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Kidney Week

Abstract: SA-PO452

Urinary CD80 as a Novel Biomarker of Podocyte Injury

Session Information

  • Pediatric Nephrology - II
    October 27, 2018 | Location: Exhibit Hall, San Diego Convention Center
    Abstract Time: 10:00 AM - 12:00 PM

Category: Pediatric Nephrology

  • 1600 Pediatric Nephrology

Authors

  • Tsuji, Shoji, Kansai Medical University, Hirakata-shi, Japan
  • Akagawa, Yuko, Kansai Medical University, Hirakata-shi, Japan
  • Kimata, Takahisa, Kansai Medical University, Hirakata-shi, Japan
  • Yamanouchi, Sohsaku, Kansai Medical University, Hirakata-shi, Japan
  • Akagawa, Shohei, Kansai Medical University, Hirakata-shi, Japan
  • Kaneko, Kazunari, Kansai Medical University, Hirakata-shi, Japan
Background

CD80, which is expressed by antigen-presenting cells, was recently reported to also be expressed in podocytes in pathological conditions such as idiopathic nephrotic syndrome (INS); moreover, CD80 over-expression could be detected in urine (Reiser J, et al. 2004; Garin, EH, et al. 2009). However, as there are many skeptical reports, a conclusion has yet to be drawn. The purpose of this study was to clarify whether podocyte-derived CD80 appears in urine, where it may serve as a biomarker for podocyte disorder.

Methods

Patients with INS (median age 7.9 years, n=10) were grouped into initial attack and relapse (group A), and remission (group B), and compared with patients with other renal diseases (e.g., IgA vasculitis nephritis; median age 8.2 years, n=7; group C). Single voided urine and serum samples were collected at the same time. Urine and serum CD80 levels were measured by ELISA and compared among the three groups to examine potential correlations. The correlation between urine CD80 and urinary protein excretion was also investigated. In addition, puromycin was added to a human podocyte cell line to prepare an in vitro INS model, and expression of CD80 after 72 hours was confirmed using western blotting.

Results

(1) Urinary CD80 was significantly increased in group A compared with group B (group A:group B=465.94:0.00; ng/gCre, numerical value is median, p=0.0072). Group A was also higher than group C, however there was no significant difference (group A:group C=465.94:422.04, p=0.65).
(2) Although there was no significant correlation between urinary CD80 and serum CD80 values, there was a correlation between urinary CD80 and urinary protein excretion (r=0.24, p=0.17; r=0.35, p=0.0031, respectively).
(3) As a result of administration of puromycin to the human podocyte cell line, CD80 expression was increased almost two-fold compared with control (untreated podocytes: puromycin-treated poocytes=8201.26:16309.43, p=0.015).

Conclusion

A significant amount of CD80 was excreted in the urine of INS and other renal disease patients, and its concentration did not correlate with serum concentration. In addition, CD80 expression was also confirmed in an INS human cell line model. Furthermore, urinary CD80 was significantly correlated with amount of urinary protein reflecting podocyte injury, suggesting that it could be a biomarker of podocyte disorder.