Abstract
Background
Acute kidney injury (AKI) is a common complication in critically ill patients. Urinary excretion of liver-type fatty acid-binding protein (L-FABP), which is expressed in the proximal tubules, reflects the presence of tubular injury. Urinary excretion of podocalyxin (PCX), a glycoprotein prominently expressed on podocytes, is associated with podocyte injury. Our aims were to evaluate the utility of urinary L-FABP for the early detection of AKI and to examine whether podocyte injury is present in AKI patients using the biomarker of urinary PCX.
Methods
Patients admitted to the intensive care unit (ICU) were divided into the AKI group (n = 14) and non-AKI group (n = 11), according to the occurrence of AKI during hospitalization in the ICU. Changes in various biomarkers were evaluated.
Results
In the AKI group, elevation of urinary L-FABP level [maximum value of L-FABP, 199.0 (92.5–433.6) μg/g creatinine, median (25–75% interquartile range)], which reflects tubular injury (area under the curve 0.95, cut-off value 44.1 μg/g Cr), occurred between −30 and 0 h before the occurrence of AKI (i.e., the time at which serum creatinine peaked), and elevation of urinary PCX level [maximum value of PCX, 389.5 (267.0–501.0) μg/g creatinine; upper limit of reference value, 160 μg/g creatinine] occurred during the time of recovery from AKI when serum creatinine levels were decreasing between 34.0 and 72.0 h after the occurrence of AKI. Furthermore, a parameter with the primary large AUC for predicting the onset of AKI was urinary L-FABP.
Conclusions
Our study suggests that L-FABP is a useful biomarker for early detection of AKI and that podocyte injury was induced during the recovery phase of AKI.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Kellum JA. Acute kidney injury. Crit Care Med. 2008;36(Suppl 4):S141–5.
Portilla D, Dent C, Sugaya T, Nagothu KK, Kundi I, Moore P, et al. Liver fatty acid-binding protein as a biomarker of acute kidney injury after cardiac surgery. Kidney Int. 2008;73:465–72.
Nakamura T, Sugaya T, Node K, Ueda Y, Koide H. Urinary excretion of liver-type fatty acid-binding protein in contrast medium-induced nephropathy. Am J Kidney Dis. 2006;47:439–44.
Lo LJ, Go AS, Chertow GM, McCulloch CE, Fan D, Ordonez JD, et al. Dialysis-requiring acute renal failure increases the risk of progressive chronic kidney disease. Kidney Int. 2009;76:893–9.
Andersson M, Nilsson U, Hjalmarsson C, Haraldsson B, Nystrom JS, et al. Mild renal ischemia-reperfusion reduces charge and size selectivity of the glomerular barrier. Am J Physiol Renal Physiol. 2007;292:F1802–9.
Hara M, Yamamoto T, Yanagihara T, Takada T, Itoh M, Adachi Y, et al. Urinary excretion of podocalyxin indicates glomerular epithelial cell injuries in glomerulonephritis. Nephron. 1995;69:397–403.
Hara M, Yanagihara T, Kihara I, Higashi K, Fujimoto K, Kajita T. Apical cell membranes are shed into urine from injured podocytes: a novel phenomenon of podocyte injury. J Am Soc Nephrol. 2005;16:408–16.
Kamijo A, Kimura K, Sugaya T, Yamanouchi M, Hikawa A, Hirano N, et al. Urinary fatty acid-binding protein as a new clinical marker of the progression of chronic renal disease. J Lab Clin Med. 2004;143:23–30.
Hara M, Yanagihara T, Itoh M, Matsuno M, Kihara I. Immunohistochemical and urinary markers of podocyte injury. Pediatr Nephrol. 1998;12:43–8.
Pagtalunan ME, Olson JL, Tilney NL, Meyer TW. Late consequences of acute ischemic injury to a solitary kidney. J Am Soc Nephrol. 1999;10:366–73.
Kamijo A, Sugaya T, Hikawa A, Okada M, Okumura F, Yamanouchi M, et al. Urinary excretion of fatty acid-binding protein reflects stress overload on the proximal tubules. Am J Pathol. 2004;165:1243–55.
Yamamoto T, Noiri E, Ono Y, Doi K, Negishi K, Kamijo A, et al. Renal L-type fatty acid-binding protein in acute ischemic injury. J Am Soc Nephrol. 2007;18:2894–902.
Kamijo-Ikemori A, Sugaya T, Obama A, Hiroi J, Miura H, Watanabe M, et al. Liver-type fatty acid-binding protein attenuates renal injury induced by unilateral ureteral obstruction. Am J Pathol. 2006;169:1107–17.
Kamijo-Ikemori A, Sugaya T, Sekizuka A, Hirata K, Kimura K. Amelioration of diabetic tubulointerstitial damage in liver-type fatty acid-binding protein transgenic mice. Nephrol Dial Transpl. 2009;24:788–800.
Yokoyama T, Kamijo-Ikemori A, Sugaya T, Hoshino S, Yasuda T, Kimura K. Urinary excretion of liver type fatty acid binding protein accurately reflects the degree of tubulointerstitial damage. Am J Pathol. 2009;174:2096–106.
Kato K, Sato N, Yamamoto T, Iwasaki YK, Tanaka K, Mizuno K. Valuable markers for contrast-induced nephropathy in patients undergoing cardiac catheterization. Circ J. 2008;72:1499–505.
Acknowledgments
We thank Ms. Seiko Hoshino and Aya Sakamaki for assistance with the collection of urine and serum samples and for measuring urinary parameters. We would also like to thank Dr. Tokuichirou Nagata for obtaining informed consent from the patients. This study was approved by the ethics committee of St. marianna University School of Medicine Hospital, and was in adherence with the Declaration of Helsinki. No financial support was received for this study.
Conflict of interest
None declared.
Author information
Authors and Affiliations
Corresponding author
About this article
Cite this article
Matsui, K., Kamijo-Ikemori, A., Hara, M. et al. Clinical significance of tubular and podocyte biomarkers in acute kidney injury. Clin Exp Nephrol 15, 220–225 (2011). https://doi.org/10.1007/s10157-010-0384-y
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10157-010-0384-y