Molecular signatures of angiogenesis inhibitors: a single-embryo untargeted metabolomics approach in zebrafish

Angiogenesis is a key process in embryonic development, a disruption of this process can lead to severe developmental defects, such as limb malformations. The identification of molecular perturbations representative of antiangiogenesis in zebrafish embryo (ZFE) may guide the assessment of developmental toxicity from an endpoint- to a mechanism-based approach, thereby improving the extrapolation of findings to humans. Thus, the aim of the study was to discover molecular changes characteristic of antiangiogenesis and developmental toxicity. We exposed ZFEs to two antiangiogenic drugs (SU4312, sorafenib) and two developmental toxicants (methotrexate, rotenone) with putative antiangiogenic action. Molecular changes were measured by performing untargeted metabolomics in single embryos. The metabolome response was accompanied by the occurrence of morphological alterations. Two distinct metabolic effect patterns were observed. The first pattern comprised common effects of two specific angiogenesis inhibitors and the known teratogen methotrexate, strongly suggesting a shared mode of action of antiangiogenesis and developmental toxicity. The second pattern involved joint effects of methotrexate and rotenone, likely related to disturbances in energy metabolism. The metabolites of the first pattern, such as phosphatidylserines, pterines, retinol, or coenzyme Q precursors, represented potential links to antiangiogenesis and related developmental toxicity. The metabolic effect pattern can contribute to biomarker identification for a mechanism-based toxicological testing.

Developmental neurotoxicity evaluation of three Chinese herbal medicines in zebrafish larvae by means of two behavioral assays: Touch-evoked response and light/dark transition

Chinese herbal medicine (CHM) is used among pregnant women. However, the question of its safety during pregnancy remains unclear. The use of these products relies on history of use data but there are specific toxicities like developmental neurotoxicity that are clearly understudied. Here we use the zebfrafish embryo developmental toxicity assay (ZEDTA) in combination with two behavioral assays: touch-evoked response and Light/Dark (L/D) transition assay to evaluate the neuro/developmental toxicity of three herbal products commonly used in CHM [Chinese name (abbreviation; part of the plant and Scientific name]: tian ma (TM; tuber form Gastrodia elata Blume), lei gong teng (LGT; root and rhizome of Tripterygium wilfordii Hook.f) and cha ye (green tea, leaves from Camellia sinensis (L.) Kuntze). In case significant alterations were detected, single components with potential exposure during pregnancy were identified in the literature and further tested. TM had no neurodevelopmental toxic potential in zebrafish embryos, while LGT and its main compounds triptolide and celastrol induced significant alterations in behavior. Developmental exposure to EGCG, the main catechin of green tea, also produced significant alterations in zebrafish embryos behavior after developmental exposure. A combination of ZEDTA with L/D Transition assay is proposed as a useful combination of alternative methods for DNT assessment of CHM products together with other New Approach Methodologies (NAMs).

First-Generation Synthetic Cathinones Produce Arrhythmia in Zebrafish Eleutheroembryos: A New Approach Methodology for New Psychoactive Substances Cardiotoxicity Evaluation

The increasing number of new psychoactive substances (NPS) entering the illicit drug market, especially synthetic cathinones, as well as the risk of cardiovascular complications, is intensifying the need to quickly assess their cardiotoxic potential. The present study aims to evaluate the cardiovascular toxicity and lethality induced by first-generation synthetic cathinones (mephedrone, methylone, and MDPV) and more classical psychostimulants (cocaine and MDMA) in zebrafish embryos using a new approach methodology (NAM). Zebrafish embryos at 4 dpf were exposed to the test drugs for 24 h to identify drug lethality. Drug-induced effects on ventricular and atrial heart rate after 2 h exposure were evaluated, and video recordings were properly analyzed. All illicit drugs displayed similar 24 h LC50 values. Our results indicate that all drugs are able to induce bradycardia, arrhythmia, and atrial-ventricular block (AV block), signs of QT interval prolongation. However, only MDPV induced a different rhythmicity change depending on the chamber and was the most potent bradycardia and AV block-inducing drug compared to the other tested compounds. In summary, our results strongly suggest that the NAM presented in this study can be used for screening NPS for their cardiotoxic effect and especially for their ability to prolong the QT intervals.

A metabolomics approach to reveal the mechanism of developmental toxicity in zebrafish embryos exposed to 6-propyl-2-thiouracil

A crucial component of a substance registration and regulation is the evaluation of human prenatal developmental toxicity. Current toxicological tests are based on mammalian models, but these are costly, time consuming and may pose ethical concerns. The zebrafish embryo has evolved as a promising alternative model to study developmental toxicity. However, the implementation of the zebrafish embryotoxicity test is challenged by lacking information on the relevance of observed morphological alterations in fish for human developmental toxicity. Elucidating the mechanism of toxicity could help to overcome this limitation. Through LC-MS/MS and GC-MS metabolomics, we investigated whether changes to the endogenous metabolites can indicate pathways associated with developmental toxicity. To this aim, zebrafish embryos were exposed to different concentrations of 6-propyl-2-thiouracil (PTU), a compound known to induce developmental toxicity. The reproducibility and the concentration-dependence of the metabolome response and its association with morphological alterations were studied. Major morphological findings were reduced eye size, and other craniofacial anomalies; major metabolic changes included increased tyrosine, pipecolic acid and lysophosphatidylcholine levels, decreased methionine levels, and disturbance of the 'Phenylalanine, tyrosine and tryptophan biosynthesis' pathway. This pathway, and the changes in tyrosine and pipecolic acid levels could be linked to the mode of action of PTU, i.e., inhibition of thyroid peroxidase (TPO). The other findings suggested neurodevelopmental impairments. This proof-of-concept study demonstrated that metabolite changes in zebrafish embryos are robust and provide mechanistic information associated with the mode of action of PTU.

Lactoferrin/sialic acid prevents adverse effects of intrauterine growth restriction on neurite length: investigations in an in vitro rabbit neurosphere model

Introduction

Intrauterine growth restriction (IUGR) is a well-known cause of impaired neurodevelopment during life. In this study, we aimed to characterize alterations in neuronal development underlying IUGR and discover strategies to ameliorate adverse neurodevelopment effects by using a recently established rabbit in vitro neurosphere culture.

Methods

IUGR was surgically induced in pregnant rabbits by ligation of placental vessels in one uterine horn, while the contralateral horn remained unaffected for normal growth (control). At this time point, rabbits were randomly assigned to receive either no treatment, docosahexaenoic acid (DHA), melatonin (MEL), or lactoferrin (LF) until c-section. Neurospheres consisting of neural progenitor cells were obtained from control and IUGR pup's whole brain and comparatively analyzed for the ability to differentiate into neurons, extend neurite length, and form dendritic branching or pre-synapses. We established for the very first time a protocol to cultivate control and IUGR rabbit neurospheres not only for 5 days but under long-term conditions up to 14 days under differentiation conditions. Additionally, an in vitro evaluation of these therapies was evaluated by exposing neurospheres from non-treated rabbits to DHA, MEL, and SA (sialic acid, which is the major lactoferrin compound) and by assessing the ability to differentiate neurons, extend neurite length, and form dendritic branching or pre-synapses.

Results

We revealed that IUGR significantly increased the neurite length after 5 days of cultivation in vitro, a result in good agreement with previous in vivo findings in IUGR rabbits presenting more complex dendritic arborization of neurons in the frontal cortex. MEL, DHA, and SA decreased the IUGR-induced length of primary dendrites in vitro, however, only SA was able to reduce the total neurite length to control level in IUGR neurospheres. After prenatal in vivo administration of SAs parent compound LF with subsequent evaluation in vitro, LF was able to prevent abnormal neurite extension.

Discussion

We established for the first time the maintenance of the rabbit neurosphere culture for 14 days under differentiation conditions with increasing complexity of neuronal length and branching up to pre-synaptic formation. From the therapies tested, LF or its major compound, SA, prevents abnormal neurite extension and was therefore identified as the most promising therapy against IUGR-induced changes in neuronal development.

Cobalt chloride has beneficial effects across species through a hormetic mechanism

Severe oxygen and iron deficiencies have evolutionarily conserved detrimental effects, leading to pathologies in mammals and developmental arrest as well as neuromuscular degeneration in the nematode Caenorhabditis elegans. Yet, similar to the beneficial effects of mild hypoxia, non-toxic levels of iron depletion, achieved with the iron chelator bipyridine or through frataxin silencing, extend C. elegans lifespan through hypoxia-like induction of mitophagy. While the positive health outcomes of hypoxia preconditioning are evident, its practical application is rather challenging. Here, we thus test the potential beneficial effects of non-toxic, preconditioning interventions acting on iron instead of oxygen availability. We find that limiting iron availability through the iron competing agent cobalt chloride has evolutionarily conserved dose-dependent beneficial effects: while high doses of cobalt chloride have toxic effects in mammalian cells, iPS-derived neurospheres, and in C. elegans, sub-lethal doses protect against hypoxia- or cobalt chloride-induced death in mammalian cells and extend lifespan and delay age-associated neuromuscular alterations in C. elegans. The beneficial effects of cobalt chloride are accompanied by the activation of protective mitochondrial stress response pathways.

Protocols for the Evaluation of Neurodevelopmental Alterations in Rabbit Models In Vitro and In Vivo

The rabbit model is gaining importance in the field of neurodevelopmental evaluation due to its higher similarity to humans in terms of brain development and maturation than rodents. In this publication, we detailed 14 protocols covering toxicological relevant endpoints for the assessment of neurodevelopmental adverse effects in the rabbit species. These protocols include both in vitro and in vivo techniques, which also cover different evaluation time-points, the neonatal period, and long-term examinations at postnatal days (PNDs) 50–70. Specifically, the protocols (P) included are as follows: neurosphere preparation (GD30/PND0; P2) and neurosphere assay (P3), behavioral ontogeny (PND1; P4), brain obtaining and brain weight measurement at two different ages: PND1 (P5) and PND70 (P12), neurohistopathological evaluations after immersion fixation for neurons, astrocytes, oligodendrocytes and microglia (PND1; P6-9) or perfusion fixation (PND70; P12), motor activity (P11, open field), memory and sensory function (P11, object recognition test), learning (P10, Skinner box), and histological evaluation of plasticity (P13 and P14) through dendritic spines and perineuronal nets. The expected control values and their variabilities are presented together with the information on how to troubleshoot the most common issues related to each protocol. To sum up, this publication offers a comprehensive compilation of reliable protocols adapted to the rabbit model for neurodevelopmental assessment in toxicology.

Developmental exposure to MDMA (ecstasy) in zebrafish embryos reproduces the neurotoxicity adverse outcome 'lower motor activity' described in humans

The recreational use of MDMA (ecstasy) by pregnant women is associated with impaired neuromotor function in infants, but the Adverse Outcome Pathway behind this effect is not clear yet. We present for the first time the evaluation of developmental neurotoxic (DNT) effects of MDMA in zebrafish embryos. The aim of the study was to determine whether the zebrafish model reproduces the adverse outcome occurring in humans. We have studied the DNT effects of MDMA in zebrafish within a range of 5-250 μM performing different behavioural tests: spontaneous tail-coiling and light-dark locomotor response; after exposing the embryos to 4 different scenarios combining changes in pH, in starting exposure time and exposure duration. In these scenarios we evaluated the effects of MDMA in general embryonic development and compared the concentrations producing them with those inducing specific DNT effects. As a result, we have established the experimental conditions leading to the adverse outcome "lower motor activity" in zebrafish without producing general developmental delay or general toxicity. The experimental condition chosen opens the door to use this model in future mechanistic investigations to better characterize the Adverse Outcome Pathway associated with the adverse effects caused by MDMA prenatal exposure in humans.

Structural Brain Changes during the Neonatal Period in a Rabbit Model of Intrauterine Growth Restriction

BACKGROUND

Intrauterine growth restriction (IUGR) is associated with abnormal neurodevelopment, but the associated structural brain changes are poorly documented. The aim of this study was to describe in an animal model the brain changes at the cellular level in the gray and white matter induced by IUGR during the neonatal period.

METHODS

The IUGR model was surgically induced in pregnant rabbits by ligating 40-50% of the uteroplacental vessels in 1 horn, whereas the uteroplacental vessels of the contralateral horn were not ligated. After 5 days, IUGR animals from the ligated horn and controls from the nonligated were delivered. On the day of delivery, perinatal data and placentas were collected. On postnatal day 1, functional changes were first evaluated, and thereafter, neuronal arborization in the frontal cortex and density of pre-oligodendrocytes, astrocytes, and microglia in the corpus callosum were evaluated.

RESULTS

Higher stillbirth in IUGR fetuses together with a reduced birth weight as compared to controls was evidenced. IUGR animals showed poorer functional results, an altered neuronal arborization pattern, and a decrease in the pre-oligodendrocytes, with no differences in microglia and astrocyte densities.

CONCLUSIONS

Overall, in the rabbit model used, IUGR is related to functional and brain changes evidenced already at birth, including changes in the neuronal arborization and abnormal oligodendrocyte maturation.

Epigallocatechin-3-gallate PEGylated poly(lactic-co-glycolic) acid nanoparticles mitigate striatal pathology and motor deficits in 3-nitropropionic acid intoxicated mice

Aim: To compare free and nanoparticle (NP)-encapsulated epigallocatechin-3-gallate (EGCG) for the treatment of Huntington's disease (HD)-like symptoms in mice. Materials & methods: EGCG was incorporated into PEGylated poly(lactic-co-glycolic) acid NPs with ascorbic acid (AA). HD-like striatal lesions and motor deficit were induced in mice by 3-nitropropionic acid-intoxication. EGCG and EGCG/AA NPs were co-administered and behavioral motor assessments and striatal histology performed after 5 days. Results: EGCG/AA NPs were significantly more effective than free EGCG in reducing motor disturbances and depression-like behavior associated with 3-nitropropionic acid toxicity. EGCG/AA NPs treatment also mitigated neuroinflammation and prevented neuronal loss. Conclusion: NP encapsulation enhances therapeutic robustness of EGCG in this model of HD symptomatology. Together with our previous findings, this highlights the potential of EGCG/AA NPs in the symptomatic treatment of neurodegenerative diseases.

Rabbit neurospheres as a novel in vitro tool for studying neurodevelopmental effects induced by intrauterine growth restriction

The aim of this study was to develop a rabbit neurosphere culture to characterize differences in basic processes of neurogenesis induced by intrauterine growth restriction (IUGR). A novel in vitro neurosphere culture has been established using fresh or frozen neural progenitor cells from newborn (PND0) rabbit brains. After surgical IUGR induction in pregnant rabbits and cesarean section 5 days later, neural progenitor cells from both control and IUGR groups were isolated and directly cultured or frozen at −80°C. These neural progenitor cells spontaneously formed neurospheres after 7 days in culture. The ability of control and IUGR neurospheres to migrate, proliferate, differentiate to neurons, astrocytes, or oligodendrocytes was compared and the possibility to modulate their responses was tested by exposure to several positive and negative controls. Neurospheres obtained from IUGR brains have a significant impairment in oligodendrocyte differentiation, whereas no significant differences are observed in other basic processes of neurogenesis. This impairment can be reverted by in vitro exposure of IUGR neurospheres to thyroid hormone, which is known to play an essential role in white matter maturation in vivo. Our new rabbit neurosphere model and the results of this study open the possibility to test several substances in vitro as neuroprotective candidates against IUGR induced neurodevelopmental damage while decreasing the number of animals and resources and allowing a more mechanistic approach at a cellular functional level.

Developmental neurotoxicity of MDMA. A systematic literature review summarized in a putative adverse outcome pathway

The increasing use of illegal drugs by pregnant women causes a public health concern because it is associated with health risks for mothers and their developing children. One of such drugs is MDMA (3,4-methylenedioxymethamphetamine) or ecstasy due to its high consumption in relevant age and sex groups and its adverse effects on human and rodent developing brains. To thoroughly review the current knowledge on the developmentally neurotoxic potential of MDMA we systematically collected and summarized articles investigating developmental neurotoxicity (DNT) of MDMA in humans and animals in vivo and in vitro. In addition, we summarized the findings in a putative adverse outcome pathway (AOP). From an initial 299 articles retrieved from the bibliographic databases Web of Science, PubMed and DART, we selected 39 articles according to inclusion/exclusion criteria for data collection after title/abstract and full text screening. Of these 3 where epidemiological studies, 34 where in vivo studies in mice and rats and 2 were in vitro studies. The three epidemiological studies reported from the same longitudinal study and suggested that MDMA exposure during pregnancy impairs neuromotor function in infants. In rat, postnatal exposure towards MDMA also caused locomotor deficits as well as impaired spatial learning that might be associated with decreased serotonin levels in the hippocampus. In vitro MDMA caused cytotoxicity at high concentrations and effects on the serotonergic and neuritogenic alterations at lower concentrations which are in line with some of the in vivo alterations observed. Considering the adverse outcomes of developmental MDMA described in humans and in rodents we summarized the first putative AOP on developmental compound exposure leading to impaired neuromotor function in children. For generation of this AOP, MDMA exposure was taken as a model compound. In addition, we hypothesized a second AOP involving developmental disturbance of the dopaminergic system. However, further in vitro mechanistic studies are needed to understand the molecular initiating event(s) (MIE) triggering the downstream cascades and obtain consistent evidences causally linking the adverse outcome to effects at the cellular, organ and organism level.

Implementation of a functional endpoint to the zebrafish embryotoxicity test to evaluate craniofacial abnormalities

The inclusion of a read-out to detect functional consequences of craniofacial alterations in the zebrafish embryotoxicity test will allow to evaluate these alterations which are difficult to assess morphologically, and to detect alterations in cranial nerves functions leading to impairment of jaw movements. In this study we have established an ingestion test in zebrafish larvae younger than 120 hpf. To overcome the challenge of evaluating larvae which still do not present independent feeding behaviour, we have tested the ability of 72, 96 or 102 hpf larvae to ingest food mixed with fluorescent microspheres under several conditions (dark/light, with/without shaking) to find the best experimental set-up for the test. We have included the investigation of two substances as potential positive controls: ketoconazole and tricaine. Ketoconazole 10 μM exposure during development produced significant embryotoxic effects including a characteristic craniofacial alteration pattern consisting in impaired development of brain, nasal cavity, mouth opening and jaw, as well as a significant decrease in food intake. Tricaine exposure at 380 μM during the food availability period significantly decreased the food intake. The method proposed will be a useful alternative tool to animal testing to detect compounds inducing adverse effects on craniofacial development.

Current Availability of Stem Cell-Based In Vitro Methods for Developmental Neurotoxicity (DNT) Testing

There is evidence that chemical exposure during development can cause irreversible impairments of the human developing nervous system. Therefore, testing compounds for their developmentally neurotoxic potential has high priority for different stakeholders: academia, industry, and regulatory bodies. Due to the resource-intensity of current developmental neurotoxicity (DNT) in vivo guidelines, alternative methods that are scientifically valid and have a high predictivity for humans are especially desired by regulators. Here, we review availability of stem-/progenitor cell-based in vitro methods for DNT evaluation that is based on the concept of neurodevelopmental process assessment. These test methods are assembled into a DNT in vitro testing battery. Gaps in this testing battery addressing research needs are also pointed out.

Development of the Concept for Stem Cell-Based Developmental Neurotoxicity Evaluation

Human brain development consists of a series of complex spatiotemporal processes that if disturbed by chemical exposure causes irreversible impairments of the nervous system. To evaluate a chemical disturbance in an alternative assay, the concept evolved that the complex procedure of brain development can be disassembled into several neurodevelopmental endpoints which can be represented by a combination of different alternative assays. In this review article, we provide a scientific rationale for the neurodevelopmental endpoints that are currently chosen to establish assays with human stem/and progenitor cells. Assays covering these major neurodevelopmental endpoints are thought to assemble as building blocks of a DNT testing battery.

Dual-drug loaded nanoparticles of Epigallocatechin-3-gallate (EGCG)/Ascorbic acid enhance therapeutic efficacy of EGCG in a APPswe/PS1dE9 Alzheimer's disease mice model

Epigallocatechin-3-gallate (EGCG) is a candidate for treatment of Alzheimer's disease (AD) but its inherent instability limits bioavailability and effectiveness. We found that EGCG displayed increased stability when formulated as dual-drug loaded PEGylated PLGA nanoparticles (EGCG/AA NPs). Oral administration of EGCG/AA NPs in mice resulted in EGCG accumulation in all major organs, including the brain. Pharmacokinetic comparison of plasma and brain accumulation following oral administration of free or EGCG/AA NPs showed that, whilst in both cases initial EGCG concentrations were similar, long-term (5–25 h) concentrations were ca. 5 fold higher with EGCG/AA NPs. No evidence was found that EGCG/AA NPs utilised a specific pathway across the blood-brain barrier (BBB). However, EGCG, empty NPs and EGCG/AA NPs all induced tight junction disruption and opened the BBB in vitro and ex vivo. Oral treatment of APPswe/PS1dE9 (APP/PS1) mice, a familial model of AD, with EGCG/AA NPs resulted in a marked increase in synapses, as judged by synaptophysin (SYP) expression, and reduction of neuroinflammation as well as amyloid β (Aβ) plaque burden and cortical levels of soluble and insoluble Aβ_(1-42) peptide. These morphological changes were accompanied by significantly enhanced spatial learning and memory. Mechanistically, we propose that stabilisation of EGCG in NPs complexes and a destabilized BBB led to higher therapeutic EGCG concentrations in the brain. Thus EGCG/AA NPs have the potential to be developed as a safe and strategy for the treatment of AD.

Characterizing the multiple roles of FGF-2 in SOD1G93A ALS mice in vivo and in vitro

We have previously shown that knockout of fibroblast growth factor-2 (FGF-2) and potential compensatory effects of other growth factors result in amelioration of disease symptoms in a transgenic mouse model of amyotrophic lateral sclerosis (ALS). ALS is a rapidly progressive neurological disorder leading to degeneration of cortical, brain stem, and spinal motor neurons followed by subsequent denervation and muscle wasting. Mutations in the superoxide dismutase 1 (SOD1) gene are responsible for approximately 20% of familial ALS cases and SOD1 mutant mice still are among the models best mimicking clinical and neuropathological characteristics of ALS. The aim of the present study was a thorough characterization of FGF-2 and other growth factors and signaling effectors in vivo in the SOD1^G93A mouse model. We observed tissue-specific opposing gene regulation of FGF-2 and overall dysregulation of other growth factors, which in the gastrocnemius muscle was associated with reduced downstream extracellular-signal-regulated kinases (ERK) and protein kinase B (AKT) activation. To further investigate whether the effects of FGF-2 on motor neuron death are mediated by glial cells, astrocytes lacking FGF-2 were cocultured together with mutant SOD1 ^G93A motor neurons. FGF-2 had an impact on motor neuron maturation indicating that astrocytic FGF-2 affects motor neurons at a developmental stage. Moreover, neuronal gene expression patterns showed FGF-2- and SOD1 ^G93A -dependent changes in ciliary neurotrophic factor, glial-cell-line-derived neurotrophic factor, and ERK2, implying a potential involvement in ALS pathogenesis before the onset of clinical symptoms.

A transcriptome comparison of time-matched developing human, mouse and rat neural progenitor cells reveals human uniqueness

It is widely accepted that human brain development has unique features that cannot be represented by rodents. Obvious reasons are the evolutionary distance and divergent physiology. This might lead to false predictions when rodents are used for safety or pharmacological efficacy studies. For a better translation of animal-based research to the human situation, human in vitro systems might be useful. In this study, we characterize developing neural progenitor cells from prenatal human and time-matched rat and mouse brains by analyzing the changes in their transcriptome profile during neural differentiation. Moreover, we identify hub molecules that regulate neurodevelopmental processes like migration and differentiation. Consequences of modulation of three of those hubs on these processes were studied in a species-specific context. We found that although the gene expression profiles of the three species largely differ qualitatively and quantitatively, they cluster in similar GO terms like cell migration, gliogenesis, neurogenesis or development of multicellular organism. Pharmacological modulation of the identified hub molecules triggered species-specific cellular responses. This study underlines the importance of understanding species differences on the molecular level and advocates the use of human based in vitro models for pharmacological and toxicological research.

Epigallocatechin-3-gallate loaded PEGylated-PLGA nanoparticles: A new anti-seizure strategy for temporal lobe epilepsy

Temporal lobe epilepsy is the most common type of pharmacoresistant epilepsy in adults. Epigallocatechin-3-gallate has aroused much interest because of its multiple therapeutic effects, but its instability compromises the potential effectiveness. PEGylated-PLGA nanoparticles of Epigallocatechin-3-gallate were designed to protect the drug and to increase the brain delivery. Nanoparticles were prepared by the double emulsion method and cytotoxicity, behavioral, Fluoro-Jade C, Iba1 and GFAP immunohistochemistry studies were carried out to determine their effectiveness. Nanoparticles showed an average size of 169 nm, monodisperse population, negative surface charge, encapsulation efficiency of 95% and sustained release profile. Cytotoxicity assays exhibited that these nanocarriers were non-toxic. Behavioral test showed that nanoparticles reduced most than free drug the number of epileptic episodes and their intensity. Neurotoxicity and immunohistochemistry studies confirmed a decrease in neuronal death and neuroinflammation. In conclusion, Epigallocatechin-3-gallate PEGylated-PLGA nanoparticles could be a suitable strategy for the treatment of temporal lobe epilepsy.

Is Intake of Flavonoid-Based Food Supplements During Pregnancy Safe for the Developing Child? A Literature Review

Due to potential health benefits and the general assumption that natural products are safe, there is an increasing trend in the general population - including pregnant women - to supplement their diet with flavonoid-based food supplements. In addition, preclinical studies aim to prevent developmental adverse effects induced by toxic substances, infections, maternal or genetic diseases of the unborn child by administration of flavonoids at doses far above those reached by normal diets. Because these substances do not undergo classical risk assessment processes, our aim was to review the available literature on the potential adverse effects of maternal diet supplementation with flavonoid-based products for the developing child. A systematic literature search was performed in three databases and screened following four exclusion criteria. Selected studies were classified into two groups: 1. Studies on the developmental toxicity of single flavonoids in vitro or in animals in vivo, and 2. Studies on the developmental toxicity of single flavonoids or on flavonoid-mixtures in humans. The data collected indicate that there is a concern for the safety of some flavonoids within realistic human exposure scenarios. This concern is accompanied by a tremendous lack of studies on safety of these compounds during development making definite safety decisions impossible. Besides studies of survival, especially the more specific developmental processes like nervous system development need to be addressed experimentally. Before new high-dose, flavonoid-based therapeutic strategies are developed for pregnant women further research on the safety of these compounds is clearly needed.

Developing and applying the adverse outcome pathway concept for understanding and predicting neurotoxicity

The Adverse Outcome Pathway (AOP) concept has recently been proposed to support a paradigm shift in regulatory toxicology testing and risk assessment. This concept is similar to the Mode of Action (MOA), in that it describes a sequence of measurable key events triggered by a molecular initiating event in which a stressor interacts with a biological target. The resulting cascade of key events includes molecular, cellular, structural and functional changes in biological systems, resulting in a measurable adverse outcome. Thereby, an AOP ideally provides information relevant to chemical structure-activity relationships as a basis for predicting effects of structurally similar compounds. AOPs could potentially also form the basis for qualitative and quantitative predictive modeling of the human adverse outcome resulting from molecular initiating or other key events for which higher-throughput testing methods are available or can be developed. A variety of cellular and molecular processes are known to be critical for normal function of the central (CNS) and peripheral nervous systems (PNS). Because of the biological and functional complexity of the CNS and PNS, it has been challenging to establish causative links and quantitative relationships between key events that comprise the pathways leading from chemical exposure to an adverse outcome in the nervous system. Following introduction of the principles of MOA and AOPs, examples of potential or putative adverse outcome pathways specific for developmental or adult neurotoxicity are summarized and aspects of their assessment considered. Their possible application in developing mechanistically informed Integrated Approaches to Testing and Assessment (IATA) is also discussed.

Epigallocatechin gallate (EGCG) inhibits adhesion and migration of neural progenitor cells in vitro

Food supplements based on herbal products are widely used during pregnancy as part of a self-care approach. The idea that such supplements are safe and healthy is deeply seated in the general population, although they do not underlie the same strict safety regulations than medical drugs. We aimed to characterize the neurodevelopmental effects of the green tea catechin epigallocatechin gallate (EGCG), which is now commercialized as high-dose food supplement. We used the "Neurosphere Assay" to study the effects and unravel underlying molecular mechanisms of EGCG treatment on human and rat neural progenitor cells (NPCs) development in vitro. EGCG alters human and rat NPC development in vitro. It disturbs migration distance, migration pattern, and nuclear density of NPCs growing as neurospheres. These functional impairments are initiated by EGCG binding to the extracellular matrix glycoprotein laminin, preventing its binding to β1-integrin subunits, thereby prohibiting cell adhesion and resulting in altered glia alignment and decreased number of migrating young neurons. Our data raise a concern on the intake of high-dose EGCG food supplements during pregnancy and highlight the need of an in vivo characterization of the effects of high-dose EGCG exposure during neurodevelopment.

Breath methane in functional constipation: response to treatment with Ispaghula husk

BACKGROUND

Colonic fermentation produces hydrogen (H2 ), and also produces methane (CH4 ) in subjects with methanogenic flora (M+). Methane production has been associated with chronic constipation (CC) and with changes in gut motility. To determine CH4 production in CC compared to controls, and to assess whether the therapeutic response to Ispaghula husk in CC differs between CH4 -producers and non-producers.

METHODS

Forty-eight patients with functional constipation or irritable bowel syndrome-constipation and 19 healthy age-and-sex-matched volunteers (HV) filled in a 1-week symptom diary and a dietary questionnaire. They then underwent a lactulose breath test (LBT) to measure H2 and CH4 production (peak and area under the time-concentration curve, AUC-) and a colonic transit time (CTT) assessment. In patients, measurements were repeated after a 4-week treatment with Ispaghula husk.

KEY RESULTS

Prevalence of M+ in patients was 60.5% vs 52.6% in HV (p = 0.37). Patients had significantly longer CTT and greater production of both H2 and CH4 during LBT. There was a significant correlation between CH4 production and CTT (r = 0.51; p = 0.07). Treatment response rate was similar for M+ and M- patients (58.3% vs 52.9%; p = 0.76) as were the increases in bowel movements and Bristol score, changes in abdominal discomfort and bloating. In M+, treatment reduced CTT (-10 ± 35 h; p = 0.029 vs baseline) and CH4 levels: peak CH4 (-13 ± 24 ppm; p = 0.014) and CH4 -AUC (-817 ± 3100 ppm/min; p = 0.04).

CONCLUSIONS & INFERENCES

Although CH4 production has been associated with CC pathophysiology, we found that CH4 status did not negatively affect the response to Ispaghula husk treatment. The measurement of CH4 levels as a biomarker tool for CC requires further appraisal.

Triclabendazole sulfoxide causes stage-dependent embryolethality in zebrafish and mouse in vitro

Background

Fascioliasis and paragonimiasis are widespread foodborne trematode diseases, affecting millions of people in more than 75 countries. The treatment of choice for these parasitic diseases is based on triclabendazole, a benzimidazole derivative which has been suggested as a promising drug to treat pregnant women and children. However, at the moment, this drug is not approved for human use in most countries. Its potential adverse effects on embryonic development have been scarcely studied, and it has not been assigned a pregnancy category by the FDA. Thus, to help in the process of risk-benefit decision making upon triclabendazole treatment during pregnancy, a better characterization of its risks during gestation is needed.

Methodology

The zebrafish embryo test, a preimplantation and a postimplantation rodent whole embryo culture were used to investigate the potential embryotoxicity/teratogenicity of triclabendazole and its first metabolite triclabendazole sulfoxide. Albendazole and albendazole sulfoxide were included as positive controls.

Principal Findings

Triclabendazole was between 10 and 250 times less potent than albendazole in inducing dysmorphogenic effects in zebrafish or postimplantation rodent embryos, respectively. However, during the preimplantation period, both compounds, triclabendazole and triclabendazole sulfoxide, induced a dose-dependent embryolethal effect after only 24 h of exposure in rodent embryos and zebrafish (lowest observed adverse effect concentrations = 10 μM).

Conclusions/Significance

In humans, after ingestion of the recommended doses of triclabendazole to treat fascioliasis and paragonimiasis (10 mg/kg), the main compound found in plasma is triclabendazole sulfoxide (maximum concentration 38.6 μM), while triclabendazole concentrations are approximately 30 times lower (1.16 μM). From our results it can be concluded that triclabendazole, at concentrations of the same order of magnitude as the clinically relevant ones, does not entail teratogenic potential in vitro during the organogenesis period, but its first metabolite triclabendazole sulfoxide has a high embryotoxic capacity in vitro during the preimplantation stage.

Heavy metal and metalloids intake risk assessment in the diet of a rural population living near a gold mine in the Peruvian Andes (Cajamarca)

This study evaluates the diet composition of a rural population near a gold mine in the Cajamarca district of Peru. The main consumed items by this population were tubers and cereals, and the mean energy intake (1990 kcal) was shown not to cover the recommended intake values for the male population. The concentrations of As, Cd, Hg, Pb, Zn, Al, Cr and, Cu in drinking water and food samples of items contributing to 91% of this diet (145 samples, 24 different items) were determined and used to calculate their daily intakes for risk assessment. The As, Cd and Pb daily intakes exceeded the limit values established by the European Food Safety Authority (EFSA), entailing serious concerns for the population's health. Moreover, the intake values of As and Pb were shown to be higher, the closer to the gold mine the studied population was.

Automatic counting and positioning of 5-bromo-2-deoxyuridine (BrdU) positive cells in cortical layers of rat brain slices

5-Bromo-2-deoxyuridine (BrdU) staining is often used to evaluate cortical layer formation during mammalian brain development. This method allows the quantification of newly generated cells and therefore the study of the effects of xenobiotics or genetic factors on proliferation, cell death and migration behavior in a quantitative manner. However, these endpoints are generally assessed by time-consuming manual evaluation. In the present work, we introduce a novel procedure to identify and quantify BrdU(+) cells within cortical layers, using the commercially available vHCS-Scan V.6.3.1 software to identify BrdU(+) cell coordinates and the novel program 'BrdeLuxe' to define cortical layers and quantitatively assign BrdU(+) cells to them. This procedure is compared to BrdU(+) cell counting with the freeware 'ImageJ' in respect to the manual evaluation, all by two different researchers. BrdeLuxe shows high accuracy and precision for the determination of total number of BrdU(+) cells compared to the manual counting, while ImageJ does not reach such results. Accuracy and precision are also higher for employing the BrdeLuxe program to evaluate the percentage of BrdU(+) cells per brain layer compared to ImageJ. In terms of running time, BrdeLuxe is the fastest method of the three making it more suitable for multiple brain slices analyses.

Comparative human and rat "neurosphere assay" for developmental neurotoxicity testing

The developing nervous system is highly vulnerable to the adverse effects of chemical agents. Currently, there is an increasing need for testing and regulating chemical compounds in general use and, due to the lack of available data, to identify those which are developmental neurotoxicants. In this context, alternative testing strategies are needed in order to allow fast and cost-efficient screening and to reduce the number of animal experiments usually required. In this unit we present an in vitro three-dimensional model for developmental neurotoxicity screening based on human and rat neural progenitor cells. This model enables the detection of disturbances in basic processes of brain development, such as proliferation, migration, differentiation and apoptosis, and allows the distinction of these specific disturbances from general cytotoxicity. Furthermore, the comparison of human and rat data provides useful insights into species differences for toxicodynamics of compounds contributing to human risk assessment of developmental neurotoxicants.

High-dose, ten-day esomeprazole, amoxicillin and metronidazole triple therapy achieves high Helicobacter pylori eradication rates

BACKGROUND

Strong acid inhibition using esomeprazole increases cure rates with triple therapy and 10-day treatments are more effective than 7-day ones. The combination of amoxicillin plus metronidazole at full doses, and using a physiologically-correct schedule three times a day, and has been shown to overcome metronidazole resistance and to achieve good eradication rates.

AIMS

To assess the eradication rate of a new first-line treatment regimen associating strong acid inhibition, amoxicillin and metronidazole and to evaluate tolerance.

METHODS

Patients from eight hospitals were included. Helicobacter pylori status was assessed by at least one of the following: histology, culture, rapid urease test or urea breath test (UBT). Ten-day treatment was prescribed comprising esomeprazole 40 mg twice a day plus amoxicillin 1 g and metronidazol 500 mg both three times a day. Helicobacter pylori cure was assessed by UBT.

RESULTS

A hundred and thirty-six patients were enrolled. Mean age was 52.6 ± 16 years and 59.6% of patients were men. Main indications for treatment were: uninvestigated dyspepsia (13.6%); functional dyspepsia (18.2%); gastric ulcer (21.8%); and duodenal ulcer (39.8%). Helicobacter pylori eradication was achieved in 112 of the 127 patients who returned for follow-up. Eradication rates were 82.4% (95% CI: 74.7-88.1) by intention-to-treat analysis and 88.2% (95% CI: 81.2-92.8) by per protocol. Treatment was well tolerated and no major side effects were reported. Nine patients complained of mild side effects.

CONCLUSIONS

Cure rates of the combination of esomeprazole, amoxicillin and metronidazole are high and the treatment was well tolerated. This pilot study warrants the comparison of this schedule with current standards.

Comparison of the mouse Embryonic Stem cell Test, the rat Whole Embryo Culture and the Zebrafish Embryotoxicity Test as alternative methods for developmental toxicity testing of six 1,2,4-triazoles

The relatively high experimental animal use in developmental toxicity testing has stimulated the search for alternatives that are less animal intensive. Three widely studied alternative assays are the mouse Embryonic Stem cell Test (EST), the Zebrafish Embryotoxicity Test (ZET) and the rat postimplantation Whole Embryo Culture (WEC). The goal of this study was to determine their efficacy in assessing the relative developmental toxicity of six 1,2,4-triazole compounds,(1) flusilazole, hexaconazole, cyproconazole, triadimefon, myclobutanil and triticonazole. For this purpose, we analyzed effects and relative potencies of the compounds in and among the alternative assays and compared the findings to their known in vivo developmental toxicity. Triazoles are antifungal agents used in agriculture and medicine, some of which are known to induce craniofacial and limb abnormalities in rodents. The WEC showed a general pattern of teratogenic effects, typical of exposure to triazoles, mainly consisting of reduction and fusion of the first and second branchial arches, which are in accordance with the craniofacial malformations reported after in vivo exposure. In the EST all triazole compounds inhibited cardiomyocyte differentiation concentration-dependently. Overall, the ZET gave the best correlation with the relative in vivo developmental toxicities of the tested compounds, closely followed by the EST. The relative potencies observed in the WEC showed the lowest correlation with the in vivo developmental toxicity data. These differences in the efficacy between the test systems might be due to differences in compound kinetics, in developmental stages represented and in the relative complexity of the alternative assays.