Delayed MSC therapy enhances resolution of organized pneumonia induced by antibiotic resistant Klebsiella pneumoniae infection

IntroductionMesenchymal stromal cells (MSC) are a promising therapeutic for pneumonia-induced sepsis. Here we sought to determine the efficacy of delayed administration of naive and activated bone marrow (BM), adipose (AD), and umbilical cord (UC) derived MSCs in organized antibiotic resistant Klebsiella pneumosepsis. MethodsHuman BM-, AD-, and UC-MSCs were isolated and expanded and used either in the naive state or following cytokine pre-activation. The effect of MSC tissue source and activation status was assessed first in vitro. Subsequent experiments assessed therapeutic potential as a delayed therapy at 48 h post infection of rodents with Klebsiella pneumoniae, with efficacy assessed at 120 h. ResultsBM-, AD-, and UC-MSCs accelerated epithelial healing, increased phagocytosis, and reduced ROS-induced epithelial injury in vitro, with AD-MSCs less effective, and naive MSCs more effective than pre-activated MSCs. Delayed MSC administration in pre-clinical organized Klebsiella pneumosepsis had no effect on physiologic indices, but enhanced resolution of structural lung injury. Delayed therapy with pre-activated MSCs reduced mRNA concentrations of fibrotic factors. Naive MSC treatment reduced key circulating cell proportions and increased bacterial killing capacity in the lungs whereas pre-activated MSCs enhanced the phagocytic index of pulmonary white cells. DiscussionDelayed MSC therapy enhanced resolution of lung injury induced by antibiotic resistant Klebsiella infection and favorably modulated immune cell profile. Overall, AD-MSCs were less effective than either UC- or BM-MSCs, while naive MSCs had a more favorable effect profile compared to pre-activated MSCs.

Automated summary

This study aimed to evaluate the efficacy of delayed administration of bone marrow (BM), adipose (AD), and umbilical cord (UC) derived mesenchymal stromal cells (MSC) in antibiotic resistant pneumonia-induced sepsis. In vitro experiments showed that BM-, AD-, and UC-MSCs accelerated epithelial healing, increased phagocytosis, and reduced epithelial injury. Delayed MSC therapy in pre-clinical sepsis enhanced resolution of lung injury and modulated immune cell profile. BM and UC-MSCs were more effective than AD-MSCs, and naive MSCs had a more favorable effect profile compared to pre-activated MSCs.