Antioxidant strategies in the treatment of stroke

Stroke: Evolution of newer treatment modalities for acute ischemic stroke

Acute ischemic stroke is one of the leading causes of morbidity and mortality worldwide. Restoration of cerebral blood flow to affected ischemic areas has been the cornerstone of therapy for patients for eligible patients as early diagnosis and treatment have shown improved outcomes. However, there has been a paradigm shift in the management approach over the last decade, and with the emphasis currently directed toward including newer modalities such as neuroprotection, stem cell treatment, magnetic stimulation, anti-apoptotic drugs, delayed recanalization, and utilization of artificial intelligence for early diagnosis and suggesting algorithm-based management protocols.

Neuroprotective effects of the combined treatment of resveratrol and urapidil in experimental cerebral ischemia-reperfusion injury in rats

PURPOSE

To evaluate the neuroprotective effect of resveratrol, urapidil, and a combined administration of these drugs against middle cerebral artery occlusion (MCAO) induced ischemia/reperfusion (IR) injury model in rats.

METHODS

Thirty-five rats were divided into five groups of seven animals each. Animals in IR, IR resveratrol (IRr), IR urapidil (IRu), and IR + combination of resveratrol and urapidil (IRc) were exposed to MCAO induced cerebral ischemia reperfusion injury model. Rats in IRr and IRu groups received 30-mg/kg resveratrol and 5-mg/kg urapidil respectively. Animals in IRc received a combined treatment of both drugs. At the end of the study, brain tissues were used for oxidative stress (malondialdehyde, glutathione, and superoxide dismutase), pro-apoptotic caspase-3, anti-apoptotic Bcl-2, and pro-inflammatory tumor necrosis factor-α cytokine level measurements.

RESULTS

The MCAO model successfully replicated IR injury with significant histopathological changes, elevated tissue oxidative stress, and upregulated apoptotic and inflammatory protein expression in IR group compared to control group (p < 0.001). All parameters were significantly alleviated in IRr group compared to IR group (all p < 0.05). In IRu group, all parameters except for caspase-3 and Bcl-2 were also significantly different than IR group (all p < 0.05). The IRc group showed the biggest difference compared to IR group in all parameters (all p < 0.001). The IRc had higher superoxide dismutase and Bcl-2 levels, and lower caspase-3 levels compared to both IRr and IRu groups (all p < 0.05). Also, the IRc group had lower MDA and TNF-α levels compared to IRu group (all p < 0.05).

CONCLUSIONS

The results indicate that combined treatment of resveratrol and urapidil may be a novel strategy to downregulate neurodegeneration in cerebral IR injury.

TXNIP knockdown protects rats against bupivacaine-induced spinal neurotoxicity via the inhibition of oxidative stress and apoptosis

Bupivacaine (BUP) is an anesthetic commonly used in clinical practice that when used for spinal anesthesia, might exert neurotoxic effects. Thioredoxin-interacting protein (TXNIP) is a member of the α-arrestin protein superfamily that binds covalently to thioredoxin (TRX) to inhibit its function, leading to increased oxidative stress and activation of apoptosis. The role of TXNIP in BUP-induced oxidative stress and apoptosis remains to be elucidated. In this context, the present study aimed to explore the effects of TXNIP knockdown on BUP-induced oxidative stress and apoptosis in the spinal cord of rats and in PC12 cells through the transfection of adeno-associated virus-TXNIP short hairpin RNA (AAV-TXNIP shRNA) and siRNA-TXNIP, respectively. In vivo, a rat model of spinal neurotoxicity was established by intrathecally injecting rats with BUP. The BUP + TXNIP shRNA and the BUP + Control shRNA groups of rats were injected with an AAV carrying the TXNIP shRNA and the Control shRNA, respectively, into the subarachnoid space four weeks prior to BUP treatment. The Basso, Beattie & Bresnahan (BBB) locomotor rating score, % MPE of TFL, H&E staining, and Nissl staining analyses were conducted. In vitro, 0.8 mM BUP was determined by CCK-8 assay to establish a cytotoxicity model in PC12 cells. Transfection with siRNA-TXNIP was carried out to suppress TXNIP expression prior to exposing PC12 cells to BUP. The results revealed that BUP effectively induced neurological behavioral dysfunction and neuronal damage and death in the spinal cord of the rats. Similarly, BUP triggered cytotoxicity and apoptosis in PC12 cells. In addition, treated with BUP both in vitro and in vivo exhibited upregulated TXNIP expression and increased oxidative stress and apoptosis. Interestingly, TXNIP knockdown in the spinal cord of rats through transfection of AAV-TXNIP shRNA exerted a protective effect against BUP-induced spinal neurotoxicity by ameliorating behavioral and histological outcomes and promoting the survival of spinal cord neurons. Similarly, transfection with siRNA-TXNIP mitigated BUP-induced cytotoxicity in PC12 cells. In addition, TXNIP knockdown mitigated the upregulation of ROS, MDA, Bax, and cleaved caspase-3 and restored the downregulation of GSH, SOD, CAT, GPX4, and Bcl2 induced upon BUP exposure. These findings suggested that TXNIP knockdown protected against BUP-induced spinal neurotoxicity by suppressing oxidative stress and apoptosis. In summary, TXNIP could be a central signaling hub that positively regulates oxidative stress and apoptosis during neuronal damage, which renders TXNIP a promising target for treatment strategies against BUP-induced spinal neurotoxicity.

Therapeutic potential of berries in age-related neurological disorders

Aging significantly impacts several age-related neurological problems, such as stroke, brain tumors, oxidative stress, neurodegenerative diseases (Alzheimer's, Parkinson's, and dementia), neuroinflammation, and neurotoxicity. Current treatments for these conditions often come with side effects like hallucinations, dyskinesia, nausea, diarrhea, and gastrointestinal distress. Given the widespread availability and cultural acceptance of natural remedies, research is exploring the potential effectiveness of plants in common medicines. The ancient medical system used many botanical drugs and medicinal plants to treat a wide range of diseases, including age-related neurological problems. According to current clinical investigations, berries improve motor and cognitive functions and protect against age-related neurodegenerative diseases. Additionally, berries may influence signaling pathways critical to neurotransmission, cell survival, inflammation regulation, and neuroplasticity. The abundance of phytochemicals in berries is believed to contribute to these potentially neuroprotective effects. This review aimed to explore the potential benefits of berries as a source of natural neuroprotective agents for age-related neurological disorders.

Computational-based investigation of antioxidative potential polyphenolic compounds of Salvia officinalis L.: combined DFT and molecular docking approaches

CONTEXT

The antioxidant properties of the three polyphenolic compounds (carnosol, cirsiliol, and luteolin) of Salvia officinalis L. were investigated employing the density functional theory (DFT) calculations at the B3LYP of basis set at 6-311 +  + G (d, p) in order to evaluate their antioxidant activity. The enthalpies of reactions associated with the SET-PT, SPLET, and HAT mechanisms were analyzed in gas and in different solvents using the CPCM (conductor-like polarizable continuum) model. For all possible hydrogen donor sites, the corresponding parameters (BDE, AIP, PDE, PA, ETE, HOMOs, and LUMOs) and reactivity indices (IPE, EA, Χ, η, S, and ω) were also evaluated. The calculated results showed that derivatives 12-OH, 11-OH, 4'-OH, and 3'-OH had the lowest antioxidant activity. The results showed as well that carnosol, cirsiliol, and luteolin have higher reactivity compared to ascorbic acid and could be considered better antioxidants. According to research, the catechol group is crucial in influencing the studied compounds antioxidant activity. The theoretically predicted order of antioxidant efficiencies in this work agrees well with the QSAR (quantitative structure-activity relationship) data. The findings show that in the vacuum as well as benzene media. HAT would be the most effective mechanism; in contrast, the thermodynamic equilibrium approach in polar media is the SPLET mechanism. Likewise, the outcomes of the docking modeling confirm that the selected molecules have high inhibitory activity to glutathione-S-transferases (GSTs) receptors. Moreover, they have very important pharmacokinetic, chemical, and biological profiles. Finally, all the results show that the three natural molecules have good pharmacokinetic profiles, particularly the bioavailability and permeability toward biological membranes.

METHODS

The software packages used in this investigation are Gaussian 16, Discovery studio Visualizer, and AutoDock vina. The three compounds (carnosol, cirsiliol, and luteolin) of Salvia officinalis L. were optimized with DFT/B3LYP of basis set at 6-311 +  + G (d, p). The optimized structures were established via vibrational analysis (i.e., no imaginary frequencies in the frequency set). All enthalpies were zero-point (ZPE) corrected. Vibrational frequency calculations were performed at 298.15 K and 1 atmosphere pressure to determine the thermodynamic characteristics of the investigated reactions. The descriptors were associated with the antioxidant mechanisms for investigated molecules in vacuum and in various solvents. The molecular docking was used by AutoDock vina to estimate and evaluate the title compounds compatibility as potential antioxidant drugs utilizing appropriate receptor proteins. The solvation effect in the medium of benzene (ɛ = 2.27) and water (ɛ = 78.39) was taken into account. Furthermore, a methanol solvent (ɛ = 32.61) was also taken into consideration to compare with the empirical data.

Neuroprotective Effects of Water Extract from Brown Algae Petalonia binghamiae in an Experimental Model of Focal Cerebral Ischemia In Vitro and In Vivo

Focal cerebral ischemia (fCI) can result in brain injury and sensorimotor deficits. Brown algae are currently garnering scientific attention as potential therapeutic candidates for fCI. This study investigated the therapeutic effects of the hot water extract of Petalonia binghamiae (wPB), a brown alga, in in vitro and in vivo models of fCI. The neuroprotective efficacy of wPB was evaluated in an in vitro excitotoxicity model established using HT-22 cells challenged with glutamate. Afterward, C57/BL6 mice were administered wPB for 7 days (10 or 100 mg/kg, intragastric) and subjected to middle cerebral artery occlusion and reperfusion (MCAO/R) operation, which was used as an in vivo fCI model. wPB co-incubation significantly inhibited cell death, oxidative stress, and apoptosis, as well as stimulated the expression of heme oxygenase-1 (HO-1), an antioxidant enzyme, and the nuclear translocation of its upstream regulator, nuclear factor erythroid 2-related factor 2 (Nrf2) in HT-22 cells challenged with glutamate-induced excitotoxicity. Pretreatment with either dose of wPB significantly attenuated infarction volume, neuronal death, and sensorimotor deficits in an in vivo fCI model. Furthermore, the attenuation of oxidative stress and apoptosis in the ischemic lesion accompanied the wPB-associated protection. This study suggests that wPB can counteract fCI via an antioxidative effect, upregulating the Nrf2/HO-1 pathway.

Geraniol protects hippocampal CA1 neurons and improves functional outcomes in global model of stroke in rats

Geraniol (GE), an acyclic monoterpene, is a chief constituent of essential oils of herbs and fruits. It possesses diverse pharmacological actions like antioxidant, anti-inflammatory, anti-apoptotic, and anti-parkinson. However, its neuroprotective potential in stroke is yet to be explored at large. The present study evaluated the neuroprotective potential of GE against the global model of cerebral ischemia/reperfusion (I/R)-injury in rats. Bilateral common carotid artery (BCCA) occlusion for 30 min followed by 7 days of reperfusion caused varied biochemical/enzymatic alterations viz. increase in levels of lipid peroxidation (LPO), nitric oxide (NO), xanthine oxidase (XO), and decrease in the levels of cerebroprotectives like superoxide dismutase (SOD), catalase (CAT), total thiols, and glutathione (GSH). GE-pretreatment markedly reversed these changes and restored the levels of protective enzymatic and non-enzymatic antioxidants near to normal compared to I/R group. Besides, GE treatment showed marked improvement in anxiety-related behavior and neuronal deficits in animals subjected to I/R injury. Moreover, 2,3,5-triphenyl tetrazolium chloride (TTC)-stained rat brain coronal sections and histopathological studies revealed neuronal protection against I/R-injury, as evidenced by a reduction in infarct area (%) and an increase in hippocampal CA1 neuronal density in the GE-treated groups. The results of this study revealed that GE exhibited potential neuroprotective activity by reducing oxidative stress and infarction area, and protecting hippocampal CA1 neurons against I/R-injury in the global stroke model in rats.

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.

Neuroprotective Effects of Tryptanthrin-6-Oxime in a Rat Model of Transient Focal Cerebral Ischemia

The activation of c-Jun N-terminal kinase (JNK) plays an important role in stroke outcomes. Tryptanthrin-6-oxime (TRYP-Ox) is reported to have high affinity for JNK and anti-inflammatory activity and may be of interest as a promising neuroprotective agent. The aim of this study was to investigate the neuroprotective effects of TRYP-Ox in a rat model of transient focal cerebral ischemia (FCI), which involved intraluminal occlusion of the left middle cerebral artery (MCA) for 1 h. Animals in the experimental group were administered intraperitoneal injections of TRYP-Ox 30 min before reperfusion and 23 and 47 h after FCI. Neurological status was assessed 4, 24, and 48 h following FCI onset. Treatment with 5 and 10 mg/kg of TRYP-Ox decreased mean scores of neurological deficits by 35-49 and 46-67% at 24 and 48 h, respectively. At these doses, TRYP-Ox decreased the infarction size by 28-31% at 48 h after FCI. TRYP-Ox (10 mg/kg) reduced the content of interleukin (IL) 1β and tumor necrosis factor (TNF) in the ischemic core area of the MCA region by 33% and 38%, respectively, and attenuated cerebral edema by 11% in the left hemisphere, which was affected by infarction, and by 6% in the right, contralateral hemisphere 24 h after FCI. TRYP-Ox reduced c-Jun phosphorylation in the MCA pool at 1 h after reperfusion. TRYP-Ox was predicted to have high blood-brain barrier permeability using various calculated descriptors and binary classification trees. Indeed, reactive oxidant production was significantly lower in the brain homogenates from rats treated with TRYP-Ox versus that in control animals. Our data suggest that the neuroprotective activity of TRYP-Ox may be due to the ability of this compound to inhibit JNK and exhibit anti-inflammatory and antioxidant activity. Thus, TRYP-Ox may be considered a promising neuroprotective agent that potentially could be used for the development of new treatment strategies in cerebral ischemia.

Long non-coding RNA HOXA11-AS regulates ischemic neuronal death by targeting miR-337-3p/YBX1 signaling pathway: protective effect of dexmedetomidine

Cerebral ischemia/reperfusion (I/R) is a common neurological disease. Homeobox A11 antisense RNA (HOXA11-AS), a long non-coding RNA (lncRNA), has been demonstrated as an important regulator in diverse human cancers. However, its function and regulatory mechanism in ischemic stroke remains largely unknown. Dexmedetomidine (Dex) have received wide attraction because of its neuroprotective effects. This study aimed to explore the possible link between Dex and HOXA11-AS in protecting neuronal cells from by ischemia/reperfusion-induced apoptosis. We used oxygen-glucose deprivation and reoxygenation (OGD/R) in mouse neuroblastoma Neuro-2a cells and middle cerebral artery occlusion (MACO) mouse model to test the link. We found that Dex significantly alleviated OGD/R-induced DNA fragmentation, cell viability and apoptosis, and rescued the decreased HOXA11-AS expression after ischemic damage in Neuro-2a cells. Gain-/loss-of-function studies revealed that HOXA11-AS promoted proliferation, inhibited apoptosis in Neuro-2a cells exposed to OGD/R. Knockdown of HOXA11-AS decreased the protective effect of Dex on OGD/R cells. HOXA11-AS was found to transcriptionally regulate microRNA-337-3p (miR-337-3p) expression as evidenced by luciferase reporter assay, while miR-337-3p expression was upregulated following ischemia in vitro and in vivo. Besides, knockdown of miR-337-3p protected OGD/R-induced apoptotic death of Neuro-2a cells. Furthermore, HOXA11-AS functioned as a competing endogenous RNA (ceRNA) and competed with Y box protein 1 (Ybx1) mRNA for directly binding to miR-337-3p, which protected ischemic neuronal death. Dex treatment protected against ischemic damage and improved overall neurological functions in vivo. Our data suggest a novel mechanism of Dex neuroprotection for ischemic stroke through regulating lncRNA HOXA11-AS by targeting the miR-337-3p/Ybx1 signaling pathway, which might help develop new strategies for the therapeutic interventions in cerebral ischemic stroke.

MiR-99b regulates cerebral ischemia neuronal injury through targeting IGF1R

BACKGROUND

Recently, microRNA-99b (miR-99b) shows diverse functions in different human disease. However, further studies about the potential effect of miR-99b in cerebral ischemia injury still need to be done.

METHODS

The expressions of miR-99b and IGF1R were detected via RT-qPCR assay. Western blot assay was applied to measure the protein expression of Caspase-3, Bax and Bcl-2. MTT assay was used to observe cell viability of SH-SY5Y cells. The association of miR-99b and IGF1R was testified by dual luciferase assay. And human SH-SY5Y cells were treated with the oxygen-glucose deprivation/reperfusion (OGD/R) to mimic CIR injury.

RESULTS

The expression of miR-99b was increased in the OGD/R model. And upregulation of miR-99b promoted cell viability and inhibited apoptosis induced by OGD/R. Moreover, IGF1R was confirmed as a direct target gene of miR-99b. The expression of IGF1R was obviously decreased under OGD/R conditions.

CONCLUSIONS

MiR-99b promoted the viability and suppressed apoptosis of SH-SY5Y cells under OGD/R conditions through targeting IGF1R.

Inhibition of perilipin 2 attenuates cerebral ischemia/reperfusion injury by blocking NLRP3 inflammasome activation both in vivo and in vitro

Cerebral ischemia/reperfusion (CI/R) usually causes neuroinflammation within the central nervous system, further prompting irreversible cerebral dysfunction. Perilipin 2 (Plin2), a lipid droplet protein, has been reported to exacerbate the pathological process in different diseases, including inflammatory responses. However, the role and mechanism of Plin2 in CI/R injury are unclear. In this study, the rat models of transient middle cerebral artery occlusion followed by reperfusion (tMCAO/R) were established to mimic I/R injury, and we found that Plin2 was highly expressed in the ischemic penumbra of tMCAO/R rats. The siRNA-mediated knockdown of Plin2 significantly decreased neurological deficit scores and reduced infarct areas in rats induced by I/R. Detailed investigation showed that Plin2 deficiency alleviated inflammation of tMCAO/R rats as evidenced by reduced secretion of proinflammatory factors and the blockade of NLR family pyrin domain containing 3 (NLRP3) inflammasome activation. In vitro experiments showed that Plin2 expression was upregulated in mouse microglia subjected to oxygen-glucose deprivation/reoxygenation (OGD/R). Plin2 knockdown inhibited OGD/R-induced microglia activation and the accumulation of inflammation-related factors. Taken together, this study demonstrates that lipid droplet protein Plin2 contributes to the pathologic process of CI/R damage by impacting inflammatory response and NLRP3 inflammasome activation. Thus, Plin2 may provide a new therapeutic direction for CI/R injury.

Oxidative stress in cerebrovascular disease and associated diseases

Cellular aging is the most severe risk factor for neurodegenerative disease. Simultaneously, oxidative stress (OS) is a critical factor in the aging process, resulting from an imbalance between reactive oxygen and nitrogen species and the antioxidant defense system. Emerging evidence indicates that OS is a common cause of several age-related brain pathologies, including cerebrovascular diseases. Elevated OS disrupts endothelial functional ability by diminishing the bioavailability of nitric oxide (a vascular dilator), induces atherosclerosis, and impairs vasculature, which are all common characteristics of cerebrovascular disease. In this review, we summarize evidence supporting an active role of OS in cerebrovascular disease progression, focusing primarily on stroke pathogenesis. We briefly discuss hypertension, diabetes, heart disease, and genetic factors that are often linked to OS and are considered associated factors influencing stroke pathology. Finally, we discuss the current pharmaceutics/therapeutics available for treating several cerebrovascular diseases.

Neuroprotective efficacy of N-t-butylhydroxylamine (NtBHA) in transient focal ischemia in rats

The pharmacological or toxicological activities of the degradation products of drug candidates have been unaddressed during the drug development process. Ischemic stroke accounts for 80% of all strokes and is responsible for considerable mortality and disability worldwide. Despite decades of research on neuroprotective agents, tissue plasminogen activators (t-PA), a thrombolytic agent, remains the only approved acute stroke pharmacological therapy. NXY-059, a free radical scavenger, exhibited striking neuroprotective properties in preclinical models and met all the criteria established by the Stroke Academic Industry Roundtable (STAIR) for a neuroprotective agent. In phase 3 clinical trials, NXY-059 exhibited significant neuroprotective effects in one trial (SAINT-I), but not in the second (SAINT-II). Some have hypothesized that N-t-butyl hydroxylamine (NtBHA), a breakdown product of NXY-059 was the actual neuroprotective agent in SAINT-I and that changes to the formulation of NXY-059 to prevent its breakdown to NtBHA in SAINT -II was the reason for the lack of efficacy. We evaluated the neuroprotective effect of NtBHA in N-methyl-D-aspartate (NMDA)-treated primary neurons and in rat focal cerebral ischemia. NtBHA significantly attenuated infarct volume in rat transient focal ischemia, and attenuated NMDA-induced cytotoxicity in primary cortical neurons. NtBHA also reduced free radical generation and exhibited mitochondrial protection.

Targeting Oxidative Stress in Intracerebral Hemorrhage: Prospects of the Natural Products Approach

Intracerebral hemorrhage (ICH), the second most common subtype of stroke, remains a significant cause of morbidity and mortality worldwide. The pathological mechanism of ICH is very complex, and it has been demonstrated that oxidative stress (OS) plays an important role in the pathogenesis of ICH. Previous studies have shown that OS is a therapeutic target after ICH, and antioxidants have also achieved some benefits in the treatment of ICH. This review aimed to explore the promise of natural products therapy to target OS in ICH. We searched PubMed using the keywords “oxidative stress in intracerebral hemorrhage” and “natural products in intracerebral hemorrhage”. Numerous animal and cell studies on ICH have demonstrated the potent antioxidant properties of natural products, including polyphenols and phenolic compounds, terpenoids, alkaloids, etc. In summary, natural products such as antioxidants offer the possibility of treatment of OS after ICH. However, researchers still have a long way to go to apply these natural products for the treatment of ICH more widely in the clinic.

Free radical biology in neurological manifestations: mechanisms to therapeutics interventions

Recent advancements and growing attention about free radicals (ROS) and redox signaling enable the scientific fraternity to consider their involvement in the pathophysiology of inflammatory diseases, metabolic disorders, and neurological defects. Free radicals increase the concentration of reactive oxygen and nitrogen species in the biological system through different endogenous sources and thus increased the overall oxidative stress. An increase in oxidative stress causes cell death through different signaling mechanisms such as mitochondrial impairment, cell-cycle arrest, DNA damage response, inflammation, negative regulation of protein, and lipid peroxidation. Thus, an appropriate balance between free radicals and antioxidants becomes crucial to maintain physiological function. Since the 1brain requires high oxygen for its functioning, it is highly vulnerable to free radical generation and enhanced ROS in the brain adversely affects axonal regeneration and synaptic plasticity, which results in neuronal cell death. In addition, increased ROS in the brain alters various signaling pathways such as apoptosis, autophagy, inflammation and microglial activation, DNA damage response, and cell-cycle arrest, leading to memory and learning defects. Mounting evidence suggests the potential involvement of micro-RNAs, circular-RNAs, natural and dietary compounds, synthetic inhibitors, and heat-shock proteins as therapeutic agents to combat neurological diseases. Herein, we explain the mechanism of free radical generation and its role in mitochondrial, protein, and lipid peroxidation biology. Further, we discuss the negative role of free radicals in synaptic plasticity and axonal regeneration through the modulation of various signaling molecules and also in the involvement of free radicals in various neurological diseases and their potential therapeutic approaches. The primary cause of free radical generation is drug overdosing, industrial air pollution, toxic heavy metals, ionizing radiation, smoking, alcohol, pesticides, and ultraviolet radiation. Excessive generation of free radicals inside the cell R1Q1 increases reactive oxygen and nitrogen species, which causes oxidative damage. An increase in oxidative damage alters different cellular pathways and processes such as mitochondrial impairment, DNA damage response, cell cycle arrest, and inflammatory response, leading to pathogenesis and progression of neurodegenerative disease other neurological defects.

(±)-5-bromo-2-(5-fluoro-1-hydroxyamyl) Benzoate Protects Against Oxidative Stress Injury in PC12 Cells Exposed to H2O2 Through Activation of Nrf2 Pathway

Background: Oxidative stress is associated with the pathogenesis of ischemic stroke (±)-5-bromo-2-(5-fluoro-1-hydroxyamyl) benzoate (BFB) is a novel compound modified by dl-3-n-butylphthalide (NBP). Here, we hypothesized that BFB may protect the PC12 cells against H₂O₂-induced oxidative stress injury through activation of the Nrf2 pathway.

Methods: We measured the cell viability and levels of lactate dehydrogenase (LDH), malondialdehyde (MDA), glutathione (GSH), and reactive oxygen species (ROS) to determine the construction of the H₂O₂-induced models of oxidative stress in PC12 cells. Additionally, apoptotic cell death, mitochondrial membrane potential, and cellular morphology were examined to determine the effect of BFB on oxidative stress injury in H₂O₂-treated PC12 cells. The expression levels of Nrf2-related and autophagy-related genes and proteins were detected using real time quantative PCR (RT-qPCR), Western Blot, and immunofluorescence analyses.

Results: Our study showed that BFB treatment reduced the elevated levels of MDA, LDH, and ROS, and decreased cell viability and GSH in H₂O₂-treated PC12 cells. We also observed the elevated expression of Nrf2 pathway-related factors and intranuclear transitions and found that Nrf2 inhibitors (ML385) could block the protective effect of BFB. The inhibitory effect of BFB on oxidative stress may be partially regulated by Nrf2 activation, and the initiation and induction of autophagy.

Conclusion: BFB inhibited H₂O₂-induced oxidative stress injury in PC12 cells by activating the Nrf2 pathway, initiating and inducing autophagy, suggesting that BFB may be a promising therapeutic agent in treating neurological disorders like cerebral ischemia.

Comprehensive insight into endothelial progenitor cell-derived extracellular vesicles as a promising candidate for disease treatment

Endothelial progenitor cells (EPCs), which are a type of stem cell, have been found to have strong angiogenic and tissue repair capabilities. Extracellular vesicles (EVs) contain many effective components, such as cellular proteins, microRNAs, messenger RNAs, and long noncoding RNAs, and can be secreted by different cell types. The functions of EVs depend mainly on their parent cells. Many researchers have conducted functional studies of EPC-derived EVs (EPC-EVs) and showed that they exhibit therapeutic effects on many diseases, such as cardiovascular disease, acute kidney injury, acute lung injury, and sepsis. In this review article, we comprehensively summarized the biogenesis and functions of EPCs and EVs and the potent role of EPC-EVs in the treatment of various diseases. Furthermore, the current problems and future prospects have been discussed, and further studies are needed to compare the therapeutic effects of EVs derived from various stem cells, which will contribute to the accelerated translation of these applications in a clinical setting.

Brain Targeting, Antioxidant Polymeric Nanoparticles for Stroke Drug Delivery and Therapy

Ischemic stroke is a leading cause of death and disability and remains without effective treatment options. Improved treatment of stroke requires efficient delivery of multimodal therapy to ischemic brain tissue with high specificity. Here, this article reports the development of multifunctional polymeric nanoparticles (NPs) for both stroke treatment and drug delivery. The NPs are synthesized using an reactive oxygen species (ROS)-reactive poly (2,2'-thiodiethylene 3,3'-thiodipropionate) (PTT) polymer and engineered for brain penetration through both thrombin-triggered shrinkability and AMD3100-mediated targeted delivery. It is found that the resulting AMD3100-conjugated, shrinkable PTT NPs, or ASPTT NPs, efficiently accumulate in the ischemic brain tissue after intravenous administration and function as antioxidant agents for effective stroke treatment. This work shows ASPTT NPs are capable of efficient encapsulation and delivery of glyburide to achieve anti-edema and antioxidant combination therapy, resulting in therapeutic benefits significantly greater than those by either the NPs or glyburide alone. Due to their high efficiency in brain penetration and excellent antioxidant bioactivity, ASPTT NPs have the potential to be utilized to deliver various therapeutic agents to the brain for effective stroke treatment.

Pomelo Peel Essential Oil Ameliorates Cerebral Ischemia-Reperfusion Injury through Regulating Redox Homeostasis in Rats and SH-SY5Y Cells

Background

In cardiac accident/cardiopulmonary resuscitation (CA/CPR) rat model, oxidative stress occurs during cerebral ischemia/reperfusion injury (CIRI), and antioxidative treatment has a neuroprotective effect. The antioxidant capabilities of pomelo peel essential oil (PPEO) have mostly been investigated in vitro, with little convincing data in vivo, particularly whether PPEO has a neuroprotective role against CIRI.

Methods

In this investigation, a CA/CPR SD rat model and an oxygen-glucose deprivation/reperfusion (OGD/R) SH-SY5Y cell model were used to imitate the CIRI, and the neuroprotective role of PPEO was discovered in both. The morphological changes of neurons after PPEO treatment were observed using Nissl staining and transmission electron microscopy, while biochemical markers such as MDA, GSH, and Fe²⁺ were evaluated. Furthermore, western blot, immunofluorescence, and immunohistochemistry were used to examine the proteins GPX4, SLC7A11, ACSL4, and Nrf2.

Results

Significant morphological alterations were identified during the pathological progression of CIRI. The neurologic deficit scores improved after PPEO therapy, and the expression of GPX4 and SLC7A11 increased, while the levels of intracellular Fe²⁺, ROS, and ACSL4 declined. PPEO also prevented CIRI caused by erastin (a specific inhibitor of SLC7A11) or RSL3 (inhibitor of GPX4). Furthermore, PPEO-induced increases in SLC7A11 and GPX4 may be related to Nrf2 translocation to the nucleus.

Conclusions

In vitro and in vivo, we verified and investigated the neuroprotective effects of PPEO on CIRI. The underlying process may be connected to redox homeostasis regulation, which enhances antioxidative capacity through upmodulation of SLC7A11 and GPX4. It implies that PPEO will be considered as a source of potential adjuvant therapeutic agents for improving CIRI outcomes.

Neonatal Anesthesia and Oxidative Stress

Neonatal anesthesia, while often essential for surgeries or imaging procedures, is accompanied by significant risks to redox balance in the brain due to the relatively weak antioxidant system in children. Oxidative stress is characterized by concentrations of reactive oxygen species (ROS) that are elevated beyond what can be accommodated by the antioxidant defense system. In neonatal anesthesia, this has been proposed to be a contributing factor to some of the negative consequences (e.g., learning deficits and behavioral abnormalities) that are associated with early anesthetic exposure. In order to assess the relationship between neonatal anesthesia and oxidative stress, we first review the mechanisms of action of common anesthetic agents, the key pathways that produce the majority of ROS, and the main antioxidants. We then explore the possible immediate, short-term, and long-term pathways of neonatal-anesthesia-induced oxidative stress. We review a large body of literature describing oxidative stress to be evident during and immediately following neonatal anesthesia. Moreover, our review suggests that the short-term pathway has a temporally limited effect on oxidative stress, while the long-term pathway can manifest years later due to the altered development of neurons and neurovascular interactions.

Astaxanthin Confers a Significant Attenuation of Hippocampal Neuronal Loss Induced by Severe Ischemia-Reperfusion Injury in Gerbils by Reducing Oxidative Stress

Astaxanthin is a powerful biological antioxidant and is naturally generated in a great variety of living organisms. Some studies have demonstrated the neuroprotective effects of ATX against ischemic brain injury in experimental animals. However, it is still unknown whether astaxanthin displays neuroprotective effects against severe ischemic brain injury induced by longer (severe) transient ischemia in the forebrain. The purpose of this study was to evaluate the neuroprotective effects of astaxanthin and its antioxidant activity in the hippocampus of gerbils subjected to 15-min transient forebrain ischemia, which led to the massive loss (death) of pyramidal cells located in hippocampal cornu Ammonis 1-3 (CA1-3) subfields. Astaxanthin (100 mg/kg) was administered once daily for three days before the induction of transient ischemia. Treatment with astaxanthin significantly attenuated the ischemia-induced loss of pyramidal cells in CA1-3. In addition, treatment with astaxanthin significantly reduced ischemia-induced oxidative DNA damage and lipid peroxidation in CA1-3 pyramidal cells. Moreover, the expression of the antioxidant enzymes superoxide dismutase (SOD1 and SOD2) in CA1-3 pyramidal cells were gradually and significantly reduced after ischemia. However, in astaxanthin-treated gerbils, the expression of SOD1 and SOD2 was significantly high compared to in-vehicle-treated gerbils before and after ischemia induction. Collectively, these findings indicate that pretreatment with astaxanthin could attenuate severe ischemic brain injury induced by 15-min transient forebrain ischemia, which may be closely associated with the decrease in oxidative stress due to astaxanthin pretreatment.

Exploring multifunctional antioxidants as potential agents for management of neurological disorders

Free radical or oxidative stress may be a fundamental mechanism underlying several human neurologic diseases. Therapy using free radical scavengers (antioxidants) has the potential to prevent, delay, or ameliorate many neurologic disorders. However, the biochemistry of oxidative pathobiology is complex, and optimum antioxidant therapeutic options may vary and need to be tailored to individual diseases. In vitro and animal model studies support the potential beneficial role of various antioxidant compounds in neurological disease. Antioxidants generally play an important role in reducing or preventing the cell damage and other changes which occur in the cells like mitochondrial dysfunction, DNA mutations, and lipid peroxidation in the cell membrane. Based on their mechanism of action, antioxidants can be used to treat various neurological disorders like Huntington's disease, Alzheimer's disease, and Parkinson's disease. Vitamin E has a scavenging action for reactive oxygen species (ROS) and also prevents the lipid peroxidation. Creatine generally reduces the mitochondrial dysfunction in Parkinson's disease (PD) patients. Various metal chelators are used in PD for the prevention of accumulation of the metals. Superoxidase dismutase (SOD), lipases, and proteases act as repair enzymes in patients with AD. Accordingly, the antioxidant defense system is found to be most useful for treating various neurological disorders.

Low Serum Superoxide Dismutase Is Associated With a High Risk of Cognitive Impairment After Mild Acute Ischemic Stroke

Background

Post-stroke cognitive impairment (PSCI) is a common complication after stroke, but effective therapy is limited. Identifying potential risk factors for effective intervention is warranted. We investigated whether serum superoxide dismutase (SOD) levels were related to cognitive impairment after mild acute ischemic stroke (AIS) by using a prospective cohort design.

Methods

A total of 187 patients diagnosed with mild AIS (National Institutes of Health Stroke Scale ≤ 8) were recruited. Serum SOD, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and interleukin-6 (IL-6) levels were measured, and cognitive assessments (Mini-Mental State Examination, MMSE; Montreal Cognitive Assessment, MoCA) were performed in the early phase (within 2 weeks). These indexes and assessments were repeated at 3 months after onset. MoCA < 22 was defined as early cognitive impairment (CI-E) within 2 weeks and late cognitive impairment (CI-L) at 3 months after stroke.

Results

In a survey, 105 of 187 (56.1%) patients were identified as CI-E after mild AIS. Lower serum SOD associated with higher inflammatory biomarkers (ESR, CRP, and IL-6) and worse cognitive scores was observed in CI-E patients. In a survey, 39 of 103 (37.9%) stroke patients who completed the 3-month follow-up were identified as CI-L. Serum SOD was consistently lower in CI-L patients at baseline and 3 months and positively associated with cognitive scores. In adjusted analyses, low serum SOD at baseline was independently associated with high risks of CI-E and CI-L, with odds ratios (ORs) of 0.64 and 0.33 per standard deviation increase in serum SOD, respectively. Multiple-adjusted spline regression models showed linear associations between serum SOD and CI-E (P = 0.044 for linearity) and CI-L (P = 0.006 for linearity). Moreover, 35.2% (19/54) of CI-E patients cognitively recovered during the 3-month follow-up. In multivariable analysis, SOD was identified as a protective factor for cognitive recovery after stroke (OR 1.04, 95% CI: 1.01-1.08, P = 0.024).

Conclusion

We demonstrate that low serum SOD is associated with a high risk of cognitive impairment after mild AIS, indicating SOD may be a potential modifiable factor for PSCI.

Daldinans D‒G, new isoindolinone antioxidants isolated from the ascomycete Daldinia concentrica

Four new isoindolinone derivatives, daldinans D‒G (3‒6), together with two known compounds, daldinans A and B (1 and 2), were isolated from the stroma of the ascomycete Daldinia concentrica. Chemical structures of the isolated compounds were determined by spectroscopic methods. All of these compounds exhibited antioxidant activities with IC₅₀ values of 3.21 to 39.67 µM in the 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assay.

Cross-Talk between Amyloid, Tau Protein and Free Radicals in Post-Ischemic Brain Neurodegeneration in the Form of Alzheimer’s Disease Proteinopathy

Recent years have seen remarkable progress in research into free radicals oxidative stress, particularly in the context of post-ischemic recirculation brain injury. Oxidative stress in post-ischemic tissues violates the integrity of the genome, causing DNA damage, death of neuronal, glial and vascular cells, and impaired neurological outcome after brain ischemia. Indeed, it is now known that DNA damage and repair play a key role in post-stroke white and gray matter remodeling, and restoring the integrity of the blood-brain barrier. This review will present one of the newly characterized mechanisms that emerged with genomic and proteomic development that led to brain ischemia to a new level of post-ischemic neuropathological mechanisms, such as the presence of amyloid plaques and the development of neurofibrillary tangles, which further exacerbate oxidative stress. Finally, we hypothesize that modified amyloid and the tau protein, along with the oxidative stress generated, are new key elements in the vicious circle important in the development of post-ischemic neurodegeneration in a type of Alzheimer’s disease proteinopathy.

Hypothermic preconditioning attenuates hypobaric hypoxia induced spatial memory impairment in rats

Hypobaric Hypoxia (HH) is known to cause oxidative stress in the brain that leads to spatial memory deficit and neurodegeneration. For decades therapeutic hypothermia is used to treat global and focal ischemia in preserving brain functions that proved to be beneficial in humans and rodents. Considering these previous reports, the present study was designed to establish the therapeutic potential of hypothermia preconditioning on HH induced spatial memory, biochemical and morphological changes in adult rats. Male Sprague Dawley rats were exposed to HH (7620 m, ~ 282 mmHg) for 1, 3 and 7 days with and without hypothermic preconditioning. Spatial learning memory was assessed by Morris water maze (MWM) test along with evaluation of hippocampal pyramidal neuron damage by histological study. Oxidative stress was measured by studying the levels of nitric oxide (NO), reactive oxygen species (ROS), lipid peroxidation (LPO), oxidized and reduced glutathione (GSSG and GSH). Results of MWM test indicated prolonged path length and latency to reach the platform in HH groups that regained to normal in cold pre-treated groups. A likely neurodegeneration was evident in HH groups that lessen in the cold pre-treated groups. Hypothermic preconditioning prevented spatial memory impairment and neurodegeneration in animals subjected to HH via decreasing the NO, ROS and LPO compared to control animals. The GSH level and GSH/GSSG ratio was found to be higher in preconditioned animals as compared to respective HH exposed animals, indicative of redox scavenging and restoration of hippocampal neuronal structure as well as spatial memory. Therefore, hypothermic preconditioning improves spatial memory deficit by reducing HH induced oxidative stress and hippocampal neurodegeneration, hence can be used as a multi-target prophylactic measure to combat HH induced neurodegeneration.

New antioxidants from the culture broth of Coprinopsis echinospora

During the search for natural antioxidants from fungal metabolites, three new sesquiterpene derivatives (1-3) have been isolated from the culture broth of Coprinopsis echinospora. Their structures were determined by spectroscopic methods, mainly NMR and mass spectrometric analyses. These compounds exhibited antioxidant activity with IC₅₀ values in the range of 34.4-144.5 μM in the 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical-scavenging assay.

Oxidative Stress in the Brain: Basic Concepts and Treatment Strategies in Stroke

The production of free radicals is inevitably associated with metabolism and other enzymatic processes. Under physiological conditions, however, free radicals are effectively eliminated by numerous antioxidant mechanisms. Oxidative stress occurs due to an imbalance between the production and elimination of free radicals under pathological conditions. Oxidative stress is also associated with ageing. The brain is prone to oxidative damage because of its high metabolic activity and high vulnerability to ischemic damage. Oxidative stress, thus, plays a major role in the pathophysiology of both acute and chronic pathologies in the brain, such as stroke, traumatic brain injury or neurodegenerative diseases. The goal of this article is to summarize the basic concepts of oxidative stress and its significance in brain pathologies, as well as to discuss treatment strategies for dealing with oxidative stress in stroke.

Sex differences in recovery of motor function in a rhesus monkey model of cortical injury

BACKGROUND

Stroke disproportionately affects men and women, with women over 65 years experiencing increased severity of impairment and higher mortality rates than men. Human studies have explored risk factors that contribute to these differences, but additional research is needed to investigate how sex differences affect functional recovery and hence the severity of impairment. In the present study, we used our rhesus monkey model of cortical injury and fine motor impairment to compare sex differences in the rate and degree of motor recovery following this injury.

METHODS

Aged male and female rhesus monkeys were trained on a task of fine motor function of the hand before undergoing surgery to produce a cortical lesion limited to the hand area representation of the primary motor cortex. Post-operative testing began two weeks after the surgery and continued for 12 weeks. All trials were video recorded and latency to retrieve a reward was quantitatively measured to assess the trajectory of post-operative response latency and grasp pattern compared to pre-operative levels.

RESULTS

Postmortem analysis showed no differences in lesion volume between male and female monkeys. However, female monkeys returned to their pre-operative latency and grasp patterns significantly faster than males.

CONCLUSIONS

These findings demonstrate the need for additional studies to further investigate the role of estrogens and other sex hormones that may differentially affect recovery outcomes in the primate brain.

Neuroinflammatory Triangle Presenting Novel Pharmacological Targets for Ischemic Brain Injury

Ischemic stroke is one of the leading causes of morbidity and mortality globally. Hundreds of clinical trials have proven ineffective in bringing forth a definitive and effective treatment for ischemic stroke, except a myopic class of thrombolytic drugs. That, too, has little to do with treating long-term post-stroke disabilities. These studies proposed diverse options to treat stroke, ranging from neurotropic interpolation to venting antioxidant activity, from blocking specific receptors to obstructing functional capacity of ion channels, and more recently the utilization of neuroprotective substances. However, state of the art knowledge suggests that more pragmatic focus in finding effective therapeutic remedy for stroke might be targeting intricate intracellular signaling pathways of the 'neuroinflammatory triangle': ROS burst, inflammatory cytokines, and BBB disruption. Experimental evidence reviewed here supports the notion that allowing neuroprotective mechanisms to advance, while limiting neuroinflammatory cascades, will help confine post-stroke damage and disabilities.

A Co-Doped Fe3O4 Nanozyme Shows Enhanced Reactive Oxygen and Nitrogen Species Scavenging Activity and Ameliorates the Deleterious Effects of Ischemic Stroke

Acute ischemic stroke has become the major cause of mortality and disability worldwide. Following ischemic stroke, the reperfusion injury is mainly mediated by the burst of reactive oxygen and nitrogen species (RONS). Therefore, blocking the excessive production or removing RONS holds great promise as a potential therapeutic strategy. Herein, we developed a Co-doped Fe3O4 nanozyme that is capable of scavenging H2O2, O2•-, •NO, and ONOO- in vitro and in vivo and provides neuroprotection against ischemic stroke. In vitro experiments showed that pre-incubation with the Co-Fe3O4 nanozyme could prevent neurotoxicity and neuroinflammation induced by H2O2 or lipopolysaccharide, respectively, in HT22 cells. After intravenous administration, the Co-Fe3O4 nanozyme showed no signs of toxicity in peripheral organs of C57BL/6J mice, even after prolonged delivery for 4 weeks. In permanent photothrombotic stroke model and transient middle cerebral artery occlusion stroke model, the Co-Fe3O4 nanozyme specifically accumulated in the infarct rim at 72 h post-stroke and was endocytosed by neurons, astrocytes, microglia, and endothelial cells. Importantly, the Co-Fe3O4 nanozyme delivery reduced the infarct volume in both stroke models. The observation that the Co-Fe3O4 nanozyme was efficacious in two well-characterized ischemic stroke models provides strong evidence that it represents a powerful tool for targeting oxidative and nitrosative stress in the ischemic brain.

Dynorphin A (1-8) inhibits oxidative stress and apoptosis in MCAO rats, affording neuroprotection through NMDA receptor and κ-opioid receptor channels

The contents of Dynorphin A(1-8) decreased gradually in ischemic cortices in rats and an intracerebroventricular administration of synthetic Dynorphin A(1-8) reduced the volume of cerebral infarction in our previous research. However, the specific protective mechanism is unclear and Dynorphin A(1-8) is unlikely to cross the blood-brain barrier (BBB) by noninvasive oral or intravenous administration as a macromolecule neuropeptide. In this study, intranasal administration was used to middle cerebral artery occlusion(MCAO) rats to assessed the therapeutic effects of Dynorphin A(1-8) by evaluating behavior, volume of cerebral infarct, cerebral edema ratio, histological observation. Then apoptosis neuron rate was detected by TUNEL staining. Immunohistochemical staining was carried out to explore the alteration of Bcl-2, Bax and Caspase-3. Finally, κ-opioid receptor antagonist and N-methyl-d-aspartate(NMDA) receptor antagonist were used to explore its possible mechanism. We found that MCAO rats under intranasal administration of Dynorphin A(1-8) showed better behavioral improvement, higher extent of Bcl-2, activity of SOD along with much lower level of infarction volume, brain water content, number of cell apoptosis, extent of Bax and Caspase-3, and concentration of MDA compared with those in MCAO model group and intravenous Dynorphin A(1-8) group. Administration of nor-BNI or MK-801 reversed these neuroprotective effects of intranasal Dynorphin A(1-8). In summary, Dynorphin A(1-8), with advantages of intranasal administration, could be effectively delivered to central nervous system(CNS). Dynorphin A(1-8) inhibited oxidative stress and apoptosis against cerebral ischemia/reperfusion injury, affording neuroprotection through NMDA receptor and κ-opioid receptor channels.

Licochalcone B attenuates neuronal injury through anti-oxidant effect and enhancement of Nrf2 pathway in MCAO rat model of stroke

BACKGROUND

Investigating anti-oxidant therapies that lead to the diminution of oxidative injury is priority in clinical. We herein aimed to explore whether and how Licochalcone B (Lico B) act as an anti-oxidant in the stroke model.

METHODS

Middle cerebral artery occlusion (MCAO) was constructed as stroke model and exposed to various doses of Lico B. Behavioral tests and neurological behavior status were detected for neurological function examination. Histological staining was used for evaluating cerebral injury, and neuronal apoptosis or damage. Levels of oxidative stress and inflammation were also assessed by biochemical analysis and expression analysis. Nrf2 knockdown induced by lentiviral vector was used for the research on mechanism.

RESULTS

Lico B had improvement effects on cerebral infarction size, memory impairments, and neurological deficits after MCAO. Histological evaluation also revealed the amelioration of neuronal injury and apoptosis by Lico B, along with down-regulation of apoptosis-related proteins. Additionally, Lico B rescued the down-regulation of BDNF and NGF after MCAO. Moreover, Lico B suppressed the oxidative stress and inflammation, manifesting as the enhancement of SOD, GSH and IL-4, but the decline of MDA, iNOS, and TNF-α. Finally, Nrf2 knockdown reversed the Lico B-caused improvement in neuronal injury, apoptosis and oxidative stress levels.

CONCLUSIONS

The present study revealed the neuroprotective effects of Lico B in MCAO rats. Importantly, we proposed a potential mechanism that Lico B activated the Nrf2 pathway, thereby acting as anti-oxidant to attenuate neuronal injury and apoptosis after stroke. The proposed mechanism provided an encouraging possibility for anti-oxidant therapy of stroke.

Visualizing Oxidative Stress Level for Timely Assessment of Ischemic Stroke via a Ratiometric Near-Infrared-II Luminescent Nanoprobe

Ischemic stroke (IS) characterized with high morbidity and mortality rates is considered as one of the most dangerous brain diseases. The timely assessment of IS is crucial for making a clinical decision due to the severity of IS featured with time-dependence. Herein, we develop a highly reactive oxygen species (HROS)-responsive ratiometric near-infrared-II (NIR-II) nanoprobe based on a dye-sensitized system between IR-783 dye and lanthanide-doped nanoparticles. Once intravenously injected into the mice, the probe is rapidly accumulated at a lesion site by recognizing the activated endothelial cell or impaired blood-brain barrier (BBB) in the ischemic area and further responds to HROS, thereby allowing in vivo imaging of the oxidative stress level. The probe is not only able to discriminate the salvageable ischemic tissue from infarcted stroke core by visualizing the enriched degree of the probe at the lesion site but also can grade the salvageable ischemic tissue by analyzing the oxidative stress level. In addition, the ischemia area was clearly delineated by NIR-II luminescence imaging after cerebral ischemia for 30 min, which is significantly earlier than with the magnetic resonance imaging (MRI) method, thereby providing a practical tool for the timely assessing of IS.

Reactive oxygen species (ROS): utilizing injectable antioxidative hydrogels and ROS-producing therapies to manage the double-edged sword

Reactive oxygen species (ROS) are generated in cellular metabolism and are essential for cellular signalling networks and physiological functions. However, the functions of ROS are 'double-edged swords' to living systems that have a fragile redox balance between ROS generation and elimination. A modest increase of ROS leads to enhanced cell proliferation, survival and benign immune responses, whereas ROS stress that overwhelms the cellular antioxidant capacity can damage nucleic acids, proteins and lipids, resulting in oncogenic mutations and cell death. ROS are therefore involved in many pathological conditions. On the other hand, ROS present selective toxicity and have been utilised against cancer and pathogens, thus also acting as a double-edged sword in the healthcare field. Injectable antioxidative hydrogels are gel precursors that form hydrogel constructs in situ upon delivery in vivo to maintain an antioxidative capacity. These hydrogels have been developed to counter ROS-induced pathological conditions, with significant advantages of biocompatibility, excellent moldability, and minimally invasive delivery. The intrinsic, readily controllable ROS-scavenging ability of the functionalised hydrogels overcomes many drawbacks of small molecule antioxidants. This review summarises the roles of ROS under pathological conditions and describes the state-of-the-art of injectable antioxidative hydrogels. A particular emphasis is also given to current ROS-producing therapeutic interventions, enabling potential application of injectable antioxidant hydrogels to prevent the adverse effects of many cancer and infection treatments.

Differences between antioxidant defense parameters and specific trace element concentrations in healthy, benign, and malignant brain tissues

There are only a few reports examining the impact of oxidative stress in patients with benign and malignant brain tumors. In this study we investigated whether there are changes in antioxidant system (AOS) parameters and key trace elements between control, benign and malignant brain tissues. The study also aimed to examine correlations between the analyzed parameters. The study enrolled both types of brain tumors, benign tumors (BT) and malignant tumors (MT). The results were compared with control tissue (CT) without tumor infiltration collected from patients with BT. The following antioxidant parameters were determined: activities of total, manganese-containing, and copper/zinc-containing superoxide dismutase (TotSOD, MnSOD and CuZnSOD), activities of catalase, glutathione peroxidase, glutathione S-transferase, glutathione reductase and acetylcholine esterase (AChE), the concentrations of glutathione and sulfhydryl groups and of manganese (Mn), copper (Cu), zinc (Zn), and selenium (Se). BT and MT had altered activities/levels of multiple AOS parameters as compared to CT, indicating that tumor cells had an altered cell metabolism and changes in AOS represent adaptive response to increased oxidative stress. Low MnSOD and AChE and high GST activities were significant for distinguishing between MT and CT. Malignant tissue was also characterized by lower Mn and Cu concentrations relative to CT and BT. Principal Component Analysis clearly discriminated BT from CT and MT (PC1, 66.97%), while PC2 clearly discriminated CT from BT and MT (33.03%). Most correlative relationships were associated with Se in the BT group and Cu in the MT group. The results of this study reveal differences between the AOS parameters and the essential trace elements between the analyzed groups. The observed dysregulations show that oxidative stress could have an important role in disrupting brain homeostasis and its presence in the pathogenesis of benign and malignant brain tumors.

Antioxidant Activity and Toxicity Study of Cerium Oxide Nanoparticles Stabilized with Innovative Functional Copolymers

Oxidative stress, which is one of the main harmful mechanisms of pathologies including ischemic stroke, contributes to both neurons and endothelial cell damages, leading to vascular lesions. Although many antioxidants are tested in preclinical studies, no treatment is currently available for stroke patients. Since cerium oxide nanoparticles (CNPs) exhibit remarkable antioxidant capacities, the objective is to develop an innovative coating to enhance CNPs biocompatibility without disrupting their antioxidant capacities or enhance their toxicity. This study reports the synthesis and characterization of functional polymers and their impact on the enzyme-like catalytic activity of CNPs. To study the toxicity and the antioxidant properties of CNPs for stroke and particularly endothelial damages, in vitro studies are conducted on a cerebral endothelial cell line (bEnd.3). Despite their internalization in bEnd.3 cells, coated CNPs are devoid of cytotoxicity. Microscopy studies report an intracellular localization of CNPs, more precisely in endosomes. All CNPs reduces glutamate-induced intracellular production of reactive oxygen species (ROS) in endothelial cells but one CNP significantly reduces both the production of mitochondrial superoxide anion and DNA oxidation. In vivo studies report a lack of toxicity in mice. This study therefore describes and identifies biocompatible CNPs with interesting antioxidant properties for ischemic stroke and related pathologies.

Mass spectrometry-based serum lipidomics strategy to explore the mechanism of Eleutherococcus senticosus (Rupr. & Maxim.) Maxim. leaves in the treatment of ischemic stroke

Eleutherococcus senticosus (Rupr. & Maxim.) Maxim. leaves (ESL) were reported to have neuroprotective function and are also used to treat cranial and cerebral traumas as a traditional Chinese medicine and food herbage plant. However, there has been no previous study on ESL treatment for stroke at the level of lipid disorders. To clarify the mechanism of ESL in treating ischemic stroke, this study was carried out from 3 aspects, namely, the regulation of lipid disorders, protection of the nervous system, as well as anti-inflammatory and antioxidant actions. This study established a lipidomics research strategy that was developed by UPLC-Q-TOF/MS analysis. The quantification of neurotransmitters in the serum and brain tissue of rats was performed using UPLC-TQ/MS. Also, we quantified the oxidative stress and inflammatory reaction by measuring the contents of SOD, MDA, TNF-α, IL-6, and IL-10 via the ELISA kits for serum and brain tissue. According to UPLC-Q-TOF/MS-based lipidomics analysis, 27 lipidomics biomarkers were identified in this study, including PC, PE, SM, and TG, which were distributed in various lipid metabolic pathways, including glycerophospholipid, linoleic acid, alpha-linolenic acid, glycerolipid, sphingolipid, and arachidonic acid metabolism pathways. By reversing the changes in the lipid content caused by the disease, ESL has a therapeutic effect on ischemic stroke. Furthermore, quantitative results of neurotransmitters indicated that they can be regulated by ESL. Finally, the results of ELISA showed that ESL can treat ischemic stroke to a certain extent by reducing the oxidative and inflammatory damage. Therefore, ESL may play a therapeutic role in the treatment of ischemic stroke in different ways. This research preliminarily revealed the mechanism of ESL in the treatment of ischemic stroke and provided support for the further application of ESL.

Tyrosol as a Neuroprotector: Strong Effects of a "Weak" Antioxidant

The use of neuroprotective agents for stroke is pathogenetically justified, but the translation of the results of preclinical studies of neuroprotectors into clinical practice has been a noticeable failure. One of the leading reasons for these failures is the one-target mechanism of their activity. p-Tyrosol (Tyr), a biophenol, is present in a variety of natural sources, mainly in foods, such as olive oil and wine. Tyr has a wide spectrum of biological activity: antioxidant, stress-protective, anti-inflammatory, anticancer, cardioprotective, neuroprotective and many others. This review analyzes data on the neuroprotective, antioxidant, anti-inflammatory, anti-apoptotic and other kinds of Tyr activity as well as data on the pharmacokinetics of the substance. The data presented in the review substantiate the acceptability of tyr as the basis for the development of a new neuroprotective drug with multitarget activity for the treatment of ischemic stroke. Tyr is a promising molecule for the development of an effective neuroprotective agent for use in ischemic stroke.

Hyperbaric Oxygen Preconditioning Protects Against Cerebral Ischemia/Reperfusion Injury by Inhibiting Mitochondrial Apoptosis and Energy Metabolism Disturbance

Hyperbaric oxygen (HBO) therapy is considered a safe and feasible method that to provide neuroprotection against ischemic stroke. However, the therapy mechanisms of HBO have not been fully elucidated. We hypothesized that the mechanism underlying the protective effect of HBO preconditioning (HBO-PC) against cerebral ischemia/reperfusion injury was related to inhibition of mitochondrial apoptosis and energy metabolism disorder. To test this hypothesis, an ischemic stroke model was established by middle cerebral artery occlusion (MCAO) in rats. HBO-PC involved five consecutive days of pretreatment before MCAO. In additional experiments, X chromosome-linked inhibitor of apoptosis protein (XIAP) and second mitochondria-derived activator of caspases (SMAC) shRNA and NC plasmids were intraventricularly injected into rat brains after MCAO (2 h). After 24 h, all rats underwent motor function evaluation, which was assessed by modified Garcia scores. TTC staining for the cerebral infarct and cerebral edema, and TUNEL staining for cell apoptosis, were also analyzed. Reactive oxygen species and antioxidative enzymes in rat brains were detected, as well as mitochondrial complex enzyme activities, ATP levels, and Na+/K+ ATPase activity. Western blot was used to detect apoptotic proteins including Bcl-2, Bax, caspase-3, caspase-9, cyc-c, XIAP, and SMAC. HBO-PC remarkably reduced the infarct volume and improved neurological deficits. Furthermore, HBO-PC alleviated oxidative stress and regulated the expression of apoptosis-related proteins. Moreover, HBO-PC inhibited the decrease in ATP levels, mitochondrial complex enzyme activities, and Na+/K+ ATPase activity to maintain stable energy metabolism. XIAP knockdown weakened the protective effect of HBO, whereas SMAC knockdown strengthened its protective effect. The effects of HBO-PC can be attributed to inhibition of ischemia/hypoxia-induced mitochondrial apoptosis and energy metabolism disturbance. The action of HBO-PC is related to the XIAP and SMAC signaling pathways.

Impact of hydroxytyrosol on stroke: tracking therapy response on neuroinflammation and cerebrovascular parameters using PET-MR imaging and on functional outcomes

Immune cells have been implicated in influencing stroke outcomes depending on their temporal dynamics, number, and spatial distribution after ischemia. Depending on their activation status, immune cells can have detrimental and beneficial properties on tissue outcome after stroke, highlighting the need to modulate inflammation towards beneficial and restorative immune responses. Novel dietary therapies may promote modulation of pro- and anti-inflammatory immune cell functions. Among the dietary interventions inspired by the Mediterranean diet, hydroxytyrosol (HT), the main phenolic component of the extra virgin olive oil (EVOO), has been suggested to have antioxidant and anti-inflammatory properties in vitro. However, immunomodulatory effects of HT have not yet been studied in vivo after stroke. The aim of this project is therefore to monitor the therapeutic effect of a HT-enriched diet in an experimental stroke model using non-invasive in vivo multimodal imaging, behavioural phenotyping and cross-correlation with ex vivo parameters. Methods: A total of N = 22 male C57BL/6 mice were fed with either a standard chow (n = 11) or a HT enriched diet (n = 11) for 35 days, following a 30 min transient middle cerebral artery occlusion (tMCAo). T₂-weighted (lesion) and perfusion (cerebral blood flow)-/diffusion (cellular density)-weighted MR images were acquired at days 1, 3, 7, 14, 21 and 30 post ischemia. [¹⁸F]DPA-714 (TSPO, neuroinflammation marker) PET-CT scans were acquired at days 7, 14, 21 and 30 post ischemia. Infarct volume (mm³), cerebral blood flow (mL/100g/min), apparent diffusion coefficient (10^-4·mm²/s) and percentage of injected tracer dose (%ID/mL) were assessed. Behavioural tests (grip test, rotarod, open field, pole test) were performed prior and after ischemia to access therapy effects on sensorimotor functions. Ex vivo analyses (IHC, IF, WB) were performed to quantify TSPO expression, immune cells including microglia/macrophages (Iba-1, F4/80), astrocytes (GFAP) and peripheral markers in serum such as thiobarbituric acid reactive substances (TBARS) and nitric oxide (NO) 35 days post ischemia. Additionally, gene expression of pro- and anti-inflammatory markers were assessed by rt-qPCR, including tspo, cd163, arg1, tnf and Il-1β. Results: No treatment effect was observed on temporal [¹⁸F]DPA-714 uptake within the ischemic and contralateral region (two-way RM ANOVA, p = 0.71). Quantification of the percentage of TSPO⁺ area by immunoreactivity indicated a slight 2-fold increase in TSPO expression within the infarct region in HT-fed mice at day 35 post ischemia (p = 0.011) correlating with a 2-3 fold increase in Iba-1⁺ cell population expressing CD163 as anti-inflammatory marker (R² = 0.80). Most of the GFAP⁺ cells were TSPO^-. Only few F4/80⁺ cells were observed at day 35 post ischemia in both groups. No significant treatment effect was observed on global ADC and CBF within the infarct and the contralateral region over time. Behavioural tests indicated improved strength of the forepaws at day 14 post ischemia (p = 0.031). Conclusion: An HT-enriched diet significantly increased the number of Iba-1⁺ microglia/macrophages in the post-ischemic area, inducing higher expression of anti-inflammatory markers while no clear-cut effect was observed. Also, HT did not affect recovery of the cerebrovascular parameters, including ADC and CBF. Altogether, our data indicated that a prolonged dietary intervention with HT, as a single component of the Mediterranean diet, induces molecular changes that may improve stroke outcomes. Therefore, we support the use of the Mediterranean diet as a multicomponent therapy approach after stroke.

The use of hydrogel-delivered extracellular vesicles in recovery of motor function in stroke: a testable experimental hypothesis for clinical translation including behavioral and neuroimaging assessment approaches

Neural tissue engineering, nanotechnology and neuroregeneration are diverse biomedical disciplines that have been working together in recent decades to solve the complex problems linked to central nervous system (CNS) repair. It is known that the CNS demonstrates a very limited regenerative capacity because of a microenvironment that impedes effective regenerative processes, making development of CNS therapeutics challenging. Given the high prevalence of CNS conditions such as stroke that damage the brain and place a severe burden on afflicted individuals and on society, it is of utmost significance to explore the optimum methodologies for finding treatments that could be applied to humans for restoration of function to pre-injury levels. Extracellular vesicles (EVs), also known as exosomes, when derived from mesenchymal stem cells, are one of the most promising approaches that have been attempted thus far, as EVs deliver factors that stimulate recovery by acting at the nanoscale level on intercellular communication while avoiding the risks linked to stem cell transplantation. At the same time, advances in tissue engineering and regenerative medicine have offered the potential of using hydrogels as bio-scaffolds in order to provide the stroma required for neural repair to occur, as well as the release of biomolecules facilitating or inducing the reparative processes. This review introduces a novel experimental hypothesis regarding the benefits that could be offered if EVs were to be combined with biocompatible injectable hydrogels. The rationale behind this hypothesis is presented, analyzing how a hydrogel might prolong the retention of EVs and maximize the localized benefit to the brain. This sustained delivery of EVs would be coupled with essential guidance cues and structural support from the hydrogel until neural tissue remodeling and regeneration occur. Finally, the importance of including non-human primate models in the clinical translation pipeline, as well as the added benefit of multi-modal neuroimaging analysis to establish non-invasive, in vivo, quantifiable imaging-based biomarkers for CNS repair are discussed, aiming for more effective and safe clinical translation of such regenerative therapies to humans.

Saikosaponin A attenuates neural injury caused by ischemia/reperfusion

Background

Inflammation is involved in cerebral ischemia/reperfusion (I/R)-induced neurological damage. Saikosaponin A (SSa), extracted from Radix bupleuri, has been reported to exert anti-inflammatory effects. This article aimed to investigate whether SSa could ameliorate neuroinflammation mediated by ischemic stroke and the underlying mechanism.

Methods

Rat middle cerebral artery occlusion (MCAO) model was employed in this study, and the cognitive and motor functions were detected by behavioral tests. Inflammatory cytokines in the serum were detected by ELISA kits. The expression levels of Toll-like receptor 4 (TLR4), nuclear factor-kappa B (NF-κB), and high-mobility group box 1 (HMGB1) in the brain tissues were assayed with Western blot.

Results

Our results showed that SSa pretreatment could significantly reduce brain damage, improve neurological function recovery, and decrease the water content of brain tissues when compared with the model group. SSa pretreatment significantly reduced the serum HMGB1 level and downregulated the contents of inflammatory cytokines including tumor necrosis factor-α, interleukin-1 beta, and interleukin-6. Furthermore, SSa pretreatment could attenuate the decreased TLR4 and nucleus NF-κB in the brain of MCAO rats. The protein level of HMGB1 in the nucleus was significantly upregulated in the SSa pretreatment group.

Conclusion

Our results suggested that the pretreatment with SSa provided significant protection against cerebral I/R injury in rats via its anti-inflammation property by inhibiting the nucleus HMGB1 release.

The Chemical Basis of Intracerebral Hemorrhage and Cell Toxicity With Contributions From Eryptosis and Ferroptosis

Intracerebral hemorrhage (ICH) is a particularly devastating event both because of the direct injury from space-occupying blood to the sequelae of the brain exposed to free blood components from which it is normally protected. Not surprisingly, the usual metabolic and energy pathways are overwhelmed in this situation. In this review article, we detail the complexity of red blood cell degradation, the contribution of eryptosis leading to hemoglobin breakdown into its constituents, the participants in that process, and the points at which injury can be propagated such as elaboration of toxic radicals through the metabolism of the breakdown products. Two prominent products of this breakdown sequence, hemin, and iron, induce a variety of pathologies including free radical damage and DNA breakage, which appear to include events independent from typical oxidative DNA injury. As a result of this confluence of damaging elements, multiple pathways of injury, cell death, and survival are likely engaged including ferroptosis (which may be the same as oxytosis but viewed from a different perspective) and senescence, suggesting that targeting any single cause will likely not be a sufficient strategy to maximally improve outcome. Combination therapies in addition to safe methods to reduce blood burden should be pursued.

N-Adamantyl-4-methylthiazol-2-amine suppresses glutamate-induced autophagic cell death via PI3K/Akt/mTOR signaling pathways in cortical neurons

We recently reported that N-adamantyl-4-methylthiazol-2-amine (KHG26693) attenuates glutamate-induced oxidative stress and inflammation in the brain. In this study, we investigated KHG 26693 as a therapeutic agent against glutamate-induced autophagic death of cortical neurons. Treatment with KHG26693 alone did not affect the viability of cultured cortical neurons but was protective against glutamate-induced cytotoxicity in a concentration-dependent manner. KHG26693 attenuated the glutamate-induced increase in protein levels of LC3, beclin-1, and p62. Whereas glutamate decreased the phosphorylation of PI3K, Akt, and mTOR, these levels were restored by treatment with KHG26693. These results suggest that KHG26693 inhibits glutamate-induced autophagy by regulating PI3K/Akt/mTOR signaling. Finally, KHG26693 treatment also attenuated glutamate-induced increases in reactive oxygen species, glutathione, glutathione peroxidase, and superoxide dismutase levels in cortical neurons, indicating that KHG26693 also protects cortical neurons against glutamate-induced autophagy by regulating the reactive oxygen species scavenging system.