Implication of changes in xanthine oxidase activity following hemodialysis

Background: Xanthine oxidase activity has a key role in the development of oxidative stress and progression of cardiovascular diseases. However, the change of xanthine oxidase activity following hemodialysis and its prognostic impact remain uncertain. Methods: We prospectively included hemodialysis patients and measured their xanthine oxidase activity before and after the index hemodialysis. Association between xanthine oxidase activity and other clinical variables and the impact of change in xanthine oxidase activity following hemodialysis on cardiovascular death were investigated. Results: A total of 46 patients (median 72 years old, 29 men) were included. Among baseline characteristics, alanine aminotransferase was positively correlated with xanthine oxidase activity (p < 0.001) and Kt/V for urea, serum sodium, and bicarbonate were negatively correlated with it. During hemodialysis, a common logarithm of xanthine oxidase activity decreased significantly from 1.16 (0.94, 1.27) to 1.03 (0.80, 1.20) (p < 0.01). Of them, xanthine oxidase activity remained unchanged or increased in 16 patients, who had a greater decrease in blood pressure and more hemoconcentration compared with those with decreased xanthine oxidase activity. Two–year survival from cardiovascular death was not significantly stratified by the changes in xanthine oxidase activity (p = 0.43). Conclusions: Baseline xanthine oxidase activity was enhanced in the hemodialysis patients compared with the healthy cohort. During hemodialysis, xanthine oxidase activity decreased among the overall cohort, whereas some patients experienced its increases, which was associated with unstable hemodynamics and hemoconcentration during hemodialysis.