Developments to Watch
IN THE WORKS: MAN-MADE KIDNEYS
THE HUMAN KIDNEY EXCELS AT FILTERING TOXINS FROM the blood while reabsorbing vital nutrients to maintain the body's chemical balance. Mechanical dialysis, which lacks the reabsorption mechanism, is a poor surrogate. Even so, some 400,000 Americans with kidney problems resort to dialysis each year--at a cost of about $12 billion.
Toward the end of this decade, predicts David Humes, professor of internal medicine at the University of Michigan, advances in so-called tissue engineering will lead to implantable artificial kidneys that begin to emulate the natural organ. Working with Nephros Therapeutics, a University of Michigan spin-off created to commercialize his ideas, Humes has designed a device with two different chambers to handle filtration and reabsorption. Each chamber is filled with porous, hollow fibers lined with cultured kidney cells (illustration) and cells from blood vessels that prevent coagulation. Insulated from the host patient's immune system by plastic casing, the living cells won't be subject to rejection.
To speed the inventions to patients who need them, Nephros will develop the two components separately. The first product--a reabsorption unit designed as an external aid to conventional dialysis--should be ready for human clinical trials in about two years.EDITED BY NEIL GROSS