Severe intraglomerular detachment of podocytes in a Gitelman syndrome patient.

Abstract

We report the case of a 38-year-old woman diagnosed with Gitelman syndrome. A kidney biopsy showed abundant floating cells in the Bowman's space of the mildly cystic glomeruli, moderate tubulointerstitial changes and apparent intimal thickening of small arteries. These floating cells were immunohistologically identified as podocytes, by the expression of podocalyxin, vimentin, Wilms' tumor 1, synaptopodin and nephrin with positivities of 100%, 88.4%, 80.4%, 74.7% and 22.6%, respectively. In these phenotypes, nephrin expression was notably decreased in both detached and capillary-attached podocytes in comparison with normal control podocytes. Immunostaining of both detached and capillary-attached podocytes for Bax, Bcl-2, desmin, fibroblast-specific protein-1, α-smooth muscle actin and Ki-67 was negative, as were TUNEL assays. These results suggest that apoptosis and epithelial-mesenchymal transition were not the main cause of podocyte detachment in this patient. In addition, levels of urinary podocalyxin were not elevated, suggesting the detached podocytes were not excreted in the urine. To the best of our knowledge, this is the first report of severe intraglomerular non-apoptotic detachment of podocytes in Gitelman syndrome. This podocyte detachment may be associated with nephron obstruction and reduced nephrin expression.

• Authors: Naoki Takahashi, Hideki Kimura, Shinichi Mizuno, Masanori Hara, Yoshiaki Hirayama, Hiroyuki Kurosawa, Shouji Tsutaya, Minoru Yasujima, Seiji Yokoi, Daisuke Mikami, Kenji Kasuno, Hironobu Naiki, Masayuki Iwano, Haruyoshi Yoshida
• Journal: Clinical and experimental nephrology (Clin Exp Nephrol) Vol. 16 Issue 3 Pg. 495-500 (Jun 2012) ISSN: 1437-7799 [Electronic] Japan
• PMID: 22484642 (Publication Type: Case Reports, Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Membrane Proteins
• Sialoglycoproteins
• nephrin
• podocalyxin

Topics

• Adult
• Female
• Gitelman Syndrome (pathology)
• Humans
• Kidney Glomerulus (pathology)
• Membrane Proteins (biosynthesis)
• Podocytes (metabolism, pathology)
• Sialoglycoproteins (biosynthesis)