Bronchial remodeling, including increased bronchial smooth muscle (BSM) mass, contributes to bronchial obstruction in asthma. However, its mechanisms are complex and remain controversial. Recently, a ...role of the chitinase 3-like 1 protein (YKL-40) has been evoked in asthma. Indeed, YKL-40 concentration was increased in asthmatic serum, and correlated with asthma severity and subepithelial membrane thickness. Nevertheless, the role of YKL-40 on BSM cells remains to be investigated.
To evaluate whether YKL-40 altered the physiologic properties of BSM cells in asthma in vitro and ex vivo.
We enrolled 40 subjects with asthma, 13 nonsmokers, and 16 smokers. BSM cells were derived from bronchial specimens obtained by either fiberoptic bronchoscopy or lobectomy. We assessed cell proliferation using BrdU, flow cytometry, and cell count; signaling intermediates using Western blot; cell migration using inserts, wound healing, and phalloidin staining; and cell synthesis using ELISA and Western blot. The involvement of protease activated receptor (PAR)-2 was evaluated using blocking antibody and dedicated lentiviral small hairpin RNA. We also determined the BSM area and the YKL-40 staining ex vivo using immunohistochemistry on biopsies from subjects with asthma and control subjects.
We demonstrated that YKL-40 increased BSM cell proliferation and migration through PAR-2-, AKT-, ERK-, and p38-dependent mechanisms. The increased cell migration was higher in BSM cells of subjects with asthma than that of control subjects. Furthermore, YKL-40 epithelial expression was positively correlated with BSM mass in asthma.
This study indicates that YKL-40 promotes BSM cell proliferation and migration through a PAR-2-dependent mechanism.
Chronic obstructive pulmonary disease (COPD) is an important cause of morbidity and mortality around the world. The aim of our study was to determine the association between specific comorbidities ...and COPD severity.
Pulmonologists included patients with COPD using a web-site questionnaire. Diagnosis of COPD was made using spirometry post-bronchodilator FEV1/FVC < 70%. The questionnaire included the following domains: demographic criteria, clinical symptoms, functional tests, comorbidities and therapeutic management. COPD severity was classified according to GOLD 2011. First we performed a principal component analysis and a non-hierarchical cluster analysis to describe the cluster of comorbidities.
One thousand, five hundred and eighty-four patients were included in the cohort during the first 2 years. The distribution of COPD severity was: 27.4% in group A, 24.7% in group B, 11.2% in group C, and 36.6% in group D. The mean age was 66.5 (sd: 11), with 35% of women. Management of COPD differed according to the comorbidities, with the same level of severity. Only 28.4% of patients had no comorbidities associated with COPD. The proportion of patients with two comorbidities was significantly higher (p < 0.001) in GOLD B (50.4%) and D patients (53.1%) than in GOLD A (35.4%) and GOLD C ones (34.3%). The cluster analysis showed five phenotypes of comorbidities: cluster 1 included cardiac profile; cluster 2 included less comorbidities; cluster 3 included metabolic syndrome, apnea and anxiety-depression; cluster 4 included denutrition and osteoporosis and cluster 5 included bronchiectasis. The clusters were mostly significantly associated with symptomatic patients i.e. GOLD B and GOLD D.
This study in a large real-life cohort shows that multimorbidity is common in patients with COPD.
Background Chronic obstructive pulmonary disease (COPD) is characterized by peribronchial fibrosis. The chronic course of COPD is worsened by recurrent acute exacerbations. Objective The aim of the ...study was to evaluate the recruitment of blood fibrocytes in patients with COPD during exacerbations and, subsequently, to identify potential mechanisms implicated in such recruitment. Methods Using flow cytometry, we quantified circulating fibrocytes and characterized their chemokine receptor expression in 54 patients with COPD examined during an acute exacerbation (V1) and 2 months afterward (V2) and in 40 control subjects. The role of the chemokines CXCL12 and CCL11 in fibrocyte migration was investigated by using a chemotaxis assay. Patients were followed for up to 3 years after V1. Results We demonstrated a significantly increased number of circulating fibrocytes at V1 compared with control subjects. The number of circulating fibrocytes decreased at V2. A high percentage of circulating fibrocytes during exacerbation was associated with increased risk of death. The percentage of fibrocytes at V2 was negatively correlated with FEV1 , forced vital capacity, FEV1 /forced vital capacity ratio, transfer lung capacity of carbon monoxide, and Pa o2 . Fibrocytes highly expressed CXCR4 and CCR3, the chemokine receptors for CXCL12 and CCL11, respectively. Fibrocytes collected from patients with COPD at V1 had increased chemotactic migration in response to CXCL12 but not to CCL11 compared with those from control subjects. Plerixafor, a CXCR4 antagonist, decreased fibrocyte migration to plasma from patients with exacerbating COPD. Conclusion Blood fibrocytes are recruited during COPD exacerbations and related to mortality and low lung function. The CXCL12/CXCR4 axis is involved in such fibrocyte recruitment (Firebrob study; ClinicalTrials NCT01196832 ).
The purposes of this study were to compare airway wall attenuation in subjects with asthma and subjects without asthma; to correlate this value with pulmonary function test results, standard ...bronchial CT parameters, and immunohistologic data; and to identify CT parameters that influence obstructive indexes.
Bronchial airway wall attenuation was averaged over four bronchi in 27 subjects with asthma and 15 control subjects without asthma. The following five standard bronchial parameters also were assessed: lumen area, wall area, wall thickness, wall-to-lumen area ratio, and wall-to-total area ratio (wall area percentage). These parameters were compared between groups and correlated with functional data. Ability to predict patient group with these parameters was determined by comparison of receiver operating characteristic curves and areas under the curve. The influence of the parameters on obstructive indexes was assessed by multivariate analysis. Correlations between wall attenuation value and histologic data were studied in 11 patients with asthma.
Wall attenuation value was greater in patients with asthma (-322 ± 79 HU) than in control subjects (-463 ± 69 HU). Correlation coefficients of wall attenuation value with functional obstructive parameters were significant and greater than those obtained for any other CT parameter. The area under the curve of wall attenuation value was greater than that of bronchial lumen area and bronchial wall area. In the model of multiple regression that included wall attenuation value and wall-to-total area ratio, wall attenuation value was the only measurement that significantly influenced obstructive indexes (R(2) = 0.39-0.43). Wall attenuation value correlated with mast cell infiltration.
Compared with the usual bronchial CT parameters, airway wall attenuation better differentiates patients with asthma from control subjects and better correlates with obstruction.
Background Increase of bronchial smooth muscle (BSM) mass is a crucial feature of asthma remodeling. The mechanisms of such an increased BSM mass are complex but involve enhanced mitochondrial ...biogenesis, leading to increased proliferation of BSM cells in asthmatic patients. The major tumor suppressor protein p53 is a key cell regulator involved in cell proliferation and has also been implicated in mitochondrial biogenesis. However, the role of p53 in BSM cell proliferation and mitochondrial biogenesis has not been investigated thus far. Objective We sought to evaluate the role of p53 in proliferation of BSM cells in asthmatic patients and mitochondrial biogenesis. Methods The expression of p53 was assessed both in vitro by using flow cytometry and Western blotting and ex vivo by using RT-PCR after laser microdissection. The role of p53 was assessed with small hairpin RNA lentivirus in both asthmatic patients and control subjects with BSM cell proliferation by using 5-bromo-2′-deoxyuridine and cell counting and in the expression of p21, BCL2-associated X protein, mitochondrial transcription factor A (TFAM), and peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α). Results Twenty-nine patients with moderate-to-severe asthma and 26 control subjects were enrolled in the study. p53 expression was increased in BSM from asthmatic patients both ex vivo and in vitro , with a decreased interaction with mouse double minute 2 homolog (Mdm2) and an increased phosphorylation of serine 20. p53 did not inhibit the transcription of both TFAM and PGC-1α in BSM cells from asthmatic patients. As a consequence, p53 is unable to slow the increased mitochondrial biogenesis and hence the subsequent increased proliferation of BSM cells in asthmatic patients. Conclusion this study suggests that p53 might act as a new potential therapeutic target against BSM remodeling in asthmatic patients.
Airway remodeling is a major pathological feature of asthma. Up to now, its quantification still requires invasive methods. In this study, we aimed at determining whether in vivo micro-computed ...tomography (micro-CT) is able to demonstrate allergen-induced airway remodeling in a flexible mouse model of asthma. Sixty Balb/c mice were challenged intranasally with ovalbumin or saline at 3 different endpoints (Days 35, 75, and 110). All mice underwent plethysmography at baseline and just prior to respiratory-gated micro-CT. Mice were then sacrificed to assess bronchoalveolar lavage and lung histology. From micro-CT images (voxel size = 46×46×46 µm), the numerical values of total lung attenuation, peribronchial attenuation (PBA), and PBA normalized by total lung attenuation were extracted. Each parameter was compared between OVA and control mice and correlation coefficients were calculated between micro-CT and histological data. As compared to control animals, ovalbumin-sensitized mice exhibited inflammation alone (Day 35), remodeling alone (Day 110) or both inflammation and remodeling (Day 75). Normalized PBA was significantly greater in mice exhibiting bronchial remodeling either alone or in combination with inflammation. Normalized PBA correlated with various remodeling markers such as bronchial smooth muscle size or peribronchial fibrosis. These findings suggest that micro-CT may help monitor remodeling non-invasively in asthmatic mice when testing new drugs targeting airway remodeling in pre-clinical studies.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Asthmatic bronchial smooth muscle (BSM) is characterized by structural remodeling associated with mast cell infiltration displaying features of chronic degranulation. Mast cell-derived tryptase can ...activate protease activated receptor type-2 (PAR-2) of BSM cells. The aims of the present study were (i) to evaluate the expression of PAR-2 in both asthmatic and non asthmatic BSM cells and, (ii) to analyze the effect of prolonged stimulation of PAR-2 in asthmatic BSM cells on cell signaling and proliferation. BSM cells were obtained from both 33 control subjects and 22 asthmatic patients. PAR-2 expression was assessed by flow cytometry, western blot and quantitative RT-PCR. Calcium response, transduction pathways and proliferation were evaluated before and following PAR-2 stimulation by SLIGKV-NH2 or trypsin for 1 to 3 days. Asthmatic BSM cells expressed higher basal levels of functional PAR-2 compared to controls in terms of mRNA, protein expression and calcium response. When PAR-2 expression was increased by means of lentivirus in control BSM cells to a level similar to that of asthmatic cells, PAR-2-induced calcium response was then similar in both types of cell. However, repeated PAR-2 stimulations increased the proliferation of asthmatic BSM cells but not that of control BSM cells even following lentiviral over-expression of PAR-2. Such an increased proliferation was related to an increased phosphorylation of ERK in asthmatic BSM cells. In conclusion, we have demonstrated that asthmatic BSM cells express increased baseline levels of functional PAR-2. This higher basal level of PAR-2 accounts for the increased calcium response to PAR-2 stimulation, whereas the increased proliferation to repeated PAR-2 stimulation is related to increased ERK phosphorylation.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The aim of our study was to evaluate the feasibility of non-invasive respiratory-gated micro-computed tomography (micro-CT) for assessment of airway remodelling in a mouse asthma model. Six female ...BALB/c mice were challenged intranasally with ovalbumin. A control group of six mice received saline inhalation. All mice underwent plethysmographic study and micro-CT. For each mouse, peribronchial attenuation values of 12 bronchi were measured, from which a peribronchial density index (PBDI) was computed. Mice were then sacrificed and lungs examined histologically. Final analysis involved 10 out of 12 mice. Agreement of measurements across observers and over time was very good (intraclass correlation coefficients: 0.94–0.98). There was a significant difference in PBDI between asthmatic and control mice (−210 vs. −338.9 HU,
P
= 0.008). PBDI values were correlated to bronchial muscle area (
r
= 0.72,
P
= 0.018). This study shows that respiratory-gated micro-CT may allow non-invasive monitoring of bronchial remodelling in asthmatic mice and evaluation of innovative treatment effects.
Summary Background Fractional exhaled nitric oxide (FE NO) is a marker of airway inflammation in asthma. Monitoring of such inflammation is currently not included in asthma guidelines and remains ...controversial. The hypothesis underlying the present study was that, FE NO could help assessing asthma control and, therefore, improve its management, by predicting loss of control in asthmatics. Methods A total of 90 adult asthmatics were included in the study. Asthma control was evaluated according to ACQ. All patients underwent FE NO by chemiluminescent (EndoNO) and hand-held (MINO) devices, followed by lung function testing. Results MINO was accurate as compared to EndoNO. FE NO was significantly increased in uncontrolled as compared to controlled asthmatics using both devices. FE NO measurement was able to predict control maintenance in controlled asthmatics in the absence of any change in their treatment. Indeed, using cut-off values of 31 and 40 ppb, the negative predictive values were 95 and 97% for EndoNO and MINO, respectively. EndoNO and MINO were also able to assess asthma control, although to a lesser extent. Conclusions These findings suggest that FE NO can predict the persistence of asthma control in controlled patients and may now be used in asthma management since it can accurately be measured by means of hand-held devices.
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