Deferoxamine-induced attenuation of brain edema and neurological deficits in a rat model of intracerebral hemorrhage

Deferoxamine Induces Autophagy Following Traumatic Brain Injury via TREM2 on Microglia

Previous studies have indicated that iron disorder, inflammation, and autophagy play an important role in traumatic brain injury (TBI). The triggering receptor expressed on myeloid cells 2 (TREM2), an immunoglobulin superfamily transmembrane receptor, is involved in inflammation. However, the role of TREM2 in modulating the microglia response in TBI has been rarely investigated. The present study aimed to investigate if the iron chelator deferoxamine (DFO) could ameliorate TBI through autophagy mediated by the TREM2. TBI was developed by the controlled cortical impact (CCI) mouse model and stretching of individual primary cortical microglia taken from the tissue of the rat brain. DFO was intraperitoneally used for intervention. Western blotting assay, qRT-PCR, TUNEL staining, immunofluorescence staining, confocal microscopy analysis, transmission electron microscopy, H&E staining, brain water content measurement, and the neurobehavioral assessments were performed. TREM2 expression was up-regulated in cortex of TBI mice model and in microglia stretching model, which was attenuated by DFO. After the mice were subjected to CCI, DFO treatment significantly up-regulated the protein levels of autophagy compared with the TBI group at 3 days and caused an increase of autophagic vacuoles. Treatment with DFO reduced TBI-induced cell apoptosis, cerebral edema, neuroinflammation, and motor function impairment in mice, at least partly via the mTOR signaling pathway that facilitates the TREM2 activity. The results indicated that the maintenance of iron homeostasis by DFO plays neuroprotection by modulating the inflammatory response to TBI through TREM2-mediated autophagy. This study suggested that TREM2-mediated autophagy might be a potential target for therapeutic intervention in TBI.

Ferroptosis: A double-edged sword

Ferroptosis represents a form of programmed cell death that is propelled by iron-dependent lipid peroxidation, thereby being distinguished by the prominent features of iron accumulation and lipid peroxidation. Ferroptosis has been implicated in numerous physiological and pathological phenomena, with mounting indications that it holds significant implications for cancer and other medical conditions. On one side, it demonstrates anti-cancer properties by triggering ferroptosis within malignant cells, and on the other hand, it damages normal cells causing other diseases. Therefore, in this paper, we propose to review the paradoxical regulation of ferroptosis in tumors and other diseases. First, we introduce the development history, concept and mechanism of ferroptosis. The second part focuses on the methods of inducing ferroptosis in tumors. The third section emphasizes the utilization of ferroptosis in different medical conditions and strategies to inhibit ferroptosis. The fourth part elucidates the key contradictions in the control of ferroptosis. Finally, potential research avenues in associated domains are suggested.

Hypothermia and temperature modulation for intracerebral hemorrhage (ICH): pathophysiology and translational applications

Background

Intracerebral hemorrhage (ICH) still poses a substantial challenge in clinical medicine because of the high morbidity and mortality rate that characterizes it. This review article expands into the complex pathophysiological processes underlying primary and secondary neuronal death following ICH. It explores the potential of therapeutic hypothermia as an intervention to mitigate these devastating effects.

Methods

A comprehensive literature review to gather relevant studies published between 2000 and 2023.

Discussion

Primary brain injury results from mechanical damage caused by the hematoma, leading to increased intracranial pressure and subsequent structural disruption. Secondary brain injury encompasses a cascade of events, including inflammation, oxidative stress, blood-brain barrier breakdown, cytotoxicity, and neuronal death. Initial surgical trials failed to demonstrate significant benefits, prompting a shift toward molecular mechanisms driving secondary brain injury as potential therapeutic targets. With promising preclinical outcomes, hypothermia has garnered attention, but clinical trials have yet to establish its definitive effectiveness. Localized hypothermia strategies are gaining interest due to their potential to minimize systemic complications and improve outcomes. Ongoing and forthcoming clinical trials seek to clarify the role of hypothermia in ICH management.

Conclusion

Therapeutic hypothermia offers a potential avenue for intervention by targeting the secondary injury mechanisms. The ongoing pursuit of optimized cooling protocols, localized cooling strategies, and rigorous clinical trials is crucial to unlocking the potential of hypothermia as a therapeutic tool for managing ICH and improving patient outcomes.

Deferoxamine Mitigates Ferroptosis and Inflammation in Hippocampal Neurons After Subarachnoid Hemorrhage by Activating the Nrf2/TXNRD1 Axis

Ferroptosis is a distinct peroxidation-driven form of cell death tightly involved in subarachnoid hemorrhage (SAH). This study delved into the mechanism of deferoxamine (DFO, an iron chelator) in SAH-induced ferroptosis and inflammation. SAH mouse models were established by endovascular perforation method and injected intraperitoneally with DFO, or intraventricularly injected with the Nrf2 pathway inhibitor ML385 before SAH, followed by detection of neurological function, blood-brain barrier (BBB) permeability, and brain water content. Apoptotic level of hippocampal neurons, symbolic changes of ferroptosis, and levels of pro-inflammatory cytokines were assessed using TUNEL staining, Western blotting, colorimetry, and ELISA. The localization and expression of nuclear factor-erythroid 2-related factor 2 (Nrf2) were detected. HT22 cells were exposed to Hemin as in vitro SAH models and treated with FIN56 to induce ferroptosis, followed by evaluation of the effects of DFO on FIN56-treated HT22 cells. The regulation of Nrf2 in thioredoxin reductase 1 (TXNRD1) was analyzed by co-immunoprecipitation and Western blotting. Moreover, HT22 cells were treated with DFO and ML385 to identify the role of DFO in the Nrf2/TXNRD1 axis. DFO extenuated brain injury, and ferroptosis and inflammation in hippocampal neurons of SAH mice. Nrf2 localized at the CA1 region of hippocampal neurons, and DFO stimulated nuclear translocation of Nrf2 protein in hippocampal neurons of SAH mice. Additionally, DFO inhibited ferroptosis and inflammatory responses in FIN56-induced HT22 cells. Nrf2 positively regulated TXNRD1 protein expression. Indeed, DFO alleviated FIN56-induced ferroptosis and inflammation via activation of the Nrf2/TXNRD1 axis. DFO alleviated neurological deficits, BBB disruption, brain edema, and brain injury in mice after SAH by inhibiting hippocampal neuron ferroptosis via the Nrf2/TXNRD1 axis. DFO ameliorates SAH-induced ferroptosis and inflammatory responses in hippocampal neurons by activating the Nrf2/TXNRD1 axis.

Common Mutation in the HFE Gene Modifies Recovery After Intracerebral Hemorrhage

BACKGROUND

Intracerebral hemorrhage (ICH) is characterized by bleeding into the brain parenchyma. During an ICH, iron released from the breakdown of hemoglobin creates a cytotoxic environment in the brain through increased oxidative stress. Interestingly, the loss of iron homeostasis is associated with the pathological process of other neurological diseases. However, we have previously shown that the H63D mutation in the homeostatic iron regulatory (HFE) gene, prevalent in 28% of the White population in the United States, acts as a disease modifier by limiting oxidative stress. The following study aims to examine the effects of the murine homolog, H67D HFE, on ICH.

METHODS

An autologous blood infusion model was utilized to create an ICH in the right striatum of H67D and wild-type mice. The motor recovery of each animal was assessed by rotarod. Neurodegeneration was measured using fluorojade-B and mitochondrial damage was assessed by immunofluorescent numbers of CytC+ (cytochrome C) neurons and CytC+ astrocytes. Finally, the molecular antioxidant response to ICH was quantified by measuring Nrf2 (nuclear factor-erythroid 2 related factor), GPX4 (glutathione peroxidase 4), and FTH1 (H-ferritin) levels in the ICH-affected and nonaffected hemispheres via immunoblotting.

RESULTS

At 3 days post-ICH, H67D mice demonstrated enhanced performance on rotarod compared with wild-type animals despite no differences in lesion size. Additionally, H67D mice displayed higher levels of Nrf2, GPX4, and FTH1 in the ICH-affected hemisphere; however, these levels were not different in the contralateral, non-ICH-affected hemisphere. Furthermore, H67D mice showed decreased degenerated neurons, CytC+ Neurons, and CytC+ astrocytes in the perihematomal area.

CONCLUSIONS

Our data suggest that the H67D mutation induces a robust antioxidant response 3 days following ICH through Nrf2, GPX4, and FTH1 activation. This activation could explain the decrease in degenerated neurons, CytC+ neurons, and CytC+ astrocytes in the perihematomal region, leading to the improved motor recovery. Based on this study, further investigation into the mechanisms of this neuroprotective response and the effects of the H63D HFE mutation in a population of patients with ICH is warranted.

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.

A case of intravenous iron administration resulting in cerebral edema expansion

BACKGROUND

Iron plays an important role in the development of perihematomal edema (PHE) in the setting of intracerebral hemorrhage (ICH). Cerebral iron is increased via direct hemoglobin release in ICH, and several studies have investigated the use of iron-chelating agents to mitigate its toxicity. However, the effect of systemic iron administration, corroborating the reverse concept, has never been investigated or reported clinically. We report the first case of systemic iron administration in the setting of hemorrhagic traumatic brain injury (TBI).

CASE PRESENTATION

A 46-year-old woman was admitted to the hospital with acute moderate-to-severe TBI. Her head computed tomography (CT) scan showed bifrontal hemorrhagic contusions with mild PHE. She was started on hypertonic saline 3% continuous infusion and her condition remained stable initially. She was found to be anemic and was given intravenous iron sucrose. Shortly after iron administration, her mental status declined, and left pupil became dilated and sluggish. Repeat CT demonstrated significantly worsening PHE. This prompted maximum hyperosmolar therapy and external ventricular drain (EVD) placement which both were weaned off slowly due to liable ICPs. She was discharged home after a 25-day hospital stay.

CONCLUSIONS

We believe this is the first report of exacerbating PHE accompanied by clinical decline after intravenous iron administration in the setting of acute hemorrhagic brain contusions. Though the effects of systemic iron administration on brain edema and the treatments targeting cerebral iron are poorly understood, the administration of systemic iron in acute TBI seems to be detrimental. More research is needed to address iron toxicity in TBI. Our case adds to the growing evidence for such a pathway in the treatment of ICH and TBI.

Elucidating the progress and impact of ferroptosis in hemorrhagic stroke

Hemorrhagic stroke is a devastating cerebrovascular disease with high morbidity and mortality, for which effective therapies are currently unavailable. Based on different bleeding sites, hemorrhagic stroke can be generally divided into intracerebral hemorrhage (ICH) and subarachnoid hemorrhage (SAH), whose pathogenesis share some similarity. Ferroptosis is a recently defined programmed cell deaths (PCDs), which is a critical supplement to the hypothesis on the mechanism of nervous system injury after hemorrhagic stroke. Ferroptosis is characterized by distinctive morphological changes of mitochondria and iron-dependent accumulation of lipid peroxides. Moreover, scientists have successfully demonstrated the involvement of ferroptosis in animal models of ICH and SAH, indicating that ferroptosis is a promising target for hemorrhagic stroke therapy. However, the studies on ferroptosis still faces a serious of technical and theoretical challenges. This review systematically elaborates the role of ferroptosis in the pathogenesis of hemorrhagic stroke and puts forward some opinions on the dilemma of ferroptosis research.

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.

Chaetomadramines A-E, a class of siderophores with potent neuroprotective activity from the fungus Chaetomium madrasense cib-1

Five hydroxamate siderophores, chaetomadramines A-E (1-5), along with seven known compounds were isolated from the fermented rice culture of the fungus Chaetomium madrasense cib-1. Compounds 1-5 were structurally elucidated on the basis of spectroscopic data, which were a group of unusual hydroxamate siderophores, bearing a long fatty acyl on the α-NH₂ of the N^δ-hydroxylated ornithine. Compounds 2-5 were new. The structural elucidation and spectroscopic data of 1 were reported for the first time. Compounds 2-4 significantly improved the survival rates of PC12 cells in the neuroprotective activity assay at the concentration of 40 μM.

Role of Ferroptosis in Stroke

Stroke is a common and serious nervous system disease caused by the rupture or blockage of the cardiovascular system. It causes millions of deaths and disabilities every year, which is a huge burden on humanity. It may be induced by thrombosis, hypertension, hyperlipidemia, hyperglycemia, smoking, advanced age and so on. According to different causes, stroke can be generally divided into hemorrhagic stroke and ischemic stroke, whose pathogenesis and treatment are quite different. Ferroptosis is a new type of cell death first defined in 2012, which is characterized by non-apoptotic, iron-dependent, and over-accumulated lipid peroxides. Excess lipid reactive oxygen species produced during ferroptosis eventually leads to oxidative cell death. Ferroptosis has been shown to occur and play an important role in tumors, neurological diseases, kidney injury, and ischemia-reperfusion injury. Ferroptosis is also closely related to the pathogenesis of stroke. Moreover, scientists have successfully intervened in the process of stroke in animal models by regulating ferroptosis, indicating that ferroptosis is a new potential target for the treatment of stroke. This paper systematically summarizes the involvement and role of ferroptosis in the pathogenesis of stroke and predicts the potential of ferroptosis in the treatment of stroke. Ferroptosis in stroke. Stroke induces iron overload and lipid metabolism disorders. Elevated iron catalyzes lipid peroxidation and eventually triggers ferroptosis. Conversely, the GSH/GPX4 pathway, as well as CoQ10, Fer-1, and Lip-1, inhibits lipid peroxidation and, thus, alleviates ferroptosis. GSH glutathione; GPX4 glutathione peroxidase 4; CoQ10 coenzyme Q10; Lip-1 liproxstatin-1; Fer-1 ferostatin-1.

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.

Therapeutic strategies for intracerebral hemorrhage

Stroke is the second highest cause of death globally, with an increasing incidence in developing countries. Intracerebral hemorrhage (ICH) accounts for 10-15% of all strokes. ICH is associated with poor neurological outcomes and high mortality due to the combination of primary and secondary injury. Fortunately, experimental therapies are available that may improve functional outcomes in patients with ICH. These therapies targeting secondary brain injury have attracted substantial attention in their translational potential. Here, we summarize recent advances in therapeutic strategies and directions for ICH and discuss the barriers and issues that need to be overcome to improve ICH prognosis.

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).

Potential role of IGF-1/GLP-1 signaling activation in intracerebral hemorrhage

IGF-1 and GLP-1 receptors are essential in all tissues, facilitating defense by upregulating anabolic processes. They are abundantly distributed throughout the central nervous system, promoting neuronal proliferation, survival, and differentiation. IGF-1/GLP-1 is a growth factor that stimulates neurons' development, reorganization, myelination, and survival. In primary and secondary brain injury, the IGF-1/GLP-1 receptors are impaired, resulting in further neuro complications such as cerebral tissue degradation, neuroinflammation, oxidative stress, and atrophy. Intracerebral hemorrhage (ICH) is a severe condition caused by a stroke for which there is currently no effective treatment. While some pre-clinical studies and medications are being developed as symptomatic therapies in clinical trials, there are specific pharmacological implications for improving post-operative conditions in patients with intensive treatment. Identifying the underlying molecular process and recognizing the worsening situation can assist researchers in developing effective therapeutic solutions to prevent post-hemorrhagic symptoms and the associated neural dysfunctions. As a result, in the current review, we have addressed the manifestations of the disease that are aggravated by the downregulation of IGF-1 and GLP-1 receptors, which can lead to ICH or other neurodegenerative disorders. Our review summarizes that IGF-1/GLP-1 activators may be useful for treating ICH and its related neurodegeneration.

Ferroptosis—A Novel Mechanism With Multifaceted Actions on Stroke

As a neurological disease with high morbidity, disability, and mortality, the pathological mechanism underlying stroke involves complex processes such as neuroinflammation, oxidative stress, apoptosis, autophagy, and excitotoxicity; but the related research on these molecular mechanisms has not been effectively applied in clinical practice. As a form of iron-dependent regulated cell death, ferroptosis was first discovered in the pathological process of cancer, but recent studies have shown that ferroptosis is closely related to the onset and development of stroke. Therefore, a deeper understanding of the relationship between ferroptosis and stroke may lead to more effective treatment strategies. Herein, we reviewed the mechanism(s) underlying the onset of ferroptosis in stroke, the potential role of ferroptosis in stroke, and the crosstalk between ferroptosis and other pathological mechanisms. This will further deepen our understanding of ferroptosis and provide new approaches to the treatment of stroke.

Oxidative Stress Following Intracerebral Hemorrhage: From Molecular Mechanisms to Therapeutic Targets

Intracerebral hemorrhage (ICH) is a highly fatal disease with mortality rate of approximately 50%. Oxidative stress (OS) is a prominent cause of brain injury in ICH. Important sources of reactive oxygen species after hemorrhage are mitochondria dysfunction, degradated products of erythrocytes, excitotoxic glutamate, activated microglia and infiltrated neutrophils. OS harms the central nervous system after ICH mainly through impacting inflammation, killing brain cells and exacerbating damage of the blood brain barrier. This review discusses the sources and the possible molecular mechanisms of OS in producing brain injury in ICH, and anti-OS strategies to ameliorate the devastation of ICH.

Revisiting Minocycline in Intracerebral Hemorrhage: Mechanisms and Clinical Translation

Intracerebral hemorrhage (ICH) is an important subtype of stroke with an unsatisfactory prognosis of high mortality and disability. Although many pre-clinical studies and clinical trials have been performed in the past decades, effective therapy that meaningfully improve prognosis and outcomes of ICH patients is still lacking. An active area of research is towards alleviating secondary brain injury after ICH through neuroprotective pharmaceuticals and in which minocycline is a promising candidate. Here, we will first discuss new insights into the protective mechanisms of minocycline for ICH including reducing iron-related toxicity, maintenance of blood-brain barrier, and alleviating different types of cell death from preclinical data, then consider its shortcomings. Finally, we will review clinical trial perspectives for minocycline in ICH. We hope that this summary and discussion about updated information on minocycline as a viable treatment for ICH can facilitate further investigations.

Minimally Invasive Surgery for ICH Evacuation Combined With Deferoxamine Treatment Increased Perihematomal Claudin-5 and ZO-1 Expression Levels and Decreased BBB Permeability in Rabbits

Objective

To investigate the role of minimally invasive surgery (MIS) in intracerebral hemorrhage (ICH) evacuation combined with deferoxamine (DFX) treatment on perihematomal tight junction protein (claudin-5 and ZO-1) expression levels and blood-brain barrier (BBB) permeability in rabbits.

Methods

We randomly assigned 65 male rabbits (weight: 1.9–2.6 kg) to a normal control group (NC group, 13 rabbits), hemorrhage model group (HM group, 13), DFX treatment group (DFX group, 13 rabbits), MIS group (MIS group, 13 rabbits), or MIS combined with DFX treatment group (MIS + DFX group, 13 rabbits). ICH was established in all of the groups except the NC group. MIS was performed to evacuate the hematoma 6 h after the ICH model was created in the MIS and MIS + DFX groups. The DFX and MIS + DFX groups were treated with DFX (100 mg/kg, dissolved in 2 mL of 0.9% saline solution, administered intramuscularly) at 2 h, and then every 12 h for 7 d. The same dose of 0.9% saline solution was administered to the NC, HM, and MIS groups at the same time points. Sixty-five rabbits were divided into 5 groups, and 13 rabbits in each group. Neurological deficit (i.e., Purdy's score) was recorded in all rabbits before euthanasia (N total = 65). In each group, 2 rabbits were used for iron concentration measurement (N total = 10), 2 rabbits were used for brain water content measurement (N total = 10), 3 rabbits were used for BBB permeability measurement (N total = 15), 3 rabbits were used for claudin-5, ZO-1 expression detection by Western Blotting (N total = 15), and 3 rabbits were used for claudin-5, ZO-1 mRNA detection by real-time PCR (N total = 15). On day 7, the rabbits were sacrificed and the perihematomal brain tissue was harvested to test the iron concentration, brain water content (BWC), tight junction proteins (claudin-5 and ZO-1) expression, and BBB permeability.

Results

Purdy's score, iron concentration, and BWC were lower in the MIS and MIS + DFX groups compared to the HM and DFX groups. The MIS + DFX group showed a significant decrease in these indicators. The use of MIS to evacuate the hematoma led to increased expression levels of claudin-5 and ZO-1, as well as decreased BBB permeability. The MIS + DFX group exhibited a remarkable increase in claudin-5 and ZO-1 expression levels and a significant decrease in BBB permeability.

Conclusions

MIS combined with DFX treatment could increase the expression levels of perihematomal tight junction proteins (claudin-5 and ZO-1) expression, reduce BBB permeability, and improve the neurological function. MIS combined with DFX treatment may also prevent secondary brain damage following ICH.

Inhibition of HIF-1α-AQP4 axis ameliorates brain edema and neurological functional deficits in a rat controlled cortical injury (CCI) model

Traumatic brain injury (TBI) is an important cause of death in young adults and children. Till now, the treatment of TBI in the short- and long-term complications is still a challenge. Our previous evidence implied aquaporin 4 (AQP4) and hypoxia inducible factor-1α (HIF-1α) might be potential targets for TBI. In this study, we explored the roles of AQP4 and HIF-1α on brain edema formation, neuronal damage and neurological functional deficits after TBI using the controlled cortical injury (CCI) model. The adult male Sprague Dawley rats were randomly divided into sham and TBI group, the latter group was further divided into neutralized-AQP4 antibody group, 2-methoxyestradiol (2-ME2) group, and their corresponding control, IgG and isotonic saline groups, respectively. Brain edema was examined by water content. Hippocampal neuronal injury was assessed by neuron loss and neuronal skeleton related protein expressions. Spatial learning and memory deficits were evaluated by Morris water maze test and memory-related proteins were detected by western blot. Our data showed that increased AQP4 protein level was closely correlated with severity of brain edema after TBI. Compared with that in the control group, both blockage of AQP4 with neutralized-AQP4 antibody and inhibition of HIF-1α with 2-ME2 for one-time treatment within 30-60 min post TBI significantly ameliorated brain edema on the 1st day post-TBI, and markedly alleviated hippocampal neuron loss and spatial learning and memory deficits on the 21st day post-TBI. In summary, our preliminary study revealed the short-term and long-term benefits of targeting HIF-1α-AQP4 axis after TBI, which may provide new clues for the selection of potential therapeutic targets for TBI in clinical practice.

Iron toxicity in intracerebral hemorrhage: Physiopathological and therapeutic implications

Intracerebral hemorrhage (ICH)-induced brain injury is a continuous pathological process that involves the deterioration of neurological functions, such as sensory, cognitive or motor functions. Cytotoxic byproducts of red blood cell lysis, especially free iron, appear to be a significant pathophysiologic mechanism leading to ICH-induced injury. Free iron has a crucial role in secondary brain injury after ICH. Chelating iron may attenuate iron-induced neurotoxicity and may be developed as a therapeutic candidate for ICH treatment. In this review, we focused on the potential role of iron toxicity in ICH-induced injury and iron chelation therapy in the management of ICH. It will hopefully advance our understanding of the pathogenesis of ICH and lead to new approaches for treatment.

High Serum DNA and RNA Oxidative Damage in Non-surviving Patients with Spontaneous Intracerebral Hemorrhage

PURPOSE

One study found higher leukocytes 8-hydroxy-2'-deoxyguanosine (8-OHdG) levels in patients with spontaneous intracerebral hemorrhage (ICH) than in healthy subjects due to the oxidation of guanosine from deoxyribonucleic acid (DNA). The objective of this study was to determine whether there is an association between oxidative damage of serum DNA and ribonucleic acid (RNA) and mortality in patients with ICH.

METHODS

In this observational and prospective study, patients with severe supratentorial ICH (defined as Glasgow Coma Scale < 9) were included from six Intensive Care Units of Spanish hospitals. At the time of severe ICH diagnosis, concentrations in serum of malondialdehyde (as lipid peroxidation biomarker) and of the three oxidized guanine species (OGS) (8-hydroxyguanosine from RNA, 8-hydroxyguanine from DNA or RNA, and 8-OHdG from DNA) were determined. Thirty-day mortality was considered the end-point study.

RESULTS

Serum levels of OGS (p < 0.001) and malondialdehyde (p = 0.002) were higher in non-surviving (n = 46) than in surviving patients (n = 54). There was an association of serum OGS levels with serum malondialdehyde levels (rho = 0.36; p = 0.001) and 30-day mortality (OR = 1.568; 95% CI 1.183-2.078; p = 0.002).

CONCLUSIONS

The novel and most important finding of our study was that serum OGS levels in ICH patients are associated with mortality.

Targeting Pro-Oxidant Iron with Deferoxamine as a Treatment for Ischemic Stroke: Safety and Optimal Dose Selection in a Randomized Clinical Trial

A role of iron as a target to prevent stroke-induced neurodegeneration has been recently revisited due to new evidence showing that ferroptosis inhibitors are protective in experimental ischemic stroke and might be therapeutic in other neurodegenerative brain pathologies. Ferroptosis is a new form of programmed cell death attributed to an overwhelming lipidic peroxidation due to excessive free iron and reactive oxygen species (ROS). This study aims to evaluate the safety and tolerability and to explore the therapeutic efficacy of the iron chelator and antioxidant deferoxamine mesylate (DFO) in ischemic stroke patients. Administration of placebo or a single DFO bolus followed by a 72 h continuous infusion of three escalating doses was initiated during the tPA infusion, and the impact on blood transferrin iron was determined. Primary endpoint was safety and tolerability, and secondary endpoint was good clinical outcome (clinicalTrials.gov NCT00777140). DFO was found safe as adverse effects were not different between placebo and DFO arms. DFO (40-60 mg/Kg/day) reduced the iron saturation of blood transferrin. A trend to efficacy was observed in patients with moderate-severe ischemic stroke (NIHSS > 7) treated with DFO 40-60 mg/Kg/day. A good outcome was observed at day 90 in 31% of placebo vs. 50-58% of the 40-60 mg/Kg/day DFO-treated patients.

Neuroprotective Therapies for Spontaneous Intracerebral Hemorrhage

Patients who survive the initial ictus of spontaneous intracerebral hemorrhage (ICH) remain vulnerable to subsequent injury of the perilesional parenchyma by molecular and cellular responses to the hematoma. Secondary brain injury after ICH, which contributes to long-term functional impairment and mortality, has emerged as an attractive therapeutic target. This review summarizes preclinical and clinical evidence for neuroprotective therapies targeting secondary injury pathways following ICH. A focus on therapies with pleiotropic antiinflammatory effects that target thrombin-mediated chemotaxis and inflammatory cell migration has led to studies investigating statins, anticholinergics, sphingosine-1-phosphate receptor modulators, peroxisome proliferator activated receptor gamma agonists, and magnesium. Attempts to modulate ICH-induced blood-brain barrier breakdown and perihematomal edema formation has prompted studies of nonsteroidal antiinflammatory agents, matrix metalloproteinase inhibitors, and complement inhibitors. Iron chelators, such as deferoxamine and albumin, have been used to reduce the free radical injury that ensues from erythrocyte lysis. Stem cell transplantation has been assessed for its potential to enhance subacute neurogenesis and functional recovery. Despite promising preclinical results of numerous agents, their outcomes have not yet translated into positive clinical trials in patients with ICH. Further studies are necessary to improve our understanding of the molecular events that promote damage and inflammation of the perihematomal parenchyma after ICH. Elucidating the temporal and pathophysiologic features of this secondary brain injury could enhance the clinical efficacy of neuroprotective therapies for ICH.

The combination of deferoxamine and minocycline strengthens neuroprotective effect on acute intracerebral hemorrhage in rats

Objectives: Intracerebral hemorrhage (ICH) is a devastating type of strokes that carries high mortality rates, but effective therapeutic options are still lacking. Here, the adult rat model of ICH was used to investigate the efficacy of a combinational therapy of deferoxamine (DFX) and minocycline.Methods: The ICH was induced by stereotaxic infusion of collagenase into striatum of adult rats. After the induction of ICH, rats were treated with intraperitoneal injection of deferoxamine (50 mg/kg), minocycline (45 mg/kg), or both agents, at 2 hours after ICH and then every 12 hours for up to 3 days. The vehicle group were treated with phosphate-buffered saline (PBS) only. Rats were killed at 1, 2, and 3 day(s) for examination of iron deposition, neuronal death, neurological deficits, the area of brain damage, activation of microglia/macrophages.Results: Our data revealed that the systemic administration of DFX and/or minocycline decreased iron accumulation. And immunofluorescence staining results indicated that drug-treated group significantly decreased the neuronal degeneration, the number of activated microglia/macrophages and the amount of cell death after ICH. In addition, neurological deficits caused by ICH were improved in the presence of DFX and/or minocycline compare with vehicle group. Furthermore, the combination treatment showed better effects in neuroprotection and anti-inflammation when compared to the monotherapy groups.Conclusions: The combination therapy significantly reduces the number of neuronal deaths, suppresses of the activation of microglia/macrophages, decreases iron accumulation in the area around the hematoma, lessening the brain damage area, and improving neurological deficits in 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.

Hepcidin attenuates the iron-mediated secondary neuronal injury after intracerebral hemorrhage in rats

Iron plays a key role in secondary neuronal injury after intracerebral hemorrhage (ICH), and hepcidin is able to reduce brain iron in iron-overloaded rats by down-regulating iron transport proteins including ferroportin 1 and transferrin receptor 1. These led us to hypothesize that hepcidin might reduce iron-mediated neurotoxicity by inhibiting iron accumulation in ICH brain. Here, we examined effects of Ad-hepcidin (hepcidin expression adenovirus) on the nonheme iron contents, expression of hepcidin, ferritin and iron transport proteins, neuronal cell survival, water contents in the brain and/or cerebrospinal fluid (CSF), and ICH-induced apoptosis, neurological deficit by RT-PCR, Western blot analysis, NeuN Immunofluorescence, TUNEL, Fluoro-Jade B staining, behavioral performance and Morris water-maze tests in 510 rats. We demonstrated that hepcidin could significantly suppress the ICH-induced increase in iron and ferritin in brain tissues and CSF by inhibiting expression of iron transport proteins, increase neuronal survival by attenuating ICH-induced apoptosis, reactive oxygen species, neurodegeneration and brain edema, as well as effectively improve ICH-induced behavioral and cognitive deficit in rats. The findings collectively showed that hepcidin could effectively attenuate iron-mediated secondary neuronal injury after ICH in rats. This naturally existing protein can potentially be developed into a therapeutic drug for the treatment of ICH patients.

The role of complement in brain injury following intracerebral hemorrhage: A review

Intracerebral hemorrhage (ICH) is a significant cause of death and disability and current treatment is limited to supportive measures to reduce brain edema and secondary hematoma expansion. Current evidence suggests that the complement cascade is activated early after hemorrhage and contributes to brain edema/injury in multiple ways. The aim of this review is to summarize the most recent literature about the role of the complement cascade after ICH. Primary literature demonstrating complement mediated brain edema and neurologic injury through the membrane attack complex (MAC) as well as C3a and C5a are reviewed. Further, attenuation of brain edema and improved functional outcomes are demonstrated after inhibition of specific components of the complement cascade. Conversely, complement also plays a significant role in neurologic recovery after ICH and in other neurologic disorders. We conclude that the role of complement after ICH is complex. Understanding the role of complement after ICH is essential and may elucidate possible interventions to reduce brain edema and injury.

Role of ferroptosis in neurological diseases

Ferroptosis is a newly identified form of nonapoptotic regulated cell death (RCD) characterized by iron-dependent accumulation of lipid peroxides which leads to oxidative stress and cell death. Recent studies have indicated that ferroptosis plays an essential role in the pathology of neurological diseases, such as intracerebral hemorrhage, ischemic stroke, epilepsy, neurodegenerative diseases, traumatic brain injury and brain cancer. This review focuses on the latest researches on the relationship of ferroptosis with nervous system diseases, highlighting the ferroptosis-based mechanisms, and elaborating the new perspective therapeutic targets of neurological disorders.

Association of Brain Iron Overload With Brain Edema and Brain Atrophy After Intracerebral Hemorrhage

Objective: This study evaluated iron overload after intracerebral hemorrhage (ICH) using ESWAN sequences. Methods: This single-center prospective observational cohort study enrolled supratentorial ICH patients. MRI was obtained with a 3.0-T scanner at day 1, day 14, day 30, and follow-up (300 days or later). R2* mapping was generated based on the ESWAN. R2* value of the ipsilateral side represented iron deposition, and the R2* value of the contralateral side served as control. R2* value was adjusted by volume and used to assess total iron overload. Brain edema was measured on T2 FLAIR-weighted images. Brain atrophy was calculated as the contralateral hemisphere volume minus the injured hemisphere volume. Results: Twnety-seven patients with a spontaneous supratentorial ICH were included in this analysis. The ipsilateral R2* value was 40.27 ± 11.62, 41.92 ± 13.56, and 60.89 ± 14.09 at days 1, 14, and 30, respectively. The R2* value was significantly higher in the ICH side than the contralateral side (p < 0.01). Increased R2* value was seen on day 30 compared to day 14 (p < 0.01). The R2* value showed logistic decay with the distance to the hematoma margin (p < 0.01). Brain edema at day 14 and brain atrophy at follow-up correlated with R2* value adjusted by volume at day 14 (p < 0.01). Conclusions: After ICH, the iron deposition in the perihematomal region was progressively increased during the first month. R2* value adjusted by volume predicted acute brain edema and chronic brain atrophy.

Iron chelators for acute stroke

BACKGROUND

Stroke is the second leading cause of death and a major cause of morbidity worldwide. Retrospective clinical and animal studies have demonstrated neuroprotective effects of iron chelators in people with haemorrhagic or ischaemic stroke. This is the first update of the original Cochrane Review published in 2012.

OBJECTIVES

To evaluate the effectiveness and safety of iron-chelating drugs in people with acute stroke.

SEARCH METHODS

We searched the Cochrane Stroke Group Trials Register (2 September 2019), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2019, Issue 9; 2 September 2019), MEDLINE Ovid (2 September 2019), Embase Ovid (2 September 2019), and Science Citation Index (2 September 2019). We also searched ongoing trials registers.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) of iron chelators versus no iron chelators or placebo for the treatment of acute stroke, including subarachnoid haemorrhage.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened the search results. We obtained the full texts of potentially relevant studies and evaluated them for eligibility. We assessed risk of bias using the Cochrane 'Risk of bias' tool, and the certainty of evidence using the GRADE approach.

MAIN RESULTS

Two RCTs (333 participants) were eligible for inclusion; both compared the iron-chelating agent deferoxamine against placebo. Both studies evaluated participants with spontaneous intracerebral haemorrhage. We assessed one study to have a low risk of bias; the other study had potential sources of bias. The limited and heterogeneous data did not allow for meta-analysis of the outcome parameters. The evidence suggests that administration of deferoxamine may result in little to no difference in deaths (8% in placebo vs 8% in deferoxamine at 180 days; 1 RCT, 291 participants; low-certainty evidence). These RCTs suggest that there may be little to no difference in good functional outcome (modified Rankin Scale score 0 to 2) between groups at 30, 90 and 180 days (placebo vs deferoxamine: 67% vs 57% at 30 days and 36% vs 45% at 180 days; 2 RCTs, 333 participants; low-certainty evidence). One RCT suggests that administration of deferoxamine may not increase the number of serious adverse events or deaths (placebo vs deferoxamine: 33% vs 27% at 180 days; risk ratio 0.81, 95 % confidence interval 0.57 to 1.16; 1 RCT, 291 participants; low-certainty evidence). No data were available on any deaths within the treatment period. Deferoxamine may result in little to no difference in the evolution of National Institute of Health Stroke Scale scores from baseline to 90 days (placebo vs deferoxamine: 13 to 4 vs 13 to 3; P = 0.37; 2 RCTs, 333 participants; low-certainty evidence). Deferoxamine may slightly reduce relative oedema surrounding intracerebral haemorrhage at 15 days (placebo vs deferoxamine: 1.91 vs 10.26; P = 0.042; 2 RCTs, 333 participants; low-certainty evidence). Neither study reported quality of life.

AUTHORS' CONCLUSIONS

We identified two eligible RCTs for assessment. We could not demonstrate any benefit for the use of iron chelators in spontaneous intracerebral haemorrhage. The added value of iron-chelating therapy in people with ischaemic stroke or subarachnoid haemorrhage remains unknown.

High serum levels of TAC and early mortality in patients with spontaneous intracerebral haemorrhage

OBJECTIVE

Oxidation contributes to secondary brain injury after spontaneous intracerebral haemorrhage (SIH). One study found lower levels of total antioxidant capacity (TAC) in the blood in patients with SIH than in healthy subjects. However, there are no data on blood TAC levels and survival in patients with SIH. Therefore, the objective of our study was to determine if an association exists between serum TAC levels and mortality in patients with SIH.

METHODS

We included patients with severe supratentorial SIH. We considered severe when Glasgow Coma Scale (GCS) < 9. Patients from 6 Spanish hospitals were included in this observational and prospective study. Serum TAC levels at days 1, 4 and 8 of SIH were determined. Thirty-day mortality was our end-point study.

RESULTS

Non-surviving patients compared with surviving patients showed higher serum TAC levels at day 1 (p < 0.001), 4 (p < 0.001) and 8 (p = 0.001). An area under the curve was found for the prediction of 30-day mortality by serum TAC levels of 0.92 (95% CI = 0.85-96%; p < 0.001). Multiple logistic regression analysis showed an association of serum TAC levels with 30-day mortality (odds ratio = 16.513; 95% CI = 2.548-107.015; p = 0.003) controlling for midline shift, glycemia, early evacuation of SIH, intracerebral haemorrhage (ICH) score, age and volume of SIH.

CONCLUSIONS

The new findings of this study are that serum TAC levels are higher in non-surviving than in surviving patients, and that they are associated with mortality and could be used to predict mortality.

Ferroptosis in Acute Central Nervous System Injuries: The Future Direction?

Acute central nervous system (CNS) injuries, such as stroke, traumatic brain injury (TBI), and spinal cord injury (SCI) present a grave health care challenge worldwide due to high morbidity and mortality, as well as limited clinical therapeutic strategies. Established literature has shown that oxidative stress (OS), inflammation, excitotoxicity, and apoptosis play important roles in the pathophysiological processes of acute CNS injuries. Recently, there have been many studies on the topic of ferroptosis, a form of regulated cell death characterized by the accumulation of iron-dependent lipid peroxidation. Some studies have revealed an emerging connection between acute CNS injuries and ferroptosis. Ferroptosis, induced by the abnormal metabolism of lipids, glutathione (GSH), and iron, can accelerate acute CNS injuries. However, pharmaceutical agents, such as iron chelators, ferrostatin-1 (Fer-1), and liproxstatin-1 (Lip-1), can inhibit ferroptosis and may have neuroprotective effects after acute CNS injuries. However, the specific mechanisms underlying this connection has not yet been clearly elucidated. In this paper, we discuss the general mechanisms of ferroptosis and its role in stroke, TBI, and SCI. We also summarize ferroptosis-related drugs and highlight the potential therapeutic strategies in treating various acute CNS injuries. Additionally, this paper suggests a testable hypothesis that ferroptosis may be a novel direction for further research of acute CNS injuries by providing corresponding evidence.

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.

The Mitochondria-Derived Peptide Humanin Improves Recovery from Intracerebral Hemorrhage: Implication of Mitochondria Transfer and Microglia Phenotype Change

Astrocytes are an integral component of the neurovascular unit where they act as homeostatic regulators, especially after brain injuries, such as stroke. One process by which astrocytes modulate homeostasis is the release of functional mitochondria (Mt) that are taken up by other cells to improve their function. However, the mechanisms underlying the beneficial effect of Mt transfer are unclear and likely multifactorial. Using a cell culture system, we established that astrocytes release both intact Mt and humanin (HN), a small bioactive peptide normally transcribed from the Mt genome. Further experiments revealed that astrocyte-secreted Mt enter microglia, where they induce HN expression. Similar to the effect of HN alone, incorporation of Mt by microglia (1) upregulated expression of the transcription factor peroxisome proliferator-activated receptor gamma and its target genes (including mitochondrial superoxide dismutase), (2) enhanced phagocytic activity toward red blood cells (an in vitro model of hematoma clearance after intracerebral hemorrhage [ICH]), and (3) reduced proinflammatory responses. ICH induction in male mice caused profound HN loss in the affected hemisphere. Intravenously administered HN penetrated perihematoma brain tissue, reduced neurological deficits, and improved hematoma clearance, a function that normally requires microglia/macrophages. This study suggests that astrocytic Mt-derived HN could act as a beneficial secretory factor, including when transported within Mt to microglia, where it promotes a phagocytic/reparative phenotype. These findings also indicate that restoring HN levels in the injured brain could represent a translational target for ICH. These favorable biological responses to HN warrant studies on HN as therapeutic target for ICH.SIGNIFICANCE STATEMENT Astrocytes are critical for maintaining brain homeostasis. Here, we demonstrate that astrocytes secrete mitochondria (Mt) and the Mt-genome-encoded, small bioactive peptide humanin (HN). Mt incorporate into microglia, and both Mt and HN promote a "reparative" microglia phenotype characterized by enhanced phagocytosis and reduced proinflammatory responses. Treatment with HN improved outcomes in an animal model of intracerebral hemorrhage, suggesting that this process could have biological relevance to stroke pathogenesis.

Intracerebral Hemorrhage: Blood Components and Neurotoxicity

Intracerebral hemorrhage (ICH) is a subtype of stroke which is associated with the highest mortality and morbidity rates of all strokes. Although it is a major public health problem, there is no effective treatment for ICH. As a consequence of ICH, various blood components accumulate in the brain parenchyma and are responsible for much of the secondary brain damage and ICH-induced neurological deficits. Therefore, the strategies that could attenuate the blood component-induced neurotoxicity and improve hematoma resolution are highly needed. The present article provides an overview of blood-induced brain injury after ICH and emphasizes the need to conduct further studies elucidating the mechanisms of hematoma resolution after ICH.

Complement C3 participates in the function and mechanism of traumatic brain injury at simulated high altitude

BACKGROUND

Traumatic brain injury (TBI) leads to severe mortality and disability, in which secondary injury induced by complement activation plays an important role. TBI tends to be associated with more severe cerebral edema and worse neurological functional recovery if it occurs in high-altitude areas than in low-altitude areas. However, the underlying mechanism of this difference is unknown. Thus, we used cobra venom factor (CVF) to deplete complement C3 in simulated high-altitude areas to explore whether the differences in outcome at different altitudes are related to secondary injury caused by complement C3.

METHODS

The weight-drop model was adopted to induce TBI in rats. Rats were randomly divided into the following groups: sham + saline (sham), high altitude + TBI + saline (HAT), high altitude + TBI + CVF (H-CVF), low altitude + TBI + saline (LAT), and low altitude + TBI + CVF (L-CVF). Brain contusion and edema volumes, brain water content, myelin basic protein (MBP) expression, tumor necrosis factor alpha (TNF-a) expression, interleukin 1 beta (IL1B) expression, mortality rate, neurological function, and complement component 3 (C3) mRNA expression were measured by techniques such as Evans blue fluorescence, Perls staining, TUNEL staining, ELISA, immunohistochemistry and Western blotting to evaluate correlations between complement activation and secondary injury.

RESULTS

The activation of complement after TBI was significantly higher at high altitude than at low altitude. High-altitude TBI resulted in a leakier blood-brain barrier, more severe cerebral edema and higher mortality than low-altitude TBI did. In addition, high-altitude TBI tended to be associated with more MBP degradation, ferric iron deposition, neuronal apoptosis, and inflammatory factor deposition than low-altitude TBI. All of these effects of TBI were partially reversed by inhibiting complement activation using CVF.

CONCLUSION

Our study provided evidence that TBI at high altitude leads to severe edema and high mortality and disability rates. Complement C3 activation is one of the important factors contributing to secondary brain injury.

Blood-Related Toxicity after Traumatic Brain Injury: Potential Targets for Neuroprotection

Emergency visits, hospitalizations, and deaths due to traumatic brain injury (TBI) have increased significantly over the past few decades. While the primary early brain trauma is highly deleterious to the brain, the secondary injury post-TBI is postulated to significantly impact mortality. The presence of blood, particularly hemoglobin, and its breakdown products and key binding proteins and receptors modulating their clearance may contribute significantly to toxicity. Heme, hemin, and iron, for example, cause membrane lipid peroxidation, generate reactive oxygen species, and sensitize cells to noxious stimuli resulting in edema, cell death, and increased morbidity and mortality. A wide range of other mechanisms such as the immune system play pivotal roles in mediating secondary injury. Effective scavenging of all of these pro-oxidant and pro-inflammatory metabolites as well as controlling maladaptive immune responses is essential for limiting toxicity and secondary injury. Hemoglobin metabolism is mediated by key molecules such as haptoglobin, heme oxygenase, hemopexin, and ferritin. Genetic variability and dysfunction affecting these pathways (e.g., haptoglobin and heme oxygenase expression) have been implicated in the difference in susceptibility of individual patients to toxicity and may be target pathways for potential therapeutic interventions in TBI. Ongoing collaborative efforts are required to decipher the complexities of blood-related toxicity in TBI with an overarching goal of providing effective treatment options to all patients with TBI.

Clinical and experimental aspects of aneurysmal subarachnoid hemorrhage

Aneurysmal subarachnoid hemorrhage (aSAH) continues to be associated with significant morbidity and mortality despite advances in care and aneurysm treatment strategies. Cerebral vasospasm continues to be a major source of clinical worsening in patients. We intended to review the clinical and experimental aspects of aSAH and identify strategies that are being evaluated for the treatment of vasospasm. A literature review on aSAH and cerebral vasospasm was performed. Available treatments for aSAH continue to expand as research continues to identify new therapeutic targets. Oral nimodipine is the primary medication used in practice given its neuroprotective properties. Transluminal balloon angioplasty is widely utilized in patients with symptomatic vasospasm and ischemia. Prophylactic "triple-H" therapy, clazosentan, and intraarterial papaverine have fallen out of practice. Trials have not shown strong evidence supporting magnesium or statins. Other calcium channel blockers, milrinone, tirilazad, fasudil, cilostazol, albumin, eicosapentaenoic acid, erythropoietin, corticosteroids, minocycline, deferoxamine, intrathecal thrombolytics, need to be further investigated. Many of the current experimental drugs may have significant roles in the treatment algorithm, and further clinical trials are needed. There is growing evidence supporting that early brain injury in aSAH may lead to significant morbidity and mortality, and this needs to be explored further.

Comparison of the effects of nimodipine and deferoxamine on brain injury in rat with subarachnoid hemorrhage

Subarachnoid hemorrhage (SAH) may lead to brain atrophy and cognitive dysfunction. This study aimed to compare the efficacy of nimodipine and deferoxamine on these sequelae of SAH. A rat model of SAH was established by the double-hemorrhage method. These rats were injected with saline (intraperitoneal, IP), nimodipine (IP), or deferoxamine (IP and intranasal) every 12 h for 5 days after SAH. The MRI scanning, including magnetic resonance angiography, diffusion tensor imaging, T_2-weighted imaging, was performed to detect the brain structure. The levels of iron metabolism-related proteins were examined by Western blot analysis. The Morris water maze (MWM) test was used to assess the cognitive function. Then, then neurons in the cortex and hippocampus were counted on hematoxylin and eosin-stained brain sections. Significant cerebral vasospasm (CVS) was found in the saline and deferoxamine groups, but not in the nimodipine group. Cerebral peduncle injury was detected in the saline and nimodipine groups, but not significantly in the deferoxamine group. Compared with nimodipine, deferoxamine reduced transferrin (Tf), Tf receptor, and ferritin levels after SAH. The MWM performances were significantly worse in the saline and nimodipine groups than that in the deferoxamine group. Brain atrophy and neuronal losses were more significant in the saline and nimodipine groups than in the deferoxamine group. Nimodipine significantly ameliorated CVS, but it did not improve the late changes in brain structure and cognitive function. Deferoxamine effectively reduced neuronal cell death and ameliorated cognitive function after SAH.

Deferoxamine mesylate in patients with intracerebral haemorrhage (i-DEF): a multicentre, randomised, placebo-controlled, double-blind phase 2 trial

BACKGROUND

Iron from haemolysed blood is implicated in secondary injury after intracerebral haemorrhage. We aimed to assess the safety of the iron chelator deferoxamine mesylate in patients with intracerebral haemorrhage and to establish whether the drug merits investigation in a phase 3 trial.

METHODS

We did a multicentre, futility-design, randomised, placebo-controlled, double-blind, phase 2 trial at 40 hospitals in Canada and the USA. Adults aged 18-80 years with primary, spontaneous, supratentorial intracerebral haemorrhage were randomly assigned (1:1) to receive deferoxamine mesylate (32 mg/kg per day) or placebo (saline) infusions for 3 consecutive days within 24 h of haemorrhage onset. Randomisation was done via a web-based trial-management system centrally in real time, and treatment allocation was concealed from both participants and investigators. The primary outcome was good clinical outcome, which was defined as a modified Rankin Scale score of 0-2 at day 90. We did a futility analysis: if the 90% upper confidence bound of the absolute risk difference between the two groups in the proportion of participants with a good clinical outcome was less than 12% in favour of deferoxamine mesylate, then to move to a phase 3 efficacy trial would be futile. Primary outcome and safety data were analysed in the modified intention-to-treat population, comprising only participants in whom the study infusions were initiated. This trial is registered with ClinicalTrials.gov, number NCT02175225, and is completed.

FINDINGS

We recruited 294 participants between Nov 23, 2014, and Nov 10, 2017. The modified intention-to-treat population consisted of 144 patients assigned to the deferoxamine mesylate group and 147 assigned to the placebo group. At day 90, among patients with available data for the primary outcome, 48 (34%) of 140 participants in the deferoxamine mesylate group, and 47 (33%) of 143 patients in the placebo group, had modified Rankin Scale scores of 0-2 (adjusted absolute risk difference 0·6% [90% upper confidence bound 6·8%]). By day 90, 70 serious adverse events were reported in 39 (27%) of 144 patients in the deferoxamine mesylate group, and 78 serious adverse events were reported in 49 (33%) of 147 patients in the placebo group. Ten (7%) participants in the deferoxamine mesylate and 11 (7%) in the placebo group died. None of the deaths were judged to be treatment related.

INTERPRETATION

Deferoxamine mesylate was safe. However, the primary result showed that further study of the efficacy of deferoxamine mesylate with anticipation that the drug would significantly improve the chance of good clinical outcome (ie, mRS score of 0-2) at day 90 would be futile.

FUNDING

US National Institutes of Health and US National Institute of Neurological Disorders and Stroke.

Deciphering the Iron Side of Stroke: Neurodegeneration at the Crossroads Between Iron Dyshomeostasis, Excitotoxicity, and Ferroptosis

In general, iron represents a double-edged sword in metabolism in most tissues, especially in the brain. Although the high metabolic demands of brain cells require iron as a redox-active metal for ATP-producing enzymes, the brain is highly vulnerable to the devastating consequences of excessive iron-induced oxidative stress and, as recently found, to ferroptosis as well. The blood-brain barrier (BBB) protects the brain from fluctuations in systemic iron. Under pathological conditions, especially in acute brain pathologies such as stroke, the BBB is disrupted, and iron pools from the blood gain sudden access to the brain parenchyma, which is crucial in mediating stroke-induced neurodegeneration. Each brain cell type reacts with changes in their expression of proteins involved in iron uptake, efflux, storage, and mobilization to preserve its internal iron homeostasis, with specific organelles such as mitochondria showing specialized responses. However, during ischemia, neurons are challenged with excess extracellular glutamate in the presence of high levels of extracellular iron; this causes glutamate receptor overactivation that boosts neuronal iron uptake and a subsequent overproduction of membrane peroxides. This glutamate-driven neuronal death can be attenuated by iron-chelating compounds or free radical scavenger molecules. Moreover, vascular wall rupture in hemorrhagic stroke results in the accumulation and lysis of iron-rich red blood cells at the brain parenchyma and the subsequent presence of hemoglobin and heme iron at the extracellular milieu, thereby contributing to iron-induced lipid peroxidation and cell death. This review summarizes recent progresses made in understanding the ferroptosis component underlying both ischemic and hemorrhagic stroke subtypes.

Neuroinflammation, oxidative stress, and blood-brain barrier (BBB) disruption in acute Utah electrode array implants and the effect of deferoxamine as an iron chelator on acute foreign body response

The use of intracortical microelectrode arrays has gained significant attention in being able to help restore function in paralysis patients and study the brain in various neurological disorders. Electrode implantation in the cortex causes vasculature or blood-brain barrier (BBB) disruption and thus elicits a foreign body response (FBR) that results in chronic inflammation and may lead to poor electrode performance. In this study, a comprehensive insight into the acute molecular mechanisms occurring at the Utah electrode array-tissue interface is provided to understand the oxidative stress, neuroinflammation, and neurovascular unit (astrocytes, pericytes, and endothelial cells) disruption that occurs following microelectrode implantation. Quantitative real time polymerase chain reaction (qRT-PCR) was used to quantify the gene expression at acute time-points of 48-hr, 72-hr, and 7-days for factors mediating oxidative stress, inflammation, and BBB disruption in rats implanted with a non-functional 4 × 4 Utah array in the somatosensory cortex. During vascular disruption, free iron released into the brain parenchyma can exacerbate the FBR, leading to oxidative stress and thus further contributing to BBB degradation. To reduce the free iron released into the brain tissue, the effects of an iron chelator, deferoxamine mesylate (DFX), was also evaluated.

Models and methods for conditioning the ischemic brain

BACKGROUND

In the last decades the need to find new neuroprotective targets has addressed the researchers to investigate the endogenous molecular mechanisms that brain activates when exposed to a conditioning stimulus. Indeed, conditioning is an adaptive biological process activated by those interventions able to confer resistance to a deleterious brain event through the exposure to a sub-threshold insult. Specifically, preconditioning and postconditioning are realized when the conditioning stimulus is applied before or after, respectively, the harmul ischemia.

AIMS AND RESULTS

The present review will describe the most common methods to induce brain conditioning, with particular regards to surgical, physical exercise, temperature-induced and pharmacological approaches. It has been well recognized that when the subliminal stimulus is delivered after the ischemic insult, the achieved neuroprotection is comparable to that observed in models of ischemic preconditioning. In addition, subjecting the brain to both preconditioning as well as postconditioning did not cause greater protection than each treatment alone.

CONCLUSIONS

The last decades have provided fascinating insights into the mechanisms and potential application of strategies to induce brain conditioning. Since the identification of intrinsic cell-survival pathways should provide more direct opportunities for translational neuroprotection trials, an accurate examination of the different models of preconditioning and postconditioning is mandatory before starting any new project.

Research Progress in Understanding the Relationship Between Heme Oxygenase-1 and Intracerebral Hemorrhage

Intracerebral hemorrhage (ICH) is a fatal acute cerebrovascular disease, with a high morbidity and mortality. Following ICH, erythrocytes release heme and several of its metabolites, thereby contributing to brain edema and secondary brain damage. Heme oxygenase is the initial and rate-limiting enzyme of heme catabolism, and the expression of heme oxygenase-1 (HO-1) is rapidly induced following acute brain injury. As HO-1 exerts it effects via various metabolites, its role during ICH remains complex. Therefore, in-depth studies regarding the role of HO-1 in secondary brain damage following ICH may provide a theoretical basis for neuroprotective function after ICH. The present review aims to summarize recent key studies regarding the effects of HO-1 following ICH, as well as its influence on ICH prognosis.

Cerebellar Ataxia in Children: A Clinical and MRI Approach to the Differential Diagnosis

: The cerebellum has long been recognized as a fundamental structure in motor coordination. Structural cerebellar abnormalities and diseases involving the cerebellum are relatively common in children. The not always specific clinical presentation of ataxia, incoordination, and balance impairment can often be a challenge to attain a precise diagnosis. Continuous advances in genetic research and moreover the constant development in neuroimaging modalities, particularly in the field of magnetic resonance imaging, have promoted a better understanding of cerebellar diseases and led to several modifications in their classification in recent years. Thorough clinical and neuroimaging investigation is recommended for proper diagnosis. This review outlines an update of causes of cerebellar disorders that present clinically with ataxia in the pediatric population. These conditions were classified in 2 major groups, namely genetic malformations and acquired or disruptive disorders recognizable by neuroimaging and subsequently according to their features during the prenatal and postnatal periods.

Unique Properties Associated with the Brain Penetrant Iron Chelator HBED Reveal Remarkable Beneficial Effects after Brain Trauma

Iron is postulated to contribute to secondary injury after brain trauma through various pathways including oxidative stress and inflammation. Therefore, one goal is to limit iron toxicity by either directly limiting iron activity, or limiting the secondary cascade mediated by iron, therefore rescuing the brain from damage after trauma. The N,N'-Di(2-hydroxybenzyl)ethylenediamine-N,N'-diacetic acid monohydrochloride (HBED) is a unique iron chelator that has the ability to cross the intact blood-brain barrier; it has a higher affinity to iron, and it has a longer half-life than most commonly used chelators. A controlled-cortical impact model of traumatic brain injury (TBI) was induced in mice. Mice were subcutaneously injected with HBED immediately after TBI, then at 12 h after, followed by a twice-a-day regimen until an end-point of 3 days. Neurobehavioral tests were performed daily. Cortical injury volume, hemispheric enlargement, and hippocampal swelling were quantified. Perls' iron immunostaining along with markers of gliosis, oxidative stress, and aquaporin (AQP) 4 were also performed. Data revealed that HBED treatment significantly decreases motor deficits and improves recovery after TBI. It also reduces cortical injury volume by 36.6 ± 6.8% (p < 0.001), hippocampal swelling by 23.4 ± 3.8% (p < 0.05), and total hemispheric volume by 13.3 ± 2.7% (p < 0.01). These effects are related to a reduction in microgliosis and oxidiative stress markers in the impacted corpus callosum area by 39.8 ± 7.3%, and by 80.5 ± 0.8% (p < 0.05), respectively. AQP4 staining is also attenuated in the hippocampus of HBED-treated mice. Therefore, our results suggest that HBED should be considered as a therapeutic tool to facilitate the recovery process following brain trauma.

Protective effect of vitreous against hemoglobin neurotoxicity

Hemorrhage into the brain parenchyma or subarachnoid space is associated with edema and vascular injury that is likely mediated at least in part by the toxicity of hemoglobin. In contrast, extravascular blood appears to be less neurotoxic when localized to the retina or adjacent vitreous, the gel filling the posterior segment of the eye. In this study, the hypothesis that vitreous protects neurons from hemoglobin toxicity was investigated in a primary cortical cell culture model. Consistent with prior observations, hemoglobin exposure for 24 h resulted in death of most neurons without injury to co-cultured glia. Neuronal loss was reduced in a concentration-dependent fashion by bovine vitreous, with complete protection produced by 3% vitreous solutions. This effect was associated with a reduction in malondialdehyde but an increase in cell iron. At low vitreous concentrations, its ascorbate content was sufficient to account for most neuroprotection, as equivalent concentrations of ascorbate alone had a similar effect. However, other vitreous antioxidants provided significant protection when applied at concentrations present in undiluted vitreous, and prevented all neuronal loss when combined in the absence of ascorbate. These results indicate that vitreous is an antioxidant cocktail that robustly protects neurons from hemoglobin toxicity, and may contribute to the relative resistance of retinal neurons to hemorrhagic injury.