Free Radical Scavengers Prevent Argininosuccinic Acid-Induced Oxidative Stress in the Brain of Developing Rats: a New Adjuvant Therapy for Argininosuccinate Lyase Deficiency?

Effect of PM2.5 exposure on susceptibility to allergic asthma in elderly rats treated with allergens

Fine particulate matter 2.5 (PM2.5) is a prevalent atmospheric pollutant that is closely associated with asthma. Elderly patients have a high incidence of asthma with a long course of illness. Our previous studies revealed that exposure to PM2.5 diminishes lung function and exacerbates lung damage in elderly rats. In the present study, we investigated whether PM2.5 exposure influences susceptibility to allergic asthma in elderly rats. Brown-Norway elderly rats were treated with ovalbumin (OVA) for different durations before and after PM2.5 exposure. The results from pulmonary function tests and histopathology indicated that early exposure to allergens prior to PM2.5 exposure increased susceptibility to airway hyperresponsiveness and led to severe lung injury in elderly asthmatic rats. Cytokine microarray analysis demonstrated that the majority of cytokines and chemokines were upregulated in OVA-treated rats before and after PM2.5 exposure. Cytological examination showed no change in eosinophil (EOS) counts, yet the amounts of neutrophils (NEU), white blood cells (WBC), lymphocytes (LYM), and monocytes (MON) in the lung lavage fluid of OVA-treated rats were significantly higher than those in control rats before and after PM2.5 exposure, suggesting that PM2.5 affects noneosinophilic asthma in elderly rats. ELISA results from the plasma and lung lavage fluid revealed that the levels of IgG1, IgE, IgG2a and IgG2b were significantly elevated in OVA-treated rats, whereas the level of IgG2b in the lung lavage fluid was significantly lower in rats treated with OVA prior to PM2.5 exposure compared to those treated afterward. A non-targeted metabolomic analysis of plasma identified 202 metabolites, among which 31 metabolites were differentially abundant. Ten metabolites and 11 metabolic pathways were uniquely detected in OVA-treated rats before PM2.5 exposure. Specifically, there were positive or negative correlations between the levels of Th2-associated cytokines (IL-4, IL-5, and IL-13) and six metabolites in the OVA-treated group before PM2.5 exposure, whereas the levels of IL-4 and IL-5 were negatively correlated with five metabolites in the OVA-treated group after PM2.5 exposure. Our findings suggest that PM2.5 exposure could influence the susceptibility of allergic asthma in response to allergens in elderly rats, potentially through changes in plasma metabolites.

Oxidative Stress Associated With Increased Reactive Nitrogen Species Generation in the Liver and Kidney Caused by a Major Metabolite Accumulating in Tyrosinemia Type 1

Tyrosinemia type 1 (TT1) is caused by fumarylacetoacetate hydrolase activity deficiency, resulting in tissue accumulation of upstream metabolites, including succinylacetone (SA), the pathognomonic compound of this disease. Since the pathogenesis of liver and kidney damage observed in the TT1-affected patients is practically unknown, this study assessed the effects of SA on important biomarkers of redox homeostasis in the liver and kidney of adolescent rats, as well as in hepatic (HepG2) and renal (HEK-293) cultured cells. SA significantly increased nitrate and nitrite levels and decreased the concentrations of reduced glutathione (GSH) in the liver and kidney, indicating induction of reactive nitrogen species (RNS) generation and disruption of antioxidant defenses. Additionally, SA decreased the GSH levels and the activities of glutathione peroxidase, glutathione S-transferase, glutathione reductase, and superoxide dismutase in hepatic and renal cells. Noteworthy, melatonin prevented the SA-induced increase of nitrate and nitrite levels in the liver. Therefore, SA-induced increase of RNS generation and impairment of enzymatic and nonenzymatic antioxidant defenses may contribute to hepatopathy and renal disease in TT1.

Metabolic characteristics of ischaemic preconditioning induced performance improvement in Taekwondo athletes using LC‒MS/MS-based plasma metabolomics

In recent years, ischemic preconditioning (IPC) has garnered significant attention in sports research. While IPC has demonstrated positive effects in high-intensity sports such as judo and swimming, its potential benefits for enhancing the performance of Taekwondo athletes have not been extensively studied. This study aimed to investigate the effects of IPC on taekwondo performance and to observe the metabolic characteristics associated with enhancing sports performance via LC‒MS/MS-based plasma metabolomics. Seventeen participants underwent the repeated frequency speed of kick test (FSKT) after IPC, along with pre- and post-exercise plasma metabolite analysis. Differential abundance metabolite analysis, enriched pathway analysis, and weighted gene coexpression network analysis (WGNCA) were employed to delve into metabolic characteristics. The findings highlighted a significant enhancement in FSKT performance in the experimental group. Metabolomic analysis revealed 109 differentially abundant metabolites, including Dl-lactate, hypoxanthine, acetylcarnitine, and acetylsalicylic acid. Enriched pathway analysis revealed pathways such as pentose and glucuronic acid interconversion, ascorbic acid and aldonic acid metabolism, the pentose phosphate pathway (PPP), and the Warburg effect. In conclusion, IPC can significantly increase the specific athletic abilities of Taekwondo athletes, with enhancements linked to anaerobic metabolism, PPP utilization, the Warburg effect for energy production, redox system stability, reduced muscle fatigue, and pain alleviation.

Chronic stress intensify PTZ-induced seizures by triggering neuroinflammation and oxidative stress

BACKGROUND

Epilepsy is a paroxysmal abnormal hypersynchronous electrical discharge characterized by recurrent seizures. It affects more than 50 million people worldwide. Stress is the leading cause of neurodegeneration and can produce seizures that may lead to or aggravate epilepsy. Inflammation plays a vital role in epilepsy by modulating oxidative stress, and levels of neuroinflammatory cytokines including NF-κB, TNF-α, and IL-1β.

METHODS

Stress-induced changes in behavior were evaluated in mice by employing behavioral assessment tests such as an elevated plus maze, light-dark box, open field test, tail suspension test, Y-maze, novel object recognition test, and Morris water maze in pentylenetetrazole (PTZ) kindled mice. Behavioral changes in all these paradigms including seizure score, latency, and frequency showed an increase in symptoms in PTZ (35 mg/kg) induced seizures in stressed mice (RS-PTZ) as compared to PTZ, Stress, and normal animals.

RESULTS

The Enzyme-linked immunosorbent assay (ELISA) results confirmed increased in serum cortisol levels. Histological examinations showed neurodegenerative changes in the hippocampus and cortex regions. The spectrophotometric evaluation showed an increase in oxidative stress by decreasing antioxidant production i.e. reduced glutathione, glutathione -s- transferase, and catalase (CAT), and increasing oxidant levels such as maloaldehyde and nitric oxide. Immunohistochemistry results showed increased expression of NF-κB, TNF-α, and IL-1β in the cortex and hippocampus of mice brains.

CONCLUSIONS

Results from the study conclude that stress increases the likelihood of eliciting an epileptic attack by increasing the level of reactive oxygen species and neuroinflammation.

Analysis of Relationships between Metabolic Changes and Selected Nutrient Intake in Women Environmentally Exposed to Arsenic

Nutrients involved in the metabolism of inorganic arsenic (iAs) may play a crucial role in mitigating the adverse health effects associated with such exposure. Consequently, the objective of this study was to analyze the association between the intake levels of nutrients involved in iAs metabolism and alterations in the metabolic profile during arsenic exposure. The study cohort comprised environmentally exposed women: WL (lower total urinary arsenic (As), n = 73) and WH (higher As, n = 73). The analysis included urinary untargeted metabolomics (conducted via liquid chromatography-mass spectrometry) and the assessment of nutrient intake involved in iAs metabolism, specifically methionine, vitamins B2, B6, and B12, folate, and zinc (based on 3-day dietary records of food and beverages). In the WL group, the intake of all analyzed nutrients exhibited a negative correlation with 5 metabolites (argininosuccinic acid, 5-hydroxy-L-tryptophan, 11-trans-LTE4, mevalonic acid, aminoadipic acid), while in the WH group, it correlated with 10 metabolites (5-hydroxy-L-tryptophan, dihyroxy-1H-indole glucuronide I, 11-trans-LTE4, isovalerylglucuronide, 18-oxocortisol, 3-hydroxydecanedioic acid, S-3-oxodecanoyl cysteamine, L-arginine, p-cresol glucuronide, thromboxane B2). Furthermore, nutrient intake demonstrated a positive association with 3 metabolites in the WL group (inosine, deoxyuridine, glutamine) and the WH group (inosine, N-acetyl-L-aspartic acid, tetrahydrodeoxycorticosterone). Altering the intake of nutrients involved in iAs metabolism could be a pivotal factor in reducing the negative impact of arsenic exposure on the human body. This study underscores the significance of maintaining adequate nutrient intake, particularly in populations exposed to arsenic.

mRNA therapy corrects defective glutathione metabolism and restores ureagenesis in preclinical argininosuccinic aciduria

The urea cycle enzyme argininosuccinate lyase (ASL) enables the clearance of neurotoxic ammonia and the biosynthesis of arginine. Patients with ASL deficiency present with argininosuccinic aciduria, an inherited metabolic disease with hyperammonemia and a systemic phenotype coinciding with neurocognitive impairment and chronic liver disease. Here, we describe the dysregulation of glutathione biosynthesis and upstream cysteine utilization in ASL-deficient patients and mice using targeted metabolomics and in vivo positron emission tomography (PET) imaging using (S)-4-(3-18F-fluoropropyl)-l-glutamate ([18F]FSPG). Up-regulation of cysteine metabolism contrasted with glutathione depletion and down-regulated antioxidant pathways. To assess hepatic glutathione dysregulation and liver disease, we present [18F]FSPG PET as a noninvasive diagnostic tool to monitor therapeutic response in argininosuccinic aciduria. Human hASL mRNA encapsulated in lipid nanoparticles improved glutathione metabolism and chronic liver disease. In addition, hASL mRNA therapy corrected and rescued the neonatal and adult Asl-deficient mouse phenotypes, respectively, enhancing ureagenesis. These findings provide mechanistic insights in liver glutathione metabolism and support clinical translation of mRNA therapy for argininosuccinic aciduria.

Chronic stress but not acute stress decreases the seizure threshold in PTZ-induced seizure in mice: role of inflammatory response and oxidative stress

Seizure is paroxysmal abnormal electrical discharges in the cerebral cortex. Inflammatory pathways and oxidative stress are involved in the pathophysiology of seizures. Stress can induce an oxidative stress state and increase the production of inflammatory mediators in the brain. We investigated the effects of acute and chronic stresses on the seizure threshold in pentylenetetrazol (PTZ)-induced seizures in mice, considering oxidative stress and inflammatory mediators in the prefrontal cortex. In this study, 30 male Naval Medical Research Institute (NMRI) mice were divided into 3 groups, including acute stress, chronic stress, and control groups. PTZ was used for the induction of seizures. The gene expression of inflammatory markers (IL-1β, TNF-α, NLRP3, and iNOS), malondialdehyde (MDA) level, nitrite level, and total antioxidant capacity (TAC) were assessed in the prefrontal cortex and serum. Our results showed that stress could increase the expression of inflammatory cytokines genes and oxidative stress in the prefrontal cortex of the brain and serum following PTZ-induced seizures, which is associated with increased seizure sensitivity and decreased the seizure threshold. The effects of chronic stress were much more significant than acute stress. We concluded that the effects of chronic stress on seizure sensitivity and enhancement of neuroinflammation and oxidative stress are much greater than acute stress.

HBM4EU Chromates Study: Urinary Metabolomics Study of Workers Exposed to Hexavalent Chromium

Exposure to hexavalent chromium Cr(VI) may occur in several occupational activities, placing workers in many industries at risk for potential related health outcomes. Untargeted metabolomics was applied to investigate changes in metabolic pathways in response to Cr(VI) exposure. We obtained our data from a study population of 220 male workers with exposure to Cr(VI) and 102 male controls from Belgium, Finland, Poland, Portugal and the Netherlands within the HBM4EU Chromates Study. Urinary metabolite profiles were determined using liquid chromatography mass spectrometry, and differences between post-shift exposed workers and controls were analyzed using principal component analysis. Based on the first two principal components, we observed clustering by industrial chromate application, such as welding, chrome plating, and surface treatment, distinct from controls and not explained by smoking status or alcohol use. The changes in the abundancy of excreted metabolites observed in workers reflect fatty acid and monoamine neurotransmitter metabolism, oxidative modifications of amino acid residues, the excessive formation of abnormal amino acid metabolites and changes in steroid and thyrotropin-releasing hormones. The observed responses could also have resulted from work-related factors other than Cr(VI). Further targeted metabolomics studies are needed to better understand the observed modifications and further explore the suitability of urinary metabolites as early indicators of adverse effects associated with exposure to Cr(VI).

Resveratrol Promotes Angiogenesis in a FoxO1-Dependent Manner in Hind Limb Ischemia in Mice

Critical limb ischemia (CLI) is a severe form of peripheral artery diseases (PAD) and seriously endangers the health of people. Therapeutic angiogenesis represents an important treatment strategy for CLI; various methods have been applied to enhance collateral circulation. However, the current development drug therapy to promote angiogenesis is limited. Resveratrol (RSV), a polyphenol compound extracted from plants, has various properties such as anti-oxidative, anti-inflammatory and anti-cancer effects. Whether RSV exerts protective effects on CLI remains elusive. In the current study, we demonstrated that oral intake of RSV significantly improved hind limb ischemia in mice, and increased the expression of phosphorylated Forkhead box class-O1 (FoxO1). RSV treatment in human umbilical vein endothelial cells (HUVECs) could increase the phosphorylation of FoxO1 and its cytoplasmic re-localization to promote angiogenesis. Then we manipulated FoxO1 in HUVECs to further verify that the effect of RSV on angiogenesis is in a FoxO1-dependent manner. Furthermore, we performed metabolomics to screen the metabolic pathways altered upon RSV intervention. We found that the pathways of pyrimidine metabolism, purine metabolism, as well as alanine, aspartate and glutamate metabolism, were highly correlated with the beneficial effects of RSV on the ischemic muscle. This study provides a novel direction for the medical therapy to CLI.

S-adenosylmethionine induces mitochondrial dysfunction, permeability transition pore opening and redox imbalance in subcellular preparations of rat liver

S-adenosylmethionine (AdoMet) predominantly accumulates in tissues and biological fluids of patients affected by liver dysmethylating diseases, particularly glycine N-methyltransferase, S-adenosylhomocysteine hydrolase and adenosine kinase deficiencies, as well as in some hepatic mtDNA depletion syndromes, whose pathogenesis of liver dysfunction is still poorly established. Therefore, in the present work, we investigated the effects of S-adenosylmethionine (AdoMet) on mitochondrial functions and redox homeostasis in rat liver. AdoMet decreased mitochondrial membrane potential and Ca²⁺ retention capacity, and these effects were fully prevented by cyclosporin A and ADP, indicating mitochondrial permeability transition (mPT) induction. It was also verified that the thiol-alkylating agent NEM prevented AdoMet-induced ΔΨm dissipation, implying a role for thiol oxidation in the mPT pore opening. AdoMet also increased ROS production and provoked protein and lipid oxidation. Furthermore, AdoMet reduced GSH levels and the activities of aconitase and α-ketoglutarate dehydrogenase. Free radical scavengers attenuated AdoMet effects on lipid peroxidation and GSH levels, supporting a role of ROS in these effects. It is therefore presumed that disturbance of mitochondrial functions associated with mPT and redox unbalance may represent relevant pathomechanisms of liver damage provoked by AdoMet in disorders in which this metabolite accumulates.

Neuronal Death, Glial Reactivity, Microglia Activation, Oxidative Stress and Bioenergetics Impairment Caused by Intracerebroventricular Administration of D-2-hydroxyglutaric Acid to Neonatal Rats

D-2-hydroxyglutaric acid (D-2-HG) accumulates and is the biochemical hallmark of D-2-hydroxyglutaric acidurias (D-2-HGA) types I and II, which comprehend two inherited neurometabolic diseases with severe cerebral abnormalities. Since the pathogenesis of these diseases is poorly established, we tested whether D-2-HG could be neurotoxic to neonatal rats. D-2-HG intracerebroventricular administration caused marked vacuolation in cerebral cortex and striatum. In addition, glial fibrillary acidic protein (GFAP), S-100 calcium binding protein B (S100B) and ionized calcium-binding adapter molecule 1 (Iba-1) staining was increased in both brain structures, suggesting glial reactivity and microglial activation. D-2-HG also provoked a reduction of NeuN-positive cells in cerebral cortex, signaling neuronal death. Considering that disturbances in redox homeostasis and energy metabolism may be involved in neuronal damage and glial reactivity, we assessed whether D-2-HG could induce oxidative stress and bioenergetics impairment. D-2-HG treatment significantly augmented reactive oxygen and nitrogen species generation, provoked lipid peroxidation and protein oxidative damage, diminished glutathione concentrations and augmented superoxide dismutase and catalase activities in cerebral cortex. Increased reactive oxygen species generation, lipoperoxidation and protein oxidation were also found in striatum. Furthermore, the antagonist of NMDA glutamate receptor MK-801 and the antioxidant melatonin were able to prevent most of D-2-HG-induced pro-oxidant effects, implying the participation of these receptors in D-2-HG-elicited oxidative damage. Our results also demonstrated that D-2-HG markedly reduced the respiratory chain complex IV and creatine kinase activities. It is presumed that these deleterious pathomechanisms caused by D-2-HGA may be involved in the brain abnormalities characteristic of early-infantile onset D-2-HGA.