Cardiocerebral protection by emulsified isoflurane during cardiopulmonary resuscitation

Protective effects of combined treatment with ciprofol and mild therapeutic hypothermia during cerebral ischemia-reperfusion injury

Despite improvement in cardiopulmonary resuscitation (CPR) performance, cardiac arrest (CA) is still associated with poor prognosis. The high mortality rate is due to multi-organ dysfunction caused by cerebral ischemia and reperfusion injury (I/R). The guidelines for CPR suggest the use of therapeutic hypothermia (TH) as an effective treatment to decrease mortality and the only approach confirmed to reduce I/R injury. During TH, sedative agents (propofol) and analgesia agents (fentanyl) are commonly used to prevent shiver and pain. However, propofol has been associated with a number of serious adverse effects such as metabolic acidosis, cardiac asystole, myocardial failure, and death. In addition, mild TH alters the pharmacokinetics of agents (propofol and fentanyl) and reduces their systemic clearance. For CA patients undergoing TH, propofol can be overdosed, leading to delayed awakening, prolonged mechanical ventilation, and other subsequent complications. Ciprofol (HSK3486) is a novel anesthetic agent that is convenient and easy to administer intravenously outside the operating room. Ciprofol is rapidly metabolized and accumulates at low concentrations after continuous infusion in a stable circulatory system compared to propofol. Therefore, we hypothesized that treatment with HSK3486 and mild TH after CA could protect the brain and other organs.

Sedative depth on neurological outcomes in a juvenile rat model of cardiopulmonary resuscitation

The guidelines for cardiopulmonary resuscitation (CPR) in pediatric advanced life support suggest that midazolam is the preferred agent for sedation in patients with mild hypothermia, whereas children with cardiac arrest (CA) are at a crucial stage regarding their immature nervous system. Studies have shown that midazolam may have a detrimental effect on the developmental of the pediatric nervous system. Our previous study found that midazolam induced neuronal damage after CPR in young rats. It is speculated that: midazolam causes the potential injury of neurons by inhibiting mitochondrial autophagy expression and is an important factor for the poor prognosis in children after successful CPR. This project intends to adopt the modified asphyxiant CPR model in juvenile rats. Survival rate, neurological function and histopathological changes were evaluated to determine the protective effects of appropriate sedation depth on cerebral ischemia-reperfusion injury in juvenile rats after CPR. Combined with cell biology and molecular biology related technologies, the mechanism by which the mitochondrial pinkl-parkin signaling pathway induces autophagy to inhibit neuronal apoptosis may be key factor in the protective effects of sedation depth on the brain. The aim of this study is to provide experimental evidence and elucidate the mechanisms of improvement of cerebral ischemia-reperfusion injury by sedation depth in children after successful CPR and to lay a theoretical and experimental basis for clinical treatment.

Emulsified isoflurane postconditioning improves survival and neurological outcomes in a rat model of cardiac arrest

Emulsified isoflurane (EIso) has a protective effect against ischemia/reperfusion (I/R) injury in animal models. However, the protective effects of EIso on global cerebral I/R injury remain unclear. The present study aimed to investigate whether EIso postconditioning was able to improve survival and neurological outcomes in a rat model of cardiac arrest (CA). Rats were randomly divided into five groups, namely the control, EIso-2ml, EIso-4ml, isoflurane (Iso) and emulsion (E) groups. All rats were resuscitated by a standardized method following 6 min of asphyxia. Furthermore, all interventions were administered immediately following the return of spontaneous circulation (ROSC). The animal survival was recorded daily, and evaluations of behavioral and brain morphology were assessed at 1 and 7 days after ROSC. The results showed that EIso treatment increased the survival rate 7 days after ROSC, with a 41.7% 7-day survival in the EIso-2ml group, 66.7% in the EIso-4ml group and 50% in the Iso group compared with 33.3% survival in the control and E groups. Moreover, the neural deficit score and memory function were improved in the EIso-4ml group, and this treatment also ameliorated brain hippocampal cell injury and apoptosis. In addition, a better brain protective effect was observed in the EIso-4ml group compared with the EIso-2ml, Iso and E groups. In summary, the data of the present study suggest that EIso postconditioning improved the survival and neurological outcomes following CA in a dose-dependent manner.

Augmented O-GlcNAc signaling via glucosamine attenuates oxidative stress and apoptosis following contrast-induced acute kidney injury in rats

Contrast-induced acute kidney injury (CI-AKI) is an iatrogenic renal injury and associated with substantial morbidity and mortality in susceptible individuals. Despite extensive study of a variety of agents for renal protection, limited strategies have been shown to be effective in the reduction of CI-AKI. O-linked β-N-acetylglucosamine (O-GlcNAc) is a post-translational regulatory modification of intracellular proteins and governs the function of numerous proteins, both cytosolic and nuclear. Increasing evidence suggests that O-GlcNAc levels are increased in response to stress and that acute augmentation of this reaction is cytoprotective. However, the underlying mechanisms by which augmented OGlcNAc signaling provides renoprotection against contrast media insults is still unknown. Here, we investigated the effect of augmented O-GlcNAc signaling via glucosamine on CI-AKI and explored the underlying molecular mechanisms, particularly its relationship with PI3-kinase (PI3K)/Akt signaling. We used a novel and reliable CI-AKI model consisting of 5/6 nephrectomized (NE) rats, and a low-osmolar contrast media (iohexol, 10mL/kg, 3.5gI) injected via the tail vein after dehydration for 48h. The results showed that augmented O-GlcNAc signaling by glucosamine prevented the kidneys against iohexol-induced injury characterized by the attenuation of renal dysfunction, tubular damage, apoptosis and oxidative stress. Furthermore, this renoprotection was blocked by treatment with alloxan, an O-GlcNAc transferase inhibitor. Augmented O-GlcNAc signaling also increased the protein expression levels of phospho-Akt (Ser473, but not Thr308 and Thr450), phospho-GSK-3β, Nrf2, and Bcl-2, and decreased the levels of Bax and cleaved caspase-3. Both alloxan and specific inhibitors of PI3K (Wortmannin and LY294002) blocked the protection of glucosamine via inhibiting Akt signaling pathway. We further identified O-GlcNAcylated Akt through immunoprecipitation and western blot. We confirmed that Akt was modified by O-GlcNAcylation, and glucosamine pretreatment increased the O-GlcNAcylation of Akt. Collectively, the results demonstrate that glucosamine induces renoprotection against CI-AKI through augmented O-GlcNAc and activation of PI3K/Akt signaling, making it a promising strategy for preventing CI-AKI.

Emulsified isoflurane combined with therapeutic hypothermia improves survival and neurological outcomes in a rat model of cardiac arrest

Emulsified isoflurane (EIso), when introduced following cardiopulmonary resuscitation (CPR), significantly improves survival and neurological outcomes in a rat model of cardiac arrest (CA). The present study aimed to examine whether EIso combined with therapeutic hypothermia (TH) confers an additive neuroprotective effect. Adult male Sprague-Dawley rats that were subjected to return of spontaneous circulation (ROSC) after a 6-min asphyxia-induced CA were randomized to five groups: Sham group, control group under normothermic conditions, EIso group (4 ml/kg for 30 min under normothermic conditions), TH group (33°C for 2 h), and EIso plus TH group. Survival conditions and neurological outcomes were evaluated at 1 day and 7 days after ROSC. Animal survival rate at 7 days after ROSC was 30.7% in the CPR group, 60% in the EIso group, 63.6% in the TH group and 72.7% in the EIso plus TH group. EIso, TH and EIso plus TH yielded significant improvements in survival rates, neural deficit score and cognitive function, and ameliorated hippocampal CA1 region cell injury and apoptosis at 1 day and 7 days after ROSC compared with the CPR group. Combined therapy of EIso and TH was superior to EIso or TH alone, suggesting that combined EIso and TH treatment results in significant improvements in survival and neurological outcomes, and was more effective than independent EIso or TH treatment.