Efficacy and Biocompatibility of Neutral Icodextrin Peritoneal Dialysis Fluid.

Neutral icodextrin peritoneal dialysis (PD) fluid (n-ICO) has become available for use in Japan. However, removal of water and solutes remains to be elucidated in detail. The present study was designed to determine removal of water, electrolytes, and small, middle, and large molecules in a period of 16 hours. In addition, biocompatibility with respect to peritoneal mesothelial cells was determined.Three stable patients undergoing PD at Tohoku University Hospital were administered n-ICO. Water removal was monitored every 2 hours. Sodium, urea nitrogen [molecular weight (MW): 28 Da], uric acid (MW: 168 Da), β₂-microglobulin [β2M (MW: 11,800 Da)], α₁-microglobulin [α1M (MW: 33,000 Da)], albumin (MW: 66,000 Da), and immunoglobulin G (MW: 160,000 Da) were measured in plasma and dialysate.Primary human peritoneal mesothelial cells were collected from 6 patients. Equal numbers of cells were seeded into 96-well culture plates and cultured for 12 hours. Culture medium was then replaced with dialysate, and 24-hour cell proliferation was determined by WST-1 assay.Water removal was sustained for 16 hours with n-ICO. The Na concentration in effluent did not change over that time. Small molecules such as urea nitrogen and uric acid were rapidly removed. Thus, their dialysate-to-plasma concentration ratio (D/P) approached 1.0 (equilibrium) in 2 - 4 hours. The D/P values for the larger molecules β2M and α1M were 0.4 and less than 0.1 respectively at 16 hours. However, larger molecules were removed in a time-dependent manner.Cell proliferation with n-ICO PD fluid was not different from that with lactate-buffered glucose PD fluid, but was increased from that with acidic icodextrin PD fluid (a-ICO).Water and solute removal with the new n-ICO is not much different from that with a-ICO. However, biocompatibility as reflected by cell proliferation was superior under n-ICO than under a-ICO and equal to proliferation under glucose PD fluid.