Specific inhibition of NADPH oxidase 2 modifies chronic epilepsy

Nanoengineered, ultrasmall and catalytic potassium calcium hexacyanoferrate for neuroprotection and temporal lobe epilepsy treatment

Hippocampal sclerosis, characterized by significant hippocampal neuronal loss, oxidative stress, glial cell proliferation, and inflammatory responses, constitutes a pivotal component in the pathogenesis of temporal lobe epilepsy (TLE). Traditional treatment strategies, mainly involving anti-epileptic drugs, face challenges including ineffectiveness, drug tolerance, and adverse reactions, complicating management of the condition. Herein, we design and engineer ultrasmall potassium calcium hexacyanoferrate (III) nanoparticles, designated as KCaHNPs, which feature a broad spectrum of enzymatic activities analogous to superoxide dismutase, catalase, peroxidase, and glutathione peroxidase. KCaHNPs efficiently neutralize excessive reactive oxygen species, mitigate mitochondrial dysfunction, maintain neuronal integrity, and prevent apoptosis. Importantly, KCaHNPs significantly reduce neuronal damage, apoptosis, ferroptosis, and glial cells activation in TLE-afflicted rats, thereby improving spatial and short-term memory, and diminishing epileptic hyperexcitability. Prophylactic deployment of KCaHNPs markedly decreases the frequency and duration of seizures, extends the latency period before the onset of initial seizures, and enhances neural functions within the hippocampal CA3 area. Collectively, these findings underscore the potent therapeutic and prophylactic efficacy of KCaHNPs in mitigating TLE by bolstering cellular defense mechanisms against oxidative stress and inflammation. This innovative approach holds promise as a comprehensive and efficacious strategy for managing temporal lobe epilepsy and potentially other complex neurological disorders.

Targeting NOX2 mitigates seizure susceptibility, oxidative stress, and neuroinflammation in the pentylenetetrazol seizure model

Oxidative stress is a pivotal driver of epileptogenesis and seizure-induced neuronal pathology, with NADPH oxidase 2 (NOX2) serving as a major source of reactive oxygen species (ROS) in the brain. Despite its established role in seizure pathophysiology, the therapeutic implications of selective NOX2 inhibition in epilepsy remain insufficiently explored. Here, we investigate the effect of GSK2795039, a potent NOX2 inhibitor, using both in vitro and in vivo epilepsy models. In vitro, mixed cortical neuroglial cultures were treated with 4-aminopyridine (4-AP) and picrotoxin (PTX) to induce epileptiform activity. Calcium imaging and dihydroethidium (DHE) fluorescence assays revealed that GSK2795039 significantly reduced synchronous Ca2+ oscillations and ROS accumulation. In vivo, adult rats implanted with ECoG transmitters were pretreated with GSK2795039 prior to pentylenetetrazol (PTZ) administration to evoke seizures. ECoG recording and behavioral seizure scoring showed that GSK2795039 pretreatment inhibited the seizure severity, duration and cumulative seizure burden. Molecular analyses, including quantitative PCR and western blotting, revealed a significant downregulation of NOX2 mRNA in both the hippocampus and cortex, although protein levels remained unchanged. Additionally, immunofluorescence and histological staining confirmed that GSK2795039 mitigated oxidative DNA damage, preserved hippocampal neuronal integrity, and differentially modulated pro- and anti-inflammatory cytokine expression. These findings underscore NOX2 inhibition as a compelling neuroprotective strategy and highlight the potential of GSK2795039 to suppress oxidative and inflammatory cascades in epilepsy. Targeting NOX2 may represent a promising avenue for precision therapeutics in oxidative stress-driven epilepsy.

VDAC1 Inhibition Mitigates Inflammatory Status and Oxidative Stress in Epileptic Mice Treated with the Ketogenic Diet

Due to the pleiotropic effects of ketogenic diet (KD) on pathophysiology, including inflammation and oxidative stress, medical personnels have been intensively exploring the application of it in the management of epilepsy. Meanwhile, the voltage-dependent anion channel 1 (VDAC1) is believed to be involved in regulating inflammatory and oxidative stress processes. However, the correlation between KD and VDAC1 in epilepsy has not been elucidated. Pilocarpine-induced chronic epilepsy model was utilized to examine the effects of VDAC1 antagonist VBIT-4 treatment on seizure activity, behavioral changes, inflammation, and oxidative stress under control diet (CD) and KD conditions, respectively. Chronic VBIT-4 administration mitigates seizure activity and behavioral abnormalities of epileptic mice under KD rather than CD conditions. Our further findings demonstrated that VBIT-4 treatment attenuates inflammatory response and oxidative stress in the hippocampi and serum samples of epileptic mice under KD rather than CD. Taken together, our data suggest a critical role of VDAC1 in mediating the anti-seizure efficacy of the KD, shedding light on developing novel therapeutic interventions to seizure control.

GrpEL1 overexpression mitigates hippocampal neuron damage via mitochondrial unfolded protein response after experimental status epilepticus

BACKGROUND

Despite the availability of various antiepileptic treatments, approximately 30 % of epilepsy patients remain refractory to conventional therapies, underscoring the need for neuroprotective strategies. This study investigates the role of GrpEL1 in modulating the mitochondrial unfolded protein response (UPRmt) and its potential protective effects on hippocampal neurons following experimental status epilepticus (SE).

METHODS

The effects of GrpEL1 were assessed in vivo using a Lithium-pilocarpine rat model of SE and in vitro with glutamate-treated HT22 hippocampal cells. Protein expression and interactions were analyzed by Western blot, immunofluorescence, and co-immunoprecipitation. Neuronal survival was evaluated through Nissl staining. Mitochondrial function was evaluated aggresome formation, mitochondrial membrane potential (MMP) assays, mitochondrial oxygen consumption rate (OCR) measurements, and behavioral assessments using the Morris water maze.

RESULTS

In the SE rat model, mtHSP70 levels were significantly upregulated in mitochondria, while GrpEL1 expression remained relatively stable. Overexpression of GrpEL1 led to a reduction in neuronal damage and improved functional recovery post-SE. In vitro, GrpEL1 overexpression enhanced the GrpEL1-mtHSP70 interaction, reduced the accumulation of misfolded proteins, and decreased neuronal apoptosis. Furthermore, GrpEL1 overexpression mitigated mitochondrial dysfunction by preserving MMP and improving mitochondrial bioenergetics, as evidenced by enhanced mitochondrial OCR.

CONCLUSION

GrpEL1 plays a crucial role in maintaining mitochondrial proteostasis and mitigating hippocampal neuronal injury following SE by regulating UPRmt. These findings suggest that GrpEL1 may represent a promising target for therapeutic intervention to protect against seizure-induced neurodegeneration.

Progress in Nanotechnology for Treating Ocular Surface Chemical Injuries: Reflecting on Advances in Ophthalmology

Ocular surface chemical injuries often result in permanent visual impairment and necessitate complex, long-term treatments. Immediate and extensive irrigation serves as the first-line intervention, followed by various therapeutic protocols applied throughout different stages of the condition. To optimize outcomes, conventional regimens increasingly incorporate biological agents and surgical techniques. In recent years, nanotechnology has made significant strides, revolutionizing the management of ocular surface chemical injuries by enabling sustained drug release, enhancing treatment efficacy, and minimizing side effects. This review provides a comprehensive analysis of the etiology, epidemiology, classification, and conventional therapies for ocular chemical burns, with a special focus on nanotechnology-based drug delivery systems in managing ocular surface chemical injuries. Twelve categories of nanocarrier platforms are examined, including liposomes, nanoemulsions, nanomicelles, nanowafers, nanostructured lipid carriers, nanoparticles, hydrogels, dendrimers, nanocomplexes, nanofibers, nanozymes, and nanocomposite materials, highlighting their advantages in targeted delivery, biocompatibility, and improved healing efficacy. Additionally, current challenges and limitations in the field are discussed and the future potential of nanotechnology in treating ocular diseases is explored. This review presents the most extensive examination of this topic to date, aiming to link recent advancements with broader therapeutic strategies.

Suppression of PINK1 autophosphorylation attenuates pilocarpine-induced seizures and neuronal injury in rats

PTEN-induced kinase 1 (PINK1) autophosphorylation triggers the PINK1/Parkin pathway, which is the main mitophagic pathway in the mammalian nervous system. In the present study, we aimed to mechanistically explore the role of PINK1 in pilocarpine-induced status epilepticus (SE) in Sprague-Dawley rats. Evidence from immunohistochemistry, western blotting, biochemical assays, and behavioral testing showed that pilocarpine-induced SE led to increased levels of PINK1 phosphorylation, mitophagy, mitochondrial oxidative stress, neuronal damage and learning and memory deficits. Using shRNA interference to suppress the expression of translocase outer mitochondrial membrane 7, a positive regulator of PINK1 autophosphorylation, lowered the increased levels of phosphorylated PINK1 following pilocarpine administration. It also reduced the levels of mitophagy, mitochondrial oxidative stress and neuronal damage, and attenuated seizure severity and cognitive deficits. In contrast, suppressing the expression of overlapping with the m-AAA protease 1 homolog, a negative regulator of PINK1 autophosphorylation, led to higher levels of phosphorylated PINK1 following pilocarpine administration. It also led to more serious mitophagy, neuronal damage, as well as worsened seizure severity and cognitive deficits. Our results indicate that PINK1 autophosphorylation plays a vital role in epileptic seizures and neuronal injury by mediating mitophagy. Regulating PINK1 autophosphorylation may change the adverse consequences of epilepsy, and may be an effective neuroprotective strategy.

The associations between oxidative stress and epilepsy: a bidirectional two-sample Mendelian randomization study

BACKGROUND

Studies on the association between oxidative stress and epilepsy have yielded varied results. In this study, we aimed to investigate the causal relationship between oxidative stress markers and epilepsy.

METHODS

A bidirectional two-sample Mendelian randomization (MR) study was performed based on publicly available statistics from genome-wide association studies. To explore the causal effects, single nucleotide polymorphisms were selected as instrumental variables. Inverse-variance weighted method was performed for primary analysis, supplemented by weighted median, MR-Egger, simple mode, and weighted mode. Furthermore, sensitivity analyses were performed to detect heterogeneity and pleiotropy.

RESULTS

Our results showed that part of the oxidative stress biomarkers are associated with epilepsy and its subtypes. Zinc is associated with increased risk of epilepsy and generalized epilepsy (odds ratio [OR] = 1.064 and 1.125, respectively). Glutathione transferase is associated with increased risk of generalized epilepsy (OR = 1.055), while albumin is associated with decreased risk of generalized epilepsy (OR = 0.723). Inverse MR analysis revealed that epilepsy is associated with increased levels of uric acid and total bilirubin (beta = 1.266 and 0.081, respectively), as well as decreased zinc level (beta =  - 0.278). Furthermore, generalized epilepsy is associated with decreased ascorbate and retinol levels (beta =  - 0.029 and - 0.038, respectively).

CONCLUSIONS

Our study presented novel evidence of potential causal relationships between oxidative stress and epilepsy, suggesting potential therapeutic targets for epilepsy.

Identification and verification of key molecules in the epileptogenic process of focal cortical dysplasia

Focal cortical dysplasia (FCD) represents a common developmental malformation associated with drug-resistant epilepsy (DRE) among children. However, the exact molecular mechanisms behind this condition are still unclear. In our study, FCD-associated microarray data from the Gene Expression Omnibus (GEO) database were analyzed. A comprehensive series of bioinformatics analyses were conducted, including screening for differentially expressed genes (DEGs), functional enrichment analysis, weighted gene co-expression network analysis (WGCNA), and protein-protein interaction (PPI) analysis. Subsequently, a freezing lesion (FL) rat model was developed to validate expression levels of hub genes along with the molecular pathways behind FCD epileptogenicity. 320 DEGs were identified, and functional enrichment analysis revealed significant enrichment of these DEGs in "Neuroinflammatory response", "Cytokine production involved in immune response", and "Macrophage activation". Ultimately, 5 potential hub genes (CYBB, ITGAM, FCG3A, LY86, and CD86) were pinpointed. Notably, 4 hub genes (CYBB, ITGAM, FCG3A, and CD86) were validated in in vivo experiments, suggesting possible associations with neuroinflammation triggered by microglia. This underscores the tight relationship between microglia-induced neuroinflammation and the pathological progression of epileptic seizures in FCD. ITGAM, FCG3A, CD86, CYBB, and LY86 may emerge as promising candidate biomarkers, influencing diagnostic and therapeutic strategies.

Glucose-6-phosphate dehydrogenase alleviates epileptic seizures by repressing reactive oxygen species production to promote signal transducer and activator of transcription 1-mediated N-methyl-d-aspartic acid receptors inhibition

The pathogenesis of epilepsy remains unclear; however, a prevailing hypothesis suggests that the primary underlying cause is an imbalance between neuronal excitability and inhibition. Glucose-6-phosphate dehydrogenase (G6PD) is a key enzyme in the pentose phosphate pathway, which is primarily involved in deoxynucleic acid synthesis and antioxidant defense mechanisms and exhibits increased expression during the chronic phase of epilepsy, predominantly colocalizing with neurons. G6PD overexpression significantly reduces the frequency and duration of spontaneous recurrent seizures. Furthermore, G6PD overexpression enhances signal transducer and activator of transcription 1 (STAT1) expression, thus influencing N-methyl-d-aspartic acid receptors expression, and subsequently affecting seizure activity. Importantly, the regulation of STAT1 by G6PD appears to be mediated primarily through reactive oxygen species signaling pathways. Collectively, our findings highlight the pivotal role of G6PD in modulating epileptogenesis, and suggest its potential as a therapeutic target for epilepsy.

Anti-epileptic and Neuroprotective Effects of Ultra-low Dose NADPH Oxidase Inhibitor Dextromethorphan on Kainic Acid-induced Chronic Temporal Lobe Epilepsy in Rats

Neuroinflammation mediated by microglia and oxidative stress play pivotal roles in the development of chronic temporal lobe epilepsy (TLE). We postulated that kainic acid (KA)-Induced status epilepticus triggers microglia-dependent inflammation, leading to neuronal damage, a lowered seizure threshold, and the emergence of spontaneous recurrent seizures (SRS). Extensive evidence from our laboratory suggests that dextromethorphan (DM), even in ultra-low doses, has anti-inflammatory and neuroprotective effects in many animal models of neurodegenerative disease. Our results showed that administration of DM (10 ng/kg per day; subcutaneously via osmotic minipump for 4 weeks) significantly mitigated the residual effects of KA, including the frequency of SRS and seizure susceptibility. In addition, DM-treated rats showed improved cognitive function and reduced hippocampal neuronal loss. We found suppressed microglial activation-mediated neuroinflammation and decreased expression of hippocampal gp91phox and p47phox proteins in KA-induced chronic TLE rats. Notably, even after discontinuation of DM treatment, ultra-low doses of DM continued to confer long-term anti-seizure and neuroprotective effects, which were attributed to the inhibition of microglial NADPH oxidase 2 as revealed by mechanistic studies.

Pathological high intraocular pressure induces glial cell reactive proliferation contributing to neuroinflammation of the blood-retinal barrier via the NOX2/ET-1 axis-controlled ERK1/2 pathway

BACKGROUND

NADPH oxidase (NOX), a primary source of endothelial reactive oxygen species (ROS), is considered a key event in disrupting the integrity of the blood-retinal barrier. Abnormalities in neurovascular-coupled immune signaling herald the loss of ganglion cells in glaucoma. Persistent microglia-driven inflammation and cellular innate immune system dysregulation often lead to deteriorating retinal degeneration. However, the crosstalk between NOX and the retinal immune environment remains unresolved. Here, we investigate the interaction between oxidative stress and neuroinflammation in glaucoma by genetic defects of NOX2 or its regulation via gp91ds-tat.

METHODS

Ex vivo cultures of retinal explants from wildtype C57BL/6J and Nox2 -/- mice were subjected to normal and high hydrostatic pressure (Pressure 60 mmHg) for 24 h. In vivo, high intraocular pressure (H-IOP) was induced in C57BL/6J mice for two weeks. Both Pressure 60 mmHg retinas and H-IOP mice were treated with either gp91ds-tat (a NOX2-specific inhibitor). Proteomic analysis was performed on control, H-IOP, and treatment with gp91ds-tat retinas to identify differentially expressed proteins (DEPs). The study also evaluated various glaucoma phenotypes, including IOP, retinal ganglion cell (RGC) functionality, and optic nerve (ON) degeneration. The superoxide (O2-) levels assay, blood-retinal barrier degradation, gliosis, neuroinflammation, enzyme-linked immunosorbent assay (ELISA), western blotting, and quantitative PCR were performed in this study.

RESULTS

We found that NOX2-specific deletion or activity inhibition effectively attenuated retinal oxidative stress, immune dysregulation, the internal blood-retinal barrier (iBRB) injury, neurovascular unit (NVU) dysfunction, RGC loss, and ON axonal degeneration following H-IOP. Mechanistically, we unveiled for the first time that NOX2-dependent ROS-driven pro-inflammatory signaling, where NOX2/ROS induces endothelium-derived endothelin-1 (ET-1) overexpression, which activates the ERK1/2 signaling pathway and mediates the shift of microglia activation to a pro-inflammatory M1 phenotype, thereby triggering a neuroinflammatory outburst.

CONCLUSIONS

Collectively, we demonstrate for the first time that NOX2 deletion or gp91ds-tat inhibition attenuates iBRB injury and NVU dysfunction to rescue glaucomatous RGC loss and ON axon degeneration, which is associated with inhibition of the ET-1/ERK1/2-transduced shift of microglial cell activation toward a pro-inflammatory M1 phenotype, highlighting NOX2 as a potential target for novel neuroprotective therapies in glaucoma management.

Effects of L-Type Voltage-Gated Calcium Channel (LTCC) Inhibition on Hippocampal Neuronal Death after Pilocarpine-Induced Seizure

Epilepsy, marked by abnormal and excessive brain neuronal activity, is linked to the activation of L-type voltage-gated calcium channels (LTCCs) in neuronal membranes. LTCCs facilitate the entry of calcium (Ca2+) and other metal ions, such as zinc (Zn2+) and magnesium (Mg2+), into the cytosol. This Ca2+ influx at the presynaptic terminal triggers the release of Zn2+ and glutamate to the postsynaptic terminal. Zn2+ is then transported to the postsynaptic neuron via LTCCs. The resulting Zn2+ accumulation in neurons significantly increases the expression of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase subunits, contributing to reactive oxygen species (ROS) generation and neuronal death. Amlodipine (AML), typically used for hypertension and coronary artery disease, works by inhibiting LTCCs. We explored whether AML could mitigate Zn2+ translocation and accumulation in neurons, potentially offering protection against seizure-induced hippocampal neuronal death. We tested this by establishing a rat epilepsy model with pilocarpine and administering AML (10 mg/kg, orally, daily for 7 days) post-epilepsy onset. We assessed cognitive function through behavioral tests and conducted histological analyses for Zn2+ accumulation, oxidative stress, and neuronal death. Our findings show that AML's LTCC inhibition decreased excessive Zn2+ accumulation, reactive oxygen species (ROS) production, and hippocampal neuronal death following seizures. These results suggest amlodipine's potential as a therapeutic agent in seizure management and mitigating seizures' detrimental effects.

Medicinal plants for epileptic seizures: Phytoconstituents, pharmacology and mechanisms revisited

ETHNOPHARMACOLOGICAL RELEVANCE

Epilepsy is a neurological disorder that presents with recurring and spontaneous seizures. It is prevalent worldwide, affecting up to 65 million people, with 80% of cases found in lower-income countries. Medicinal plants are commonly employed for managing and treating epilepsy and convulsions due to their unique therapeutic properties. With increasing research and clinical application, medicinal plants are gaining attention globally due to their potent therapeutic effects and fewer side effects. The development of new plant-based antiepileptic/anticonvulsant agents has become a major focus in the pharmaceutical industry.

AIM OF THE REVIEW

This article summarizes recent research on medicinal plants with reported antiepileptic/anticonvulsant effects. It provides pharmacological and molecular mechanism of action information for the crude extracts and related active constituents evaluated in preclinical research for the treatment of epilepsy and convulsions, and offers a reference for the development of future related studies in this area.

MATERIALS AND METHODS

Articles related to ethnopharmacological and antiepileptic studies on plants or natural products from 2018 to 2023 were collected from PubMed, Web of Science and Scopus, etc. using keywords related to epilepsy, medicinal plants, and natural products, etc. RESULTS: Eighty plant species are commonly used to treat epilepsy and convulsions in African and Asian countries. Sixty natural products showing potential for antiepileptic/anticonvulsant effects have been identified from these medicinal plants. These products can be broadly classified as alkaloids, coumarins, flavonoids, saponins, terpenoids and other compounds. The antiepileptic action of plant extracts and their active ingredients can be classified according to their abilities to modulate the GABAergic and glutamatergic systems, act as antioxidants, exhibit anti-neuroinflammatory effects, and provide neuroprotection. In addition, we highlight that some medicinal plants capable of pharmacologically relieving epilepsy and cognition may be therapeutically useful in the treatment of refractory epilepsy.

CONCLUSIONS

The review highlights the fact that herbal medicinal products used in traditional medicine are a valuable source of potential candidates for antiepileptic drugs. This confirms and encourages the antiepileptic/anticonvulsant activity of certain medicinal plants, which could serve as inspiration for further development. However, the aspects of structural modification and optimization, metabolism, toxicology, mechanisms, and clinical trials are not fully understood and need to be further explored.

NOX-induced oxidative stress is a primary trigger of major neurodegenerative disorders

Neurodegenerative diseases (NDDs) causing cognitive impairment and dementia are difficult to treat due to the lack of understanding of primary initiating factors. Meanwhile, major sporadic NDDs share many risk factors and exhibit similar pathologies in their early stages, indicating the existence of common initiation pathways. Glucose hypometabolism associated with oxidative stress is one such primary, early and shared pathology, and a likely major cause of detrimental disease-associated cascades; targeting this common pathology may therefore be an effective preventative strategy for most sporadic NDDs. However, its exact cause and trigger remain unclear. Recent research suggests that early oxidative stress caused by NADPH oxidase (NOX) activation is a shared initiating mechanism among major sporadic NDDs and could prove to be the long-sought ubiquitous NDD trigger. We focus on two major NDDs - Alzheimer's disease (AD) and Parkinson's disease (PD), as well as on acquired epilepsy which is an increasingly recognized comorbidity in NDDs. We also discuss available data suggesting the relevance of the proposed mechanisms to other NDDs. We delve into the commonalities among these NDDs in neuroinflammation and NOX involvement to identify potential therapeutic targets and gain a deeper understanding of the underlying causes of NDDs.

Oxidative Stress and Neurodegeneration in Animal Models of Seizures and Epilepsy

Free radicals are generated in the brain, as well as in other organs, and their production is proportional to the brain activity. Due to its low antioxidant capacity, the brain is particularly sensitive to free radical damage, which may affect lipids, nucleic acids, and proteins. The available evidence clearly points to a role for oxidative stress in neuronal death and pathophysiology of epileptogenesis and epilepsy. The present review is devoted to the generation of free radicals in some animal models of seizures and epilepsy and the consequences of oxidative stress, such as DNA or mitochondrial damage leading to neurodegeneration. Additionally, antioxidant properties of antiepileptic (antiseizure) drugs and a possible use of antioxidant drugs or compounds in patients with epilepsy are reviewed. In numerous seizure models, the brain concentration of free radicals was significantly elevated. Some antiepileptic drugs may inhibit these effects; for example, valproate reduced the increase in brain malondialdehyde (a marker of lipid peroxidation) concentration induced by electroconvulsions. In the pentylenetetrazol model, valproate prevented the reduced glutathione concentration and an increase in brain lipid peroxidation products. The scarce clinical data indicate that some antioxidants (melatonin, selenium, vitamin E) may be recommended as adjuvants for patients with drug-resistant epilepsy.

Evaluation of the Antioxidant Activity of Levetiracetam in a Temporal Lobe Epilepsy Model

Epilepsy is a neurological disorder in which it has been shown that the presence of oxidative stress (OS) is implicated in epileptogenesis. The literature has shown that some antiseizure drugs (ASD) have neuroprotective properties. Levetiracetam (LEV) is a drug commonly used as an ASD, and in some studies, it has been found to possess antioxidant properties. Because the antioxidant effects of LEV have not been demonstrated in the chronic phase of epilepsy, the objective of this study was to evaluate, for the first time, the effects of LEV on the oxidant–antioxidant status in the hippocampus of rats with temporal lobe epilepsy (TLE). The in vitro scavenging capacity of LEV was evaluated. LEV administration in rats with TLE significantly increased superoxide dismutase (SOD) activity, increased catalase (CAT) activity, but did not change glutathione peroxidase (GPx) activity, and significantly decreased glutathione reductase (GR) activity in comparison with epileptic rats. LEV administration in rats with TLE significantly reduced hydrogen peroxide (H2O2) levels but did not change lipoperoxidation and carbonylated protein levels in comparison with epileptic rats. In addition, LEV showed in vitro scavenging activity against hydroxyl radical (HO•). LEV showed significant antioxidant effects in relation to restoring the redox balance in the hippocampus of rats with TLE. In vitro, LEV demonstrated direct antioxidant activity against HO•.

Vascular oxidative stress causes neutrophil arrest in brain capillaries, leading to decreased cerebral blood flow and contributing to memory impairment in a mouse model of Alzheimer’s disease

INTRODUCTION

In this study, we explore the role of oxidative stress produced by NOX2-containing NADPH oxidase as a molecular mechanism causing capillary stalling and cerebral blood flow deficits in the APP/PS1 mouse model of AD.

METHODS

We inhibited NOX2 in APP/PS1 mice by administering a 10 mg/kg dose of the peptide inhibitor gp91-ds-tat i.p., for two weeks. We used in vivo two-photon imaging to measure capillary stalling, penetrating arteriole flow, and vascular inflammation. We also characterized short-term memory function and gene expression changes in cerebral microvessels.

RESULTS

We found that after NOX2 inhibition capillary stalling, as well as parenchymal and vascular inflammation, were significantly reduced. In addition, we found a significant increase in penetrating arteriole flow, followed by an improvement in short-term memory, and downregulation of inflammatory gene expression pathways.

DISCUSSION

Oxidative stress is a major mechanism leading to microvascular dysfunction in AD, and represents an important therapeutic target.

Functional Peptide-Loaded Gelatin Nanoparticles as Eyedrops for Cornea Neovascularization Treatment

Background

Corneal neovascularization (NV) is a process of abnormal vessel growth into the transparent cornea from the limbus and can disturb the light passing through the cornea, resulting in vision loss or even blindness. The use of nanomedicine as an effective therapeutic formulation in ophthalmology has led to higher drug bioavailability and a slow drug release rate. In this research, we designed and explored the feasibility of a new nanomedicine, gp91 ds-tat (gp91) peptide-encapsulated gelatin nanoparticles (GNP-gp91), for inhibiting corneal angiogenesis.

Methods

GNP-gp91 were prepared by a two-step desolvation method. The characterization and cytocompatibility of GNP-gp91 were analyzed. The inhibition effect of GNP-gp91 on HUVEC cell migration and tube formation was observed by an inverted microscope. The drug retention test in mouse cornea was observed by in vivo imaging system, fluorescence microscope, and DAPI/TAMRA staining. Finally, the therapeutic efficacy and evaluation of neovascularization-related factors were conducted through the in vivo corneal NV mice model via topical delivery.

Results

The prepared GNP-gp91 had a nano-scale diameter (550.6 nm) with positive charge (21.7 mV) slow-release behavior (25%, 240hr). In vitro test revealed that GNP-gp91 enhanced the inhibition of cell migration and tube formation capacity via higher internalization of HUVEC. Topical administration (eyedrops) of the GNP-gp91 significantly prolongs the retention time (46%, 20 min) in the mouse cornea. In chemically burned corneal neovascularization models, corneal vessel area with a significant reduction in GNP-gp91 group (7.89%) was revealed when compared with PBS (33.99%) and gp91 (19.67%) treated groups via every two days dosing. Moreover, GNP-gp91 significantly reduced the concentration of Nox2, VEGF and MMP9 in NV's cornea.

Conclusion

The nanomedicine, GNP-gp91, was successfully synthesized for ophthalmological application. These data suggest that GNP-gp91 contained eyedrops that not only have a longer retention time on the cornea but also can treat mice corneal NV effectively delivered in a low dosing frequency, GNP-gp91 eyedrops provides an alternative strategy for clinical ocular disease treatment in the culture.