Renal GLUT1 reduction depends on angiotensin-converting enzyme inhibition in diabetic hypertensive rats

Author(s)

da Silva, Ariel S. ^[1] ; Dias, Lucinara D. ^[1] ; Borges, Julia F. ^[1] ; Markoski, Melissa M. ^[1] ; de Souza, Martina S. ^{[1, 2]} ; Irigoyen, Maria C. ^{[1, 3]} ; Machado, Ubiratan F. ^[4] ; Schaan, Beatriz D. ^{[1, 2]}

Affiliation

^[1] Fundacao Univ Cardiol IC FUC, Inst Cardiol Rio Grande Sul, Porto Alegre, RS - Brazil

^[2] Univ Fed Rio Grande Sul UFRGS, Div Endocrine, Hosp Clin Porto Alegre HCPA, Porto Alegre, RS - Brazil

^[3] Univ Sao Paulo, Unidade Hipertensao, Inst Coracao INCOR, Sao Paulo - Brazil

^[4] Univ Sao Paulo, Dept Physiol & Biophys, Inst Ciencia Biomed USP, Sao Paulo - Brazil

• Document type: Journal article
• Source: Life Sciences; v. 92, n. 24-26, p. 1174-1179, JUL 10 2013.
• Web of Science Citations: 2

Abstract

Aims: Angiotensin-converting enzyme (ACE) inhibitors are used in diabetic kidney disease to reduce systemic/intra-glomerular pressure. The objective of this study was to investigate whether reducing blood pressure (BP) could modulate renal glucose transporter expression, and urinary markers of diabetic nephropathy in diabetic hypertensive rats treated with ramipril or amlodipine. Main methods: Diabetes was induced in spontaneously-hypertensive rats (similar to 210 g) by streptozotocin (50 mg/kg). Thirty days later, animals received ramipril 15 mu g/kg/day (R, n = 10), or amlodipine 10 mg/kg/day (A, n = 8,) or water (C, n = 10) by gavage. After 30-day treatment, body weight, glycaemia, urinary albumin and TGF-beta 1 (enzyme-linked immunosorbent assay) and BP (tail-cuff pressure method) were evaluated. Kidneys were removed for evaluation of renal cortex glucose transporters (Western blotting) and renal tissue ACE activity (fluorometric assay). Key findings: After treatments, body weight (p = 0.77) and glycaemia (p = 0.22) were similar among the groups. Systolic BP was similarly reduced (p < 0.001) in A and R vs. C (172.4 +/- 3.2; 186.7 +/- 3.7 and 202.2 +/- 4.3 mm Hg; respectively). ACE activity (C: 0.903 +/- 0.086; A: 0.654 +/- 0.025, and R: 0.389 +/- 0.057 mU/mg), albuminuria (C: 264.8 +/- 15.4; A: 140.8 +/- 13.5 and R: 102.8 +/- 6.7 mg/24 h), and renal cortex GLUM content (C: 46.81 +/- 4.54; A: 40.30 +/- 5.39 and R: 26.89 +/- 0.79 AU) decreased only in R (p < 0.001, p < 0.05 and p < 0.001; respectively). Significance: We concluded that the blockade of the renin-angiotensin system with ramipril reduced early markers of diabetic nephropathy, a phenomenon that cannot be specifically related to decreased BP levels. (C) 2013 Elsevier Inc. All rights reserved. (AU)

• FAPESP's process: 12/04831-1 - New players in glycemic control and chronic complications of Diabetes mellitus: preventive and therapeutic perspectives
• Grantee: Ubiratan Fabres Machado
• Support type: Research Projects - Thematic Grants