Present status and perspective of the development of a bioartificial kidney for chronic renal failure patients.

A bioartificial tubule device was applied for the treatment of 10 acute renal failure and multiple organ failure patients by Humes et al. A bioartificial kidney for chronic renal failure patients, however, has never been applied. In order to develop a bioartificial kidney for preventing and treating long-term complications of maintenance dialysis patients, we have to overcome difficulties such as antithrombogenic issue of hemofilters and development of long functioning tubule devices in the context of economical and easy treatment. Continuous hemofilters should modify with an antithrombogenic material on the inner surfaces of membranes to get more hemocompatible characteristics. We are developing an antithrombogenic continuous hemofilter coating with methacryloyloxyethyl phosphorylcholine polymer which will mimic phospholipid layers of human cell membrane on the inner surface of a hemofilter. The transportability of H2O, Na+, and glucose of bioartificial tubule devices using polysulfone hollow fiber modules and porcine proximal tubular epithelial cells LLC-PK1 were evaluated using two kinds of circuits of different medium inside and outside of the cell-attached hollow fiber membrane. Transport of H2O, Na+, and glucose were significantly increased when 2.5 g/dL of albumin was added, and plateaued on the eight day and then decreased thereafter until the 13th day. Transfection of a specific gene into human tubular epithelial cells might be required to keep contact inhibition in order to maintain a confluent monolayer for longer duration.