Differential action of plasma and albumin on transcapillary exchange of anionic solute

V. H. Huxley, F. E. Curry, M. R. Powers, B. Thipakorn

Research output: Contribution to journalArticle

36 Scopus citations

Abstract

We tested two hypotheses to account for the reduction in coupling of anionic solute to water flow (solvent drag) in microvessels during perfusion with plasma compared with albumin. Solvent drag is determined by both hydraulic conductivity (L(p)) and solute reflection coefficient (σ). Accordingly, decreased solvent drag during plasma perfusion must be the result of an increase in σ (hypothesis 1) or reduction of L(p) (hypothesis 2) or some combination of both mechanisms. These hypotheses were assessed by measuring L(p), σ, and diffusive solute permeability (P(sd)) to the anionic protein α-lactalbumin in frog mesenteric exchange microvessels during plasma or albumin perfusion. The solute permeability coefficient to α-lactalbumin (P(s)/(α-lactalbumin)) was lower during exposure to plasma than bovine serum albumin (BSA) [(P(s)/(α-lactalbumin))(plasma)/(P(s)/(α-lactalbumin))(BSA) = 0.31 ± 0.11 (means ± SE, n = 9)]. Solute reflection coefficient to α- lactalbumin (σ(α-lactalbumin)) was 0.69 ± 0.02 in plasma and 0.34 ± 0.03 in BSA (n = 7). L(p) was not significantly influenced by perfusate protein composition (L(p)/(plasma)/L(p)/(BSA) = 1.02 ± 0.11; n = 20). These data lead to the conclusion that the actions of plasma are to confer charge selectivity for anionic solute and, to a lesser extent, modify the porous pathways of the microvessel wall. Taken together, these results indicate that porous pathways contribute significantly to macromolecular flux in plasma- perfused vessels.

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume264
Issue number5 33-5
StatePublished - 1993
Externally publishedYes

Keywords

  • α-lactalbumin
  • endothelial barrier
  • glycocalyx
  • microcirculatory exchange
  • microvessels
  • plasma proteins
  • Rana pipiens

ASJC Scopus subject areas

  • Physiology

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