Observation of the effect of hypothermia therapy combined with optimized nursing on brain protection after cardiopulmonary resuscitation: A retrospective case-control study

This study aimed to investigate the impact of optimized emergency nursing in conjunction with mild hypothermia nursing on neurological prognosis, hemodynamics, and complications in patients with cardiac arrest. A retrospective analysis was conducted on the medical records of 124 patients who received successful cardiopulmonary resuscitation (CPR) at Fujian Provincial Hospital South Branch. The patients were divided into control and observation groups, each consisting of 62 cases. The brain function of both groups was assessed using the Glasgow Coma Scale and the National Institutes of Health Stroke Scale. Additionally, serum neuron-specific enolase level was measured in both groups. The vital signs and hemodynamics of both groups were analyzed, and the complications and satisfaction experienced by the 2 groups were compared. The experimental group exhibited significantly improved neurological function than the control group (P < .05). Furthermore, the heart rate in the experimental group was significantly lower than the control group (P < .05). However, no significant differences were observed in blood oxygen saturation, mean arterial pressure, central venous pressure, and systolic blood pressure between the 2 groups (P > 0.05). Moreover, the implementation of optimized nursing practices significantly reduced complications and improved the quality of life and satisfaction of post-CPR patients (P < .05). The integration of optimized emergency nursing practices in conjunction with CPR improves neurological outcomes in patients with cardiac arrest.

Effects of Dexmedetomidine on Cognitive Function, Oxidative Stress and Brain Protection in Patients Undergoing Craniocerebral Surgery

BACKGROUND

The protective mechanism of dexmedetomidine on the brains of patients undergoing craniocerebral surgery remains unclear. The aim of this study was to examine the impact of dexmedetomidine on cognitive function, oxidative stress, and brain protection in such patients.

METHODS

Fifty-four patients who underwent craniocerebral surgery at our hospital from January 2020 to June 2023 were retrospectively selected as study subjects. They were divided into two groups: the control group (n = 27) and the study group (n = 27), based on different auxiliary anesthesia protocols. Patients in the study group received dexmedetomidine before anesthesia induction, using a midline intravenous pump to assist anesthesia, while the control group received an equivalent amount of normal saline. The remaining anesthesia induction and maintenance protocols were consistent for both groups. Cognitive function was assessed using the Mini Mental State Examination (MMSE) before and 1 day after surgery for both groups. Oxidative stress indicators, including malondialdehyde (MDA), glutathione peroxidase (GSH-Px), and superoxide dismutase (SOD) levels in the serum of both groups, were measured using enzyme-linked immunosorbent assay (ELISA). Additionally, changes in postoperative brain injury indicators, namely neuron-specific enolase (NSE) and central nervous system-specific protein (S100β), were detected and compared in the serum of both groups. Concurrently, postoperative adverse reactions were recorded for both groups.

RESULTS

The MMSE scale scores of both groups of patients 24 hours after surgery were significantly lower than those before surgery. However, the MMSE scale scores of the study group patients were notably higher than those in the control group, with a statistically significant difference (p < 0.05). One hour after surgery, the serum levels of MDA, GSH-Px, and SOD in both groups of patients were significantly elevated compared to pre-surgery levels. Yet, the study group exhibited significantly lower levels of MDA, GSH-Px, and SOD in comparison to the control group, and these differences were statistically significant (p < 0.05). The serum levels of NSE and S100β in both groups were markedly higher than preoperative levels 24 hours after surgery. However, the study group demonstrated significantly lower levels of serum NSE and S100β compared to the control group, with a statistically significant difference (p < 0.05). The incidence of postoperative complications in the study group was 7.41% (2/27), indicating a decreasing trend compared to 18.52% (5/27) in the control group. However, this difference did not reach statistical significance (χ2 = 1.477, p = 0.224).

CONCLUSION

Dexmedetomidine-assisted anesthesia in craniocerebral surgery can effectively enhance postoperative cognitive function, mitigate oxidative stress, and facilitate overall postoperative recovery for patients. The intervention exhibits a favorable safety profile with no reported serious adverse reactions, establishing it as a relatively safe and reliable approach.

The Catastrophe of Intracerebral Hemorrhage Drives the Capillary-Hemorrhage Dementias, Including Alzheimer's Disease

This review advances an understanding of several dementias, based on four premises. One is that capillary hemorrhage is prominent in the pathogenesis of the dementias considered (dementia pugilistica, chronic traumatic encephalopathy, traumatic brain damage, Alzheimer's disease). The second premise is that hemorrhage introduces four neurotoxic factors into brain tissue: hypoxia of the tissue that has lost its blood supply, hemoglobin and its breakdown products, excitotoxic levels of glutamate, and opportunistic pathogens that can infect brain cells and induce a cytotoxic immune response. The third premise is that where organisms evolve molecules that are toxic to itself, like the neurotoxicity ascribed to hemoglobin, amyloid- (A), and glutamate, there must be some role for the molecule that gives the organism a selection advantage. The fourth is the known survival-advantage roles of hemoglobin (oxygen transport), of A (neurotrophic, synaptotrophic, detoxification of heme, protective against pathogens) and of glutamate (a major neurotransmitter). From these premises, we propose 1) that the brain has evolved a multi-factor response to intracerebral hemorrhage, which includes the expression of several protective molecules, including haptoglobin, hemopexin and A; and 2) that it is logical, given these premises, to posit that the four neurotoxic factors set out above, which are introduced into the brain by hemorrhage, drive the progression of the capillary-hemorrhage dementias. In this view, A expressed at the loci of neuronal death in these dementias functions not as a toxin but as a first responder, mitigating the toxicity of hemoglobin and the infection of the brain by opportunistic pathogens.

Protective Effects of Sophoraflavanone G by Inhibiting TNF-α-Induced MMP-9-Mediated Events in Brain Microvascular Endothelial Cells

The regulation of matrix metalloproteinases (MMPs), especially MMP-9, has a critical role in both physiological and pathological events in the central nervous system (CNS). MMP-9 is an indicator of inflammation that triggers several CNS disorders, including neurodegeneration. Tumor necrosis factor-α (TNF-α) has the ability to stimulate the production of different inflammatory factors, including MMP-9, in several conditions. Numerous phytochemicals are hypothesized to mitigate inflammation, including the CNS. Among them, a flavonoid compound, sophoraflavanone G (SG), found in Sophora flavescens has been found to possess several medicinal properties, including anti-bacterial and anti-inflammatory effects. In this study, mouse brain microvascular endothelial cells (bMECs) were used to explore TNF-α-induced MMP-9 signaling. The effects of SG on TNF-α-induced MMP-9 expression and its mechanisms were further evaluated. Our study revealed that the expression of MMP-9 in bMECs was stimulated by TNF-α through the activation of ERK1/2, p38 MAPK, and JNK1/2 via the TNF receptor (TNFR) with a connection to the NF-κB signaling pathway. Moreover, we found that SG can interact with the TNFR. The upregulation of MMP-9 by TNF-α may lead to the disruption of zonula occludens-1 (ZO-1), which can be mitigated by SG administration. These findings provide evidence that SG may possess neuroprotective properties by inhibiting the signaling pathways associated with TNFR-mediated MMP-9 expression and the subsequent disruption of tight junctions in brain microvascular endothelial cells.

Twelve protections evolved for the brain, and their roles in extending its functional life

As human longevity has increased, we have come to understand the ability of the brain to function into advanced age, but also its vulnerability with age, apparent in the age-related dementias. Against that background of success and vulnerability, this essay reviews how the brain is protected by (by our count) 12 mechanisms, including: the cranium, a bony helmet; the hydraulic support given by the cerebrospinal fluid; the strategically located carotid body and sinus, which provide input to reflexes that protect the brain from blood-gas imbalance and extremes of blood pressure; the blood brain barrier, an essential sealing of cerebral vessels; the secretion of molecules such as haemopexin and (we argue) the peptide Aβ to detoxify haemoglobin, at sites of a bleed; autoregulation of the capillary bed, which stabilises metabolites in extracellular fluid; fuel storage in the brain, as glycogen; oxygen storage, in the haemoprotein neuroglobin; the generation of new neurones, in the adult, to replace cells lost; acquired resilience, the stress-induced strengthening of cell membranes and energy production found in all body tissues; and cognitive reserve, the ability of the brain to maintain function despite damage. Of these 12 protections, we identify 5 as unique to the brain, 3 as protections shared with all body tissues, and another 4 as protections shared with other tissues but specialised for the brain. These protections are a measure of the brain's vulnerability, of its need for protection. They have evolved, we argue, to maintain cognitive function, the ability of the brain to function despite damage that accumulates during life. Several can be tools in the hands of the individual, and of the medical health professional, for the lifelong care of our brains.

Validation of a new model of selective antegrade cerebral perfusion with circulatory arrest in rats

BACKGROUND

Selective antegrade cerebral perfusion (SACP) is adopted as an alternative to deep hypothermic circulatory arrest (DHCA) during aortic arch surgery. However, there is still no preclinical evidence to support the use of SACP associated with moderate hypothermia (28-30°C) instead of DHCA (18-20°C). The present study aims to develop a reliable and reproducible preclinical model of cardiopulmonary bypass (CPB) with SACP applicable for assessing the best temperature management.

MATERIALS AND METHODS

A central cannulation through the right jugular vein and the left carotid artery was performed, and CPB was instituted.Animals were randomized into two groups: normothermic circulatory arrest without or with cerebral perfusion (NCA vs SACP). EEG monitoring was maintained during CPB. After 10 min of circulatory arrest, rats underwent 60 min of reperfusion. After that, animals were sacrificed, and brains were collected for histology and molecular biology analysis.

RESULTS

Power spectral analysis of the EEG signal showed decreased activity in both cortical regions and lateral thalamus in all rats during the circulatory arrest. Only SACP determined complete recovery of brain activity and higher power spectral signal compared to NCA (p < 0.05). Histological damage scores and western blot analysis of inflammatory and apoptotic proteins like caspase-3 and Poly-ADP ribose polymerase (PARP) were significantly lower in SACP compared to NCA. Vascular endothelial growth factor (VEGF) and RNA binding protein 3 (RBM3) involved in cell-protection mechanisms were higher in SACP, showing better neuroprotection (p < 0.05).

CONCLUSIONS

SACP by cannulation of the left carotid artery guarantees good perfusion of the whole brain in this rat model of CPB with circulatory arrest. The present model of SACP is reliable, repeatable, and not expensive, and it could be used in the future to achieve preclinical evidence for the best temperature management and to define the best cerebral protection strategy during circulatory arrest.

Research progress on the role of hormones in ischemic stroke

Ischemic stroke is a major cause of death and disability around the world. However, ischemic stroke treatment is currently limited, with a narrow therapeutic window and unsatisfactory post-treatment outcomes. Therefore, it is critical to investigate the pathophysiological mechanisms following ischemic stroke brain injury. Changes in the immunometabolism and endocrine system after ischemic stroke are important in understanding the pathophysiological mechanisms of cerebral ischemic injury. Hormones are biologically active substances produced by endocrine glands or endocrine cells that play an important role in the organism's growth, development, metabolism, reproduction, and aging. Hormone research in ischemic stroke has made very promising progress. Hormone levels fluctuate during an ischemic stroke. Hormones regulate neuronal plasticity, promote neurotrophic factor formation, reduce cell death, apoptosis, inflammation, excitotoxicity, oxidative and nitrative stress, and brain edema in ischemic stroke. In recent years, many studies have been done on the role of thyroid hormone, growth hormone, testosterone, prolactin, oxytocin, glucocorticoid, parathyroid hormone, and dopamine in ischemic stroke, but comprehensive reviews are scarce. This review focuses on the role of hormones in the pathophysiology of ischemic stroke and discusses the mechanisms involved, intending to provide a reference value for ischemic stroke treatment and prevention.

Protective effect of isoflurane preconditioning on neurological function in rats with HIE

Hypoxic-ischemic encephalopathy (HIE) is an important cause of neonatal death and disability, which can lead to long-term neurological and motor dysfunction. Currently, inhalation anesthetics are widely used in surgery, and some studies have found that isoflurane (ISO) may have a positive effect on neuroprotection. In this paper, we investigated whether ISO pretreatment has a neuroprotective effect on the neurological function of HIE rats. Here, 7-day-old neonatal rats were randomly divided into a sham group, a hypoxic-ischemic (HI) group, and an ISO pretreatment (pretreatment) group. The pretreatment group was pretreated with 2% ISO for 1 h, followed by the HI group to establish an HI animal model. The HI‑induced neurological injury was evaluated by Zea‑Longa scores and triphenyltetrazolium (TTC) staining. Neuronal number and histomorphological changes were observed with Nissl staining and Hematoxylin-eosin (HE) staining. In addition, motor learning memory function was evaluated by the Morris water maze (MWM), the Y-maze, and the rotarod tests. HI induced severe neurological dysfunction, brain infarction, and cell apoptosis as well as obvious neuron loss in neonatal rats. In the MWM, the rats in the pretreatment group showed a decrease in escape latency (p = 0.042), indicating that pretreatment with ISO could improve the learning ability of HI rats. The results of Nissl staining showed that in the HI group, there was an irregular arrangement of neurons and nuclear fixation; however, the cell damage was significantly reduced and the total number of neurons was increased after ISO pretreatment (p < 0.001). In conclusion, ISO pretreatment improved cognitive function and attenuated HI-induced reduction of Nissl-positive cells and spatial memory impairment, suggesting that pretreatment with ISO before HI modeling could reduce neuronal cell death in the hippocampus after HI.

Woodpeckers minimize cranial absorption of shocks

The skull of a woodpecker is hypothesized to serve as a shock absorber that minimizes the harmful deceleration of its brain upon impact into trees^1-11 and has inspired the engineering of shock-absorbing materials^12-15 and tools, such as helmets.¹⁶ However, this hypothesis remains paradoxical since any absorption or dissipation of the head's kinetic energy by the skull would likely impair the bird's hammering performance⁴ and is therefore unlikely to have evolved by natural selection. In vivo quantification of impact decelerations during pecking in three woodpecker species and biomechanical models now show that their cranial skeleton is used as a stiff hammer to enhance pecking performance, and not as a shock-absorbing system to protect the brain. Numerical simulations of the effect of braincase size and shape on intracranial pressure indicate that the woodpeckers' brains are still safe below the threshold of concussions known for primate brains. These results contradict the currently prevailing conception of the adaptive evolution of cranial function in one of nature's most spectacular behaviors. VIDEO ABSTRACT.

Reactive Oxygen Species Scavenging Functional Hydrogel Delivers Procyanidins for the Treatment of Traumatic Brain Injury in Mice

Traumatic brain injury (TBI) is accompanied by the overload of reactive oxygen species (ROS), which can result in secondary brain injury. Although procyanidins (PCs) have a powerful free radical scavenging capability and have been widely studied in the treatment of TBI, conventional systemic drug therapy cannot make the drug reach the targeted area in the early stage of TBI and will cause systemic side effects because of the presence of the blood-brain barrier (BBB). To address this tissue, we designed and fabricated a ROS-scavenging functional hydrogel loaded PC (GelMA-PPS/PC) to deliver the drug by responding to the traumatic microenvironment. In situ injection of the GelMA-PPS/PC hydrogel effectively avoided the BBB and was directly applied to the surface of brain tissue to target the traumatic area. Hydrophobic poly(propylene sulfide)60 (PPS60), an ROS quencher and H2O2-responsive substance, was covalently bound to GelMA and exposed in response to the trauma microenvironment. At the same time, the H2O2 response of PPS60 further caused the structure of the hydrogel to degrade and release the encapsulated PC. Then PC could regulate the oxidative stress response in the cells and synergistically deplete ROS to play a neurotrophic protective role. This work suggests a novel method for the treatment of secondary brain injury by inhibiting the oxidative stress response after TBI.

Cerebral infarction after cardiac surgery

Cerebral infarction, a common central nervous system complication after adult cardiac surgery, is one of the main factors leading to the poor prognosis of cardiac surgery patients besides cardiac insufficiency. However, there is currently no effective treatment for cerebral infarction. Therefore, early prevention and diagnosis of postoperative cerebral infarction are particularly important. There are many factors and mechanisms during and after cardiac surgery that play an important role in the occurrence of postoperative cerebral infarction, such as intraoperative embolism, systemic inflammatory response syndrome, atrial fibrillation, temperature regulation, blood pressure control, use of postoperative blood products, and so forth. The mechanism by which most risk factors act on the human body, leading to postoperative cerebral infarction, is not well understood, and further research is needed. Therefore, this paper aims to summarize and explain the relevant risk factors, mechanisms, clinical signs, imaging characteristics, and early diagnosis methods of cerebral infarction complications after cardiac surgery, and provides useful data for the establishment of related diagnosis and treatment standards.

FDG-PET/CT Assessment of the Cerebral Protective Effects of Hydrogen in Rabbits with Cardiac Arrest

BACKGROUND

Anatomical imaging methods and histological examinations have limited clinical value for early monitoring of brain function damage after cardiac arrest (CA) in vivo.

OBJECTIVE

We aimed to assess the cerebral protective effects of hydrogen in rabbits with CA by using fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT).

METHODS

Male rabbits were divided into the hydrogen-treated (n=6), control (n=6), and sham (n=3) groups. Maximum standardized uptake values (SUVmax) were measured by FDG-PET/CT at baseline and post-resuscitation. Blood Ubiquitin C-terminal hydrolase-L1 (UCH-L1) and neuron specific enolase (NSE) were measured before and after the operation. After surgical euthanasia, brain tissues were extracted for Nissl staining.

RESULTS

SUVmax values first decreased at 2 and 24 h after resuscitation before rising in the hydrogen-treated and control groups. SUVmax values in the frontal, occipital, and left temporal lobes and in the whole brain were significantly different between the hydrogen and control groups at 2 and 24 h post-resuscitation (P<0.05). The neurological deficit scores at 24 and 48 h were lower in the hydrogen-treated group (P<0.05). At 24 h, the serum UCH-L1 and NSE levels were increased in the hydrogen and control groups (P<0.05), but not in the sham group. At 48 and 72 h post-CA, the plasma UCH-L1 and NSE levels in the hydrogen and control groups gradually decreased. Neuronal damage was smaller in the hydrogen group compared with the control group at 72 h.

CONCLUSION

FDG-PET/CT could be used to monitor early cerebral damage, indicating a novel method for evaluating the protective effects of hydrogen on the brain after CA.

Isolation and Characterization of Natural Nanoparticles in Naoluo Xintong Decoction and Their Brain Protection Research

Currently, researchers use modern analytical techniques in a unique perspective of physical pharmacy to analyze the phase composition of traditional Chinese medicine (TCM) and have discovered that natural nanoparticles commonly exist in decoctions. This study aims to isolate and characterize the structure and composition of nanoparticles in Naoluo Xintong (NLXT) and investigate whether the brain protection effect of NLXT is closely related to NLXT-Nanoparticles (NLXT-NPs). Firstly, the dialysis-centrifugation method was used to separate the nanoparticles and then their size distribution, potential, and morphology were characterized. In addition, infrared spectroscopy and ultra-high performance liquid chromatography-quadrupole-time of flight-mass spectrometer (UPLC-Q-TOF-MS) technology were used to analyze the composition of nanoparticles. As for the pharmacodynamic experiment, Sprague Dawley (SD) rats were randomly divided into sham, Middle cerebral artery occlusion (MCAO) model, NLXT, NLXT with nanoparticles removing (NLXT-RN), NLXT-RN+Nanoparticles (NLXT-RN+NPs), and NLXT-NPs groups. After administration, the neurological function, histopathological changes, oxidative stress, and apoptosis level were measured. Our research showed that NLXT-NPs are mainly composed of polysaccharides, proteins, and saponins, with typical characteristics of two hundred-nanometer size and negatively loaded. NLXT can improve nerve function, reduce oxidative stress, and inhibit cell apoptosis. However, removing nanoparticles can significantly reduce the brain-protective effect of NLXT, which indicates that NLXT-NPs play an essential role in the efficacy of NLXT.

Sodium tanshinone IIA sulfonate ameliorates cerebral ischemic injury through regulation of angiogenesis

Vascular remodeling and neuroprotection are two major adaptable methods for treating ischemic stroke. Edaravone is a protective agent for the treatment of stroke and was used as a positive control in the present study. Sodium tanshinone IIA sulfonate (STS) has demonstrated therapeutic clinical effects in cerebral infarction in China, while its mechanisms of action in ischemic stroke have remained elusive. The angiogenesis and neuroprotective effects of STS were evaluated in a rat model induced by middle cerebral artery occlusion and 3 days of reperfusion. When used at the same dose, the magnitude of the therapeutic effect of STS was similar to that of edaravone in terms of decreased blood-brain barrier damage as indicated by reduced Evans blue leakage, improved neurological deficits, alleviated cerebral edema and inhibition of histopathological changes caused by ischemia/reperfusion. The TUNEL assay demonstrated that the ability of STS to inhibit neuronal apoptosis was equivalent to that of edaravone. Immunofluorescence detection of CD31 and α-smooth muscle actin indicated that the vascular density was significantly reduced in the vehicle group compared with that in the sham operation group, STS increased the microvessel density in the ischemic area. Furthermore, in the vehicle group the protein expression of vascular endothelial growth factor (VEGF) and VEGF receptor 2 (VEGFR) as determined by fluorescence microscopy and immunohistochemistry was significantly reduced compared with that in the sham group. However, STS promoted their expression compared to the vehicle group respectively, and increaed the mRNA expression of VEGF, VEGFR, CD31 and angiopoietin-1 as determined by reverse transcription-quantitative PCR, but these changes were not significant or not present for edaravone apart from Ang-1. In conclusion, STS protected against ischemic brain injury by promoting angiogenesis in ischemic areas and inhibiting neuronal apoptosis. These results provide a potential treatment for stroke recovery.

Rapalink-1 Increased Infarct Size in Early Cerebral Ischemia-Reperfusion With Increased Blood-Brain Barrier Disruption

It has been reported that the mechanistic target of rapamycin (mTOR) pathway is involved in cerebral ischemia–reperfusion injury. One of the important pathological changes during reperfusion after cerebral ischemia is disruption of blood–brain barrier (BBB). Rapamycin, a first-generation mTOR inhibitor, produces divergent effects on neuronal survival and alteration in BBB disruption. In this study, we investigated how Rapalink-1, a third-generation mTOR inhibitor, would affect neuronal survival and BBB disruption in the very early stage of cerebral ischemia–reperfusion that is within the time window of thrombolysis therapy. The middle cerebral artery occlusion (MCAO) was performed in rats under isoflurane anesthesia with controlled ventilation. Of note, 2 mg/kg of Rapalink-1 or vehicle was administered intraperitoneally 10 min after MCAO. After 1 h of MCAO and 2 h of reperfusion, the transfer coefficient (K_i) of ¹⁴C-α-aminoisobutyric acid (104 Da) and the volume of ³H-dextran (70,000 Da) distribution were determined to assess the degree of BBB disruption. At the same time points, phosphorylated S6 (Ser240/244) and Akt (Ser473) as well as matrix metalloproteinase-2 (MMP2) protein level were determined by Western blot along with the infarct size using tetrazolium stain. Rapalink-1 increased the K_i in the ischemic-reperfused cortex (IR-C, +23%, p < 0.05) without a significant change in the volume of dextran distribution. Rapalink-1 increased the percentage of cortical infarct out of the total cortical area (+41%, p < 0.005). Rapalink-1 significantly decreased phosphorylated S6 and Akt to half the level of the control rats in the IR-C, which suggests that both of the mechanistic target of rapamycin complex 1 and 2 (mTORC1 and mTORC2) were inhibited. The MMP2 level was increased suggesting that BBB disruption could be aggravated by Rapalink-1. Taken together, our data suggest that inhibiting both mTORC1 and mTORC2 by Rapalink-1 could worsen the neuronal damage in the early stage of cerebral ischemia–reperfusion and that the aggravation of BBB disruption could be one of the contributing factors.

Novel Brain Protection Method for Zone 0 Endovascular Aortic Repair with Selective Cerebral Perfusion

Objective: Zone 0 thoracic endovascular aortic repair (TEVAR) is associated with a high incidence of cerebral infarction mostly due to the embolic shower of a plaque from the aortic arch when the stent graft brushes against the aortic wall. Thus, it is important to develop a method for protecting the brain from such embolism. We report the outcomes of Zone 0 TEVAR with a novel brain protection method using selective cerebral perfusion under extracorporeal membrane oxygenation (ECMO).

Materials and Methods: Two T-shaped grafts with ringed expanded polytetrafluoroethylene (ePTFE) were created using an 8-mm-ringed ePTFE anastomosed end-to-side with a 7-mm-ringed ePTFE. Carotid–carotid bypass and axillo-axillary bypass were established using these grafts. ECMO was connected to the grafts and the femoral vein. Bilateral carotid and axillary arteries were blocked, and cerebral perfusion was selectively maintained using ECMO. Total endovascular Zone 0 TEVAR was performed. The patency of brachiocephalic artery was maintained using the chimney or in situ fenestration technique.

Results: Since August 2016, seven patients with aortic arch aneurysms underwent the procedure. The mortality rate was 0%. No neurological complications developed.

Conclusion: This brain protection method using selective cerebral perfusion under ECMO is a safe method for Zone 0 TEVAR.

Volatile and Intravenous Anesthetics for Brain Protection in Cardiac Surgery: Does the Choice of Anesthesia Matter?

Postoperative neurologic complications have a significant effect on morbidity, mortality, and long-term disability in patients undergoing cardiac surgery. The etiology of brain injury in patients undergoing cardiac surgery is multifactorial and remains unclear. There are several perioperative causative factors for neurologic complications, including microembolization, hypoperfusion, and systemic inflammatory response syndrome. Despite technologic advances and the development of new anesthetic drugs, there remains a high rate of postoperative neurologic complications. Moreover, despite the strong evidence that volatile anesthesia exerts cardioprotective effects in patients undergoing cardiac surgery, the neuroprotective effects of volatile agents remain unclear. Several studies have reported an association of using volatile anesthetics with improvement of biochemical markers of brain injury and postoperative neurocognitive function. However, there is a need for additional studies to define the optimal anesthetic drug for protecting the brain in patients undergoing cardiac surgery.

Efficient Iron and ROS Nanoscavengers for Brain Protection after Intracerebral Hemorrhage

Intracerebral hemorrhage (ICH) will be accompanied by the overload of iron and reactive oxygen species (ROS) following hematoma clearance. Although deferoxamine (DFO) has been widely utilized as a clinical first-line siderophore to remove the iron overload, the ROS-inducing damage still greatly limits the therapeutic effect of DFO. To address this issue, we designed and fabricated a series of dual-functional macromolecular nanoscavengers featuring high-density DFO units and catechol moieties. Note that the former units could effectively remove the iron overload, while the latter ones could efficiently deplete the ROS. The resulting nanoscavengers efficiently down-regulate the iron and ROS levels as well as significantly reduce the cell death in both iron-overloaded RAW 264.7 cells and the ICH mice model. This work suggests a novel clue for the ICH-ameliorated iron-depleting interventional therapeutic regimen.

Brain Protection in Aortic Arch Surgery: An Evolving Field

Despite advances in cardiac surgery and anesthesia, the rates of brain injury remain high in aortic arch surgery requiring circulatory arrest. The mechanisms of brain injury, including permanent and temporary neurologic dysfunction, are multifactorial, but intraoperative brain ischemia is likely a major contributor. Maintaining optimal cerebral perfusion during cardiopulmonary bypass and circulatory arrest is the key component of intraoperative management for aortic arch surgery. Various brain monitoring modalities provide different information to improve cerebral protection. Electroencephalography gives crucial data to ensure minimal cerebral metabolism during deep hypothermic circulatory arrest, transcranial Doppler directly measures cerebral arterial blood flow, and near-infrared spectroscopy monitors regional cerebral oxygen saturation. Various brain protection techniques, including hypothermia, cerebral perfusion, pharmacologic protection, and blood gas management, have been used during interruption of systemic circulation, but the optimal strategy remains elusive. Although deep hypothermic circulatory arrest and retrograde cerebral perfusion have their merits, there have been increasing reports about the use of antegrade cerebral perfusion, obviating the need for deep hypothermia. With controversy and variability of surgical practices, moderate hypothermia, when combined with unilateral antegrade cerebral perfusion, is considered safe for brain protection in aortic arch surgery performed with circulatory arrest. The neurologic outcomes of brain protection in aortic arch surgery largely depend on the following three major components: cerebral temperature, circulatory arrest time, and cerebral perfusion during circulatory arrest. The optimal brain protection strategy should be individualized based on comprehensive monitoring and stems from well-executed techniques that balance the major components contributing to brain injury.

Current status of open surgery for acute type A aortic dissection in Japan

OBJECTIVE

The study objective was to report the clinical outcomes of open surgery for acute aortic dissection by using the Japan Cardiovascular Database.

METHODS

Between 2013 and 2018, a total of 29,486 patients with acute aortic dissection who underwent open surgery were registered in the Japan Cardiovascular Database. Some 50% of patients were male. Age of patients at surgery was 59.8 ± 14.2 years; 61% of patients were aged less than 65 years, and 21% of patients were aged more than 75 years. Connective tissue disease was found in 1.2% of patients. Some 13% of patients had disturbed consciousness, and 12% of patients had cardiogenic shock. Some 11% of patients had moderate or severe aortic valve regurgitation, and 2.3% of patients had acute myocardial infarction. Some 94% of patients underwent surgery within 24 hours after diagnosis. Antegrade cerebral perfusion was used in 74% of patients, hypothermic circulatory arrest with retrograde cerebral perfusion was used in 17.1% of patients, and deep hypothermic circulatory arrest was used in 9.4% of patients. Cardiopulmonary bypass time was 216 ± 90 minutes, and cardiac ischemic time was 132 ± 60 minutes. Lowest body temperature was 24.6°C ± 3.2°C. Replacement of the ascending aorta (zone I) was performed in 69% of patients, and total arch replacement (zone 0 to zone II, III-) was performed in 29% of patients. The aortic valve was replaced in 7.9% of patients and repaired in 4.4% of patients.

RESULTS

The 30-day mortality was 9.2%, and in-hospital mortality was 11%. The number of operations has increased through the study periods. The in-hospital mortality has been stable or in a decreasing trend. Major complications consisted of stroke in 12% of patients, new hemodialysis in 7.3% of patients, spinal cord ischemia in 3.9% of patients, and prolonged ventilation in 15% of patients.

CONCLUSIONS

Approximately 30,000 patients with acute aortic dissection in the recent 6 years (2013 - 2018) underwent open surgery according to the nationwide Japanese database. The number of operations has increased, and in-hospital mortality has been stable or in a decreasing trend. Although the early outcomes are acceptable, there is still room for improvement in patients with preoperative comorbidities.

Does electroencephalographic burst suppression still play a role in the perioperative setting?

With the widespread use of electroencephalogram [EEG] monitoring during surgery or in the Intensive Care Unit [ICU], clinicians can sometimes face the pattern of burst suppression [BS]. The BS pattern corresponds to the continuous quasi-periodic alternation between high-voltage slow waves [the bursts] and periods of low voltage or even isoelectricity of the EEG signal [the suppression] and is extremely rare outside ICU and the operative room. BS can be secondary to increased anesthetic depth or a marker of cerebral damage, as a therapeutic endpoint [i.e., refractory status epilepticus or refractory intracranial hypertension]. In this review, we report the neurophysiological features of BS to better define its role during intraoperative and critical care settings.

Efficacy of acute administration of inhaled argon on traumatic brain injury in mice

BACKGROUND

Whilst there has been progress in supportive treatment for traumatic brain injury (TBI), specific neuroprotective interventions are lacking. Models of ischaemic heart and brain injury show the therapeutic potential of argon gas, but it is still not known whether inhaled argon (iAr) is protective in TBI. We tested the effects of acute administration of iAr on brain oedema, tissue micro-environmental changes, neurological functions, and structural outcome in a mouse model of TBI.

METHODS

Anaesthetised adult C57BL/6J mice were subjected to severe TBI by controlled cortical impact. Ten minutes after TBI, the mice were randomised to 24 h treatments with iAr 70%/O₂ 30% or air (iCtr). Sensorimotor deficits were evaluated up to 6 weeks post-TBI by three independent tests. Cognitive function was evaluated by Barnes maze test at 4 weeks. MRI was done to examine brain oedema at 3 days and white matter damage at 5 weeks. Microglia/macrophages activation and functional commitment were evaluated at 1 week after TBI by immunohistochemistry.

RESULTS

iAr significantly accelerated sensorimotor recovery and improved cognitive deficits 1 month after TBI, with less white matter damage in the ipsilateral fimbria and body of the corpus callosum. Early changes underpinning protection included a reduction of pericontusional vasogenic oedema and of the inflammatory response. iAr significantly reduced microglial activation with increases in ramified cells and the M2-like marker YM1.

CONCLUSIONS

iAr accelerates recovery of sensorimotor function and improves cognitive and structural outcome 1 month after severe TBI in adult mice. Early effects include a reduction of brain oedema and neuroinflammation in the contused tissue.

Endogenous brain-sparing responses in brain pH and PO2 in a rodent model of birth asphyxia

AIM

To study brain-sparing physiological responses in a rodent model of birth asphyxia which reproduces the asphyxia-defining systemic hypoxia and hypercapnia.

METHODS

Steady or intermittent asphyxia was induced for 15-45 minutes in anaesthetized 6- and 11-days old rats and neonatal guinea pigs using gases containing 5% or 9% O₂ plus 20% CO₂ (in N₂ ). Hypoxia and hypercapnia were induced with low O₂ and high CO₂ respectively. Oxygen partial pressure (PO₂ ) and pH were measured with microsensors within the brain and subcutaneous ("body") tissue. Blood lactate was measured after asphyxia.

RESULTS

Brain and body PO₂ fell to apparent zero with little recovery during 5% O₂ asphyxia and 5% or 9% O₂ hypoxia, and increased more than twofold during 20% CO₂ hypercapnia. Unlike body PO₂ , brain PO₂ recovered rapidly to control after a transient fall (rat), or was slightly higher than control (guinea pig) during 9% O₂ asphyxia. Asphyxia (5% O₂ ) induced a respiratory acidosis paralleled by a progressive metabolic (lact)acidosis that was much smaller within than outside the brain. Hypoxia (5% O₂ ) produced a brain-confined alkalosis. Hypercapnia outlasting asphyxia suppressed pH recovery and prolonged the post-asphyxia PO₂ overshoot. All pH changes were accompanied by consistent shifts in the blood-brain barrier potential.

CONCLUSION

Regardless of brain maturation stage, hypercapnia can restore brain PO₂ and protect the brain against metabolic acidosis despite compromised oxygen availability during asphyxia. This effect extends to the recovery phase if normocapnia is restored slowly, and it is absent during hypoxia, demonstrating that exposure to hypoxia does not mimic asphyxia.

Vascular Endothelial Cell-derived Exosomes Protect Neural Stem Cells Against Ischemia/reperfusion Injury

Vascular endothelial cells were activated during acute ischemic brain injury, which could induce neural progenitor cell proliferation and migration. However, the mechanism was still unknown. In the current study, we explored whether vascular endothelial cells promoted neural progenitor cell proliferation and whether migration occurs via exosome communication. The acute middle cerebral artery occlusion (MCAO) model was prepared, and exosomes were isolated from bEnd.3 cells by ultracentrifugation. In the exosome injection (Exos) group and PBS injection (control) group, exosomes or PBS were injected intraventricularly into rats' brains 2 h after MCAO surgery, respectively. Sham group rats received the same surgical but did not cause middle cerebral artery occlusion. The infarct volume was reduced on day 21 after ischemic brain injury by MRI, and neurobehavioral outcomes were improved on day 7, 14, and 21 by exosome injection compared with the control (p < 0.05). On the 21st day after MCAO, the animals were euthanized, and the number of BrdU/nestin-positive cells was measured by immunofluorescence. BrdU/nestin-positive cells in Exos group rats were significantly increased (p < 0.05) in the peri infarct area, the ipsilateral DG zone of the hippocampus, and the ventral sub-regions of SVZ when compared with the rats in the control group. Further, in vitro study demonstrated that neural progenitor cell proliferation and migration were activated after exosomes treatment, and cell apoptosis was attenuated compared to the control (p < 0.05). Our study suggested that exosomes should be essential for the reconstruction of neuronal vascular units and brain protection in an acute ischemic injured brain.

Central neuroprotection demonstrated by novel oxime countermeasures to nerve agent surrogates

Oximes remain a long-standing element of the therapy for nerve agents, organophosphates (OPs) that poison by inhibiting the enzyme acetylcholinesterase (AChE), resulting in hypercholinergic activity both centrally and peripherally. Oximes, such as the pyridinium oxime pralidoxime (2-PAM) in the United States, can reactivate the inhibited AChE and restore cholinergic function. However, there are several drawbacks to the current oximes; one of them, the inability of these oximes to effectively enter the brain, is the subject of study by several laboratories, including ours. Our laboratory invented a platform of substituted phenoxyalkyl pyridinium oximes that were tested against highly relevant surrogates of the nerve agents, sarin and VX. Using high sublethal dosages of the OPs, the novel oximes were observed to attenuate seizure-like behavior in rats and to reduce the levels of glial fibrillary acidic protein (an indicator of glial scarring) to control levels, in contrast to levels observed with 2-PAM or no oxime therapy. Using lethal levels of surrogates, some novel oximes protected against lethality compared with 2-PAM, shortened the time to cessation of seizure-like behavior (from 8+ to 6 h), and protected the brain neurons. Therefore, some of these novel oximes are showing exceptional promise alone or in combination with 2-PAM as therapeutics against nerve agent toxicity.

Liraglutide Protects Against Brain Amyloid-β1-42 Accumulation in Female Mice with Early Alzheimer's Disease-Like Pathology by Partially Rescuing Oxidative/Nitrosative Stress and Inflammation

Alzheimer’s disease (AD) is the most common form of dementia worldwide, being characterized by the deposition of senile plaques, neurofibrillary tangles (enriched in the amyloid beta (Aβ) peptide and hyperphosphorylated tau (p-tau), respectively) and memory loss. Aging, type 2 diabetes (T2D) and female sex (especially after menopause) are risk factors for AD, but their crosslinking mechanisms remain unclear. Most clinical trials targeting AD neuropathology failed and it remains incurable. However, evidence suggests that effective anti-T2D drugs, such as the GLP-1 mimetic and neuroprotector liraglutide, can be also efficient against AD. Thus, we aimed to study the benefits of a peripheral liraglutide treatment in AD female mice. We used blood and brain cortical lysates from 10-month-old 3xTg-AD female mice, treated for 28 days with liraglutide (0.2 mg/kg, once/day) to evaluate parameters affected in AD (e.g., Aβ and p-tau, motor and cognitive function, glucose metabolism, inflammation and oxidative/nitrosative stress). Despite the limited signs of cognitive changes in mature female mice, liraglutide only reduced their cortical Aβ_1–42 levels. Liraglutide partially attenuated brain estradiol and GLP-1 and activated PKA levels, oxidative/nitrosative stress and inflammation in these AD female mice. Our results support the earlier use of liraglutide as a potential preventive/therapeutic agent against the accumulation of the first neuropathological features of AD in females.

Effects of eplerenone on cerebral aldosterone levels and brain lesions in spontaneously hypertensive rats

Evidence indicates that renin-angiotensin-aldosterone system (RAS) inhibitors can protect the brain in Alzheimer's disease and Parkinson's disease. The current study evaluated the relationship between aldosterone and tissue damage in the brains of spontaneously hypertensive rats (SHRs) and whether the RAS inhibitor eplerenone can mitigate the damage seen in these rats. SHRs were randomly divided into eplerenone (n = 10) and SHR (n = 10) groups, and Wistar-Kyoto (WKY) rats (n = 10) were used as controls. Eplerenone 50 mg/kg/day was administered orally to the eplerenone group. Pathological changes to the hippocampal formation, plasma and encephalic aldosterone, and plasma potassium levels were compared among the groups. After 10 weeks, rats in the eplerenone and SHR groups showed higher systolic BP (p = .01) than the control group. Aldosterone levels in the brain were higher in the SHR group (0.20 ± 0.06 pg/ml) than in the eplerenone (0.14 ± 0.05 pg/ml, p = .044) or control (0.12 ± 0.07 pg/ml, p = .007) groups. Plasma aldosterone levels in the SHR group were 1.7 times higher than those in the control group (p = .006). Cerebral cortex was thinner in the SHR group (225.18 ± 15.43 μm) than in the eplerenone (240.38 ± 12.85 μm, p < .01) or control (244.72 ± 18.92 μm, p < .01) groups. Thickness did not differ between the latter two groups. The SHR group exhibited apoptotic cells in the hippocampal formation, which were rare in the eplerenone and control groups. Plasma potassium levels were higher in the eplerenone group than those in the other two groups (p < .05). Our results showed that eplerenone can alleviate brain damage (thinning of cortex and increased apoptosis) caused by aldosterone in a rat model of hypertension.

Dexmedetomidine Exerts Brain-Protective Effects Under Cardiopulmonary Bypass Through Inhibiting the Janus Kinase 2/Signal Transducers and Activators of Transcription 3 Pathway

Brain injury is a major complication resulted from cardiopulmonary bypass (CPB). Dexmedetomidine (DEX) has potential brain-protective effects; however, the mechanism is unclear. The aim of this study is to investigate the effect of DEX on brain injury in CPB rats and its mechanism. The levels of interleukin-6 (IL-6), interleukin-10 (IL-10), S100β, and neuron-specific enolase (NSE) were measured by enzyme-linked immunosorbent assay. The hippocampus CA1 region in rats was observed by hematoxylin-eosin staining. Western blot and quantitative real-time polymerase chain reaction were performed to detect related proteins and mRNA expressions in the hippocampus tissues. We found that after CPB, the neuron cells in hippocampus CA1 region of rats were randomly arranged, and that the levels of IL-6, IL-10, S100β, NSE, Cleaved Caspase-3, and Bax were upregulated, while Bal-2 level was downregulated. However, after DEX treatment, the neuron cells arranged in an orderly manner, and the levels of IL-6, IL-10, S100β, NSE, Cleaved Caspase-3, and Bax were downregulated, but Bal-2 level was upregulated. DEX suppressed Janus kinase 2 (JAK2)/signal transducers and activators of transcription 3 (STAT3) pathway activated by CPB, ameliorated CPB-induced brain injury in rats by reducing inflammatory response, and inhibited neuronal apoptosis. The brain-protective effect of DEX may be related to the inhibition of the activation of JAK2/STAT3 pathway.

Progress of Research on Exosomes in the Protection Against Ischemic Brain Injury

Exosomes, as a type of extracellular vesicle (EV), are lipid bilayer vesicles 20–100 nm in diameter that can cross the blood-brain barrier. Exosomes are important transport vesicles in the human body that participate in many conduction pathways and play an important physiological role. Because of their high biocompatibility and low immunogenicity and toxicity, exosomes have attracted increasing attention as an attractive drug delivery system. This article reviews the relevant studies that have shown that exosomes play an important role in protective mechanisms against ischemic brain injury.

Systemic L-Buthionine -S-R-Sulfoximine Treatment Increases Plasma NGF and Upregulates L-cys/L-cys2 Transporter and γ-Glutamylcysteine Ligase mRNAs Through the NGF/TrkA/Akt/Nrf2 Pathway in the Striatum

Glutathione (GSH) is the most abundant intracellular antioxidant. GSH depletion leads to oxidative stress and neuronal damage in the central nervous system (CNS). In mice, the acute systemic inhibition of GSH synthesis by L-buthionine-S-R-sulfoximine (BSO) triggers a protective response and a subsequent increase in the CNS GSH content. This response might be modulated by a peripheral increment of circulating nerve growth factor (NGF). NGF is an important activator of antioxidant pathways mediated by tropomyosin-related kinase receptor A (TrkA). Here, we report that peripheral administration of BSO increased plasma NGF levels. Additionally, BSO increased NGF levels and activated the NGF/TrkA/Akt pathway in striatal neurons. Moreover, the response in the striatum included an increased transcription of nrf2, gclm, lat1, eaac1, and xct, all of which are involved in antioxidant responses, and L-cys/L-cys₂ and glutamate transporters. Using antibody against NGF confirmed that peripheral NGF activated the NGF/TrkA/Akt/Nrf2 pathway in the striatum and subsequently increased the transcription of gclm, nrf2, lat1, eaac1, and xct. These results provide evidence that the reduction of peripheral GSH pools increases peripheral NGF circulation that orchestrates a neuroprotective response in the CNS, at least in the striatum, through the NGF/TrkA/Akt/Nrf2 pathway.

Debranching-first and proximal arch replacement for an innominate artery aneurysm: a case study

The aneurysms of the innominate artery represent a rare form of aneurysmal disease. Management in an early elective basis is recommended due to the risk of stroke and rupture. Treatment options include open surgery, which is the gold standard, and endovascular repair. We describe the debranching-first technique and proximal arch replacement for a huge innominate artery aneurysm and discuss the surgical strategy for cannulation, perfusion and organ protection.

Evaluation of the clinical usage of the basket-shaped biopsy microseparator

Objective

This experimental study was aimed to assess the use of basket shaped biopsy microseparator. In this study, it was aimed to evaluate the protection of brain tissue during neurosurgery of the brain tissue, clinical usage, and suitability.

Materials and Methods

Thirty cadaveric cow brains were used in this experimental feasibility study. Experimental materials were divided into two groups: In Group I, the microsurgical separation of the intrinsic brain parenchyma was performed by using the retraction of microsurgical basket separator. In Group II, the same microsurgical dissections were performed without microsurgical basket separator. The difficulty and suitability of the procedure was divided as three degree: very easy, easy, and difficult.

Results

In Group I (n = 30), 20% fresh cadaveric cow brains, the difficulty of the dissection was evaluated as difficult; 60% of the brains were dissected with easy procedure. The remaining 20% of the brain dissection was evaluated as very easy. In Group II (n = 30), 40% fresh cadaveric cow brains, the difficulty of the dissection was evaluated as difficult; 53.33% of the brains were dissected with easy procedure. The remaining 6.67% of the brains were evaluated as very easy. The significance level was set at a P value of <0.046 in all statistical analyses.

Conclusion

This study showed that easily performing biopsy procedure and protecting the brain tissue with using of biopsy basket microseparator are feasible. It is thought that this instrument may make a contribution to the practical microsurgery in the protecting brain tissue and adequately performing of biopsy.

Neuroprotection in Traumatic Brain Injury: Mesenchymal Stromal Cells can Potentially Overcome Some Limitations of Previous Clinical Trials

Traumatic brain injury (TBI) is a leading cause of death and disability worldwide. In the last 30 years several neuroprotective agents, attenuating the downstream molecular and cellular damaging events triggered by TBI, have been extensively studied. Even though many drugs have shown promising results in the pre-clinical stage, all have failed in large clinical trials. Mesenchymal stromal cells (MSCs) may offer a promising new therapeutic intervention, with preclinical data showing protection of the injured brain. We selected three of the critical aspects identified as possible causes of clinical failure: the window of opportunity for drug administration, the double-edged contribution of mechanisms to damage and recovery, and the oft-neglected role of reparative mechanisms. For each aspect, we briefly summarized the limitations of previous trials and the potential advantages of a newer approach using MSCs.

Neuro-protection in open arch surgery

Although antegrade cerebral perfusion (ACP) is the predominant method of protecting the brain in patients undergoing total arch replacement, both deep hypothermic circulatory arrest and ACP provide excellent and comparable clinical outcomes with regard to mortality, stroke, and temporary neurological deficit rates.

Effects of 4 major brain protection strategies during aortic arch surgery: A protocol for a systematic review and network meta-analysis using Stata

BACKGROUND

Reliable brain protection during aortic arch surgery remains a formidable surgical challenge. Various cerebral protection techniques have been used in the clinic; however, there is no consensus regarding which strategy is best. We will perform a network meta-analysis (NMA) focusing on the permanent neurological deficits (PND) and perioperative mortality associated with 4 major brain protection strategies used during aortic arch surgery.

METHODS

We will perform a literature search of MEDLINE, EMBASE, Cochrane Library, and PubMed databases. The primary outcomes of interest in this analysis will be PND and perioperative mortality. Inconsistencies in the NMA will be evaluated with global and local approaches. Network rank and surface under the cumulative ranking curve (SUCRA) analyses will be performed to evaluate and identify the superiority of different brain protection techniques.

RESULTS

This study is ongoing and will be submitted to a peer-reviewed journal for consideration of publication.

CONCLUSIONS

Our study will increase understanding of 4 major brain protection strategies during aortic arch surgery and be helpful to clinicians using NMA in their studies.

Virtual Reality for Traumatic Brain Injury

In this perspective, we discuss the potential of virtual reality (VR) in the assessment and rehabilitation of traumatic brain injury, a silent epidemic of extremely high burden and no pharmacological therapy available. VR, endorsed by the mobile and gaming industries, is now available in more usable and cheaper tools allowing its therapeutic engagement both at the bedside and during the daily life at chronic stages after injury with terrific potential for a longitudinal disease modifying effect.

Protecting the brain and spinal cord in aortic arch surgery

Protection of the central nervous system-either the brain or the spinal cord-during aortic surgery has been the subject of intense research over the past several decades. While it took some 30 years to prove that some of the techniques first practiced in animals are valuable, surgeons can now take courage from 50 years of research that has resulted in superb outcomes, particularly when compared with historical results. Complex total arch operations and descending aortic operations can now be performed with less than a 2% rate of stroke, spinal cord injury, or death. Thoracoabdominal aortic operations and endovascular procedures have also become considerably safer with excellent results reported. The following review will discuss some of the historical outcomes, innovations, iterations, current techniques, and outcomes.

Cerebral perfusion issues in type A aortic dissection

Stroke events are very common in acute type A aortic dissection. Cerebral malperfusion could manifest at presentation due to prolonged arch vessels hypoperfusion or develop after surgery for inadequate cerebral protection during arch repair. To reduce this detrimental complication there are several adjuncts that can be adopted for cerebral protection such as direct antegrade or retrograde cerebral perfusion (RCP) and use period of deep to moderate hypothermic circulatory arrest time; however, they are often insufficient as preoperative malperfusion already caused irreversible ischemic damages. The aim of the current review article is to analyze the principal series reporting on neurological injuries during type A aortic dissection to focus on the outcomes according to the type of surgical management and identify possible predictors to better manage this complication.

Exogenous brain-derived neurotrophic factor attenuates cognitive impairment induced by okadaic acid in a rat model of Alzheimer's disease

Decreased expression of brain-derived neurotrophic factor (BDNF) plays an important role in the pathogenesis of Alzheimer's disease, and a typical pathological change in Alzheimer's disease is neurofibrillary tangles caused by hyperphosphorylation of tau. An in vivo model of Alzheimer's disease was developed by injecting okadaic acid (2 μL) and exogenous BDNF (2 μL) into the hippocampi of adult male Wister rats. Spatial learning and memory abilities were assessed using the Morris water maze. The expression levels of protein phosphatase 2A (PP2A), PP2Ac-Yp307, p-tau (Thr231), and p-tau (Ser396/404) were detected by western blot assay. The expression levels of BDNF, TrkB, and synaptophysin mRNA were measured by quantitative real-time polymerase chain reaction. Our results indicated that BDNF expression was suppressed in the hippocampus of OA-treated rats, which resulted in learning and memory deficits. Intra-hippocampal injection of BDNF attenuated this OA-induced cognitive impairment. Finally, our findings indicated an involvement of the PI3K/GSK-3β/AKT pathway in the mechanism of BDNF in regulating cognitive function. These results indicate that BDNF has beneficial effect on Alzheimer's disease, and highlight the potential of BDNF as a drug target for treatment of Alzheimer's disease.

Protective Effects of Japanese Soybean Paste (Miso) on Stroke in Stroke-Prone Spontaneously Hypertensive Rats (SHRSP)

BACKGROUND AND HYPOSESIS

Soybean isoflavones have been shown to reduce the risk of cerebral infarction in humans according to epidemiological studies. However, whether intake of miso can reduce the incidence of stroke in animal models remains unknown. In this study, we investigated the effects of soybean paste (miso) in an animal model of stroke.

METHODS

Stroke-prone spontaneously hypertensive rats (SHRSP) were fed a miso diet (normal diet 90%, miso 10%; final NaCl content 2.8%), a high salt diet (normal diet and NaCl 2.5%; final NaCl content 2.8%), or a low salt diet (normal diet; final NaCl content 0.3%).

RESULTS

Kaplan-Meier survival curves revealed a significantly lower survival rate in the high salt group compared to the miso group (P = 0.002) and the low salt group (P ≤ 0.001). Large hemorrhagic macules were found in the cerebrum in the high salt group, whereas none were found in the other 2 groups. There were also fewer histological and immunohistochemical changes in the brain and kidneys in the miso group compared to the high salt group.

CONCLUSION

Our results suggest that miso may have protective effects against stroke despite its high salt content.

The Risk of Neurological Dysfunctions after Deep Hypothermic Circulatory Arrest with Retrograde Cerebral Perfusion

OBJECTIVE

Retrograde cerebral perfusion (RCP) is a brain protection technique that is adopted generally for anticipated short periods of deep hypothermic circulatory arrest (DHCA). However, the real impact of this technique on cerebral protection during DHCA remains a controversial issue.

METHODS

For 344 (59.5%) of 578 consecutive patients (mean age, 66.9 ± 10.9 years) who underwent cardiovascular surgery under DHCA at the present authors' institution (1999-2015), RCP was the sole technique of cerebral protection that was adopted in addition to deep hypothermia. Surgery of the thoracic aorta was performed in 95.9% of these RCP patients; in 92 cases there was an aortic arch involvement. Outcomes were reviewed retrospectively. The focus was on postoperative neurological dysfunctions.

RESULTS

There were 33 (9.6%) in-hospital deaths. Thirty-one (9%) patients had permanent neurological dysfunctions and 66 (19.1%) transitory neurological dysfunctions alone. Age older than 74 years (odds ratio [OR], 1.88, P = .023), surgery for acute aortic dissection (OR, 2.57; P = .0009), and DHCA time longer than 25 minutes (OR, 2.44; P = .0021) were predictors of neurological dysfunctions. The 10-year nonparametric estimate of freedom from all-cause death was 61.8% (95% confidence interval, 57.8%-65.8%). Permanent postoperative neurological dysfunctions were risk factors for cardiac or cerebrovascular death (hazard ratio, 2.6; P = .039) even after an adjusted survival analysis (P < .04).

CONCLUSIONS

According to the study findings, RCP, in addition to deep hypothermia, combines with a low risk of neurological dysfunctions provided that DHCA length is 25 minutes or less. Permanent postoperative neurological dysfunctions are predictors of poor late survival.

Therapeutic Strategies to Attenuate Hemorrhagic Transformation After Tissue Plasminogen Activator Treatment for Acute Ischemic Stroke

This review focuses on the mechanisms and emerging concepts of stroke and therapeutic strategies for attenuating hemorrhagic transformation (HT) after tissue plasminogen activator (tPA) treatment for acute ischemic stroke (AIS). The therapeutic time window for tPA treatment has been extended. However, the patients who are eligible for tPA treatment are still ＜5% of all patients with AIS. The risk of serious or fatal symptomatic hemorrhage increases with delayed initiation of treatment. HT is thought to be caused by 1) ischemia/reperfusion injury; 2) the toxicity of tPA itself; 3) inflammation; and/or 4) remodeling factor-mediated effects. Modulation of these pathophysiologies is the basis of direct therapeutic strategies to attenuate HT after tPA treatment. Several studies have revealed that matrix metalloproteinases and free radicals are potential therapeutic targets. In addition, we have demonstrated that the inhibition of the vascular endothelial growth factor-signaling pathway and supplemental treatment with a recombinant angiopoietin-1 protein might be a promising therapeutic strategy for attenuating HT after tPA treatment through vascular protection. Moreover, single-target therapies could be insufficient for attenuating HT after tPA treatment and improving the therapeutic outcome of patients with AIS. We recently identified progranulin, which is a growth factor and a novel target molecule with multiple therapeutic effects. Progranulin might be a therapeutic target that protects the brain through suppression of vascular remodeling (vascular protection), neuroinflammation, and/or neuronal death (neuroprotection). Clinical trials which evaluate the effects of anti-VEGF drugs or PGRN-based treatment with tPA will be might worthwhile.

Aortic arch reconstruction: deep and moderate hypothermic circulatory arrest with selective antegrade cerebral perfusion

OBJECTIVE

To compare the effects of moderate and deep hypothermic circulatory arrest (DHCA) with selective antegrade cerebral perfusion (SACP) during aortic arch surgery in adult patients and to offer the evidence for the detection of the temperature which provides best brain protection in the subjects who accept aortic arch reconstruction surgery.

METHODS

A total of 109 patients undergoing surgery of the aortic arch were divided into the moderate hypothermic circulatory arrest group (Group I) and the deep hypothermic circulatory arrest group (Group II). We recorded the data of the patients and their cardiopulmonary bypass (CPB) time, aortic clamping time, SACP time and postoperative anesthetized recovery time, tracheal intubation time, time in the intensive care unit (ICU) and postoperative neurologic dysfunction.

RESULTS

Patient characteristics were similar in the two groups. There were four patients who died in Group II and 1 patient in Group I. There were no significant differences in aortic clamping time of each group (111.4±58.4 vs. 115.9±16.2) min; SACP time (27.4±5.9 vs. 23.5±6.1) min of the moderate hypothermic circulatory arrest group and the deep hypothermic circulatory arrest group; there were significant differences in cardiopulmonary bypass time (207.4±20.9 vs. 263.8±22.6) min, postoperative anesthetized recovery time (19.0±11.1 vs. 36.8±25.3) hours, extubation time (46.4±15.1 vs. 64.4±6.0) hours; length of stay in the intensive care unit (ICU) (4.7±1.7 vs. 8±2.3) days and postoperative neurologic dysfunction in the two groups.

CONCLUSION

Compared to deep hypothermic circulatory arrest, moderate hypothermic circulatory arrest can provide better brain protection and achieve good clinical results.

Implications from neurologic assessment of brain protection for total arch replacement from a randomized trial

OBJECTIVE

The study objective was to perform a randomized trial of brain protection during total aortic arch replacement and identify the best way to assess brain injury.

METHODS

From June 2003 to January 2010, 121 evaluable patients were randomized to retrograde (n = 60) or antegrade (n = 61) brain perfusion during hypothermic circulatory arrest. We assessed the sensitivity of clinical neurologic evaluation, brain imaging, and neurocognitive testing performed preoperatively and 4 to 6 months postoperatively to detect brain injury.

RESULTS

A total of 29 patients (24%) experienced neurologic events. Clinical stroke was evident in 1 patient (0.8%), and visual changes were evident in 2 patients; all had brain imaging changes. A total of 14 of 95 patients (15%) undergoing both preoperative and postoperative brain imaging had evidence of new white or gray matter changes; 10 of the 14 patients had neurocognitive testing, but only 2 patients experienced decline. A total of 17 of 96 patients (18%) undergoing both preoperative and postoperative neurocognitive testing manifested declines of 2 or more reliable change indexes; of these 17, 11 had neither imaging changes nor clinical events. Thirty-day mortality was 0.8% (1/121), with no neurologic deaths and a similar prevalence of neurologic events after retrograde and antegrade brain perfusion (22/60, 37% and 15/61, 25%, respectively; P = .2).

CONCLUSIONS

Although this randomized clinical trial revealed similar neurologic outcomes after retrograde or antegrade brain perfusion for total aortic arch replacement, clinical examination for postprocedural neurologic events is insensitive, brain imaging detects more events, and neurocognitive testing detects even more. Future neurologic assessments for cardiovascular procedures should include not only clinical examination but also brain imaging studies, neurocognitive testing, and long-term assessment.

A reappraisal of retrograde cerebral perfusion

Brain protection during aortic arch surgery by perfusing cold oxygenated blood into the superior vena cava was first reported by Lemole et al. In 1990 Ueda and associates first described the routine use of continuous retrograde cerebral perfusion (RCP) in thoracic aortic surgery for the purpose of cerebral protection during the interval of obligatory interruption of anterograde cerebral flow. The beneficial effects of RCP may be its ability to sustain brain hypothermia during hypothermic circulatory arrest (HCA) and removal of embolic material from the arterial circulation of the brain. RCP can offer effective brain protection during HCA for about 40 to 60 minutes. Animal experiments revealed that RCP provided inadequate cerebral perfusion and that neurological recovery was improved with selective antegrade cerebral perfusion (ACP), however, both RCP and ACP provide comparable clinical outcomes regarding both the mortality and stroke rates by risk-adjusted and case-matched comparative study. RCP still remains a valuable adjunct for brain protection during aortic arch repair in particular pathologies and patients.

Research studies that have influenced practice of neuroanesthesiology in recent years: A literature review

Through evolving research, recent years have witnessed remarkable achievements in neuromonitoring and neuroanesthetic techniques, with a huge body of literature consisting of excellent studies in neuroanaesthesiology. However, little of this work appears to be directly important to clinical practice. Many controversies still exist in care of patients with neurologic injury. This review discusses studies of great clinical importance carried out in the last five years, which have the potential of influencing our current clinical practice and also attempts to define areas in need of further research. Relevant literature was obtained through multiple sources that included professional websites, medical journals and textbooks using key words “neuroanaesthesiology,” “traumatic brain injury,” “aneurysmal subarachnoid haemorrhage,” “carotid artery disease,” “brain protection,” “glycemic management” and “neurocritical care.” In head injured patients, administration of colloid and pre-hospital hypertonic saline resuscitation have not been found beneficial while use of multimodality monitoring, individualized optimal cerebral perfusion pressure therapy, tranexamic acid and decompressive craniectomy needs further evaluation. Studies are underway for establishing cerebroprotective potential of therapeutic hypothermia. Local anaesthesia provides better neurocognitive outcome in patients undergoing carotid endarterectomy compared with general anaesthesia. In patients with aneurysmal subarachnoid haemorrhage, induced hypertension alone is currently recommended for treating suspected cerebral vasospasm in place of triple H therapy. Till date, nimodipine is the only drug with proven efficacy in preventing cerebral vasospasm. In neurocritically ill patients, intensive insulin therapy results in substantial increase in hypoglycemic episodes and mortality rate, with current emphasis on minimizing glucose variability. Results of ongoing multicentric trials are likely to further improvise our practice.

Strategies to improve recovery in acute ischemic stroke patients: Iberoamerican Stroke Group Consensus

Stroke is not only a leading cause of death worldwide but also a main cause of disability. In developing countries, its burden is increasing as a consequence of a higher life expectancy. Whereas stroke mortality has decreased in developed countries, in Latin America, stroke mortality rates continue to rise as well as its socioeconomic dramatic consequences. Therefore, it is necessary to implement stroke care and surveillance programs to better describe the epidemiology of stroke in these countries in order to improve therapeutic strategies. Advances in the understanding of the pathogenic processes of brain ischemia have resulted in development of effective therapies during the acute phase. These include reperfusion therapies (both intravenous thrombolysis and interventional endovascular approaches) and treatment in stroke units that, through application of management protocols directed to maintain homeostasis and avoid complications, helps to exert effective brain protection that decreases further cerebral damage. Some drugs may enhance protection, and besides, there is increasing knowledge about brain plasticity and repair mechanisms that take place for longer periods beyond the acute phase. These mechanisms are responsible for recovery in certain patients and are the focus of basic and clinical research at present. This paper discusses recovery strategies that have demonstrated clinical effect, or that are promising and need further study. This rapidly evolving field needs to be carefully and critically evaluated so that investment in patient care is grounded on well-proven strategies.

Excitatory amino acid changes in the brains of rhesus monkeys following selective cerebral deep hypothermia and blood flow occlusion

Selective cerebral deep hypothermia and blood flow occlusion can enhance brain tolerance to ischemia and hypoxia and reduce cardiopulmonary complications in monkeys. Excitotoxicity induced by the release of a large amount of excitatory amino acids after cerebral ischemia is the major mechanism underlying ischemic brain injury and nerve cell death. In the present study, we used selective cerebral deep hypothermia and blood flow occlusion to block the bilateral common carotid arteries and/or bilateral vertebral arteries in rhesus monkey, followed by reperfusion using Ringer's solution at 4°C. Microdialysis and transmission electron microscope results showed that selective cerebral deep hypothermia and blood flow occlusion inhibited the release of glutamic acid into the extracellular fluid in the brain frontal lobe and relieved pathological injury in terms of the ultrastructure of brain tissues after severe cerebral ischemia. These findings indicate that cerebral deep hypothermia and blood flow occlusion can inhibit cytotoxic effects and attenuate ischemic/hypoxic brain injury through decreasing the release of excitatory amino acids, such as glutamic acid.