More than half a million people in the U.S. get dialysis multiple times a week. About 92,000 people are on the national transplant waiting list hoping for a kidney. Only about 20,000 people in the country receive a new kidney every year. The Kidney Project, founded in 1998, seeks to solve the problem for these patients. It’s a joint project between UC San Fransisco (UCSF) and Vanderbilt Univ. Medical Center.

An artificial kidney they are working on could someday end people’s reliance on dialysis or transplants.

The artificial kidney is called a bioreactor. It’s an implantable device that contains kidney cells. It works like a pacemaker — functioning continually with the body. Unlike a transplanted kidney from another person, the device wouldn’t cause an immune system response. When a person receives an organ from a donor, they have to take daily medications to prevent organ rejection. And, there simply aren’t enough donors for the number of people who need a kidney. Having an artificial option would be better.

The researchers implanted the kidney in pigs for seven days, and it worked well without being rejected. The artificial kidney doesn’t have every type of kidney cell in it. That limits the role it can play in health. The team is still working on adding more types of kidney cells to the bioreactor to perform all the vital functions of a normal kidney.

“The bioartificial kidney will make treatment for kidney disease more effective and also much more tolerable and comfortable,” said Dr. Shuvo Roy, the technical director of The Kidney Project.

Like an organic kidney, the bioreactor connects directly to the recipient’s blood vessels and veins to access nutrients and oxygen. But, silicon membranes keep the kidney cells away from the person’s immune system. That means the kidney cells can perform their jobs but can’t interact with the immune system.

“We needed to prove that a functional bioreactor will not require immunosuppressant drugs, and we did. We had no complications and can now iterate up, reaching for the whole panel of kidney functions at the human scale.” said Dr. Roy.

The next step in the research is to keep the device implanted in pigs for a month to ensure it still functions well. Then that has to be repeated in humans. The artificial kidney still needs more types of cells to fully replicate a fully functioning human kidney. But this is a massive step in the right direction.

Banner image: UC San Fransisco