title: Altered glomerular permselectivity to neutral dextrans and heteroporous membrane modeling in human pregnancy.
abstract: Hyperfiltration precedes renal function loss in several nephropathies. Animal studies suggest this may be due to accompanying increases in transglomerular capillary hydrostatic pressure difference (delta P) and/or altered glomerular processing of macromolecules. Renal hemodynamics increase strikingly in human pregnancy. To test the hypothesis that these alterations are not potentially harmful, clearances of inulin, p-aminohippurate, and neutral dextrans were measured at 16- and 36-wk gestation, then 4 mo postpartum, in 11 normotensive women. Results were analyzed using two computer modeling programs. Glomerular filtration rate and renal plasma flow (RPF) were markedly elevated in early and late pregnancy (135 +/- 6 and 895 +/- 53 and 135 +/- 6 and 754 +/- 32 ml/min, respectively, vs. 87 +/- 7 and 520 +/- 17 ml/min postpartum). Gestational hyperfiltration was primarily due to RPF increments with a minor contribution from decrements in capillary oncotic pressure. Fractional dextran clearances (particularly the smaller dextrans, 30-39 A radii) were lower in early pregnancy, decreasing further in late pregnancy. There was no evidence of increased delta P and alterations in glomerular membrane porosity resolved postpartum. These data provide a database by which to study effects of pregnancy on chronic renal disease.
authors.affiliation: Department of Obstetrics, University of Newcastle upon Tyne, United Kingdom.
authors.forename: M
authors.initials: M
authors.lastname: Roberts
authors.forename: M D
authors.initials: MD
authors.lastname: Lindheimer
authors.forename: J M
authors.initials: JM
authors.lastname: Davison
mesh_terms: D000328:Adult; D000419:Albuminuria / Q000652:urine; D003911:Dextrans / Q000493:pharmacokinetics*; D005260:Female; D006439:Hemodynamics; D006801:Humans; D007668:Kidney / Q000502:physiology; D007678:Kidney Glomerulus / Q000378:metabolism*; D008954:Models, Biological; D010539:Permeability; D011247:Pregnancy / Q000378:metabolism*; D011507:Proteinuria / Q000652:urine
chemical_list: D003911:Dextrans