Mechanism And Application Research Of Brain Injury And Brain Protection During Deep Hypothermic Circulatory Arrest

General design of the study Deep hypothermic circulatory arrest commonly used in aortic surgery and complex congenital heart disease correction surgery. Deep hypothermic circulatory arrest can create no blood and quiet operative field by lowering the temperature at the same time stop the circulation.Brain injury after deep hypothermic circulatory arrest can not be avoided. In this study, we design three aspects to discuss deep hypothermic circulatory arrest brain damage and brain protection comprehensively. Provide a comprehensive strategy for deep hypothermic circulatory arrest and cerebral injury and a new direction and ideas for cerebral protection.The first part of the study is NIRS and TCD monitoring for deep hypothermic circulatory arrest.The purpose of this study is through the analysis of VmMCA flow and cerebral oxygen saturation to explore most suitable selective cerebral perfusion flow rate for DHCA and ASCP.Use cerebral oxygen saturation as a reference for clinical brain perfusion flow rate, to minimize the impact for deep hypothermic circulatory arrest on cerebral blood supply and oxygen to provide a theoretical basis. In this study we find thatthe middle cerebral artery flow velocity and cerebral oxygen saturation and venous oxygen saturation was significantly lower compared with that indes before deep hypothermic circulatory arrest.Flow spectrum of the middle cerebral artery after aortic cross-clamping can clearly see microthrombus signal.that may suggests that micro-bolt into the brain during deep hypothermic circulatory arrest and brain function maybe have some influence. That result prompted us to further study for study the pathophysiology of deep hypothermic circulatory arrest, finally to provide effective protection of the cerebral injury.The second part of this study, on the basis of preliminary studies,we establish piglet deep hypothermia circulatory arrest model to explore the post-transcriptional regulation mechanism of deep hypothermic circulatory arrest in-depth molecular and genetic level.By microarray technique, we explode dyregulatied23microRNAs, that including of miR-194, miR-200c. miR-122et al. And bioinformatic analysis found that those microRNAs involved in a variety of brain injury related diseases, and the signal transduction pathway.The third part of this study, on the basis of preliminary studies using animal models of DHCA, and basic on the microarray results, we collected patient's blood who undergoing DHCA, detect the different expression of these microRNA before and after DHCA at different time points. Meanwhile, the expression level of microRNA and CNS score correlation analysis reflected that miR-194in patients with deep hypothermic circulation and brain functional status has a good correlation.All in all, The choice of the appropriate flow rate and the monitoring of brain function improvement during deep hypothermic circulation arrest, and the exploration of deep hypothermic circulatory arrest mechanism, even on the basis of brain tissue microRNA research of deep hypothermic circulatory arrest, other drugs and non-drug application of therapeutic interventions will help the development cerebral protection of DHCA. All these delevlopment will bring the patient of the complexity of vascular disease and complex congenital heart disease patients the Gospel. Part I Real-Time Continuous Neuromonitoring Combines Transcranial Cerebral Doppler with Near-Infrared Spectroscopy cerebral oxygen saturation during deep hypothermic circulatory arrestObjective The purpose of this investigation was to use combined transcranial cerebral doppler (TCD) and near-infrared spectroscopy cerebral oxygen saturation (NIRS) during total aortic arch replacement (TAAR) to monitor middle cerebral artery blood flow velocity and regional cerebral oximetry (rSO2) changes to provide a clinical basis for protective measures that may decrease injury of the central nervous system.Methods Consecutive12adult patients underwent deep hypothermic circulatory arrest (DHCA) and antegrade selective cerebral perfusion (ASCP) during TAAR. A TCD probe was placed at the temporal windows after induction of anesthesia and the NIRS probe placed on the forehead of patients to collect preioperative. intraoperative. and postoperative hemodynamic parameters, and cerebral blood flow (CBF) and rSO2during cardiopulmonary bypass (CPB).Result In this retrospective case series, all patients survived, and there were no postoperative neurologic complications. There was no significant correlation between the mean arterial pressure and rSO2. The middle cerebral artery mean velocity (VmMCA) and rSO2were significantly correlated, and main pump flow significantly correlated with rSO2. After ASCP, VmMCA, rSO2, and venous oxygen saturation were significantly lower than before ASCP, but VmMCA and rSO2returned to pre-CPB levels postoperatively. After off pump, the flow of ASCP showed a significant positive correlation with VmMCA and rSO2. During DHCA when ASCP flow was lower than5ml/kg/min, TCD could not detect the MCA. Blood flow signal. When the flow of ASCP was above keeping around10ml/kg/min, MCA CBF velocity was maintained and rSO2>45%.Conclusion The combination of TCD and NIRS can be effective in monitoring brain function during DHCA with ASCP and may provide a guide for decreasing brain injury during the TAAR procedure. Part Ⅱ MicroRNAs Expression Profiling of Cerebral Injury in the Piglet Model of Cardiopulmonary Bypass Undergoing Deep Hypothermic Circulatory Arrest.Objective The cerebral injury after DHCA is serious problem and little is known about this molecular mechanism. In this study, we constructed DHCA piglet model to investigate expression profile of miRNAs associated with DHCA brain injuryMaterials and Methods DHCA model was conducted by six male piglets (2.0-2.5kg) including three from the DHCA group and three from the Sham group, hippocampus were harvested for miRNA microarray analysis. All microarray data were analyzed by Significance Analysis of Microarrays (SAM), and this result was further confirmed by qRT-PCR assay, biological information analysis to predict the target of the panels of miRNAs, then the GO analysis to find the function of the target by MAS.Results Thirty-five miRNAs were differentially expressed in hippocampus after DHCA procedure. Thirteen miRNAs (miR-23a, miR-27a. miR-182, et al) were significantly up-regulated and twenty-two miRNAs (miR-10b, miR-200c, miR-210, miR-150, et al) were down-regulated in DHCA hippocampus. Bioinformatic analysis of the predicted targets for this panel of miRNAs revealed multiple protein targets, biological processes and functions involved in pathphysiology of DHCA cerebral injury including signal transduction, transcriptional regulation, apoptosis, and inflammatory.Conclusion DHCA cerebral injury involves a set of miRNAs dysregulated. miR-10b, miR-200c, miR-210, miR-150, miR-23a, et al play important role in regulate cerebral injury. Part Ⅲ Expression profile of brain microRNAs in circulation is the sensitive biomarker of brain injury during deep hypothermic circulatory arrestObjective Diagnosis of the brain injury, detection of neuropsychological changes, and the judgment of neurological function are the common challenges of cardiac surgeon and perfusionists. The development of new specific biomarker is the key part to improve diagnosis and prognosis of deep hypothermic circulatory arrest brain injury. Hematology testing is a relatively easy access to biochemical measurement. In this study, basic on our previous microarray result about deep hypothermic circulatory arrest in piglet module. We choose significantly express microRNA to detect the expression change among the different time of DHCA. We purpose of this study is identify specific microRNA which is closely related to the brain injury and provide a theoretical basis for assessment of neurological injury.Materials and Methods Subject to the approval of the Ethics Committee, we selected21patients with aortic dissection randomly with proposed total arch replacement during deep hypothermic circulatory arrest and antegrade selective cerebral perfusion. Neurological conditions of patients with preoperative and postoperative different time points scored in accordance with the Canadian Neurological Scale (CANADIAN NEUROLOGICAL SCALE, CNS). We saved the blood of patients at different time points, extracted total RNA, designed miR-194, miR-200c, miR-122, miR-10b-specific stem-loop primers. Real-time quantitative PCR method to detect different point of blood samples of four kinds of microRNA expression differences. Finally, analysis correlation of differentially expressed miRNAs and CNS score.Results Deep hypothermic circulatory arrest, miR-194expression of the patient's blood at postoperative0h,12h,18h,24h, and36h time points compared with preoperative decreased significantly (P=0.000). MiR-194expression2-△CT (×103) value of preoperative is1.2629±.3622. MiR-194expression2-△CT (×103) value of postoperative is0.6699±3896. Before and after surgery have a statistically significant difference (P=0.005). After deep hypothermic circulatory arrest, miR-194level at postoperative12h is minimum. The results also showed that the Canadian Neurological Scale scores with miR-194's expression changes in blood with deep hypothermic circulatory arrest was positively related (r=0.574, P=0.000), to be co-goodness test R2=0.33. But miR-200c, miR-10b, miR-122and CNS score no significant correlation.Conclusion pre-and post-Deep hypothermic circulatory arrest the expression changes of miR-194and CNS score a positive correlation, the reflected that expression changes of miR-194in the blood correlated with neurological dysfunction, suggesting that miR-194can be used as biomarkers of neurological deficit. Follow-up study will focus on the function of miR-194participate in future.