Physiological aspects of the glomerular filtration barrier
(2015) In Lund University Faculty of Medicine Doctoral Dissertation Series 2015:50.- Abstract
- Proteinuria is associated with progression of kidney disease and is an independent risk factor for cardiovascular
morbidity and mortality. The pathophysiological alterations resulting in proteinuria are obscure, although proteinuria is
often associated with pathological changes in the glomerular filtration barrier (GFB). It is therefore of great interest to
study the physiology of the GFB, in order to be able to prevent or reduce proteinuria.
The studies in this thesis were performed using an in vivo model in anesthetized rats. The rats were cannulated for blood
access and the left ureter cannulated for urine collection through a small abdominal incision. The glomerular permeability
was... (More) - Proteinuria is associated with progression of kidney disease and is an independent risk factor for cardiovascular
morbidity and mortality. The pathophysiological alterations resulting in proteinuria are obscure, although proteinuria is
often associated with pathological changes in the glomerular filtration barrier (GFB). It is therefore of great interest to
study the physiology of the GFB, in order to be able to prevent or reduce proteinuria.
The studies in this thesis were performed using an in vivo model in anesthetized rats. The rats were cannulated for blood
access and the left ureter cannulated for urine collection through a small abdominal incision. The glomerular permeability
was measured using sieving coefficients (θ) for fluorescently labeled Ficoll (FITC-Ficoll) with a molecular radius ranging
from 10Å to 80Å. The rats were infused with FITC-Ficoll, and blood- and urine samples were collected and analyzed
with high performance size exclusion chromatography (HPSEC).
In study I, the GFB charge-selectivity was explored using a negatively charged, conformationally intact anionic Ficoll
(CMI-Ficoll), comparing it to neutral Ficoll, of same Stokes-Einstein (SE) radius. The sieving of CMI-Ficoll was reduced
across the GFB compared to neutral Ficoll for molecules of radius 20-35Å. The GFB was thus found to be negatively
charged. However, the charge was of much less magnitude than previously estimated.
In study II, the proposed effects of systemic infusion of protamine sulfate (PS) and hyaluronidase (Hyase) on the GFB
charge-selectivity were studied. PS and to some extent Hyase, increased the permeability for Ficoll molecules > 50Å, but
had no effect on the charge-selectivity of the GFB.
In study III, the permeability effects of extracellular adult (HbA) and fetal hemoglobin (HbF) were studied, showing
increases in θ for macromolecules (50-80Å in radius) after infusion of HbF, but not after HbA or cyano-inactivated HbF
(CN-HbF) infusions. Tempol (a superoxide radical scavenger) and α-1-microglobulin (A1M; a physiological hemebinding
protein and radical scavenger), both prevented the increase in the permeability of the GFB.
In study IV, the effects of the pro-inflammatory cytokines, TNF-α, Il-1β and IL-6, on the GFB permeability were
studied. TNF-α and Il-1β caused a rapid, reversible, increase in glomerular permeability, while IL-6 generated a more
gradual response. These effects could be inhibited with tempol, showing a reactive oxygen species (ROS) dependency of
the cytokine effects on the GFB permeability. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/5323090
- author
- Sverrisson, Kristinn LU
- supervisor
-
- Bengt Rippe LU
- Daniel Asgeirsson LU
- opponent
-
- Professor Hansell, Peter, Uppsala Universitet
- organization
- publishing date
- 2015
- type
- Thesis
- publication status
- published
- subject
- in
- Lund University Faculty of Medicine Doctoral Dissertation Series
- volume
- 2015:50
- pages
- 84 pages
- publisher
- Njurmedicin, Institutionen för Kliniska Vetenskaper Lund
- defense location
- Segerfalksalen, BMC A10, Sölvegatan 17, Lund
- defense date
- 2015-05-20 09:00:00
- ISSN
- 1652-8220
- ISBN
- 978-91-7619-129-3
- language
- English
- LU publication?
- yes
- id
- 7c46b18a-3152-4940-9bdb-edd088b6dd6a (old id 5323090)
- date added to LUP
- 2016-04-01 13:27:15
- date last changed
- 2019-05-22 01:28:13
@phdthesis{7c46b18a-3152-4940-9bdb-edd088b6dd6a,
abstract = {{Proteinuria is associated with progression of kidney disease and is an independent risk factor for cardiovascular<br/><br>
morbidity and mortality. The pathophysiological alterations resulting in proteinuria are obscure, although proteinuria is<br/><br>
often associated with pathological changes in the glomerular filtration barrier (GFB). It is therefore of great interest to<br/><br>
study the physiology of the GFB, in order to be able to prevent or reduce proteinuria.<br/><br>
The studies in this thesis were performed using an in vivo model in anesthetized rats. The rats were cannulated for blood<br/><br>
access and the left ureter cannulated for urine collection through a small abdominal incision. The glomerular permeability<br/><br>
was measured using sieving coefficients (θ) for fluorescently labeled Ficoll (FITC-Ficoll) with a molecular radius ranging<br/><br>
from 10Å to 80Å. The rats were infused with FITC-Ficoll, and blood- and urine samples were collected and analyzed<br/><br>
with high performance size exclusion chromatography (HPSEC).<br/><br>
In study I, the GFB charge-selectivity was explored using a negatively charged, conformationally intact anionic Ficoll<br/><br>
(CMI-Ficoll), comparing it to neutral Ficoll, of same Stokes-Einstein (SE) radius. The sieving of CMI-Ficoll was reduced<br/><br>
across the GFB compared to neutral Ficoll for molecules of radius 20-35Å. The GFB was thus found to be negatively<br/><br>
charged. However, the charge was of much less magnitude than previously estimated.<br/><br>
In study II, the proposed effects of systemic infusion of protamine sulfate (PS) and hyaluronidase (Hyase) on the GFB<br/><br>
charge-selectivity were studied. PS and to some extent Hyase, increased the permeability for Ficoll molecules > 50Å, but<br/><br>
had no effect on the charge-selectivity of the GFB.<br/><br>
In study III, the permeability effects of extracellular adult (HbA) and fetal hemoglobin (HbF) were studied, showing<br/><br>
increases in θ for macromolecules (50-80Å in radius) after infusion of HbF, but not after HbA or cyano-inactivated HbF<br/><br>
(CN-HbF) infusions. Tempol (a superoxide radical scavenger) and α-1-microglobulin (A1M; a physiological hemebinding<br/><br>
protein and radical scavenger), both prevented the increase in the permeability of the GFB.<br/><br>
In study IV, the effects of the pro-inflammatory cytokines, TNF-α, Il-1β and IL-6, on the GFB permeability were<br/><br>
studied. TNF-α and Il-1β caused a rapid, reversible, increase in glomerular permeability, while IL-6 generated a more<br/><br>
gradual response. These effects could be inhibited with tempol, showing a reactive oxygen species (ROS) dependency of<br/><br>
the cytokine effects on the GFB permeability.}},
author = {{Sverrisson, Kristinn}},
isbn = {{978-91-7619-129-3}},
issn = {{1652-8220}},
language = {{eng}},
publisher = {{Njurmedicin, Institutionen för Kliniska Vetenskaper Lund}},
school = {{Lund University}},
series = {{Lund University Faculty of Medicine Doctoral Dissertation Series}},
title = {{Physiological aspects of the glomerular filtration barrier}},
volume = {{2015:50}},
year = {{2015}},
}