Abstract
Background
C-terminal agrin fragment (CAF, size 22 kDa) is a promising new biomarker for kidney function. This study evaluated the usefulness of CAF as a serum biomarker for residual renal function (RRF) in patients undergoing automated peritoneal dialysis (APD).
Patients and methods
Serum, urine and dialysate samples were obtained in 12 end-stage renal disease patients undergoing APD. Total, renal and peritoneal clearances were calculated for CAF, creatinine, blood urea nitrogen (BUN) and cystatin c. kt/V was computed, and RRF (in ml/min) was calculated as the arithmetic mean of creatinine and BUN clearance. Correlations between the biomarkers’ serum concentrations, clearances, kt/V and RRF were computed.
Results
Serum CAF concentrations were highly correlated with serum concentrations of creatinine (r = 0.806, p = 0.002), BUN (r = 0.727, p = 0.007), cystatin c (r = 0.839, p = 0.001) and inversely to 24-h urinary output (r = −0.669, p = 0.017). RRF was inversely correlated with serum concentrations of CAF, cystatin c and creatinine being highest for CAF (r = −0.734, p = 0.007) followed by cystatin c (r = −0.65, p = 0.022) and creatinine (r = −0.606, p = 0.037). Serum BUN was not significantly associated with RRF (r = −0.497, p = 0.101). Age, weight and gender did not significantly affect serum CAF concentrations.
Conclusion
Serum CAF provides a robust serum biomarker for RRF in peritoneal dialysis patients undergoing APD, possibly outperforming the value of conventional biomarkers.
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Acknowledgments
We thank Paul R. Albert, PhD, University of Ottawa, for revision of the manuscript.
Conflict of interest
Stefan Hettwer and Pius Dahinden are currently employed by Neurotune AG, Schlieren, Switzerland. The remaining authors of this manuscript have no conflicts of interest to disclose as described by the journal.
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Steubl, D., Hettwer, S., Dahinden, P. et al. C-terminal agrin fragment (CAF) as a serum biomarker for residual renal function in peritoneal dialysis patients. Int Urol Nephrol 47, 391–396 (2015). https://doi.org/10.1007/s11255-014-0852-5
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DOI: https://doi.org/10.1007/s11255-014-0852-5