Development of bio-artificial kidney

阴离子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这些毒素。大多数毒素，如吲哚硫酸盐，是通过健康人近端肾小管细胞中的有机阴离子转运蛋白3(OAT-3)分泌的。为了开发一种新型的杂交人工肾，将高表达OAT-3的近端小管细胞培养在中空纤维上，我们进行了以下实验：1)我们建立了高表达OAT-3的培养近端小管细胞。我们通过Western印迹和免疫组织化学证实了细胞中有更高的吲哚硫酸盐转运和蛋白的表达。2)我们成功地将细胞接种到中空纤维模块上，这是我们之前报道的。3)我们发现该系统在体外对吲哚硫酸盐有更高的选择性。硫代吲哚的清除量为38ml/min/m2，是对照细胞的8倍。4)我们还将该系统应用于有或无肾功能衰竭的犬。我们发现从肾衰犬循环血中去除吲哚硫酸盐的能力很高，不良反应很少。因此，我们成功地开发了一种新型的近端肾小管细胞高表达OAT-3的杂交人工肾。该系统可用于清除常规血液透析无法清除的尿毒症毒素。

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.