The ex vivo perfused human lung is resistant to injury by high-dose S. pneumoniae bacteremia.
Am J Physiol Lung Cell Mol Physiol
; 319(2): L218-L227, 2020 08 01.
Article
in En
| MEDLINE
| ID: mdl-32519893
ABSTRACT
Few patients with bacteremia from a nonpulmonary source develop acute respiratory distress syndrome (ARDS). However, the mechanisms that protect the lung from injury in bacteremia have not been identified. We simulated bacteremia by adding Streptococcus 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.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Streptococcus pneumoniae
/
Bacteremia
/
Acute Lung Injury
/
Lung
Type of study:
Prognostic_studies
Limits:
Adult
/
Female
/
Humans
/
Male
/
Middle aged
Language:
En
Journal:
Am J Physiol Lung Cell Mol Physiol
Journal subject:
BIOLOGIA MOLECULAR
/
FISIOLOGIA
Year:
2020
Document type:
Article