The Changes of Slit Diaphragm Molecules After Using Sirolimus

Choi, Jung-Youn; Han, Gi-Dong; Kim, Yong-Jin; Park, Yong-Hoon

doi:2010.14.2.143

J Korean Soc Pediatr Nephrol > Volume 14(2); 2010 > Article

J Korean Soc Pediatr Nephrol 2010;14(2): 143-153. doi: https://doi.org/10.3339/jkspn.2010.14.2.143

Sirolimus 사용 후 사구체 기저막 세극막 관련 분자의 변화

최정연, 한기동, 김용진, 박용훈

¹영남대학교 의과대학 소아과학교실
²영남대학교 식품공학과
³영남대학교 의과대학 병리학교실
⁴영남대학교 의과대학 소아과학교실

The Changes of Slit Diaphragm Molecules After Using Sirolimus

Jung-Youn Choi, Gi-Dong Han, Yong-Jin Kim, Yong-Hoon Park

¹Department of Pediatrics, College of Medicine, Yeungnam University
²Department of Food Science and Technology, Yeungnam University
³Department of Pathology, College of Medicine, Yeungnam University
⁴Department of Pediatrics, College of Medicine, Yeungnam University

Received: August 26, 2010; Revised: September 21, 2010. Accepted: October 5, 2010.

ABSTRACT

Purpose: Recently, massive proteinuria has been observed in some transplant patients after switching cyclosporine A (CsA) to sirolimus. To evaluate the pathogenesis of sirolimus-associated proteinuria, we investigated the early changes in slit diaphragm molecules by various administrative conditions of sirolimus and CsA.
Methods: In vitro-Mouse podocytes were incubated with buffer (C), sirolimus ($10;{mu}g/mL$) after CsA ($10;{mu}g/mL$) (C-S), sirolimus only (S) and CsA and sirolimus simultaneously (C+S) for 12, 24, and 48 hours. In vivo- twenty four SPF female Wistar rats were divided into 4 groups buffer (C), sirolimus after 2 weeks of CsA (C-S), sirolimus only (S) and CsA and sirolimus simultaneously (C+S). All groups were treated by intraperitoneal injection every other day for 4 weeks (CsA: 25 mg/kg, sirolimus: 0.5 mg/kg). The changes in mRNA of slit diaphragm molecules were examined by RT-PCR.
Results : The mRNA of nephrin was significantly decreased in group C-S and C+S in vitro. In vivo, the mRNA of nephrin in all groups using sirolimus and the mRNA of podocin in group C-S and C+S were decreased. Microscopically, group C-S and C+S showed small vacuolization and calcification in proximal tubular epithelial cells. Immunohistochemistry using nephrin and podocin antibodies did not show remarkable decrease of staining along the glomerular capillaries. Electron-microscopically, focal fusion of foot processes was seen in group C-S and C+S.
Conclusion : This study suggests the decrease of slit diaphragm molecules (nephrin and podocin) in podocyte may be one of the causes of sirolimus associated proteinuria, and podocyte injury by sirolimus may need a primary hit by CsA to develop the proteinuria.

Key words: Sirolimus | Proteinuria | Cyclosporine | Nephrin