title: Changes in free water fraction and aquaporin function with dwell time during continuous ambulatory peritoneal dialysis.
abstract: Diffusive (K(BD), A₀/Δx(t)) transport parameters and sieving coefficients (S) for small solutes and free water fraction (FWF), that is, the fraction of total water flow that is transported through aquaporins, were assessed as functions of dwell time t for 35 continuous ambulatory peritoneal dialysis patients using glucose 3.86% dialysis fluid.The individual values of the unrestricted pore area over diffusion distance, A₀/Δx(t), were estimated using the mixed effects nonlinear regression and applied for evaluation of S(t) for sodium and FWF(t). FWF decreased on average from the initial 51% of the total transcapillary water flow to 36% at 120 min, whereas the small pore water fraction and sodium sieving coefficient increased. Our results were consistent with the three-pore model if the contribution of the transcellular pores (α(TP)) at the beginning of dwell study was doubled and later decreased to the standard value of 0.02.We conclude that transport characteristics of fluid and small solutes should be considered as time-dependent variables during the peritoneal dialysis.
authors.affiliation: Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences,Warsaw, Poland. jstachowska@ibib.waw.pl
authors.forename: Joanna
authors.initials: J
authors.lastname: Stachowska-Pietka
authors.forename: Jacek
authors.initials: J
authors.lastname: Waniewski
authors.forename: Edward
authors.initials: E
authors.lastname: Vonesh
authors.forename: Bengt
authors.initials: B
authors.lastname: Lindholm
mesh_terms: D000328:Adult; D000368:Aged; D020346:Aquaporins / Q000378:metabolism*; D001692:Biological Transport; D004058:Diffusion; D006801:Humans; D008875:Middle Aged; D010531:Peritoneal Dialysis, Continuous Ambulatory; D012189:Retrospective Studies; D012964:Sodium / Q000378:metabolism; D013997:Time Factors; D014867:Water / Q000378:metabolism*
chemical_list: D020346:Aquaporins; D014867:Water; D012964:Sodium