Background: Low-molecular-weight proteins (LMWPs) are substances of molecular weights 10-35 kDa, which accumulate in plasma of patients with end-stage renal disease (ESRD) due to the abolishment of plasma renal filtration. LMWPs are considered as a separate group of uremic toxins.
Aim: The influence of hemodialysis (HD) on the release of some LMWPs from leukocytes was assessed by comparing levels of serum pancreatic-type alkaline RNase and leukocyte-type acid RNase as well as polymorphonuclear (PMN) elastase.
Methods: The mentioned proteins were assayed in 58 ESRD patients on HD prior and after the dialysis session and compared with the results obtained from 36 healthy subjects. The levels of elastase and acid and alkaline RNase were correlated with HD parameters, residual diuresis, predialysis concentrations of serum creatinine, urea and albumin as well as pre- and postdialysis granulocyte count.
Results: Changes in PMN elastase produced by the dialysis session positively correlate with changes in acid RNase levels (r = 0.3650; p = 0.0061), while there is no such correlation for alkaline RNase. There is a negative correlation between pre- and postdialysis differences in levels of acid and alkaline RNases (r = -0.3542; p = 0.008), indicating that HD induces liberation of a factor suppressing alkaline RNase. Levels of acid and alkaline RNase negatively correlate with residual diuresis, indicating its significance in control of LMWP accumulation (r = -0.3970; p = 0.0025; r = -0.2596; p = 0.0533, respectively).
Conclusions: Dialysis treatment causes an increase in both acid leukocyte-type and alkaline pancreatic-type RNase activity in plasma. Dialysis-related increases in acid RNase activity correlate with the respective changes in PMN elastase, which suggests that leukocyte activation during dialysis contributes to an increase in plasma LMWPs.
Copyright 2009 S. Karger AG, Basel.