We first proposed a method of using dialysis virtually continuously in the late 1970’s. Our approach was to employ a small dialyzer and a bioreactor to keep the dialysate “clean”. It was based upon our development of strains of microbes that degraded urea and creatinine (among other nitrogenous compounds) rapidly (US Patent 4218541). As biochemical engineering evolved, we began examining the use of stem cells. We understood the technology could replace dialysis within a decade or so; we did not understand that politics would preclude that development for some 30 years or more.)
Now, Dr. Shuvo Roy, leading an interdisciplinary effort at UC San Francisco, has completed the first stage of development of a bio-artificial kidney that he first worked on at the Cleveland Clinic and the University of Michigan. (This development was funded by NIH- the National Institute of Biomedical Imaging and Bioengineering- with a $ 3.2 million grant that just expired.) Dr. Roy is affiliated with the Department of Bioengineering and Therapeutic Sciences (joint effort of the schools of Medicine and Pharmacy). The other nine members of the team are from his former affiliations, as well as Penn State, Ohio State, and Case Western Reserve Universities.
The bioartificial kidney is a two state device; a membrane nano-filtration system (micro-perforated sheets of silicon) to remove toxins and a bioreactor (containing bioengineered kidney cells, that are able to effect the functions as a healthy kidney, including regulating blood pressure and producing Vitamin D). The goal is to further improve and develop the device so there is no external power supply, and having the patient’s blood pressure providing the forces needed to filter out the toxins. While this device is a tremendous reduction in size from the first concept (about the size of a room), it is hoped to reduce the size to some 250 cm3 (250 ml).
This device is to be a replacement for transplants as well as dialysis. Right now, there are only some 17000 transplants a year (demand is roughly 5 times that number), due to a dearth of donors and compatibility issues. (It is presumed that receivers of this device will not require anti-immunity treatments, which are required for transplant patients.) The bulk of the other ESRD patients are treated with dialysis (which only provides for the equivalent of about 15% of true kidney function). The five-year survivability on dialysis is about 35%, primarily due to the see-saw affect described earlier, the missing 85% functionality, and other factors [to be discussed later].
The group is anticipating receiving both public and private funds to continue development. It is hoped that animal and human testing will be completed by the end of the decade. (Perhaps by then a true stem-cell derived kidney may also be available.).