Total and corrected antioxidant capacity in hemodialyzed patients.
BACKGROUND
Oxidative stress may play a critical role in the vascular disease of end stage renal failure and hemodialysis patients. Studies, analyzing either discrete analytes and antioxidant substances, or the integrated total antioxidant activity of human plasma during hemodialysis, give contradictory results.


METHODS
Recently, we have introduced a new automated method for the determination of Total Antioxidant Capacity (TAC) of human plasma. We have serially measured TAC and corrected TAC (cTAC: after subtraction of the interactions due to endogenous uric acid, bilirubin and albumin) in 10 patients before the onset of the dialysis session, 10 min, 30 min, 1 h, 2 h and 3 h into the procedure and after completion of the session.


RESULTS
Our results indicate that TAC decreases, reaching minimum levels at 2 h. However, corrected TAC increases with t1/2 of about 30 min. We then repeated the measurements in 65 patients undergoing dialysis with different filters (36 patients with ethylene vinyl alcohol copolymer resin filter -Eval-, 23 patients with two polysulfone filters -10 with F6 and 13 with PSN140-, and 6 patients with hemophan filters). Three specimens were collected (0, 30, 240 min). The results of this second group confirm our initial results, while no significant difference was observed using either filter.


CONCLUSIONS
Our results are discussed under the point of view of possible mechanisms of modification of endogenous antioxidants, and the interaction of lipid- and water-soluble antioxidants.
Malliaraki
Niki
N
Departments of Clinical Chemistry, University of Crete, School of Medicine, and University Hospital, Heraklion, GR-71110, Greece. nikim@acn.gr
Mpliamplias
Dimitris
D
Kampa
Marilena
M
Perakis
Kostas
K
Margioris
Andrew N
AN
Castanas
Elias
E
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000418:Albumins / Q000032:analysis; D000704:Analysis of Variance; D000975:Antioxidants / Q000378:metabolism; D001663:Bilirubin / Q000097:blood; D005260:Female; D006400:Hematocrit; D006801:Humans; D007676:Kidney Failure, Chronic / Q000097:blood* / Q000628:therapy; D008055:Lipids / Q000097:blood; D008297:Male; D008875:Middle Aged; D018384:Oxidative Stress; D006435:Renal Dialysis / Q000009:adverse effects* / Q000295:instrumentation; D014527:Uric Acid / Q000097:blood
D000418:Albumins; D000975:Antioxidants; D008055:Lipids; D014527:Uric Acid; D001663:Bilirubin