The Role of Caveolae on Albumin Passage through Glomerular Endothelial and Epithelial Cells: The New Etiology of Urinary Albumin Excretion.

The Role of Caveolae on Albumin Passage through Glomerular Endothelial and Epithelial Cells: The New Etiology of Urinary Albumin Excretion. Contrib Nephrol. 2018;195:1-11 Authors: Moriyama T, Karasawa K, Nitta K Abstract BACKGROUND: In the traditional theory of albuminuria, small amounts of albumin pass through the fenestrae in glomerular endothelial cells, then through the slit membrane in the gaps between foot processes of glomerular epithelial cells. In the novel theory, large amounts of albumin pass through glomerular capillaries and are taken up by megalin and cubilin receptors on tubular epithelial cells. These etiologies of urinary albumin excretion are still controversial, and the details of albumin passage through the three layers of glomerular capillaries (glomerular endothelial cells, basement membrane, and epithelial cells) have never been entirely elucidated. SUMMARY: Recent advances in basic research have shown that caveolae, which are cell invaginations located on the surface of both glomerular endothelial and epithelial cells, play pivotal roles in the endocytosis, transcytosis, and exocytosis of albumin. Albumin enters into glomerular endothelial and epithelial cells through caveolae; subsequent transcytosis of albumin is not actin- or microtubule-dependent in glomerular endothelial cells, but is actin-dependent in glomerular epithelial cells. Exocytosis of albumin in glomerular endothelial cells occurs via e...
Source: Contributions to Nephrology - Category: Urology & Nephrology Tags: Contrib Nephrol Source Type: research