Mechanisms of impaired alveolar fluid clearance

Abstract

Impaired alveolar fluid clearance (AFC) is an important cause of alveolar edema fluid accumulation in patients with acute respiratory distress syndrome (ARDS). Alveolar edema leads to insufficient gas exchange and worse clinical outcomes. Thus, it is important to understand the pathophysiology of impaired AFC in order to develop new therapies for ARDS. Over the last few decades, multiple experimental studies have been done to understand the molecular, cellular, and physiological mechanisms that regulate AFC in the normal and the injured lung. This review provides a review of AFC in the normal lung, focuses on the mechanisms of impaired AFC, and then outlines the regulation of AFC. Finally, we summarize ongoing challenges and possible future research that may offer promising therapies for ARDS.

PEBP4 deficiency aggravates LPS-induced acute lung injury and alveolar fluid clearance impairment via modulating PI3K/AKT signaling pathway

“…2 C-D). As previously mentioned, lung edema is the other central event of ALI [ 6 ]. During the process of ALI, the damage to the alveolar epithelial-endothelial barrier can result in pulmonary edema.…”

“…It is crucial for the prognosis of ALI to remove pulmonary edema fluid in a timely and effective manner and to improve the lung’s oxygenation ability [ 6 ]. Epithelial sodium channel (ENaC), a heterotetramer protein composed of two α subunits, one β subunit, and one γ subunit, plays a critical role in the process of alveolar fluid clearance (AFC) [ 7 ].…”

“…Generally, sodium ion in alveolar space is transported into AECs via ENaC located on the apical membrane of AECs, and then into the pulmonary interstitium with the help of Na,K-ATPase located on the basement membrane of AECs. During this process, sodium ion transportation across membrane creates an osmotic gradient that drives the reabsorption of edematous fluid from alveolar space into pulmonary interstitium, and then alleviates pulmonary edema through venous and lymphatic back-flow [ 6 ].…”

Biological effects of corticosteroids on pneumococcal pneumonia in Mice—translational significance

“…Alveolar Epithelium-Functional and Biochemical Studies. To test the effect of dexamethasone on the vectorial fluid clearance capacity of alveolar epithelium [26,27], we measured alveolar fluid clearance 36 h after infection (n = 9-14/group). Alveolar fluid clearance was substantially impaired with pneumococcal pneumonia, but there was no significant difference between the untreated and other treatment groups (Additional file 1: Fig.…”

Activating transcription factor 6 in the endothelial context

“…The pulmonary endothelial cells form a semipermeable monolayer to separate the blood from the interstitium, and synergize with alveoli epithelial cells to facilitate gas equilibration and diffusion [ 1 ]. Barrier dysfunction, which results to alveolar edema, is considered the hallmark of ARDS [ 2 ]. The mortality rate due to that syndrome can be as high as 46% in severe cases, and ARDS incidence ranges from 64.2 to 78.9 cases/100,000 person-years [ 3 ].…”