Mucoactive medications and airway disease

Risk factors for nasal bleeding in patients undergoing transnasal gastrointestinal endoscopy

Transnasal endoscopy is widely used in screening for upper gastrointestinal lesions because of less associated pain. Nasal bleeding is the most severe adverse effect, but specific risk factors have not been identified. The aim of this study is to identify risk factors for nasal bleeding during transnasal endoscopy. Nasal bleeding occurred in 160/3035 (5.3%) of patients undergoing transnasal endoscopy as part of health checkups. Patient data were retrospectively evaluated including anthropometric, medical, and life-style parameters with multiple logistic regression analysis. Multiple logistic regression revealed that nasal bleeding was significantly associated with age in decades [odds ratio/10 years 0.78, 95% confidence interval (CI) 0.63-0.97, p = 0.027], female gender (2.15, 95% CI 1.48-3.12, p < 0.001), a history of previous upper gastrointestinal endoscopy (0.55, 95% CI 0.36-0.82, p = 0.004), and chronic/allergic rhinitis (0.60, 95% CI 0.36-0.98, p = 0.043). Other factors including the use of antiplatelet and/or anticoagulant drugs were not significantly associated with nasal bleeding. Female and young patients are significantly associated with an increased risk of bleeding from transnasal endoscopy, but antiplatelet and/or anticoagulant medications and a history of chronic/allergic rhinitis may not be associated.

Thermo-physical properties of synthetic mucus for the study of airway clearance

In this article, dynamic viscosity, surface tension, density, heat capacity and thermal conductivity, of a bronchial mucus simulant proposed by Zahm et al., Eur Respir J 1991; 4: 311-315 were experiementally determined. This simulant is mainly composed of a galactomannan gum and a scleroglucan. It was shown that thermophysical properties of synthetic mucus are dependant of scleroglucan concentrations. More importantly and for some scleroglucan concentrations, the syntetic mucus, exhibits, somehow, comparable thermophysical properties to real bronchial mucus. An insight on the microstructure of this simulant is proposed and the different properties enounced previously have been measured for various scleroglucan concentrations and over a certain range of operating temperatures. This synthetic mucus is found to mimic well the rheological behavior and the surface tension of real mucus for different pathologies. Density and thermal properties have been measured for the first time. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 3025-3033, 2017.

A Macroscopic Model for Simulating the Mucociliary Clearance in a Bronchial Bifurcation: The Role of Surface Tension

The mucociliary clearance in the bronchial tree is the main mechanism by which the lungs clear themselves of deposited particulate matter. In this work, a macroscopic model of the clearance mechanism is proposed. Lubrication theory is applied for thin films with both surface tension effects and a moving wall boundary. The flow field is computed by the use of a finite-volume scheme on an unstructured grid that replicates a bronchial bifurcation. The carina in bronchial bifurcations is of special interest because it is a location of increased deposition of inhaled particles. In this study, the mucus flow is computed for different values of the surface tension. It is found that a minimal surface tension is necessary for efficiently removing the mucus while maintaining the mucus film thickness at physiological levels.

Rheological study of healthy chicken's pooled tracheobronchial secretions and its modification by mucolytics drugs

The rheological properties of pooled tracheobronchial secretions (TBS) of chicken, including mucus, have not been characterized. Yet mucolytic drugs are frequently used in poultry medicine. To define such properties, TBS from healthy untreated and from chickens treated with various mucolytic drugs was studied. Three hundred, three-week-old Rhode Island Red chickens were divided into five groups, with three repetitions each (n = 20) as follows: ambroxol (GAmb), ethylene diamine dihydro-iodide (GEddi), carbocysteine (GCs), bromhexine (GBr), and an untreated control group (CG). Under anesthesia, samples of TBS were taken by gently flushing saline solution through the tracheobronchial tree, and rheological evaluations were made to determine viscosity, yield stress, and viscoelasticity by means of a rheometer using controlled efforts with a geometry system of concentric cylinders. It was found that TBS in the CG and in all treatments showed a non-Newtonian behavior (n < 1). TBS from all treatments possess yield stress (necessary force applied for a fluid to flow) and a pseudo-solid type behavior (viscoelastic test) as far as elasticity is concerned. TBS from treated animals revealed that yield stress was higher for the GBr and lowest for GAmb. Statistically significant differences in viscosity were observed among all treatments, including CG (P < 0.05). Considering yield stress, little effort would be required for respiratory cilia to displace TBS in ambroxol medicated chickens, followed by carbocysteine. Contrary to expectation, cilia from healthy chickens medicated with bromhexine or ethylene diamine dihydro-iodide, would require greater force to displace mucus as compared to untreated healthy birds.

Pharmacokinetic Studies in Healthy Subjects for the Development of an Extended-Release Tablet Formulation of Guaifenesin: A 505(b)(2) New Drug Application Approval

Guaifenesin is an expectorant used to improve mucociliary clearance (MCC) and relieve chest congestion from upper respiratory tract infections. Immediate-release (IR) guaifenesin requires dosing every 4 hours to maintain efficacy because of the drug's short half-life. Extended-release (ER) guaifenesin has been developed to prolong efficacy and reduce dosing frequency. As part of the 505(b)(2) new drug application (NDA), the pharmacokinetics (PK) of an ER bi-layer tablet formulation of guaifenesin (Mucinex®) and bioequivalence to an over-the-counter (OTC) monograph IR formulation were evaluated in healthy subjects. In one study, subjects received 1,200 mg ER guaifenesin every 12 hours or 400 mg IR guaifenesin every 4 hours for 6 days. Steady-state exposures were equivalent between the two products, as demonstrated by AUC and Cmax . In another study, subjects received a single dose of 600 mg (fasted) or 1,200 mg (fasted or fed) ER bi-layer tablet formulations. AUC and Cmax were equivalent between both states for the 1,200 mg ER dose. However, Tmax of 1,200 mg ER guaifenesin was later in the fed than the fasted state. ER guaifenesin is bioequivalent to corresponding OTC monograph doses of IR guaifenesin. ER guaifenesin offers a convenient 12-hour dosing alternative to 4-hour dosing of IR guaifenesin.

Hypertonic saline solutions do not influence the solubility of sputum from secretor and non-secretor cystic fibrosis patients

INTRODUCTION

Functional alterations of the cystic fibrosis transmembrane conductance regulator gene (CFTR) increase the viscoelasticity of pulmonary secretions of cystic fibrosis (CF) patients and require the use of therapeutic aerosols. The biochemical properties of exocrine secretions are influenced by the expression of the FUT2 gene which determine the secretor and non-secretor phenotypes of the ABH glycoconjugates. The aim of this study was to determine the influence of secretor and non-secretor phenotypes by means of photoacoustic analysis, both the typical interaction time (t(0)) and the solubilization interval (Δt) of the sputum of secretor and non-secretor CF patients nebulized by hypertonic saline solutions at different concentrations.

MATERIAL AND METHODS

Sputum samples were obtained by spontaneous expectoration from 6 secretor and 4 non-secretor patients with CF. Each sample was nebulized with 3%, 6%, and 7% hypertonic saline solutions in a photoacoustic cell. The values of t(0) and Δt were determined using the Origin 7.5(®) computer program (Microcal Software Inc.). The t-test was employed using the GraphPad Instat 3.0(®) computer program to calculate the mean and standard deviation for each parameter.

RESULTS

For all hypertonic saline solutions tested, the mean values of t(0) and Δt do not show statistically significant differences between secretor and non-secretor patients.

CONCLUSIONS

The secretor and non-secretor phenotypes do not influence the in vitro solubilization of the sputum nebulized by hypertonic saline solutions at different concentrations when analysed by photoacoustic technique.

Micro- and macrorheology of mucus

Mucus is a complex biological material that lubricates and protects the human lungs, gastrointestinal (GI) tract, vagina, eyes, and other moist mucosal surfaces. Mucus serves as a physical barrier against foreign particles, including toxins, pathogens, and environmental ultrafine particles, while allowing rapid passage of selected gases, ions, nutrients, and many proteins. Its selective barrier properties are precisely regulated at the biochemical level across vastly different length scales. At the macroscale, mucus behaves as a non-Newtonian gel, distinguished from classical solids and liquids by its response to shear rate and shear stress, while, at the nanoscale, it behaves as a low viscosity fluid. Advances in the rheological characterization of mucus from the macroscopic to nanoscopic levels have contributed critical understanding to mucus physiology, disease pathology, and the development of drug delivery systems designed for use at mucosal surfaces. This article reviews the biochemistry that governs mucus rheology, the macro- and microrheology of human and laboratory animal mucus, rheological techniques applied to mucus, and the importance of an improved understanding of the physical properties of mucus to advancing the field of drug and gene delivery.

Methods for studying mucociliary transport

Mucociliary transport dysfunctions can impair the quality of life of patients suffering from chronic rhinossinusitis and lead to severe consequences such as alterations in respiratory physiology or even death as in cases of cystic fibrosis and primary ciliary dyskinesia. Therefore, it is crucial to understand the physiology of the mucociliary apparatus and how its components (cilia, mucus-periciliary layer and its interaction) affect the clearance of respiratory secretions. Aims: This paper aims to review and to discuss different techniques for studying mucociliary transport and their clinical and experimental applicability. Conclusions: The methods listed in this revision provide us with valuable information about different aspects of the mucociliary transport. Some of the methods listed are more suitable for clinical practice and present reproducible results. Others, show only applicability in experimental settings due to technical difficulties or financial limitations. However, it is important to emphasize that up to now there is no method that can evaluate ciliary beating frequency (CBF) in vivo and in situ. Such a method would become a valuable tool in the scientific scenario and in the clinical practice, supporting the diagnosis of ciliary dyskinesias and avoiding the use of invasive procedures to corroborate the clinical suspicion

Pharmacotherapy of impaired mucociliary clearance in non-CF pediatric lung disease. A review of the literature

Mucoactive agents are used to treat a variety of lung diseases involving impaired mucociliary clearance or mucus hypersecretion. The mucoactive agents studied most frequently are N-acetylcysteine (NAC), recombinant human DNase (rhDNase), and hypertonic saline. Studies on the efficacy of these have been mainly conducted in adults, and in patients with cystic fibrosis (CF). The exact role of mucoactive agents in children with non-CF lung disease is not well established. We present an overview of the current literature reporting clinical outcome measures of treatment with NAC, rhDNase, and hypertonic saline in children.

Métodos de estudo do transporte mucociliar

Disfunções no transporte mucociliar trazem desde queda na qualidade de vida dos pacientes, como nas rinites e rinossinusites crônicas, até graves conseqüências com risco de seqüelas irreversíveis e mesmo letais, como nos casos de fibrose cística e das discinesias ciliares primárias. Desta forma, torna-se fundamental o conhecimento do funcionamento normal do aparelho mucociliar e de como alterações em seus componentes (cílio, muco-fluido periciliar e interação dinâmica entre ambos) afetam o transporte das secreções respiratórias. OBJETIVOS: Este artigo visa a revisar e discutir as diferentes técnicas de avaliação do transporte mucociliar descrevendo suas peculiaridades e aplicabilidades clínicas e experimentais. CONCLUSÕES: Os métodos citados nesta revisão nos fornecem informações importantes sobre os diferentes aspectos do transporte mucociliar. Alguns apresentam uma maior facilidade de realização e resultados reprodutíveis, já outros apenas mostraram-se com aplicabilidade em protocolos de pesquisa em virtude de dificuldades técnicas e limitações financeiras. Há que se considerar a inexistência de métodos que avaliem ambulatorialmente a freqüência de batimento ciliar (FBC) "in vivo" e "in situ", o que se tornaria uma ferramenta importante, tanto no âmbito científico, quanto na prática clínica, auxiliando no diagnóstico das discinesias ciliares e evitando a realização de procedimentos mais invasivos para a sua confirmação diagnóstica.

Reevaluating gel-forming mucins' roles in cystic fibrosis lung disease

The existence of mucus plugs, containing mucins, bacteria, and neutrophils, blocking the lower airways in the lung of cystic fibrosis (CF) patients has raised the possibility that production of "abnormal" mucins is a critical characteristic of this disease. The molecular nature, if any, of this abnormality is unknown. Recent studies suggest that CF lung disease progression is characterized by an early phase in which airway surface liquid (ASL) increased dehydration is accompanied by altered pH and levels of reduced glutathione (GSH). In a later phase, bacterial infection and neutrophil invasion lead to increased ASL of concentrations myeloperoxidase and hypochlorous acid (HOCl). Independent studies indicate that gel-forming mucins, the key components of airway mucus, form disulfide-linked polymers through a pH-dependent, likely self-catalyzed mechanism. In this article, we present the hypothesis that increased mucus concentration (dehydration) and altered pH, and levels of GSH, myeloperoxidase, and/or HOCl result in the extracellular formation of additional interchain bonds among airway mucins. These novel interactions would create an atypical mucin network with abnormal viscoelastic and adhesive properties.