Pathological Myeloid Activation After Sepsis and Trauma Subtitle: Dysfunctional Myelopoiesis and Myeloid-Derived Suppressor Cells in Sepsis Pathobiology

Severe trauma is linked with challenging clinical trajectories as well as dismal long-term outcomes following hospital discharge. In surgical intensive care units, an alarming percentage of trauma patients can develop chronic critical illness (CCI), a prolonged acute-care and chronic-care hospitalization with unresolved organ dysfunction. CCI frequently manifests as a persistent inflammation, immunosuppression and catabolism syndrome (PICS). Trauma survivors suffering from PICS have repeat infections, poor cognitive performance, physical dysfunction and self-reported poor quality of life. These conditions, at least in part, are due to an unresolving pathologic myelopoiesis and ensuing prevalence of distinct myeloid-derived suppressor cells (MDSCs). The investigator's laboratory has also discovered key distinctions in these MDSCs' accompanying pathologic myeloid activation, while concurrently, they produce inflammatory cytokines, reactive nitric oxide (NO), oxidation and peroxidation products that damage parenchymal cells and promote inflammation. In addition, there are hematopoietic stem and progenitor cells (HSPCs), from which these white blood cells are derived, in the bone marrow and blood that contribute to the development of these dysfunctional cells. The investigators hypothesize that epigenetic alterations and immunometabolism affect each other in relation to the development and suppressive activity of these MDSCs. The overarching goal is to build upon this foundation and expand our understanding of the patient immune response to trauma. The investigator's goal is to define the key aspects of MDSC and HSPC pathophysiology that engender and maintain pathologic myeloid activation and its pathology after trauma and subsequently modify these systems to mitigate or prevent chronic critical illness and persistent inflammation, immunosuppression and catabolism syndrome. Identification is done through direct data collection from participants and collection of blood over a 6 month period and a one-time bone marrow collection at time of trauma surgery repair and elective hip repair.