Urinary excretion of oxidative metabolites of bilirubin in subjects with Gilbert syndrome.
OBJECTIVE
Bilirubin is a potent endogenous antioxidant substance. Recent data suggest a direct relationship exists between urinary excretion of biopyrrins, a novel group of bilirubin oxidative metabolites, and severity of oxidative stress. The aim of this study was to evaluate urinary excretion of biopyrrins in subjects with Gilbert syndrome.


METHODS
The study included patients with Gilbert syndrome (n = 33) and healthy blood donors (n = 25). In all subjects complete biochemical tests were conducted along with analysis of urinary excretion of biopyrrins. Linear and logistic regression analyses were used for multiple adjustments of possible confounders/modifiers.


RESULTS
As expected, high serum bilirubin levels were found in the Gilbert syndrome group as compared to controls (27.8 +/- 9.7 vs 9.9 +/- 3.0 micromol/L, P < 0.001). In contrast, urinary levels of biopyrrins were substantially lower in the Gilbert syndrome group as compared to normobilirubinemic control subjects (19.9 +/- 26.0 vs 90.2 +/- 139.1 U/g urinary creatinine, P < 0.001). The Gilbert syndrome group also had very low prevalence odds ratios for urinary biopyrrins above the median of the control values even after adjustment for possibly confounding factors (odds ratio 0.18, 95% confidence interval 0.33-0.94; P = 0.042).


CONCLUSIONS
An inverse relationship was demonstrated between serum bilirubin level and urinary excretion of biopyrrins, which is presumably due to antioxidative effects of elevated serum bilirubin levels in Gilbert syndrome.
Vítek
Libor
L
Institute of Clinical Biochemistry and Laboratory Diagnostics, First Medical Faculty, Charles University, Prague, Czech Republic. vitek@cesnet.cz
Kráslová
Ivana
I
Muchová
Lucie
L
Novotný
Ladislav
L
Yamaguchi
Tokio
T
D000328:Adult; D001663:Bilirubin / Q000097:blood*; D004177:Dipyrone / Q000652:urine*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005878:Gilbert Disease / Q000652:urine*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012044:Regression Analysis; D018709:Statistics, Nonparametric
D004177:Dipyrone; D001663:Bilirubin