albumin - publications

Predict more albumin - ligand interactions now!

1. J Am Soc Nephrol. 2012 Jan 26. [Epub ahead of print]

Generation of Urinary Albumin Fragments Does Not Require Proximal Tubular Uptake.

Weyer K, Nielsen R, Christensen EI, Birn H.

Department of Biomedicine, Aarhus University, Aarhus, Denmark.

Urinary albumin excretion is an important diagnostic and prognostic marker of
renal function. Both animal and human urine contain large amounts of albumin
fragments, but whether these fragments originate from renal tubular degradation
of filtered albumin is unknown. Here, we used mice with kidneys lacking megalin
and cubilin, the coreceptors that mediate proximal tubular endocytosis of
albumin, to determine whether proximal tubular degradation of albumin forms the
detectable urinary albumin fragments. After intravenous administration of
(125)I-labeled mouse albumin to knockout and control mice, we examined kidney
uptake of albumin and urinary excretion of both intact albumin and its fragments
using size exclusion chromatography. In control mice, all labeled albumin eluted
as albumin fragments in the urine. In megalin/cubilin-deficient mice, we observed
decreased uptake and degradation of albumin and increased urinary excretion of
intact albumin; we did not, however, detect a decrease in the excretion of
albumin fragments. These results show that the generation of urinary albumin
fragments occurs independently of renal tubular uptake and degradation of
albumin, suggesting that the pathophysiological implications of changes in
urinary albumin fragments require reevaluation.

PMID: 22282591 [PubMed - as supplied by publisher]