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Recent studies have shown that both glomerular and tubulointerstitial damage are important factors in the pathophysiology and progression of diabetic nephropathy. To examine whether markers of tubular damage are useful in monitoring the progression of disease, we measured urinary levels of neutrophil gelatinase-associated lipocalin (NGAL), liver-fatty acid-binding protein (LFABP), and kidney injury molecule-1 (KIM-1) in a 3-year intervention study of 63 type 1 diabetic patients with kidney disease. The baseline mean glomerular filtration rate (GFR) was 87 ml/min per 1.73 m2 and urinary albumin excretion 1141 mg/24 h. Patients with the highest compared with the lowest quartile of urinary NGAL at baseline had higher urinary KIM-1 levels and a significant decrease in their GFR each year. Using linear regression analysis, we found that elevated urinary NGAL and KIM-1 concentrations were associated with a faster decline in GFR, but not after adjustment for known promoters of progression. Urinary LFABP was not related to decline in GFR. Losartan treatment (100 mg/day) reduced urinary KIM-1 by 43% over a 12-month period. Thus, urine biomarker measurements in patients with type 1 diabetic nephropathy did not provide additional prognostic information to that of known progression promoters. [ABSTRACT FROM AUTHOR]

Renoprotection with and without blood pressure reduction. AT1-receptor blockade dose dependently lowers blood pressure (BP) and albuminuria. Reduction of BP and albuminuria are independent treatment targets for renoprotection, but whether this requires similar dose titration is unknown. We tested this in two studies designed to find the optimal antialbuminuric dose of losartan in type 1 diabetic (DM, N = 50) and nondiabetic renal patients (ND, N = 12). After baseline, treatment followed with losartan 50, 100, and 150 mg/day, each dose for eight (DM) or six weeks (ND). At the end of each period, albuminuria (24-hour samples) and mean arterial pressure (MAP) were measured. Patients were divided into "good" and "poor" BP responders (BP+, BP-) according to BP response above or below group median. Baseline MAP in the BP- groups was 102 (97, 104) mm Hg in DM (median, 95% CI) and 91 (80, 108) mm Hg in ND. The top of the dose response for BP (obtained at losartan 100 mg) in the BP- groups was -2 (-4, 3) mm Hg in DM and –1 (-6, 2) mm Hg in ND, versus -15 (-18, -12) mm Hg and -16 (-26, -18) mm Hg in BP+ groups (both P < 0.05). Albuminuria was reduced dose dependently both in BP- and BP+: with 100 mg, the reduction in albuminuria in DM BP- was -32% (-49, 13) versus -45% (-60, -38) in DM BP+ and -45% (-70,-7) versus –25% (-58, -6) in ND BP- and BP+ (all P > 0.05). Moreover, in patients in whom BP fell below the recommended treatment target of 130/80 mm Hg (13 in DM and 10 in ND), albuminuria was progressively reduced, with further increasing the dose of losartan in most patients. Absence of BP response to losartan does not preclude a reduction in albuminuria, and optimal reduction of albuminuria may require titration beyond the predefined BP target. [ABSTRACT FROM AUTHOR]