ABSTRACT Objective Aspiration pneumonia is a major cause of morbidity and mortality in adults with swallowing impairment. Exosomes from mesenchymal stromal cells (MSCs) present a potential therapeutic for aspiration pneumonia. This study aimed to assess the potential of MSC exosomes to mitigate lung inflammation in a murine aspiration model. Methods Seventeen adult male rats were divided into three groups: Animals in the LPS‐EXO group ( n = 7) underwent intratracheal instillation of 2.5 mg/kg lipopolysaccharide (LPS) aspirate and 40 μL of MSC exosome therapeutic intravenously. The LPS‐only group ( n = 7) underwent LPS aspiration alone without exosome therapy. Three rats underwent instillation of air as sham controls. All animals were euthanized 6 h post instillation. Histopathologic lung injury severity was determined and gene expression of pro and anti‐inflammatory cytokines was evaluated using quantitative real‐time reverse transcription‐polymerase chain reaction (qRT‐PCR). Results The mean composite histologic lung injury score was 8.3 (±1.1) for the LPS‐only group, 7.13 (±3.2) for the LPS‐EXO treatment group, and 3.3 (±1.1) for the sham control group. One‐way ANOVA showed a significant group effect ( p = 0.02), and trend analysis revealed a significant linear improvement across groups ( p = 0.006; η 2 = 0.43). qRT‐PCR showed significantly lower Tnf expression in the LPS‐EXO group versus the LPS‐only group ( p < 0.05). No other significant differences were found between the LPS‐EXO and LPS‐only groups on qRT‐PCR. Conclusions Results of this preliminary investigation suggest that intravenous delivery of MSC exosomes reduces expression levels of proinflammatory cytokine Tnf and attenuates histopathological markers of lung injury in a murine model of aspiration‐induced lung damage. Level of Evidence NA.
Nativ‐Zeltzer et al. (Mon,) studied this question.