Functional and ultrastructural effects of essential fatty acid deficiency in kidney epithelial cells

Madin-Darby canine kidney (MDCK) epithelial cells were grown in culture medium supplemented with 1% fetal bovine serum (FBS) to provide a cell culture model of essential fatty acid deficiency (EFAD). 5,8,11-Eicosatrienoic acid (20:3n-9) accumulated in cellular phospholipids, and arachidonic acid (20:4) decreased. A large increase in cellular cholesterol/phospholipid ratio was observed. Hemicyst formation was greatly reduced from normal levels in the EFAD-MDCK cells. Scanning and transmission electron microscopy revealed that EFAD-MDCK were much flatter than their normal counterparts. They had much less dense surface microvilli, mitochondria and other organelles were very sparse, except in the perinuclear area, and much of the peripheral cytoplasm was amorphous. The EFAD was rapidly reversed by the addition of as little as 10 microM linoleic or arachidonic acid to the medium. Cells supplemented with 10% FBS, the usual culture condition, displayed borderline EFAD, with intermediate levels of 20:3n-9 and 20:4 and hemicyst formation. These studies suggest that EFAD reduces water and electrolyte transport in renal tubular epithelium.