Publications by authors named "Byoung-Joo Gwag"

Microglia/macrophages participate in the development of and recovery from experimental autoimmune encephalomyelitis (EAE), and the macrophage M1 (pro-inflammatory)/M2 (anti-inflammatory) phase transition is involved in EAE disease progression. We evaluated the efficacy of crisdesalazine (a novel microsomal prostaglandin E2 synthase-1 inhibitor) in an EAE model, including its immune-regulating potency in lipopolysaccharide-stimulated macrophages, and its neuroprotective effects in a macrophage-neuronal co-culture system. Crisdesalazine significantly alleviated clinical symptoms, inhibited inflammatory cell infiltration and demyelination in the spinal cord, and altered the phase of microglial/macrophage and regulatory T cells.

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Background And Purpose: Nelonemdaz (Neu2000) has both selective antagonism against 2B subunit of N-methyl-D-aspartate receptor and antioxidant activity. This drug provides sufficient evidence of neuroprotection in acute cerebral ischemia/reperfusion models. This phase III trial aims to determine this effect in patients.

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Purpose: Nonsteroidal anti-inflammatory drugs (NSAIDs) and cyclooxygenase (COX)-2 selective inhibitors are the most widely used drugs to treat pain. Conventional NSAIDs and COX-2 selective inhibitors, however, cause several side effects such as gastric damage, kidney damage, and cardiovascular problems. Our previous study showed that 2-acetoxy-5-(2-4-(trifluoromethyl)-phenethylamino)-benzoic acid ie, flusalazine (also known as ND-07), which exerts dual actions by serving both as an anti-inflammatory agent and a free radical scavenger, is an effective and safe treatment for severe inflammatory diseases in mice.

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Background: Nelonemdaz is a multitarget neuroprotectant that selectively blocks N-methyl-D-aspartate receptors and scavenges free radicals, as proven in preclinical ischemia-reperfusion studies. We aimed to evaluate the safety and efficacy of nelonemdaz in patients with acute ischemic stroke receiving endovascular reperfusion therapy.

Methods: This phase II randomized trial involved participants with large-artery occlusion in the anterior circulation at baseline who received endovascular reperfusion therapy <8 hours from symptom onset at 7 referral stroke centers in South Korea between October 29, 2016, and June 1, 2020.

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Background: Ischemic brain injury is a major hurdle that limits the survival of resuscitated out-of-hospital cardiac arrest (OHCA).

Methods: The aim of this study is to assess the feasibility and potential for reduction of ischemic brain injury in adult OHCA patients treated with high- or low-dose Neu2000K, a selective blocker of N-methyl-D-aspartate (NMDA) type 2B receptor and also a free radical scavenger, or given placebo. This study is a phase II, multicenter, randomized, double-blinded, prospective, intention-to-treat, placebo-controlled, three-armed, safety and efficacy clinical trial.

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Article Synopsis
  • Study highlights the role of reactive astrocytes in Alzheimer's disease (AD) using a new animal model called GiD, which allows manipulation of astrocyte reactivity levels.
  • Severe reactive astrocytes produce excessive hydrogen peroxide, leading to neurodegeneration and cognitive decline, while moderate reactivity does not have this effect.
  • AAD-2004, a hydrogen peroxide scavenger, shows potential in preventing the harmful outcomes associated with severe astrocytic reactivity in AD, suggesting a potential therapeutic pathway.
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Oxidative stress contributes to degeneration of motor neurons in patients with amyotrophic lateral sclerosis (ALS) as well as transgenic mice overexpressing ALS-associated human superoxide dismutase 1 (SOD1) mutants. However, the molecular mechanism by which the ALS-linked SOD1 mutants including SOD1(G93A) induce oxidative stress remains unclear. Here, we show that iron was accumulated in ventral motor neurons from SOD1(G93A)-transgenic mice even at 4 weeks of age, subsequently inducing oxidative stress.

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Amyotrophic lateral sclerosis (ALS) is an adult-onset neurodegenerative disorder characterized by loss of motor neurons. Dominant mutations in the gene for superoxide dismutase 1 (SOD1) give rise to familial ALS by an unknown mechanism. Here we show that genetic deficiency of mammalian sterile 20-like kinase 1 (MST1) delays disease onset and extends survival in mice expressing the ALS-associated G93A mutant of human SOD1.

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Alzheimer's disease (AD) is a neurodegenerative disease that proceeds with the age-dependent neuronal loss, an irreversible event which causes severe cognitive and psychiatric devastations. In the present study, we investigated whether the compound, AAD-2004 [2-hydroxy-5-[2-(4-trifluoromethylphenyl)-ethylaminobenzoic acid] which has anti-oxidant and anti-inflammatory properties, is beneficial for the brain of Tg-betaCTF99/B6 mice, a murine AD model that was recently developed to display age-dependent neuronal loss and neuritic atrophy in the brain. Administration of AAD-2004 in Tg-betaCTF99/B6 mice from 10 months to 18 months of age completely repressed the accumulation of lipid peroxidation in the brain.

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Neu2000 [2-hydroxy-5-(2,3,5,6-tetrafluoro-4 trifluoromethylbenzylamino) benzoic acid] is a dual-acting neuroprotective agent that functions both as a noncompetitive N-methyl-d-aspartate (NMDA) receptor antagonist and a free radical scavenger. In the present study, we investigated the scavenging activity of Neu2000 on various classes of reactive oxygen species and reactive nitrogen species (ROS/RNS) as well as its efficacy for reducing free radicals and oxidative stress/damage induced in spinal cord mitochondrial preparations. Neu2000 exerted scavenging activity against superoxide, nitric oxide, and hydroxyl radicals, and efficiently scavenged peroxynitrite.

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Oxidative stress and inflammation both play major roles in the development of the acute pancreatitis. Currently, a pancreatic enzyme inhibitor with limited efficacy is only clinically available in a few countries, and antioxidants or non-steroidal anti-inflammatory drugs (NSAIDs) provide only partial tissue protection in acute pancreatitis animal models. Here, we introduce a new drug candidate for treating acute pancreatitis named ND-07 [chemical name: 2-acetoxy-5-(2-4-(trifluoromethyl)-phenethylamino)-benzoic acid] that exhibits both potent antioxidative and anti-inflammatory activities.

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While free radicals and inflammation constitute major routes of neuronal injury occurring in amyotrophic lateral sclerosis (ALS), neither antioxidants nor non-steroidal anti-inflammatory drugs have shown significant efficacy in human clinical trials. We examined the possibility that concurrent blockade of free radicals and prostaglandin E(2) (PGE(2))-mediated inflammation might constitute a safe and effective therapeutic approach to ALS. We have developed 2-hydroxy-5-[2-(4-trifluoromethylphenyl)-ethylaminobenzoic acid] (AAD-2004) as a derivative of aspirin.

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Excess activation of ionotropic glutamate receptors and iron is believed to contribute to free radical production and neuronal death following hypoxic ischemia. We examined the possibility that both NMDA receptor activation and iron overload determine spatial and temporal patterns of free radical production after transient middle cerebral artery occlusion (tMCAO) in male Sprague-Dawley rats. Mitochondrial free radical (MFR) levels were maximally increased in neurons in the core at 1 h and 24 h after tMCAO.

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Background: Evidence suggests that rheumatoid arthritis (RA) may enhance or reduce the progression of Alzheimer's disease (AD). The present study was performed to directly explore the effects of collagen-induced rheumatoid arthritis (CIA) on amyloid plaque formation, microglial activation, and microvascular pathology in the cortex and hippocampus of the double transgenic APP/PS1 mouse model for AD. Wild-type or APP/PS1 mice that received type II collagen (CII) in complete Freund's adjuvant (CFA) at 2 months of age revealed characteristics of RA, such as joint swelling, synovitis, and cartilage and bone degradation 4 months later.

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Blood cells are transported into the brain and are thought to participate in neurodegenerative processes following hypoxic ischemic injury. We examined the possibility that transient forebrain ischemia (TFI) causes the blood-brain barrier (BBB) to become permeable to blood cells, possibly via dysfunction and degeneration of endothelial cells in rats. Extravasation of Evans blue and immunoglobulin G (IgG) was observed in the hippocampal CA1-2 areas within 8 h after TFI, and peaked at 48 h.

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Excess activation of ionotropic glutamate receptors, primarily N-methyl-D-aspartate (NMDA) receptors and free radicals, evoke nerve cell death following hypoxic-ischemic brain injury in various animal models. However, clinical trials in stroke patients using NMDA receptor antagonists have failed to show efficacy primarily due to the limited therapeutic time window for neuroprotection and a narrow therapeutic index. In comparison, antioxidants prolonged the time window for neuroprotection in animal models of ischemic stroke and showed greater therapeutic potential in clinical trials for ischemic stroke.

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The purpose of the present study was to evaluate whether chronic cerebral hypoperfusion would affect cognitive status in an Alzheimer mouse model. Behavioral tests and histological evaluations were performed using female Tg2576 mice eight weeks after right common carotid artery occlusion (rCCAO), which is known to induce a type of vascular dementia without neuronal necrosis in nontransgenic mice. Positron emission tomography with (18)F-fluorodeoxyglucose (FDG-PET) was utilized to evaluate metabolic status in the rCCAO-operated brain of nontransgenic mice.

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Article Synopsis
  • Abnormal brain iron levels can lead to oxidative stress and neuronal damage, particularly in the hippocampal CA1 area after a temporary lack of blood flow (transient forebrain ischemia, TFI).
  • Treatment with specific molecules, like Neu2000 and trolox, can reduce free radical production and protect neurons from delayed death, even when given up to 24 hours after reperfusion.
  • The study suggests that excess iron from the bloodstream contributes to long-lasting oxidative stress and neuronal death, indicating that managing iron levels could be a potential therapeutic strategy for protecting the brain after ischemic events.
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The possibility that P2X₇ receptor (P2X₇R) expression in microglia would mediate neuronal damage via reactive oxygen species (ROS) production was examined in the APPswe/PS1dE9 mouse model of Alzheimer's disease (AD). P2X7R was predominantly expressed in CD11b-immunopositive microglia from 3 months of age before Abeta plaque formation. In addition, gp91phox, a catalytic subunit of NADPH oxidase, and ethidium fluorescence were detected in P2X₇R-positive microglial cells of animals at 6 months of age, indicating that P2X₇R-positive microglia could produce ROS.

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Alternative splicing of tau exon 10 influences microtubule assembly and stability during development and in pathological processes of the central nervous system. However, the cellular events that underlie this pre-mRNA splicing remain to be delineated. In this study, we examined the possibility that ischemic injury, known to change the cellular distribution and expression of several RNA splicing factors, alters the splicing of tau exon 10.

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The endoplasmic reticulum (ER) stress results from disrupted protein folding triggered by protein mutation or oxidation, reduced proteasome activity, and altered Ca2+ homeostasis. ER stress is accompanied by activation of the unfolded protein response (UPR) and cell death pathway. We examined if the UPR and cell death pathway would be activated in Alzheimer's disease (AD).

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Background: Most epidemiological studies have reported a significant association between elevated serum levels of uric acid (UA) and increased cardiovascular disease. On the other hand, UA is the most abundant antioxidant in the human body. We hypothesized that UA levels would change noticeably in association with the degree of oxidative stress in acute ischemic stroke.

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The goal of the present study was to examine the neuroprotective and functional significance of targeting both N-methyl-D-aspartate (NMDA) receptor-mediated excitotoxicity and oxidative stress using a dual-acting compound, Neu2000, in rat model of moderate spinal cord injury (SCI). An initial set of experiments was conducted in uninjured rats to study the pharmacokinetic profile of Neu2000 following intraperitoneal and intravenous administration. A second experiment measured free radical production in mitochondria isolated from sham or injured spinal cords of animals receiving vehicle or Neu2000 treatment.

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Article Synopsis
  • Brain inflammation is a risk factor for neurodegenerative diseases like Parkinson's, especially when it occurs in the substantia nigra pars compacta (SNpc).
  • Research found that a lipopolysaccharide (LPS) injection increased inflammation significantly in the SNpc compared to the cortex, leading to a higher number of infiltrating neutrophils and resulting neuronal damage.
  • The study highlights that lower astrocyte density and increased blood-brain barrier permeability in the SNpc may exacerbate the severity of inflammation and contribute to neuronal death in this area.
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To understand the fates of human mesenchymal stem cells (hMSCs) following transplantation into a rodent model of middle cerebral artery occlusion (MCAo), magnetic resonance imaging (MRI) techniques were employed, hMSCs were labeled with ferumoxides (Feridex)--protamine sulfate complexes, which were visualized and examined by MRI up to 10 weeks following transplantation. Migration of the transplanted cells to the infarcted area was further confirmed by histological methods. We found that the hMSCs transplanted in MCAo models possess the capacity to migrate to the infarcted area extensively in both ipsilateral and contralateral injections, exhibiting a pathotropism.

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