Imbalance between production and scavenging of hydroxyl radicals in patients maintained on hemodialysis

Background Reactive oxygen species are as being related to the pathophysiology of endstage renal disease (ESRD). We measured the plasma hydroxyl radical (·OH)-producing ability and ·OH-scavenging activity in patients with ESRD to clarify the pathophysiological states involved. Methods We used electron spin resonance to measure plasma N -t-butyl-α-phenylnitron radical spin adduct (pPBN rsa) as ·OH-producing ability and plasma 3,3,5,5-tetramethyl-1-pyrroline- N -oxide radical spin adduct (pM4PO rsa) as ·OH-scavenging activity. Oxidative injuries were evaluated by determining oxidised low-density lipoprotein (Ox-LDL). Results The pPBN rsa of the ESRD patients was lower than that of the controls (1.83 vs 2.94 µmol/g protein). The pM4PO rsa of the ESRD patients was higher than that of the controls (3.85 vs 3.15 mmol l -ascorbic acid 2-[3,4-dihydro-2,5,7,8-tetramethyl-2-(4,8,12-trimethyltridecyl)-2H-1-benzopyran-6-yl hydrogen phosphate] potassium salt (EPC-K 1 )/g protein). The pPBN rsa and pM4PO rsa were correlated, both in the ESRD patients and in the controls ( r = 0.47 and r = 0.53). Ox-LDL was correlated with hemodialysis (HD) duration ( r = 0.49) and was negatively correlated with pPBN rsa ( r = −0.54), which indicates that oxidative stress was increased as HD therapy was prolonged and suppressed pPBN rsa. Conclusions There was an imbalance between ·OH-producing ability and ·OH-scavenging activity, in the ESRD patients, and this may be responsible for compromising the health of ESRD patients.