Journal Article

Incubation of porcine high-density lipoprotein with the apical surface of LLC-PK1 renal tubular cells sustains the properties of orientated monolayers

C. P. Streather, J. S. Owen, B. M. Hendry and J. E. Scoble

in Nephrology Dialysis Transplantation

Published on behalf of European Renal Association - European Dialysis and Transplant Assoc

Volume 11, issue 3, pages 431-437
Published in print March 1996 | ISSN: 0931-0509
e-ISSN: 1460-2385 | DOI: http://dx.doi.org/10.1093/oxfordjournals.ndt.a027307
Incubation of porcine high-density lipoprotein with the apical surface of LLC-PK1 renal tubular cells sustains the properties of orientated monolayers

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Background.

HDL is present in the urine of patients with the nephrotic syndrome. The amount of HDL is directly related to the protein selectivity and therefore to the renal prognosis. Urinary HDL may therefore be involved in the pathogenesis of progressive renal impairment in proteinuric renal disease.

Methods.

LLC-PK1 cells were grown as orientated monolayers on filters. Uptake of HDL and permeability to inulin were measured. The influence of HDL in the growth medium on monolayer resistance, protein content, and sodium dependent glucose transport was studied. The effects of tetranitromethane (TNM) nitrosylation of HDL and of albumin, mevalonate, or simvastatin were investigated.

Results.

Confluent LLC-PK1 monolayers took up fluorescently labelled HDL from either epithelial surface and formed a significant diffusion barrier to inulin. Monolayers incubated in 300 μg/ml HDL achieved a protein content and plateau of resistance equal to those in 10% fetal calf serum (FCS); 30–1000 μg/ml HDL applied to the apical surface of confluent monolayers maintained a plateau of resistance as well as 10%, FCS and significantly better than serum-free medium. Sodium-dependent glucose transport was preserved in monolayers exposed to HDL. Simvastatin completely, and nitrosylation partially, removed the stimulatory properties of HDL. These were partly reproduced by albumin or mevalonate.

Conclusions.

HDL can enter renal epithelial cells from the apical surface. HDL added to this surface at confluence, reproducing the conditions found in the nephrotic syndrome, had a measurable positive effect on monolayer resistance. Results with nitrosylated HDL and HMG-CoA blockade suggest that these effects may be mediated via receptors and this enzyme system.

Keywords: apical surface; HDL; LLC-PK1; monolayer resistance; tubular cells; nephrotic syndrome

Journal Article.  0 words. 

Subjects: Nephrology

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