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High salt intake induces left ventricular interstitial fibrosis by a blood pressure and angiotensin II type 1 receptor‐independent mechanism
Author(s) -
Ferreira Daniele Nunes,
Katayama Isis A.,
Oliveira Ivone B.,
Rosa Kaleizu T.,
Coelho Michella S.,
Heimann Joel C.
Publication year - 2009
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.23.1_supplement.626.9
Subject(s) - losartan , medicine , angiotensin ii , endocrinology , pressure overload , receptor , blood pressure , chemistry , muscle hypertrophy , angiotensin ii receptor type 1 , left ventricular hypertrophy , cardiology , cardiac hypertrophy
Objective To evaluate the mechanisms of left (LV) and right (RV) ventricular hypertrophy induced by salt overload. Methods 18‐week‐old Wistar rats were fed normal (NS: 1.3% NaCl), high 1 (HS1 4%) or high 2 (HS2 8%) salt diet since weaning. Starting on the 7 th week of age, two HS2 subgroups received hydralazine or losartan (HZ 15 and LOS 20 mg/kg/day). Tail cuff blood pressure (BP), myocyte transverse diameter (TD), interstitial fibrosis (IF) and angiotensin II type 1 (AT 1 ) receptor and collagen type I (COL 1) protein expression were measured. Results (mean±SEM ‐ p<0.05, n=7‐8/group) At 18 th week of age, BP (mmHg) was higher on HS1 (146±2) and HS2 (147±1) than on NS (121±2). BP on HS2+HZ (123±1) and HS2+LOS (120±2) did not differ from NS. TD in the LV was higher on HS1 (14±0.2), HS2 (16±0.5) and HS2+HZ (15±0.2) than on NS (12±0.4) and HS2+LOS (12±0.1). TD in the RV was higher on HS2 (15±0.5) and HS2+HZ (15±0.5) than on NS (12±0.3), HS1 (13±0.5) and HS2+LOS (11±0.1). IF and COL 1 (AU) in the LV and RV were higher on HS1, HS2 and HS2+LOS than on NS and HS2+HZ (COL 1 LV: HS1 1.04±0.05, HS2 1.10±0.01, HS2+HZ 0.91±0.04, HS2+LOS 1.02±0.02 and NS 0.87±0.02). AT 1 (AU) in the LV and RV was higher on HS2, HS2+HZ than NS, HS1 and HS2+LOS (AT 1 LV: HS2 1.1±0.02, HS2+HZ 1.1±0.01, HS2+LOS 0.9±0.02 and NS 0.9±0.08). Conclusions HS leads to LV hypertrophy by a BP independent effect. It can be speculated that the effect of HS on TD and IF is due to different mechanisms. FAPESP