The 3Rs and Humane Experimental Technique: Implementing Change

In silico assessment of nanoparticle toxicity powered by the Enalos Cloud Platform: Integrating automated machine learning and synthetic data for enhanced nanosafety evaluation

The rapid advance of nanotechnology has led to the development and widespread application of nanomaterials, raising concerns regarding their potential adverse effects on human health and the environment. Traditional (experimental) methods for assessing the nanoparticles (NPs) safety are time-consuming, expensive, and resource-intensive, and raise ethical concerns due to their reliance on animals. To address these challenges, we propose an in silico workflow that serves as an alternative or complementary approach to conventional hazard and risk assessment strategies, which incorporates state-of-the-art computational methodologies. In this study we present an automated machine learning (autoML) scheme that employs dose-response toxicity data for silver (Ag), titanium dioxide (TiO2), and copper oxide (CuO) NPs. This model is further enriched with atomistic descriptors to capture the NPs' underlying structural properties. To overcome the issue of limited data availability, synthetic data generation techniques are used. These techniques help in broadening the dataset, thus improving the representation of different NP classes. A key aspect of this approach is a novel three-step applicability domain method (which includes the development of a local similarity approach) that enhances user confidence in the results by evaluating the prediction's reliability. We anticipate that this approach will significantly expedite the nanosafety assessment process enabling regulation to keep pace with innovation, and will provide valuable insights for the design and development of safe and sustainable NPs. The ML model developed in this study is made available to the scientific community as an easy-to-use web-service through the Enalos Cloud Platform (www.enaloscloud.novamechanics.com/sabydoma/safenanoscope/), facilitating broader access and collaborative advancements in nanosafety.

Ecotoxicological evaluation of an aqueous phytoextract of Melia azedarach L

Melia azedarach L. is a Meliaceae that has shown important insecticidal activities. However, few researchers have extensively studied the toxicology of aqueous extracts of M. azedarach (MAE). Therefore, the main objective of this study was to characterize the phyto-eco-toxicological profile of MAE. First, a botanical and phytochemical characterization of MAE was performed using a histological, and metabolomic multi-analytical approach. Second, the toxicological effects on pollinating insects (Apis mellifera ligustica) and soil collembola (Folsomia candida) were evaluated. In addition, acute toxicity was evaluated in zebrafish (Danio rerio) to assess effects on aquatic fauna, and toxicity was determined in human neuroblastoma (SH-SY5Y) and fibroblast (FB-21) cell models. Finally, phytotoxic effects on germination of Cucumis sativus L., Brassica rapa L. and Sorghum vulgare L. were considered. Metabolomic analyses revealed the presence of not only limonoids but also numerous alkaloids, flavonoids and terpenoids in MAE. Histological analyses allowed us to better localize the areas of leaf deposition of the identified secondary metabolites. Regarding the ecotoxicological data, no significant toxicity was observed in bees and collembola at all doses tested. In contrast, severe cardiac abnormalities were observed in zebrafish embryos at concentrations as low as 25 μg/mL. In addition, MAE showed toxicity at 1.6 μg/mL and 6.25 μg/mL in FB-21 and SH-SY5Y cells, respectively. Finally, MAE inhibited seed germination with inhibitory concentrations starting from 5.50 μg/mL in B. rapa, 20 μg/mL in S. vulgare, and 31 μg/mL in C. sativus. Although M. azedarach extracts are considered valuable natural insecticides, their ecological impact cannot be underestimated. Even the use of an environmentally friendly solvent (an aqueous solution), for the first time, is not without side effects. Therefore, the data collected in this study show the importance of evaluating the dosages, modes of administration and production methods of M. azedarach phytoextracts in agricultural settings.

Electroporation enhances cell death in 3D scaffold-based MDA-MB-231 cells treated with metformin

Triple-negative breast cancer (TNBC), the most aggressive subtype of breast cancer lacks estrogen, progesterone, and HER2 receptors and hence, is therapeutically challenging. Towards this, we studied an alternate therapy by repurposing metformin (FDA-approved type-2 diabetic drug with anticancer properties) in a 3D-scaffold culture, with electrical pulses. 3D cell culture was used to simulate the tumor microenvironment more closely and MDA-MB-231, human TNBC cells, treated with both 5 mM metformin (Met) and 8 electrical pulses at 2500 V/cm, 10 µs (EP1) and 800 V/cm, 100 µs (EP2) at 1 Hz were studied in 3D and 2D. They were characterized using cell viability, reactive oxygen species (ROS), glucose uptake, and lactate production assays at 24 h. Cell viability, as low as 20 % was obtained with EP1 + 5 mM Met. They exhibited 1.65-fold lower cell viability than 2D with EP1 + 5 mM Met. ROS levels indicated a 2-fold increase in oxidative stress for EP1 + 5 mM Met, while the glucose uptake was limited to only 9 %. No significant change in the lactate production indicated glycolytic arrest and a non-conducive environment for MDA-MB-231 growth. Our results indicate that 3D cell culture, with a more realistic tumor environment that enhances cell death using metformin and electrical pulses could be a promising approach for TNBC therapeutic intervention studies.

Nerve growth factor inducible (VGF) is a secreted mediator for metastatic breast cancer tropism to the brain

Brain metastases are one of the most serious clinical problems in breast cancer (BC) progression, associated with lower survival rates and a lack of effective therapies. Thus, to dissect the early stages of the brain metastatic process, we studied the impact of brain organotropic BC cells' secretomes on the establishment of the brain pre-metastatic niche (PMN). We found that BC cells with specific tropism to the brain caused significant blood-brain barrier (BBB) disruption, as well as microglial activation, in both in vitro and in vivo models. Further, we searched for a brain-organotropic metastatic signature, as a promising source for the discovery of new biomarkers involved in brain metastatic progression. Of relevance, we identified VGF (nerve growth factor inducible) as a key mediator in this process, also impacting the BBB and microglial functions both in vitro and in vivo. In a series of human breast tumors, VGF was found to be expressed in both cancer cells and the adjacent stroma. Importantly, VGF-positive tumors showed a significantly worse prognosis and were associated with HER2 (human epidermal growth factor receptor 2) overexpression and triple-negative molecular signatures. Further clinical validation in primary tumors from metastatic BC cases showed a significant association between VGF and the brain metastatic location, clearly and significantly impacting on the prognosis of BC patients with brain metastasis. In conclusion, our study reveals a unique secretome signature for BC with a tropism for the brain, highlighting VGF as a crucial mediator in this process. Furthermore, its specific impact as a poor prognostic predictor for BC patients with brain metastasis opens new avenues to target VGF to control the progression of brain metastatic disease. © 2024 The Pathological Society of Great Britain and Ireland.

Challenges in validation of combination treatment strategies for CRC using patient-derived organoids

Patient-derived organoids (PDOs) established from tissues from various tumor types gave the foundation of ex vivo models to screen and/or validate the activity of many cancer drug candidates. Due to their phenotypic and genotypic similarity to the tumor of which they were derived, PDOs offer results that effectively complement those obtained from more complex models. Yet, their potential for predicting sensitivity to combination therapy remains underexplored. In this review, we discuss the use of PDOs in both validation and optimization of multi-drug combinations for personalized treatment strategies in CRC. Moreover, we present recent advancements in enriching PDOs with diverse cell types, enhancing their ability to mimic the complexity of in vivo environments. Finally, we debate how such sophisticated models are narrowing the gap in personalized medicine, particularly through immunotherapy strategies and discuss the challenges and future direction in this promising field.

Synthesis, Photo-Characterizations, and Pre-Clinical Studies on Advanced Cellular and Animal Models of Zinc(II) and Platinum(II) Sulfonyl-Substituted Phthalocyanines for Enhanced Vascular-Targeted Photodynamic Therapy

Two phthalocyanine derivatives tetra-peripherally substituted with tert-butylsulfonyl groups and coordinating either zinc(II) or platinum(II) ions have been synthesized and subsequently investigated in terms of their optical and photochemical properties, as well as biological activity in cellular, tissue-engineered, and animal models. Our research has revealed that both synthesized phthalocyanines are effective generators of reactive oxygen species (ROS). PtSO2tBu demonstrated an outstanding ability to generate singlet oxygen (ΦΔ = 0.87-0.99), while ZnSO2tBu in addition to 1O2 (ΦΔ = 0.45-0.48) generated efficiently other ROS, in particular ·OH. Considering future biomedical applications, the affinity of the tested phthalocyanines for biological membranes (partition coefficient; log Pow) and their primary interaction with serum albumin were also determined. To facilitate their biological administration, a water-dispersible formulation of these phthalocyanines was developed using Pluronic triblock copolymers to prevent self-aggregation and improve their delivery to cancer cells and tissues. The results showed a significant increase in cellular uptake and phototoxicity when phthalocyanines were incorporated into the customizable polymeric micelles. Moreover, the improved distribution in the body and photodynamic efficacy of the encapsulated phthalocyanines were investigated in hiPSC-delivered organoids and BALB/c mice bearing CT26 tumors. Both photosensitizers exhibit strong antitumor activity. Notably, vascular-targeted photodynamic therapy (V-PDT) led to complete tumor eradication in 84% of ZnSO2tBu and 100% of PtSO2tBu-treated mice, and no recurrence has so far been observed for up to five months after treatment. In the case of PtSO2tBu, the effect was significantly stronger, offering a wider range of light doses suitable for achieving effective PDT.

Use and Reuse of Animal Behavioral, Molecular, and Biochemical Data in Alzheimer's Disease Research: Focus on 3Rs and Saving People's Tax Dollars

Several decades of research on cell and animal models contributed tremendously to understanding human diseases. Particularly, research on rodents and non-human primates revealed that animal research is a major and important component in biomedical research in learning complex pathophysiological processes. Further, animal research helped us to understand human diseases, such as Alzheimer's disease. In addition, animal research has also helped us to test hundreds of drugs and develop treatments for human use. Researchers can gain a better understanding of key biological and physiological processes in humans by comparing them to laboratory animals. Based on their relevance and resemblance to people, or even usual living conditions, scientists rationalize the use of particular animal models in their studies. It is suggested that in the National Institutes of Health and other agencies-funded research, animal models should be carefully selected to study the biology and pathophysiology of human health and diseases such as Alzheimer's disease and other dementias. However, it is critical to use a minimum number of animals for human research. Further, it is also noted that the use and reuse of behavioral,  molecular, and biochemical data from wild-type (WT) control mice with mutant lines of disease models, as long as the genetic background is the same in both WT and disease mice. On the other hand, anonymous readers have challenged the use and reuse of WT mice data for comparison. In the current article, we discuss the minimum utility of animals, covering the 3Rs, Replacement, Reduction, and Refinement, and also discuss the use and reuse of behavioral, molecular, and biochemical data.

Unravelling the mechanics of gastric tissue: A comparison of constitutive models, damage probability and microstructural insights

With the increasing prevalence of obesity worldwide, bariatric surgery is becoming increasingly common. However, the mechanic of the gastric wall related to bariatric surgery complications remains to be investigated. This study aims to understand mechanical behaviour of stomach by developing advanced material laws for gastric tissue incorporating microstructure. A multi-scale characterisation of the porcine stomach wall was performed in the fundus and corpus anatomical regions and in circumferential and longitudinal orientations The protocol included uniaxial tensile testing until damage, survival analysis to provide damage probability, comparison of phenomenological (Fung and Ogden order 1, 2 and 3) and structural (Holzapfel fibre-reinforced) computational models fitted to the experimental data, and quantitative analysis of elastin and collagen fibre structure from histological slides. All constitutive models fitted the experimental data well (r2 > 0.988 and RSME<3.8 kPa). Longitudinal and circumferential elastic modulus in quasi linear phase were respectively 1.75 ± 1.2 MPa, 0.76 ± 0.35 MPa for fundus, and 2.30 ± 0.66 MPa, 1.36 ± 0.89 MPa for corpus, highlighting significant differences between orientations in fundus and corpus, with an overall softer fundus in the circumferential direction. Microstructure analysis illustrated collagen and elastin fibre orientation, dispersion and density. As microstructure appears to play an important role in stomach biomechanics, model incorporating fibre structure such as Holzapfel fibre-reinforced model, seem best suited to describe the material behaviour of the stomach wall. Future research should complement these findings with an expanded sample set in human models.

Vitamin D Deficiency Does Not Affect Cognition and Neurogenesis in Adult C57Bl/6 Mice

Vitamin D deficiency is a global problem. Vitamin D, the vitamin D receptor, and its enzymes are found throughout neuronal, ependymal, and glial cells in the brain and are implicated in certain processes and mechanisms in the brain. To investigate the processes affected by vitamin D deficiency in adults, we studied vitamin D deficient, control, and supplemented diets over 6 weeks in male and female C57Bl/6 mice. The effect of the vitamin D diets on proliferation in the neurogenic niches, changes in glial cells, as well as on memory, locomotion, and anxiety-like behavior, was investigated. Six weeks on a deficient diet was adequate time to reach deficiency. However, vitamin D deficiency and supplementation did not affect proliferation, neurogenesis, or astrocyte changes, and this was reflected on behavioral measures. Supplementation only affected microglia in the dentate gyrus of female mice. Indicating that vitamin D deficiency and supplementation do not affect these processes over a 6-week period.

Biomechanical Evaluation of an Atraumatic Polymer-assisted Peripheral Nerve Repair System Compared with Conventional Neurorrhaphy Techniques

Background

Microsuturing, the gold standard for peripheral nerve repair, can create tension and damage at the repair site, potentially impacting regeneration and causing neuroma formation. A sutureless and atraumatic polymer-assisted system was developed to address this challenge and support peripheral nerve repair. The system is based on a biocompatible and biodegradable biosynthetic polymer and consists of a coaptation chamber and a light-activated polymer for securing to the nerve. In this study, we compare the system's biomechanical performance and mechanism of action to microsutures and fibrin repairs.

Methods

The system's fixation force was compared with microsutures and fibrin glue, and evaluated across various nerve diameters through tensile testing. Tension and tissue morphology at the repair site were assessed using finite element modeling and scanning electron microscopy.

Results

The fixation force of the polymer-assisted repair was equivalent to microsutures and superior to fibrin glue. This force increased linearly with nerve diameter, highlighting the correlation between polymer surface contact area and performance. Finite element modeling analysis showed stress concentration at the repair site for microsuture repairs, whereas the polymer-assisted repair dissipated stress along the nerve, away from the repair site. Morphological analysis revealed nerve alignment with no tissue trauma for the polymer-assisted repair, unlike microsutures.

Conclusions

The mechanical performance of the polymer-assisted coaptation system is suitable for peripheral nerve repair. The achieved fixation forces are equivalent to those of microsutures and superior to fibrin glue, minimizing stress concentration at the repair site and avoiding trauma to the severed nerve ends.

Estimation of acceptable daily intake values based on modeling and in vivo mutagenicity of NDSRIs of fluoxetine, duloxetine and atomoxetine

Nitrosamine drug substance related impurities or NDSRIs can be formed if an active pharmaceutical ingredient (API) has an intrinsic secondary amine that can undergo nitrosation. This is a concern as 1) nitrosamines are potentially highly potent carcinogens, 2) secondary amines in API are common, and 3) NDSRIs that might form from such secondary amines will be of unknown carcinogenic potency. Approaches for evaluating NDSRIs include read across, quantum mechanical modeling of reactivity, in vitro mutation data, and transgenic in vivo mutation data. These approaches were used here to assess NDSRIs that could potentially form from the drugs fluoxetine, duloxetine and atomoxetine. Based on a read across informed by modeling of physicochemical properties and mechanistic activation from quantum mechanical modeling, NDSRIs of fluoxetine, duloxetine, and atomoxetine were 10-100-fold less potent compared with highly potent nitrosamines such as NDMA or NDEA. While the NDSRIs were all confirmed to be mutagenic in vitro (Ames assay) and in vivo (TGR) studies, the latter data indicated that the potency of the mutation response was ≥4400 ng/day for all compounds-an order of magnitude higher than published regulatory limits for these NDSRIs. The approaches described herein can be used qualitatively to better categorize NDSRIs with respect to potency and inform whether they are in the ICH M7 (R2) designated Cohort of Concern.

Advancing 3Rs: The Mouse Estrus Detector (MED) as a Low-Stress, Painless, and Efficient Tool for Estrus Determination in Mice

Determining the estrous cycle stages in mice is essential for optimizing breeding strategies, synchronizing experimental timelines, and facilitating studies in behavior, drug testing, and genetics. It is critical for reducing the production of genetically unmodified offspring in the generation and investigation of genetically modified animal models. An accurate detection of the estrus cycle is particularly relevant in the context of the 3Rs-Replacement, Reduction, and Refinement. The estrous cycle, encompassing the reproductive phases of mice, is key to refining experimental designs and addressing ethical issues related to the use of animals in research. This study presents results from two independent laboratories on the efficacy of the Mouse Estrus Detector (MED) from ELMI Ltd. (Latvia) for the accurate determination of the estrus phase. The female mice of five strains/stocks (CD1, FVB/N, C57Bl6/J, B6D2F1, and Swiss) were used. The results showed that the MEDProTM is a low-traumatic, simple, rapid, and painless method of estrus detection that supports the principles of the 3Rs. The use of the MEDProTM for estrus detection in mice caused minimal stress, enhanced mating efficiency, facilitated an increase in the number of embryos for in vitro fertilization, and allowed the production of the desired number of foster animals.

Studying the impact of geometrical and cellular cues on myogenesis with a skeletal muscle-on-chip

In the skeletal muscle tissue, cells are organized following an anisotropic architecture, which is both required during myogenesis when muscle precursor cells fuse to generate myotubes and for its contractile function. To build an in vitro skeletal muscle tissue, it is therefore essential to develop methods to organize cells in an anisotropic fashion, which can be particularly challenging, especially in 3D. In this study, we present a versatile muscle-on-chip system with adjustable collagen hollow tubes that can be seeded with muscle precursor cells. The collagen acts both as a tube-shaped hollow mold and as an extracellular matrix scaffold that can house other cell types for co-culture. We found that the diameter of the channel affects the organization of the muscle cells and that proper myogenesis was obtained at a diameter of 75 μm. In these conditions, muscle precursor cells fused into long myotubes aligned along these collagen channels, resulting in a fascicle-like structure. These myotubes exhibited actin striations and upregulation of multiple myogenic genes, reflecting their maturation. Moreover, we showed that our chip allowed muscle tissue culture and maturation over a month, with the possibility of fibroblast co-culture embedding in the collagen matrix.

Optimization of Experimental Infection of the Animal Model Galleria mellonella Linnaeus 1758 (Lepidoptera: Pyralidae) with the Gram-Positive Bacterium Micrococcus luteus

The aim of this work was to develop an experimental protocol for the infection of Galleria mellonella with Gram-positive bacteria. Some physiological characteristics of these insects are comparable to those of vertebrates, therefore allowing the replacement of mammals in the preclinical phases of drug development. G. mellonella Linnaeus 1758 (Lepidoptera: Pyralidae) is accepted as an alternative model for the study of infectious diseases. Since data on infection procedures with different bacterial strains are scarce and sometimes conflicting, also due to different and non-uniform protocols, we developed an experimental protocol that would allow for controlled and repeatable infections, using the Gram-positive bacterium GRAS (Generally Regarded As Safe) Micrococcus luteus. After analyzing the morphology and defining the growth rate of M. luteus, doses of between 101 and 106 CFU/larvae were administered to late-stage larvae. The survival rate of the larvae was monitored up to 7 days and the LD50 determined. The bacterial clearance capacity of the larvae after injection with 103 and 105 CFU/larvae was assessed by hemolymph bacterial load analysis. The results made it possible to define the growth curve of M. luteus correlated with the CFU count; based on the LD50 (103.8 CFU/larvae) calculated on the survival of G. mellonella, infections were carried out to evaluate the immune efficiency of the larvae in bacterial clearance. This protocol, standardized on G. mellonella larvae, could provide a functional tool to study the course of bacterial infections.

Phyto-pharmacological and computational profiling of Bombax ceiba Linn. Leaves revealed pharmacological properties against oxidation, hyperglycemia, pain, and diarrhea

The present study aimed to conduct phytochemical and pharmacological profiling of methanolic crude extract of leaves of Bombax ceiba Linn. via experimental and computational approaches. Six secondary metabolites were isolated chromatographically, and the structures were elucidated by extensive analyses of high-resolution 1H and 13C NMR data. The separated compounds were characterized as β-sitosterol (1), β-amyrin (2), β-amyrin acetate (3), β-amyrin palmitate (4), β-amyrone (5), and isoscopoletin (6). DPPH free radical scavenging assay, tail-tipping method, writhing assay, and castor oil-induced diarrheal mice methods, respectively, were used to assess the antioxidant, hypoglycemic, analgesic, and anti-diarrheal activities of the leaf extract of B. ceiba plant species. The study observed significant reductions (p < 0.05) in the level of blood glucose at 30, 60, 120, and 180 min following the administration of the crude extracts (200 mg/kg body weight (bw) and 400 mg/kg bw). These reductions occurred in a time-dependent manner. Additionally, both doses of the investigated extracts exhibited significant (p < 0.05) central and peripheral analgesic effects compared to morphine (2 mg/kg bw) and diclofenac sodium (50 mg/kg bw), respectively. Furthermore, the 400 mg/kg bw extract demonstrated anti-diarrheal activity, reducing 54.17 % of diarrheal episodes in mice compared to loperamide with 70.83 % inhibition. The computational investigations yielded results consistent with existing in vivo findings. The results obtained from molecular docking showed that the isolated compounds had a better or comparable binding affinity to the active binding sites of the glutathione reductase enzyme, mu-opioid receptor, cyclooxygenase 2 (COX-2), glucose transporter 3 (GLUT 3), and kappa opioid receptor. These findings may indicate that the compounds isolated from the B. ceiba plant species have antioxidant, analgesic, hypoglycemic, and anti-diarrheal, properties. Consequently, it was inferred that the plant B. ceiba might be beneficial in dealing with oxidation, diarrhea, hyperglycemia, and pain. Nonetheless, further investigations are necessary to perform thorough phytochemical profiling and elucidate the exact mechanistic ways of the crude extract and the isolated phytoconstituents.

Lyophilized Polyvinyl Alcohol and Chitosan Scaffolds Pre-Loaded with Silicon Dioxide Nanoparticles for Tissue Regeneration

Materials with a soft tissue regenerative capacity can be produced using biopolymer scaffolds and nanomaterials, which allow injured tissue to recover without any side effects or limitations. Four formulations were prepared using polyvinyl alcohol (PVA) and chitosan (CS), with silicon dioxide nanoparticles (NPs-SiO2) incorporated using the freeze-drying method at a temperature of -50 °C. TGA and DSC showed no change in thermal degradation, with glass transition temperatures around 74 °C and 77 °C. The interactions between the hydroxyl groups of PVA and CS remained stable. Scanning electron microscopy (SEM) indicated that the incorporation of NPs-SiO2 complemented the freeze-drying process, enabling the dispersion of the components on the polymeric matrix and obtaining structures with a small pore size (between 30 and 60 μm) and large pores (between 100 and 160 μm). The antimicrobial capacity analysis of Gram-positive and Gram-negative bacteria revealed that the scaffolds inhibited around 99% of K. pneumoniae, E. cloacae, and S. aureus ATCC 55804. The subdermal implantation analysis demonstrated tissue growth and proliferation, with good biocompatibility, promoting the healing process for tissue restoration through the simultaneous degradation and formation of type I collagen fibers. All the results presented expand the boundaries in tissue engineering and regenerative medicine by highlighting the crucial role of nanoparticles in optimizing scaffold properties.

A compared histopathological study on kidneys and eye bulbs in distinct clinical presentations of canine leishmaniasis by Leishmania infantum

Canine leishmaniasis (CanL) caused by Leishmania infantum commonly progresses with renal and ophthalmic lesions associated with active systemic disease. As chronic inflammation related to immune complex deposits is a pathophysiological factor in the development of both glomerulonephritis and uveitis, we aimed to evaluate renal and ocular histopathological lesions and analyze whether they were related to each other and the clinical degree of the disease. For that, we evaluated 15 dogs from CanL-endemic areas. L. infantum PCR-positive dogs were studied according to disease severity into two different groups: Group-1 (G1) had data from seven dogs with mild to moderate CanL and no history of treatment, and G2 was formed with eight dogs with severe to terminal disease that had not responded to CanL treatment. Histopathological analysis of kidneys showed higher frequencies and intensities of glomerular basement membrane thickening (p = 0.026), deposits in glomeruli (p = 0.016), epithelial necrosis (p = 0.020), tubular dilatation (p = 0.003) and interstitial fibrosis (p = 0.04) in G2 dogs than in G1 dogs. Surprisingly, the histopathology of eye bulbs showed a higher frequency and intensity of retinitis (p = 0.019) in G1 dogs than in G2 dogs. The comparative analysis showed that there was no correspondence between histopathological findings in kidneys versus eyes in milder or more severe CanL. Our findings suggested that (1) clinically undetectable eye alterations can be more precocious than those in kidneys in the development of CanL, and (2) the lower frequency of eye lesions and higher frequency of renal lesions in dogs with terminal disease even after treatment indicate that therapy may have been effective in reducing CanL-associated ophthalmic disease but not proportionally in reducing kidney disease.

Can next generation ecological risk assessment decisions be made today?-A case study of regulatory risk assessment in the United States

We examined the need for new in vivo avian toxicity testing for three common industrial chemicals (1,2 dichloropropane, 1,1,2-trichloroethane and triphenyl phosphate) based on estimated avian exposures using fugacity and multimedia fate models for current conditions of use compared to hazard information including existing in vivo test data for the chemicals and analogs, interspecies correlation estimates and results from hundreds of acute avian dietary toxicity studies. The data indicated that acute avian toxicity is not likely to be observed below 10 ppm in the diet for any chemical with the exception of those with a specific mode of toxic action. Modeling indicated low exposure potential for terrestrial birds to any of the three chemicals, with estimated dietary concentration of less than 0.001 ppm. Despite uncertainty associated with the underlying data sources, the four order of magnitude gap between potential exposure and a minimum hazard threshold suggests that additional avian in vivo testing would not generate valuable data. However, a weight of evidence approach for integrating data is necessary to engender greater confidence among government decision-makers in cases where data from a particular in vivo study is not expected to improve risk decision-making and an existing data gap can remain unfilled.

Correlation between Exposure to UFP and ACE/ACE2 Pathway: Looking for Possible Involvement in COVID-19 Pandemic

The overlap between the geographic distribution of COVID-19 outbreaks and pollution levels confirmed a correlation between exposure to atmospheric particulate matter (PM) and the SARS-CoV-2 pandemic. The RAS system is essential in the pathogenesis of inflammatory diseases caused by pollution: the ACE/AngII/AT1 axis activates a pro-inflammatory pathway, which is counteracted by the ACE2/Ang(1-7)/MAS axis, which activates an anti-inflammatory and protective pathway. However, ACE2 is also known to act as a receptor through which SARS-CoV-2 enters host cells to replicate. Furthermore, in vivo systems have demonstrated that exposure to PM increases ACE2 expression. In this study, the effects of acute and sub-acute exposure to ultrafine particles (UFP), originating from different anthropogenic sources (DEP and BB), on the levels of ACE2, ACE, COX-2, HO-1, and iNOS in the lungs and other organs implicated in the pathogenesis of COVID-19 were analyzed in the in vivo BALB/c male mice model. Exposure to UFP alters the levels of ACE2 and/or ACE in all examined organs, and exposure to sub-acute DEP also results in the release of s-ACE2. Furthermore, as evidenced in this and our previous works, COX-2, HO-1, and iNOS levels also demonstrated organ-specific alterations. These proteins play a pivotal role in the UFP-induced inflammatory and oxidative stress responses, and their dysregulation is linked to the development of severe symptoms in individuals infected with SARS-CoV-2, suggesting a heightened vulnerability or a more severe clinical course of the disease. UFP and SARS-CoV-2 share common pathways; therefore, in a "risk stratification" concept, daily exposure to air pollution may significantly increase the likelihood of developing a severe form of COVID-19, explaining, at least in part, the greater lethality of the virus observed in highly polluted areas.

Pharmacological Modulation of Intrarenal Pressure in a Porcine Model Using a Novel Isoprenaline-Eluting Guidewire

Introduction: Several complications of retrograde intrarenal surgery have been attributed to inadvertent increases in intrarenal pressure. We recently described the development of an innovative isoprenaline-eluting guidewire (IsoWire). The objective of this study was to investigate the impact of this IsoWire on the intrarenal pressure and evaluate its safety. Materials and Methods: This study was performed in 17 renal units using a porcine model. As controls, the intrarenal pressure, heart rate, and mean arterial pressure were measured for a duration of six minutes with a standard guidewire placed in the renal pelvis. For the experiment, the conventional guidewire was substituted with the IsoWire and the same parameters were measured. Blood samples were taken at one-minute intervals to measure plasma isoprenaline levels. This procedure was repeated on the opposite side. Results: The mean intrarenal pressure reduction was 29% (95% CI: 13%-53%). The mean isoprenaline effect time was 174 seconds. No changes in heart rate (p = .908) or mean arterial pressure (p = .749) were recorded after IsoWire insertion. Plasma isoprenaline levels were below the quantitation threshold. Isoprenaline concentrations in the plasma were below the quantification threshold. Ureteroscopy revealed no ureteral lesions. Conclusions: The IsoWire demonstrated a safe and effective reduction of intrarenal pressure. Additional research is necessary to determine whether ureteral smooth muscle relaxation generated by isoprenaline facilitates easier insertion of a ureteral access sheath, decreases the incidence of ureteral access sheath related ureteral lesions, or even encourage the practice of sheathless retrograde intrarenal surgery.

Model-based interspecies interpretation of botulinum neurotoxin type A on muscle-contraction inhibition

Botulinum neurotoxins (BoNTs) are commonly used in therapeutic and cosmetic applications. One such neurotoxin, BoNT type A (BoNT/A), has been studied widely for its effects on muscle function and contraction. Despite the importance of BoNT/A products, determining the blood concentrations of these toxins can be challenging. To address this, researchers have focused on pharmacodynamic (PD) markers, including compound muscle action potential (CMAP) and digit abduction scoring (DAS). In this study, we aimed to develop a probabilistic kinetic-pharmacodynamic (K-PD) model to interpret CMAP and DAS data obtained from mice and rats during the development of BoNT/A products. The researchers also wanted to gain a better understanding of how the estimated parameters from the model relate to the bridging of animal models to human responses. We used female Institute of Cancer Research mice and Sprague-Dawley (SD) rats to measure CMAP and DAS levels over 32 weeks after administering BoNT/A. We developed a muscle-contraction inhibition model using a virtual pharmacokinetic (PK) compartment combined with an indirect response model and performed model diagnostics using goodness-of-fit analysis, visual predictive checks (VPC), and bootstrap analysis. The CMAP and DAS profiles were dose-dependent, with recovery times varying depending on the administered dose. The final K-PD model effectively characterized the data and provided insights into species-specific differences in the PK and PD parameters. Overall, this study demonstrated the utility of PK-PD modeling in understanding the effects of BoNT/A and provides a foundation for future research on other BoNT/A products.

Electrospun scaffolds based on a PCL/starch blend reinforced with CaO nanoparticles for bone tissue engineering

Electrospun nanocomposite scaffolds with improved bioactive and biological properties were fabricated from a blend of polycaprolactone (PCL) and starch, and then combined with 5 wt% of calcium oxide (CaO) nanoparticles sourced from eggshells. SEM analyses showed scaffolds with fibrillar morphology and a three-dimensional structure. The hydrophilicity of scaffolds was improved with starch and CaO nanoparticles, which was evidenced by enhanced water absorption (3500 %) for 7 days. In addition, PCL/Starch/CaO scaffolds exhibited major degradation, with a mass loss of approximately 60 % compared to PCL/Starch and PCL/CaO. The PCL/Starch/CaO scaffolds decreased in crystallinity as intermolecular interactions between the nanoparticles retarded the mobility of the polymeric chains, leading to a significant increase in Young's modulus (ca. 60 %) and a decrease in tensile strength and elongation at break, compared to neat PCL. SEM-EDS, FT-IR, and XRD analyses indicated that PCL/Starch/CaO scaffolds presented a higher biomineralization capacity due to the ability to form hydroxyapatite (HA) in their surface after 28 days. The PCL/Starch/CaO scaffolds showed attractive biological performance, allowing cell adhesion and viability of M3T3-E1 preosteoblastic cells. In vivo analysis using a subdermal dorsal model in Wistar rats showed superior biocompatibility and improved resorption process compared to a pure PCL matrix. This biological analysis suggested that the PCL/Starch/CaO electrospun mats are suitable scaffolds for guiding the regeneration of bone tissue.

Exploring University Students' Perspectives on Animal Experimentation: Insights From a Cross-Sectional Study

Introduction Attitudes toward animal experimentation are rapidly evolving with time. This cross-sectional study intends to assess the attitudes of university students at Eastern Mediterranean University toward animal research based on different factors and lifestyle choices. Materials and methods Stratified random sampling was used. A total of 215 participants were chosen from the Faculties of Medicine, Pharmacy, Law, and the Department of Psychology (Faculty of Arts and Sciences). An open-access, self-administered, 14-question questionnaire was used. Mann-Whitney U tests were used for score comparisons. Results The response rate was 213 (99.07%). Eighty-eight (41.31%) of the participants were male. The mean age was 21.72 ± 2.23. Mann-Whitney U tests revealed significant differences for Q4, Q10, and Q14 (p = 0.012, 0.020, and 0.016, respectively) with respect to gender. Being a pet owner significantly affected the mean scores of Q7 and Q10 (p = 0.046 and p = 0.000, respectively). Conclusion The present study reveals nuanced student attitudes toward animal experimentation, balancing concern for animal welfare with the necessity of research. Gender and pet ownership significantly influence these views. The findings underscore the need for continued education on humane and ethical research practices. Future studies should broaden the demographic scope to better understand and track these attitudes over time.

Methods for Tattooing Xenopus laevis with a Rotary Tattoo Machine

Animal models expand the scope of biomedical research, furthering our understanding of developmental, molecular, and cellular biology and enabling researchers to model human disease. Recording and tracking individual animals allows researchers to reduce the number of animals required for study and refine practices to improve animal wellbeing. Several well-documented methods exist for marking and tracking mammals, including ear punching and ear tags. However, methods for marking aquatic amphibian species are limited, with the existing resources being outdated, ineffective, or prohibitively costly. In this manuscript, we outline methods and best practices for marking Xenopus laevis with a rotary tattoo machine. Proper tattooing results in high-quality tattoos, making individuals easily distinguishable for researchers and posing minimal risk to animals' health. We also highlight the causes of poor-quality tattoos, which can result in tattoos that fade quickly and cause unnecessary harm to animals. This approach allows researchers and veterinarians to mark amphibians, enabling them to track biological replicates and transgenic lines and to keep accurate records of animal health.

Staphylococcus pseudintermedius and Pseudomonas aeruginosa Lubbock Chronic Wound Biofilm (LCWB): a suitable dual-species model for in vitro studies

Antimicrobial treatment of methicillin-resistant Staphylococcus pseudintermedius associated with canine wounds represents an important challenge. The aim of this study was to create a canine wound infection model, Lubbock Chronic Wound Biofilm (LCWB), with a focus on S. pseudintermedius, drawing inspiration from the established human model involving Staphylococcus aureus. Methicillin-resistant S. pseudintermedius 115 (MRSP) and Pseudomonas aeruginosa 700 strains, isolated from dog wounds, were used to set up the LCWB at 24, 48 and 72 h. The LCWBs were evaluated in terms of volume, weight, and microbial CFU/mg. The microbial spatial distribution in the LCWBs was assessed by SEM and CLSM imaging. The best incubation time for the LCWB production in terms of volume (3.38 cm3 ± 0.13), weight (0.86 gr ± 0.02) and CFU/mg (up to 7.05 × 106 CFU/mg ± 2.89 × 105) was 48 h. The SEM and CLSM images showed a major viable microbial colonization at 48 h with non-mixed bacteria with a prevalence of MRSP on the surface and P. aeruginosa 700 in the depth of the wound. The obtained findings demonstrate the capability of S. pseudintermedius to grow together P. aeruginosa in the LCWB model, representing the suitable model to reproduce the animal chronic wound in vitro.

Mapping the scientific output of organoids for animal and human modeling infectious diseases: a bibliometric assessment

The escalation of antibiotic resistance, pandemics, and nosocomial infections underscores the importance of research in both animal and human infectious diseases. Recent advancements in three-dimensional tissue cultures, or "organoids", have revolutionized the development of in vitro models for infectious diseases. Our study conducts a bibliometric analysis on the use of organoids in modeling infectious diseases, offering an in-depth overview of this field's current landscape. We examined scientific contributions from 2009 onward that focused on organoids in host‒pathogen interactions using the Web of Science Core Collection and OpenAlex database. Our analysis included temporal trends, reference aging, author, and institutional productivity, collaborative networks, citation metrics, keyword cluster dynamics, and disruptiveness of organoid models. VOSviewer, CiteSpace, and Python facilitated this analytical assessment. The findings reveal significant growth and advancements in organoid-based infectious disease research. Analysis of keywords and impactful publications identified three distinct developmental phases in this area that were significantly influenced by outbreaks of Zika and SARS-CoV-2 viruses. The research also highlights the synergistic efforts between academia and publishers in tackling global pandemic challenges. Through mostly consolidating research efforts, organoids are proving to be a promising tool in infectious disease research for both human and animal infectious disease. Their integration into the field necessitates methodological refinements for better physiological emulation and the establishment of extensive organoid biobanks. These improvements are crucial for fully harnessing the potential of organoids in understanding infectious diseases and advancing the development of targeted treatments and vaccines.

(3D) Bioprinting-Next Dimension of the Pharmaceutical Sector

To create a review of the published scientific literature on the benefits and potential perspectives of the use of 3D bio-nitrification in the field of pharmaceutics. This work was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines for reporting meta-analyses and systematic reviews. The scientific databases PubMed, Scopus, Google Scholar, and ScienceDirect were used to search and extract data using the following keywords: 3D bioprinting, drug research and development, personalized medicine, pharmaceutical companies, clinical trials, drug testing. The data points to several aspects of the application of bioprinting in pharmaceutics were reviewed. The main applications of bioprinting are in the development of new drug molecules as well as in the preparation of personalized drugs, but the greatest benefits are in terms of drug screening and testing. Growth in the field of 3D printing has facilitated pharmaceutical applications, enabling the development of personalized drug screening and drug delivery systems for individual patients. Bioprinting presents the opportunity to print drugs on demand according to the individual needs of the patient, making the shape, structure, and dosage suitable for each of the patient's physical conditions, i.e., print specific drugs for controlled release rates; print porous tablets to reduce swallowing difficulties; make transdermal microneedle patches to reduce patient pain; and so on. On the other hand, bioprinting can precisely control the distribution of cells and biomaterials to build organoids, or an Organ-on-a-Chip, for the testing of drugs on printed organs mimicking specified disease characteristics instead of animal testing and clinical trials. The development of bioprinting has the potential to offer customized drug screening platforms and drug delivery systems meeting a range of individualized needs, as well as prospects at different stages of drug development and patient therapy. The role of bioprinting in preclinical and clinical testing of drugs is also of significant importance in terms of shortening the time to launch a medicinal product on the market.

Embracing prospects for reducing the numbers of animals used in aquaculture research

The principles of three Rs-REPLACEMENT, REDUCTION, and REFINEMENT-govern the protection and use of animals, including fish, for research purposes in the European Union and Norway. In this paper, we discuss some straightforward steps to simplify the delivery of these principles at the idea stage and adapt some of these examples for conducting fish trials related to health and welfare. Although some of the approaches are well established in other animal science arenas, we believe there can be a timely recap of their key facets. We discuss a number of simple strategies to emphasize how a reduction in fish numbers can be achieved from initial project conception to implementation, highlighting not only their advantages but also their limitations. We also highlight the role that funding agencies can play in the implementation of the 3R principles in aquaculture research. These simple points can be used in frameworks to initiate a broader and dynamic intersectoral dialogue among stakeholders of aquaculture research on how to promote ethics and embrace opportunities for this within the tenets of the 3Rs.

Adverse hematological profiles associated with chlorpromazine antipsychotic treatment in male rats: Preventive and reversal mechanisms of taurine and coenzyme-Q10

Chlorpromazine (CPZ) is one of the most effective antipsychotic drugs used for managing psychotic related disorders owing to its dopamine receptor blocking action. However, pharmacological investigations against CPZ's cytotoxic effect have remained scarce. Hence, this study investigated the preventive and reversal effects of taurine and coenzyme-Q10 (COQ-10), which are compounds with proven natural antioxidant properties, against CPZ-induced hematological impairments in male rats. In the preventive study, rats received oral saline (10 ml/kg), taurine (150 mg/kg/day), COQ-10 (10 mg/kg/day) or in combination for 56 days, alongside CPZ (30 mg/kg, p.o.) between days 29-56. In the reversal protocol, rats had CPZ repeatedly for 56 days before taurine and COQ-10 treatments or their combination from days 29-56. Rats were also given taurine (150 mg/kg/day), and COQ-10 (10 mg/kg/day) alone for 56 days. Serums were extracted and assayed for hematological, with oxidative and inflammatory markers. CPZ induced decreased red/white blood cells, erythropoietin, platelet count, packed cell volume and hemoglobin, neutrophil, and lymphocyte, which were prevented and reversed by taurine and COQ-10, or their combination. Taurine and COQ-10 improved mean corpuscular volume, hemoglobin concentration, with increased erythropoietin levels relative to CPZ groups. CPZ-induced increased malondialdehyde, tumor necrosis factor-alpha and interleukin-6 levels with decreased interleukin-10, glutathione, and superoxide-dismutase were prevented and reversed by taurine and COQ-10 in comparison with CPZ groups. Taurine and COQ-10 alone notably improved the antioxidant/anti-inflammatory status relative to controls. Among other mechanisms, taurine and COQ-10 abated CPZ-induced hematological deficiencies, via decreased serum levels of oxidative stress, and pro-inflammatory cytokines release, with increased antioxidants and anti-inflammation function.

An improved method for toxicological profiling of chemical substances

Toxicity profiling is an integral part of the drug discovery pipeline. The 3Rs principle-Replacement, Reduction, and Refinement, is considered a golden rule in determining the most appropriate approach for toxicity studies. The acute toxicity study with proper estimate of median lethal dose (LD50) is usually an initial procedure for the determination of most suitable test doses for preclinical toxicological and pharmacological profiling. Several methods, which have been devised to determine the LD50, are faced with the challenge of using a large number of animals and time constraints. Despite the inherent advantage of the newer OECD Test Guidelines, the increasing concerns among toxicologists, the regulatory authorities and the general public, on the need to adhere to 3Rs principle, necessitated the need for an improved approach. Such an approach should not only minimize the time and number of animals required, but also take into cognizance animal welfare, and give accurate, comparable, and reproducible results across laboratories. While taking advantage of the inherent merits of the existing methods, here is presented the mathematical basis and evaluation of an improved method for toxicity profiling of test substances and estimation of LD50. The method makes use of the generated Table of values for the selection of appropriate test doses. Our proposed method has capacities to optimize the time and number of animal use, ensure more reliable and reproducible results across laboratories, allow for easy selection of doses for subsequent toxicity profiling, and be adaptable to other biological screening beyond toxicity studies.

A microscope in your pocket: can smartphones be used to perform microsurgery?

PURPOSE

To evaluate the use of the latest generation smartphone camera in performing arterial microanastomosis in rats.

METHODS

Ten Wistar rats were divided into 2 groups and underwent anastomosis of the right carotid artery with the aid of magnification from a microscope (group M) and a smartphone camera (group S), to compare patency in 72 hours, as well as to measure the weight of the animals, diameter of the carotid arteries and anastomosis time.

RESULTS

There was no statistical difference between the weight of the animals or the diameter of the carotid arteries. There was a statistical difference for the time spent on anastomoses, which was greater in group S, with higher rates of thrombosis (p < 0.05).

CONCLUSIONS

Although our patency and anastomosis time results were statistically lower in the smartphone group, there was success in some cases. As the segment continues to progress, it is likely that the results will improve in line with the evolution of camera technology.

Multiplexed In Vivo Screening Using Barcoded Aptamer Technology to Identify Oligonucleotide-Based Targeting Reagents

Recent FDA approvals of mRNA vaccines, short-interfering RNAs, and antisense oligonucleotides highlight the success of oligonucleotides as therapeutics. Aptamers are excellent affinity reagents that can selectively label protein biomarkers, but their clinical application has lagged. When formulating a given aptamer for in vivo use, molecular design details can determine biostability and biodistribution; therefore, extensive postselection manipulation is often required for each new design to identify clinically useful reagents harboring improved pharmacokinetic properties. Few methods are available to comprehensively screen such aptamers, especially in vivo, constituting a significant bottleneck in the field. In this study, we introduce barcoded aptamer technology (BApT) for multiplexed screening of predefined aptamer formulations in vitro and in vivo. We demonstrate this technology by simultaneously investigating 20 aptamer formulations, each harboring different molecular designs, for targeting Non-Small Cell Lung Cancer cells and tumors. Screening in vitro identified a 45 kDa bispecific formulation as the best cancer cell targeting reagent, whereas screening in vivo identified a 30 kDa monomeric formulation as the best tumor-specific targeting reagent. The multiplexed analysis pipeline also identified biodistribution phenotypes shared among formulations with similar molecular architectures. The BApT approach we describe here has the potential for broad application to fields where oligonucleotide-based targeting reagents are desired.

Modelling human genetic disorders in Xenopus tropicalis

Recent progress in human disease genetics is leading to rapid advances in understanding pathobiological mechanisms. However, the sheer number of risk-conveying genetic variants being identified demands in vivo model systems that are amenable to functional analyses at scale. Here we provide a practical guide for using the diploid frog species Xenopus tropicalis to study many genes and variants to uncover conserved mechanisms of pathobiology relevant to human disease. We discuss key considerations in modelling human genetic disorders: genetic architecture, conservation, phenotyping strategy and rigour, as well as more complex topics, such as penetrance, expressivity, sex differences and current challenges in the field. As the patient-driven gene discovery field expands significantly, the cost-effective, rapid and higher throughput nature of Xenopus make it an essential member of the model organism armamentarium for understanding gene function in development and in relation to disease.

In-process quality control in foot-and-mouth disease vaccine production by detection of viral non-structural proteins using chemiluminescence dot blot assay

Foot-and-mouth disease (FMD) is a contagious viral disease of cloven-footed animals. Immunization with inactivated virus vaccine is effective to control the disease. Six-monthly vaccination regimen in endemic regions has proven to be effective. To enable the differentiation of infected animals from those vaccinated, non-structural proteins (NSPs) are excluded during vaccine production. While the antibodies to structural proteins (SPs) could be observed both in vaccinated and infected animals, NSP antibodies are detectable only in natural infection. Quality control assays that detect NSPs in vaccine antigen preparations, are thus vital in the FMD vaccine manufacturing process. In this study, we designed a chemiluminescence dot blot assay to detect the 3A and 3B NSPs of FMDV. It is sensitive enough to detect up to 20 ng of the NSP, and exhibited specificity as it does not react with the viral SPs. This cost-effective assay holds promise in quality control assessment in FMD vaccine manufacturing.

Spatiotemporally resolved colorectal oncogenesis in mini-colons ex vivo

Three-dimensional organoid culture technologies have revolutionized cancer research by allowing for more realistic and scalable reproductions of both tumour and microenvironmental structures1-3. This has enabled better modelling of low-complexity cancer cell behaviours that occur over relatively short periods of time4. However, available organoid systems do not capture the intricate evolutionary process of cancer development in terms of tissue architecture, cell diversity, homeostasis and lifespan. As a consequence, oncogenesis and tumour formation studies are not possible in vitro and instead require the extensive use of animal models, which provide limited spatiotemporal resolution of cellular dynamics and come at a considerable cost in terms of resources and animal lives. Here we developed topobiologically complex mini-colons that are able to undergo tumorigenesis ex vivo by integrating microfabrication, optogenetic and tissue engineering approaches. With this system, tumorigenic transformation can be spatiotemporally controlled by directing oncogenic activation through blue-light exposure, and emergent colon tumours can be tracked in real-time at the single-cell resolution for several weeks without breaking the culture. These induced mini-colons display rich intratumoural and intertumoural diversity and recapitulate key pathophysiological hallmarks displayed by colorectal tumours in vivo. By fine-tuning cell-intrinsic and cell-extrinsic parameters, mini-colons can be used to identify tumorigenic determinants and pharmacological opportunities. As a whole, our study paves the way for cancer initiation research outside living organisms.

Behavioral and pharmacological characterization of planarian nociception

Introduction

Pain mostly arises because specialized cells called nociceptors detect harmful or potentially harmful stimuli. In lower animals with less convoluted nervous system, these responses are believed to be purely nociceptive. Amongst invertebrate animal models, planarians are becoming popular in a wide range of pharmacological and behavioral studies beyond the field of regeneration. Recent publications led the way on pain studies by focusing on nociceptive behaviors such as the 'scrunching' gait displayed under various noxious stimuli, as opposed to the 'gliding' gait planarians usually adopt in normal conditions.

Methods

In this study, we adapted commonly used nociceptive tests to further explore nociception in planarians of the species Girardia dorotocephala. By using behavioral analysis in open fields and place preferences, we managed to set up chemical, thermal and mechanical nociceptive tests. We also adapted RNA interference protocols and explored the effects of knocking down TRPA1 ion channels, one of the main effectors of chemically and thermally-induced nociceptive responses in vertebrates.

Results

Consequently, we demonstrated the reliability of the scrunching gait in this planarian species, which they displayed in a dose-dependent manner when exposed to the irritant AITC. We also showed that suppressing the expression of TRPA1 ion channels completely suppressed the scrunching gait, demonstrating the involvement of TRPA1 nociceptors in this nociceptive reaction. Besides, we also explored the effects of two common analgesics that both displayed strong antinociceptive properties. First, morphine reduced the chemically-induced nociceptive scrunching gaits by more than 20% and shifted the E C 50 of the dose-response curve by approximately 10 μM. Secondly, the NSAID meloxicam drastically reduced chemically-induced scrunching by up to 60% and reduced heat avoidance in place preference tests.

Discussion

Thus, we managed to characterize both behavioral and pharmacological aspects of G. dorotocephala's nociception, further developing the use of planarians as a replacement model in pain studies and more globally the study of invertebrate nociception.

High-Spatial-Resolution Benchtop X-ray Fluorescence Imaging through Bragg-Diffraction-Based Focusing with Bent Mosaic Graphite Crystals: A Simulation Study

X-ray fluorescence imaging (XFI) can localize diagnostic or theranostic entities utilizing nanoparticle (NP)-based probes at high resolution in vivo, in vitro, and ex vivo. However, small-animal benchtop XFI systems demonstrating high spatial resolution (variable from sub-millimeter to millimeter range) in vivo are still limited to lighter elements (i.e., atomic number Z≤45). This study investigates the feasibility of focusing hard X-rays from solid-target tubes using ellipsoidal lens systems composed of mosaic graphite crystals with the aim of enabling high-resolution in vivo XFI applications with mid-Z (42≤Z≤64) elements. Monte Carlo simulations are performed to characterize the proposed focusing-optics concept and provide quantitative predictions of the XFI sensitivity, in silico tumor-bearing mice models loaded with palladium (Pd) and barium (Ba) NPs. Based on simulation results, the minimum detectable total mass of PdNPs per scan position is expected to be on the order of a few hundred nanograms under in vivo conform conditions. PdNP masses as low as 150 ng to 50 ng could be detectable with a resolution of 600 μm when imaging abdominal tumor lesions across a range of low-dose (0.8 μGy) to high-dose (8 μGy) exposure scenarios. The proposed focusing-optics concept presents a potential step toward realizing XFI with conventional X-ray tubes for high-resolution applications involving interesting NP formulations.

Biological activity of lyophilized chitosan scaffolds with inclusion of chitosan and zinc oxide nanoparticles

The constant demand for biocompatible and non-invasive materials for regenerative medicine in accidents and various diseases has driven the development of innovative biomaterials that promote biomedical applications. In this context, using sol-gel and ionotropic gelation methods, zinc oxide nanoparticles (NPs-ZnO) and chitosan nanoparticles (NPs-CS) were synthesized with sizes of 20.0 nm and 11.98 nm, respectively. These nanoparticles were incorporated into chitosan scaffolds through the freeze-drying method, generating a porous morphology with small (<100 μm), medium (100-200 μm), and large (200-450 μm) pore sizes. Moreover, the four formulations showed preliminary bioactivity after hydrolytic degradation, facilitating the formation of a hydroxyapatite (HA) layer on the scaffold surface, as evidenced by the presence of Ca (4%) and P (5.1%) during hydrolytic degradation. The scaffolds exhibited average antibacterial activity of F1 = 92.93%, F2 = 99.90%, F3 = 74.10%, and F4 = 88.72% against four bacterial strains: K. pneumoniae, E. cloacae, S. enterica, and S. aureus. In vivo, evaluation confirmed the biocompatibility of the functionalized scaffolds, where F2 showed accelerated resorption attributed to the NPs-ZnO. At the same time, F3 exhibited controlled degradation with NPs-CS acting as initiation points for degradation. On the other hand, F4 combined NPs-CS and NPs-ZnO, resulting in progressive degradation, reduced inflammation, and an organized extracellular matrix. All the results presented expand the boundaries in tissue engineering and regenerative medicine by highlighting the crucial role of nanoparticles in optimizing scaffold properties.

Melanocytes in regenerative medicine applications and disease modeling

Melanocytes are dendritic cells localized in skin, eyes, hair follicles, ears, heart and central nervous system. They are characterized by the presence of melanosomes enriched in melanin which are responsible for skin, eye and hair pigmentation. They also have different functions in photoprotection, immunity and sound perception. Melanocyte dysfunction can cause pigmentary disorders, hearing and vision impairments or increased cancer susceptibility. This review focuses on the role of melanocytes in homeostasis and disease, before discussing their potential in regenerative medicine applications, such as for disease modeling, drug testing or therapy development using stem cell technologies, tissue engineering and extracellular vesicles.

The Evolution of Technology-Driven In Vitro Models for Neurodegenerative Diseases

The alteration in the neural circuits of both central and peripheral nervous systems is closely related to the onset of neurodegenerative disorders (NDDs). Despite significant research efforts, the knowledge regarding NDD pathological processes, and the development of efficacious drugs are still limited due to the inability to access and reproduce the components of the nervous system and its intricate microenvironment. 2D culture systems are too simplistic to accurately represent the more complex and dynamic situation of cells in vivo and have therefore been surpassed by 3D systems. However, both models suffer from various limitations that can be overcome by employing two innovative technologies: organ-on-chip and 3D printing. In this review, an overview of the advantages and shortcomings of both microfluidic platforms and extracellular matrix-like biomaterials will be given. Then, the combination of microfluidics and hydrogels as a new synergistic approach to study neural disorders by analyzing the latest advances in 3D brain-on-chip for neurodegenerative research will be explored.

3R-Refinement principles: elevating rodent well-being and research quality

This review article delves into the details of the 3R-Refinement principles as a vital framework for ethically sound rodent research laboratory. It highlights the core objective of the refinement protocol, namely, to enhance the well-being of laboratory animals while simultaneously improving the scientific validity of research outcomes. Through an exploration of key components of the refinement principles, the article outlines how these ethics should be implemented at various stages of animal experiments. It emphasizes the significance of enriched housing environments that reduce stress and encourage natural behaviors, non-restraint methods in handling and training, refined dosing and sampling techniques that prioritize animal comfort, the critical role of optimal pain management and the importance of regular animal welfare assessment in maintaining the rodents well-being. Additionally, the advantages of collaboration with animal care and ethics committees are also mentioned. The other half of the article explains the extensive benefits of the 3R-Refinement protocol such as heightened animal welfare, enhanced research quality, reduced variability, and positive feedback from researchers and animal care staff. Furthermore, it addresses avenues for promoting the adoption of the protocol, such as disseminating best practices, conducting training programs, and engaging with regulatory bodies. Overall, this article highlights the significance of 3R-Refinement protocol in aligning scientific advancement with ethical considerations along with shaping a more compassionate and responsible future for animal research.

Delay of punishment highlights differential vulnerability to developing addiction-like behavior toward sweet food

Resistance to punishment is commonly used to measure the difficulty in refraining from rewarding activities when negative consequences ensue, which is a hallmark of addictive behavior. We recently developed a progressive shock strength (PSS) procedure in which individual rats can titrate the amount of punishment that they are willing to tolerate to obtain food rewards. Here, we investigated the effects of a range of delays (0-12 s) on resistance to punishment measured by PSS break points. As expected from delay discounting principles, we found that delayed shock was less effective as a punisher, as revealed by higher PSS breakpoints. However, this discounting effect was not equally distributed in the population of rats, and the introduction of a delay highlighted the existence of two populations: rats that were sensitive to immediate punishment were also sensitive to delayed shock, whereas rats that were resistant to immediate punishment showed strong temporal discounting of delayed punishment. Importantly, shock-sensitive rats suppressed responding even in subsequent non-punishment sessions, and they differed from shock-resistant rats in anxiety-like behavior, but not in sensitivity to pain. These results show that manipulation of temporal contingencies of punishment in the PSS procedure provides a valuable tool to identify individuals with a double vulnerability to addiction: low sensitivity to aversion and excessive discounting of negative future consequences. Conversely, the shock-sensitive population may provide a model of humans who are vulnerable to opportunity loss due to excessive anxiety.

Improving in vivo assays in snake venom and antivenom research: A community discussion

On the 26 th January 2023, a free to attend, 'improving in vivo snake venom research: a community discussion' meeting was held virtually. This webinar brought together researchers from around the world to discuss current neutralisation of venom lethality mouse assays that are used globally to assess the efficacy of therapies for snakebite envenoming. The assay's strengths and weaknesses were highlighted, and we discussed what improvements could be made to refine and reduce animal testing, whilst supporting preclinical antivenom and drug discovery for snakebite envenoming. This report summarises the issues highlighted, the discussions held, with additional commentary on key perspectives provided by the authors.

A validation study to analyze the reliability of center of pressure data in static posturography in dogs

Introduction

Center of pressure (COP) parameters are frequently assessed to analyze movement disorders in humans and animals. Methodological discrepancies are a major concern when evaluating conflicting study results. This study aimed to assess the inter-observer reliability and test-retest reliability of body COP parameters including mediolateral and craniocaudal sway, total length, average speed and support surface in healthy dogs during quiet standing on a pressure plate. Additionally, it sought to determine the minimum number of trials and the shortest duration necessary for accurate COP assessment.

Materials and methods

Twelve clinically healthy dogs underwent three repeated trials, which were analyzed by three independent observers to evaluate inter-observer reliability. Test-retest reliability was assessed across the three trials per dog, each lasting 20 seconds (s). Selected 20 s measurements were analyzed in six different ways: 1 × 20 s, 1 × 15 s, 2 × 10 s, 4 × 5 s, 10 × 2 s, and 20 × 1 s.

Results

Results demonstrated excellent inter-observer reliability (ICC ≥ 0.93) for all COP parameters. However, only 5 s, 10 s, and 15 s measurements achieved the reliability threshold (ICC ≥ 0.60) for all evaluated parameters.

Discussion

The shortest repeatable durations were obtained from either two 5 s measurements or a single 10 s measurement. Most importantly, statistically significant differences were observed between the different measurement durations, which underlines the need to standardize measurement times in COP analysis. The results of this study aid scientists in implementing standardized methods, thereby easing comparisons across studies and enhancing the reliability and validity of research findings in veterinary medicine.

Kinetics of Inflammatory Mediators in the Immune Response to Burn Injury: Systematic Review and Meta-Analysis of Animal Studies

Burns are often accompanied by a dysfunctional immune response, which can lead to systemic inflammation, shock, and excessive scarring. The objective of this study was to provide insight into inflammatory pathways associated with burn-related complications. Because detailed information on the various inflammatory mediators is scattered over individual studies, we systematically reviewed animal experimental data for all reported inflammatory mediators. Meta-analyses of 352 studies revealed a strong increase in cytokines, chemokines, and growth factors, particularly 19 mediators in blood and 12 in burn tissue. Temporal kinetics showed long-lasting surges of proinflammatory cytokines in blood and burn tissue. Significant time-dependent effects were seen for IL-1β, IL-6, TGF-β1, and CCL2. The response of anti-inflammatory mediators was limited. Burn technique had a profound impact on systemic response levels. Large burn size and scalds further increased systemic, but not local inflammation. Animal characteristics greatly affected inflammation, for example, IL-1β, IL-6, and TNF-α levels were highest in young, male rats. Time-dependent effects and dissimilarities in response demonstrate the importance of appropriate study design. Collectively, this review presents a general overview of the burn-induced immune response exposing inflammatory pathways that could be targeted through immunotherapy for burn patients and provides guidance for experimental set-ups to advance burn research.

Dual-Responsive Nanorobot-Based Marsupial Robotic System for Intracranial Cross-Scale Targeting Drug Delivery

Nanorobots capable of active movement are an exciting technology for targeted therapeutic intervention. However, the extensive motion range and hindrance of the blood-brain barrier impeded their clinical translation in glioblastoma therapy. Here, a marsupial robotic system constructed by integrating chemical/magnetic hybrid nanorobots (child robots) with a miniature magnetic continuum robot (mother robot) for intracranial cross-scale targeting drug delivery is reported. For primary targeting on macroscale, the continuum robot enters the cranial cavity through a minimally invasive channel (e.g., Ommaya device) in the skull and transports the nanorobots to pathogenic regions. Upon circumventing the blood-brain barrier, the released nanorobots perform secondary targeting on microscale to further enhance the spatial resolution of drug delivery. In vitro experiments against primary glioblastoma cells derived from different patients are conducted for personalized treatment guidance. The operation feasibility within organisms is shown in ex vivo swine brain experiments. The biosafety of the treatment system is suggested in in vivo experiments. Owing to the hierarchical targeting method, the targeting rate, targeting accuracy, and treatment efficacy have improved greatly. The marsupial robotic system offers a novel intracranial local therapeutic strategy and constitutes a key milestone in the development of glioblastoma treatment platforms.

Revolutionizing biomedical research: The imperative need for heart-kidney-connected organoids

Organoids significantly advanced our comprehension of organ development, function, and disease modeling. This Perspective underscores the potential of heart-kidney-connected organoids in understanding the intricate relationship between these vital organs, notably the cardiorenal syndrome, where dysfunction in one organ can negatively impact the other. Conventional models fall short in replicating this complexity, necessitating an integrated approach. By co-culturing heart and kidney organoids, combined with microfluidic and 3D bioprinting technologies, a more accurate representation of in vivo conditions can be achieved. Such interconnected systems could revolutionize our grasp of multi-organ diseases, drive drug discovery by evaluating therapeutic agents on both organs simultaneously, and reduce the need for animal models. In essence, heart-kidney-connected organoids present a promising avenue to delve deeper into the pathophysiology underlying cardiorenal disorders, bridging existing knowledge gaps, and advancing biomedical research.

Options for substantiating protein content claims for conventional foods

In Canada and the United States, front-of-package protein content claims require data to support the quality of the protein. In general, protein quality reflects the product of the amino acid composition of the food protein relative to human amino acid requirements and a measure of digestibility. The currently accepted method in both jurisdictions is the protein digestibility-corrected amino acid score (PDCAAS) that requires the measurement of true fecal protein (nitrogen) digestibility. The latter must be measured in vivo using a rat model. This requirement for animal testing is inconsistent with international efforts to reduce the usage of animals in testing for regulatory purposes. The current commentary positions four options to remove the need to use animal testing for determining protein quality, when considering protein content claim substantiation. These options include (i) a focus on protein quantity alone; (ii) the use of the amino acid score alone, with no correction for digestibility; (iii) the use of a fixed digestibility coefficient to estimate protein quality; and (iv) the use of in vitro methods to measure protein and/or amino acid digestibility. The relative merits and deficiencies of the options are positioned with the goal of encouraging dialogue within the regulatory agencies to move towards alternative approaches for substantiating protein content claims on foods, including those derived from plant-based sources.

Utilizing murine dendritic cell line DC2.4 to evaluate the immunogenicity of subunit vaccines in vitro

Subunit vaccines hold substantial promise in controlling infectious diseases, due to their superior safety profile, specific immunogenicity, simplified manufacturing processes, and well-defined chemical compositions. One of the most important end-targets of vaccines is a subset of lymphocytes originating from the thymus, known as T cells, which possess the ability to mount an antigen-specific immune response. Furthermore, vaccines confer long-term immunity through the generation of memory T cell pools. Dendritic cells are essential for the activation of T cells and the induction of adaptive immunity, making them key for the in vitro evaluation of vaccine efficacy. Upon internalization by dendritic cells, vaccine-bearing antigens are processed, and suitable fragments are presented to T cells by major histocompatibility complex (MHC) molecules. In addition, DCs can secrete various cytokines to crosstalk with T cells to coordinate subsequent immune responses. Here, we generated an in vitro model using the immortalized murine dendritic cell line, DC2.4, to recapitulate the process of antigen uptake and DC maturation, measured as the elevation of CD40, MHC-II, CD80 and CD86 on the cell surface. The levels of key DC cytokines, tumor necrosis alpha (TNF-α) and interleukin-10 (IL-10) were measured to better define DC activation. This information served as a cost-effective and rapid proxy for assessing the antigen presentation efficacy of various vaccine formulations, demonstrating a strong correlation with previously published in vivo study outcomes. Hence, our assay enables the selection of the lead vaccine candidates based on DC activation capacity prior to in vivo animal studies.