April 30, 2008

Bioartificial Kidney Cuts Death Risk, Improves Outcomes

WEDNESDAY, April 30 (HealthDay News) -- Another successful clinical trial suggests that a bioartificial kidney to save the lives of people with acute renal failure will be available within a few years.

This latest study found that short-term replacement of renal cell function using the renal tubule assist device (RAD) -- the living cartridge that's critical to the function of the bioartificial kidney -- significantly reduced death risk and sped recovery of kidney function in patients with acute renal failure resulting from acute kidney injury.

The study of 58 critically ill patients, aged 18 to 80, found that the death rate after 28 days was 33 percent for patients who received continuous venovenous hemofiltration combined with RAD, compared to 66 percent for patients who received the more traditional continuous renal replacement therapy. At day 28, 53 percent of the patients in the RAD group had recovered renal function.

In the 180 days following treatment, patients in the RAD group had a 50 percent reduction in death risk. The study was published online in the Journal of the American Society of Nephrology.

"Our study results are encouraging, and they raise expectations that our new approach may yield a better treatment for life-threatening acute renal failure, for which a high mortality rate has remained unchanged [50 percent to 70 percent] despite years of advances in conventional therapies," study author Dr. H. David Humes, a professor of internal medicine at the University of Michigan School of Medicine, said in a prepared statement.

"Even more promising, the nature of our new approach -- using living cells as therapeutic agents -- argues for the feasibility of developing whole classes of new cell-based and tissue-engineered therapies," Humes said.

While this was a small study, he said it offers encouragement that a related device -- a wearable kidney that performs natural functions -- can be developed in the near future to treat people with chronic renal failure.

"The ability to harness vital processes of cells, to target their living molecular machinery on restoring critical substances which have become disordered by disease, has vast implications for the future of medicine," Humes said. "The apparently successful use of living cells in this way validates our approach and should encourage others to investigate cell therapies for a range of disorders."

He and his colleagues started developing the bioartificial kidney more than a decade ago. The device includes a cartridge that filters the blood as in traditional kidney dialysis. The cartridge is connected to the RAD, which is made of hollow fibers lined with a type of kidney cell called renal proximal tubule cells, which reclaim vital electrolytes, salt, glucose and water, and control production of immune system molecules called cytokines, which fight infection.

More information

The American Academy of Family Physicians has more about kidney failure.

-- Robert Preidt
SOURCE: University of Michigan Health System, news release, April 24, 2008
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