CD8+ T-lymphocytes in peripheral airways of smokers with chronic obstructive pulmonary disease

To investigate whether the inflammatory process in peripheral airways is different in smokers who develop symptoms of chronic bronchitis and chronic airflow limitation and in asymptomatic smokers who do not develop chronic airflow limitation, we examined surgical specimens obtained from 16 smokers undergoing lung resection for localized pulmonary lesions. Nine had symptoms of chronic bronchitis and chronic airflow limitation and seven were asymptomatic with normal lung function. In peripheral airways, immunohistochemical methods were performed to identify neutrophils, macrophages, CD4+ and CD8+ T-lymphocytes infiltrating the airway wall, and morphometric methods were used to measure the internal perimeter, the airway wall area, and the smooth muscle area. The number of CD8+ T-lymphocytes and the smooth muscle area were increased in smokers with symptoms of chronic bronchitis and chronic airflow limitation as compared with asymptomatic smokers with normal lung function, while the number of neutrophils, macrophages, and CD4+ T-lymphocytes were similar in the two groups of subjects examined. We concluded that smokers who develop symptoms of chronic bronchitis and chronic airflow limitation have an increased number of CD8+ T-lymphocytes and an increased smooth muscle area in the peripheral airways as compared with asymptomatic smokers with normal lung function, supporting the important role of CD8+ T-lymphocytes and airway remodeling in the pathogenesis of chronic obstructive pulmonary disease.

Chronic obstructive pulmonary disease international guidelines

Although chronic obstructive pulmonary disease (COPD) has a public health importance similar to asthma, it has received less attention. The first guideline on the management of COPD was released in 1987 by the American Thoracic Society. In 1992 the Canadian Thoracic Society released its guidelines. In 1995 the European Respiratory Society and the Thoracic Society of Australia and New Zealand released their guidelines and the American Thoracic Society updated and expand its COPD guidelines. All these documents were followed in 1997 by the guidelines developed by the British Thoracic Society. These COPD guidelines show many similarities but also have some interesting differences. The aim of this paper is to review these similarities and discrepancies. Like all guidelines, COPD guidelines suffer from the limited amount of evidence-based medicine supporting them, a limitation that, however, provides a strong stimulus for further research.

Hypo-osmolar aerosol induces hyperventilation in chronic non-asthmatic rhinitics

The effect of a hypo-osmolar aerosol on transcutaneous O2 and CO2 time course (PtcO2, PtcCO2) was investigated in subjects affected by chronic non-atopic rhinitis, without any history of asthmatic symptoms and no airways hyper-responsiveness. Twelve normal subjects and 12 subjects affected by chronic idiopathic rhinitis, who had normal responsiveness to both hypo-osmolar aerosol and methacholine challenge as measured by the decrease in FEV1 (mean FEV1 decrease = 5% and PC20 > 16 mg, respectively) were studied. By means of a transcutaneous mono-electrode, it was possible to study the time course of PtcO2 and PtcCO2 during and after a 5-min inhalation of ultrasonically nebulized distilled water (output 2 ml/min-1). A significant decrease in PtcCO2 and increase in PtcO2 were observed during the challenge in rhinitics as compared with normal subjects [maximum decrease and maximum increase expressed as mean value (+/- SD) were -22% (+/- 6.9) and +12.6% (+/- 7.2), respectively]. No significant changes in either PtcCO2 and PtcO2 were observed after the test. The results of this study suggest that patients affected by idiopathic chronic rhinitis with absence of bronchial hyper-responsiveness may present a hyperventilatory response to the inhalation of hypo-osmolar aerosol; the mechanism of such a response might be due to an upregulation of the irritant receptors of the upper airways.

Increased VIP-positive nerve fibers in the mucous glands of subjects with chronic bronchitis

The presence and distribution of neuropeptide-containing nerves within bronchial surgical specimens has been investigated in bronchitic (n = 12) and in nonbronchitic subjects (n = 7). Lung tissue, obtained from patients undergoing thoracotomy for limited lung lesions, was processed immediately and analyzed for nerves using the streptavidin-biotin complex peroxidase method with antisera to the neural marker protein gene product 9.5 (PGP 9.5) and the neuropeptides vasoactive intestinal peptide (VIP), substance P (SP), calcitonin-gene related peptide (CGRP). There were no significant differences between the two groups with respect to the density of PGP 9.5-, SP-, or CGRP-positive nerves in both the locations assessed (smooth muscle layer and glands). The density of VIP-positive nerves was significantly higher in the glands of bronchitic than in nonbronchitic subjects. A negative relationship was found between the presence of airway inflammation, as indexed by mononuclear cell tissue infiltration, and the density of PGP 9.5-positive nerves in both smooth muscle and glands. Likewise, a relationship was found between the smoking history (packs/yr and age of onset of smoking) and the density of VIP-positive nerves in glands. These findings support a role for VIP in the hallmark of chronic bronchitis, i.e., sputum production.

Inflammatory cells in the bronchial glands of smokers with chronic bronchitis

To characterize the inflammatory process in the bronchial glands of smokers with chronic sputum production, we examined lobar bronchi from 18 subjects undergoing lung resection for localized pulmonary lesions, all with a history of cigarette smoking. Nine of the subjects had symptoms of chronic bronchitis and chronic airflow obstruction, and nine were asymptomatic, with normal lung function. The number of neutrophils, eosinophils, mast cells, macrophages, CD4+ and CD8+ T-lymphocytes, and the ratio of CD4+ to CD8+ cells were assessed in the bronchial glands, epithelium, and submucosa. Cells were identified through immunohistochemistry. Smokers with symptoms of chronic bronchitis had an increased number of neutrophils (p = 0.01) and macrophages (p = 0.03) and a decreased CD4+/CD8+ ratio (p = 0.01) in the bronchial glands as compared with asymptomatic smokers. Chronic bronchitic smokers also had an increased number of epithelial neutrophils (p = 0.04), whereas the numbers of macrophages and CD4+ and CD8+ T-lymphocytes in the epithelium and submucosa were similar in the two groups of smokers. No differences in numbers of eosinophils or mast cells were observed between bronchitic and asymptomatic smokers in any of the compartments examined. In conclusion, smokers with chronic sputum production have an increased infiltration of neutrophils and macrophages and an increased proportion of CD8+ T-lymphocytes in their bronchial glands, supporting the important role of bronchial-gland inflammation in the pathogenesis of chronic bronchitis.

Subcutaneous emphysema of the chest wall: a case with unusual presentation

Subcutaneous emphysema (SE) is the presence of air or other gas in the subcutaneous tissue and is generally associated with pneumothorax and/or pneumomediastinum. We describe an unusual presentation of SE of the chest wall without radiological evidence of pneumothorax or pneumomediastinum, which aetiopathogenesis remains open to several hypotheses in spite of an accurate clinical study.

Effect of subchronic in vivo exposure to nitrogen dioxide on lung tissue inflammation, airway microvascular leakage, and in vitro bronchial muscle responsiveness in rats

OBJECTIVES

In a previous study on bronchoalveolar lavage fluid from rats exposed in vivo for seven days to 10 ppm nitrogen dioxide (NO2), it has been shown that there is an influx of macrophages into the airways. The present study investigated the effect of seven day exposure to 10 ppm NO2, on: (a) lung tissue inflammation and morphology; (b) airway microvascular leakage; (c) in vitro contractile response of main bronchi.

METHODS

Lung tissue was studied by light microscopy, after fixing the lungs by inflation with 4% formalin at a pressure of 20 cm H2O. Microvascular leakage was measured by extravasation of Evans blue dye in the larynx, trachea, main bronchi, and intrapulmonary airways. Smooth muscle responsiveness was evaluated by concentration-responses curves to acetylcholine (10(-9)-10(-3) M), serotonin (10(-9)-10(-4) M), and voltage-response curves (12-28 V) to electrical field stimulation.

RESULTS

Histology showed an increased total inflammation at the level of respiratory bronchioles and alveoli. No influx of inflammatory cells was found in the main bronchi. A loss of cilia in the epithelium of small airways and ectasia of alveolar capillaries was also found. By contrast, no alterations to microvascular permeability or modification of bronchial smooth muscle responsiveness was found.

CONCLUSIONS

Subchronic exposure to 10 ppm NO2 causes airway inflammation and structural damage, but does not cause any persistent alteration to microvascular permeability or bronchial smooth muscle responsiveness in rats.

Efficacy of topical tuaminoheptane combined with N-acetyl-cysteine in reducing nasal resistance. A double-blind rhinomanometric study versus xylometazoline and placebo

The aim of this study was to functionally evaluate the decongestant effect of a topical intranasal drug (Rhinofluimucil consisting of tuaminoheptane sulphate (CAS 6411-75-2, THS), a vasoconstrictor, combined with N-acetyl-cysteine (CAS 616-91-1, NAC). This was a double-blind randomized study, versus both xylometazoline and placebo. 18 subjects (8M and 10F, aged 20-47 years), unaffected by any rhinitic pathology, underwent anterior rhinomanometry. Following the basal evaluation (T0), subjects were randomly divided into three groups and subjected, in a double-blind manner, to nasal instillations (2 puffs per nostril) of THS/NAC (R), xylometazoline (O) and saline solution (P), respectively. Rhinomanometry was repeated after 5, 10 and 20 min (T5, T10, T20). Resistance and flow were measured in both nostrils at a pressure gradient of 150 Pa. After R and O nasal resistance significantly decreased from 0.30 Pa to 0.19 Pa and from 0.31 Pa to 0.17 Pa, respectively, and flow significantly increased; no effects were observed with placebo. In this study, THS/NAC showed rapid decongestant properties, with a significant decrease of resistance and increase of inspiratory flow. The same finding was observed with xylometazoline, but not with the placebo. The decongestant effect was rapid: it could already be observed at T5, and remained constant up to T20 without any rebound effect.

Methotrexate in the treatment of systemic glucocorticoid-dependent severe persistent asthma: a word of caution

Methotrexate should not be prescribed to every systemic glucocorticoid-dependent asthmatic. In fact, while methotrexate may be advantageous in selected patients, every attempt to control asthma with regular anti-asthma agents should be made. Most studies on the effects of methotrexate in the treatment of systemic glucocorticoid-dependent asthmatics include small numbers of patients and are all of relatively short duration. Thus, large long-term multicentre trials are urgently needed. In these studies, a uniform accepted definition of systemic glucocorticoid-dependent asthmatics should be used. For the time being, we reinforce the recommendation of the NHLBI/ WHO panel that methotrexate and other systemic glucocorticoid sparing drugs should be considered experimental medications, and used only in selected patients under the supervision of an asthma specialist with previous experimental experience.

Association between toluene diisocyanate-induced asthma and DQB1 markers: a possible role for aspartic acid at position 57

Toluene diisocyanate (TDI) is the most common cause of occupational asthma in western countries. The aim of this study was to investigate whether genetic factors are involved in toluene diisocyanate-induced asthma. We studied the frequency of human leucocyte antigen (HLA) class II genetic markers in three groups of subjects: 1) subjects with TDI-induced asthma (n = 30); 2) exposed subjects with no history of TDI-induced asthma (n = 12); and 3) normal subjects not exposed to TDI (n = 126). Venous blood samples were collected from the three groups and the polymorphic second exon of DQA and DQB genes was amplified by the polymerase chain reaction (PCR) method. Evaluation of HLA class II gene products in TDI-induced asthma cases showed a positive association with HLA-DQB1 * 0503 and a negative association with HLA-DQB1 * 0501 alleles, which differed at residue 57 for a single amino acid, i.e. aspartic acid in DQB1 * 0503 and valine in DQB1 * 0501. No significant difference was found in the distribution of DQA1 alleles between asthmatics and controls. Our results confirm the hypothesis that HLA-DQB1 * 0503 has a role in conferring susceptibility to TDI-induced asthma and that residue 57 of HLA-DQB1 is a potentially critical location.

Xanthine oxidase activity in bronchoalveolar lavage fluid from patients with chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a serious respiratory pathology characterized by irreversible limitation of expiratory flow and includes chronic obstructive bronchitis, chronic airflow limitation, and emphysema. To determine whether xanthine oxidase activity increased in the airspaces of COPD patients, we examined bronchoalveolar lavage fluid (BAL) from COPD patients recruited during a 2-year clinical study. Filtered BAL supernatant from COPD patients and healthy nonsmoking controls was examined by fluorometric analysis of DNA unwinding (FADU) and spectrophotometric assays (cytochrome c reduction kinetics and uric acid kinetics). Compared to controls, filtered BAL supernatant of subjects with COPD exhibited a detectable clastogenic activity probably related to superoxide production. The method of BAL preparation as an acellular system strongly suggests that superoxide production may be due to xanthine oxidase activity.

Oral vs inhaled asthma therapy. Pros, cons and combinations

A number of oral and inhaled drugs are available for the long term management of patients with persistent asthma, yet the disease continues to be associated with significant morbidity and mortality. Over the past years, inhaled glucocorticoids have become established as a cornerstone of maintenance therapy because of their demonstrated clinical efficacy, ability to reduce bronchial inflammation and good tolerability. Other inhaled drugs (e.g. sodium cromoglycate, nedocromil, long-acting beta 2 agonists) also play a role in the long term treatment of patients with asthma. However, many patients (especially children and the elderly) find inhalers difficult to use, and poor inhalation technique can affect the amount of drug reaching the lungs and response to therapy. Oral drug administration is simple, but, until recently, oral asthma therapy has primarily consisted of sustained-release theophylline and glucocorticoids. Theophylline has a narrow therapeutic index, necessitating regular monitoring of serum drug concentrations, and long term oral glucocorticoid therapy is associated with potentially serious adverse events including osteoporosis with bone fracture. The recent development of orally administered leukotriene receptor antagonists (e.g. zafirlukast) and 5-lipoxygenase inhibitors (e.g. zileuton) offers novel mechanisms of action and potential solutions to compliance issues associated with regular administration of inhaled asthma therapy. These drugs have demonstrated efficacy as maintenance therapy in patients with asthma and, importantly, lack the adverse effects associated with long term systemic glucocorticoid therapy. Further clinical trials and the increasing use of these new therapies will help to establish the precise role of orally administered leukotriene receptor antagonists and 5-lipoxygenase inhibitors in the long term management of patients with asthma.

In-vitro exposure of guinea pig main bronchi to 2.5 ppm of nitrogen dioxide does not alter airway smooth muscle response

In order to investigate whether the oxidant airborne pollutant nitrogen dioxide (NO2) affects airway smooth muscle responsiveness, the contractile response of guinea pig main bronchi after in vitro exposure to 2.5 ppm of nitrogen dioxide was studied. Main bronchi were cannulated and exposed for 2 or 4 h to a constant flow of either NO2 or air. After exposure, bronchial rings were obtained and placed in a 37 degrees C jacketed organ bath filled with Krebs-Henseleit solution. Concentration-response curves were performed for acetylcholine (10(-9)-10(-3) M), substance P (10(-9)-10(-4) M), and neurokinin A (10(-10)-10(-5) M), and voltage-response curves (12-28 V) were performed for electrical field stimulation. There was no significant difference in either the smooth muscle maximal contractile response, or sensitivity between the bronchi exposed to NO2 and those exposed to air. We conclude that in vitro exposure to 2.5 ppm of NO2 does not alter airway smooth muscle responsiveness in guinea pigs.

Airway eosinophilia in chronic bronchitis during exacerbations

To examine the nature and the degree of airway inflammation in chronic bronchitis during exacerbations, bronchial biopsies and sputum were obtained in 11 subjects with chronic bronchitis examined during an exacerbation, and in 12 subjects with chronic bronchitis examined under baseline conditions. All subjects were nonatopic. Lobar bronchial biopsies were assessed using histochemical and immunohistochemical techniques, and sputum was examined for differential cell counts of leukocytes. Subjects with bronchitis during exacerbations had, on average, 30-fold more eosinophils in their bronchial biopsies than did those examined under baseline conditions (p < 0.001). Although to a lesser extent, the numbers of neutrophils (p < 0.01), T-lymphocytes (CD3) (p < 0.05), VLA-1-positive cells (p < 0.01), and TNF-alpha positive cells (p < 0.05) were also increased during exacerbations. By contrast, the T-lymphocyte subpopulations (CD4 and CD8) and the numbers of macrophages, mast cells, IL-2R-positive cells, and IL-1 beta-positive cells were similar in the two groups of subjects, as well as the percentages of ICAM-1- and E-selectin-positive vessels. Eosinophils were also increased in sputum of subjects with exacerbations when compared with those examined under baseline conditions (p < 0.05). In conclusion, exacerbations of chronic bronchitis are associated with a marked airway eosinophilia and with a milder increase in the number of neutrophils, activated T-lymphocytes, and TNF-alpha-positive cells in the bronchial mucosa.

Pidotimod activity against chronic bronchitis exacerbations

The efficacy of pidotimod ((R)-3-[(S)-(5-oxo-2-pyrrolidinyl) carbonyl]-thiazolidine-4-carboxylic acid, PGT/1A, CAS 121808-62-6) in the management of infectious exacerbations of chronic bronchitis was evaluated in a double-blind, placebo-controlled study in parallel groups over 5 months (60 days of treatment and 90 days of follow-up). The study enrolled 580 patients, of whom 514 could be evaluated. The pidotimod group had fewer and shorter infectious episodes, fewer days of antibiotic therapy and fewer days unable to undertake normal activities. The difference vs. placebo was significant during the follow-up period and, in those subjects with a less severe history, during the treatment period also. Pidotimod was well tolerated.

In vitro exposure to nitrogen dioxide (NO2) does not alter bronchial smooth muscle responsiveness in ovalbumin-sensitized guinea-pigs

The aim of this study was to investigate whether in vitro exposure to NO2 affects responsiveness in ovalbumin-sensitized guinea-pig bronchi. Twenty-three animals were sensitized by three weekly intraperitoneal injections of 1 mg ovalbumin in saline with Freund's adjuvant; twenty-one control guinea-pigs received the diluent alone. From each animal, the two main bronchi were obtained and cannulated, then exposed in vitro to a constant intraluminal flow of: (i) either air or 2.5 ppm NO2 with four spikes of 10 ppm NO2 for 2 h; (ii) either air or 10 ppm NO2 for 4 h. A bronchial ring obtained from each animal before exposure was kept in aerated Krebs-Henseleit solution. Rings from bronchi exposed to air, NO2, or kept in Krebs solution were studied isometrically. We performed overall and non-adrenergic non-cholinergic voltage-response curves to electrical field stimulation, concentration-response curves to acetylcholine and to neurokinin A, followed by administration of 10 mg/ml ovalbumin. We did not find any significant difference in bronchial smooth muscle responsiveness between nonexposed, air-exposed and NO2-exposed bronchi, as well as between bronchi from control and sensitized animals. We conclude that in vitro exposure to NO2 does not alter bronchial smooth muscle responsiveness to either specific or non-specific stimuli.

Structural aspects of airway inflammation in COPD

Descriptions of pathology of chronic bronchitis in the past have been mainly focused on mucous gland hypertrophy, since this was considered the morphologic basis of the disease, but more recent studies have suggested a pathogenetic role for airway inflammation in subjects with chronic bronchitis. In the present review, we briefly summarize the results of these latter studies, which describe the nature of airway inflammation and the state of activation of inflammatory cells in the bronchial mucosa of subjects with chronic bronchitis.

Oxygen radical scavengers inhibit clastogenic activity induced by sonication of human serum

Clastogenic factors (CF) are diffusible molecules that damage DNA. They are generated within biological media by a variety of physical and chemical stimuli. Their nature and mechanism of action remain largely unknown. Clastogenic activity can be experimentally generated by pulsed ultrasound treatment of human serum. To investigate whether oxygen radicals are involved in the clastogenic activity induced by sonication of human serum, we examined the effects on such clastogenic activity of different oxygen radical scavengers added to human serum before and after sonication. Human serum was sonicated for 50 min at 24 microW/cm2 by pulsed ultrasound. The clastogenic activity of sonicated human serum was examined in the presence or absence of oxygen radical scavengers by measuring the amount of DNA damage induced in autologous human lymphocytes, assessed with the fluorometric analysis of DNA unwinding (FADU). Sonication of human serum generated significant DNA damage in autologous lymphocytes (DNA unwinding averaged 31.79% +/- 2.1 after sonication vs. 12.82% +/- 2.6 in the controls, p < 0.005). Superoxide dismutase (SOD; 500 I.U./ml), catalase (500 I.U./ml), mannitol (50 mM), and glutathione (50 mM) completely prevented DNA damage when added before serum sonication, whereas only mannitol (86%) and glutathione (90%) almost completely inhibited DNA damage when added after sonication. SOD and catalase had only a partial inhibitory effect when added after sonication (49% and 63%, respectively). The prevention of DNA damage was also obtained by an association of subliminal amounts of glutathione (20 mM) and vitamin E (1 I.U./ml). These results suggest that the clastogenic activity generated by sonication of human serum is mediated by oxygen radicals.

Mechanisms and pathology of occupational asthma

Since the pathogenesis and the pathological features of occupational asthma are similar to those of nonoccupational asthma, the former represents a very useful model for the investigation of the pathogenesis of asthma in general. More than one mechanism may be operative in occupational asthma. Among the mechanisms proposed, immunological mechanisms and airway inflammation play an important role. There is evidence to confirm that T-lymphocyte activation and local accumulation in the bronchial wall of activated eosinophils occurs in asthma of diverse aetiology, i.e. immunoglobulin E (IgE)-mediated, occupational and intrinsic. Neurogenic pathways should be further investigated as a potential mechanism of modulation and amplification of airway inflammation in occupational asthma.

Upregulation of adhesion molecules in the bronchial mucosa of subjects with chronic obstructive bronchitis

To determine whether adhesion molecules and cytokines are upregulated in the bronchial mucosa of chronic bronchitics, we obtained bronchial biopsies in 16 chronic bronchitics, in eight asymptomatic smokers, and in seven normal nonsmoking subjects. Bronchial biopsies were examined by immunohistochemistry to identify the expression of E-selectin and intercellular adhesion molecular-1 (ICAM-1) on vessels and on bronchial epithelium, and the expression of interleukin-1 beta (IL-1 beta), tumor necrosis factor-alpha (TNF-alpha), neutrophil elastase, and eosinophil cationic protein (EG-2) on cells in the submucosa. Chronic bronchitics had an increased number of E-selectin-positive vessels when compared with both asymptomatic smokers (p < 0.05) and normal subjects (p < 0.01). The numbers of ICAM-1-positive vessels, neutrophils, and IL-1 beta, TNF-alpha-, and EG-2-positive cells were not significantly different in the three groups of subjects examined. When the bronchitic group was divided according to the presence or absence of airway obstruction, the increased number of E-selectin-positive vessels persisted only in bronchitics with airway obstruction, who also had an increased expression of ICAM-1 on basal epithelial cells. We concluded that in the bronchial mucosa of chronic bronchitics with airway obstruction, there is an increased expression of E-selectin on vessels and of ICAM-1 on basal epithelial cells, suggesting the involvement of these adhesion molecules in the pathogenesis of the disease.