The ex-vivo perfused human lung is resistant to injury by high-dose s. pneumoniae bacteremia.

THE EX-VIVO PERFUSED HUMAN LUNG IS RESISTANT TO INJURY BY HIGH-DOSE S. PNEUMONIAE BACTEREMIA. Am J Physiol Lung Cell Mol Physiol. 2020 Jun 10;: Authors: Ross JT, Nesseler N, Leligdowicz A, Zemans RL, Mahida RY, Minus E, Langelier C, Gotts JE, Matthay MA Abstract Few patients with bacteremia from a non-pulmonary source develop ARDS. However, the mechanisms that protect the lung from injury in bacteremia have not been identified. We simulated bacteremia by adding S. pneumoniae to the perfusate of the ex vivo perfused human lung model. In contrast to a pneumonia model in which bacteria were instilled into the distal air spaces of one lobe, injection of high doses of S. pneumoniae into the perfusate was not associated with alveolar epithelial injury as demonstrated by low protein permeability of the alveolar epithelium, intact alveolar fluid clearance, and the absence of alveolar edema. Unexpectedly, the ex vivo human lung rapidly cleared large quantities of S. pneumoniae even though the perfusate had very few intravascular phagocytes and lacked immunoglobulins or complement. The bacteria were cleared in part by the small number of neutrophils in the perfusate, alveolar macrophages in the airspaces, and probably by interstitial pathways. Together, these findings identify one mechanism by which the lung and the alveolar epithelium are protected from injury in bacteremia. PMID: 32519893 [PubMed - as supplied by publisher]
Source: American Journal of Physiology. Lung Cellular and Molecular Physiology - Category: Cytology Authors: Tags: Am J Physiol Lung Cell Mol Physiol Source Type: research