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Helicobacter pylori and chronic bronchitis.

BACKGROUND: Chronic infections such as those caused by Helicobacter pylori, Chlamydia pneumoniae, and cytomegalovirus have been epidemiologically related to coronary heart disease (CHD). Other studies place H. pylori in relation to other extradigestive diseases. We carried out an epidemiologic pilot study to evaluate the prevalence of H. pylori in patients with chronic bronchitis, a respiratory disease characterized by persistent chronic inflammation, in comparison with a matched control group. METHODS: An enzyme-linked immunosorbent assay IgG test for H. pylori diagnosis was performed in 60 consecutive patients with chronic bronchitis (15 women and 45 men; age range, 50-89 years; mean age, 70.38 years) and in 69 control subjects, well matched for age and social status (19 women and 50 men: age range, 52-90 years; mean age, 71.3 years). RESULTS: Foty-nine of 60 patients with chronic bronchitis (81.6%) and 40 of 69 subjects in the control group (57.9%) were H. pylori-positive (P = 0.0079). The odds ratio, calculated by simple analysis (3.2) and confirmed by logistic regression analysis (3.399), indicated that H. pylori infection greatly increases the risk of chronic bronchitis. CONCLUSIONS: To date, CHD is the only convincing association between H. pylori infection and an extradigestive disease. The main conclusion of this pilot study is that H. pylori infection seems to increase the risk of developing of chronic bronchitis. An important step in this field will be to evaluate the possible change in the clinical conditions after successful eradication therapy in H. pylori-positive patients with chronic bronchitis.

Aged↗

Animal models of chronic bronchitis and their relevance to studies of particle-induced disease.

Chronic bronchitis is a significant cause of morbidity and mortality. Chronic irritation of the conducting airways by inhaled substances, most importantly cigarette smoke, air pollution, and occupational exposures, is thought to be a key factor in the pathogenesis of chronic bronchitis. Microbial infections have been implicated in acute exacerbations of bronchitis and in its progression. Several animal models of chronic bronchitis have been developed. This review examines similarities and dissimilarities among commonly used animal models of bronchitis and the human disease. The most commonly used animal models of chronic bronchitis are those employing SO2, tobacco smoke, lipopolysaccharide (endotoxin), proteases, and secretagogues. Bronchiolitis induced by nickel and nitric acid have also been reported. Rats, hamsters, and dogs are the species most frequently used; sheep and monkeys have been used less frequently. These models vary in the extent or location of mucous-cell hyperplasia and metaplasia, airway inflammation, chronicity, ease of induction, and reproducibility. Frequently, the deficiencies in these models are attributable to anatomic differences between human and animal airways, differences in the severity or chronicity of inflammation or fibrosis, or lack of complete characterization of the responses and their time course in the animal model. These animal models may be useful for investigating how, and under what exposure conditions, ambient pollutants might exacerbate airway inflammation, mucus hypersecretion, and airflow limitation.

Air Pollutants↗

Chronic bronchitis in an elderly population.

BACKGROUND: in order to describe the prevalence and prognostic implications of chronic bronchitis in individuals 65 years or older we analysed data from The Copenhagen City Heart Study. METHODS: the population was studied in 1976-1978 resurveyed in 1981-1983 and 1991-1994 and followed with regard to survival for up to 12 years. Approximately 3,700 elderly participants with a mean age of 76 years were available for analyses. RESULTS: the prevalence of chronic bronchitis was 13.0% in women and 18.6% in men. Multiple logistic regression yielded the following predictors for chronic bronchitis: male gender (odds ratio with 95% confidence interval = 1.1 (0.9-1.3)), previous smoking odds ratio = 1.7 (1.2-2.2), present smoking odds ratio = 2.1 (2.1-3.8), previous exposure to dusts and fumes (odds ratio = 2.2 (1.7-2.7)), chest infections in childhood (odds ratio = 2.1 (1.6-2.9)), more than 6 chest infections in previous 10 years (odds ratio = 6.2 (4.1-9.2)) and alcohol consumption of more than 3 drinks a day (odds ratio = 1.8 (1.3-2.3)). Chronic bronchitis was a significant predictor of both subsequent respiratory infections and survival. After adjustment for age, smoking and lung function, a Cox regression showed that chronic bronchitis was significantly related to mortality from all causes with a hazard ratio with 95% confidence interval = 1.3 (1.1-1.4), all benign respiratory diseases (hazard ratio = 2.0 (1.6-2.7)), obstructive lung disease (hazard ratio = 2.5 (1.7-3.6)) and lung cancer (hazard ratio = 2.0 (1.4-2.9)). CONCLUSIONS: in an elderly population, chronic bronchitis is a prevalent condition with important prognostic implications.

Aged↗

A study of clinical features and treatment of acute bronchitis by Japanese primary care physicians.

OBJECTIVE: This study aimed to examine the factors affecting prescription of antibiotics for acute bronchitis in ambulatory care settings in Japan. METHOD: A prospective study was conducted on 92 physicians engaged in primary care regarding their prescription behaviour for a series of 20 new patients with acute respiratory diseases seen during November 1996 and the background factors affecting the behaviour. RESULTS: A total of 1755 patients were registered during the study period, 302 (17.2%) of whom were diagnosed with acute bronchitis and 1165 (66.4%) with upper respiratory tract infection. Independent background factors related to diagnosis of acute bronchitis included self-care prior to visit (odds ratio 1.93, 95% CI 1.33-2.80), complaints such as cough (8.80, 4.77-16.2), sputum (2.24, 1.59-3.14) and purulent sputum (6.47, 3.02-13.9). The odds ratio was high in patients with more severe findings of the chest (5.00, 3.64-6.85), given chest X-ray (2.68, 1.33-5.38) while it was low in those feeling cold (0.68, 0.48-0.96), and those with a sore throat (0.63, 0.45-0.90), nasal symptoms (0.75, 0.54-1.04) and more severe findings of the pharynx (0.74, 0.58-0.92). In those with an upper respiratory tract infection, the odds ratio was high for complaints such as feeling cold (1.51, 1.11-2.05) and nasal symptoms (1.39, 1.04-1.86), while it was low for complaints such as cough (0.67, 0.48-0.95), sputum (0.43, 0.30-0.62), purulent sputum (0.19, 0.08-0.44), wheeze (0.34, 0.13-0.92), in those with more severe findings of the tonsil (0.36, 0.29-0.44) and the chest (0.30, 0.19-0.47) and given chest X-rays (0.29, 0.12-0.66). For acute bronchitis, antibiotics were administered to 67.5% and symptomatic therapy concurrently given to 64.9%. As for independent background factors related to prescription of antibiotics for acute bronchitis, the odds ratio was higher in physicians denying the efficacy of antibiotics for treating a cold (4.58, 1.94-10.8), and the patients with complaints such as purulent sputum (22.9, 2.66-197.2), more severe findings of the pharynx (2.26, 1.34-3.79) and of the chest (2.73, 1.53-4.88), and those who had a body temperature measurement taken (4.42, 1.71-11.4) and a chest X-ray (6.11, 1.07-34.9), but was lower in those complaining of chills (0.16, 0.04-0.66) and diarrhoea (0.11, 0.01-1.11). CONCLUSIONS: A majority of patients receiving medical care for acute bronchitis are given an unnecessary antibiotic prescription. The result of this study may be useful for the finding of appropriate forms of intervention for changing physicians' prescription behaviour.

Acute Disease↗

Combined effect of grain farming and smoking on lung function and the prevalence of chronic bronchitis.

The combined effect of grain farming and smoking on lung function and the prevalence of chronic bronchitis was examined in 1633 residents 20 to 65 years of age from the town of Humboldt, Saskatchewan. Multiple multivariate analysis indicated that in women grain farming and smoking had a significant synergistic effect on the values of forced expired volume in one second/forced vital capacity (FEV1/FVC), mid-expiratory flow rate (MMFR), flow rate at 50% and 25% of total volume (Vmax50 and Vmax25) after adjustment for covariates including age and height. No other factors were found to change the results. The combined effect of grain farming and smoking on lung function was not statistically significant in men. The data also show that female non-smoking grain farmers had an identical prevalence of chronic bronchitis compared with non-smoking female non-farmers, 2.0% versus 2.1%. But in women with a positive smoking history, the prevalence was 13.2% and 5.9% respectively, giving an adjusted odds ratio in grain farmers compared to non-farmers of 3.55 (95% confidence interval (Cl): 1.06-11.30). It was found that the prevalence of chronic bronchitis increased more rapidly with increasing cigarette consumption in grain farmers than in non-farmers in women. It was estimated that 85%, 72% and 66% of the prevalence of chronic bronchitis was attributed to the joint effects of grain farming and ex-smoking, light smoking (1-19 cigarettes/day) or heavy smoking (20+ cigarettes/day) status, respectively. In contrast to women, the effect of grain farming on the prevalence of chronic bronchitis was similar in men with and without a positive smoking history. Our data suggest that there is a positive interactive effect of grain farming exposure and smoking on lung function and the prevalence of chronic bronchitis in women. The difference in the interaction between men and women requires further study.

Adult↗

Chronic bronchitis and the type of cigarette smoked.

BACKGROUND: Smoking is a well known primary risk factor for chronic bronchitis. However, little is known about the relationship between different types of cigarettes smoked and chronic bronchitis. OBJECTIVE: To determine the association between chronic bronchitis and the type of cigarette smoked. METHODS: A cross-sectional prevalence study was conducted in an urban area (Pelotas) of Southern Brazil. A total of 1053 subjects aged > or = 40 years were interviewed about respiratory symptoms and some risk factors for chronic bronchitis. RESULTS: After adjustment for confounding factors, the number of daily cigarettes smoked was strongly associated with the risk of chronic bronchitis (odds ratio [OR] = 8.10, 95% CI: 4.46-14.71 for smokers of > or = 20 cigarettes per day compared to non-smokers). Among smokers, maize leaf cigarettes showed the highest risk (OR = 5.43 compared to non-smokers, 95% CI: 2.65-11.13) and filter cigarettes the lowest (OR = 2.19, 95% CI: 1.19-4.03). CONCLUSIONS: In addition to the number of cigarettes smoked, the use of maize leaf cigarettes was shown to have an important independent association with chronic bronchitis.

Adult↗

Lymphocytic bronchitis unrelated to acute graft-versus-host disease in canine marrow graft recipients.

We reviewed coded autopsy material from 71 dogs, 46 receiving allogeneic and 25 receiving autologous bone marrow transplants, to evaluate the hypothesis that lymphocytic bronchitis is associated with severe acute graft-versus-host disease (GVHD). We found no significant correlation between the presence of lymphocytic bronchitis and severe acute GVHD (P greater than 0.16). Using a binary regression model that corrected for possible confounding relationships, we failed to show a correlation between lymphocytic bronchitis and acute GVHD of each of the 3 classically affected organ systems. Also, no correlation was found between lymphocytic bronchitis and acute bacterial pneumonia (P greater than 0.32). Finally, lymphocytic bronchitis was present in autografted dogs with a prevalence at autopsy not significantly different from that of allografted dogs (P greater than 0.32). We conclude that lymphocytic bronchitis in this canine model represents nonspecific inflammation rather than acute pulmonary GVHD.

Acute Disease↗

Eosinophilic bronchitis in the workplace.

PURPOSE OF REVIEW: The purpose of this review is to report that eosinophilic bronchitis without asthma may occur as an occupational airway disease. This condition is characterized by cough that is responsive to corticosteroids and eosinophilia detectable in the sputum, without variable airflow obstruction or airway hyperresponsiveness. RECENT FINDINGS: Eosinophilic bronchitis can be regarded as an occupational respiratory disorder when it develops as a consequence of work exposures. Recently, exposure to certain occupational allergens or sensitizers, such as natural rubber latex, mushroom spores, acrylates and an epoxy resin hardener, have been reported to cause eosinophilic bronchitis without asthma. Several hypotheses have been put forward trying to explain why patients with eosinophilic bronchitis do not have airway hyperresponsiveness. It is unknown whether eosinophilic bronchitis may progress to typical occupational asthma, or if eosinophilic airway inflammation may persist when asthma symptoms and airway hyperresponsiveness have waned after the cessation of exposure to the occupational agent. SUMMARY: Eosinophilic bronchitis, like asthma, may arise from occupational exposures. The examination of induced sputum should be added to the objective monitoring of lung function during periods at work and away from work, as well as before and after specific inhalation challenges with occupational agents.

Asthma↗

Risk of depression and anxiety in employees with chronic bronchitis: the modifying effect of cigarette smoking.

OBJECTIVE: The present study evaluates whether smoking status modifies the association between chronic bronchitis and depression or anxiety in a population-based sample. Furthermore, we tested whether these associations are different in people without any respiratory complaints and those with asthma. METHODS: For this study, we used cross-sectional data form the Maastricht Cohort Study, a population-based cohort study among Dutch employees. RESULTS: In total, 7482 employees completed and returned the questionnaire (92.7%). In employees with chronic bronchitis, the prevalence of depression and anxiety was significantly higher compared with healthy employees and employees with asthma. Results indicate that the odds of having comorbid depression or anxiety for employees with chronic bronchitis compared with healthy employees is highest in current and past smokers, indicating that smoking status modifies this association. CONCLUSION: Chronic bronchitis is strongly associated with depression and anxiety. Because depression and/or anxiety may not only interfere with an attempt to stop smoking but also contribute significantly to experiencing low quality of life, it is important to consider these disorders and chronic bronchitis as different disease entities. Prospective longitudinal studies are needed to elucidate the mechanisms underlying the association among chronic bronchitis, psychiatric disorders, and cigarette smoking.

Absenteeism↗

Chronic bronchitis, cigarette smoking, and the subsequent onset of depression and anxiety: results from a prospective population-based cohort study.

OBJECTIVE: The authors used data from a prospective, population-based cohort study to examine: (a) whether the presence of chronic bronchitis predicts the subsequent onset of depression or anxiety, and (b) if the incidence of depressed or anxious cases was different for smokers compared with nonsmokers. MATERIALS AND METHODS: For studying the relation between chronic bronchitis and anxiety or depression, we used data from respectively 4468 and 4520 respondents. RESULTS: The number of incident anxious (19.1%, n = 17) and depressed (14.0%, n = 13) cases was highest in employees with chronic bronchitis compared with employees without respiratory complaints (4.3%, n = 189 and 3.3%, n = 145, respectively). The presence of chronic bronchitis was associated with a significant increase in anxious and depressed cases (odds ratio (OR) for anxiety = 5.09, 95% confidence interval (CI) 2.91, 8.89; OR for depression = 4.38, 95% CI 2.35, 8.16). The incidence of anxiety as well as depression was strongest in the smokers group (OR for anxiety = 8.94, 95% CI 4.08, 19.59; OR for depression = 7.56, 95% CI 3.37, 16.96). CONCLUSIONS: This prospective study shows significantly higher levels of anxiety as well as depression in employees with chronic bronchitis. Results also seem to indicate that smoking cigarettes modifies this association, resulting in an increased risk of depression and anxiety in employees with chronic bronchitis who smoke.

Adult↗

Circulating leukocyte adhesion molecules in stable asthma and nonobstructive chronic bronchitis.

Leukocyte adhesion molecules have been associated with airway inflammatory diseases such as asthma and obstructive chronic bronchitis. Lately, it has become possible to measure circulating forms of cell adhesion molecules (cCAMs) in body fluids. Elevated serum levels have been found in acute asthma and in obstructive chronic bronchitis. We investigated whether the patterns of cICAM-1, cVCAM-1, and cE-selectin could serve as markers for airway inflammation in stable asthma and stable nonobstructive chronic bronchitis. Small-volume bronchial lavage (BL) and serum from 15 controls, 13 asthmatics without steroid inhalation therapy, 11 asthmatics with regular steroid inhalation therapy, and 10 smokers with chronic bronchitis were analyzed. We found cICAM-1, cVCAM-1, and cE-selectin to be present in serum from patients with stable asthma and stable nonobstructive chronic bronchitis. Only cICAM-1 was found in BL fluid. No differences were seen between the subject groups for either cCAM, but levels of ECP were increased in the non-steroid-treated asthmatic group. Subject atopy or smoking did not increase the cCAM levels. In conclusion, the degree of airway inflammation in stable nonobstructive chronic bronchitis and stable asthma does not appear to be well associated with circulating ICAM-1, cVCAM-1, and cE-selectin.

Adult↗

Childhood respiratory infection and adult chronic bronchitis in England and Wales.

The high mortality from chronic bronchitis in England and Wales and the excess of urban over rural mortality are unexplained. On dividing England and Wales into 212 local authority areas a strong geographical relation was found between death rates from chronic bronchitis and emphysema in 1959-78 and infant mortality from bronchitis and pneumonia during 1921-5. It was concluded that this relation provided strong evidence of a direct casual link between acute lower respiratory infection in early childhood and chronic bronchitis in adult life. Regression analysis suggested that infection in early childhood had a greater influence than cigarette smoking in determining the geographical distribution of chronic bronchitis. National time trends reflected the influence of both factors. Chronic air pollution in adult life may be less important a cause of chronic bronchitis than previously supposed.

Adult↗

Relation between lung cancer, chronic bronchitis, and airways obstruction.

Since cigarette smoking is an important cause of lung cancer and chronic bronchitis both conditions should occur together more often in cigarette smokers than would result from chance. If they do commonly occur together then severe airways obstruction, which is often associated with chronic bronchitis, should also be often associated with lung cancer. To discover whether this were so three groups of patients were studied at the London Chest Hospital. Two hundred men and 43 women who presented with lung cancer provided information on the prevalence of defined chronic bronchitis and airways obstruction in those suffering from lung cancer. The third group consisted of 233 men presenting with defined chronic bronchitis who were kept under observation to discover how many would die from lung cancer. The results suggested that simple bronchitis and lung cancer often occur together but that obstructive bronchitis and lung cancer do not often occur together. The lack of association between lung cancer and severe airways obstruction requires an explanation.

Adult↗

Atopy: a predisposing factor for chronic bronchitis in Finland.

STUDY OBJECTIVE: To investigate the predictive value of atopy, smoking, and living in a farm environment in the development of chronic bronchitis. DESIGN: This was a cross sectional and longitudinal study. SETTING: Postal surveys carried out in Finland in 1975 and 1981. PARTICIPANTS: The study was part of the Finnish twin cohort study, which included adult twin pairs born in Finland before 1958. The cross sectional sample consisted of 18,351 subjects, including 1025 prevalent cases, and the follow up sample comprised 17,134 subjects, 553 of whom were incident cases of chronic bronchitis. MAIN RESULTS: According to the cross sectional data, chronic bronchitis was associated with atopy (relative risk 1.41) and smoking (2.43). In the follow up data, chronic bronchitis was related to atopy (1.28), smoking (2.31), and farming (1.45). CONCLUSIONS: The results confirm the earlier finding in the Finnish farming population that, in addition to smoking, atopy predisposes the development of chronic bronchitis. A farm environment was also found to be a predisposing factor. The results give further support to the "Dutch hypothesis" on the etiology of chronic bronchitis, according to which atopy is a predisposing factor.

Adolescent↗

Comparison of airway immunopathology of eosinophilic bronchitis and asthma.

BACKGROUND: Eosinophilic bronchitis is a condition characterised by a corticosteroid responsive cough, sputum eosinophilia, and normal tests of variable airflow obstruction and airway responsiveness. We performed a detailed comparative immunopathological study to test the hypothesis that the different airway function in patients with eosinophilic bronchitis and asthma reflects differences in the nature of the lower airway inflammatory response. METHODS: Exhaled nitric oxide was measured and induced sputum, bronchoscopy, bronchial wash (BW), bronchoalveolar lavage (BAL), and bronchial biopsy were performed in 16 subjects with eosinophilic bronchitis, 15 with asthma, and 14 normal controls. RESULTS: Both eosinophilic bronchitis and asthma were characterised by an induced sputum, BW and BAL eosinophilia, an increased number of epithelial and subepithelial eosinophils, and increased reticular basement membrane thickness. The median concentration of exhaled nitric oxide was higher in those with eosinophilic bronchitis (12 ppb) or asthma (8.5 ppb) than normal controls (2 ppb) (95% CI of the difference 5 to 16, p<0.0001 and 2 to 11.3, p=0.004, respectively). There were no group differences in epithelial integrity or the number of subepithelial T lymphocytes, mast cells or macrophages. CONCLUSION: With the exception of our previously reported association of smooth muscle mast cell infiltration with asthma, the immunopathology of eosinophilic bronchitis and asthma are similar which suggests that eosinophilic airway inflammation, increased exhaled nitric oxide, and increased basement membrane thickening are regulated independently of airway hyperresponsiveness.

Asthma↗

Prevalence and risk factors for chronic bronchitis in Pelotas, RS, Brazil: a population-based study.

BACKGROUND: Chronic bronchitis causes high morbidity and mortality throughout the world. It is basically a preventable disease. However, few population based studies of chronic bronchitis have been carried out in less developed countries. METHODS: A population based cross sectional survey was conducted to determine the prevalence of chronic bronchitis and associated risk factors in an urban area (Pelotas) of southern Brazil. 1053 subjects aged 40 years and over (90.3% of eligible subjects) were interviewed using the ATS-DLD-78 questionnaire. RESULTS: Of the subjects interviewed 12.7% were classified as having chronic bronchitis. In univariate analyses a significant increase in the relative odds of chronic bronchitis was seen in men (OR = 2.17, 95% CI 1.50 to 3.13), low family income (OR = 2.60, 95% CI 1.47 to 4.47 for lowest quartile), low schooling (OR = 4.65, 95% CI 2.36 to 9.18 for those with no schooling), smoking habits (OR = 6.92, 95% CI 4.22 to 11.36 for smokers of 20 or more cigarettes per day), high occupational exposure to dust (OR = 2.48, 95% CI 1.56 to 3.94), inadequate housing (OR = 2.09, 95% CI 1.22 to 3.58), high level of indoor air pollution (OR = 1.86, 95% CI 1.16 to 2.99), and reported childhood respiratory illnesses (OR = 2.08, 95% CI 1.25 to 3.49). Multiple logistic regression resulted in the identification of the following independent risk factors: family income (OR = 1.99, 95% CI 1.04 to 3.81 for subjects in the lowest quartile compared with those in the highest quartile), schooling (OR = 5.60, 95% CI 2.52 to 12.45 for subjects with no schooling compared with those with nine or more years), smoking (OR = 8.10, 95% CI 4.46 to 14.71 for smokers of 20 or more cigarettes per day compared with non-smokers), and history of major respiratory illnesses in childhood (OR = 2.16, 95% CI 1.20 to 3.85). CONCLUSIONS: Low family income, poor schooling, smoking, and childhood respiratory illnesses were significantly associated with chronic bronchitis.

Adult↗

15(S)-HETE modulates LTB(4) production and neutrophil chemotaxis in chronic bronchitis.

We evaluated the levels of 15(S)-hydroxyeicosatetraenoic acid [15(S)-HETE] and the expression of 15-lipoxygenase (15-LO) mRNA in induced sputum obtained from 10 control and 15 chronic bronchitis subjects. 15(S)-HETE was evaluated by reverse phase high-performance liquid chromatography separation followed by specific RIA. 15-LO mRNA expression was determined by primed in situ labeling. The levels of both soluble and cell-associated 15(S)-HETE resulted significantly higher in chronic bronchitis than in control subjects. The percentage of cells expressing 15-LO mRNA was significantly higher in chronic bronchitis than in control subjects (P < 0.01). Double staining for specific cell type markers and 15-LO mRNA showed macrophages and neutrophils positive for 15-LO, whereas similar staining of peripheral blood neutrophils did not show evidence for 15-LO expression, suggesting that expression of 15-LO in neutrophils takes place on migration into the airways. Because 15(S)-HETE inversely correlated with the percentage of neutrophils in sputum of chronic bronchitis subjects, we studied the effect of 15(S)-HETE on leukotriene B(4) (LTB(4)) production in vitro and evaluated the concentration of LTB(4) in induced sputum and the contribution of LTB(4) to the chemotactic activity of induced sputum samples ex vivo. The results obtained indicate that macrophages and neutrophils present within the airways of chronic bronchitis subjects express 15-LO mRNA; increased basal levels of 15(S)-HETE may contribute to modulate, through the inhibition of 5-lipoxygenase metabolites production, neutrophil infiltration and airway inflammation associated with chronic bronchitis.

Adult↗

Transforming growth factor-beta expression in mucosal biopsies in asthma and chronic bronchitis.

We assessed whether transforming growth factor-beta (TGF-beta), a fibrogenic growth factor, may be involved in remodeling of asthma and chronic bronchitis; its expression was compared with that of epidermal growth factor (EGF) and granulocyte macrophage colony-stimulating factor (GM-CSF) in bronchial mucosal biopsies from 13 normal subjects, 24 asthmatics, and 19 patients with chronic bronchitis. TGF-beta immunoreactivity was highly increased in epithelium and submucosa of those with bronchitis and to a lesser extent in asthmatics. By comparison, with normal subjects, EGF immunoreactivity was significantly increased in the epithelium of bronchitic subjects and submucosa of asthmatics, and, GM-CSF immunoreactivity was increased in both epithelial and submucosal cells of asthmatics and to a lesser extent in submucosa of bronchitics. A significant correlation was found between the number of epithelial or submucosal cells expressing TGF-beta in both asthma and chronic bronchitis and basement membrane thickness and fibroblast number. No such correlation was found for EGF or GM-CSF. in situ hybridization for TGF-beta 1 mRNA confirmed the results obtained by immunohistochemistry. By combining in situ hybridization and immunohistochemistry, it was found that eosinophils and fibroblasts were synthetizing TGF-beta in asthma and bronchitis. These data suggest that TGF-beta, but not EGF or GM-CSF, is involved in airways remodeling in asthma and chronic bronchitis.

Adolescent↗