Modulation of advanced glycation end products by candesartan in patients with diabetic kidney disease--a dose-response relationship study.

Advanced glycation end products (AGEs) are proinflammatory mediators implicated in the pathogenesis of diabetic kidney disease (DKD). In this study, dose-dependent effects of angiotensin receptor blockade on urinary AGEs were evaluated in patients with DKD. Patients with type 2 diabetes and proteinuria ≥500 mg/d (n = 11) were compared with diabetic controls without DKD (n = 10) and normal controls (n = 11). After a 2-week washout period, DKD participants were treated with candesartan doses progressively increasing from 8, 16, 32, to 64 mg/d every 3 weeks for a total of 12 weeks. Other antihypertensive agents were adjusted to maintain stable blood pressure. At baseline and after each dosing period, blood pressure measurements and 24-hour urine collections were obtained. Urinary carboxymethyl lysine, an AGE biomarker, was reduced over the 12-week dose escalation protocol (r = 0.38, P = 0.01) in DKD participants. Creatinine clearance increased slightly, but albuminuria was unaffected by candesartan administration. Baseline urinary transforming growth factor-β₁ excretion was lower in DKD participants than in controls and did not change during the study period. Reducing kidney exposure to AGEs may be a mechanism of protection by angiotensin receptor blockade in DKD. AGEs may also impact the diabetic kidney through mechanisms independent of transforming growth factor-β₁.