Serum paraoxonase 1 (PON1) lactonase activity is lower in end-stage renal disease patients than in healthy control subjects and increases after hemodialysis.
BACKGROUND
The mechanism of paraoxonase 1 (PON1) atheroprotective remains elusive. The lactonizing/lactonase activity of PON1 is gaining favor as the most significant in physiology.


METHODS
We studied 42 end-stage renal disease (ESRD) patients undergoing hemodialysis (HD) and 49 control subjects. We measured PON1 lactonase, arylesterase and triesterase activities by kinetic methods.


RESULTS
Serum lactonase activity was 11% lower in ESRD patients (p<0.0001) and did not correlate with high-density lipoprotein (HDL) cholesterol when controlling for confounders. Lactonase activity was significantly higher after dialysis. Using a repeated measure-ANOVA adjusted for the confounders (age, gender, total cholesterol, triglyceride and HDL cholesterol) we show that the changes in lactonase after dialysis were significant (p<0.0001). HD increases lactonase activity to levels indistinguishable from those of control subjects. In simple linear regression analyses we showed a significant inverse correlation between changes in lactonase and those of creatinine by dialysis (r=-0.339, p=0.028).


CONCLUSIONS
ESRD patients maybe more susceptible to lipid peroxidation and to protein homocysteinylation than healthy subjects due to the decreased activity of lactonase. A lower serum lactonase activity would be coupled with delayed catabolism of oxidized phospholipids in low-density lipoprotein and oxidized macrophages, and with greater protein homocysteinylation, accelerating atherogenesis. One mechanism for lower lactonase activity in ESRD patients may be inhibition by uremic toxins and oxidative stress. The pathophysiology of reduced lactonase activity in uremia and the beneficial effects of HD need further investigation.
Glycation, Oxidation and Disease Laboratory, Division of Basic Medical Sciences, Touro University-California, Mare Island, Vallejo, CA 94592, USA. alejandro.gugliucci@tu.edu
Alejandro
A
Gugliucci
Eriko
E
Kinugasa
Kazuhiko
K
Kotani
Russell
R
Caccavello
Satoshi
S
Kimura
D043303:Aryldialkylphosphatase / Q000097:blood*; D016022:Case-Control Studies; D005260:Female; D040361:Healthy People Programs; D006801:Humans; D007676:Kidney Failure, Chronic / Q000201:enzymology* / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D006435:Renal Dialysis
D043303:Aryldialkylphosphatase