Researchers from the University of Cambridge have laid the foundations for growing synthetic embryos that could develop a beating heart, gut and brain.
Story by Big Think
For over a century, scientists have dreamed of growing human organs sans humans. This technology could put an end to the scarcity of organs for transplants. But that’s just the tip of the iceberg. The capability to grow fully functional organs would revolutionize research. For example, scientists could observe mysterious biological processes, such as how human cells and organs develop a disease and respond (or fail to respond) to medication without involving human subjects.
Recently, a team of researchers from the University of Cambridge has laid the foundations not just for growing functional organs but functional synthetic embryos capable of developing a beating heart, gut, and brain. Their report was published in Nature.
The organoid revolution
In 1981, scientists discovered how to keep stem cells alive. This was a significant breakthrough, as stem cells have notoriously rigorous demands. Nevertheless, stem cells remained a relatively niche research area, mainly because scientists didn’t know how to convince the cells to turn into other cells.
Then, in 1987, scientists embedded isolated stem cells in a gelatinous protein mixture called Matrigel, which simulated the three-dimensional environment of animal tissue. The cells thrived, but they also did something remarkable: they created breast tissue capable of producing milk proteins. This was the first organoid — a clump of cells that behave and function like a real organ. The organoid revolution had begun, and it all started with a boob in Jello.
For the next 20 years, it was rare to find a scientist who identified as an “organoid researcher,” but there were many “stem cell researchers” who wanted to figure out how to turn stem cells into other cells. Eventually, they discovered the signals (called growth factors) that stem cells require to differentiate into other types of cells.
For a human embryo (and its organs) to develop successfully, there needs to be a “dialogue” between these three types of stem cells.
By the end of the 2000s, researchers began combining stem cells, Matrigel, and the newly characterized growth factors to create dozens of organoids, from liver organoids capable of producing the bile salts necessary for digesting fat to brain organoids with components that resemble eyes, the spinal cord, and arguably, the beginnings of sentience.
Synthetic embryos
Organoids possess an intrinsic flaw: they are organ-like. They share some characteristics with real organs, making them powerful tools for research. However, no one has found a way to create an organoid with all the characteristics and functions of a real organ. But Magdalena Żernicka-Goetz, a developmental biologist, might have set the foundation for that discovery.
Żernicka-Goetz hypothesized that organoids fail to develop into fully functional organs because organs develop as a collective. Organoid research often uses embryonic stem cells, which are the cells from which the developing organism is created. However, there are two other types of stem cells in an early embryo: stem cells that become the placenta and those that become the yolk sac (where the embryo grows and gets its nutrients in early development). For a human embryo (and its organs) to develop successfully, there needs to be a “dialogue” between these three types of stem cells. In other words, Żernicka-Goetz suspected the best way to grow a functional organoid was to produce a synthetic embryoid.
As described in the aforementioned Nature paper, Żernicka-Goetz and her team mimicked the embryonic environment by mixing these three types of stem cells from mice. Amazingly, the stem cells self-organized into structures and progressed through the successive developmental stages until they had beating hearts and the foundations of the brain.
“Our mouse embryo model not only develops a brain, but also a beating heart [and] all the components that go on to make up the body,” said Żernicka-Goetz. “It’s just unbelievable that we’ve got this far. This has been the dream of our community for years and major focus of our work for a decade and finally we’ve done it.”
If the methods developed by Żernicka-Goetz’s team are successful with human stem cells, scientists someday could use them to guide the development of synthetic organs for patients awaiting transplants. It also opens the door to studying how embryos develop during pregnancy.
This article originally appeared on Big Think, home of the brightest minds and biggest ideas of all time.
On today’s podcast episode, Leaps.org spoke with Shai Efrati, a physician and professor in the schools of medicine and neuroscience at Tel Aviv University, about the potential health benefits of hyperbaric oxygen therapy.
We talk about what’s going in on the body during hyperbaric oxygen therapy that could possibly lead to transformative benefits for patients, some of whom had searched for treatments previously and come up empty. We also discuss exactly where Efrati is with this line of inquiry, both what his studies have shown and the great deal of additional research that’s needed before the healthcare system can and should fully embrace hyperbaric oxygen therapy.
Efrati and I talk about why you can’t just go on Amazon and buy something that says hyperbaric – the only way it can have a positive effect is if you access the real version of the chamber and use it correctly under the supervision of a knowledgeable physician.
I also ask Efrati what we know about the short- and long-term risks for those who follow the research-based protocol on a regular basis. And what about accessibility to people without a lot of extra cash to spend on their health? Efrati is already rolling out this therapy at a small number of specialized clinics in places like the Villages retirement community in Florida.
Shai Efrati
Hiking is one of Marci Flory's favorite activities, but her chronic Lyme disease sometimes renders her unable to walk. Biotech companies Pfizer and Valneva are testing a vaccine for Lyme disease in a Phase III clinical trial.
“Initially doctors thought I had ALS, or less likely, multiple sclerosis,” she says. “But after repeated MRI scans for a year, they concluded I had a rare neurological condition called acute transverse myelitis.”
But Flory was not convinced. After ordering a variety of private blood tests, she discovered she was infected with a range of bacteria in the genus Borrelia that live in the guts of ticks, the infectious agents responsible for Lyme disease.
“It made sense,” she says. “Looking back, I was bitten in high school and misdiagnosed with mononucleosis. This was probably the start, and my immune system kept it under wraps for a while. The Lyme bacteria can burrow into every tissue in the body, go into cyst form and become dormant before reactivating.”
The reason why cases of Lyme disease are increasing is down to changing weather patterns, triggered by climate change, meaning that ticks are now found across a much wider geographic range than ever before.
When these species of bacteria are transmitted to humans, they can attack the nervous system, joints and even internal organs which can lead to serious health complications such as arthritis, meningitis and even heart failure. While Lyme disease can sometimes be successfully treated with antibiotics if spotted early on, not everyone responds to these drugs, and for patients who have developed chronic symptoms, there is no known cure. Flory says she knows of fellow Lyme disease patients who have spent hundreds of thousands of dollars seeking treatments.
Concerningly, statistics show that Lyme and other tick-borne diseases are on the rise. Recently released estimates based on health insurance records suggest that at least 476,000 Americans are diagnosed with Lyme disease every year, and many experts believe the true figure is far higher.
The reason why the numbers are growing is down to changing weather patterns, triggered by climate change, meaning that ticks are now found across a much wider geographic range than ever before. Health insurance data shows that cases of Lyme disease have increased fourfold in rural parts of the U.S. over the last 15 years, and 65 percent in urban regions.
As a result, many scientists who have studied Lyme disease feel that it is paramount to bring some form of protective vaccine to market which can be offered to people living in the most at-risk areas.
“Even the increased awareness for Lyme disease has not stopped the cases,” says Eva Sapi, professor of cellular and molecular biology at the University of New Haven. “Some of these patients are looking for answers for years, running from one doctor to another, so that is obviously a very big cost for our society at so many levels.”
Emerging vaccines – and backlash
But with the rising case numbers, interest has grown among the pharmaceutical industry and research communities. Vienna-based biotech Valneva have partnered with Pfizer to take their vaccine – a seasonal jab which offers protection against the six most common strains of Lyme disease in the northern hemisphere – into a Phase III clinical trial which began in August. Involving 6,000 participants in a number of U.S. states and northern Europe where Lyme disease is endemic, it could lead to a licensed vaccine by 2025, if it proves successful.
“For many years Lyme was considered a small market vaccine,” explains Monica E. Embers, assistant professor of parasitology at Tulane University in New Orleans. “Now we know that this is a much bigger problem, Pfizer has stepped up to invest in preventing this disease and other pharmaceutical companies may as well.”
Despite innovations, patient communities and their representatives remain ambivalent about the idea of a vaccine. Some of this skepticism dates back to the failed LYMErix vaccine which was developed in the late 1990s before being withdrawn from the market.
At the same time, scientists at Yale University are developing a messenger RNA vaccine which aims to train the immune system to respond to tick bites by exposing it to 19 proteins found in tick saliva. Whereas the Valneva vaccine targets the bacteria within ticks, the Yale vaccine attempts to provoke an instant and aggressive immune response at the site of the bite. This causes the tick to fall off and limits the potential for transmitting dangerous infections.
But despite these innovations, patient communities and their representatives remain ambivalent about the idea of a vaccine. Some of this skepticism dates back to the failed LYMErix vaccine which was developed in the late 1990s before being withdrawn from the market in 2002 after concerns were raised that it might induce autoimmune reactions in humans.
While this theory was ultimately disproved, the lingering stigma attached to LYMErix meant that most vaccine manufacturers chose to stay away from the disease for many years, something which Gregory Poland, head of the Mayo Clinic’s Vaccine Research Group in Minnesota, describes as a tragedy.
“Since 2002, we have not had a human Lyme vaccine in the U.S. despite the increasing number of cases,” says Poland. “Pretty much everyone in the field thinks they’re ten times higher than the official numbers, so you’re probably talking at least 400,000 each year. It’s an incredible burden but because of concerns about anti-vax protestors, until very recently, no manufacturer has wanted to touch this.”
Such was the backlash surrounding the failed LYMErix program that scientists have even explored the most creative of workarounds for protecting people in tick-populated regions, without needing to actually vaccinate them. One research program at the University of Tennessee came up with the idea of leaving food pellets containing a vaccine in woodland areas with the idea that rodents would eat the pellets, and the vaccine would then kill Borrelia bacteria within any ticks which subsequently fed on the animals.
Even the Pfizer-Valneva vaccine has been cautiously designed to try and allay any lingering concerns, two decades after LYMErix. “The concept is the same as the original LYMErix vaccine, but it has been made safer by removing regions that had the potential to induce autoimmunity,” says Embers. “There will always be individuals who oppose vaccines, Lyme or otherwise, but it will be a tremendous boost to public health to have the option.”
Vaccine alternatives
Researchers are also considering alternative immunization approaches in case sufficiently large numbers of people choose to reject any Lyme vaccine which gets approved. Researchers at UMass Chan Medical School have developed an artificially generated antibody, administered via an annual injection, which is capable of killing Borrelia bacteria in the guts of ticks before they can get into the human host.
So far animal studies have shown it to be 100 percent effective, while the scientists have completed a Phase I trial in which they tested it for safety on 48 volunteers in Nebraska. Because this approach provides the antibody directly, rather than triggering the human immune system to produce the antibody like a vaccine would, Embers predicts that it could be a viable alternative for the vaccine hesitant as well as providing an option for immunocompromised individuals who cannot produce enough of their own antibodies.
At the same time, many patient groups still raise concerns over the fact that numerous diagnostic tests for Lyme disease have been reported to have a poor accuracy. Without this, they argue that it is difficult to prove whether vaccines or any other form of immunization actually work. “If the disease is not understood enough to create a more accurate test and a universally accepted treatment protocol, particularly for those who weren’t treated promptly, how can we be sure about the efficacy of a vaccine?” says Natasha Metcalf, co-founder of the organization Lyme Disease UK.
Flory points out that there are so many different types of Borrelia bacteria which cause Lyme disease, that the immunizations being developed may only stop a proportion of cases. In addition, she says that chronic Lyme patients often report a whole myriad of co-infections which remain poorly understood and are likely to also be involved in the disease process.
Marci Flory undergoes an infusion in an attempt to treat her Lyme disease symptoms.
Marci Flory
“I would love to see an effective Lyme vaccine but I have my reservations,” she says. “I am infected with four types of Borrelia bacteria, plus many co-infections – Babesia, Bartonella, Erlichiosis, Rickettsia, and Mycoplasma – all from a single Douglas County Kansas tick bite. Lyme never travels alone and the vaccine won’t protect against all the many strains of Borrelia and co-infections.”
Valneva CEO Thomas Lingelbach admits that the Pfizer-Valneva vaccine is not perfect, but predicts that it will still have significant impact if approved.
“We expect the vaccine to have 75 percent plus efficacy,” he says. “There is this legacy around the old Lyme vaccines, but the world is very, very different today. The number of clinical manifestations known to be caused by infection with Lyme Borreliosis has significantly increased, and the understanding around severity has certainly increased.”
Embers agrees that while it will still be important for doctors to monitor for other tick-borne infections which are not necessarily covered by the vaccine, having any clinically approved jab would still represent a major step forward in the fight against the disease.
“I think that any vaccine must be properly vetted, and these companies are performing extensive clinical trials to do just that,” she says. “Lyme is the most common tick-borne disease in the U.S. so the public health impact could be significant. However, clinicians and the general public must remain aware of all of the other tick-borne diseases such as Babesia and Anaplasma, and continue to screen for those when a tick bite is suspected.”