Caffeine-induced neurotoxicity mediated by Nrf2 pathway in PC12 cells and zebrafish larvae

Machine learning enables high-throughput, low-replicate screening for novel anti-seizure targets and compounds using combined movement and calcium fluorescence in larval zebrafish

Identifying new anti-seizure medications (ASMs) is difficult due to limitations in animal-based assays. Zebrafish (Danio rerio) serve as a model for chemical and genetic seizures, but current methods for detecting anti-seizure responses are limited by incomplete detection of anti-seizure responses (locomotor assays) or low-throughput (electrophysiology, fluorescence microscopy). To overcome these challenges, we developed a novel high-throughput method using combined locomotor and calcium fluorescence data from unrestrained larval zebrafish in a 96-well plate reader. Custom software tracked fish movement and fluorescence changes (deltaF/F0) from high-speed time-series, and logistic classifiers trained with elastic net regression distinguished seizure-like activity in response to the GABAA receptor antagonist pentylenetetrazole (PTZ). A classifier using combined data ("PTZ M + F"; AUC-ROC: 0.98; F1: 0.912) outperformed movement-only ("PTZ M"; AUC-ROC: 0.9) and fluorescence-only classifiers ("PTZ F"; AUC-ROC 0.96). Seizure-like event rate increased in proportion to PTZ concentration, and was suppressed by valproic acid (VPA). Meanwhile, TGB selectively reduced events defined by the "PTZ M + F″ classifier, paralleling previous reports that TGB reduces electrographic but not locomotor seizures. Using bootstrap simulation, we calculated statistical power and demonstrated reliable detection of ASM effects with as few as N = 4 replicates. In a test screen, 4 out of 5 ASMs were detected. This high-throughput approach combines previously orthogonal assays for zebrafish ASM screening.

Brain dysfunctions and neurotoxicity induced by psychostimulants in experimental models and humans: an overview of recent findings

Preclinical and clinical studies indicate that psychostimulants, in addition to having abuse potential, may elicit brain dysfunctions and/or neurotoxic effects. Central toxicity induced by psychostimulants may pose serious health risks since the recreational use of these substances is on the rise among young people and adults. The present review provides an overview of recent research, conducted between 2018 and 2023, focusing on brain dysfunctions and neurotoxic effects elicited in experimental models and humans by amphetamine, cocaine, methamphetamine, 3,4-methylenedioxymethamphetamine, methylphenidate, caffeine, and nicotine. Detailed elucidation of factors and mechanisms that underlie psychostimulant-induced brain dysfunction and neurotoxicity is crucial for understanding the acute and enduring noxious brain effects that may occur in individuals who use psychostimulants for recreational and/or therapeutic purposes.

Coffee and Alzheimer's disease

Coffee, a universally consumed beverage, is known to contain thousands of bioactive constituents that have garnered interest due to their potential neuroprotective effects against various neurodegenerative disorders, including Alzheimer's disease (AD). Extensive research has been conducted on coffee constituents such as Caffeine, Trigonelline, Chlorogenic acid, and Caffeic acid, focusing on their neuroprotective properties. These compounds have potential to impact key mechanisms in AD development, including amyloidopathy, tauopathy, and neuroinflammation. Furthermore, apart from its neuroprotective effects, coffee consumption has been associated with anticancerogenic and anti-inflammatory effects, thereby enhancing its therapeutic potential. Studies suggest that moderate coffee intake, typically around two to three cups daily, could potentially contribute to mitigating AD progression and lowering the risk of related neurological disorders. This literature underscores the potential neuroprotective properties of coffee compounds, which usually perform their neuronal protective effects via modulating nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), nuclear factor erythroid-derived 2-like 2 (Nrf2), interleukins, tumor necrosis factor-alpha (TNF-α), and many other molecules.

Temperature- and chemical-induced neurotoxicity in zebrafish

Throughout their lives, humans encounter a plethora of substances capable of inducing neurotoxic effects, including drugs, heavy metals and pesticides. Neurotoxicity manifests when exposure to these chemicals disrupts the normal functioning of the nervous system, and some neurotoxic agents have been linked to neurodegenerative pathologies such as Parkinson's and Alzheimer's disease. The growing concern surrounding the neurotoxic impacts of both naturally occurring and man-made toxic substances necessitates the identification of animal models for rapid testing across a wide spectrum of substances and concentrations, and the utilization of tools capable of detecting nervous system alterations spanning from the molecular level up to the behavioural one. Zebrafish (Danio rerio) is gaining prominence in the field of neuroscience due to its versatility. The possibility of analysing all developmental stages (embryo, larva and adult), applying the most common "omics" approaches (transcriptomics, proteomics, lipidomics, etc.) and conducting a wide range of behavioural tests makes zebrafish an excellent model for neurotoxicity studies. This review delves into the main experimental approaches adopted and the main markers analysed in neurotoxicity studies in zebrafish, showing that neurotoxic phenomena can be triggered not only by exposure to chemical substances but also by fluctuations in temperature. The findings presented here serve as a valuable resource for the study of neurotoxicity in zebrafish and define new scenarios in ecotoxicology suggesting that alterations in temperature can synergistically compound the neurotoxic effects of chemical substances, intensifying their detrimental impact on fish populations.

Caffeine Release from Magneto-Responsive Hydrogels Controlled by External Magnetic Field and Calcium Ions and Its Effect on the Viability of Neuronal Cells

Caffeine (CAF) is a psychostimulant present in many beverages and with rapid bioabsorption. For this reason, matrices that effectuate the sustained release of a low amount of CAF would help reduce the intake frequency and side effects caused by high doses of this stimulant. Thus, in this study, CAF was loaded into magnetic gelatin/alginate (Gel/Alg/MNP) hydrogels at 18.5 mg/ghydrogel. The in vitro release of CAF was evaluated in the absence and presence of an external magnetic field (EMF) and Ca2+. In all cases, the presence of Ca2+ (0.002 M) retarded the release of CAF due to favorable interactions between them. Remarkably, the release of CAF from Gel/Alg/MNP in PBS/CaCl2 (0.002 M) at 37 °C under an EMF was more sustained due to synergic effects. In PBS/CaCl2 (0.002 M) and at 37 °C, the amounts of CAF released after 45 min from Gel/Alg and Gel/Alg/MNP/EMF were 8.3 ± 0.2 mg/ghydrogel and 6.1 ± 0.8 mg/ghydrogel, respectively. The concentration of CAF released from Gel/Alg and Gel/Alg/MNP hydrogels amounted to ~0.35 mM, thereby promoting an increase in cell viability for 48 h. Gel/Alg and Gel/Alg/MNP hydrogels can be applied as reservoirs to release CAF at suitable concentrations, thus forestalling possible side effects and improving the viability of SH-SY5Y cells.

Therapy of traumatic brain injury by modern agents and traditional Chinese medicine

Traumatic brain injury (TBI) is the leading cause of disability and death, and the social burden of mortality and morbidity caused by TBI is significant. Under the influence of comprehensive factors, such as social environment, lifestyle, and employment type, the incidence of TBI continues to increase annually. Current pharmacotherapy of TBI mainly focuses on symptomatic supportive treatment, aiming to reduce intracranial pressure, ease pain, alleviate irritability, and fight infection. In this study, we summarized numerous studies covering the use of neuroprotective agents in different animal models and clinical trials after TBI. However, we found that no drug has been approved as specifically effective for the treatment of TBI. Effective therapeutic strategies for TBI remain an urgent need, and attention is turning toward traditional Chinese medicine. We analyzed the reasons why existing high-profile drugs had failed to show clinical benefits and offered our views on the research of traditional herbal medicine for treating TBI.

In vivo toxicity assessment of Remazol Gelb-GR (RG-GR) textile dye in zebrafish embryos/larvae (Danio rerio): Teratogenic effects, biochemical changes, immunohistochemical changes

Dyes, which are very important for various industries, have very adverse effects on the aquatic environment and aquatic life. However, there are limited studies on the toxic properties of dyes on living things. This research elucidated the sublethal toxicity of acute exposure of the textile dye remazol gelb-GR (RG-GR) using zebrafish embryos and larvae for 96 h. The 96 h-LC₅₀ for RG-GR in zebrafish embryos/larvae was determined to be 151.92 mg/L. Sublethal 96 hpf exposure was performed in RG-GR concentrations (0.5; 1.0; 10.0; 100.0 mg/L) to determine the development of toxicity in zebrafish embryos/larvae. RG-GR dye affected morphological development, and decreased heart rate, hatching, blood flow, and survival rates in zebrafish embryos/larvae. The immunopositivity of 8-hydroxy 2 deoxyguanosine (8-OHdG) in larvae exposed to RG-GR at high concentrations was found to be intense. Depending on the RG-GR dose increase, some biochemical parameters such as glutathione peroxidase (GSH) level, acetylcholinesterase (AChE) activity, catalase (CAT) activities, superoxide dismutase (SOD), and nuclear factor erythroid 2 (Nrf-2) levels were detected to be decreased in larvae, while malondialdehyde (MDA) content, nuclear factor kappa (NF-kB), tumor necrosis factor-α (TNF-α), DNA damage (8-OHdG level), interleukin-6 (IL-6) and apoptosis (Caspase-3) levels were found to be increased. The experimental results revealed that RG-GR dye has high acute toxicity on zebrafish embryo/larvae.