Autophagy after Exsanguination Cardiac Arrest and EPR

I am applying for a post-doctoral stay at the Safar Center for Resuscitation Research (SCRR), Pittsburgh, USA, to study Emergency Preservation and Resuscitation in animal experiments (a) and clinical practice (b). (a) Outcome after exsanguination cardiac arrest (CA) is dismal because of a volume-depleted and trauma-disrupted circulatory system. Emergency preservation and resuscitation (EPR) is preservation of the organism by rapid cooling with a cold saline aortic flush, followed by damage control surgery and delayed resuscitation using cardiopulmonary bypass (CPB). EPR has been shown to be feasible in numerous animal studies in dogs, swine and rats. I will work with the EPR-rat model established at the SCRR. Recently, a novel mechanism of neuronal death called "autophagy" has been identified as a possible target to improve outcome after CA. I have chosen to study autophagic neuronal death in the laboratory because it 1) represents a novel cell death pathway (in addition to necrosis and apoptosis), 2) has been shown by the investigative team at the SCRR to occur in human brain injury, 3) may represent a new therapeutic target, and 4) has not been explored in the setting of therapeutic hypothermia. The experiments adress the following questions: Does autophagy contribute to delayed neuronal death and cognitive deficits after CA, or alternatively, does autophagy have a homeostatic role? Can functional outcome be improved by the application of two drugs (?-glutamylcysteine-ethyl ester = GCEE, U0126) that are known to inhibit autophagy? During the phase of model establishment, anesthetized Sprague-Dawley rats will be subjected to exsanguination CA and 60 min of EPR, followed by resuscitation with CPB and survival up to 72 hours; extent of autophagy will be determined ad selected timepoints by Western blot analysis, immunohistochemistry and electron microscopy. In the next step, the influence of GCEE and U0126 applied with the aortic flush on functional and histologic outcome will be assessed. All experiments will be performed in male and female subjects to study suspected gender differences in autophagic neuronal death. (b) My clincal project will be the participation in the first human EPR trial. Funding for this project has been acquired at the SCRR, and I would be involved in the protocol design, regulatory approvals, the training of medical personal, and in data acquisition during the trial. Trauma victims who have suffered a CA and have not responded promptly to standard resuscitative efforts, including an ED thoracotomy and cardiac compressions, will be included. EPR will be induced with ice-cold saline infused directly into the aorta via a large cannula. After surgery, resuscitation will be done with CPB. Primary outcome will be feasibility and safety of rapidly inducing profound cerebral hypothermia for EPR in exsanguinating trauma patients. Secondary outcome will be 28-day survival, 6- month neurologic functional outcome (assesses with Glasgow Outcome Score Extended) and the development of multiple organ dysfunction syndrome as compared to historical controls.