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Abstract: TH-PO025

Urinary Uromodulin Level Reflects Tubular Recovery in Patients With AKI

Session Information

Category: Acute Kidney Injury

  • 102 AKI: Clinical‚ Outcomes‚ and Trials

Authors

  • Iwashita, Takatsugu, Department of Nephrology and Hypertension, Saitama Medical Center, Saitama Medical University, Kawagoe, Saitama, Japan
  • Nagayama, Izumi, Department of Nephrology and Hypertension, Saitama Medical Center, Saitama Medical University, Kawagoe, Saitama, Japan
  • Ono, Kazutoshi, Division of Nephrology, Department of Internal Medicine, Jichi Medical University, Shimotsuke, Tochigi, Japan
  • Nagata, Daisuke, Division of Nephrology, Department of Internal Medicine, Jichi Medical University, Shimotsuke, Tochigi, Japan
  • Hasegawa, Hajime, Department of Nephrology and Hypertension, Saitama Medical Center, Saitama Medical University, Kawagoe, Saitama, Japan
  • Maeshima, Akito, Department of Nephrology and Hypertension, Saitama Medical Center, Saitama Medical University, Kawagoe, Saitama, Japan
Background

Uromodulin is the most abundant protein excreted in the urine under physiological conditions. It is exclusively produced by the thick ascending limb of Henle and secreted into the urine via proteolytic cleavage. Uromodulin plays an important role in preventing urinary tract infections and kidney stones. However, it remains unknown whether urinary uromodulin level is correlated with the severity and prognosis of acute kidney injury (AKI). In this study, we investigated whether urinary uromodulin is useful as a biomarker for AKI.

Methods

AKI patients (n=91) who were treated at Jichi Medical University (December 2018 to January 2020) and Saitama Medical Center Saitama Medical University (December 2020 to September 2021) were enrolled. Written consent was obtained from all patients. Serum and urinary uromodulin were measured by ELISA. Correlations of urinary uromodulin level and various clinical parameters were analyzed. This study was approved by the Ethics Committee on Human Research of our institutions (Approval number A18-081, A18-089, No.2472).

Results

Urinary uromodulin level was significantly decreased in AKI patients, compared to that in healthy control (974.9 ± 792.3 vs. 2251.0 ± 942.6 ng/mL, p<0.001). Urinary uromodulin was not correlated with urine protein level, NAG, alpha1-microgloblin, L-FABP, and kidney injury molecule-1. No significant correlation between serum and urinary uromodulin was observed, suggesting that urinary uromodulin is derived from kidney but not from blood. In patient with drug-induced AKI, urinary uromodulin level returned to normal level consistent with improvement of renal function (463.5 to 1974.6 ng/mL). No recovery of urinary uromodulin was observed in AKI patients who required renal replacement therapy and progressed to end stage renal disease.
In case of kidney transplantation recipient, urinary uromodulin was undetectable at 1 day after transplantation, but was markedly increased thereafter (day 42, 558.3 ng/mL).

Conclusion

Urinary uromodulin reflects the quantity of normally functioning renal tubules and may be useful for monitoring the recovery of damaged renal tubules in AKI.