Lab-Grown Mini Kidneys Are Bringing Science Closer to Custom Organs

A model of a human kidney.

(Photo by Robina Weermeijer on Unsplash)


Science's dream of creating perfect custom organs on demand as soon as a patient needs one is still a long way off. But tiny versions are already serving as useful research tools and stepping stones toward full-fledged replacements.

Although organoids cannot yet replace kidneys, they are invaluable tools for research.

The Lowdown

Australian researchers have grown hundreds of mini human kidneys in the past few years. Known as organoids, they function much like their full-grown counterparts, minus a few features due to a lack of blood supply.

Cultivated in a petri dish, these kidneys are still a shadow of their human counterparts. They grow no larger than one-sixth of an inch in diameter; fully developed organs are up to five inches in length. They contain no more than a few dozen nephrons, the kidney's individual blood-filtering unit, whereas a fully-grown kidney has about 1 million nephrons. And the dish variety live for just a few weeks.

An organoid kidney created by the Murdoch Children's Institute in Melbourne, Australia.

Photo Credit: Shahnaz Khan.

But Melissa Little, head of the kidney research laboratory at the Murdoch Children's Institute in Melbourne, says these organoids are invaluable tools for research. Although renal failure is rare in children, more than half of those who suffer from such a disorder inherited it.

The mini kidneys enable scientists to better understand the progression of such disorders because they can be grown with a patient's specific genetic condition.

Mature stem cells can be extracted from a patient's blood sample and then reprogrammed to become like embryonic cells, able to turn into any type of cell in the body. It's akin to walking back the clock so that the cells regain unlimited potential for development. (The Japanese scientist who pioneered this technique was awarded the Nobel Prize in 2012.) These "induced pluripotent stem cells" can then be chemically coaxed to grow into mini kidneys that have the patient's genetic disorder.

"The (genetic) defects are quite clear in the organoids, and they can be monitored in the dish," Little says. To date, her research team has created organoids from 20 different stem cell lines.

Medication regimens can also be tested on the organoids, allowing specific tailoring for each patient. For now, such testing remains restricted to mice, but Little says it eventually will be done on human organoids so that the results can more accurately reflect how a given patient will respond to particular drugs.

Next Steps

Although these organoids cannot yet replace kidneys, Little says they may plug a huge gap in renal care by assisting in developing new treatments for chronic conditions. Currently, most patients with a serious kidney disorder see their options narrow to dialysis or organ transplantation. The former not only requires multiple sessions a week, but takes a huge toll on patient health.

Ten percent of older patients on dialysis die every year in the U.S. Aside from the physical trauma of organ transplantation, finding a suitable donor outside of a family member can be difficult.

"This is just another great example of the potential of pluripotent stem cells."

Meanwhile, the ongoing creation of organoids is supplying Little and her colleagues with enough information to create larger and more functional organs in the future. According to Little, researchers in the Netherlands, for example, have found that implanting organoids in mice leads to the creation of vascular growth, a potential pathway toward creating bigger and better kidneys.

And while Little acknowledges that creating a fully-formed custom organ is the ultimate goal, the mini organs are an important bridge step.

"This is just another great example of the potential of pluripotent stem cells, and I am just passionate to see it do some good."

Ron Shinkman
Ron Shinkman is a veteran journalist whose work has appeared in the New England Journal of Medicine publication Catalyst, California Health Report, Fierce Healthcare, and many other publications. He has been a finalist for the prestigious NIHCM Foundation print journalism award twice in the past five years. Shinkman also served as Los Angeles Bureau Chief for Modern Healthcare and as a staff reporter for the Los Angeles Business Journal. He has an M.A. in English from California State University and a B.A. in English from UCLA.
Get our top stories twice a month
Follow us on

Recent immigration restrictions have left many foreign researchers' projects and careers in limbo—and some in jeopardy.

Unsplash

This article is part of the magazine, "The Future of Science In America: The Election Issue," co-published by LeapsMag, the Aspen Institute Science & Society Program, and GOOD.

When COVID-19 cases were surging in New York City in early spring, Chitra Mohan, a postdoctoral fellow at Weill Cornell, was overwhelmed with worry. But the pandemic was only part of her anxieties. Having come to the United States from India on a student visa that allowed her to work for a year after completing her degree, she had applied for a two-year extension, typically granted for those in STEM fields. But due to a clerical error—Mohan used an electronic signatureinstead of a handwritten one— her application was denied and she could no longerwork in the United States.

"I was put on unpaid leave and I lost my apartment and my health insurance—and that was in the middle of COVID!" she says.

Meanwhile her skills were very much needed in those unprecedented times. A molecular biologist studying how DNA can repair itself, Mohan was trained in reverse transcription polymerase chain reaction or RT-PCR—a lab technique that detects pathogens and is used to diagnose COVID-19. Mohan wanted to volunteer at testing centers, but because she couldn't legally work in the U.S., she wasn't allowed to help either. She moved to her cousin's house, hired a lawyer, and tried to restore her work status.

Keep Reading Keep Reading
Lina Zeldovich
Lina Zeldovich has written about science, medicine and technology for Scientific American, Reader’s Digest, Mosaic Science and other publications. She’s an alumna of Columbia University School of Journalism and the author of the upcoming book, The Other Dark Matter: The Science and Business of Turning Waste into Wealth, from Chicago University Press. You can find her on http://linazeldovich.com/ and @linazeldovich.

The White House in Washington, D.C.

Unsplash

This article is part of the magazine, "The Future of Science In America: The Election Issue," co-published by LeapsMag, the Aspen Institute Science & Society Program, and GOOD.

We invited Nobel Prize, National Medal of Science, and Breakthrough Prize Laureates working in America to offer advice to the next President on how to prioritize science and medicine in the next four years. Almost universally, these 28 letters underscore the importance of government support for basic or fundamental research to fuel long-term solutions to challenges like infectious diseases, climate change, and environmental preservation.

Many of these scientists are immigrants to the United States and emphasize how they moved to this country for its educational and scientific opportunities, which recently have been threatened by changes in visa policies for students and researchers from overseas. Many respondents emphasize the importance of training opportunities for scientists from diverse backgrounds to ensure that America can continue to have one of the strongest, most creative scientific workforces in the world.

Keep Reading Keep Reading
Aaron F. Mertz
Aaron F. Mertz, Ph.D., is a biophysicist, science advocate, and the founding Director of the Aspen Institute Science & Society Program, launched in 2019 to help foster a diverse scientific workforce whose contributions extend beyond the laboratory and to generate greater public appreciation for science as a vital tool to address global challenges. He completed postdoctoral training in cell biology at Rockefeller University, a doctorate in physics at Yale University, a master’s degree in the history of science at the University of Oxford as a Rhodes Scholar, and a bachelor’s degree in physics at Washington University in St. Louis.