Mucus and Airway Epithelium Alterations in Cystic Fibrosis

Puchelle, Édith; Zahm, Jean‐Marie; Bentzmann, Sophie de; Gaillard, Dominique

doi:10.1007/978-3-0348-8874-5_12

Cited by 5 publications

(7 citation statements)

References 79 publications

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“…However, we estimated the percent dry weight (percentage of solids) of normal mucus at ϳ1.5-2.5% and of thick CF-like mucus at ϳ6 -15%, based on data reported from cell culture (26), a mouse model (4), and human studies (27)(28)(29)(30)(31)(32)(33). Mucus of 1.5% solids may be less than the normal optimal concentration because the network of mucin fibers and transport were heterogeneous (Fig.…”

Section: Figurementioning

confidence: 99%

“…1C), may reflect the concentration of mucins that occurs in larger airways due to increased mucin secretion and ASL volume absorption (36). The higher concentration of mucus we operationally chose to mimic CF, 6.5%, likely represents the minimum concentration found in CF airways before infection (29,30,32,33). Mucus transport assays demonstrated that 6.5% mucus was too thick to be transported by cilia, mimicking a key feature of CF mucus (2).…”

Section: Figurementioning

confidence: 99%

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Reduced Three-Dimensional Motility in Dehydrated Airway Mucus Prevents Neutrophil Capture and Killing Bacteria on Airway Epithelial Surfaces

Matsui¹,

Verghese²,

Kesımer

et al. 2005

The Journal of Immunology

129

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Cystic fibrosis (CF) lung disease is characterized by persistent lung infection. Thickened (concentrated) mucus in the CF lung impairs airway mucus clearance, which initiates bacterial infection. However, airways have other mechanisms to prevent bacterial infection, including neutrophil-mediated killing. Therefore, we examined whether neutrophil motility and bacterial capture and killing functions are impaired in thickened mucus. Mucus of three concentrations, representative of the range of normal (1.5 and 2.5% dry weight) and CF-like thickened (6.5%) mucus, was obtained from well-differentiated human bronchial epithelial cultures and prepared for three-dimensional studies of neutrophil migration. Neutrophil chemotaxis in the direction of gravity was optimal in 1.5% mucus, whereas 2.5% mucus best supported neutrophil chemotaxis against gravity. Lateral chemokinetic movement was fastest on airway epithelial surfaces covered with 1.5% mucus. In contrast, neutrophils exhibited little motility in any direction in thickened (6.5%) mucus. In in vivo models of airway mucus plugs, neutrophil migration was inhibited by thickened mucus (CF model) but not by normal concentrations of mucus (“normal” model). Paralleling the decreased neutrophil motility in thickened mucus, bacterial capture and killing capacity were decreased in CF-like thickened mucus. Similar results with each mucus concentration were obtained with mucus from CF cultures, indicating that inhibition of neutrophil functions was mucus concentration dependent not CF source dependent. We conclude that concentrated (“thick”) mucus inhibits neutrophil migration and killing and is a key component in the failure of defense against chronic airways infection in CF.

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Section: Figurementioning

confidence: 99%

Section: Figurementioning

confidence: 99%

Reduced Three-Dimensional Motility in Dehydrated Airway Mucus Prevents Neutrophil Capture and Killing Bacteria on Airway Epithelial Surfaces

Matsui¹,

Verghese²,

Kesımer

et al. 2005

The Journal of Immunology

129

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“…Although measurements of mucus concentration, i.e., the percentage of solids content, from CF subjects before infection have not been reported, estimates from cell cultures (11) and sputum (12)(13)(14)(15)(16)(17)(18) suggest that CF mucus is at least three or four times more concentrated than normal. Therefore, mucus was obtained from well differentiated human airway cultures and was isotonically concentrated (1) to produce mucus of normal (2.5% solids wt/wt) and CF-like (8%) concentrations (Fig.…”

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confidence: 99%

A physical linkage between cystic fibrosis airway surface dehydration and Pseudomonas aeruginosa biofilms

Matsui¹,

Wagner

Hill³

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

217

228

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A vexing problem in cystic fibrosis (CF) pathogenesis has been to explain the high prevalence of Pseudomonas aeruginosa biofilms in CF airways. We speculated that airway surface liquid (ASL) hyperabsorption generates a concentrated airway mucus that interacts with P. aeruginosa to promote biofilms. To model CF vs. normal airway infections, normal (2.5% solids) and CF-like concentrated (8% solids) mucus were prepared, placed in flat chambers, and infected with an Ϸ5 ؋ 10 3 strain PAO1 P. aeruginosa. Although bacteria grew to 10 10 cfu/ml in both mucus concentrations, macrocolony formation was detected only in the CF-like (8% solids) mucus. Biophysical and functional measurements revealed that concentrated mucus exhibited properties that restrict bacterial motility and small molecule diffusion, resulting in high local bacterial densities with high autoinducer concentrations. These properties also rendered secondary forms of antimicrobial defense, e.g., lactoferrin, ineffective in preventing biofilm formation in a CF-like mucus environment. These data link airway surface liquid hyperabsorption to the high incidence of P. aeruginosa biofilms in CF via changes in the hydration-dependent physical-chemical properties of mucus and suggest that the thickened mucus gel model will be useful to develop therapies of P. aeruginosa biofilms in CF airways.mucus ͉ rheology C ystic fibrosis (CF) lung disease reflects the chronic bacterial infection of intrapulmonary airways with Pseudomonas aeruginosa biofilms (1, 2). P. aeruginosa biofilms have mostly been studied in flow chambers (3-7) that are good models for the biofilms that form on venous or urethral catheters under conditions of high flow rates and relatively high oxygen tensions. However, biofilms in CF airways form in thickened (concentrated) mucus gels that are relatively hypoxic and adherent to airway surfaces (see Fig. 1A) (8, 9). Recently, Sriramulu et al. (10) investigated the role autoregulators and amino acids play in the tightness of biofilm formation in a mucus stimulant of constant hydration. For the present study, we designed a culture system to investigate whether dehydration of the CF mucus environment may predispose to P. aeruginosa biofilm formation.A key aspect of the model was the selection of mucus concentrations that mimic normal and CF mucus. Although measurements of mucus concentration, i.e., the percentage of solids content, from CF subjects before infection have not been reported, estimates from cell cultures (11) and sputum (12-18) suggest that CF mucus is at least three or four times more concentrated than normal. Therefore, mucus was obtained from well differentiated human airway cultures and was isotonically concentrated (1) to produce mucus of normal (2.5% solids wt/wt) and CF-like (8%) concentrations (Fig. 1B). Aliquots of each were deposited in (i) an open chamber to model a mucus plaque adherent to CF airway surfaces with a residual lumen allowing airflow and (ii) a closed chamber to mimic a mucus plug occluding a CF airway (Fig. 1 A). P....

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“…To observe invasion of normal welldifferentiated airway epithelial cells, however, required a much higher infection dose of B. cepacia complex (41). Chronically infected and inflamed CF airway epithelium in vivo differs from normal epithelium in showing goblet cell hyperplasia, dehydrated and highly viscoelastic mucus which is adherent to the apical surface, impaired mucociliary function, and inactivated or absent antimicrobial factors in the apical mucus layer (1,3,8,16,29,43,48). Some of these changes, such as goblet cell hyperplasia, viscous mucus plugs obstructing the airways, and impaired mucociliary function, have also been reported in the lungs of uninfected fetuses with CF, indicating that pathological changes can occur prior to infection (8).…”

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Responses of Well-Differentiated Airway Epithelial Cell Cultures from Healthy Donors and Patients with Cystic Fibrosis to Burkholderia cenocepacia Infection

2004

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Well-differentiated cultures established from airway epithelia of patients with cystic fibrosis (CF cultures) exhibited goblet cell hyperplasia, increased secretion of mucus, and higher basal levels of interleukin-8 than similarly cultured cells from healthy donors. Upon apical infection with low doses (10 4 to 10 5 CFU) of Burkholderia cenocepacia isolate BC7, the two cultures gave different responses. While normal cultures trapped the added bacteria in the mucus layer, killed and/or inhibited bacterial replication, and prevented bacterial invasion of the cells, CF cultures failed to kill and/or supported the growth of bacteria, leading to invasion of underlying epithelial cells, compromised transepithelial permeability, and cell damage. Depletion of the surface mucus layer prior to bacterial infection rendered the normal cultures susceptible to bacterial invasion, but the invading bacteria were mainly confined to vacuoles within the cells and appeared to be nonviable. In contrast, bacteria that invaded cells in CF cultures were found free in the cytoplasm surrounded by intermediate filaments and also between cells. Cultured CF airway epithelium was therefore more susceptible to infection than normal epithelium. This mimics CF tissue in vivo and illustrates differences in the way epithelia in CF patients and normal subjects handle bacterial infection. In addition, we found that the CF and normal cell cultures responded differently not only to isolate BC7 but also to isolates of other B. cepacia complex species. We therefore conclude that this cell culture model is suitable for investigation of B. cepacia complex pathogenesis in CF patients.

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Mucus and Airway Epithelium Alterations in Cystic Fibrosis

Cited by 5 publications

References 79 publications

Reduced Three-Dimensional Motility in Dehydrated Airway Mucus Prevents Neutrophil Capture and Killing Bacteria on Airway Epithelial Surfaces

Reduced Three-Dimensional Motility in Dehydrated Airway Mucus Prevents Neutrophil Capture and Killing Bacteria on Airway Epithelial Surfaces

A physical linkage between cystic fibrosis airway surface dehydration and Pseudomonas aeruginosa biofilms

Responses of Well-Differentiated Airway Epithelial Cell Cultures from Healthy Donors and Patients with Cystic Fibrosis to Burkholderia cenocepacia Infection

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