AJP - Heart and Circulatory Physiology, Vol 257, Issue 6 1851-H1859, Copyright © 1989 by American Physiological Society
Dialysate to blood transport of macromolecules during peritoneal dialysis
J. K. Leypoldt, A. S. Chiu, R. P. Frigon and L. W. Henderson
Department of Medicine, Veterans Administration Medical Center, San Diego 92161.
Asymmetrical transport of macromolecules between plasma and the peritoneal
cavity results primarily from unidirectional lymphatic removal from the
peritoneal cavity. Recent work suggests, however, that macromolecular
transport across the peritoneal-plasma barrier via the capillary wall
(i.e., the peritoneal membrane) may also be asymmetrical. We determined the
diffusive and convective transport properties for creatinine,
p-aminohippurate, and neutral dextran (13-40 A) across the peritoneal
membrane in the dialysate to blood direction during peritoneal dialysis
using isotonic and hypotonic solutions in awake New Zealand White rabbits.
Values of the diffusive permeability-area product that were calculated
during the isotonic exchange were similar to, yet somewhat smaller than,
those previously determined in the blood to dialysate direction for all
test solutes. Solute reflection coefficients that were calculated during
the hypotonic exchange were variable, yet the resulting mean solute
reflection coefficient values for all the test solutes were similar to
those previously determined in the blood to dialysate direction. We
conclude that asymmetrical peritoneal transport of macromolecules with
radii less than 40 A is not due to asymmetrical transport across the
peritoneal membrane.
