Half a million people in the U.S. get dialysis several times per week because of kidney failure. UCSF researchers at The Kidney Project made a breakthrough with an implantable artificial kidney, proving that the bioreactor can safely house kidney cells in large animals for a week without triggering an immune reaction. The cells, which balance electrolytes in the blood and produce Vitamin D, remained healthy in the bioreactor for one week. "The bioartificial kidney will make treatment for kidney disease more effective and also much more tolerable and comfortable," says Shuvo Roy, PhD, UCSF Bioengineering Professor and head of The Kidney Project.