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Updated: Aug 21, 2026

Identification of the Source of Secreted Proteins in the Kidney by Brefeldin A Injection
Published on: November 10, 2021
Could plasma cystatin C be useful as a marker of hemodialysis low molecular weight proteins removal?
Andrea Campo1, Giacomo Lanfranco, Luciana Gramaglia
1Renal Care Unit, S. Lazzaro Hospital, Alba, Italy. andrea_campo@hotmail.com
Background:
Plasma cystatin (pCyst) is a well-assessed tool for measuring renal function, and it could also play a part in hemodialysis adequacy.
Methods:
pCyst and other uremic toxins (urea, creatinine, parathyroid hormone, prolactin) were assessed before and after a dialysis session in 18 hemodialysis patients: 7 on bicarbonate hemodialysis (BHD) and 11 on mixed convective dialysis (MCD; 6 standard hemodiafiltration and 5 acetate-free biofiltration). Plasma levels and reduction ratios (RR) were then compared between the BHD and MCD groups.
Results:
The mean pre-dialysis pCyst level is nearly the same in both groups (5.3 +/- 0.8 vs. 5.7 +/- 1 mg/l, p = ns), although a substantial decrease occurs after MCD only (mean 2.4 +/- 1 vs. 6.2 +/- 2.2 mg/l after BHD, p = 0.002). The mean pCyst RR (PCRR) of 55.5% after MCD is poorly related to prolactin and urea RR, fairly comparable to parathyroid hormone RR and very close to creatinine RR (58.4%).
Conclusions:
Only MCD removes pCyst, but the amount of removal is different for other low molecular weight proteins (prolactin and parathyroid hormone) and similar for creatinine, a classic 'little molecule'. In view of the discrepancy of these findings, the use of pCyst in hemodialysis still seems premature and needs further studies.
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