UCSF team working on artificial kidney

UCSF team working on artificial kidney
November 16, 2010
By admin

Shuvo Roy had planned a career designing high-tech sensors and other devices for the aerospace industry. Instead, he’s building the world’s first artificial kidney.

The two fields aren’t as far apart as they might seem. So much of the engineering that Roy learned in school, he said, can be just as easily applied to the human body as it can to satellites and space shuttles. Bioengineering isn’t all that unlike electrical engineering.

“I was working with technology designed for harsh environments. And the human body is not exactly a friendly environment for foreign bodies,” said Roy with a grin, sitting in his sunny office at UCSF’s Mission Bay campus, where his lab is also located.

The artificial kidney is still at least five years away from being tested in a human patient. Researchers have built a large model of the kidney – so big that it filled a hospital room – and used it on human patients to show that the theories behind it will work. And parts of the small kidney have been successfully tested in animals.

If Roy’s team is successful, the kidney will be about the size of a large cup of coffee, and it would last for years, maybe decades, and require no pumps or batteries. Patients wouldn’t need anti-rejection drugs either, because there would be no exposed natural tissues for the immune system to attack.

“The payoff to the patient community is tremendous,” Roy said. “It could have a transformative impact on their lives.”
A long waiting list

The kidney would be a boon for the health care industry and the thousands of people who live with chronic kidney disease. More than 85,000 people in the United States are on the waiting list for a kidney transplant, and about 350,000 people with kidney failure rely on regular dialysis to remove the toxins from their blood.

But dialysis isn’t a cure, and it comes at a huge cost, both financially and in terms of its impact on patients’ quality of life. Medicare covers dialysis for anyone who needs it at a cost of about $75,000 a year per patient – that is 6 percent of the entire Medicare budget. Patients typically get the treatment three days a week, for three or more hours at a time.

An artificial kidney would potentially save the lives of people who need a kidney transplant and can’t find a donor, and it could spare thousands more from dialysis. Most patients don’t survive longer than five years on dialysis.

“Dialysis is a good thing. I’d be dead without it,” said David Anderson, 60, a San Francisco man who’s been on dialysis for a total of eight years, three of those after a failed kidney transplant. “But the notion that they could invent an artificial kidney that is encapsulated in the body, and you don’t have anti-rejection therapies, it’s just tremendous.”
Two-part instrument

The artificial kidney will be made of two parts – a filter side and a cellular side.

On the filter side, silicone membranes with microscopic pores will separate toxins from the blood, much as dialysis machines do. The body’s own blood pressure will force blood through the filter, so no pumps will be needed.

The key to the filtration side is the silicone membrane, which can be made fairly inexpensively and precisely, much as computer chips are. In a lot of ways, said UCSF bioengineer Tejal Desai, who has played a key role in designing the membrane filters, the work feels like something out of science fiction.

“But we’ve pushed it to where it’s not just a sci-fi concept, it’s something practical,” Desai said. “We’re thinking about this stuff in terms of a possibility to address a pressing health care need.”

On the cellular side, the filtered blood will be pumped over a bed of cells taken from either the patient’s own failing kidneys or from a donor. The cells will sense the chemical makeup of the filtered blood and trigger the body to maintain appropriate levels of salt, sugar and water.
More than just dialysis

Dialysis only filters the blood, so it doesn’t truly replace failing kidneys. The artificial kidney, on the other hand, is being designed to act in the same way as the actual organ.

“It mimics more of a kidney function than just dialysis,” said Roy, noting that the early tests of the artificial kidney – in the large model tested on humans – have shown a markedly improved survival rate when compared to treatment with just dialysis. “When we think of kidneys, we think of waste removal. And dialysis just does that. Dialysis doesn’t make you healthy – it just keeps you alive.”

The project is based out of UCSF, but there are about 40 scientists across the United States working on the artificial kidney. A group in Michigan is focused on the cellular side, and a group at UCSF is focused on the filtering system.

Now that both sides of the device have been tested in animals, the next step is to combine the two parts, and to build a model that is the right size and design for use in humans.

Once they’re ready to try the device in humans, Anderson said he’d gladly be the first to volunteer.

“I’d get it tomorrow if I could,” he said. “To me, this is a no-brainer.”
Renal care

350,000 People in the United States with kidney failure who rely on dialysis to remove the toxins from their blood.

85,000 People on a waiting list for a kidney transplant.

$75,000 Amount it costs Medicare per year per person to provide dialysis for anyone who needs it.

40 Number of scientists working on the artificial kidney.

E-mail Erin Allday at eallday@sfchronicle.com.

This article appeared on page A – 1 of the San Francisco Chronicle

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