Plasma xanthine oxidoreductase activity in Japanese patients with type 2 diabetes across hospitalized-treatment.

AIMS Xanthine oxidoreductase (XOR) is an enzyme that catalyzes hypoxanthine and xanthine to xanthine and uric acid, respectively. Plasma XOR activity has recently been measured in human subjects. However, limited information is known about plasma XOR activity in patients with type 2 diabetes (T2DM), and its changes after short-term glycemic control treatment. MATERIALS AND METHODS We enrolled 28 Japanese patients (10 males/18 females) with T2DM who were hospitalized to undergo medical treatment for diabetes. Plasma XOR activity, quantified using triple quadrupole mass spectrometry and liquid chromatography (LC/TQMS), and other clinical parameters were examined at admission and 2 weeks after hospitalized treatment. Changes in plasma XOR activity after hospitalized treatment and associated clinical parameters were assessed. RESULTS At the time of admission, the median plasma XOR activity was 83.1 pmol/h/mL, with a wide range of 14.4-1150 pmol/h/mL. Multiple regression analysis identified serum aspartate transaminase (AST) and alanine transaminase (ALT) levels as significant and independent factors correlating with the baseline plasma XOR. Two weeks of hospitalized treatment was associated with a significant decrease in plasma XOR activity. Changes in serum AST were also the only significant and independent factor correlating with changes in plasma XOR activity. CONCLUSIONS A close relationship was observed between plasma XOR activity and liver transaminases in patients with T2DM, cross-sectionally, and also across hospitalized treatment.