State of airway surface liquid on guinea pig trachea

1995 ◽  
Vol 78 (6) ◽  
pp. 2020-2024 ◽  
Author(s):  
H. Rahmoune ◽  
K. L. Shephard
Keyword(s):  
Relative Humidity ◽  
Guinea Pig ◽  
Osmotic Pressure ◽  
Potential Difference ◽  
Airway Surface Liquid ◽  
Transepithelial Potential Difference ◽  
Air Interface ◽  
Surface Liquid ◽  
Condense Water

Two preparations of the guinea pig trachea have been examined: an isolated preparation and a preparation in vivo, both exposed to air on the mucosal surface. Ion-selective microelectrodes have been used to measure Na (alpha Na) and K activities (alpha K) in airway surface liquid (ASL) while airflows tending either to evaporate or to condense water were applied. Other variables measured included ASL depth and transepithelial potential difference (TEPD). In isolated preparations, condensation did not progressively alter depth, alpha Na, or TEPD but caused a slight increase in alpha K. Evaporation decreased depth; increased alpha Na, alpha K, and osmotic pressure; and changed TEPD. Measurements on preparations in vivo broadly supported these observations. In addition, the depth of ASL developed on isolated preparations was related to the humidity of the air to which animals had been previously exposed. We conclude that condensation and evaporation at the ASL-air interface in isolated preparations and in preparations in vivo do significantly modify key ASL variables as does the relative humidity of the air to which animals are exposed before experimentation.

Evaporation-induced changes in airway surface liquid on an isolated guinea pig trachea

1994 ◽  
Vol 76 (3) ◽  
pp. 1156-1165 ◽  
Author(s):  
K. L. Shephard ◽  
H. Rahmoune
Keyword(s):  
Guinea Pig ◽  
Sodium Transport ◽  
Vapor Pressure Deficit ◽  
Sodium Concentration ◽  
Sodium Content ◽  
Airway Surface Liquid ◽  
Sodium Activity ◽  
Surface Liquid ◽  
Induced Changes

An isolated preparation of the guinea pig trachea was developed. The trachea was exposed serosally to Krebs-Henseleit solution and mucosally to tidal airflow, designed to mimic conditions in vivo. The preparation establishes stable layers of airway surface liquid (ASL). Typical depth, transepithelial potential differences, and sodium activity are 200 microns, -3 mV, and 125 mM, respectively (approximate sodium concn 170 mM). When exposed to air with a vapor pressure deficit (VPD), evaporation of water occurs from ASL, ASL depth decreases, and the concentration of sodium ions in ASL increases. The water content of air passing over the trachea also increases. This measurement is compared with measurements of the change in volume of ASL, based on depth changes, to yield estimates of net water transport (NWT). Measurements of changes in the sodium content of ASL allow for the calculation of net sodium transport by the trachea. Evaporation rate, changes in the volume of ASL, NWT, and net sodium transport are all influenced by VPD. The results suggest that evaporation from ASL increases its sodium concentration (and osmotic pressure) and increases osmotically driven NWT to replace water lost. Evaporation-induced increases in the sodium concentration appear to be limited by enhanced sodium uptake at high VPD.

Airway surface liquid thickness as a function of lung volume in small airways of the guinea pig

1994 ◽  
Vol 77 (5) ◽  
pp. 2333-2340 ◽  
Author(s):  
D. Yager ◽  
T. Cloutier ◽  
H. Feldman ◽  
J. Bastacky ◽  
J. M. Drazen ◽  
...  
Keyword(s):  
Surface Tension ◽  
Epithelial Cells ◽  
Guinea Pig ◽  
Cross Sections ◽  
Lung Volume ◽  
Longitudinal Direction ◽  
Small Airways ◽  
Airway Surface Liquid ◽  
Residual Capacity ◽  
Surface Liquid

The average thickness and distribution of airway surface liquid (ASL) on the luminal surface of peripheral airways were measured in normal guinea pig lungs frozen at functional residual capacity (FRC) and total lung capacity (TLC). Tissue blocks containing cross sections of airways of internal perimeter 0.188–3.342 mm were cut from frozen lungs and imaged by low-temperature scanning electron microscopy (LTSEM). Measurements made from LTSEM images were found to be independent of freezing rate by comparison of measurements at rapid and slow freezing rates. At both lung volumes, the ASL was not uniformly distributed in either the circumferential or longitudinal direction; there were regions of ASL where its thickness was < 0.1 micron, whereas in other regions ASL collected in pools. Discernible liquid on the surfaces of airways frozen at FRC followed the contours of epithelial cells and collected in pockets formed by neighboring cells, a geometry consistent with a low value of surface tension at the air-liquid interface. At TLC airway liquid collected to cover epithelial cells and to form a liquid meniscus, a geometry consistent with a higher value of surface tension. The average ASL thickness (h) was approximately proportional to the square root of airway internal perimeter, regardless of lung volume. For airways of internal perimeter 250 and 1,800 microns, h was 0.9 and 1.8 microns at FRC and 1.7 and 3.7 microns at TLC, respectively. For a given airway internal perimeter, h was 1.99 times thicker at TLC than at FRC; the difference was statistically significant (P < 0.01; 95% confidence interval 1.29–3.08).(ABSTRACT TRUNCATED AT 250 WORDS)

Calcium secretion in canine tracheal mucosa

1985 ◽  
Vol 59 (4) ◽  
pp. 1191-1195 ◽  
Author(s):  
F. J. Al-Bazzaz ◽  
T. Jayaram
Keyword(s):  
Short Circuit ◽  
Short Circuit Current ◽  
Open Circuit ◽  
Potential Difference ◽  
Secretory Process ◽  
Metabolic Inhibitor ◽  
Tracheal Mucosa ◽  
Transepithelial Potential ◽  
Transepithelial Potential Difference

Calcium (Ca) affects many cellular functions of the respiratory tract mucosa and might alter the viscoelastic properties of mucus. To evaluate Ca homeostasis in a respiratory epithelium we investigated transport of Ca by the canine tracheal mucosa. Mucosal tissues were mounted in Ussing-type chambers and bathed with Krebs-Henseleit solution at 37 degrees C. Unidirectional fluxes of 45Ca were determined in tissues that were matched by conductance and short-circuit current (SCC). Under short-circuit conditions there was a significant net Ca secretion of 1.82 +/- 0.36 neq . cm-2 . h-1 (mean +/- SE). Under open-circuit conditions, where the spontaneous transepithelial potential difference could attract Ca toward the lumen, net Ca secretion increased significantly to 4.40 +/- 1.14 compared with 1.54 +/- 1.17 neq . cm-2 . h-1 when the preparation was short-circuited. Addition of a metabolic inhibitor, 2,4-dinitrophenol (2 mM in the mucosal bath), decreased tissue conductance and SCC and slightly decreased the unidirectional movement of Ca from submucosa to lumen. Submucosal epinephrine (10 microM) significantly enhanced Ca secretion by 2.0 +/- 0.63 neq . cm-2 . h-1. Submucosal ouabain (0.1 mM) failed to inhibit Ca secretion. The data suggest that canine tracheal mucosa secretes Ca; this secretory process is augmented by epinephrine or by the presence of a transepithelial potential difference as found under in vivo conditions.

Regulation of Airway Surface Liquid on the Isolated Guinea-pig Trachea

1994 ◽  
Vol 7 (4) ◽  
pp. 265-269 ◽  
Author(s):  
H. Rahmoune ◽  
K.L. Shephard
Keyword(s):  
Guinea Pig ◽  
Airway Surface Liquid ◽  
Surface Liquid

scholarly journals Parallel effects of VX-770 on transepithelial potential difference in vitro and in vivo

2010 ◽  
Vol 9 ◽  
pp. S20 ◽  
Author(s):  
S.M. Rowe ◽  
J.P. Clancy ◽  
M. Boyle ◽  
F. Van Goor ◽  
C. Ordonez ◽  
...  
Keyword(s):  
Potential Difference ◽  
Transepithelial Potential ◽  
Transepithelial Potential Difference

scholarly journals Transepithelial potential difference of the intestine and gallbladder of Hoplias malabaricus, a freshwater teleost. effect of urotensins I and II

1996 ◽  
Vol 18 (18) ◽  
pp. 83 ◽  
Author(s):  
Maria Amália Pavanato ◽  
Bernardo Baldisserotto ◽  
Roni João Rakoski ◽  
Olga Martins Mimura
Keyword(s):  
Potential Difference ◽  
Freshwater Teleost ◽  
Hoplias Malabaricus ◽  
Transepithelial Potential ◽  
Transepithelial Potential Difference ◽  
Transport Of Ions ◽  
In The Beginning ◽  
Stabilization Period

This study analyzed the effect of the injection of urotensin I (UI) and urotensis II (UII) on the stabilization of the transepithelial potential difference (TPD) of the medium intestine, rectum, and gallbladder of Hoplias malabaricus to investigate if the transport of ions in these organs is affected "in vivo" by these neurohormones. The TPD of the medium intestine, rectum and gallbladder was serosa positive, and remained constant since the first measurement. The injection of both urotensins did not alter the stabilization of the TPD of the medium intestine and rectum when compared with saline-injected group. The injection of UI increased the TPD of the gallbladder in the beginning (0-10 min) of the stabilization period and in the interval of 20-30 min of the stabilization period when fishes were killed 2h and 4h after the injection, respectively, in relation to saline-injected group. The UII injection increased the TPD of the gallbladder only in the beginning (time 0) of the stabilization period in relation to saline when fishes were killed 2h after the injection. No changes in the TPD of the studied organs were detected when fishes were killed 4h after the injection of UII. This study confirms the hypothesis that UI and UII can participate in the regulation of the composition of the bile of fishes, since the injection of both hormones altered the TPD of the gallbladder of H. malabaricus.

In Vivo Measurements of the Transepithelial Potential Difference in Normal and Homografted Tracheas.

2002 ◽  
Vol 53 (4) ◽  
pp. 343-347
Author(s):  
Shuichiro Hayashi ◽  
Haruna Nakaseko ◽  
Tianqun Yang ◽  
Kazuhiko Takeuchi ◽  
Yuichi Majima
Keyword(s):  
Potential Difference ◽  
Transepithelial Potential ◽  
Transepithelial Potential Difference ◽  
In Vivo Measurements

scholarly journals Engineered mutant α-ENaC subunit mRNA delivered by lipid nanoparticles reduces amiloride currents in cystic fibrosis–based cell and mice models

2020 ◽  
Vol 6 (47) ◽  
pp. eabc5911
Author(s):  
Anindit Mukherjee ◽  
Kelvin D. MacDonald ◽  
Jeonghwan Kim ◽  
Michael I. Henderson ◽  
Yulia Eygeris ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Therapeutic Potential ◽  
Lipid Nanoparticles ◽  
Sodium Absorption ◽  
Airway Surface Liquid ◽  
Surface Liquid ◽  
Cf Transmembrane Conductance Regulator ◽  
Airway Cells

Cystic fibrosis (CF) results from mutations in the chloride-conducting CF transmembrane conductance regulator (CFTR) gene. Airway dehydration and impaired mucociliary clearance in CF is proposed to result in tonic epithelial sodium channel (ENaC) activity, which drives amiloride-sensitive electrogenic sodium absorption. Decreasing sodium absorption by inhibiting ENaC can reverse airway surface liquid dehydration. Here, we inhibit endogenous heterotrimeric ENaC channels by introducing inactivating mutant ENaC α mRNA (αmutENaC). Lipid nanoparticles carrying αmutENaC were transfected in CF-based airway cells in vitro and in vivo. We observed a significant decrease in macroscopic as well as amiloride-sensitive ENaC currents and an increase in airway surface liquid height in CF airway cells. Similarly, intranasal transfection of αmutENaC mRNA decreased amiloride-sensitive nasal potential difference in CFTRKO mice. These data suggest that mRNA-based ENaC inhibition is a powerful strategy for reducing mucus dehydration and has therapeutic potential for treating CF in all patients, independent of genotype.

scholarly journals Culture with apically applied healthy or disease sputum alters the airway surface liquid proteome and ion transport across human bronchial epithelial cells.

2021 ◽  
Author(s):  
Maximillian Woodall ◽  
Boris Reidel ◽  
Mehmet Kesimer ◽  
Robert Tarran ◽  
Deborah L Baines
Keyword(s):  
Epithelial Cells ◽  
Ion Transport ◽  
Short Circuit ◽  
Bronchial Epithelial Cells ◽  
Airway Surface Liquid ◽  
Human Bronchial Epithelial Cells ◽  
Bronchial Epithelial ◽  
Surface Liquid

Airway secretions contain many signalling molecules and peptides/proteins that are not found in airway surface liquid (ASL) generated by normal human bronchial epithelial cells (NHBE) in vitro. These play a key role in innate defence and mediate communication between the epithelium, immune cells and the external environment. We investigated how culture of NHBE with apically applied secretions from healthy or disease (Cystic Fibrosis, CF) lungs affected epithelial function with a view to providing better in vitro models of the in vivo environment. NHBE from 6-8 different donors were cultured at air-liquid interface (ALI), with apically applied sputum from normal healthy donors (NLS) or CF donors (CFS) for 2-4 hours, 48 hours or with sputum reapplied over 48 hours. Proteomic analysis was carried out on the sputa and on NHBE ASL before and after culture with sputa. Transepithelial electrical resistance (TEER), short circuit current (Isc) and changes to ASL height were measured. There were 71 proteins common to both sputa but not ASL. The protease:protease inhibitor balance was increased in CFS compared to NLS and ASL. Culture of NHBE with sputa for 48 hours identified additional factors not present in NLS, CFS or ASL alone. Culture with either NLS or CFS for 48 hours increased CFTR activity, calcium activated chloride channel (CaCC) activity and changed ASL height. These data indicate that culture with healthy or disease sputum changes the proteomic profile of ASL and ion transport properties of NHBE and this may increase physiological relevance when using in vitro airway models.

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