Patients who initially survive from traumatic thoracic injury are at risk for Acute Respiratory Distress Syndrome ARDS. The only proven treatments available once ARDS has developed are low tidal volume ventilation ARDSnet and proning, but there is no existing treatment strategy to prevent the onset of ARDS following traumatic injury. As a potential solution, recent evidence suggest that the therapeutic administration of mesenchymal stem cells MSCs can prevent ARDS secondary to medical causes, but this has not been investigated in the trauma setting. Therefore, the purpose of this project is to conduct a series of in vitro and in vivo studies to determine if the therapeutic administration of MSCs prevents the development of ARDS following pulmonary contusion and hemorrhagic shock. During Year 1, we obtained both IACUC and ACURO approval, and have completed our model development phase for the swine model. To improve the well-being of the animals and maintain consistency in the model, we redesigned the protocol to keep the swine sedated for 48 hours using a combined inhaled and IV anesthetic regimen. In addition, we successfully harvested MSCs from swine bone marrow and expanded the cells on the Quantum with greater than 80 percent viability. Future Quantum runs are scheduled to provide MSCs for the randomized study. Our plans for Year 2 include starting the randomized in vivo swine study, continue MSC cell expansion, and start the in vitro analysis of plasma, tissue and BAL samples from the study swine.