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.

Our mission to improve human health is not limited to any race, gender, color, creed, or sexual orientation, and we cannot realize this mission without first acknowledging the inequities in our society and working towards racial equity and justice.

As a company, we believe the ongoing injustice of systemic racism and oppression in our society needs to be addressed. The deaths of George Floyd, Breonna Taylor, Tony McDade, Ahmaud Arbery, and Manuel Ellis—as well as the far too many unnamed Black men and women before them—are a tragedy and a result of centuries-old systemic oppression and racism that have hurt our nation and our Black communities.

As an organization, we stand with many others who honor the Black lives lost due to the devastating effects of racial inequality, racial injustice, and White supremacy. We are also united with common values as part of our company principles called “Being Human”—a set of guidelines created by our team to help us all work in harmony. At its core, “Being Human” is a shared belief that compassion, honesty, and empathy are essential in achieving healthy collaboration toward our mission. But we cannot fully realize this principle without acknowledging unequivocally that Black Lives Matter.

As an organization, we stand with many others who honor the Black lives lost due to the devastating effects of racial inequality, racial injustice, and White supremacy.

We realize that there is work to be done in order to address the rampant inequalities that permeate our society, and we are committing to doing our part.

This includes, but is not limited to:

1. From June 1, 2020 through December 31, 2020, we are pledging to match employee donations to the below local and national organizations:

   • Black Lives Matter Boston

   • UNCF Boston

   • NAACP Boston

   • Movement for Black Lives

   • Equal Justice Initiative

   • Know Your Rights Camp

2. We are working to create a more inclusive workplace so all Emulate employees feel safe, comfortable, and valued. This includes:

   • Ensuring our hiring and professional development policies to promote diversity and racial equity across our organization.

   • Implementing anti-racism education and trainings to our entire team with the help of outside diversity and inclusion professionals and anti-racism educators.

   • Ensuring there are anti-bias practices in our hiring process to proactively level the playing field for all candidates.

3. We are updating our time-off policies to support paid time-off for employees who choose to exercise their constitutional rights to protest or assemble for the sake of any social movement or gathering.  

This is just the beginning. Our work will be ongoing as we continue to learn and grow as an organization, and we are committed to taking action to bring an end to injustice and inequality.

Using a Human-Relevant Model

Shigella are bacteria that cause Shigellosis, a gastrointestinal disease inducing severe stomach cramps, fever, and diarrhea. The onset of symptoms can begin from 1-2 days of contact and results from the rapid invasion of the pathogen within intestinal epithelial cells, leading to the destruction of healthy human colon tissue. In developing countries, Shigellosis remains an important health threat and can lead to epidemics where sanitation is poor^[1]. Every year, Shigellosis kills hundreds of thousands of individuals, mostly children younger than the age of five^[2].

It is challenging to study this pathogen because Shigella infects only humans, resulting in colon infection. Therefore, small animal models, such as mice, cannot be used to study the disease.  Also, conventional cellular in vitro models, such as human polarized epithelial cells grown on transwells, fail to develop efficient infection. Thus, it has been difficult to study the inception of Shigella infection and understand how this pathogen interacts with the epithelial barrier at the tissue scale. For decades, the scientific community has been missing a reliable, consistent, and clinically relevant Shigella infection in a polarized intestinal epithelial monolayer.

Leveraging Organs-on-Chips technology from Emulate, researchers published a paper in Cell Host & Microbe, highlighting how a human Intestine-Chip can be used to test the infectivity of Shigella. The paper showcases a number of experimental approaches such as real-time imaging, tissue cross-section analysis, and conventional microbiology.

Creating the Intestine-Chip for Shigella Testing

First, the microenvironment of the human intestine was recreated by utilizing Organs-on-Chips technology to create an Intestine-Chip model. The chip itself is made of an elastomeric polymer which consists of a central channel separated horizontally by a flexible porous membrane; two hollow vacuum channels laterally frame the central channel. The application of cyclic vacuum within these lateral channels induces strain and stretching of the porous membrane that recreate peristaltic-like motions (in vivo-relevant mechanical forces). In order to support the culture of human colonic epithelial cells, Caco-2 cells were used, and the separating membrane was coated with extracellular matrix (ECM). To recreate the physiological microenvironment of the intestine, the seeded cells were exposed to continuous flow for 5-6 days to recreate the shear stress on the epithelial channel and cyclic mechanical strain to reproduce the peristaltic motions.

Cells grown under these conditions self-organized into villi-like structures interspaced by crypt-like invaginations. Confirming that the seeded Caco-2 cells were polarized and exhibited known differentiation markers (E-cadherin, villin, and FABP1-KRT20). Scanning electron microscopy (SEM) imaging also showed microvilli in the epithelial channel, a typical structural marker of differentiated and polarized enterocytes.

Next, in order to address whether Shigella flexneri could infect the human colon epithelium in the chip, a wild-type strain expressing GFP (Shigella-WT-GFP) in the intestinal lumen of the Intestine-Chip was introduced.

Human-Relevant Data

Shigella invasion was observed when only a few hundred bacteria were introduced into the intestinal lumen. The observation that only minimal loads were required for infection is consistent with data from the clinic. Given this correlation between in vivo and chip data, the approach in the chip allowed us to dissect the fundamentals mediating Shigella invasion at the tissue scale. In particular, identification that Shigella directly infect enterocytes from the epithelial channel, shifting the current paradigm about the early stage of invasion. Secondly, the study found that Shigella take advantage of the 3D topology of the tissue to populate specific areas in the colon tissue reminiscent of the human colon crypts. Finally, the design of the Intestine-Chip recreates the mechanical forces on the pathogen invasion and found that peristalsis is critical for specific stages of the infection process.

Most surprising was the observation that Shigella could directly infect enterocytes from the epithelial side (from the intestinal lumen) as expected in vivo with such efficiency and reproducibility.

Collaboration

This work is the result of a collaboration between the Unité de Pathogénie Microbienne Moléculaire and Biomaterials and Microfluidics Core Facility at Institut Pasteur and Emulate. It exemplifies how joining forces from different areas of expertise (engineering, microbiology, and bio-imaging) can reveal new avenues to better understand the mechanism of infection by enteroinvasive bacteria. It also helps advance our understanding of human disease, ultimately enabling the development of new therapeutics.

References:

[1] NIH: https://www.ncbi.nlm.nih.gov/books/NBK8038/

[2] CDC: https://www.cdc.gov/shigella/index.html

The most powerful technologies of the past 15 years have been revolutionary not only because of what they enable people to do, but also because they are easy-to-use.

We designed our Human Emulation System to embody this philosophy. It takes Organ-on-a-Chip technology—which has traditionally required specialized engineering knowledge—and integrates it with hardware and software apps. This Organ-Chip technology platform can be utilized in contemporary laboratory workflows and provides advanced automation so that researchers can run experiments repeatedly and robustly in a variety of environments.

The development of the Human Emulation System started with the creation of our first Organ-Chips at the Wyss Institute of Biologically Inspired Engineering. At the time, we knew that an Organ-Chip solution held enormous potential to provide a better understanding of human biology and disease. But we also knew that we had to build an Organ-Chip technology platform that users with different training could use in their labs.

Chip-S1™ Stretchable Chip

Organ-Chips are living, micro-engineered environments that recreate the natural physiology and mechanical forces that cells experience within the human body. They recreate human biology more accurately than animal models or other cell culture methods. Our Chip-S1™ Stretchable Chip—our first commercially available chip design—can be configured to emulate different organs, including lung, liver, intestine, kidney, and brain.

The microenvironment created within each Chip-S1 includes epithelial cells in the top channel and endothelial cells in the bottom channel. The top and bottom channels are separated by a porous, flexible membrane that allows for cell-to-cell communication that is similar to those that are found in the body. These two channels are fluidically independent and users can determine the rate of flow through the channels.

Pod-1™ Portable Module

Our Pod houses the chip, supplies media, and enables compatibility with microscopes and other standard laboratory analysis equipment. The design of the Pod allows Organ-Chips to be easily transported around the lab and placed on microscopes for imaging. The Pod’s reservoirs allow users to introduce nutrient media, precisely control dosing to test drugs or other compounds, and sample chip effluent.

Zoë-CM1™ Culture Module

Our Zoë Culture Module is designed to sustain the life of cells within our Organ-Chips. It provides the dynamic flow of media and the mechanical forces that help recreate the microenvironment cells experience in vivo. The instrument automates the precise conditions needed for simultaneous cell culture of up to 12 Organ-Chips.

The culture module enables independent control the flow rate of media through the top and bottom channels of the chips, as well as stretch parameters — including frequency and amplitude. Additionally, Zoë has automated algorithms to prime the fluidic channels of Pods with media, and programming to maintain the culture microenvironment for optimal cell performance.

Orb-HM1™ Hub Module

The Orb Hub Module provides a simple solution for installing and operating the Human Emulation System within the lab environment. It delivers a mix of 5% CO₂, vacuum stretch, and power from standard lab connections. It generates the 5% CO₂ supply gas to Zoë by combining air with an external 100% carbon dioxide supply or from a portable CO₂ canister.

Software Apps

Our team is developing a suite of apps that can be used to plan and execute experiments, analyze data, and foster collaboration between and among teams. This shared ecosystem of apps is also designed to help teams write, edit, and share protocols and standardize the data they create. What’s more, these apps help users visualize and interpret datasets to improve an understanding of human biology and disease.

RECREATING DRUG SIDE-EFFECTS USING ORGANS-ON-CHIPS

Maintenance of the fluidity of blood within the circulatory system is an important physiological process that is tightly regulated by the endothelial cells that line the blood vessels of the human body. The term thrombosis usually refers to pathological blood clotting that can manifest clinically in relation to dysfunction of the circulatory system. As more therapeutics have been developed, it has also become apparent that some drugs can contribute to the development of thrombosis, resulting in serious adverse events.

It is difficult, however, to predict drug-induced thrombosis using current pre-clinical cell culture and animal models, due to the dynamic nature of the flow of blood in the body and the complex molecular mechanisms that regulate drug interaction with different blood components of the human circulatory system.

Human-Relevant Models

In a paper published in Clinical Pharmacology and Therapeutics, a Blood Vessel-Chip was developed to test a compound, a monoclonal antibody called Hu5c8, that had been shown to cause unwanted thrombosis in humans. Hu5c8 displayed promise as a treatment for lupus, but was ultimately terminated during clinical trials due to unexpected thrombotic and cardiovascular events it caused in patients. Unfortunately, these life-threatening side effects were not discovered during preclinical testing due to a lack of human-relevant models that could predict them. Using the Blood Vessel-Chip, researchers detected for the first time the pro-thrombotic effects of Hu5c8 using one clinically relevant dose of this compound in combination with human blood samples, and the data generated were consistent with previous clinical findings.

What’s perhaps even more interesting is that although previous studies have shown that thrombosis can be recreated in vitro, these results were limited to imaging data, since the formation of the clot made it impossible to obtain soluble samples. But in recent work, a team of researchers created a new chip design that enabled the ability to sample and analyze biomarkers from a clotted chip, allowing insight into mechanism of action of how Hu5c8 led to thrombosis.

Efficacy Testing of Anti-Platelet Drugs

With this chip design, researchers could induce thrombosis by stimulating endothelial inflammation, or by adding blood-borne, pro-coagulant factors. This approach created the ability to study the efficacy of anti-platelet drugs and is highlighted in the paper published in collaboration with Janssen Research & Development, the Wyss Institute at Harvard, and the University of Twente. This research shows how Organs-on-Chips technology enables the use of human-relevant models of drug-induced thrombosis, helps us dissect the molecular mechanisms that mediate this process, and it could also be used to study the efficacy of new anti-thrombotic therapeutics.