UF working to grow transplant kidneys from stem cells
Published: Friday, January 24, 2014 at 10:00 p.m.
Last Modified: Friday, January 24, 2014 at 6:16 p.m.
In the ground-floor labyrinth that connects UF Health Shands Hospital to the UF health sciences campus, a handful of scientists are super excited about research that one day could mean the end of long waiting lines for kidney transplant patients.
The promise lies in a soft sponge-like structure that is about the size of a bar of soap and is considered a "scaffold" for building healthy human kidneys.
The soap-sized structure is a baby pig's kidney, drained of its blood and cells. Over the course of three days, chemicals strip the kidney of swine cells so it can be injected with human stem cells.
The idea of using stem cells to grow new organs is not new. Scientists have been plugging away at it for two decades, said Dr. Edward Ross, a nephrologist and professor of medicine at UF Health.
"The dream of taking patients' stem cells and growing an organ never came to fruition," Ross said. "Short of growing the organ de novo is (the idea) to somehow nudge the cells along to some sort of biological scaffold from a creature."
Pigs' kidneys are similar to those of humans in size and basic anatomy, so scientists have been studying the concept of using the pig's kidney as a scaffold. They also have experimented with rabbits and rats.
Scientists also have successfully grown human stem cells with other, "easier" organs such as the bladder and trachea, Ross said.
"(The kidney) is one of the most difficult because of the complexity of the organ," he said.
The scaffold is not, however, just an inert skeleton. It contains proteins with chemical signals that guide human stem cells once they are implanted, or "seeded," inside the scaffold. The kidney contains 30 different cell types, so the stem cells can differentiate into these types once inside the scaffold.
The scaffold also is continuously pumped with nutrients such as oxygen, sugars and proteins to help the stem cells develop into a newly formed kidney.
The scaffold gradually begins to redden as it morphs into an adult kidney, Ross said.
"It's still very new and very exciting," he said.
UF is one of about a half-dozen places in the world where this type of research is going on, Ross added. It might take another decade before the science is ready for the clinic.
Funding is the main hurdle, namely cuts at the National Institutes of Health, which has funded much of stem cell research so far, he said.
But the wait will be worth it, especially for the approximately 106,000 kidney transplant patients on the waiting list in the U.S. alone, said Christopher Batich, the pilot program director of the UF Clinical and Translational Science Institute and a professor of materials science and engineering.
At any one time, Shands has about 100-120 chronic kidney disease patients awaiting a transplant, Batich added.
One of the main advantages to having patients grow their own kidneys is eliminating the need for anti-rejection drugs they take when they receive a donor kidney, Batich said, adding that the drugs are known to cause side effects such as cancer.
The research is Batich's own brainchild and dates back to the 1980s, when he met a pharmacologist at a scientific conference who was studying decellularized kidneys.
Several years went by before Batich was able to find another researcher with the time and interest in working on the scaffolds.
Now, several types of researchers are involved: nephrologists, material scientists, biomedical engineers, pathologists and developmental biologists.
"I think there's a huge need, and a huge opportunity," Batich said of the research. "It's going to take money, time, experience and some luck."
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