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Background Post‐resuscitation syndrome, involves a severe inflammatory response following successful cardiopulmonary resuscitation. The potential mechanism of Vitamin C (VitC) after cardiopulmonary resuscitation on myocardial and cerebral function, duration of survival is undefined. Methods and Results A first set of experiments were done in 18 male Sprague‐Dawley rats for the investigation of short‐term follow‐up, randomized into 3 groups: (1) sham; (2) controls; (3) VitC. Ventricular fibrillation was electrically induced and untreated for 6 minutes. Cardiopulmonary resuscitation including chest compression and mechanical ventilation were then initiated and continued for 8 minutes followed by defibrillation. At 5 minutes after return of spontaneous circulation, either VitC (200 mg/kg) or placebo was administered by intravenous infusion with a syringe pump for half an hour. There were significant improvements in myocardial function and buccal microcirculation in rats treated with VitC after return of spontaneous circulation 4 hours compared with controls. VitC inhibited proinflammatory cytokines (interleukin‐6 and tumor necrosis factor‐α), SDC‐1 (Syndecan‐1), and hyaluronic acid in plasma compared with controls (P

Background To investigate the therapeutic potential of combined therapy with polyethylene glycol‐20k (PEG‐20k) and MCC950 on post‐resuscitation myocardial function in a rat model of cardiac arrest. Methods and Results Thirty rats were randomized into 5 groups: Sham, Control, PEG‐20k, MCC950, PEG‐20k+ MCC950. Except for sham, animals were subjected to 6 minutes of ventricular fibrillation followed by 8 minutes cardiopulmonary resuscitation. Two milliliters PEG‐20k was administered by intravenous injection coincident with the start of cardiopulmonary resuscitation; MCC950 (10 mg/kg), a highly selective NLRP3 inflammasome inhibitor, was delivered immediately after restoration of spontaneous circulation. Myocardial function, sublingual microcirculation, mitochondrial function, plasma cardiac troponin I, and interleukin‐1β, expression of proteins in SIRT1 (sirtuin 1)/PGC‐1α (peroxisome proliferator‐activated receptor gamma coactivator 1‐alpha) and NLRP3 (the NOD‐like receptor family protein 3) inflammasome pathways were evaluated. Following cardiopulmonary resuscitation, myocardial function was compromised with a significantly decreased cardiac output, ejection fraction, and increased myocardial performance index, cardiac troponin I. Sublingual microcirculation was disturbed with impaired perfused vessel density and microvascular flow index. Cardiac arrest reduced mitochondrial routine respiration, Complex I‐linked respiration, respiratory control rates and oxidative phosphorylation coupling efficiency. PEG‐20k or MCC950 alone restored mitochondrial respiratory function, restituted sublingual microcirculation, and preserved myocardial function, whereas a combination of PEG‐20k and MCC950 further improved these aspects. PEG‐20k restored the expression of SIRT1 and PGC‐1α, and blunted activation of NLRP3 inflammasomes. MCC950 suppressed expression of cleaved‐caspase‐1/pro‐caspase‐1, ASC (apoptosis‐associated speck‐like protein), GSDMD [gasdermin d], and interleukin‐1β. Conclusions Combined therapy with PEG‐20k and MCC950 is superior to either therapy alone for preserving post‐resuscitated myocardial function, restituting sublingual microcirculation at restoration of spontaneous circulation at 6 hours. The responsible mechanisms involve upregulated expression of SIRT1/PGC1‐α in tandem with inhibition of NLRP3 inflammasomes.

BackgroundEpinephrine administered during cardiopulmonary resuscitation (CPR) is associated with severe post‐resuscitation myocardial dysfunction. We previously demonstrated that therapeutic hypothermia reduced the severity of post‐resuscitation myocardial dysfunction caused by epinephrine; however, the relationship between myocardial adrenoceptor expression and myocardial protective effects by hypothermia remains unclear. Methods and ResultsRats weighing between 450 and 550 g were randomized into 5 groups: (1) normothermic placebo, (2) normothermic epinephrine, (3) hypothermic placebo, (4) hypothermic epinephrine, and (5) sham (not subject to cardiac arrest and resuscitation). Ventricular fibrillation was induced and untreated for 8 minutes for all other groups. Hypothermia was initiated coincident with the start of CPR and maintained at 33±0.2°C for 4 hours. Placebo or epinephrine was administered 5 minutes after the start of CPR and 3 minutes before defibrillation. Post‐resuscitation ejection fraction was measured hourly for 4 hours then hearts were harvested. Epinephrine increased coronary perfusion pressure during CPR (27±6 mm Hg versus 21±2 mm Hg P