Ex Vivo and In Silico Approaches of Tracheal Relaxation through Calcium Channel Blockade of 6-Aminoflavone and Its Toxicological Studies in Murine Models

Asthma is a condition in which a person's airways become inflamed, narrowed, and produce greater amounts of mucus than normal. It can cause shortness of breath, chest pain, coughing, or wheezing. In some cases, symptoms may be exacerbated. Thus, the current study was designed to determine the mechanism of action of 6-aminoflavone (6-NH₂F) in ex vivo experiments, as well as to determine its toxicity in acute and sub-chronic murine models. Tissues were pre-incubated with 6-NH₂F, and concentration-response curves to carbachol-induced contraction were constructed. Therefore, tracheal rings pre-treated with glibenclamide, 2-aminopyridine, or isoproterenol were contracted with carbachol (1 µM), then 6-NH₂F relaxation curves were obtained. In other sets of experiments, to explore the calcium channel role in the 6-NH₂F relaxant action, tissues were contracted with KCl (80 mM), and 6-NH₂F was cumulatively added to induce relaxation. On the other hand, tissues were pre-incubated with the test sample, and after that, CaCl₂ concentration-response curves were developed. In this context, 6-NH₂F induced significant relaxation in ex vivo assays, and the effect showed a non-competitive antagonism pattern. In addition, 6-NH₂F significantly relaxed the contraction induced by KCl and CaCl₂, suggesting a potential calcium channel blockade, which was corroborated by in silico molecular docking that was used to approximate the mode of interaction with the L-type Ca²⁺ channel, where 6-NH₂F showed lower affinity energy when compared with nifedipine. Finally, toxicological studies revealed that 6-NH₂F possesses pharmacological safety, since it did not produce any toxic effect in both acute and sub-acute murine models. In conclusion, 6-aminoflavone exerted significant relaxation through calcium channel blockade, and the compound seems to be safe.

Phytochemical Analysis and Toxicity Assessment of Bouea Macrophylla Yoghurt

The Bouea macrophylla fruit is native to Malaysia and is known for its many beneficial effects on one's health. Probiotics are well-known for their roles as anti-inflammatory, antioxidant, and anti-tumour properties due to their widespread use. As a result, the purpose of this study was to incorporate the ethanolic extract of Bouea macrophylla into yoghurt and then assess the rodents for any toxicological effects. According to the findings of the nutritional analysis, each 100 mL serving of the newly formulated yoghurt contains 3.29 g of fat, 5.79 g of carbohydrates, 2.92 g of total protein, and 2.72 g of sugar. The ability of the newly developed yoghurt to stimulate the growth of Lactobacilli was demonstrated by the fact that the peak intensity of Lactobacillus species was measured at 1.2 × 10⁶ CFU/g while the titratable acidity of the lactic acid was measured at 0.599 CFU/g. In order to carry out the toxicological evaluation, forty-eight male Sprague Dawley (SD) rats were utilized. Oral administration of single doses of 2000 mg/kg over the course of 14 days was used for the study of acute toxicity. Subacute toxicity was studied by giving animals Bouea macrophylla yoghurt (BMY) at repeated doses of 50, 250, 500, and 1000 mg/kg/day over a period of 28 days, while the control group was given normal saline. The results of the acute toxicity test revealed that rats treated with increasing doses up to a maximum of 2000 mg/kg exhibited no signs of toxicity. After an additional 14 days without treatment, acute toxicity of a single dose (2000 mg/kg) of BMY did not show any treatment-related toxicity in any of the rats that were observed. According to the data from the subacute toxicity study, there were no differences between the treated groups and the control groups in terms of food and water intake, body weight, plasma biochemistry (AST, ALT, ALP, and creatinine), haematological products, or organ weights. The architecture of the liver, heart, and kidney were all found to be normal upon histological examination. This indicates that oral consumption of BMY did not result in any negative effects being manifested in the rodents.

Systemic Biomarkers and Liver Morphology in Rats during Chronic Low-Dose Toxicant Administration against the Background of Vitamin Deficiency

Liver morphology, intensity of apoptosis, and activity of xenobiotic metabolism enzymes were studied in a chronic model experiment in rats receiving a mixture of 6 pesticides against the background of life-long diets with adequate and insufficient supply of water-soluble vitamins. The dose of each pesticide in the mixture did not exceed the acceptable daily intake (1 ADI). It was found that chronic exposure to low doses of anthropogenic toxicants in combination with permanent vitamin deficiency provokes a number of liver changes, such as increased apoptosis activity, cytochrome P450 system depletion, steatosis, and inflammatory infiltration, which is a potential health risk factor.

The Ascension of Nanosponges as a Drug Delivery Carrier: Preparation, Characterization and Applications

Nanosponges are drug carriers that are nanoscale in size and have a three-dimensional structure generated by crosslinking polymers. They have the benefit of being able to carry a variety of medications of varied sizes. Nanosponges are available in a wide range of shapes and sizes. The study method, the type of polymer employed, and the sort of medicine they may include are all distinguishing factors. Nanosponges outperform conventional drug delivery methods by allowing for a regulated drug release pattern and targeted medication delivery. The duration of action and the duration of the drug's stay in the body can both be controlled. It has minimal toxicity and is safe to use because it is constructed of biodegradable components. The size of the drug molecule and the amount of space available determine the efficacy of drug encapsulation. Nanosponges have multiple uses in various fields and are not just limited to the field of drug delivery. This paper highlights the method to prepare nanosponges, the evaluation parameters, and the factors which affect the development of nanosponges.

Experimental Models for Testing the Efficacy of Pharmacological Treatments for Neonatal Hypoxic-Ischemic Encephalopathy

Representing an important cause of long-term disability, term neonatal hypoxic-ischemic encephalopathy (HIE) urgently needs further research aimed at repurposing existing drug as well as developing new therapeutics. Since various experimental in vitro and in vivo models of HIE have been developed with distinct characteristics, it becomes important to select the appropriate preclinical screening cascade for testing the efficacy of novel pharmacological treatments. As therapeutic hypothermia is already a routine therapy for neonatal encephalopathy, it is essential that hypothermia be administered to the experimental model selected to allow translational testing of novel or repurposed drugs on top of the standard of care. Moreover, a translational approach requires that therapeutic interventions must be initiated after the induction of the insult, and the time window for intervention should be evaluated to translate to real world clinical practice. Hippocampal organotypic slice cultures, in particular, are an invaluable intermediate between simpler cell lines and in vivo models, as they largely maintain structural complexity of the original tissue and can be subjected to transient oxygen-glucose deprivation (OGD) and subsequent reoxygenation to simulate ischemic neuronal injury and reperfusion. Progressing to in vivo models, generally, rodent (mouse and rat) models could offer more flexibility and be more cost-effective for testing the efficacy of pharmacological agents with a dose-response approach. Large animal models, including piglets, sheep, and non-human primates, may be utilized as a third step for more focused and accurate translational studies, including also pharmacokinetic and safety pharmacology assessments. Thus, a preclinical proof of concept of efficacy of an emerging pharmacological treatment should be obtained firstly in vitro, including organotypic models, and, subsequently, in at least two different animal models, also in combination with hypothermia, before initiating clinical trials.

Systematic review in evidence-based risk assessment

Systematic reviews provide a structured framework for summarizing the available evidence in a comprehensive, objective, and transparent manner. They inform evidence-based guidelines in medicine, public policy, and more recently, in environmental health and toxicology. Many regulatory agencies have extended and adapted the well-established systematic review methods, initially developed for clinical studies, for their assessment needs. The use of systematic reviews to summarize evidence from existing human, animal, and mechanistic studies can reduce reliance on animal test data in risk assessment and can help avoid unnecessary duplication of animal experiments that have already been conducted. As alternative test methods can be expected to play an increasing role in human health risk assessment in the future, systematic reviews can be particularly helpful in validating these alternatives. The field of evidence-based toxicology has undergone extensive development since its first meeting in 2007 as a result of collaborative efforts among international experts and public health agencies, particularly with respect to the use of mechanistic data and evidence integration. The continued development and wider adoption of systematic review methodology can lead to better 3R implementation. As undertaking a systematic review can be a complex and lengthy process, it is important to understand the main steps involved. Key steps, along with current best practices, are described with references to guidance from organizations with expertise in evidence synthesis. Applications of systematic reviews in clinical, observational, and experimental studies are presented. Finally, software tools available to facilitate and increase the efficiency of completing a systematic review are described.

Toxicological Evaluation of Piceatannol, Pterostilbene, and ε-Viniferin for Their Potential Use in the Food Industry: A Review

The application of stilbenes in the food industry is being considered because of their biological activities. Piceatannol, pterostilbene and ε-viniferin have awakened the industry’s interest. However, before they can be commercialized, we must first guarantee their safety for consumers. The present work reviews the toxicological studies performed with these stilbenes. A wide variety of studies has demonstrated their cytotoxic effects in both cancer and non-cancerous cell lines. In contrast, although DNA damage was detected by some authors, in vitro genotoxic studies on the effects of piceatannol, pterostilbene, and ε-viniferin remain scarce. None of the three reviewed substances have been evaluated using the in vitro tests required by the European Food Safety Authority (EFSA) as the first step in genotoxicity testing. We did not find any study on the toxic effects of these stilbenes in vivo. Thus, more studies are needed to confirm their safe use before they can be authorized as additive in the food industry.

Interaction of Environmental Pollutants with Microplastics: A Critical Review of Sorption Factors, Bioaccumulation and Ecotoxicological Effects

Microplastics have become one of the leading environmental threats due to their persistence, ubiquity and intrinsic toxic potential. The potential harm that microplastics impose on ecosystems varies from direct effects (i.e., entanglement and ingestion) to their ability to sorb a diversity of environmental pollutants (e.g., heavy metals, persistent organic compounds or pharmaceuticals). Therefore, the toxicological assessment of the combined effects of microplastics and sorbed pollutants can produce in biota is one of the hottest topics on the environmental toxicology field. This review aims to clarify the main impacts that this interaction could have on ecosystems by (1) highlighting the principal factors that influence the microplastics sorption capacities; (2) discussing the potential scenarios in which microplastics may have an essential role on the bioaccumulation and transfer of chemicals; and (3) reviewing the recently published studies describing toxicological effects caused by the combination of microplastics and their sorbed chemicals. Finally, a discussion regarding the need for a new generation of toxicological studies is presented.

Quaternary Ammonium Leucine-Based Surfactants: The Effect of a Benzyl Group on Physicochemical Properties and Antimicrobial Activity

Quaternary ammonium amphiphiles are a class of compounds with a wide range of commercial and industrial uses. In the pharmaceutical field, the most common quaternary ammonium surfactant is benzalkonium chloride (BAC), which is employed as a preservative in several topical formulations for ocular, skin, or nasal application. Despite the broad antimicrobial activity against Gram-positive and Gram-negative bacteria, as well as fungi and small enveloped viruses, safety concerns regarding its irritant and cytotoxic effect on epithelial cells still remain. In this work, quaternary ammonium derivatives of leucine esters (C10, C12 and C14) were synthesised as BAC analogues. These cationic surfactants were characterised in terms of critical micelle concentration (CMC, by tensiometry), cytotoxicity (MTS and LDH assays on the Caco-2 and Calu-3 cell lines) and antimicrobial activity on the bacterial species Staphylococcus aureus and Enterococcus faecalis among the Gram-positives, Escherichia coli and Pseudomonas aeruginosa among the Gram-negatives and the yeast Candida albicans. They showed satisfactory surface-active properties, and a cytotoxic effect that was dependent on the length of the hydrophobic chain. Lower minimum inhibiting concentration (MIC) values were calculated for C14-derivatives, which were comparable to those calculated for BAC toward Gram-positive bacteria and slightly higher for Gram-negative bacteria and C. albicans. Thus, the synthesised leucine-based quaternary ammonium cationic surfactants can potentially find application as promising surface-active compounds with antimicrobial activity.

Analysis of the Intensity of Apoptosis in Rat Organs at Various Stages of Ontogeny

Activity of apoptosis in the thymus, liver, and kidneys on days 20, 22, 35, 50, 80, 110, and 140 of ontogeny was studied in the experiments on rats using the alkaline gel electrophoresis and flow cytofluorometry. Changes in apoptosis intensity depended on animal age. The maximum level of this parameter was observed on day 20 of ontogeny with the following reduction in this parameter to the minimum value on days 35-50. Then it gradually increased up to relatively high levels on day 110 and significantly reduced by day 140.

Preclinical Toxicological Study of Release-Active Preparations for Prediction of Their Pharmacological Activity and Side Effects

We studied chronic toxicity of a few release-active preparations: Dietressa (release-active preparation of affinity-purified antibodies to type 1 cannabinoid receptor), Divasa (releaseactive preparation containing a combination of affinity-purified antibodies to brain-specific S-100 protein and endothelial NO-synthase), Cardostin (release-active preparation containing a combination of affinity-purified antibodies to C-terminal fragment of angiotensin II type 1 receptor and endothelial NO-synthase), and Bation (release-active preparation containing a combination of affinity-purified antibodies to IFN-γ and CD4). We evaluated not only side and toxic effects, but also the relationships between these effects and pharmacological activities of the preparations. The data of preclinical toxicological studies of the release-active preparations can be used for prediction of their pharmacological activity.

Tumor Selectivity of Oncolytic Parvoviruses: From in vitro and Animal Models to Cancer Patients

Oncolytic virotherapy of cancer is among the innovative modalities being under development and especially promising for targeting tumors, which are resistant to conventional treatments. Presently, at least a dozen of viruses, belonging to nine different virus families, are being tested within the frames of various clinical studies in cancer patients. Continuously growing preclinical evidence showing that the autonomous rat parvovirus H-1 (H-1PV) is able to kill tumor cells that resist conventional treatments and to achieve a complete cure of various human tumors in animal models argues for its inclusion in the arsenal of oncolytic viruses with an especially promising bench to bedside translation potential. Oncolytic parvovirus safe administration to humans relies on the intrinsic preference of these agents for quickly proliferating, metabolically, and biochemically disturbed tumor versus normal cells (tumor selectivity or oncotropism). The present review summarizes and discusses (i) preclinical evidence of H-1PV innocuousness for normal cells and healthy tissues in vitro and in animals, respectively, (ii) toxicological assessments of H-1PV mono- or combined therapy in tumor-bearing virus-permissive animal models, as well as (iii) historical results of experimental infection of human cancer patients with H-1PV. Altogether, these data argue against a risk of H-1PV inducing significant toxic effects in human patients. This highly favorable safety profile allowed the translation of H-1PV preclinical research into a Phase I/IIa clinical trial being currently in progress.