Transient prehypertensive treatment in spontaneously hypertensive rats: a comparison of losartan and amlodipine regarding long-term blood pressure, cardiac and renal protection.
The aim of this study was to compare the effectiveness of transient prehypertensive treatment with losartan compared with amlodipine in spontaneously hypertensive rats (SHRs) on long-term blood pressure (BP), cardiac and renal protection. SHRs were prehypertensively treated with losartan, amlodipine or saline. Rats were followed up until 46 weeks of age. The left ventricular (LV) geometry and function were assessed by echocardiography. Angiotensin II (Ang II) and aldosterone (Aldo) were measured by radioimmunoassay. Ang II type 1 (AT1R) and type 2 (AT2R) receptor protein expression was determined by western blotting. The systolic blood pressure (SBP) in losartan-treated SHRs (SHR-Los) was persistently reduced until 46 weeks of age, but returned to untreated SHR levels in amlodipine-treated SHRs (SHR-Aml) from 30 weeks onwards. Compared to untreated SHRs, the albuminuria excretion in SHR-Los at week 46 was markedly decreased, the plasma, myocardium and renal tissue Ang II and Aldo levels in SHR-Los at week 46 were markedly decreased; AT1R and TGF-β1 protein expression was downregulated and AT2R protein was upregulated. Compared to untreated SHRs, the left ventricular mass index (LVMI) and collagen volume fraction (CVF) in SHR-Los were markedly decreased until week 46, and the left ventricular ejection fraction (LVEF) and cardiac brain natriuretic peptide mRNA expression were improved, whereas similar LVMI and elevated CVF were observed in SHR-Aml, and the LVEF decreased significantly below that of untreated SHRs at week 46, with cardiac BNP mRNA expression increasing slightly. Prehypertensive treatment with losartan was more effective than amlodipine on delaying long-term BP increase and ameliorating cardiac, renal structure and function, which may be related to the permanent attenuation of the circulating and local renin-angiotensin systems.
First Clinical Medical College of Fujian Medical University, Fuzhou 350005, P.R. China.
Feng
F
Peng
Jinxiu
J
Lin
Liming
L
Lin
Hong
H
Tang
D000450:Aldosterone / Q000097:blood; D017311:Amlodipine / Q000494:pharmacology* / Q000627:therapeutic use; D000804:Angiotensin II / Q000097:blood; D000818:Animals; D000959:Antihypertensive Agents / Q000494:pharmacology* / Q000627:therapeutic use; D001794:Blood Pressure / Q000187:drug effects; D002316:Cardiotonic Agents / Q000494:pharmacology* / Q000627:therapeutic use; D003094:Collagen / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects; D006352:Heart Ventricles / Q000000981:diagnostic imaging / Q000187:drug effects / Q000503:physiopathology; D006973:Hypertension / Q000097:blood / Q000150:complications / Q000188:drug therapy* / Q000503:physiopathology; D017379:Hypertrophy, Left Ventricular / Q000209:etiology / Q000517:prevention & control; D007668:Kidney / Q000187:drug effects* / Q000473:pathology / Q000503:physiopathology; D019808:Losartan / Q000494:pharmacology* / Q000627:therapeutic use; D008297:Male; D020097:Natriuretic Peptide, Brain / Q000235:genetics / Q000378:metabolism; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D044140:Receptor, Angiotensin, Type 1 / Q000235:genetics / Q000378:metabolism; D044139:Receptor, Angiotensin, Type 2 / Q000235:genetics / Q000378:metabolism; D012084:Renin-Angiotensin System; D013318:Stroke Volume / Q000187:drug effects; D053773:Transforming Growth Factor beta1 / Q000378:metabolism; D014463:Ultrasonography
D000959:Antihypertensive Agents; D002316:Cardiotonic Agents; D044140:Receptor, Angiotensin, Type 1; D044139:Receptor, Angiotensin, Type 2; D053773:Transforming Growth Factor beta1; D000804:Angiotensin II; D020097:Natriuretic Peptide, Brain; D017311:Amlodipine; D000450:Aldosterone; D003094:Collagen; D019808:Losartan