The bioartificial kidney in the treatment of acute renal failure

The application of cell therapy to the successful substitution process of hemofiltration may improve the poor prognosis of patients with acute renal failure (ARF) in the intensive care unit. An extracorporeal bioartificial kidney consisting of a conventional hemofilter followed in series with a renal tubule assist device (RAD) has been developed. The RAD is a hemofiltration cartridge containing 109 human renal tubule cells grown as monolayers along the inner surface of the hollow fibers. The fibers provide a porous scaffold that is immunoprotective. The ultrafiltrate from the hemofilter is delivered to the luminal compartment of the RAD, and the postfiltered blood is delivered to the extracapillary space of the RAD. The RAD has been shown to possess multiple differentiated transport, metabolic, and endocrinologic activities of renal epithelium. These activities have been demonstrated to occur when the RAD is placed in the extracorporeal circuit of the bioartificial kidney in uremic animals. This approach may improve the current therapies used to treat patients with ARF because of the RAD's ability to restore lost metabolic renal function and cytokine balance in these desperately ill patients. In this regard, the RAD was able to ameliorate endotoxin and bacteremic shock in uremic animals by altering cytokine levels, improve mean arterial blood pressure, and maintain better cardiac output. With these supportive preclinical data, an FDA-approved phase I/II clinical trial has been initiated and early results are encouraging.