Anti-VEGF treatment suppresses remodeling factors and restores epithelial barrier function through the E-cadherin/ß-catenin signaling axis in experimental asthma models.

Besides maintaining a physical barrier with adherens junctional (AJ) and tight junctional proteins, airway epithelial cells have important roles in modulating the inflammatory processes of allergic asthma. E-cadherin and ß-catenin are the key AJ proteins that are involved in airway remodeling. Various mediators such as transforming growth factor-ß (TGF-ß), epidermal growth factor (EGF), fibroblast growth factor (FGF), platelet derived growth factor (PDGF), insulin-like growth factor (IGF), tumor necrosis factor-α (TNF-α) and angiogenic factors, such as vascular endothelial growth factor (VEGF), are released by the airway epithelium in allergic asthma. The signaling pathways activated by these growth factors trigger epithelial-mesenchymal transition (EMT), which contributes to fibrosis and subsequent downregulation of E-cadherin. The present study used a mouse asthma model to investigate the effects of anti-VEGF, anti-TNF and corticosteroid therapies on growth factor and E-cadherin/ß-catenin expression. The study used 38 male BALB/c mice, divided into 5 groups. A chronic mouse asthma model was created by treating 4 of the groups with inhaled and intraperitoneal ovalbumin (n= 8 per group). Saline, anti-TNF-α (etanercept), anti-VEGF (bevacizumab) or a corticosteroid (dexamethasone) were applied to each group by intraperitoneal injection. No medication was administered to the control group (n=6). Immunohistochemistry for E-cadherin, ß-catenin and growth factors was performed on lung tissues and protein expression levels assessed using H-scores. Statistically significant differences were observed in E-cadherin, ß-catenin, EGF, FG, and PFGF (P<0.001 for all) as well as the IGF H-scores between the five groups (P<0.005). Only anti-VEGF treatment caused E-cadherin and ß-catenin levels to increase to the level of non-asthmatic control groups (P>0.005). All treatment groups had reduced TGF-ß, PDGF and FGF H-scores in comparison with the untreated asthma group (P=0.001). The EGF and IGF levels were not significantly different between the untreated asthmatic and non-asthmatic controls. The results suggested that anti-VEGF and TNF-α inhibition treatments are effective in decreasing growth factors, in a similar manner to conventional corticosteroid treatments. Anti-VEGF and TNF inhibition therapy may be an effective treatment for remodeling in asthma while offering an alternative therapeutic option to steroid protective agents. The data suggested that anti-VEGF treatment offered greater restoration of the epithelial barrier than both anti-TNF-α and corticosteroid treatment.

Clinical Usefulness of Acute-Phase Markers in Distinguishing between PFAPA and Other Exudative Tonsillitis Causes: A Methodological Study.

BACKGROUND: We investigated the practical use of procalcitonin (PCT), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) and complete blood count (CBC) parameters in distinguishing periodic fever, aphthous stomatitis, pharyngitis and cervical adenitis syndrome (PFAPA) attacks from exudative tonsillitis associated with group A streptococcus (GAS) and Epstein-Barre virus (EBV). METHODS: The study population consisted of cases with exudative tonsillitis who had been subsequently diagnosed as PFAPA, EBV, and GAS tonsillitis through a period of 6 years. We retrieved the CBC, ESR, CRP and PCT data from patients' medical records. RESULTS: Of the patients, 47 (35.6%) had PFAPA, 36 (27.3%) had GAS and 49 (37.1%) had EBV tonsillitis. Median CRP, ESR and PCT values of patients with PFAPA were 78 (17-92) mg/dl, 44 (11-83) mm/h, 0.16 (0.01-1.45) ng/ml, respectively. The CRP and ESR levels were significantly higher in PFAPA and GAS groups compared with the EBV group (p = 0.001). There was no significant difference between the groups regarding the PCT levels. CONCLUSION: The study indicated no benefit of PCT in distinguishing PFAPA from the others. However, we found that CRP, ESR, and CBC parameters could be useful in identifying PFAPA and GAS than EBV tonsillitis.

Vascular endothelial growth factor antagonism restores epithelial barrier dysfunction via affecting zonula occludens proteins.

Epithelial barrier dysfunction is important in the pathogenesis of asthma and allergic responses, and is therefore a therapeutic target. The aim of the present study was to investigate the effects of dexamethasone, a classic therapeutic agent, an anti-tumor necrosis factor agent (etanercept), which is used to treat difficult cases of asthma, and an anti-vascular endothelial growth factor (VEGF) agent (bevacizumab), which is an angiogenesis inhibitor, on zonula occludens (ZO) proteins in an experimental asthma model. The experimental model of asthma was developed using intraperitoneal (IP) and inhaled administration of ovalbumin in 38 BALB/c mice, which were divided into four groups. The control group (n=6) did not receive any treatment, while the four remaining groups (n=8 per group) received an IP injection of saline, etanercept, bevacizumab or dexamethasone, respectively. Occludin, claudin and junctional adhesion molecule (JAM) were immunohistochemically stained in the left middle lobe samples using an indirect avidin-peroxidase method, after which the staining was semiquantified with H-scores. Statistically significant differences were observed in the occludin, claudin and JAM H-scores among the four groups (P<0.001). In the untreated asthma, etanercept, bevacizumab and dexamethasone groups, the median H-scores for occludin were 93, 177, 280 and 198, respectively, while the H-scores for claudin were 82, 193.5, 274 and 202.5, respectively, and the median H-scores for JAM were 130, 210, 288 and 210, respectively. Pairwise comparisons revealed that all three ZO protein H-scores were significantly lower in the saline group when compared with each treatment group. However, the H-scores of the ZO proteins were not significantly different between the etanercept and dexamethasone groups. Furthermore, the bevacizumab group exhibited higher H-scores for all the proteins compared with the dexamethasone group. Therefore, antagonism of VEGF with bevacizumab restores the epithelial barrier to a greater extent when compared with dexamethasone treatment. This result may be promising for the development of novel therapeutic agents.

IL-5, IL-8 and MMP -9 levels in exhaled breath condensate of atopic and nonatopic asthmatic children.

RATIONALE: Asthma is a heterogeneous disease, and a great majority of pediatric patients with asthma demonstrate atopic characteristics and develop a Th2 type cytokine response. Nonatopic asthma, on the other hand, is seen more rarely. METHODS: In this study, levels of IL-5, IL-8 and MMP-9 were measured in exhaled breath condensate (EBC) of the subjects to demonstrate the extent of tissue damage as well as eosinophilic and neutrophilic inflammation in children with atopic and nonatopic asthma. A total of 37 children with atopic asthma and 37 children with nonatopic asthma were enrolled in the study. Patients who exhibited protease positive aeroallergen (House dust mite, mould mix, olea, grass mix) sensitivity in allergen skin prick test were included in the atopic asthma group. To evaluate the EBC, the fluid content of the breath was collected by having the patients exhale into an EBC device, after which the IL-5, IL-8 and MMP-9 levels were assayed using the ELISA method. RESULTS: The atopic asthmatics exhibited significantly higher IL-5 levels in their EBC samples than the nonatopic asthmatics (0.271 [0.198-0.489] pg/ml and 0.198 [0.125-0.344] pg/ml, respectively, p = 0.04), while no significant differences were observed in the levels of IL-8 and MMP-9 in the EBC samples of the atopic and nonatopic asthmatics. CONCLUSIONS: IL-5 levels, as a marker of eosinophilic inflammation, were demonstrated to be higher in the children with atopic asthma when compared to those with nonatopic asthma in EBC. The fact that no significant difference was apparent in the IL-8 levels between the groups suggests that it is the severity of the disease rather than the atopic state that plays an important role in IL-8 levels. Since no difference was recorded between the groups in terms of MMP-9 levels, lung damage in asthma sufferers seems to develop independent of atopia.

E-cadherin as an epithelial barrier protein in exhaled breath condensate.

Airway epithelium plays an important role as a physical barrier and a modulator of allergic response. Junctions between cells provide epithelial integrity and barrier function. The aim of this study was to investigate the influence of atopy on airway epithelial integrity in asthma and to measure E-cadherin levels in exhaled breath condensate as an indicator epithelial damage. A total of 74 patients with asthma (35 atopic and 39 non-atopic) and 39 healthy children were enrolled in this case-control study. Sociodemographic characteristics and asthma severity parameters in the last three-month period were recorded and pulmonary function tests were performed. Blood samples were obtained to measure serum immunoglobulin E (IgE) levels and peripheral blood eosinophil count, and exhaled breath condensate (EBC) was obtained to measure E-cadherin.EBC E-cadherin levels were significantly lower in the asthmatics when compared to non-atopic controls (0.109 (0.076) versus 0.191 (0.184) ng mL(-1) respectively, p = 0.01). Atopic and non-atopic asthmatic groups had lower EBC E-cadherin levels compared to the control group. (0.112 (0.060) ng ml(-1), 0.106 (0.089) ng ml(-1) and 0.191 (0.184) ng ml(-1), p = 0.02 and p < 0.01 respectively). However, EBC E-cadherin levels were not different between atopic and non-atopic asthmatics. The results of our study support the role of E-cadherin in the pathogenesis of asthma. However, the absence of difference in E-cadherin levels between atopic and non-atopic asthmatics suggests that allergic sensitization is not the primary factor for development of epithelial barrier dysfunction in asthma.

Follicular bronchiolitis: a rare disease in children.

Follicular bronchiolitis (FB) is a benign progressive lung disease. It is characterized with lymphoplasmocellular infiltration and hyperplastic follicles in the peribronchial areas in the small airways. Follicular bronchiolitis should be considered in cases where chronic cough, recurrent upper respiratory tract infections and progressive dyspnea are observed in children. The diagnosis should be supported by lung biopsy. A 8-year old female patient presented to our hospital with complaints including continuing cough and wheezing. Bilateral extensive rales and rhonchi in the lungs were heard on auscultation and lung graphy revealed reticuloglandular appearance. Bilateral extensive septal thickennings, reticulonodular appearance, patchy bronchiectasis, bronchiolectasis and peribronchial thickennings were found on high-resolution thoracal computarized tomography. A diagnosis of follicular bronchiolitis was made as a result of lung biopsy. Improvement was observed in the complaints and findings of our patient after methylprednisolone treatment. This patient was presented to emphasize rare interstitial lung diseases should also be considered in children who present with a clinical picture of chronic bronchial obstruction and do not respond to standard treatment.