Toxic Metabolites Research Articles

Mechanism of action of the toxic proline mimic azetidine 2‐carboxylic acid in plants

SUMMARYPlants have an amazing capacity to outcompete neighboring organisms for space and resources. Toxic metabolites are major players in these interactions, which can have a broad range of effectiveness by targeting conserved molecular mechanisms, such as protein biosynthesis. However, lack of knowledge about defensive metabolite pathways, their mechanisms of action, and resistance mechanisms limits our ability to manipulate these pathways for enhanced crop resilience. Nonproteogenic amino acids (NPAAs) are a structurally diverse class of metabolites with a variety of functions but are typically not incorporated during protein biosynthesis. Here, we investigate the mechanism of action of the NPAA azetidine‐2‐carboxylic acid (Aze), an analog of the amino acid proline (Pro). Using a combination of plate‐based assays, metabolite feeding, metabolomics, and proteomics, we show that Aze inhibits the root growth of Arabidopsis and other plants. Aze‐induced growth reduction was restored by supplementing L‐, but not D‐Pro, and nontargeted proteomics confirm that Aze is misincorporated for Pro during protein biosynthesis, specifically on cytosolically translated proteins. Gene expression analysis, free amino acid profiling, and proteomics show that the unfolded protein response is upregulated during Aze treatment implicating that Aze misincorporation results in accumulation of misfolded proteins triggering a global stress response. This study demonstrates the mechanism of action of Aze in plants and provides a foundation for understanding the biological functions of proteotoxic metabolites.

Discovery of the FXR/CES2 dual modulator LE-77 for the treatment of irinotecan-induced delayed diarrhea

Irinotecan (CPT-11) is a widely utilized topoisomerase I inhibitor in the treatment of colorectal cancer and other malignant tumors. However, severe and even life-threatening dose-limiting toxicity-delayed diarrhea affects the clinical application of CPT-11. The standard treatment for CPT-11-induced delayed diarrhea is prompt use of loperamide (LPA), however LPA can also cause constipation, diarrhea and even intestinal obstruction and has a high failure rate. Carboxylesterase 2 (CES2) is the main enzyme in the intestinal transformation of CPT-11, which can convert CPT-11 into toxic metabolite SN-38 and produce intestinal toxicity. Inhibiting CES2 activity can block the hydrolysis process of CPT-11 in the intestine and reduce SN-38 accumulation. Additionally, Farnesoid X receptor (FXR) agonists have anti-inflammatory, anti-secretory, and protective functions on intestinal barrier integrity that could potentially alleviate diarrhea. In this study, we investigated for the first time the anti-delayed diarrhea effect of FXR agonists, and the first time identified LE-77 as a potent dual modulator that activates FXR and inhibits CES2 through high-throughput screening. In the CPT-11-induced delayed diarrhea model, LE-77 demonstrated a dual modulator mechanism by activating FXR and inhibiting CES2, thereby reducing the accumulation of SN-38 in the intestine, alleviating intestinal inflammation, preserving intestinal mucosal integrity, and ultimately alleviating delayed diarrhea

Aflatoxin awareness and preventive agricultural practices are key to adoption of biocontrol among maize smallholder farmers in Tanzania.

Aflatoxins are toxic secondary metabolites produced by Aspergillus species that infect staple foods like maize causing threat to public health and economic impacts. The use of atoxigenic Aspergillus species is considered one of the promising technologies to prevent aflatoxin contamination in maize. Tanzania approved the use of aflatoxin biocontrol (Aflasafe®) in 2018 and introduced it to eight districts. Adoption and effectiveness of this technology depend on many factors including application of pre- and post-harvest practices. There is scant information on awareness of biocontrol and factors which influence the adoption and effectiveness of this technology. A cross-sectional study was conducted in Tanzania to assess awareness and identify factors influencing adoption of the technology. Data was collected from 334 smallholder farmers in Kiteto and Chemba districts and analyzed using SPSS version 20; p-values < 0.05 using a two-tailed test were considered statistically significant. Results indicated 95.4% are not aware and that only 2.7% of the farmers had used biocontrol technology. The use of biocontrol was significantly associated with high income level (p = 0.001) and exposure to print media (p = 0.03) and radio (p = 0.008). The use of hybrid seed (p = 0.01), grazing (p = 0.017), and rotation of crops on yearly basis (p = 0.024) were also significantly associated with the use of biocontrol. Income limits the use of biocontrol, requiring government subsidies for Aflasafe and a premium market for aflatoxin-free maize. Aflatoxin awareness and sensitization on adherence to good pre-harvest practices should be emphasized to enhance adoption of the technology.

Importance of benzoyltransferase GcnE and lysine benzoylation of alcohol dehydrogenase AdhB in pathogenesis and aflatoxin production in Aspergillus flavus.

Lysine benzoylation (Kbz) is a newly identified post-translational modification associated with active transcription and metabolism in eukaryotes. However, whether Kbz exists in pathogenic fungi and its function remains unknown. Here, we demonstrated for the first time that Kbz is present in Aspergillus flavus and identified 60 benzoylated sites on 46 benzoylated proteins by global benzoylome analysis. Our data demonstrated that alcohol dehydrogenase B (AdhB) is regulated by benzoylation on lysine 321 (K321), and mutations of Kbz site in AdhB significantly reduced the alcohol dehydrogenase activity in vivo and in vitro. Both adhB deletion mutant and benzoylated site mutants (K321R and K321A) exhibited similar phenotype, including decreased conidiation and seed colonization, increased sclerotia formation and aflatoxin production, and more sensitive to cell wall damage stress. We also found that GcnE has benzoyltransferase activity in vitro and in vivo, and its repression leads to decreased Kbz level and enzymatic activity of AdhB. The catalytic site E139 is important for the benzoyltransferase function of GcnE. Our study uncovers a previously unknown mechanism by which benzoylation regulates AdhB activity to affect the development, secondary metabolism, pathogenicity, and stress response of A. flavus. Meanwhile, it points out the important role of Kbz in the pathogenicity of pathogenic fungi.IMPORTANCEAspergillus flavus is a ubiquitous opportunistic pathogen of plants and animals, which produces carcinogenic and toxic secondary metabolite aflatoxin. A. flavus and aflatoxin contamination have emerged as a global food safety concern. Currently, post-translational modification plays crucial modulatory roles in the fungal development and virulence, but the role of benzoylation in fungal pathogenicity remains undetermined, which limits the development of prevention and control technique. Here, we first identified 46 benzoylated proteins in A. flavus, and found that benzoyltransferase GcnE exerted effects on pathogenicity and aflatoxin production by regulating the benzoylation of AdhB. This finding not only provided valuable information for prevention and control of A. flavus contamination, but also offered basic knowledge for investigation of the regulation mechanism of secondary metabolism in other fungi.

Inactivation of Aspergillus Species and Degradation of Aflatoxins in Water Using Photocatalysis and Titanium Dioxide

Aflatoxins (AF) are highly toxic secondary metabolites produced by various species of Aspergillus, posing significant health risks to humans and animals. The four most prominent types are aflatoxin B1 (AFB1), aflatoxin B2 (AFB2), aflatoxin G1 (AFG1), and aflatoxin G2 (AFG2). These mycotoxins are prevalent in various environments, including water sources and food products. Among these mycotoxins, AFB1 is recognized as the most toxic, mutagenic, and carcinogenic to humans. Consequently, most efforts to mitigate the impact of AF have been focused on AFB1, with photocatalysis emerging as a promising solution. Recent research has demonstrated that using semiconductor photocatalysis, particularly titanium dioxide (TiO2), combined with UV–visible irradiation significantly enhances the efficiency of AF degradation. TiO2 is noted for its high activity under UV irradiation, non-toxicity, and excellent long-term stability, making it a favorable choice for photocatalytic applications. Furthermore, TiO2 combined with visible light has demonstrated the ability to reduce AF contamination in food products. This article summarizes the working conditions and degradation rates achieved, as well as the advantages, limitations, and areas of opportunity of these methodologies for the degradation of AF and preventing their production, thereby enhancing food and water safety.

Mitochondrial dysfunction in Parkinson's disease.

The exact cause of nigral cell death in Parkinson's disease (PD) is still unknown. However, research on MPTP-induced experimental parkinsonism has significantly advanced our understanding. In this model, it is widely accepted that mitochondrial respiratory failure is the primary mechanism of cell death. Studies have shown that a toxic metabolite of MPTP inhibits Complex I and alpha-ketoglutarate dehydrogenase activities in mitochondria. Since then, many research groups have focused on mitochondrial dysfunction in PD, identifying deficiencies in Complex I or III in PD patients' brains, skeletal muscle, and platelets. There is some debate about the decline in mitochondrial function in peripheral organs. However, since α-synuclein, the main component protein of Lewy bodies, accumulates in peripheral organs, it is reasonable to consider PD a systemic disease. Additionally, mutant mitochondrial DNA with a 4,977 base pair deletion has been found in the brains of PD patients, suggesting that age-related accumulation of deleted mtDNA is accelerated in the striatum and may contribute to the pathophysiology of PD. While the cause of PD remains unknown, mitochondrial dysfunction is undoubtedly a factor in cell death in PD. In addition, the causative gene for familial PD, parkin (now PRKN), and PTEN-induced putative kinase 1 (PINK1), both gene products are also involved in mitochondrial quality control. Moreover, we have successfully isolated and identified CHCHD2, which is involved in the mitochondrial electron transfer system. There is no doubt that mitochondrial dysfunction contributes to cell death in PD.

Human glyoxylate metabolism revisited: New insights pointing to multi-organ involvement with implications for siRNA-based therapies in primary hyperoxaluria.

Glyoxylate is a toxic metabolite because of its rapid conversion into oxalate, as catalyzed by the ubiquitous enzyme lactate dehydrogenase. This requires the presence of efficient glyoxylate detoxification systems in multiple subcellular compartments, as glyoxylate is produced in peroxisomes, mitochondria, and the cytosol. Alanine glyoxylate aminotransferase (AGT) and glyoxylate reductase/hydroxypyruvate reductase (GRHPR) are the key enzymes involved in glyoxylate detoxification. Bi-allelic mutations in the genes coding for these enzymes cause primary hyperoxaluria type 1 (PH1) and 2 (PH2), respectively. Glyoxylate is derived from various sources, including 4-hydroxyproline, which is degraded in mitochondria, generating pyruvate and glyoxylate, as catalyzed by the mitochondrial enzyme 4-hydroxy-2-oxoglutarate aldolase (HOGA); however, counterintuitively, a defect in HOGA1 is the molecular basis of primary hyperoxaluria type 3 (PH3). Irrespective of its underlying cause, hyperoxaluria in humans leads to nephrocalcinosis, recurrent urolithiasis, and kidney damage, which may culminate in kidney failure requiring combined liver-kidney transplantation in severely affected patients. In the past few years, therapeutic options, especially for primary hyperoxaluria type 1 (PH1), have greatly been improved thanks to the introduction of two RNAi-based therapies that inhibit either the production of glycolate oxidase (lumasiran) or lactate dehydrogenase (nedosiran). While lumasiran only targets PH1 patients, nedosiran was specifically developed to target all three subtypes of PH. Inspired by the findings reported in the literature that nedosiran effectively reduced urinary oxalate excretion in PH1 patients but not in PH2 or PH3 patients, we have now revisited glyoxylate metabolism in humans and performed a thorough literature study which revealed that glyoxylate/oxalate metabolism is not confined to the liver but instead involves multiple different organs. This new view on glyoxylate/oxalate metabolism in humans may well explain the disappointing results of nedosiran in PH2 and PH3, and provides new clues for the future generation of new therapeutic strategies for PH2 and PH3.

Efficacy and safety of switching therapy from chenodeoxycholic acid to cholic acid in Japanese patients with bile acid synthesis disorders

ObjectivesThis study aimed to assess the safety and efficacy of cholic acid (CA) treatment over 74 weeks in Japanese patients with inherited enzymatic bile acid synthesis disorders (BASD). MethodsThis phase 3, open-label, single-arm study enrolled four Japanese patients diagnosed with BASD, including two with 3β-hydroxy-Δ5-C27-steroid dehydrogenase/isomerase (HSD3B7) deficiency and two with Δ4–3-oxosteroid 5β-reductase (SRD5B1) deficiency. The patients had received chenodeoxycholic acid (CDCA) treatment but were switched to CA treatment. Treatment efficacy was evaluated by measuring serum and urinary bile acid levels and liver-related biomarkers, and adverse events were evaluated to monitor safety. ResultsThe daily CA doses ranged from 3.8 to 13.7 mg/kg/day. Laboratory values of liver-related biomarkers were maintained within normal ranges or improved. Bile acid analysis revealed CDCA replacement with CA in serum within the initial few weeks of CA treatment. Urinary concentrations of toxic bile acid metabolites associated with liver damage were higher than serum. Adverse effects from CA treatment were mild to moderate, and no treatment discontinuations were due to adverse events. ConclusionsCA treatment over 74 weeks resulted in favorable efficacy and safety outcomes in Japanese patients with BASD, consistent with previous studies. These results support the utility of CA as a therapeutic option for Japanese patients with BASD.

Sox6 and ALDH1A1 Truncation by Asparagine Endopeptidase Defines Selective Neuronal Vulnerability in Parkinson's Disease.

Dopaminergic neurons in the substantia nigra pars compacta (SNpc) demonstrate regionally selective susceptibility in Parkinson's disease (PD) compared to those in the ventral tegmental area (VTA). However, the molecular mechanism for this distinct vulnerability remains unclear. Here, it is shown that Legumain, also known as asparagine endopeptidase (AEP), is activated in a subgroup of SRY-box transcription factor 6 /Aldehyde dehydrogenase 1 family member A1, (Sox6+/ALDH1A1+) neurons in the ventral tier of the SNpc and cleaves Sox6 and ALDH1A1, leading to repression of Special AT-rich sequence binding protein 1 (Satb1) that is a dimeric/tetrameric transcription factor specifically binding to AT-rich DNA sequences, and toxic dopamine metabolite accumulation. AEP cuts Sox6 and ALDH1A1 in dopaminergic neurons that project to the locus coeruleus (LC), abolishing Sox6's transcriptive and ALDH1A1's enzymatic activities. Co-expressing AEP-truncated Sox6 and ALDH1A1 fragments in 3-month-old A53T SNCA transgenic mice accelerates dopamine degeneration, whereas expressing AEP-resistant Sox6 N336A/N446A and ALDH1A1 N220A mutants alleviates rotenone-induced PD pathologies. Hence, different circuitries and intrinsic properties of dopaminergic neurons in the SNpc and VTA render differential predispositions in PD.

Flux balance analysis and peptide mapping elucidate the impact of bioreactor pH on Chinese hamster ovary (CHO) cell metabolism and N-linked glycosylation in the fab and Fc regions of the produced IgG

Culture conditions have a profound impact on therapeutic protein production and glycosylation, a critical therapeutic-quality attribute, especially for monoclonal antibodies (mAbs). While the critical culture parameter of pH has been known since the early 1990s to affect protein glycosylation and production, detailed glycan and metabolic characterization and mechanistic understanding are critically lacking. Here, Chinese Hamster Ovary (CHO) cells were grown in bioreactors at pH 6.75, 7, and 7.25 (± 0.03) to examine how pH affects cell metabolism and site-specific N-linked glycosylation of the produced broadly neutralizing anti-HIV IgG1 mAb. VRC01 has N-linked glycosylation sites in both the Fc region and the Fab region, a situation not previously examined with respect to mAb glycosylation as affected by culture conditions. Using parsimonious Flux Balance Analysis (pFBA) and Flux Variability Analysis (FVA), we dissect and quantitate the impact of pH on cell growth, glucose/lactate metabolism, accumulation of the toxic metabolite ammonia, IgG production rates, and nonessential amino acid metabolism. pFBA revealed that beyond the established mechanism of glutamine conversion to glutamate, ammonia is also produced by the reaction converting serine to pyruvate, especially in the later phases of culture. pFBA also provided insights into the switch from ammonia production to consumption, notably due to depletion of glutamine, and consumption of glutamate and aspartate. We document that culture duration and pH alter the complex bimodal patterns (production/uptake) of several essential and non-essential amino acids. Site-specific N-linked glycan analysis using glycopeptide mapping demonstrated that pH significantly affects the glycosylation profiles of the two IgG1 sites. Fc region glycans were completely fucosylated but did not contain any sialylation. The Fab region glycans were not completely fucosylated but contained sialylated glycans. Bioreactor pH affected both the fucosylation and sialylation indexes in the Fab region and the galactosylation index of the Fc region. However, fucosylation in the Fc region was unaffected thus demonstrating that the effect of pH on site-specific N-linked glycosylation is complex.

Effects of microplastics on 3,5-dichloroaniline adsorption, degradation, bioaccumulation and phytotoxicity in soil-chive systems.

Microplastics (MPs) and pesticides are two pollutants of concern in agricultural soils. 3,5-dichloroaniline (3,5-DCA), a highly toxic metabolite of dicarboximide fungicides, commonly co-exists with MPs and poses a risk to the environment and food safety. Batch adsorption and soil incubation experiments were employed to investigate the effects of polyethylene (PE) and polylactic acid (PLA) MPs on the environmental behavior of 3,5-DCA in soil. Chive (Allium ascalonicum) was used as the experimental plant, a pot experiment was conducted to examine the effects of individual or combined exposure to MPs and 3,5-DCA on plant 3,5-DCA bioaccumulation, growth characteristics, and phytotoxicity. The results showed that PE- and PLA-MPs increased the adsorption capacity of soil to 3,5-DCA and prolonged the degradation half-life of 3,5-DCA by 6.24 and 16.07d, respectively. Two MPs partially alleviated the negative effects of 3,5-DCA on the root length and fresh weight of chives, while PE-MPs had a positive and dose-dependent impact on the contents of photosynthetic pigment in chive leaves. Co-exposure to 3,5-DCA and MPs increased residues of 3,5-DCA in soil and chive roots but had no significant effect on 3,5-DCA residues in chive stems or leaves. Moreover, 3,5-DCA residues in PLA-MP soil were consistently higher than those in PE-MP soil. Conclusively, MPs altered the 3,5-DCA adsorption and degradation behavior in soil, as well as its bioaccumulation in chives. Co-exposure to MPs and 3,5-DCA had dose-dependent and MP-specific effects on chive plant development and phytotoxicity.

Neurodegenerative biomarkers and inflammation in patients with propionic and methylmalonic acidemias: effect of L-carnitine treatment.

Propionic and methylmalonic acidemias (PAcidemia and MMAcidemia, respectively) are genetic disorders characterized by acute metabolic decompensation and neurological complications. L-carnitine (LC) is effective in reducing toxic metabolites that are related to the pathophysiology of these diseases. Therefore we investigated biomarkers of inflammation (cytokines and C-reactive protein (CRP)), neurodegeneration (BDNF, NCAM-1 and cathepsin-D) and biomolecules oxidation (sulfhydryl content and thiobarbituric acid-reactive species (TBARS)), as well as carnitine concentrations in untreated patients with PAcidemia and MMAcidemia, in patients under treatment with LC and a protein-restricted diet for until 2 years and in patients under the same treatment for more than 2 years. It was verified an increase of CRP, IL-6, IL-8, TNF-α, IL-10, NCAM-1 and cathepsin-D in untreated patients compared to controls. On the other hand, reduced levels of TNF-α, CRP, IL-10, NCAM-1 and cathepsin-D were found in plasma from treated patients, as well as increased concentrations of LC. Furthermore, oxidative biomarkers were increased in untreated patients and were normalized with the prolonged treatment with LC. In conclusion, this work shows, for the first time, that inflammatory and neurodegenerative peripheral biomarkers are increased in patients with PAcidemia and MMAcidemia and that treatment with LC is effective to protect against these alterations.

Co-Occurrence of Mycotoxins in the Diet and in the Milk of Dairy Cows from the Southeast Region of Brazil.

Mycotoxins are toxic fungi secondary metabolites that develop on feedstuffs and can be transferred into milk, thus representing a public health risk. The objective of this study was to assess the co-occurrence of mycotoxins in the diet and in the milk of dairy cows from the southeast region of Brazil. Samples of total mixed ration (TMR, n = 70) and milk (n = 70) were collected in dairy farms and subjected to multi-mycotoxin analysis using liquid chromatography coupled to tandem mass spectrometry. The aflatoxins (AFs), ochratoxin A (OTA), and T-2 and HT-2 toxins were not detected in TMR samples. In contrast, fumonisins (FBs), zearalenone (ZEN), and deoxynivalenol (DON) were detected in 100, 93, and 24% of TMR samples at mean levels of 336.7 ± 36.98, 80.32 ± 16.06 µg/kg and 292.1 ± 85.68 µg/kg, respectively. Ninety-two percent of TMR samples exhibited co-occurring mycotoxins. In milk, 54% of samples (n = 38) had detectable levels of mycotoxin, while 43% (n = 30) contained two or more types of mycotoxins. DON, FB, and ZEN metabolites (α-zearalenol and β-zearalenol) were the most frequent mycotoxins detected in the milk samples analyzed, at mean concentrations of 0.562 ± 0.112, 2.135 ± 0.296 µg/kg, 2.472 ± 0.436 µg/kg, and 0.343 ± 0.062 µg/kg, respectively. However, none of the analyzed milk samples had levels higher than the maximum permitted limit for AFM1 in Brazil (0.5 µg/L). The results of this trial highlight the concern about the co-occurrence of multiple mycotoxins in TMR and in milk, due to the possible additive or synergistic effects of these compounds. The presence of co-occurring mycotoxins in milk underscores the need for stringent preventive practices to avoid mycotoxin contamination in the diet of dairy cows in Brazil.

Biochemical characterization of the human ubiquitous glucose-6-phosphatase in neutrophil granulocytes.

Glucose-6-phosphatase-β (G6PC3) is a ubiquitous phosphatase present in the endoplasmic reticulum, which, unlike G6PC1, is not responsible for maintaining blood glucose level under starvation. Recently, G6PC3 has been shown to play an important role in neutrophil granulocytes, eliminating the toxic metabolite 1,5-anhydroglucitol-6-phosphate. The present study aimed to look for alternative substrates for the enzyme and outline the expression changes in the parts of this multicomponent system during neutrophil granulocyte differentiation. We determined the kinetic characteristics of recombinant human G6PC3 towards different sugar phosphates, and the transport of these compounds was also measured in rat liver microsomes. We found that all investigated sugar phosphates are substrates for G6PC3, although their microsomal transport is much slower than that of glucose-6-phosphate. Using the HL-60 promyelocytic leukemia cell line as an in vitro model system for myeloid differentiation, we found no significant differences in enzyme expression and phosphatase activity latency between undifferentiated and differentiated cells. Our results provide novel insights into the possible role of G6PC3 in the dephosphorylation of alternative sugar phosphates or their metabolites synthesized in the endoplasmic reticulum and confirm the potential feature of the enzyme in the promyelocytic stage as well. These findings contribute to our knowledge of intracellular carbohydrate metabolism of neutrophil granulocytes, which facilitates further research directions to better understand the underlying mechanisms of neutropenias.

Pleurotus spp.-an effective way in degradation mycotoxins? A comprehensive review.

Mycotoxins-secondary metabolites produced by filamentous fungal species-occur as a global problem in agriculture due to the reduction in crop quality and the negative effects on human and animal health. There is a need to develop environment-friendly methods of detoxification. In recent years, a number of biological methods for the removal/degradation of mycotoxins have been described. One of them-particularly interesting due to its high effectiveness-is mycoremediation, which involves the ability of Pleurotus spp. mushrooms to remove toxic contaminants from the environment and food. Pleurotus spp. biosynthesizes ligninolytic enzymes, such as laccase and manganese peroxidase that are the main factors of enzymatic degradation of various pollutants, including mycotoxins. The degradation process of mycotoxins (especially aflatoxins) with the participation of isolated enzymes reaches approximately 30-100%, depending on the culture conditions, substrate, and mediators used. In the food industry, their application may include, among others, the detoxification of animal feed from mycotoxins or fermentation products (e.g., juices and wines). While these applications are promising, they require further research to expand toxicological knowledge and optimize their use. This review presents current research on this new and very promising topic related to the use of edible Pleurotus spp. mushrooms in the process of biological degradation of toxic fungal metabolites.

Inborn errors of metabolism in neonates and pediatrics on varying dialysis modalities: a systematic review and meta-analysis.

Some inborn errors of metabolism (IEMs) resulting in aberrations to blood leucine and ammonia levels are commonly treated with kidney replacement therapy (KRT). Children with IEMs require prompt treatment, as delayed treatment results in increased neurological and developmental morbidity. Our systematic review in neonates and pediatrics evaluates survival rates and reductions in ammonia and leucine levels across different KRT modalities (continuous KRT (CKRT), hemodialysis (HD), peritoneal dialysis (PD)). A literature search was conducted through PubMed, Web of Science, and Embase databases for articles including survival rate and toxic metabolite clearance data in pediatric patients with IEM undergoing KRT. Cross-sectional, prospective, and retrospective studies with survival rates reported in patients with IEM with an intervention of CKRT, PD, or HD were included. Studies with patients receiving unclear or multiple KRT modalities were excluded. Analysis variables included efficacy outcomes [% reduction in ammonia (RIA) from pre- to post-dialysis and time to 50% RIA] and mortality. The Newcastle Ottawa Risk of Bias quality assessment was used to assess bias. All statistical analyses were performed with MedCalc Statistical Software version 19.2.6. A total of 37 studies (n = 642) were included. The pooled proportion (95% CI) of mortality on CKRT was 24.84% (20.93-29.08), PD was 34.42% (26.24-43.33), and HD 34.14% (24.19-45.23). A lower trend of pooled (95% CI) time to 50% RIA was observed with CKRT [6.5 (5.1-7.8)] vs. PD [14.4 (13.3-15.5)]. A higher mortality was observed with greater plasma ammonia level before CKRT (31.94% for ≥ 1000µmol/L vs. 15.04% for < 1000µmol/L). Despite the limitations in sample size, trends emerged suggesting that CKRT may be associated with lower mortality rates compared to HD or PD, with potential benefits including prevention of rebound hyperammonemia and improved hemodynamic control. While HD showed a trend towards faster achievement of 50% RIA, all modalities demonstrated comparable efficacy in reducing ammonia and leucine levels. CRD42023418842.

ROLE OF NF-κB ACTIVATION IN CHANGES OF NITRIC OXIDE PRODUCTION IN SKELETAL MUSCLES DURING METABOLIC SYNDROME

Nitric oxide, as a signaling molecule, plays an ambiguous role in many pathological processes. On the one hand, nitric oxide is necessary for maintaining the tone of the vascular wall of arteries and prevents the development of ischemia in various organs and skeletal muscles in particular. On the other hand, excessive production of nitric oxide in the tissue can contribute to the formation of toxic metabolites, such as peroxynitrite that leads to the development of nitrosative damage to various organs and tissues. Metabolic syndrome is also one of the diseases accompanied by disturbances in the nitric oxide production system. Currently, the sources of nitric oxide production, the predominant ways of its metabolism, and the influence of the transcription factor NF-κB on these processes in skeletal muscles under the conditions of the metabolic syndrome are insufficiently studied. The purpose of this study is to study the effect of an inhibitor of the activation of the transcription factor NF-κB on the production of nitric oxide and the concentration of its metabolites in the biceps femoris muscle of rats under the conditions of modeling the metabolic syndrome. The experimental study was carried out on male Wistar rats weighing 200-260 g. The animals were randomly divided into 4 groups of 6 animals each. Animals of group 1 (control group) received a standard vivarium diet. In group 2 (metabolic syndrome), in addition to the standard diet, the animals received a 20% fructose solution as their sole source of drinking water for 60 days. In group 3, the animals were given a standard vivarium diet and were injected intraperitoneally with ammonium pyrrolidine dithiocarbamate at a dose of 76 mg/kg, three times a week for 60 days. Group 4 received the same diet as group 2 along with the injections administered in group 3. In 10% homogenate of the biceps femoris muscle, the following were determined: total NO-synthase activity, activity of constitutive and inducible isoforms of NO-synthase, arginase activity, aitrate- and nitrite reductase activity, concentrations of nitrite, peroxynitrite, nitrosothiols, and sulfides. The administration of ammonium pyrrolidinedithiocarbamate during metabolic syndrome simulation resulted in a reduction in total NO-synthase activity and inducible NO-synthase activity by 33.85% and 34.66%, respectively, compared to the metabolic syndrome group; arginase activity decreased by 37.56%, while nitrate and nitrite reductase activities were reduced by 19.29% and 47.71%, respectively; nitrite concentration increased by 21.77%, peroxynitrite concentration decreased by 32.05%, nitrosothiol concentration increased by 29.27%, and sulfide concentration decreased by 17.39% compared to the group with metabolic syndrome. Activation of the transcription factor NF-κB under metabolic syndrome conditions leads to increased nitric oxide production through both L-arginine-dependent and L-arginine-independent pathways in the biceps femoris muscle, enhances arginase activity, and results in elevated peroxynitrite formation.

Herbo-vitamin medicine Livogrit Vital ameliorates isoniazid induced liver injury (IILI) in human liver (HepG2) cells by decreasing isoniazid accumulation and oxidative stress driven hepatotoxicity

BackgroundTuberculosis (TB) is a leading cause of infection related mortality. Isoniazid is one of the frontline drugs for anti-TB therapy. Hepatotoxicity induced by isoniazid is a major cause of drug-discontinuation which may lead to development of resistant TB or increased mortality.PurposeTo characterize pharmacological properties of plant-based prescription medicine, Livogrit Vital (LVV) against isoniazid-induced liver injury (IILI) using HepG2 cells.MethodPhytometabolite characterization of LVV was performed by High-performance liquid chromatography (HPLC). The effects of LVV on cytosafety, IC50 shift, oxidative stress, ER stress, apoptosis, liver injury markers, and accumulation of isoniazid and hydrazine was performed on HepG2 cells induced with isoniazid. Silymarin was used as the positive control.ResultsHPLC based phytometabolite characterization of LVV revealed the presence of several anti-oxidant, anti-apoptotic, and hepatoprotective compounds. In isoniazid-induced HepG2 cells, LVV reduced cytotoxicity of isoniazid and shifted its IC50 value. Treatment with LVV reduced ROS generation and lipid peroxidation; enhanced GSH enzyme levels in isoniazid-induced HepG2 cells. As per the mechanistic evaluation, LVV modulated gene expression level of Caspase-3, FGF21, and IRE-1α. LVV treatment also normalized isoniazid-induced elevated Caspase-3 activity and cPARP1 protein levels, indicating its potentials to regulate liver cell apoptosis. Concomitantly, biomarkers of hepatotoxicity, ALT and GGT, also decreased by LVV treatment. Interestingly, LVV treatment reduced intracellular accumulation of isoniazid and its toxic metabolite hydrazine, in isoniazid-stimulated HepG2 cells.ConclusionTreatment of hepatic cells with the herbo-vitamin medicine, Livogrit Vital, regulates IILI by modulation of oxidative and ER stress, apoptosis, and bioaccumulation of isoniazid and hydrazine. Collectively, Livogrit Vital could well be explored as an adjuvant hepatoprotective agent alongwith anti-TB medicines.

Unveiling Detoxifying Symbiosis and Dietary Influence on the Southern Green Shield Bug Microbiota.

The Southern green shield bug, Nezara viridula, is an invasive piercing and sucking pest insect that feeds on crops and poses a threat to global food production. Insects live in close relationships with microorganisms providing their host with unique capabilities, such as resistance to toxic plant metabolites. In this study, we investigated the resistance to and detoxification of the plant metabolite 3-nitropropionic acid by core and transient members of the N. viridula microbial community. Microbial community members showed a different tolerance to the toxin and we determined that six out of eight strains detoxified 3-nitropropionic acid. Additionally, we determined that 3-nitropropionic acid might interfere with the biosynthesis and transport of L-leucine. Moreover, our study explored the influence of diet on the gut microbial composition of N. viridula, demonstrating that switching to a single-plant diet shifts the abundance of core microbes. In line with this, testing pairwise microbial interactions revealed that core microbiota members support each other and repress the growth of transient microorganisms. With this work, we provide novel insights into the factors shaping the insect gut microbial communities and demonstrate that N. viridula harbours many toxin-degrading bacteria that could support its resistance to plant defences.

Comparison between mycobiota diversity and fungi and mycotoxin contamination of maize and wheat

Abstract The aim of this study was to establish the differences in fungi and mycotoxin contamination and mycobiota biodiversity between wheat and maize after harvesting. Determination of fungal contamination of wheat and maize is crucial, given that these grains are extensively used in food and feed production. Some moulds can produce toxic secondary metabolites, such as mycotoxins, which can cause serious health problems in humans and animals. Due to the metabolic activities of moulds, undesirable changes in food and feed colour, taste, and smell can occur. In this study, samples of wheat and maize, harvested during 2021 in the Northern Croatia, were analysed for mycological and mycotoxin contamination before storage. Also, potentially mycotoxigenic mould genera were identified at the species level in order to uncover the presence of toxigenic species. The presence of the following mycotoxins was examined: zearalenone, deoxynivalenol, ochratoxin, aflatoxin B1, T-2, and HT-2 toxin. The results indicate that both wheat and maize samples were contaminated with yeasts, with maize exhibiting a higher level of contamination as compared to wheat (1.5 × 104 to 1.8 × 106 vs 1.7 × 103 to 9.0 × 105). In wheat, the predominant mycotoxigenic mould species was Alternaria, as opposed to maize in which the Penicillium genus was the most represented. Mycotoxin analysis revealed that both maize and wheat were contaminated with Fusarium mycotoxins. Aflatoxin B1 and ochratoxin were not determined in any of the tested samples. The results point out that grains carry a different risk of contamination with Fusarium mycotoxins and that maize is more susceptible to fungus spoilage.