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Revista Medica de Chile May 2014The first line of defense to maintain the sterility of the intrapulmonary airways is the mucociliary clearance system. This rapidly responding, non-specific, immune... (Review)
Review
The first line of defense to maintain the sterility of the intrapulmonary airways is the mucociliary clearance system. This rapidly responding, non-specific, immune defensive system is challenged by approximately 12,000 liters of air filtered by the lungs each day, containing millions of particles like spores, environmental and eventually toxic pollutants. The main components of this system are the floating mucus "blanket", the underlying mucus propelling cilia with periciliary fluid, and the airway epithelium with secretory and ciliated type of cells. The fine and coordinated regulation of these three components is critical for an effective performance. Deregulation resulting from continuous insults, inherited ion channel disease, infections or abnormal immune response may lead to mucus alterations, goblet cell hyperplasia and metaplasia, airway obstruction, air trapping and chronic lung disease. Options for treatment are limited. Understanding this system may reveal new targets for treatment of lung disease.
Topics: Cilia; Humans; Lung Diseases; Mucociliary Clearance; Mucus
PubMed: 25427018
DOI: 10.4067/S0034-98872014000500009 -
Marine Drugs Sep 2018Jellyfish respond quickly to external stress that stimulates mucus secretion as a defense. Neither the composition of secreted mucus nor the process of secretion are...
BACKGROUND
Jellyfish respond quickly to external stress that stimulates mucus secretion as a defense. Neither the composition of secreted mucus nor the process of secretion are well understood.
METHODS
jellyfish were stimulated by removing them from environmental seawater. Secreted mucus and tissue samples were then collected within 60 min, and analyzed by a combination of proteomics and metabolomics using liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) and ultra-performance liquid chromatography/quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS/MS), respectively.
RESULTS
Two phases of sample collection displayed a quick decrease in volume, followed by a gradual increase. A total of 2421 and 1208 proteins were identified in tissue homogenate and secreted mucus, respectively. Gene Ontology (GO) analysis showed that the mucus-enriched proteins are mainly located in extracellular or membrane-associated regions, while the tissue-enriched proteins are distributed throughout intracellular compartments. Tryptamine, among 16 different metabolites, increased with the largest-fold change value of 7.8 in mucus, which is consistent with its involvement in the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway 'tryptophan metabolism'. We identified 11 metalloproteinases, four serpins, three superoxide dismutases and three complements, and their presence was speculated to be related to self-protective defense.
CONCLUSIONS
Our results provide a composition profile of proteins and metabolites in stress-induced mucus and tissue homogenate of This provides insight for the ongoing endeavors to discover novel bioactive compounds. The large increase of tryptamine in mucus may indicate a strong stress response when jellyfish were taken out of seawater and the active self-protective components such as enzymes, serpins and complements potentially play a key role in innate immunity of jellyfish.
Topics: Animals; Chromatography, High Pressure Liquid; Complement System Proteins; Enzymes; Immunity, Innate; Metabolomics; Mucus; Proteomics; Scyphozoa; Serpins; Stress, Physiological; Tandem Mass Spectrometry
PubMed: 30231483
DOI: 10.3390/md16090341 -
Advanced Drug Delivery Reviews Feb 2009Respiratory gene therapy has been considered for the treatment of a broad range of pulmonary disorders. However, respiratory secretions form an important barrier towards... (Review)
Review
Respiratory gene therapy has been considered for the treatment of a broad range of pulmonary disorders. However, respiratory secretions form an important barrier towards the pulmonary delivery of therapeutic nucleic acids. In this review we will start with a brief description of the biophysical properties of respiratory mucus and alveolar fluid. This must allow the reader to gain insights into the mechanisms by which respiratory secretions may impede the gene transfer efficiency of nucleic acid containing nanoparticles (NANs). Subsequently, we will summarize the efforts that have been done to understand the barrier properties of respiratory mucus and alveolar fluid towards the respiratory delivery of therapeutic nucleic acids. Finally, new and current strategies that can overcome the inhibitory effects of respiratory secretions are discussed.
Topics: Animals; Bronchoalveolar Lavage Fluid; Diffusion; Expectorants; Gene Transfer Techniques; Genetic Therapy; Humans; Lung Diseases; Models, Biological; Mucus; Nanoparticles; Nucleic Acids; Respiratory Mucosa; Sputum
PubMed: 19146894
DOI: 10.1016/j.addr.2008.09.011 -
Allergology International : Official... Jul 2024
Topics: Humans; Asthma; Mucus
PubMed: 38906642
DOI: 10.1016/j.alit.2024.06.001 -
PloS One 2020Airway obstruction due to decreased airway diameter and increased incidence of mucus plugs has not been directly observed in asthma exacerbation. We studied the changes...
BACKGROUND
Airway obstruction due to decreased airway diameter and increased incidence of mucus plugs has not been directly observed in asthma exacerbation. We studied the changes in the inner diameter of the airway (Din) and the frequency of mucus plugs by airway generation in patients with asthma exacerbation. We compared these patients to those in a stable phase using high-resolution computed tomography (HRCT).
METHODS AND FINDINGS
Thirteen patients with asthma were studied by HRCT during asthma exacerbation and in a stable period. The HRCT study was performed on patients who could safely hold their breath for a short while in a supine position 1 hour after initial treatment for asthma exacerbation. Using a curved multiplanar reconstruction (MPR) software, we reconstructed the longitudinal airway images and the images exactly perpendicular to the airway axis to measure the Din and mucus plugs from the second- (segmental) to sixth-generation bronchi in all segments of the lungs.The ratios of Din (exacerbation/stable) were 0.91(P = 0.016), 0.88 (P = 0.002), 0.83 (P = 0.001), 0.80 (P = 0.001), and 0.87 (NS) in the second-, third-, fourth-, fifth-, and sixth-generation bronchi, respectively. The percentages of airway obstruction due to mucus plugs were notably higher in the fourth- and fifth-generation bronchi (17.9%/18.1% in stable phase and 43.2%/45.9% in the exacerbation phase, respectively) than in the other generations of bronchi.
CONCLUSIONS
Among the bronchi examined, the fourth- and fifth-generation bronchi were significantly obstructed during asthma exacerbation compared with the stable phase in terms of a decreased airway diameter and mucus plugs.
Topics: Airway Obstruction; Asthma; Bronchi; Female; Humans; Male; Middle Aged; Mucus; Prognosis; Tomography, X-Ray Computed
PubMed: 32106233
DOI: 10.1371/journal.pone.0229238 -
The European Respiratory Journal Jul 1997The airway mucosa is lined by a continuous epithelium comprised of multiple cell phenotypes, several of which are secretory. Secretions produced by these cells mix with... (Review)
Review
The airway mucosa is lined by a continuous epithelium comprised of multiple cell phenotypes, several of which are secretory. Secretions produced by these cells mix with a variety of macromolecules, ions and water to form a respiratory tract fluid that protects the more distal airways and alveoli from injury and infection. The present article highlights the structure of the mucosa, particularly its secretory cells, gives a synopsis of the structure of mucus, and provides new information on the localization of mucin (MUC) genes that determine the peptide sequence of the protein backbone of the glycoproteins, which are a major component of mucus. Airway secretory cells comprise the mucous, serous, Clara and dense-core granulated cells of the surface epithelium, and the mucous and serous acinar cells of the submucosal glands. Several transitional phenotypes may be found, especially during irritation or disease. Respiratory tract mucins constitute a heterogeneous group of high molecular weight, polydisperse richly glycosylated molecules: both secreted and membrane-associated forms of mucin are found. Several mucin (MUC) genes encoding the protein core of mucin have been identified. We demonstrate the localization of MUC gene expression to a number of distinct cell types and their upregulation both in response to experimentally administered lipopolysaccharide and cystic fibrosis.
Topics: Animals; Gene Expression; Humans; Mucins; Mucous Membrane; Mucus; Respiratory System
PubMed: 9230262
DOI: 10.1183/09031936.97.10071655 -
Proceedings of the American Thoracic... Nov 2006Characteristic pathologic changes in chronic obstructive pulmonary disease (COPD) include an increased fractional volume of bronchiolar epithelial cells, fibrous... (Review)
Review
Characteristic pathologic changes in chronic obstructive pulmonary disease (COPD) include an increased fractional volume of bronchiolar epithelial cells, fibrous thickening of the airway wall, and luminal inflammatory mucus exudates, which are positively correlated with airflow limitation and disease severity. The mechanisms driving general epithelial expansion, mucous secretory cell hyperplasia, and mucus accumulation must relate to the effects of initial toxic exposures on patterns of epithelial stem and progenitor cell proliferation and differentiation, eventually resulting in a self-perpetuating, and difficult to reverse, cycle of injury and repair. In this review, current concepts in stem cell biology and progenitor-progeny relationships related to COPD are discussed, focusing on the factors, pathways, and mechanisms leading to mucous secretory cell hyperplasia and mucus accumulation in the airways. A better understanding of alterations in airway epithelial phenotype in COPD will provide a logical basis for novel therapeutic approaches.
Topics: Bronchi; Cell Differentiation; Cell Proliferation; Humans; Hyperplasia; Metaplasia; Mucus; Pulmonary Disease, Chronic Obstructive; Respiratory Mucosa; Stem Cells
PubMed: 17065380
DOI: 10.1513/pats.200605-117SF -
Trends in Microbiology Feb 2018Glycans form a highly variable constituent of our mucosal surfaces and profoundly affect our susceptibility to infection and disease. The diversity and importance of... (Review)
Review
Glycans form a highly variable constituent of our mucosal surfaces and profoundly affect our susceptibility to infection and disease. The diversity and importance of these surface glycans can be seen in individuals who lack a functional copy of the fucosyltransferase gene, FUT2. Representing around one-fifth of the population, these individuals have an altered susceptibility to many bacterial and viral infections and diseases. The mediation of host-pathogen interactions by mucosal glycans, such as those added by FUT2, is poorly understood. We highlight, with specific examples, important mechanisms by which host glycans influence infection dynamics, including by: acting as pathogen receptors (or receptor-decoys), promoting microbial stability, altering the physical characteristics of mucus, and acting as immunological markers. We argue that the effect glycans have on infection dynamics has profound implications for many aspects of healthcare and policy, including clinical management, outbreak control, and vaccination policy.
Topics: Adhesins, Bacterial; Antibodies; Bacteria; Bacterial Infections; Communicable Diseases; Disease Susceptibility; Fucosyltransferases; Host-Pathogen Interactions; Humans; Microbiota; Mucus; Polysaccharides; Virus Diseases; Galactoside 2-alpha-L-fucosyltransferase
PubMed: 29079498
DOI: 10.1016/j.tim.2017.09.011 -
Biomechanics and Modeling in... Feb 2023Mucus layer movement inside the airway system is an important phenomenon as the first defensive mechanism against pathogens. This research deals with the mucus velocity...
Mucus layer movement inside the airway system is an important phenomenon as the first defensive mechanism against pathogens. This research deals with the mucus velocity variations inside the nasal cavity using two different power law and thixotropic mucus layers. The cilia movement is replaced with four cyclic velocity profiles at the lower boundary of the mucus layer, while the upper boundary is exposed to the free-slip condition. The effects of boundary conditions and different fluid parameters are evaluated on the mucus flow. Furthermore, the replacement of power law and thixotropic mucus layers with a high viscous Newtonian mucus is examined under the free-slip condition at the mucus upper boundary. The adaptation rate is used as the criteria for replacing fluids instead of each other. The results show the mucus flow has enough time to adjust the changes from the lower boundary and the recovery stroke does not affect the mucus velocity in the effective stroke. Moreover, it is observed that the mucus flow variations are the same under the influence of recovery, breakdown, and breakdown exponent parameters. However, the effects of the exponent parameter on the mucus flow are more than the other two parameters in the recovery stroke. It is concluded that the assumption for replacing the power law mucus with a high viscous Newtonian one is acceptable. However, this assumption leads to the maximum error of 98.5% for thixotropic mucus in the recovery stroke.
Topics: Mucociliary Clearance; Cilia; Models, Biological; Mucus; Viscosity
PubMed: 36222949
DOI: 10.1007/s10237-022-01645-7 -
The Journal of Infection Jan 2011Understanding respiratory pathogen transmission is essential for public health measures aimed at reducing pathogen spread. Particle generation and size are key... (Review)
Review
Understanding respiratory pathogen transmission is essential for public health measures aimed at reducing pathogen spread. Particle generation and size are key determinant for pathogen carriage, aerosolisation, and transmission. Production of infectious respiratory particles is dependent on the type and frequency of respiratory activity, type and site of infection and pathogen load. Further, relative humidity, particle aggregation and mucus properties influence expelled particle size and subsequent transmission. Review of 26 studies reporting particle sizes generated from breathing, coughing, sneezing and talking showed healthy individuals generate particles between 0.01 and 500 μm, and individuals with infections produce particles between 0.05 and 500 μm. This indicates that expelled particles carrying pathogens do not exclusively disperse by airborne or droplet transmission but avail of both methods simultaneously and current dichotomous infection control precautions should be updated to include measures to contain both modes of aerosolised transmission.
Topics: Aerosols; Disease Transmission, Infectious; Humans; Humidity; Mucus; Particle Size; Particulate Matter; Respiratory Tract Infections
PubMed: 21094184
DOI: 10.1016/j.jinf.2010.11.010