Diagnostic tools assessing airway remodelling in asthma

Sputum inflammatory, neural, and remodelling mediators in eosinophilic and non-eosinophilic asthma

BACKGROUND

Neural and remodelling mechanisms may play a role in asthma, particularly non-eosinophilic asthma (NEA).

OBJECTIVE

To assess sputum mediators associated with neural, remodelling, and inflammatory mechanisms in eosinophilic asthma (EA), NEA, and non-asthmatics.

METHODS

111 participants with and 62 without asthma (14-21 years) underwent sputum induction, exhaled nitric oxide (FeNO), atopy, and spirometry tests. Twenty-four mediators were measured in sputum using ELISA or bead array. EA (n=52) and NEA (n=59) were defined using a sputum eosinophil cut-point of ≥2.5%.

RESULTS

Elevated levels of nociceptin (median: 39.1 vs 22.4 ng/mL, p=0.03), periostin (33.8 vs 9.4 ng/mL, p=0.01), and eosinophil cationic protein (ECP); (220.1 vs 83.7 ng/mL, p=0.03) were found in asthmatics compared with non-asthmatics. Nociceptin was elevated in EA (54.8 vs 22.4 ng/mL, p=0.02) compared with non-asthmatics. EA had higher levels of inflammatory (ECP: 495.5 vs 100.3 ng/mL, p≤0.01; interleukin-1β: 285.3 vs 209.3 pg/mL, p=0.03; histamine: 5805.0 vs 3172.5 pg/mL, p=<0.01) and remodelling (vascular endothelial growth factor A (VEGF-A); 3.3 vs 2.5 ng/mL, p=0.03; periostin: 47.7 vs 22.1 ng/mL, p=0.04) mediators than NEA. Whilst macrophages were associated with neural mediators e.g. neurokinin A (r=0.27, p=0.01) and nociceptin (r=0.30, p=0.02), granulocytes were associated with inflammatory/remodelling mediators; e.g. ECP and VEGF-A correlated with neutrophils (r=0.53 & r=0.33 respectively, p=<0.01) and eosinophils (r=0.53 & r=0.29 respectively, p≤0.01).

CONCLUSION

Elevated levels of nociceptin and inflammatory/remodelling markers were found in EA, but no evidence for neural and remodelling pathways was found in NEA. Neural and remodelling mechanisms appear to coexist with inflammation.

Concepts of advanced therapeutic delivery systems for the management of remodeling and inflammation in airway diseases

Chronic respiratory disorders affect millions of people worldwide. Pathophysiological changes to the normal airway wall structure, including changes in the composition and organization of its cellular and molecular constituents, are referred to as airway remodeling. The inadequacy of effective treatment strategies and scarcity of novel therapies available for the treatment and management of chronic respiratory diseases have given rise to a serious impediment in the clinical management of such diseases. The progress made in advanced drug delivery, has offered additional advantages to fight against the emerging complications of airway remodeling. This review aims to address the gaps in current knowledge about airway remodeling, the relationships between remodeling, inflammation, clinical phenotypes and the significance of using novel drug delivery methods.

Warifteine and methylwarifteine inhibited the type 2 immune response on combined allergic rhinitis and asthma syndrome (CARAS) experimental model through NF-кB pathway

CARAS is an airway inflammation of allergic individuals, with a type 2 immune response. The pharmacotherapy is based on drugs with relevant side effects. Thus, the goal of this study evaluated the alkaloids warifteine (War) and methylwarifteine (Mwar) from Cissampelos sympodialis in CARAS experimental model. Therefore, BALB/c mice were ovalbumin (OVA) sensitized and challenged and treated with both alkaloids. Treated animals showed a decrease (p < 0.05) of allergic signs as sneezing and nasal rubbings, histamine nasal hyperreactivity, and inflammatory cell migration into the nasal (NALF) and the bronchoalveolar (BALF) fluids, main eosinophils. In the systemic context, only Mwar reduced eosinophilia, however, both alkaloids reduced the serum levels of OVA-specific IgE. Histological analysis revealed that the alkaloids decreased the inflammatory cells into the subepithelial and perivascular regions of nasal tissue and the peribronchiolar and perivascular regions of lung tissue. Hyperplasia/hypertrophy of nasal and lung goblet cells were reduced in alkaloid treated animals; however, the treatment did not change the number of mast cells. The lung hyperactivity was attenuated by reducing hyperplasia of fibroblast and collagen fiber deposition and hypertrophy of the lung smooth muscle layer. The immunomodulatory effect was by decreasing of type 2 and 3 cytokines (IL-4/IL-13/IL-5 and IL-17A) dependent by the increasing of type 1 cytokine (IFN-γ) into the BALF of treated sick animals. Indeed, both alkaloids reduced the NF-кB (p65) activation on granulocytes and lymphocytes, indicating that the alkaloids shut down the intracellular transduction signals underlie the transcription of T_H2 cytokine gens.

Airway Evaluation with Multidetector Computed Tomography Post-Processing Methods in Asthmatic Patients

Asthma is a chronic inflammatory obstructive airways disease. The disease occurs regardless of age and manifests with cough, attacks of breathlessness, and tightness in the chest. The pathophysiology of asthma is complex and still not fully understood. It is essential to find answers concerning the role of each part of the bronchial tree in asthma, especially the role of small bronchioles. With the development of newer generations of multidetector computed tomography (MDCT) and advanced post-processing methods it is possible to obtain more detailed images and gain insight into further aspects of asthma. MDCT post-processing methods can be divided into two-dimensional (2D) and three-dimensional (3D). In 2D projections, visualized hypodense regions correspond to the airway flow limitations. With the more advanced methods, such as multi planar reconstructions (MPR), images in different planes (axial, coronal, or sagittal) can be created. In the MPR technique only the voxels which are adjacent to each other in the predetermined plane can be extracted from the data set. Using the minimal/maximal intensity projections and shaded surface display, the volume of interest (VOI) can be extracted. High resolution CT scans can be used to create a more advanced imaging tool - the virtual bronchoscopy (VB). Using the VB makes it possible to visualize regions of obturation in the bronchi of up to the 5-8th generation. The MDCT with advanced post-processing methods is likely to assume an important role in the differential diagnosis of asthma, particularly when the diagnosis is dubious or hard to settle due to accompanying other lung diseases.

An orally active geranyl acetophenone attenuates airway remodeling in a murine model of chronic asthma

2,4,6-Trihydroxy-3-geranyl acetophenone (tHGA) is a synthetic compound that is naturally found in Melicope ptelefolia. We had previously demonstrated that parenteral administration of tHGA reduces pulmonary inflammation in OVA-sensitized mice. In this study, we evaluated the effect of orally administered tHGA upon airway remodeling in a murine model of chronic asthma. Female BALB/C mice were sensitized intraperitoneally with ovalbumin (OVA) on day 0, 7 and 14, followed by aerosolized 1% OVA 3 times per week for 6 weeks. Control groups were sensitized with saline. OVA sensitized animals were either treated orally with vehicle (saline with 1% DMSO and Tween 80), tHGA (80, 40, 20mg/kg) or zileuton (30mg/kg) 1h prior to each aerosolized OVA sensitization. On day 61, mice underwent methacholine challenge to determine airway hyperresponsiveness prior to collection of bronchoalveolar lavage (BAL) fluid and lung samples. BAL fluid inflammatory cell counts and cytokine concentrations were evaluated while histological analysis and extracellular matrix protein concentrations were determined on collected lung samples. Oral tHGA treatment attenuated airway hyperresponsiveness and inhibited airway remodeling in a dose-dependent fashion. tHGA's effect on airway remodeling could be attributed to the reduction of inflammatory cell infiltration and decreased expression of cytokines associated with airway remodeling. Oral administration of tHGA attenuates airway hyperresponsiveness and remodeling in OVA-induced BALB/c mice. tHGA is an interesting compound that should be evaluated further for its possible role as an alternative non-steroidal pharmacological approach in the management of asthma.

The Protective Effect of Naringin against Bleomycin-Induced Pulmonary Fibrosis in Wistar Rats

The aim of the current study was to investigate the protective effect of naringin on bleomycin-induced pulmonary fibrosis in rats. Twenty-four Wistar rats randomly divided into four groups (control, bleomycin alone, bleomycin + naringin 40, and bleomycin + naringin 80) were used. Rats were administered a single dose of bleomycin (5 mg/kg; via the tracheal cannula) alone or followed by either naringin 40 mg/kg (orally) or naringin 80 mg/kg (orally) or water (1 mL, orally) for 14 days. Rats and lung tissue were weighed to determine the lung index. TNF-α and IL-1β levels, hydroxyproline content, and malondialdehyde (MDA) levels were assayed. Glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) activities were determined. Tissue sections were stained with hematoxylin-eosin, Masson's trichrome, and 0.1% toluidine blue. TNF-α, IL-1β, and MDA levels and hydroxyproline content significantly increased (p < 0.01) and GPx and SOD activities significantly decreased in bleomycin group (p < 0.01). Naringin at a dose of 80 mg/kg body weight significantly decreased TNF-α and IL-1β activity, hydroxyproline content, and MDA level (p < 0.01) and increased GPx and SOD activities (p < 0.05). Histological evidence supported the results. These results show that naringin has the potential of reducing the toxic effects of bleomycin and may provide supportive therapy for conventional treatment methods for idiopathic pulmonary fibrosis.

AVE 0991, a non-peptide mimic of angiotensin-(1-7) effects, attenuates pulmonary remodelling in a model of chronic asthma

BACKGROUND AND PURPOSE

AVE 0991 (AVE) is a non-peptide compound, mimic of the angiotensin (Ang)-(1-7) actions in many tissues and pathophysiological states. Here, we have investigated the effect of AVE on pulmonary remodelling in a murine model of ovalbumin (OVA)-induced chronic allergic lung inflammation.

EXPERIMENTAL APPROACH

We used BALB/c mice (6-8 weeks old) and induced chronic allergic lung inflammation by OVA sensitization (20 μg·mouse(-1) , i.p., four times, 14 days apart) and OVA challenge (1%, nebulised during 30 min, three times per·week, for 4 weeks). Control and AVE groups were given saline i.p and challenged with saline. AVE treatment (1 mg·kg(-1) ·per day, s.c.) or saline (100 μL·kg(-1) ·per day, s.c.) was given during the challenge period. Mice were anaesthetized 72 h after the last challenge and blood and lungs collected. In some animals, primary bronchi were isolated to test contractile responses. Cytokines were evaluated in bronchoalveolar lavage (BAL) and lung homogenates.

KEY RESULTS

Treatment with AVE of OVA sensitised and challenged mice attenuated the altered contractile response to carbachol in bronchial rings and reversed the increased airway wall and pulmonary vasculature thickness and right ventricular hypertrophy. Furthermore, AVE reduced IL-5 and increased IL-10 levels in the BAL, accompanied by decreased Ang II levels in lungs.

CONCLUSIONS AND IMPLICATIONS

AVE treatment prevented pulmonary remodelling, inflammation and right ventricular hypertrophy in OVA mice, suggesting that Ang-(1-7) receptor agonists are a new possibility for the treatment of pulmonary remodelling induced by chronic asthma.

Electroacupuncture Attenuates Ovalbumin-Induced Allergic Asthma via Modulating CD4(+)CD25(+) Regulatory T Cells

A mouse pulmonary hypersensitivity experimental model that mimics human asthma was developed, and electroacupuncture (EA) treatment was shown to reduce allergic inflammatory processes. In addition, we also assessed whether the beneficial effects of EA on allergic asthma could be correlated with CD4⁺CD25⁺Foxp3⁺ regulatory T cells (Treg). Cellular profiles and histopathologic analysis demonstrated that peribronchial and perivascular inflammatory cell infiltrates were significantly decreased in the EA-treated groups when compared to the OVA and anti-CD25 Ab-injected (Treg depletion) groups. Furthermore, total BAL cells were reduced in the EA groups when compared to other groups. Interestingly, the population of CD4⁺CD25⁺Foxp3⁺Tregs in pneumonocytes increased in EA-treated group when compared to OVA and Treg depletion groups. These results imply that EA stimulation at ST 36 may affect CD4⁺CD25⁺Foxp3⁺ Treg in an OVA-induced experimental model and may enhance Treg function by suppressing other T cells and limiting the immune response.