A webinar, sponsored by Emulate and Genetic Engineering & Biotechnology News, took a hard look at the models academia, government, and pharmaceutical entities are using to study drug toxicity and how Emulate Organ-Chips, also called microphysiological systems (MPS), are producing promising results. 

While two-dimensional cell studies and animal models provide useful information, they fail to fully replicate the complexities of human biology. In rare cases, they even miss lethal toxicities. One horrific example is fialuridine, a hepatitis B medication that killed five study participants in 1993. Preclinical animal models failed to catch the drug’s effects on human livers. 

“The real problem is animal models don’t predict human response,” said Donald Ingber, MD, PhD, Founding Director of the Wyss Institute for Biologically Inspired Engineering and an Emulate co-founder and board member. 

In addition to the risk to patients, poor models have helped create a slow and expensive drug development process, in which new medicines can take 15 years and $2 billion to develop and 90% of new drug applications ultimately fail. 

For these and other reasons, researchers and drug developers are exploring how to make pre-clinical drug testing more human-relevant and believe Organ-Chips are necessary complements for other cell and animal models to provide more accurate safety and efficacy readouts. 

Emulate Organ-Chips are designed to better replicate specific biological environments. They can include tissue-tissue interfaces, blood flow, immune cell interactions, microbes and mechanical forces. 

This mechanical stimulation is a critical element, helping organize various tissues, noted Nathalie Sauvonnet, PhD, Research Director at Institut Pasteur. While studying the shigella pathogen, Dr. Sauvonnet was having trouble replicating the bacteria’s activity in a dish. However, an intestine-chip gave her team new insights. 

“We could reproduce the activity of shigella as seen in the human patient,” said Dr. Sauvonnet. 

William Proctor, PhD, Senior Director for Predictive Toxicology and Safety Assessment at Genentech, discussed how Organ-Chips have the potential to reduce the need for animal models. In addition to their inability to replicate drug toxicities in humans, animals are expensive to nurture. The industry is eager to find alternatives. 

Genentech has developed its own core facility (the Complex In Vitro Systems Laboratory) to advance Organ-Chips. “We know this is transformative technology,” said Dr. Proctor. “How we get there in drug discovery and development is tailored to each organization, but also how quickly we can get comfortable doing this internally.” 

Tyler Goralski, PhD, is testing MPS for chemical and biological defense. Dr. Goralski is a research biologist at the US Army’s DEVCOM Chemical Biological Center. He believes MPS can help him assess chemical agents before going into in vivo models. 

Speakers highlighted a wide variety of other MPS applications. Luke Dimasi, Senior Director of Product Management at Emulate, outlined their work using the Emulate Colon Intestine-Chip to study inflammatory bowel disease.  

Jordan Kerns, Director of Biological Science at Emulate, noted how Organ-Chips can provide better safety and efficacy data for T-cell bispecific antibodies – an exciting but potentially risky therapy.  

Another session described how neural chips can help dissect the mechanisms that make the brain a fertile place for Alzheimer’s and other neurodegenerative diseases. Anna Herland, PhD, Associate Professor, Biohybrid Systems at Kungliga Tekniska Högskolan and Karolinska Institutet, discussed how combining neural chips with induced pluripotent stem cell-derived endothelial cells, pericytes, astrocytes and neurons provided new insights into the crosstalk between brain cells and the blood brain barrier. 

Overall, the symposium painted a bright picture of how Organ-Chips can provide better safety and efficacy data to drive more efficient drug development. In particular, detecting toxicities that might go undiscovered using more traditional models. 

To drive that point home, Lorna Ewart, Executive Vice President of Science at Emulate, noted that current MPS technology would have caught fialuridine toxicity before it was administered to patients, avoiding a tragic outcome.  In case you missed the must-view event, you can watch it here.

As many as 90 percent of new drug compounds fall short in clinical trials. Many of them fail because the compounds are toxic in humans, particularly to the liver and kidneys. Though pharmaceutical companies use cell cultures and animal models to assess toxicity issues before their drugs go to human trials, those approaches have shown mixed success.  

This established preclinical workflow is wasteful on many levels. Drug companies expend precious resources on new drug applications that are doomed to failure. Clinical trial participants are often exposed to toxic compounds, and some have paid dearly. Patients hoping for more effective medicines must continue to wait. 

In an ideal world, pharma companies would fully understand a drug’s potential toxicities long before it goes to human trials. If the compound is found to have toxicity, medicinal chemists could alter the molecule to mitigate the problem. In other cases, resources could be shifted to drugs that have fewer toxic effects. 

To get there, we need to augment the preclinical workflow, leverage new models, and provide better data on drug toxicity with in vitro toxicology testing at the early stages of research and development. Organ-Chips are a promising option. 

The Advantages of Organ-Chips  

Emulate has developed liver and kidney chips that can provide truer readouts on drug toxicity. These small microfluidic chips, about the size of an AA battery, are designed to better replicate the forces and signals cells encounter in vivo. 

Kidney toxicity is a major reason therapeutic compounds fail in human trials. Toxicity often shows up in the renal proximal tubules, which are responsible for filtering the blood. The Emulate human Proximal Tubule Kidney-Chip was created to model this behavior. The chip contains both tubular and vascular endothelium to replicate mechanical and physiological forces in the body, such as cellular signaling and shear stress, and provide a model that will more accurately predict how these cells respond to medicines or other compounds.  

In addition, because organ-chips are made from a clear polymer, they can be visualized. For example, researchers can easily examine cellular morphology under a microscope.  

Emulate recently tested the Kidney-Chip against cisplatin and gentamycin, which are known nephrotoxic agents. The cells in the chip reacted to these toxins much like cells in the body, showing obvious injuries. In addition, by studying gene expression and other factors, Emulate researchers showed the chips reproduced cellular transporters, which play a significant role in toxicity, and other important kidney mechanisms. Ultimately, the study showed the chip offers a physiologically relevant way to assess drug safety. 

A Dynamic Preclinical Model

Instead of studying compounds on cell cultures, followed by animal models, followed by human participants, researchers can layer in this new model, which more closely replicates how cells behave in the body. Organ-Chips will not replace cell culture or animal models in the immediate future. Rather, they provide a vehicle to inform preclinical data and ultimately predict a drug’s potential toxicity. 

The goal is to catch toxicity much earlier in the process, a refinement that could reduce waste, giving pharma companies better data to decide which compounds move forward into new drug applications and which ones should be reexamined.   

Having this extra layer of data could ultimately make clinical trials more efficient, increasing success rates, reducing the dangers to trial participants and accelerating the drug discovery process. 

On March 10th, 2021 Rep. Alcee L. Hastings (D-Fla.) and Citizens for Alternatives to Animal Research (CAARE) hosted the “21st Century Alternatives to Animals in Biomedical Research” virtual briefing in support of the Humane Research and Testing Act, re-introduced by representatives Hastings and Vern Buchanan (R-Fla.). Attending staffers had the opportunity to hear from a variety of scientific and medical experts and renowned primatologist Jane Goodall about the need to explore alternatives to animal models for biomedical research. Don Ingber, Scientific Founder of Emulate, spoke about how organ-on-a-chip technology can overcome many of the scientific inadequacies and ethical concerns associated with animal models. Together, the speakers highlighted many opportunities to improve drug discovery that will come from creating a National Center for Alternatives to Research and Testing as part of NIH. The message was clear — the use of animal studies and testing is not only inhumane and expensive, but it also doesn’t produce human-relevant data. More compelling human-relevant testing solutions, like Emulate Organ-Chips, are now available.  

Dr. Jane Goodall, founder of the Jane Goodall Institute, began the briefing by recounting one of the “worst days of [her] life:” when she visited a laboratory in the 1980s that used chimpanzees as test subjects. Dr. Goodall stressed that animal testing foundationally violates the rights of animals by subjecting them to a life of captivity and testing that could induce pain and fear in them. “Animal models really aren’t the answer,” she said. 

In addition to their ethical implications, animal studies have proven themselves insufficient in addressing today’s complex public health concerns, according to Paul Locke, JD, DrPH, Associate Professor at the Johns Hopkins Bloomberg School of Public Health and affiliate of the Center for Alternatives to Animals. Locke discussed how more sophisticated testing techniques can better imitate human biological processes and will facilitate the development of novel drugs and therapies with improved accuracy and efficiency. He emphasized that “research has shown us that non-animal methods are definitely the way to go.” 

Emulate Scientific Founder and Board Member Don Ingber presented about the benefits of organ-on-a-chip technology in his capacity as the Director of the Wyss Institute for Biologically Inspired Engineering at Harvard University. He discussed how Organs-on-Chips can be a solution to the demonstrated need for sophisticated, human-focused modeling in biomedical research. He showed attendees animated models of the organ-on-a-chip models and videos of experiment data to demonstrate how organ-on-a-chip technology can replicate and illustrate human biological functions. 

One field that could especially benefit from non-animal research methods is cancer research. “Cancer treatment has remained paleolithic,” noted oncologist Anza Raza, MD, Chan Soon-Shiong Professor of Medicine and Director of the MDS Center at Columbia University and author of the book The First Cell: And the Human Costs of Pursuing Cancer to the Last. Dr. Raza described how cancer treatment has seen little change in approach since the 1970s with the rudimentary tools of surgery, chemotherapy and radiation. Expressing disgust for new cancer therapies which only work for a subset of patients and often only for a short time, she noted “95 percent of experimental drugs fail, and the other 5 percent should have failed.” Anza views inapplicable animal models as a primary reason for cancer treatment’s stunted progress. She stressed that human-oriented models need to be used to understand cancer and other human diseases.  

Finally, Thomas Hartung, MD, PhD, Professor at the Johns Hopkins Bloomberg School of Public Health and Director of the Center for Alternatives to Animals, closed the briefing by stating the importance of the NIH’s role in normalizing new research techniques, and funding research to spur their development and use. He also described the importance of training the next generation of biomedical researchers on the most effective and cutting-edge tools and research methods, which he saw as necessary to making animal models a thing of the past.   Please visit house.gov to find your Congressional representative and encourage him or her to support the Humane Research and Testing Act.

In developing new medicines, the pharmaceutical industry has relied on antiquated research paradigms, established in a different era when the collective human understanding of animal biology was very different. The limitations of animal models in research were somewhat known, but at the time, they were the best available tools for predicting drug safety and response before human trials. In the intervening years, research conducted, and data revealed have given us reason to question the status quo.   

Today, more human-relevant models, such as new organ-on-a-chip technologies, exist which can help researchers understand mechanisms of disease and drug action. Newer pharmaceutical advances which harness the human immune system, or human-specific biological factors, represent roughly 40 percent of the pharmaceutical pipeline.  Animal models simply don’t work in predicting human responses to many biologic medicines and vaccines, and they present a myriad of ethical concerns and geopolitical challenges.  

To improve drug discovery, a paradigm shift is needed. Governments need to invest in future-focused solutions and create pathways for regulators to approve safe and effective drugs based on a wider variety of human-relevant modeling methods. At Emulate, we believe that the Humane Research and Testing Act (HR 1744), recently introduced, is the first step toward that paradigm shift the pharmaceutical industry so desperately needs, and we are proud to give it our endorsement.  

The bipartisan legislation introduced into the U.S. House of Representatives by Rep. Alcee Hastings (D-Fla.) and Rep. Vern Buchanan (R-Fla.) would establish the National Center for Alternatives to Research and Testing under the National Institutes of Health. The new Center would be dedicated to increasing transparency and understanding regarding the use of animals in research and testing and would be focused on ultimately reducing the number of animals used in such practices. It would require the NIH to develop, fund and execute a plan to enumerate the number of animals used in biomedical research, and incentivize companies to use non-animal methods by educating and training scientists on human-relevant research methods.  

Emulate is proud to endorse this legislation as we believe it is an essential first step toward ensuring that human-relevant models play a larger role in biomedical research.  We applaud Rep. Hastings and Rep. Buchanan for their leadership on this issue, as well as Representatives Joyce Beatty (D-Ohio), Julia Brownley (D-Calif.), and Lucille Roybal-Allard (D-Calif.) who are original co-sponsors of the bill.

Earlier this week, The New York Times ran an article outlining the need to build a strategic monkey reserve to address shortages in rhesus monkeys that have arisen in the testing of COVID-19 vaccines. Shortages have arisen since the import of animals from China have been banned during the pandemic, causing prices of monkeys to skyrocket. But the article fails to address the real issue—it’s time to say, ‘enough is enough’ and begin to discourage the use of primates for drug testing. Our societal goal should be reducing the number of monkeys used and encouraging more innovative alternatives to primate testing, not breeding more laboratory animals to keep up with the high demand from drug developers. 

Beyond the obvious ethical concerns, animal testing has severe limitations in effectiveness, particularly for today’s novel biologic drugs and vaccines. Monkeys are not always capable of replicating human disease processes or drug response. Advances in biopharmaceutical research, including Organ-on-a-Chip technology, which recreates human biology in highly controlled lab settings, can more closely emulate human drug response. 

While animal testing may always play a role in some pharmaceutical testing, a strategic monkey reserve is not the answer. It’s our responsibility to explore alternatives. If better patient outcomes are the end game, we should encourage the use of technology that gets us there faster, and more humanely.   We are, however, starting to see progress from a policy perspective in recognizing the importance of new alternatives to primate (and other animals) testing. In 2020, Congressional Representatives Alcee L. Hastings (D-Florida) and Vern Buchanan (R-Florida) together introduced legislation that would help improve animal testing transparency, while incentivizing the study of more human-relevant testing methods. We hope that similar legislation is introduced into the new Congress, as we believe it is the first step towards replacing animal testing with new methods that can more effectively recreate human cellular responses.

Before a drug comes to market, it is subjected to rigorous tests to ensure its safety and efficacy. However, many standard safety tests for drug candidates involve rodent and non-rodent animal models which cannot always accurately predict which drugs might cause drug-induced liver injury (DILI) in humans. To increase predictive confidence ahead of clinical studies, a species-specific, multicellular, in vitro hepatotoxicity assay was developed, using our Liver-Chip, to characterize human toxicities, including responses that may have not been accurately predicted by animal models.

Research Area: Hepatotoxicity testing

Organisms: Human, dog, rat

Sample Types: Human, dog, rat Hepatocytes, liver sinusoidal endothelial cells, Kupffer cells, and hepatic stellate cells

Research Question: Can a multispecies Liver-Chip predict liver toxicity and inform human relevance of liver toxicities detected in animal studies?

Emulate Organs-on-Chips technology was used to create rat, dog, and human Liver-Chips. Primary rat, dog, or human hepatocytes were seeded in the upper parenchymal channel within an extracellular matrix (ECM) layer on top of an ECM-coated, porous membrane that separates the two parallel microchannels. Species-specific rat, dog, or human liver sinusoidal endothelial cells (LSECs), with or without Kupffer cells and/or stellate cells, were cultured on the opposite side in the lower vascular channel. These quadruple-cell chips were characterized by albumin secretion and Cytochrome P450 enzymatic activity prior to drug toxicity testing.

RESULTS

Studying species-specific drug toxicities
To explore whether the rat, dog or human liver chips could be used to predict species-specific DILI responses, the study evaluated hepatotoxic effects induced by bosentan, a dual endothelin receptor antagonist. Due to species differences in the bile salt export pump (BSEP) efflux transporter, bile salts accumulate within hepatocytes upon exposure to bosentan, causing cholestasis in humans, but not in rats or dogs. The results showed that the mechanisms of drug induced liver injury can be dissected using the Liver-Chip. 

Detection of diverse phenotypes of hepatotoxicity
The species-specific, quadruple cell Liver-Chips were tested with tool compounds that are known to cause different kinds of toxicity and provided insights into the drug mechanism of action. In brief, the experiments were designed to detect Kupffer cell depletion, and markers of steatosis and fibrosis, with the results suggesting that the Liver-Chip could be a useful model for predicting toxicities. In addition, candidate drugs that show hepatotoxicity in dog and rat models can be screened for potential risk assessment in the human quadruple cell Liver-Chip.

Towards a more accurate model for pre-clinical screening
One of the most difficult forms of hepatotoxicity to predict relates to DILI responses that are often missed during preclinical and early clinical testing. The human Liver-Chip was exposed to TAK-875, a G protein coupled receptor 40 agonist that was discontinued in phase 3 trials due to DILI in a few individuals. The experiments showed that continuous and prolonged exposure caused mitochondrial dysfunction, oxidative stress, formation of lipid droplets, and an innate immune response, all of which are harbingers of DILI for susceptible patients. These results highlight the advantage of the Liver-Chip for assessing the pathophysiological consequence of reactive metabolite formation, which has been strongly associated with DILI.

CONCLUSION

This study explores whether species-specific, in vitro hepatotoxicity assays using Liver-Chips can provide a greater understanding of the mechanisms of hepatotoxicity in animal models, which may lead to reduction in the number of animal studies to provide accurate risk assessment for drug candidates. The Liver-Chip detected diverse types of liver toxicity, including hepatocellular injury, steatosis, cholestasis, and fibrosis. The study has shown that species-specific Liver-Chips have potential future applications for hepatotoxicity testing, disease modeling, biomarker identification. This experimental approach could also be used to study whether toxicities observed in animal models are translatable to humans, and to understand human cellular variability with regards to drug response.  

REFERENCE

Jang, KJ et al. Reproducing human and cross-species drug toxicities using a Liver-Chip. Sci Transl Med 019 Nov 6;11(517).

A summary of the scientific paper published in Advanced Science, “Is it Time for Reviewer 3 to Request Human Organ Chip Experiments Instead of Animal Validation Studies?“

Animal studies are an old practice, going back to the ancient Greeks, continuing with William Harvey and others in the 16th and 17th centuries and gaining greater traction in the past 100 years. Animal models offer more complexity than simple cell cultures, though they fall short of human physiology. But even with their known shortcomings, animal studies have been the gold standard for preclinical research – until now. 

To a large degree, the preference for animal studies was by necessity. Preclinical animal models were the best available research tools. However, in recent years, microfluidic Organ-Chips and other technologies have begun to offer superior alternatives. Because they use human tissues – in some cases cultured from patients – they can more accurately recapitulate many of the mechanisms associated with human physiology and bring us closer to personalized medicine.  

As many as 90% of all drugs that enter human clinical trials fail to gain FDA approval. Sometimes they are not effective and often, they are just too toxic. Our preclinical models should be able to catch these deficits before the drugs reach patients. However, the current system produces human suffering and wastes valuable time – we must identify better approaches. 

THE PROMISE OF ORGAN-CHIPS 

Microfluidic Organ-Chips offer a superior model because they can be built with human tissues and incorporate key physiological components, such as a vasculature, tissue-tissue interfaces, circulating immune cells, and even a complex microbiome. Mechanical forces, such as those associated with breathing or peristalsis, can be replicated as well. Advanced fluidics bring in nutrients, remove waste, and permit mimicry of dynamic changes in drug levels over time, better recapitulating what patients experience in vivo. 

These chips are transparent and small, which means researchers can observe reactions continuously, in real time, through microscopes or more advanced systems – something that cannot be done in animal models.  

But most importantly, from a drug development standpoint, these chips have been proven to provide important windows into human physiology and provide greater insight into how specific cells and tissues respond to therapeutic molecules. For example, lung chips have replicated human COPD and non-small cell lung cancer. Organ-chips have also modeled intestines, blood-brain barrier, bone marrow, liver, kidneys and numerous other organs and tissues. 

Organ-Chips can be particularly useful when investigating human immune responses. Different species of mammals have different immune systems, which can make them ineffective models when studying vaccines, cancer immunotherapies or autoimmune disease treatments.

One chip, modeling a single organ system, can be quite powerful. But these devices also can be linked fluidically for multi-organ studies, creating even more sophisticated “body-on-chips” models. These systems can incorporate many of the complex inter-organ signaling mechanisms found in the human body – for example, pancreatic islet cells can talk to liver tissue. Investigators can even model many of the complexities associated with the reproductive system.

THE COST OF FAILURE

The computer industry has a saying – garbage in, garbage out – and that could easily be applied to the biopharmaceuticals drug development pipeline. Inadequate preclinical models translate into failed drugs. If this were a purely academic discussion, the industry could be forgiven for moving slowly. But these poor models have real world ramifications when ineffective and/or toxic drugs enter human trials where at best they fail to deliver hoped-for benefits or worse, cause patients physical harm.

Organ-Chips have proven themselves over and over, identifying toxicities that went previously undetected in animal studies but unfortunately showed up in human trials. In one instance, a Blood Vessel-Chip retrospectively revealed the faults in a monoclonal antibody therapy that led to blood clot formation in the lung. Unfortunately, the drug had already caused deaths in the human study.  

Better preclinical reads on efficacy and safety mean drugs that would have been likely to fail in human trials can be shelved or redesigned. Medicines that work best in subpopulations can be tested early in those populations, rather than failing in a large trial and being reapplied to the smaller group as a consolation prize. Ultimately, making the system more efficient could accelerate our ability to conduct successful clinical trials, dramatically reducing costs and bringing new therapies to patients faster.

But it’s not just about drugs that show promise in animal models and fail in humans. We must also assume there are molecules that fail in animals but are safe and effective in people. However, we approach this problem, it’s obvious we are leaving good drugs on the table.

This is not to say that Organ-Chips are perfect models. They have trouble replicating peripheral neurons, fat and other tissues, which could generate serious blind spots. More work needs to be done to help these emerging research tools better incorporate in vivo human physiology. And that’s really the point. We can no longer be satisfied with the flawed preclinical models that have produced such poor results. Under the current regime, unmet medical needs, such as Alzheimer’s disease, continue to be unmet, and patients, caregivers and communities suffer. Microfluidic Organ-Chips will not solve all these issues, but they will provide insights animal models do not and will ultimately bring a more rational approach to our preclinical discovery efforts.

The hallmarks of progressive neurodegenerative diseases—problems with mobility and coordination or lapses in memory—are sadly familiar to millions of people. As neurons and supporting cells of the central and peripheral nervous system die, symptoms progressively get worse and are ultimately fatal for many of those who suffer from conditions like Alzheimer’s, Parkinson’s, or amyotrophic lateral sclerosis (ALS). Although the precise genetic, cellular, and physiological causes of all progressive neurodegeneration are not fully understood, misregulated inflammation has been implicated in many of them.

The global healthcare burden of neurodegenerative diseases remains extraordinarily high. According to the American Journal of Managed Care (AJMC), in 2020 nearly 6 million Americans suffered from Alzheimer’s disease with the estimated cost of care at $305 billion. This cost is expected to increase to more than $1 trillion per year as the population ages and disease prevalence grows. Although biopharmaceutical companies are urgently working to develop successful therapies and treatments, clinical trial failure rates remain high — Alzheimer’s in particular has a 100% failure rate for disease-modifying therapies. The human brain and nervous system are notoriously complex, and many gaps in understanding the mechanisms of disease progression, drug action, toxicity, and pharmacokinetic profiles continue to plague preclinical research reliant on conventional in vitro cell culture and animal models. Despite vast amounts of resources invested in drug development, companies are struggling to streamline the process and bring safer, more effective treatments for neurodegenerative disease to market faster.

Technology Development: Animal and In Vitro Models for Neuroscience Research 

The use of animal models for neuroscience research has a long history, dating back to the work of Aristotle.  Looking at animal brains as proxies for human brains has yielded many important discoveries, including characterizing neural cell types and how they contribute to organ structure and function, defining developmental patterns, and studying the effects of aging and drugs. While there are many good animal models for examining toxicity, drug effects, or motor and sensory functions, distinct species differences between animals and humans have hindered successful translation of neurogenerative therapies to the clinic.

Over the past two decades, advances in in vitro cell culture have fueled a hopeful  new era in neurodegenerative disease research. Co-culture models that incorporate endothelial cells, astrocytes, and pericytes to mimic the blood-brain barrier (BBB) have been developed to examine uptake of drug candidates or examine potential toxicity or cellular injury. These two-dimensional systems are useful for simple experiments that have defined endpoints, but the cultures typically lack physiological complexity in cell type, structure, and dynamic forces, limiting their predictive value. Breakthroughs in induced pluripotent stem cell (iPSC) research in the mid-2000s paved the way for culturing and characterizing many specialized human neural cell types for the first time. Alongside these developments, three-dimensional models called organoids, derived from stem cells, emerged with features like advanced cell composition, differentiation, and tissue architecture. Brain organoids have tremendous potential for understanding the developmental patterns of cells and how they are affected by genetic and environmental factors implicated in disease. However, even the most advanced co-cultures and organoids fall short in modeling the neurovascular unit as they lack a functional vascular system and usually, the relevant cell types involved in signaling, transport, and immune recruitment. 

Despite these advances in in vitro culture, more predictive models that reduce translational failures from preclinical testing to the clinic are needed to speed therapeutic development for neurodegenerative conditions like Alzheimer’s.  

A More Predictive In Vitro Model of the Human Brain 

For researchers investigating neuroinflammatory disease and therapeutics, Organs-on-Chips technology can provide a better model of the human brain and help elucidate mechanisms of disease, the inner workings of the blood-brain barrier, drug toxicity, and drug efficacy. The Emulate Brain-Chip is under development as a comprehensive model of the neurovascular unit that incorporates cells from the human brain—including the BBB—in a dynamic microenvironment. This “Brain-on-a-Chip” features five human iPSC-derived and primary cell types (neurons, microglia, astrocytes, pericytes, and brain microvascular endothelial cells) in a dynamic, tunable microenvironment. This complex human model can support the co-culture and establishment of extensive interaction between human iPSC-derived neurons and primary glial cells (astrocytes and microglia) and reproduce key features of neuroinflammation after exposure to inflammatory stimuli. Human iPSC-derived brain endothelial cells are successfully maintained in the vascular channel of the Brain-Chip in the presence of fluidic shear stress, while exhibiting hallmark features of the human blood-brain barrier, such as development of tight junctions and minimal barrier permeability. Taken together, the co-culture of these cell types in a dynamic microenvironment results in improved functionality, stability, and in vivo-like gene expression. 

The Emulate Brain-Chip is the next step in predictive biological models for neurodegenerative disease research, enabling researchers to investigate the safety, efficacy, and BBB penetration of therapeutics in a comprehensive, human-relevant model. Clinical successes enabled by the Brain-Chip will bring much-needed hope to millions who are impacted by neurodegenerative diseases. 

Contact us today to learn more about how Organ-on-a-Chip technology can help you advance your neurodegenerative disease research.

For the better part of the last century, much biological research was built upon in vitro experiments—commonly, cells growing in a dish—with the assumption that results from these cultures may translate into insights that are relevant to humans. Because in vitro studies generally lack three-dimensional (3D) context, mechanical forces, cellular microenvironment, and multi‐organ physiology of whole organisms, many researchers are starting to question the clinical relevance of findings obtained with two-dimensional (2D) in vitro models.

Compounding this issue is that the physiological relevance of 2D in vitro results must be validated using animal studies. However, using animals in research is controversial, with evidence suggesting that data are often not of significant benefit to humans, and raises ethical concerns about animal welfare. Biopharmaceutical companies around the world are looking to reduce, refine and eventually replace animal models for preclinical drug development, toxicology studies and disease modeling to save time, reduce costs and be more predictive for clinical trials.

2D vs 3D Cell Culture: More Refined In Vitro Models

Cell culture technology overall has been slow to innovate, and progress has been incremental over the past 50 years, with several notable exceptions for challenging cell types and more complex experimental systems. Transwells commonly consist of compartments housing several cell types and/or soluble factors that are separated by one or more selective membranes. Incorporation of extracellular matrix, such as Matrigel, enables cells such as tissue-derived or pluripotent stem cells to grow in culture. The use of pluripotent stem cells, which can be coaxed into developing different lineages, has helped researchers work within more accurate models. Spheroid culture technology allows cells to grow together in suspension, recreating gradients within a three-dimensional structure. Further refinements create multicellular niches that replicate organoid structures. These experimental systems are often best suited for defined processes such as high-throughput screening, dosage studies, or cellular responses at the gene or protein level. Most also require specialty cell culture media and supplemental factors, as well as manual cell passaging steps that pose risks for contamination.

A More “Natural” 3D Cell Culture Model

Enter Emulate, poised to offset biopharma’s reliance on animal models and traditional cell culture with Organs-on-Chips (OOC) technology. Organ-Chips are engineered microphysiological systems (MPS)—dynamic models with defined composition at the cell, tissue, and organ level—allowing discovery of contributors to human physiology and pathophysiology. Organ-Chips offer an advantage over many MPS and organoid culture systems because they rely on microfluidics to mimic vascular perfusion, tissue–tissue interfaces, and other important mechanical cues, such as stretch to emulate breathing or intestinal peristalsis. As “living 3D cross-sections of the functional units of key organs,” experiments with Organ-Chips must be carefully designed around the right experimental questions and relevant endpoints. Researchers can also layer on complexity to these models in the form of soluble factors and different cell types (e.g., iPSC, epithelial, endothelial, connective tissue, immune, nerve, muscle, commensal or pathogenic microbes) to expand their models, which is usually not possible with animal studies.

Organ-Chips with different fluidic designs can be used with primary, patient‐derived or differentiated cells to gain insight into human‐relevant cellular and molecular mechanisms of pathogenesis, as well as drug response. These robust models can be probed using a wide array of analytical techniques including high resolution microscopy, flow cytometry, genomics, proteomics, metabolomics, and histological analysis. With future development of integrated electrical, chemical, mechanical, and optical sensors, real-time readouts of tissue barrier integrity, electrical activity, oxygen utilization, pH, and molecular transport could be obtained. Emulate Organ-Chips were even sent to the International Space Station for experiments on the physiology of microgravity. 

As Organs-on-Chips technology becomes a better replicate of living beings, more questions arise to define the parameters that need to be reproduced. Emulate OOC technology is being used by researchers around the world to better understand COVID-19 disease processes and to play a role in the development of new therapeutics. Whether on the earth or flying high above it, OOCs are setting a new standard for predicting how humans respond to medicines, chemicals, and foods with greater precision and control than conventional cell culture or animal-based testing methods. 

---

Cited: 

“Special Report on Animal Models: All In” Randall C. Willis, DDN News July/Aug 2020. 

“Is it Time for Reviewer 3 to Request Human Organ Chip Experiments Instead of Animal Validation Studies?”  Don Ingber, founding director of the Wyss Institute & Chair of Emulate Scientific Advisory Board. Advanced Science Oct 12, 2020. 

Emulate is proud to be playing an important role in establishing accurate in vitro SARS-CoV-2 models using our Lung-Chip platform.

Organ-Chips Aid in Search for a COVID-19 Vaccine

The research community and biopharmaceutical industry have mobilized with unprecedented speed against the COVID-19 pandemic. While significant progress has been made in the development of vaccines and new therapeutics, there is still much to learn about the intricacies of how SARS-CoV-2 interacts within the human body, including dramatic differences in how individuals respond to this infection. Unraveling the complexities of COVID-19 requires a multidisciplinary approach and the convergence of leading-edge human-relevant technologies. Emulate is proud to be playing an important role in understanding SARS-CoV-2 using our Organs-on-Chips technology platform.

Notably, Emulate has entered into a research collaboration with the FDA where our Lung-Chip will be used to evaluate the safety of COVID-19 vaccines and protective immunity against the virus.  This study will be led by the FDA’s Center for Biologics Evaluation and Research (CBER) and will seek to address one of the most critical questions regarding protective immunity: why individuals experience a wide spectrum of disease severity and what constitutes protection against future infection.

Organ-Chips provide a window into human biology, and our Lung-Chip is opening a panoramic view of how, where, and why SARS-CoV-2 infects the human body. With our new technology, we are able to bring better, rapid insights about human disease and more quickly and precisely predict human response to medicines.

This project is one of several COVID-related initiatives being conducted using our Organ-Chips, particularly our Lung-Chip, to better understand the mechanisms and disease process of SARS-CoV-2 infection. Organ-Chips are integrated within our Human Emulation System®, and they are living, microengineered environments that recreate the natural physiology and mechanical forces cells experience within the human body. Organ-Chips provide a window into human biology, and our Lung-Chip is opening a panoramic view of how, where, and why SARS-CoV-2 infects the human body. With our new technology, we are able to bring better, rapid insights about human disease and more quickly and precisely predict human response to medicines.  
 

Here’s a snapshot of how collaborators and researchers are applying our advanced Organs-on-Chips platform to unravel the mysteries of SARS-CoV-2.

• FDA awarded a new research contract to the University of Liverpool and global partners to sequence and analyze samples from humans and animals to create profiles of various coronaviruses, including SARS-CoV-2, which causes COVID-19. The study will also examine in vitro coronavirus models, such as Organs-on-Chips. This regulatory science project, awarded in collaboration with the National Institutes of Health, National Institute of Allergy and Infectious Diseases (NIH/NIAID), will hopefully help inform development and evaluation of medical countermeasures for COVID-19. This project will use the Emulate Lung-Chip.
• Queen Mary University of London is using the Emulate Lung-Chip for COVID-19 research by Prof. Daniel Pennington to understand the mechanisms of vascular dysfunction in severe cases of COVID-19. Emerging data show there is an early vascular component of COVID-19 where the endothelial cells lining blood vessels are disrupted. The unique epithelial-endothelial interface of our Lung-Chip makes this the most suitable model system for studying this aspect of COVID-19. Specifically, the Lung-Chip will be used to study the effect of plasma from healthy individuals and those with severe infections on endothelial cell function. Results from the study will further our understanding of why some individuals show greater disease susceptibility and will help in identification of new therapeutic targets. 
• École Polytechnique Fédérale de Lausanne (EPFL), under the direction of Dr. Vivek Thacker, is leading a project to use the Emulate Lung-Chip to model the individual steps in how SARS-CoV-2 attacks the lungs. In his initial findings, the unique epithelial-endothelial interface of the Emulate chip has enabled discovery of a driver of vascular damage. Following the addition of SARS-CoV-2 to the Lung-Chip, the virus first attacks epithelial cells and within a day, reaches the inner layer of endothelial cells. These infected endothelial cells produce high levels of IL-6, suggesting vascular damage is directly caused by endothelial infection, and only exacerbated by immune-mediated cytokine storms. 
• Leiden University Medical Center researchers are conducting a research program using the Emulate Lung-Chip to study the lung epithelium, the main cell type infected by SARS-CoV-2, and to develop a Fibrosis Lung-Chip. The team will investigate how epithelium obtained from different respiratory locations, from nose to alveoli, respond to SARS-CoV-2 infection to better understand how the current coronavirus infects the respiratory tract and leads to long-term lung damage.
• As part of the World Health Organization’s (WHO) Research and Development Blueprint response to the COVID-19 outbreak, the Emulate Lung-Chip was used to provide preclinical insights on the efficacy of hydroxychloroquine for COVID-19, with results currently on BioRxiv. Therapeutic candidates for many types of diseases may appear to show efficacy in conventional cell cultures which cannot be replicated in more complex, physiologically-relevant in vitro models. The same held true for a study of hydroxychloroquine. Within vero cell culture, hydroxychloroquine appeared to demonstrate anti-viral properties; however, when evaluated in the Lung-Chip, these in vitro effects were not observed.

Our team at Emulate is proud to collaborate with and support leading institutions and visionary researchers around the world to advance our understanding of COVID-19. This pandemic has created an “all hands-on deck” imperative. By coming together and sharing our expertise, we will be in the best position to emerge from this pandemic more rapidly and with a wealth of insight that can be applied to the next infectious disease threat that emerges.