Leveraging biomarkers and translational medicine for preclinical safety - Lessons for advancing the validation of alternatives to animal testing.

This article explores the potential of principles established in translational medicine for the use of bio-markers to advance the validation of alternatives to animal testing in preclinical safety assessment. It examines especially how such principles can enhance the predictive power, mechanistic under-standing, and human relevance of new approach methodologies (NAMs). Key concepts from translational medicine, such as fit-for-purpose validation, evidence-based approaches, and inte-grated testing strategies, are already being applied to the development and validation of NAMs. The article discusses challenges in implementing biomarker-based approaches, including standardi-zation, demonstration of relevance, regulatory acceptance, and addressing biological complexity. It also highlights opportunities for advancement through collaborative efforts, technological inno-vations, and regulatory evolution. Case studies demonstrate successful applications of biomarkers in preclinical safety, while future perspectives explore emerging trends like multi-omics integration, microphysiological systems, and artificial intelligence. The article emphasizes the potential of bio-markers and translational science approaches in creating more predictive, efficient, and ethical preclinical safety assessment paradigms in the use of NAMs. Use of biomarkers can enable the mechanistic validation of human-relevant models and provide a means to relate changes in NAMs to animal or clinical study results. By leveraging these tools, the field can work towards reducing reliance on animal testing while improving the accuracy and human relevance of safety predictions.

This article examines how biomarkers and translational science principles can improve safety testing without using animals. Biomarkers are quantifiable indicators of biological processes. Some of these can predict disease progression or drug effects. Translational science aims to apply laboratory findings towards clinical benefits. The article explores how combining these approaches can create better, more human-relevant and validated alternatives to animal testing. It discusses challenges that the field faces, including standardization of methods and getting regulatory acceptance. It also highlights opportunities, like integration with emerging technologies and increased global collabo­ration. The ultimate goal is to improve human health by streamlining NAM validation processes, i.e., show that new safety tests are more accurate, efficient, and ethical than current animal-based methods.

Engineering multicellular living systems-a Keystone Symposia report.

The ability to engineer complex multicellular systems has enormous potential to inform our understanding of biological processes and disease and alter the drug development process. Engineering living systems to emulate natural processes or to incorporate new functions relies on a detailed understanding of the biochemical, mechanical, and other cues between cells and between cells and their environment that result in the coordinated action of multicellular systems. On April 3-6, 2022, experts in the field met at the Keystone symposium "Engineering Multicellular Living Systems" to discuss recent advances in understanding how cells cooperate within a multicellular system, as well as recent efforts to engineer systems like organ-on-a-chip models, biological robots, and organoids. Given the similarities and common themes, this meeting was held in conjunction with the symposium "Organoids as Tools for Fundamental Discovery and Translation".

Pivoting Novel Exosome-Based Technologies for the Detection of SARS-CoV-2.

The National Institutes of Health (NIH) launched the Rapid Acceleration of Diagnostics (RADx) initiative to meet the needs for COVID-19 diagnostic and surveillance testing, and to speed its innovation in the development, commercialization, and implementation of new technologies and approaches. The RADx Radical (RADx-Rad) initiative is one component of the NIH RADx program which focuses on the development of new or non-traditional applications of existing approaches, to enhance their usability, accessibility, and/or accuracy for the detection of SARS-CoV-2. Exosomes are a subpopulation of extracellular vesicles (EVs) 30-140 nm in size, that are critical in cell-to-cell communication. The SARS-CoV-2 virus has similar physical and molecular properties as exosomes. Therefore, the novel tools and technologies that are currently in development for the isolation and detection of exosomes, may prove to be invaluable in screening for SARS-CoV-2 viral infection. Here, we describe how novel exosome-based technologies are being pivoted for the detection of SARS-CoV-2 and/or the diagnosis of COVID-19. Considerations for these technologies as they move toward clinical validation and commercially viable diagnostics is discussed along with their future potential. Ultimately, the technologies in development under the NIH RADx-Rad exosome-based non-traditional technologies toward multi-parametric and integrated approaches for SARS-CoV-2 program represent a significant advancement in diagnostic technology, and, due to a broad focus on the biophysical and biochemical properties of nanoparticles, the technologies have the potential to be further pivoted as tools for future infectious agents.

Microphysiological Systems: Stakeholder Challenges to Adoption in Drug Development.

Microphysiological systems (MPS) or tissue chips/organs-on-chips are novel in vitro models that emulate human physiology at the most basic functional level. In this review, we discuss various hurdles to widespread adoption of MPS technology focusing on issues from multiple stakeholder sectors, e.g., academic MPS developers, commercial suppliers of platforms, the pharmaceutical and biotechnology industries, and regulatory organizations. Broad adoption of MPS technology has thus far been limited by a gap in translation between platform developers, end-users, regulatory agencies, and the pharmaceutical industry. In this brief review, we offer a perspective on the existing barriers and how end-users may help surmount these obstacles to achieve broader adoption of MPS technology.

Microphysiological systems: What it takes for community adoption.

Microphysiological systems (MPS) are promising in vitro tools which could substantially improve the drug development process, particularly for underserved patient populations such as those with rare diseases, neural disorders, and diseases impacting pediatric populations. Currently, one of the major goals of the National Institutes of Health MPS program, led by the National Center for Advancing Translational Sciences (NCATS), is to demonstrate the utility of this emerging technology and help support the path to community adoption. However, community adoption of MPS technology has been hindered by a variety of factors including biological and technological challenges in device creation, issues with validation and standardization of MPS technology, and potential complications related to commercialization. In this brief Minireview, we offer an NCATS perspective on what current barriers exist to MPS adoption and provide an outlook on the future path to adoption of these in vitro tools.

Organs-on-chips: into the next decade.

Organs-on-chips (OoCs), also known as microphysiological systems or 'tissue chips' (the terms are synonymous), have attracted substantial interest in recent years owing to their potential to be informative at multiple stages of the drug discovery and development process. These innovative devices could provide insights into normal human organ function and disease pathophysiology, as well as more accurately predict the safety and efficacy of investigational drugs in humans. Therefore, they are likely to become useful additions to traditional preclinical cell culture methods and in vivo animal studies in the near term, and in some cases replacements for them in the longer term. In the past decade, the OoC field has seen dramatic advances in the sophistication of biology and engineering, in the demonstration of physiological relevance and in the range of applications. These advances have also revealed new challenges and opportunities, and expertise from multiple biomedical and engineering fields will be needed to fully realize the promise of OoCs for fundamental and translational applications. This Review provides a snapshot of this fast-evolving technology, discusses current applications and caveats for their implementation, and offers suggestions for directions in the next decade.

Organs-on-a-Chip.

Organs-on-chips, also known as "tissue chips" or microphysiological systems (MPS), are bioengineered microsystems capable of recreating aspects of human organ physiology and function and are in vitro tools with multiple applications in drug discovery and development. The ability to recapitulate human and animal tissues in physiologically relevant three-dimensional, multi-cellular environments allows applications in the drug development field, including; (1) use in assessing the safety and toxicity testing of potential therapeutics during early-stage preclinical drug development; (2) confirmation of drug/therapeutic efficacy in vitro; and (3) disease modeling of human tissues to recapitulate pathophysiology within specific subpopulations and even individuals, thereby advancing precision medicine efforts. This chapter will discuss the development and evolution of three-dimensional organ models over the past decade, and some of the opportunities offered by MPS technology that are not available through current standard two-dimensional cell cultures, or three-dimensional organoid systems. This chapter will outline future avenues of research in the MPS field, how cutting-edge biotechnology advances are expanding the applications for these systems, and discuss the current and future potential and challenges remaining for the field to address.

Biology-inspired microphysiological systems to advance patient benefit and animal welfare in drug development

The first microfluidic microphysiological systems (MPS) entered the academic scene more than 15 years ago and were considered an enabling technology to human (patho)biology in vitro and, therefore, provide alternative approaches to laboratory animals in pharmaceutical drug development and academic research. Nowadays, the field generates more than a thousand scientific publications per year. Despite the MPS hype in academia and by platform providers, which says this technology is about to reshape the entire in vitro culture landscape in basic and applied research, MPS approaches have neither been widely adopted by the pharmaceutical industry yet nor reached regulated drug authorization processes at all. Here, 46 leading experts from all stakeholders - academia, MPS supplier industry, pharmaceutical and consumer products industries, and leading regulatory agencies - worldwide have analyzed existing challenges and hurdles along the MPS-based assay life cycle in a second workshop of this kind in June 2019. They identified that the level of qualification of MPS-based assays for a given context of use and a communication gap between stakeholders are the major challenges for industrial adoption by end-users. Finally, a regulatory acceptance dilemma exists against that background. This t4 report elaborates on these findings in detail and summarizes solutions how to overcome the roadblocks. It provides recommendations and a roadmap towards regulatory accepted MPS-based models and assays for patients' benefit and further laboratory animal reduction in drug development. Finally, experts highlighted the potential of MPS-based human disease models to feedback into laboratory animal replacement in basic life science research.

Improved Ocular Tissue Models and Eye-On-A-Chip Technologies Will Facilitate Ophthalmic Drug Development.

In this study, we describe efforts by the National Eye Institute (NEI) and National Center for Advancing Translational Science (NCATS) to catalyze advances in 3-dimensional (3-D) ocular organoid and microphysiological systems (MPS). We reviewed the recent literature regarding ocular organoids and tissue chips. Animal models, 2-dimensional cell culture models, and postmortem human tissue samples provide the vision research community with insights critical to understanding pathophysiology and therapeutic development. The advent of induced pluripotent stem cell technologies provide researchers with enticing new approaches and tools that augment study in more traditional models to provide the scientific community with insights that have previously been impossible to obtain. Efforts by the National Institutes of Health (NIH) have already accelerated the pace of scientific discovery, and recent advances in ocular organoid and MPS modeling approaches have opened new avenues of investigation. In addition to more closely recapitulating the morphologies and physiological responses of in vivo human tissue, key breakthroughs have been made in the past year to resolve long-standing scientific questions regarding tissue development, molecular signaling, and pathophysiological mechanisms that promise to provide advances critical to therapeutic development and patient care. 3-D tissue culture modeling and MPS offer platforms for future high-throughput testing of therapeutic candidates and studies of gene interactions to improve models of complex genetic diseases with no well-defined etiology, such as age-related macular degeneration and Fuchs' dystrophy.

Extracellular RNAs as potential biomarkers for cancer.

The discovery that all cells secrete extracellular vesicles (EVs) to shuttle proteins and nucleic acids to recipient cells suggested they play an important role in intercellular communication. EVs are widely distributed in many body fluids, including blood, cerebrospinal fluid, urine and saliva. Exosomes are nano-sized EVs of endosomal origin that regulate many pathophysiological processes including immune responses, inflammation, tumour growth, and infection. Healthy individuals release exosomes with a cargo of different RNA, DNA, and protein contents into the circulation, which can be measured non-invasively as biomarkers of healthy and diseased states. Cancer-derived exosomes carry a unique set of DNA, RNA, protein and lipid reflecting the stage of tumour progression, and may serve as diagnostic and prognostic biomarkers for various cancers. However, many gaps in knowledge and technical challenges in EVs and extracellular RNA (exRNA) biology, such as mechanisms of EV biogenesis and uptake, exRNA cargo selection, and exRNA detection remain. The NIH Common Fund-supported exRNA Communication Consortium was launched in 2013 to address major scientific challenges in this field. This review focuses on scientific highlights in biomarker discovery of exosome-based exRNA in cancer and its possible clinical application as cancer biomarkers.

The NIH microphysiological systems program: developing in vitro tools for safety and efficacy in drug development.

Approximately 30% of drugs have failed in human clinical trials due to adverse reactions despite promising pre-clinical studies, and another 60% fail due to lack of efficacy. One of the major causes in the high attrition rate is the poor predictive value of current preclinical models used in drug development despite promising pre-clinical studies in 2-D cell culture and animal models. Microphysiological Systems or Tissue Chips are bioengineered microfluidic cell culture systems seeded with primary or stem cells that mimic the histoarchitecture, mechanics and physiological response of functional units of organs and organ systems. These platforms are useful tools for predictive toxicology and efficacy assessments of candidate therapeutics. Implementation of tissue chips in drug development requires effective partnerships with stakeholders, such as regulatory agencies, pharmaceutical companies, patient groups, and other government agencies. Tissue chips are also finding utility in studies in precision medicine, environmental exposures, reproduction and development, infectious diseases, microbiome and countermeasures agents.

Exploring Novel Biologically-Relevant Chemical Space Through Artificial Intelligence: The NCATS ASPIRE Program.

In recent years, artificial intelligence (AI)/machine learning (ML; a subset of AI) have become increasingly important to the biomedical research community. These technologies, coupled to big data and cheminformatics, have tremendous potential to improve the design of novel therapeutics and to provide safe and effective drugs to patients. A National Center for Advancing Translational Sciences (NCATS) program called A Specialized Platform for Innovative Research Exploration (ASPIRE) leverages advances in AI/ML, automated synthetic chemistry, and high-throughput biology, and seeks to enable translation and drug development by catalyzing exploration of biologically active chemical space. Here we discuss the opportunities and challenges surrounding the application of AI/ML to the exploration of novel biologically relevant chemical space as part of ASPIRE.

Microphysiological Systems (Tissue Chips) and their Utility for Rare Disease Research.

The scientific and technological development of microphysiological systems (MPS) modeling organs-on-chips, or "tissue chips" (TCs), has progressed rapidly over the past decade. Stem cell research and microfluidic concepts have combined to lead to the development of microphysiological platforms representing an ever-expanding list of different human organ systems. In the context of rare diseases, these bioengineered microfluidics platforms hold promise for modeling of disorders and could prove useful in the screening and efficacy testing of existing therapeutics. Additionally, they have the potential for replacing and refining animal use for new drugs and clinical treatments, or could even act as surrogate human systems for testing of new therapeutics in the future, which could be particularly useful in populations of rare disease sufferers. This chapter will discuss the current state of tissue chip research, and challenges facing the field. Additionally, we will discuss how these devices are being used to model basic cellular and molecular phenotypes of rare diseases, holding promise to provide new tools for understanding of disease pathologies and screening and efficacy testing of potential therapeutics for drug discovery.

Organs-on-chips: Progress, challenges, and future directions.

The National Institutes of Health Microphysiological Systems (MPS) program, led by the National Center for Advancing Translational Sciences, is part of a joint effort on MPS development with the Defense Advanced Research Projects Agency and with regulatory guidance from FDA, is now in its final year of funding. The program has produced many tangible outcomes in tissue chip development in terms of stem cell differentiation, microfluidic engineering, platform development, and single and multi-organ systems-and continues to help facilitate the acceptance and use of tissue chips by the wider community. As the first iteration of the program draws to a close, this Commentary will highlight some of the goals met, and lay out some of the challenges uncovered that will remain to be addressed as the field progresses. The future of the program will also be outlined. Impact statement This work is important to the field as it outlines the progress and challenges faced by the NIH Microphysiological Systems program to date, and the future of the program. This is useful information for the field to be aware of, both for current program stakeholders and future awardees and partners.

Facilitating the commercialization and use of organ platforms generated by the microphysiological systems (Tissue Chip) program through public-private partnerships.

Microphysiological systems (organs-on-chips, tissue chips) are devices designed to recapitulate human physiology that could be used to better understand drug responses not easily addressed using other in vivo systems or in vitro animal models. Although still in development, initial results seem promising as tissue chips exhibit in vivo systems-like functional responses. The National Center for Advancing Translation Science (NCATS) identifies this technology as a potential tool that could improve the process of getting safer, more effective treatments to patients, and has led to the Tissue Chip Program, which aims to develop, integrate and validate major organ systems for testing. In addition to organ chip development, NCATS emphasizes disseminating the technology to researchers. Commercialization has become an important issue, reflecting the difficulty of translation from discovery to adoption and wide availability. Therefore, NCATS issued a Request for Information (RFI) targeted to existing partnerships for commercializing tissue chips. The goal was to identify successes, failures and the best practices that could provide useful guidance for future partnerships aiming to make tissue chip technology widely available.

Biology-inspired microphysiological system approaches to solve the prediction dilemma of substance testing.

The recent advent of microphysiological systems - microfluidic biomimetic devices that aspire to emulate the biology of human tissues, organs and circulation in vitro - is envisaged to enable a global paradigm shift in drug development. An extraordinary US governmental initiative and various dedicated research programs in Europe and Asia have led recently to the first cutting-edge achievements of human single-organ and multi-organ engineering based on microphysiological systems. The expectation is that test systems established on this basis would model various disease stages, and predict toxicity, immunogenicity, ADME profiles and treatment efficacy prior to clinical testing. Consequently, this technology could significantly affect the way drug substances are developed in the future. Furthermore, microphysiological system-based assays may revolutionize our current global programs of prioritization of hazard characterization for any new substances to be used, for example, in agriculture, food, ecosystems or cosmetics, thus, replacing laboratory animal models used currently. Thirty-six experts from academia, industry and regulatory bodies present here the results of an intensive workshop (held in June 2015, Berlin, Germany). They review the status quo of microphysiological systems available today against industry needs, and assess the broad variety of approaches with fit-for-purpose potential in the drug development cycle. Feasible technical solutions to reach the next levels of human biology in vitro are proposed. Furthermore, key organ-on-a-chip case studies, as well as various national and international programs are highlighted. Finally, a roadmap into the future is outlined, to allow for more predictive and regulatory-accepted substance testing on a global scale.

Tissue Chips to aid drug development and modeling for rare diseases.

INTRODUCTION: The technologies used to design, create and use microphysiological systems (MPS, "tissue chips" or "organs-on-chips") have progressed rapidly in the last 5 years, and validation studies of the functional relevance of these platforms to human physiology, and response to drugs for individual model organ systems, are well underway. These studies are paving the way for integrated multi-organ systems that can model diseases and predict drug efficacy and toxicology of multiple organs in real-time, improving the potential for diagnostics and development of novel treatments of rare diseases in the future. AREAS COVERED: This review will briefly summarize the current state of tissue chip research and highlight model systems where these microfabricated (or bioengineered) devices are already being used to screen therapeutics, model disease states, and provide potential treatments in addition to helping elucidate the basic molecular and cellular phenotypes of rare diseases. EXPERT OPINION: Microphysiological systems hold great promise and potential for modeling rare disorders, as well as for their potential use to enhance the predictive power of new drug therapeutics, plus potentially increase the statistical power of clinical trials while removing the inherent risks of these trials in rare disease populations.