The overall hypothesis of this program is that persistent inflammation, immunosuppression and catabolism (PICS) are the hallmarks of pathophysiologic processes leading to decreases in long-term survival and functional capacity in patients with chronic critical illness (CCI). While persistent expansion of myeloid-derived suppressor cells (MDSC;Project #2) is a key underlying mechanism of immunosuppression and inflammation in CCI, this project investigates the mechanism by which kidney damage in sepsis initiates an anti-angiogenic state that augments and perpetuates inflammation, immunosuppression, and catabolism in CCI. During sepsis, infection, via toll-like receptors, and hypoxia leads to activation of hypoxia inducible factor (HIF)-1 and subsequent upregulation of angiogenic factors (erythropoietin (EPO) and vascular endothelial growth factor (VEGF)). We have previously shown that the heterodimeric EPO receptor (consisting of the EPO receptor and ?-common receptor (?cR)) interacts with VEGF receptor 2 (VEGFR-2) to mobilize bone marrow derived angiogenic cells, which can contribute to the endothelial repair. EPO and VEGF can both initiate the anti- angiogenic response of upregulation of soluble VEGR-2 (sFlt-1) and angiopoietin-2 (ANG-2). While sFlt-1 binds VEGF reducing its circulating levels and counteracting its effect, unopposed EPO leads to persistent sFlt-1 and ANG-2 elevation and VEGF suppression. Our hypothesis, is that patients in whom kidney damage in sepsis results in an exaggerated EPO response, relative to VEGF, the stimulation of sFlt-1 leads to a persistence of an anti-angiogenic (low levels of VEGF and elevated ANG-2), inflammatory (elevated EPO) state. The investigators propose to examine kidney damage in septic patients as a predictor of anti-angiogenic imbalance and to determine whether anti-angiogenic balance is associated with increased expansion of MDSCs (as determined in Project #2) and increased likelihood of PICS, characterized by morbid long-term outcome (Project #1). The direct effect of increased EPO production on MDSC expansion will be tested in murine models of chronic sepsis using the ?cR knockout mouse.

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National Institute of General Medical Sciences (NIGMS)
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University of Florida
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Mira, Juan C; Brakenridge, Scott C; Moldawer, Lyle L et al. (2017) Persistent Inflammation, Immunosuppression and Catabolism Syndrome. Crit Care Clin 33:245-258
Alamo, Ines G; Kannan, Kolenkode B; Loftus, Tyler J et al. (2017) Severe trauma and chronic stress activates extramedullary erythropoiesis. J Trauma Acute Care Surg 83:144-150
Loftus, Tyler J; Raymond, Steven L; Sarosi Jr, George A et al. (2017) Predicting appendiceal tumors among patients with appendicitis. J Trauma Acute Care Surg 82:771-775
Mathias, Brittany; Delmas, Amber L; Ozrazgat-Baslanti, Tezcan et al. (2017) Human Myeloid-derived Suppressor Cells are Associated With Chronic Immune Suppression After Severe Sepsis/Septic Shock. Ann Surg 265:827-834
Mira, Juan C; Cuschieri, Joseph; Ozrazgat-Baslanti, Tezcan et al. (2017) The Epidemiology of Chronic Critical Illness After Severe Traumatic Injury at Two Level-One Trauma Centers. Crit Care Med 45:1989-1996
Loftus, Tyler J; Mira, Juan C; Ozrazgat-Baslanti, Tezcan et al. (2017) Sepsis and Critical Illness Research Center investigators: protocols and standard operating procedures for a prospective cohort study of sepsis in critically ill surgical patients. BMJ Open 7:e015136
Lysak, Nicholas; Bihorac, Azra; Hobson, Charles (2017) Mortality and cost of acute and chronic kidney disease after cardiac surgery. Curr Opin Anaesthesiol 30:113-117
Loftus, Tyler J; Jordan, Janeen R; Croft, Chasen A et al. (2017) Temporary abdominal closure for trauma and intra-abdominal sepsis: Different patients, different outcomes. J Trauma Acute Care Surg 82:345-350
Loftus, Tyler J; Brakenridge, Scott C; Dessaigne, Camille G et al. (2017) Antibiotics May be Safely Discontinued Within One Week of Percutaneous Cholecystostomy. World J Surg 41:1239-1245
Stortz, Julie A; Efron, Philip A (2017) Editorial: Myeloid-derived suppressor cells: a new therapeutic target in sepsis patients. J Leukoc Biol 102:185-187

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