 113 may be associated with development of advanced COPD rather than the susceptibility to COPD.

Risk of hospital admission for obstructive pulmonary disease in alpha(1)-antitrypsin heterozygotes of phenotype PiMZ

Whether subjects heterozygous for alpha(1)-antitrypsin (alpha(1)-AT) deficiency are at risk for development of obstructive pulmonary disease (OPD) has been discussed for the past three decades. Both cohort and case-control studies have reached different conclusions, with the major problems being small sample sizes. A cohort of heterozygotes with the phenotype PiMZ was retrieved from the Danish Alpha(1)-Antitrypsin Deficiency Registry. Ten matched controls for each PiMZ subject were identified from the files of the Danish Central Population Registry. Cases and controls were subsequently linked to the files of the Danish Hospital Discharge Registry, and relative risk for OPD was calculated. In the cohort of 1,551 PiMZ subjects (11,678 person-years), we identified 47 subjects with a discharge diagnosis of OPD, as compared with 206 subjects with this diagnosis in the control group (109,748 person-years), yielding a relative risk (RR) of 2.2 (95% confidence interval [CI]: 1.5 to 3.0). This increased risk was present in both men and women and in all age groups; however, it was significant only in the age group from 40 to 79 yr. Of the 1,551 PiMZ subjects, 565 (36%) were first-degree relatives of PiZ index cases, and it appeared that only this group was at increased risk of hospital admission for OPD (RR: 3.4, 95% CI: 2.2 to 5.3). We conclude that alpha(1)-AT heterozygotes of phenotype PiMZ are at increased risk of hospital admission for OPD if they are first-degree relatives of PiZ index cases only, and that other, yet unknown genetic or environmental factors contribute to the development of lung disease.

Cytogenetic damage and ras p21 oncoprotein levels from patients with chronic obstructive pulmonary disease (COPD), untreated lung cancer and healthy controls

The purpose of the present communication was to determine in patients with chronic obstructive pulmonary disease (COPD), untreated lung cancer and healthy controls if there was a possible association between the disease state and biomarkers of cytogenetic damage and ras p21 oncoprotein levels, and if various exogenous confounding factors such as smoking habit and endogenous ones (sex, cancer in the immediate family) could affect these biomarkers. The individuals in all groups were as well-matched as possible for age to determine if this could be eliminated as a confounder. Peripheral blood and plasma were collected from 20 COPD patients, 31 cancer patients and 20 healthy controls. Chromosomal aberrations (CA), sister chromatid exchanges (SCE) and high frequency SCE cells (HFC) were examined from the blood and ras p21 oncoproteins from the plasma. These parameters were used as biomarkers of genotoxic anomalies. All the biomarkers were examined for their relationship to the confounding factors. Results were analysed by a t-test, analysis of variance (ANOVA) and stepwise multivariate regression analysis. There was an increase in CA, although not statistically so, in COPD and cancer patients by comparison with healthy controls, but there was a statistically significant increase in SCE, HFC and ras p21 oncoproteins. There was also a statistically significant difference between respiratory volume parameters in COPD patients and controls. Respiratory parameters were not measured in cancer patients. Ras p21 oncoproteins were also statistically significantly increased in the COPD and cancer patients, suggesting that the disease state alone might be sufficient to increase the oncoproteins, or that some of the COPD patients were in the process of developing cancer or perhaps some would die from COPD before cancer developed. Smoking was shown to have a marked effect on all parameters investigated. Ex-smokers showed less effects. Since age was very well controlled, there was little effect due to age. There was an effect due to sex, but cancer in the immediate family had little effect on any of the parameters.

Bronchodilator responsiveness and serum total IgE levels in families of probands with severe early-onset COPD

Bronchodilator responsiveness has been associated with a subsequent accelerated decline in forced expiratory volume in one second (FEV1). Therefore, bronchodilator responsiveness and total serum immunoglobulin E(IgE) levels were assessed in 184 adult first-degree relatives of probands with severe early-onset chronic obstructive pulmonary disease (COPD) and a control group. Greater bronchodilator responsiveness was found among current smokers or exsmokers who were first-degree relatives of early-onset COPD probands than in currently or exsmoking controls, expressed as increase in FEV1 as a percentage of baseline (5.8+/-8.1 versus 2.9+/-5.1%, p<0.01), absolute increase in FEV1 from baseline (120+/-130 versus 60+/-110 mL, p<0.05), and increase in FEV1 as a percentage of the predicted value (3.6:4.1 versus 2.2+/-3.9%, p<0.05). However, elevated total serum IgE levels were not found in first-degree relatives of early-onset COPD probands compared with control subjects. The increased bronchodilator responsiveness among currently smoking/exsmoking first-degree relatives of early-onset COPD probands suggests that these individuals may have enhanced susceptibility to the detrimental effects of cigarette smoking.

Control of mucin transcription by diverse injury-induced signaling pathways

Mucin production is an evolutionarily ancient defense mechanism that is retained in mammals and operates at all mucosal surfaces to protect the host against pathogens and irritants. As in lower organisms, the mammalian mucosa (epithelium) produces mucin in response to diverse insults. Our studies aim to understand the intracellular signaling and gene regulation mechanisms mediating mucin production in response to clinically important insults. To date, we find that the signaling pathway triggered by each type of insult is distinct. Relatively common, however, is the involvement of the protein tyrosine kinase c-Src, the MAP kinase kinase MEK 1/2, and the transcription factor NF-kappaB. Basbaum C, Lemjabbar H, Longphre M, Li D, Gensch E, McNamara N. Control of mucin transcription by diverse injury-induced signaling pathways.

Peripheral blood lymphocyte subpopulations in schoolchildren born very preterm

AIM

To investigate whether lymphocytes or serum inflammatory markers are associated with obstructive lung disease and bronchial lability in schoolchildren born very preterm.

METHOD

Lymphocyte subsets were studied in the peripheral venous blood of 29 such children (median age 8.8 years). Serum eosinophil cationic protein (ECP) and myeloperoxidase (MPO) concentrations and the association between them, lymphocyte subsets, and lung function were studied. Fourteen healthy children born at term, median age 9.1 years, served as controls. T lymphocytes (CD3), T lymphocyte subpopulations (CD4 and CD8), B lymphocytes (CD19), natural killer cells (CD16+56) and activation markers of T and B lymphocytes (CD23 and CD25) were determined using flow cytometry. Lung function was measured in all children both in the clinic and at home (Vitalograph Data Storage Spirometer).

RESULTS

Compared with the controls, schoolchildren born very preterm had significantly lower CD4(+) T cell percentages and CD4:CD8 ratios (p < 0.05 for both), whereas natural killer cell percentages and serum ECP values were significantly higher (p < 0. 05). The very preterm schoolchildren had significantly lower spirometric values than the control group (p < 0.05)-except forced vital capacity. When all the subjects were considered together, a weak, but significant, negative association was observed between the bronchial responsiveness in peak expiratory flow, after a beta(2) agonist during home monitoring, and the CD4(+) T cell percentage (r = -0.45; p = 0.008) and the CD4:CD8 ratio (r = -0.50; p = 0.003), indicating a relation between bronchial lability and imbalance of T cell subpopulations.

CONCLUSIONS

These results suggest that there is an inflammatory basis for lung function abnormalities in schoolchildren born very preterm.

Risk factors for early, persistent, and late-onset wheezing in young children. SIDRIA Collaborative Group

Wheezing in childhood is not a single disorder and different wheezing-associated respiratory illnesses have been recently described. We investigated the association between wheezing conditions and familial, pre-, peri-, and postnatal risk factors. We studied 16,333 children, 6 to 7 yr old, enrolled in a population-based study. Standardized questionnaires were filled in by parents. A total of 1,221 children had transient early wheezing, 671 had persistent wheezing, 918 had late-onset wheezing, and 13,523 never had wheezing or asthma (control group). Maternal asthma or chronic obstructive airway disease were significantly (p < 0.0001) more associated with persistent wheezing than with transient early and late-onset wheezing. The same pattern was observed for exposure to maternal smoke during pregnancy. Having a mother > 35 yr old was protective against transient early wheezing (odds ratio [OR]: 0.68, 95% confidence intervals [95% CI]: 0.53 to 0.86). Breast feeding >/= 6 mo was slightly protective against transient early wheezing (OR: 0.82, 95% CI: 0.68 to 0.97), whereas it was a moderate risk factor for late-onset wheezing (OR: 1.22, 95% CI: 0.99 to 1.50). On the contrary, having siblings and attending a day care center were both risk factors for transient early wheezing (OR: 1.41 [95% CI: 1.21 to 1.64] and 1.70 [95% CI: 1.48 to 1.96], respectively) and protective factors against wheezing of late onset (OR: 0.83 [95% CI: 0.70 to 0.97] and 0.72 [95% CI: 0.59 to 0.88]). There was a stronger (p < 0.0001) positive association between personal history of eczema or allergic rhinitis and persistent and late-onset wheezing than transient early wheezing. Our findings suggest a different contribution of risk factors to wheezing conditions in childhood.

[Genetic risk factors for chronic obstructive pulmonary disease (COPD)]

Cigarette smoking has been shown to be a major environmental risk factor predisposing to the development of chronic obstructive pulmonary disease (COPD). However, only 10-20% of cigarette smokers develop COPD, implying undue susceptibility compared with the remainder of the population at large. Studies of families and twins suggest that genetic factors also contribute to development of COPD. We review the genes which have been investigated as potential risk factors for COPD. The fully established genetic risk factor is only alpha 1-antitrypsin deficiency. Polymorphisms for the genes including alpha 1-antichymotrypsin, vitamin D-binding protein, microsomal epoxide hydrolase, cytochrome P450 1A1, Glutathione S-transferase and immunoglobulin A, have also been associated with the development of COPD. Other genetic factors are likely involved but have not yet been identified. Elucidation of additional genetic risk factors may provide useful insights into the pathogenesis of COPD. Potential interactions between the various environmental and genetic risk factors may be important determinants in development of COPD.

alpha 1-antitrypsin TAQ I polymorphism and alpha 1-antichymotrypsin mutations in patients with obstructive pulmonary disease

Obstructive pulmonary disease is a multifactorial condition deriving from the interaction of environmental and genetic factors. From biochemical knowledge of the basis of the disease, alpha 1-antitrypsin and alpha 1-antichymotrypsin are considered two likely candidate genes. We therefore designed an association study comprising 232 unrelated Italian individuals divided as follows: 89 individuals with obstructive lung disease (66 with COPD and 23 with disseminated bronchiectasis) and 143 controls (45 patients with non-obstructive lung disease and 98 healthy individuals). We screened for Taq I (G1237A) polymorphism of the alpha 1-antitrypsin gene as well as the rare variants Bonn-1 (Pro229Ala), Bochum-1 (Leu55Pro), Isehara-1 (Met389Val) and Isehara-2 (1258delAA), and the common signal peptide polymorphism Thr-15Ala of the alpha 1-antichymotrypsin gene. The frequencies of Taq I G1237A alleles were 11.7 and 10.8% in obstructed patients and controls, respectively (P = 0.43), while those of signal peptide Thr-15Ala alleles were 51.6 and 50.3% in obstructed patients and controls, respectively (P = 0.42). We conclude that alpha 1-antitrypsin Taq I polymorphism and alpha 1-antichymotrypsin Thr-15Ala mutation are not major genetic risk factors for the development of obstructive lung disease in Italian patients. The alpha 1-antichymotrypsin rare variants were not detected: our results do not exclude the possibility that other alpha 1-antichymotrypsin gene mutations might be present in Italian obstructed patients but, if so, these genetic defects must be rare.

Glutathione S-transferase P1 (GSTP1) polymorphism in patients with chronic obstructive pulmonary disease

BACKGROUND

Enzymes that contribute to the local detoxification in alveoli and bronchioles have an important role in the defence mechanism against tobacco smoke. It has been suggested that genetic susceptibility to smoking injury may confer a risk for the development of chronic obstructive pulmonary disease (COPD). The polymorphisms in glutathione S-transferase P1 (GSTP1), a xenobiotic metabolising enzyme, were investigated in patients with COPD.

METHODS

Polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) were performed to genotype GSTP1 polymorphisms in exon 5 (Ile105Val) and exon 6 (Ala114Val). Blood samples were taken from 53 patients with COPD and 50 control subjects at the Tokyo University Hospital, the Juntendo University Hospital, and the Tokyo Kenbikyoin Clinic for use in the study.

RESULTS

The proportion of GSTP1/Ile105 homozygotes was significantly higher in the patients with COPD than in the control subjects (79% vs 52%). The odds ratio for GSTP1/Ile105 homozygotes versus all other genotypes was 3.5 (95% CI 2.7 to 4.6) for COPD. Polymorphism at residue 114 of GSTP1 was not found in either group.

CONCLUSIONS

Genetic polymorphism of exon 5 of GSTP1 may be associated with COPD because the GSTP1/Ile105 genotype is predominantly found in COPD. It is suggested that the GSTP1/Ile105 genotype may be less protective against xenobiotics in tobacco smoke.

[Alpha 1-protease inhibitor deficiency. Diagnosis, follow-up and therapy options]

DEFINITION

Alpha-1 antitrypsin (alpha-1 proteinase inhibitor) deficiency is characterized by a marked reduction of alpha-1 antitrypsin, the major antiprotease in man.

PREVALENCE

Alpha-1 antitrypsin deficiency is one of the most common hereditary diseases in Caucasians of European descent. Alpha-1 antitrypsin deficiency is the underlying disorder in approximately 2% of all patients with chronic obstructive pulmonary disease and lung emphysema.

CLINICAL MANIFESTATIONS

Young adults by the age of 30 to 45 years have a high risk for the development of lung emphysema with cough, sputum expectoration and respiratory insufficiency. There is a moderate risk of liver disease.

DIAGNOSTIC PROCEDURES AND TREATMENT

The diagnosis is obtained by measurement of alpha-1 antitrypsin serum levels. Recognition of the disorder is important to prevent deterioration of the pulmonary function by early initiation of preventive measures and treatment. Therapeutic options are physiotherapy, antiobstructive medication and antibiotics. The most direct approach is the intravenous augmentation therapy with purified alpha-1 antitrypsin.

Microsatellite DNA instability in COPD

STUDY OBJECTIVES

Cigarette smoking is the prime cause of COPD; however, only a few smokers develop the disease. In a previous study, we demonstrated that microsatellite DNA instability (MSI) is a detectable phenomenon in sputum cells of COPD patients. Therefore, we hypothesize that this genetic alteration may indicate susceptibility to COPD.

DESIGN

In order to investigate this hypothesis, we compared smokers who developed COPD with smokers who did not develop COPD (referred to as non-COPD smokers).

SETTING

Seven highly polymorphic microsatellite markers were targeted on the DNA of sputum cells and of WBCs.

PATIENTS AND PARTICIPANTS

We studied 60 non-COPD smokers and 59 severe COPD patients with a similar smoking history (mean +/- SD) of 48+/-25 and 54+/-33 pack-years, respectively (p = 0.77). Non-COPD smokers were tested once; COPD smokers were tested twice, with an interval of 24 months between tests.

RESULTS

MSI was detected in 14 COPD patients (24%) but in none of the non-COPD smokers. In 10 COPD patients, MSI was exhibited by one microsatellite marker; in the remaining 4 COPD patients, MSI was exhibited by two different alleles. The most commonly affected marker was THRA1 on chromosome 17 (43%). No significant differences were found between MSI-positive and MSI-negative COPD patients for clinical or laboratory parameters, survival, and development of lung cancer. No change in the microsatellite alleles was found between the tests performed with a 24-month interval.

CONCLUSIONS

This study demonstrated that MSI was found exclusively in the sputum cells of smokers with COPD. The results support the hypothesis that MSI could be part of the complex genetic basis of COPD, and it could be a marker of the genetic alteration caused by smoking that allows COPD to develop.