Assessment Of Neurotoxicity Research Articles

The regulatory effects of mitragynine on P-glycoprotein transporter.

Kratom preparation containing Mitragyna speciosa Korth plant is frequently used as a recreational drug. Mitragynine, a major alkaloid isolated from M. speciosa, is often detected concurrently with other drugs during forensic analysis, indicating a safety concern. P-glycoprotein (P-gp) is a multidrug transporter. Modulation of P-gp transport activity by drugs or herbal compounds in the brain may lead to drug-herb interactions, resulting in neurotoxicity. We aim to determine the effects of mitragynine on the P-gp regulation and possible neurotoxicity. The effects of mitragynine on the P-gp regulation were investigated in human brain capillary endothelial cells (hCMEC/D3) using molecular docking and dynamic simulation and an optimized bidirectional transport assay, respectively. Repeated-dose treatment and neurotoxicity assessment were carried out using a blood-brain barrier model and polimerase chain reaction (PCR) array. Mitragynine inhibits the P-gp transport activity via binding onto the nucleotide-binding domain site and forms a stable interaction with the P-gp protein complex. Nontoxic concentrations of mitragynine (<4 μM) and substrate drugs (0.001 μM) in the cells significantly enhanced endothelial cell permeability and elicited signs of neurotoxicity in PC-12 cells. Mitragynine is likely a P-gp inhibitor, hence concurrent administration of kratom products with P-gp substrates may lead to clinically significant interactions and neurotoxicity.

Development of a Novel Microphysiological System for Peripheral Neurotoxicity Prediction Using Human iPSC-Derived Neurons with Morphological Deep Learning

A microphysiological system (MPS) is an in vitro culture technology that reproduces the physiological microenvironment and functionality of humans and is expected to be applied for drug screening. In this study, we developed an MPS for the structured culture of human iPSC-derived sensory neurons and then predicted drug-induced neurotoxicity by morphological deep learning. Using human iPSC-derived sensory neurons, after the administration of representative anti-cancer drugs, the toxic effects on soma and axons were evaluated by an AI model with neurite images. Significant toxicity was detected in positive drugs and could be classified by different effects on soma or axons, suggesting that the current method provides an effective evaluation of chemotherapy-induced peripheral neuropathy. The results of neurofilament light chain expression changes in the MPS device also agreed with clinical reports. Therefore, the present MPS combined with morphological deep learning is a useful platform for in vitro peripheral neurotoxicity assessment.

Early diagnosis of nonconvulsive status epilepticus due to lithium intoxication using 6-channel electroencephalography.

Nonconvulsive status epilepticus is a severe complication of lithium intoxication that requires prompt diagnosis and treatment. While conventional electroencephalography (EEG) remains the gold standard for diagnosis for nonconvulsive status epilepticus, its implementation in emergency settings can be challenging and time-consuming. We present a case in which simplified EEG with six electrodes enabled rapid detection and monitoring of nonconvulsive status epilepticus in lithium intoxication in the emergency setting. A 65-year-old woman with stable bipolar disorder presented to our emergency department with impaired consciousness. She had been maintained on lithium carbonate (1600mg daily) and carbamazepine (400mg daily) for over 10 years. Following two weeks of nausea and recent onset of agitation and slurred speech, she developed generalized convulsions. Laboratory examinations revealed elevated serum lithium (3.88 mEq/L) and acute renal dysfunction (creatinine 347.5μmol/L). After resolving initial convulsions, a simplified sixelectrode EEG (Neurofax EEG-1250, Nihon Kohden Corporation, Tokyo, Japan), applied by an emergency physician, demonstrated generalized spike and wave patterns consistent with nonconvulsive status epilepticus. Despite initial seizure control with midazolam during intubation, continuous EEG monitoring revealed recurrent nonconvulsive status epilepticus. After hemodialysis and continued deep sedation, she was discharged on day 40 without neurological sequelae. This case demonstrates the utility of simplified EEG in emergency settings for early detection and monitoring of nonconvulsive status epilepticus in lithium intoxication. The ability of emergency physicians to apply and interpret simplified EEG enabled timely intervention and prevention of neurological complications. While further research is needed to validate interpretation protocols by non-EEG specialists, simplified EEG shows promise as an accessible tool for rapid assessment of neurotoxicity in lithium intoxication, potentially improving patient outcomes through earlier intervention.

Risk assessment of developmental and neurotoxicity by the flavoring agent perillaldehyde: NAC (N-acetylcysteine) mitigation of oxidative stress-mediated inhibition of the Nrf2 pathway.

Perillaldehyde (PAE), a prevalent flavoring agent, has raised safety concerns due to conflicting evidence regarding its toxicity. This study provides a comprehensive assessment of the developmental and neurotoxic effects of PAE in zebrafish, elucidating the underlying mechanisms of its toxicity. Results showed that PAE affected the viability and hatching rate of zebrafish at 96 h postfertilization with the 50 % lethal concentration (LC50) of 7.975 mg/L. Furthermore, exposed‌ to a non-lethal concentration of 4 mg/L PAE induced a spectrum of morphological abnormalities, such as pericardial edema, delayed yolk sac absorption, reduced body length, and microphthalmia. Behavioral observations revealed that PAE reduced motor ability, and was accompanied by an increase in spontaneous turning angle and angular velocity. Using the TG(elav13:EGFP) transgenic model, we observed the number of newborn neurons was reduced, indicating that PAE induced obvious neurotoxic effects. Additionally, this concentration facilitated the accumulation of reactive oxygen species (ROS) and malondialdehyde (MDA), concomitantly decreasing the activity of antioxidant enzymes. QRT-PCR analysis revealed that PAE down-regulated Nestin and Neurogenin1 gene expression, up-regulated Glipr1a and Nox1 gene expression, and inhibited the Nrf2/HO-1 pathway. Notably, co-administration of N-acetylcysteine (NAC), an inhibitor of oxidative stress, mitigated oxidative stress levels and partially ameliorated the neurotoxicity. These findings suggest that oxidative stress is the primary mediator of PAE-induced neurotoxicity. This study provides crucial insights for the safe application of PAE.

Dynamic culture of cerebral organoids using a pillar/perfusion plate for the assessment of developmental neurotoxicity

Despite the potential toxicity of commercial chemicals to the development of the nervous system (known as developmental neurotoxicity or DNT), conventionalin vitrocell models have primarily been employed for the assessment of acute neuronal toxicity. On the other hand, animal models used for the assessment of DNT are not physiologically relevant due to the heterogenic difference between humans and animals. In addition, animal models are low-throughput, time-consuming, expensive, and ethically questionable. Recently, human brain organoids have emerged as a promising alternative to assess the detrimental effects of chemicals on the developing brain. However, conventional organoid culture systems have several technical limitations including low throughput, lack of reproducibility, insufficient maturity of organoids, and the formation of the necrotic core due to limited diffusion of nutrients and oxygen. To address these issues and establish predictive DNT models, cerebral organoids were differentiated in a dynamic condition in a unique pillar/perfusion plate, which were exposed to test compounds to evaluate DNT potential. The pillar/perfusion plate facilitated uniform, dynamic culture of cerebral organoids with improved proliferation and maturity by rapid, bidirectional flow generated on a digital rocker. Day 9 cerebral organoids in the pillar/perfusion plate were exposed to ascorbic acid (DNT negative) and methylmercury (DNT positive) in a dynamic condition for 1 and 3 weeks, and changes in organoid morphology and neural gene expression were measured to determine DNT potential. As expected, ascorbic acid did not induce any changes in organoid morphology and neural gene expression. However, exposure of day 9 cerebral organoids to methylmercury resulted in significant changes in organoid morphology and neural gene expression. Interestingly, methylmercury did not induce adverse changes in cerebral organoids in a static condition, thus highlighting the importance of dynamic organoid culture in DNT assessment.

Neonicotinoid pesticides: evidence of developmental neurotoxicity from regulatory rodent studies.

Neonicotinoids are the most widely used class of insecticides in the United States (U.S.). and the world. Consistent with their high use and persistence, neonicotinoids are often found contaminating drinking water and food. They are also detected in human urine, breast milk, amniotic and cerebrospinal fluids, as well as the brains of treated rodents. Neonicotinoids were once thought to pose little neurotoxic risk to humans, but a growing body of research challenges that assumption. In this study we provide the first comprehensive assessment of unpublished rodent developmental neurotoxicity (DNT) studies on five neonicotinoids that were submitted to the U.S. Environmental Protection Agency (EPA) by neonicotinoid manufacturers. Groups of female rats were administered three different doses of a neonicotinoid during pregnancy and lactation, and their offspring subjected to various neurological tests and brain measurements. We identified nicotine-like effects such as reduced brain size, indicative of neuronal cell loss. Statistically significant shrinkage of brain tissue was observed in high-dose offspring for five neonicotinoids: acetamiprid, clothianidin, imidacloprid, thiacloprid, and thiamethoxam. Two brain regions reduced in the rodent studies-the corpus callosum and caudate-putamen-tend to be smaller in people diagnosed with attention-deficit hyperactivity disorder (ADHD), and in children of mothers who smoked during pregnancy, suggesting a possible link between perinatal neonicotinoid exposure and ADHD. A decreased auditory startle reflex was reported for acetamiprid at all doses and was statistically significant in the mid- and high-dose offspring, and for clothianidin in juvenile high-dose females. No mid- or low-dose brain morphometric data were submitted for acetamiprid, imidacloprid, or thiacloprid. Thiamethoxam mid- and low-dose brain morphometric data were provided to EPA upon request. Only partial mid-dose brain morphometry data were submitted for clothianidin, but no low-dose data. Yet despite this lack of data, EPA concluded that only the high-dose brain morphometric effects were treatment-related-setting the mid-dose as the study's No Observed Adverse Effect Level (NOAEL) or failing to find a definitive NOAEL for acetamiprid, clothianidin, imidacloprid, thiacloprid and thiamethoxam. We found numerous deficiencies in EPA's regulatory oversight and data analyses. EPA dismissed statistically significant adverse effects, accepted substandard DNT studies despite lack of valid positive control data, and allowed neonicotinoid registrants to unduly influence agency decision-making. We conclude that perinatal exposure to neonicotinoids and their metabolites induces adverse, nicotine-like neurotoxic effects in rodent bioassays, and that the exposure limits set by EPA for human exposure are either not protective or not supported by available neurotoxicity data. We propose regulatory changes to empower EPA to better protect public health from developmental neurotoxins like neonicotinoids.

High-Throughput Assessment of Metabolism-Mediated Neurotoxicity by Co-Culture of Neurospheres and Liver Spheroids.

The liver's role in the biotransformation of chemicals is critical for both augmented toxicity and detoxification. However, there has been a significant lack of effort to integrate biotransformation into in vitro neurotoxicity testing. Traditional in vitro neurotoxicity testing systems are unable to assess the qualitative and quantitative differences between parent chemicals and their metabolites as they would occur in the human body. As a result, traditional in vitro toxicity screening systems cannot incorporate hepatic biotransformation to predict the neurotoxic potential of chemical metabolites. To bridge this gap, a high-throughput, metabolism-mediated neurotoxicity testing system has been developed, which combines metabolically competent HepaRG cell spheroids with a three-dimensional (3D) culture of ReNcell VM human neural progenitor cell line. The article outlines protocols for generating HepaRG cell spheroids using an ultralow attachment (ULA) 384-well plate and for cultivating ReNcell VM in 3D on a 384-pillar plate with sidewalls and slits (384PillarPlate). Metabolically sensitive test compounds are introduced into the ULA 384-well plate containing HepaRG spheroids and then tested with 3D-cultured ReNcell VM on the 384PillarPlate. This configuration permits the in situ generation of metabolites by HepaRG cells and their subsequent testing on neurospheres. By analyzing cell viability data, researchers can determine the IC50 values for each compound, thus evaluating metabolism-mediated neurotoxicity. © 2024 Wiley Periodicals LLC. Basic Protocol 1: HepaRG spheroid culture in an ultralow attachment (ULA) 384-well plate and the assessment of drug-metabolizing enzyme (DME) activities Basic Protocol 2: 3D neural stem cell (NSC) culture on a 384PillarPlate and compound treatment for the assessment of metabolism-mediated neurotoxicity Basic Protocol 3: Image acquisition, processing, and data analysis.

In vivo assessment of oxidative stress, neurotoxicity and histological alterations induction in the marine gastropod Stramonita haemastoma exposed to Cr2O3 and Al2O3 nanoparticles

The increased use of nanoparticles (NPs) is expected to raise their presence in the marine ecosystem, which is considered as the final destination of released NPs. This study investigated the toxicity of Cr2O3 (42 nm) and Al2O3 (38 nm) NPs (1, 2.5, and 5 mg/L) on the digestive glands of Stramonita haemastoma for 7, 14, and 28 days by oxidative stress biomarkers, neurotoxicity indicator assessment, and histological study. Results revealed an imbalance in antioxidants at all periods. Following 7 days, both NPs caused GSH depletion with marked impacts from Al2O3. GPx, CAT, and AChE were also decreased with the highest changes induced by Cr2O3. Both NPs inducted GSH and GST levels on days 14 and 28, with more effects from Cr2O3 exposure. GPx, AChE, and MDA induction were observed on day 28, while MT varied through NPs and time, with imbalanced levels at all periods noticed, SOD was mostly not affected. Histology revealed alterations including necrosis and interstitial deteriorations; quantitative analysis through the histological condition index revealed dose-dependent impacts, with the highest values attributed to Cr2O3 exposure. While PCA revealed the co-response of GSH, GST, GPx, CAT, and AchE with separated MT responses. This study reported oxidative stress induction through a multi-biomarkers investigation, neurotoxicity, and histological damages in the digestive gland of S. haemastoma following Cr2O3 and Al2O3 NPs exposure.

Comparative assessment of acute neurotoxicity of real-world ultra-fine black carbon emitted from residential solid fuel combustion

Incomplete combustion of residential solid fuel is one of the main anthropogenic sources for black carbon (BC). Fresh BC, mainly enriched in ultra-fine fraction of particles, can directly cross blood-brain barrier and are reported to be associated with neurodegenerative diseases. Because of the difficulties in collection and purification of BC from ambient particles, there are still significant knowledge gaps in understanding neurotoxicity caused by real-world BC. The purpose of this study is to compare the neurotoxic effects caused by BCs emitted from combustion of six residential solid fuels, and try to reveal associated biological mechanisms in SH-SY5Y cells. Two straw BC (Wheat-BC and Corn-BC) showed highest neurotoxic effects followed by wood BC (Pine-BC and Aspen-BC) and coal BC (Xvzhou and Longkou Coal), as indicated by viability, lactic dehydrogenase, malondialdehyde, adenosine triphosphate and acetylcholine levels. Coal BC caused nearly no toxicity in human neuroblastoma (SH-SY5Y) cells within highest dose of 200 μg/mL. RNA sequence and bioinformatics analysis were applied to effectively identify differential genes and signaling pathways. Based on Gene Ontology (GO) annotation, Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment, Protein Protein Interaction network (PPI network) construction, we found biomass BC affected mitochondrial function, interfered with cellular metabolic processes, disturbed redox homeostasis, and finally resulted in cellular damages. Coal-BC mainly caused cytokine/chemokine related inflammatory responses. Reverse transcription quantitative polymerase chain reaction (RT-qPCR) and Western blotting methods were further applied to find out related signaling pathways. Biomass BC activated IL6R/JAK3/STAT3 and JAK3/STAT6 pathways leading to oxidative stress and inflammatory responses. Coal BC activated JAK3/STAT3 pathway leading to chemokine related responses. This study revealed the heterogeneity in neurotoxicity of BCs from different combustion sources and provided important data for health risk assessment. BC-related neurotoxicity should be considered when making air pollution emission control strategies, with residential biomass receiving more policy attention.

Biochemical responses of crayfish exposed to imidacloprid: assessment of oxidative stress, osmoregulatory response and neurotoxicity

ABSTRACT Among the nicotinoid insecticides, imidacloprid (IMI) may affect non-target invertebrates like aquatic crustaceans by entering the aquatic environment through rainfall. Nevertheless, there are not sufficient studies on the toxicity mechanism of IMI in crayfish. Here, we investigated the effects of IMI on oxidative stress, osmoregulatory, and neurotoxicity biomarkers. The 96-hour lethal concentration value (96 h-LC50) of IMI was determined to be 0.932 mg AI L−1. Four concentrations of IMI (0.932, 0.466, 0.233 and 0.117 mg AI L−1) were applied to crayfish for 96 h. Na+/K+-ATPase, Mg2+-ATPase, Ca2+-ATPase, and total ATPase activities had almost significantly concentration-related inhibition in both gill and muscle tissues (p < 0.05). Compare with control in hepatopancreas, the activities of GST, SOD and GPx were increased, while the activities of AChE, CES and GR were decreased (p < 0.05). As non-enzymatic parameters, a statistically significant (p < 0.05) increase in MDA levels and a decrease in GSH levels were observed in the hepatopancreas compared to the control group, which was not related to the concentration. In conclusion, it can be said that the study's biomarkers are highly helpful and that commercially consumed crayfish are a significant non-target organism in the assessment of IMI toxicity.

P09-04 Assessment of developmental neurotoxicity of imidacloprid on hippocampal neurogenesis and cerebellum in rat offspring

P09-04 Assessment of developmental neurotoxicity of imidacloprid on hippocampal neurogenesis and cerebellum in rat offspring

CEC01-06 Flash talk: use of adverse outcome pathways as an organizing framework for integrated approaches to testing and assessment of developmental neurotoxicity of pesticides

CEC01-06 Flash talk: use of adverse outcome pathways as an organizing framework for integrated approaches to testing and assessment of developmental neurotoxicity of pesticides

Do Microplastics Have Neurological Implications in Relation to Schizophrenia Zebrafish Models? A Brain Immunohistochemistry, Neurotoxicity Assessment, and Oxidative Stress Analysis.

The effects of exposure to environmental pollutants on neurological processes are of increasing concern due to their potential to induce oxidative stress and neurotoxicity. Considering that many industries are currently using different types of plastics as raw materials, packaging, or distribution pipes, microplastics (MPs) have become one of the biggest threats to the environment and human health. These consequences have led to the need to raise the awareness regarding MPs negative neurological effects and implication in neuropsychiatric pathologies, such as schizophrenia. The study aims to use three zebrafish models of schizophrenia obtained by exposure to ketamine (Ket), methionine (Met), and their combination to investigate the effects of MP exposure on various nervous system structures and the possible interactions with oxidative stress. The results showed that MPs can interact with ketamine and methionine, increasing the severity and frequency of optic tectum lesions, while co-exposure (MP+Met+Ket) resulted in attenuated effects. Regarding oxidative status, we found that all exposure formulations led to oxidative stress, changes in antioxidant defense mechanisms, or compensatory responses to oxidative damage. Met exposure induced structural changes such as necrosis and edema, while paradoxically activating periventricular cell proliferation. Taken together, these findings highlight the complex interplay between environmental pollutants and neurotoxicants in modulating neurotoxicity.

Comprehensive Assessment of Drug Kinetics, Neurotoxicity, and Safety of Sirolimus-Eluting Intracranial Stents in Canine Basilar Artery.

Sirolimus-eluting stents (SESs) have shown promise in treating intracranial atherosclerosis but concerns about potential neurotoxicity due to prolonged drug release exist. The aim of this study was to comprehensively assess the safety of SES, with a focus on neurotoxicity. Stents (1.50 × 7 or 12 mm) were implanted into the basilar arteries of 154 Labrador Retrievers (weighing >25 kg and aged older than 1 year) divided into 4 groups: baer-metal stent, polymer-coated stent, standard-dose SES (sirolimus dose: 71 μg), and high-dose SES group (sirolimus dose: 284 μg). Pharmacokinetic analysis was conducted using liquid chromatography-mass spectrometry on blood and tissue samples, and analysis of brain tissue was performed with 5 different special stains and immunohistochemistry protocols to assess axonal degeneration, vacuolization, astrocyte proliferation, microglial activation, or widespread neurodegeneration. In the standard-dose SES group, the stent released 10.56% of the drug on day 1 and 95.41% on day 28 postimplantation. In the high-dose SES group, corresponding figures were 40.20% on day 1 and 98.08% on day 28. Systemic drug concentration consistently remained below 1.5 ng/mL throughout the study. Arterial tissue concentration reached its peak at day 28 days in the standard-dose group and at 7 days in the high-dose group. Importantly, the brain and related tissue concentrations remained below 0.4 µg/g in both standard-dose and high-dose SES groups, peaking on day 21 in the standard-dose group and day 1 in the high-dose group. The detailed 180-day safety assessment revealed no adverse effects on the brain, even at high sirolimus doses in the SES group. This study provides robust evidence supporting the long-term pharmacokinetic safety of SESs in the context of intracranial interventions for high-grade intracranial atherosclerosis. The results adequately alleviate concerns related to neurotoxicity and substantiate the feasibility of using these stents as a therapeutic choice in neurosurgery.

Enhanced electrophysiological activity and neurotoxicity screening of environmental chemicals using 3D neurons from human neural precursor cells purified with PSA-NCAM

The assessment of neurotoxicity for environmental chemicals is of utmost importance in ensuring public health and environmental safety. Multielectrode array (MEA) technology has emerged as a powerful tool for assessing disturbances in the electrophysiological activity. Although human embryonic stem cell (hESC)-derived neurons have been used in MEA for neurotoxicity screening, obtaining a substantial and sufficiently active population of neurons from hESCs remains challenging. In this study, we successfully differentiated neurons from a large population of human neuronal precursor cells (hNPC) purified using a polysialylated neural cell adhesion molecule (PSA-NCAM), referred to as hNPCPSA-NCAM+. The functional characterization demonstrated that hNPCPSA-NCAM+-derived neurons improve functionality by enhancing electrophysiological activity compared to total hNPC-derived neurons. Furthermore, three-dimensional (3D) neurons derived from hNPCPSA-NCAM+ exhibited reduced maturation time and enhanced electrophysiological activity on MEA. We employed subdivided population analysis of active mean firing rate (MFR) based on electrophysiological intensity to characterize the electrophysiological properties of hNPCPSA-NCAM+-3D neurons. Based on electrophysiological activity including MFR and burst parameters, we evaluated the sensitivity of hNPCPSA-NCAM+-3D neurons on MEA to screen both inhibitory and excitatory neuroactive environmental chemicals. Intriguingly, electrophysiologically active hNPCPSA-NCAM+-3D neurons demonstrated good sensitivity to evaluate neuroactive chemicals, particularly in discriminating excitatory chemicals. Our findings highlight the effectiveness of MEA approaches using hNPCPSA-NCAM+-3D neurons in the assessment of neurotoxicity associated with environmental chemicals. Furthermore, we emphasize the importance of selecting appropriate signal intensity thresholds to enhance neurotoxicity prediction and screening of environmental chemicals.

Insights into Triclosan-Induced Endocrine Disruption: Evidence from the National Health and Nutrition Examination Survey and Zebrafish Models.

Triclosan (TCS) has garnered significant attention due to its widespread use and associated endocrine-disrupting effects. However, its impact on the neuroendocrine system and underlying mechanisms remain poorly understood. Here, we established correlations between TCS exposure and serum sex hormone levels in participants of the National Health and Nutrition Examination Survey (NHANES). Additionally, we investigated TCS's influence on the neuroendocrine system using adult zebrafish exposed to environmentally relevant concentrations of TCS (0.361-48.2 μg/L) for 21 days. Assessment of reproductive and neurotoxicity included histopathological examination and behavioral tests. Transcriptomics, proteomics analyses, and biochemical detection were employed to elucidate mechanisms underlying TCS-induced neuroendocrine disruption. Significant correlations were found between TCS exposure and estradiol, testosterone, and sex hormone-binding globulin levels in NHANES participants. In addition, TCS exposure inhibited ovary development and spermatogenesis in zebrafish. Transcriptomics and proteomics analysis revealed gender-specific key signaling and metabolism-related pathways implicated in TCS-induced reproductive toxicity. Moreover, TCS exposure induced nervous system impairment, as evidenced by histological changes and altered motor behavior, possibly associated with oxidative damage. Correlation analysis further highlighted the potential connection between endocrine system disruption and nervous system impairment following TCS exposure. Overall, this study provided evidence supporting TCS-induced endocrine disruption and offered insights into its underlying mechanisms.

Assessment of the Developmental Neurotoxicity of Environmental Chemicals: Investigating the Mechanisms &amp; Identifying Potential Biomarkers

Background: Developmental neurotoxicity resulting from exposure to environmental chemicals is a significant public health concern. Understanding the mechanisms underlying such neurotoxicity and identifying potential biomarkers are essential for early detection and effective risk assessment. Objective: This study aimed to assess the developmental neurotoxicity of selected environmental chemicals and investigate the underlying mechanisms. Additionally, the study sought to identify potential biomarkers for early detection and monitoring of developmental neurotoxicity. Methods: In vitro neurodevelopmental models were established, including neuronal cell cultures and organoid systems, to evaluate the neurotoxic effects of environmental chemicals. Key endpoints, such as neuronal viability, morphology, neurite outgrowth, synaptogenesis, and synaptic activity, were assessed using appropriate assays and imaging techniques. Mechanistic investigations involved exploring oxidative stress, inflammation, disruption of neurotransmitter systems, and interference with neurodevelopmental processes through gene expression analysis, protein profiling, and signaling pathway investigations. Results: Exposure of the in vitro models to selected environmental chemicals resulted in significant neurotoxic effects, including impaired neuronal viability, disrupted morphological development, and altered synaptic activity. Mechanistic investigations revealed the involvement of oxidative stress and disruption of neurotransmitter systems in the observed neurotoxicity. Furthermore, several potential biomarkers, including gene expression changes and epigenetic modifications, showed significant correlations with developmental neurotoxicity. Conclusion: This study demonstrates the developmental neurotoxicity of environmental chemicals in in vitro neurodevelopmental models. The findings highlight the role of oxidative stress and neurotransmitter disruption as key mechanisms underlying neurotoxic effects. Moreover, the identification of potential biomarkers provides promising avenues for early detection and monitoring of developmental neurotoxicity. These results contribute to a better understanding of the risks associated with environmental chemical exposure during neurodevelopment and have implications for risk assessment and regulatory guidelines.

Abstract PO3-28-04: Ganglioside-Monosialic Acid for Prevention of Peripheral Neuropathy Induced by nab-Paclitaxel in Breast Cancer Patients (HELEN-004): A Randomized, Double-Blind, Phase II Trial

Abstract Introduction Chemotherapy-induced peripheral neuropathy (CIPN) is a dose limiting adverse effect of nab-paclitaxel. Ganglioside-Monosialic Acid (GM1) is an abundant glycosphingolipid in neuronal membranes and studies have shown its potential in preventing CIPN as a neuroprotective factor. This study was conducted to evaluate the effect of GM1 in preventing CIPN induced by nab-paclitaxel in breast cancer patients. Methods This study was a randomized, double-blind, placebo-controlled phase II trial conducted at three hospitals in China (NCT04222790). Female patients 18 to 75 years with early-stage breast cancer who were scheduled to receive nab-paclitaxel containing chemotherapy were randomly assigned to receive GM1 or placebo. Nab- paclitaxel was given 125-150 mg/m2 once per week for 12 cycles or 260 mg/m2 once every 3 weeks for four cycles. GM1 or placebo started one day before chemotherapy and was given once per day for 3 days (day −1, day 1, and day 2). The primary outcome was peripheral neuropathy evaluated by the Functional Assessment of Cancer Treatment Neurotoxicity (FACT-Ntx) subscale at 2 weeks after four cycles of chemotherapy. Other endpoints included peripheral neuropathy evaluated by CTCAE version 4.0, Functional Assessment of Cancer Therapy – General (FACT-G) scores and Functional Assessment of Cancer Therapy – Taxane (FACT-Taxane) scores at 2 weeks after four cycles of chemotherapy. Adverse events were evaluated by CTCAE version 4.0. Additional long-term assessments were performed at 3 months, 6 months, and 1 year after the completion of chemotherapy. All assessments were performed by trained physicians. Results 159 patients were enrolled from April 2020 to June 2021, with 79 patients assigned to the GM1 group and 80 patients to the placebo group. Eight patients in the GM1 group and eight patients in the placebo group did not complete the endpoint assessments. In total, 71 patients in GM1 group and 72 in placebo group were evaluated. Baseline characteristics were generally well balanced between groups. After four cycles of Nab-paclitaxel containing chemotherapy, Patients in the GM1 group reported similar mean FACT-Ntx subscale 36.1 (35.1-37.0) with patients in the placebo group 36.4 (35.3-37.3). Compared with baseline, the mean FACT-Ntx score at two weeks after four cycles of chemotherapy decreased by 7.9 in the GM1 group (p&amp;lt; 0.001) and 7.6 in the placebo group (p&amp;lt; 0.001). The difference between GM1 group and placebo group was not statistically significant (P=0.703). No difference was observed in secondary outcomes except that GM1 group showed lower FACT G scores (61.0, 95% CI, 58.1-63.9) than the control group (67.0, 95% CI, 63.2-70.8) at two weeks after four cycles of chemotherapy, the difference was statistically significant (P=0.014). The main results of primary and secondary outcomes were summarized in Table 1. Random assignment was stratified by age (&amp;lt; 60 or &amp;gt;=60) and BMI ((&amp;lt; 24 or &amp;gt;=24). Subgroup analysis was performed for patients in different age and BMI groups. Overall, patients above 60 years old showed lower FACT-Ntx score at than patients under 60 (34.1 and 36.5, respectively. P=0.056). Overweight patients (BMI &amp;gt;=24) showed similar FACT-Ntx score with patients with BMI smaller than 24 (36.8 and 35.7, respectively. P=0.095). The FACT-Ntx score was not significantly different between the GM1 and placebo group in different age and BMI subgroups. The most common adverse events, including myalgia-arthralgia, nausea, vomit, and diarrhea, were evaluated according to CTCAE version 4.0. Incidence and severity of adverse events were not statistically significantly different between the two groups. Conclusion GM1 did not prevent peripheral neuropathy induced by nab-paclitaxel in breast cancer patients. The effect of GM1 in preventing CIPN is still inconclusive and further studies are needed. Caution in recommending GM1 to prevent CIPN is clearly warranted. Table 1. FACT-Ntx subscale, CTCAE version 4.0, FACT-Taxane and FACT G at 2 weeks after four cycles chemotherapy. a. FACT-Ntx: Functional Assessment of Cancer Treatment- Neurotoxicity; b. CTCAE4.0: Common Terminology Criteria for Adverse Events; c. FACT-Taxane: Functional Assessment of Cancer Treatment – Taxane; d. FACT G: Functional Assessment of Cancer Treatment- General. Citation Format: Zhenduo Lu, Dechuang Jiao, Jianghua Qiao, Hao Zhang, Hao Dai, Xianfu Sun, Min Yan, Yong Zhou, Lianfang Li, Chengzheng Wang, Xiuchun Chen, Zhenzhen Liu. Ganglioside-Monosialic Acid for Prevention of Peripheral Neuropathy Induced by nab-Paclitaxel in Breast Cancer Patients (HELEN-004): A Randomized, Double-Blind, Phase II Trial [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO3-28-04.

Rhodamine B, an organic environmental pollutant induces reproductive toxicity in parental and teratogenicity in F1 generation in vivo

This study investigated the reproductive toxicity of rhodamine B in zebrafish and its transgenerational effects on the F1 generation. In silico toxicity predictions revealed high toxicity of rhodamine B, mainly targeting pathways associated with the reproductive and endocrine systems. In vivo experiments on zebrafish demonstrated that rhodamine B exposure at a concentration of 1.5 mg/L led to significant impairments in fecundity parameters, particularly affecting females. Histopathological analysis revealed distinct changes in reproductive organs, further confirming the reproductive toxicity of rhodamine B, with females being more susceptible than males. Gene expression studies indicated significant suppression of genes crucial for ovulation in rhodamine B-treated female fish, highlighting hormonal imbalance as a potential mechanism of reproductive toxicity. Furthermore, bioaccumulation studies showed the presence of rhodamine B in both adult fish gonads and F1 generation samples, suggesting transgenerational transfer of the dye. Embryotoxicity studies on F1 generation larvae demonstrated reduced survival rates, lower hatching rates, and increased malformations in groups exposed to rhodamine B. Moreover, rhodamine B induced oxidative stress in F1 generation larvae, as evidenced by elevated levels of reactive oxygen species and altered antioxidant enzyme activity. Neurotoxicity assessments revealed reduced acetylcholinesterase activity, indicating potential neurological impairments in F1 generation larvae. Additionally, locomotory defects and skeletal abnormalities were observed in F1 generation larvae exposed to rhodamine B. This study provides comprehensive evidence of the reproductive toxicity of rhodamine B in adult zebrafish and its transgenerational effects on the F1 generation.

Recent advances and current challenges of new approach methodologies in developmental and adult neurotoxicity testing.

Adult neurotoxicity (ANT) and developmental neurotoxicity (DNT) assessments aim to understand the adverse effects and underlying mechanisms of toxicants on the human nervous system. In recent years, there has been an increasing focus on the so-called new approach methodologies (NAMs). The Organization for Economic Co-operation and Development (OECD), together with European and American regulatory agencies, promote the use of validated alternative test systems, but to date, guidelines for regulatory DNT and ANT assessment rely primarily on classical animal testing. Alternative methods include both non-animal approaches and test systems on non-vertebrates (e.g., nematodes) or non-mammals (e.g., fish). Therefore, this review summarizes the recent advances of NAMs focusing on ANT and DNT and highlights the potential and current critical issues for the full implementation of these methods in the future. The status of the DNT in vitro battery (DNT IVB) is also reviewed as a first step of NAMs for the assessment of neurotoxicity in the regulatory context. Critical issues such as (i) the need for test batteries and method integration (from in silico and in vitro to in vivo alternatives, e.g., zebrafish, C. elegans) requiring interdisciplinarity to manage complexity, (ii) interlaboratory transferability, and (iii) the urgent need for method validation are discussed.