Novel Multi-Antioxidant Approach for Ischemic Stroke Therapy Targeting the Role of Oxidative Stress

HR-MS Analysis of the Covalent Binding of Edaravone to 5-Formylpyrimidine Bases and a DNA Oligonucleotide Containing a 5-Formylcytidine Residue

RATIONALE

Edaravone (EDA) is a radical scavenger and an antioxidant drug approved to treat amyotrophic lateral sclerosis and used as a research tool to explore treatment of neurodegenerative diseases and cancers. It is also a reactive agent, known as PMP (1-phenyl-3-methyl-5-pyrazolone), used for the analysis of polysaccharides composition. EDA can react with sugars and aromatic aldehydes. In this context, we have investigated the reactivity of EDA toward the biologically relevant formylated nucleobases, nucleosides, and an oligonucleotide containing a formylated residue.

METHODS

The formation of both mono- and bis-adducts between EDA and the formylated nucleobases (5-formyluracil (5fU) and 5-formylcytosine (5fC)) or the corresponding nucleosides 5-fdU and 5-fdC was characterized using high-resolution mass spectrometry (HR-MS). Similarly, the covalent binding of EDA to an 8-mer palindromic oligonucleotide d (TATG[*C]ATA) containing a single 5-fdC residue [*C] under physiological conditions was investigated using mass spectrometry.

RESULTS

For the first time, EDA is shown to react with formylated pyrimidines. Covalent and stable adducts were identified. EDA was found to react efficiently with the formylated oligonucleotide to generate mono- and bis-adducts. The rate of formation of the mono-adduct was five times higher than that of the bis-adduct. The reaction of EDA with aldehydic DNA modifications such as 5fU/5fC may have important consequences in terms of gene expression.

CONCLUSIONS

These observations raise implications for an epigenetic contribution to the mechanism of action of EDA. The biological implications of our in vitro results are discussed, notably in the frame of neurodegenerative diseases and cancers.

Amygdalin's neuroprotective effects on acute ischemic stroke in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Amygdalin, a key component of Peach kernel (semen persicae), also known as Taoren, is a traditional Chinese herb known for promoting blood circulation and alleviating blood stasis, especially in stroke treatment. This study aimed to explore the effects of amygdalin on neurological function in a rat model of acute ischemic stroke.

METHODS

We induced acute ischemic stroke in Sprague-Dawley rats by occluding the right middle cerebral artery (MCAO) for 30 min, followed by reperfusion. Amygdalin was administered intraperitoneally at doses of 5 mg, 10 mg, and 20 mg per kilogram starting 24 h post-reperfusion for three consecutive days. We assessed cerebral infarct volume and neurological function, and analyzed the brain tissue using western blotting.

RESULTS

Amygdalin significantly reduced cerebral infarct volume resulting from MCAO in the 5-mg group (amygdalin 5 mg/kg; 18.02 ± 7.51 %), 10-mg group (amygdalin 10 mg/kg; 16.25 % ± 6.35 %) and 20-mg group (amygdalin 20 mg/kg; 12.26 ± 6.69 %) compared to the sham group (phosphate buffer saline; 28.99 ± 6.36 %) (all p < 0.001). The 10-mg and 20-mg groups showed significantly lower modified neurological severity scores (mNSS) than the sham group 5 days post-reperfusion (p < 0.05, p < 0.0001, respectively). Performance on the rotarod test also improved significantly in the 10-mg group (p < 0.05) and 20-mg group (p < 0.0001) compared to the sham group, and the distance traveled in the open-field test increased significantly in the 5-mg group (p < 0.001), 10-mg group (p < 0.0001) and 20-mg group (p < 0.0001) compared to the sham group. Western blotting revealed that the expression of uncleaved caspase-3 in the cerebral cortex was greater in the sham group compared to the control (without MCAO and treatment) and the 20-mg groups (both p < 0.05), while the expression of caspase-9 was greater in the control and 20-mg groups than in the sham group (both p < 0.05).

CONCLUSION

Intraperitoneal administration of amygdalin for three days reduced cerebral infarct volume and improved neurological function in a rat model of acute ischemic stroke. Additionally, amygdalin decreased uncleaved caspase-3 expression and increased caspase-9 expression. The findings suggest that amygdalin plays a neuroprotective role through modulation of apoptosis process via the intrinsic pathway.

Remote Organ Damage Induced by Stroke: Molecular Mechanisms and Comprehensive Interventions

Significance: Damage after stroke is not only limited to the brain but also often occurs in remote organs, including the heart, lung, liver, kidney, digestive tract, and spleen, which are frequently affected by complex pathophysiological changes. The organs in the human body are closely connected, and signals transmitted through various molecular substances could regulate the pathophysiological changes of remote organs. Recent Advances: The latest studies have shown that inflammatory response plays an important role in remote organ damage after stroke, and can aggravate remote organ damage by activating oxidative stress, sympathetic axis, and hypothalamic axis, and disturbing immunological homeostasis. Remote organ damage can also cause damage to the brain, aggravating inflammatory response and oxidative damage. Critical Issues: Therefore, an in-depth exploration of inflammatory and oxidative mechanisms and adopting corresponding comprehensive intervention strategies have become necessary to reduce damage to remote organs and promote brain protection. Future Directions: The comprehensive intervention strategy involves multifaceted treatment methods such as inflammation regulation, antioxidants, and neural stem cell differentiation. It provides a promising treatment alternative for the comprehensive recovery of stroke patients and an inspiration for future research and treatment. The various organs of the human body are interconnected at the molecular level. Only through comprehensive intervention at the molecular and organ levels can we save remote organ damage and protect the brain after stroke to the greatest extent. Antioxid. Redox Signal. 00, 000-000.

Acute Administration of Edaravone Improves Cognitive Impairment in a Mouse Model of mPFC Ischemia: Crosstalk Between Necroptosis, Neuroinflammation, and Antioxidant Defense

Edaravone (Eda), a well-known free radical scavenger, has been reported as a possible therapeutic agent for ischemic stroke patients' recovery. This study aimed to investigate the effects of time-dependent treatment with Eda on medial prefrontal cortex (mPFC) ischemia. Mice were randomly allocated into six groups: control, sham, normal saline, Eda-I, Eda-II, and Eda-III. After induction of a photothrombotic ischemia in the mPFC region, Eda-I, Eda-II, and Eda-III groups received 3 mg/kg Eda intraperitoneally at the times of 0, 2, and 6 h post-surgery. After 1 day of recovery, the mice underwent behavioral tests (open field, novel object recognition, and T-maze). Next, necroptosis, NOD-like receptor protein 3 (NLRP3), and nuclear factor erythroid 2-related factor 2 (Nrf2) pathway-related protein levels were measured in the lesioned area using western blot analysis. For double confirmation, IL-1β and IL-18 were also assessed by immunofluorescence in the area. Further, histological evaluations were performed to measure tissue damage. The results showed that mPFC ischemia impaired recognition and spatial working memory without affecting locomotor activity, while immediate Eda administration improved cognitive impairments. Furthermore, acute Eda treatment reduced RIP1, RIP3, and MLKL levels, inhibited NLRP3 inflammasome proteins (NLRP3, ASC, and Cas1), decreased IL-1β and IL-18, upregulated Nrf2 and its targets (NQO-1 and HO-1), and diminished tissue damage. Our results highlighted the effects of acute administration of Eda post-stroke on improving cognitive impairments by suppressing necroptosis and NLRP3 inflammasome pathways and activating the Nrf2 antioxidant defense mechanism.

A Review on Current Aspects of Curcumin-Based Effects in Relation to Neurodegenerative, Neuroinflammatory and Cerebrovascular Diseases

Curcumin is among the most well-studied natural substances, known for its biological actions within the central nervous system, its antioxidant and anti-inflammatory properties, and human health benefits. However, challenges persist in effectively utilising curcumin, addressing its metabolism and passage through the blood-brain barrier (BBB) in therapies targeting cerebrovascular diseases. Current challenges in curcumin's applications revolve around its effects within neoplastic tissues alongside the development of intelligent formulations to enhance its bioavailability. Formulations have been discovered including curcumin's complexes with brain-derived phospholipids and proteins, or its liposomal encapsulation. These novel strategies aim to improve curcumin's bioavailability and stability, and its capability to cross the BBB, thereby potentially enhancing its efficacy in treating cerebrovascular diseases. In summary, this review provides a comprehensive overview of molecular pathways involved in interactions of curcumin and its metabolites, and brain vascular homeostasis. This review explores cellular and molecular current aspects, of curcumin-based effects with an emphasis on curcumin's metabolism and its impact on pathological conditions, such as neurodegenerative diseases, schizophrenia, and cerebral angiopathy. It also highlights the limitations posed by curcumin's poor bioavailability and discusses ongoing efforts to surpass these impediments to harness the full therapeutic potential of curcumin in neurological disorders.

The Therapeutic Effects of SP-8356, a Verbenone Derivative, with Multimodal Cytoprotective Mechanisms in an Ischemic Stroke Rat Model

An ischemic cerebral stroke results from the interruption of blood flow to the brain, triggering rapid and complex cascades of excitotoxicity, oxidative stress, and inflammation. Current reperfusion therapies, including intravenous thrombolysis and mechanical thrombectomy, cause further brain injury due to reperfusion-induced cytotoxicity. To date, novel cytoprotective therapies that could address these challenges have yet to be developed, likely due to the limitations of targeting a single pathologic mechanism. To address these unmet clinical needs, we investigated a synthetic verbenone derivative, SP-8356, as a potential multi-target cytoprotective agent for acute ischemic strokes. In transient middle cerebral artery occlusion (MCAO) rats, SP-8356 significantly reduced brain infarct and edema volumes while improving acute neurological deficits in a dose-dependent manner. Furthermore, SP-8356 improved long-term outcomes, particularly by reducing mortality. These potent cytoprotective effects of SP-8356 were achieved by suppressing the excessive production of free radicals and pro-inflammatory cytokines, reducing the infiltration of inflammatory cells, and mitigating increases in blood-brain barrier permeability. Additional research is needed to determine whether co-administration of SP-8356 can extend the therapeutic time window of reperfusion therapies by mitigating ischemia/reperfusion injury.

Neuronutrition and Its Impact on Post-Stroke Neurorehabilitation: Modulating Plasticity Through Diet

The recovery of neurological deficits after ischemic stroke largely depends on the brain's ability to reorganize its undamaged neuronal circuits and neuronal plasticity phenomena. The consolidated evidence highlights the involvement of the patient's impaired nutritional conditions in post-stroke recovery and unsatisfying rehabilitative outcomes. Standardized nutritional protocols usually applied in hospitalized patients in a rehabilitation setting aim mainly to improve the general health conditions of patients, do not consider the high inter-individual variability in neurorehabilitation outcomes, and are not sufficiently modifiable to provide neuroprotective and restorative dietary patterns that could promote neuronal plasticity and functional recovery during neurorehabilitation. Neuronutrition, an emergent scientific field of neuroscience, represents a valid model of a personalized nutritional approach, assuring, for each patient, nutrients having antioxidant and anti-inflammatory properties, ensuring a balanced microbiota composition, and providing adequate neurotrophic support, essential for improving neuronal plasticity, brain functional recovery, and rehabilitative outcomes. In the present narrative review, we provide an overview of the current knowledge on neuronutrition as an adjuvant strategy of a personalized nutritional approach potentially effective in improving post-stroke neuroplasticity and neurorehabilitation by counteracting or at least limiting post-stroke oxidative/nitrosative stress, neuroinflammation, and gut-brain axis disturbance.

Association between C-reactive protein/albumin ratio and all-cause mortality in patients with stroke: Evidence from NHANES cohort study

BACKGROUND AND AIMS

The inflammatory nutritional status is widely associated with the long-term prognosis of non-fatal stroke. The objective of this study is to examine the correlation between the C-reactive protein to albumin ratio (CAR), a new marker indicating both inflammatory and nutritional status, and the overall mortality rate among stroke patients.

METHODS AND RESULTS

Data were obtained from the National Health and Nutrition Examination Survey (NHANES) database and corresponding public-use mortality data from the linked National Death Index (NDI). The study utilized maximally selected rank statistics to determine the optimal cutoff points for the CAR. Subsequently, participants were stratified into higher- and lower-CAR groups based on these cutoff points. The Kaplan-Meier survival method was used to study overall survival probability. Multivariable Cox proportional regression models were employed to calculate the Hazard Ratio (HR) and corresponding confidence interval (CI). Restricted cubic spline (RCS) model was applied to detect potential non-linear relationship between CAR and mortality risk. Furthermore, stratified and sensitive analyses were performed to examine the robustness and reliability of the results. The study, encompassing 1043 participants with an average age of 64.61 years, identified a cutoff value of 0.32 for CAR, with notable variances observed across gender and age cohorts. Over an average follow-up period of 116 months, 679 instances of all-cause mortality were documented. Kaplan-Meier survival analysis unveiled noteworthy disparities in survival probabilities between groups categorized by high and low CAR levels (p = 0.00081). Continuous CAR analysis consistently demonstrated a positive correlation between elevated CAR values and heightened risk (HR = 1.78 (1.36, 2.33)) of all-cause mortality among stroke patients. Similarly, individuals in the high CAR group exhibited adjusted HR of 1.34 (0.96, 1.89) for all-cause mortality compared to their low CAR counterparts. Subgroup and sensitive analysis consistently reinforced these findings. Smoothing curve fitting further validated CAR's significance as a prognostic indicator of all-cause mortality, indicating a linear relationship.

CONCLUSION

Elevated CAR is associated with increased long-term risk of mortality for individuals who have experienced a stroke, suggesting that CAR could serve as a survival indicator.

Role of NADPH Oxidases in Stroke Recovery

Stroke is one of the most significant causes of death and long-term disability globally. Overproduction of reactive oxygen species by NADPH oxidase (NOX) plays an important role in exacerbating oxidative stress and causing neuronal damage after a stroke. There is growing evidence that NOX inhibition prevents ischemic injury and that the role of NOX in brain damage or recovery depends on specific post-stroke phases. In addition to studies on post-stroke neuroprotection by NOX inhibition, recent reports have also demonstrated the role of NOX in stroke recovery, a critical process for brain adaptation and functional reorganization after a stroke. Therefore, in this review, we investigated the role of NOX in stroke recovery with the aim of integrating preclinical findings into potential therapeutic strategies to improve stroke recovery.

Dexborneol Amplifies Pregabalin's Analgesic Effect in Mouse Models of Peripheral Nerve Injury and Incisional Pain

Pregabalin is a medication primarily used in the treatment of neuropathic pain and anxiety disorders, owing to its gabapentinoid properties. Pregabalin monotherapy faces limitations due to its variable efficacy and dose-dependent adverse reactions. In this study, we conducted a comprehensive investigation into the potentiation of pregabalin's analgesic effects by dexborneol, a neuroprotective bicyclic monoterpenoid compound. We performed animal experiments where pain models were induced using two methods: peripheral nerve injury, involving axotomy and ligation of the tibial and common peroneal nerves, and incisional pain through a longitudinal incision in the hind paw, while employing a multifaceted methodology that integrates behavioral pharmacology, molecular biology, neuromorphology, and lipidomics to delve into the mechanisms behind this potentiation. Dexborneol was found to enhance pregabalin's efficacy by promoting its transportation to the central nervous system, disrupting self-amplifying vicious cycles via the reduction of HMGB1 and ATP release, and exerting significant anti-oxidative effects through modulation of central lipid metabolism. This combination therapy not only boosted pregabalin's analgesic property but also notably decreased its side effects. Moreover, this therapeutic cocktail exceeded basic pain relief, effectively reducing neuroinflammation and glial cell activation-key factors contributing to persistent and chronic pain. This study paves the way for more tolerable and effective analgesic options, highlighting the potential of dexborneol as an adjuvant to pregabalin therapy.

Impact of homocysteine on acute ischemic stroke severity: possible role of aminothiols redox status

BACKGROUND

Acute ischemic stroke (AIS) is one of the most common cerebrovascular diseases which accompanied by a disruption of aminothiols homeostasis. To explore the relationship of aminothiols with neurologic impairment severity, we investigated four aminothiols, homocysteine (Hcy), cysteine (Cys), cysteinylglycine (CG) and glutathione (GSH) in plasma and its influence on ischemic stroke severity in AIS patients.

METHODS

A total of 150 clinical samples from AIS patients were selected for our study. The concentrations of free reduced Hcy (Hcy), own oxidized Hcy (HHcy), free reduced Cys (Cys), own oxidized Cys (cysteine, Cyss), free reduced CG (CG) and free reduced GSH (GSH) were measured by our previously developed hollow fiber centrifugal ultrafiltration (HFCF-UF) method coupled with high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The concentration ratio of Hcy to HHcy (Hcy/HHcy), Cys to Cyss (Cys/Cyss) were also calculated. The neurologic impairment severity of AIS was evaluated using National Institutes of Health Stroke Scale (NIHSS). The Spearman correlation coefficient and logistic regression analysis was used to estimate and perform the correlation between Hcy, HHcy, Cys, Cyss, CG, GSH, Hcy/HHcy, Cys/Cyss and total Hcy with NIHSS score.

RESULTS

The reduced Hcy and Hcy/HHcy was both negatively correlated with NIHSS score in AIS patients with P = 0.008, r=-0.215 and P = 0.002, r=-0.249, respectively. There was no significant correlation of Cys, CG, GSH, HHcy, Cyss, Cys/Cyss and total Hcy with NIHSS score in AIS patients with P value > 0.05.

CONCLUSIONS

The reduced Hcy and Hcy/HHcy, not total Hcy concentration should be used to evaluate neurologic impairment severity of AIS patient.

Ischemic Brain Injury: Involvement of Lipids in the Pathophysiology of Stroke and Therapeutic Strategies

Stroke is a devastating neurological disorder that is characterized by the sudden disruption of blood flow to the brain. Lipids are essential components of brain structure and function and play pivotal roles in stroke pathophysiology. Dysregulation of lipid signaling pathways modulates key cellular processes such as apoptosis, inflammation, and oxidative stress, exacerbating ischemic brain injury. In the present review, we summarize the roles of lipids in stroke pathology in different models (cell cultures, animal, and human studies). Additionally, the potential of lipids, especially polyunsaturated fatty acids, to promote neuroprotection and their use as biomarkers in stroke are discussed.