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Biomedical subjects

Pascal Chanez

Publications and source records attributed to Pascal Chanez.

16 recordsLinked to original sources
PubMed2007

Air trapping in mild and moderate asthma: effect of inhaled corticosteroids.

BACKGROUND: Air trapping reflects small airway obstruction in asthma and can be assessed quantitatively by high-resolution computed tomography (HRCT). Hydrofluoroalkane-beclomethasone dipropionate (HFA-BDP) is deposited across all sizes of airways, including the small ones. However, its long-term effect on air trapping remains unknown in uncontrolled asthma. OBJECTIVES: To compare the effect of inhaled corticosteroids of different particle size - HFA-BDP and fluticasone propionate (FP) - on lung attenuation in mild-to-moderate uncontrolled asthma. METHODS: A randomized study was performed to analyze the effect of HFA-BDP (400 microg/d) or FP (500 microg/d) given over a period of 3 months to patients with uncontrolled mild-to-moderate asthma. HRCT was performed with spirometric gating, and lung attenuation was measured at residual volume and at pulmonary total capacity. The difference between inspiratory and expiratory attenuation was calculated as an air trapping index. RESULTS: Twenty-five out of 58 patients had abnormal air trapping and could be included in the study. Lung attenuation significantly diminished in the posterior zones of the lung after a 3-month treatment with HFA-BDP or FP, but the difference between the groups was not significant. Adjusted mean variations of the air trapping index from baseline to treatment completion were 34.3 (11.2, 57.3) and 27.3 (6.4, 48.2) for the HFA-BDP and FP groups, respectively. However, the reduction of air trapping area was more pronounced in the group treated with HFA-BDP. CONCLUSION: Inhaled corticosteroids decrease air trapping in uncontrolled asthma regardless of their particle size. CLINICAL IMPLICATIONS: In mild-to-moderate asthma, air trapping assessed by HRCT may be a new outcome related to the control of the disease.

Administration, Inhalation↗
PubMed2006

Safety, tolerability and efficacy of indacaterol, a novel once-daily beta(2)-agonist, in patients with COPD: a 28-day randomised, placebo controlled clinical trial.

In patients with chronic obstructive pulmonary disease (COPD) classified as moderate onwards, Global Initiative for Chronic Obstructive Lung Disease (GOLD) Guidelines recommend regular treatment with one or more long-acting bronchodilators, such as beta(2)-agonists or anticholinergics. In contrast to currently available long-acting beta(2)-agonists, which have a duration of action of 12 h, indacaterol has demonstrated effective 24-h bronchodilation on once-daily dosing. A double-blind, randomised, placebo-controlled study was conducted to compare the safety, tolerability and efficacy of indacaterol with that of placebo, over a 28-day period, in patients with moderate COPD (as defined by GOLD 2001 criteria; equivalent to moderate-to-severe COPD in the GOLD 2005 criteria). Patients were randomised 2:2:1 to receive indacaterol 400 microg or 800 microg or placebo once-daily (between 07:00 and 11:00 h) via a single-dose dry-powder inhaler for 28 days. Assessments included monitoring of adverse events (AEs), blood chemistry (including serum potassium and blood glucose), vital signs (blood pressure and heart rate), electrocardiograms and spirometry. One hundred and sixty-three patients were randomised, with 155 (95%) completing the study. There were no statistically significant differences between treatment groups in the overall incidence of AEs, with AEs reported by 35%, 51% and 25% of patients in the indacaterol 400 microg, 800 microg and placebo groups, respectively. The majority of AEs were mild or moderate in severity, and there were no study-drug related serious AEs. There were no statistically significant differences between indacaterol groups and placebo in mean pulse rate and QTc interval, and isolated statistically significant (p<0.05) treatment-placebo differences in mean blood pressure, blood glucose and serum potassium. There was a statistically significant improvement in FEV(1) vs placebo at all post-baseline timepoints for both indacaterol treatment groups; 30 min post-dose, adjusted mean+/-SE FEV(1) indacaterol-placebo differences were: Day 1, 220+/-36 ml and 210+/-36 ml; Day 14, 320+/-50 ml and 270+/-50 ml; Day 28, 260+/-61 ml and 200+/-61 ml for 400 and 800 microg, respectively (all p<0.01 vs placebo). Bronchodilation was still apparent after 24h, with pre-dose (i.e. trough) adjusted mean+/-SE FEV(1) indacaterol-placebo differences of: Day 14, 230+/-44 ml and 210+/-44 ml; Day 28, 220+/-49 ml and 210+/-49 ml for indacaterol 400 and 800 microg, respectively (all p<0.0001 vs placebo). Once-daily indacaterol was well tolerated at doses up to 800 microg with a good overall safety profile. There was no statistical difference at any dose between the safety of indacaterol and placebo. Furthermore, this study supports the previously demonstrated 24-h bronchodilator efficacy of indacaterol.

Administration, Inhalation↗
PubMed2006

Interference of psychological factors in difficult-to-control asthma.

BACKGROUND: Most patients with asthma can be controlled with suitable medication, but 5-10% of them remain difficult to control despite optimal management. OBJECTIVE: We investigated whether patients with difficult-to-control asthma (DCA) or controlled asthma (CA) differ with respect to psychological factors, such as general control beliefs on life events. METHODS: DCA was defined as an absence of control despite optimal management. Recent control was measured using the Asthma Control Questionnaire. General control beliefs were investigated using a Locus of Control scale (LOC). RESULTS: Patients with DCA had a significantly higher external LOC as compared to patients with CA (P=0.01). In the DCA group, the hospital admission rate was highly significant in association with the external LOC (P=0.004) as compared to the internal LOC trend. CONCLUSION: This study showed that patients with DCA had different general control beliefs which might have hampered their management and interfered with their therapeutic adherence. The present findings could enhance management of DCA in a clinical setting.

Adult↗
PubMed2006

Enhanced frequency of CD18- and CD49b-expressing T cells in peripheral blood of asthmatic patients correlates with disease severity.

BACKGROUND: Results from a transcriptome analysis of human CD4+ T regulatory type 1 (Tr1) clones have indicated that transcripts for the integrins CD18 and CD49b are overexpressed in these cells. The aim of this study was to investigate whether the presence of T cells concomitantly expressing these molecules could be detected in asthmatic patients and represent Tr1 cells. METHODS: Expression of CD18 and CD49b was analyzed by flow cytometry on peripheral blood mononuclear cells from asthmatic patients of various severity and healthy subjects. The cytokine production profile of purified CD4+ CD18(high) CD49b+ T cells was analyzed by ELISA. The effect of glucocorticoid treatment on the expression of CD18 and CD49b was determined. RESULTS: The frequency of peripheral blood CD18(high) CD49b+ T cells was significantly elevated in severe asthmatic patients, as compared with both mild asthmatic and healthy donors, and was diminished in asthmatic patients with a controlled status of the disease. Neither short-course oral glucocorticoid treatment of asthmatic patients ex vivo, nor culture of their peripheral blood mononuclear cells with dexamethasone in vitro, increased the frequency of CD18(high) CD49b+ T cells, indicating that their presence seems to be independent from recent anti-inflammatory treatment. However, purified CD4+ CD18(high) CD49b+ T cells from these patients, in contrast to those from healthy donors, lacked the production of the immunosuppressive cytokine interleukin-10. CONCLUSION: In contrast to healthy donors, peripheral blood CD18(high) CD49b+ T cells of asthmatic patients do not fulfill the phenotypic criteria of Tr1 cells. Nevertheless, the presence of elevated numbers of peripheral blood CD18(high) CD49b+ T cells is characteristic for patients with severe and uncontrolled asthma.

Adult↗
PubMed2006

[Difficult asthma].

Difficult asthma is a major issue in pulmonary medicine today because of its cost for patients and society. Difficult asthma is asthma that remains uncontrolled despite optimal specialist management. The validity of the diagnosis must be reconsidered in these cases: associated or differential diagnoses may be involved in the lack of control, and it is always necessary to assess the patient's treatment adhesion. Sufficient time--at least a year--must be taken to get to know the patient and to meet the objectives set. The standard asthma therapies should be tested objectively. Severe asthma is the reality of difficult asthma that endures despite a reaffirmed diagnosis, optimal compliance and controlled comorbidities. Better knowledge is needed of the pathophysiology of these patients' asthma. Improved knowledge of these phenotypes will make it possible to develop innovative treatments. They will need to be validated in clinical research for subsequent use that is wider but more rational because targeted at phenotypes likely to benefit from them.

Administration, Oral↗
PubMed2005

Severe asthma is associated with a loss of LX4, an endogenous anti-inflammatory compound.

BACKGROUND: Lipoxins and 15-epi-lipoxins are lipid mediators that modulate leukocyte trafficking and promote the inflammation resolution. They are produced by different enzymatic pathways. Patients with severe asthma present ongoing airway inflammation despite chronic long-term treatment including oral glucocorticoids. OBJECTIVES: The aim of this study was to assess the presence of proinflammatory and anti-inflammatory mediators in the supernatants of induced sputum. METHODS: Induced sputum supernatants were collected from 10 normal subjects; 12 subjects with mild, 15 with moderate, and 24 with severe asthma; and 13 patients with chronic obstructive pulmonary disease. First, we validated the measurements of IL-8, leukotriene B 4 , lipoxin A 4 , and 15-epi-lipoxin A 4 in these samples. Then we measured these mediators by using immunoenzymatic methods. RESULTS: IL-8 levels were highly increased in patients with severe asthma ( P < .0001), and leukotriene B 4 levels were significantly increased in patients with severe asthma and patients with chronic obstructive pulmonary disease. Lipoxin A 4 was significantly increased in the supernatant obtained from patients with mild asthma ( P < .0001), whereas 15-epi-lipoxin A 4 levels were higher in patients with severe asthma ( P = .05). More interestingly, we found a positive correlation between the level of lipoxin A 4 and IL-8 in patients with mild asthma. CONCLUSION: These results indicate that induced sputum is a suitable method to assess lipoxin and 15-epi-lipoxin measurements in bronchi. The mechanisms involved in the synthesis of these 2 eicosanoid mediators would be helpful to understand better the imbalance between proinflammatory and anti-inflammatory mediators occurring in severe asthma. Lipoxin production involves interaction between lipoxygenases, whereas 15-epi-lipoxin production might involve CytP450 activity.

Adult↗
PubMed2004

[The measurement of exhaled nitric oxide, a new tool in the management of asthma?].

A GOOD DIAGNOSTIC TEST FOR ASTHMA: Chronic airway inflammation, main feature of asthma, can be assessed by measuring the exhaled nitric oxide (NO) level. Measurement of NO is standardized, non-invasive and easy to use in both children and adults. Studies have shown that it is a good diagnostic test for asthma when NO is high. However, other conditions or pathologies must be searched for because they may influence the results. ITS PLACE IN TREATMENT: Although exhaled NO helps to characterise the patients with asthma, other studies are required to show that it can help to improve the follow-up of such patients. Nevertheless, this tool has not yet been validated in the daily treatment of asthma and further research is still ongoing.

Adult↗
PubMed2004

Effects of inhaled corticosteroids on pathology in asthma and chronic obstructive pulmonary disease.

The effects of inhaled corticosteroids (ICSs) have been investigated in asthma and chronic obstructive pulmonary disease (COPD) using endobronchial biopsies. In asthma, most studies have shown reductions in infiltrating eosinophils, mast cells, and T lymphocytes. Cell-associated mediators, such as cytokines derived from type 2 T-helper lymphocytes, are decreased as assessed by immunostaining and molecular biology techniques. More recently, attention has been devoted to the effect of ICSs on structural changes. In asthma, ICSs have been shown in some studies to affect collagen deposition (size of the reticular basement membrane), the number of vessels, or epithelial integrity. The correlations between those findings and various clinical and functional outcomes are far from clear. A long-term study has shown a decrease in the basement membrane size in a group of patients with asthma treated according to their level of airway hyperreactivity. In COPD, ICSs generally do not decrease neutrophils, macrophages, and CD8(+) T lymphocytes. The effects of these drugs on structural changes in COPD have not been investigated extensively. Long-term prospective studies are needed to demonstrate the potential for ICSs to affect the natural history of chronic bronchial diseases.

Administration, Inhalation↗
PubMed2003

Persistent activation of nuclear factor-kappaB signaling pathway in severe uncontrolled asthma.

The transcription factor nuclear factor-kappaB (NF-kappaB) is inactive when bound to its inhibitory protein IkappaBalpha. On cell stimulation with inflammatory signals, IkappaBalpha is phosphorylated by IkappaB kinases and subsequently degraded. Freed NF-kappaB then induces expression of cytokines such as granulocyte-macrophage colony-stimulating factor, interleukin-8, and regulated upon activation, normal T cell expressed and secreted. These mediators are overexpressed in asthma and are downregulated by glucocorticoids through NF-kappaB activity repression. However, high levels of granulocyte-macrophage colony-stimulating factor, interleukin-8, and regulated upon activation, normal T cell expressed and presumably secreted are released by peripheral blood mononuclear cells isolated from patients with severe asthma despite continuous systemic glucocorticoid treatment. We report that these mediators are markedly decreased by pyrrolidinedithiocarbamate, an inhibitor of NF-kappaB activation. To further characterize the persistent NF-kappaB activation in severe asthma, we analyzed the expression of various components of this activation pathway in healthy subjects and in asthmatics with mild controlled, and moderate and severe uncontrolled disease. We found high amounts of phosphorylated IkappaBalpha characterizing the three asthmatic groups. Western blot analyses indicated that in peripheral blood mononuclear cells the IkappaB kinase beta and p65 levels were greater in moderate and severe asthmatics than in normal subjects. Electrophoretic mobility shift assay and immunocytochemistry showed a greater activation status of p65 in severe asthmatics. Our data suggest that exaggerated NF-kappaB activation perpetuates inflammatory mediators production in severe asthma.

Adult↗
PubMed2003

High levels of urinary leukotriene E4 excretion in steroid treated patients with severe asthma.

Urinary LTE4 reflects the whole body production of the cysteinyl-leukotrienes (LTC4, LTD4 and LTE4) that are established mediators in asthma. The influence of chronic inhaled and oral glucocorticoid treatment on urinary excretion of leukotriene (LT) E4 was investigated in subjects with asthma. Enzyme immunoassay analysis of LTE4 was performed in spot urine samples collected from 40 patients with severe asthma, 25 patients with mild-moderate asthma and 20 non-asthmatic control subjects. Urinary LTE4 was significantly higher in patients with severe asthma (69.7 +/- 5.5) as compared to mild-moderate asthma (45.7 +/- 3.3 with P < 0.0004) and control (42.5 +/- 2.5 with P < 0.0001). Despite chronic systemic treatment with glucocorticoids, chronically severe asthma had presented with higher levels of LTE4 compared to mild moderate asthma and healthy controls. The findings support previous indications that one important component in asthmatic airway inflammation, the cysteinyl-leukotriene pathway remains relatively unopposed by oral glucocorticoids.

Administration, Oral↗
PubMed2002

Lipoxin A4 stimulates a cytosolic Ca2+ increase in human bronchial epithelium.

Lipoxins are biologically active eicosanoids possessing anti-inflammatory properties. Using a calcium imaging system we investigated the effect of lipoxin A(4) (LXA(4)) on intracellular [Ca(2+)] ([Ca(2+)](i)) of human bronchial epithelial cell. Exposure of the cells to LXA(4) produced a dose-dependent increase in [Ca(2+)](i) followed by a recovery to basal values in primary culture and in 16HBE14o(-) cells. The LXA(4)-induced [Ca(2+)](i) increase was completely abolished after pre-treatment of the 16HBE14o(-) cells with pertussis toxin (G-protein inhibitor). The [Ca(2+)](i) response was not affected by the removal of external [Ca(2+)] but completely inhibited by thapsigargin (Ca(2+)-ATPase inhibitor) treatment. Pre-treatment of the bronchial epithelial cells with either MDL hydrochloride (adenylate cyclase inhibitor) or (R(p))-cAMP (cAMP-dependent protein kinase inhibitor) inhibited the Ca(2+) response to LXA(4). However, the response was not affected by chelerytrine chloride (protein kinase C inhibitor) or montelukast (cysteinyl leukotriene receptor antagonist). The LXA(4) receptor mRNA was detected, by RT-PCR, in primary culture of human bronchial epithelium and in immortalized 16HBE14o(-) cells. The functional consequences of the effect of LXA(4) on intracellular [Ca(2+)](i) have been investigated on Cl(-) secretion, measured using the short-circuit techniques on 16HBE14o(-) monolayers grown on permeable filters. LXA(4) produced a sustained stimulation of the Cl(-) secretion by 16HBE14o(-) monolayers, which was inhibited by BAPTA-AM, a chelator of intracellular calcium. Taken together our results provided evidence for the stimulation of a [Ca(2+)](i) increase by LXA(4) through a mechanism involving its specific receptor and protein kinase A activation and resulting in a subsequent Ca(2+)-dependent Cl(-) secretion by human airway epithelial cells.

Acetates↗
PubMed2002

Lipoxins are potential endogenous antiinflammatory mediators in asthma.

Lipoxins, endogenous eicosanoids biosynthetized in vivo at inflammation sites, are potential antiinflammatory mediators. Subjects with severe asthma present chronic inflammation of the airways despite long-term treatment with oral glucocorticoids. Therefore it is of interest to investigate the potential antiinflammatory effects of lipoxin A4 (LXA4) and lipoxin B4 (LXB4) that could attenuate chronic inflammation. In a first time, we detected interleukin (IL)-8 and LXA4 in supernatants of induced sputum. IL-8 was heightened in severe asthma (p = 0.001), whereas high concentrations of lipoxin A4 were present in mild asthma (p = 0.001). We then studied the effects of LXA4 on IL-8 released in vitro. Nanomolar concentrations of LXA4 and LXB4 inhibited the IL-8 released by peripheral blood mononuclear cells from the two groups of patients with asthma: a maximal inhibition of 29.4% (p < 0.01) was observed for patients with mild asthma, and 41.5% inhibition (p < 0.001) for patients with severe asthma at 1 nM and 100 nM LXA4 concentrations, respectively. Polymerase chain reaction analysis indicated that peripheral blood mononuclear cells from patients with asthma expressed the LXA4 receptor mRNA. Moreover, pertussis toxin reversed LXA4- and LXB4-inhibited IL-8 release. These findings suggest that lipoxins have potential antiinflammatory action in asthma.

Asthma↗
PubMed2002

Modulation of cadherin and catenins expression by tumor necrosis factor-alpha and dexamethasone in human bronchial epithelial cells.

Asthma is an inflammatory disease, and the epithelial mesenchymal unit appears to be of importance in regulating the disease mechanisms. Cell-cell adhesion plays an important role in tissue morphogenesis and homeostasis and is commonly mediated by cadherins, a family of Ca(2+)-dependent transmembrane adhesion receptors. The cadherin family is involved in control of the cellular architecture. Proinflammatory cytokines such as tumor necrosis factor (TNF)-alpha are involved in asthma and may interfere with epithelial integrity. In the present study, we investigated the role of TNF-alpha and dexamethasone on the expression of E-cadherin, beta-catenin, and gamma-catenin. We used two bronchial epithelial cell models: primary small airway epithelial cell cultures and primary culture obtained from human bronchial tubes. After 48 h of TNF-alpha stimulation with or without dexamethasone expression of E-cadherin, beta-catenin and gamma-catenin were analyzed using Western blot analysis and immunofluorescence. This study showed a decrease in the expression of adhesion molecules in both epithelial cell cultures after stimulation. Dexamethasone and anti-TNF-alpha inhibited this effect. In unstimulated cells, E-cadherin and beta- and gamma-catenin expression was membranous, expressed only on the lateral cell wall with minimal cytoplasmic expression. Immunoreactivity was cytoplasmic in stimulated cells. We demonstrated, using Western blot analysis and immunofluorescence, that proinflammatory cytokines could be responsible for structural damage to the epithelium and that this process was potentially reversed by steroids.

Anti-Inflammatory Agents↗