Development of bio-artificial kidney

阴离子型中分子尿毒症毒素是慢性肾功能衰竭患者动脉硬化的主要原因，常规血液透析不能清除。大多数毒素，如硫酸吲哚酚，通过有机阴离子转运蛋白-3（OAT-3）在健康受试者的近端小管细胞中分泌。为了开发一种新的杂交人工肾，其中过表达OAT-3的近端小管细胞在中空纤维上培养，我们进行了以下实验：1）我们建立了培养的过表达OAT-3的近端小管细胞。我们通过Western blot和免疫组化证实了硫酸吲哚酚在细胞中的更高转运以及更高的蛋白表达。2）我们成功地将细胞接种到我们先前证实的中空纤维模块上。3）我们发现该系统在体外对硫酸吲哚酚有更高的选择性去除。硫酸吲哚酚的清除率为38 ml/min/m2，比对照细胞高8倍。4）我们还将该系统应用于有或无肾衰竭的狗。我们发现硫酸吲哚酚从肾衰竭犬循环血液中的清除能力高，且不良反应少。因此，我们成功地开发了一种新型的近端肾小管细胞过表达OAT-3的杂交人工肾。该系统可用于去除常规血液透析无法去除的尿毒症毒素。

Anionic middle molecule uremic toxins, which can not be removed by conventional hemodialysis, play major role for progress of arteriosclerosis in patients with chronic renal failure. Most of the toxins, such as indoxyl sulfate, is secreted via organic anion transporter-3 (OAT-3) in proximal tubule cells in healthy subjects. To develop a novel hybrid artificial kidney, where the proximal tubular cells over-expressing OAT-3 are cultured on hollow fibers, we performed following experiments.1) We established cultured proximal tubule cells over-expressing OAT-3. We confirmed higher transport of indoxyl sulfate in the cells and also higher expression of the protein by Western blot and immuno-histochemistry.2) We succeeded to seed the cells onto hollowfiber modules, which we previously reported.3) We found higher selective removal of indoxyl sulfate by the system in vitro. The clearance of indoxyl sulfate was 38 ml/min/m2, which was 8-times higher than that with control cells.4) We also applied this system to dogs with or without renal failure. We found high removal capacity of indoxyl sulfate from circulating blood of renal failure dog with a few adverse reactions.Thus, we succeeded to develop a novel hybrid artificial kidney with proximal tubular cells over-expressing OAT-3. This system may be useful to remove uremic toxins which can not be removed by conventional hemodialysis.