The opening of the mitochondrial permeability transition pore (PTP), which is regulated by the matrix protein cyclophilin D (CypD), plays a key role in the pathophysiology of post-cardiac arrest (CA) syndrome. We hypothesized that therapeutic hypothermia could prevent post-CA syndrome through a CypD-mediated PTP inhibition in both heart and brain. In addition, we investigated whether specific pharmacological PTP inhibition would confer additive protection to cooling. Adult male New Zealand White rabbits underwent 15 min of CA followed by 120 min of reperfusion. Five groups (n = 10-15/group) were studied: control group (CA only), hypothermia group (HT, hypothermia at 32-34 °C induced by external cooling at reperfusion), NIM group (injection at reperfusion of 2.5 mg/kg NIM811, a specific CypD inhibitor), HT + NIM, and sham group. The following measurements were taken: hemodynamics, echocardiography, and cellular damage markers (including S100β protein and troponin Ic). Oxidative phosphorylation and PTP opening were assessed on mitochondria isolated from both brain and heart. Acetylation of CypD was measured by immunoprecipitation in both the cerebral cortex and myocardium. Hypothermia and NIM811 significantly prevented cardiovascular dysfunction, pupillary areflexia, and early tissue damage. Hypothermia and NIM811 preserved oxidative phosphorylation, limited PTP opening in both brain and heart mitochondria and prevented increase in CypD acetylation in brain. There were no additive beneficial effects in the combination of NIM811 and therapeutic hypothermia. In conclusion, therapeutic hypothermia limited post-CA syndrome by preventing mitochondrial permeability transition mainly through a CypD-dependent mechanism.

Opening of the mitochondrial permeability transition pore (mPTP) appears to be a pivotal event in myocardial ischemia-reperfusion (I/R) injury. Resuscitated cardiac arrest (CA) leads to the post-CA syndrome that encompasses, not only myocardial dysfunction, but also brain injury, failure of other organs (kidney, liver, or lung), and systemic response to I/R. We aimed to determine whether cyclosporine A (CsA) might prevent multiple organ failure following CA through a ubiquitous mPTP inhibition in each distant vital organ. Anesthetized New Zealand White rabbits were subjected to 15 min of CA and 120 min of reperfusion. At the onset of resuscitation, the rabbits received CsA, its non-immunosuppressive derivative NIM811, or vehicle (controls). Survival, hemodynamics, brain damage, organ injuries, and systemic I/R response were analyzed. Fresh mitochondria were isolated from the brain, heart, kidney, liver, and lung to assess both oxidative phosphorylation and permeability transition. CsA analogs significantly improved short-term survival and prevented multiple organ failure, including brain damage and myocardial dysfunction (P < 0.05 vs. controls). Susceptibility of mPTP opening was significantly increased in heart, brain, kidney, and liver mitochondria isolated from controls, while mitochondrial respiration was impaired (P < 0.05 vs. sham). CsA analogs prevented these mitochondrial dysfunctions (P < 0.05 vs. controls). These results suggest that CsA and NIM811 can prevent the post-CA syndrome through a ubiquitous mitochondrial protective effect at the level of each major distant organ.

Therapeutic hypothermia is neuroprotective after cardiac arrest (CA) via poorly understood mechanisms. It may prevent mitochondrial permeability transition pore (PTP) opening, an event which plays a pivotal role in ischemia-reperfusion injury. PTP is the main end-effector of the Reperfusion Injury Salvage Kinase (RISK) signaling pathway. We hypothesized that therapeutic hypothermia activates the RISK pathway, thereby preventing PTP opening and its deleterious neurological consequences after CA. Four groups of New Zealand White rabbits were subjected to 15 minutes of CA and 120 minutes of reperfusion: Control, HT (hypothermia at 32°-34°C), NIM (specific PTP inhibition with N-methyl-4-isoleucine-cyclosporine at the onset of reperfusion), and HT+NIM. A Sham group only underwent surgery. The following measurements were taken: pupillary reflexes and brain damage biomarkers (NSE and S100β), RISK pathway activation in brain cortex (total and phosphorylated forms of both Akt and ERK) and PTP opening in isolated brain mitochondria. Therapeutic hypothermia and pharmacological PTP inhibition preserved the pupillary reflexes and prevented the increase in both NSE and S100β (p < 0.05 versus controls). These two interventions also enhanced (p < 0.05 versus controls) the phospho-Akt/Akt ratio to a similar extent while preventing a CA-induced increase in phospho-ERK/ERK ratio. This Akt activation in the HT and NIM groups was associated with an attenuation of CA-induced PTP opening. In this model, therapeutic hypothermia promoted the activation of the RISK signaling pathway via Akt and limited CA-induced brain injury by preventing PTP opening.

Cirrhotic patients with septic shock have a poor prognosis in ICU compared to general population of critically ill patients. Little is known about long-term outcome in these patients. We performed a retrospective analysis of a prospective cohort of cirrhotic patients with septic shock. The aim of this study was to describe both short and long-term outcomes and to evaluate factors predicting mortality. Data from 149 patients were analyzed (mean age: 60 ± 11 years, sex ratio: 2.4). Mortality rate in the ICU was 54% and at 1 year it was 73%. Among factors associated with adverse outcome, independent factors predicting ICU mortality were early need for renal replacement therapy (odds ratios, OR 13.95, 95% confidence interval, CI 3.30; 59.03) and arterial lactate >5 mmol.L−1 (OR 7.27, 95% CI 2.92; 18.10), and early use of mechanical ventilation (OR 3.05, 95% CI 1.08; 8.58). For 1-year mortality, independent prognostic factors were the need for renal replacement therapy during ICU stay (OR 9.60, 95% CI 2.90; 31.82), prothrombin time ≤40% (OR 3.47, 95% CI 1.43; 8.43), and Charlson score (OR 1.36 per point, 95% CI 1.11; 1.67). The results emphasize the poor prognosis of cirrhotic patients with septic shock admitted to the ICU. The need for organ supports appears to be a better predictor of short-term outcome than the underlying hepatic disease. Renal replacement therapy is associated with both short and long-term outcomes.

Although the overall mortality of patients admitted to intensive care units (ICU) with hematological malignancy has decreased over the years, some groups of patients still have low survival rates. We performed a monocentric retrospective study including all patients with hematological malignancy in a ten-year period, to identify factors related to the outcome for the whole cohort and for patients with allogeneic hematopoietic stem cell transplantation (HSCT), neutropenia, or those requiring invasive mechanical ventilation (IMV). A total of 418 patients with acute leukemia (n=239; 57%), myeloma (n=69; 17%), and lymphoma (n=53; 13%) were studied. Day-28 and 1-year mortality were 49% and 72%, respectively. The type of disease was not associated with outcome. The disease status was independentlty associated with 1-year mortality only. Independent predictors of day-28 mortality were IMV, renal replacement therapy (RRT), and performance status. For allogeneic HSCT recipients (n=116), neutropenic patients (n=124) and patients requiring IMV (n=196), day-28 and 1-year mortality were 52%, 54%, 74% and 81%, 78%, 87%, respectively. Multivariate analysis showed that IMV and RRT for allogeneic HSCT recipients, performance status and IMV for neutropenic patients, and RRT for patients requiring IMV were independently associated with short-term mortality (p<0.05).These results suggest that IMV is the strongest predictor of mortality in hematological patients admitted to ICUs, whereas allogeneic HSCT and neutropenia do not worsen their short-term outcome.

Small changes in body temperature prior to asphyxial CA significantly influence brain mitochondrial functions and short-term outcomes in rabbits.

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