TY - JOUR T1 - Physiological and Immunological Effects of Naïve and Pre-Activated Mesenchymal Stromal Cells in Klebsiella Pneumoniae-Induced Sepsis in Rats JF - European Respiratory Journal JO - Eur Respir J DO - 10.1183/13993003.congress-2020.2578 VL - 56 IS - suppl 64 SP - 2578 AU - Claire Masterson AU - Declan Byrnes AU - Hector Gonzalez AU - Daniel O'Toole AU - Sean Mccarthy AU - Shahd Horie AU - Jack Brady AU - John Laffey Y1 - 2020/09/07 UR - http://erj.ersjournals.com/content/56/suppl_64/2578.abstract N2 - Introduction: Bacterial infection remains the leading cause of ARDS development and death in critically ill patients. Klebsiella pneumoniae is a major cause of nosocomial and community-acquired infections globally [Moradigaravand et al., 2017]. Here we aimed to show that in a clinically relevant model of K. pneumoniae infection MSCs can attenuate multiple aspects of the injury.Methods: Sprague Dawley rats received an intratracheal bolus of K.pneumoniae to induce pulmonary sepsis. MSCs (naïve or pre-activated) were given intravenously and 48h later animals were assessed for injury/repair. Compliance and blood gas analyses were carried out pre-mortem. Blood, bronchoalveolar (BAL) and peritoneal lavage (PL) fluids were collected and analysed for leukocyte numbers, differential cell counts, bacterial content, and phagocytic function, while inflammatory cytokine levels were quantified by ELISA.Results: MSC administration resulted in the decrease of total BAL and PL cell infiltrates, the proportion of inflammatory cells, and K.pneumoniae bacterial load. MSC therapy also resulted in an improvement in alveolar–arterial gradient and serum lactate, but not in lung compliance.Conclusion: MSCs are effective in K.Pneumoniae-induced sepsis, reducing lung injury and bacterial load. Their mechanism of action is largely immunological and may be enhanced by pre-activation strategies. FootnotesCite this article as: European Respiratory Journal 2020; 56: Suppl. 64, 2578.This abstract was presented at the 2020 ERS International Congress, in session “Respiratory viruses in the "pre COVID-19" era”.This is an ERS International Congress abstract. No full-text version is available. Further material to accompany this abstract may be available at www.ers-education.org (ERS member access only). ER -