Creating an on-off switch to test stem cell therapy for Parkinson’s Disease

Sometimes you read about a new study where the researchers did something that just leaves you gob smacked. That’s how I felt when I read a study in the journal Cell Stem Cell about a possible new approach to helping people with Parkinson’s Disease (PD).

More on the gob smacking later. But first the reason for the study.

We know that one of the causes of Parkinson’s disease is the death of dopamine-producing neurons, brain cells that help plan and control body movement. Over the years, researchers have tried different ways to try and replace those cells but getting the cells where they need to be and getting them to integrate into the brain has proved challenging.

A team at the University of Wisconsin-Madison think they may have found a way to fix that. In an article in Drug Target Review  lead researcher Dr. Su-Chun Zhang, explained their approach:

“Our brain is wired in such an accurate way by very specialized nerve cells in particular locations so we can engage in all our complex behaviors. This all depends on circuits that are wired by specific cell types. Neurological injuries usually affect specific brain regions or specific cell types, disrupting circuits. In order to treat those diseases, we have to restore these circuits.”

The researchers took human embryonic stem cells and transformed them into dopamine-producing neurons, then they transplanted those cells into mice specially bred to display PD symptoms. After several months the team were able to show that not only had the mice improved motor skills but that the transplanted neurons were able to connect to the motor-control regions of the brain and also establish connections with regulatory regions of the brain, which prevented over stimulation. In other words, the transplanted cells looked and behaved the way they would in a healthy human brain.

Now here comes the gob smack part. The team wanted to make sure the cells they transplanted were the reason for the improved motor control in the mice. So, they had inserted a genetic on-and-off switch into the stem cells. By using specially designed drugs the researchers were able to switch the cells on or off.

When the cells were switched off the mice’s motor improvements stopped. When they were switched back on, they were restored.

Brilliant right! Well, I thought it was.

Next step is to test this approach in larger animals and, if all continues to look promising, to move into human clinical trials.

CIRM is already funding one clinical trial in Parkinson’s disease. You can read about it here.

Precision guided therapy from a patient’s own cells

Dr. Wesley McKeithan, Stanford

Imagine having a tool you could use to quickly test lots of different drugs against a disease to see which one works best. That’s been a goal of stem cell researchers for many years but turning that idea into a reality hasn’t been easy. That may be about to change.

A team of CIRM-funded researchers at the Stanford Cardiovascular Institute and the Human BioMolecular Research Institute in San Diego found a way to use stem cells from patients with a life-threatening heart disease, to refine an existing therapy to make it more effective, with fewer side effects.

The disease in question is called long QT syndrome (LQTS). This is a heart rhythm condition that can cause fast, chaotic heartbeats. Some people with the condition have seizures. In some severe cases, particularly in younger people, LQTS can cause sudden death.

There are a number of medications that can help keep LQTS under control. One of these is mexiletine. It’s effective at stabilizing the heart’s rhythm, but it also comes with some side effects such as stomach pain, chest discomfort, drowsiness, headache, and nausea.

The team wanted to find a way to test different forms of that medication to see if they could find one that worked better and was safer to take. So they used induced pluripotent stem cells (iPSCs) from patients with LQTS to do just that.

iPSCs are cells that are made from human tissue – usually skin – that can then be turned into any other cell in the body. In this case, they took tissue from people with LQTS and then turned them into heart cells called cardiomyocytes, the kind affected by the disease. The beauty of this technique is that even though these cells came from another source, they now look and act like cardiomyocytes affected by LQTS.

Dr. Mark Mercola, Stanford

In a news release Stanford’s Dr. Mark Mercola, the senior author of the study, said using these kinds of cells gave them a powerful tool.

“Drugs for heart disease are typically developed using overly simplified models, like tumor cells engineered in a specific way to mimic a biochemical event. Consequently, drugs like this one, mexiletine, have undesirable properties of concern in treating patients. Here, we used cells from a patient to generate that person’s heart muscle cells in a dish so we could visualize both the good and bad effects of the drug.”

The researchers then used these man-made cardiomyocytes to test various drugs that were very similar in structure to mexiletine. They were looking for ones that could help stabilize the heart arrhythmia but didn’t produce the unpleasant side effects. And they found some promising candidates.

Study first author, Dr. Wesley McKeithan, says the bigger impact of the study is that they were able to show how this kind of cell from patients with a particular disease can be used to “guide drug development and identify better drug improvement and optimization in a large-scale manner.”

 “Our approach shows the feasibility of introducing human disease models early in the drug development pipeline and opens the door for precision drug design to improve therapies for patients.”

The study is published in the journal Cell Stem Cell.

Super charging killer cells to fight leukemia

Colorized scanning electron micrograph of a natural killer cell.
Photo credit: National Institute of Allergy and Infectious Diseases

Racing car drivers are forever tinkering with their cars, trying to streamline them and soup up their engines because while fast is good, faster is better. Researchers do the same things with potential anti-cancer therapies, tinkering with them to make them safer and more readily available to patients while also boosting their ability to fight cancer.

That’s what researchers at the University of California San Diego (UCSD), in a CIRM-funded study, have done. They’ve taken immune system cells – with the already impressive name of ‘natural killer’ (NK) cells – and made them even deadlier to cancers.

These natural killer (NK) cells are considered one of our immune system’s frontline weapons against outside threats to our health, things like viruses and cancer. But sometimes the cancers manage to evade the NKs and spread throughout the body or, in the case of leukemia, throughout the blood.

Lots of researchers are looking at ways of taking a patient’s own NK cells and, in the lab boosting their ability to fight these cancers. However, using a patient’s own cells is both time consuming and very, very expensive.

Dan Kaufman MD

Dr. Dan Kaufman and his team at UCSD decided it would be better to try and develop an off-the-shelf approach, a therapy that could be mass produced from a single batch of NK cells and made available to anyone in need.

Using the iPSC method (which turns tissues like skin or blood into embryonic stem cell-like cells, capable of becoming any other cell in the body) they created a line of NK cells. Then they removed a gene called CISH which slows down the activities of cytokines, acting as a kind of brake or restraint on the immune system.

In a news release, Dr. Kaufman says removing CISH had a dramatic effect, boosting the power of the NK cells.

“We found that CISH-deleted iPSC-derived NK cells were able to effectively cure mice that harbor human leukemia cells, whereas mice treated with the unmodified NK cells died from the leukemia.”

Dr. Kaufman says the next step is to try and develop this approach for testing in people, to see if it can help people whose disease is not responding to conventional therapies.

“Importantly, iPSCs provide a stable platform for gene modification and since NK cells can be used as allogeneic cells (cells that come from donors) that do not need to be matched to individual patients, we can create a line of appropriately modified iPSC-derived NK cells suitable for treating hundreds or thousands of patients as a standardized, ‘off-the-shelf’ therapy.”

The study is published in the journal Cell Stem Cell.

Promising results from CIRM-funded projects

Severe Leukocyte Adhesion Deficiency-1 (LAD-1) is a rare condition that causes the immune system to malfunction and reduces its ability to fight off viruses and bacteria. Over time the repeated infections can take a heavy toll on the body and dramatically shorten a person’s life. But now a therapy, developed by Rocket Pharmaceuticals, is showing promise in helping people with this disorder.

The therapy, called RP-L201, targets white blood cells called neutrophils which ordinarily attack and destroy invading particles. In people with LAD-1 their neutrophils are dangerously low. That’s why the new data about this treatment is so encouraging.

In a news release, Jonathan Schwartz, M.D., Chief Medical Officer of Rocket, says early results in the CIRM-funded clinical trial, show great promise:

“Patients with severe LAD-I have neutrophil CD18 expression of less than 2% of normal, with extremely high mortality in early childhood. In this first patient, an increase to 47% CD18 expression sustained over six months demonstrates that RP-L201 has the potential to correct the neutrophil deficiency that is the hallmark of LAD-I. We are also pleased with the continued visible improvement of multiple disease-related skin lesions. The second patient has recently been treated, and we look forward to completing the Phase 1 portion of the registrational trial for this program.”

The results were released at the 23rd Annual Meeting of the American Society of Gene and Cell Therapy.

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These microscopic images show gene expression in muscle stem and progenitor cells as they mature from early development to adulthood (left to right). As part of this process, the cells switch from actively expressing one key gene (green) to another (violet); this is accompanied by the growth of muscle fibers (red).
Photo courtesy: Cell Stem Cell/UCLA Broad Stem Cell Research Center

When you are going on a road-trip you need a map to help you find your way. It’s the same with stem cell research. If you are going to develop a new way to treat devastating muscle diseases, you need to have a map to show you how to build new muscle stem cells. And that’s what researchers at the Eli and Edythe Broad Center for Regenerative Medicine and Stem Cell Research at UCLA – with help from CIRM funding – have done.

The team took muscle progenitor cells – which show what’s happening in development before a baby is born – and compared them to muscle stem cells – which control muscle development after a baby is born. That enabled them to identify which genes are active at what stage of development.

In a news release, April Pyle, senior author of the paper, says this could open the door to new therapies for a variety of conditions:

“Muscle loss due to aging or disease is often the result of dysfunctional muscle stem cells. This map identifies the precise gene networks present in muscle progenitor and stem cells across development, which is essential to developing methods to generate these cells in a dish to treat muscle disorders.”

The study is published in the journal Cell Stem Cell.

Rare Disease, Type 1 Diabetes, and Heart Function: Breakthroughs for Three CIRM-Funded Studies

This past week, there has been a lot of mention of CIRM funded studies that really highlight the importance of the work we support and the different disease areas we make an impact on. This includes important research related to rare disease, Type 1 Diabetes (T1D), and heart function. Below is a summary of the promising CIRM-funded studies released this past week for each one of these areas.

Rare Disease

Comparison of normal (left) and Pelizaeus-Merzbacher disease (PMD) brains (right) at age 2. 

Pelizaeus-Merzbacher disease (PMD) is a rare genetic condition affecting boys. It can be fatal before 10 years of age and symptoms of the disease include weakness and breathing difficulties. PMD is caused by a disruption in the formation of myelin, a type of insulation around nerve fibers that allows electrical signals in the brain to travel quickly. Without proper signaling, the brain has difficulty communicating with the rest of the body. Despite knowing what causes PMD, it has been difficult to understand why there is a disruption of myelin formation in the first place.

However, in a CIRM-funded study, Dr. David Rowitch, alongside a team of researchers at UCSF, Stanford, and the University of Cambridge, has been developing potential stem cell therapies to reverse or prevent myelin loss in PMD patients.

Two new studies, of which Dr. Rowitch is the primary author, published in Cell Stem Cell, and Stem Cell Reports, respectively report promising progress in using stem cells derived from patients to identify novel PMD drugs and in efforts to treat the disease by directly transplanting neural stem cells into patients’ brains. 

In a UCSF press release, Dr. Rowitch talks about the implications of his findings, stating that,

“Together these studies advance the field of stem cell medicine by showing how a drug therapy could benefit myelination and also that neural stem cell transplantation directly into the brains of boys with PMD is safe.”

Type 1 Diabetes

Viacyte, a company that is developing a treatment for Type 1 Diabetes (T1D), announced in a press release that the company presented preliminary data from a CIRM-funded clinical trial that shows promising results. T1D is an autoimmune disease in which the body’s own immune system destroys the cells in the pancreas that make insulin, a hormone that enables our bodies to break down sugar in the blood. CIRM has been funding ViaCyte from it’s very earliest days, investing more than $72 million into the company.

The study uses pancreatic precursor cells, which are derived from stem cells, and implants them into patients in an encapsulation device. The preliminary data showed that the implanted cells, when effectively engrafted, are capable of producing circulating C-peptide, a biomarker for insulin, in patients with T1D. Optimization of the procedure needs to be explored further.

“This is encouraging news,” said Dr. Maria Millan, President and CEO of CIRM. “We are very aware of the major biologic and technical challenges of an implantable cell therapy for Type 1 Diabetes, so this early biologic signal in patients is an important step for the Viacyte program.”

Heart Function

Although various genome studies have uncovered over 500 genetic variants linked to heart function, such as irregular heart rhythms and heart rate, it has been unclear exactly how they influence heart function.

In a CIRM-funded study, Dr. Kelly Frazer and her team at UCSD studied this link further by deriving heart cells from induced pluripotent stem cells. These stem cells were in turn derived from skin samples of seven family members. After conducting extensive genome-wide analysis, the team discovered that many of these genetic variations influence heart function because they affect the binding of a protein called NKX2-5.

In a press release by UCSD, Dr. Frazer elaborated on the important role this protein plays by stating that,

“NKX2-5 binds to many different places in the genome near heart genes, so it makes sense that variation in the factor itself or the DNA to which it binds would affect that function. As a result, we are finding that multiple heart-related traits can share a common mechanism — in this case, differential binding of NKX2-5 due to DNA variants.”

The full results of this study were published in Nature Genetics.

Engineered T cells made from stem cells could provide immunity against multiple cancers

Dr. Lily Yang

Within all of our bodies there is a special type of “super” immune cell that holds enormous potential. Unlike regular immune cells that can only attack one cancer at a time, these “super” immune cells have the ability to target many types of cancers at once. These specialized cells are known as invariant natural killer T cells or iNKT cells for short. Unfortunately, there are relatively few of these cells normally present in the body.

However, in a CIRM-funded study, Dr. Lily Yang and her team of researchers at UCLA have found a way to produce iNKT cells from human blood stem cells. They were then able to test these iNKT cells on mice with both human bone marrow and human cancers. These mice either had multiple melanoma, a type of blood cancer, or melanoma, a solid tumor cancer. The researchers then studied what happened to mice’s immune system, cancers, and engineered iNKT cells after they had integrated into the bone marrow.

The results were remarkable. The team found that the blood stem cells now differentiated normally into iNKT cells, producing iNKT cells for the rest of the animal’s life, which was generally about a year. Mice without the engineered stem cell transplants had undetectable levels of iNKT cells while those that received the engineered cells had iNKT cells make up as much as 60% of the total immune system cells. The team also found that the engineered iNKT cells were able to suppress tumor growth in both multiple myeloma and melanoma.

Dr. Yang, in a press release by UCLA health, discussed the significance of the results in this animal model and the enormous potential this could have for cancer patients.

“What’s really exciting is that we can give this treatment just once and it increases the number of iNKT cells to levels that can fight cancer for the lifetime of the animals.” said Yang.

In the same press release, Dr. Yang continued to highlight the study’s importance by saying that,

“One advantage of this approach is that it’s a one-time cell therapy that can provide patients with a lifelong supply of iNKT cells.”

Researchers mentioned that they could control total iNKT cell make up in the immune system depending on how they engineered the blood stem cells. However, more research is needed to determine how these engineered iNKT cells might be useful for treating cancer in humans and evaluating any long-term side effects associated with an increased number of these cells.

The full results of this study were published in the journal Cell Stem Cell.

Scientists at USC untangle the mysteries of cellular reprogramming- a method that could be used to treat diseases

Dr. Justin Ichida, Assistant Professor at USC and lead author of the study

Scientists have long tried to repurpose cells in order to potentially treat various types of conditions. This process, called reprogramming, involves changing one type of cell into another, such as a blood cell into a muscle cell or nerve cell. Although the technique has been around for decades, it has only been effective 1% of the time.

Fortunately, thanks in part to a CIRM grant, Dr. Justin Ichida and other researchers at USC have been able to untangle this complicated process to ensure reprogramming happens more efficiently. The researchers were able to figure out a process that reprograms cells much more reliably than previous methods.

USC scientists have found a solution to untangle twisty DNA, removing kinks so the molecules can be used to reprogram cells to advance regenerative medicine to treat disease.
Photo courtesy of Illustration/iStock

The technique the scientists developed uses an enzyme to untangle reprogramming DNA, similar to how a hairdresser conditions untangled hair. Since DNA molecules are twisty by nature, due to the double helix configuration, they do not respond well when manipulated to change itself. Therefore, reprogramming DNA requires uncoiling, yet when scientists begin to unravel the molecules, they knot up tighter.

“Think of it as a phone cord, which is coily to begin with, then gets more coils and knots when something is trying to harm it,” Dr. Ichida said in a press release by USC.

To smooth the kinks, the researchers treated cells with a chemical and genetic cocktail that activates enzymes that open up the DNA molecules. This process releases the coiled tension and lays out the DNA smoothly, leading to more efficient cellular reprogramming.

This new technique works almost 100% of the time and has been proven in human and mouse cells. The increased efficiency of this techniques opens the possibilities for studying disease development and drug treatments. New cells could be created to replace lost cells or acquire cells that can’t be extracted from people, a problem observed in Parkinson’s, ALS, and other neurological diseases.

Moreover, since these reprogrammed cells are the same age as the parent cell, they could be used to better understand age-related diseases. It is possible that the reprogrammed cells may be better at creating age-accurate models of human disease, which are useful to study a wide array of degenerative diseases and accelerated aging syndromes.

To summarize his work, Dr. Ichida states in the USC press release that,

“A modern approach for disease studies and regenerative medicine is to induce cells to switch their identity. This is called reprogramming, and it enables the attainment of inaccessible tissue types from diseased patients for examination, as well as the potential restoration of lost tissue. However, reprogramming is extremely inefficient, limiting its utility. In this study, we’ve identified the roadblock that prevents cells from switching their identity. It turns out to be tangles on the DNA within cells that form during the reprogramming process. By activating enzymes that untangle the DNA, we enable near 100% reprogramming efficiency.”

The full findings of this study can be found in Cell Stem Cell.

“Brains” in a dish that can create electrical impulses

Brain organoids in a petri dish: photo courtesy UCSD

For several years, researchers have been able to take stem cells and use them to make three dimensional structures called organoids. These are a kind of mini organ that scientists can then use to study what happens in the real thing. For example, creating kidney organoids to see how kidney disease develops in patients.

Scientists can do the same with brain cells, creating clumps of cells that become a kind of miniature version of parts of the brain. These organoids can’t do any of the complex things our brains do – such as thinking – but they do serve as useful physical models for us to use in trying to develop a deeper understanding of the brain.

Now Alysson Muotri and his team at UC San Diego – in a study supported by two grants from CIRM – have taken the science one step further, developing brain organoids that allow us to measure the level of electrical activity they generate, and then compare it to the electrical activity seen in the developing brain of a fetus. That last sentence might cause some people to say “What?”, but this is actually really cool science that could help us gain a deeper understanding of how brains develop and come up with new ways to treat problems in the brain caused by faulty circuitry, such as autism or schizophrenia.

The team developed new, more effective methods of growing clusters of the different kinds of cells found in the brain. They then placed them on a multi-electrode array, a kind of muffin tray that could measure electrical impulses. As they fed the cells and increased the number of cells in the trays they were able to measure changes in the electrical impulses they gave off. The cells went from producing 3,000 spikes a minute to 300,000 spikes a minute. This is the first time this level of activity has been achieved in a cell-based laboratory model. But that’s not all.

When they further analyzed the activity of the organoids, they found there were some similarities to the activity seen in the brains of premature babies. For instance, both produced short bursts of activity, followed by a period of inactivity.

Alysson Muotri

In a news release Muotri says they were surprised by the finding:

“We couldn’t believe it at first — we thought our electrodes were malfunctioning. Because the data were so striking, I think many people were kind of skeptical about it, and understandably so.”

Muotri knows that this research – published in the journal Cell Stem Cell – raises ethical issues and he is quick to say that these organoids are nothing like a baby’s brain, that they differ in several critical ways. The organoids are tiny, not just in size but also in the numbers of cells involved. They also don’t have blood vessels to keep them alive or help them grow and they don’t have any ability to think.

“They are far from being functionally equivalent to a full cortex, even in a baby. In fact, we don’t yet have a way to even measure consciousness or sentience.”

What these organoids do have is the ability to help us look at the structure and activity of the brain in ways we never could before. In the past researchers depended on mice or other animals to test new ideas or therapies for human diseases or disorders. Because our brains are so different than animal brains those approaches have had limited results. Just think about how many treatments for Alzheimer’s looked promising in animal models but failed completely in people.

These new organoids allow us to explore how new therapies might work in the human brain, and hopefully increase our ability to develop more effective treatments for conditions as varied as epilepsy and autism.

Stanford study successful in transplant of mismatched stem cells, tissue in mice

Dr. Irv Weissman at Stanford University

A transplant can be a lifesaving procedure for many people across the United States. In fact, according to the Health Resources & Services Administration, 36,528 transplants were performed in 2018. However, as of January 2019, the number of men, women, and children on the national transplant waiting list is over 113,000, with 20 people dying each day waiting for a transplant and a new person being added to the list every 10 minutes.

Before considering a transplant, there needs to be an immunological match between the donated tissue and/or blood stem cells and the recipient. To put it simply, a “match” indicates that the donor’s cells will not be marked by the recipient’s immune cells as foreign and begin to attack it, a process known as graft-versus-host disease. Unfortunately, these matches can be challenging to find, particularly for some ethnic minorities. Often times, immunosuppression drugs are also needed in order to prevent the foreign cells from being attacked by the body’s immune system. Additionally, chemotherapy and radiation are often needed as well.

Fortunately, a CIRM-funded study at Stanford has shown some promising results towards addressing the issue of matching donor cells and recipient. Dr. Irv Weissman and his colleagues at Stanford have found a way to prepare mice for a transplant of blood stem cells, even when donor and recipient are an immunological mismatch. Their method involved using a combination of six specific antibodies and does not require ongoing immunosuppression.

The combination of antibodies did this by eliminating several types of immune cells in the animals’ bone marrow, which allowed blood stem cells to engraft and begin producing blood and immune cells without the need for continued immunosuppression. The blood stem cells used were haploidentical, which, to put it simply, is what naturally occurs between parent and child, or between about half of all siblings. 

Additional experiments also showed that the mice treated with the six antibodies could also accept completely mismatched purified blood stem cells, such as those that might be obtained from an embryonic stem cell line. 

The results established in this mouse model could one day lay the foundation necessary to utilize this approach in humans after conducting clinical trials. The idea would be that a patient that needs a transplanted organ could first undergo a safe, gentle transplant with blood stem cells derived in the laboratory from embryonic stem cells. The same embryonic stem cells could also then be used to generate an organ that would be fully accepted by the recipient without requiring the need for long-term treatment with drugs to suppress the immune system. 

In a news release, Dr. Weissman is quoted as saying,

“With support by the California Institute for Regenerative Medicine, we’ve been able to make important advances in human embryonic stem cell research. In the past, these stem cell transplants have required a complete match to avoid rejection and reduce the chance of graft-versus-host disease. But in a family with four siblings the odds of having a sibling who matches the patient this closely are only one in four. Now we’ve shown in mice that a ‘half match,’ which occurs between parents and children or in two of every four siblings, works without the need for radiation, chemotherapy or ongoing immunosuppression. This may open up the possibility of transplant for nearly everyone who needs it. Additionally, the immune tolerance we’re able to induce should in the future allow the co-transplantation of [blood] stem cells and tissues, such as insulin-producing cells or even organs generated from the same embryonic stem cell line.”

The full results to this study were published in Cell Stem Cell.

Blood-brain barrier chip created with stem cells expands potential for personalized medicine

An Organ-Chip used in the study to create a blood-brain barrier (BBB).

The brain is a complex part of the human body that allows for the formation of thoughts and consciousness. In many ways it is the essence of who we are as individuals. Because of its importance, our bodies have developed various layers of protection around this vital organ, one of which is called the blood-brain barrier (BBB).

The BBB is a thin border of various cell types around the brain that regulate what can enter the brain tissue through the bloodstream. Its primary purpose is to prevent toxins and other unwanted substances from entering the brain and damaging it. Unfortunately this barrier can also prevent helpful medications, designed to fix problems, from reaching the brain.

Several brain disorders, such as Amyotrophic Lateral Sclerosis (ALS – also known as Lou Gehrig’s disease), Parkinson’s Disease (PD), and Huntington’s Disease (HD) have been linked to defective BBBs that keep out critical biomolecules needed for healthy brain activity.

In a CIRM-funded study, a team at Cedars-Sinai Medical Center created a BBB through the use of stem cells and an Organ-Chip made from induced pluripotent stem cells (iPSCs). These are a specific type of stem cells that can turn into any type of cell in the body and can be generated from a person’s own cells. In this study, iPSCs were created from adult blood samples and used to make the neurons and other supporting cells that make up the BBB. These cells were then placed inside an Organ-Chip which recreates the environment that cells normally experience within the human body.

Inside the 3-D Organ-Chip, the cells were able to form a BBB that functions as it does in the body, with the ability to block entry of certain drugs. Most notably, when the BBB was generated from cell samples of patients with HD, the BBB malfunctioned in the same way that it does in patients with the disease.

These findings expand the potential for personalized medicine for various brain disorders linked to problems in the BBB. In a press release, Dr. Clive Svendsen, director of the Cedars-Sinai Board of Governors Regenerative Medicine Institute and senior author of the study, was quoted as saying,

“The study’s findings open a promising pathway for precision medicine. The possibility of using a patient-specific, multicellular model of a blood barrier on a chip represents a new standard for developing predictive, personalized medicine.”

The full results of the study were published in the scientific journal Cell Stem Cell.