Body iron stores and early neurologic deterioration in acute cerebral infarction

Natural flavonoids from herbs and nutraceuticals as ferroptosis inhibitors in central nervous system diseases: current preclinical evidence and future perspectives

Flavonoids are a class of important polyphenolic compounds, renowned for their antioxidant properties. However, recent studies have uncovered an additional function of these natural flavonoids: their ability to inhibit ferroptosis. Ferroptosis is a key mechanism driving cell death in central nervous system (CNS) diseases, including both acute injuries and chronic neurodegenerative disorders, characterized by iron overload-induced lipid peroxidation and dysfunction of the antioxidant defense system. This review discusses the therapeutic potential of natural flavonoids from herbs and nutraceuticals as ferroptosis inhibitors in CNS diseases, focusing on their molecular mechanisms, summarizing findings from preclinical animal models, and providing insights for clinical translation. We specifically highlight natural flavonoids such as Baicalin, Baicalein, Chrysin, Vitexin, Galangin, Quercetin, Isoquercetin, Eriodictyol, Proanthocyanidin, (-)-epigallocatechin-3-gallate, Dihydromyricetin, Soybean Isoflavones, Calycosin, Icariside II, and Safflower Yellow, which have shown promising results in animal models of acute CNS injuries, including ischemic stroke, cerebral ischemia-reperfusion injury, intracerebral hemorrhage, subarachnoid hemorrhage, traumatic brain injury, and spinal cord injury. Among these, Baicalin and its precursor Baicalein stand out due to extensive research and favorable outcomes in acute injury models. Mechanistically, these flavonoids not only regulate the Nrf2/ARE pathway and activate GPX4/GSH-related antioxidant pathways but also modulate iron metabolism proteins, thereby alleviating iron overload and inhibiting ferroptosis. While flavonoids show promise as ferroptosis inhibitors for CNS diseases, especially in acute injury settings, further studies are needed to evaluate their efficacy, safety, pharmacokinetics, and blood-brain barrier penetration for clinical application.

OSGEP, A Negative Ferroptotic Regulator, Alleviates Cerebral Ischemia-Reperfusion Injury Through Modulating m6A Methylation of GPX4 mRNA

Cerebral ischemia-reperfusion injury (CIRI) is a devastating condition that triggers neuronal death and cerebral infarction. O-sialoglycoprotein endopeptidase (OSGEP), identified as a crucial element of the highly conserved KEOPS complex, regulated cellular proliferation and mitochondrial metabolism. Despite its known role in cellular homeostasis, the potential contribution of OSGEP to the development of CIRI remains elusive. This study was designed to investigate the potential role of ferroptosis in the pathogenesis of CIRI and indicate whether OSGEP could suppress ferroptosis to alleviate CIRI by modulating GPX4 m6A methylation. To this end, MCAO and OGD/R models were employed to closely simulate the CIRI. The potent ferroptosis inhibitors conferred prominent neuroprotection in both in vivo and in vitro models. Moreover, OSGEP expression level was not only downregulated in MCAO-treated mice and in cultured cerebrocortical neurons subjected to OGD/R, but also it was related to the prognosis of acute ischemic stroke (AIS) cases. Additionally, OSGEP overexpression exerted potent anti-ferroptotic effects in both MCAO and OGD/R models, while OSGEP depletion exhibited the opposite effect. Moreover, OSGEP regulated GPX4 expression by modulating m6A methylation of its mRNA. Furthermore, the inhibitory effect of OSGEP on ferroptosis was dependent on the presence of GPX4. Specifically, OSGEP knockout exacerbated ferroptosis-like cell death under MCAO condition. Besides, OSGEP regulated GPX4 mRNA stability through competition with YTHDC1 for binding to GPX4 mRNA and forming a complex with HNRNPUL1 in the neuronal primary cultures subjected to OGD/R. These findings highlighted the critical role of OSGEP, as a new contributing anti-ferroptotic factor, in the pathogenesis of CIRI.

The prognostic role of iron deficiency in acute ischemic stroke patients: A prospective multicentric cohort study

BACKGROUND AND AIMS

Iron deficiency (ID) is a prognostic factor in heart failure and acute coronary syndrome. However, its role in cerebrovascular diseases is controversial. We aimed to determine the impact of ID on the functional outcome of acute ischemic stroke patients.

METHODS

This was an observational prospective multicentric cohort study. From January to December 2023, we enrolled acute ischemic stroke patients admitted to the stroke units of four comprehensive stroke centers. Venous blood samples were collected at admission to determine the iron status (serum iron, ferritin, transferrin). ID was defined as a serum ferritin concentration < 100 ng/mL or 100-299 ng/mL with transferrin saturation (TSAT) <20 %. The primary endpoint was the poor functional outcome at 90 days defined as modified Rankin Scale (mRS) 3-6. We used binary logistic regression models including confounding factors to test the association between ID and the primary outcome.

RESULTS

The analysis included 442 patients (mean age 73 ± 13, 47.5 % female, median NIHSS 7 [IQR 3-15], 61.3 % treated with intravenous thrombolysis and/or endovascular treatment). ID prevalence was 65.6 %. In all binary logistic regression models, ID predicted poor functional outcome at 3 months irrespective from demographics, stroke severity and characteristics, anemia, risk factors, signs/symptoms of heart failure, glucose at admission, and inflammatory biomarkers (aOR 2.328, 95 % CI 1.272-4.263, p = 0.006).

CONCLUSIONS

ID was strongly associated with poor functional outcome at 90 days in acute ischemic stroke patients. Further research is required to explore whether iron supplementation could be a potential therapeutic strategy to improve patient outcomes.

Association between iron content in grey matter nuclei and functional outcome in patients with acute ischaemic stroke: A quantitative susceptibility mapping study

BACKGROUND AND PURPOSE

This study aimed to investigate the association between iron content in grey matter (GM) nuclei and functional outcome in acute ischaemic stroke (AIS) patients utilizing quantitative susceptibility mapping.

METHODS

Forty AIS patients and 40 age-, sex- and education-matched healthy controls underwent quantitative susceptibility mapping to assess susceptibility values, which are positively correlated with iron content, in the caudate nucleus, putamen, globus pallidus, thalamus, red nucleus and substantia nigra. The nuclei on the contralateral side were measured in AIS patients to minimize confounding due to oedema or haemorrhage. Functional outcome was determined by the modified Rankin Scale (mRS) score at 3 months after stroke. Poor outcome was defined as mRS >2, whilst a good outcome was defined as ≤2.

RESULTS

Susceptibility values were significantly higher in most contralateral GM nuclei in AIS patients than in the corresponding left or right nuclei in healthy controls. AIS patients with poor outcome showed significantly lower susceptibility value than those with good outcome in the contralateral caudate nucleus, but no significant differences were observed in other GM nuclei. Binary logistic regression analysis revealed a significant association between the susceptibility value of the contralateral caudate nucleus and poor outcome after adjustment for confounders (adjusted odds ratio 0.692, 95% confidence interval 0.486-0.986, p = 0.042). Receiver operating characteristic curve analysis showed an acceptable ability of the susceptibility value of the contralateral caudate nucleus to predict poor outcome (area under the curve 0.740, p = 0.013).

CONCLUSIONS

Lower iron content in the contralateral caudate nucleus was associated with poor functional outcome in AIS patients.

Ferritin Levels on Hospital Admission Predict Hypoxic-Ischemic Encephalopathy in Patients After Out-of-Hospital Cardiac Arrest: A Prospective Observational Single-Center Study

AIM

Out-of-hospital cardiac arrest (OHCA) is a major health concern in Western societies. Poor outcome after OHCA is determined by the extent of hypoxic-ischemic encephalopathy (HIE). Dysregulation of iron metabolism has prognostic relevance in patients with ischemic stroke and sepsis. The aim of this study was to determine whether serum iron parameters help to estimate outcomes after OHCA.

METHODS

In this prospective single-center study, 70 adult OHCA patients were analyzed. Serum ferritin, iron, transferrin (TRF), and TRF saturation (TRFS) were measured in blood samples drawn on day 0 (admission), day 2, day 4, and 6 months after the return of spontaneous circulation (ROSC). The association of 4 iron parameters with in-hospital mortality, neurological outcome (cerebral performance category [CPC]), and HIE was investigated by receiver operating characteristics and multivariate regression analyses.

RESULTS

OHCA subjects displayed significantly increased serum ferritin levels on day 0 and lowered iron, TRF, and TRFS on days 2 and 4 after ROSC, as compared to concentrations measured at a 6-month follow-up. Iron parameters were not associated with in-hospital mortality or neurological outcomes according to the CPC. Ferritin on admission was an independent predictor of features of HIE on cranial computed tomography and death due to HIE.

CONCLUSION

OHCA is associated with alterations in iron metabolism that persist for several days after ROSC. Ferritin on admission can help to predict HIE.

Mechanism of ferroptosis regulating ischemic stroke and pharmacologically inhibiting ferroptosis in treatment of ischemic stroke

Ferroptosis is a newly discovered form of programmed cell death that is non-caspase-dependent and is characterized by the production of lethal levels of iron-dependent lipid reactive oxygen species (ROS). In recent years, ferroptosis has attracted great interest in the field of cerebral infarction because it differs morphologically, physiologically, and genetically from other forms of cell death such as necrosis, apoptosis, autophagy, and pyroptosis. In addition, ROS is considered to be an important prognostic factor for ischemic stroke, making it a promising target for stroke treatment. This paper summarizes the induction and defense mechanisms associated with ferroptosis, and explores potential treatment strategies for ischemic stroke in order to lay the groundwork for the development of new neuroprotective drugs.

Which one predicts mortality better in acute ischemic stroke: negative vs positive acute-phase reactants

AIM

The aim of the study is to investigate the relationship between negative acute-phase reactants and positive acute-phase reactants with in-hospital mortality in patients diagnosed with acute ischemic stroke (AIS) in the emergency department (ED).

METHODS AND MATERIALS

Patients aged 18 and older who presented to the ED of a tertiary hospital with AIS were included in the study. Demographic and clinical characteristics, laboratory parameters, acute-phase reactants, National Institutes of Health Stroke Scale (NIHSS), and outcome data of the included patients were recorded on a standard data form.

RESULTS

A total of 588 patients were included in the study. When the in-hospital mortality of patients was examined, the mortality rate was 17.7%. In the analysis for predicting mortality, it was determined that albumin had the highest predictive power between the area under the curve (AUC) and the determined predictive values (AUC: 0.759, 95% CI 0.707-0.810, p < 0.001). The analyses of the study data revealed that albumin (<0.001) and TF (p = 0.049), which are negative acute-phase reactants, were independent predictors of mortality. According to our study data, in patients with AIS, for each unit decrease in albumin level at the time of ED admission, the risk of mortality increased by 0.868 times, and for each unit decrease in TF level, the risk of mortality increased by 0.593 times.

CONCLUSION

According to the study data, albumin and TF levels, which are negative acute-phase reactants, are independent determinants of in-hospital mortality in patients with acute ischemic stroke in the emergency department.

Electroacupuncture pretreatment alleviates rats cerebral ischemia-reperfusion injury by inhibiting ferroptosis

Objective

To explore the preventive effect of electroacupuncture pretreatment on stroke in rats by inhibiting ferroptosis and oxidative stress.

Methods

Rats were randomly assigned to the sham, middle cerebral artery occlusion/reperfusion (MCAO/R), MCAO/R + EP, MCAO/R + EP + erastin, and MCAO/R + EP + ferrostatin 1 groups. Daily electroacupuncture was performed 2 weeks before establishing the MCAO/R model utilizing the modified Zea Longa suture method. Rats were sacrificed 1 day after reperfusion, and brain tissues were collected. They were prepared for hematoxylin and eosin staining, prussian blue staining, transmission electron microscope. Measurement of total iron levels using a commercial kit, detection of malondialdehyde (MDA) and superoxide dismutase (SOD) levels by ELISA, and examination of 15-lox2, GPX4, SLC7A11, ACSL4, and TFR1 by western blotting.

Results

Compared with sham rats, cerebral infarction size was dramatically larger in MCAO/R rats. Moreover, the MCAO/R group displayed damaged mitochondria with a disarranged structure of cristae; free iron, total iron levels, and oxidative stress were significantly higher. Cerebral pathological lesions, oxidative stress, total iron levels, and protein levels of ACSL4, TFR1, and 15-lox2 were significantly reduced in the MCAO/R + EP and MCAO/R + EP + ferrostatin 1 groups, while the protective effect of electroacupuncture pretreatment on cerebral ischemia-reperfusion injury was inhibited by treatment with the ferroptosis activator erastin.

Conclusion

Electroacupuncture pretreatment can protect rats from cerebral ischemia-reperfusion injury by reducing the area of cerebral infarction and inhibiting ferroptosis and oxidative stress.

Evaluation of brain iron deposition in different cerebral arteries of acute ischaemic stroke patients using quantitative susceptibility mapping

AIM

To investigate differences in iron deposition between infarct and normal cerebral arterial regions in acute ischaemic stroke (AIS) patients using quantitative susceptibility mapping (QSM).

MATERIALS AND METHODS

Forty healthy controls and 40 AIS patients were recruited, and their QSM images were obtained. There were seven regions of interest (ROIs) in AIS patients, including the infarct regions of responsible arteries (R1), the non-infarct regions of responsible arteries (R2), the contralateral symmetrical sites of lesions (R3), and the non-responsible cerebral arterial regions (R4, R5, R6, R7). For the healthy controls, the cerebral arterial regions corresponding to the AIS patient group were selected as ROIs. The differences in corresponding ROI susceptibilities between AIS patients and healthy controls and the differences in susceptibilities between infarcted and non-infarct regions in AIS patients were compared.

RESULTS

The susceptibilities of infarct regions in AIS patients were significantly higher than those in healthy controls (p<0.0001). There was no significant difference in non-infarct regions between the two groups (p>0.05). The susceptibility of the infarct regions in AIS patients was significantly higher than those of the non-infarct region of responsible artery and non-responsible cerebral arterial regions (p<0.01).

CONCLUSIONS

Abnormal iron deposition detected by QSM in the infarct regions of AIS patients may not affect iron levels in the non-infarct regions of responsible arteries and normal cerebral arteries, which may open the door for potential new diagnostic and treatment strategies.

Ferroptosis and endoplasmic reticulum stress in ischemic stroke

Ferroptosis is a form of non-apoptotic programmed cell death, and its mechanisms mainly involve the accumulation of lipid peroxides, imbalance in the amino acid antioxidant system, and disordered iron metabolism. The primary organelle responsible for coordinating external challenges and internal cell demands is the endoplasmic reticulum, and the progression of inflammatory diseases can trigger endoplasmic reticulum stress. Evidence has suggested that ferroptosis may share pathways or interact with endoplasmic reticulum stress in many diseases and plays a role in cell survival. Ferroptosis and endoplasmic reticulum stress may occur after ischemic stroke. However, there are few reports on the interactions of ferroptosis and endoplasmic reticulum stress with ischemic stroke. This review summarized the recent research on the relationships between ferroptosis and endoplasmic reticulum stress and ischemic stroke, aiming to provide a reference for developing treatments for ischemic stroke.

Mechanisms of Ferritinophagy and Ferroptosis in Diseases

The discovery of the role of autophagy, particularly the selective form like ferritinophagy, in promoting cells to undergo ferroptosis has inspired us to investigate functional connections between diseases and cell death. Ferroptosis is a novel model of procedural cell death characterized by the accumulation of iron-dependent reactive oxygen species (ROS), mitochondrial dysfunction, and neuroinflammatory response. Based on ferroptosis, the study of ferritinophagy is particularly important. In recent years, extensive research has elucidated the role of ferroptosis and ferritinophagy in neurological diseases and anemia, suggesting their potential as therapeutic targets. Besides, the global emergence and rapid transmission of COVID-19, which is caused by SARS-CoV-2, represents a considerable risk to public health worldwide. The potential involvement of ferroptosis in the pathophysiology of brain injury associated with COVID-19 is still unclear. This review summarizes the pathophysiological changes of ferroptosis and ferritinophagy in neurological diseases, anemia, and COVID-19, and hypothesizes that ferritinophagy may be a potential mechanism of ferroptosis. Advancements in these fields will enhance our comprehension of methods to prevent and address neurological disorders, anemia, and COVID-19.

The role of ferroptosis and its mechanism in ischemic stroke

Ischemic stroke is an acute cerebrovascular disease with a high morbidity, mortality, and disability rate. Persistent ischemia of brain tissue can cause irreversible damage to neurons, leading to neurological dysfunction and seriously affecting patients' quality of life. However, current clinical therapies are limited and have not achieved satisfactory outcome, due to the incomplete understanding of the mechanism of neuronal damage during ischemic stroke. Recent studies have found that ferroptosis is implicated in the pathophysiology of ischemic stroke. Ferroptosis is an iron-dependent regulated cell death driven by lipid peroxidation. Under normal physiological conditions, GSH/GPX4, FSP1/CoQ10, GCH/BH4 and other anti-ferroptosis pathways can function effectively to suppress the occurrence of ferroptosis. After ischemic stroke, two typical ferroptosis characteristics, lipid peroxidation and iron accumulation, are observed, accompanied by changes in the expression of ferroptosis related genes such as GPX4, ACSL4, and SLC7A11, suggesting that ferroptosis plays a key role in ischemic stroke, which provides a new idea for the clinical treatment of ischemic stroke. This article reviewed the pathological mechanisms of ferroptosis in the occurrence and development of ischemic stroke, as well as the related progress of ferroptosis targeted therapy.

Causal Association of Iron Status With Functional Outcome After Ischemic Stroke

BACKGROUND

Iron status has been associated with functional outcomes after ischemic stroke (IS). Nonetheless, this association may be affected by confounders. We perform Mendelian randomization to clarify the causal association between iron status and functional outcome after IS.

METHODS

We obtained summary-level statistics related to iron status biomarkers from a meta-analysis of a gene-wide association study conducted by the Genetics of Iron Status Consortium, which included 11 discovery cohorts and 8 replication cohorts. We also took genetic variants related to 4 biomarkers of iron status from combining gene-wide association study results of Iceland, the United Kingdom, and Denmark to perform a replicate Mendelian randomization analysis. This data set included 4 iron status biomarkers, namely, ferritin, total iron binding capacity, iron, and transferrin saturation (TSAT). The confounders in these data sets have been adjusted to mitigate the collider bias. We acquired summary statistics data sets for functional outcomes following IS from the gene-wide association study meta-analysis conducted by the Genetics of Ischemic Stroke Functional Outcome Consortium. The genetic estimates for functional outcomes at 90 days after IS were evaluated by the modified Rankin Scale score, including 3741 cases with good functional outcomes (modified Rankin Scale score, 0-2) and 2280 subjects with poor functional outcomes poststroke (modified Rankin Scale score, 3-6). Inverse variance weighting was used as the primary method, complemented by sensitivity analyses for pleiotropy and increasing robustness.

RESULTS

Reported with odds ratios (ORs) of stroke outcome with per SD unit increase in genetically determined iron status biomarker, TSAT and iron were associated with poor functional outcome after IS (TSAT: OR, 1.36 [95% CI, 1.23-1.50]; P=2.27×10-9; iron: OR, 1.44 [95% CI, 1.13-1.85]; P=0.0033). In replicate Mendelian randomization analysis, the detrimental effects of iron on poor functional outcome after IS remained stable (OR, 1.60 [95% CI, 1.24-2.08]; P=0.0003). In the meta-analysis, iron and TSAT were associated with poor functional outcomes after IS (TSAT: ORmeta, 1.35 [95% CI, 1.23-1.48]; iron: ORmeta, 1.51 [95% CI, 1.27-1.81]). Through sensitivity analyses and reverse Mendelian randomization analyses, we confirmed the robustness of the results.

CONCLUSIONS

Our study provides evidence suggesting a potential causal relationship between iron status and poor functional outcomes after IS. Future studies are required to illuminate the underlying mechanism.

Protein Carbonylation Contributes to Prothrombotic Fibrin Clot Phenotype in Acute Ischemic Stroke: Clinical Associations

BACKGROUND

Acute ischemic stroke (AIS) is associated with enhanced oxidative stress and unfavorably altered fibrin clot properties. We investigated determinants of plasma protein carbonylation (PC) in AIS, its impact on the prothrombotic state, and prognostic value during follow-up.

METHODS

We included 98 consecutive AIS patients aged 74±12 years (male:female ratio, 50:48 [51%:49%]) at the Neurology Center in Warsaw, Poland, between January and December 2014. As many as 74 (75.5%) patients underwent thrombolysis, and 24 were unsuitable for thrombolysis. We determined plasma PC, along with thrombin generation, fibrin clot permeability, and clot lysis time on admission, at 24 hours, and 3 months. Stroke severity was assessed using the National Institutes of Health Stroke Scale and stroke outcome with the modified Rankin Scale. Hemorrhagic transformation was assessed on the computed tomography scan within 48 hours from the symptom onset, while stroke-related mortality was evaluated at 3 months.

RESULTS

On admission, PC levels (median, 4.61 [3.81-5.70] nM/mg protein) were associated with the time since symptom onset (r=0.41; P<0.0001) and with the National Institutes of Health Stroke Scale score (P=0.36; P=0.0003). Higher PC levels on admission correlated with denser fibrin clot formation and prolonged clot lysis time but not with thrombin generation. In thrombolysed patients, lower PC levels were observed after 24 hours (-34%) and at 3 months (-23%; both P<0.001). PC levels at baseline and after 24 hours predicted the modified Rankin Scale score >2 at 3 months (OR, 1.90 [95% CI, 1.21-3.00]; OR, 2.19 [95% CI, 1.39-3.44], respectively). Higher PC at baseline predicted hemorrhagic transformation of stroke (OR, 1.95 [95% CI, 1.02-3.74]) and stroke-related mortality (OR, 2.02 [95% CI, 1.08-3.79]), while higher PC at 24 hours predicted solely stroke-related mortality (OR, 2.11 [95% CI, 1.28-3.46]).

CONCLUSIONS

Elevated plasma PC levels in patients with AIS, related to prothrombotic fibrin clot properties, are associated with stroke severity. Thrombolysis reduces the extent of PC. The current study suggests a prognostic value of PC in AIS.

Neuroprotective Effects of Activin A against Cerebral Ischemia/Reperfusion Injury in Mice by Enhancing Nrf2 Expression to Attenuate Neuronal Ferroptosis

Activin A (Act A) is a member of the transforming growth factor-β (TGF-β) superfamily and can protect against ischemic cerebral injury. Ferroptosis, a newly discovered type of programmed cell death, contributes to the pathogenesis of cerebral ischemia-reperfusion injury (CIRI). However, little is known on whether Act A can modulate neuronal ferroptosis to protect against CIRI in a mouse model of middle cerebral artery occlusion (MCAO) and an HT22 cell model of oxygen-glucose deprivation/reoxygenation (OGD/R). The results indicated that Act A treatment relieved CIRI by improving neurological deficits and reducing the infarct volume in mice. MCAO stimulated iron accumulation and malondialdehyde formation and upregulated ACSL4 expression but downregulated GPX4 expression, a hallmark of ferroptosis in the brain of mice. Treatment with Act A significantly mitigated MCAO-triggered ferroptosis in the brain of mice. Furthermore, Act A treatment enhanced the MCAO-upregulated nuclear factor erythroid-2-related factor 2 (Nrf2) expression in the brains of mice. Similar results were observed in HT22 cells following OGD/R and pretreatment with Act A. The neuronal protective effect of Act A in HT22 cells was attenuated by treatment with ML385, an Nrf2 inhibitor. To conclude, Act A attenuated CIRI by enhancing Nrf2 expression and inhibiting neuronal ferroptosis.

Iron homeostasis imbalance and ferroptosis in brain diseases

Brain iron homeostasis is maintained through the normal function of blood-brain barrier and iron regulation at the systemic and cellular levels, which is fundamental to normal brain function. Excess iron can catalyze the generation of free radicals through Fenton reactions due to its dual redox state, thus causing oxidative stress. Numerous evidence has indicated brain diseases, especially stroke and neurodegenerative diseases, are closely related to the mechanism of iron homeostasis imbalance in the brain. For one thing, brain diseases promote brain iron accumulation. For another, iron accumulation amplifies damage to the nervous system and exacerbates patients' outcomes. In addition, iron accumulation triggers ferroptosis, a newly discovered iron-dependent type of programmed cell death, which is closely related to neurodegeneration and has received wide attention in recent years. In this context, we outline the mechanism of a normal brain iron metabolism and focus on the current mechanism of the iron homeostasis imbalance in stroke, Alzheimer's disease, and Parkinson's disease. Meanwhile, we also discuss the mechanism of ferroptosis and simultaneously enumerate the newly discovered drugs for iron chelators and ferroptosis inhibitors.

Induction Mechanism of Ferroptosis, Necroptosis, and Pyroptosis: A Novel Therapeutic Target in Nervous System Diseases

In recent years, three emerging cell deaths, ferroptosis, necroptosis and pyroptosis, have gradually attracted everyone's attention, and they also play an important role in the occurrence and development of various diseases. Ferroptosis is an idiographic iron-dependent form regulated cell death with the hallmark of accumulation of the intracellular reactive oxygen species (ROS). Necroptosis is a form of regulated necrotic cell death mediated by the receptor-interacting protein kinase 1(RIPK1) and receptor-interacting protein kinase 3RIPK3. Pyroptosis, also known as cell inflammatory necrosis, is a programmed cell necrosis mediated by Gasdermin D (GSDMD). It is manifested by the continuous swelling of the cells until the cell membrane ruptures, resulting in the release of the cell contents and the activation of a strong inflammatory response. Neurological disorders remain a clinical challenge and patients do not respond well to conventional treatments. Nerve cell death can aggravate the occurrence and development of neurological diseases. This article reviews the specific mechanisms of these three types of cell death and their relationship with neurological diseases and the evidence for the role of the three types of cell death in neurological diseases; understanding these pathways and their mechanisms is helpful for the treatment of neurological diseases.

Increased pulsatility index of the basilar artery is a risk factor for neurological deterioration after stroke: a case control study

Background

Higher pulsatility of the middle cerebral artery (MCA) is known to be associated with stroke progression. We investigated whether pulsatility index (PI) of the basilar artery (BA) can predict neurological deterioration (ND) after acute cerebral infarction.

Methods

A total of 708 consecutive patients with acute ischemic stroke who had undergone transcranial Doppler (TCD) ultrasonography were included. ND was defined as an increase in the National Institutes of Health Stroke Scale scores by two or more points after admission. The patients were categorized into quartiles according to BA PI. Multivariable logistic regression analysis was performed to examine whether BA PI is independently associated with ND.

Results

BA PI was well correlated with the right (n = 474, r² = 0.573, P < 0.001) by Pearson correlation analysis although MCA PI could not be measured from right MCA (n = 234, 33.05%) and left MCA (n = 252, 35.59%) by TCD owing to insufficient temporal bone window. Multivariable logistic regression analysis including age, sex, cerebral atherosclerosis burden, National Institutes of Health Stroke Scale at admission, and the proportion of patients with current smoking status, hypertension, diabetes mellitus, atrial fibrillation revealed that the higher BA PI (odds ratio, 3.28; confidence interval, 1.07–10.17; P = 0.038) was independently associated with ND.

Conclusions

BA PI, which would be identified regardless of temporal window, could predict ND among acute stroke patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40885-022-00210-9.

Carbohydrate based biomaterials for neural interface applications

Neuroprosthetic devices that record and modulate neural activities have demonstrated immense potential for bypassing or restoring lost neurological functions due to neural injuries and disorders. However, implantable electrical devices interfacing with brain tissue are susceptible to a series of inflammatory tissue responses along with mechanical or electrical failures which can affect the device performance over time. Several biomaterial strategies have been implemented to improve device-tissue integration for high quality and stable performance. Ranging from developing smaller, softer, and more flexible electrode designs to introducing bioactive coatings and drug-eluting layers on the electrode surface, such strategies have shown different degrees of success but with limitations. With their hydrophilic properties and specific bioactivities, carbohydrates offer a potential solution for addressing some of the limitations of the existing biomolecular approaches. In this review, we summarize the role of polysaccharides in the central nervous system, with a primary focus on glycoproteins and proteoglycans, to shed light on their untapped potential as biomaterials for neural implants. Utilization of glycosaminoglycans for neural interface and tissue regeneration applications is comprehensively reviewed to provide the current state of carbohydrate-based biomaterials for neural implants. Finally, we will discuss the challenges and opportunities of applying carbohydrate-based biomaterials for neural tissue interfaces.

Multimodal imaging of hemorrhagic transformation biomarkers in an ischemic stroke model

Hemorrhagic transformation of ischemic stroke has devastating consequences, with high mortality and poor functional outcomes. Animal models of ischemic stroke also demonstrate the potential for hemorrhagic transformation, which complicates biochemical characterization, treatment studies, and hinders poststroke functional outcomes in affected subjects. The incidence of hemorrhagic transformation of ischemic stroke in animal model research is not commonly reported. The postmortem brain of such cases presents a complex milieu of biomarkers due to the presence of healthy cells, regions of varying degrees of ischemia, dead and dying cells, dysregulated metabolites, and blood components (especially reactive Fe species released from lysed erythrocytes). To improve the characterization of hemorrhage biomarkers on an ischemic stroke background, we have employed a combination of histology, X-ray fluorescence imaging (XFI), and Fourier transform infrared (FTIR) spectroscopic imaging to assess 122 photothrombotic (ischemic) stroke brains. Rapid freezing preserves brain biomarkers in situ and minimizes metabolic artifacts due to postmortem ischemia. Analysis revealed that 25% of the photothrombotic models had clear signs of hemorrhagic transformation. The XFI and FTIR metabolites provided a quantitative method to differentiate key metabolic regions in these models. Across all hemorrhage cases, it was possible to consistently differentiate otherwise healthy tissue from other metabolically distinct regions, including the ischemic infarct, the ischemic penumbra, blood vessels, sites of hemorrhage, and a region surrounding the hemorrhage core that contained elevated lipid oxidation. Chemical speciation of deposited Fe demonstrates the presence of heme-Fe and accumulation of ferritin.

Risk factors for relapse and nomogram for relapse probability prediction in patients with minor ischemic stroke

BACKGROUND

The identification of risk factors for recurrence in patients with minor ischemic stroke (MIS) is a critical medical need.

AIM

To develop a nomogram for individualized prediction of in-hospital recurrence in MIS patients.

METHODS

Based on retrospective collection, a single-center study was conducted at the First Affiliated Hospital of Anhui Medical University from January 2014 to December 2019. Univariate and multivariate logistic regression analyses were used to determine the risk factors associated with MIS recurrence. The least absolute shrinkage and selection operator regression was performed for preliminary identification of potential risk factors. Uric acid, systolic blood pressure, serum total bilirubin (STBL), and ferritin were integrated for nomogram construction. The predictive accuracy and calibration of the nomogram model were assessed by the area under the receiver operating characteristic curve (AUC-ROC) and Hosmer-Lemeshow test, respectively.

RESULTS

A total of 2216 MIS patients were screened. Among them, 155 were excluded for intravascular therapy, 146 for unknown National Institutes of Health Stroke Scale score, 195 for intracranial hemorrhage, and 247 for progressive stroke. Finally, 1244 patients were subjected to further analysis and divided into a training set (n = 796) and a validation set (n = 448). Multivariate logistic regression analysis revealed that uric acid [odds ratio (OR): 0.997, 95% confidence interval (CI): 0.993-0.999], ferritin (OR: 1.004, 95%CI: 1.002-1.006), and STBL (OR: 0.973, 95%CI: 0.956-0.990) were independently associated with in-hospital recurrence in MIS patients. Our model showed good discrimination; the AUC-ROC value was 0.725 (95%CI: 0.646-0.804) in the training set and 0.717 (95%CI: 0.580-0.785) in the validation set. Moreover, the calibration between nomogram prediction and the actual observation showed good consistency. Hosmer-Lemeshow test results confirmed that the nomogram was well-calibrated (P = 0.850).

CONCLUSION

Our present findings suggest that the nomogram may provide individualized prediction of recurrence in MIS patients.

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.

Extracellular ferritin contributes to neuronal injury in an in vitro model of ischemic stroke

Previous clinical and experimental studies have shown that neurological decline and poor functional outcome after acute ischemic stroke in humans are associated with high ferritin levels in serum and cerebrospinal fluid (CSF) within 24 h of ischemic stroke onset. The aim of the present study was to find out if and how high extracellular ferritin concentrations can increase the excitotoxicity effect in a neuronal cortical culture model of stroke. Extracellular ferritin (100 ng/ml) significantly increased the excitotoxic effect caused by excessive exogenous glutamate (50 μM and 100 μM) by leading to an increase in lipid peroxidation, a reduction in mitochondrial membrane potential, and a decrease in neuron viability. Extracellular apoferritin (100 ng/ml), the iron-free form of the protein, does not increase the excitotoxicity of glutamate, which proves that iron was responsible for the neurotoxic effect of the exogenous ferritin. We present evidence that extracellular ferritin iron exacerbates the neurotoxic effect induced by glutamate excitotoxicity and that the effect of ferritin iron is dependent of glutamate excitotoxicity. Our results support the idea that body iron overload is involved in the severity of the brain damage caused by stroke and reveal the need to control systemic iron homeostasis.

Acute Stroke Biomarkers: Are We There Yet?

Background: Distinguishing between stroke subtypes and knowing the time of stroke onset are critical in clinical practice. Thrombolysis and thrombectomy are very effective treatments in selected patients with acute ischemic stroke. Neuroimaging helps decide who should be treated and how they should be treated but is expensive, not always available and can have contraindications. These limitations contribute to the under use of these reperfusion therapies.

Aim: An alternative approach in acute stroke diagnosis is to identify blood biomarkers which reflect the body's response to the damage caused by the different types of stroke. Specific blood biomarkers capable of differentiating ischemic from hemorrhagic stroke and mimics, identifying large vessel occlusion and capable of predicting stroke onset time would expedite diagnosis and increase eligibility for reperfusion therapies.

Summary of Review: To date, measurements of candidate biomarkers have usually occurred beyond the time window for thrombolysis. Nevertheless, some candidate markers of brain tissue damage, particularly the highly abundant glial structural proteins like GFAP and S100β and the matrix protein MMP-9 offer promising results. Grouping of biomarkers in panels can offer additional specificity and sensitivity for ischemic stroke diagnosis. Unbiased “omics” approaches have great potential for biomarker identification because of greater gene, protein, and metabolite coverage but seem unlikely to be the detection methodology of choice because of their inherent cost.

Conclusion: To date, despite the evolution of the techniques used in their evaluation, no individual candidate or multimarker panel has proven to have adequate performance for use in an acute clinical setting where decisions about an individual patient are being made. Timing of biomarker measurement, particularly early when decision making is most important, requires urgent and systematic study.

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.

Extract of Naotaifang, a compound Chinese herbal medicine, protects neuron ferroptosis induced by acute cerebral ischemia in rats

OBJECTIVE

Our previous research showed that Naotaifang (a compound traditional Chinese herbal medicine) extract (NTE) has clinically beneficial effects on neurological improvement of patients with acute cerebral ischemia. In this study, we investigated whether NTE protected acute brain injury in rats and whether its effects on ferroptosis could be linked to the dysfunction of glutathione peroxidase 4 (GPX4) and iron metabolism.

METHODS

We established an acute brain injury model of middle cerebral artery occlusion (MCAO) in rats, in which we could observe the accumulation of iron in neurons, as detected by Perl's staining. Using assay kits, we measured expression levels of ferroptosis biomarkers, such as iron, glutathione (GSH), reactive oxygen species (ROS) and malonaldehyde (MDA); further the expression levels of transferrin receptor 1 (TFR1), divalent metal transporter 1 (DMT1), solute carrier family 7 member 11 (SLC7A11) and GPX4 were determined using immunohistochemical analysis, real-time quantitative polymerase chain reaction and Western blot assays.

RESULTS

We found that treatment with NTE reduced the expression levels of TFR1 and DMT1, reduced ROS, MDA and iron accumulation and reduced neurobehavioral scores, relative to untreated MCAO rats. Treatment with NTE increased the expression levels of SLC7A11, GPX4 and GSH, and the number of Nissl bodies in the MCAO rats.

CONCLUSION

Taken together, our data suggest that acute cerebral ischemia induces neuronal ferroptosis and the effects of treating MCAO rats with NTE involved inhibition of ferroptosis through the TFR1/DMT1 and SCL7A11/GPX4 pathways.

Blood Biomarkers for Stroke Diagnosis and Management

Biomarkers are objective indicators used to assess normal or pathological processes, evaluate responses to treatment and predict outcomes. Many blood biomarkers already guide decision-making in clinical practice. In stroke, the number of candidate biomarkers is constantly increasing. These biomarkers include proteins, ribonucleic acids, lipids or metabolites. Although biomarkers have the potential to improve the diagnosis and the management of patients with stroke, there is currently no marker that has demonstrated sufficient sensitivity, specificity, rapidity, precision, and cost-effectiveness to be used in the routine management of stroke, thus highlighting the need for additional work. A better standardization of clinical, laboratory and statistical procedures between centers is indispensable to optimize biomarker performance. This review focuses on blood biomarkers that have shown promise for translation into clinical practice and describes some newly reported markers that could add to routine stroke care. Avenues for the discovery of new stroke biomarkers and future research are discussed. The description of the biomarkers is organized according to their expected application in clinical practice: diagnosis, treatment decision, and outcome prediction.

Iron Overload Exacerbates the Risk of Hemorrhagic Transformation After tPA (Tissue-Type Plasminogen Activator) Administration in Thromboembolic Stroke Mice

Background and Purpose- Recanalization with tPA (tissue-type plasminogen activator) is the only pharmacological therapy available for patients with ischemic stroke. However, the percentage of patients who may receive this therapy is limited by the risk of hemorrhagic transformation (HT)-the main complication of ischemic stroke. Our aim is to establish whether iron overload affects HT risk, to identify mechanisms that could help to select patients and to prevent this devastating complication. Methods- Mice fed with control or high-iron diet were subjected to thromboembolic stroke, with or without tPA therapy at different times after occlusion. Blood samples were collected for determination of malondialdehyde, matrix metalloproteinases, and fibronectin. Brain samples were collected 24 hours after occlusion to determine brain infarct and edema size, hemorrhage extension, IgG extravasation, and inflammatory and oxidative markers (neutrophil infiltration, 4-hydroxynonenal, and matrix metalloproteinase-9 staining). Results- Despite an increased rate of recanalization, iron-overload mice showed less neuroprotection after tPA administration. Importantly, iron overload exacerbated the risk of HT after early tPA administration, accelerated ischemia-induced serum matrix metalloproteinase-9 increase, and enhanced basal serum lipid peroxidation. High iron increased brain lipid peroxidation at most times and neutrophil infiltration at the latest time studied. Conclusions- Our data showing that iron overload increases the death of the compromised tissues, accelerates the time of tPA-induced reperfusion, and exacerbates the risk of HT may have relevant clinical implications for a safer thrombolysis. Patients with stroke with iron overload might be at high risk of HT after fibrinolysis, and, therefore, clinical studies must be performed to confirm our results.

Immune-inflammatory, oxidative stress and biochemical biomarkers predict short-term acute ischemic stroke death

The aim of the study was to define new immune-inflammatory, oxidative stress and biochemical biomarkers, which predict mortality within a period of 3 months after acute ischemic stroke (AIS). We recruited 176 healthy volunteers and 145 AIS patients, categorized as AIS survivors and non-survivors, and measured interleukin (IL)-6, high sensitivity C-reactive protein (hsCRP), ferritin, iron, total serum protein (TSP), erythrocyte sedimentation rate (ESR), white blood cells (WBC), 25 hydroxyvitamin D [25(OH)D], lipid hydroperoxides (CL-LOOH), insulin, glucose and high-density lipoprotein (HDL)-cholesterol. In patients, these biomarkers were measured within 24 h after AIS onset. We also computed two composite scores reflecting inflammatory indices, namely INFLAM index1 (sum of z scores of hsCRP+IL-6 + ferritin+ESR + WBC) and INFLAM index2 (z INFLAM index1 - z 25(OH)D - z iron + z TSP). Three months after AIS, non-survivors (n = 54) showed higher baseline levels of IL-6, hsCRP, ferritin and glucose and lower levels of HDL-cholesterol and 25(OH)D than survivors (n = 91). Non-survivors showed higher baseline ESR and lowered TSP than controls, while survivors occupied an intermediate position. Death after AIS was best predicted by increased IL-6, glucose, ferritin and CL-LOOH and lowered 25(OH)D levels. The area under the receiver operating curves computed on the INFLAM index1 and 2 scores were 0.851 and 0.870, respectively. In conclusion, activation of peripheral immune-inflammatory, oxidative and biochemical pathways is critically associated with mortality after AIS. Our results may contribute to identify new biomarker sets, which may predict post-stroke death, as well as suggest that IL-6 trans-signaling coupled with redox imbalances may be possible new targets in the prevention of short-term outcome AIS death.

Association between Striatal Brain Iron Deposition, Microbleeds and Cognition 1 Year After a Minor Ischaemic Stroke

Brain iron deposits (IDs) are inversely associated with cognitive function in community-dwelling older people, but their association with cognition after ischemic stroke, and whether that differs from microbleeds, is unknown. We quantified basal ganglia IDs (BGID) and microbleeds (BMBs) semi-automatically on brain magnetic resonance images from patients with minor stroke (NIHSS < 7), at presentation and 12 months after stroke. We administered the National Adult Reading Test (NART, estimates premorbid or peak adult cognition) and the Revised Addenbrooke's Cognitive Examination (ACE-R; current cognition) at 1 and 12 months after stroke. We adjusted analyses for baseline cognition, age, gender, white matter hyperintensity (WMH) volume and vascular risk factors. In 200 patients, mean age 65 years, striatal IDs and BMBs volumes did not change over the 12 months. Baseline BGID volumes correlated positively with NART scores at both times (ρ = 0.19, p < 0.01). Baseline and follow-up BGID volumes correlated positively with age (ρ = 0.248, p < 0.001 and ρ = 0.271, p < 0.001 respectively), but only baseline (and not follow-up) BMB volume correlated with age (ρ = 0.129, p < 0.05). Both smoking and baseline WMH burden predicted verbal fluency and visuospatial abilities scores (B = -1.13, p < 0.02 and B = -0.22, p = 0.001 respectively) at 12 months after stroke. BGIDs and BMBs are associated differently with cognition post-stroke; studies of imaging and post-stroke cognition should adjust for premorbid cognition. The positive correlation of BGID with NART may reflect the lower premorbid cognition in patients with stroke at younger vs older ages.

Diagnostics and Treatments of Iron-Related CNS Diseases

Iron has been proposed to be responsible for neuronal loss in several diseases of the central nervous system, including Alzheimer's disease (AD), Parkinson's disease (PD), stroke, Friedreich's ataxia (FRDA), multiple sclerosis (MS), amyotrophic lateral sclerosis (ALS). In many diseases, abnormal accumulation of brain iron in disease-affected area has been observed, without clear knowledge of the contribution of iron overload to pathogenesis. Recent evidences implicate that key proteins involved in the disease pathogenesis may also participate in cellular iron metabolism, suggesting that the imbalance of brain iron homeostasis is associated with the diseases. Considering the complicated regulation of iron homeostasis within the brain, a thorough understanding of the molecular events leading to this phenotype is still to be investigated. However, current understanding has already provided the basis for the diagnosis and treatment of iron-related CNS diseases, which will be reviewed here.

Frequency, Predictors, and Outcomes of Prehospital and Early Postarrival Neurological Deterioration in Acute Stroke: Exploratory Analysis of the FAST-MAG Randomized Clinical Trial

Importance

Studies of neurological deterioration in stroke have focused on the subacute period, but stroke treatment is increasingly migrating to the prehospital setting, where the neurological course has not been well delineated.

Objective

To describe the frequency, predictors, and outcomes of neurological deterioration among patients in the ultra-early period following ischemic stroke or intracranial hemorrhage.

Design, Settings, and Participants

Exploratory analysis of the prehospital, randomized Field Administration of Stroke Therapy-Magnesium (FAST-MAG) Trial conducted from 2005 to 2013 within 315 ambulances and 60 stroke patient receiving hospitals in Southern California. Participants were consecutively enrolled patients with suspected acute stroke who were transported by ambulance within 2 hours of stroke onset.

Main Outcomes and Measures

The main outcome was neurological deterioration, defined as a worsening of 2 or more points on the Glasgow Coma Scale (GCS), a level of consciousness scale ranging from 3 to 15, with higher scores indicating more alertness. Imaging outcomes were ischemic or hemorrhagic injury extent identified during the first brain imaging scan. Outcomes at 3 months included global disability level (assessed using the modified Rankin Scale [mRS]; range, 0-6, with higher numbers indicating greater disability) and mortality.

Results

Among the 1690 patients (99.4%), the mean (SD) age was 69.4 (13.5) years, and 43% were female. Final diagnoses were acute cerebral ischemia in 1237 patients (73.2%), intracranial hemorrhage in 386 patients (22.8%), and neurovascular mimic in 67 patients (4.0%). The median (interquartile range [IQR]) minutes between the last well-known time and GCS assessments were 23 (14-42) minutes for prehospital, 58 (46-79) minutes for ED arrival, and 149 (120-180) minutes for early ED course assessments. From prehospital to early postarrival, ultra-early neurological deterioration (U-END) occurred in 200 of 1690 patients (11.8%), more often among patients with intracranial hemorrhage than among those with acute cerebral ischemia (119 of 386 [30.8%] vs 75 of 1237 [6.1%], P < .001). Patterns of U-END were prehospital U-END without early recovery in 30 of 965 patients (3.1%), stable prehospital course but early ED deterioration in 49 of 965 patients (5.1%), and continuous deterioration in both prehospital and early ED phases in 27 of 965 patients (2.8%). Ultra-early neurological deterioration was associated with worse 3-month outcomes, including increased global disability (mRS score, 4.6 vs 2.4; P < .001), reduced functional independence (mRS score 0-2, 32 of 200 [16.0%] vs 844 of 1490 [56.6%]; P < .001), and increased mortality (87 of 200 [43.5%] vs 176 of 1490 [11.8%]; P < .001).

Conclusions and Relevance

Ultra-early neurological deterioration occurs in 1 in 8 ambulance-transported patients with acute cerebrovascular disease, including 1 in 3 patients with intracranial hemorrhage and 1 in 16 patients with acute cerebral ischemia, and is associated with markedly reduced functional independence and increased mortality. Averting U-END may be a target for future prehospital therapeutics.

Trial Registration

ClinicalTrials.gov Identifier: NCT00059332.

The Role of Serum Ferritin, Pro-Brain Natriuretic Peptide and Homocysteine Levels in Determining Ischaemic Stroke Subtype, Severity and Mortality

Background

In ischaemic stroke, there are many biochemical and immunological reactions secondary to a reduced cerebral blood flow. The purpose of this study is to investigate the correlation between stroke subtype, stroke severity, mortality, and serum ferritin, pro-brain natriuretic peptide (pro-BNP), homocysteine values before a specific treatment is given to stroke patients in the emergency department.

Methods

Consecutive acute ischaemic stroke patients admitted between December 2007 and April 2008 were enrolled into the study. Serum ferritin, pro-BNP and homocysteine levels were studied before specific treatment was carried out. Stroke subtypes were determined according to the Trial of Org 10172 in Acute Stroke Treatment (TOAST) and Oxfordshire Community Stroke Project (OCSP) criteria. The severity of stroke was determined by the National Institutes of Health Stroke Scale (NIHSS). Fifteen healthy individuals who matched the study group in terms of sex and age were chosen as control.

Results

Ninety-two patients were included in the study. There was a significant difference in the serum ferritin, pro-BNP and homocysteine levels between patients who died and those who survived (p=0.013, p<0.001 and p=0.003 respectively). Serum ferritin, pro-BNP and homocysteine levels were higher in all stroke subtypes than in the control group. Comparing among stroke subtypes, only serum pro-BNP levels were higher in the cardioembolic stroke group than in the atherothrombotic stroke and lacunar stroke groups (p=0.003 and p<0.001 respectively); and only serum pro-BNP levels were higher in the total anterior circulation infarct group than in the posterior circulation infarct and lacunar infarct groups (p=0.010 and p=0.017 respectively). Pro-BNP levels were significantly higher in patients with NIHSS score >15 than NIHSS=8-15 and NIHSS=1-7 (p=0.016 and p<0.001 respectively).

Conclusion

Ferritin, pro-BNP and homocysteine levels were raised in acute ischaemic stroke patients. However, only serum pro-BNP level is clinically useful in predicting stroke subtype, severity and mortality that could provide an insight to the choice of treatment.

Iron-loaded transferrin (Tf) is detrimental whereas iron-free Tf confers protection against brain ischemia by modifying blood Tf saturation and subsequent neuronal damage

Despite transferrin being the main circulating carrier of iron in body fluids, and iron overload conditions being known to worsen stroke outcome through reactive oxygen species (ROS)-induced damage, the contribution of blood transferrin saturation (TSAT) to stroke brain damage is unknown. The objective of this study was to obtain evidence on whether TSAT determines the impact of experimental ischemic stroke on brain damage and whether iron-free transferrin (apotransferrin, ATf)-induced reduction of TSAT is neuroprotective. We found that experimental ischemic stroke promoted an early extravasation of circulating iron-loaded transferrin (holotransferrin, HTf) to the ischemic brain parenchyma. In vitro, HTf was found to boost ROS production and to be harmful to primary neuronal cultures exposed to oxygen and glucose deprivation. In stroked rats, whereas increasing TSAT with exogenous HTf was detrimental, administration of exogenous ATf and the subsequent reduction of TSAT was neuroprotective. Mechanistically, ATf did not prevent extravasation of HTf to the brain parenchyma in rats exposed to ischemic stroke. However, ATf in vitro reduced NMDA-induced neuronal uptake of HTf and also both the NMDA-mediated lipid peroxidation derived 4-HNE and the resulting neuronal death without altering Ca²⁺-calcineurin signaling downstream the NMDA receptor. Removal of transferrin from the culture media or blockade of transferrin receptors reduced neuronal death. Together, our data establish that blood TSAT exerts a critical role in experimental stroke-induced brain damage. In addition, our findings suggest that the protective effect of ATf at the neuronal level resides in preventing NMDA-induced HTf uptake and ROS production, which in turn reduces neuronal damage.

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Blood TSAT is pivotal to determine neuronal fate in rat models of stroke

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During ischemia blood transferrin extravasates and accumulates in ischemic neurons.

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Increasing TSAT with holotransferrin (HTf) is detrimental in rat models of stroke.

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Decreasing TSAT with apotransferrin (ATf) is beneficial in rat models of stroke

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HTf promotes and ATf reduces ROS-, iron- and NMDAR-initiated ischemic neuronal death.

Progression in acute ischemic stroke: Is widespread atherosclerotic background a risk factor?

OBJECTIVES

In this study, we aimed to investigate the causes and conditions related with progression and outcome of progressive acute ischemic stroke.

PATIENTS AND METHODS

In this prospective study, a total of 78 acute ischemic stroke patients (32 males, 46 females; mean age 70±12.8 years; range 34 to 95 years) were included between February 2006 and October 2010. The patients were classified into two groups as those with and without progression according to the National Institute of Health Stroke Scale (NIHSS). Risk factors for ischemic stroke, stroke subtypes, and radiological investigations and prognosis were compared between the progressive and non-progressive patients.

RESULTS

Neurological deterioration occurred in 12 patients (15%). Progressive acute ischemic stroke patients had carotid stenosis compared to non-progressive patients (50% vs 19%), and ischemic cardiac disease (33% vs 6%) more common in the patients with progression. Mortality during hospital stay and long term-outcomes were similar between the groups.

CONCLUSION

Our study results suggest that widespread atherosclerotic diseases may induce neurological progression.

Serum trace elements are associated with hemostasis, lipid spectrum and inflammatory markers in men suffering from acute ischemic stroke

The primary objective of the study is investigation of the association between trace elements status and hemostasis, lipid spectrum and inflammatory markers in acute ischemic stroke (AIS). A total of 30 men suffering from AIS and 30 healthy controls were involved in the current survey. Blood count, serum lipid spectrum, complement components C4 and C3a, vascular endothelial growth factor (VEGF), S100B protein, NR2 antibodies (NR2Ab), and total antioxidant status (TAS), as well as plasma fibrinogen, and D-dimer levels and activated partial thromboplastin time (APTT) were assessed. Serum trace elements were analyzed using inductively coupled plasma mass spectrometry. AIS patients were characterized by significantly increased fibrinogen, D-dimer, TG, C3a, C4, NR2Ab, and VEGF levels. The leukocyte count, erythrocyte sedimentation rate and serum atherogenic index were also increased in stroke patients. Oppositely, TAS and APTT values, bleeding and blood coagulation time were decreased. AIS patients were characterized by significantly decreased serum Fe and Co concentrations, whereas the level of Cu, I, Li, Mn, Se, Zn, As, Pb, Ni, and especially V and B in serum was significantly increased. Serum V and B tightly correlated with the procoagulant state and inflammatory markers. Multiple regression analysis revealed a significant inverse association between serum Se levels and stroke markers after adjustment for covariates. Therefore, it is hypothesized that elements like vanadium and boron may be closely involved in stroke pathogenesis by modulation of hemostasis and inflammation, whereas the observed increase in Se levels may be considered as a compensatory reaction.

CYP Genetic Variants, CYP Metabolite Levels, and Neurologic Deterioration in Acute Ischemic Stroke in Chinese Population

BACKGROUND

The mechanisms of neurologic deterioration (ND) are not fully understood. The aim of the present study was to evaluate the relationship between CYP genetic variants and CYP metabolite levels with ND in acute ischemic stroke patients.

METHODS

Eleven single nucleotide polymorphisms (SNPs) of seven CYP genes were genotyped in 396 patients with acute ischemic stroke. The CYP plasma metabolite levels (20-hydroxyeicosatetraenoic acid [HETE], total epoxyeicosatrienoic acids [EETs], and dihydroxyeicosatrienoic acids [DiHETEs]) were also assessed. The primary outcome was ND within 10 days on admission. ND was defined as an increase of two or more points in the National Institutes of Health Stroke Scale score.

RESULTS

Among 396 patients, 101 patients (25.5%) experienced ND. The plasma levels of 20-HETE and DiHETEs were significantly higher and the EET levels were significantly lower in patients with ND compared to patients without ND. Univariate analyses revealed that old age, diabetes mellitus (DM), higher fasting glucose, and higher hemoglobin A1c (HbA1c) were associated with ND. CYP2C8 rs17110453 CC, EPHX2 rs751141 GG, and CYP4A11 rs9333025 GG were independently associated with ND after adjusting age, DM, fasting glucose, and HbA1c (odds ratio [OR]: 1.60, 95% confidence interval [CI]: 1.02-3.72; OR: 3.01, 95% CI: 1.29-7.13; OR: 2.75, 95% CI: 1.17-6.24, respectively). Also, these polymorphisms were associated with CYP metabolite levels in patients with ND.

CONCLUSIONS

ND is fairly common in acute ischemic stroke. Specific CYP gene SNPs are associated with CYP plasma metabolite levels, which may explain their associations with ND. Further studies are needed to validate our findings.

Iron in the Brain: An Important Contributor in Normal and Diseased States

Iron is essential for normal neurological function because of its role in oxidative metabolism and because it is a cofactor in the synthesis of neurotransmitters and myelin. In the past several years, there has been increased attention to the importance of oxidative stress in the central nervous system. Iron is the most important inducer of reactive oxygen species, therefore, the relation of iron to neurodegenerative processes is more appreciated today than it was a few years ago. Nevertheless, despite this increased attention and awareness, our knowledge of iron metabolism in the brain at the cellular and molecular levels is still limited. Iron is distributed in a heterogeneous fashion among the different regions and cells of the brain. This regional and cellular heterogeneity is preserved across many species. Brain iron concentrations are not static; they increase with age and in many diseases and decrease when iron is deficient in the diet. In infants and children, insufficient iron in the diet is associated with decreased brain iron and with changes in behavior and cognitive functioning. Abnormal iron accumulation in the diseased brain areas and, in some cases, alterations in iron-related proteins have been reported in many neurodegenerative diseases, including Hallervorden-Spatz syndrome, Alzheimer’s disease, Parkinson’s disease, and Friedreich’s ataxia. There is strong evidence for iron-mediated oxidative damage as a primary contributor to cell death in these disorders. Demyelinating diseases, such as multiple sclerosis, especially warrant study in relation to iron availability. Myelin synthesis and maintenance have a high iron requirement, thus, oligodendrocytes must have a relatively high and constant supply of iron. However, the high oxygen utilization, high density of lipids, and high iron content of white matter all combine to increase the risk of oxidative damage. We review here the current knowledge of the normal metabolism of iron in the brain and the suspected role of iron in neuropathology.

Blood biomarkers in the early stage of cerebral ischemia

In ischemic stroke patients, blood-based biomarkers may be applied for the diagnosis of ischemic origin and subtype, prediction of outcomes and targeted treatment in selected patients. Knowledge of the pathophysiology of cerebral ischemia has led to the evaluation of proteins, neurotransmitters, nucleic acids and lipids as potential biomarkers. The present report focuses on the role of blood-based biomarkers in the early stage of ischemic stroke-within 72h of its onset-as gleaned from studies published in English in such patients. Despite growing interest in their potential role in clinical practice, the application of biomarkers for the management of cerebral ischemia is not currently recommended by guidelines. However, there are some promising clinical biomarkers, as well as the N-methyl-d-aspartate (NMDA) peptide and NMDA-receptor (R) autoantibodies that appear to identify the ischemic nature of stroke, and the glial fibrillary acidic protein (GFAP) that might be able to discriminate between acute ischemic and hemorrhagic strokes. Moreover, genomics and proteomics allow the characterization of differences in gene expression, and protein and metabolite production, in ischemic stroke patients compared with controls and, thus, may help to identify novel markers with sufficient sensitivity and specificity. Additional studies to validate promising biomarkers and to identify novel biomarkers are needed.

The association between serum ferritin levels and post-stroke depression

BACKGROUND

Post-stroke depression (PSD) is a common neuropsychiatric affective disorder occurring after stroke. Elevated serum ferritin levels have been reported to contribute to depression. Our aim was to determine whether there is a relationship between serum ferritin levels and PSD.

METHODS

196 ischemic stroke patients were consecutively recruited within the first 24h of stroke onset and were followed up for 2 months. Serum ferritin levels were assayed by electrochemiluminescence immunoassay at hospital admission. Clinical depression was diagnosed according to DSM-IV criteria and a HAMD -17 score of ≥ 7. Meanwhile, 100 normal control subjects were also recruited.

RESULTS

We found that 56 stroke patients (28.6%) were diagnosed with PSD at two months. There was a significant intergroup difference in serum ferritin levels within 24h after admission (F=25.044, P<0.001). Serum ferritin levels were significantly higher at admission in PSD patients than in non-PSD patients and normal controls. There was a positive correlation between serum ferritin levels and hs-CRP at admission in PSD patients (r=0.129, P=0.042). In multivariate analyses, serum levels of ferritin ≥ 130.15 µg/L were independently associated with PSD at two months [odds ratio OR=5.388, 95%CI:1.725-16.829; P=0.004] after adjusting for all possible variables.

LIMITATIONS

We excluded patients with severe aphasia and with serious conditions.In addition, the information for dietary intake was not recorded, which may influence body iron stores.

CONCLUSION

Our findings show that elevated serum ferritin levels at admission are associated with PSD and may predict its development at 2 months post-stroke.

Inflammatory and metabolic markers and short-time outcome in patients with acute ischemic stroke in relation to TOAST subtypes

The aim of this study was to evaluate the association between inflammatory and metabolic markers and short-time outcome with acute ischemic stroke subtypes. A total of 121 patients was classified according to TOAST criteria, such as large artery atherosclerosis (LAAS), lacunar infarct (LAC), cardioembolic infarct (CEI), other determined etiology (ODE), and undetermined etiology (UDE). The functional impairment was evaluated within the first eight hours of stroke and the outcome after three-month follow-up using the modified Rankin Scale. Blood samples were obtained up to 24 h of stroke. Compared with 96 controls, patients with LAAS, CEI, and LAC subtypes showed higher levels of white blood cells, high-sensitivity C-reactive protein (hsCRP), interleukin 6 (IL-6), metalloproteinase 9 (MMP-9), glucose, and iron (p < 0.05); and lower high-density lipoprotein cholesterol (HDL-C) (p < 0.0001); platelets, insulin, insulin resistance, and homocysteine were higher in LAC (p < 0.0001); ferritin was higher in LAAS (p < 0.0001); and total cholesterol (TC) was lower in LAAS and CEI (p < 0.01). When stroke subtypes were compared, insulin was higher in LAAS vs. LAC and in LAC vs. CEI (p < 0.05); and TC was lower in LAAS vs. LAC (p < 0.05). Outcome and rate of mortality after three-month were higher in LAAS vs. LAC (p < 0.001 and p = 0.0391 respectively). The results underscored the important role of the inflammatory response and metabolic changes in the pathogenesis of ischemic stroke subtypes that might be considered on the initial evaluation of stroke patients to identify those that could benefit with individualized therapeutic strategies that taken into account these markers after acute ischemic event.

Brain tissue responses to neural implants impact signal sensitivity and intervention strategies

Implantable biosensors are valuable scientific tools for basic neuroscience research and clinical applications. Neurotechnologies provide direct readouts of neurological signal and neurochemical processes. These tools are generally most valuable when performance capacities extend over months and years to facilitate the study of memory, plasticity, and behavior or to monitor patients’ conditions. These needs have generated a variety of device designs from microelectrodes for fast scan cyclic voltammetry (FSCV) and electrophysiology to microdialysis probes for sampling and detecting various neurochemicals. Regardless of the technology used, the breaching of the blood–brain barrier (BBB) to insert devices triggers a cascade of biochemical pathways resulting in complex molecular and cellular responses to implanted devices. Molecular and cellular changes in the microenvironment surrounding an implant include the introduction of mechanical strain, activation of glial cells, loss of perfusion, secondary metabolic injury, and neuronal degeneration. Changes to the tissue microenvironment surrounding the device can dramatically impact electrochemical and electrophysiological signal sensitivity and stability over time. This review summarizes the magnitude, variability, and time course of the dynamic molecular and cellular level neural tissue responses induced by state-of-the-art implantable devices. Studies show that insertion injuries and foreign body response can impact signal quality across all implanted central nervous system (CNS) sensors to varying degrees over both acute (seconds to minutes) and chronic periods (weeks to months). Understanding the underlying biological processes behind the brain tissue response to the devices at the cellular and molecular level leads to a variety of intervention strategies for improving signal sensitivity and longevity.

Incidence, causes and predictors of neurological deterioration occurring within 24 h following acute ischaemic stroke: a systematic review with pathophysiological implications

Early neurological deterioration (END) following ischaemic stroke is a serious event with manageable causes in only a fraction of patients. The incidence, causes and predictors of END occurring within 24 h of acute ischaemic stroke (END24) have not been systematically reviewed. We systematically reviewed Medline and Embase from January 1990 to April 2013 for all studies on END24 following acute ischaemic stroke (<8 h from onset). We recorded the incidence and presumed causes of and factors associated with END24. Thirty-six studies were included. Depending on the definition used, the incidence of END24 markedly varied among studies. Using the most widely used change in National Institutes of Health Stroke Scale ≥4 definition, the pooled incidence was 13.8% following thrombolysis, ascribed to intracranial haemorrhage and malignant oedema each in ∼20% of these. As other mechanisms were rarely reported, in the majority no clear cause was identified. Few data on END24 occurring in non-thrombolysed patients were available. Across thrombolysed and non-thrombolysed samples, the strongest and most consistent admission predictors were hyperglycaemia, no prior aspirin use, prior transient ischaemic attacks, proximal arterial occlusion and presence of early CT changes, and the most consistent 24 h follow-up associated factors were no recanalisation/reocclusion, large infarcts and intracranial haemorrhage. Finally, END24 was strongly predictive of poor outcome. The above findings are discussed with emphasis on END without a clear mechanism. Data on incidence and predictors of the latter subtype is scarce, and future studies using systematic imaging protocols should address its underlying pathophysiology. This may in turn lead to rational preventative and therapeutic measures for this ominous event.

Mechanisms, predictors and clinical impact of early neurological deterioration: the protocol of the Trondheim early neurological deterioration study

Background

10-40% of patients with acute ischemic stroke (AIS) suffer an early neurological deterioration (END), which may influence their long term prognosis. Multiple definitions of END exist, even in recently published papers. In the search for causes, various biochemical, clinical, and imaging markers have been found to be associated to END after AIS in some but not in other studies.

The primary aim of this study is to assess the contribution of END to functional level at 3 months post stroke measured by modified Rankin Scale (mRS). Secondary aims are to identify factors and mechanisms associated with END and to define the prevalence, degree and timing of END in relation to stroke onset, and to compare Scandinavian Stroke Scale (SSS) and National Institute of Health Stroke Scale (NIHSS) based END-definitions.

We hypothesized that END detected by changes in NIHSS and SSS (according to previously published criteria) at a threshold of 2 points indicate worsened prognosis, and that SSS is not inferior to NIHSS in predicting such a change. We further hypothesized that clinical deterioration has several causes, including impaired physiological homeostasis, vascular pathology, local effects and reactions secondary to the ischemic lesion, along with biochemical disturbances.

Methods

Single-centre prospective observational study.

Participants: Previously at home-dwelling patients admitted to our stroke unit within 24 hours after ictus of AIS are included into the study, and followed for 3 months. They are managed according to current procedures and national guidelines. A total of 368 patients are included by the end of the enrolment period (December 31^st 2013), and the material will be opened for analysis by June 30^th 2014.

Frequent neurological assessments, continuous monitoring, and repeated imaging and blood samples are performed in all patients in order to test the hypotheses.

Discussion

Strengths and weaknesses of our approach, along with reasons for the methods chosen in this study are discussed.

A novel mouse model of penetrating brain injury

Penetrating traumatic brain injury (pTBI) has been difficult to model in small laboratory animals, such as rats or mice. Previously, we have established a non-fatal, rat model for pTBI using a modified air-rifle that accelerates a pellet, which hits a small probe that then penetrates the experimental animal’s brain. Knockout and transgenic strains of mice offer attractive tools to study biological reactions induced by TBI. Hence, in the present study, we adapted and modified our model to be used with mice. The technical characterization of the impact device included depth and speed of impact, as well as dimensions of the temporary cavity formed in a brain surrogate material after impact. Biologically, we have focused on three distinct levels of severity (mild, moderate, and severe), and characterized the acute phase response to injury in terms of tissue destruction, neural degeneration, and gliosis. Functional outcome was assessed by measuring bodyweight and motor performance on rotarod. The results showed that this model is capable of reproducing major morphological and neurological changes of pTBI; as such, we recommend its utilization in research studies aiming to unravel the biological events underlying injury and regeneration after pTBI.

Role of iron in ischemia-induced neurodegeneration: mechanisms and insights

Iron is an important micronutrient for neuronal function and survival. It plays an essential role in DNA and protein synthesis, neurotransmission and electron transport chain due to its dual redox states. On the contrary, iron also catalyses the production of free radicals and hence, causes oxidative stress. Therefore, maintenance of iron homeostasis is very crucial and it involves a number of proteins in iron metabolism and transport that maintain the balance. In ischemic conditions large amount of iron is released and this free iron catalyzes production of more free radicals and hence, causing more damage. In this review we have focused on the iron transport and maintenance of iron homeostasis at large and also the effect of imbalance in iron homeostasis on retinal and brain tissue under ischemic conditions. The understanding of the proteins involved in the homeostasis imbalance will help in developing therapeutic strategies for cerebral as well retinal ischemia.

Can high-sensitivity C-reactive protein and ferritin predict functional outcome in acute ischemic stroke? A prospective study

BACKGROUND

Inflammation may not only be the consequence of brain infarction but it may also contribute to ischemic damage. However, the role of inflammatory markers in predicting functional outcome in stroke remains controversial.

OBJECTIVE

This study was conducted to evaluate the predictive value of admission high-sensitivity C-reactive protein (hs-CRP) and ferritin levels for functional disability in patients with acute ischemic stroke at 3-month follow-up and investigate the relationship between inflammatory markers and subtypes, severity, and risk factors of ischemic stroke.

METHODS

Sixty-two patients were examined prospectively within 48 hours after onset of ischemic stroke. Plasma hs-CRP and ferritin measurements were obtained from patients within 48 hours after onset and at 3-month follow-up. Patients were divided into 2 groups based on the level of hs-CRP: elevated (serum hs-CRP ≥0.5 mg/dL) and normal (serum hs-CRP<0.5 mg/dL) hs-CRP groups. Stroke severity was analyzed by the National Institutes of Health Stroke Scale (NIHSS) and functional disability was assessed by the Functional Independence Measure (FIM) and Functional Ambulation Scale (FAS). Stroke subtypes were classified according to the Oxfordshire Community Stroke Project.

RESULTS

Except for the correlation between hs-CRP levels and FIM scores on admission, no significant correlation was found between laboratory markers and FIM, FAS, and NIHSS scores and stroke subtypes on admission and at 3-month follow-up (P ≯ .05).

CONCLUSION

This study revealed that neither hs-CRP nor ferritin levels could predict functional disability 3 months after stroke onset. FIM, FAS, and NIHSS scores were more useful in predicting functional outcome 3 months after stroke onset than the laboratory markers evaluated in this study.