Ischemic stroke, inflammation, iron overload - Connection to a hepcidin

An update on the role of ferroptosis in ischemic stroke: from molecular pathways to Neuroprotection

INTRODUCTION

Ischemic stroke (IS), a major cause of mortality and disability worldwide, remains a significant healthcare challenge due to limited therapeutic options. Ferroptosis, a distinct iron-dependent form of regulated cell death characterized by lipid peroxidation and oxidative stress, has emerged as a crucial mechanism in IS pathophysiology. This review explores the role of ferroptosis in IS and its potential for driving innovative therapeutic strategies.

AREA COVERED

This review delves into the practical implications of ferroptosis in IS, focusing on molecular mechanisms like lipid peroxidation, iron accumulation, and their interplay with inflammation, reactive oxygen species (ROS), and the Nrf2-ARE antioxidant system. It highlights ferroptotic proteins, small-molecule inhibitors, and non-coding RNA modulators as emerging therapeutic targets to mitigate neuroinflammation and neuronal cell death. Studies from PubMed (1982-2024) were identified using MeSH terms such as 'Ferroptosis' and 'Ischemic Stroke,' and only rigorously screened articles were included.

EXPERT OPINION

Despite preclinical evidence supporting the neuroprotective effects of ferroptosis inhibitors, clinical translation faces hurdles such as suboptimal pharmacokinetics and safety concerns. Advances in drug delivery systems, bioinformatics, and AI-driven drug discovery may optimize ferroptosis-targeting strategies, develop biomarkers, and improve therapeutic outcomes for IS patients.

Hepatocyte activation and liver injury following cerebral ischemia promote HMGB1-mediated hepcidin upregulation in hepatocytes and regulation of systemic iron levels

We previously reported that high mobility group box 1 (HMGB1), a danger-associated molecular pattern (DAMP), increases intracellular iron levels in the postischemic brain by upregulating hepcidin, a key regulator of iron homeostasis, triggering ferroptosis. Since hepatocytes are the primary cells that produce hepcidin and control systemic iron levels, we investigated whether cerebral ischemia induces hepcidin upregulation in hepatocytes. Following middle cerebral artery occlusion (MCAO) in a rodent model, significant liver injury was observed. This injury was evidenced by significantly elevated Eckhoff's scores and increased serum levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST). Additionally, total iron levels were significantly elevated in the liver, with intracellular iron accumulation detected in hepatocytes. Hepcidin expression in the liver, which is primarily localized in hepatocytes, increased significantly starting at 3 h after MCAO and continued to increase rapidly, reaching a peak at 24 h. Interestingly, HMGB1 levels in the liver were also significantly elevated after MCAO, with the disulfide form of HMGB1 being the major subtype. In vitro experiments using AML12 hepatocytes showed that recombinant disulfide HMGB1 significantly upregulated hepcidin expression in a Toll-like receptor 4 (TLR4)- and RAGE-dependent manner. Furthermore, treatment with a ROS scavenger and a peptide HMGB1 antagonist revealed that both ROS generation and HMGB1 induction contributed to hepatocyte activation and liver damage following MCAO-reperfusion. In conclusion, this study revealed that cerebral ischemia triggers hepatocyte activation and liver injury. HMGB1 potently induces hepcidin not only in the brain but also in the liver, thereby influencing systemic iron homeostasis following ischemic stroke.

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.

Crosstalk between autophagy and ferroptosis mediate injury in ischemic stroke by generating reactive oxygen species

Stroke represents a significant threat to global human health, characterized by high rates of morbidity, disability, and mortality. Predominantly, strokes are ischemic in nature. Ischemic stroke (IS) is influenced by various cell death pathways, notably autophagy and ferroptosis. Recent studies have increasingly highlighted the interplay between autophagy and ferroptosis, a process likely driven by the accumulation of reactive oxygen species (ROS). Post-IS, either the inhibition of autophagy or its excessive activation can escalate ROS levels. Concurrently, the interaction between ROS and lipids during ferroptosis further augments ROS accumulation. Elevated ROS levels can provoke endoplasmic reticulum stress-induced autophagy and, in conjunction with free iron (Fe2+), can trigger ferroptosis. Moreover, ROS contribute to protein and lipid oxidation, endothelial dysfunction, and an inflammatory response, all of which mediate secondary brain injury following IS. This review succinctly explores the mechanisms of ROS-mediated crosstalk between autophagy and ferroptosis and the detrimental impact of increased ROS on IS. It also offers novel perspectives for IS treatment strategies.

A New Perspective in the Treatment of Ischemic Stroke: Ferroptosis

Ischemic stroke is a common neurological disease. Currently, there are no Food and Drug Administration-approved drugs that can maximize the improvement in ischemic stroke-induced nerve damage. Hence, treating ischemic stroke remains a clinical challenge. Ferroptosis has been increasingly studied in recent years, and it is closely related to the pathophysiological process of ischemic stroke. Iron overload, reactive oxygen species accumulation, lipid peroxidation, and glutamate accumulation associated with ferroptosis are all present in ischemic stroke. This article focuses on describing the relationship between ferroptosis and ischemic stroke and summarizes the relevant substances that ameliorate ischemic stroke-induced neurological damage by inhibiting ferroptosis. Finally, the problems in the treatment of ischemic stroke targeting ferroptosis are discussed, hoping to provide a new direction for its treatment.

Association between dietary inflammatory index and Stroke in the US population: evidence from NHANES 1999-2018

BACKGROUND

There is an increasing awareness that diet-related inflammation may have an impact on the stroke. Herein, our goal was to decipher the association of dietary inflammatory index (DII) with stroke in the US general population.

METHODS

We collected the cross-sectional data of 44,019 participants of the National Health and Nutrition Examination Survey (NHANES) 1999-2018. The association of DII with stroke was estimated using weighted multivariate logistic regression, with its nonlinearity being examined by restricted cubic spline (RCS) regression. The least absolute shrinkage and selection operator (LASSO) regression was applied for identifying key stroke-related dietary factors, which was then included in the establishment of a risk prediction nomogram model, with the receiver operating characteristic (ROC) curve being built to evaluate its discriminatory power for stroke.

RESULTS

After confounder adjustment, the adjusted odds ratios (ORs) with 95% confidence intervals (CIs) for stroke across higher DII quartiles were 1.19 (0.94-1.54), 1.46 (1.16-1.84), and 1.87 (1.53-2.29) compared to the lowest quartile, respectively. The RCS curve showed a nonlinear and positive association between DII and stroke. The nomogram model based on key dietary factors identified by LASSO regression displayed a considerable predicative value for stroke, with an area under the curve (AUC) of 79.8% (78.2-80.1%).

CONCLUSIONS

Our study determined a nonlinear and positive association between DII and stroke in the US general population. Given the intrinsic limitations of cross-sectional study design, it is necessary to conduct more research to ensure the causality of such association.

HMGB1 induces hepcidin upregulation in astrocytes and causes an acute iron surge and subsequent ferroptosis in the postischemic brain

Dysregulation of brain iron levels causes functional disturbances and damages neurons. Hepcidin (a peptide hormone) plays a principal role in regulating intracellular iron levels by modulating ferroportin (FPN, the only known iron exporter) through triggering its internalization and lysosomal degradation. We observed a significant and rapid iron surge in the cortices of ischemic hemispheres at 3 h after cerebral ischemia (middle cerebral artery occlusion, MCAO) that was maintained until 4 d post-MCAO. We showed upregulation of hepcidin expression in the brain as early as 3 h post-MCAO, mainly in astrocytes, and significant hepcidin accumulation in serum from 6 h post-MCAO, and these inductions were maintained for 1 day and 7 days, respectively. High mobility group box 1 (HMGB1), a prototypic danger-associated molecular pattern, accumulates markedly after transient MCAO and plays critical roles in damage aggravation via its proinflammatory effects. Here, we demonstrated that treatment with recombinant HMGB1 stimulated astrocytes to induce hepcidin expression in a TLR4- and CXCR4-dependent manner. Furthermore, hepcidin-mediated intracellular iron accumulation in neurons was confirmed by an experiment using N-methyl-D-aspartate (NMDA)-conditioned medium-treated primary astrocytes and fresh primary cortical neurons treated with hepcidin-containing astrocyte-conditioned medium. Moreover, HMGB1-mediated local hepcidin upregulation and subsequent local iron surge were found to cause ferroptosis in the postischemic brain, which was suppressed by the functional blocking of HMGB1 using intranasally administered HMGB1 A box or anti-HMGB1 antibody. These findings show that HMGB1 serves as a ferroptosis inducer by upregulating hepcidin in astrocytes and thus aggravates acute damage in the postischemic brain.

Metabolomics: A useful tool for ischemic stroke research

Ischemic stroke (IS) is a multifactorial and heterogeneous disease. Despite years of studies, effective strategies for the diagnosis, management and treatment of stroke are still lacking in clinical practice. Metabolomics is a growing field in systems biology. It is starting to show promise in the identification of biomarkers and in the use of pharmacometabolomics to help patients with certain disorders choose their course of treatment. The development of metabolomics has enabled further and more biological applications. Particularly, metabolomics is increasingly being used to diagnose diseases, discover new drug targets, elucidate mechanisms, and monitor therapeutic outcomes and its potential effect on precision medicine. In this review, we reviewed some recent advances in the study of metabolomics as well as how metabolomics might be used to identify novel biomarkers and understand the mechanisms of IS. Then, the use of metabolomics approaches to investigate the molecular processes and active ingredients of Chinese herbal formulations with anti-IS capabilities is summarized. We finally summarized recent developments in single cell metabolomics for exploring the metabolic profiles of single cells. Although the field is relatively young, the development of single cell metabolomics promises to provide a powerful tool for unraveling the pathogenesis of IS.

Deep gray matters iron deposition is positively associated with white matter hyperintensity in hypertension

The association and underlying mechanisms between iron deposition and white matter hyperintensity (WMH) remain unclear. In this study, quantitative susceptibility mapping (QSM) was used to quantify deep gray matters iron deposition and to explore the association from both global and regional perspectives. A total of 84 patients with hypertension and 26 healthy controls underwent a strategically acquired gradient echo (STAGE) protocol, and the multi-echo data were used to reconstruct QSM images. The susceptibilities were used to describe iron content. Global region (RI) susceptibilities were measured in regions of interest, and age-related thresholds were used to determine high-iron content region (RII) susceptibilities. Compared with healthy controls, hypertension had higher total WMH scores and regional scores (all p = .001) and higher susceptibilities using the RI or RII analysis (all p < .05). In healthy controls, there was no significant association between susceptibilities and WMH scores. In hypertension, the susceptibilities of deep gray matters were positively correlated with WMH scores (RI analysis: right putamen; RII analysis: bilateral caudate nucleus head, putamen, red nucleus, substantia nigra, and dentate nucleus; age and education corrected p < .05). These findings suggest that iron deposition in deep gray matters was positively associated with WMH in hypertension, especially using the RII analysis.

Association Between the Serum Iron and Acute Cognitive Impairment After Stroke: A Cross-Sectional Study

BACKGROUND

Complications such as cognitive impairment are common in stroke victims. The goal of this study was to see if there was a link between blood iron levels and post-stroke cognitive impairment (PSCI) within 2 weeks after stroke.

METHODS

A total of 313 patients with ischemic stroke were recruited and separated into two groups: PSCI (n = 202) and non-PSCI (n = 111). The Mini-mental state examination scale was used to evaluate the cognitive status within 2 weeks after stroke (acute phase). The serum iron levels were divided into 4 layers: Q1 ≤ 11.7 μmol/L, Q2 11.8-15.1 μmol/, Q3 15.2-19.3 μmol/L, Q4 ≥ 19.4 μmol/L, respectively. The connection between serum iron and PSCI was then investigated further using binary logistic regression, which was adjusted for confounders.

RESULTS

The difference in serum iron levels between the PSCI and non-PSCI group was initially conducted by the Mann-Whitney test, and a significant difference was found (14.5 (11.0-17.8) vs. 16.9 (13.7-21.8), p < .001), with no confounders being adjusted. After adjusting for confounding factors, the binary regression analysis showed that the Q4 layer showed the lowest risk of PSCI, with the Q1 layer being the reference. (odds ratio (OR) = 0.297, 95% confidence interval (CI) = 0.136-0.649, p = 0.002).

CONCLUSION

A decreased risk of early-onset PSCI was linked to high serum iron levels. Low serum iron levels were found to be a risk factor for acute cognitive impairment following stroke, which could help physicians identify and take intervention measures early to reduce the risk of cognitive impairment after stroke.

Ferrostatin-1 alleviates cerebral ischemia/reperfusion injury through activation of the AKT/GSK3β signaling pathway

Ischemic stroke is the major cause of disability and death worldwide, but post-stroke neuronal death and related mechanisms remain unclear. Ferroptosis, a newly identified type of regulated cell death, has been shown to be associated with neurological disorders, yet the exact relationship between ferroptosis and ischemic stroke has not been elucidated. The purpose of this study is to investigate the effects of ferroptosis-specific inhibitor ferrostatin-1 (Fer-1) on neuronal injury after cerebral ischemia/reperfusion (I/R) and the underlying mechanism. In this study, we demonstrated that ferroptosis does occur in the stroke model. We found that Fer-1 reduced the levels of iron and malondialdehyde, and increased the content of glutathione and the expression of solute carrier family 7 member 11 and glutathione peroxidase 4 in cerebral I/R models. Additionally, Fer-1 significantly reduced the infarct volume and improved neurobehavioral outcomes. Moreover, we found that Fer-1 increased the levels of phosphorylated AKT and GSK3β following cerebral I/R. To further investigate the functional role of the AKT in the neuroprotective effects of Fer-1, MCAO models and oxygen-glucose deprivation-induced HT22 cells were pretreated with the AKT inhibitor MK-2206 before treatment with Fer-1 and the protective effects of Fer-1 were reversed. In conclusion, Fer-1 has protective effects on cerebral I/R injury by activating the AKT/GSK3β pathway, indicating that ferroptosis may become a novel target in the treatment of ischemic stroke.

Dynamic laboratory control of iron deficiency correction in neurosurgical patients

Introduction. The concept of blood management in relation to the surgical treatment of surgical diseases recommends the correction of iron defi ciency anemia (IDA) at the prehospital stage. However, surgery is often performed for emergency indications, making it necessary to carry out treatment as soon as possible.

Aim – to evaluate the possibilities of using delta hemoglobin (Delta-He) to monitor the effectiveness of IDA therapy in neurosurgical patients at the prehospital stage to reduce the time required to prepare patients for hospitalization.

Materials and methods. A total of 42 patients were treated with high-dose iron preparations (iron [III] carboxymaltosate and iron [III] hydroxide oligoisomaltosate). During the treatment, the dynamics of the number of reticulocytes and the values of the hemoglobin delta were evaluated. Data are presented as median (IQR).

Results. Treatment with high-dose iron preparations led to an increase in Delta-He values starting from days 1–2. Significant changes were recorded by days 3–4 from the start of therapy: from 2.2 (0.3–4.9) pg to 15.5 (13.8–10) pg on day 7. These changes were 2–3 days ahead of the increase in the number of reticulocytes in the corresponding blood samples: the number of reticulocytes significantly increased by days 5–6 from the start of treatment.

Conclusion. The use of high-dose preparations of iron [III] carboxymaltosate and iron [III] hydroxide oligoisomaltosate in the form of infusion made it possible to prepare neurosurgical patients for hospitalization within a week. None of the patients required transfusion of erythrocyte-containing components of donated blood at any stage of surgical treatment. The ability to focus on Delta-He values instead of the number of reticulocytes during iron therapy made it possible to shorten the waiting period for the effect of drug exposure by 2–3 days.

New insights in ferroptosis: Potential therapeutic targets for the treatment of ischemic stroke

Stroke is a common disease in clinical practice, which seriously endangers people's physical and mental health. The neurovascular unit (NVU) plays a key role in the occurrence and development of ischemic stroke. Different from other classical types of cell death such as apoptosis, necrosis, autophagy, and pyroptosis, ferroptosis is an iron-dependent lipid peroxidation-driven new form of cell death. Interestingly, the function of NVU and stroke development can be regulated by activating or inhibiting ferroptosis. This review systematically describes the NVU in ischemic stroke, provides a comprehensive overview of the regulatory mechanisms and key regulators of ferroptosis, and uncovers the role of ferroptosis in the NVU and the progression of ischemic stroke. We further discuss the latest progress in the intervention of ferroptosis as a therapeutic target for ischemic stroke and summarize the research progress and regulatory mechanism of ferroptosis inhibitors on stroke. In conclusion, ferroptosis, as a new form of cell death, plays a key role in ischemic stroke and is expected to become a new therapeutic target for this disease.

Potential application of traditional Chinese medicine in cerebral ischemia—Focusing on ferroptosis

Traditional Chinese medicine (TCM) has attracted a great deal of attention in the treatment of cerebral ischemia is credited with the remarkable neuroprotective effects. However, the imperfect functional mechanism of TCM is a major obstacle to their application. Many studies have been conducted to illustrate the pathophysiology of post-ischemic cerebral ischemia by elucidating the neuronal cell death pathway. Meanwhile, a new type of cell death, ferroptosis, is gradually being recognized in various diseases and is becoming a new pathway of therapeutic intervention strategy to solve many health problems. Especially since ferroptosis has been found to be closely involved into the pathogenesis of cerebral ischemia, it has been considered as a key target in the treatment of cerebral ischemia. Therefore, this paper reviews the latest research findings about the treatment of cerebral ischemia with TCM focused on ferroptosis as a target. Also, in order to explores the possibility of a new approach to treat cerebral ischemia with TCM, we discusses the correlation between ferroptosis and other cell death pathways such as apoptosis and autophagy, which would provide references for the following researches.

Urinary Proteome Analysis of Global Cerebral Ischemia-Reperfusion Injury Rat Model via Data-Independent Acquisition and Parallel Reaction Monitoring Proteomics

Cerebral ischemia–reperfusion (I/R) injury is the leading cause of death in severe hypotension caused by cardiac arrest, drowning, and excessive blood loss. Urine can sensitively reflect pathophysiological changes in the brain even at an early stage. In this study, a rat model of global cerebral I/R injury was established via Pulsinelli’s four-vessel occlusion (4-VO) method. Overall, 164 urinary proteins significantly changed in the 4-VO rat urine samples compared to the control samples by data-independent acquisition (DIA) proteomics technique (1.5-fold change, p < 0.05). Gene Ontology annotation showed that the acute-phase response, the ERK1 and ERK2 cascade, endopeptidase activity, blood coagulation, and angiogenesis were overrepresented. After parallel reaction monitoring (PRM) validation, 15 differential proteins having human orthologs were verified as the potential urinary markers associated with cerebral I/R injury. Of these potential biomarkers, 8 proteins were reported to be closely associated with cerebral I/R injury. Nine differential proteins changed even when there were no clinical manifestations or histopathological cerebral damage, including FGG, COMP, TFF2, HG2A, KNG1, CATZ, PTGDS, PRVA, and HEPC. These 9 proteins are potential biomarkers for early screening of cerebral I/R injury to prevent the development of cerebral injury. KNG1, CATZ, PTGDS, PRVA, and HEPC showed an overall trend of upregulation or downregulation at 12 and 48 h after I/R injury, reflecting the progression of cerebral I/R injury. These 5 proteins may serve as potential biomarkers for prognostic evaluation of cerebral I/R injury. These findings provide important clues to inform the monitoring of cerebral I/R injury and further the current understanding of its molecular biological mechanisms.

Ferroptosis—A Novel Mechanism With Multifaceted Actions on Stroke

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

[Delta-He a new biomarker for a surgical clinic]

BACKGROUND

Delta-He the difference between hemoglobin content in reticulocytes and erytrocytes is a relatively new laboratory indicator that is easily measured in everyday practice. This parameter is directly related to iron bioavailability for hemoglobin synthesis and can reflect various conditions accompanied by cytokine expression including systemic inflammation.

OBJECTIVE

To analyze the prospects for practical application of hemoglobin delta in assessment of neurosurgical patients throughout in-hospital treatment.

MATERIAL AND METHODS

We analyzed complete blood counts (Sysmex XN-1000 analyzer) with optical determination of reticulocyte hemoglobin and automatic calculation of Delta-He in 82 neurosurgical patients. Exclusion criteria were severe decompensated comorbidities, exacerbation of chronic infectious processes, cancer of other organs. Blood sampling for analysis of delta-hemoglobin was carried out before all diagnostic and therapeutic measures. Reference interval is indicated by the analyzer manufacturer as 1.7-4.4 pg.

RESULTS

Delta-He values at admission ranged from -1.8 to 6.1 pg. There was a consistent decrease of these values throughout 3-4 postoperative days. Then, the values could increase or continued to decrease. Increment of the index was noted in 76 patients (92.7%). Such dynamics was observed in case of uncomplicated postoperative period. Further decrease of Delta-He was observed in 6 patients (7.3%). These ones were characterized by a longer recovery after surgery, and the events required additional medical or surgical correction were recorded. Negative dynamics of Delta-He values could precede clinical manifestations of certain complication. Clarification of diagnosis and correction of therapy were accompanied by gradual increase of Delta-He values.

CONCLUSION

Estimation of Delta-He values over time can be used for monitoring of patients and effectiveness of therapy. From a practical point of view, it is important that examination can be performed at any time of the day.

Lipocalin 2 as a link between ageing, risk factor conditions and age-related brain diseases

Chronic (neuro)inflammation plays an important role in many age-related central nervous system (CNS) diseases, including Alzheimer's disease, Parkinson's disease and vascular dementia. Inflammation also characterizes many conditions that form a risk factor for these CNS disorders, such as physical inactivity, obesity and cardiovascular disease. Lipocalin 2 (Lcn2) is an inflammatory protein shown to be involved in different age-related CNS diseases, as well as risk factor conditions thereof. Lcn2 expression is increased in the periphery and the brain in different age-related CNS diseases and also their risk factor conditions. Experimental studies indicate that Lcn2 contributes to various neuropathophysiological processes of age-related CNS diseases, including exacerbated neuroinflammation, cell death and iron dysregulation, which may negatively impact cognitive function. We hypothesize that increased Lcn2 levels as a result of age-related risk factor conditions may sensitize the brain and increase the risk to develop age-related CNS diseases. In this review we first provide a comprehensive overview of the known functions of Lcn2, and its effects in the CNS. Subsequently, this review explores Lcn2 as a potential (neuro)inflammatory link between different risk factor conditions and the development of age-related CNS disorders. Altogether, evidence convincingly indicates Lcn2 as a key constituent in ageing and age-related brain diseases.

Glutamate, Glutamine, GABA and Oxidative Products in the Pons Following Cortical Injury and Their Role in Motor Functional Recovery

Brain injury leads to an excitatory phase followed by an inhibitory phase in the brain. The clinical sequelae caused by cerebral injury seem to be a response to remote functional inhibition of cerebral nuclei located far from the motor cortex but anatomically related to the injury site. It appears that such functional inhibition is mediated by an increase in lipid peroxidation (LP). To test this hypothesis, we report data from 80 rats that were allocated to the following groups: the sham group (n = 40), in which rats received an intracortical infusion of artificial cerebrospinal fluid (CSF); the injury group (n = 20), in which rats received CSF containing ferrous chloride (FeCl₂, 50 mM); and the recovery group (n = 20), in which rats were injured and allowed to recover. Beam-walking, sensorimotor and spontaneous motor activity tests were performed to evaluate motor performance after injury. Lipid fluorescent products (LFPs) were measured in the pons. The total pontine contents of glutamate (GLU), glutamine (GLN) and gamma-aminobutyric acid (GABA) were also measured. In injured rats, the motor deficits, LFPs and total GABA and GLN contents in the pons were increased, while the GLU level was decreased. In contrast, in recovering rats, none of the studied variables were significantly different from those in sham rats. Thus, motor impairment after cortical injury seems to be mediated by an inhibitory pontine response, and functional recovery may result from a pontine restoration of the GLN-GLU-GABA cycle, while LP may be a primary mechanism leading to remote pontine inhibition after cortical injury.

Cross Talk Between Ferroptosis and Cerebral Ischemia

Recently, ferroptosis has been revealed as a new form of regulated cell death. Distinct from apoptosis and necrosis, ferroptosis is evoked by iron-dependent lipid peroxidation. Furthermore, the metabolism of iron, lipids, and amino acids plays a significant regulatory role in ferroptosis, which can be reversed by glutathione peroxidase 4 and ferroptosis suppressor protein 1. Ferroptosis is implicated in the onset and development of numerous neurological diseases. Emerging studies have reported that ferroptosis induces and aggravates brain tissue damage following cerebral ischemia, whereas inhibition of ferroptosis dramatically attenuates induced damage. In this review, we have summarized the mechanistic relationship between ferroptosis and cerebral ischemia, including through iron overload, downregulation of glutathione peroxidase 4, and upregulation of lipid peroxidation. Although considerable attention has been paid to the effect of ferroptosis on cerebral ischemic injury, specific mechanisms need to be experimentally confirmed, including how cerebral ischemia induces ferroptosis and how ferroptosis deteriorates cerebral ischemia.

The Emerging Roles of Ferroptosis in Vascular Cognitive Impairment

Vascular cognitive impairment (VCI) is a clinical syndrome that encompasses all forms of cognitive deficits caused by cerebrovascular disease, from mild cognitive impairment to dementia. Vascular dementia, the second most common type of dementia after Alzheimer’s disease (AD), accounts for approximately 20% of dementia patients. Ferroptosis is a recently defined iron-dependent form of cell death, which is distinct from apoptosis, necrosis, autophagy, and other forms of cell death. Emerging evidence suggests that ferroptosis has significant implications in neurological diseases such as stroke, traumatic brain injury, and AD. Additionally, ferroptosis inhibition has an obvious neuroprotective effect and ameliorates cognitive impairment in various animal models. Here, we summarize the underlying mechanisms of ferroptosis and review the close relationship between ferroptosis and VCI.

No effects without causes: the Iron Dysregulation and Dormant Microbes hypothesis for chronic, inflammatory diseases

Since the successful conquest of many acute, communicable (infectious) diseases through the use of vaccines and antibiotics, the currently most prevalent diseases are chronic and progressive in nature, and are all accompanied by inflammation. These diseases include neurodegenerative (e.g. Alzheimer's, Parkinson's), vascular (e.g. atherosclerosis, pre-eclampsia, type 2 diabetes) and autoimmune (e.g. rheumatoid arthritis and multiple sclerosis) diseases that may appear to have little in common. In fact they all share significant features, in particular chronic inflammation and its attendant inflammatory cytokines. Such effects do not happen without underlying and initially 'external' causes, and it is of interest to seek these causes. Taking a systems approach, we argue that these causes include (i) stress-induced iron dysregulation, and (ii) its ability to awaken dormant, non-replicating microbes with which the host has become infected. Other external causes may be dietary. Such microbes are capable of shedding small, but functionally significant amounts of highly inflammagenic molecules such as lipopolysaccharide and lipoteichoic acid. Sequelae include significant coagulopathies, not least the recently discovered amyloidogenic clotting of blood, leading to cell death and the release of further inflammagens. The extensive evidence discussed here implies, as was found with ulcers, that almost all chronic, infectious diseases do in fact harbour a microbial component. What differs is simply the microbes and the anatomical location from and at which they exert damage. This analysis offers novel avenues for diagnosis and treatment.

Iron status in the elderly: A review of recent evidence

A comprehensive literature review of iron status in the elderly was undertaken in order to update a previous review (Fairweather-Tait et al, 2014); 138 summarised papers describe research on the magnitude of the problem, aetiology and age-related physiological changes that may affect iron status, novel strategies for assessing iron status with concurrent health conditions, hepcidin, lifestyle factors, iron supplements, iron status and health outcomes (bone mineral density, frailty, inflammatory bowel disease, kidney failure, cancer, cardiovascular, and neurodegenerative diseases). Each section of this review concludes with key points from the relevant papers. The overall findings were that disturbed iron metabolism plays a major role in a large number of conditions associated with old age. Correction of iron deficiency/overload may improve disease prognosis, but diagnosis of iron deficiency requires appropriate cut-offs for biomarkers of iron status in elderly men and women to be agreed. Iron deficiency (with or without anemia), anemia of inflammation, and anemia of chronic disease are all widespread in the elderly and, once identified, should be investigated further as they are often indicative of underlying disease. Management options should be reviewed and updated, and novel therapies, which show potential for treating anemia of inflammation or chronic disease, should be considered.

Hepcidin, an emerging and important player in brain iron homeostasis

Hepcidin is emerging as a new important factor in brain iron homeostasis. Studies suggest that there are two sources of hepcidin in the brain; one is local and the other comes from the circulation. Little is known about the molecular mediators of local hepcidin expression, but inflammation and iron-load have been shown to induce hepcidin expression in the brain. The most important source of hepcidin in the brain are glial cells. Role of hepcidin in brain functions has been observed during neuronal iron-load and brain hemorrhage, where secretion of abundant hepcidin is related with the severity of brain damage. This damage can be reversed by blocking systemic and local hepcidin secretion. Studies have yet to unveil its role in other brain conditions, but the rationale exists, since these conditions are characterized by overexpression of the factors that stimulate brain hepcidin expression, such as inflammation, hypoxia and iron-overload.

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.

New Insights into the Crosstalk between NMDARs and Iron: Implications for Understanding Pathology of Neurological Diseases

Both iron dyshomeostasis and N-methyl-D-aspartate receptors (NMDARs)-mediated neurotoxicity have been shown to have an important role in neurological diseases such as Parkinson’s disease (PD) and Alzheimer’s disease (AD). Evidence proved that activation of NMDARs could promote iron overload and iron-induced neurotoxicity by enhancing iron importer divalent metal transporter 1 (DMT1)-mediated iron uptake and iron releasing from lysosome. Also, iron overload could regulate NMDARs-mediated synaptic transmission. This indicates that there might be a possible relationship between iron and activation of NMDARs in neurological diseases. Understanding this interaction between iron and activation of NMDARs may provide new therapeutic avenues for a more targeted neurotherapeutic strategy for these diseases. Therefore, in this review article, we will describe the dysfunction of iron metabolism and NMDARs in neurological diseases including PD and AD, and summarize the new insight into the mechanisms underlying the interaction between iron and activation of NMDARs.

Clinical significance of serum hepcidin in patients with acute pancreatitis

AIM: To investigate the changes of serum hepcidin in patients with acute pancreatitis and analyze its clinical significance.

METHODS: Blood samples from 104 patients with mild acute pancreatitis, 45 patients with severe acute pancreatitis and 50 healthy controls were collected, and serum hepcidin was measured by enzyme linked immunosorbent assay at admission, 1, 3, and 7 d after admission. The association of serum hepcidin with acute pancreatitis was analyzed. Receiver operating characteristic curve analysis was performed.

RESULTS: The median concentration of serum hepcidin in patients with acute pancreatitis at admission was significantly higher than that in healthy controls (P < 0.05). The differences in median concentrations of serum hepcidin between severe and mild acute pancreatitis were significant at 1, 3, and 7 d after admission (P < 0.05), but not at admission. Correlation analysis showed that serum hepcidin was positively correlated with C-reactive protein levels and APACHE-II score (P = 0.004, 0.000), but was negatively correlated with serum calcium levels (P = 0.003). The area under the ROC curve of serum hepcidin in patients with severe acute pancreatitis and mild acute pancreatitis at 3 d after admission was 0.802. With a cutoff value of 133 ng/mL, the overall sensitivity was 95.6%, and specificity was 61.5%.

CONCLUSION: Serum hepcidin correlates with the extent of pancreatitis. It can be used for monitoring the development of acute pancreatitis and may be a potential marker for early diagnosis of severe acute pancreatitis.