MicroRNAs of microglia： wrestling with central nervous system disease

Microglia serve as brain-resident myeloid cells that affect cerebral development, ischemia, neurodegeneration, and neuro-viral infection. MicroRNAs play a key role in central nervous system disease through post-transcriptional regulation. Indeed, evidence shows that microRNAs are one of the most important regulators mediating microglial activation, polarization, and autophagy, and subsequently affecting neuroinflammation and the outcome of central nervous system disease. In this review, we provide insight into the function of microRNAs, which may be an attractive strategy and influential treatment for microglia-related central nervous system dysfunction. Moreover, we comprehensively describe how microglia fight against central nervous system disease via multiple functional microRNAs.

MicroRNA expression in the hippocampal CA1 region under deep hypothermic circulatory arrest

Using deep hypothermic circulatory arrest, thoracic aorta diseases and complex heart diseases can be subjected to corrective procedures. However, mechanisms underlying brain protection during deep hypothermic circulatory arrest are unclear. After piglet models underwent 60 minutes of deep hypothermic circulatory arrest at 14°C, expression of microRNAs(miRNAs) was analyzed in the hippocampus by microarray. Subsequently, TargetScan 6.2, RNA22 v2.0, miRWalk 2.0, and miRanda were used to predict potential targets, and gene ontology enrichment analysis was carried out to identify functional pathways involved. Quantitative reverse transcription-polymerase chain reaction was conducted to verify miRNA changes. Deep hypothermic circulatory arrest altered the expression of 35 miRNAs. Twenty-two miRNAs were significantly downregulated and thirteen miRNAs were significantly upregulated in the hippocampus after deep hypothermic circulatory arrest. Six out of eight targets among the differentially expressed miRNAs were enriched for neuronal projection(cyclin dependent kinase, CDK16 and SLC1 A2), central nervous system development(FOXO3, TYRO3, and SLC1 A2), ion transmembrane transporter activity(ATP2 B2 and SLC1 A2), and interleukin-6 receptor binding(IL6 R)– these are the key functional pathways involved in cerebral protection during deep hypothermic circulatory arrest. Quantitative reverse transcription-polymerase chain reaction confirmed the results of microarray analysis. Our experimental results illustrate a new role for transcriptional regulation in deep hypothermic circulatory arrest, and provide significant insight for the development of miRNAs to treat brain injuries. All procedures were approved by the Animal Care Committee of Xuanwu Hospital, Capital Medical University, China on March 1, 2017(approval No. XW-INI-AD2017-0112).

Hypothermia selectively protects the anterior forebrain mesocircuit during global cerebral ischemia

Hypothermia is an important protective strategy against global cerebral ischemia following cardiac arrest.However,the mechanisms of hypothermia underlying the changes in different regions and connections of the brain have not been fully elucidated.This study aims to identify the metabolic nodes and connection integrity of specific brain regions in rats with global cerebral ischemia that are most affected by hypothermia treatment.18F-fluorodeoxyglucose positron emission tomography was used to quantitatively determine glucose metabolism in different brain regions in a rat model of global cerebral ischemia established at 31–33℃.Diffusion tensor imaging was also used to reconstruct and explore the brain connections involved.The results showed that,compared with the model rats established at 37–37.5℃,the rat models of global cerebral ischemia established at 31–33℃had smaller hypometabolic regions in the thalamus and primary sensory areas and sustained no obvious thalamic injury.Hypothermia selectively preserved the integrity of the anterior forebrain mesocircuit,exhibiting protective effects on the brain during the global cerebral ischemia.The study was approved by the Institutional Animal Care and Use Committee at Capital Medical University(approval No.XW-AD318-97-019)on December 15,2019.

Goal-directed Fluid Therapy May Improve Hemodynamic Stability of Parturient with Hypertensive Disorders of Pregnancy Under Combined Spinal Epidural Anesthesia for Cesarean Delivery and the Well-being of Newborns

Background： Hypotension induced by combined spinal epidural anesthesia in parturient with hypertensive disorders of pregnancy （HDP） can easily compromise blood supply to vital organs including uteroplacental perfusion and result in fetal distress. The aim of this study was to investigate whether the goal-directed fluid therapy （GDFT） with LiDCOrapid system can improve well-being of both HDP parturient and their babies. Methods： Fifty-two stable HDP parturient scheduled for elective cesarean delivery were recruited. After loading with 10 ml/kg lactated Ringer＇s solution （LR）, parturient were randomized to the GDFT and control group. In the GDFT group, individualized fluid therapy was guided by increase in stroke volume （ASV） provided via LiDCO rapid system. The control group received the routine fluid therapy. The primary endpoints included maternal hypotension and the doses of vasopressors administered prior to fetal delivery. The secondary endpoints included umbilical blood gas abnormalities and neonatal adverse events. Results： The severity of HDP was similar between two groups. The total LR infusion （P 〈 0.01） and urine output （P 〈 0.05） were higher in the GDFT group than in the control group. Following twice fluid challenge tests, the systolic blood pressure, mean blood pressure, cardiac output and SV in the GDFT group were significantly higher, and the heart rate was lower than in the control group. The incidence of maternal hypotension and doses of phenylephrine used prior to fetal delivery were significantly higher in the control group than in the GDFT group （P 〈 0.01）. There were no differences in the Apgar scores between two groups. In the control group, the mean values of pH in umbilical artery/vein were remarkably decreased （P 〈 0.05）, and the incidences of neonatal hypercapnia and hypoxemia were statistically increased （P 〈 0.05） than in the GDFT group. Conclusions： Dynamic responsiveness guided fluid therapy with the LiDCOrapid system may provide potential benefits to stable HDP parturient and their babies.

Geriatric Anesthesia-related Morbidity and Mortality in China： Current Status and Trend

Objective： The population of elderly patients and the amount of geriatric anesthesia have been growing rapidly in China. Thus, understanding the morbidity and mortality associated with geriatric anesthesia in China is critical to the improvement of anesthesia quality and outcome. The aim of the review was to discuss the geriatric anesthesia-related morbidity and mortality in China, as well as to point out the future trend. Data Sources： Articles in this review were all searched from Wanfang, China National Knowledge Infrastructure （CNKI）, VIP, PubMed, and Web of Science databases, based on the reports originated in China from January 2011 to December 2016. Study Selection： A total of 57 studies were selected for further study, including 12 retrospective studies, 35 prospective studies, 3 meta-analyses, 4 reviews, 1 viewpoint, and 2 case reports. Of the total studies, 42 studies were in Chinese while 15 were in English. Results： The mortality and morbidity associated with geriatric anesthesia in China are not yet completely reported. Some factors have been recognized, while some are yet to be identified and confirmed. Several studies addressed postoperative cognitive dysfunction and postoperative delirium, whereas only a few studies can be found on renal complications. Thus, a nationwide registry is essential for geriatric anesthesia-associated adverse outcomes. The mortality associated with geriatric anesthesia in China should be reported promptly. In the future, the perspective of geriatric anesthesia needs to be expanded into perioperative geriatric medicine to improve the perioperative management strategy based on the postoperative outcome-directed concept transformation. Conclusions： Anesthesiologists should evaluate the physiological and medical status and focus on the prevention of potential complications in the perioperative setting with the goal to enhance elderly patients＇ long-term well-being and survival quality.

An overview of Chinese multidisciplinary expert consensus on perioperative brain health in elderly patients

Goals for Developing This Consensus The rapidly aging populations in China pose serious challenges for anesthesiologists.Comorbidity and functional decline in elderly patients escalate the risks of cerebral complications which might lead to long-term morbidity and overall reduced quality of life after surgery.[1,2]Therefore,it is imperative to implement perioperative brain protection strategies for geriatric patients.

Influence of three different anesthesia protocols on aged rat brain:a resting-state functional magnetic resonance imaging study

Background:Resting-state functional magnetic resonance imaging(rs-fMRI)is a promising method for the study of brain function.Typically,rs-fMRI is performed on anesthetized animals.Although different functional connectivity(FC)in various anesthetics on whole brain have been studied,few studies have focused on different FC in the aged brain.Here,we measured FC under three commonly used anesthesia methods and analyzed data to determine if the FC in whole brain analysis were similar among groups.Methods:Twenty-four male aged Wistar rats were randomly divided into three groups(n=8 in each group).Anesthesia was performed under either isoflurane(ISO),combined ISO+dexmedetomidine(DEX)orα-chloralose(AC)according to the groups.Data of rs-fMRI was analyzed by FC in a voxel-wise way.Differences in the FC maps between the groups were analyzed by one-way analysis of variance andpost hoc two-samplet tests.Results:Compared with ISO+DEX anesthesia,ISO anesthesia caused increased FC in posterior brain and decreased FC in the middle brain of the aged rat.AC anesthesia caused global suppression as no increase in FC was observed.Conclusion:ISO could be used as a substitute for ISO+DEX in rat default mode network studies if the left temporal association cortex is not considered important.