A combination of serum iron, ferritin and transferrin predicts outcome in patients with intracerebral hemorrhage

Long non-coding RNAs in intracerebral hemorrhage

Intracerebral hemorrhage (ICH), a subtype of stroke, can lead to long-term disability and is one of the leading causes of death. Unfortunately, the effectiveness of pharmacological therapy for ICH is still uncertain. Long non-coding RNA (lncRNA) was defined as an RNA molecule that consists of more than 200 nt without translational activity. As a vital class of diverse molecules, lncRNAs are involved in developmental and pathological processes and have been attractive for decades. LncRNAs have also become potential targets for therapies, as they were massively identified and profiled. In particular, emerging evidence has revealed the critical role of lncRNAs in ICH while attempts were made to treat ICH via regulating lncRNAs. But the latest evidence remains to be summarized. Thus, in this review, we will summarize the recent advances in lncRNA in ICH, highlighting the regulatory role of lncRNAs and their potential as therapeutic targets.

Imbalance of Essential Metals in Traumatic Brain Injury and Its Possible Link with Disorders of Consciousness

Dysfunction of the complex cerebral networks underlying wakefulness and awareness is responsible for Disorders of Consciousness (DoC). Traumatic Brain Injury (TBI) is a common cause of DoC, and it is responsible for a multi-dimensional pathological cascade that affects the proper functioning of the brainstem and brain consciousness pathways. Iron (Fe), Zinc (Zn), and Copper (Cu) have a role in the neurophysiology of both the ascending reticular activating system, a multi-neurotransmitter network located in the brainstem that is crucial for consciousness, and several brain regions. We aimed to summarize the role of these essential metals in TBI and its possible link with consciousness alterations. We found that TBI alters many neuronal molecular mechanisms involving essential metals, causing neurodegeneration, neural apoptosis, synaptic dysfunction, oxidative stress, and inflammation. This final pattern resembles that described for Alzheimer's disease (AD) and other neurological and psychiatric diseases. Furthermore, we found that amantadine, zolpidem, and transcranial direct current stimulation (tDCS)-the most used treatments for DoC recovery-seem to have an effect on essential metals-related pathways and that Zn might be a promising new therapeutic approach. This review summarizes the neurophysiology of essential metals in the brain structures of consciousness and focuses on the mechanisms underlying their imbalance following TBI, suggesting their possible role in DoC. The scenario supports further studies aimed at getting a deeper insight into metals' role in DoC, in order to evaluate metal-based drugs, such as metal complexes and metal chelating agents, as potential therapeutic options.

The Role of Iron-Chelating Therapy in Improving Neurological Outcome in Patients with Intracerebral Hemorrhage: Evidence-Based Case Report

Current primary intracerebral hemorrhage (ICH) treatments focus on limiting hematoma volume by lowering blood pressure, reversing anticoagulation, or hematoma evacuation. Nevertheless, there is no effective strategy to protect the brain from secondary injury due to ICH. Excess heme and iron as by-products of lysing clots in ICH might contribute to this secondary injury by triggering perihematomal edema. We present a clinical situation of an ICH case where iron-chelating therapy might be beneficial, as supported by scientific evidence. We looked through four databases (Pubmed, Cochrane, Embase, and Google Scholar) to find studies assessing the efficacy of iron-chelating therapy in ICH patients. Validity, importance, and applicability (VIA) of the included articles were appraised using worksheets from the Oxford Centre for Evidence-Based Medicine. Two out of five eligible studies were valid, important, and applicable to our patient. Both studies showed the positive effects of iron-chelating therapy on neurological outcome, as measured by National Institutes of Health Stroke Scale (NIHSS) score and modified Rankin Score (mRS). The beneficial effects of deferoxamine were demonstrated within the moderate volume (10-30 mL) subgroup, with a positive relative risk reduction (RRR) and low number needed to treat (six persons). Based on our appraisal, we considered iron-chelating therapy as an additional therapy for ICH patients, given its benefits and adverse effects. More specific studies using a larger sample size, focusing on moderate-volume ICH, and using standardized neurological outcomes are encouraged.

Identification of novel biomarkers and therapeutic target candidates for stasis-heat symptom pattern of acute intracerebral hemorrhage by quantitative plasma proteomics

OBJECTIVE

To explore the novel biomarkers and therapeutic target candidates related to the stasis-heat syndrome of acute intracerebral hemorrhage (AICH).

METHODS

Applying an isobaric tagging for relative and absolute quantitation-(iTRAQ-) based quantitative proteomic approach, plasma samples from AICH patients with stasis-heat, and AICH patients with non-stasis-heat and healthy control subjects were collected and analyzed to distinguish differentially expressed proteins (DEPs) correlated to AICH with stasis-heat in this block design. The standard Western blot was applied to verify DEPs. Additionally, DEPs were analyzed via bioinformatic platforms and further approved via Ingenuity Pathway Analysis (IPA).

RESULTS

A total of 26 DEPs were found among AICH with the stasis-heat, AICH with non-stasis-heat, and healthy control group. The seven DEPs compared with the non-stasis-heat group are closely related to the pathogenesis of stasis heat. These proteins showed three different protein expression patterns. The alpha-1-b glycoprotein (A1BG) and copper-protein (CP) were up-regulated in the stasis-heat group, but down-regulated in the non-stasis-heat group. Compared with the non-stasis-heat group, the expression abundance of actinin, alpha 1 (ACTN1), carbonic anhydrase I (CA1), peroxiredoxin 2 (PRDX2), and vinculin (VCL) is higher in the stasis-heat group, while the CD44 is the opposite. These differences reflect that stasis-heat syndrome has more severe inflammatory immune response, coagulation disorders and damage. Bioinformatics analysis revealed that a wide variety of cellular and metabolic processes and some signaling pathways were involved in the pathophysiology of AICH with stasis-heat. AICH with stasis-heat syndrome showed more severe inflammatory reactions, tissue damage, and coagulation disorders than non-stasis heat syndrome.

CONCLUSIONS

There are differences in the protein expression patterns between the stasis-heat syndrome and non-stasis-heat syndrome. These differences reflect that stasis-heat syndrome has more severe damage. CD44, CP, ACTN1, CA1, VCL, PRDX2, and A1BG could be the potential biomarkers and therapeutic target candidates of the stasis-heat subtype. This study provides a reasonable explaination for Liangxue Tongyu decoction through anti-inflammatory and brain protection treatment.

Potential Immune Indicators for Predicting the Prognosis of COVID-19 and Trauma: Similarities and Disparities

Although cellular and molecular mediators of the immune system have the potential to be prognostic indicators of disease outcomes, temporal interference between diseases might affect the immune mediators, and make them difficult to predict disease complications. Today one of the most important challenges is predicting the prognosis of COVID-19 in the context of other inflammatory diseases such as traumatic injuries. Many diseases with inflammatory properties are usually polyphasic and the kinetics of inflammatory mediators in various inflammatory diseases might be different. To find the most appropriate evaluation time of immune mediators to accurately predict COVID-19 prognosis in the trauma environment, researchers must investigate and compare cellular and molecular alterations based on their kinetics after the start of COVID-19 symptoms and traumatic injuries. The current review aimed to investigate the similarities and differences of common inflammatory mediators (C-reactive protein, procalcitonin, ferritin, and serum amyloid A), cytokine/chemokine levels (IFNs, IL-1, IL-6, TNF-α, IL-10, and IL-4), and immune cell subtypes (neutrophil, monocyte, Th1, Th2, Th17, Treg and CTL) based on the kinetics between patients with COVID-19 and trauma. The mediators may help us to accurately predict the severity of COVID-19 complications and follow up subsequent clinical interventions. These findings could potentially help in a better understanding of COVID-19 and trauma pathogenesis.

Small interfering RNAs based therapies for intracerebral hemorrhage: challenges and progress in drug delivery systems

Intracerebral hemorrhage (ICH) is a subtype of stroke associated with higher rates of mortality. Currently, no effective drug treatment is available for ICH. The molecular pathways following ICH are complicated and diverse. Nucleic acid therapeutics such as gene knockdown by small interfering RNAs (siRNAs) have been developed in recent years to modulate ICH’s destructive pathways and mitigate its outcomes. However, siRNAs delivery to the central nervous system is challenging and faces many roadblocks. Existing barriers to systemic delivery of siRNA limit the use of naked siRNA; therefore, siRNA-vectors developed to protect and deliver these therapies into the specific-target areas of the brain, or cell types seem quite promising. Efficient delivery of siRNA via nanoparticles emerged as a viable and effective alternative therapeutic tool for central nervous system-related diseases. This review discusses the obstacles to siRNA delivery, including the advantages and disadvantages of viral and nonviral vectors. Additionally, we provide a comprehensive overview of recent progress in nanotherapeutics areas, primarily focusing on the delivery system of siRNA for ICH treatment.

Scalp Acupuncture Protects Against Neuronal Ferroptosis by Activating The p62-Keap1-Nrf2 Pathway in Rat Models of Intracranial Haemorrhage

Intracerebral haemorrhage (ICH) can be a catastrophic event; even if the initial stages of the pathology were well-managed, a number of patients experience varied residual neurological deficits following the insult. Ferroptosis is a recently identified type of cell demise which is tightly linked to the neurological impairment associated with ICH. In the current work, the prophylactic impact of scalp acupuncture (SA) therapy on autologous blood injection murine models of ICH was investigated in order to establish whether SA could mitigate the secondary damage arising following ICH by moderating ferroptosis. The pathophysiological mechanisms associated with this process were also explored. Ludmila Belayev tests were utilised for the characterisation of neurological damage. Haematoxylin–eosin staining was employed in order to determine the cerebral impact of the induced ICH. Malondialdehyde (MDA) and iron titres in peri-haemorrhagic cerebral tissues were appraised using purchased assay kits. Transmission electron microscopy delineated mitochondrial appearances within nerve cell bodies from the area of haemorrhage. Western blotting techniques were utilised to assay the degree of protein expression of NeuN, sequestosome 1 (p62), nuclear factor erythroid 2-related factor 2 (Nrf2), Kelch-like ECH-associated protein 1 (Keap1), glutathione peroxidase 4 (GPX4) and ferritin heavy chain 1 (FTH1). The frequencies of Nrf2, GPX4 and FTH1 positive cells, respectively, were documented with immunohistochemical staining. The results demonstrated that therapy with SA after ICH mitigated MDA and iron sequestration, diminished the appearance of contracted mitochondria with increased outer mitochondrial membrane diameter within the nerve cell bodies, and suppressed neuronal ferroptosis. The pathways responsible for these effects may encompass amplified p62, Nrf2, GPX4 and FTH1 expression, together with decreased Keap1 expression. Application of SA reduced identified neurobehavioural abnormalities after ICH; no disparities were observed between the consequences of SA therapy and deferoxamine delivery. It can be surmised that intervention with SA enhanced recovery after ICH by triggering the antioxidant pathway, p62/Keap1/Nrf2, and causing FTH1 and GPX4 upregulation, factors that participate in diminishing excess iron and thus in mitigating lipid peroxidation insults arising from ferroptosis following ICH.

Potential therapeutic effects of Nrf2 activators on intracranial hemorrhage

Intracranial hemorrhage (ICH) is a devastating disease which induces high mortality and poor outcomes including severe neurological dysfunctions. ICH pathology is divided into two types: primary brain injury (PBI) and secondary brain injury (SBI). Although there are numerous preclinical studies documenting neuroprotective agents in experimental ICH models, no effective drugs have been developed for clinical use due to complicated ICH pathology. Oxidative and inflammatory stresses play central roles in the onset and progression of brain injury after ICH, especially SBI. Nrf2 is a crucial transcription factor in the anti-oxidative stress defense system. Under normal conditions, Nrf2 is tightly regulated by the Keap1. Under ICH pathological conditions, such as overproduction of reactive oxygen species (ROS), Nrf2 is translocated into the nucleus where it up-regulates the expression of several anti-oxidative phase II enzymes such as heme oxygenase-1 (HO-1). Recently, many reports have suggested the therapeutic potential of Nrf2 activators (including natural or synthesized compounds) for treating neurodegenerative diseases. Moreover, several Nrf2 activators attenuate ischemic stroke-induced brain injury in several animal models. This review summarizes the efficacy of several Nrf2 activators in ICH animal models. In the future, Nrf2 activators might be approved for the treatment of ICH patients.

Prognostication after intracerebral hemorrhage: a review

Background

Approximately half of patients with spontaneous intracerebral hemorrhage (ICH) die within 1 year. Prognostication in this context is of great importance, to guide goals of care discussions, clinical decision-making, and risk stratification. However, available prognostic scores are hardly used in clinical practice. The purpose of this review article is to identify existing outcome prediction scores for spontaneous intracerebral hemorrhage (ICH) discuss their shortcomings, and to suggest how to create and validate more useful scores.

Main text

Through a literature review this article identifies existing ICH outcome prediction models. Using the Essen-ICH-score as an example, we demonstrate a complete score validation including discrimination, calibration and net benefit calculations. Score performance is illustrated in the Erlangen UKER-ICH-cohort (NCT03183167). We identified 19 prediction scores, half of which used mortality as endpoint, the remainder used disability, typically the dichotomized modified Rankin score assessed at variable time points after the index ICH. Complete score validation by our criteria was only available for the max-ICH score. Our validation of the Essen-ICH-score regarding prediction of unfavorable outcome showed good discrimination (area under the curve 0.87), fair calibration (calibration intercept 1.0, slope 0.84), and an overall net benefit of using the score as a decision tool. We discuss methodological pitfalls of prediction scores, e.g. the withdrawal of care (WOC) bias, physiological predictor variables that are often neglected by authors of clinical scores, and incomplete score validation. Future scores need to integrate new predictor variables, patient-reported outcome measures, and reduce the WOC bias. Validation needs to be standardized and thorough. Lastly, we discuss the integration of current ICH scoring systems in clinical practice with the awareness of their shortcomings.

Conclusion

Presently available prognostic scores for ICH do not fulfill essential quality standards. Novel prognostic scores need to be developed to inform the design of research studies and improve clinical care in patients with ICH.

Supplementary Information

The online version contains supplementary material available at 10.1186/s42466-021-00120-5.

Iron Metabolism Disorders for Cognitive Dysfunction After Mild Traumatic Brain Injury

Traumatic brain injury (TBI) is one of the most harmful forms of acute brain injury and predicted to be one of the three major neurological diseases that cause neurological disabilities by 2030. A series of secondary injury cascades often cause cognitive dysfunction of TBI patients leading to poor prognosis. However, there are still no effective intervention measures, which drive us to explore new therapeutic targets. In this process, the most part of mild traumatic brain injury (mTBI) is ignored because its initial symptoms seemed not serious. Unfortunately, the ignored mTBI accounts for 80% of the total TBI, and a large part of the patients have long-term cognitive dysfunction. Iron deposition has been observed in mTBI patients and accompanies the whole pathological process. Iron accumulation may affect long-term cognitive dysfunction from three pathways: local injury, iron deposition induces tau phosphorylation, the formation of neurofibrillary tangles; neural cells death; and neural network damage, iron deposition leads to axonal injury by utilizing the iron sensibility of oligodendrocytes. Thus, iron overload and metabolism dysfunction was thought to play a pivotal role in mTBI pathophysiology. Cerebrospinal fluid-contacting neurons (CSF-cNs) located in the ependyma have bidirectional communication function between cerebral-spinal fluid and brain parenchyma, and may participate in the pathway of iron-induced cognitive dysfunction through projected nerve fibers and transmitted factor, such as 5-hydroxytryptamine, etc. The present review provides an overview of the metabolism and function of iron in mTBI, and to seek a potential new treatment target for mTBI with a novel perspective through combined iron and CSF-cNs.

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.

Hepcidin inhibits autophagy in intracerebral hemorrhage models in vitro and in vivo

Iron has a key role in the activation of the autophagic pathway in rats with intracerebral hemorrhage (ICH), and hepcidin has the ability to reduce brain iron in ICH-rats. We therefore hypothesized that hepcidin might be able to inhibit autophagy by reducing iron in an ICH brain. Here, we investigated the effects of Ad-hepcidin and/or hepcidin peptide on autophagic activities in ICH models in vitro and in vivo. We demonstrated that ad-hepcidin and hepcidin peptide both inhibited hemin-induced increase in LC3-II/LC3-I conversion ratio and reversed the reduction in p62 content in cortical neurons in vitro. We also showed that ad-hepcidin inhibited ICH-induced increase in LC3-II/LC3-I conversion ratio and reversed ICH-induced reduction in p62 content in the brain cortex of rats in vivo. Based on these findings plus previous data on the effects of ad-hepcidin and/or hepcidin peptide on iron contents in ICH models, we suggested that hepcidin-induced inhibition of autophagy might be mediated via reducing iron in hemin-treated neurons in vitro and ICH-rat brain in vivo.

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.

Mechanical injury and blood are drivers of spatial memory deficits after rapid intraventricular hemorrhage

Aneurysmal intraventricular hemorrhage (IVH) survivors may recover with significant deficits in learning and memory. The goal of this study was to investigate the mechanism of memory decline after intraventricular aneurysm rupture. We developed an aneurysmal IVH rat model by injecting autologous, arterial blood over the period of two minutes into the right lateral ventricle. We also evaluated the effects of a volume-matched artificial cerebrospinal fluid (CSF) control, thrombin and the mode of delivery (pulsed hand injection versus continuous pump infusion). We performed magnetic resonance brain imaging after 1 and 5 weeks to evaluate for hydrocephalus and histological analysis of the dentate gyrus after 6 weeks. Only animals which underwent a whole blood pulsed hand injection had a spatial memory acquisition and retention deficit 5 weeks later. These animals had larger ventricles at 1 and 5 weeks than animals which underwent a continuous pump infusion of whole blood. We did not find a decline in dentate gyrus granule cell neurons or an impairment in dentate gyrus neurogenesis or differentiation 6 weeks after IVH. Rapid injections of blood or volume resulted in microglial activation in the dentate gyrus. In conclusion, our results point to mechanical injury as the predominant mechanism of memory decline after intraventricular aneurysmal rupture. However, volume-matched pulsed injections of artificial CSF did not create a spatial memory deficit at 5 weeks. Therefore, whole blood itself must play a role in the mechanism. Further research is required to evaluate whether the viscosity of blood causes additional mechanical disruption and hydrocephalus through a primary injury mechanism or whether the toxicity of blood causes a secondary injury mechanism that leads to the observed spatial memory deficit after 5 weeks.

Deferasirox, a trivalent iron chelator, ameliorates neuronal damage in hemorrhagic stroke models

PURPOSE

Intracranial hemorrhage (ICH) is a devastating disease with high mortality and morbidity. After ICH, iron released from the hematoma plays a crucial role in secondary brain injury. Deferasirox (DFR) is a trivalent iron chelator, which was approved to treat iron overload syndrome after transfusion. The aim of the present study was to investigate the protective effects of DFR in both in vitro and in vivo ICH models.

METHODS

Using a hemin-induced SH-SY5Y cell damage model, we performed an intracellular bivalent iron (Fe²⁺) accumulation assay, cell death assay, oxidative stress assessments, and Western blotting analysis. Moreover, the effects of DFR intraventricular administration on hematoma, neurological deficits, and histological alteration were evaluated in an in vivo ICH mouse model by collagenase.

RESULTS

DFR significantly suppressed the intracellular Fe²⁺ accumulation and cell death caused by hemin exposure. These effects were related to the suppression of both reactive oxygen species and lipid peroxidation over-production. In Western blotting analysis, hemin increased the expression of ferritin (an iron storage protein), LC3 and p62 (autophagy-related markers), phosphorylated p38 (a stress response protein), and cleaved-caspase3 and cleaved-poly (adenosine diphosphate ribose) polymerase (PARP) (apoptosis-related makers). However, DFR suppressed the increase of these proteins. In addition, DFR attenuated the neurological deficits until 7 days after ICH without affecting hematoma and injury area. Furthermore, DFR also suppressed microglia/macrophage activation in peri-hematoma area at 3 days after ICH.

CONCLUSION

These findings indicate that DFR might be a useful therapeutic agent for the therapy of ICH.

Brainstem iron overload and injury in a rat model of brainstem hemorrhage

BACKGROUND AND PURPOSE

Brainstem hemorrhage (BSH) is the most devastating subtype of intracerebral hemorrhage (ICH) with the highest mortality ranging from 56 % to 61.2 %. However, there is no effective medical or surgical therapy to improve its outcomes in clinic to date due to lack of understanding of its injury mechanisms. Herein, we explored the brainstem iron overload and injury in a rat model of BSH.

METHODS

Neurological scores were examined on day 1, 3, and 7 after modeling, and mortality of the rats was recorded to draft a survival curve. Rats were monitored by MRI using T2 and susceptibility weighted imaging (SWI) before sacrifice for examination of histology and immunofluorescence on day 1, 3, and 7.

RESULTS

BSH rats had a high mortality of 56 % and demonstrated the severe neurological deficits mimicking the clinical conditions. SWI showed that the same increasing tendency in change of hypointense area with that in iron deposition by Perls staining from day 1 to 7. Expression of heme oxygenase 1 (HO-1) and generation of reactive oxygen species (ROS) had similar tendency and both peaked on day 3. Neuronal degeneration occurred and stayed elevated from day 1 to 7, while myelin sheath injury was initially observed on day 1 but without significant difference within 7 days.

CONCLUSIONS

The time courses of erythrocyte lysis, HO-1 expression, iron deposition and ROS generation are related to each other after BSH. Besides, brainstem injury including neuronal degeneration and myelin damage were observed and discussed.

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.

Deferoxamine Alleviates Iron Overload and Brain Injury in a Rat Model of Brainstem Hemorrhage

BACKGROUND

Brainstem hemorrhage (BSH) is the most dangerous and devastating subtype of intracerebral hemorrhage and is associated with high morbidity and mortality. However, to date, no effective prevention methods or specific therapies have been available to improve its clinical outcomes. We preliminarily explored the efficacy of deferoxamine (DFO), a clinical chelator known for its iron-scavenging activities, in a rat model of BSH induced with collagenase infusion.

METHODS

DFO or saline was administrated 6 hours after BSH induction and then every 12 hours for ≤7 days. The survival curve of the rats was created, and the neurological scores were examined on days 1, 3, and 7 after BSH. The rats were sacrificed after 1, 3, and 7 days of DFO treatment for histological examination and immunohistochemistry.

RESULTS

The results showed that administration of DFO delayed erythrocytes lysis, reduced iron deposition, reduced reactive oxygen species generation, reduced heme oxygenase-1 expression, and alleviated brain injury such as neuron degeneration and myelin sheath injury. However, DFO did not improve the survival rate and neurobehavioral outcomes in this model.

CONCLUSIONS

Administration of DFO had limited therapeutic effects on collagenase-induced brainstem hemorrhage in rats. Some potential explanations were proposed, and more preclinical work is required to clarify the controversial curative effect of DFO in ICH.

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.

Testing a Multivariate Proteomic Panel for Traumatic Brain Injury Biomarker Discovery: A TRACK-TBI Pilot Study

The complex and heterogeneous nature of traumatic brain injury (TBI) has rendered the identification of diagnostic and prognostic biomarkers elusive. A single acute biomarker may not be sufficient to categorize injury severity and/or predict outcome. Using multivariate dimension reduction analyses, we tested the sensitivity and specificity of a multi-analyte panel of proteins as an ensemble biomarker for TBI. Serum was collected within 24 h of injury in a cohort of 130 patients enrolled in the multi-center prospective Transforming Research and Clinical Knowledge in Traumatic Brain Injury Pilot (TRACK-TBI Pilot) study and run on an array that measured 72 proteins. Using unsupervised principal components analysis, we first identified the subset of protein changes accounting for the most variance across patients. This yielded a group of 21 proteins that reflected an inverse relationship between inflammatory cytokines and regulators of anti-inflammation, and generated an individual inflammatory profile score for each patient. We then tested the association between these scores and computed tomography (CT) findings at hospital admission, as well as their prognostic association with functional recovery at 3 and 6 months (Glasgow Outcome Scale-Extended), and cognitive recovery at 6 months (California Verbal Learning Test, Second Edition) after injury. Inflammatory signatures were significantly increased in patients with positive CT findings, as well as in those who showed poor or incomplete recovery. Inflammation biomarker scores also showed significant sensitivity and specificity as a discriminator of these outcome measures (all areas under the curve [AUCs] >0.62). This proof of concept for the feasibility of multivariate biomarker identification demonstrates the prognostic validity of using a proteomic panel as a potential biomarker for TBI.

Tissue iron is negatively correlated with TERC or TERT mRNA expression: A heterochronic parabiosis study in mice

To test the hypothesis that iron accumulation in tissues with age is a key harmful factor for the development of aging, we established heterochronic parabiosis-pairings and investigated changes in serum iron, the expression of major iron transport proteins and iron contents, as well as telomerase reverse transcriptase (TERT), telomerase RNA component (TERC), and telomere length in the liver, kidney and heart of Y-O(O) (old pairing with young), Y-O(Y) (young pairing with old), O-O (pairings between two old) and Y-Y (pairings between two young) mice. We demonstrated that the reduced serum iron, increased iron and reduced expression of TERT and TERC in the tissues of aged mice are reversible by exposure to a younger mouse’s circulation. All of these measurements in young mice are reversible by exposure to an older mouse’s circulation. Correlation analysis showed that tissue iron is negatively correlated with TERT and TERC expression in the liver, kidney and heart of parabiotic mice. These findings provide new evidence for the key role of iron in aging and also imply the existence of rejuvenating factors in young serum with an anti-ageing role that act by reversing the impaired activity of iron metabolism in old mice.

Predictive value of iron parameters in neurocritically ill patients

BACKGROUND

Iron, an essential mineral for human body, has the potential to cause toxicity at high levels. Previous studies have shown inconsistent predictive value of iron parameters in critically ill patients. Thus, we aimed to evaluate the performance of iron parameters in outcome prediction of neurocritically ill patients.

METHODS

Retrospective data were collected from patients admitted to the neurocritical care unit (NCU) of a tertiary teaching hospital between August 2016 and January 2017. The iron parameters were obtained at NCU admission. Primary endpoints were short-term (30-day) mortality and long-term (6-month) poor outcome, with the latter defined as modified Rankin Scale of 4-6. The predictive value of variables was determined with univariate and multivariate logistic analysis. A further subanalysis was conducted in patients stratified by the level of estimated glomerular filtration rate (eGFR).

RESULTS

Of 103 eligible patients, the etiology included stroke (58.2%, N = 60), central nervous system infection (13.6%, N = 14), and other neurologic disorders (28.2%, N = 29). The correlation analysis showed that the increase in ferritin, as well as the reduction in transferrin and total iron-binding capacity, had strong correlation with C-reactive protein, procalcitonin, duration of NCU stay, Acute Physiology and Chronic Health Evaluation II score, and Sequential Organ Failure Assessment score. In a further subanalysis of 75 patients with eGFR ≥ 60 ml/min/1.73 m² , twelve (16.0%) patients died within 30 days and 39 (52.0%) patients achieved good follow-up outcome data. In the multivariate logistic regression analysis, we identified baseline ferritin level as an independent predictor of short-term mortality (OR: 1.002; 95% CI: 1.000-1.003; p = 0.008) and long-term functional outcome (OR: 1.002; 95% CI: 1.000-1.004; p = 0.031).

CONCLUSIONS

Serum ferritin level at admission could be used as an independent predictor of short-term mortality and long-term functional outcome in neurocritically ill patients with eGFR ≥ 60 ml/min/1.73 m² .

Hepcidin Protects Neuron from Hemin-Mediated Injury by Reducing Iron

Hemin plays a key role in mediating secondary neuronal injury after intracerebral hemorrhage (ICH) and the cell toxicity of hemin is thought to be due to iron that is liberated when hemin is degraded. In a recent study, we demonstrated the iron regulatory hormone hepcidin reduces brain iron in iron-overloaded rats. Therefore, we hypothesized that hepcidin might be able to reduce iron and then protect neurons from hemin or iron-mediated neurotoxicity in hemin-treated neuronal cells. Here, we tested the hypothesis and demonstrated that ad-hepcidin and hepcidin peptide both have the ability to suppress the hemin-induced increase in LDH release and apoptotic cell numbers, to reduce cell iron and ferritin contents, and to inhibit expression of transferrin receptor 1, divalent metal transporter 1, and ferroportin 1 in hemin-treated neurons. We conclude that hepcidin protects neuron from hemin-mediated injury by reducing iron via inhibition of expression of iron transport proteins.

Biomarkers of Functional Outcome in Intracerebral Hemorrhage: Interplay between Clinical Metrics, CD163, and Ferritin

BACKGROUND

Intracerebral hemorrhage (ICH) is associated with neurological decline and poor prognosis. Although many etiologic models have been explored, secondary damage caused by continued inflammation and iron exposure from red blood cell lysis may explain poor outcomes at distant follow-up. Examining serum samples of patients with ICH for biomarkers of iron physiology may yield relationships between iron exposure and functional outcomes.

METHODS

The following study retrospectively evaluated 41 patient serum samples obtained 1 day and 7 days post-ictus for CD163, ferritin, and hepcidin concentrations. Functional outcomes, using the modified Rankin Scale, were dichotomized into good (0-3) and poor (4-6). Correlation analysis and logistic regression were used to explore relationships between biomarker values, clinical metrics (such as ICH Score), and functional outcomes at 3 and 12 months.

RESULTS

Clinical metrics (Acute Physiology and Chronic Health Evaluation II score, ICH Score, and National Institutes of Health Stroke Scale) were correlated with elevated ferritin levels 7 days post-ictus. Furthermore, it was found that mean CD163 levels on day 1 were significantly associated with functional outcomes at 3 and 12 months; mean serum ferritin concentrations on days 1 and 7 were elevated in those with poor outcomes at 3 months, and day 7 levels were independently correlated with 12-month outcomes.

CONCLUSION

Although this study serves to contribute to a growing body of evidence that CD163 and ferritin are biomarkers of functional outcomes, prospective cohort studies may clarify the role of iron-related inflammatory biomarkers as they pertain to neurological decline in patients with ICH.

Brain iron overload following intracranial haemorrhage

Intracranial haemorrhages, including intracerebral haemorrhage (ICH), intraventricular haemorrhage (IVH) and subarachnoid haemorrhage (SAH), are leading causes of morbidity and mortality worldwide. In addition, haemorrhage contributes to tissue damage in traumatic brain injury (TBI). To date, efforts to treat the long-term consequences of cerebral haemorrhage have been unsatisfactory. Incident rates and mortality have not showed significant improvement in recent years. In terms of secondary damage following haemorrhage, it is becoming increasingly apparent that blood components are of integral importance, with haemoglobin-derived iron playing a major role. However, the damage caused by iron is complex and varied, and therefore, increased investigation into the mechanisms by which iron causes brain injury is required. As ICH, IVH, SAH and TBI are related, this review will discuss the role of iron in each, so that similarities in injury pathologies can be more easily identified. It summarises important components of normal brain iron homeostasis and analyses the existing evidence on iron-related brain injury mechanisms. It further discusses treatment options of particular promise.

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

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