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INTRODUCTION: WNT1-inducible signalling pathway protein 1 (WISP1) promotes progression of several tumor entities often correlating with worse prognosis. Here its expression regulation and role in the progression of chronic liver diseases (CLD) was investigated. METHODS: WISP1 expression was analyzed in human HCC datasets, in biopsies and serum samples and an HCC patient tissue microarray (TMA) including correlation to clinicopathological parameters. Spatial distribution of WISP1 expression was determined using RNAscope analysis. Regulation of WISP1 expression was investigated in cytokine-stimulated primary mouse hepatocytes (PMH) by array analysis and qRT-PCR. Outcome of WISP1 stimulation was analyzed by IncuCyte S3-live cell imaging, qRT-PCR, and immunoblotting in murine AML12 cells. RESULTS: In a TMA, high WISP1 expression was positively correlated with early HCC stages and male sex. Highest WISP1 expression levels were detected in patients with cirrhosis as compared to healthy individuals, patients with early fibrosis, and non-cirrhotic HCC in liver biopsies, expression datasets and serum samples. WISP1 transcripts were predominantly detected in hepatocytes of cirrhotic rather than tumorous liver tissue. High WISP1 expression was associated with better survival. In PMH, AML12 and HepaRG, WISP1 was identified as a specific TGF-ß1 target gene. Accordingly, expression levels of both cytokines positively correlated in human HCC patient samples. WISP1-stimulation induced the expression of Bcl-xL, PCNA and p21 in AML12 cells. CONCLUSIONS: WISP1 expression is induced by TGF-ß1 in hepatocytes and is associated with cirrhotic liver disease. We propose a crucial role of WISP1 in balancing pro- and anti-tumorigenic effects during premalignant stages of CLD.
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BACKGROUND & AIMS: Metabolic dysfunction-associated steatotic liver disease (MASLD) is the most common cause of chronic liver disease. Its limited treatment options warrant novel pre-clinical models for target selection and drug validation. We have established and extensively characterized a primary human steatotic hepatocyte in vitro model system that could guide treatment strategies for MASLD. METHODS: Cryopreserved primary human hepatocytes from five donors varying in sex and ethnicity were cultured with free fatty acids (FFA) in 3D collagen sandwich for 7 days and the development of MASLD was followed by assessing classical hepatocellular functions. As proof of concept, the effects of the drug Firsocostat (GS-0976) on in vitro MASLD phenotypes were evaluated. RESULTS: Incubation with FFA induced steatosis, insulin resistance, mitochondrial dysfunction, inflammation, and alterations in prominent human gene signatures similar to patients with MASLD, indicating the recapitulation of human MASLD in this system. As the application of Firsocostat rescued clinically observed fatty liver disease pathologies, it highlights the ability of the in vitro system to test drug efficacy and potentially characterize their mode of action. CONCLUSIONS: Altogether, our human MASLD in vitro model system could guide the development and validation of novel targets and drugs for the treatment of MASLD. IMPACT AND IMPLICATIONS: Due to low drug efficacy and high toxicity, a clinical treatment option for MASLD is limited. To facilitate earlier stop-go decisions in drug development, we have established a primary human steatotic hepatocyte in vitro model. As the model recapitulates clinically relevant MASLD characteristics at high phenotypic resolution, it can serve as a pre-screening platform and guide target identification and validation in MASLD therapy.
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BACKGROUND & AIMS: Toll-like receptor 9 (Tlr9) is a pathogen recognition receptor detecting unmethylated DNA derivatives of pathogens and damaged host cells. It is therefore an important modulator of innate immunity. Here we investigated the role of Tlr9 in fibrogenesis and progression of hepatocellular carcinoma in chronic liver disease. MATERIALS AND METHODS: We treated mice with a constitutive deletion of Tlr9 (Tlr9-/-) with DEN/CCl4 for 24 weeks. As a second model, we used hepatocyte-specific Nemo knockout (NemoΔhepa) mice and generated double knockout (NemoΔhepaTlr9-/-) animals. RESULTS: We show that Tlr9 is in the liver primarily expressed in Kupffer cells, suggesting a key role of Tlr9 in intercellular communication during hepatic injury. Tlr9 deletion resulted in reduced liver fibrosis as well as tumor burden. We observed down-regulation of hepatic stellate cell activation and consequently decreased collagen production in both models. Tlr9 deletion was associated with decreased apoptosis and compensatory proliferation of hepatocytes, modulating the initiation and progression of hepatocarcinogenesis. These findings were accompanied by a decrease in interferon-ß and an increase in chemokines having an anti-tumoral effect. CONCLUSIONS: Our data define Tlr9 as an important receptor involved in fibrogenesis, but also in the initiation and progression of hepatocellular carcinoma during chronic liver diseases.
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Carcinoma Hepatocelular , Modelos Animales de Enfermedad , Neoplasias Hepáticas , Ratones Noqueados , Receptor Toll-Like 9 , Animales , Receptor Toll-Like 9/metabolismo , Receptor Toll-Like 9/genética , Carcinoma Hepatocelular/patología , Carcinoma Hepatocelular/metabolismo , Carcinoma Hepatocelular/genética , Ratones , Neoplasias Hepáticas/patología , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/genética , Cirrosis Hepática/patología , Cirrosis Hepática/metabolismo , Cirrosis Hepática/genética , Apoptosis , Ratones Endogámicos C57BL , Masculino , Macrófagos del Hígado/metabolismo , Macrófagos del Hígado/patología , Enfermedad Crónica , Células Estrelladas Hepáticas/metabolismo , Células Estrelladas Hepáticas/patología , Hepatocitos/metabolismo , Hepatocitos/patología , Péptidos y Proteínas de Señalización Intracelular/genética , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Proliferación Celular , Hepatopatías/patología , Hepatopatías/metabolismo , Hepatopatías/genética , Hígado/patología , Hígado/metabolismoRESUMEN
Ochratoxin A (OTA) is known to be strongly bound to serum albumin, but it remains unknown how albumin affects its metabolism and kinetics. To close this gap, we used a mouse model, where heterozygous albumin deletion reduces serum albumin to concentrations similar to hypoalbuminemic patients and completely eliminates albumin by a homozygous knockout. OTA and its potential metabolites (OTα, 4-OH-OTA, 7'-OH-OTA, OTHQ, OP-OTA, OTB-GSH, OTB-NAC, OTB) were time-dependently analyzed in plasma, bile, and urine by LC-MS/MS and were compared to previously published hepatotoxicity and nephrotoxicity data. Homozygous albumin deletion strongly accelerated plasma clearance as well as biliary and urinary excretion of the parent compound and its hydroxylation products. Decreasing albumin in mice by the heterozygous and even more by the homozygous knockout leads to an increase in the parent compound in urine which corresponded to increased nephrotoxicity. The role of albumin in OTA-induced hepatotoxicity is more complex, since heterozygous but not homozygous nor wild-type mice showed a strong biliary increase in the toxic open lactone OP-OTA. Correspondingly, OTA-induced hepatotoxicity was higher in heterozygous than in wild-type and homozygous animals. We present evidence that albumin-mediated retention of OTA in hepatocytes is required for formation of the toxic OP-OTA, while complete albumin elimination leads to rapid biliary clearance of OTA from hepatocytes with less formation of OP-OTA. In conclusion, albumin has a strong influence on metabolism and toxicity of OTA. In hypoalbuminemia, the parent OTA is associated with increased nephrotoxicity and the open lactone with increased hepatotoxicity.
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Albúminas , Ocratoxinas , Animales , Masculino , Ratones , Albúminas/metabolismo , Bilis/metabolismo , Cromatografía Liquida , Hígado/metabolismo , Hígado/efectos de los fármacos , Ratones Endogámicos C57BL , Ratones Noqueados , Ocratoxinas/metabolismo , Ocratoxinas/orina , Ocratoxinas/toxicidad , Albúmina Sérica/metabolismo , Espectrometría de Masas en TándemRESUMEN
Since 2006, the responsible regulatory bodies have proposed five health-based guidance values (HBGV) for bisphenol A (BPA) that differ by a factor of 250,000. This range of HBGVs covers a considerable part of the range from highly toxic to relatively non-toxic substances. As such heterogeneity of regulatory opinions is a challenge not only for scientific risk assessment but also for all stakeholders, the Senate Commission on Food Safety (SKLM) of the German Research Foundation (DFG) analyzed the reasons for the current discrepancy and used this example to suggest improvements for the process of HBGV recommendations. A key aspect for deriving a HBGV is the selection of appropriate studies that allow the identification of a point of departure (PoD) for risk assessment. In the case of BPA, the HBGV derived in the 2023 EFSA assessment was based on a study that reported an increase of Th17 cells in mice with a benchmark dose lower bound (BMDL40) of 0.53 µg/kg bw/day. However, this study does not comply with several criteria that are important for scientific risk assessment: (1) the selected end-point, Th17 cell frequency in the spleen of mice, is insufficiently understood with respect to health outcomes. (2) It is unclear, by which mechanism BPA may cause an increase in Th17 cell frequency. (3) It is unknown, if an increase of Th17 cell frequency in rodents is comparably observed in humans. (4) Toxicokinetics were not addressed. (5) Neither the raw data nor the experimental protocols are available. A further particularly important criterion (6) is independent data confirmation which is not available in the present case. Previous studies using other readouts did not observe immune-related adverse effects such as inflammation, even at doses orders of magnitude higher than in the Th17 cell-based study. The SKLM not only provides here key criteria for the use of such studies, but also suggests that the use of such a "checklist" requires a careful and comprehensive scientific judgement of each item. It is concluded that the Th17 cell-based study data do not represent an adequate basis for risk assessment of BPA.
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Compuestos de Bencidrilo , Fenoles , Compuestos de Bencidrilo/toxicidad , Fenoles/toxicidad , Medición de Riesgo/métodos , Animales , Humanos , Ratones , Relación Dosis-Respuesta a Droga , Guías como AsuntoRESUMEN
BACKGROUND: Despite progress understanding the mechanisms underlying tumor spread, metastasis remains a clinical challenge. We identified the choline-producing glycerophosphodiesterase, EDI3 and reported its association with metastasis-free survival in endometrial cancer. We also observed that silencing EDI3 slowed cell migration and other cancer-relevant phenotypes in vitro. Recent work demonstrated high EDI3 expression in ER-HER2+ breast cancer compared to the other molecular subtypes. Silencing EDI3 in ER-HER2+ cells significantly reduced cell survival in vitro and decreased tumor growth in vivo. However, a role for EDI3 in tumor metastasis in this breast cancer subtype was not explored. Therefore, in the present work we investigate whether silencing EDI3 in ER-HER2+ breast cancer cell lines alters phenotypes linked to metastasis in vitro, and metastasis formation in vivo using mouse models of experimental metastasis. METHODS: To inducibly silence EDI3, luciferase-expressing HCC1954 cells were transduced with lentiviral particles containing shRNA oligos targeting EDI3 under the control of doxycycline. The effect on cell migration, adhesion, colony formation and anoikis was determined in vitro, and significant findings were confirmed in a second ER-HER2+ cell line, SUM190PT. Doxycycline-induced HCC1954-luc shEDI3 cells were injected into the tail vein or peritoneum of immunodeficient mice to generate lung and peritoneal metastases, respectively and monitored using non-invasive bioluminescence imaging. Metabolite levels in cells and tumor tissue were analyzed using targeted mass spectrometry and MALDI mass spectrometry imaging (MALDI-MSI), respectively. RESULTS: Inducibly silencing EDI3 reduced cell adhesion and colony formation, as well as increased susceptibility to anoikis in HCC1954-luc cells, which was confirmed in SUM190PT cells. No influence on cell migration was observed. Reduced luminescence was seen in lungs and peritoneum of mice injected with cells expressing less EDI3 after tail vein and intraperitoneal injection, respectively, indicative of reduced metastasis. Importantly, mice injected with EDI3-silenced cells survived longer. Closer analysis of the peritoneal organs revealed that silencing EDI3 had no effect on metastatic organotropism but instead reduced metastatic burden. Finally, metabolic analyses revealed significant changes in choline and glycerophospholipid metabolites in cells and in pancreatic metastases in vivo. CONCLUSIONS: Reduced metastasis upon silencing supports EDI3's potential as a treatment target in metastasizing ER-HER2+ breast cancer.
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Neoplasias de la Mama , Receptor ErbB-2 , Receptores de Estrógenos , Animales , Femenino , Humanos , Ratones , Línea Celular Tumoral , Receptor ErbB-2/metabolismo , Receptor ErbB-2/genética , Neoplasias de la Mama/patología , Neoplasias de la Mama/genética , Neoplasias de la Mama/metabolismo , Receptores de Estrógenos/metabolismo , Modelos Animales de Enfermedad , Movimiento Celular , Técnicas de Silenciamiento del Gen , Carga Tumoral , Metástasis de la Neoplasia , Neoplasias Pulmonares/secundario , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/patología , Proliferación CelularRESUMEN
Dietary exposure to N-nitrosamines has recently been assessed by the European Food Safety Authority (EFSA) to result in margins of exposure that are conceived to indicate concern with respect to human health risk. However, evidence from more than half a century of international research shows that N-nitroso compounds (NOC) can also be formed endogenously. In this commentary of the Senate Commission on Food Safety (SKLM) of the German Research Foundation (DFG), the complex metabolic and physiological biokinetics network of nitrate, nitrite and reactive nitrogen species is discussed with emphasis on its influence on endogenous NOC formation. Pioneering approaches to monitor endogenous NOC have been based on steady-state levels of N-nitrosodimethylamine (NDMA) in human blood and on DNA adduct levels in blood cells. Further NOC have not been considered yet to a comparable extent, although their generation from endogenous or exogenous precursors is to be expected. The evidence available to date indicates that endogenous NDMA exposure could exceed dietary exposure by about 2-3 orders of magnitude. These findings require consolidation by refined toxicokinetics and DNA adduct monitoring data to achieve a credible and comprehensive human health risk assessment.
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Aductos de ADN , Exposición Dietética , Dimetilnitrosamina , Nitrosaminas , Humanos , Medición de Riesgo , Nitrosaminas/toxicidad , Nitrosaminas/farmacocinética , Exposición Dietética/efectos adversos , Dimetilnitrosamina/toxicidad , Contaminación de Alimentos , Inocuidad de los Alimentos , Animales , Nitritos/toxicidad , Nitratos/toxicidad , Nitratos/farmacocinética , Especies de Nitrógeno Reactivo/metabolismoRESUMEN
Acetaminophen (APAP) is known to cause a breach of the blood-bile barrier in mice that, via a mechanism called futile bile acid (BA) cycling, increases BA concentrations in hepatocytes above cytotoxic thresholds. Here, we compared this mechanism in mice and rats, because both species differ massively in their susceptibility to APAP and compared the results to available human data. Dose and time-dependent APAP experiments were performed in male C57BL6/N mice and Wistar rats. The time course of BA concentrations in liver tissue and in blood was analyzed by MALDI-MSI and LC-MS/MS. APAP and its derivatives were measured in the blood by LC-MS. APAP-induced liver damage was analyzed by histopathology, immunohistochemistry, and by clinical chemistry. In mice, a transient increase of BA in blood and in peri-central hepatocytes preceded hepatocyte death. The BA increase coincided with oxidative stress in liver tissue and a compromised morphology of bile canaliculi and immunohistochemically visualized tight junction proteins. Rats showed a reduced metabolic activation of APAP compared to mice. However, even at very high doses that caused cell death of hepatocytes, no increase of BA concentrations was observed neither in liver tissue nor in the blood. Correspondingly, no oxidative stress was detectable, and the morphology of bile canaliculi and tight junction proteins remained unaltered. In conclusion, different mechanisms cause cell death in rats and mice, whereby oxidative stress and a breach of the blood-bile barrier are seen only in mice. Since transient cholestasis also occurs in human patients with APAP overdose, mice are a clinically relevant species to study APAP hepatotoxicity but not rats.
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Acetaminofén , Enfermedad Hepática Inducida por Sustancias y Drogas , Ratones , Ratas , Humanos , Masculino , Animales , Acetaminofén/toxicidad , Acetaminofén/metabolismo , Bilis/metabolismo , Cromatografía Liquida , Enfermedad Hepática Inducida por Sustancias y Drogas/patología , Ratas Wistar , Espectrometría de Masas en Tándem , Hígado/metabolismo , Hepatocitos/metabolismo , Ratones Endogámicos C57BL , Proteínas de Uniones Estrechas/metabolismoRESUMEN
Large interspecies differences between rats and mice concerning the hepatotoxicity and carcinogenicity of aflatoxin B1 (AFB1) are known, with mice being more resistant. However, a comprehensive interspecies comparison including subcellular liver tissue compartments has not yet been performed. In this study, we performed spatio-temporal intravital analysis of AFB1 kinetics in the livers of anesthetized mice and rats. This was supported by time-dependent analysis of the parent compound as well as metabolites and adducts in blood, urine, and bile of both species by HPLC-MS/MS. The integrated data from intravital imaging and HPLC-MS/MS analysis revealed major interspecies differences between rats and mice: (1) AFB1-associated fluorescence persisted much longer in the nuclei of rat than mouse hepatocytes; (2) in the sinusoidal blood, AFB1-associated fluorescence was rapidly cleared in mice, while a time-dependent increase was observed in rats in the first three hours after injection followed by a plateau that lasted until the end of the observation period of six hours; (3) this coincided with a far stronger increase of AFB1-lysine adducts in the blood of rats compared to mice; (4) the AFB1-guanine adduct was detected at much higher concentrations in bile and urine of rats than mice. In both species, the AFB1-glutathione conjugate was efficiently excreted via bile, where it reached concentrations at least three orders of magnitude higher compared to blood. In conclusion, major differences between mice and rats were observed, concerning the nuclear persistence, formation of AFB1-lysine adducts, and the AFB1-guanine adducts.
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Aflatoxinas , Ratas , Ratones , Animales , Aflatoxinas/metabolismo , Aflatoxinas/toxicidad , Lisina/metabolismo , Cromatografía Líquida con Espectrometría de Masas , Espectrometría de Masas en Tándem , Hígado/metabolismo , Aflatoxina B1/toxicidad , Guanina/metabolismo , Microscopía IntravitalRESUMEN
While several studies have shown associations between hearing disorders and congenital toxoplasmosis, the present study investigated the impact of chronic, latent Toxoplasma gondii (T. gondii) infection on hearing loss. We used a regression analysis to explore whether latent T. gondii infection modulates changes in hearing thresholds over an age range from 20 to 70 years. We analyzed audiometric data of 162 T. gondii IgG-positive and 430 T. gondii-negative participants, collected in the Dortmund Vital Study (DVS, ClinicalTrials.gov Identifier: NCT05155397), a prospective study on healthy cognitive aging. The regression analysis indicated that latent toxoplasmosis was associated with an accelerated development in hearing loss over the observed age range. Hearing loss was less frequent in IgG-positive than in IgG-negative participants up to the age of about 40 for a low (0.125-1 kHz)-frequency range. For high (2-8 kHz) frequencies, this pattern reversed for ages above 65 years. We discuss these findings on hearing function in the context of a recently proposed model, suggesting that latent toxoplasmosis can differentially affect brain functions across a lifespan.
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Chronic liver diseases are worldwide on the rise. Due to the rapidly increasing incidence, in particular in Western countries, metabolic dysfunction-associated steatotic liver disease (MASLD) is gaining importance as the disease can develop into hepatocellular carcinoma. Lipid accumulation in hepatocytes has been identified as the characteristic structural change in MASLD development, but molecular mechanisms responsible for disease progression remained unresolved. Here, we uncover in primary hepatocytes from a preclinical model fed with a Western diet (WD) an increased basal MET phosphorylation and a strong downregulation of the PI3K-AKT pathway. Dynamic pathway modeling of hepatocyte growth factor (HGF) signal transduction combined with global proteomics identifies that an elevated basal MET phosphorylation rate is the main driver of altered signaling leading to increased proliferation of WD-hepatocytes. Model-adaptation to patient-derived hepatocytes reveal patient-specific variability in basal MET phosphorylation, which correlates with patient outcome after liver surgery. Thus, dysregulated basal MET phosphorylation could be an indicator for the health status of the liver and thereby inform on the risk of a patient to suffer from liver failure after surgery.
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Carcinoma Hepatocelular , Hígado Graso , Neoplasias Hepáticas , Humanos , Fosforilación , Fosfatidilinositol 3-Quinasas/metabolismo , Hepatocitos/metabolismo , Factor de Crecimiento de Hepatocito/metabolismo , Hígado Graso/metabolismo , Neoplasias Hepáticas/patologíaRESUMEN
Even though the number of studies aiming to improve comprehension of ADHD pathology has increased in recent years, there still is an urgent need for more effective studies, particularly in understanding adult ADHD, both at preclinical and clinical levels, due to the increasing evidence that adult ADHD is highly distinct and a different entity from childhood ADHD. This review paper outlines the symptoms, diagnostics, and neurobiological mechanisms of ADHD, with emphasis on how adult ADHD could be different from childhood-onset. Data show a difference in the environmental, genetic, epigenetic, and brain structural changes, when combined, could greatly impact the behavioral presentations and the severity of ADHD in adults. Furthermore, a crucial aspect in the quest to fully understand this disorder could be through longitudinal analysis. In this way, we will determine if and how the pathology and pharmacology of ADHD change with age. This goal could revolutionize our understanding of the disorder and address the weaknesses in the current clinical classification systems, improving the characterization and validity of ADHD diagnosis, specifically those in adults.
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Trastorno por Déficit de Atención con Hiperactividad , Adulto , Humanos , Niño , Trastorno por Déficit de Atención con Hiperactividad/diagnóstico , Trastorno por Déficit de Atención con Hiperactividad/patología , Encéfalo/patología , MotivaciónRESUMEN
Rationale: Liver cirrhosis is known to affect drug pharmacokinetics, but the functional assessment of the underlying pathophysiological alterations in drug metabolism is difficult. Methods: Cirrhosis in mice was induced by repeated treatment with carbon tetrachloride for 12 months. A cocktail of six drugs was administered, and parent compounds as well as phase I and II metabolites were quantified in blood, bile, and urine in a time-dependent manner. Pharmacokinetics were modeled in relation to the altered expression of metabolizing enzymes. In discrepancy with computational predictions, a strong increase of glucuronides in blood was observed in cirrhotic mice compared to vehicle controls. Results: The deviation between experimental findings and computational simulations observed by analyzing different hypotheses could be explained by increased sinusoidal export and corresponded to increased expression of export carriers (Abcc3 and Abcc4). Formation of phase I metabolites and clearance of the parent compounds were surprisingly robust in cirrhosis, although the phase I enzymes critical for the metabolism of the administered drugs in healthy mice, Cyp1a2 and Cyp2c29, were downregulated in cirrhotic livers. RNA-sequencing revealed the upregulation of numerous other phase I metabolizing enzymes which may compensate for the lost CYP isoenzymes. Comparison of genome-wide data of cirrhotic mouse and human liver tissue revealed similar features of expression changes, including increased sinusoidal export and reduced uptake carriers. Conclusion: Liver cirrhosis leads to increased blood concentrations of glucuronides because of increased export from hepatocytes into the sinusoidal blood. Although individual metabolic pathways are massively altered in cirrhosis, the overall clearance of the parent compounds was relatively robust due to compensatory mechanisms.
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Aflatoxin B1 (AFB1) is a highly hepatotoxic and carcinogenic mycotoxin produced by Aspergillus species. The compound is mainly metabolized in the liver and its metabolism varies between species. The present study quantified relevant AFB1- metabolites formed by mouse, rat, and human primary hepatocytes after treatment with 1 µM and 10 µM AFB1. The use of liquid chromatographic separation coupled with tandem mass spectrometric detection enabled the selective and sensitive determination of phase I and phase II metabolites of AFB1 over incubation times of up to 24 h. The binding of AFB1 to macromolecules was also considered. The fastest metabolism of AFB1 was observed in mouse hepatocytes which formed aflatoxin P1 as a major metabolite and also its glucuronidated form, while AFP1 occurred only in traces in the other species. Aflatoxin M1 was formed in all species and was, together with aflatoxin Q1 and aflatoxicol, the main metabolite in human cells. Effective epoxidation led to high amounts of DNA adducts already 30 min post-treatment, especially in rat hepatocytes. Lower levels of DNA adducts and fast DNA repair were found in mouse hepatocytes. Also, protein adducts arising from reactive intermediates were formed rapidly in all three species. Detoxification via glutathione conjugation and subsequent formation of the N-acetylcysteine derivative appeared to be similar in mice and in rats and strongly differed from human hepatocytes which did not form these metabolites at all. The use of qualitative reference material of a multitude of metabolites and the comparison of hepatocyte metabolism in three species using advanced methods enabled considerations on toxification and detoxification mechanisms of AFB1. In addition to glutathione conjugation, phase I metabolism is strongly involved in the detoxification of AFB1.
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Aflatoxina B1 , Aflatoxinas , Humanos , Ratas , Ratones , Animales , Aflatoxina B1/toxicidad , Cromatografía Líquida de Alta Presión , Aductos de ADN/metabolismo , Espectrometría de Masas en Tándem , ADN , Aflatoxinas/farmacología , Aflatoxinas/toxicidad , Hígado , Hepatocitos/metabolismo , Glutatión/metabolismoRESUMEN
PFASs are defined as substances that contain at least one fully fluorinated methyl (CF3-) or methylene (-CF2-) carbon atom. The excellent technical properties of members of the PFAS group have led to their use in a wide range of applications. The substance group comprises more than 10,000 individual compounds. A variety of adverse effects has been described for single substances. For the majority of the PFASs, neither toxicokinetic data nor effect data is available. Hence, because of the small number of PFASs for which a full toxicological profile is available, grouping based on the existing data is not feasible. A critical problem of PFASs and their degradation products is the very high persistence, which clearly fulfils the criterion for the substance property Very Persistent (vP) according to Annex XIII of the REACH Regulation. Because of this property the European Commission is planning to take action. Defining suitable subgroups appears to be a scientifically based approach. However, to reach this goal, large data gaps would have to be closed which would take up to centuries, a time-frame, which is not defendable with respect to potential irreversible harm. Because of the time pressure resulting from the potential irreversible harm, the precautionary principle has been selected as an appropriate tool to handle PFASs and in the restriction proposal PFASs are treated as one group. This approach is justified in the view of the advisory committee of the German Society for Toxicology. ECHA's proposal received a lot of attention in the public. However, communication so far has obviously led to the misunderstanding of a proven health hazard for all PFASs. Communication should explain the justification of the broad inclusion of substances as being based on the precautionary principle. Data gaps versus current knowledge need to be clearly communicated; communication should also include the possibility for derogation of essential use. It should address the issue of suitable substitutes to avoid unintended health consequences; and it should mention that existing persistent environmental contamination calls for developing innovation in remediation techniques.
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Fluorocarburos , Contaminantes Químicos del Agua , Fluorocarburos/toxicidad , Contaminación AmbientalRESUMEN
The Senate Commission on Food Safety (SKLM) of the German Research Foundation (DFG) has reviewed the currently available data in order to assess the health risks associated with the use of acetaldehyde as a flavoring substance in foods. Acetaldehyde is genotoxic in vitro. Following oral intake of ethanol or inhalation exposure to acetaldehyde, systemic genotoxic effects of acetaldehyde in vivo cannot be ruled out (induction of DNA adducts and micronuclei). At present, the key question of whether acetaldehyde is genotoxic and mutagenic in vivo after oral exposure cannot be answered conclusively. There is also insufficient data on human exposure. Consequently, it is currently not possible to reliably assess the health risk associated with the use of acetaldehyde as a flavoring substance. However, considering the genotoxic potential of acetaldehyde as well as numerous data gaps that need to be filled to allow a comprehensive risk assessment, the SKLM considers that the use of acetaldehyde as a flavoring may pose a safety concern. For reasons of precautionary consumer protection, the SKLM recommends that the scientific base for approval of the intentional addition of acetaldehyde to foods as a flavoring substance should be reassessed.
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Acetaldehído , Aditivos Alimentarios , Humanos , Acetaldehído/toxicidad , Medición de Riesgo , AlimentosRESUMEN
Metabolic Dysfunction Associated Steatotic Liver Disease (MASLD) is the most common chronic liver disease in Western countries. It is becoming increasingly evident that peripheral organ-centered inflammatory diseases, including liver diseases, are linked with brain dysfunctions. Therefore, this study aims to unravel the effect of MASLD on brain histology, cognitive functions, and neurotransmitters. For this purpose, mice fed for 48 weeks on standard (SD) or Western diet (WD) were evaluated by behavioral tests, followed by sacrifice and analysis of the liver-brain axis including histopathology, immunohistochemistry, and biochemical analyses. Histological analysis of the liver showed features of Metabolic Dysfunction-Associated Steatohepatitis (MASH) in the WD-fed mice including lipid droplet accumulation, inflammation, and fibrosis. This was accompanied by an elevation of transaminase and alkaline phosphatase activities, increase in inflammatory cytokine and bile acid concentrations, as well as altered amino acid concentrations in the blood. Interestingly, compromised blood capillary morphology coupled with astrogliosis and microgliosis were observed in brain hippocampus of the WD mice, indicating neuroinflammation or a disrupted neurovascular unit. Moreover, attention was impaired in WD-fed mice along with the observations of impaired motor activity and balance, enhanced anxiety, and stereotyped head-twitch response (HTR) behaviors. Analysis of neurotransmitters and modulators including dopamine, serotonin, GABA, glutamate, and acetylcholine showed region-specific dysregulation in the brain of the WD-fed mice. In conclusion, the induction of MASH in mice is accompanied by the alteration of cellular morphology and neurotransmitter expression in the brain, associated with compromised cognitive functions.
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Dieta Occidental , Hígado Graso , Animales , Ratones , Dieta Occidental/efectos adversos , Cognición , EncéfaloRESUMEN
Urinary bladder cancer, a smoking and occupation related disease, was subject of several genome-wide association studies (GWAS). However, studies on the course of the disease based on GWAS findings differentiating between muscle invasive bladder cancer (MIBC) and non-muscle invasive bladder cancer (NMIBC) are rare. Thus we investigated 4 single nucleotide polymorphisms (SNPs) detected in GWAS, related to the genes coding for TACC3 (transforming, acidic coiled-coil containing protein 3), for FGFR3 (fibroblast growth factor receptor 3), for PSCA (prostate stem cell antigen) and the genes coding for CBX6 (chromobox homolog 6) and APOBEC3A (apolipoprotein B mRNA editing enzyme, catalytic polypeptide-like 3A). This study is based on 712 bladder cancer patients and 875 controls from 3 different case control studies in Germany. The 4 SNPs of interest (PSCA rs2294008 and rs2978974, FGFR3-TACC3 rs798766, and CBX6-APOBEC3A rs1014971) were determined by real-time polymerase chain reaction. The distribution of the 4 SNPs does not vary significantly between cases and controls in the entire study group and in the 3 local subgroups, including two former highly industrialized areas and a region without such history. Also, no significant differences in the bladder cancer subgroups of MIBC and NMIBC were observed. The 4 investigated SNPs do not noticeably contribute differently to the bladder cancer risk for the bladder cancer subgroups of MIBC and NMIBC.
RESUMEN
Parabens have been used for decades as preservatives in food, drugs and cosmetics. The majority however, were banned in 2009 and 2014 leaving only methyl-, ethyl-, propyl-, and butyl-derivates available for subsequent use. Methyl- and propylparaben have been extensively tested in vivo, with no resulting evidence for developmental and reproductive toxicity (DART). In contrast, ethylparaben has not yet been tested for DART in animal experiments, and it is currently debated if additional animal studies are warranted. In order to perform a comparison of the four currently approved parabens, we used a previously established in vitro test based on human induced pluripotent stem cells (iPSC) that are exposed to test substances during their differentiation to neuroectodermal cells. EC50 values for cytotoxicity were 906 µM, 698 µM, 216 µM and 63 µM for methyl-, ethyl-, propyl- and butylparaben, respectively, demonstrating that cytotoxicity increases with increasing alkyl chain length. Genome-wide analysis demonstrated that FDR-adjusted significant gene expression changes occurred only at cytotoxic or close to cytotoxic concentrations, for example 1720 differentially expressed genes (DEG) at 1000 µM ethylparaben, 1 DEG at 316 µM, and no DEG at 100 µM or lower concentrations. The highest concentration of ethylparaben that did not induce any cytotoxicity nor DEG was 1670-fold above the highest concentration reported in biomonitoring studies (60 nM ethylparaben in cord blood). In conclusion, cytotoxicity and gene expression alterations of ethylparaben occurred at concentrations of approximately three orders of magnitude above human blood concentrations; moreover, the substance fitted well into a scenario where toxicity increases with the alkyl chain length, and gene expression changes only occur at cytotoxic or close to cytotoxic concentrations. Therefore, no evidence was obtained suggesting that in vivo DART with ethylparaben would lead to different results as the methyl- or propyl derivates.