Erythrocytes and delayed brain edema formation following intracerebral hemorrhage in rats

A novel ferroptosis inhibitor phenothiazine derivative reduces cell death and alleviates neurological impairments after cerebral hemorrhage

The precise etiology of brain injury induced by intracerebral hemorrhage (ICH) remains unclear. Currently, there are no effective therapeutic options available to slow down or prevent the progression of the disease. An increasing body of evidence suggests that ferroptosis plays a significant role in the development of injury related to ICH. Furthermore, pharmacological inhibition of ferroptosis has been identified as a promising therapeutic target for ICH injury. The compound 2-(1-(4-(4-methylpiperazin-1-yl)phenyl)ethyl)-10H-phenothiazine (compound-51), a derivative of promethazine, has been demonstrated to exhibit anti-ferroptosis and antioxidant properties. The aim of this study is to investigate the role and mechanism of action of compound-51 in a rat model of ICH. The in vivo experiments demonstrated that compound-51 significantly alleviated neurological impairments, reduced brain edema, and decreased hematoma volume. At the cellular level, compound-51 was observed to significantly enhance cellular survival and inhibit ferroptosis. Furthermore, compound-51 demonstrated a more pronounced therapeutic effect than Fer-1, without causing any injury to the heart, kidney, or liver. In vitro experiments demonstrated that compound-51 significantly increased cell viability and intracellular GPX4 levels, while reducing lipid peroxidation and oxidized glutathione levels. Collectively, these findings indicate that compound-51 exhibits a pronounced anti-ferroptosis function and alleviates neurological impairments in an ICH model, suggesting its potential as a new therapeutic agent for the treatment of ICH.

Mitigating mitochondrial dysfunction and neuroinflammation by hematoma aspiration in a new surgical model for severe intracerebral hemorrhage

BACKGROUND

Intracerebral hemorrhage (ICH) is associated with a large hematoma that causes compression, increased intracranial pressure (IICP), midline shift, and brain herniation, and may ultimately lead to death. Urgent surgical removal of the large hematoma can ameliorate these injuries, which would be life-saving, but has not improved clinical outcome. A suitable animal model that mimics the clinically relevant human severe ICH injury requiring surgical hematoma evacuation is urgently needed. Here, we established a novel model of severe ICH in rats allowing aspiration of the hematoma and studying the effects of mitochondrial dysfunction in ICH.

METHODS

Severe ICH was induced by intra-striatal injection of 0.6 U of collagenase in 3 μL sterile saline over 15 min. Aspiration of approximately 75 % of the total hematoma was performed 6 h after induction of severe ICH. The effects of hematoma aspiration on hematoma volume, mortality, oxidative stress, ATP levels, mitochondrial dysfunction, and neurological function were measured in rats.

RESULTS

Severe ICH induction increased hematoma volume, neurological deficits, and mortality. Hematoma aspiration abolished mortality and significantly reduced hematoma volume, and neurological deficits. In addition, hematoma aspiration ameliorated the pronounced mitochondrial dysfunction responsible for the failure of energy production and excessive oxidative stress associated with severe hemorrhagic injury. Hematoma aspiration also modulated mitochondrial biogenesis and mitophagy, thereby promoting mitochondrial homeostasis. Markers of neuroinflammation, including iNOS, MMP9, and MPO, were elevated in severe ICH but attenuated by hematoma aspiration.

CONCLUSION

This study established an animal model of severe ICH and provides valuable insights into the complex pathogenesis of severe ICH. The results showed that hematoma aspiration effectively ameliorates mitochondrial dysfunction, oxidative stress, and neuroinflammation, highlighting its potential as a therapeutic intervention.

Human platelet lysate: a potential therapeutic for intracerebral hemorrhage

Intracerebral hemorrhage (ICH) is a major public health challenge worldwide, and is associated with elevated rates of mortality, disability, and morbidity, especially in low- and middle-income nations. However, our knowledge of the detailed molecular processes involved in ICH remains insufficient, particularly those involved in the secondary injury stage, resulting in a lack of effective treatments for ICH. Human platelet lysates (HPL) are abundant in bioactive factors, and numerous studies have demonstrated their beneficial effects on neurological diseases, including their anti-neuroinflammatory ability, anti-oxidant effects, maintenance of blood-brain barrier integrity, and promotion of neurogenesis. In this review, we thoroughly explore the potential of HPL for treating ICH from three critical perspectives: the rationale for selecting HPL as a treatment for ICH, the mechanisms through which HPL contributes to ICH management, and the additional measures necessary for HPL as a treatment for ICH. We elucidate the role of platelets in ICH pathophysiology and highlight the limitations of the current treatment options and advancements in preclinical research on the application of HPL in neurological disorders. Furthermore, historical developments and preparation methods of HPL in the field of biomedicine are discussed. Additionally, we summarize the bioactive molecules present in HPL and their potential therapeutic effects in ICH. Finally, we outline the issues that must be addressed regarding utilizing HPL as a treatment modality for ICH.

Morphological characteristics of CT blend sign predict hematoma expansion and outcomes in intracerebral hemorrhage in elderly patients

Background and purpose

The underlying basis of the blend sign on brain computed tomography (CT) in patients with intracerebral hemorrhage (ICH) is unclear. Few studies have examined the morphological alterations in the CT blend sign in ICH. Therefore, we assessed changes in the CT blend sign and their association with hematoma expansion (HE) and adverse outcomes in ICH patients.

Methods

We recorded the clinical and radiographic parameters of patients with ICH and blend sign on brain CT. The patients were categorized into two groups, with changes in the relatively hypoattenuating region of the blend sign (CHB group) and with no changes in the relatively hypoattenuating region of the blend sign (NHB groups). We performed univariate and multivariate logistic regression analyses to examine the correlations between CHB and HE and poor outcomes. Furthermore, receiver operating characteristic curve analysis was used to confirm the predictive power of CHB.

Results

In total, 183 patients were included in the study, of whom 74 (40.4%) demonstrated changes in the hypoattenuating region of the blend sign, whereas 109 (59.6%) did not. Compared with the NHB group, patients in the CHB group exhibited significantly higher levels of HE and adverse outcomes. After adjustment for confounding factors, CHB was independently associated with HE (odds ratio, 19.401 [95% CI, 7.217-52.163]; p < 0.001) and poor 3-month outcomes (odds ratio, 2.638 [95% CI, 1.391-5.003]; p = 0.003) in the multivariate analysis. The sensitivity, specificity, positive predictive value, and negative predictive value of CHB for predicting HE were 0.877, 0.768, 0.791, and 0.862, respectively, whereas these values for predicting poor outcomes were 0.789, 0.641, 0.688, and 0.752, respectively.

Conclusion

Changes of a hypoattenuating region within the blend sign have good predictive accuracy for HE and short-term adverse outcomes in elderly patients with ICH.

Clinical trial registration

ClinicalTrials.gov, NCT05548530.

Ion Channel Dysregulation Following Intracerebral Hemorrhage

Injury to the brain after intracerebral hemorrhage (ICH) results from numerous complex cellular mechanisms. At present, effective therapy for ICH is limited and a better understanding of the mechanisms of brain injury is necessary to improve prognosis. There is increasing evidence that ion channel dysregulation occurs at multiple stages in primary and secondary brain injury following ICH. Ion channels such as TWIK-related K+ channel 1, sulfonylurea 1 transient receptor potential melastatin 4 and glutamate-gated channels affect ion homeostasis in ICH. They in turn participate in the formation of brain edema, disruption of the blood-brain barrier, and the generation of neurotoxicity. In this review, we summarize the interaction between ions and ion channels, the effects of ion channel dysregulation, and we discuss some therapeutics based on ion-channel modulation following ICH.

Asymptomatic Intracerebral Hemorrhage Following Endovascular Stroke Therapy Is Not Benign: A Systematic Review and Meta-Analysis

BACKGROUND

Asymptomatic intracerebral hemorrhage (aICH) occurs in approximately 35% of patients with acute ischemic stroke after endovascular thrombectomy. Unlike symptomatic ICH, studies evaluating the effect of aICH on outcomes have been inconclusive. We performed a systematic review and meta-analysis to evaluate the long-term effects of postendovascular thrombectomy aICH.

METHODS AND RESULTS

The meta-analysis protocol was submitted to the International Prospective Register of Systematic Reviews a priori. PubMed, Scopus, and Web of Science were searched from inception through September 2023, yielding 312 studies. Two authors independently reviewed all abstracts. Included studies contained adult patients with ischemic stroke undergoing endovascular thrombectomy with follow-up imaging assessment of ICH reporting comparative outcomes according to aICH versus no ICH. After screening, 60 papers were fully reviewed, and 10 studies fulfilled inclusion criteria (n=5723 patients total, 1932 with aICH). Meta-analysis was performed using Cochrane RevMan v5.4. Effects were estimated by a random-effects model to estimate summary odds ratio (OR) of the effect of aICH versus no ICH on primary outcomes of 90-day modified Rankin Scale 3 to 6 and mortality. The presence of aICH was associated with a higher odds of 90-day mRS 3 to 6 (OR, 2.17 [95% CI, 1.81-2.60], P<0.0001, I2 46% Q 19.15) and mortality (OR, 1.72 [95% CI, 1.17-2.53], P:0.005, I2 79% Q 27.59) compared with no ICH. This difference was maintained following subgroup analysis according to hemorrhage classification and recanalization status.

CONCLUSIONS

The presence of aICH is associated with worse 90-day functional outcomes and higher mortality. Further studies to evaluate the factors predicting aICH and treatments aimed at reducing its occurrence are warranted.

Targeting Pro-Oxidant Iron with Exogenously Administered Apotransferrin Provides Benefits Associated with Changes in Crucial Cellular Iron Gate Protein TfR in a Model of Intracerebral Hemorrhagic Stroke in Mice

We have previously demonstrated that the post-stroke administration of iron-free transferrin (apotransferrin, ATf) is beneficial in different models of ischemic stroke (IS) through the inhibition of the neuronal uptake of pro-oxidant iron. In the present study, we asked whether ATf is safe and also beneficial when given after the induction of intracerebral hemorrhage (ICH) in mice, and investigated the underlying mechanisms. We first compared the main iron actors in the brain of IS- or collagenase-induced ICH mice and then obtained insight into these iron-related proteins in ICH 72 h after the administration of ATf. The infarct size of the IS mice was double that of hemorrhage in ICH mice, but both groups showed similar body weight loss, edema, and increased ferritin and transferrin levels in the ipsilateral brain hemisphere. Although the administration of human ATf (hATf) to ICH mice did not alter the hemorrhage volume or levels of the classical ferroptosis GPX4/system xc- pathways, hATf induced better neurobehavioral performance, decreased 4-hydroxynonenal levels and those of the second-generation ferroptosis marker transferrin receptor (TfR), and restored the mRNA levels of the recently recognized cytosolic iron chaperone poly(RC) binding protein 2. In addition, hATf treatment lowered the ICH-induced increase in both endogenous mouse transferrin mRNA levels and the activation of caspase-2. In conclusion, hATf treatment provides neurobehavioral benefits post-ICH associated with the modulation of iron/oxidative players.

Revisiting the role of the complement system in intracerebral hemorrhage and therapeutic prospects

Intracerebral hemorrhage (ICH) is a stroke subtype characterized by non-traumatic rupture of blood vessels in the brain, resulting in blood pooling in the brain parenchyma. Despite its lower incidence than ischemic stroke, ICH remains a significant contributor to stroke-related mortality, and most survivors experience poor outcomes that significantly impact their quality of life. ICH has been accompanied by various complex pathological damage, including mechanical damage of brain tissue, hematoma mass effect, and then leads to inflammatory response, thrombin activation, erythrocyte lysis, excitatory amino acid toxicity, complement activation, and other pathological changes. Accumulating evidence has demonstrated that activation of complement cascade occurs in the early stage of brain injury, and the excessive complement activation after ICH will affect the occurrence of secondary brain injury (SBI) through multiple complex pathological processes, aggravating brain edema, and pathological brain injury. Therefore, the review summarized the pathological mechanisms of brain injury after ICH, specifically the complement role in ICH, and its related pathological mechanisms, to comprehensively understand the specific mechanism of different complements at different stages after ICH. Furthermore, we systematically reviewed the current state of complement-targeted therapies for ICH, providing a reference and basis for future clinical transformation of complement-targeted therapy for ICH.

A systematic review and meta-analysis on the efficacy of glibenclamide in animal models of intracerebral hemorrhage

Intracerebral hemorrhage (ICH) is a devastating stroke with many mechanisms of injury. Edema worsens outcome and can lead to mortality after ICH. Glibenclamide (GLC), a sulfonylurea 1- transient receptor potential melastatin 4 (Sur1-Trpm4) channel blocker, has been shown to attenuate edema in ischemic stroke models, raising the possibility of benefit in ICH. This meta-analysis synthesizes current pre-clinical (rodent) literature regarding the efficacy of post-ICH GLC administration (vs. vehicle controls) on behaviour (i.e., neurological deficit, motor, and memory outcomes), edema, hematoma volume, and injury volume. Six studies (5 in rats and 1 in mice) were included in our meta-analysis (PROSPERO registration = CRD42021283614). GLC significantly improved behaviour (standardized mean difference (SMD) = -0.63, [-1.16, -0.09], n = 70-74) and reduced edema (SMD = -0.91, [-1.64, -0.18], n = 70), but did not affect hematoma volume (SMD = 0.0788, [-0.5631, 0.7207], n = 18-20), or injury volume (SMD = 0.2892, [-0.4950, 1.0734], n = 24). However, these results should be interpreted cautiously. Findings were conflicted with 2 negative and 4 positive reports, and Egger regressions indicated missing negative edema data (p = 0.0001), and possible missing negative behavioural data (p = 0.0766). Experimental quality assessed via the SYRCLE and CAMARADES checklists was concerning, as most studies demonstrated high risks of bias. Studies were generally low-powered (e.g., average n = 14.4 for behaviour), and future studies should employ sample sizes of 41 to detect our observed effect size in behaviour and 33 to detect our observed effect in edema. Overall, missing negative studies, low study quality, high risk of bias, and incomplete attention to key recommendations (e.g., investigating female, aged, and co-morbid animals) suggest that further high-powered confirmatory studies are needed before conclusive statements about GLC's efficacy in ICH can be made, and before further clinical trials are performed.

Exploring the Neuroprotective Effects of Spirulina platensis: Insights Into Hemorrhagic Volume and Histological Outcomes

Background Hemorrhagic events can result in significant neurological damage, and identifying effective strategies for neuroprotection is crucial. Several studies have directed their attention to the alterations in perilesional parenchymal tissue. These investigations have sought to modify ischemic and metabolic changes by utilizing potential neuroprotective agents and to develop strategies that effectively mitigate secondary perilesional neuronal damage. By gaining a deeper understanding of its mechanisms and efficacy, Spirulina platensis can emerge as a promising therapeutic intervention for various neurological disorders. Methodology This controlled and blinded experimental study was conducted on adult male Wistar rats. The rats were divided into the treatment group, which received Spirulina platensis extract for 30 days before the hemorrhagic event, and the control group, where all animals underwent the same experimental hemorrhage model using collagenase. Each group was divided into the following three subgroups based on the sacrifice time: six hours, 24 hours, and 30 days. The brain section with the largest hemorrhage volume was selected for histological analysis. The number of viable neurons was analyzed in the perilesional zone and the cortical fields along the puncture trajectory. Neurofunctional evaluations were conducted on animals sacrificed 15 and 30 days after the procedure. Results Initial analysis showed no significant difference in viable neurons between groups (p = 0.63). Still, after 24 hours, the treatment group had a significantly higher number of viable neurons per peripheral fields (18.5) compared to the control group (13.4; p < 0.05). Neurofunctional tests at 15 days indicated a trend toward significance in absolute discrimination (p = 0.054), with the control group showing higher mean values (5.5, SD = 3.1) than the treatment group (-1, SD = 5.1). The discrimination index exhibited a significant difference (p < 0.01), with higher mean values in the control group (0.59, SD = 0.34) compared to the treatment group (-0.05, SD = 0.21). No significant differences were found in other neurofunctional parameters at this time point. At 30 days, no significant differences were observed in absolute discrimination, discrimination index, contralateral paw elevation, rearing time, and wire hanging time test (p > 0.1); however, the treatment group presented a better motor performance in the open field test (14.2, SD = 9.02) compared to the control group (5.25, SD = 2.06), approaching significance (p = 0.06). Conclusions The group treated with Spirulina platensis demonstrated significantly more viable neurons in the perilesional fields 24 hours after the induced hemorrhage. The treatment group also had a relatively better motor performance in the open field test 30 days after the hemorrhage (p = 0.06). These findings suggest a potential neuroprotection effect and warrant further investigations to explore the effects of Spirulina platensis and its active component phycocyanin in acute neurological conditions.

Brain edema formation and therapy after intracerebral hemorrhage

Intracerebral hemorrhage (ICH) accounts for about 10% of all strokes in the United States of America causing a high degree of disability and mortality. There is initial (primary) brain injury due to the mechanical disruption caused by the hematoma. There is then secondary injury, triggered by the initial injury but also the release of various clot-derived factors (e.g., thrombin and hemoglobin). ICH alters brain fluid homeostasis. Apart from the initial hematoma mass, ICH causes blood-brain barrier disruption and parenchymal cell swelling, which result in brain edema and intracranial hypertension affecting patient prognosis. Reducing brain edema is a critical part of post-ICH care. However, there are limited effective treatment methods for reducing perihematomal cerebral edema and intracranial pressure in ICH. This review discusses the mechanisms underlying perihematomal brain edema formation, the effects of sex and age, as well as how edema is resolved. It examines progress in pharmacotherapy, particularly focusing on drugs which have been or are currently being investigated in clinical trials.

Animal models for the study of intracranial hematomas (Review)

Intracranial hematomas (ICH) are a frequent condition in neurosurgical and neurological practices, with several mechanisms of primary and secondary injury. Experimental research has been fundamental for the understanding of the pathophysiology implicated with ICH and the development of therapeutic interventions. To date, a variety of different animal approaches have been described that consider, for example, the ICH evolutive phase, molecular implications and hemodynamic changes. Therefore, choosing a test protocol should consider the scope of each particular study. The present review summarized investigational protocols in experimental research on the subject of ICH. With this subject, injection of autologous blood or bacterial collagenase, inflation of intracranial balloon and avulsion of cerebral vessels were the models identified. Rodents (mice) and swine were the most frequent species used. These different models allowed improvements on the understanding of intracranial hypertension establishment, neuroinflammation, immunology, brain hemodynamics and served to the development of therapeutic strategies.

Colchicine pre-treatment and post-treatment does not worsen bleeding or functional outcome after collagenase-induced intracerebral hemorrhage

Patients with intracerebral hemorrhage (ICH) are at increased risk for major ischemic cardiovascular and cerebrovascular events. However, the use of preventative antithrombotic therapy can increase the risk of ICH recurrence and worsen ICH-related outcomes. Colchicine, an anti-inflammatory agent, has the potential to mitigate inflammation-related atherothrombosis and reduce the risk of ischemic vascular events. Here we investigated the safety and efficacy of colchicine when used both before and acutely after ICH. We predicted that daily colchicine administration would not impact our safety measures but would reduce brain injury and improve functional outcomes associated with inflammation reduction. To test this, 0.05 mg/kg colchicine was given orally once daily to rats either before or after they were given a collagenase-induced striatal ICH. We assessed neurological impairments, intra-parenchymal bleeding, Perls positive cells, and brain injury to gauge the therapeutic impact of colchicine on brain injury. Colchicine did not significantly affect bleeding (average = 40.7 μL) at 48 hrs, lesion volume (average = 24.5 mm³) at 14 days, or functional outcome (median neurological deficit scale score at 2 days post-ICH = 4, i.e., modest deficits) from 1–14 days after ICH. Colchicine reduced the volume of Perls positive cells in the perihematomal zone, indicating a reduction in inflammation. Safety measures (body weight, food consumption, water consumption, hydration, body temperature, activity, and pain) were not affected by colchicine. Although colchicine did not confer neuroprotection or functional benefit, it was able to reduce perihematomal inflammation after ICH without increasing bleeding. Thus, our findings suggest that colchicine treatment is safe, unlikely to worsen bleeding, and is unlikely but may reduce secondary injury after an ICH if initiated early post ICH to reduce the risk of ischemic vascular events. These results are informative for the ongoing CoVasc-ICH phase II randomized trial (NCT05159219).

The Fate of Erythrocytes after Cerebral Hemorrhage

After a cerebral hemorrhage (intracerebral, subarachnoid, and intraventricular), extravasated blood contributes to both initial brain injury, via physical disruption and mass effect, and secondary injury, through the release of potentially neurotoxic and pro-inflammatory factors such as hemoglobin, iron, and peroxiredoxin-2. Erythrocytes are a major blood component and are a source of such damaging factors. Erythrolysis after cerebral hemorrhage releases potential neurotoxins, contributing to brain injury and edema. Alternatively, erythrocyte phagocytosis via microglia or macrophages may limit the spill of neurotoxins therefore limiting subsequent brain injury. The aim of this review is to discuss the process of phagocytosis of erythrocytes by microglia or macrophages after cerebral hemorrhage, the effect of erythrolysis on brain injury, novel mechanisms of erythrocyte and phagocyte egress from the brain, and exciting new targets in this pathway to attenuate brain injury. Understanding the fate of erythrocytes after cerebral hemorrhage may uncover additional potential interventions for clinical translational research.

The Protective Effects of Acetazolamide Against Homocysteine-Induced Blood-Brain-Barrier Disruption by Regulating the Activation of the Wnt/β-Catenin Signaling Pathway

Acetazolamide (AZA) is a carbonic anhydrase inhibitor (CAI) with neuroprotective effects. Hyperhomocysteinemia is associated with blood-brain-barrier (BBB) disruption in brain disorders. A previous study indicated that AZA might have a new role in brain disorders. However, its function in hyperhomocysteinemia-related BBB disruption has not been reported. Here, we aim to clarify the role of AZA in homocysteine (Hcy)-mediated BBB dysfunction using both in vivo and in vitro assays. We found that AZA improved memory and cognitive function, and reduced brain edema in Hcy-stimulated hyperhomocysteinemia model rats. This protective effect of AZA on hyperhomocysteinemia rats was accompanied by improved BBB permeability and increased expression levels of the tight junction proteins, occludin, and claudin-5. The in vitro assay results show that AZA prevented Hcy-induced cell injury and attenuated the increased permeability in Hcy-treated bEnd.3 brain endothelial cells. The Hcy-induced decrease in occludin and claudin-5, and increase in MMP-2 and MMP-9 expression levels were attenuated by AZA in bEnd.3 cells. Moreover, the Hcy-induced downregulation of the Wnt/β-catenin signaling pathway in bEnd.3 cells was abolished by AZA. Inhibition of Wnt/β-catenin by ICG-001 reversed the protective effects of AZA in Hcy-treated bEnd.3 cells. We also prove that this process is mediated by WTAP. These findings suggest that acetazolamide mitigated the Hcy-induced compromised brain vascular endothelial integrity by regulating the activation of the Wnt/β-catenin signaling pathway.

Essential topics about the imaging diagnosis and treatment of Hemorrhagic Stroke: a comprehensive review of the 2022 AHA guidelines

Intracerebral hemorrhage (ICH) is a severe stroke with a high death rate (40 % mortality). The prevalence of hemorrhagic stroke has increased globally, with changes in the underlying cause over time as anticoagulant use and hypertension treatment have improved. The fundamental etiology of ICH and the mechanisms of harm from ICH, particularly the complex interaction between edema, inflammation, and blood product toxicity, have been thoroughly revised by the American Heart Association (AHA) in 2022. Although numerous trials have investigated the best medicinal and surgical management of ICH, there is still no discernible improvement in survival and functional tests. Small vessel diseases, such as cerebral amyloid angiopathy (CAA) or deep perforator arteriopathy (hypertensive arteriopathy), are the most common causes of spontaneous non-traumatic intracerebral hemorrhage (ICH). Even though ICH only causes 10-15% of all strokes, it contributes significantly to morbidity and mortality, with few acute or preventive treatments proven effective. Current AHA guidelines acknowledge up to 89% sensitivity for unenhanced brain CT and 81% for brain MRI. The imaging findings of both methods are helpful for initial diagnosis and follow-up, sometimes necessary a few hours after admission, especially for detecting hemorrhagic transformation or hematoma expansion. This review summarized the essential topics on hemorrhagic stroke epidemiology, risk factors, physiopathology, mechanisms of injury, current management approaches, findings in neuroimaging, goals and outcomes, recommendations for lifestyle modifications, and future research directions ICH. A list of updated references is included for each topic.

Activation of P2X4 receptor exacerbates acute brain injury after intracerebral hemorrhage

Introduction

Intracerebral hemorrhage (ICH) accounts for 10%–15% of all strokes and culminates in high mortality and disability. After ICH, brain injury is initiated by the mass effect of hematoma, followed by secondary cytotoxic injury from dying brain cells, hematoma disintegration, and cascading brain immune response. However, the molecular mechanism of secondary cytotoxic brain injury in ICH is not completely understood. The sensitive purinergic receptor, P2X4 receptor (P2X4R), was known to recognize extracellular free ATP released by dying cells during tissue injury.

Aims

In this study, we aim to understand the role of P2X4R in acute brain injury triggered by ICH.

Results

In this study, we found that the sensitive purinergic receptor, P2X4R, was upregulated in the brain of patients with ICH as well as in a mouse model of ICH induced by collagenase injection. P2X4R blockage with the specific inhibitor 5‐BDBD attenuated brain injury in ICH mice by significantly reducing brain edema, blood–brain barrier leakage, neural death, and ultimately acute neurodeficits. Further study indicated that the protective effect of P2X4R inhibition is related to decreased pro‐inflammatory activity of microglia and recruitment of peripheral immune cells into the hemorrhagic brain.

Conclusions

These results suggest that the P2X4 receptor is activated by ICH stimuli which worsen brain injury following ICH.

Secondary Brain Injury by Oxidative Stress After Cerebral Hemorrhage: Recent Advances

Intracerebral hemorrhage (ICH) is a clinical syndrome in which blood accumulates in the brain parenchyma because of a nontraumatic rupture of a blood vessel. Because of its high morbidity and mortality rate and the lack of effective therapy, the treatment of ICH has become a hot research topic. Meanwhile, Oxidative stress is one of the main causes of secondary brain injury(SBI) after ICH. Therefore, there is a need for an in-depth study of oxidative stress after ICH. This review will discuss the pathway and effects of oxidative stress after ICH and its relationship with inflammation and autophagy, as well as the current antioxidant therapy for ICH with a view to deriving better therapeutic tools or targets for ICH.

Iron Neurotoxicity and Protection by Deferoxamine in Intracerebral Hemorrhage

Intracerebral hemorrhage (ICH) is a subtype of stroke that is characterized by high morbidity and mortality, for which clinical outcome remains poor. An extensive literature indicates that the release of ferrous iron from ruptured erythrocytes in the hematoma is a key pathogenic factor in ICH-induced brain injury. Deferoxamine is an FDA-approved iron chelator that has the capacity to penetrate the blood-brain barrier after systemic administration and binds to iron. Previous animal studies have shown that deferoxamine attenuates ICH-induced brain edema, neuronal death, and neurological deficits. This review summarizes recent progress of the mechanisms by which deferoxamine may alleviate ICH and discusses further studies on its clinical utility.

Cerebral Hemorrhage: Pathophysiology, Treatment, and Future Directions

Intracerebral hemorrhage (ICH) is a devastating form of stroke with high morbidity and mortality. This review article focuses on the epidemiology, cause, mechanisms of injury, current treatment strategies, and future research directions of ICH. Incidence of hemorrhagic stroke has increased worldwide over the past 40 years, with shifts in the cause over time as hypertension management has improved and anticoagulant use has increased. Preclinical and clinical trials have elucidated the underlying ICH cause and mechanisms of injury from ICH including the complex interaction between edema, inflammation, iron-induced injury, and oxidative stress. Several trials have investigated optimal medical and surgical management of ICH without clear improvement in survival and functional outcomes. Ongoing research into novel approaches for ICH management provide hope for reducing the devastating effect of this disease in the future. Areas of promise in ICH therapy include prognostic biomarkers and primary prevention based on disease pathobiology, ultra-early hemostatic therapy, minimally invasive surgery, and perihematomal protection against inflammatory brain injury.

Longitudinal Observation of Asymmetric Iron Deposition in an Intracerebral Hemorrhage Model Using Quantitative Susceptibility Mapping

Quantitative susceptibility mapping (QSM) is used to obtain quantitative magnetic susceptibility maps of materials from magnitude and phase images acquired by three-dimensional gradient-echo using inverse problem-solving. Few preclinical studies have evaluated the intracerebral hemorrhage (ICH) model and asymmetric iron deposition. We created a rat model of ICH and compared QSM and conventional magnetic resonance imaging (MRI) during the longitudinal evaluation of ICH. Collagenase was injected in the right striatum of 12-week-old Wistar rats. QSM and conventional MRI were performed on days 0, 1, 7, and 28 after surgery using 7-Tesla MRI. Susceptibility, normalized signal value, and area of the hemorrhage site were statistically compared during image analysis. Susceptibility decreased monotonically up to day 7 but increased on day 28. Other imaging methods showed a significant increase in signal from day 0 to day 1 but a decreasing trend after day 1. During the area evaluation, conventional MRI methods showed an increase from day 0 to day 1; however, decreases were observed thereafter. QSM showed a significant increase from day 0 to day 1. The temporal evaluation of ICH by QSM suggested the possibility of detecting of asymmetric iron deposition for normal brain site.

Glibenclamide does not improve outcome following severe collagenase-induced intracerebral hemorrhage in rats

Intracerebral hemorrhage (ICH) is a devastating insult with few effective treatments. Edema and raised intracranial pressure contribute to poor outcome after ICH. Glibenclamide blocks the sulfonylurea 1 transient receptor potential melastatin 4 (Sur1-Trpm4) channel implicated in edema formation. While glibenclamide has been found to improve outcome and reduce mortality in animal models of severe ischemic stroke, in ICH the effects are less clear. In our previous study, we found no benefit after a moderate-sized bleed, while others have reported benefit. Here we tested the hypothesis that glibenclamide may only be effective in severe ICH, where edema is an important contributor to outcome. Glibenclamide (10 μg/kg loading dose, 200 ng/h continuous infusion) was administered 2 hours post-ICH induced by collagenase injection into the striatum of adult rats. A survival period of 24 hours was maintained for experiments 1-3, and 72 hours for experiment 4. Glibenclamide did not affect hematoma volume (~81 μL) or other safety endpoints (e.g., glucose levels), suggesting the drug is safe. However, glibenclamide did not lessen striatal edema (~83% brain water content), ionic dyshomeostasis (Na+, K+), or functional impairment (e.g., neurological deficits (median = 10 out of 14), etc.) at 24 hours. It also did not affect edema at 72 h (~86% brain water content), or overall mortality rates (25% and 29.4% overall in vehicle vs. glibenclamide-treated severe strokes). Furthermore, glibenclamide appears to worsen cytotoxic edema in the peri-hematoma region (cell bodies were 46% larger at 24 h, p = 0.0017), but no effect on cell volume or density was noted elsewhere. Overall, these findings refute our hypothesis, as glibenclamide produced no favorable effects following severe ICH.

When the Blood Hits Your Brain: The Neurotoxicity of Extravasated Blood

Hemorrhage in the central nervous system (CNS), including intracerebral hemorrhage (ICH), intraventricular hemorrhage (IVH), and aneurysmal subarachnoid hemorrhage (aSAH), remains highly morbid. Trials of medical management for these conditions over recent decades have been largely unsuccessful in improving outcome and reducing mortality. Beyond its role in creating mass effect, the presence of extravasated blood in patients with CNS hemorrhage is generally overlooked. Since trials of surgical intervention to remove CNS hemorrhage have been generally unsuccessful, the potent neurotoxicity of blood is generally viewed as a basic scientific curiosity rather than a clinically meaningful factor. In this review, we evaluate the direct role of blood as a neurotoxin and its subsequent clinical relevance. We first describe the molecular mechanisms of blood neurotoxicity. We then evaluate the clinical literature that directly relates to the evacuation of CNS hemorrhage. We posit that the efficacy of clot removal is a critical factor in outcome following surgical intervention. Future interventions for CNS hemorrhage should be guided by the principle that blood is exquisitely toxic to the brain.

The Story of Intracerebral Hemorrhage: From Recalcitrant to Treatable Disease

This invited special report is based on an award presentation at the World Stroke Organization/European Stroke Organization Conference in November of 2020 outlining progress in the acute management of intracerebral hemorrhage (ICH) over the past 35 years. ICH is the second most common and the deadliest type of stroke for which there is no scientifically proven medical or surgical treatment. Prospective studies from the 1990s onward have demonstrated that most growth of spontaneous ICH occurs within the first 2 to 3 hours and that growth of ICH and resulting volumes of ICH and intraventricular hemorrhage are modifiable factors that can improve outcome. Trials focusing on early treatment of elevated blood pressure have suggested a target systolic blood pressure of 140 mm Hg, but none of the trials were positive by their primary end point. Hemostatic agents to decrease bleeding in spontaneous ICH have included desmopressin, tranexamic acid, and rFVIIa (recombinant factor VIIa) without clear benefit, and platelet infusions which were associated with harm. Hemostatic agents delivered within the first several hours have the greatest impact on growth of ICH and potentially on outcome. No large Phase III surgical ICH trial has been positive by primary end point, but pooled analyses suggest that earlier ICH removal is more likely to be beneficial. Recent trials emphasize maximization of clot removal and minimizing brain injury from the surgical approach. The future of ICH therapy must focus on delivery of medical and surgical therapies as soon as possible if we are to improve outcomes.

Effect of hemopexin treatment on outcome after intracerebral hemorrhage in mice

Heme release from hemoglobin may contribute to secondary injury after intracerebral hemorrhage (ICH). The primary endogenous defense against heme toxicity is hemopexin, a 57 kDa glycoprotein that is depleted in the CNS after hemorrhagic stroke. We hypothesized that systemic administration of exogenous hemopexin would reduce perihematomal injury and improve outcome after experimental ICH. Intraperitoneal treatment with purified human plasma hemopexin beginning 2 h after striatal ICH induction and repeated daily for the following two days reduced blood-brain barrier disruption and cell death at 3 days. However, it had no effect on neurological deficits at 4 or 7 days or striatal cell viability at 8 days. Continuous daily hemopexin administration had no effect on striatal heme content at 3 or 7 days, and did not attenuate neurological deficits, inflammatory cell infiltration, or perihematomal cell viability at 8 days. These results suggest that systemic hemopexin treatment reduces early injury after ICH, but this effect is not sustained, perhaps due to an imbalance between striatal tissue heme and hemopexin content at later time points. Future studies should investigate its effect when administered by methods that more efficiently target CNS delivery.

The Blood Component Iron Causes Neuronal Apoptosis Following Intracerebral Hemorrhage via the PERK Pathway

PERK signaling pathway plays an important role in neuronal apoptosis after Intracerebral hemorrhage (ICH). ICH can cause the release of blood components into the brain. However, which component in the blood plays a major role still unclear. This study was designed to investigate the activation of the PERK pathway in different blood components after ICH and explore which components have major relationships with neuronal apoptosis. Eighty-five Sprague-Dawley rats were used to establish an ICH model. Western blot (WB) and immunofluorescence (IF) were used to evaluate the expression of the PERK pathway. TUNEL staining, FJC staining and neurological score were used to evaluate neuronal apoptosis and necrosis after ICH. The results showed that protein levels of p-PERK and p-eIF2α were upregulated following ICH with the injection of Fe³⁺ and Fe²⁺ after 48 h. Then, deferoxamine (DFX) was used to study the roles of Fe³⁺ in ICH through the PERK signaling pathway. The results showed that injection of DFX reversed increasing protein levels and prevented neuronal apoptosis. Thus, iron plays an important role in ICH through the PERK signaling pathway. Furthermore, the reduction of iron demonstrates neuroprotective effects in ICH. This suggests that targeting intervention of the iron and PERK pathway could be an effective treatment strategy to improve ICH prognosis.

Hemorrhagic stroke

Hemorrhagic stroke comprises about 20% of all strokes, with intracerebral hemorrhage (ICH) being the most common type. Frequency of ICH is increased where hypertension is untreated. ICH in particularly has a disproportionately high risk of early mortality and long-term disability. Until recently, there has been a paucity of randomized controlled trials (RCTs) to provide evidence for the efficacy of various commonly considered interventions in ICH, including acute blood pressure management, coagulopathy reversal, and surgical hematoma evacuation. Evidence-based guidelines do exist for ICH and these form the basis for a framework of care. Current approaches emphasize control of extremely high blood pressure in the acute phase, rapid reversal of vitamin K antagonists, and surgical evacuation of cerebellar hemorrhage. Lingering questions, many of which are the topic of ongoing clinical research, include optimizing individual blood pressure targets, reversal strategies for newer anticoagulant medications, and the role of minimally invasive surgery. Risk stratification models exist, which derive from findings on clinical exam and neuroimaging, but care should be taken to avoid a self-fulfilling prophecy of poor outcome from limiting treatment due to a presumed poor prognosis. Cerebral venous thrombosis is an additional subtype of hemorrhagic stroke that has a unique set of causes, natural history, and treatment and is discussed as well.

Intracerebral haemorrhage: from clinical settings to animal models

Spontaneous intracerebral haemorrhage (ICH) is a devastating type of stroke with high mortality and morbidity and for which no effective treatments are available to date. Much experimental and clinical research have been performed to explore its mechanisms regard the subsequent inflammatory cascade and to seek the potential therapeutic strategies. The aim of this review is to discuss insights from clinical settings that have led to the development of numerous animal models of ICH. Some of the current and future challenges for clinicians to understand ICH are also surveyed.

Challenges and Opportunities of Deferoxamine Delivery for Treatment of Alzheimer's Disease, Parkinson's Disease, and Intracerebral Hemorrhage

Deferoxamine mesylate (DFO) is an FDA-approved, hexadentate iron chelator routinely used to alleviate systemic iron burden in thalassemia major and sickle cell patients. Iron accumulation in these disease states results from the repeated blood transfusions required to manage these conditions. Iron accumulation has also been implicated in the pathogenesis of Alzheimer's disease (AD), Parkinson's disease (PD), and secondary injury following intracerebral hemorrhage (ICH). Chelation of brain iron is thus a promising therapeutic strategy for improving behavioral outcomes and slowing neurodegeneration in the aforementioned disease states, though the effectiveness of DFO treatment is limited on several accounts. Systemically administered DFO results in nonspecific toxicity at high doses, and the drug's short half-life leads to low patient compliance. Mixed reports of DFO's ability to cross the blood-brain barrier (BBB) also appear in literature. These limitations necessitate novel DFO formulations prior to the drug's widespread use in managing neurodegeneration. Herein, we discuss the various dosing regimens and formulations employed in intranasal (IN) or systemic DFO treatment, as well as the physiological and behavioral outcomes observed in animal models of AD, PD, and ICH. The clinical progress of chelation therapy with DFO in managing neurodegeneration is also evaluated. Finally, the elimination of intranasally administered particles via the glymphatic system and efflux transporters is discussed. Abundant preclinical evidence suggests that intranasal DFO treatment improves memory retention and behavioral outcome in rodent models of AD, PD, and ICH. Several other biochemical and physiological metrics, such as tau phosphorylation, the survival of tyrosine hydroxylase-positive neurons, and infarct volume, are also positively affected by intranasal DFO treatment. However, dosing regimens are inconsistent across studies, and little is known about brain DFO concentration following treatment. Systemic DFO treatment yields similar results, and some complex formulations have been developed to improve permeability across the BBB. However, despite the success in preclinical models, clinical translation is limited with most clinical evidence investigating DFO treatment in ICH patients, where high-dose treatment has proven dangerous and dosing regimens are not consistent across studies. DFO is a strong drug candidate for managing neurodegeneration in the aging population, but before it can be routinely implemented as a therapeutic agent, dosing regimens must be standardized, and brain DFO content following drug administration must be understood and controlled via novel formulations.

Adenoviral transfer of hemopexin gene attenuates oxidative stress and apoptosis in cultured primary cortical neuron cell exposed to blood clot

BACKGROUND

A growing body of experimental evidence suggests that hemin released from heme is a potent oxidant and accumulates in intracranial hematomas. Hemopexin (Hpx) decreases hemin accumulation and catabolism by nerve cells. In previous study, we observed that Hpx gene knockout aggravated striatal injury and worsened behavioral deficits of mice subjected to intracerebral hemorrhage.

AIM

To examine the effect of Hpx on oxidative damage and apoptosis in cultured nerve cells with blood clot.

METHODS

Neuron and glial cells were transfected with adenoviral Hpx gene. Transfected primary neuron-glial cells were co-cultured with 50 μl of arterial blood clot using insert transwells. The sham group was co-coulture with 50 μl of DMEM/F12, which contained 28 μl of serum; the control group was transfected with adenoviral vector. At 12 and 24 h, the level of malonaldehyde (MDA), surperoxide dismutase (SOD) concentration, glutathione (GSH), apoptosis, expression of HO-1 and caspase-3 were detected.

RESULTS

MDA level was decreased (P < 0.01) whereas SOD and GSH concentration were increased in the Hpx group (P < 0.05 and P < 0.01, respectively). Results of flow cytometry revealed no significant difference in apoptosis between the Hpx group and model group at 12 h. However, the percentage of cells undergoing apoptosis in the Hpx group was decreased at 24 h compared with the model group (P < 0.01). HO-1 expression decreased in the Hpx group at 24 h (P < 0.01) while caspase-3 expression decreased at both 12 and 24 h (P < 0.011 and P < 0.05, respectively) compared with the model group.

CONCLUSION

Hpx protected nerve cells exposed to blood from injury by anti-oxidation and a decrease in the expression of HO-1 and caspase-3.

Deferoxamine deconditioning increases neuronal vulnerability to hemoglobin

Concomitant treatment with deferoxamine (DFO) protects neural cells from iron and heme-mediated oxidative injury, but also disrupts cell responses to iron loading that may be protective. We hypothesized that DFO treatment and withdrawal would subsequently increase neuronal vulnerability to hemoglobin. Pretreatment with DFO followed by its washout increased neuronal loss after subsequent hemoglobin exposure by 3-4-fold compared with control vehicle-pretreated cultures. This was associated with reduced ferritin induction by hemoglobin; expression of heme oxygenase-1, which catalyzes iron release from heme, was not altered. Increased neuronal loss was prevented by exogenous apoferritin or by continuing DFO or antioxidants throughout the experimental course. Cell nonheme iron levels after hemoglobin treatment were similar in DFO-pretreated and control cultures. These results indicate that DFO deconditions neurons and subsequently increases their vulnerability to heme-mediated injury. Its net effect after CNS hemorrhage may be highly dependent on the timing and duration of its administration. Withdrawal of DFO while heme or iron levels remain elevated may be deleterious, and may negate any benefit of prior concomitant therapy.

Prx2 (Peroxiredoxin 2) as a Cause of Hydrocephalus After Intraventricular Hemorrhage

Background and Purpose- Our recent study demonstrated that release of Prx2 (peroxiredoxin 2) from red blood cells (RBCs) is involved in the inflammatory response and brain injury after intracerebral hemorrhage. The current study investigated the role of extracellular Prx2 in hydrocephalus development after experimental intraventricular hemorrhage. Methods- There were 4 parts in this study. First, Sprague-Dawley rats received an intraventricular injection of lysed RBC or saline and were euthanized at 1 hour for Prx2 measurements. Second, rats received an intraventricular injection of Prx2, deactivated Prx2, or saline. Third, lysed RBC was coinjected with conoidin A, a Prx2 inhibitor, or vehicle. Fourth, rats received Prx2 injection and were treated with minocycline or saline (i.p.). The effects of Prx2 and the inhibitors were examined using magnetic resonance imaging assessing ventriculomegaly, histology assessing ventricular wall damage, and immunohistochemistry to assess inflammation, particularly at the choroid plexus. Results- Intraventricular injection of lysed RBC resulted in increased brain Prx2 and hydrocephalus. Intraventricular injection of Prx2 alone caused hydrocephalus, ventricular wall damage, activation of choroid plexus epiplexus cells (macrophages), and an accumulation of neutrophils. Conoidin A attenuated lysed RBC-induced injury. Systemic minocycline treatment reduced the epiplexus cell activation and hydrocephalus induced by Prx2. Conclusions- Prx2 contributed to the intraventricular hemorrhage-induced hydrocephalus, probably by inducing inflammatory responses in choroid plexus and ventricular wall damage.

Intracerebral Hemorrhage-Induced Brain Injury in Rats: the Role of Extracellular Peroxiredoxin 2

Red blood cell (RBC) lysis within the hematoma causes brain injury following intracerebral hemorrhage. Peroxiredoxin 2 (PRX-2) is the third most abundant protein in RBCs and this study examined the potential role of PRX-2 in inducing brain injury in rats. First, adult male Sprague-Dawley rats had an intracaudate injection of lysed RBCs or saline. Brains were harvested at 1 h to measure PRX-2 levels. Second, rats had an intracaudate injection of either recombinant PRX-2, heat-inactivated PRX-2, or saline. Third, rats had intracaudate co-injection of lysed RBCs with conoidin A, a PRX-2 inhibitor, or vehicle. For the second and third parts of studies, behavioral tests were performed and all rats had magnetic resonance imaging prior to euthanasia for brain immunohistochemistry and Western blotting. We found that brain PRX-2 levels were increased after lysed RBC injection. Intracaudate injection of PRX-2 resulted in blood-brain barrier disruption, brain swelling, neutrophil infiltration, microglia activation, neuronal death, and neurological deficits. Intracerebral injection of lysed RBCs induced brain injury, which was reduced by conoidin A. These results suggest that extracellular PRX-2 released from hematoma can cause brain injury following brain hemorrhage and could be a potential therapeutic target.

Haptoglobin genotype and outcome after spontaneous intracerebral haemorrhage

OBJECTIVE

Haptoglobin is a haemoglobin-scavenging protein that binds and neutralises free haemoglobin and modulates inflammation and endothelial progenitor cell function. A HP gene copy number variation (CNV) generates HP1 and HP2 alleles, while the single-nucleotide polymorphism rs2000999 influences their levels. The HP1 allele is hypothesised to improve outcome after spontaneous (non-traumatic) intracerebral haemorrhage (ICH). We investigated the associations of the HP CNV genotype and rs2000999 with haematoma volume, perihaematomal oedema (PHO) volume, functional outcome and mortality after ICH.

METHODS

We included patients with neuroimaging-proven ICH, available DNA and 6-month follow-up in an observational cohort study (CROMIS-2). We classified patients into three groups according to the HP CNV: 1-1, 2-1 or 2-2 and also dichotomised HP into HP1-containing genotypes (HP1-1 and HP2-1) and HP2-2 to evaluate the HP1 allele. We measured ICH and PHO volume on CT; PHO was measured by oedema extension distance. Functional outcome was assessed by modified Rankin score (unfavourable outcome defined as mRS 3-6).

RESULTS

We included 731 patients (mean age 73.4, 43.5% female). Distribution of HP CNV genotype was: HP1-1 n=132 (18.1%); HP2-1 n=342 (46.8%); and HP2-2 n=257 (35.2%). In the multivariable model mortality comparisons between HP groups, HP2-2 as reference, were as follows: OR HP1-1 0.73, 95% CI 0.34 to 1.56 (p value=0.41) and OR HP2-1 0.5, 95% CI 0.28 to 0.89 (p value=0.02) (overall p value=0.06). We found no evidence of association of HP CNV or rs200999 with functional outcome, ICH volume or PHO volume.

CONCLUSION

The HP2-1 genotype might be associated with lower 6-month mortality after ICH; this finding merits further study.

Histotripsy Clot Liquefaction in a Porcine Intracerebral Hemorrhage Model

BACKGROUND

Intracerebral hemorrhage (ICH) is characterized by a 30-d mortality rate of 40% and significant disability for those who survive.

OBJECTIVE

To investigate the initial safety concerns of histotripsy mediated clot liquefaction and aspiration in a porcine ICH model. Histotripsy is a noninvasive, focused ultrasound technique that generates cavitation to mechanically fractionate tissue. Histotripsy has the potential to liquefy clot in the brain and facilitate minimally invasive aspiration.

METHODS

About 1.75-mL clots were formed in the frontal lobe of the brain (n = 18; n = 6/group). The centers of the clots were liquefied with histotripsy 48 h after formation, and the content was either evacuated or left within the brain. A control group was left untreated. Pigs underwent magnetic resonance imaging (MRI) 7 to 8 d after clot formation and were subsequently euthanized. Neurological behavior was assessed throughout. Histological analysis was performed on harvested brains. A subset of pigs underwent acute analysis (≤6 h).

RESULTS

Histotripsy was able to liquefy the center of clots without direct damage to the perihematomal brain tissue. An average volume of 0.9 ± 0.5 mL was drained after histotripsy treatment. All groups showed mild ischemia and gliosis in the perihematomal region; however, there were no deaths or signs of neurological dysfunction in any groups.

CONCLUSION

This study presents the first analysis of histotripsy-based liquefaction of ICH in vivo. Histotripsy safely liquefies clots without significant additional damage to the perihematomal region. The liquefied content of the clot can be easily evacuated, and the undrained clot has no effect on pig survival or neurological behavior.

Regulation of AQP4 in the Central Nervous System

Aquaporin-4 (AQP4) is the main water channel protein expressed in the central nervous system (CNS). AQP4 is densely expressed in astrocyte end-feet, and is an important factor in CNS water and potassium homeostasis. Changes in AQP4 activity and expression have been implicated in several CNS disorders, including (but not limited to) epilepsy, edema, stroke, and glioblastoma. For this reason, many studies have been done to understand the various ways in which AQP4 is regulated endogenously, and could be regulated pharmaceutically. In particular, four regulatory methods have been thoroughly studied; regulation of gene expression via microRNAs, regulation of AQP4 channel gating/trafficking via phosphorylation, regulation of water permeability using heavy metal ions, and regulation of water permeability using small molecule inhibitors. A major challenge when studying AQP4 regulation is inter-method variability. A compound or phosphorylation which shows an inhibitory effect in vitro may show no effect in a different in vitro method, or even show an increase in AQP4 expression in vivo. Although a large amount of variability exists between in vitro methods, some microRNAs, heavy metal ions, and two small molecule inhibitors, acetazolamide and TGN-020, have shown promise in the field of AQP4 regulation.

Fully Automated Segmentation Algorithm for Perihematomal Edema Volumetry After Spontaneous Intracerebral Hemorrhage

Background and Purpose- Perihematomal edema (PHE) is a promising surrogate marker of secondary brain injury in patients with spontaneous intracerebral hemorrhage, but it can be challenging to accurately and rapidly quantify. The aims of this study are to derive and internally validate a fully automated segmentation algorithm for volumetric analysis of PHE. Methods- Inpatient computed tomography scans of 400 consecutive adults with spontaneous, supratentorial intracerebral hemorrhage enrolled in the Intracerebral Hemorrhage Outcomes Project (2009-2018) were separated into training (n=360) and test (n=40) datasets. A fully automated segmentation algorithm was derived from manual segmentations in the training dataset using convolutional neural networks, and its performance was compared with that of manual and semiautomated segmentation methods in the test dataset. Results- The mean volumetric dice similarity coefficients for the fully automated segmentation algorithm were 0.838±0.294 and 0.843±0.293 with manual and semiautomated segmentation methods as reference standards, respectively. PHE volumes derived from the fully automated versus manual (r=0.959; P<0.0001), fully automated versus semiautomated (r=0.960; P<0.0001), and semiautomated versus manual (r=0.961; P<0.0001) segmentation methods had strong between-group correlations. The fully automated segmentation algorithm (mean 18.0±1.8 seconds/scan) quantified PHE volumes at a significantly faster rate than both of the manual (mean 316.4±168.8 seconds/scan; P<0.0001) and semiautomated (mean 480.5±295.3 seconds/scan; P<0.0001) segmentation methods. Conclusions- The fully automated segmentation algorithm accurately quantified PHE volumes from computed tomography scans of supratentorial intracerebral hemorrhage patients with high fidelity and greater efficiency compared with manual and semiautomated segmentation methods. External validation of fully automated segmentation for assessment of PHE is warranted.

Gadolinium causes M1 and M2 microglial apoptosis after intracerebral haemorrhage and exerts acute neuroprotective effects

OBJECTIVES

Gadolinium (Gd) affects microglial polarization during remyelination. We previously reported that the suppression of proinflammatory microglia was neuroprotective in intracerebral haemorrhage (ICH). The objective of the present study was to investigate the effects of Gd on microglial polarization and neuronal injury after ICH.

METHODS

Gadolinium was intraperitoneally administered to ICH mice prepared by an intrastriatal microinjection of collagenase type VII. The polarization of M1, 2a, b and c microglia was evaluated by real-time PCR using the respective markers. Changes in representative mRNAs were also confirmed by immunological methods. Neuroprotective effects were evaluated by counting NeuN-positive cells and a behavioural analysis.

KEY FINDINGS

One day after ICH, the mRNA levels of proinflammatory M1 microglial markers, such as inducible nitric oxide synthase (iNOS), and anti-inflammatory M2 microglial markers, such as arginase1 (M2a, c), Ym1 (M2a), and transforming growth factor-β (M2c), increased, while those of chemokine CCL1 (M2b) only increased after 3 days. Gd decreased the levels of all M1 and M2 markers. Arginase1 and iNOS protein levels also increased, and Gd reduced them due to apoptotic cell death. Gadolinium attenuated oedema, neuron loss, neurological deficits and the mortality rate without affecting haematoma sizes.

CONCLUSIONS

Gadolinium induced M1 and M2 microglial apoptosis and exerted acute neuroprotective effects after ICH.

Echinocystic acid provides a neuroprotective effect via the PI3K/AKT pathway in intracerebral haemorrhage mice

Background

Echinocystic acid (EA), a natural extract from plants of Gleditsia sinensis Lam, exhibits anti-inflammatory, antioxidant and analgesic activities in different diseases. In this study, we explored the pharmacological effects of EA on intracerebral haemorrhage (ICH) in a collagenase-induced ICH mouse model.

Methods

EA (50 mg/kg, i.p. q.d) was injected after the establishment of ICH, and we measured the amount of degraded neurons in brain tissue with Fluoro-Jade C staining and the haemorrhagic injury volume with Luxol fast blue staining on day 3 after ICH. We also assessed animal behaviour by rotarod test, claw force test and modified neurological severity score (mNSS) score. The expression of apoptosis-related proteins such as Bcl-2, Bax and cleaved caspase-3 was analysed by Western blot.

Results

EA reduced both the death of neurons and the volume of haemorrhagic injury after ICH. The haemorrhage infarct volume of the ICH+EA group was 9.84%±3.32% lower than that in the ICH group of mice (P<0.01). The mNSS score of the ICH+EA treated group was 4.75±0.55 lower than that in the ICH group (P<0.01). With the administration of EA after ICH, the expression of Bcl-2 was upregulated while the Bax level was downregulated. The cleaved caspase-3 level was also significantly decreased. We further investigated the neuroprotective mechanism of EA. Western blot results showed that the expression of P-AKT increased after EA treatment and decreased after LY294002, an inhibitor of the PI3K/AKT pathway, treatment.

Conclusions

EA may provide neuroprotection via activation of the PI3K/AKT pathway. Given the safety of EA has been proven, further studies are required to investigate whether EA is a potential agent for the treatment of ICH.

Over-Activated Proteasome Mediates Neuroinflammation on Acute Intracerebral Hemorrhage in Rats

Background: Neuroinflammation is a hallmark in intracerebral hemorrhage (ICH) that induces secondary brain injury, leading to neuronal cell death. ER stress-triggered apoptosis and proteostasis disruption caused neuroinflammation to play an important role in various neurological disorders. The consequences of ER stress and proteostasis disruption have rarely been studied during the course of ICH development. Methods: ICH was induced by collagenase VII-S intrastriatal infusion. Animals were sacrificed at 0, 3, 6, 24, and 72 h post-ICH. Rats were determined for body weight changes, hematoma volume, and neurological deficits. Brain tissues were harvested for molecular signaling analysis either for ELISA, immunoblotting, immunoprecipitation, RT-qPCR, protein aggregation, or for histological examination. A non-selective proteasome inhibitor, MG132, was administered into the right striatum three hours prior to ICH induction. Results: ICH-induced acute proteasome over-activation caused the early degradation of the endoplasmic reticulum (ER) chaperone GRP78 and IκB protein. These exacerbations were accompanied by the elevation of pro-apoptotic CCAAT-enhancer-binding protein homologous protein (CHOP) and pro-inflammatory cytokines expression via nuclear factor-kappa B (NF-κB) signal activation. Pre-treatment with proteasome inhibitor MG132 significantly ameliorated the ICH-induced ER stress/proteostasis disruption, pro-inflammatory cytokines, neuronal cells apoptosis, and neurological deficits. Conclusions: ICH induced rapid proteasome over-activation, leading to an exaggeration of the ER stress/proteostasis disruption, and neuroinflammation might be a critical event in acute ICH pathology.

Minimally invasive surgery and transsulcal parafascicular approach in the evacuation of intracerebral haemorrhage

Intracerebral haemorrhage (ICH) describes haemorrhage into the brain parenchyma that may result in a decline of the patient’s neurological function. ICH is a common cause of morbidity and mortality worldwide. Aggressive surgical treatment for ICH has remained controversial as clinical trials have failed to demonstrate substantial improvement in patient outcome and mortality. Recently, promising mechanical and pharmacological minimally invasive surgery (MIS) techniques for the treatment of ICH have been described. MIS was designed with the objective of reducing morbidity due to complications of surgical manipulation. Mechanical MIS includes the use of tubular retractors and small diameter instruments for ICH removal. Pharmacological methods consist of catheter placement inside the haematoma cavity for the passive drainage of the haematoma over the course of several days. One of the most favourable approaches for MIS is the use of natural corridors for reaching the lesion, such as the transsulcal parafascicular approach. This approach provides an anatomical dissection of the subjacent white matter tracts, causing the least amount of damage while evacuating the haematoma. A detailed description of the currently known MIS techniques and devices is presented in this review. Special attention is given to the transsulcal parafascicular approach, which has particular benefits to provide a less traumatic MIS with promising overall patient outcome.

Increased perihematomal neuron autophagy and plasma thrombin-antithrombin levels in patients with intracerebral hemorrhage: An observational study

Animal studies have demonstrated that autophagy was involved in neuronal damage after intracerebral hemorrhage (ICH). Several studies showed thrombin-antithrombin (TAT) plasma levels were elevated in patients with ICH. In this study, we aimed to evaluate if autophagy occurred in patients with ICH; and the relationship between the severity of brain injury and plasma TAT levels.A novel tissue harvesting device was used during hematoma removal surgery to collect loose fragments of tissue surrounding the affected brain area in 27 ICH patients with hematoma volumes of >30 mL in the basal ganglia. Control tissues were obtained from patients who underwent surgery for arteriovenous malformation (n = 25). Transmission electron microscopy (TEM) and immunohistochemistry for autophagy-related proteins were used to evaluate the ultrastructural and morphologic cellular characteristics; and the extent of autophagy in the recovered tissue specimens. Stroke severity was assessed by using the Glasgow Coma Scale (GCS) and the National Institutes of Health Stroke Scale (NIHSS). An enzyme-linked immunosorbent assay (ELISA) was used to measure plasma TAT levels.Transmission electron microscopy showed autophagosomes and autolysosomes exist in neurons surrounding the hematoma, but not in the control tissues. The number of cells containing autophagic vacuoles correlated with the severity of brain injury. Immunohistochemistry showed strong LC3, beclin 1, and cathepsin D staining in ICH tissue specimens. Plasma TAT levels correlated positively with autophagic cells and ICH severity (P < .01).Autophagy was induced in perihematomal neurons after ICH. Autophagy and plasma TAT levels correlated positively with severity of brain injury. These results suggest that autophagy and increased plasma TAT levels may contribute to the secondary damage in ICH patients.

Changes in the Lectin Pathway Following Intracerebral or Spontaneous Subarachnoid Hemorrhage

Previous research indicates that the complement system is activated after occurrence of intracerebral hemorrhage (ICH) and spontaneous subarachnoid hemorrhage (SAH). The role of the lectin pathway (LP) of the complement system in this activation has only scarcely been investigated. The aim of this study was to determine the plasma concentration of the LP proteins in patients with ICH or SAH at admission compared to healthy individuals. Secondly, ICH and SAH patients were followed during the initial 24 h of disease, to investigate changes in LP protein concentrations during the critical acute phase. This prospective, observational study included 30 ICH and 33 SAH patients. EDTA plasma samples were collected at admission, 6 and 24 h after symptom onset. Time-resolved immuno-flourometric assays (TRIFMA) were used to measure all proteins of the LP in patient samples and in samples from age- and gender-matched healthy individuals. Compared to healthy individuals, ICH and SAH patients had increased levels of H-ficolin (p = 0.04, p = 0.03), M-ficolin (both p < 0.0001), and MAp44 (both p = 0.01) at admission. M-ficolin, H-ficolin, CL-L1, MASP-1, MASP-3, and MAp44 decreased significantly in both ICH and SAH patients during the initial 24 h after symptom onset. In conclusion, we observed significant differences in lectin pathway protein concentrations between patients with ICH or SAH and healthy individuals. Significant dynamics in lectin pathway protein levels were demonstrated during the initial 24 h after symptom onset. This indicates a potential role of the LP proteins during the acute phase of SAH and ICH.

Neural Injuries Induced by Hydrostatic Pressure Associated With Mass Effect after Intracerebral Hemorrhage

Mass effect induced by growing hematoma is one of the mechanisms by which intracerebral hemorrhage (ICH) may result in brain injuries. Our goal was to investigate the damage mechanism of hydrostatic pressure associated with mass effect and the cooperative effect of hydrostatic pressure plus hemoglobin on neural injuries. Loading hydrostatic pressure on neurons and injecting agarose gel in the right striatum of rats was performed to establish the in vitro and vivo ICH models, respectively. The elevated hydrostatic pressure associated with ICH suppressed neurons and neural tissues viability, and disturbed the axons and dendrites in vitro and vivo. Moreover, hydrostatic pressure could upregulate the expression of cleaved-caspase-3 and BAX, and downregulate Bcl-2 and Bcl-xL. Meanwhile, the toxicity of hemoglobin would be enhanced when conducted with hydrostatic pressure together. Furthermore, the exclusive hydrostatic pressure could upregulate the Piezo-2 expression, which reached a plateau at 8 h after ICH. And hemoglobin increased Piezo-2 expression significantly in vivo, and that was also promoted significantly by the elevated volume of Gel in the cooperative groups. Results indicated that hydrostatic pressure induced by mass effect not only gave rise to brain injuries directly, but also increased the toxicity of hemoglobin in the progress of secondary brain injury after ICH.