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Similarity of permeabilities for Ficoll, pullulan, charge‐modified albumin and native albumin across the rat peritoneal membrane
Author(s) -
Asgeirsson D.,
Axelsson J.,
Rippe C.,
Rippe B.
Publication year - 2009
Publication title -
acta physiologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.591
H-Index - 116
eISSN - 1748-1716
pISSN - 1748-1708
DOI - 10.1111/j.1748-1716.2009.01955.x
Subject(s) - pullulan , ficoll , chemistry , polysaccharide , chromatography , albumin , serum albumin , biochemistry , in vitro , peripheral blood mononuclear cell
Aim: Compared to neutral globular proteins, neutral polysaccharides, such as dextran, pullulan and Ficoll, appear hyperpermeable across the glomerular filtration barrier. This has been attributed to an increased flexibility and/or asymmetry of polysaccharides. The present study investigates whether polysaccharides are hyperpermeable also across the continuous capillaries in the rat peritoneum. Methods: In anaesthetized Wistar rats, FITC–Ficoll or FITC–pullulan together with 125 I‐human serum albumin (RISA) or neutralized 125 I‐bovine serum albumin (nBSA) were given intravenously, after which peritoneal dialysis (PD) using conventional PD fluid (Gambrosol 1.5%) was performed for 120 min. Concentrations of FITC‐polysaccharides and radioactive albumin species in plasma and dialysis fluid were analysed with high‐performance size exclusion chromatography and a gamma counter respectively. Transperitoneal clearance values were calculated for polysaccharides in the molecular radius range 36–150 Å, and for RISA and nBSA. Results: Ficoll and pullulan showed more or less identical permeabilities, compared to RISA and nBSA, across the peritoneal membrane. Although RISA‐clearance, 5.50 ± 0.28 (μL min −1 ; ±SEM), tended to be lower than the clearances of Ficoll 36Å (6.55 ± 0.25), pullulan 36Å (6.08 ± 0.22) and nBSA (6.56 ± 0.23), the difference was not statistically significant. This is in contrast to the hyperpermeability exhibited by polysaccharides across the glomerular filtration barrier and also contrasts with the charge selectivity of the latter. Conclusion: The phenomenon of molecular flexibility is more important for a macromolecule’s permeability through the glomerular filter than across the continuous peritoneal capillary endothelium. Furthermore, it seems that charge plays a subordinate role in the steady‐state transport across the combined peritoneal capillary–interstitial barrier.