Lobar intracerebral hemorrhage model in pigs: rapid edema development in perihematomal white matter

Optimization of Catheter Based rtPA Thrombolysis in a Novel In Vitro Clot Model for Intracerebral Hemorrhage

Hematoma lysis with recombinant tissue plasminogen activator (rtPA) has emerged as an alternative therapy for spontaneous intracerebral hemorrhage (ICH). Optimal dose and schedule are still unclear. The aim of this study was to create a reliable in vitro blood clot model for investigation of optimal drug dose and timing. An in vitro clot model was established, using 25 mL and 50 mL of human blood. Catheters were placed into the clots and three groups, using intraclot application of rtPA, placebo, and catheter alone, were analyzed. Dose-response relationship, repetition, and duration of rtPA treatment and its effectiveness in aged clots were investigated. A significant relative end weight difference was found in rtPA treated clots compared to catheter alone (p = 0.002) and placebo treated clots (p < 0.001). Dose-response analysis revealed 95% effective dose around 1 mg rtPA in 25 and 50 mL clots. Approximately 80% of relative clot lysis could be achieved after 15 min incubation. Lysis of aged clots was less effective. A new clot model for in vitro investigation was established. Our data suggest that current protocols for rtPA based ICH therapy may be optimized by using less rtPA at shorter incubation times.

Intracerebral Hemorrhage: Perihemorrhagic Edema and Secondary Hematoma Expansion: From Bench Work to Ongoing Controversies

Intracerebral hemorrhage (ICH) is a medical emergency, which often leads to severe disability and death. ICH-related poor outcomes are due to primary injury causing structural damage and mass effect and secondary injury in the perihemorrhagic region over several days to weeks. Secondary injury after ICH can be due to hematoma expansion (HE) or a consequence of repair pathway along the continuum of neuroinflammation, neuronal death, and perihemorrhagic edema (PHE). This review article is focused on PHE and HE and will cover the animal studies, related human studies, and clinical trials relating to these mechanisms of secondary brain injury in ICH patients.

Targeting Secondary Hematoma Expansion in Spontaneous Intracerebral Hemorrhage - State of the Art

Spontaneous intracerebral hemorrhage (SICH), defined broadly as intracerebral hemorrhage not related to trauma, results in long-term disability or death in a large proportion of afflicted patients. Current management of this disease is predominantly supportive, including airway protection, optimization of hemodynamic parameters, and management of intracranial pressure. No active treatments that demonstrate beneficial effects on clinical outcome are currently available. Animal models of SICH have allowed for the elucidation of multiple pathways that may be attractive therapeutic targets. A minority of these, such as aggressive blood pressure management and recombinant activated factor VII administration, have led to large-scale clinical trials. There remains a critical need for further translational research in the realm of SICH.

Treatment Strategies to Attenuate Perihematomal Edema in Patients With Intracerebral Hemorrhage

Spontaneous intracerebral hemorrhage (SICH) continues to be a significant cause of neurologic morbidity and mortality throughout the world. Although recent advances in the treatment of SICH have significantly decreased mortality rates, functional recovery has not been dramatically improved by any intervention to date. There are 2 predominant mechanisms of brain injury from intracerebral hemorrhage: mechanical injury from the primary hematoma (including growth of that hematoma), and secondary injury from perihematomal inflammation. For instance, in the hours to weeks after SICH as the hematoma is being degraded, thrombin and iron are released and can result in neurotoxicity, free radical damage, dysregulated coagulation, and harmful inflammatory cascades; this can clinically and radiologically manifest as perihematomal edema (PHE). PHE can contribute to mass effect, cause acute neurologic deterioration in patients, and has even been associated with poor long-term functional outcomes. PHE therefore lends itself to being a potential therapeutic target. In this article, we will review 1) the pathogenesis and time course of the development of PHE, and 2) the clinical series and trials exploring various methods, with a focus on minimally invasive surgical techniques, to reduce PHE and minimize secondary brain injury. Promising areas of continued research also will be discussed.

Hematoma Changes During Clot Resolution After Experimental Intracerebral Hemorrhage

BACKGROUND AND PURPOSE

Hematoma clearance occurs in the days after intracerebral hemorrhage (ICH) and has not been well studied. In the current study, we examined changes in the hematoma in a piglet ICH model. The effect of deferoxamine on hematoma was also examined.

METHODS

The ICH model was induced by an injection of autologous blood into the right frontal lobe of piglets. First, a natural time course of hematoma changes ≤7 days was determined. Second, the effect of deferoxamine on hematoma changes was examined. Hemoglobin and membrane attack complex levels in the hematoma were examined by enzyme-linked immunosorbent assay. Immunohistochemistry and Western blotting were used to examine CD47 (a regulator of erythrophagocytosis), CD163 (a hemoglobin scavenger receptor), and heme oxygenase-1 (a heme degradation enzyme) in the clot.

RESULTS

After ICH, there was a reduction in red blood cell diameter within the clot with time. This was accompanied by membrane attack complex accumulation and decreased hemoglobin levels. Erythrophagocytosis occurred in the hematoma, and this was associated with reduced clot CD47 levels. Activated macrophages/microglia were CD163 and hemeoxygenase-1 positive, and these accumulated in the clot with time. Deferoxamine treatment attenuated the process of hematoma resolution by reducing member attack complex formation and inhibiting CD47 loss in the clot.

CONCLUSIONS

These results indicate that membrane attack complex and erythrophagocytosis contribute to hematoma clearance after ICH, which can be altered by deferoxamine treatment.

Molecular pathophysiology of cerebral edema

Advancements in molecular biology have led to a greater understanding of the individual proteins responsible for generating cerebral edema. In large part, the study of cerebral edema is the study of maladaptive ion transport. Following acute CNS injury, cells of the neurovascular unit, particularly brain endothelial cells and astrocytes, undergo a program of pre- and post-transcriptional changes in the activity of ion channels and transporters. These changes can result in maladaptive ion transport and the generation of abnormal osmotic forces that, ultimately, manifest as cerebral edema. This review discusses past models and current knowledge regarding the molecular and cellular pathophysiology of cerebral edema.

Effect of Decompressive Craniectomy on Perihematomal Edema in Patients with Intracerebral Hemorrhage

Background

Perihematomal edema contributes to secondary brain injury in the course of intracerebral hemorrhage. The effect of decompressive surgery on perihematomal edema after intracerebral hemorrhage is unknown. This study analyzed the course of PHE in patients who were or were not treated with decompressive craniectomy.

Methods

More than 100 computed tomography images from our published cohort of 25 patients were evaluated retrospectively at two university hospitals in Switzerland. Computed tomography scans covered the time from admission until day 100. Eleven patients were treated by decompressive craniectomy and 14 were treated conservatively. Absolute edema and hematoma volumes were assessed using 3-dimensional volumetric measurements. Relative edema volumes were calculated based on maximal hematoma volume.

Results

Absolute perihematomal edema increased from 42.9 ml to 125.6 ml (192.8%) after 21 days in the decompressive craniectomy group, versus 50.4 ml to 67.2 ml (33.3%) in the control group (Δ at day 21 = 58.4 ml, p = 0.031). Peak edema developed on days 25 and 35 in patients with decompressive craniectomy and controls respectively, and it took about 60 days for the edema to decline to baseline in both groups. Eight patients (73%) in the decompressive craniectomy group and 6 patients (43%) in the control group had a good outcome (modified Rankin Scale score 0 to 4) at 6 months (P = 0.23).

Conclusions

Decompressive craniectomy is associated with a significant increase in perihematomal edema compared to patients who have been treated conservatively. Perihematomal edema itself lasts about 60 days if it is not treated, but decompressive craniectomy ameliorates the mass effect exerted by the intracerebral hemorrhage plus the perihematomal edema, as reflected by the reduced midline shift.

Post-Injury Administration of Tert-butylhydroquinone Attenuates Acute Neurological Injury After Intracerebral Hemorrhage in Mice

Intracerebral hemorrhage (ICH) is a severe form of stroke with substantial public health impact. Notably, there is no effective treatment for ICH. Given the role of transcription factor Nrf2 (NF-E2-related factor 2) in antioxidant signaling, herein, we tested the efficacy of tert-butylhydroquinone (TBHQ), a selective inducer of Nrf2 in a preclinical model of ICH. Male CD1 mice were subjected to experimental intracerebral hemorrhage and administered intraperitoneally with TBHQ. The administration of TBHQ enhanced the DNA-binding activity of Nrf2 in the brain and reduced oxidative brain damage in comparison to vehicle-treated ICH. In addition, TBHQ treatment reduced microglial activation with concomitant reduction in the release of proinflammatory cytokine interleukin-1β (IL-1 β). Furthermore, TBHQ treatment attenuated neurodegeneration and improved neurological outcomes after ICH. Altogether, the data demonstrate the efficacy of post-injury administration of TBHQ in attenuating acute neurological injury after ICH.

Brain Volume Determination in Subarachnoid Hemorrhage Using Rats

Brain edema is routinely measured using the wet-dry method. Volume, however, is the sum total of all cerebral tissues, including water. Therefore, volumetric change following injury may not be adequately quantified using percentage of edema. We thus tested the hypothesis that dried brains can be reconstituted with water and then re-measured to determine the actual volume. Subarachnoid hemorrhage (SAH) was induced by endovascular perforation in adult male Sprague-Dawley rats (n = 30). Animals were euthanized at 24 and 72 h after evaluation of neurobehavior for determination of brain water content. Dried brains were thereafter reconstituted with equal parts of water (lost from brain edema) and centrifuged to remove air bubbles. The total volume was quantified using hydrostatic (underwater) physics principles that 1 ml water (mass) = 1 cm(3) (volume). The amount of additional water needed to reach a preset level marked on 2-ml test tubes was added to that lost from brain edema, and from the brain itself, to determine the final volume. SAH significantly increased both brain water and volume while worsening neurological function in affected rats. Volumetric measurements demonstrated significant brain swelling after SAH, in addition to the brain edema approach. This modification of the "wet-dry" method permits brain volume determination using valuable post hoc dried brain tissue.

The Histone Deacetylase Inhibitor Suberoylanilide Hydroxamic Acid (SAHA) Confers Acute Neuroprotection After Intracerebral Hemorrhage in Mice

Spontaneous intracerebral hemorrhage (ICH) is a stroke subtype with no effective treatment. Though ICH is known to induce severe neurological damage, the molecular mechanisms of neurological injury after ICH remain largely unclear. Given the emerging role of epigenetic mechanisms in neurodegeneration, the present study evaluated whether suberoylanilide hydroxamic acid (SAHA: vorinostat), a clinically well-tolerated pan-histone deacetylase inhibitor (HDACi), would attenuate neurological injury and improve functional outcomes in a preclinical model of ICH. Mice were administered with SAHA or vehicle after an induction of ICH and acute neuronal death, glial activation, and neurological outcomes were assessed. SAHA-treated mice exhibited less neurodegeneration with concomitant improvement in neurological outcomes than vehicle-treated mice. Furthermore, SAHA downregulated glial activation and the expression of heme oxygenase-1, a stress-inducible enzyme that plays critical roles in neurological damage after ICH. Altogether, the data strongly suggest the role of epigenetic mechanisms in inducing neurological injury after ICH and raise the possible clinical utility of SAHA for therapeutic intervention after ICH.

Neuronal tumour necrosis factor-α and interleukin-1β expression in a porcine model of intracerebral haemorrhage: Modulation by U-74389G

Tumour necrosis factor α (TNF-α) and interleukin 1β (IL-1β) are important mediators of intracerebral haemorrhage (ICH) inflammatory response. Lazaroids, established antioxidants and neuroprotectants, have been studied in several brain pathologies. The present study was designed to investigate: a) TNF-α and IL-1β changes, in neurons and b) U-74389G effects, 4 and 24h after haematoma induction in a porcine model of intracerebral haemorrhage. In twenty male landrace pigs (swines) aged 135-150 days old, autologous whole blood was injected around the right basal ganglia territory; in ten of the pigs the lazaroid compound U-74389G was administered. Brain TNF-α and IL-1β immunopositive neurons were determined by immunoarray techniques at 4 and 24h timepoints. After the haematoma induction the number of TNF-α immunopositive neurons ipsilateral to the haematoma was significantly higher compared to the contralateral site at 4h (p<0.0005), while U-74389G significantly reduced the number of TNF-α immunopositive neurons, ipsilateral to the haematoma, at 4h (p=0.002); at 24h, TNF-α immunopositive neurons were found significantly lower in the control group ipsilateral to the haematoma in comparison to 4h timepoint(p<0.0005). The number of IL-1β immunopositive neurons at 4h after the hematoma induction was significantly higher ipsilateral to the haematoma site (p<0.0005). U-74389G had no statistical significant effect. TNF-α and IL-1β, increase in neurons, 4h after the haematoma induction, ipsilateral to the haematoma site. The administration of the antioxidant compound U-74389G, results in early (at 4h) decrease of TNF-α immunopositive neurons but shows no statistical significant effect to IL-1β immunopossitive neurons.

Targeting secondary injury in intracerebral haemorrhage--perihaematomal oedema

Perihaematomal oedema (PHO) is an important pathophysiological marker of secondary injury in intracerebral haemorrhage (ICH). In this Review, we describe a novel method to conceptualize PHO formation within the framework of Starling's principle of movement of fluid across a capillary wall. We consider progression of PHO through three stages, characterized by ionic oedema (stage 1) and progressive vasogenic oedema (stages 2 and 3). In this context, possible modifiers of PHO volume and their value in identifying patients who would benefit from therapies that target secondary injury are discussed; the practicalities of using neuroimaging to measure PHO volume are also considered. We examine whether PHO can be used as a predictor of neurological outcome following ICH, and we provide an overview of emerging therapies. Our discussion emphasizes that PHO has clinical relevance both as a therapeutic target, owing to its augmentation of the mass effect of a haemorrhage, and as a surrogate marker for novel interventions that target secondary injury.

Increased brain volume among good grade patients with intracerebral hemorrhage. Results from the Antihypertensive Treatment of Acute Cerebral Hemorrhage (ATACH) study

BACKGROUND

We ascertained the occurrence of global cerebral edema manifesting as increased brain volume in subjects with intracerebral hemorrhage (ICH) and explored the relationship between subject characteristics and three month outcomes.

METHODS

A post-hoc analysis of a multicenter prospective study that recruited patients with ICH, elevated SBP ≥170 mm Hg, and Glasgow Coma Scale (GCS) score ≥8, who presented within 6 h of symptom onset was performed. Computed tomographic (CT) scans at baseline and 24 h, submitted to a core image laboratory, were analyzed to measure total brain, hematoma, and perihematoma edema volumes from baseline and 24-h CT scans using image analysis software. The increased brain volume was determined by subtracting the hematoma and perihematomal edema volumes from the total brain volume.

RESULTS

A total of 18 (44 %) of 41 subjects had increased brain volume that developed between initial CT scan and 24-h CT scan. The median increase in brain volume among the 18 subjects was 35 cc ranging from 0.12 to 296 cc. The median baseline GCS score was 15 in both groups of subjects who experienced increased brain volume and those who did not, and the median hematoma volume was 10.18 and 6.73, respectively. Three of the 18 subjects with increased brain volume underwent concurrent neurological deterioration and one subject died during hospitalization.

CONCLUSIONS

We found preliminary evidence of increased cerebral brain volume in subjects with good grade and small ICHs, which may be suggestive of global cerebral edema.

Application of computed tomography for differential diagnosis of glioma stoke and simple cerebral hemorrhage

OBJECTIVE

To explore the value of computed tomography (CT) in the differential diagnosis of glioma stroke and simple cerebral hemorrhage.

MATERIALS AND METHODS

A total of 45 patients with glioma stroke and stroke as the initial symptom in our hospital from Jun., 2009 to Oct., 2013 were selected along with 50 individuals with simple cerebral hemorrhage in the same period randomly collected as a control group. The CT results in both groups were analyzed and compared.

RESULTS

In the observation group, there were 25 patients with astrocytoma (55.6%), 11 with oligodendroglioma (24.4%), 8 with ependymoma (17.2%) and 1 with glioblastoma multiforma (GBM, 2.22%). Additionally, the major CT manifestation was coexistence of hemorrhage and tumor signs. By comparison, it could be found that the proportions of patients respectively with peripheral edema and space- occupying effect in the observation group were significantly higher than in the control group (P<0.01).

CONCLUSIONS

Application of CT examination combined with medical history in patients has very important clinical value in the differential diagnosis of glioma stroke and simple cerebral hemorrhage.

Neuroinflammation after intracerebral hemorrhage

Spontaneous intracerebral hemorrhage (ICH) is a particularly severe type of stroke for which no specific treatment has been established yet. Although preclinical models of ICH have substantial methodological limitations, important insight into the pathophysiology has been gained. Mounting evidence suggests an important contribution of inflammatory mechanisms to brain damage and potential repair. Neuroinflammation evoked by intracerebral blood involves the activation of resident microglia, the infiltration of systemic immune cells and the production of cytokines, chemokines, extracellular proteases and reactive oxygen species (ROS). Previous studies focused on innate immunity including microglia, monocytes and granulocytes. More recently, the role of adaptive immune cells has received increasing attention. Little is currently known about the interactions among different immune cell populations in the setting of ICH. Nevertheless, immunomodulatory strategies are already being explored in ICH. To improve the chances of translation from preclinical models to patients, a better characterization of the neuroinflammation in patients is desirable.

Progressing haemorrhagic stroke: categories, causes, mechanisms and managements

Haemorrhagic stroke is a severe stroke subtype with high rates of morbidity and mortality. Although this condition has been recognised for a long time, the progressing haemorrhagic stroke has not received adequate attention, and it accounts for an even worse clinical outcome than the nonprogressing types of haemorrhagic stroke. In this review article, we categorised the progressing haemorrhagic stroke into acute progressing haemorrhagic stroke, subacute haemorrhagic stroke, and chronic progressing haemorrhagic stroke. Haematoma expansion, intraventricular haemorrhage, perihaematomal oedema, and inflammation, can all cause an acute progression of haemorrhagic stroke. Specific 'second peak' of perihaematomal oedema after intracerebral haemorrhage and 'tension haematoma' are the primary causes of subacute progression. For the chronic progressing haemorrhagic stroke, the occult vascular malformations, trauma, or radiologic brain surgeries can all cause a slowly expanding encapsulated haematoma. The mechanisms to each type of progressing haemorrhagic stroke is different, and the management of these three subtypes differs according to their causes and mechanisms. Conservative treatments are primarily considered in the acute progressing haemorrhagic stroke, whereas surgery is considered in the remaining two types.

Vascular disruption and blood-brain barrier dysfunction in intracerebral hemorrhage

This article reviews current knowledge of the mechanisms underlying the initial hemorrhage and secondary blood-brain barrier (BBB) dysfunction in primary spontaneous intracerebral hemorrhage (ICH) in adults. Multiple etiologies are associated with ICH, for example, hypertension, Alzheimer's disease, vascular malformations and coagulopathies (genetic or drug-induced). After the initial bleed, there can be continued bleeding over the first 24 hours, so-called hematoma expansion, which is associated with adverse outcomes. A number of clinical trials are focused on trying to limit such expansion. Significant progress has been made on the causes of BBB dysfunction after ICH at the molecular and cell signaling level. Blood components (e.g. thrombin, hemoglobin, iron) and the inflammatory response to those components play a large role in ICH-induced BBB dysfunction. There are current clinical trials of minimally invasive hematoma removal and iron chelation which may limit such dysfunction. Understanding the mechanisms underlying the initial hemorrhage and secondary BBB dysfunction in ICH is vital for developing methods to prevent and treat this devastating form of stroke.

In vivo testing of a non-invasive prototype device for the continuous monitoring of intracerebral hemorrhage

BACKGROUND

Intracerebral hemorrhage (ICH) is a stroke subtype with the highest mortality rate. Hematoma expansion and re-bleeding post-ICH are common and exacerbate the initial cerebral insult. There is a need for continuous monitoring of the neurologic status of patients with an ICH injury.

NEW METHOD

A prototype device for non-invasive continuous monitoring of an ICH was developed and tested in vivo using a porcine ICH model. The device consists of receiving and transmitting antennae in the 400-1000 MHz frequency range, placed directly in line with the site of the ICH. The device exploits the differences in the dielectric properties and geometry of tissue media of a healthy brain and a brain with an ICH injury. The power received by the receiving antenna is measured and the percent change in power received immediately after infusion of blood and 30 min after the infusion, allowing for the blood to clot, is calculated.

RESULTS

An increase in the received power in the presence of an ICH is observed at 400 MHz, consistent with previous in vitro studies. Frequency sweep experiments show a maximum percent change in received power in the 750-1000 MHz frequency range.

COMPARISON WITH EXISTING METHODS

Currently, CT, MRI and catheter angiography (CA) are the main clinical neuroimaging modalities. However, these techniques require specialized equipment and personnel, substantial time, and patient-transportation to a radiology suite to obtain results. Moreover, CA is invasive and uses intra-venous dye or vascular catheters to accomplish the imaging.

CONCLUSIONS

The device has the potential to significantly improve neurologic care in the critically ill brain-injured patient.

An in vivo, MRI-integrated real-time model of active contrast extravasation in acute intracerebral hemorrhage

BACKGROUND AND PURPOSE

The "spot sign" or contrast extravasation is strongly associated with hematoma formation and growth. An animal model of contrast extravasation is important to test existing and novel therapeutic interventions to inform present and future clinical studies. The purpose of this study was to create an animal model of contrast extravasation in acute intracerebral hemorrhage.

MATERIALS AND METHODS

Twenty-eight hemispheres of Yorkshire male swine were insonated with an MR imaging-guided focused sonography system following lipid microsphere infusion and mean arterial pressure elevation. The rate of contrast leakage was quantified by using dynamic contrast-enhanced MR imaging and was classified as contrast extravasation or postcontrast leakage by using postcontrast T1. Hematoma volume was measured on gradient recalled-echo MR imaging performed 2 hours postprocedure. Following this procedure, sacrificed brain was subjected to histopathologic examination. Power level, burst length, and blood pressure elevation were correlated with leakage rate, hematoma size, and vessel abnormality extent.

RESULTS

Median (intracerebral hemorrhage) contrast extravasation leakage was higher than postcontrast leakage (11.3; 6.3-23.2 versus 2.4; 1.1-3.1 mL/min/100 g; P<.001). Increasing burst length, gradient recalled-echo hematoma (ρ=0.54; 95% CI, 0.2-0.8; P=.007), and permeability were correlated (ρ=0.55; 95% CI, 0.1-0.8; P=.02). Median permeability (P=.02), gradient recalled-echo hematoma (P=.02), and dynamic contrast-enhanced volumes (P=.02) were greater at 1000 ms than at 10 ms. Within each burst-length subgroup, incremental contrast leakage was seen with mean arterial pressure elevation (ρ=0.2-0.8).

CONCLUSIONS

We describe a novel MR imaging-integrated real-time swine intracerebral hemorrhage model of acute hematoma growth and contrast extravasation.

Progress in translational research on intracerebral hemorrhage: is there an end in sight?

Intracerebral hemorrhage (ICH) is a common and often fatal stroke subtype for which specific therapies and treatments remain elusive. To address this, many recent experimental and translational studies of ICH have been conducted, and these have led to several ongoing clinical trials. This review focuses on the progress of translational studies of ICH including those of the underlying causes and natural history of ICH, animal models of the condition, and effects of ICH on the immune and cardiac systems, among others. Current and potential clinical trials also are discussed for both ICH alone and with intraventricular extension.

Experimental models of brain ischemia: a review of techniques, magnetic resonance imaging, and investigational cell-based therapies

Stroke continues to be a significant cause of death and disability worldwide. Although major advances have been made in the past decades in prevention, treatment, and rehabilitation, enormous challenges remain in the way of translating new therapeutic approaches from bench to bedside. Thrombolysis, while routinely used for ischemic stroke, is only a viable option within a narrow time window. Recently, progress in stem cell biology has opened up avenues to therapeutic strategies aimed at supporting and replacing neural cells in infarcted areas. Realistic experimental animal models are crucial to understand the mechanisms of neuronal survival following ischemic brain injury and to develop therapeutic interventions. Current studies on experimental stroke therapies evaluate the efficiency of neuroprotective agents and cell-based approaches using primarily rodent models of permanent or transient focal cerebral ischemia. In parallel, advancements in imaging techniques permit better mapping of the spatial-temporal evolution of the lesioned cortex and its functional responses. This review provides a condensed conceptual review of the state of the art of this field, from models and magnetic resonance imaging techniques through to stem cell therapies.

Correlation between subacute sensorimotor deficits and brain edema in two mouse models of intracerebral hemorrhage

Formation of brain edema after intracerebral hemorrhage (ICH) is highly associated with its poor outcome. However, the relationship between cerebral edema and behavioral deficits has not been thoroughly examined in the preclinical setting. Hence, this study aimed to evaluate the ability of common sensorimotor tests to predict the extent of brain edema in two mouse models of ICH. One hundred male CD-1 mice were subjected to sham surgery or ICH induction via intrastriatal injection of either autologous blood (30 μL) or bacterial collagenase (0.0375U or 0.075U). At 24 and 72 h after surgery, animals underwent a battery of behavioral tests, including the modified Garcia neuroscore (Neuroscore), corner turn test (CTT), forelimb placing test (FPT), wire hang task (WHT) and beam walking (BW). Brain edema was evaluated via the wet weight/dry weight method. Intrastriatal injection of autologous blood or bacterial collagenase resulted in a significant increase in brain water content and associated sensorimotor deficits (p<0.05). A significant correlation between brain edema and sensorimotor deficits was observed for all behavioral tests except for WHT and BW. Based on these findings, we recommend implementing the Neuroscore, CTT and/or FPT in preclinical studies of unilateral ICH in mice.

NF-κB activation and cell death after intracerebral hemorrhage in patients

Nuclear factor-κB (NF-κB) plays an important role in secondary damage after intracerebral hemorrhage (ICH). We explored NF-κB activation and the relationship between NF-κB and cell death in the perihematomal brain tissue of patients after ICH. According to the interval between onset of hemorrhage and specimen collection, 53 cases of patients with basal ganglia hemorrhage were divided into six experimental groups: 0-6, 7-12, 13-24, 25-48, 49-96, and >96 h group. Brain tissues of the experimental groups and control group were collected. IL-1β, TNF-α, and NF-κB p65 expressions at the protein level were detected by immunohistochemistry. Cell death was detected by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) assay. All of the detection items of immunohistochemistry and TUNEL showed significant differences between the experimental groups and control group. At the protein level, nuclear NF-κB p65, IL-1β, and TNF-α achieved maximum values at 13-48, 0-24, and 13-48 h, respectively. Maximum cell death was reached at 13-48 h. NF-κB activation increased dramatically in perihematomal brain tissue after ICH. NF-κB activation was closely related with cell death and had an important function in secondary brain damage after ICH in patients.

Brain water content. A misunderstood measurement?

Brain edema is a major contributor to poor outcome following ischemic and hemorrhagic stroke. In animal models, edema has historically been quantified as a change in % brain water content (water content/wet weight). As described in this communication, this number can be misleading, as 'small' changes in % brain water content actually reflect much bigger changes in brain swelling. Using either water content, expressed as g/g dry weight, or a measure of brain swelling, better reflect the impact of edema after stroke and brain injury.

Evolution of intracerebral hemorrhage after intravenous tPA: reversal of harmful effects with mast cell stabilization

Thrombolysis with tissue plasminogen activator (tPA) traditionally demands baseline imaging to rule out intracerebral hemorrhage (ICH), which causes delays in treatment. Preventing possible adverse effects of tPA on ICH would allow rapid on-site thrombolysis in patients with presumed acute ischemic stroke, reducing onset-to-treatment times. We examined how intravenous tPA alters ICH evolution during an extended follow-up, and how mast cell stabilization affects this process. Intracerebral hemorrhage was induced in rats by collagenase injection. Rats received either saline (n=10), tPA (n=13), tPA+low-dose cromoglycate (n=10), or tPA+high-dose cromoglycate (n=10). Magnetic resonance imaging was performed at 24, 48, and 72 hours after ICH induction, together with neurologic evaluations. During 72 hours of follow-up, tPA administration did not significantly increase hematoma volume (mean±s.d. 83.5±14.3 versus 66.7±14.7 μL; P=0.256) or hemispheric expansion (14.5±5.0 versus 11.5±5.0%; P=0.457) compared with saline. However, tPA-treated animals had worse neurologic outcomes (P<0.05), and mortality (8/13 versus 3/10). Combining tPA with high-dose cromoglycate mitigated hemispheric expansion (7.4±1.7 versus 14.5±5.0%; P=0.01), improved neurologic outcome (P<0.001) and decreased mortality (1/10; P<0.05) compared with tPA alone. Our results suggest tPA increases neurologic deficit in ICH, an effect that was abolished by concomitant mast cell stabilization. Further studies are needed to establish the clinical relevance of these findings.

Alpha-7 nicotinic acetylcholine receptor agonists in intracerebral hemorrhage: an evaluation of the current evidence for a novel therapeutic agent

Intracerebral hemorrhage (ICH) is the most deadly and least treatable subtype of stroke, and at the present time there are no evidence-based therapeutic interventions for patients with this disease. Secondary injury mechanisms are known to cause substantial rates of morbidity and mortality following ICH, and the inflammatory cascade is a major contributor to this post-ICH secondary injury. The alpha-7 nicotinic acetylcholine receptor (α7-nAChR) agonists have a well-established antiinflammatory effect and have been shown to attenuate perihematomal edema volume and to improve functional outcome in experimental ICH. The authors evaluate the current evidence for the use of an α7-nAChR agonist as a novel therapeutic agent in patients with ICH.

Experimental model of intracranial hypertension with continuous multiparametric monitoring in swine

Objective Intracranial hypertension (IH) develops in approximately 50% of all patients with severe traumatic brain injury (TBI). Therefore, it is very important to identify a suitable animal model to study and understand the pathophysiology of refractory IH to develop effective treatments. Methods We describe a new experimental porcine model designed to simulate expansive brain hematoma causing IH. Under anesthesia, IH was simulated with a balloon insufflation. The IH variables were measured with intracranial pressure (ICP) parenchymal monitoring, epidural, cerebral oximetry, and transcranial Doppler (TCD). Results None of the animals died during the experiment. The ICP epidural showed a slower rise compared with parenchymal ICP. We found a correlation between ICP and cerebral oximetry. Conclusion The model described here seems useful to understand some of the pathophysiological characteristics of acute IH.

Modulation of crucial adenosinetriphosphatase activities due to U-74389G administration in a porcine model of intracerebral hemorrhage

Spontaneous intracerebral hemorrhage (ICH) represents a partially-understood cerebrovascular disease of high incidence, morbidity and mortality. We, herein, report the findings of our study concerning the role of two important adenosinetriphosphatases (ATPases) in a porcine model of spontaneous ICH that we have recently developed (by following recent references as well as previously-established models and techniques), with a focus on the first 4 and 24 h following the lesion's induction, in combination with a study of the effectiveness of the lazaroid antioxidant U-74389G administration. Our study demonstrates that the examined ICH model does not cause a decrease in Na(+),K(+)-ATPase activity (the levels of which are responsible for a very large part of neuronal energy expenditure) in the perihematomal basal ganglia territory, nor a change in the activity of Mg(2+)-ATPase. This is the first report focusing on these crucial ATPases in the experimental setting of ICH and differs from the majority of the findings concerning the behavior of these (crucial for central nervous system cell survival) enzymes under stroke-related ischemic conditions. The administration of U-74389G (an established antioxidant) in this ICH model revealed an injury specific type of behavior, that could be considered as neuroprotective provided that one considers that Na(+),K(+)- and Mg(2+)-ATPase inhibition might in this case diminish the local ATP consumption.

Tumor necrosis factor α antagonism improves neurological recovery in murine intracerebral hemorrhage

Background

Intracerebral hemorrhage (ICH) is a devastating stroke subtype characterized by a prominent neuroinflammatory response. Antagonism of pro-inflammatory cytokines by specific antibodies represents a compelling therapeutic strategy to improve neurological outcome in patients after ICH. To test this hypothesis, the tumor necrosis factor alpha (TNF-α) antibody CNTO5048 was administered to mice after ICH induction, and histological and functional endpoints were assessed.

Methods

Using 10 to 12-week-old C57BL/6J male mice, ICH was induced by collagenase injection into the left basal ganglia. Brain TNF-α concentration, microglia activation/macrophage recruitment, hematoma volume, cerebral edema, and rotorod latency were assessed in mice treated with the TNF-α antibody, CNTO5048, or vehicle.

Results

After ICH induction, mice treated with CNTO5048 demonstrated reduction in microglial activation/macrophage recruitment compared to vehicle-treated animals, as assessed by unbiased stereology (P = 0.049). This reduction in F4/80-positive cells was associated with a reduction in cleaved caspase-3 (P = 0.046) and cerebral edema (P = 0.026) despite similar hematoma volumes, when compared to mice treated with vehicle control. Treatment with CNTO5048 after ICH induction was associated with a reduction in functional deficit when compared to mice treated with vehicle control, as assessed by rotorod latencies (P = 0.024).

Conclusions

Post-injury treatment with the TNF-α antibody CNTO5048 results in less neuroinflammation and improved functional outcomes in a murine model of ICH.

New Horizons for Primary Intracerebral Hemorrhage Treatment: Experience From Preclinical Studies

Intracerebral hemorrhage (ICH) remains a major medical problem, for which there is no effective treatment. However, extensive experimental and clinical research carried out in recent years has brought to light new exciting ideas for novel potential treatments. First, it was well documented that the management of hypertension helps to prevent new and recurrent ICH. Also, development of new guidelines for management of hypertension after the onset of the ICH may help in more effective ICH treatment. Existing contemporary data collected from preclinical studies indicates that ICH-induced inflammation represents a key factor leading to secondary brain damage, suggesting that some anti-inflammatory approaches can be used to treat hemorrhagic stroke. In this article, beyond discussing implications related to hypertension, we will summarize important (but not all) new discoveries connecting the role of inflammation to ICH pathology. Selected aspects of inflammatory response including the role of cytokines, transcription factor nuclear factor-kB, microglia activation, astrogliosis, and complement activation will be introduced. We will also discuss the role for reactive oxygen species and metalloproteinases in ICH pathogenesis and introduce basic knowledge on the nature of ICH-induced cell death including apoptosis. Potential targets for intervention and translation will be discussed.

Brain microbleeds: distribution and influence on hematoma and perihematomal edema in patients with primary intracerebral hemorrhage

Brain microbleed is a marker of small vessel microhemorrhagic or microaneurysmal lesions, which may induce intracerebral hemorrhage (ICH). This study to prospectively evaluated the association between microbleeds, hematoma and perihematomal edema volume, and various clinical data, as well as patient outcome. Thirty-one patients with ICH and 31 healthy age-matched subjects were enrolled in our study. They were divided into two groups according to the presence or absence of microbleeds detected by MRI. Serial clinical and laboratory data were recorded. Modified Rankin Scale and Barthel Index were estimated three months after hemorrhage. The major location of microbleeds among patients with ICH was the basal ganglia. The volume of perihematomal edema was correlated with the initial hematoma volume on the first, fifth and seventh days after hemorrhage in patients with microbleeds. For patients without microbleeds, this correlation was also significant on the seventh day. Cerebral microbleeds in patients with ICH, especially in the basal ganglia region, represent micro-angiopathy, and are associated with leakage of blood and formation of perihemorrhage edema. Brain microbleeds found in patients with ICH warrant further investigation for evaluation of stroke risk.

Experimental high-altitude intracerebral hemorrhage in minipigs: histology, behavior, and intracranial pressure in a double-injection model

BACKGROUND

Specific pathophysiological mechanism in intracerebral hemorrhage (ICH) at high altitude is unclear, and at present, there is no relevant and suitable animal model.

METHODS

A hypobaric chamber was used to simulate an altitude of 4,000 m. Autologous arterial blood (3 ml) was slowly infused into the right basal ganglia of minipigs by a double-injection method for producing ICH.

RESULTS

The intracranial pressure and neurological score of the high-altitude group were significantly higher than those of the low-altitude (plain) group. The brain water contents and pathological lesions of perihematoma tissue were more severe in the high-altitude group.

CONCLUSIONS

The injury resulting from ICH at high altitude was more severe than that in the plain group. This model was able to produce controllable and reproducible hematomas and visible neurological deficits, which may be useful for future studies of the pathophysiology and functional rehabilitation of high-altitude ICH disease.

Minimally invasive treatment of intracerebral hemorrhage with magnetic resonance-guided focused ultrasound

OBJECT

Intracerebral hemorrhage (ICH) is a major cause of death and disability throughout the world. Surgical techniques are limited by their invasive nature and the associated disability caused during clot removal. Preliminary data have shown promise for the feasibility of transcranial MR-guided focused ultrasound (MRgFUS) sonothrombolysis in liquefying the clotted blood in ICH and thereby facilitating minimally invasive evacuation of the clot via a twist-drill craniostomy and aspiration tube.

METHODS AND RESULTS

In an in vitro model, the following optimum transcranial sonothrombolysis parameters were determined: transducer center frequency 230 kHz, power 3950 W, pulse repetition rate 1 kHz, duty cycle 10%, and sonication duration 30 seconds. Safety studies were performed in swine (n = 20). In a swine model of ICH, MRgFUS sonothrombolysis of 4 ml ICH was performed. Magnetic resonance imaging and histological examination demonstrated complete lysis of the ICH without additional brain injury, blood-brain barrier breakdown, or thermal necrosis due to sonothrombolysis. A novel cadaveric model of ICH was developed with 40-ml clots implanted into fresh cadaveric brains (n = 10). Intracerebral hemorrhages were successfully liquefied (> 95%) with transcranial MRgFUS in a highly accurate fashion, permitting minimally invasive aspiration of the lysate under MRI guidance.

CONCLUSIONS

The feasibility of transcranial MRgFUS sonothrombolysis was demonstrated in in vitro and cadaveric models of ICH. Initial in vivo safety data in a swine model of ICH suggest the process to be safe. Minimally invasive treatment of ICH with MRgFUS warrants evaluation in the setting of a clinical trial.

Computed tomography and transcranial Doppler findings in acute and subacute phases of intracerebral hemorrhagic stroke

BACKGROUND AND PURPOSE

The hematoma volume is an important determinant of outcome and a predictor of clinical deterioration in patients with intracerebral hemorrhage (ICH). Our goal was to evaluate alterations in the cerebral circulation, in respect to hemorrhage and edema volume changes, using transcranial Doppler (TCD).

METHODS

Twenty patients with acute supratentorial ICH were examined. Brain, hematoma, and edema volumes were calculated from CT scans performed at admission and 2 weeks later. Data were compared with those obtained from bilateral TCD recordings of the middle cerebral arteries.

RESULTS

During TCD examination, blood flow velocities did not change, cerebral perfusion pressure (CPP) and resistance area product (RAP) decreased (P = .006, P = .002) while cerebral blood flow index (CBFI) remained constant on the affected side. Although hemorrhage volume did not correlate with RAP in the acute phase, correlation was found in the subacute phase (r = -.44, P = .04).

CONCLUSIONS

TCD monitoring sensitively demonstrates the hemodynamic change caused by ICH but the severity of the changes does not correlate with the volume of the ICH in acute stage. The CPP, RAP, and CBFI values are more sensitive parameters than the absolute velocity values, therefore they contribute more to the understanding of hemodynamic changes developed after spontaneous ICH.

Thrombin and hemin as central factors in the mechanisms of intracerebral hemorrhage-induced secondary brain injury and as potential targets for intervention

Intracerebral hemorrhage (ICH) is a subtype of stoke that may cause significant morbidity and mortality. Brain injury due to ICH initially occurs within the first few hours as a result of mass effect due to hematoma formation. However, there is increasing interest in the mechanisms of secondary brain injury as many patients continue to deteriorate clinically despite no signs of rehemorrhage or hematoma expansion. This continued insult after primary hemorrhage is believed to be mediated by the cytotoxic, excitotoxic, oxidative, and inflammatory effects of intraparenchymal blood. The main factors responsible for this injury are thrombin and erythrocyte contents such as hemoglobin. Therapies including thrombin inhibitors, N-methyl-D-aspartate antagonists, chelators to bind free iron, and antiinflammatory drugs are currently under investigation for reducing this secondary brain injury. This review will discuss the molecular mechanisms of brain injury as a result of intraparenchymal blood, potential targets for therapeutic intervention, and treatment strategies currently in development.

Intracerebral haemorrhage: mechanisms of injury and therapeutic targets

Intracerebral haemorrhage accounts for about 10-15% of all strokes and is associated with high mortality and morbidity. No successful phase 3 clinical trials for this disorder have been completed. In the past 6 years, the number of preclinical and clinical studies focused on intracerebral haemorrhage has risen. Important advances have been made in animal models of this disorder and in our understanding of mechanisms underlying brain injury after haemorrhage. Several therapeutic targets have subsequently been identified that are now being pursued in clinical trials. Many clinical trials have been based on limited preclinical data, and guidelines to justify taking preclinical results to the clinic are needed.

Activation of acetylcholinesterase after U-74389G administration in a porcine model of intracerebral hemorrhage

Spontaneous intracerebral hemorrhage (ICH) accounts for 10-15% of all strokes. Despite high incidence, morbidity and mortality, the precise pathophysiology of spontaneous ICH is not fully understood, while there is little data concerning the mechanisms that follow the primary insult of the hematoma formation. The cholinergic system, apart from its colossal importance as a neurotransmission system, seems to also play an important role in brain injury recovery. It has been recently suggested that the brain possesses a cholinergic anti-inflammatory pathway that counteracts the inflammatory responses after ICH, thereby limiting damage to the brain itself. We, herein, report the findings of our study concerning the role of acetylcholinesterase (AChE; a crucial membrane-bound enzyme involved in cholinergic neurotransmission) in a porcine model of spontaneous ICH, with a focus on the first 4 and 24 h following the lesion's induction, in combination with a study of the effectiveness of the lazaroid antioxidant U-74389G administration. Our study demonstrates the activation of AChE activity following U-74389G administration. The lazaroid U-74389G seems to be an established neuroprotectant and this is the first report of its supporting role in the enhancement of cholinergic response to the induction of ICH.

Translating basic science research to clinical application: models and strategies for intracerebral hemorrhage

Preclinical stroke models provide insights into mechanisms of cellular injury and potential therapeutic targets. Renewed efforts to standardize preclinical practices and adopt more rigorous approaches reflect the assumption that a better class of compounds will translate into clinical efficacy. While the need for novel therapeutics is clear, it is also critical that diagnostics be improved to allow for more rapid treatment upon hospital admission. Advances in imaging techniques have aided in the diagnosis of stroke, yet current limitations and expenses demonstrate the need for new and complementary approaches. Intracerebral hemorrhage (ICH) exhibits the highest mortality rate, displays unique pathology and requires specialized treatment strategies relative to other forms of stroke. The aggressive nature and severe consequences of ICH underscore the need for novel therapeutic approaches as well as accurate and expeditious diagnostic tools. The use of experimental models will continue to aid in addressing these important issues as the field attempts to translate basic science findings into the clinical setting. Several preclinical models of ICH have been developed and are widely used to recapitulate human pathology. Because each model has limitations, the burden lies with the investigator to clearly define the question being asked and select the model system that is most relevant to that question. It may also be necessary to optimize and refine pre-existing paradigms, or generate new paradigms, as the future success of translational research is dependent upon the ability to mimic human sequelae and assess clinically relevant outcome measures as means to evaluate therapeutic efficacy.

Tissue plasminogen activator induced delayed edema in experimental porcine intracranial hemorrhage: reduction with plasminogen activator inhibitor-1 administration

Hematoma puncture and subsequent clot lysis with recombinant tissue plasminogen activator (rtPA) emerged as an alternative therapy for spontaneous intracerebral hemorrhage (ICH) and is associated with delayed edema possibly counteracting the beneficial effects of hematoma volume reduction. We hypothesized that immediate reversal of rtPA activity after clot lysis and hematoma drainage diminishes edema formation. To test this hypothesis, we administered plasminogen activator inhibitor (PAI)-1 after rtPA lysis of experimentally induced ICH. A right frontal ICH was placed through a twist drill burr hole and autologous blood injection. Following creation of the frontal ICH, pigs received no further treatment (n = 5), lysis with rtPA (n = 7), or lysis with rtPA followed by administration of PAI-1 (n = 6). Hematoma and edema volumes were assessed with magnetic resonance imaging on days 0, 4, and 10. The rtPA significantly reduced hematoma volume and contributed to edema on day 10 after experimentally induced ICH. Administration of PAI-1 attenuated the rtPA-induced edema volume on day 10, but the hematoma volume reduction was less pronounced. In conclusion, PAI-1 attenuated delayed cerebral edema after rtPA lysis of experimental ICH but also reduced the lytic activity of rtPA. The combination of rtPA clot lysis with PAI-1 might have the potential to further improve the effect of the lytic therapy of ICH, but additional studies to define the optimum time point for PAI-1 administration are required.

Poor correlation between perihematomal MRI hyperintensity and brain swelling after intracerebral hemorrhage

BACKGROUND AND PURPOSE

The perihematomal hyperintensity (PHH) is commonly interpreted to represent cerebral edema following intracerebral hemorrhage (ICH), but the accuracy of this interpretation is unknown. We therefore investigated the relationship between the changes in PHH and the changes in hemispheric brain volume as a measure of edema during the first week after ICH.

METHODS

Fifteen individuals aged 66 ± 13 with baseline hematoma size of 13.1 ml (range 3-43) were prospectively studied with sequential MRI 1.0 ± 0.5, 2.6 ± 0.9, and 6.5 ± 1.0 days after spontaneous supratentorial ICH. Changes in hemispheric brain volume were assessed on MPRAGE using the Brain-Boundary Shift Integral (BBSI). Hematoma and PHH volumes were measured on T2-weighted images.

RESULTS

Brain volume increased a small but statistically significant amount (6.3 ± 8.0 ml, 0.6 ± 0.7%) between the first and second scans relative to 10 normal controls (-0.9 ± 4.1 ml, P = 0.02) and returned toward baseline at the third scan (1.5 ± 9.5 ml vs. controls 0.9 ± 4.0 ml, P = 0.85). There were no significant differences in the volume changes between the two hemispheres at scan 2 or scan 3. At both scan 2 (P = 0.04) and scan 3 (P = 0.004), the change in PHH was significantly greater than and poorly correlated with the change in ipsilateral hemispheric volume. There were no significant correlations between the change in NIH Stroke Scale (NIHSS) and the change in PHH, ipsilateral, or total brain volume at scan 2 or scan 3 (all P > 0.05).

CONCLUSIONS

In patients with small-to-moderate-sized hematomas, change in PHH was a poor measure of brain edema in the first week following ICH. A small degree of bihemispheric brain swelling occurred, but was of little clinical significance.

Intracerebral hemorrhage: clinical overview and pathophysiologic concepts

Intracerebral hemorrhage is by far the most destructive form of stroke. Apart from the management in a specialized stroke or neurological intensive care unit (NICU), no specific therapies have been shown to consistently improve outcomes after ICH. Current guidelines endorse early aggressive optimization of physiologic derangements with ventilatory support when indicated, blood pressure control, reversal of any preexisting coagulopathy, intracranial pressure monitoring for certain cases, osmotherapy, temperature modulation, seizure prophylaxis, treatment of hyerglycemia, and nutritional support in the stroke unit or NICU. Ventriculostomy is the cornerstone of therapy for control of intracranial pressure patients with intraventricular hemorrhage. Surgical hematoma evacuation does not improve outcome for more patients, but is a reasonable option for patients with early worsening due to mass effect due to large cerebellar or lobar hemorrhages. Promising experimental treatments currently include ultra-early hemostatic therapy, intraventricular clot lysis with thrombolytics, pioglitazone, temperature modulation, and deferoxamine to reduce iron-mediated perihematomal inflammation and tissue injury.

Chinese Herb Astragalus membranaceus Enhances Recovery of Hemorrhagic Stroke: Double-Blind, Placebo-Controlled, Randomized Study

We tested the effect of Astragalus membranaceus (AM) on acute hemorrhagic stroke. Seventy-eight patients were randomly assigned to Group A (3 g of AM three times/day for 14 days); or Group B (3 g of placebo herb). A total of 68 patients (Group A 36, Group B 32) completed the trial. The increase of functional independence measure scale score between baseline and week 4 was 24.53 ± 23.40, and between baseline and week 12 was 34.69 ± 28.89, in the Group A was greater than 11.97 ± 11.48 and 23.94 ± 14.8 in the Group B (both P≦0.05). The increase of Glasgow outcome scale score between baseline and week 12 was 0.75 ± 0.77 in the Group A was greater than 0.41 ± 0.50 in the Group B (P < 0.05). The results are preliminary and need a larger study to assess the efficacy of AM after stroke.

Inhibition of carbonic anhydrase reduces brain injury after intracerebral hemorrhage

Carbonic anhydrase-1 (CA-1) is a metalloenzyme present at high concentrations in erythrocytes. Our previous studies showed that erythrocyte lysis contributes to brain edema formation after intracerebral hemorrhage (ICH) and a recent study indicates that CA-1 can cause blood-brain barrier disruption. The present study investigated the role of CA-1 in ICH-induced brain injury.There were three groups in the study. In the first, adult male Sprague-Dawley rats received 100 μl autologous blood injection into the right caudate. Sham rats had a needle insertion. Rat brains were used for brain CA-1 level determination. In the second group, rats received an intracaudate injection of either 50 μl CA-1 (1 μg/μl) or saline. Brain water content, microglia activation and neuronal death (Fluoro-Jade C staining) were examined 24 hours later. In the third group, acetazolamide (AZA, 5 μl, 1 mM), an inhibitor of carbonic anhydrases, or vehicle was co-injected with 100 μl blood. Brain water content, neuronal death and behavioral deficits were measured. We found that CA-I levels were elevated in the ipsilateral basal ganglia at 24 hours after ICH. Intracaudate injection of CA-1 induced brain edema (79.0 ± 0.6 vs. 78.0±0.2% in saline group, p<0.01), microglia activation and neuronal death (p<0.01) at 24 hours. AZA, an inhibitor of CA, reduced ICH-induced brain water content (79.3 ± 0.7 vs. 81.0 ± 1.0% in the vehicle-treated group, p<0.05), neuronal death and improved functional outcome (p<0.05).These results suggest that CA-1 from erythrocyte lysis contributes to brain injury after ICH.