Matrilysin-1 mediates bronchiolization of alveoli, a potential premalignant change in lung cancer

Matrilysin-1 (also called matrix metalloproteinase-7) is expressed in injured lung and in cancer but not in normal epithelia. Bronchiolization of the alveoli (BOA), a potential precursor of lung cancer, is a histologically distinct type of metaplasia that is composed of cells resembling airway epithelium in the alveolar compartment. We demonstrate that there is increased expression of matrilysin-1 in human lesions and BOA in the CC10-human achaete-scute homolog-1 transgenic mouse model. Forced expression of the matrilysin-1 gene in immortalized human normal airway epithelial BEAS-2B and HPLD1 cells, which do not normally express matrilysin-1, promoted cellular migration, suggesting a functional link for BOA formation via bronchiolar cell migration. In addition, matrilysin-1 stimulated proliferation and inhibited Fas-induced apoptosis, while a knockdown by RNA interference decreased cell growth, migration, and increased sensitivity to apoptosis. Western blotting demonstrated increased levels of phospho-p38 and phospho-Erk1/2 kinases after matrilysin-1 expression. Gene expression analysis uncovered several genes that were related to cell growth, migration/movement, and death, which could potentially facilitate bronchiolization. In vivo, the formation of BOA lesions was reduced when CC10-human achaete-scute homolog-1 mice were crossed with matrilysin-1 null mice and was correlated with reduced matrilysin-1 expression in BOA. We conclude that matrilysin-1 may play an important role in the bronchiolization of alveoli by promoting proliferation, migration, and attenuation of apoptosis involving multiple genes in the MAP kinase pathway.

Constitutive expression of human keratin 14 gene in mouse lung induces premalignant lesions and squamous differentiation

Squamous cell carcinoma accounts for 20% of all human lung cancers and is strongly linked to cigarette smoking. It develops through premalignant changes that are characterized by high levels of keratin 14 (K14) expression in the airway epithelium and evolve through basal cell hyperplasia, squamous metaplasia and dysplasia to carcinoma in situ and invasive carcinoma. In order to explore the impact of K14 in the pulmonary epithelium that normally lacks both squamous differentiation and K14 expression, human keratin 14 gene hK14 was constitutively expressed in mouse airway progenitor cells using a mouse Clara cell specific 10 kDa protein (CC10) promoter. While the lungs of CC10-hK14 transgenic mice developed normally, we detected increased expression of K14 and the molecular markers of squamous differentiation program such as involucrin, loricrin, small proline-rich protein 1A, transglutaminase 1 and cholesterol sulfotransferase 2B1. In contrast, wild-type lungs were negative. Aging CC10-hK14 mice revealed multifocal airway cell hyperplasia, occasional squamous metaplasia and their lung tumors displayed evidence for multidirectional differentiation. We conclude that constitutive expression of hK14 initiates squamous differentiation program in the mouse lung, but fails to promote squamous maturation. Our study provides a novel model for assessing the mechanisms of premalignant lesions in vivo by modifying differentiation and proliferation of airway progenitor cells. © The Author 2008. Published by Oxford University Press. All rights reserved.

Achaete-scute homolog-1 linked to remodeling and preneoplasia of pulmonary epithelium

The basic helix-loop-helix protein achaete-scute homolog-1 (ASH1) is involved in lung neuroendocrine (NE) differentiation and tumor promotion in SV40 transgenic mice. Constitutive expression of human ASH-1 (hASH1) in mouse lung results in hyperplasia and remodeling that mimics bronchiolization of alveoli (BOA), a potentially premalignant lesion of human lung carcinomas. We now show that this is due to sustained cellular proliferation in terminal bronchioles and resistance to apoptosis. Throughout the airway epithelium the expression of anti-apoptotic Bcl-2 and c-Myb was increased and Akt/mTOR pathway activated. Moreover, the expression of matrix metalloproteases (MMPs) including MMP7 was specifically enhanced at the bronchiolo-alveolar duct junction and BOA suggesting that MMPs play a key role in this microenvironment during remodeling. We also detected MMP7 in 70% of human BOA lesions. Knockdown of hASH1 gene in human lung cancer cells in vitro suppressed growth by increasing apoptosis. We also show that forced expression of hASH1 in immortalized human bronchial epithelial cells decreases apoptosis. We conclude that the impact of hASH1 is not limited to cells with NE phenotype. Rather, constitutive expression of hASH1 in lung epithelium promotes remodeling through multiple pathways that are commonly activated during lung carcinogenesis. The collective results suggest a novel model of BOA formation via hASH1-induced suppression of the apoptotic pathway. Our study yields a promising new preclinical tool for chemoprevention of peripheral lung carcinomas. © 2007 USCAP, Inc All rights reserved.

Increased expression of bronchial epithelial transient receptor potential vanilloid 1 channels in severe asthma

BACKGROUND: The airway epithelium is exposed to a range of physical and chemical irritants in the environment that are known to trigger asthma. Transient receptor potential (TRP) cation channels play a central role in sensory responses to noxious physical and chemical stimuli. Recent genetic evidence suggests an involvement of transient receptor potential vanilloid 1 (TRPV1), one member of the vanilloid subfamily of TRP channels, in the pathophysiology of asthma. The functional expression of TRPV1 on airway epithelium has yet to be elucidated.

OBJECTIVE: In this study we examined the molecular, functional, and immunohistochemical expression of TRPV1 in asthmatic and healthy airways.

METHODS: Bronchial biopsy specimens and bronchial brushings were obtained from healthy volunteers (n = 18), patients with mild-to-moderate asthma (n = 24), and patients with refractory asthma (n = 22). Cultured primary bronchial epithelial cells from patients with mild asthma (n = 4), nonasthmatic coughers (n = 4), and healthy subjects (n = 4) were studied to investigate the functional role of TRPV1.

RESULTS: Quantitative immunohistochemistry revealed significantly more TRPV1 expression in asthmatic patients compared with healthy subjects, with the greatest expression in patients with refractory asthma (P = .001). PCR and Western blotting analysis confirmed gene and protein expression of TRPV1 in cultured primary bronchial epithelial cells. Patch-clamp electrophysiology directly confirmed functional TRPV1 expression in all 3 groups. In functional assays the TRPV1 agonist capsaicin induced dose-dependent IL-8 release, which could be blocked by the antagonist capsazepine. Reduction of external pH from 7.4 to 6.4 activated a capsazepine-sensitive outwardly rectifying membrane current.

CONCLUSIONS: Functional TRPV1 channels are present in the human airway epithelium and overexpressed in the airways of patients with refractory asthma. These channels might represent a novel therapeutic target for the treatment of uncontrolled asthma.

Pharmacological characterization of a noninvasive, chronic, experimental dog model of nasal congestion

The present experiments were undertaken to pharmacologically characterize a noninvasive, chronic, experimental dog model of nasal congestion with the overall goal of developing an effective tool for studying the mechanism of action of nasal decongestant drugs.

Measurement of nasal patency in anesthetized and conscious dogs

Experiments were undertaken to characterize a noninvasive chronic, model of nasal congestion in which nasal patency is measured using acoustic rhinometry. Compound 48/80 was administered intranasally to elicit nasal congestion in five beagle dogs either by syringe (0.5 ml) in thiopental sodium-anesthetized animals or as a mist (0.25 ml) in the same animals in the conscious state. Effects of mast cell degranulation on nasal cavity volume as well as on minimal cross-sectional area (A(min)) and intranasal distance to A(min) (D(min)) were studied. Compound 48/80 caused a dose-related decrease in nasal cavity volume and A(min) together with a variable increase in D(min). Maximal responses were seen at 90-120 min. Compound 48/80 was less effective in producing nasal congestion in conscious animals, which also had significantly larger basal nasal cavity volumes. These results demonstrate the utility of using acoustic rhinometry to measure parameters of nasal patency in dogs and suggest that this model may prove useful in studies of the actions of decongestant drugs.

Revascularization versus medical therapy for renal-artery stenosis

Percutaneous revascularization of the renal arteries improves patency in atherosclerotic renovascular disease, yet evidence of a clinical benefit is limited.

Interventions for enhancing adherence to treatment in adults with bronchiectasis

Background: Bronchiectasis is characterised by a widening of the airways, leading to excess mucus production and recurrent infection. It is more prevalent in women and those in middle age. Many patients with bronchiectasis do not adhere to treatments (medications, exercise and airway clearance) prescribed for their condition. The best methods to change these adherence behaviours have not been identified.
Objectives: To assess the effects of interventions to enhance adherence to any aspect of treatment in adults with bronchiectasis in terms of adherence and health outcomes, such as pulmonary exacerbations, health-related quality of life and healthcare costs.
Search methods:We searched the Cochrane Airways Gr oup Specialised Register (CAGR), which contains trial reports identified through systematic searches of CENTRAL, MEDLINE, EMBASE, CINAHL, AMED and PsycINFO, from inception to October 2015.
Selection criteria: We planned to include randomised controlled trials (RCTs) of adults with bronchiectasis that compared any intervention aimed at enhancing adherence versus no intervention, usual care or another adherence intervention. We excluded studies of those who had bronchiectasis due to cystic fibrosis.
Data collection and analysis: Two review authors (AMcC and ET) independently screened titles, abstracts and full-texts of identified studies.
Main results: Searches retrieved 36 studies reported in 37 articles; no eligible studies were identified.
Author's Conclusions: We did not identify any studies that assessed the effect of interventions to enhance adherence to treatment in bronchiectasis. Adequately powered, well-designed trials of adherence interventions for bronchiectasis are needed.

Respiratory syncytial virus infections enhance cigarette smoke induced COPD in mice

Respiratory syncytial viral (RSV) infections are a frequent cause of chronic obstructive pulmonary disease (COPD) exacerbations, which are a major factor in disease progression and mortality. RSV is able to evade antiviral defenses to persist in the lungs of COPD patients. Though RSV infection has been identified in COPD, its contribution to cigarette smoke-induced airway inflammation and lung tissue destruction has not been established. Here we examine the long-term effects of cigarette smoke exposure, in combination with monthly RSV infections, on pulmonary inflammation, protease production and remodeling in mice. RSV exposures enhanced the influx of macrophages, neutrophils and lymphocytes to the airways of cigarette smoke exposed C57BL/6J mice. This infiltration of cells was most pronounced around the vasculature and bronchial airways. By itself, RSV caused significant airspace enlargement and fibrosis in mice and these effects were accentuated with concomitant smoke exposure. Combined stimulation with both smoke and RSV synergistically induced cytokine (IL-1a, IL-17, IFN-c, KC, IL-13, CXCL9, RANTES, MIF and GM-CSF) and protease (MMP-2, -8, -12, -13, -16 and cathepsins E, S, W and Z) expression. In addition, RSV exposure caused marked apoptosis within the airways of infected mice, which was augmented by cigarette smoke exposure. RSV and smoke exposure also reduced protein phosphatase 2A (PP2A) and protein tyrosine phosphates (PTP1B) expression and activity. This is significant as these phosphatases counter smoke-induced inflammation and protease expression. Together, these findings show for the first time that recurrent RSV infection markedly enhances inflammation, apoptosis and tissue destruction in smoke-exposed mice. Indeed, these results indicate that preventing RSV transmission and infection has the potential to significantly impact on COPD severity and progression.

Pharmacological evaluation of selective α2c-adrenergic agonists in experimental animal models of nasal congestion

Nasal congestion is one of the most troublesome symptoms of many upper airways diseases. We characterized the effect of selective α2c-adrenergic agonists in animal models of nasal congestion. In porcine mucosa tissue, compound A and compound B contracted nasal veins with only modest effects on arteries. In in vivo experiments, we examined the nasal decongestant dose-response characteristics, pharmacokinetic/pharmacodynamic relationship, duration of action, potential development of tolerance, and topical efficacy of α2c-adrenergic agonists. Acoustic rhinometry was used to determine nasal cavity dimensions following intranasal compound 48/80 (1%, 75 µl). In feline experiments, compound 48/80 decreased nasal cavity volume and minimum cross-sectional areas by 77% and 40%, respectively. Oral administration of compound A (0.1-3.0 mg/kg), compound B (0.3-5.0 mg/kg), and d-pseudoephedrine (0.3 and 1.0 mg/kg) produced dose-dependent decongestion. Unlike d-pseudoephedrine, compounds A and B did not alter systolic blood pressure. The plasma exposure of compound A to produce a robust decongestion (EC(80)) was 500 nM, which related well to the duration of action of approximately 4.0 hours. No tolerance to the decongestant effect of compound A (1.0 mg/kg p.o.) was observed. To study the topical efficacies of compounds A and B, the drugs were given topically 30 minutes after compound 48/80 (a therapeutic paradigm) where both agents reversed nasal congestion. Finally, nasal-decongestive activity was confirmed in the dog. We demonstrate that α2c-adrenergic agonists behave as nasal decongestants without cardiovascular actions in animal models of upper airway congestion.

Clinical grade allogeneic human mesenchymal stem cells restore alveolar fluid clearance in human lungs rejected for transplantation

The lack of suitable donors for all solid-organ transplant programs is exacerbated in lung transplantation by the low utilization of potential donor lungs, due primarily to donor lung injury and dysfunction, including pulmonary edema. The current studies were designed to determine if intravenous clinical-grade human mesenchymal stem (stromal) cells (hMSCs) would be effective in restoring alveolar fluid clearance (AFC) in the human ex vivo lung perfusion model, using lungs that had been deemed unsuitable for transplantation and had been subjected to prolonged ischemic time. The human lungs were perfused with 5% albumin in a balanced electrolyte solution and oxygenated with continuous positive airway pressure. Baseline AFC was measured in the control lobe and if AFC was impaired (defined as

Upper limb deep vein thrombosis due to Langer's axillary arch

Langer's axillary arch is a recognized muscular anomaly characterized by an accessory muscular band crossing the axilla that rarely causes symptoms. We describe a patient who presented with an upper limb deep vein thrombosis caused by this aberrant muscle, which we believe is the first reported case. Axillary surgery with division of the aberrant muscle relieved upper limb venous obstruction in this patient. (J Vase Surg 2012;55:234-6.)

Respiratory Infections Cause the Release of Extracellular Vesicles: Implications in Exacerbation of Asthma/COPD

Background: Infection-related exacerbations of respiratory diseases are a major health concern; thus understanding the mechanisms driving them is of paramount importance. Despite distinct inflammatory profiles and pathological differences, asthma and COPD share a common clinical facet: raised airway ATP levels. Furthermore, evidence is growing to suggest that infective agents can cause the release of extracellular vesicle (EVs) in vitro and in bodily fluids. ATP can evoke the P2X7/caspase 1 dependent release of IL-1β/IL-18 from EVs; these cytokines are associated with neutrophilia and are increased during exacerbations. Thus we hypothesized that respiratory infections causes the release of EVs in the airway and that the raised ATP levels, present in respiratory disease, triggers the release of IL-1β/IL-18, neutrophilia and subsequent disease exacerbations.

Methods: To begin to test this hypothesis we utilised human cell-based assays, ex vivo murine BALF, in vivo pre-clinical models and human samples to test this hypothesis.

Results: Data showed that in a murine model of COPD, known to have increased airway ATP levels, infective challenge causes exacerbated inflammation. Using cell-based systems, murine models and samples collected from challenged healthy subjects, we showed that infection can trigger the release of EVs. When exposed to ATP the EVs release IL-1b/IL-18 via a P2X₇/caspase-dependent mechanism. Furthermore ATP challenge can cause a P2X₇ dependent increase in LPS-driven neutrophilia.

Conclusions: This preliminary data suggests a possible mechanism for how infections could exacerbate respiratory diseases and may highlight a possible signalling pathway for drug discovery efforts in this area.

Anatomy and Neurophysiology of Coughing: CHEST Guideline and Expert Panel Report

Bronchopulmonary C-fibers and a subset of mechanically sensitive, acid-sensitive myelinated sensory nerves play essential roles in regulating cough. These vagal sensory nerves terminate primarily in the larynx, trachea, carina and large intrapulmonary bronchi. Other bronchopulmonary sensory nerves, sensory nerves innervating other viscera as well as somatosensory nerves innervating the chest wall, diaphragm and abdominal musculature regulate cough patterning and cough sensitivity. The responsiveness and morphology of the airway vagal sensory nerve subtypes and the extrapulmonary sensory nerves that regulate coughing are described. The brainstem and higher brain control systems that process this sensory information are complex, but our current understanding of them is considerable and increasing. The relevance of these neural systems to clinical phenomena, such as urge to cough and psychological methods for treatment of dystussia, is high and modern imaging methods have revealed potential neural substrates for some features of cough in the human.

Chronic cough as a neuropathic disorder

Chronic cough is a common symptom that can be a daunting challenge for clinicians since treatment of the underlying cause does not always provide adequate relief, an obvious cause can remain elusive, and current antitussives have fairly poor efficacy and undesirable side-effects. Patients with chronic cough typically describe a range of sensory symptoms suggestive of upper-airway and laryngeal neural dysfunction. Additionally, patients often report cough triggered by low-level physical and chemical stimuli, which is suggestive of cough-reflex hyperresponsiveness. Pathophysiological mechanisms underlying peripheral and central augmentation of the afferent cough pathways have been identified, and compelling evidence exists for a neuropathy of vagal sensory nerves after upper-respiratory viral infections or exposure to allergic and non-allergic irritants. In this Personal View, we argue that chronic cough is a neuropathic disorder that arises from neural damage caused by a range of inflammatory, infective, and allergic factors. In support of this idea, we discuss evidence of successful treatment of chronic cough with agents used for treatment of neuropathic pain, such as gabapentin and amitriptyline. Regarding cough as a neuropathic disorder could lead to new, more effective antitussives.