Renal Replacement Devices: The Development of the Bioartificial Kidney

Abstract

With the creation of artificial organ technology, the concept of replacement of failed natural organs has shifted focus from mere life-saving objectives to a broader goal to fulfill quality of life expectations. The kidney was the first solid organ whose function was approximated by a man-made synthetic device and also the first organ replaced by autologous transplantation on a long-term basis. Current organ substitution techniques for end stage renal disease (ESRD) involve either transplanting human kidneys or attempting substitution for functions of diseased kidneys through dialysis. Despite encouraging and improving results from organ transplantation, the preferred choice of substitution therapy, it is still hampered by a shortage of organs, chronic transplant loss, and a changed patient population (Hillebrand and Land 1996). Dialysis therapy only partially replaces the filtration component of renal function and is still an imperfect, intermittent, expensive, and time-consuming replacement of renal function. Dialysis also indiscriminately removes solutes, fails to substitute for renal hormonal and metabolic activities, and requires dietary restrictions and drug therapy to maintain the patient in a state of suboptimal health. The kidney is not simply a filter that produces urine as a waste product, but by monitoring and adjusting the concentrations of multiple compounds in the blood within very narrow limits, it regulates the internal environment to maintain near-perfect homeostasis. The realization that the complexity and amazing efficiency of the natural kidneys cannot be easily mimicked by man-made materials motivates work towards providing a biological component to the artificial kidney device. Hybridization, which means the combining of biological tissues with artificial hardware, is the most plausible solution to constructing “near-natural” kidneys. When such a neoartificial kidney is implanted, it will allow a continuous, increased level of filtration and will also replace the metabolic and endocrine functions “naturally.” This approach may circumvent the shortage problem posed by renal transplantations.