Oxidative stress as a bridge between age and stroke: A narrative review

Yinaoxin granule alleviates cerebral ischemia-reperfusion injury by ferroptosis inhibition through Nrf2 pathway activation

BACKGROUND

Lipid peroxide accumulation plays significant roles in cerebral ischemia-reperfusion injury (CIRI) through various mechanisms, including ferroptosis. Preserving the neuronal metabolic equilibrium and averting cell death during cerebral ischemia-reperfusion are pivotal for protecting brain function. Yinaoxin granule (YNX) is a widely used Chinese herbal preparations for treating cerebrovascular diseases, but pharmacological mechanism remains ambiguous..

PURPOSE

The aim in this study was to assess the effectiveness of YNX in treating CIRI and to investigate the underlying mechanisms.

METHODS

The active ingredients of YNX were quantified using high-performance liquid chromatography. To explore the effects of YNX on CIRI and ferroptosis, both an in vitro oxygen-glucose deprivation and reperfusion model and a middle cerebral artery occlusion and reperfusion rat model were used. To assess the neuroprotective effects of YNX in the latter, neurological scores and cerebral blood flow were evaluated. Neuronal damage was determined through 2,3,5-triphenyltetrazolium chloride, Nissl, and H&E staining. Ferroptosis-related markers, including ferrous ion, glutathione, 4-hydroxynonenal, and malondialdehyde were also investigated. Furthermore, the gene expression and protein levels of solute carrier family 7 member 11 (SLC7A11), glutathione peroxidase 4 (GPX4) and glutamate-cysteine ligase modulator (GCLM) were determined.

RESULTS

YNX enhanced neurological scores and cerebral blood flow, reduced infarct volume, and rescued necrotic neurons in rats. Additionally, YNX mitigated lipid peroxidation and upregulated the SLC7A11, GCLM, and GPX4 levels. The absence of Nrf2 rendered neurons more susceptible to ischemia-reperfusion damage and abrogated the anti-ferroptotic neuroprotective effects of YNX.

CONCLUSION

YNX activates the Nrf2 pathway, resulting in the transcription of genes associated with antioxidants, including SLC7A11, GCLM, and GPX4. This suggests that YNX reduces lipid peroxidation and alleviates ferroptosis-induced CIRI.

Protective effects of cedrol against transient global cerebral ischemia/reperfusion injury in rat

BACKGROUND

The natural compound cedrol possess anti-inflammatory and antioxidant properties. We sought to assess the neuroprotective effect of cedrol in an animal model of transient global ischemia/reperfusion (I/R) injury.

METHOD

To induce transient global cerebral I/R injury, bilateral carotid arteries were temporarily occluded for 20 min. A total of 40 male Wistar rats were randomly divided in to 5 groups; The control and global I/R groups, and the treatment groups that received cedrol at doses of 7.5, 15, and 30 mg/kg/day for a week, following the global I/R induction. The passive avoidance test was used for assessing memory function, and then hippocampal tissues were collected to assess levels of malondialdehyde (MDA), total thiol, nitric oxide (NO), and the activity of superoxide dismutase (SOD), along with the concentration of brain-derived neurotrophic factor (BDNF).

RESULT

Our findings revealed that global I/R injury impaired rats' performance in the passive avoidance test and increased levels of MDA and NO. Moreover, it decreased the total thiol level, SOD activity, and BDNF level in the hippocampus. Administration of cedrol significantly improved memory function, reduced oxidative stress, NO level and increased BDNF level in the hippocampus.

CONCLUSION

The results indicate that cedrol has neuroprotective properties in global I/R by reducing oxidative stress and enhancing the levels of BDNF.

Microvascular Dysfunction, Mitochondrial Reprogramming, and Inflammasome Activation as Critical Regulators of Ischemic Stroke Severity Induced by Chronic Exposure to Prescription Opioids

The opioid epidemic endangers not only public health but also social and economic welfare. Growing clinical evidence indicates that chronic use of prescription opioids may contribute to an elevated risk of ischemic stroke and negatively impact poststroke recovery. In addition, NLRP3 inflammasome activation has been related to several cerebrovascular diseases, including ischemic stroke. Interestingly, an increase in NLRP3 inflammasome activation has also been reported in chronic opioid exposure. Given the pivotal roles of the blood-brain barrier (BBB) and oxidative stress in ischemic stroke pathophysiology, this study focuses on the impact of chronic exposure to prescription opioids on the integrity of cerebrovascular microvasculature, endothelial mitochondrial homeostasis, and the outcomes of ischemic stroke in male wild-type and NLRP3-deficient mice. Our results demonstrate that chronic opioid exposure can compromise the integrity of the BBB and elevate the generation of reactive oxygen species (ROS), resulting in endothelial mitochondrial dysfunction and apoptosis activation. We also provide evidence that opioid exposure enhances inflammasome activation and inflammatory responses and increases the severity of an ischemic stroke. The antioxidant N-acetylcysteine ameliorated these opioid-induced alterations and accelerated the poststroke tissue restoration and functional recovery processes in opioid-exposed mice. Importantly, there was also a significant decrease in ischemic stroke damage in the NLRP3-deficient mice with chronic opioid exposure as compared with wild-type controls. These findings indicate that chronic exposure to prescription opioids impacts the outcome of ischemic stroke by damaging microvascular cerebral integrity through inflammasome activation and mitochondrial dysfunction.

Drug screening for ischemic stroke using larvae and adult zebrafish model: a review

Ischemic stroke (IS) is the most recorded case of stroke that is caused by decreased blood flow to the brain. Nowadays, therapeutical agents for IS are limited and they have not shown maximum clinical results. Therefore, the exploration of new candidates for IS treatment continues to be done. Zebrafish as one of the animal models has its advantages and currently is being developed to be incorporated into the drug discovery pipeline of IS. This review explores the latest applications of the zebrafish model in screening potential therapeutic agents for IS. Key factors related to the experimental design such as developmental stage and strain, routes of drug administration, induction methods, and experimental parameters are also elaborated. Finally, this review offers future recommendations for the use of zebrafish in the pre-clinical study of IS. This review is beneficial as a reference for establishing drug screening protocols using the zebrafish IS model.

Effect of galangin on oxidative stress, antioxidant defenses and mitochondrial dynamics in a rat model of focal cerebral ischemia

Focal ischemia occurs when a cerebral artery becomes obstructed by an embolus or thrombus, leading to a rapid reduction in cerebral blood flow and significantly increasing the risk of mortality and disability. This condition is of particular concern in developing countries, where its prevalence is on the rise. Galangin, a flavonoid found in Alpinia officinarum, shows strong antioxidant, anti-inflammatory and anti-apoptotic properties. Its wide-ranging bioactivity in both in vitro and animal studies points to promising therapeutic applications. Given the role of oxidative stress in the pathophysiology of focal ischemia, the present study explored the effects of galangin on oxidative stress markers and antioxidant defenses in an animal model of the disease. A total of 60 healthy male Wistar rats were randomly assigned to six groups: Control, right middle cerebral artery occlusion (Rt.MCAO) + vehicle, Rt.MCAO + piracetam, and Rt.MCAO + galangin at doses of 25, 50 and 100 mg/kg body weight. The results indicated that 7 days of galangin treatment reduces infarct volume, malondialdehyde levels, and the density ratio of mitogen-activated protein kinase, while enhancing catalase, glutathione peroxidase and superoxide dismutase activities, and improving the density ratio of mitofusin 2 protein in the cortex and hippocampus. In conclusion, galangin showed significant in vivo potential in mitigating the pathological changes caused by cerebral ischemia, likely due to its antioxidant properties and modulation of mitochondrial dynamics. Additional research is now needed to explore the biochemical and neurological impacts of galangin in focal cerebral ischemia and to fully elucidate its mechanism of action.

Chitosan-Based Nanocapsules as a Delivery System of Hydrophobic Carnosic Acid, A Model Neuroprotective Drug

Introduction

Since the population of Europe is rapidly aging, the number of cases of neurodegenerative diseases sharply increases. One of the most significant limitations of current neurodegenerative disease treatment is the inefficient delivery of neuroprotective drugs to the affected part of the brain. One of the promising methods to improve the pharmacokinetic and pharmacodynamic properties of antioxidants is their encapsulation in nanocarriers.

Materials and Methods

Encapsulation of carnosic acid into a chitosan-based nanoparticle system with ultrasound-assisted emulsification process was developed. The physicochemical properties (size, stability, concentration of nanoparticles) of obtained nanocapsules were analyzed. Also, the cytotoxicity and neuroprotective effect in SH-SY5Y cells exposed to toxic concentration of H2O2 of the obtained nanoparticles were evaluated in vitro.

Results and Discussion

The capsules with diameters between 90 and 150 nm and long-term stability were obtained. Cytotoxicity tests of empty capsules indicate that observed toxic effects were concentration dependent and lower concentrations (dilution above 500×) can be considered as safe for tested cells. Our study also indicates that encapsulation of carnosic acid decreased the cytotoxicity of empty nanocapsules and can efficiently protect SH-SY5Y cells from factors causing cell destruction. In addition, the neuroprotective efficacy of carnosic acid loaded nanocapsules was also demonstrated in SH-SY5Y cells exposed to toxic concentration of H2O2. The designed nanoparticles appear to possess sufficient biocompatibility to deserve their further evaluation in in vivo models.

Reduced ischemia-reperfusion oxidative stress injury by melatonin and N-acetylcysteine in the male rat brain

Middle cerebral artery occlusion (MCAO) is a model for inducing ischemic stroke in rodents, leading to devastating brain damage. Oxidative stress (OS) plays a crucial role in the pathogenesis of ischemia. In this study, the effect of melatonin and N-acetylcysteine on ischemia-reperfusion-induced oxidative stress injury in the cerebral cortex of male rats was investigated. 30 male Wistar rats were divided into sham, ischemic, NAC, melatonin and NAC + melatonin groups. All groups, except the sham group, underwent MCAO on the left side, and the treatment groups received intraperitoneal injections of either 50 mg/kg N-acetylcysteine (NAC) or 5 mg/kg melatonin or a combination of both 24 and 48 hours later. At 24 and 72 hours after surgery, the animals were examined for sensory and motor activity. The cerebral cortex was dissected after sacrificing the rats, infarct volume estimated and the concentrations of glutathione peroxidase (GPx), superoxide dismutase (SOD), catalase (CAT), malondialdehyde (MDA) and nuclear factor erythroid-2 related factor 2 (Nrf2) were analyzed by enzyme-linked immunosorbent assay (ELISA). The results indicate that the NAC + melatonin group exhibited elevated sensory-motor activity and a reduced infarct volume rate in comparison to the ischemic group (p≤ 0.05). Compared to the ischemic group, the NAC + melatonin group showed a significant increase in SOD concentration and a significant decrease in MDA (p≤ 0.05). It can therefore be concluded that the simultaneous administration of NAC and melatonin can reduce the cerebral infarction volume, and improve neurological functions by modulating SOD and MDA.

A Novel Supplement Consisting of Rice, Silkworm Pupae and a Mixture of Ginger and Holy Basil Improves Post-Stroke Cognitive Impairment

Backgrounds/Objectives: Despite the increasing importance of the condition of post-stroke cognitive impairment (PSCI), the current therapy efficacy is limited. Since oxidative stress and inflammation are targeted in anti-stroke therapy, we aimed to assess the protective effect against PSI of an orodispersible film loaded with silkworm pupae hydrolysate and a combined extract of holy basil and ginger (JP1), which show antioxidant, and anti-inflammation effects. Methods: Male Wistar rats (200-250 g) were administered JP1 at doses of 1, 10, and 100 mg/kg BW 45 min before a 6 h immobilization stress exposure for 14 days. Then, the right middle cerebral artery was permanently occluded (MCAO) and JP1 was continually administered for 21 days after MCAO. Spatial and non-spatial memory and the possible underlying mechanisms were also explored. Results: JP1 improved oxidative stress, inflammation, apoptosis, Erk signaling pathway, cholinergic function, and the growth of Lactobacillus and Bifidobacterium spp. in feces. These results suggest that JP1 improves PSCI, possibly involving the above mechanisms. Furthermore, serum corticosterone also decreased. Conclusions: Our results suggest that JP1 is a potential candidate for combating PSCI following exposure to stroke plus stress. However, a clear understanding of the precise active ingredient and the detailed mechanisms require further investigation.

Tlx Promotes Stroke-Induced Neurogenesis and Neuronal Repair in Young and Aged Mice

Stroke is one of the leading causes of chronic disability in humans. It has been proposed that the endogenous neural stem/progenitor cells generate new neurons in the damaged area. Still, the contribution of these cells is negligible because a low number of newborn mature neurons are formed. Tlx conventional knock-out mice, Tlx-CreERT2 mice, and Tlx-overexpressing (Tlx-OE) mice were specifically chosen for their unique genetic characteristics, which were crucial for the experiments. Permanent and transient middle cerebral artery occlusion was used to induce stroke in the mice. Immunostainings for doublecortin and GFP/BrdU/NeuN were performed to study neurogenesis and fate mapping. The rotarod test was performed to assess motor deficits. Here, we show that stroke-induced neurogenesis is dramatically increased with the additional expression of two copies of the nuclear receptor-coding gene tailless (Tlx, also known as Nr2e1), which has been shown to be a master regulator of subventricular zone (SVZ) neural stem cells (NSCs). We show that Tlx expression is upregulated after stroke, and stroke-induced neurogenesis is blocked when Tlx is inactivated. Tlx overexpression in NSCs leads to massive induction of neurogenesis via stroke. More newborn mature neurons are formed in Tlx-overexpressing mice, leading to improved coordination and motor function recovery. Most importantly, we also demonstrate that this process is sustained in aged mice, where stroke-induced neurogenesis is nearly undetectable in wild-type animals. This study provides the first stem cell-specific genetic evidence that endogenous NSCs can be exploited by manipulating their master regulator, Tlx, and thus suggests a novel therapeutic strategy for neuronal repair.

The ageing central nervous system in multiple sclerosis: the imaging perspective

The interaction between ageing and multiple sclerosis is complex and carries significant implications for patient care. Managing multiple sclerosis effectively requires an understanding of how ageing and multiple sclerosis impact brain structure and function. Ageing inherently induces brain changes, including reduced plasticity, diminished grey matter volume, and ischaemic lesion accumulation. When combined with multiple sclerosis pathology, these age-related alterations may worsen clinical disability. Ageing may also influence the response of multiple sclerosis patients to therapies and/or their side effects, highlighting the importance of adjusted treatment considerations. MRI is highly sensitive to age- and multiple sclerosis-related processes. Accordingly, MRI can provide insights into the relationship between ageing and multiple sclerosis, enabling a better understanding of their pathophysiological interplay and informing treatment selection. This review summarizes current knowledge on the immunopathological and MRI aspects of ageing in the CNS in the context of multiple sclerosis. Starting from immunosenescence, ageing-related pathological mechanisms and specific features like enlarged Virchow-Robin spaces, this review then explores clinical aspects, including late-onset multiple sclerosis, the influence of age on diagnostic criteria, and comorbidity effects on imaging features. The role of MRI in understanding neurodegeneration, iron dynamics and myelin changes influenced by ageing and how MRI can contribute to defining treatment effects in ageing multiple sclerosis patients, are also discussed.

Neuroprotective effects of Daphnetin on hippocampal neurons and blood-brain barrier integrity in a mouse model of cerebral ischemia

The purpose of this research was to assess the impact of different doses of Daphnetin (DAP, a natural compound derived from coumarin) on hippocampus neuronal injury, neurobehavioral function, blood-brain barrier (BBB) integrity, expression of claudin-5, brain-derived neurotrophic factor (BDNF), superoxide dismutase (SOD), and inflammatory markers in a mouse model of cerebral ischemia. Cerebral ischemia was induced in mice through 30 minutes of bilateral common carotid occlusion (BCCAO), followed by 48 hours of reperfusion. The viability of hippocampal neurons was assessed using Cresyl violet staining and BBB function was determined by measuring Evans blue (E.B) dye leakage. Spatial memory was tested using the Radial Arm Water Maze (RAWM) task. Claudin-5 and BDNF were measured by immunofluorescence, while SOD, interleukin-1 beta (IL-1β), and nuclear factor-κB (NF-κB) expression were determined through western blotting. Administering DAP significantly increased neuron survival in the hippocampus CA1, CA3, and dentate gyrus (DG) regions and improved spatial memory dose-dependently (P<0.0001). Treatment with DAP (40 mg/kg IP) significantly reduced E.B leakage and brain water content (P<0.001). Furthermore, it increased the claudin-5, BDNF, and SOD levels and diminished NF-κB and IL-1β expression (P<0.0001). The research found that DAP protected neurons in the CA1, CA3, and DG areas of the hippocampus, enhanced behavioral functions, and preserved BBB integrity in a cerebral ischemia model. This positive impact is achieved by increasing the expression of claudin-5, BDNF, and SOD and diminishing neuroinflammation. Further research is required to clarify the mechanisms and possible clinical uses.

Advancements in the mechanisms of Naotai formula in treating stroke: A multi-target strategy

Stroke represents a significant global health challenge, characterized by high incidence, mortality, disability, and recurrence rates, leading to substantial socioeconomic burdens. Despite advancements in acute management and prevention, effective post-stroke recovery strategies remain limited. Naotai Formula (NTF), a traditional Chinese medicine compound, has garnered attention for its potential in stroke treatment, encompassing both ischemic and hemorrhagic types. This review synthesizes recent advancements in basic and clinical research on NTF, focusing on its mechanisms of action in stroke therapy. The formula's multifaceted effects include promoting neuronal regeneration, combating oxidative stress, regulating lipid metabolism, and modulating iron homeostasis. Through a multi-target approach, NTF addresses the complex pathophysiology of stroke, suggesting a promising complementary strategy for stroke recovery. Despite promising findings, further research is required to elucidate its active components, potential side effects, and optimized therapeutic protocols. The integration of traditional Chinese medicine, like NTF, with conventional treatments may enhance stroke management strategies, urging the need for high-quality clinical trials and evidence-based guidelines.

Effectiveness of anthocyanin-containing foods and nutraceuticals in mitigating oxidative stress, inflammation, and cardiovascular health-related biomarkers: a systematic review of animal and human interventions

Cardiovascular diseases (CVDs) are a group of chronic health disorders prevalent worldwide that claim millions of lives yearly. Inflammation and oxidative stress are intricately associated with myocardial tissue damage, endothelial dysfunction, and increased odds of heart failure. Thus, dietary strategies aimed at decreasing the odds of CVDs are paramount. In this regard, the consumption of anthocyanins, natural pigments found in edible flowers, fruits, and vegetables, has attracted attention due to their potential to promote cardiovascular health. The main mechanisms of action linked with their protective effects on antioxidant and anti-inflammatory activities, serum lipid profile modulation, and other cardiovascular health parameters are explained and exemplified. However, little is known about the dose-dependency nature of the effects, which anthocyanin has better efficiency, and whether anthocyanin-containing foods display better in vivo efficacy than nutraceuticals (i.e., concentrated extracts containing higher levels of anthocyanins than foods). Thus, this systematic review focused on determining the effects of anthocyanin-containing foods and nutraceuticals on biomarkers associated with CVDs using animal studies and human interventions supported by in vitro mechanistic insights. Overall, the results showed that the regular consumption of anthocyanin-containing foods and nutraceuticals improved vascular function, lipid profile, and antioxidant and anti-inflammatory effects. The daily dosage, the participants' health status, and the duration of the intervention also significantly influenced the results.

A Study to Estimate the Red Cell Width Distribution and the Mean Platelet Volume in Predicting the 30-Day Mortality in Acute Ischemic Stroke Patients

Background Acute ischemic stroke, a clinical disorder caused by nontraumatic cerebrovascular disease, has an acute onset, frequently causes neurological deficit, and may persist for >24 hours or can be fatal in <24 hours. This study aimed to assess the red cell width distribution (RDW) and the mean platelet volume (MPV) in predicting 30-day mortality in acute ischemic stroke patients. In general, patients with acute ischemic stroke have a rather high mortality rate in the first 30 days due to various complications, but post the 30-day mark, the prognosis is comparatively better. Material and methods The present study was conducted on patients with a confirmed diagnosis of acute ischemic stroke based on history, physical examination, CT scan, and/or diffusion-weighted MRI scan performed during the first 24 hours. It was a prospective and cross-sectional study done at Saveetha Medical College over a period of two years. The data was collected by using the intra-hospital network and was analyzed using the IBM SPSS Statistics for Windows, Version 20 (Released 2011; IBM Corp., Armonk, New York, United States). Results In the present study, among 100 patients, the mean age was 57.4 ± 13.36 years. About 55% of our subjects were males in our study. The RDW on the 1stday was 14.17 ± 0.708, and it reduced drastically on the 30thday to1st 13.55 ± 1.11, and it was statically significant (p = 0.000). The MPV on day 1 was 11.11 ± 0.969 and, on day 30, was 10.82 ± 0.90; the MPV was reduced considerably on day 30, which was statistically significant (p = 0.000). RDW on the 1st day was significantly correlated with the MPV and the volume of stroke. The correlation was significant at the 0.01 level (two-tailed). On the 30th day of acute ischemic stroke patients, the red blood cell (RBC) width was significantly correlated with the MPV. The correlation was significant at the 0.01 level (two-tailed). At the end of 30 days, 10% mortality was observed in the present study. Day 30 saw a significant decrease in the MPV and RDW, particularly in the moderate to severe and severe categories. The National Institutes of Health Stroke Scale (NIHSS) score and the volume of stroke were significantly associated with the 30-day outcome.  Conclusion The RDW and the MPV are well correlated in predicting the 30-day mortality in acute ischemic stroke patients. This could potentially be used as a significant marker for predicting mortality in stroke patients in the future, but to increase the generalization, further studies need to be carried out at other demographically distinct medical centers.

Evolving Clinical-Translational Investigations of Cerebroprotection in Ischemic Stroke

Ischemic stroke is a highly morbid disease, with over 50% of large vessel stroke (middle cerebral artery or internal carotid artery terminus occlusion) patients suffering disability despite maximal acute reperfusion therapy with thrombolysis and thrombectomy. The discovery of the ischemic penumbra in the 1980s laid the foundation for a salvageable territory in ischemic stroke. Since then, the concept of neuroprotection has been a focus of post-stroke care to (1) minimize the conversion from penumbra to core irreversible infarct, (2) limit secondary damage from ischemia-reperfusion injury, inflammation, and excitotoxicity and (3) to encourage tissue repair. However, despite multiple studies, the preclinical-clinical research enterprise has not yet created an agent that mitigates post-stroke outcomes beyond thrombolysis and mechanical clot retrieval. These translational gaps have not deterred the scientific community as agents are under continuous investigation. The NIH has recently promoted the concept of cerebroprotection to consider the whole brain post-stroke rather than just the neurons. This review will briefly outline the translational science of past, current, and emerging breakthroughs in cerebroprotection and use of these foundational ideas to develop a novel paradigm for optimizing stroke outcomes.