Hypoxia-preconditioned mesenchymal stem cells ameliorate ischemia/reperfusion-induced lung injury

November Hypoxia-preconditioned mesenchymal stem cells ameliorate ischemia/reperfusion- induced lung injury Yung-Yang Liu 0 1 Chi-Huei Chiang 0 1 Shih-Chieh Hung 1 2 Chih-Feng Chian 1 Chen-Liang Tsai 1 Wei-Chih Chen 0 1 Haibo Zhang 1 0 Chest Department, Taipei Veterans General Hospital , Taipei, Taiwan , 2 Department of Medicine, School of Medicine, National Yang-Ming University , Taipei, Taiwan , 3 Institute of Clinical Medicine, School of Medicine, National Yang-Ming University , Taipei, Taiwan , 4 Department of Medicine, Tri-Service General Hospital, National Defense Medical Center , Taipei, Taiwan , 5 Integrative Stem Cell Center, Chinese Medical University Hospital, Graduate Institute of Clinical Medical Science, China Medical University , Taichung , Taiwan 1 Editor: Guo-Chang Fan, University of Cincinnati College of Medicine , UNITED STATES 2 Graduate Institute of Clinical Medical Science, China Medical University , Taichung, Taiwan , 7 Department of Orthopaedics & Traumatology, Taipei Veterans General Hospital , Taipei, Taiwan , 8 Therapeutical and Research Center of Musculoskeletal Tumor, Taipei Veterans General Hospital , Taipei, Taiwan , 9 Division of Pulmonary and Critical Care Medicine, Internal Medicine Department, Tri-Service General Hospital, National Defense Medical Center , Taipei, Taiwan , 10 Department of Physiology, and Interdepartmental Division of Critical Care Medicine, University of Toronto , Toronto, Ontario , Canada - Data Availability Statement: All relevant data are within the paper and its Supporting Information files. Background Hypoxia preconditioning has been proven to be an effective method to enhance the thera peutic action of mesenchymal stem cells (MSCs). However, the beneficial effects of hypoxic MSCs in ischemia/reperfusion (I/R) lung injury have yet to be investigated. In this study, we hypothesized that the administration of hypoxic MSCs would have a positive therapeutic impact on I/R lung injury at molecular, cellular, and functional levels. Methods Results I/R lung injury was induced in isolated and perfused rat lungs. Hypoxic MSCs were adminis tered in perfusate at a low (2.5×105 cells) and high (1×106 cells) dose. Rats ventilated with a low tidal volume of 6 ml/kg served as controls. Hemodynamics, lung injury indices, inflammatory responses and activation of apoptotic pathways were determined. I/R induced permeability pulmonary edema with capillary leakage and increased levels of reactive oxygen species (ROS), pro-inflammatory cytokines, adhesion molecules, cytosolic cytochrome C, and activated MAPK, NF-κB, and apoptotic pathways. The administration of a low dose of hypoxic MSCs effectively attenuated I/R pathologic lung injury score by inhibiting inflammatory responses associated with the generation of ROS and anti-apoptosis effect, however this effect was not observed with a high dose of hypoxic MSCs. Mechanistically, a low dose of hypoxic MSCs down-regulated P38 MAPK and NF-κB signaling but Competing interests: The authors have declared that no competing interests exist. Abbreviations: Bcl-2, B-cell lymphoma 2; ERK, extracellular signal-regulated kinases; ICAM-1, intercellular adhesion molecule 1; IL-1β, interleukin-1β; I/R, ischemia/reperfusion injury; JNK, Jun N-terminal kinases; Kfc, pulmonary capillary filtration coefficient; LWG, lung weight gain; MIP-2, macrophage inflammatory protein 2; MPO, myeloperoxidase; MSCs, mesenchymal stem cells; NF-kB, nuclear factor kappa-κB; Ppa, pulmonary arterial pressure; P38 MAPK, P38 mitogen-activated protein kinase; TNF-α, tumor necrosis factor-α; VCAM-1, vascular cell adhesion protein 1. upregulated glutathione, prostaglandin E2, IL-10, mitochondrial cytochrome C and Bcl-2. MSCs infused at a low dose migrated into interstitial and alveolar spaces and bronchial trees, while MSCs infused at a high dose aggregated in the microcirculation and induced pulmonary embolism. Conclusions Hypoxic MSCs can quickly migrate into extravascular lung tissue and adhere to other inflammatory or structure cells and attenuate I/R lung injury through anti-oxidant, anti-inflammatory and anti-apoptotic mechanisms. However, the dose of MSCs needs to be optimized to prevent pulmonary embolism and thrombosis. Introduction Ischemia/reperfusion (I/R) injury is a common clinical problem encountered in lung transplantation, resuscitation from shock and cardiac surgery. I/R injury following organ transplantation can result in primary graft dysfunction, and it is the leading cause of morbidity and mortality after transplantation [ 1 ]. Although the molecular events that occur during I/R lung injury are complex, we previously reported two major presentations of I/R lung injury in the early phase: permeability pulmonary edema and acute inflammation [ 2 ]. Previous studies have reported that microvascular injuries are evoked by activated endothelial cells and oxidative cell damage, and that a burst of oxidative stress plays an impo (...truncated)