Transcriptomics and Metabolomics Unveil the Neuroprotection Mechanism of AnGong NiuHuang (AGNH) Pill Against Ischaemic Stroke Injury

As a famous prescription in China, AnGong NiuHuang (AGNH) pill exerts good neuroprotection for ischaemic stroke (IS), but its mechanism is still unclear. In this study, the neuroprotection of AGNH was evaluated in the rat IS model which were established with the surgery of middle cerebral artery occlusion (MCAO), and the potential mechanism was elucidated by transcriptomic analysis and metabolomic analysis. AGNH treatment obviously decreased the infarct volume and Zea-Longa 5-point neurological deficit scores, improved the survival percentage of rats, regional cerebral blood flow (rCBF), and rat activity distance and activity time. Transcriptomics showed that AGNH exerted its anti-inflammatory effects by affecting the regulatory network including Tyrobp, Syk, Tlr2, Myd88 and Ccl2 as the core. Integrating transcriptomics and metabolomics identified 8 key metabolites regulated by AGNH, including L-histidine, L-serine, L-alanine, fumaric acid, malic acid, and N-(L-arginino) succinate, 1-pyrroline-4-hydroxy-2-carboxylate and 1-methylhistamine in the rats with IS. Additionally, AGNH obviously reduced Tyrobp, Syk, Tlr2, Myd88 and Ccl2 at both the mRNA and protein levels, decreased IL-1β, KC-GRO, IL-13, TNF-α, cleaved caspase 3 and p65 nucleus translocation, but increased IκBα expression. Network pharmacology analysis showed that quercetin, beta-sitosterol, baicalein, naringenin, acacetin, berberine and palmatine may play an important role in protecting against IS. Taken together, this study reveals that AGNH reduced neuroinflammation and protected against IS by inhibiting Tyrobp/Syk and Tlr2/Myd88, as well as NF-κB signalling pathway and regulating multiple metabolites.

Quercetin attenuates cerebral ischemic injury by inhibiting ferroptosis via Nrf2/HO-1 signaling pathway

AIMS

Ischemic stroke is a severe cerebrovascular disease in which neuronal death continually occurs through multiple forms, including apoptosis, autophagy, pyroptosis and ferroptosis. Quercetin (QRC), as a natural flavonoid compound, has been reported to have pharmacological effects on ischemic injury accompanied by unclear anti-ferroptotic mechanisms. This study is designed to investigate the therapeutic effects of QRC against ferroptosis in ischemic stroke.

MATERIALS AND METHODS

In vivo, the model of MCAO rats were used to assess the protective effect of QRC on cerebral ischemic. Additionally, we constructed oxidative stressed and ferroptotic cell models to explore the effects and mechanisms of QRC on ferroptosis. The related proteins were analysed by western blotting, immunohistochemical and immunofluorescence techniques.

RESULTS

The experiments demonstrated that QRC improves neurological deficits, infarct volume, and pathological features in MCAO rats, also increased the viability of HT-22 cells exposed to H2O2 and erastin. These results, including MDA, SOD, GSH, ROS levels and iron accumulation, indicated that QRC suppresses the generation of lipid peroxides and may involve in the regulatory of ferroptosis. Both in vitro and in vivo, QRC was found to inhibit ferroptosis by up-regulating GPX4 and FTH1, as well as down-regulating ACSL4. Furthermore, we observed that QRC enhances the nuclear translocation of Nrf2 and activates the downstream antioxidative proteins. Importantly, the effect of QRC on ferroptosis can be reversed by the Nrf2 inhibitor ML385.

CONCLUSIONS

This study provides evidence that QRC has a neuroprotective effect by inhibiting ferroptosis, demonstrating the therapeutic potential for cerebral ischemic stroke.

Effects of combined electroacupuncture and medication therapy on the RhoA/ROCK-2 signaling pathway in the striatal region of rats afflicted by cerebral ischemia

OBJECTIVE

To investigate the effects of electroacupuncture(EA), gastrodin(Gas), and their combination on the signaling pathways involving Ras homologous gene family member A (RhoA) and Rho-associated frizzled helix protein kinase (ROCK-2) within the striatal region of rats subjected to cerebral ischemia. Additionally, we aim to elucidate the therapeutic effects and potential underlying mechanisms associated with the concurrent application of electroacupuncture and medication in the treatment of cerebral ischemia.

METHODS

Rats were randomly assigned to one of five groups, namely, the sham operation (Sham) group, model group, EA group, Gas group, and the EA combined with Gas group (referred to as the "EA+Gas group"). Each group consisted of ten rats. Following the induction of cerebral ischemia, the EA group and EA+Gas group received EA stimulation at the Baihui(GV20) and Zusanli(ST36) acupoints for 30 min per session, administered once daily for 14 consecutive days. The Gas group and EA+Gas group were intraperitoneally injected with Gas at a dosage of 10 mg/kg, also administered once daily for 14 consecutive days. Nissl staining was employed to observe morphological alterations in the striatal nerve cells of rats in each group. Immunohistochemistry and western blot techniques were employed to evaluate the expression levels of striatal RhoA and ROCK-2 proteins.

RESULTS

In comparison to the Sham group, the model group exhibited a substantial reduction in the number of striatal nerve cells on the ischemic side, accompanied by notable changes in cell morphology, characterized by reduced cytoplasm, defective and atrophied cytosol, solidified nuclei, loosely arranged cells, and enlarged intercellular spaces. Additionally, there was a notable increase in the positive expression of RhoA and ROCK-2. In contrast, when compared to the model group, the EA, Gas, and EA+Gas groups demonstrated an elevated number of normal nerve cells within the ischemic striatal region, with a significant improvement in cell count and morphology. Furthermore, positive expression levels of RhoA and ROCK-2 were notably reduced in these groups. Compared with the EA group or the GAS group, the number of normal nerve cells in the striatum on the ischemic side of the EA+GAS group was further increased, and the positive expression level of RhoA and ROCK-2 were both further reduced.

CONCLUSION

The protective mechanism underlying the therapeutic efficacy of EA combined with Gas against cerebral ischemic striatal injury in rats may be associated with the inhibition of the activation of the RhoA/ROCK-2 signaling pathway. Importantly, the therapeutic effects observed with the combination of electroacupuncture and medication were superior to those achieved with EA alone or the sole administration of Gas.

Sympathetic-Mediated Intestinal Cell Death Contributes to Gut Barrier Impairment After Stroke

Tissue injury induced by stroke is traditionally thought to be localised to the brain. However, there is an accumulating body of evidence to demonstrate that stroke promotes pathophysiological consequences in peripheral tissues including the gastrointestinal system. In this study, we investigated the mechanisms underlying gut permeability after stroke. We utilised the clinically relevant experimental model of stroke called permanent intraluminal middle cerebral artery occlusion (pMCAO) to examine the effect of cerebral ischaemia on the gut. We detected stroke-induced gut permeability at 5 h after pMCAO. At this timepoint, we observed significantly elevated intestinal epithelial cell death in post-stroke mice compared to their sham-operated counterparts. At 24 h after stroke onset when the gut barrier integrity is restored, our findings indicated that post-stroke intestinal epithelium had higher expression of genes associated with fructose metabolism, and hyperplasia of intestinal crypts and goblet cells, conceivably as a host compensatory mechanism to adapt to the impaired gut barrier. Furthermore, we discovered that stroke-induced gut permeability was mediated by the activation of the sympathetic nervous system as pharmacological denervation decreased the stroke-induced intestinal epithelial cell death, goblet cell and crypt hyperplasia, and gut permeability to baseline levels. Our study identifies a previously unknown mechanism in the brain-gut axis by which stroke triggers intestinal cell death and gut permeability.

Polyphenol-rich Spondias mombin leaf extract abates cerebral ischemia/reperfusion-induced disturbed glutamate-ammonia metabolism and multiorgan toxicity in rats

Introduction: This study investigated the protective properties of Spondias mombin leaf extract (SML), in cerebral ischemia/reperfusion (I/R) mediated toxicity in the brain, liver, and kidney of male Wistar rats. Materials and methods: Animals were subjected to 30 min of bilateral common carotid artery occlusion followed by 24 h of reperfusion (BCCAO/R). The animals were divided into sham, I/R, and I/R treated with SML (25, 50 and 100 mg/kg) or quercetin (20 mg/kg) groups. Animals were sacrificed after 24 h of reperfusion and markers of organ toxicity (urea creatinine, glutamine synthetase (GS), glutaminase (GA), aspartate aminotransferase (AST), alanine aminotransferase (ALT), acetylcholinesterase (AChE)) were measured in the brain regions (cortex, striatum, and hippocampus), liver, and kidney. Results and discussion: BCCAO/R significantly (p < 0.0001) inhibited the glutamate-glutamine cycle and mediated toxicity in the cerebral cortex, striatum, hippocampus, liver, and kidney of rats. Post-treatment with SML significantly (p < 0.0001) reversed glutamate-glutamine cycle inhibition and ameliorated cerebrohepatorenal toxicity in ischemic rats. Conclusion: Cerebral I/R significantly mediated cerebral, hepatic, and renal toxicity through the inhibition of glutamate-ammonia detoxification in rats, and SML protected against this post-ischemic glutamate-ammonia mediated multiorgan toxicity.

Post-stroke administration of H2 relaxin reduces functional deficits, neuronal apoptosis and immune cell infiltration into the mouse brain

Brain inflammation and apoptosis contribute to neuronal damage and loss following ischaemic stroke, leading to cognitive and functional disability. It is well-documented that the human gene-2 (H2)-relaxin hormone exhibits pleiotropic properties via its cognate receptor, Relaxin Family Peptide Receptor 1 (RXFP1), including anti-inflammatory and anti-apoptotic effects, thus making it a potential therapeutic for stroke. Hence, the current study investigated whether post-stroke H2-relaxin administration could improve functional and histological outcomes. 8-12-week-old male C57BL/6 mice were subjected to sham operation or photothrombotic stroke and intravenously-administered with either saline (vehicle) or 0.02, 0.2 or 2 mg/kg doses of recombinant H2-relaxin at 6, 24 and 48 h post-stroke. Motor function was assessed using the hanging wire and cylinder test pre-surgery, and at 24 and 72 h post-stroke. Brains were removed after 72 h and infarct volume was assessed via thionin staining, and RXFP1 expression, leukocyte infiltration and apoptosis were determined by immunofluorescence. RXFP1 was identified on neurons, astrocytes and macrophages, and increased post-stroke. Whilst H2-relaxin did not alter infarct volume, it did cause a dose-dependent improvement in motor function at 24 and 72 h post-stroke. Moreover, 2 mg/kg H2-relaxin significantly decreased the number of apoptotic cells as well as macrophages and neutrophils within the ischaemic hemisphere, but did not alter T or B cells numbers. The anti-inflammatory and anti-apoptotic effects of H2-relaxin when administered at 6 h post-cerebral ischaemia may provide a novel therapeutic option for patients following ischaemic stroke.

The therapeutic role of Jingchuan tablet on ischaemic cerebral stroke via the HIF-1α/EPO/VEGFA signalling pathway

CONTEXT

Jingchuan tablet (JCT) is a Chinese medicine prescription for treating ischaemic cerebral stroke (ICS). However, its relevant mechanisms remain unclear.

OBJECTIVE

To unravel the intrinsic mechanisms of JCT anti-ICS.

MATERIALS AND METHODS

'Hongjingtian', 'chuanxiong', 'yanhusuo', 'bingpian', 'cerebral infarction', 'cerebral ischemia' or 'stroke' were used as keywords, and then components, targets and underlying mechanisms of JCT anti-ICS were analysed in TCMSP, TTD, DrugBank, STRING and Metascape databases up to June 2020. Male Sprague-Dawley rats under permanent middle cerebral artery occlusion (pMCAO) model, randomly assigned as: model, sham, nimodipine (0.012 g/kg/d) and JCT (0.78, 1.56 and 3.12 g/kg/d) groups, received oral gavage administration for a week. Therapeutic effects were evaluated by detecting the proportion of cerebral infarction, neuronal apoptosis and neurological deficits. Bioactive components were detected by HPLC-MS. Molecular biology and computational docking were used to verify the underlying mechanisms.

RESULTS

Eighty-one components, 166 targets and HIF-1α/EPO/VEGFA pathway contributed to the anti-ICS effect of JCT. JCT treatment effectively reduced the proportion of cerebral infarction (33.13%), apoptosis rate (14.80%) and neurobehavioural score (2.00). JCT increased the protein levels of HIF-1α (0.84), EPO (0.64) and VEGFA (0.69), respectively (p < 0.05). Gallic acid, salidroside, chlorogenic acid, ethyl gallate, ferulic acid and tetrahydropalmatine detected by HPLC-MS showed good interaction and binding with HIF-1α/EPO/VEGFA.

CONCLUSIONS

Our study demonstrated the mechanisms of JCT anti-ICS associated with the activation of the HIF-1α/EPO/VEGFA pathway, which provided a pharmacological basis for expanding the clinical application and some scientific ideas for further research into the material basis JCT anti-ICS.

Network pharmacology and in vitro experimental verification to explore the mechanism of Sanhua decoction in the treatment of ischaemic stroke

CONTEXT

Stroke is an illness with high morbidity, disability and mortality that presents a major clinical challenge. Sanhua decoction (SHD) has been widely used to treat ischaemic stroke in the clinic. However, the potential mechanism of SHD remains unknown.

OBJECTIVE

To elucidate the multitarget mechanism of SHD in ischaemic stroke through network pharmacology and bioinformatics analyses.

MATERIALS AND METHODS

Network pharmacology and experimental validation approach was used to investigate the bioactive ingredients, critical targets and potential mechanisms of SHD against ischaemic stroke. Four herbal names of SHD, 'ischemic stroke' or 'stroke' was used as a keyword to search the relevant databases. SH-SY5Y cells were treated with various concentrations of SHD (12.5, 25, 50 or 100 μg/mL) for 4 h, exposed to oxygen and glucose deprivation (OGD) for 1 h, then reoxygenation for 24 h. The cell viability was detected by MTT, the lactate dehydrogenase (LDH) was evaluated by ELISA, and protein expression was detected by western blots.

RESULTS

SHD treatment increased the survival rate from 65.9 ± 4.3 to 85.56 ± 5.7%. The median effective dose (ED₅₀) was 47.1 μg/mL, the LDH decreased from 288.0 ± 12.0 to 122.8 ± 9.1 U/L and the cell apoptosis rate decreased from 33.6 ± 1.8 to 16.3 ± 1.2%. Western blot analysis revealed that SHD increased the levels of p-PI3k, p-Akt and p-CREB1, and decreased the expression of TNF-α and IL-6.

DISCUSSION AND CONCLUSIONS

This study suggests that SHD protects against cerebral ischaemic injury via regulation of the PI3K/Akt/CREB1 and TNF pathways.

Adjuvant hyperbaric oxygen treatment of acute brain herniation after microsurgical clipping of a recurring cerebral aneurysm: a case report

INTRODUCTION

Acute brain herniation is a life-threatening neurological condition that occasionally develops due to severe complications following cerebral aneurysm clipping. Strategies for managing acute brain herniation have not improved substantially during the past decade. Hyperbaric oxygen treatment (HBOT) may alleviate harmful effects of cerebral hypoxia, which is one of the most important pathophysiological features of acute brain herniation and, therefore, may be useful as an adjuvant therapy for acute brain herniation. A case treated with adjuvant HBOT is reported.

CASE REPORT

A 60-year-old asymptomatic man presented with a recurring left middle cerebral artery bifurcation aneurysm with previous stent-assisted embolisation. After craniotomy for surgical clipping of the aneurysm, disturbance of consciousness and right hemiplegia occurred. Computed tomography (CT) images suggested simultaneous cerebral ischaemia and intracranial haemorrhage. Pharmacologic treatment resulted in no improvement. A CT scan acquired five days after surgery showed uncal and falcine herniation. HBOT was administered five days after surgery, and the patient's condition dramatically improved. He became conscious, and his hemiplegia improved following seven sessions of HBOT. Simultaneously, CT images showed regression of the acute brain herniation.

CONCLUSIONS

The patient had recovered completely at one year post-treatment. HBOT may be effective in the treatment of acute brain herniation following cerebral aneurysm clipping.

Seizures and epilepsy in patients with ischaemic stroke

BACKGROUND

With the increased efficacy of stroke treatments, diagnosis and specific treatment needs of patients with post-stroke seizures (PSS) and post-stroke epilepsy have become increasingly important. PSS can complicate the diagnosis of a stroke and the treatment of stroke patients, and can worsen post-stroke morbidity. This narrative review considers current treatment guidelines, the specifics of antiseizure treatment in stroke patients as well as the state-of-the-art in clinical and imaging research of post-stroke epilepsy. Treatment of PSS needs to consider indications for antiseizure medication treatment as well as individual clinical and social factors. Furthermore, potential interactions between stroke and antiseizure treatments must be carefully considered. The relationship between acute recanalizing stroke therapy (intravenous thrombolysis and mechanical thrombectomy) and the emergence of PSS is currently the subject of an intensive discussion. In the subacute and chronic post-stroke phases, important specific interactions between necessary antiseizure and stroke treatments (anticoagulation, cardiac medication) need to be considered. Among all forms of prevention, primary prevention is currently the most intensively researched. This includes specifically the repurposing of drugs that were not originally developed for antiseizure properties, such as statins. PSS are presently the subject of extensive basic clinical research. Of specific interest are the role of post-stroke excitotoxicity and blood-brain barrier disruption for the emergence of PSS in the acute symptomatic as well as late (> 1 week after the stroke) periods. Current magnetic resonance imaging research focussing on glutamate excitotoxicity as well as diffusion-based estimation of blood-brain barrier integrity aim to elucidate the pathophysiology of seizures after stroke and the principles of epileptogenesis in structural epilepsy in general. These approaches may also reveal new imaging-based biomarkers for prediction of PSS and post-stroke epilepsy.

CONCLUSION

PSS require the performance of individual risk assessments, accounting for the potential effectiveness and side effects of antiseizure therapy. The use of intravenous thrombolysis and mechanical thrombectomy is not associated with an increased risk of PSS. Advances in stroke imaging may reveal biomarkers for PSS.

Intracranial haemorrhage in late-onset neonatal group B streptococcal disease: A case report

This report aims to alert clinicians to the possibility of intracerebral haemorrhage as a rare manifestation of late-onset neonatal group B streptococcal (LOGBS) disease. This case also highlights the need for effective treatment guidelines for LOGBS disease. We report a case of LOGBS disease in a 17-day-old full-term female neonate, complicated by bilateral subarachnoid haemorrhage confirmed on magnetic resonance imaging (MRI). The patient presented with fever, lethargy, and convulsions. Microbiological examination confirmed the presence of Streptococcus agalactiae in the blood culture. Brain MRI showed bilateral subarachnoid haemorrhage and diffuse cerebral ischaemia, suggesting a severe complication of LOGBS disease. Short-term follow-up of the patient showed marked developmental delay. Early screening for group B streptococcus infection in pregnant women is essential to prevent severe cases of LOGBS disease. Very few cases of intracerebral haemorrhage in LOGBS disease have been reported. Further evidence is required to support a pertinent link between LOGBS disease and intracerebral haemorrhage.

Moyamoya disease in Mexico: our experience

INTRODUCTION

Moyamoya disease (MD) is a progressive, occlusive disease of the arteries of the anterior cerebral circulation that may cause ischaemia or haemorrhage. Patient management aims to prevent new cerebrovascular events through surgical revascularisation and/or pharmacological treatment.

MATERIALS AND METHODS

We studied a series of 17 patients with MD (n = 14) or moyamoya syndrome (MS; n = 3), who were evaluated between January 1989 and December 2016; 11 patients were women and 6 were men. Thirteen patients had definitive MD (76%), one had unilateral MD (5.2%), and 3 had MS (18%). The condition manifested as intraparenchymal haemorrhage (in 35.2% of patients), brain ischaemia (29.4%), subarachnoid haemorrhage (17.6%), seizures (11.7%), and headache with no associated haemorrhage (1 patient).

RESULTS

Ten patients (58.8%) underwent revascularisation and 7 (41.2%) received pharmacological treatment. All patients were evaluated with the modified Rankin Scale (mRs) at admission and at the last consultation; mRs scores were significantly lower in the group undergoing surgery (P <  .04). During follow-up, none of the patients undergoing revascularisation experienced recurrences, whereas 2 patients receiving pharmacological treatment did experience a new vascular event (one ischaemic and one haemorrhagic) (P <  .05). No significant differences were observed between the treatment outcomes of different revascularisation techniques.

CONCLUSIONS

Although our population has different demographic characteristics from those of other non-Asian populations, ours is the largest published series of Hispanic individuals with MD. Our results support the use of revascularisation procedures to improve these patients' neurological status and to prevent new cerebrovascular events.

Overview and Diagnostic Accuracy of Near Infrared Spectroscopy in Carotid Endarterectomy: A Systematic Review and Meta-analysis

OBJECTIVE

Carotid endarterectomy is recommended for the prevention of ischaemic stroke due to carotid stenosis. However, the risk of stroke after carotid endarterectomy has been estimated at 2% - 5%. Monitoring intra-operative cerebral oxygenation with near infrared spectroscopy (NIRS) has been assessed as a strategy to reduce intra- and post-operative complications. The aim was to summarise the diagnostic accuracy of NIRS to detect intra-operative ischaemic events, the values associated with ischaemic events, and the relative contribution of external carotid contamination to the NIRS signal in adults undergoing carotid endarterectomy.

DATA SOURCES

EMBASE, MEDLINE, Cochrane Centre Register of Controlled Trials, and reference lists through May 2019 were searched.

REVIEW METHODS

Non-randomised and randomised studies assessing NIRS as an intra-operative monitoring tool in carotid endarterectomy were included. Studies using NIRS as the reference were excluded. Risk of bias was assessed using the Newcastle Ottawa Scale, RoB-2, and QUADAS-2.

RESULTS

Seventy-six studies were included (n = 8 480), under local (n = 1 864) or general (n = 6 582) anaesthesia. Seven studies were eligible for meta-analysis (n = 524). As a tool for identifying intra-operative ischaemia, specificity increased with more stringent NIRS thresholds, while there was unpredictable variation in sensitivity across studies. A Δ20% threshold under local anaesthesia resulted in pooled estimates for sensitivity and specificity of 70.5% (95% confidence interval, CI, 54.1 - 82.9) and 92.4% (95% CI 85.5 - 96.1) compared with awake neurological monitoring. These studies had low or unclear risk of bias. NIRS signal consistently dropped across clamping and recovered to pre-clamp values upon de-clamp in most studies, and larger decreases were observed in patients with ischaemic events. The contribution of extracranial signal to change in signal across clamp varied from 3% to 50%.

CONCLUSION

NIRS has low sensitivity and high specificity to identify intra-operative ischaemia compared with awake monitoring. Extracranial signal contribution was highly variable. Ultimately, data from high quality studies are desperately needed to determine the utility of NIRS.

The emerging possibility of the use of geniposide in the treatment of cerebral diseases: a review

With the advanced discoveries in the field of pathogenesis, a series of cerebral diseases, such as cerebral ischaemia, Alzheimer's disease, and depression, have been found to have multiple signalling targets in the microenvironment. Only a few existing agents have been shown to have curative effects due to this specific circumstance. In recent decades, active ingredients isolated from natural plants have been shown to be crucial for original drug development. Geniposide, mainly extracted from Gardenia jasminoides Ellis, is representative of these natural products. Geniposide demonstrates various biological activities in the treatment of cerebral, cardiovascular, hepatic, tumorous, and other diseases. The multiple protective effects of geniposide on the brain have especially drawn increasing attention. Thus, this article specifically reviews the characteristics of current models of cerebral ischaemia and illustrates the possible effects of geniposide and its pathogenetic mechanisms on these models. Geniposide has been shown to significantly reduce the area of cerebral infarction and alleviate neuronal damage and necrosis mainly by inhibiting inflammatory signals, including NLRP3, TNF-α, IL-6, and IL-1β. Neuronal protection was also involved in activating the PI3K/Akt and Wnt/catenin pathways. Geniposide was able to increase autophagy and inhibit apoptosis by regulating the function of mTOR in treating Alzheimer's disease. Geniposide has also been shown to act as a glucagon-like peptide-1 receptor (GLP-1R) agonist to reduce amyloid plaques and inhibit oxidative stress to alleviate memory impairment as well as synaptic loss. Moreover, geniposide has been shown to exert antidepressant effects primarily by regulating the hypothalamic-pituitary-adrenal (HPA) axis. Detailed explorations have shown that the biological activities of inhibiting inflammatory cytokine secretion, alleviating oxidative stress, and suppressing mitochondrial damage are also involved in the mechanism of action of geniposide. Therefore, geniposide is a promising agent awaiting further exploration for the treatment of cerebral diseases via various phenotypes or signalling pathways.

A randomized evaluation of the TriGuard™ HDH cerebral embolic protection device to Reduce the Impact of Cerebral Embolic LEsions after TransCatheter Aortic Valve ImplanTation: the REFLECT I trial

AIMS

The REFLECT I trial investigated the safety and effectiveness of the TriGuard™ HDH (TG) cerebral embolic deflection device in patients undergoing transcatheter aortic valve replacement (TAVR).

METHODS AND RESULTS

This prospective, multicentre, single-blind, 2:1 randomized (TG vs. no TG) study aimed to enrol up to 375 patients, including up to 90 roll-in patients. The primary combined safety endpoint (VARC-2 defined early safety) at 30 days was compared with a performance goal. The primary efficacy endpoint was a hierarchical composite of (i) all-cause mortality or any stroke at 30 days, (ii) National Institutes of Health Stroke Scale (NIHSS) worsening at 2-5 days or Montreal Cognitive Assessment worsening at 30 days, and (iii) total volume of cerebral ischaemic lesions detected by diffusion-weighted magnetic resonance imaging at 2-5 days. Cumulative scores were compared between treatment groups using the Finkelstein-Schoenfeld method. A total of 258 of the planned, 375 patients (68.8%) were enrolled (54 roll-in and 204 randomized). The primary safety outcome was met compared with the performance goal (21.8% vs. 35%, P < 0.0001). The primary hierarchical efficacy endpoint was not met (mean efficacy score, higher is better: -5.3 ± 99.8 TG vs. 11.8 ± 96.4 control, P = 0.31). Covert central nervous system injury was numerically lower with TG both in-hospital (46.1% vs. 60.3%, P = 0.0698) and at 5 days (61.7 vs. 76.2%, P = 0.054) compared with controls.

CONCLUSION

REFLECT I demonstrated that TG cerebral protection during TAVR was safe in comparison with historical TAVR data but did not meet the predefined effectiveness endpoint compared with unprotected TAVR controls.

Salvianolate lyophilized injection regulates the autophagy-lysosomal pathway in cerebral ischaemia/reperfusion rats

ETHNOPHARMACOLOGICAL RELEVANCE

Activation of autophagy has been implicated in cerebral ischiemia/reperfusion (I/R) injury. Salvianolate lyophilized injection (SLI) has been widely used in the clinical treatment of cerebrovascular disease in China. Whether SLI has any influence on the activation of autophagy in cerebral I/R injury remains elusive.

AIM OF THE STUDY

The aim of this study were to assess whether SLI attenuates I/R-induced brain injury and evaluate its associated mechanisms.

MATERIALS AND METHODS

Focal cerebral ischaemia was induced by middle cerebral artery occlusion (MCAO). SLI (21 mg/kg) was injected intravenously at the beginning of the reperfusion period and 24 and 48 h after ischaemia. The effects of SLI on brain injury were detected according to infarct volume, neurological score, brain oedema, and HE and TUNEL staining at 72 h post-MCAO. Western blotting was used to detect alterations in the autophagy-relevant proteins LC3, Beclin-1, mTOR, p62, Lamp-1, and CTSD in the ipsilateral cortex at 24 or 72 h post-MCAO.

RESULTS

We first demonstrated that SLI significantly alleviated the infarct volume, neurological deficits, and brain oedema, and reduced the number of TUNEL-positive cells in rats with cerebral I/R injury. Next, we found that SLI has a bidirectional regulatory effect on autophagy: early-stage (24 h) cerebral ischaemia promotes the activation of autophagy and developmental-stage (72 h) cerebral ischaemia has an inhibitory effect. SLI enhanced I/R-induced autophagy as evidenced by the increased expression level of the autophagy marker protein LC3Ⅱ, as well as the decreased expression of mTOR and the autophagy substrate protein p62, but there was no change in lysosomal activity at 24 h after I/R-induced injury. Moreover, SLI also inhibited excessive activation of autophagy at 72 h after I/R-induced injury, which manifested as downregulating LC3Ⅱ expression, upregulating mTOR and p62 expression, and inhibiting lysosomal activity.

CONCLUSION

SLI has a protective effect on cerebral ischaemia/reperfusion injury, which may be mediated by the autophagy-lysosome pathway.

Mechanical thrombectomy beyond 6hours in acute ischaemic stroke with large vessel occlusion in the carotid artery territory: Experience at a tertiary hospital

INTRODUCTION

Thrombectomy in the carotid artery territory was recently shown to be effective up to 24hours after symptoms onset.

METHODS

We conducted a retrospective review of a prospective registry of patients treated at our stroke reference centre between November 2016 and April 2019 in order to assess the safety and effectiveness of mechanical thrombectomy performed beyond 6hours after symptoms onset in patients with acute ischaemic stroke and large vessel occlusion in the carotid artery territory.

RESULTS

Data were gathered from 59 patients (55.9% women; median age, 71 years). In 33 cases, stroke was detected upon awakening; 57.6% of patients were transferred from another hospital. Median baseline NIHSS score was 16, and median ASPECTS score was 8, with 94.9% of patients presenting>50% of salvageable tissue. Satisfactory recanalisation was achieved in 88.1% of patients, beyond 24hours after onset in 5 cases. At 90 days of follow-up, 67.8% were functionally independent; those who were not were older and presented higher prevalence of atrial fibrillation, greater puncture-to-recanalisation time, and higher NIHSS scores, both at baseline and at discharge.

CONCLUSION

In our experience, mechanical thrombectomy beyond 6hours was associated with good 90-day functional outcomes. Age, NIHSS score, puncture-to-recanalisation time, and presence of atrial fibrillation affected functional prognosis. The efficacy of the treatment beyond 24hours after onset merits study.

Treadmill exercise attenuates cerebral ischaemic injury in rats by protecting mitochondrial function via enhancement of caveolin-1

AIMS

Exercise training has a neuroprotective effect against ischaemic injury, but the underlying mechanism is not completely clear. This study explored the potential mechanisms underlying the protective effects of treadmill training and caveolin-1 regulation against mitochondrial dysfunction in cerebral ischaemic injury.

MAIN METHODS

After middle cerebral artery occlusion (MCAO) surgery, rats were subjected to treadmill training and received daidzein injections and combined therapy. A series of analyses, including neurological function scoring; body weight measurement; Nissl, haematoxylin and eosin staining; cerebral infarction volume assessment; mitochondrial morphology examination; caveolin-1, cytoplasmic and mitochondrial cytochrome C (CytC), and translocase of outer membrane 20 (TOM20) expression analysis; apoptosis index analysis; and transmission electron microscopy were conducted.

KEY FINDINGS

Treadmill training increased caveolin-1 expression, reduced neurobehavioral scores and cerebral infarction volumes, improved tissue morphology, reduced neuronal loss, inhibited mitochondrial outer membrane permeabilization (MOMP) through the caveolin-1 pathway, prevented excessive Cyt-C release from mitochondria, and reduced the degrees of apoptosis and mitochondrial damage. In addition, treadmill training increased the expression of TOM20 through the caveolin-1 pathway and maintained import signal function, thereby protecting mitochondrial integrity.

SIGNIFICANCE

Treadmill exercise protected mitochondrial integrity and inhibited the endogenous mitochondrial apoptosis pathway. The damage of cerebral ischaemia was alleviated in rats through enhancement of caveolin-1 by treadmill exercise.

Early epileptic seizures in ischaemic stroke treated by mechanical thrombectomy: influence of rt-PA

BACKGROUND

The epileptogenicity of recombinant tissue-plasminogen activator (rt-PA) has been suggested, but seizures were not evaluated in randomised controlled trials.

OBJECTIVE

To evaluate whether rt-PA was associated with early seizures in a cohort of consecutive patients with cerebral ischaemia.

METHOD

We included consecutive adults with ischaemic stroke due to large-vessel occlusion from the North-of-France stroke network selected for a mechanical thrombectomy (MT). Patients without contraindication received i.v. rt-PA. We evaluated stroke severity with the National Institutes of Health Stroke Scale (NIHSS), and functional status with the modified Rankin scale (mRS), and recorded epileptic seizures occurring between the end of imaging and day 7. We performed statistics using propensity analyses.

RESULTS

We included 1638 patients (783 men, 47.8%; median age 71 years; median NIHSS score 16; 1007 treated by rt-PA, 61.5%), in whom 60 (3.7%) developed early epileptic seizures. After adjustment on propensity scores, early seizures were associated with infections [adjusted odds ratio (_adjOR) 2.86; 95% confidence interval (CI) 1.37-5.95] and delay between stroke recognition and end of MT (_adjOR 1.04 for 10 min more; 95% CI 1.01-1.08), but not with rt-PA (_adjOR 1.35; 95% CI 0.55-3.33). The propensity-matched analysis of 343 pairs of patients found no difference in the occurrence of early seizures between those with and without rt-PA (p = 0.386).

CONCLUSION

We found no significant association between rt-PA and early epileptic seizures. If rt-PA has the potential for epileptogenicity, the magnitude of the effect should be modest compared to its favourable effect on functional outcome.

Cerebral ischaemia with unknown onset: Outcome after recanalization procedure

BACKGROUND

Stroke of unknown time of onset (UTOS) accounts for one-third of contra-indications for revascularization procedures. With modern neuroimaging techniques it is possible to differentiate the core infarcts and the presence of penumbra.

OBJECTIVE

To evaluate outcomes in patients with UTOS, treated with intravenous (i.v.) recombinant tissue-plasminogen activator (rt-PA), mechanical thrombectomy (MT), or both.

METHOD

We conducted this observational study in patients treated by i.v. rt-PA, MT, or both, selected by a diffusion-weighted image/fluid-attenuated inversion recovery mismatch. We evaluated outcomes with the modified Rankin scale (mRS) at 3 months.

RESULTS

Of 992 consecutive patients (522 women, 52.6%; median age 76 years; median baseline national institutes of health stroke scale [NIHSS] 10), 153 (15.4%) had UTOS, including 101 with wake-up strokes. Compared to other patients, they were more likely to have pre-existing mRS scores >2 (P=0.022), multiple infarcts (P<0.001), middle cerebral artery occlusions (P=0.023), and to undergo MT (P=0.003), and less likely to receive i.v. rt-PA (P<0.001). They had higher NIHSS scores (P<0.001) and longer discovery to treatment initiation times (P<0.001). They were more likely to develop pulmonary (P=0.001) and urinary (P=0.006) infections, and pulmonary embolism (P=0.019), and tended to have a higher mortality rate (P=0.052) within 7 days. After adjustment, there was no association of UTOS with any of these outcome measures anymore.

CONCLUSION

Patients with UTOS have more severe strokes and more comorbidities, but after adjustment, their outcomes did not differ from those of other patients.

Access to mechanical thrombectomy for cerebral ischaemia: A population-based study in the North-of-France

BACKGROUND AND PURPOSE

Hospitals admitting acute strokes should offer access to mechanical thrombectomy (MT), but local organisations are still based on facilities available before MT was proven effective. MT rates and outcomes at population levels are needed to adapt organisations. We evaluated rates of MT and outcomes in inhabitants from the North-of-France (NoF) area.

METHOD

We prospectively evaluated rates of MT and outcomes of patients at 3 months, good outcomes being defined as a modified Rankin scale (mRS) 0 to 2 or like the pre-stroke mRS.

RESULTS

During the study period (2016-2017), 666 patients underwent MT (454, 68.1% associated with intravenous thrombolysis [IVT]). Besides, 1595 other patients received IVT alone. The rate of MT was 81 (95% confidence interval [CI] 72-90) per million inhabitants-year, ranging from 36 to 108 between districts. The rate of IVT was 249 (95% CI 234-264) per million inhabitants-year, ranging from 155 to 268. After 3 months, 279 (41.9%) patients who underwent MT had good outcomes, and 167 (25.1%) had died. Patients living outside the district of Lille where the only MT centre is, were less likely to have good outcomes at 3 months, after adjustment on age, sex, baseline severity, and delay.

CONCLUSION

The rate of MT is one of the highest reported up to now, even in low-rate districts, but outcomes were significantly worse in patients living outside the district of Lille, and this is not only explained by the delay.

The relationship between ischaemic brain lesions and cognitive outcome after aneurysmal subarachnoid haemorrhage

Background

Cerebral ischaemia is thought to be an important determinant of cognitive outcome after aneurysmal subarachnoid haemorrhage (aSAH), but the exact relationship is unclear. We studied the effect of ischaemic brain lesions during clinical course on cognitive outcome 2 months after aSAH.

Methods

We studied 74 consecutive patients admitted to the University Medical Center Utrecht who had MRI post-coiling (3–21 days post-aSAH) and neuropsychological examination at 2 months. An ischaemic lesion was defined as hyperintensity on T2-FLAIR and DWI images. We measured both cognitive complaints (subjective) and cognitive functioning (objective). The relationship between ischaemic brain lesions and cognitive outcome was analysed by logistic regression analyses.

Results

In 40 of 74 patients (54%), 152 ischaemic lesions were found. The median number of lesions per patient was 2 (1–37) and the median total lesion volume was 0.2 (0–17.4) mL. No difference was found between the group with and the group without ischaemic lesions with respect to the frequency of cognitive complaints. In the group with ischaemic lesions, significantly more patients (55%) showed poor cognitive functioning compared to the group without ischaemic lesions (26%) (OR 3.4, 95% CI 1.3–9.1). We found no relationship between the number and volume of the ischaemic lesions and cognitive functioning.

Conclusions

Ischaemic brain lesions detected on MRI during clinical course after aSAH is a marker for poor cognitive functioning 2 months after aSAH, irrespective of the number or volume of the ischaemic lesions. Network or connectivity studies are needed to better understand the relationship between location of the ischaemic brain lesions and cognitive functioning.

Circulating Microparticles in Patients with Symptomatic Carotid Disease Are Related to Embolic Plaque Activity and Recent Cerebral Ischaemia

Background and Purpose

In order to assess the association of microparticles derived from activated platelets (PMP) or endothelial cells (EMP) with risk markers for recurrent embolic events in patients with symptomatic carotid artery disease, we studied the associations between PMP/EMP and three risk markers: plaque haemorrhage (PH), micro-embolic signals and cerebral diffusion abnormalities.

Methods

Patients with recently symptomatic high-grade carotid artery stenosis (60–99%, 42 patients, 31 men; mean age 75 ± 8 years) and 30 healthy volunteers (HV, 11 men; mean age 56 ± 12 years) were prospectively recruited. Patients were characterised by carotid magnetic resonance imaging (presence of PH [MRI PH]), brain diffusion MRI (cerebral ischaemia [DWI+]) and transcranial Doppler ultrasound (micro-embolic signals [MES+]). PMP and EMP were classified by flow cytometry and expressed as log-transformed counts per microlitre.

Results

MES+ patients (n = 18) had elevated PMP (MES+ 9.61 ± 0.57) compared to HV (8.80 ± 0.73; p < 0.0001) and to MES– patients (8.55 ± 0.85; p < 0.0001). Stroke patients had elevated PMP (9.49 ± 0.64) and EMP (6.13 ± 1.0) compared to non-stroke patients (PMP 8.81 ± 0.73, p = 0.026, EMP 5.52 ± 0.65, p = 0.011) and HV (PMP 8.80 ± 0.73, p = 0.007, and EMP 5.44 ± 0.47, p = 0.006). DWI+ patients (n = 16) showed elevated PMP (DWI+ 9.53 ± 0.64; vs. HV, p = 0.002) and EMP (DWI+ 5.91 ± 0.99 vs. HV 5.44 ± 0.47; p = 0.037). Only PMP but not EMP were higher in DWI+ versus DWI– patients (8.67 ± 0.90; p = 0.002). No association was found between PMP and EMP with MRI PH.

Conclusion

PMP and EMP were associated with stroke and recent cerebrovascular events (DWI+) but only PMP were also associated with ongoing (MES+) thrombo-embolic activity suggesting a differential biomarker potential for EMP to index cerebral ischaemia while PMP may predict on-going thrombo-embolic activity.

General anesthesia considerations in CADASIL disease

CADASIL (cerebral arteriopathy, autosomal dominant, with subcortical infarcts and leukoencephalopathy) disease is an inherited systemic arterial disease that affects the small and medium calibre cerebral vessels. Around 500 families are affected in the world, most of them in Europe. It is characterised by migraine attacks, subcortical dementia, neuropsychiatric disorders, and recurrent ischaemic strokes. The objective of this article is to describe, for the first time in the literature, the management by general anaesthesia of an intracranial neurosurgical procedure in a patient with CADASIL disease. Continuous monitoring of blood pressure is considered essential, as well as the maintenance of normocapnia and normothermia to avoid the development of new cerebrovascular accidents. This disease is relevant due to its anaesthetic implications and the few publications to date.

Simultaneous Multi-Supra-Aortic Artery Bypass Successfully Implemented in 17 Patients with Type I Takayasu Arteritis

OBJECTIVE

Type I Takayasu arteritis is common in Chinese patients and usually leads to cerebral ischaemia. There are limited data regarding simultaneous multi-supra-aortic artery (SMSAA) bypass in patients with type I Takayasu arteritis. The present study shares experience of using this method.

METHODS

Seventeen patients with Takayasu arteritis who received SMSAA bypass from June 2012 to March 2016 were included in this analysis. Demographic features and basic information were recorded. Follow up results, including major complications, patency rates, and survival rates, were also obtained. The EQ-5D questionnaire was also administered to evaluate the quality of life of patients.

RESULTS

Among these 17 patients, there were 77 supra-aortic arteries affected by TA and 37 arteries were reconstructed, 10 with great saphenous vein and 27 with artificial blood vessels. All the operations were technical successes and the mean operation time was 396.6 ± 93.4 min. The patients were followed for a mean of 25.2 ± 12.3 months. Two graft restenoses were found, and both were successfully recanalised by balloon dilatation. One patient suffered a minor stroke but was free from obvious sequelae. No major complications, recurrent symptoms, or deaths occurred during the follow up period. The EQ-5D questionnaire scores were significantly improved after the operation compared with the pre-operative scores (87.14 ± 8.25 vs. 58.93 ± 14.4, p < .01), and all the patients enjoyed a satisfactory quality of life.

CONCLUSION

SMSAA bypass in type I Takayasu arteritis can be effectively and safely performed with rigorous peri-operative management. Maintaining the patency of the bypass graft relieves the symptoms of cerebral ischaemia and helps sustain patients' quality of life.

Moyamoya disease in Mexico: Our experience

INTRODUCTION

Moyamoya disease (MD) is a progressive, occlusive disease of the arteries of the anterior cerebral circulation that may cause ischaemia or haemorrhage. Patient management aims to prevent new cerebrovascular events through surgical revascularisation and/or pharmacological treatment.

METHODS

We studied a series of 17 patients with MD (n = 14) or moyamoya syndrome (n = 3), who were evaluated between January 1989 and December 2016; 11 patients were women and 6 were men. Thirteen patients had definitive MD (76%), one had unilateral MD (5.2%), and 3 had moyamoya syndrome (18%). The condition manifested as intraparenchymal haemorrhage (in 35.2% of patients), brain ischaemia (29.4%), subarachnoid haemorrhage (17.6%), seizures (11.7%), and headache with no associated haemorrhage (one patient).

RESULTS

Ten patients (58.8%) underwent revascularisation and 7 (41.2%) received pharmacological treatment. All patients were evaluated with the modified Rankin Scale (mRs) at admission and at the last consultation; mRs scores were significantly lower in the group undergoing surgery (P < .04). During follow-up, none of the patients undergoing revascularisation experienced recurrences, whereas 2 patients receiving pharmacological treatment did experience a new vascular event (one ischaemic and one haemorrhagic) (P < .05). No significant differences were observed between the treatment outcomes of different revascularisation techniques.

CONCLUSIONS

Although our population has different demographic characteristics from those of other non-Asian populations, ours is the largest published series of Hispanic individuals with MD. Our results support the use of revascularisation procedures to improve these patients' neurological status and to prevent new cerebrovascular events.

The protective roles of L-borneolum, D-borneolum and synthetic borneol in cerebral ischaemia via modulation of the neurovascular unit

OBJECTIVE

Borneol has been used to treat stroke in China since ancient times. In our previous research, we demonstrated the effect of borneol on cerebral ischaemia injury via meta-analysis. The neurovascular unit (NVU) is the structural basis of the preservation of the brain microenvironment and is believed to be a promising target in treating stroke. In this research, we explored the roles of three kinds of borneol, namely, L-borneolum (B1), D-borneolum (B2) and synthetic borneol (B3), in the NVU with permanent middle cerebral artery occluded (pMCAO) rats.

METHODS

The Longa scoring method was used to evaluate nerve function deficits in the pMCAO rats. Awakening time, brain water content, brain index and brain edema rate were also measured. TTC staining was used to calculate the cerebral infarction rate. The morphology of the ischaemia penumbra brain tissue was observed via HE staining, and the neuronal denatured cell index (DCI) was calculated. An enzyme-linked immunosorbent assay (ELISA) was used to determine the levels of vascular endothelial growth factor VEGF and TNF-α in the serum. Moreover, the ultrastructures of the neurons and of the blood-brain barrier (BBB) were observed using transmission electron microscopy. The expression levels of Claudin-5, Bcl-2 and Bax in the ischaemia penumbra of pMCAO rats were detected using real-time PCR and immunohistochemistry.

RESULTS

Pretreatment with B1, B2 and B3 delayed the recovery time (P < 0.01). B1 remarkably ameliorated neurological deficits 24 h after cerebral ischaemia (P < 0.05). Moreover, B1 and B3 were both able to ameliorate brain edema and the area of cerebral infarction. In addition, B1, B2 and B3 all increased serum VEGF levels and decreased serum TNF-α levels (P < 0.01). For the ultrastructure determination, the BBB and the nerve centre were significantly improved by B1, B2 and B3. The mechanistic exploration revealed that B2 and B3 protected the brain by reducing the Bax/Bcl-2 ratio (P < 0.05, P < 0.01, respectively). Immunohistochemistry suggested that B1, B2 and B3 could also enhance the expression of Claudin-5 (P < 0.01).

CONCLUSION

The three kinds of borneol demonstrated different protective effects on cerebral ischaemia injury. L-Borneolum displayed the most prominent anti-cerebral ischaemia effect among them. The mechanism was most likely executed via anti-apoptosis and anti-inflammation effects and maintenance of the stability of the BBB and TJs to comprehensively improve NVU function.

Inclusion criteria update for the rat intraluminal ischaemic model for preclinical studies

Proper occlusion of the medial cerebral artery, as determined by laser Doppler monitoring, during cerebral ischaemia in rat models is an important inclusion criterion in experimental studies. However, successful occlusion of the artery does not always guarantee a reproducible infarct volume, which is crucial for validating the efficacy of new protective drugs. In a rat intraluminal ischaemic model, laser Doppler monitoring alone was compared with laser Doppler monitoring in combination with magnetic resonance angiography (MRA) and diffusion-weighted imaging (DWI). Twenty-eight animals showed successful occlusion and reperfusion determined with Doppler monitoring, with an infarct size at 24 h of 16.7±11.5% (determined as ischaemic damage with respect to the ipsilateral hemisphere volume). However, when arterial occlusion and infarct damage were analysed in these animals using MRA and DWI, respectively, 15 animals were excluded and only 13 animals were included, with an infarct size at 24 h of 21.6±6.1%, showing a variability in the infarct size significantly lower (P<0.05, F-test) than that obtained with Doppler monitoring alone. We also observed that blocking of the pterygopalatine artery (a maxillary artery that is usually occluded in the intraluminal ischaemic model) was not relevant for this model, at least in terms of infarct variability. These results show that laser Doppler monitoring is a necessary procedure, but not sufficient to guarantee a reproducible infarct volume, in a rat ischaemic model. Therefore, laser Doppler monitoring in combination with DWI and MRA represents a reliable inclusion protocol during ischaemic surgery for the analysis of new protective drugs.

Summary: Laser Doppler monitoring in combination with diffusion-weighted imaging and magnetic resonance angiography represents a reliable inclusion protocol during ischaemic surgery for the analysis of protective drugs in the acute phase of stroke.

Improvement of 2-Vessel Occlusion Cerebral Ischaemia/Reperfusion-Induced Corticostriatal Electrolyte and Redox Imbalance, Lactic Acidosis and Modified Acetylcholinesterase Activity by Kolaviron Correlates with Reduction in Neurobehavioural Deficits

Background

Disruption of electrolyte, redox and neurochemical homeostasis alongside cellular energy crisis is a hallmark of cerebral ischaemia and reperfusion injury.

Purpose

This study investigated the effect of kolaviron (KV) on cortical and striatal cation imbalance, oxidative stress and neurochemical disturbances as well as neurobehavioural deficits in animals subjected to bilateral common carotid artery occlusion (BCCAO)-induced ischaemia/reperfusion injury.

Methods

KV was administered at a dose of 100 or 200 mg/kg to male Wistar rats 1 h before a 30 min BCCAO/4 h reperfusion (I/R). This was followed by neurobehavioral assessment and biochemical evaluations of cation levels, oxidative stress indicators, lactate dehydrogenase activity and acetylcholinesterase (AChE) activity in the brain of animals.

Conclusion

KV significantly restored altered cortical and striatal Ca²⁺, Na⁺, K⁺ and Mg²⁺ levels, ameliorated redox imbalance, lactic acidosis and modified AChE activity caused by I/R injury. The favourable neurobehavioural effects of KV correlated with biochemical outcomes. The pharmacological potential of KV in the treatment and management of ischemic stroke and allied pathological conditions via multiple targets (neurotransmitter metabolism, bioenergetic failure and ionic homeostasis) is highlighted by the study.

Cerebral ischaemia following anterior upper thoracic spinal surgery utilizing a partial manubrial resection

PURPOSE

Firstly, to describe two cases of cerebral ischaemia complicating anterior upper thoracic spinal surgery and define the likely cause of this complication. Secondly, to describe preventative measures and the effect these have had in reducing this complication within our institution.

METHODS

Firstly, a review of two cases of cerebral ischaemia complicating anterior upper thoracic spinal surgery utilizing a partial manubrial resection. Secondly, cadaveric dissections of the carotid arteries to determine the effect of neck positioning and aortic arch retraction during a simulated procedure. Thirdly, a retrospective review of 65 consecutive cases undergoing this procedure and assessment of the rate of this complication before and after the adoption of preventative measures.

RESULTS

Two cases of carotid artery territory cerebral ischaemia, without radiographic evidence of carotid or cardiac pathology were identified in 50 consecutive cases prior to the implementation of preventative measures. These patients revealed fluctuating hemodynamic instability after placement of the inferior retractor. Cadaveric dissection reveals significant carotid artery traction particularly with neck extension. Since the adoption of preventative measures, no cases of cerebral ischaemia have been encountered.

CONCLUSIONS

Cerebral ischaemia is a potential complication of anterior upper thoracic spinal surgery requiring retraction of the aortic arch. This most likely occurs from carotid stenosis due to aortic retraction and therefore, may be reduced by positioning the patient with neck flexion. Continuous non-invasive monitoring of cerebral saturation, as well as actively monitoring for hemodynamic instability and reduced carotid pulsation after retractor placement, allows for early detection of this complication. If detected, perfusion can be easily restored by reducing the retraction of aortic arch.

Mechanical reperfusion with leucocyte-filtered blood does not prevent injury following global cerebral ischaemia

Objectives

Prolonged global cerebral ischaemia leads to irreversible injury, often with lethal outcome. Brain injuries are partly caused by the uncontrolled reperfusion that occurs once the circulation is re-established. Recent animal experiments suggest that controlled reperfusion following lengthy ischaemia might prevent severe brain injury. This study aimed at further exploring cerebral alterations and outcome following prolonged global cerebral ischaemia and mechanically manipulated reperfusion.

Methods

Three groups of pigs were included; one sham operated ( n  = 3) and two that underwent 30-min global cerebral ischaemia. All vessels that supply the brain were isolated intrathoracically, after which they were occluded for 30 min in the ischaemic groups. In one of the ischaemic groups uncontrolled reperfusion was applied (URep, n  = 6), i.e. normal circulation was restored 30 min after arrested cerebral circulation. The second ischaemic group received mechanical reperfusion (MRep, n  = 6) with leucocyte-filtered blood at constant flow and pressure for 20 min using extracorporeal circulation following the 30-min ischaemia, after which normal blood flow resumed. All animals were monitored for 3 h after start of uncontrolled reperfusion. Haemodynamic parameters, arterial and sagittal sinus blood gases, cerebral oxygen extraction rates and intraparenchymal biomarkers using microdialysis were measured. Brain histology was performed post-mortem.

Results

Global brain ischaemia led to the same extent of severe morphological changes at the level of light microscopy in the two ischaemic experimental groups, regardless of reperfusion protocol. Furthermore, no significant differences were found between the URep and MRep groups regarding cerebral blood gases or microdialysis biomarkers.

Conclusions

Mechanical reperfusion following the current protocol does not modify brain alterations caused by 30 min of arrested cerebral circulation.

Non-invasive near-infrared fluorescence imaging of the neutrophil response in a mouse model of transient cerebral ischaemia

Near-infrared fluorescence (NIRF) imaging enables non-invasive monitoring of molecular and cellular processes in live animals. Here we demonstrate the suitability of NIRF imaging to investigate the neutrophil response in the brain after transient middle cerebral artery occlusion (tMCAO). We established procedures for ex vivo fluorescent labelling of neutrophils without affecting their activation status. Adoptive transfer of labelled neutrophils in C57BL/6 mice before surgery resulted in higher fluorescence intensities over the ischaemic hemisphere in tMCAO mice with NIRF imaging when compared with controls, corroborated by ex vivo detection of labelled neutrophils using fluorescence microscopy. NIRF imaging showed that neutrophils started to accumulate immediately after tMCAO, peaking at 18 h, and were still visible until 48 h after reperfusion. Our data revealed accumulation of neutrophils also in extracranial tissue, indicating damage in the external carotid artery territory in the tMCAO model. Antibody-mediated inhibition of α4-integrins did reduce fluorescence signals at 18 and 24, but not at 48 h after reperfusion, compared with control treatment animals. Antibody treatment reduced cerebral lesion volumes by 19%. In conclusion, the non-invasive nature of NIRF imaging allows studying the dynamics of neutrophil recruitment and its modulation by targeted interventions in the mouse brain after transient experimental cerebral ischaemia.

A nested mechanistic sub-study into the effect of tranexamic acid versus placebo on intracranial haemorrhage and cerebral ischaemia in isolated traumatic brain injury: study protocol for a randomised controlled trial (CRASH-3 Trial Intracranial Bleeding Mechanistic Sub-Study [CRASH-3 IBMS])

Background

Tranexamic acid prevents blood clots from breaking down and reduces bleeding. However, it is uncertain whether tranexamic acid is effective in traumatic brain injury. The CRASH-3 trial is a randomised controlled trial that will examine the effect of tranexamic acid (versus placebo) on death and disability in 13,000 patients with traumatic brain injury. The CRASH-3 trial hypothesizes that tranexamic acid will reduce intracranial haemorrhage, which will reduce the risk of death. Although it is possible that tranexamic acid will reduce intracranial bleeding, there is also a potential for harm. In particular, tranexamic acid may increase the risk of cerebral thrombosis and ischaemia. The protocol detailed here is for a mechanistic sub-study nested within the CRASH-3 trial. This mechanistic sub-study aims to examine the effect of tranexamic acid (versus placebo) on intracranial bleeding and cerebral ischaemia.

Methods

The CRASH-3 Intracranial Bleeding Mechanistic Sub-Study (CRASH-3 IBMS) is nested within a prospective, double-blind, multi-centre, parallel-arm randomised trial called the CRASH-3 trial. The CRASH-3 IBMS will be conducted in a cohort of approximately 1000 isolated traumatic brain injury patients enrolled in the CRASH-3 trial. In the CRASH-3 IBMS, brain scans acquired before and after randomisation are examined, using validated methods, for evidence of intracranial bleeding and cerebral ischaemia. The primary outcome is the total volume of intracranial bleeding measured on computed tomography after randomisation, adjusting for baseline bleeding volume. Secondary outcomes include progression of intracranial haemorrhage (from pre- to post-randomisation scans), new intracranial haemorrhage (seen on post- but not pre-randomisation scans), intracranial haemorrhage following neurosurgery, and new focal ischaemic lesions (seen on post-but not pre-randomisation scans). A linear regression model will examine whether receipt of the trial treatment can predict haemorrhage volume. Bleeding volumes and new ischaemic lesions will be compared across treatment groups using relative risks and 95% confidence intervals.

Discussion

The CRASH-3 IBMS will provide an insight into the mechanism of action of tranexamic acid in traumatic brain injury, as well as information about the risks and benefits. Evidence from this trial could inform the management of patients with traumatic brain injury.

Trial registration

The CRASH-3 trial was prospectively registered and the CRASH-3 IBMS is an addition to the original protocol registered at the International Standard Randomised Controlled Trials registry (ISRCTN15088122) 19 July 2011, and ClinicalTrials.gov on 25 July 2011 (NCT01402882).

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-017-2073-6) contains supplementary material, which is available to authorized users.

Neuroprotective effects of AT1 receptor antagonists after experimental ischemic stroke: what is important?

The present study conducted in rats defines the requirements for neuroprotective effects of systemically administered AT1 receptor blockers (ARBs) in acute ischaemic stroke. The inhibition of central effects to angiotensin II (ANG II) after intravenous (i.v.) treatment with candesartan (0.3 and 3 mg/kg) or irbesartan and losartan (3 and 30 mg/kg) was employed to study the penetration of these ARBs across the blood-brain barrier. Verapamil and probenecid were used to assess the role of the transporters, P-glycoprotein and the multidrug resistance-related protein 2, in the entry of losartan and irbesartan into the brain. Neuroprotective effects of i.v. treatment with the ARBs were investigated after transient middle cerebral artery occlusion (MCAO) for 90 min. The treatment with the ARBs was initiated 3 h after the onset of MCAO and continued for two consecutive days. Blood pressure was continuously recorded before and during MCAO until 5.5 h after the onset of reperfusion. The higher dose of candesartan completely abolished, and the lower dose of candesartan and higher doses of irbesartan and losartan partially inhibited the drinking response to intracerebroventricular ANG II. Only 0.3 mg/kg candesartan improved the recovery from ischaemic stroke, and 3 mg/kg candesartan did not exert neuroprotective effects due to marked blood pressure reduction during reperfusion. Both doses of irbesartan and losartan had not any effect on the stroke outcome. An effective, long-lasting blockade of brain AT1 receptors after systemic treatment with ARBs without extensive blood pressure reductions is the prerequisite for neuroprotective effects in ischaemic stroke.

Plasma low-molecular-weight thiol/disulphide homeostasis as an early indicator of global and focal cerebral ischaemia

OBJECTIVE

Recent studies have shown that cerebral ischaemia causes not only local, but also systemic oxidative stress. This leads to oxidation of thiol-containing compounds, including low-molecular-weight thiols (cysteine, glutathione, homocysteine and others). Therefore, the aim of this work was to verify the hypothesis that the thiol/disulphide homeostasis of low-molecular-weight thiols is disturbed in the early stages of cerebral ischaemia.

METHODS

Two experimental rat models of ischaemia were used: a global model of vascular ischaemia (clamping the common carotid arteries + haemorrhage) and focal ischaemia (middle cerebral artery occlusion). The total levels of thiols and their reduced forms were measured before surgery and after 40 minutes of reperfusion (global) or 3 hours (focal) ischaemia.

RESULTS

The global ischaemia model caused a marked (2.5-4 times, P < 0.01) decrease in the plasma thiol/disulphide redox state, and focal ischaemia caused an even larger decrease (30-80 times, P < 0.001).

DISCUSSION

These results suggest that plasma low-molecular-weight thiols are actively involved in oxidation reactions at early stages of cerebral ischaemia; therefore, their reduced forms or redox state may serve as a sensitive indicator of acute cerebrovascular insufficiency.

Connexins and Pannexins in cerebral ischemia

A common cause of mortality and long-term adult disability, cerebral ischemia or brain ischemia imposes a significant health and financial burden on communities worldwide. Cerebral ischemia is a condition that arises from a sudden loss of blood flow and consequent failure to meet the high metabolic demands of the brain. The lack of blood flow initiates a sequelae of cell death mechanisms, including the activation of the inflammatory pathway, which can ultimately result in irreversible brain tissue damage. In particular, Connexins and Pannexins are non-selective channels with a large pore that have shown to play time-dependent roles in the perpetuation of ischaemic injury. This review highlights the roles of Connexin and Pannexin channels in cell death mechanisms as a promising therapeutic target in cerebral ischemia, and in particular connexin hemichannels which may contribute most of the ATP release as a result of ischemia as well as during reperfusion. This article is part of a Special Issue entitled: Gap Junction Proteins edited by Jean Claude Herve.

Creatine Phosphate Administration in Cell Energy Impairment Conditions: A Summary of Past and Present Research

BACKGROUND

Creatine phosphate (CrP) plays a fundamental physiological role by providing chemical energy for cell viability and activity, especially in muscle tissue. Numerous pathological conditions, caused by acute or chronic ischaemic situations, are related to its deficiency. For these reasons, it has been used as a cardioprotective agent in heart surgery and medical cardiology for many years.

OBJECTIVE

This article gives a brief overview of the main characteristics of exogenous CrP.

METHODS

Previous review articles on CrP were screened for relevant information and references. Results from selected studies were reviewed and classified according to the topics in this review article and provided further interesting information on the pharmacological role of this molecule.

RESULTS

Besides CrP's well known cell energy and function restoring properties, new evidence is emerging regarding its antioxidant and anti-apoptotic properties. Use of CrP is well established clinically as an intraoperative and perioperative adjuvant in heart operations (valve replacement, coronary artery bypass grafting, congenital heart defect repair), and as an additional agent in medical cardiology therapy for acute myocardial infarction and acute and chronic heart failure. In particular, there are promising potential new CrP uses in neurology, such as in cerebral ischaemia and hypoxic ischaemic encephalopathy.

CONCLUSIONS

This review article describes the role of CrP treatment in cardiological indications, such as cardioprotection in cardioplegia and in myocardiopathies of various etiopathogenesis, as well as in other clinical indications such as skeletal muscle rehabilitation and neurological conditions.

Dynamic prediction of patient outcomes during ongoing cardiopulmonary resuscitation

PURPOSE

The probability of the return of spontaneous circulation (ROSC) and subsequent favourable outcomes changes dynamically during advanced cardiac life support (ACLS). We sought to model these changes using time-to-event analysis in out-of-hospital cardiac arrest (OHCA) patients.

METHODS

Adult (≥18 years old), non-traumatic OHCA patients without prehospital ROSC were included. Utstein variables and initial arterial blood gas measurements were used as predictors. The incidence rate of ROSC during the first 30min of ACLS in the emergency department (ED) was modelled using spline-based parametric survival analysis. Conditional probabilities of subsequent outcomes after ROSC (1-week and 1-month survival and 6-month neurologic recovery) were modelled using multivariable logistic regression. The ROSC and conditional probability models were then combined to estimate the likelihood of achieving ROSC and subsequent outcomes by providing k additional minutes of effort.

RESULTS

A total of 727 patients were analyzed. The incidence rate of ROSC increased rapidly until the 10th minute of ED ACLS, and it subsequently decreased. The conditional probabilities of subsequent outcomes after ROSC were also dependent on the duration of resuscitation with odds ratios for 1-week and 1-month survival and neurologic recovery of 0.93 (95% CI: 0.90-0.96, p<0.001), 0.93 (0.88-0.97, p=0.001) and 0.93 (0.87-0.99, p=0.031) per 1-min increase, respectively. Calibration testing of the combined models showed good correlation between mean predicted probability and actual prevalence.

CONCLUSIONS

The probability of ROSC and favourable subsequent outcomes changed according to a multiphasic pattern over the first 30min of ACLS, and modelling of the dynamic changes was feasible.

Advances in the understanding of delayed cerebral ischaemia after aneurysmal subarachnoid haemorrhage

Delayed cerebral ischaemia has been described as the single most important cause of morbidity and mortality in patients who survive the initial aneurysmal subarachnoid haemorrhage. Our understanding of the pathophysiology of delayed cerebral ischaemia is meagre at best and the calcium channel blocker nimodipine remains the only intervention to consistently improve functional outcome after aneurysmal subarachnoid haemorrhage. There is substantial evidence to support cerebral vessel narrowing as a causative factor in delayed cerebral ischaemia, but contemporary research demonstrating improvements in vessel narrowing has failed to show improved functional outcomes. This has encouraged researchers to investigate other potential causes of delayed cerebral ischaemia, such as early brain injury, microthrombosis, and cortical spreading depolarisation. Adherence to a common definition of delayed cerebral ischaemia is needed in order to allow easier assessment of studies using multiple different terms. Furthermore, improved recognition of delayed cerebral ischaemia would not only allow for faster treatment but also better assessment of interventions. Finally, understanding nimodipine's mechanism of action may allow us to develop similar agents with improved efficacy.

Influence of previous physical activity on the outcome of patients treated by thrombolytic therapy for stroke

Physical activity prevents stroke and is associated with less severe strokes. The neuroprotective effect in patients treated with intravenous (i.v.) recombinant tissue plasminogen activator (rt-PA), remains uncertain. We aimed at evaluating the relationship between previous physical activity and outcomes in stroke patients treated with i.v. rt-PA. OPHELIE-SPORT was a prospective observational multicenter study conducted in French and Japanese stroke patients treated with i.v. rt-PA. We evaluated the presence, weekly duration (<2, 2-5, >5 h) and intensity (light, moderate, heavy) of previous leisure-time physical activity according to standardized criteria. The primary end-point was an excellent outcome [modified Rankin Scale (mRS) 0-1 or similar to the pre-stroke mRS] after 3 months. Secondary end-points were good outcome (mRS 0-2 or similar to the pre-stroke mRS), and death. Of 519 patients, 74 (14.3 %) had regular physical activity before stroke. They were 14 years younger (p < 0.001), treated 25 min earlier (p = 0.004) and more likely to be men, free of pre-stroke handicap (mRS = 0), atrial fibrillation, arterial hypertension, and diabetes mellitus. National Institutes of Health Stroke Scale scores, at baseline (p = 0.183) and 24 h later (p = 0.203), did not differ between patients with and without physical activity. After adjustment on confounders, there was no association between previous leisure-time physical activity and outcome. Outcomes 3 months after treatment of cerebral ischaemia with i.v. rt-PA are not influenced by previous physical activity.

Near Infrared Light Scattering Changes Following Acute Brain Injury

Acute brain injury (ABI) is associated with changes in near infrared light absorption reflecting haemodynamic and metabolic status via changes in cerebral oxygenation (haemoglobin oxygenation and cytochrome-c-oxidase oxidation). Light scattering has not been comprehensively investigated following ABI and may be an important confounding factor in the assessment of chromophore concentration changes, and/or a novel non-invasive optical marker of brain tissue morphology, cytostructure, hence metabolic status. The aim of this study is to characterize light scattering following adult ABI. Time resolved spectroscopy was performed as a component of multimodal neuromonitoring in critically ill brain injured patients. The scattering coefficient (μ's), absorption coefficient and cerebral haemoglobin oxygen saturation (SO2) were derived by fitting the time resolved data. Cerebral infarction was subsequently defined on routine clinical imaging. In total, 21 patients with ABI were studied. Ten patients suffered a unilateral frontal infarction, and mean μ' s was lower over infarcted compared to non-infarcted cortex (injured 6.9/cm, non-injured 8.2/cm p=0.002). SO2 did not differ significantly between the two sides (injured 69.3%, non-injured 69.0% p=0.7). Cerebral infarction is associated with changes in μ' s which might be a novel marker of cerebral injury and will interfere with quantification of haemoglobin/cytochrome c oxidase concentration. Although further work combining optical and physiological analysis is required to elucidate the significance of these results, μ' s may be uniquely placed as a non-invasive biomarker of cerebral energy failure as well as gross tissue changes.

L-NAME combats excitotoxicity and recuperates neurological deficits in MCAO/R rats

PURPOSE OF RESEARCH

Since, transient focal cerebral ischaemia exhibits detrimental effect not only during the course of ischaemia but also after the onset of reperfusion, the current study is focussed on identifying the appropriate therapeutic time point at which NG-nitro-l-arginine methyl ester (l-NAME) exerts better neuroprotection.

PRINCIPAL RESULTS

Pre-ischaemic administration of l-NAME ameliorated neurological deficits much better than the during ischaemic and post-ischaemic groups. Pre-ischaemic l-NAME has also mitigated glutamate excitotoxicity, increased glutamine synthetase activity, ATP and NAD levels, decreased nitrate/nitrite content, down regulated TNF-α and upregulated IL-10 expressions and reduced the cerebral infarction significantly than the during ischaemic and post-ischaemic groups.

MAJOR CONCLUSION

Current study revealed that l-NAME improved neurological deficit at the pre-ischaemic state in transient focal cerebral ischaemia and has also significantly ameliorated glutamate excitotoxicity. Though l-NAME showed neuroprotective effects when administered at during and post-ischaemia (during reperfusion), it exerts considerable neuroprotection when administered pre-ischaemically.

The combination of astragalus membranaceus and ligustrazine ameliorates micro-haemorrhage by maintaining blood-brain barrier integrity in cerebrally ischaemic rats

ETHNOPHARMACOLOGICAL RELEVANCE

Haemorrhagic transformation is an asymptomatic event that frequently occurs after following ischaemic stroke, particularly when pharmaceutical thrombolysis is used. However, the mechanism responsible for haemorrhagic transformation remains unknown, and therapeutics have not been identified. In this study, we administered a combination of astragalus membranaceus and ligustrazine to rats with cerebral ischaemia that had undergone thrombolysis. We analysed the effect of this combination on the attenuation of haemorrhagic transformation and the maintenance of blood-brain barrier integrity.

METHODS

A rat model of focal cerebral ischaemia was induced with autologous blood clot injections. Thrombolysis was performed via the intravenous injection of rt-PA. Astragalus membranaceus, ligustrazine or a combination of Astragalus membranaceus and ligustrazine was administered immediately after the clot injection. The cerebral infarct area, neurological deficits, blood-brain barrier integrity, and cerebral haemorrhage status were determined after 3, 6 and 24h of ischaemia. The ultrastructure of the blood-brain barrier was examined with a transmission electron microscope. The expression of tight junction proteins, including claudin-1, claudin-5, occludin, and zonula occludens-1, and matrix metallopeptidase-9 activation was further evaluated in terms of their roles in the protective effects of the combination drug on the integrity of the blood-brain barrier.

RESULTS

Ischaemia-induced Evans blue leakage and cerebral haemorrhage were markedly reduced in the combination drug-treated rats compared to the rats treated with either astragalus membranaceus or ligustrazine alone (p<0.05). The disruption of the ultrastructure of the blood-brain barrier and the neurological deficits were ameliorated by the combination treatment (p<0.05). The reductions in the expression of laudin-1, claudin-5, occludin, and ZO-1 were smaller in the rats that received the combination treatment. In addition, MMP-9 activity was suppressed in the combination-treated rats compared to the controls (p<0.05).

CONCLUSIONS

Treatment with a combination of astragalus membranaceus and ligustrazine alleviated ischaemia-induced micro-haemorrhage transformation by maintaining the integrity of the blood-brain barrier.