Sodium transport and fluid balance in lungs from normal and dystrophic hamsters

Gravimetric and sodium transport characteristics of lungs from BIO 14.6 (dystrophic) hamsters were compared with those of lungs from golden Syrian (normal) hamsters at 30 and 150 days of age. Isolated perfused lungs were used to determine lung permeability and fluid balance differences between normal and dystrophic animals at both ages. Apparent permeability-surface area products for air space-to-vascular space sodium, sucrose, and fluorescein isothiocyanate-labeled dextran fluxes were compared in the four groups of hamsters. Morphometric analysis of fixed lungs of representative hamsters from each group was also performed. Dystrophic hamsters exhibited higher lung wet-to-dry weight ratios than normal hamsters at both ages. Lungs from dystrophic hamsters were less sensitive to inhibition of sodium transport by amiloride than lungs from age-matched normal hamsters. Dystrophic hamster lungs had higher absolute permeabilities of the passively transported solutes, lower permeability values for sodium, and only one-half of the amiloride-sensitive sodium transport of lungs from age-matched normal hamsters. Differences in lung fluid balance between dystrophic and normal hamsters may be related to differences in sodium clearance.

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Differences in sodium and D-glucose transport between hamster and rat lungs

Journal of Applied Physiology ◽

10.1152/jappl.1994.76.6.2578 ◽

1994 ◽

Vol 76 (6) ◽

pp. 2578-2585 ◽

Cited By ~ 9

Author(s):

B. E. Goodman ◽

J. L. Anderson ◽

J. W. Clemens ◽

K. J. Kircher ◽

M. L. Stormo ◽

...

Keyword(s):

Glucose Transport ◽

Sodium Transport ◽

Species Differences ◽

Fluorescein Isothiocyanate ◽

Transport Processes ◽

Apparent Permeability ◽

Gas Barrier ◽

Transport Inhibitor ◽

Rat Lungs ◽

Permeability Surface

The purpose of this study was to characterize phloridzin- and amiloride-sensitive transport across blood-gas barrier of hamster and rat lungs. Air spaces of isolated perfused lungs were instilled with a solution containing 22Na or L-[3H]glucose, D-[14C]glucose, and fluorescein isothiocyanate-labeled dextran. Apparent permeability-surface area products (PS) were calculated. Phloridzin (Na(+)-dependent D-glucose transport inhibitor) had no effect on D-glucose or sodium transport out of air spaces in hamster lungs. In contrast, in rat lungs, phloridzin decreased PS for D-glucose by 89% and that for Na by 28%. Trapping of 14CO2 in vascular samples was measured to estimate metabolism. Unlabeled air space D-glucose increased appearance of perfused D-[14C]glucose in air spaces of rat lungs. We conclude that Na(+)-dependent D-glucose transport is important for D-glucose uptake in rat lungs but not in hamster lungs. In hamster lungs, amiloride (Na+ transport inhibitor) also decreased PS for sodium, but drugs known to stimulate sodium transport in rat lungs had no effect. Thus, species differences in active transport processes exist in the distal air spaces of mammalian lungs.

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Pulmonary Interstitial Matrix and Lung Fluid Balance From Normal to the Acutely Injured Lung

Frontiers in Physiology ◽

10.3389/fphys.2021.781874 ◽

2021 ◽

Vol 12 ◽

Author(s):

Egidio Beretta ◽

Francesco Romanò ◽

Giulio Sancini ◽

James B. Grotberg ◽

Gary F. Nieman ◽

...

Keyword(s):

Fluid Balance ◽

Dry Weight ◽

Inflammatory Factors ◽

Pressure Gradients ◽

Lung Water ◽

Edema Formation ◽

Water Binding ◽

Lung Fluid ◽

Lung Fluid Balance ◽

Lung Overdistension

This review analyses the mechanisms by which lung fluid balance is strictly controlled in the air-blood barrier (ABB). Relatively large trans-endothelial and trans-epithelial Starling pressure gradients result in a minimal flow across the ABB thanks to low microvascular permeability aided by the macromolecular structure of the interstitial matrix. These edema safety factors are lost when the integrity of the interstitial matrix is damaged. The result is that small Starling pressure gradients, acting on a progressively expanding alveolar barrier with high permeability, generate a high transvascular flow that causes alveolar flooding in minutes. We modeled the trans-endothelial and trans-epithelial Starling pressure gradients under control conditions, as well as under increasing alveolar pressure (Palv) conditions of up to 25 cmH2O. We referred to the wet-to-dry weight (W/D) ratio, a specific index of lung water balance, to be correlated with the functional state of the interstitial structure. W/D averages ∼5 in control and might increase by up to ∼9 in severe edema, corresponding to ∼70% loss in the integrity of the native matrix. Factors buffering edemagenic conditions include: (i) an interstitial capacity for fluid accumulation located in the thick portion of ABB, (ii) the increase in interstitial pressure due to water binding by hyaluronan (the “safety factor” opposing the filtration gradient), and (iii) increased lymphatic flow. Inflammatory factors causing lung tissue damage include those of bacterial/viral and those of sterile nature. Production of reactive oxygen species (ROS) during hypoxia or hyperoxia, or excessive parenchymal stress/strain [lung overdistension caused by patient self-induced lung injury (P-SILI)] can all cause excessive inflammation. We discuss the heterogeneity of intrapulmonary distribution of W/D ratios. A W/D ∼6.5 has been identified as being critical for the transition to severe edema formation. Increasing Palv for W/D > 6.5, both trans-endothelial and trans-epithelial gradients favor filtration leading to alveolar flooding. Neither CT scan nor ultrasound can identify this initial level of lung fluid balance perturbation. A suggestion is put forward to identify a non-invasive tool to detect the earliest stages of perturbation of lung fluid balance before the condition becomes life-threatening.

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Faculty Opinions recommendation of Nadph oxidase regulates alveolar epithelial sodium channel activity and lung fluid balance in vivo via O⁻₂ signaling.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.13996979.15453086 ◽

2012 ◽

Author(s):

Kenneth Hallows ◽

Mohammad Al-bataineh

Keyword(s):

Nadph Oxidase ◽

Sodium Channel ◽

Fluid Balance ◽

Epithelial Sodium Channel ◽

Channel Activity ◽

Alveolar Epithelial ◽

Lung Fluid ◽

Lung Fluid Balance

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Lung fluid balance in patients with heart failure: effect of beta‐2 adrenergic‐receptor stimulation

The FASEB Journal ◽

10.1096/fasebj.25.1_supplement.1045.5 ◽

2011 ◽

Vol 25 (S1) ◽

Author(s):

Bryan Taylor ◽

Maile Ceridon ◽

Eric Snyder ◽

Alex Carlson ◽

Minelle Hulsebus ◽

...

Keyword(s):

Heart Failure ◽

Fluid Balance ◽

Adrenergic Receptor ◽

Receptor Stimulation ◽

Lung Fluid ◽

Lung Fluid Balance ◽

Patients With Heart Failure ◽

Beta 2

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Effect of endotoxin on lung fluid balance in unanesthetized sheep

Journal of Applied Physiology ◽

10.1152/jappl.1984.56.2.489 ◽

1984 ◽

Vol 56 (2) ◽

pp. 489-494 ◽

Cited By ~ 21

Author(s):

J. C. Gabel ◽

T. N. Hansen ◽

R. E. Drake

Keyword(s):

Left Atrial ◽

Capillary Permeability ◽

Dry Weight ◽

Base Line ◽

Lung Fluid ◽

Modified Method ◽

Lung Fluid Balance ◽

Extravascular Fluid ◽

Pulmonary Capillary ◽

Four Levels

We used a gravimetric technique to test for increased pulmonary capillary permeability after Escherichia coli endotoxin infusion in unanesthetized sheep. The sheep were chronically prepared with cannulas placed into the left atrium and pulmonary artery 1–2 wk before the experiments. We estimated pulmonary capillary pressure (Pc) as the average of pulmonary arterial and left atrial pressures, and used the modified method of Pierce to estimate the ratio of extravascular fluid weight (EVF) to blood-free dry weight. In 15 sheep we inflated a left atrial balloon to raise Pc to -10.7, 5, 10, or 15 mmHg above plasma oncotic pressure (IIc) for 3 h, then measured EVF. EVF averaged 4.0 +/- 0.2 (base line), 4.3 +/- 0.1, 4.5 +/- 0.1, and 5.1 +/- 0.5 (SD), respectively, for the four levels of Pc - IIc. We gave seven additional sheep 1 microgram/kg of E. coli endotoxin (0127:B8) and measured EVF after 3 h of stable Pc. Endotoxin increased Pc in each sheep. EVF was higher than control for the endotoxin sheep with Pc - IIc greater than -1. This finding is consistent with an increase in pulmonary capillary permeability caused by endotoxin. However, EVF was not elevated in the endotoxin sheep with Pc - IIc less than 1 mmHg. This shows that the increased permeability was insufficient to cause edema unless Pc was elevated. Thus endotoxin may cause edema by two mechanisms, 1) an increase in capillary permeability, and 2) an increase in Pc.

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Inspiratory airway obstruction does not affect lung fluid balance in lambs

Journal of Applied Physiology ◽

10.1152/jappl.1985.58.4.1314 ◽

1985 ◽

Vol 58 (4) ◽

pp. 1314-1318 ◽

Cited By ~ 6

Author(s):

T. N. Hansen ◽

A. L. Gest ◽

S. Landers

Keyword(s):

Airway Obstruction ◽

Endotracheal Tube ◽

Fluid Balance ◽

Left Atrial ◽

Lymph Flow ◽

Lung Fluid ◽

Lung Fluid Balance ◽

Pulmonary Arterial ◽

Lung Lymph ◽

Lung Lymph Flow

The purpose of this study was to examine the effects of inspiratory airway obstruction on lung fluid balance in newborn lambs. We studied seven 2- to 4-wk-old lambs that were sedated with chloral hydrate and allowed to breathe 30–40% O2 spontaneously through an endotracheal tube. We measured lung lymph flow, lymph and plasma protein concentrations, pulmonary arterial and left atrial pressures, mean and phasic pleural pressures and airway pressures, and cardiac output during a 2-h base-line period and then during a 2- to 3-h period of inspiratory airway obstruction produced by partially occluding the inspiratory limb of a nonrebreathing valve attached to the endotracheal tube. During inspiratory airway obstruction, both pleural and airway pressures decreased 5 Torr, whereas pulmonary arterial and left atrial pressures each decreased 4 Torr. As a result, calculated filtration pressure remained unchanged. Inspiratory airway obstruction had no effect on steady-state lung lymph flow or the lymph protein concentration relative to that of plasma. We conclude that in the spontaneously breathing lamb, any decrease in interstitial pressure resulting from inspiratory airway obstruction is offset by a decrease in microvascular hydrostatic pressure so that net fluid filtration remains unchanged.

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