Evaluation of serum arginase I as an oxidative stress biomarker in a healthy Japanese population using a newly established ELISA

Objective: We reported previously that serum arginase I increased in asthmatic patients and was associated with oxidative stress in a small healthy population. However, the exact association of arginase I with oxidative stress is not known. The present study aimed to analyze the association of arginase I with oxidative stress in a larger healthy population by a newly established ELISA. Design and methods: The new ELISA for the measurement of human arginase I was established by generating recombinant arginase I protein in human arginase I gene-transfected Escherichia coli via an ARG1 cDNA fragment-inserted vector and -specific antibody in rabbits. Serum arginase I was evaluated in a cross-sectional study on a healthy population (n. = 721) by comparing a commercial ELISA kit with the new ELISA. Results: The mean levels of serum arginase I were 20.3. ±. 0.7. ng/mL and 4.7. ±. 0.2. ng/mL using the commercial ELISA kit and the new ELISA, respectively. Arginase I was correlated with WBC, RBC, hs-CRP, 8-OHdG, HDL-c, ALT, and BMI. Logistic regression analysis showed independent positive associations of arginase I with WBC, RBC, and urinary 8-OHdG and inverse independent associations with serum insulin and age. The association of arginase I with hs-CRP was not independent. Conclusion: The independent associations of arginase I with urinary 8-OHdG and serum insulin may reflect its involvement in oxidative stress and diabetes mellitus.