N-003 HIGH L-CITRULLINE TO L-ARGININE RATIO RELATES TO BLOOD PRESSURE ABNORMALITIS IN CHILDREN WITH CHRONIC KIDNEY DISEASE

Abstract

Background Cardiovascular disease is a major cause of death in children with chronic kidney disease (CKD). The 24-hr ambulatory blood pressure monitoring (ABPM) is a superior predictor of cardiovascular outcome when compared to clinic BP measurement. In the kidney, L-citrulline (Cit) can be converted to L-arginine (Arg) to generate NO. We found that restoration of renal Arg availability is associated with lowering BP in young SHR. Thus we hypothesize that plasma Cit-to-Arg ratio reflects renal Arg availability, which relates to BP abnormalities in children with early chronic kidney disease (CKD). Methods The CKD staging is defined by the K/DOQI guideline. The eGFR was calculated by the Schwartz formula on the basis of height and serum creatinine. Plasma Arg and Cit levels were measured by HPLC. Subjects wore a 24-hr ABPM. Results We totally enrolled 22 children with stages 1–2 CKD. Approximately 80% (18/22) of children with early CKD had BP abnormalities. We found plasma levels of Cit and Arg, and Cit-to-Arg ratio were not different between children with CKD 1 (n = 8) and those with CKD 2 (n = 14). However, plasma Cit level and Cit-to-Arg ratio both were significantly higher in patients with abnormal ABPM profile than those with normal profile, including BP load and nocturnal BP-dipping. In addition, we found that plasma Cit level showed a significantly positive correlation with nighttime systolic (r = 0.464, P = 0.029) and diastolic BP (r = 0.479, P = 0.024), and diastolic BP load (r = 0.608, P = 0.003). Similarly, plasma Cit-to-Arg ratio was positively correlated with nighttime systolic (r = 0.52, P = 0.013) and diastolic BP (r = 0.564, P = 0.006), and diastolic BP load (r = 0.704, P < 0.001). Conclusions In conclusion, high Cit level and Cit-to-Arg ratio in the plasma are associated with BP abnormalitis on ABPM in children with CKD. Plasma Cit-to-Arg ratio may serve as a marker of cardiovascular outcome in children and adolescents with early CKD.