A system includes a dialyzer having a blood side and adialysate side, a first extracorporeal circuit including one or more firstfluid connectors for connecting the blood side of the dialyzer to thevascular system of a kidney patient, a second extracorporeal circuitincluding one or more second fluid connectors for connecting the dialysateside of the dialyzer to the vascular system of a healthy animal, a firstpump in fluid communication with at least one of the first and secondextracorporeal circuits, and a driver mechanically coupled to the firstpump, where the driver is configured to drive the first pump usingenergy from an energy source.
