3Rs Principle and Legislative Decrees to Achieve High Standard of Animal Research

Drug-induced torsadogenicity prediction model: An explainable machine learning-driven quantitative structure-toxicity relationship approach

Drug-induced Torsade de Pointes (TdP), a life-threatening polymorphic ventricular tachyarrhythmia, emerges due to the cardiotoxic effects of pharmaceuticals. The need for precise mechanisms and clinical biomarkers to detect this adverse effect presents substantial challenges in drug safety assessment. In this study, we propose that analyzing the physicochemical properties of pharmaceuticals can provide valuable insights into their potential for torsadogenic cardiotoxicity. Our research centers on estimating TdP risk based on the molecular structure of drugs. We introduce a novel quantitative structure-toxicity relationship (QSTR) prediction model that leverages an in silico approach developed by adopting the 4R rule in laboratory animals. This approach eliminates the need for animal testing, saves time, and reduces cost. Our algorithm has successfully predicted the torsadogenic risks of various pharmaceutical compounds. To develop this model, we employed Support Vector Machine (SVM) and ensemble techniques, including Random Forest (RF), Extreme Gradient Boosting (XGBoost), and Categorical Boosting (CatBoost). We enhanced the model's predictive accuracy through a rigorous two-step feature selection process. Furthermore, we utilized the SHapley Additive exPlanations (SHAP) technique to explain the prediction of torsadogenic risk, particularly within the RF model. This study represents a significant step towards creating a robust QSTR model, which can serve as an early screening tool for assessing the torsadogenic potential of pharmaceutical candidates or existing drugs. By incorporating molecular structure-based insights, we aim to enhance drug safety evaluation and minimize the risks of drug-induced TdP, ultimately benefiting both patients and the pharmaceutical industry.

Graph neural networks-enhanced relation prediction for ecotoxicology (GRAPE)

Exposure to toxic chemicals threatens species and ecosystems. This study introduces a novel approach using Graph Neural Networks (GNNs) to integrate aquatic toxicity data, providing an alternative to complement traditional in vivo ecotoxicity testing. This study pioneers the application of GNN in ecotoxicology by formulating the problem as a relation prediction task. GRAPE's key innovation lies in simultaneously modelling 444 aquatic species and 2826 chemicals within a graph, leveraging relations from existing datasets where informative species and chemical features are augmented to make informed predictions. Extensive evaluations demonstrate the superiority of GRAPE over Logistic Regression (LR) and Multi-Layer Perceptron (MLP) models, achieving remarkable improvements of up to a 30% increase in recall values. GRAPE consistently outperforms LR and MLP in predicting novel chemicals and new species. In particular, GRAPE showcases substantial enhancements in recall values, with improvements of ≥ 100% for novel chemicals and up to 13% for new species. Specifically, GRAPE correctly predicts the effects of novel chemicals (104 out of 126) and effects on new species (7 out of 8). Moreover, the study highlights the effectiveness of the proposed chemical features and induced network topology through GNN for accurately predicting metallic (74 out of 86) and organic (612 out of 674) chemicals, showcasing the broad applicability and robustness of the GRAPE model in ecotoxicological investigations. The code/data are provided at https://github.com/csiro-robotics/GRAPE.

Efficiency of cavitary varnishes containing experimental bioglass particles in the occlusion of dentinal tubules

This research aims to evaluate the efficiency of cavitary varnishes containing experimental bioglasses in the occlusion of dentinal tubules. One hundred and sixty-eight cervical buccal dentin samples were obtained from bovine teeth. Samples were randomized into the following groups: I. Distilled Water (DW); II. Cavity Varnish (CV); III. Colgate® Sensitive Pro-Relief™ (CS); IV. 45S5 Bioglass (45S5); V. KSr Bioglass strontium potassium (KSr); VI. P Bioglass phosphorus (P); and VII. PSi Bioglass phosphorus silica (PSi). The treatments were applied to the surfaces of the samples, which were then subjected to simulated brushing. The samples were analyzed for a) characterization of bioactive glasses; b) surface roughness; c) descriptive analysis of the dentin surface; d) total versus occluded number of dentinal tubules; e) diameter of the dentinal tubules; f) chemical composition of the dentin surfaces, and g) dentin permeability. All groups treated with biomaterials without the brushing challenge showed an increase in roughness and (total or partial) occlusion of the dentinal tubules. The PSi group had the best values for occlusion, while the KSr group had the highest calcium and phosphorus concentrations. After the brushing challenge the roughness was controlled by the presence of biomaterials; 45S5, KSr, and PSi showed occlusion of the dentin tubules. All bioactive glasses showed reduced tooth permeability compared to distilled water. The PSi group had the smallest tubule diameter and highest phosphorus concentration. KSr and PSi bioglasses are promising materials for dentin occlusion and remineralization and are promising new biomaterials for the treatment of dentin hypersensitivity.

Transcriptomic signature, bioactivity and safety of a non-hepatotoxic analgesic generating AM404 in the midbrain PAG region

Safe and effective pain management is a critical healthcare and societal need. The potential for acute liver injury from paracetamol (ApAP) overdose; nephrotoxicity and gastrointestinal damage from chronic non-steroidal anti-inflammatory drug (NSAID) use; and opioids' addiction are unresolved challenges. We developed SRP-001, a non-opioid and non-hepatotoxic small molecule that, unlike ApAP, does not produce the hepatotoxic metabolite N-acetyl-p-benzoquinone-imine (NAPQI) and preserves hepatic tight junction integrity at high doses. CD-1 mice exposed to SRP-001 showed no mortality, unlike a 70% mortality observed with increasing equimolar doses of ApAP within 72 h. SRP-001 and ApAP have comparable antinociceptive effects, including the complete Freund's adjuvant-induced inflammatory von Frey model. Both induce analgesia via N-arachidonoylphenolamine (AM404) formation in the midbrain periaqueductal grey (PAG) nociception region, with SRP-001 generating higher amounts of AM404 than ApAP. Single-cell transcriptomics of PAG uncovered that SRP-001 and ApAP also share modulation of pain-related gene expression and cell signaling pathways/networks, including endocannabinoid signaling, genes pertaining to mechanical nociception, and fatty acid amide hydrolase (FAAH). Both regulate the expression of key genes encoding FAAH, 2-arachidonoylglycerol (2-AG), cannabinoid receptor 1 (CNR1), CNR2, transient receptor potential vanilloid type 4 (TRPV4), and voltage-gated Ca2+ channel. Phase 1 trial (NCT05484414) (02/08/2022) demonstrates SRP-001's safety, tolerability, and favorable pharmacokinetics, including a half-life from 4.9 to 9.8 h. Given its non-hepatotoxicity and clinically validated analgesic mechanisms, SRP-001 offers a promising alternative to ApAP, NSAIDs, and opioids for safer pain treatment.

Aged and induced-premature ovarian failure mouse models affect diestrus profile and ovarian features

Sex hormones exert a wide influence on several systems of the human body, especially in women, who undergo intense changes in the trans and postmenopausal periods. Different experimental models are used to mimic these conditions; however, the impact on hormonal profile may be different. This study aimed to analyze and compare vaginal cytology of different post-estropausal mice models, along with their microscopical ovarian features. Forty-six C57BL/6J female mice with the ages of 4, 6 and 18 months at the beginning of the experiment, weighing about 25-28 grams, constituted five groups: NC-(negative control) animals with no treatment, OVX-SHAM-sham ovariectomized, OVX-ovariectomized, VCD-medicated with 160 mg/kg/day of 4-vinylcyclohexene diepoxide via IP for 20 consecutive days, and Aged-senescent mice under physiological estropause. Euthanasia was performed at different periods for the removal of the ovaries, and after diestrus was confirmed by vaginal cytology for 10 consecutive days. For daily vaginal cytology, morphological and histomorphometric microscopic analyzes were performed. Aged mice presented significant increased neutrophils when compared to VCD group, as well as increased cornified epithelial cells when compared to OVX mice, and also increased nucleated epithelial cells when compared to VCD and OVX. NC and OVX-SHAM ovaries presented innumerous follicles at different stages of development, while VCD showed marked follicular atresia, depleted of primordial or developing follicles and a predominance of interstitial cells. The ovaries of aged mice were predominantly constituted by corpus luteum degenerated into corpus albicans, with rare antral follicles. All analyzed models led to different permanent diestrus profiles caused by each model, as indicated by ovarian features. This should be carefully considered when choosing a post-estropausal experimental model, in order to better correlate this challenging phase of female's life with physiological/pathological conditions.

Development of ARPE-19-Equipped Ocular Cell Model for In Vitro Investigation on Ophthalmic Formulations

Repeated intravitreal (IVT) injections in the treatment of retinal diseases can lead to severe complications. Developing innovative drug delivery systems for IVT administration is crucial to prevent adverse reactions, but requires extensive investigation including the use of different preclinical models (in vitro, ex vivo and in vivo). Our previous work described an in vitro tricompartmental ocular flow cell (TOFC) simulating the anterior and posterior cavities of the human eye. Based on promising preliminary results, in this study, a collagen scaffold enriched with human retinal pigmented epithelial cells (ARPE-19) was developed and introduced into the TOFC to partially mimic the human retina. Cells were cultured under dynamic flow conditions to emulate the posterior segment of the human eye. Bevacizumab was then injected into the central compartment of the TOFC to treat ARPE-19 cells and assess its effects. The results showed an absence of cytotoxic activity and a significant reduction in VEGF fluorescent signal, underscoring the potential of this in vitro model as a platform for researching new ophthalmic formulations addressing the posterior eye segment, eventually decreasing the need for animal testing.

Progress towards the Replacement of the Rabbit Blood Sugar Test for the Quantitative Determination of the Biological Activity of Insulins (USP <121>) with an In Vitro Assay

For the quantification of insulin activity, United States Pharmacopeia (USP) general chapter <121> continues to require the rabbit blood sugar test. For new insulin or insulin analogue compounds, those quantitative data are expected for stability or comparability studies. At Sanofi, many rabbits were used to fulfil the authority's requirements to obtain quantitative insulin bioactivity data until the in vivo test was replaced. In order to demonstrate comparability between the in vivo and in vitro test systems, this study was designed to demonstrate equivalency. The measurement of insulin lispro and insulin glargine drug substance and drug product batches, including stress samples (diluted or after temperature stress of 30 min at 80 °C), revealed a clear correlation between the in vitro and in vivo test results. The recovery of quantitative in vitro in-cell Western (ICW) results compared to the in vivo test results was within the predefined acceptance limits of 80% to 125%. Thus, the in vitro ICW cell-based bioassay leads to results that are equivalent to the rabbit blood sugar test per USP <121>, and it is highly suitable for insulin activity quantification. For future development compounds, the in vitro in-cell Western cell-based assay can replace the rabbit blood sugar test required by USP <121>.

The 3Rs in Experimental Liver Disease

Patients with cirrhosis present multiple physiological and immunological alterations that play a very important role in the development of clinically relevant secondary complications to the disease. Experimentation in animal models is essential to understand the pathogenesis of human diseases and, considering the high prevalence of liver disease worldwide, to understand the pathophysiology of disease progression and the molecular pathways involved, due to the complexity of the liver as an organ and its relationship with the rest of the organism. However, today there is a growing awareness about the sensitivity and suffering of animals, causing opposition to animal research among a minority in society and some scientists, but also about the attention to the welfare of laboratory animals since this has been built into regulations in most nations that conduct animal research. In 1959, Russell and Burch published the book "The Principles of Humane Experimental Technique", proposing that in those experiments where animals were necessary, everything possible should be done to try to replace them with non-sentient alternatives, to reduce to a minimum their number, and to refine experiments that are essential so that they caused the least amount of pain and distress. In this review, a comprehensive summary of the most widely used techniques to replace, reduce, and refine in experimental liver research is offered, to assess the advantages and weaknesses of available experimental liver disease models for researchers who are planning to perform animal studies in the near future.

State-of-the-Art in the Drug Discovery Pathway for Chagas Disease: A Framework for Drug Development and Target Validation

Chagas disease is the most important protozoan infection in the Americas, and constitutes a significant public health concern throughout the world. Development of new medications against its etiologic agent, Trypanosoma cruzi, has been traditionally slow and difficult, lagging in comparison with diseases caused by other kinetoplastid parasites. Among the factors that explain this are the incompletely understood mechanisms of pathogenesis of T. cruzi infection and its complex set of interactions with the host in the chronic stage of the disease. These demand the performance of a variety of in vitro and in vivo assays as part of any drug development effort. In this review, we discuss recent breakthroughs in the understanding of the parasite's life cycle and their implications in the search for new chemotherapeutics. For this, we present a framework to guide drug discovery efforts against Chagas disease, considering state-of-the-art preclinical models and recently developed tools for the identification and validation of molecular targets.

Ex Vivo Osteogenesis Induced by Calcium Silicate-Based Cement Extracts

Calcium silicate-based cements are used in a variety of clinical conditions affecting the pulp tissue, relying on their inductive effect on tissue mineralization. This work aimed to evaluate the biological response of calcium silicate-based cements with distinct properties-the fast-setting Biodentine™ and TotalFill^® BC RRM™ Fast Putty, and the classical slow-setting ProRoot^® MTA, in an ex vivo model of bone development. Briefly, eleven-day-old embryonic chick femurs were cultured for 10 days in organotypic conditions, being exposed to the set cements' eluates and, at the end of the culture period, evaluated for osteogenesis/bone formation by combining microtomographic analysis and histological histomorphometric assessment. ProRoot^® MTA and TotalFill^® extracts presented similar levels of calcium ions, although significantly lower than those released from Biodentine^TM. All extracts increased the osteogenesis/tissue mineralization, assayed by microtomographic (BV/TV) and histomorphometric (% of mineralized area; % of total collagen area, and % of mature collagen area) indexes, although displaying distinct dose-dependent patterns and quantitative values. The fast-setting cements displayed better performance than that of ProRoot^® MTA, with Biodentine^TM presenting the best performance, within the assayed experimental model.

Grain-sized moxibustion at Zusanli (ST36) promotes hepatic autophagy in rats with hyperlipidemia by regulating the ULK1 and TFEB expression through the AMPK/mTOR signaling pathway

Objective

Grain-sized moxibustion is an effective treatment for hyperlipidemia, but how it regulates dyslipidemia and liver lipid deposits still needs to be fully understood. This study explored the molecular biological mechanism of grain-sized moxibustion to regulate hepatic autophagy in hyperlipidemic rats by affecting ULK1 and TFEB through the AMPK/mTOR signaling pathway.

Methods

Thirty male Sprague-Dawley (SD) rats were fed a high-fat diet for eight weeks to induce hyperlipidemia. Hyperlipidemic rats were divided into the HFD group, HFD + Statin group, HFD + CC + Moxi group, and grain-sized moxibustion intervention group (HFD + Moxi group). The control (Blank) group consisted of normal rats without any intervention. Grain-sized moxibustion and drug interventions were initiated eight weeks after high-fat diet induction and continued for ten weeks. Serum total cholesterol (TC), triglyceride (TG), low-density lipoprotein (LDL), and high-density lipoprotein (HDL), as well as hepatic triglyceride (TG), were measured after treatment. Hepatic steatosis and the expression of LC3I, LC3II, p62, p-AMPK, AMPK, p-mTOR, mTOR, ULK1, p-ULK1, and TFEB in the liver were analyzed.

Results

Compared with the HFD group, grain-sized moxibustion improved hyperlipidemia and hepatocyte steatosis, increased the LC3, p-AMPK, p-ULK1, and nuclear TFEB expression in the liver, but decreased the p62 and p-mTOR expression.

Conclusion

Grain-sized moxibustion at ST36 acupoints could regulate the blood lipid level of SD rats with hyperlipidemia, increase the expression level of ULK1 and TFEB by activating the AMPK/mTOR signaling pathway in liver tissues, and initiate the transcription of autophagy genes such as LC3.