Cellular Physiology and Biochemistry (Feb 2018)

Massive Proteinuria-Induced Injury of Tubular Epithelial Cells in Nephrotic Syndrome is Not Exacerbated by Furosemide

  • Shujun Wang,
  • Qingjun Pan,
  • Chen Xu,
  • Jun-jia Li,
  • Hao-Xuan Tang,
  • Ting Zou,
  • Kai-peng Jing,
  • Lin Ye,
  • Hong-Luan Wu,
  • Wei-jing Liu,
  • Hua-feng Liu

DOI
https://doi.org/10.1159/000487776
Journal volume & issue
Vol. 45, no. 4
pp. 1700 – 1706

Abstract

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Background/Aims: Massive proteinuria, a significant sign of nephrotic syndrome (NS), has the potential to injure tubular epithelial cells (TECs). Furosemide is widely used for the treatment of edema, a common manifestation of NS. However, whether furosemide treatment affects massive proteinuria-induced TEC injury in patients with NS is unknown. Methods: The effect of furosemide on TEC damage was investigated in vitro. In addition, a clinical study was conducted to study whether the short-term treatment of nephrotic edema with furosemide could exacerbate TEC injury. Results: The proliferation of in vitro human kidney-2 (HK-2) cells exposed to massive urinary protein (8 mg/mL) significantly decreased (P<0.05), while the levels of kidney injury molecule-1 (Kim-1) and neutrophil gelatinase associated lipocalin (NGAL) in the supernatants significantly increased (P<0.05). Importantly, furosemide treatment did not further increase the expression of Kim-1 and NGAL in HK-2 cells upregulated by massive proteinuria. For the clinical study, 26 patients with NS, all prescribed the recommended dosage of prednisone (1 mg/kg/day), were randomly assigned to two groups. One group (n=13) received furosemide (60-120 mg/day, intravenously) for 1 week; the remaining participants (control group) did not receive furosemide or any other diuretics. The results showed that the 24-h urine volume in the furosemide-treated group was slightly, but not significantly, higher than that in the control group (P>0.05). In addition, serum levels of BUN, Scr, Cys C, and urinary Kim-1 and NGAL were not significantly different between the two groups (all P>0.05). Twenty-three patients underwent a renal biopsy. Of these, 22 patients exhibited vacuolar degeneration of the TECs; 8 patients showed brush border membrane shedding of the TECs; and 12 patients showed protein casts. However, there were no significant differences between the two groups (all P>0.05). Conclusion: In summary, massive proteinuria induced the injury of TECs in patients with NS, and furosemide treatment did not aggravate this injury.

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