Metabolic pathways in immune senescence and inflammaging: Novel therapeutic strategy for chronic inflammatory lung diseases. An EAACI position paper from the Task Force for Immunopharmacology.

The accumulation of senescent cells drives inflammaging and increases morbidity of chronic inflammatory lung diseases. Immune responses are built upon dynamic changes in cell metabolism that supply energy and substrates for cell proliferation, differentiation, and activation. Metabolic changes imposed by environmental stress and inflammation on immune cells and tissue microenvironment are thus chiefly involved in the pathophysiology of allergic and other immune-driven diseases. Altered cell metabolism is also a hallmark of cell senescence, a condition characterized by loss of proliferative activity in cells that remain metabolically active. Accelerated senescence can be triggered by acute or chronic stress and inflammatory responses. In contrast, replicative senescence occurs as part of the physiological aging process and has protective roles in cancer surveillance and wound healing. Importantly, cell senescence can also change or hamper response to diverse therapeutic treatments. Understanding the metabolic pathways of senescence in immune and structural cells is therefore critical to detect, prevent, or revert detrimental aspects of senescence-related immunopathology, by developing specific diagnostics and targeted therapies. In this paper, we review the main changes and metabolic alterations occurring in senescent immune cells (macrophages, B cells, T cells). Subsequently, we present the metabolic footprints described in translational studies in patients with chronic asthma and chronic obstructive pulmonary disease (COPD), and review the ongoing preclinical studies and clinical trials of therapeutic approaches aiming at targeting metabolic pathways to antagonize pathological senescence. Because this is a recently emerging field in allergy and clinical immunology, a better understanding of the metabolic profile of the complex landscape of cell senescence is needed. The progress achieved so far is already providing opportunities for new therapies, as well as for strategies aimed at disease prevention and supporting healthy aging.

Th2 cytokines impair innate immune responses to rhinovirus in respiratory epithelial cells.

BACKGROUND: Asthma and other Th2 inflammatory conditions have been associated with increased susceptibility to viral infections. The mechanisms by which Th2 cytokines can influence immune responses to infections are largely unknown. METHODS: We measured the effects of Th2 cytokines (IL-4 and IL-13) on bronchial epithelial cell innate immune antiviral responses by assessing interferon (IFN-ß and IFN-λ1) induction following rhinovirus (RV)-16 infection. We also investigated the modulatory effects of Th2 cytokines on Toll-like receptor 3 (TLR3), interferon-responsive factor 3 (IRF3) and nuclear factor (NF)-kB, that is key molecules and transcription factors involved in the rhinovirus-induced interferon production and inflammatory cascade. Pharmacological and redox modulation of these pathways was also assessed. RESULTS: Th2 cytokines impaired RV-16-induced interferon production, increased rhinovirus replication and impaired TLR3 expression in bronchial epithelial cells. These results were replicated in vivo: we found increased IL-4 mRNA levels in nasal epithelial cells from nasal brushing of atopic rhinitis patients and a parallel reduction in TLR3 expression and increased RV-16 replication compared to nonatopic subjects. Mechanistically, Th2 cytokines impaired RV-16-induced activation of IRF3, but had no effects on RV-16-induced NF-kB activation in bronchial epithelial cell cultures. N-acetylcysteine and phosphoinositide 3-kinase (PI3K) inhibitor restored the inhibitory effects of Th2 cytokines over RV-16-induced activation of IRF3. CONCLUSIONS: IL-4 and IL-13, through inhibition of TLR3 expression and signalling (IRF3), impair immune response to RV-16 infection. These data suggest that Th2 conditions increase susceptibility to infections and identify pharmacological approaches with potential to restore impaired immune response in these conditions.

Increased expression of CCL4/MIP-1ß in CD8+ cells and CD4+ cells in sarcoidosis.

Sarcoidosis is a granulomatous disease with an increased accumulation of T cells in lungs as a result of on-site proliferation and chemotaxis induced by chemokines. It has already been demonstrated that CCL3-5 levels were increased in BAL fluid of sarcoidosis patients. To analyze the expression of CCL3-5 chemokines by T-cell subtypes (CD4+, CD8+, Th1, Th2, Tc1 or Tc2) in the lungs of sarcoidosis patients, fifteen untreated sarcoidosis patients and eighteen control subjects were enrolled in this study. CD4+ and CD8+ cells were isolated from BAL fluid by positive magnetic selection. The expression of CCL3-5 and other cytokines in CD4+ and CD8+ cells were measured by flow cytometry. The percentage of CD4+ or CD8+ cells expressing CCL4 were significantly higher in sarcoidosis patients (22.3% and 58.1%) compared to those seen in healthy subjects (11.1% and 16.5%, P = 0.04 and P = 0.02, respectively). In addition, the expression of CCL3, CCL4 and CCL5 was significantly elevated in CD8+ cells (8.9%, 58.1% and 2.1%) compared to CD4+ cells (2.1%, 22.3% and 0.7%; P = 0.04, P = 0.009 and P = 0.04, respectively), whereas CCL4 was expressed by significantly more Tc1 than Th1 cells in sarcoidosis patients (P = 0.006). Our study shows the possible role of CD8+ cells and CD4+ cells in recruiting T cells to the site of inflammation in sarcoidosis through the release of CCL4, either alone or together with Th1/Tc1-associated cytokines.

Severe pneumonia after intravesical BCG instillation in a patient with invasive bladder cancer: case report and literature review.

We present here the case of a 66 year old man with a severe bilateral community acquired pneumonia secondary to dissemination after an intravesical instillation of bacilllus Calmette-Guerin (BCG). Diagnosis was based on positive polymerase chain reaction (PCR) for mycobacterium tuberculosis complex in bronchoalveolar lavage and on the finding on transbronchial biopsy of non necrotising granulomas histopathologically similar to the granulomas found in bladder biopsies. These findings were confirmed using a validated real time PCR assay demonstrating the presence of the BCG genome in transbronchial and bladder biopsies.

Bronchial glomus tumor mimicking a COPD exacerbation.

We report the case of a glomus tumor originating in the left main bronchus diagnosed in a 79 year old Caucasian man. A glomus tumor is an extremely rare neoplasm in the bronchi with nonspecific clinical features. Bronchoscopy allows the diagnosis through biopsy and subsequent histopathological examination of the tissue and in selected cases may represent a valid alternative to surgery permitting a radical tumor excision.

Rhinovirus induces MUC5AC in a human infection model and in vitro via NF-κB and EGFR pathways.

Rhinovirus (RV) infections are the major cause of asthma exacerbations, the major cause of morbidity and mortality in asthma. MUC5AC is the major mucin produced by bronchial epithelial cells. Whether RV infection upregulates MUC5AC in vivo is unknown and the molecular mechanisms involved are incompletely understood. We investigated RV induction of MUC5AC in vivo and in vitro to identify targets for development of new therapies for asthma exacerbations. RV infection increased MUC5AC release in normal and asthmatic volunteers experimentally infected with RV-16, and in asthmatic, but not normal, subjects, this was related to virus load. Bronchial epithelial cells were confirmed a source of MUC5AC in vivo. RV induction of MUC5AC in bronchial epithelial cells in vitro occurred via nuclear factor-κB-dependent induction of matrix metalloproteinase-mediated transforming growth factor-α release, thereby activating an epidermal growth factor receptor-dependent cascade culminating, via mitogen-activated protein kinase activation, in specificity protein-1 transactivation of the MUC5AC promoter. RV induction of MUC5AC may be an important mechanism in RV-induced asthma exacerbations in vivo. Revealing the complex serial signalling cascade involved identifies targets for development of pharmacologic intervention to treat mucus hypersecretion in RV-induced illness.

Association of increased CCL5 and CXCL7 chemokine expression with neutrophil activation in severe stable COPD.

BACKGROUND: Increased numbers of activated neutrophils have been reported in the bronchial mucosa of patients with stable chronic obstructive pulmonary disease (COPD), particularly in severe disease. OBJECTIVES: To investigate the expression of neutrophilic chemokines and adhesion molecules in bronchial biopsies from patients with stable COPD of different severity (GOLD stages I-IV) compared with age-matched control subjects, smokers with normal lung function and never smokers. METHODS: The expression of CCL5, CXCL1, 5, 6, 7 and 8, CXCR1, CXCR2, CD11b and CD44 was measured in the bronchial mucosa using immunohistochemistry, confocal immunofluorescence, real-time quantitative polymerase chain reaction (RT-QPCR) and Western blotting (WB). RESULTS: The numbers of CCL5+ epithelial cells and CCL5+ and CXCL7+ immunostained cells were increased in the bronchial submucosa of patients with stable severe COPD compared with control never smokers and smokers with normal lung function. This was also confirmed at the level of mRNA expression. The numbers of CCL5+ cells in the submucosa of patients with COPD were 2-15 times higher than any other chemokines. There was no correlation between the number of these cells and the number of neutrophils in the bronchial submucosa. Compared with control smokers, the percentage of neutrophils co-expressing CD11b and CD44 receptors was significantly increased in the submucosa of patients with COPD. CONCLUSION: The increased expression of CCL5 and CXCL7 in the bronchial mucosa of patients with stable COPD, together with an increased expression of extracellular matrix-binding receptors on neutrophils, may be involved in the pathogenesis of COPD.

T helper type 17-related cytokine expression is increased in the bronchial mucosa of stable chronic obstructive pulmonary disease patients.

There are increased numbers of activated T lymphocytes in the bronchial mucosa of stable chronic obstructive pulmonary disease (COPD) patients. T helper type 17 (Th17) cells release interleukin (IL)-17 as their effector cytokine under the control of IL-22 and IL-23. Furthermore, Th17 numbers are increased in some chronic inflammatory conditions. To investigate the expression of interleukin (IL)-17A, IL-17F, IL-21, IL-22 and IL-23 and of retinoic orphan receptor RORC2, a marker of Th17 cells, in bronchial biopsies from patients with stable COPD of different severity compared with age-matched control subjects. The expression of IL-17A, IL-17F, IL-21, IL-22, IL-23 and RORC2 was measured in the bronchial mucosa using immunohistochemistry and/or quantitative polymerase chain reaction. The number of IL-22(+) and IL-23(+) immunoreactive cells is increased in the bronchial epithelium of stable COPD compared with control groups. In addition, the number of IL-17A(+) and IL-22(+) immunoreactive cells is increased in the bronchial submucosa of stable COPD compared with control non-smokers. In all smokers, with and without disease, and in patients with COPD alone, the number of IL-22(+) cells correlated significantly with the number of both CD4(+) and CD8(+) cells in the bronchial mucosa. RORC2 mRNA expression in the bronchial mucosa was not significantly different between smokers with normal lung function and COPD. Further, we report that endothelial cells express high levels of IL-17A and IL-22. Increased expression of the Th17-related cytokines IL-17A, IL-22 and IL-23 in COPD patients may reflect their involvement, and that of specific IL-17-producing cells, in driving the chronic inflammation seen in COPD.

Viral infections in exacerbations of asthma and chronic obstructive pulmonary disease.

Respiratory viral infections are recognized as the most frequent cause of asthma and chronic obstructive pulmonary disease (COPD) exacerbations with rhinovirus (i.e. the virus of the common cold) being the most frequent identified virus. The recent development of human experimental models of rhinovirus-induced asthma and COPD exacerbations represent innovative tools with the potential to increase our understanding in this field. Moreover this models will provide the opportunity to test, in a carefully controlled setting, novel pharmacological compounds. In this review we will provide an overview of the role of viral infections in asthma and COPD exacerbations and in particular we will summarize the inflammatory and immunological mechanisms that can pave the way to exacerbation following respiratory viral infection in these patients.

Degree of control of physician-diagnosed asthma and COPD in Italy.

BACKGROUND: It is important for the Italian National Health Service to obtain data on the degree of control of asthma and chronic obstructive pulmonary disease (COPD) in the general population in Italy in order for balanced planning of future investments in these diseases to be made. Currently, precise estimates of these parameters are not available in literature. OBJECTIVES: In collaboration with the Italian Academy of General Practitioners (SIMG; www.simg.it) we have investigated the degree of control of physician-diagnosed asthma and COPD in Italy. METHODS: A standardised questionnaire on asthma and COPD has been self-administered to a sample of 1937 Italian family physicians (representing around 5% of all the Italian doctors involved in general practice) chosen to cover all the Italian counties. RESULTS: We have collected questionnaire data from 19,917 patients with asthma and COPD followed in their practice and 12,438 (62.4%) were correctly filled in enabling evaluation. We selected the number of emergency room visits, hospitalisations and intensive care unit admissions for asthma and COPD in the last 12 months as objective measures of the degree of asthma and COPD morbidity in these patients. The figures were respectively 12.4% (emergency room visits), 17.3% (hospitalisations) and 1.2% (intensive care unit admissions) of all patients with physician-diagnosed asthma and COPD. CONCLUSIONS: This data suggests that in Italy the morbidity of asthma and COPD remains high; representing a significant burden for the Italian National Health Service. There is a clear necessity for further studies to investigate the causes of this incomplete control.

Oxidants in asthma and in chronic obstructive pulmonary disease (COPD).

Experimental and clinical evidences suggest that oxidants play a role in the pathogenesis of respiratory disorders characterised by chronic airway inflammation such as asthma and chronic obstructive pulmonary disease (COPD). The respiratory system is chronically exposed to environmental pollutants, including oxidants. Exogenous sources of oxidants are particularly relevant to the pathogenesis of COPD, being cigarette smoke an extremely rich source of oxidants. In addition, the inflammatory cells recruited to the airways of patients with asthma and COPD, have an exceptional capacity to produce oxidants. Many decades of research have produced a significant amount of data indicating pro-oxidative molecular mechanisms putatively relevant in the pathogenesis of the oxidative stress which characterises these diseases, both locally and systemically. As a consequence, a drug therapy able to restore the redox imbalance in asthma and COPD would probably exert clinical and functional benefits. Indeed, currently available therapies for asthma and COPD can exert an inhibitory effect on oxidant production in the airways. However, it is unknown whether the efficacy of the treatment is somehow linked to the pharmacological modulation of the oxidant/antioxidant balance. So far, it appears that the potential role of antioxidant compounds in the treatment of asthma and COPD has not been fully explored.

Underuse of spirometry by general practitioners for the diagnosis of COPD in Italy.

BACKGROUND: The Global Initiative for Chronic Obstructive Lung Disease (GOLD) underlines that spirometry is the gold standard as the most reproducible, standardised, and objective way of measuring airflow limitation in the diagnosis and assessment of Chronic Obstructive Pulmonary Disease (COPD). However, studies undertaken in different countries have suggested a widespread underuse of spirometry by general practitioners to establish the diagnosis of COPD. Precise estimates of the prevalence of physician-diagnosed COPD in Italy are not currently available. In collaboration with the Italian Academy of General practitioners (SIMG) we have investigated the degree of use of spirometry to establish the diagnosis of COPD in Italy. METHODS: A standardised questionnaire has been self-administered to a sample of 2425 Italian general practitioners (representing 5% of all the Italian doctors involved in general practice). They have been chosen to cover each of the Italian counties. RESULTS: The prevalence of physician-diagnosed COPD was found to be approximately 4%. However, 30% of general practitioners do not use spirometry to establish the diagnosis of COPD. The main reasons given for the failure to use spirometry are (i) that spirometry is not necessary for the diagnosis of COPD or (ii) there are logistical limitations to the access of the patients to lung function laboratories. CONCLUSIONS: This data suggests that contrary to GOLD Guidelines, in Italy, as with other countries, spirometry is not always used in the diagnosis of COPD. There is a clear necessity for further education initiatives targeted to this group of physicians.

Ectopic thymoma simulating a pericardial cyst.

We present a case of a 53 year old man with a thymoma near the pericardium, a rare ectopic localisation of thymoma. A round radiodensity found at the right cardiophrenic angle was initially suspected at the echocardiography to be a pericardial cyst. The diagnosis of thymoma was made only after histopathological examination of the surgically re-sected lesion.

Asthma is not a common cause of severe chronic respiratory failure in non-smokers: ALOT study.

BACKGROUND: Little is known about the long-term natural history of asthma and the long-term clinical and functional consequences in non-smoking patients. From a functional point of view, non-smoking asthmatic patients may have a significantly greater decline in forced expiratory volume in one second (FEV1) compared with non-asthmatic subjects and may develop chronic irreversible (fixed) airflow limitation. This has been related to the physiological consequences of chronic airway inflammation causing airway remodeling. However these lesions are all potentially reversible and there is little radiological evidence indicating lung destruction (pulmonary emphysema), which is potentially irreversible, in non-smoking asthmatics. Severe chronic respiratory failure is the major cause of mortality in patients with severe chronic lung diseases. Domiciliary long-term oxygen therapy (LTOT) is an accepted treatment for patients with severe chronic respiratory failure. Our reasoning, therefore, was that if asthma is a cause of severe chronic respiratory failure in non-smokers we should be able to find non-smoking asthmatics within a large population of patients on LTOT. The aim of our study (Asthma and Long-term Oxygen Therapy, "ALOT") was to investigate the prevalence of non-smoking asthmatics in patients on LTOT in a multi-centre, cross-sectional study. METHODS: Between June and September 2003 we screened all subjects on long-term domiciliary oxygen therapy in three different hospitals in the North-East area of Italy (within the provinces of Ferrara and Bologna). Taken collectively, we have found one-hundred and eighty-four patients on LTOT. We have reviewed their clinical data (age, sex, smoking, history and physical examination, arterial blood gas analysis, pulmonary function). RESULTS: 114 patients (all smokers) fulfilled the diagnostic criteria for COPD. Seventy patients (all smokers) had other diseases. We were unable to find any non-smokers in our screened population of subjects on long-term domiciliary oxygen therapy. Furthermore, there was no past history of asthma and/or acute wheezing episodes in either of the patient groups. CONCLUSIONS: This data suggests that asthma is an uncommon cause of severe chronic respiratory failure necessitating long-term domiciliary oxygen therapy in non-smokers and supports the current consensus that asthma and COPD are different diseases with differing stages of severity and the concept that long-term avoidance of active smoking is fundamental for the prevention of severe chronic respiratory failure.

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.

Effect of cigarette smoking on haem-oxygenase expression in alveolar macrophages.

We investigated the effect of chronic cigarette smoking on the expression of haem-oxygenase (HO)-1 and HO-2. Normal subjects and asymptomatic young current smokers with normal lung function tests underwent bronchoalveolar lavage for recovery of macrophages. Reverse transcription/polymerase chain reaction (RT-PCR) analysis showed no significant difference in HO-1 and HO-2 mRNA expression between the two groups. On the other hand, Western blot analysis showed a significant (P<0.05) reduction of HO-2 protein, but not of HO-1, in alveolar macrophages from smokers compared to normal. There was no significant differences by immunocytochemistry for HO-1 and HO-2 expression between the groups. We concluded that HO-2 expression is reduced in alveolar macrophages of smokers, possibly due to the oxidative stress of cigarette smoke. This may in turn lead to reduced protection against further oxidative insults.

Birbeck granules: contribution to the comprehension of intracytoplasmic evolution.

We investigated the ultrastructure of Birbeck granules which are found in some malignant histiocytoses such as histiocytosis X, Letterer-Siwe disease, Hand-Schüller-Christian disease, eosinophilic granuloma of the bone and self-healing reticulohistiocytosis. The research is based on the systemic study of Birbeck granules, from their formation to intracytoplasmic development, examining with the electron microscope at regular intervals ultrathin sections derived from biopsies of two cases of Langerhans cell histiocytosis.

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.

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.