The bioartificial kidney and bioengineered membranes in acute kidney injury

The treatment of severe acute kidney injury (AKI) with dialysis or hemofiltration remains suboptimal with high levels of morbidity and mortality. Current renal replacement therapies substitute for the small solute clearance function of the kidney but do not replace the lost reclamation, metabolic and endocrine functions of this organ. Cell therapy and tissue engineering offer hope of fuller replacement of kidney function in renal failure patients. A renal tubule assist device (RAD) that includes a conventional hemodialysis filter and a bioreactor containing living renal proximal tubule cells has been successfully engineered. Differentiated activity of these cells and survival advantages have been demonstrated in large-animal models of sepsis and AKI. Data from phase I/II and phase II clinical studies have shown that the addition of renal tubule cell therapy to conventional continuous renal replacement therapy (CRRT) treatment resulted in a significant clinical impact on survival, and that RAD treatment demonstrated an acceptable safety profile. Another substantive advance for the treatment of AKI will be the development of nanofabrication technology to further improve the clearance function of the kidney to replicate glomerular permselectivity while retaining high rates of hydraulic permeability. New developments in this translational research area will improve the unmet medical needs of patients with renal failure.