Improving Translation by Identifying Evidence for More Human-Relevant Preclinical Strategies

Novel Insights into the Aortic Mechanical Properties of Mice Modeling Hereditary Aortic Diseases

OBJECTIVE

 Hereditary aortic diseases (hADs) increase the risk of aortic dissections and ruptures. Recently, we have established an objective approach to measure the rupture force of the murine aorta, thereby explaining the outcomes of clinical studies and assessing the added value of approved drugs in vascular Ehlers-Danlos syndrome (vEDS). Here, we applied our approach to six additional mouse hAD models.

MATERIAL AND METHODS

 We used two mouse models (Fbn1C1041G and Fbn1mgR ) of Marfan syndrome (MFS) as well as one smooth-muscle-cell-specific knockout (SMKO) of Efemp2 and three CRISPR/Cas9-engineered knock-in models (Ltbp1, Mfap4, and Timp1). One of the two MFS models was subjected to 4-week-long losartan treatment. Per mouse, three rings of the thoracic aorta were prepared, mounted on a tissue puller, and uniaxially stretched until rupture.

RESULTS

 The aortic rupture force of the SMKO and both MFS models was significantly lower compared with wild-type mice but in both MFS models higher than in mice modeling vEDS. In contrast, the Ltbp1, Mfap4, and Timp1 knock-in models presented no impaired aortic integrity. As expected, losartan treatment reduced aneurysm formation but surprisingly had no impact on the aortic rupture force of our MFS mice.

CONCLUSION

 Our read-out system can characterize the aortic biomechanical integrity of mice modeling not only vEDS but also related hADs, allowing the aortic-rupture-force-focused comparison of mouse models. Furthermore, aneurysm progression alone may not be a sufficient read-out for aortic rupture, as antihypertensive drugs reducing aortic dilatation might not strengthen the weakened aortic wall. Our results may enable identification of improved medical therapies of hADs.

The Rise of Pluripotent Stem Cell-Derived Glia Models of Neuroinflammation

Neuroinflammation is a blanket term that describes the body's complex inflammatory response in the central nervous system (CNS). It encompasses a phenotype shift to a proinflammatory state, the release of cytokines, the recruitment of peripheral immune cells, and a wide variety of other processes. Neuroinflammation has been implicated in nearly every major CNS disease ranging from Alzheimer's disease to brain cancer. Understanding and modeling neuroinflammation is critical for the identification of novel therapeutic targets in the treatment of CNS diseases. Unfortunately, the translation of findings from non-human models has left much to be desired. This review systematically discusses the role of human pluripotent stem cell (hPSC)-derived glia and supporting cells within the CNS, including astrocytes, microglia, oligodendrocyte precursor cells, pericytes, and endothelial cells, to describe the state of the field and hope for future discoveries. hPSC-derived cells offer an expanded potential to study the pathobiology of neuroinflammation and immunomodulatory cascades that impact disease progression. While much progress has been made in the development of models, there is much left to explore in the application of these models to understand the complex inflammatory response in the CNS.

Lipidomics of Huntington's Disease: A Comprehensive Review of Current Status and Future Directions

BACKGROUND

Huntington's disease (HD) is a multifaceted neurological disorder characterized by the progressive deterioration of motor, cognitive, and psychiatric functions. Despite a limited understanding of its pathogenesis, research has implicated abnormal trinucleotide cytosine-adenine-guanine CAG repeat expansion in the huntingtin gene (HTT) as a critical factor. The development of innovative strategies is imperative for the early detection of predictive biomarkers, enabling timely intervention and mitigating irreversible cellular damage. Lipidomics, a comprehensive analytical approach, has emerged as an indispensable tool for systematically characterizing lipid profiles and elucidating their role in disease pathology.

METHOD

A MedLine search was performed to identify studies that use lipidomics for the characterization of HD. Search terms included "Huntington disease"; "lipidomics"; "biomarker discovery"; "NMR"; and "Mass spectrometry".

RESULTS

This review highlights the significance of lipidomics in HD diagnosis and treatment, exploring changes in brain lipids and their functions. Recent breakthroughs in analytical techniques, particularly mass spectrometry and NMR spectroscopy, have revolutionized brain lipidomics research, enabling researchers to gain deeper insights into the complex lipidome of the brain.

CONCLUSIONS

A comprehensive understanding of the broad spectrum of lipidomics alterations in HD is vital for precise diagnostic evaluation and effective disease management. The integration of lipidomics with artificial intelligence and interdisciplinary collaboration holds promise for addressing the clinical variability of HD.

A review of the ethnomedicinal, phytochemical, and pharmacological properties of the Ferulago genus based on Structure-Activity Relationship (SAR) of coumarins

BACKGROUND

The Ferluago W.D.J. Koch genus includes 48 accepted perennial herbs that are distributed in the Mediterranean region, Southeast Europe, Central and Middle East of Asia. These plants are widely used in folk and conventional medicine due to their biological benefits such as anti-microbial, anti-inflammatory, anti-cancer, and immunomodulatory properties. Conducting a comprehensive review based on the structure activity relationships (SARs) of the coumarins, which has not been previously documented, can lead to a better insight into the genus Ferulago and its beneficial therapeutic activities.

METHODS

This review covers literature from 1969 to 2023, were collected from various scientific electronic databases to review phytochemical, pharmacological, and ethnopharmacological data of Ferulago species, as well as latest information on the SAR of reported coumarins from this genus.

RESULTS

Phytochemical studies showed that the biological actions of this genus are mediated by the reported specialized metabolites, such as coumarins and flavonoids. Simple coumarins, prenylated coumarins, furanocoumarins, and pyranocoumarins are the largest subclasses of coumarins found in diverse Ferulago species, which have discussed the biological effects of them with a focus on the Structure-Activity Relationship (SAR). For example, prenylated coumarins have shown potential leishmanicidal and anti-neuropsychiatric effects when substituted with a prenyl group at the 7-hydroxy, as well as the C6 and C8 positions in their scaffold. Similarly, furanocoumarins exhibit varied biological activities such as anti-inflammatory, anti-proliferative, and anti-convulsant effects. Modifying substitutions at the C5 and C6 positions in furanocoumarins can enhance these activities.

CONCLUSION

This study conducted a comprehensive review of all available information on the phytochemical and pharmacological characteristics of Ferulago species. Given the high occurrence of coumarins in this genus, which exhibit potential anti-Alzheimer and anti-microbial properties, it presents promising new therapeutic avenues for addressing these common issues. Further investigation is needed to understand the molecular-level mechanisms of action and to explore their clinical applications.

Value of preclinical systematic reviews and meta-analyses in pediatric research

Similar to systematic reviews (SRs) in clinical fields, preclinical SRs address a specific research area, furnishing information on current knowledge, possible gaps, and potential methodological flaws of study design, conduct, and report. One of the main goals of preclinical SRs is to identify aspiring treatment strategies and evaluate if currently available data is solid enough to translate to clinical trials or highlight the gaps, thus justifying the need for new studies. It is imperative to rigorously follow the methodological standards that are widely available. These include registration of the protocol and adherence to guidelines for assessing the risk of bias, study quality, and certainty of evidence. A special consideration should be made for pediatric SRs, clinical and preclinical, due to the unique characteristics of this age group. These include rationale for intervention and comparison of primary and secondary outcomes. Outcomes measured should acknowledge age-related physiological changes and maturational processes of different organ systems. It is crucial to choose the age of the animals appropriately and its possible correspondence for specific pediatric age groups. The findings of well-conducted SRs of preclinical studies have the potential to provide a reliable evidence synthesis to guide the design of future preclinical and clinical studies. IMPACT: This narrative review highlights the importance of rigorous design, conduct and reporting of preclinical primary studies and systematic reviews. A special consideration should be made for pediatric systematic reviews of preclinical studies, due to the unique characteristics of this age group.

Metabolomics: An Emerging "Omics" Platform for Systems Biology and Its Implications for Huntington Disease Research

Huntington's disease (HD) is a progressive, fatal neurodegenerative disease characterized by motor, cognitive, and psychiatric symptoms. The precise mechanisms of HD progression are poorly understood; however, it is known that there is an expansion of the trinucleotide cytosine-adenine-guanine (CAG) repeat in the Huntingtin gene. Important new strategies are of paramount importance to identify early biomarkers with predictive value for intervening in disease progression at a stage when cellular dysfunction has not progressed irreversibly. Metabolomics is the study of global metabolite profiles in a system (cell, tissue, or organism) under certain conditions and is becoming an essential tool for the systemic characterization of metabolites to provide a snapshot of the functional and pathophysiological states of an organism and support disease diagnosis and biomarker discovery. This review briefly highlights the historical progress of metabolomic methodologies, followed by a more detailed review of the use of metabolomics in HD research to enable a greater understanding of the pathogenesis, its early prediction, and finally the main technical platforms in the field of metabolomics.

Mapping strategies towards improved external validity in preclinical translational research

INTRODUCTION

Translation is about successfully bringing findings from preclinical contexts into the clinic. This transfer is challenging as clinical trials frequently fail despite positive preclinical results. Limited robustness of preclinical research has been marked as one of the drivers of such failures. One suggested solution is to improve the external validity of in vitro and in vivo experiments via a suite of complementary strategies.

AREAS COVERED

In this review, the authors summarize the literature available on different strategies to improve external validity in in vivo, in vitro, or ex vivo experiments; systematic heterogenization; generalizability tests; and multi-batch and multicenter experiments. Articles that tested or discussed sources of variability in systematically heterogenized experiments were identified, and the most prevalent sources of variability are reviewed further. Special considerations in sample size planning, analysis options, and practical feasibility associated with each strategy are also reviewed.

EXPERT OPINION

The strategies reviewed differentially influence variation in experiments. Different research projects, with their unique goals, can leverage the strengths and limitations of each strategy. Applying a combination of these approaches in confirmatory stages of preclinical research putatively increases the chances of success in clinical studies.

Challenging Future Generations: A Qualitative Study of Students' Attitudes toward the Transition to Animal-Free Innovations in Education and Research

In 2016, the Dutch government declared its commitment to phasing out animal experiments by 2025. Although a high number of animal experiments are still performed and the 2025 target will not be met, the commitment remains. Efforts are being made to identify levers that might foster the transition to animal-free science. Education has been found to play a key role in the future of animal-free science and young generations are increasingly seen as key stakeholders. However, their attitudes toward the transition to animal-free innovations have not been investigated. The present article focuses on the values and beliefs held by students, who in 2022, participated in the course 'Replacing Animal Testing' (RAT) Challenge, organized by a consortium of Dutch universities. Contextually, students' motivations to follow the course were investigated. The research was based on a qualitative study, including semi-structured interviews and a literature review. Our analysis of the findings revealed that students feel aligned with the social, ethical, and scientific reasons that support the transition to animal-free innovations. Moreover, the participants identified a series of regulatory, educational, cultural, and political obstacles to the transition that align with those identified in recent literature. From the discussion of these findings, we extrapolated six fundamental challenges that need to be addressed to foster the transition to animal-free science in an acceptable and responsible way.

Validated Preclinical Mouse Model for Therapeutic Testing against Multidrug-Resistant Pseudomonas aeruginosa Strains

The rise in infections caused by antibiotic-resistant bacteria is outpacing the development of new antibiotics. The ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species) are a group of clinically important bacteria that have developed resistance to multiple antibiotics and are commonly referred to as multidrug resistant (MDR). The medical and research communities have recognized that, without new antimicrobials, infections by MDR bacteria will soon become a leading cause of morbidity and death. Therefore, there is an ever-growing need to expedite the development of novel antimicrobials to combat these infections. Toward this end, we set out to refine an existing mouse model of pulmonary Pseudomonas aeruginosa infection to generate a robust preclinical tool that can be used to rapidly and accurately predict novel antimicrobial efficacy. This refinement was achieved by characterizing the virulence of a panel of genetically diverse MDR P. aeruginosa strains in this model, by both 50% lethal dose (LD₅₀) analysis and natural history studies. Further, we defined two antibiotic regimens (aztreonam and amikacin) that can be used as comparators during the future evaluation of novel antimicrobials, and we confirmed that the model can effectively differentiate between successful and unsuccessful treatments, as predicted by in vitro inhibitory data. This validated model represents an important tool in our arsenal to develop new therapies to combat MDR P. aeruginosa strains, with the ability to provide rapid preclinical evaluation of novel antimicrobials and support data from clinical studies during the investigational drug development process. IMPORTANCE The prevalence of antibiotic resistance among bacterial pathogens is a growing problem that necessitates the development of new antibiotics. Preclinical animal models are important tools to facilitate and speed the development of novel antimicrobials. Successful outcomes in animal models not only justify progression of new drugs into human clinical trials but also can support FDA decisions if clinical trial sizes are small due to a small population of infections with specific drug-resistant strains. However, in both cases the preclinical animal model needs to be well characterized and provide robust and reproducible data. Toward this goal, we have refined an existing mouse model to better predict the efficacy of novel antibiotics. This improved model provides an important tool to better predict the clinical success of new antibiotics.

Identifying Key Factors for Accelerating the Transition to Animal-Testing-Free Medical Science through Co-Creative, Interdisciplinary Learning between Students and Teachers

Even with the introduction of the replacement, reduction, refinement (the three Rs) approach and promising technological developments in animal-testing-free alternatives over the past two decades, a significant number of animal tests are still performed in medical science today. This article analyses which factors could accelerate the transition to animal-free medical science, applying the multi-level perspective (MLP) framework. The analysis was based on qualitative research, including a desk study (literature review and document analysis), lectures from experts, and nine online focus group sessions with experts on 26 July 2021. These were undertaken as part of an honours project between May and September 2021 to identify barriers, levers, and opportunities for accelerating this transition. The MLP framework identifies required changes at three levels: innovations and new practices (niche level), the current (bio)medical research system (regime level), and larger societal forces (landscape level). All three levels interact in a non-linear fashion. The model enabled us to identify many relevant factors influencing the transition to animal-testing-free medical science and enabled priority setting. Our findings supported the formulation of six "focus areas" to which stakeholders could devote efforts in order to accelerate the transition to animal-testing-free medical science: (1) thorough and translatable new approach methods (NAMs) for human-relevant medical research; (2) open science and sharing data; (3) targeted funding for NAMs; (4) implementing and modernising legislation for NAMs; (5) interdisciplinary education on animal-testing-free medical science; and (6) facilitating a shift in societal views, as this would be of benefit to both animals and humans. It is proposed that these focus areas should be implemented in parallel.

The instrumental role of operant paradigms in translational psychiatric research: Insights from a maternal immune activation model of schizophrenia risk

Rigorous behavioral analysis is essential to the translation of research conducted using animal models of neuropsychiatric disease. Here we discuss the use of operant paradigms within our lab as a powerful approach for exploring the biobehavioral bases of disease in the maternal immune activation rat model of schizophrenia. We have investigated a range of disease features in schizophrenia including abnormal perception of time, cognition, learning, motivation, and internal state (psychosis), providing complex insights into brain and behavior. Beyond simple phenotyping, implementing sophisticated operant procedures has been effective in delineating aspects of pathological behavior, identifying interacting pathologies, and isolating contributing mechanisms of disease. We provide comment on the strengths of operant techniques to support high-quality behavioral investigations in fundamental neuropsychiatric research.

Reproducibility, relevance and reliability as barriers to efficient and credible biomedical technology translation

Biomedical research accuracy and relevance for improving healthcare are increasingly identified as costly problems. Basic research data quality, reporting and methodology, and reproducibility are common factors implicated in this challenge. Preclinical models of disease and therapy, largely conducted in rodents, have known deficiencies in replicating most human conditions. Their translation to human results is acknowledged to be poor for decades. Clinical data quality and quantity is also recognized as deficient; gold standard randomized clinical trials are expensive. Few solid conclusions from clinical studies are replicable and many remain unpublished. The translational pathway from fundamental biomedical research through to innovative solutions handed to clinical practitioners is therefore highly inefficient and costly in terms of wasted resources, early claims from fundamental discoveries never witnessed in humans, and few new, improved solutions available clinically for myriad diseases. Improving this biomedical research strategy and resourcing for reliability, translational relevance, reproducibility and clinical impact requires careful analysis and consistent enforcement at both funding and peer review levels.

Advanced In Vitro Lung Models for Drug and Toxicity Screening: The Promising Role of Induced Pluripotent Stem Cells

The substantial socioeconomic burden of lung diseases, recently highlighted by the disastrous impact of the coronavirus disease 2019 (COVID-19) pandemic, accentuates the need for interventive treatments capable of decelerating disease progression, limiting organ damage, and contributing to a functional tissue recovery. However, this is hampered by the lack of accurate human lung research models, which currently fail to reproduce the human pulmonary architecture and biochemical environment. Induced pluripotent stem cells (iPSCs) and organ-on-chip (OOC) technologies possess suitable characteristics for the generation of physiologically relevant in vitro lung models, allowing for developmental studies, disease modeling, and toxicological screening. Importantly, these platforms represent potential alternatives for animal testing, according to the 3Rs (replace, reduce, refine) principle, and hold promise for the identification and approval of new chemicals under the European REACH (registration, evaluation, authorization and restriction of chemicals) framework. As such, this review aims to summarize recent progress made in human iPSC- and OOC-based in vitro lung models. A general overview of the present applications of in vitro lung models is presented, followed by a summary of currently used protocols to generate different lung cell types from iPSCs. Lastly, recently developed iPSC-based lung models are discussed.

Impaired discrimination of a subanesthetic dose of ketamine in a maternal immune activation model of schizophrenia risk

BACKGROUND

Animal models of psychiatric diseases suffer from a lack of reliable methods for accurate assessment of subjective internal states in nonhumans. This gap makes translation of results from animal models to patients particularly challenging.

AIMS/METHODS

Here, we used the drug-discrimination paradigm to allow rats that model a risk factor for schizophrenia (maternal immune activation, MIA) to report on the subjective internal state produced by a subanesthetic dose of the N-methyl-D-aspartate (NMDA) receptor antagonist ketamine.

RESULTS/OUTCOMES

The MIA rats' discrimination of ketamine was impaired relative to controls, both in the total number of rats that acquired and the asymptotic level of discrimination accuracy. This deficit was not due to a general inability to learn to discriminate an internal drug cue or internal state generally, as MIA rats were unimpaired in the learning and acquisition of a morphine drug discrimination and were as sensitive to the internal state of satiety as controls. Furthermore, the deficit was not due to a decreased sensitivity to the physiological effects of ketamine, as MIA rats showed increased ketamine-induced locomotor activity. Finally, impaired discrimination of ketamine was only seen at subanesthetic doses which functionally correspond to psychotomimetic doses in humans.

CONCLUSION

These data link changes in NMDA responses to the MIA model. Furthermore, they confirm the utility of the drug-discrimination paradigm for future inquiries into the subjective internal state produced in models of schizophrenia and other developmental diseases.

Are Animal Models Needed to Discover, Develop and Test Pharmaceutical Drugs for Humans in the 21st Century?

Despite many decades of research, much of which has focused on studies in animals, we humans continue to suffer from multiple diseases for which there are no cures or treatments [...].