Airway Remodeling In Asthmatic Patients Research Articles

The Role of Vitamin D Supplementation on Airway Remodeling in Asthma: A Systematic Review.

Asthma is a common chronic respiratory disease that affects millions of people worldwide, and its prevalence continues to increase. Vitamin D has been proposed as a potential environmental factor in asthma pathogenesis, due to its immunomodulatory effects. This systematic review aimed to evaluate the effect of vitamin D supplementation in order to prevent airway remodeling in asthmatic patients. Four electronic databases, namely PubMed, Embase, Clinical trails.gov, and CINAHL, were thoroughly searched to conduct a comprehensive literature review. The International Prospective Register of Systematic Reviews (CRD42023413798) contains a record of the registered protocol. We identified 9447 studies during the initial search; 9 studies (0.1%) met the inclusion criteria and were included in the systematic review. All included studies were experimental studies that investigated the impact of vitamin D supplementation on airway remodeling in asthma. The studies included in this review suggest that vitamin D inhibits airway smooth muscle cell contraction and remodeling, reduces inflammation, regulates collagen synthesis in the airways, and modulates the action of bronchial fibroblasts. However, one study suggests that TGF-β1 can impair vitamin D-induced and constitutive airway epithelial host defense mechanisms. Overall, vitamin D appears to have a potential role in the prevention and management of asthma.

Research advances in airway remodeling in asthma: a narrative review.

Background and ObjectiveAsthma is a common chronic disorder of the airway, and its disability and mortality rates continue to increase each year. Due to the lack of an ideal treatment, asthma control in China remains unsatisfactory. Airway remodeling is the pathological basis for the eventual development of the fixed airflow limitation in asthmatic patients. Early diagnosis and the prevention of airway remodeling has the potential to decrease disease severity, to improve control, and to prevent disease expression.MethodsThis article presents an overview. The literature was combed through via CNKi and PubMed according to the listed keywords. We considered Chinese and English original publications (basic science and clinical), reviews and abstracts of 21th Century.Key Content and FindingsWe review the pathological features and pathogenesis of, and the interventional treatment options for airway remodeling in asthmatic patients, emphasizing the importance of airway remodeling in asthma and providing novel insights into the prevention and control of asthma.ConclusionsThus, there have been research advances in airway remodeling, especially in the areas of slowing down or reversing airway remodeling. As growing studies showed, treating airway remodeling is a promising strategy in preventing the occurrence and progression of asthma. Breakthroughs in these difficulties airway remodeling still facing will open up new avenues in the research and treatment of asthma.

AEROBIC TRAINING MODULATE PULMONARY AND SYSTEMIC INFLAMMATORY AND FIBROTIC RESPONSE IN PATIENTS WITH ASTHMA

TOPIC: Pulmonary Rehabilitation TYPE: Original Investigations PURPOSE: Airway remodeling is a hallmark of asthma, characterized by structural changes in the airways, including epithelial metaplasia, subepithelial fibrosis, angiogenesis and thickening of smooth muscle. Airway remodeling promotes irreversible loss of lung function and subside the airway hyperresponsiveness and is associated with severity of the disease. In addition, airway remodeling is caused by an unresolved chronic inflammatory response, involving exacerbated release of profibrotic mediators. Aerobic exercise (AE) is the main component of pulmonary rehabilitation and in pre-clinical studies in models of asthma, AE reduced airway remodeling, by reducing the release of pro-fibrotic mediators and increasing the release of anti-fibrotic mediators. However, no clinical study has tested whether AE could promote any effect on airway remodeling in asthmatic patients. METHODS: Treadmill aerobic exercise (AE) (12 weeks, 3x/week, 40min/session, 60-80%MaxHR) was applied to 17 persistent moderate asthmatic patients (42.11±19.13). Body mass index (BMI), lung function, induced sputum, breath condensate, whole blood analysis and CD4+ cells proliferation, 6MWT, exhaled nitric oxide, was evaluated. RESULTS: AE improved VEF3 (L) (p<0.03) and PEF (L/min) (p<0.005) and PEF (%) (p<0.004), reduced the number of total leukocytes, eosinophils, neutrophils, lymphocytes and macrophages (p<0.01), as well as the levels of IL-1beta, IL-4, IL-5, IL-6, IL-8, IL-13, IL-17, IL-23 (p<0.01) in induced sputum. AE also reduced the levels of IL-1beta, IL-5, IL-6, IL-13, VEGF (p<0.01), while increased the levels of anti-inflammatory IL-1ra and IL-10 (p<0.01) and anti-fibrotic Relaxin 3 (p<0.01) in breath condensate. Systemically, AE reduced the number of eosinophils, neutrophils and lymphocytes (p<0.01), as well as the levels of IL-1beta, IL-5, IL-6, IL-13, VEGF (p<0.01), while increased anti-inflammatory IL-1ra, IL-10 (p<0.01) and anti-fibrotic Relaxin 3 (p<0.01) in plasma. AE improved 6MWT (p<0.01) and reduced exhaled nitric oxide (p<0.01) and CD4+ cells proliferation (p<0.01). CONCLUSIONS: In conclusion, AE improves airway and systemic inflammation reducing pro-inflammatory cytokines, while increased anti-inflammatory and anti-fibrotic mediators systemically and into the lungs. CLINICAL IMPLICATIONS: These findings present unprecedented findings on auxiliary treatment and prevention of the health consequences of people with asthma through the practice of physical exercise. From a social point of view, it demonstrates a low-cost and easily accessible intervention, while from a scientific point of view, it will promote research ideas in a promising field. DISCLOSURES: No relevant relationships by thiago alves, source=Web Response no disclosure on file for Helida Aquino-Santos; No relevant relationships by RENILSON FERREIRA, source=Web Response no disclosure on file for Claudio Frison; No relevant relationships by Victor Hugo Palmeira, source=Web Response No relevant relationships by 119 Maysa Alves Rodrigues Rangel, source=Web Response No relevant relationships by Anamei Silva-Reis, source=Web Response No relevant relationships by Rodolfo Vieira, source=Web Response

The relationship between the expression of IL-13 and periostin and the severity of airway remodeling in asthmatic patients

Objective By detecting the expression of interleukin-13 (IL-13) and periostin in the airway of asthmatic patients, the pathological changes and pulmonary functions of airway tissues in asthmatic patients were evaluated, and the role of IL-13 and periostin airway remodeling in bronchial asthma was preliminarily explored. Methods The bronchial tissues adjacent to tumor nest were obtained from 12 patients with lung cancer complicated with bronchial asthma (asthmatic group) and 12 lung cancer patients without bronchial asthma (non-asthmatic group) after lung cancer resection. Pulmonary function was measured for all subjects before surgery. Pathological changes of airway tissues and degree of airway remodeling were assessed by hematoxylin-eosin (H&E) staining, masson′s trichrome staining, and periodic acid-silver methenamine (PASM) staining of paraffin-embedded sections. The expression of IL-13 and periostin in bronchial tissues were evaluated by immunohistochemistry. Results Values of the forced expiratory volume in 1 second of the predicted value (FEV1% pred) and FEV1/forced vital capacity (FEV1/FVC%) in asthmatic patients were significantly decreased compared with the non-asthmatic patients (P<0.05), indicating that lung function was impaired in asthmatic patients. There was more severe airway remodeling representing as thickening of basement membranes, collagen deposition, and increasing of goblet cells and fibroblasts in asthmatic patients than in non-asthmatic patients (all P<0.05). The expression of IL-13 and periostin were higher in asthmatic tissues than in non-asthmatic tissues (P<0.05). The immunohistochemical expression of IL-13 and periostin in bronchial tissues were positively correlated with the degree of airway remodeling in asthmatic patients, and the expression of IL-13 and periostin in bronchial tissues were positively correlated with each other. Conclusions The expression of IL-13 and periostin were increased in bronchial tissue in patients with asthma. They work together to promote the occurrence of airway remodeling, which eventually lead to a decline in lung function. Key words: Asthma; Interleukin-13; Cell adhesion molecules; Airway remodeling

Impulse oscillometry and nitrogen washout test in the assessment of small airway dysfunction in asthma: Correlation with quantitative computed tomography

ABSTRACTObjective. Small airway dysfunction (SAD) and airway remodeling influence the disease control and progression in asthma. We investigated whether impulse oscillometry (IOS) and single breath nitrogen washout (SBN2W) could be reliable tests in evaluating SAD and airway remodeling by correlating their data with radiological parameters derived from quantitative chest multidetector computed tomography (MDCT) imaging. Methods. Lung function tests were performed before and after bronchodilator. The MDCT lung scans were acquired at full inspiration and expiration using a portable spirometer to control the respiratory manoeuvres. Symptom control was assessed using the Asthma Control Test (ACT) questionnaire. Results. Twenty six patients were enrolled. The bronchial lumen area (LA) measured with MDCT lung scan, correlated inversely with airway resistance (Raw, p < 0.001) and with total and large airway oscillometric resistance (R5, p = 0.002 and R20, p = 0.006, respectively). However these two last correlations became non-significant after Bonferroni correction for multiple comparisons. The radiological quantification of air trapping correlated with Raw (p < 0.001), residual volume (RV, p < 0.001), and the slope of phase III of SBN2W (DeltaN2, p < 0.001) whereas the correlation with small airway oscillometric resistance (R5-20) was non-significant after Bonferroni adjustment. Finally, air trapping was significantly higher in patients with a fixed bronchial obstruction in comparison to patients with reversible obstruction. Conclusions. Plethysmographic method remains the main tool to investigate SAD and airway remodeling in asthmatic patients. The integration with the SBN2W test proved useful to better evaluate the small airway involvement whereas IOS showed a weaker correlation with both radiological and clinical data.

Lumen area change (Delta Lumen) between inspiratory and expiratory multidetector computed tomography as a measure of severe outcomes in asthmatic patients

Quantitative computed tomographic (QCT) biomarkers of airway morphology hold potential for understanding and monitoring regional airway remodeling in asthmatic patients. We sought to determine whether the change in airway lumen area between total lung capacity (TLC) and functional residual capacity (FRC) lung volumes measured from CT imaging data was correlated with severe outcomes in asthmatic patients. We studied 152 asthmatic patients (90 female and 62 male patients) and 33 healthy subjects (12 female and 21 male subjects) using QCT. Postprocessing of airways at generations 1 to 5 (1=trachea) was performed for wall area percentage, wall thickness percentage (WT%), lumen area at baseline total lung capacity (LATLC), lumen area at baseline functional residual capacity (LAFRC), and low attenuation area at FRC. Anew metric (reflecting remodeling, distal air trapping, or both), Delta Lumen, was determined as follows: Percentage difference in lumen area (LATLC-LAFRC)/LATLC×100. Postprocessing of 4501 airway segments was performed (3681 segments in the 152 patients with asthma and 820 segments in the 33 healthy subjects; range, 17-28 segments per subject). Delta Lumen values were negatively correlated with WT% and low attenuation area (P<.01) in asthmatic patients. Delta Lumen values were significantly lower for airway generations 3 to 5 (segmental airways) in subjects undergoing hospitalization because of exacerbation and in patients with refractory asthma requiring treatment with systemic corticosteroids. WT% and low attenuation area were positively and Delta Lumen values were negatively associated with systemic corticosteroid treatment (P<.05), suggesting that a reduced Delta Lumen value is a potential outcome biomarker in patients with severe asthma. Reduced Delta Lumen value in the central airways measured by using QCT is a promising exploratory biomarker of unstable refractory asthma that warrants further study.

Research Advances in the Role of Bromodomain-containing Protein 4 in Epithelial-mesenchymal Transition in Asthma.

Asthma is a chronic airway disease characterized by airway inflammation and airway remodeling. Chronic airway inflammation can be involved in airway remodeling in asthmatic patients by incuding epithelial-mesenchymal transition (EMT).Bromodomain-containing protein 4 (BRD4) is a key transcriptional regulator in mammals,and many evidences have shown that BRD4 plays a pivotal role in airway remodeling via nuclear factor-κB/RelA signaling pathway. This review summarizes the recent advances in the role of BRD4 in regulating EMT,with an attempt to elucidate the molecular mechanisms of asthma and inform the prevention and control of asthma.

Transcriptional profiling identifies the long noncoding RNA plasmacytoma variant translocation (PVT1) as a novel regulator of the asthmatic phenotype in human airway smooth muscle

BackgroundThe mechanism underlying nonsevere and severe asthma remains unclear, although it is commonly associated with increased airway smooth muscle (ASM) mass. Long noncoding RNAs (lncRNAs) are known to be important in regulating healthy primary airway smooth muscle cells (ASMCs), whereas changed expression has been observed in CD8 T cells from patients with severe asthma.MethodsPrimary ASMCs were isolated from healthy subjects (n = 9) and patients classified as having nonsevere (n = 9) or severe (n = 9) asthma. ASMCs were exposed to dexamethasone and FCS. mRNA and lncRNA expression was measured by using a microarray and quantitative real-time PCR. Bioinformatic analysis was used to examine relevant biological pathways. Finally, the lncRNA plasmacytoma variant translocation 1 (PVT1) was inhibited by transfection of primary ASMCs with small interfering RNAs, and the effect on ASMC phenotype was examined.ResultsThe mRNA expression profile was significantly different between patient groups after exposure to dexamethasone and FCS, and these were associated with biological pathways that might be relevant to the pathogenesis of asthma, including cellular proliferation and pathways associated with glucocorticoid activity. We also observed a significant change in lncRNA expression, yet the expression of only one lncRNA (PVT1) is decreased in patients with corticosteroid-sensitive nonsevere asthma and increased in patients with corticosteroid-insensitive severe asthma. Subsequent targeting studies demonstrated the importance of this lncRNA in controlling both proliferation and IL-6 release in ASMCs from patients with severe asthma.ConclusionslncRNAs are associated with the aberrant phenotype observed in ASMCs from asthmatic patients. Targeting PVT1 might be effective in reducing airway remodeling in asthmatic patients.

Chemokine release from human rhinovirus–infected airway epithelial cells promotes fibroblast migration

Thickening of the lamina reticularis, a feature of remodeling in the asthmatic airways, is now known to be present in young children who wheeze. Human rhinovirus (HRV) infection is a common trigger for childhood wheezing, which is a risk factor for subsequent asthma development. We hypothesized that HRV-infected epithelial cells release chemoattractants to recruit fibroblasts that could potentially contribute to thickening of the lamina reticularis. We sought to investigate whether conditioned medium from HRV-infected epithelial cells can trigger directed migration of fibroblasts. Human bronchial epithelial cells were exposed to medium alone or infected with HRV-16. Conditioned medium from both conditions were tested as chemoattractants for human bronchial fibroblasts in the xCELLigence cell migration apparatus. HRV-conditioned medium was chemotactic for fibroblasts. Treatment of fibroblasts with pertussis toxin, an inhibitor of Gαi-coupled receptors, prevented their migration. Production of epithelial chemoattractants required HRV replication. Multiplex analysis of epithelial supernatants identified CXCL10, CXCL8, and CCL5 as Gαi-coupled receptor agonists of potential interest. Subsequent analysis confirmed that fibroblasts express CXCR3 and CXCR1 receptors and that CXCL10 and, to a lesser extent, CXCL8, but not CCL5, are major contributors to fibroblast migration caused by HRV-conditioned medium. CXCL10 and CXCL8 produced from HRV-infected epithelial cells are chemotactic for fibroblasts. This raises the possibility that repeated HRV infections in childhood could contribute to the initiation and progression of airway remodeling in asthmatic patients by recruiting fibroblasts thatproduce matrix proteins and thicken the lamina reticularis.

D prostanoid receptor 2 (chemoattractant receptor–homologous molecule expressed on TH2 cells) protein expression in asthmatic patients and its effects on bronchial epithelial cells

BackgroundThe D prostanoid receptor 2 (DP2; also known as chemoattractant receptor–homologous molecule expressed on TH2 cells) is implicated in the pathogenesis of asthma, but its expression within bronchial biopsy specimens is unknown.ObjectivesWe sought to investigate the bronchial submucosal DP2 expression in asthmatic patients and healthy control subjects and to explore its functional role in epithelial cells.MethodsDP2 protein expression was assessed in bronchial biopsy specimens from asthmatic patients (n = 22) and healthy control subjects (n = 10) by using immunohistochemistry and in primary epithelial cells by using flow cytometry, immunofluorescence, and quantitative RT-PCR. The effects of the selective DP2 agonist 13, 14-dihydro-15-keto prostaglandin D2 on epithelial cell migration and differentiation were determined.ResultsNumbers of submucosal DP2+ cells were increased in asthmatic patients compared with those in healthy control subjects (mean [SEM]: 78 [5] vs 22 [3]/mm2 submucosa, P < .001). The bronchial epithelium expressed DP2, but its expression was decreased in asthmatic patients compared with that seen in healthy control subjects (mean [SEM]: 21 [3] vs 72 [11]/10 mm2 epithelial area, P = .001), with similar differences observed in vitro by primary epithelial cells. Squamous metaplasia of the bronchial epithelium was increased in asthmatic patients and related to decreased DP2 expression (rs = 0.69, P < .001). 13, 14-Dihydro-15-keto prostaglandin D2 promoted epithelial cell migration and at air-liquid interface cultures increased the number of MUC5AC+ and involucrin-positive cells, which were blocked with the DP2-selective antagonist AZD6430.ConclusionsDP2 is expressed by the bronchial epithelium, and its activation drives epithelial differentiation, suggesting that in addition to its well-characterized role in inflammatory cell migration, DP2 might contribute to airway remodeling in asthmatic patients.

Quantitative computed tomography–derived clusters: Redefining airway remodeling in asthmatic patients

BackgroundAsthma heterogeneity is multidimensional and requires additional tools to unravel its complexity. Computed tomography (CT)–assessed proximal airway remodeling and air trapping in asthmatic patients might provide new insights into underlying disease mechanisms.ObjectivesThe aim of this study was to explore novel, quantitative, CT-determined asthma phenotypes.MethodsSixty-five asthmatic patients and 30 healthy subjects underwent detailed clinical, physiologic characterization and quantitative CT analysis. Factor and cluster analysis techniques were used to determine 3 novel, quantitative, CT-based asthma phenotypes.ResultsPatients with severe and mild-to-moderate asthma demonstrated smaller mean right upper lobe apical segmental bronchus (RB1) lumen volume (LV) in comparison with healthy control subjects (272.3 mm3 [SD, 112.6 mm3], 259.0 mm3 [SD, 53.3 mm3], 366.4 mm3 [SD, 195.3 mm3], respectively; P = .007) but no difference in RB1 wall volume (WV). Air trapping measured based on mean lung density expiratory/inspiratory ratio was greater in patients with severe and mild-to-moderate asthma compared with that seen in healthy control subjects (0.861 [SD, 0.05)], 0.866 [SD, 0.07], and 0.830 [SD, 0.06], respectively; P = .04). The fractal dimension of the segmented airway tree was less in asthmatic patients compared with that seen in control subjects (P = .007). Three novel, quantitative, CT-based asthma clusters were identified, all of which demonstrated air trapping. Cluster 1 demonstrates increased RB1 WV and RB1 LV but decreased RB1 percentage WV. On the contrary, cluster 3 subjects have the smallest RB1 WV and LV values but the highest RB1 percentage WV values. There is a lack of proximal airway remodeling in cluster 2 subjects.ConclusionsQuantitative CT analysis provides a new perspective in asthma phenotyping, which might prove useful in patient selection for novel therapies.

Autocrine-regulated airway smooth muscle cell migration is dependent on IL-17–induced growth-related oncogenes

Airway smooth muscle cell (ASMC) migration is one of the proposed mechanisms underlying the increased airway smooth muscle mass seen in airway remodeling of patients with severe asthma. IL-17-related cytokines are a new subgroup of inflammatory mediators that have been suggested to play a role in regulating smooth muscle function. We hypothesized that IL-17-induced chemokine production from smooth muscle cells can contribute to migration of additional smooth muscle cells in the airways of asthmatic patients. We sought to investigate the effect of IL-17 on smooth muscle-derived chemokines and to examine the mechanisms involved in their production and contribution to the increase in airway smooth muscle migration. The effect of IL-17-induced supernatants on human ASMC migration was investigated. IL-17-induced growth-related oncogene (GRO) production and mRNA expression was assessed by using ELISA and RT-PCR, respectively. The direct effect of GROs on ASMC migration and the involvement of the CXCR2 receptor were also examined. IL-17-induced supernatants promoted ASMC migration. After IL-17 stimulation, GROs were the most abundant chemokines produced from ASMCs, and blocking their effect by using neutralizing antibodies significantly inhibited ASMC migration. In addition, a combination of recombinant human GRO-α, GRO-β, and GRO-γ was able to promote significant migration of ASMCs that was mediated through the CXCR2 receptor. These findings suggest that IL-17-induced GROs can be an important mediator of ASMC migration and therefore might contribute to the pathogenesis of airway remodeling in asthmatic patients.

Remodeling in asthma

Airway remodeling encompasses the structural alterations in asthmatic compared with normal airways. Airway remodeling in asthmatic patients involves a wide array of pathophysiologic features, including epithelial changes, increased smooth muscle mass, increased numbers of activated fibroblasts/myofibroblasts, subepithelial fibrosis, and vascular changes. Multiple cytokines, chemokines, and growth factors released from both inflammatory and structural cells in the airway tissue create a complex signaling environment that drives these structural changes. However, recent investigations have changed our understanding of asthma from a purely inflammatory disease to a disease in which both inflammatory and structural components are equally involved. Several reports have suggested that asthma primarily develops because of serious defects in the epithelial layer that allow environmental allergens, microorganisms, and toxins greater access to the airway tissue and that can also stimulate the release of mediators from the epithelium, thus contributing to tissue remodeling. Lung-resident fibroblasts and smooth muscle cells have also been implicated in the pathogenesis of airway remodeling. Remodeling is assumed to result in persistent airflow limitation, a decrease in lung function, and airway hyperresponsiveness. Asthmatic subjects experience an accelerated decrease in lung function compared with healthy subjects, which is proportionally related to the duration and severity of their disease.

Claudin-1 expression in airway smooth muscle exacerbates airway remodeling in asthmatic subjects

Increased airway smooth muscle (ASM) mass is an essential component of airway remodeling and asthma development, and there is no medication specifically against it. Tight junction (TJ) proteins, which are expressed in endothelial and epithelial cells and affect tissue integrity, might exist in other types of cells and display additional functions in the asthmatic lung. The aim of this study was to investigate the existence, regulation, and function of TJ proteins in ASM in asthmatic patients. The expression and function of TJ proteins in primary ASM cell lines, human bronchial biopsy specimens, and a murine model of asthma were analyzed by means of RT-PCR, multispectral imaging flow cytometry, immunohistochemistry, Western blotting, 5-(and-6)-carboxyfluorescein diacetate succinimidyl ester staining, tritiated thymidine incorporation, wound-healing assay, and luminometric bead array. Increased claudin-1 expression was observed in ASM of asthmatic patients, as well as in a murine model of asthma-like airway inflammation. Whereas IL-1β and TNF-α upregulated claudin-1 expression, it was downregulated by the T(H)2 cytokines IL-4 and IL-13 in primary human ASM cells. Claudin-1 was localized to the nucleus and cytoplasm but not to the cell surface in ASM cells. Claudin-1 played a central role in ASM cell proliferation, as demonstrated by increased ASM cell proliferation seen with overexpression and decreased proliferation seen with small interfering RNA knockdown of claudin-1. Overexpression of claudin-1 induced vascular endothelial growth factor and downregulated IL-6, IL-8, and IFN-γ-induced protein 10 production by ASM cells. Claudin-1 upregulation by IL-1β or TNF-α was suppressed by dexamethasone but not by rapamycin, FK506, or salbutamol. These results demonstrate that claudin-1 might play a role in airway remodeling in asthmatic patients by means of regulation of ASM cell proliferation, angiogenesis, and inflammation.

Effects of formoterol-budesonide on airway remodeling in patients with moderate asthma

To evaluate the effect of inhaled formoterol-budesonide on airway remodeling in adult patients with moderate asthma. Thirty asthmatic patients and thirty control subjects were enrolled. Asthmatic subjects used inhaled Symbicort 4.5/160 μg twice daily for one year. The effect of formoterol-budesonide on airway remodeling was assessed with comparing high-resolution computer tomography (HRCT) images of asthmatic patients and controls, as well as expression levels of cytokines and growth factors, inflammatory cell count in induced sputum, and airway hyper-responsiveness. The differences in age and gender between the two groups were not significant. However, differences in FVC %pred, FEV(1) %pred, and PC(20) between the two groups were significant. After treatment with formoterol-budesonide, the asthma patients' symptoms were relieved, and their lung function was improved. The WT and WA% of HRCT images in patients with asthma was increased, whereas treatment with formoterol-budesonide caused these values to decrease. The expression of MMP-9, TIMP-1, and TGF-β(1) in induced sputum samples increased in patients with asthma and decreased dramatically after treatment with formoterol-budesonide. The WT and WA% are correlated with the expression levels of cytokines and growth factors, inflammatory cell count in induced sputum, and airway hyper-responsiveness, while these same values are correlated negatively with FEV(1)/FVC and FEV(1)%. Formoterol-budesonide might interfere in chronic inflammation and airway remodeling in asthmatic patients. HRCT can be used to effectively evaluate airway remodeling in asthmatic patients.

Induction of early growth-response factor 1 by platelet-derived growth factor in human airway smooth muscle.

Platelet-derived growth factors (PDGF) may contribute to the activation and growth of smooth muscle that is characteristic of airway remodeling in asthmatic patients. Early growth response 1 (EGR-1) is a transcription factor that is induced in several cell types by PDGF and may mediate some of the effects of PDGF. We show that human airway smooth muscle cells in cell culture express EGR-1 1 h after addition of PDGF. Analysis of the EGR-1 promoter indicates that a serum response element located between 663 and 654 bp 5' to the ATG start site is essential for this induction. Serum response factor, E26 transcription factor-like protein 1, and serum protein 1 bind to this region. PDGF causes phosphorylation of ERK1/2 and is temporally associated with E26 transcription factor-like protein 1 phosphorylation. Finally, the specific ERK1/2 inhibitor U-0126 abolishes PDGF-induced expression of EGR-1 in these cells. On the basis of these data, we speculated that EGR-1 would be increased in airway smooth muscle of asthmatic patients compared with nonasthmatic controls. Using immunohistochemistry, we found that EGR-1 protein was expressed in airway smooth muscle cells and epithelial cells of asthmatic patients and nonasthmatic controls; however, there was no significant difference in the intensity of staining between groups. EGR-1 was similarly expressed in the lungs of mice with and without ovalbumin-induced airway inflammation; however, there was no difference between groups by immunohistochemistry and quantitative PCR. Although EGR-1 is induced by PDGF in human airway smooth muscle cells in cell culture, the role of EGR-1 in airway remodeling and asthma remains to be established.

Thrombin in the airways of asthmatic patients.

The mechanism of airway remodeling in asthmatic patients is poorly understood. Thrombin is a multifunctional protease that, in addition to its critical role in thrombotic processes, has also been described as inducing cellular and molecular events relevant to tissue remodeling. The present investigation was undertaken to evaluate the activity of thrombin in the sputum of asthmatic patients and its potential role in airway remodeling. The study population comprised 8 healthy subjects and 14 stable patients with bronchial asthma. The concentrations of thrombin, thrombin-antithrombin complex (TAT), and tissue factor were measured in the sputum of all subjects. The concentrations of thrombin (p = 0. 007), TAT (p = 0.01), and tissue factor (p = 0.02) in sputum were significantly higher in asthmatic patients than in healthy controls. The proliferative effects that sputum from asthmatic patients (p = 0. 01) and thrombin (p = 0.03) have on cultured human smooth muscle cells was inhibited significantly in the presence of recombinant hirudin, a specific thrombin inhibitor. Significant statistical correlation was observed between the degree of bronchial responsiveness and the sputum concentrations of thrombin (r = -0.8; p = 0.02) and TAT (r = -0.9; p = 0.01). The results of this study showed that increased thrombin generation occurs in the airway of patients with asthma and that it may play a role in the pathogenesis of airway remodeling. Further studies should be carried out to assess whether these findings are also observed in other airway diseases.