Intracerebral hemorrhage: a multimodality approach to improving outcome

Cerebrospinal fluid predictors of shunt-dependent hydrocephalus after hemorrhagic stroke: a systematic review and meta-analysis

Hydrocephalus is a common complication of hemorrhagic stroke and has been reported to contribute to poor neurological outcomes. Herein, we aimed to investigate the validity of cerebrospinal fluid (CSF) data in predicting shunt-dependent hydrocephalus (SDHC) in patients with hemorrhagic stroke. PubMed, CENTRAL, and Embase databases were searched for relevant studies published through July 31, 2021. The 16 studies with 1505 patient included those in which CSF data predicted risk for SDHC and reports on CSF parameters in patients in whom SDHC or hydrocephalus that was not shunt-dependent developed following hemorrhagic stroke. We appraised the study quality using Newcastle-Ottawa Scale and conducted a meta-analysis of the pooled estimates of the CSF predictors. The meta-analysis revealed three significant CSF predictors for shunt dependency, i.e., higher protein levels (mean difference [MD] = 32.09 mg/dL, 95% confidence interval [CI] = 25.48-38.70, I² = 0%), higher levels of transforming growth factor β1 (TGF-β1; MD = 0.52 ng/mL, 95% CI = 0.42-0.62, I² = 0%), and higher ferritin levels (MD = 108.87 µg/dL, 95% CI = 56.68-161.16, I² = 36%). The red blood cell count, lactate level, and glucose level in CSF were not significant in predicting SDHC in patients with hemorrhagic stroke. Therefore, higher protein, TGF-β1, and ferritin levels in CSF are significant predictors for SDHC in patients with hemorrhagic stroke. Measuring these CSF parameters would help in the early recognition of SDHC risk in clinical care.

Poly-arginine-18 peptides do not exacerbate bleeding, or improve functional outcomes following collagenase-induced intracerebral hemorrhage in the rat

Background

Cationic arginine-rich peptides (CARPs) have demonstrated neuroprotective and/or behavioural efficacy in ischemic and hemorrhagic stroke and traumatic brain injury models. Therefore, in this study we investigated the safety and neuroprotective efficacy of the CARPs poly-arginine-18 (R18; 18-mer of arginine) and its D-enantiomer R18D given in the acute bleeding phase in an intracerebral hemorrhage (ICH) model.

Methods

One hundred and fifty-eight male Sprague-Dawley rats received collagenase-induced ICH. Study 1 examined various doses of R18D (30, 100, 300, or 1000 nmol/kg) or R18 (100, 300, 1000 nmol/kg) administered intravenously 30 minutes post-collagenase injection on hemorrhage volume 24 hours after ICH. Study 2 examined R18D (single intravenous dose) or R18 (single intravenous dose, plus 6 daily intraperitoneal doses) at 300 or 1000 nmol/kg commencing 30 minutes post-collagenase injection on behavioural outcomes (Montoya staircase test, and horizontal ladder test) in the chronic post-ICH period. A histological assessment of tissue loss was assessed using a Nissl stain at 28 days after ICH.

Results

When administered during ongoing bleeding, neither R18 or R18D exacerbated hematoma volume or worsened functional deficits. Lesion volume assessment at 28 days post-ICH was not reduced by the peptides; however, animals treated with the lower R18D 300 nmol/kg dose, but not with the higher 1000 nmol/kg dose, demonstrated a statistically increased lesion size compared to saline treated animals.

Conclusion

Overall, both R18 and R18D appeared to be safe when administered during a period of ongoing bleeding following ICH. Neither peptide appears to have any statistically significant effect in reducing lesion volume or improving functional recovery after ICH. Additional studies are required to further assess dose efficacy and safety in pre-clinical ICH studies.

Hematoma Expansion Following Intracerebral Hemorrhage: Mechanisms Targeting the Coagulation Cascade and Platelet Activation

Hematoma expansion (HE), defined as a greater than 33% increase in intracerebral hemorrhage (ICH) volume within the first 24 hours, results in significant neurological deficits, and enhancement of ICH-induced primary and secondary brain injury. An escalation in the use of oral anticoagulants has led to a surge in the incidences of oral anticoagulation-associated ICH (OAT-ICH), which has been associated with a greater risk for HE and worse functional outcomes following ICH. The oral anticoagulants in use include vitamin K antagonists, and direct thrombin and factor Xa inhibitors. Fibrinolytic agents are also frequently administered. These all act via differing mechanisms and thus have varying degrees of impact on HE and ICH outcome. Additionally, antiplatelet medications have also been increasingly prescribed, and result in increased bleeding risks and worse outcomes after ICH. Aspirin, thienopyridines, and GPIIb/IIIa receptor blockers are some of the most common agents in use clinically, and also have different effects on ICH and hemorrhage growth, based on their mechanisms of action. Recent studies have found that reduced platelet activity may be more effective in predicting ICH risk, hemorrhage expansion, and outcomes, than antiplatelet agents, and activating platelets may thus be a novel target for ICH therapy. This review explores how dysfunctions or alterations in the coagulation and platelet cascades can lead to, and/or exacerbate, hematoma expansion following intracerebral hemorrhage, and describe the mechanisms behind these effects and the drugs that induce them. We also discuss potential future therapy aimed at increasing platelet activity after ICH.

Perihematomal Edema Expansion Rates and Patient Outcomes in Deep and Lobar Intracerebral Hemorrhage

BACKGROUND

Perihematomal edema (PHE) expansion rate may predict functional outcome following spontaneous intracerebral hemorrhage (ICH). We hypothesized that the effect of PHE expansion rate on outcome is greater for deep versus lobar ICH.

METHODS

Subjects (n = 115) were retrospectively identified from a prospective ICH cohort enrolled from 2000 to 2013. Inclusion criteria were age ≥ 18 years, spontaneous supratentorial ICH, and known onset time. Exclusion criteria were primary intraventricular hemorrhage (IVH), trauma, subsequent surgery, or warfarin-related ICH. ICH and PHE volumes were measured from CT scans and used to calculate expansion rates. Logistic regression assessed the association between PHE expansion rates and 90-day mortality or poor functional outcome (modified Rankin Scale > 2). Odds ratios are per 0.04 mL/h.

RESULTS

PHE expansion rate from baseline to 24 h (PHE24) was associated with mortality for deep (p = 0.03, OR 1.13[1.02-1.26]) and lobar ICH (p = 0.02, OR 1.03[1.00-1.06]) in unadjusted regression and in models adjusted for age (deep p = 0.02, OR 1.15[1.02-1.28]; lobar p = 0.03, OR 1.03[1.00-1.06]), Glasgow Coma Scale (deep p = 0.03, OR 1.13[1.01-1.27]; lobar p = 0.02, OR 1.03[1.01-1.06]), or time to baseline CT (deep p = 0.046, OR 1.12[1.00-1.25]; lobar p = 0.047, OR 1.03[1.00-1.06]). PHE expansion rate from baseline to 72 h (PHE72) was associated with mRS > 2 for deep ICH in models that were unadjusted (p = 0.02, OR 4.04[1.25-13.04]) or adjusted for ICH volume (p = 0.02, OR 4.3[1.25-14.98]), age (p = 0.03, OR 5.4[1.21-24.11]), GCS (p = 0.02, OR 4.19[1.2-14.55]), or time to first CT (p = 0.03, OR 4.02[1.19-13.56]).

CONCLUSIONS

PHE72 was associated with poor functional outcomes after deep ICH, whereas PHE24 was associated with mortality for deep and lobar ICH.

GSK-3β Inhibition Induced Neuroprotection, Regeneration, and Functional Recovery After Intracerebral Hemorrhagic Stroke

Hemorrhagic stroke is a devastating disease that lacks effective therapies. In the present investigation, we tested 6-bromoindirubin-3'-oxime (BIO) as a selective glycogen synthase kinase-3β (GSK-3β) inhibitor in a mouse model of intracerebral hemorrhage (ICH). ICH was induced by injection of collagenase IV into the striatum of 8- to 10-week-old C57BL/6 mice. BIO (8 μg/kg, IP) was administered following either an acute delivery (0-2 h delay) or a prolonged regimen (every 48 h starting at 3 days post-ICH). At 2 days post-ICH, the acute BIO treatment significantly reduced the hematoma volume. In the perihematoma regions, BIO administration blocked GSK-3β phosphorylation/activation, increased Bcl-2 and β-catenin levels, and significantly increased viability of neurons and other cell types. The prolonged BIO regimen maintained a higher level of β-catenin, upregulated VEGF and BDNF, and promoted neurogenesis and angiogenesis in peri-injury zones at 14 days after ICH. The BIO treatment also promoted proliferation of neural stem cells (NSCs) and migration of nascent DCX+ neuroblasts from the subventricular zone (SVZ) to the lesioned cortex. BIO improved functional outcomes on both the neurological severity score and rotarod tests. The findings of this study corroborate the neuroprotective and regenerative effects of BIO and suggest that the Wnt/GSK-3β/β-catenin pathway may be explored for the treatment of acute or chronic ICH.

Hyperbaric oxygen therapy and preconditioning for ischemic and hemorrhagic stroke

To date, the therapeutic methods for ischemic and hemorrhagic stroke are still limited. The lack of oxygen supply is critical for brain injury following stroke. Hyperbaric oxygen (HBO), an approach through a process in which patients breathe in 100% pure oxygen at over 101 kPa, has been shown to facilitate oxygen delivery and increase oxygen supply. Hence, HBO possesses the potentials to produce beneficial effects on stroke. Actually, accumulated basic and clinical evidences have demonstrated that HBO therapy and preconditioning could induce neuroprotective functions via different mechanisms. Nevertheless, the lack of clinical translational study limits the application of HBO. More translational studies and clinical trials are needed in the future to develop effective HBO protocols.

Recent Advances of the NLRP3 Inflammasome in Central Nervous System Disorders

Inflammasomes are multiprotein complexes that trigger the activation of caspases-1 and subsequently the maturation of proinflammatory cytokines interleukin-1β and interleukin-18. These cytokines play a critical role in mediating inflammation and innate immunity response. Among various inflammasome complexes, the NLRP3 inflammasome is the best characterized, which has been demonstrated as a crucial role in various diseases. Here, we review recently described mechanisms that are involved in the activation and regulation of NLRP3 inflammasome. In addition, we summarize the recent researches on the role of NLRP3 inflammasome in central nervous system (CNS) diseases, including traumatic brain injury, ischemic stroke and hemorrhagic stroke, brain tumor, neurodegenerative diseases, and other CNS diseases. In conclusion, the NLRP3 inflammasome may be a promising therapeutic target for these CNS diseases.

Hyperbaric oxygen therapy in experimental and clinical stroke

Stroke, which is defined as a neurologic deficit caused by sudden impaired blood supply, has been considered as a common cause of death and disability for decades. The World Health Organization has declared that almost every 5 seconds a new stroke occurs, placing immense socioeconomic burdens. However, the effective and available treatment strategies are still limited. Additionally, the most effective therapy, such as thrombolysis and stenting for ischemic stroke, generally requires a narrow therapeutic time window after the event. A large majority of patients cannot be admitted to hospital and receive these effective treatments for reperfusion timely. Hyperbaric oxygen therapy (HBOT) has been frequently applied and investigated in stroke since 1960s. Numerous basic and clinical studies have shown the beneficial efficacy for neurological outcome after stroke, and meanwhile many underlying mechanisms associated with neuroprotection have been illustrated, such as cerebral oxygenation promotion and metabolic improvement, blood-brain barrier protection, anti-inflammation and cerebral edema, intracranial pressure modulation, decreased oxidative-stress and apoptosis, increased vascular and neural regeneration. However, HBOT in human stroke is still not sufficiently evidence-based, due to the insufficient randomized double-blind controlled clinical studies. To date, there are no uniform criteria for the dose and session duration of HBOT in different strokes. Furthermore, the additional effect of HBOT combined with drugs and other treatment strategies are being investigated recently. Therefore, more experimental and clinical research is imperative to identify the mechanisms more clearly and to explore the best protocol of HBOT in stroke treatment.

Critical Role of the Sphingolipid Pathway in Stroke: a Review of Current Utility and Potential Therapeutic Targets

Sphingolipids are a series of cell membrane-derived lipids which act as signaling molecules and play a critical role in cell death and survival, proliferation, recognition, and migration. Sphingosine-1-phosphate acts as a key signaling molecule and regulates lymphocyte trafficking, glial cell activation, vasoconstriction, endothelial barrier function, and neuronal death pathways which plays a critical role in numerous neurological conditions. Stroke is a second leading cause of death all over the world and effective therapies are still in great demand, including ischemic stroke and hemorrhagic stroke as well as poststroke repair. Significantly, sphingolipid activities change after stroke and correlate with stroke outcome, which has promoted efforts to testify whether the sphingolipid pathway could be a novel therapeutic target in stroke. The sphingolipid metabolic pathway, the connection between the pathway and stroke, as well as therapeutic interventions to manipulate the pathway to reduce stroke-induced brain injury are discussed in this review.

Intracerebral Hemorrhage, Oxidative Stress, and Antioxidant Therapy

Hemorrhagic stroke is a common and severe neurological disorder and is associated with high rates of mortality and morbidity, especially for intracerebral hemorrhage (ICH). Increasing evidence demonstrates that oxidative stress responses participate in the pathophysiological processes of secondary brain injury (SBI) following ICH. The mechanisms involved in interoperable systems include endoplasmic reticulum (ER) stress, neuronal apoptosis and necrosis, inflammation, and autophagy. In this review, we summarized some promising advances in the field of oxidative stress and ICH, including contained animal and human investigations. We also discussed the role of oxidative stress, systemic oxidative stress responses, and some research of potential therapeutic options aimed at reducing oxidative stress to protect the neuronal function after ICH, focusing on the challenges of translation between preclinical and clinical studies, and potential post-ICH antioxidative therapeutic approaches.

Hyperbaric oxygen preconditioning: a reliable option for neuroprotection

Brain injury is the leading cause of death and disability worldwide and clinically there is no effective therapy for neuroprotection. Hyperbaric oxygen preconditioning (HBO-PC) has been experimentally demonstrated to be neuroprotective in several models and has shown efficiency in patients undergoing on-pump coronary artery bypass graft (CABG) surgery. Compared with other preconditioning stimuli, HBO is benign and has clinically translational potential. In this review, we will summarize the results in experimental brain injury and clinical studies, elaborate the mechanisms of HBO-PC, and discuss regimes and opinions for future interventions in acute brain injury.

Functional outcome after intracerebral haemorrhage – a review of the potential role of antiapoptotic agents

Intracerebral haemorrhage (ICH) is the second most common form of stroke and is associated with greater mortality and morbidity compared with ischaemic stroke. The current ICH management strategies, which mainly target primary injury mechanisms, have not been shown to improve patient’s functional outcome. Consequently, multimodality treatment approaches that will focus on both primary and secondary pathophysiology have been suggested. During the last decade, a proliferation of experimental studies has demonstrated the role of apoptosis in secondary neuronal loss at the periphery of the clot after ICH. Subsequently, the value of certain antiapoptotic agents in reducing neuronal death and improving functional outcome following ICH was evaluated in animal models. Preliminary evidence from those studies strongly supports the potential role of antiapoptotic agents in reducing neuronal death and improving functional outcome after intracerebral haemorrhage. Expectedly, the ongoing and subsequent clinical trials will substantiate these findings and provide clear information on the most potent and safe antiapoptotic agents, their appropriate dosage, and temporal window of action, thereby making them suitable for the multimodality treatment approach.

Zinc Protoporphyrin Attenuates White Matter Injury after Intracerebral Hemorrhage

Intracerebral hemorrhage (ICH)-induced white matter injury has not been well studied. The objective of this study was to examine the effect of zinc protoporphyrin (ZnPP) on white matter injury induced by ICH. This study was divided into two parts. In the first part, rats received either a needle insertion (sham) or 100 μl autologous blood into the right basal ganglia. The rats were euthanized at 1, 3, 7, 14, or 28 days later for myelin basic protein (MBP) measurement. In the second part, rats had intracerebral infusion of 100 μl autologous blood, and an intraperitoneal osmotic mini-pump was implanted immediately after ICH to deliver vehicle or ZnPP (1 nmol/h), a heme oxygenase inhibitor, for up to 14 days. Rats were euthanized at day 28 for MBP staining. The number of MBP-labeled fiber bundles and their area were determined. The time-course showed that the white matter was lost in the ipsilateral basal ganglia from day 1 to day 28 after ICH. The number of MBP-labeled bundles and their area were significantly lower 2 weeks after ICH compared with sham-operated rats (p < 0.05). Systemic treatment with ZnPP attenuated the loss of MBP-labeled bundles (p < 0.01) and area (p < 0.01). In conclusion, marked white matter injury occurs after ICH. ZnPP reduces white matter injury, suggesting a role of heme degradation products in ICH-induced white matter damage.

Minocycline Attenuates Iron-Induced Brain Injury

Iron plays an important role in brain injury after intracerebral hemorrhage (ICH). Our previous study found minocycline reduces iron overload after ICH. The present study examined the effects of minocycline on the subacute brain injury induced by iron. Rats had an intracaudate injection of 50 μl of saline, iron, or iron + minocycline. All the animals were euthanized at day 3. Rat brains were used for immunohistochemistry (n = 5-6 per each group) and Western blotting assay (n = 4). Brain swelling, blood-brain barrier (BBB) disruption, and iron-handling proteins were measured. We found that intracerebral injection of iron resulted in brain swelling, BBB disruption, and brain iron-handling protein upregulation (p < 0.05). The co-injection of minocycline with iron significantly reduced iron-induced brain swelling (n = 5, p < 0.01). Albumin, a marker of BBB disruption, was measured by Western blot analysis. Minocycline significantly decreased albumin protein levels in the ipsilateral basal ganglia (p < 0.01). Iron-handling protein levels in the brain, including ceruloplasmin and transferrin, were reduced in the minocycline co-injected animals. In conclusion, the present study suggests that minocycline attenuates brain swelling and BBB disruption via an iron-chelation mechanism.

Effect of Gender on Iron-induced Brain Injury in Low Aerobic Capacity Rats

Brain iron overload has a key role in brain injury after intracerebral hemorrhage (ICH). Low aerobic capacity is a risk factor for cardiovascular disease and our previous study demonstrated that ICH-induced brain injury is enhanced in rats with low aerobic capacity (low capacity runners; LCRs). We have found that ICH-induced injury is less in female rats compared with that in males. In the present study, we examined the effects of gender on iron-induced brain injury in rats with low aerobic capacity. Adult male and female LCR rats had an intracaudate injection of FeCl2 (50 μl 0.5 mM). T2 Magnetic resonance imaging was carried out at 24 h to determine brain swelling and T2 brain lesion volume. Albumin leakage, an indicator of blood-brain barrier (BBB) disruption, and heme oxygenase-1 (HO-1, a stress marker) levels were determined. Male LCR rats had more severe hemisphere swelling (difference of ipsilateral to contralateral hemisphere volume: 16.6 ± 4.1 vs 11.1 ± 2.6 % in females, p < 0.05) and larger T2 lesion volumes (120 ± 28 vs 87 ± 27 mm(3) in females, p < 0.05) after iron injection. Iron also resulted in more severe BBB disruption in the ipsilateral hemisphere of males (albumin levels: 7,717 ± 1,502 pixels in males vs 5,287 ± 1,342 pixels in females; p < 0.05). The immunoreactivity of HO-1 was also significantly higher in males than females (HO-1/β-actin: 1.31 ± 0.44 vs 1.03 ± 0.05, p < 0.05). Female LCR rats had less iron-induced brain swelling, smaller lesion volumes, and reduced BBB disruption and HO-1 upregulation compared with male LCR rats. This may contribute to the reduced ICH-induced brain injury found in females.

Effects of Gender and Estrogen Receptors on Iron-Induced Brain Edema Formation

Our previous studies have shown that female mice have less brain edema and better recovery in neurological deficits after intracerebral hemorrhage (ICH) and that 17β-estradiol treatment in male mice markedly reduces ICH-induced brain edema. In this study, we investigated the role of gender and the estrogen receptors (ERs) in iron-induced brain edema. There were three parts in this study: (1) either male or female mice received an injection of 10 μL FeCl2 (1 mM) into the right caudate; (2) females received an intracaudate injection of FeCl2 or saline with 1 μg of ICI 182,780 (antagonists of ERs) or vehicle; and (3) males were treated with the ER regulator tamoxifen (5 mg/kg subcutaneously) or vehicle 1 h after FeCl2 injection. Mice were euthanized 24 h later for brain edema determination. FeCl2 induced lower brain edema in females than in males. Co-injection of ICI 182,780 with FeCl2 aggravated iron-induced brain edema in female mice. ICI 182,780 itself did not induce brain edema at the dose of 1 μg. Tamoxifen treatment reduced FeCl2-induced brain edema in male mice. In conclusion, iron induced less brain edema in female mice than in males. ER modification can affect iron-induced brain edema.

Modulating the Immune Response Towards a Neuroregenerative Peri-injury Milieu After Cerebral Hemorrhage

Cerebral hemorrhages account for 15-20 % of stroke sub-types and have very poor prognoses. The mortality rate for cerebral hemorrhage patients is between 40 and 50 %, of which at least half of the deaths occur within the first 2 days, and 75 % of survivors are incapable of living independently after 1 year. Current emergency interventions involve lowering blood pressure and reducing intracranial pressure by controlled ventilations or, in the worst case scenarios, surgical intervention. Some hemostatic and coagulatherapeutic interventions are being investigated, although a few that were promising in experimental studies have failed in clinical trials. No significant immunomodulatory intervention, however, exists for clinical management of cerebral hemorrhage. The inflammatory response following cerebral hemorrhage is particularly harmful in the acute stage because blood-brain barrier disruption is amplified and surrounding tissue is destroyed by secreted proteases and reactive oxygen species from infiltrated leukocytes. In this review, we discuss both the destructive and regenerative roles the immune response play following cerebral hemorrhage and focus on microglia, macrophages, and T-lymphocytes as the primary agents directing the response. Microglia, macrophages, and T-lymphocytes each have sub-types that significantly influence the over-arching immune response towards either a pro-inflammatory, destructive, or an anti-inflammatory, regenerative, state. Both pre-clinical and clinical studies of cerebral hemorrhages that selectively target these immune cells are reviewed and we suggest immunomodulatory therapies that reduce inflammation, while augmenting neural repair, will improve overall cerebral hemorrhage outcomes.

Dimethyl fumarate confers neuroprotection by casein kinase 2 phosphorylation of Nrf2 in murine intracerebral hemorrhage

BACKGROUND AND PURPOSE

Edema formation, inflammation and increased blood-brain barrier permeability contribute to poor outcomes after intracerebral hemorrhage (ICH). This study examined the therapeutic effect of dimethyl fumarate (DMF), a fumaric acid ester that activates nuclear factor erythroid-2 related factor 2 (Nrf2) and Nrf2 heterodimerization effector protein musculo-aponeurotic fibrosarcoma-G (MAFG) in a murine ICH model.

METHODS

Male CD-1 mice (n=176) were subjected to intrastriatal infusion of bacterial collagenase (n=126), autologous blood (n=18) or sham surgery (n=32). Four (4) animals not subjected to ICH (naive) were also included in the study. After ICH, animals either received vehicle, dimethyl fumarate (10 mg or 100 mg/kg) or casein kinase 2 inhibitor (E)-3-(2,3,4,5-tetrabromophenyl)acrylic acid (TBCA). Thirty-two mice also received scrambled siRNA or MAFG siRNA 24h before ICH. Brain water content and neurological function were evaluated.

RESULTS

Dimethyl fumarate reduced Evans blue dye extravasation, decreased brain water content, and improved neurological deficits at 24 and 72 h after ICH. Casein kinase 2 inhibitor TBCA and MAFG siRNA prevented the effect of dimethyl fumarate on brain edema and neurological function. After ICH, ICAM-1 levels increased and casein kinase 2 levels decreased. Dimethyl fumarate reduced ICAM-1 but enhanced casein kinase 2 levels. Again, casein kinase 2 inhibitor TBCA and MAFG siRNA abolished the effect of dimethyl fumarate on ICAM-1 and casein kinase 2. Dimethyl fumarate preserved pNrf2 and MAFG expression in the nuclear lysate after ICH and the effect of dimethyl fumarate was abolished by casein kinase 2 inhibitor TBCA and MAFG siRNA. Dimethyl fumarate reduced microglia activation in peri-hematoma areas after ICH. The protective effect of dimethyl fumarate on brain edema and neurological function was also observed in a blood injection mouse model.

CONCLUSION

Dimethyl fumarate ameliorated inflammation, reduced blood-brain barrier permeability, and improved neurological outcomes by casein kinase 2 and Nrf2 signaling pathways after experimental ICH in mice.

Diffusion tensor imaging in hemorrhagic stroke

Diffusion tensor imaging (DTI) has evolved considerably over the last decade to now be knocking on the doors of wider clinical applications. There have been several efforts over the last decade to seek valuable and reliable application of DTI in different neurological disorders. The role of DTI in predicting outcomes in patients with brain tumors has been extensively studied and has become a fairly established clinical tool in this scenario. More recently DTI has been applied in mild traumatic brain injury to predict clinical outcomes based on DTI of the white matter tracts. The resolution of white matter fiber tractography based on DTI has improved over the years with increased magnet strength and better tractography post-processing. The role of DTI in hemorrhagic stroke has been studied preliminarily in the scientific literature. There is some evidence that DTI may be efficacious in predicting outcomes of motor function in animal models of intracranial hemorrhage. Only a handful of studies of DTI have been performed in subarachnoid hemorrhage or intraventricular hemorrhage scenarios. In this manuscript we will review the evolution of DTI, the existing evidence for its role in hemorrhagic stroke and discuss possible application of this non-invasive evaluation technique of human cerebral white matter tracts in the future.

MFGE8/Integrin β3 pathway alleviates apoptosis and inflammation in early brain injury after subarachnoid hemorrhage in rats

BACKGROUND

Milk fat globule-epidermal growth factor-factor 8(MFGE8)/Integrin β3 pathway was reported to be involved in reducing oxidative stress and early brain injury after subarachnoid hemorrhage (SAH). In the present study, the potential effects of MFGE8 and its receptor Integrin β3 in the inhibition of apoptosis and neuroinflammation in early brain injury after SAH were investigated.

METHODS

Ninety-five (95) male Sprague-Dawley rats were used. The SAH model was induced by endovascular perforation. Recombinant human MFGE8 (rhMFGE8), MFGE8 small interfering RNA (siRNA) and Integrin β3 siRNA were injected intracerebroventricularly. SAH grade, neurologic scores, Western blots and immunofluorescence were employed to study the mechanisms of MFGE8 and its receptor Integrin β3, as well as neurological outcome.

RESULTS

SAH induced significant neuronal apoptosis and inflammation and exhibited neurological dysfunction in rats. Knockdown endogenous MFGE8 with siRNA significantly increased the protein levels of cleaved caspase 3 and IL-1β, accompanied with more neurological deficits. rhMFGE8 significantly reduced neural cell death in cortex, decreased cleaved caspase 3 and IL-1β expressions, and improved neurological functions 24h after SAH. The anti-apoptosis and anti-inflammation effects of rhMFGE8 were abolished by Integrin β3 siRNA.

CONCLUSION

MFGE8 could alleviate neurologic damage in early brain injury after SAH via anti-inflammation and anti-apoptosis effects. MFGE8 may serve as a promising therapeutic target for future management of SAH patients.

Translational intracerebral hemorrhage: a need for transparent descriptions of fresh tissue sampling and preclinical model quality

For years, strategies have been proposed to improve translational success in stroke research by improving the quality of animal studies. However, articles that report preclinical intracerebral hemorrhage (ICH) studies continue to lack adequate qualitative and quantitative descriptions of fresh brain tissue collection. They also tend to lack transparency about animal model quality. We conducted a systematic review of 82 ICH research articles to determine the level of detail reported for brain tissue collection. We found that only 24 (29 %) reported the volume, weight, or thickness of tissue collected and a specific description of the anatomical location. Thus, up to 71 % of preclinical ICH research articles did not properly define how fresh specimens were collected for biochemical measurements. Such omissions may impede reproducibility of results between laboratories. Although existing criteria have improved the quality of preclinical stroke studies, ICH researchers need to identify specific guidelines and strategies to avoid pitfalls, minimize bias, and increase reproducibility in this field.

Deferoxamine reduces intracerebral hemorrhage-induced white matter damage in aged rats

Iron contributes to c-Jun N-terminal kinases (JNK) activation in young rats and white matter injury in piglets after intracerebral hemorrhage (ICH). In the present study, we examined the effect of deferoxamine on ICH-induced white matter injury and JNK activation and in aged rats. Male Fischer 344 rats (18months old) had either an intracaudate injection of 100μl of autologous blood or a needle insertion (sham). The rats were treated with deferoxamine or vehicle with different regimen (dosage, duration and time window). White matter injury and activation of JNK were examined. We found that a dose of DFX should be at more than 10mg/kg for a therapeutic duration more than 2days with a therapeutic time window of 12h to reduce ICH-induced white matter loss at 2months. ICH-induced white matter injury was associated with JNK activation. The protein levels of phosphorylated-JNK (P-JNK) were upregulated at day-1 after ICH and then gradually decreased. P-JNK immunoreactivity was mostly located in white matter bundles. ICH-induced JNK activation was reduced by DFX treatment. This study demonstrated that DFX can reduce ICH-induced JNK activation and white matter damage.