Metabolic effects of fatty acid bearing albumin on a proximal tubule cell line.. Schreiner, Mark E. Thomas Aubrey R. Morrison & George F. Renal Division, Washington University School of Medicine, St Louis, Missouri, 63110, USA, CV Therapeutics, Inc., 3172 Porter Drive, Palo Alto, CA, 94304, USA.
APStracts 2:0007F, 1995.
In glomerular disease fatty acids carried on albumin are taken up by the proximal tubule with filtered albumin. We postulate that the fatty acids carried on filtered albumin could contribute to the deleterious effects of proteinuria. The effects of fatty acid-albumin complexes on lipid metabolism have been studied in Opossum kidney (OK) cells, a proximal tubule cell line. OK cells transported two -thirds of 14C-palmitate-albumin (5 mg/ml) intracellularly within 16 hours. 14C-palmitate-albumin was distributed into phosphatidylcholines, phosphatidylinositols, tri- and diglycerides. 14C-labelled unsaturated fatty acid-albumins (oleate, linoleate and arachidonate) showed preferential incorporation into triglycerides, with lesser incorporation into phospholipids. Studies of total lipid pools showed that fatty acid-albumin uptake produced a particularly marked increase in total triglyceride levels (some 10-fold). Oil Red O staining of OK cells cultured with oleate-albumin showed a marked increase in intracellular lipid droplets, compared to cells cultured with delipidated albumin, consistent with triglyceride accumulation. Less than 1% of 14C-palmitate taken up was isolated as intracellular free fatty acid. Less than 5% of 14C-palmitate internalized was oxidized to 14CO2. Different fatty acids, when taken up by the OK cell, have distinct metabolic fates. Each fatty acid is incorporated in a characteristic fashion into certain complex lipids, possibly dependent on the presence or absence of double bonds. We propose that this may have functional consequences for the proximal tubule in the human nephrotic syndrome. 

Received 17 March 1994; accepted in final form 30 January 1995.
APS Manuscript Number F93-4.
Article publication pending Am. J. Physiol. (Renal Fluid Electrolyte
Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 23 February 1995.