Search

Background: Individual patients show a large variability in albuminuria response to angiotensin receptor blockers (ARB). Identifying novel biomarkers that predict ARB response may help tailor therapy. We aimed to discover and validate a serum metabolite classifier that predicts albuminuria response to ARBs in patients with diabetes mellitus and micro- or macroalbuminuria.Methods: Liquid chromatography-tandem mass spectrometry metabolomics was performed on serum samples. Data from patients with type 2 diabetes and microalbuminuria (n = 49) treated with irbesartan 300 mg/day were used for discovery. LASSO and ridge regression were performed to develop the classifier. Improvement in albuminuria response prediction was assessed by calculating differences in R(2) between a reference model of clinical parameters and a model with clinical parameters and the classifier. The classifier was externally validated in patients with type 1 diabetes and macroalbuminuria (n = 50) treated with losartan 100 mg/day. Molecular process analysis was performed to link metabolites to molecular mechanisms contributing to ARB response.Results: In discovery, median change in urinary albumin excretion (UAE) was -42 % [Q1-Q3: -69 to -8]. The classifier, consisting of 21 metabolites, was significantly associated with UAE response to irbesartan (p < 0.001) and improved prediction of UAE response on top of the clinical reference model (R(2) increase from 0.10 to 0.70; p < 0.001). In external validation, median change in UAE was -43 % [Q1-Q35: -63 to -23]. The classifier improved prediction of UAE response to losartan (R(2) increase from 0.20 to 0.59; p < 0.001). Specifically ADMA impacting eNOS activity appears to be a relevant factor in ARB response.Conclusions: A serum metabolite classifier was discovered and externally validated to significantly improve prediction of albuminuria response to ARBs in diabetes mellitus. [ABSTRACT FROM AUTHOR]

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]

OBJECTIVE -- Levels of connective tissue growth factor (CTGF; CCN-2) in plasma are increased in various fibrotic disorders, including diabetic nephropathy. Recently, several articles have reported a strong increase of urinary CTGF excretion (U-CTGF) in patients with diabetic nephropathy. However, these studies addressed too small a number of patients to allow general conclusions to be drawn. Therefore, we evaluated U-CTGF in a large cross-sectional study of patients with type 1 diabetes. RESEARCH DESIGN AND METHODS -- Subjects were 318 type 1 diabetic patients and 29 normoglycemic control subjects. U-CTGF was measured by sandwich enzyme-linked immunosorbent assay. Groups were compared by Kruskal-Wallis and Mann-Whitney analysis. The relation between U-CTGF and markers of diabetic nephropathy was determined by regression analysis. RESULTS -- U-CTGF in patients with diabetic nephropathy (n = 89, median 155 pmol/24 h [interquartile range 96-258]) was significantly higher than in microalbuminuric (n = 79, 100 [65-78]) and normoalbuminuric (n = 150, 85 [48-1271) patients and control subjects (n = 29, 100 [78-1141). U-CTGF correlated with urinary albumin excretion (UAE) (R = 0.31) and glomerular filtration rate (R = -0.38) in patients with diabetic nephropathy. A standardized increase in U-CTGF was associated with diabetic nephropathy (odds ratio 2.3 [95% CI 1.7-3.1]), which was comparable with the odds ratios for diabetic nephropathy of increased HbA[sub 1c] (2.0 [1.5-2.7]), and blood pressure (2.0 [1.5-2.61). CONCLUSIONS -- This is the first large cross-sectional study addressing U-CTGF in human type 1 diabetes. The observed association of U-CTGF with UAE and glomerular filtration rate might reflect a role of CTGF as progression promoter in diabetic nephropathy. [ABSTRACT FROM AUTHOR]

Reduction of urinary connective tissue growth factor by Losartan in type 1 patients with diabetic nephropathy.Background.Connective tissue growth factor (CTGF) is an important profibrotic cytokine implicated in development of diabetic glomerulosclerosis. Urinary CTGF is reported to be significantly increased in patients with diabetic nephropathy. The present study aimed to investigate the short- and long term effects of angiotensin II receptor blockade by Losartan on urinary CTGF levels in hypertensive type 1 diabetic patients with diabetic nephropathy.Methods.Seventy-one hypertensive type 1 diabetic patients with diabetic nephropathy were included in the study. After a washout period of 4 weeks, the patients received Losartan 50 mg, 100 mg, and 150 mg once daily in treatment periods each lasting 2 months. Thereafter, patients were followed prospectively during treatment with Losartan 100 mg o.d. with a total mean follow-up time of 36 months. At baseline, after 2, 4, and 6 months and then biannually, urinary and plasma CTGF levels[enzyme linked immunosorbent assay (ELISA) fibroGen], albuminuria (Turbidimetry), glomerular filtration rate (GFR)[51-creatinine ethylenediaminetetraacetic acid (51Cr-EDTA plasma clearance)] and 24 hours blood pressure (TM2420)) were determined.Results.Baseline levels of urinary and plasma CTGF were 7076 (5708 to 8770) ng/24 hours[geometric mean (95% CI)] and 12.7 (7.3) ng/mL[mean (SD)], respectively. Albuminuria, GFR, and arterial blood pressure at baseline were 1152 (937 to 1416) mg/24 hours, 88 (24) mL/min/1.73 m2, and 153/80 (17/9) mm Hg, respectively. Losartan significantly reduced urinary CTGF by 21% (9 to 31) (95% CI) initially (P<0.05 vs. baseline), with no further reduction after increasing dose. The sustained reduction in urinary CTGF was 22% (12 to 32) (P<0.05 vs. baseline). Rate of decline in GFR during the study was 3.2 (−1.6 to 15.9) mL/min/year[median (range)]. Reduction in urinary CTGF was correlated with a lower rate of decline in GFR (r= 0.23,P= 0.05). Plasma CTGF remained unchanged throughout the study.Conclusion.Our 3-year study demonstrates that Losartan persistently reduces urinary CTGF excretion, which is associated with a slower rate of decline in GFR. [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]

OBJECTIVE -- Irbesartan was renoprotective independently of its blood pressure-lowering effect in the Irbesartan in Patients With Type 2 Diabetes and Microalbuminuria (IRMA2) study. However, blood pressure was evaluated by trough office blood pressure (OBP), which may underestimate reductions in 24-h ambulatory blood pressure (ABP). In the present study, we evaluated 24-h blood pressure patterns in a subpopulation of the IRMA2 trial. RESEARCH DESIGN AND METHODS -- Type 2 diabetic patients (n = 43) with persistent microalbuminuria (as determined by repeated overnight measurements of urinary albumin excretion [UAE]) and hypertension who were included in the IRMA2 study at the Steno Diabetes Center were subjected to 24-h ABP (Takeda, TM2420) measurements before and 2 years after randomization to placebo (n = 15), irbesartan 150 mg daily (Irb150; n = 13), or irbesartan 300 mg daily (Irb300; n = 15). RESULTS -- At baseline, the placebo, Irb150, and Irb300 groups were comparable: OBP: 157 ± 15/89 ± 7, 156 ± 15/91 = 11, and 159 ± 16/90 ± 9 mmHg (NS); 24-h ABP: 148 ± 13/83 ± 11, 148 ± 16/82 ± 7 and 147 ± 16/81 ± 10 mmHg (NS); and UAE (geometric mean with 95% CI): 43 (32-57), 46 (30-70), and 59 (42-85) µg/min (NS), respectively. We found that 2 years after randomization, OBP was significantly reduced in all three groups (by 11/7, 13/8, and 13/8 mmHg in the placebo, Irb150, and Irb300 groups, respectively), but that there were no significant differences among groups. Reductions in 24-h ABP were similar in the three groups (11/10, 5/7, and 7/8 mmHg, respectively; NS), as were reductions in day ABP (11/9, 7/7, and 8/9 mmHg, respectively; NS) and night ABP (4/11, 7/7, and 3/3 mmHg, respectively; NS). The reduction in UAE at the end of the study was 0% (-86 to 42), 38% (- 14 to 66), and 73% (59 to 82), respectively (overall, P < 0.01). CONCLUSION -- Irbesartan is renoprotective independently of its beneficial effect in lowering 24-h blood pressure in patients with type 2 diabetes and persistent microalbuminuria. [ABSTRACT FROM AUTHOR]

Background. Angiotensin II subtype‐1 receptor antagonists represent a valuable new class of drugs in the treatment of diabetic nephropathy. The aim of our study was to evaluate the optimal dose of losartan for renoprotection and blood pressure reduction in diabetic nephropathy. [ABSTRACT FROM PUBLISHER]

Renoprotective effects of losartan in diabetic nephropathy: Interaction with ACE insertion/deletion genotype? Background. The beneficial short- and long-term renoprotective effects of angiotensin I-converting enzyme (ACE) inhibition are lower in albuminuric diabetic patients homozygous for the deletion compared to the insertion polymorphism of the ACE gene. In an attempt to overcome this interaction, we evaluated the short-term renoprotective effect in diabetic nephropathy of the angiotensin II receptor antagonist losartan in patients homozygous for the insertion or the deletion allele. Methods. Fifty-four hypertensive type 1 diabetic patients with diabetic nephropathy homozygous for the insertion (I; N = 26) or the deletion (D; N = 28) allele of the ACE/ID polymorphism were included. After four weeks of washout, the patients received losartan 50 mg daily followed by 100 mg in two treatment periods each lasting two months. Patients and investigators were blinded to ACE genotypes. At baseline and in the end of the treatment periods, 24-hour blood pressure, albuminuria and glomerular filtration rate values were determined. Results. At baseline, blood pressure, albuminuria and glomerular filtration rate (GFR) values were similar in the two genotype groups [II vs. DD, 1134 (238 to 5302) vs. 1451 (227 to 8129) mg/24 h, median (range); 156/82 (17/9) vs. 153/80 (17/11) mm Hg, mean (SD); and 86 (22) vs. 88 (24) mL/min/1.73 m2 , respectively]. Both doses of losartan significantly lowered blood pressure, albuminuria, and GFR (P < 0.05 vs. baseline). Losartan 100 mg was more effective than 50 mg in reducing albuminuria, 51% (95% CI; 40 to 61) versus 33% (23 to 42), respectively (P < 0.01). No differences in the impact of losartan between the II and DD groups were observed: Losartan 100 mg lowered systolic/diastolic blood pressure by 12/6 and 10/4 mm Hg, whereas albuminuria decreased by 55% (35 to 68) and 46% (28 to 61), in the II and DD groups, respectively (P =... [ABSTRACT FROM AUTHOR]