Scientists make progress with growing organs for transplants

Scientists make progress with growing organs for transplants

Researchers from the University of Cambridge have laid the foundations for growing synthetic embryos that could develop a beating heart, gut and brain.

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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.

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Peter Rogers
Dr. Peter Rogers grew up milking cows and building barns. This provided him the transferable skills necessary for a smooth transition into academic research. Three years of genetics research led to six years of immunology research, which led to a Ph.D. from Auburn University. That led to three and half years of instructional design research at Tufts University School of Medicine. His expertise includes biomedical sciences & technology, social determinants of health, bovine birthing, training & development, and cognitive psychology. He’s taught dozens of university courses, ranging from Principles of Biology to Advanced Medical Immunology. He is currently co-writing a book with his father, George Rogers, called "How to Correctly Hold a Flashlight: A Disagreement in Academic and Agricultural Perspectives."
Researchers advance drugs that treat pain without addiction

New therapies are using creative approaches that target the body’s sensory neurons, which send pain signals to the brain.

Neurocarrus

Opioids are one of the most common ways to treat pain. They can be effective but are also highly addictive, an issue that has fueled the ongoing opioid crisis. In 2020, an estimated 2.3 million Americans were dependent on prescription opioids.

Opioids bind to receptors at the end of nerve cells in the brain and body to prevent pain signals. In the process, they trigger endorphins, so the brain constantly craves more. There is a huge risk of addiction in patients using opioids for chronic long-term pain. Even patients using the drugs for acute short-term pain can become dependent on them.

Scientists have been looking for non-addictive drugs to target pain for over 30 years, but their attempts have been largely ineffective. “We desperately need alternatives for pain management,” says Stephen E. Nadeau, a professor of neurology at the University of Florida.

A “dimmer switch” for pain

Paul Blum is a professor of biological sciences at the University of Nebraska. He and his team at Neurocarrus have created a drug called N-001 for acute short-term pain. N-001 is made up of specially engineered bacterial proteins that target the body’s sensory neurons, which send pain signals to the brain. The proteins in N-001 turn down pain signals, but they’re too large to cross the blood-brain barrier, so they don’t trigger the release of endorphins. There is no chance of addiction.

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Sarah Philip
Sarah Philip is a London-based freelance journalist who writes about science, film and TV. You can follow her on Twitter @sarahph1lip.
Our devices are changing us

Tech-related injuries are becoming more common as many people depend on - and often develop addictions for - smart phones and computers.

In the 1990s, a mysterious virus spread throughout the Massachusetts Institute of Technology Artificial Intelligence Lab—or that’s what the scientists who worked there thought. More of them rubbed their aching forearms and massaged their cricked necks as new computers were introduced to the AI Lab on a floor-by-floor basis. They realized their musculoskeletal issues coincided with the arrival of these new computers—some of which were mounted high up on lab benches in awkward positions—and the hours spent typing on them.

Today, these injuries have become more common in a society awash with smart devices, sleek computers, and other gadgets. And we don’t just get hurt from typing on desktop computers; we’re massaging our sore wrists from hours of texting and Facetiming on phones, especially as they get bigger in size.

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Hanna Webster
Hanna Webster is a freelance science writer based in San Diego, California. She received a Bachelor’s degree in neuroscience and creative writing in 2018 from Western Washington University, and is now a graduate student in the MA Science Writing program at Johns Hopkins University. She writes stories about neuroscience, biology, and public health. Her essays and articles have appeared in Jeopardy Magazine and Leafly. When Hanna is not writing, she enjoys consuming other art forms, such as photography, poetry, creative nonfiction, and live music