RNA interference targeting the ACE gene reduced blood pressure and improved myocardial remodelling in SHRs

2009 ◽  
Vol 116 (3) ◽  
pp. 249-255 ◽  
Author(s):  
Junhua He ◽  
Yunfei Bian ◽  
Fen Gao ◽  
Maolian Li ◽  
Ling Qiu ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Body Weight ◽  
Rna Interference ◽  
Serum Concentration ◽  
Systolic Blood Pressure ◽  
Normal Saline ◽  
Left Ventricular ◽  
Heart Weight ◽  
Wky Rats ◽  
Wistar Kyoto

The purpose of the present study was to investigate the effects on blood pressure and myocardial hypertrophy in SHRs (spontaneously hypertensive rats) of RNAi (RNA interference) targeting ACE (angiotensin-converting enzyme). SHRs were treated with normal saline as vehicle controls, with Ad5-EGFP as vector controls, and with recombinant adenoviral vectors Ad5-EGFP-ACE-shRNA, carrying shRNA (small hairpin RNA) for ACE as ACE-RNAi. WKY (Wistar–Kyoto) rats were used as normotensive controls treated with normal saline. The systolic blood pressure of the caudal artery was recorded. Serum levels of ACE and AngII (angiotensin II) were determined using ELISA. ACE mRNA and protein levels were determined in aorta, myocardium, kidney and lung. On day 32 of the experiment, the heart was pathologically examined. The ratios of heart weight/body weight and left ventricular weight/body weight were calculated. The serum concentration of ACE was lower in ACE-RNAi rats (16.37±3.90 ng/ml) compared with vehicle controls and vector controls (48.26±1.50 ng/ml and 46.67±2.82 ng/ml respectively; both P<0.05), but comparable between ACE-RNAi rats and WKY rats (14.88±3.15 ng/ml; P>0.05). The serum concentration of AngII was also significantly lower in ACE-RNAi rats (18.24±3.69 pg/ml) compared with vehicle controls and vector controls (46.21±5.06 pg/ml and 44.93±4.12 pg/ml respectively; both P<0.05), but comparable between ACE-RNAi rats and WKY rats (16.06±3.11 pg/ml; P>0.05). The expression of ACE mRNA and ACE protein were significantly reduced in the myocardium, aorta, kidney and lung in ACE-RNAi rats compared with that in vehicle controls and in vector controls (all P<0.05). ACE-RNAi treatment resulted in a reduction in systolic blood pressure by 22±3 mmHg and the ACE-RNAi-induced reduction lasted for more than 14 days. In contrast, blood pressure was continuously increased in the vehicle controls as well as in the vector controls. The ratios of heart weight/body weight and left ventricular weight/body weight were significantly lower in ACE-RNAi rats (3.12±0.23 mg/g and 2.24±0.19 mg/g) compared with the vehicle controls (4.29±0.24 mg/g and 3.21±0.13 mg/g; P<0.05) and the vector controls (4.43±0.19 mg/g and 3.13±0.12 mg/g; P<0.05). The conclusion of the present study is that ACE-silencing had significant antihypertensive effects and reversed hypertensive-induced cardiac hypertrophy in SHRs, and therefore RNAi might be a new strategy in controlling hypertension.

Characterization of myocardium, isolated cardiomyocytes, and blood pressure in WKHA and WKY rats

2002 ◽  
Vol 282 (1) ◽  
pp. H149-H155 ◽  
Author(s):  
Christian F. Deschepper ◽  
Sylvie Picard ◽  
Gaétan Thibault ◽  
Rhian Touyz ◽  
Jean-Lucien Rouleau
Keyword(s):  
Blood Pressure ◽  
Diastolic Blood Pressure ◽  
Left Ventricular ◽  
Free Calcium ◽  
Isolated Cardiomyocytes ◽  
Cell Width ◽  
Cross Sectional ◽  
Wky Rats ◽  
Ventricular Cardiomyocytes ◽  
Wistar Kyoto

We previously reported that the left ventricular (LV) mass of Wistar-Kyoto (WKY)-derived hyperactive (WKHA) rats was higher than that of WKY rats in the absence of a difference in systolic blood pressure. To extend these earlier observations, we conducted a series of functional and morphological investigations on both strains. Analysis of tissue sections revealed that the surface of ventricular tissue from WKHA rats was higher than that of WKY rats, without any enlargement of the cavity area. Analysis of isolated adult cells showed that cell width (as well as cell volume) of ventricular cardiomyocytes was significantly higher in WKHA than WKY rats. However, LV of WKHA rats contained ∼33% less cardiomyocytes than those from WKY rats. Mean intracellular free calcium concentration of cardiomyocytes was also higher in WKHA than WKY rats. Hemodynamic measurements revealed that the values of the maximum rates of pressure change (dP/d t) were higher in LV from WKHA rats. However, these differences were reduced (−dP/d t) or abolished (+dP/d t) when the values were normalized for both the number and mean cross-sectional area of ventricular cardiomyocytes. Mean levels of systolic and diastolic blood pressure (corresponding to the 24-h average of measurements obtained continuously in conscious unrestrained animals using radiotelemetric implants) were not different between strains. However, circadian rhythm was more evident in WKY rats, because the difference between morning and night values of systolic and diastolic blood pressure was greater (by 3 mmHg) in WKY rats. Altogether, our data validate the use of WKHA rats as models of predominantly concentric LV hypertrophy developing in the absence of increased mean levels of hemodynamic cardiac load and show that the hypertrophy phenotype is more pronounced in isolated cardiomyocytes than at the level of the whole ventricle.

Vasopressin in the rat with spontaneous hypertension

1978 ◽  
Vol 235 (4) ◽  
pp. H361-H366 ◽  
Author(s):  
J. T. Crofton ◽  
L. Share ◽  
R. E. Shade ◽  
C. Allen ◽  
D. Tarnowski
Keyword(s):  
Blood Pressure ◽  
Urinary Excretion ◽  
Systolic Blood Pressure ◽  
Blood Volume ◽  
Rat Plasma ◽  
Wky Rats ◽  
Naturally Occurring ◽  
Plasma Vasopressin ◽  
Wistar Kyoto

Because vasopressin is one of the most potent naturally occurring pressor agents, and because of its importance in the regulation of blood volume and composition, we have undertaken a study of the role of vasopressin in the pathogenesis of the hypertension in the Okamoto-Aoki spontaneously hypertension (SH) rat. In SH rats, systolic blood pressure increased from 135 +/- 3 (SE) mmHg at age 33 days to 184 +/- 3 mmHg at age 75 days (P less than 0.01). In the Wistar-Kyoto (WKY) control rats, blood pressure increased from 100 +/- 2 to 120 +/- 2 mmHg (P less than 0.01). The differences in blood pressure between the SH and WKY rats at all ages were significant (P less than 0.01). During the age period 33-75 days, the 24-h urinary excretion of vasopressin in the SH rat was consistently more than twofold greater (P less than 0.01) than in the WKY rat. Plasma vasopressin concentration and pituitary vasopressin content were also elevated in the SH rat (P less than 0.01 and P less than 0.02, respectively). Changes in systolic blood pressure in the SH rat, however, were not paralleled by changes in the urinary excretion of vasopressin. The data indicate that the secretion of vasopressin is elevated in the SH rat. However, the magnitude of this elevation, in and of itself, may not be sufficient to account for the rising blood pressure in the young SH rat.

Characterization of blood pressure and morphological traits in cardiovascular-related organs in 13 different inbred mouse strains

2004 ◽  
Vol 97 (1) ◽  
pp. 369-376 ◽  
Author(s):  
Christian F. Deschepper ◽  
Jean L. Olson ◽  
Melissa Otis ◽  
Nicole Gallo-Payet
Keyword(s):  
Blood Pressure ◽  
Body Weight ◽  
Systolic Blood Pressure ◽  
Quantitative Traits ◽  
Inbred Mouse ◽  
Left Ventricular ◽  
Mouse Strains ◽  
Genome Database ◽  
Male And Female ◽  
Mouse Phenome Database

To better understand the contributions of various genetic backgrounds to complex quantitative phenotypes, we have measured several quantitative traits of cardiovascular interest [i.e., systolic blood pressure, weight (corrected by body weight) of several cardiac compartments and adrenals and kidneys, and histological correlates for kidneys and adrenals] in male and female mice from 13 different inbred strains. We selected strains so that each major genealogical group would be represented and to conform to priorities set by the Mouse Phenome Database project. Interstrain comparisons of phenotypes made it possible to identify strains that displayed values that belonged to either the low or the high end of the interstrain variance for quantitative traits, such as systolic blood pressure, body weight, left ventricular weight, and/or adrenocortical structure. For instance, both male and female C3H/HeJ and A/J mice displayed either low systolic blood pressure or low cardiac ventricular mass, respectively, and male C57BL6/J displayed low adrenal weight. Likewise, intersex comparisons made it possible to identify phenotypic values that were sexually dimorphic for some of the same traits. For instance, female AKR/J mice had relatively higher body weight and systolic blood pressure values than their male counterparts, perhaps constituting an animal model of the metabolic X syndrome. These strain- and sex-specific features will be of value both for future genetic and/or developmental studies and for the development of new animal models that will help in the generation of mechanistic hypotheses. All data have been deposited to the Mouse Phenome Database for future integration with the Mouse Genome Database and can be further analyzed and compared with tools available on the site.

Reversibility of cold-induced hypertension after removal of rats from cold

1990 ◽  
Vol 68 (7) ◽  
pp. 830-835 ◽  
Author(s):  
Orit Shechtman ◽  
Paula E. Papanek ◽  
Melvin J. Fregly
Keyword(s):  
Blood Pressure ◽  
Body Weight ◽  
Cardiac Hypertrophy ◽  
Cold Exposure ◽  
Adrenal Glands ◽  
Treated Group ◽  
Left Ventricular ◽  
Male Rats ◽  
Heart Weight ◽  
Renal Hypertrophy

Chronic exposure of rats to cold air induces hypertension, including elevation of blood pressure and cardiac hypertrophy. The present study was designed to assess reversibility of these changes after removal from cold. Five groups of six male rats each were exposed to cold (5 ± 2 °C) for 39 days, while six control rats were maintained at 26 ± 2 °C. Systolic blood pressures of the rats in one of the cold-treated groups, as well as the controls, were measured twice weekly throughout the experiment. Blood pressure of the cold-exposed rats (150 ± 3 mmHg; 1 mmHg = 133.3 Pa) became elevated significantly above that of controls (129 ± 3 mmHg) within 4 weeks. On day 39 of cold exposure, one group (six rats) of the cold-treated rats was sacrificed while still in the cold. The remaining four groups of cold-treated rats were than removed from cold and kept at 26 ± 2 °C. One group of cold-treated rats was sacrificed weekly thereafter. During the last week, the six control rats were also sacrificed. At death, the heart, kidneys, and adrenal glands were removed and weighed. Mean heart weight of the cold-treated group (346 ± 7 mg/100 g body weight), sacrificed prior to removal from cold, was significantly (p < 0.01) greater than that of controls (268 ± 5 mg/100 g body weight). The increased heart weight of the cold-treated group appeared to result mainly from an increase in left ventricular weight. The weights (mg/100 g body weight) of the kidneys and adrenal glands of cold-treated rats, measured prior to removal from cold, were significantly (p < 0.01) greater than those of controls. Two weeks after removal from cold, blood pressure, heart weight, and left ventricular weight decreased from the levels observed prior to removal from cold. However, they were still significantly greater than those of controls through the fourth week after removal from cold. Thus, the hypertension accompanying a 39-day exposure to cold appears to be only partially reversible at 4 weeks after removal from cold.Key words: cold exposure, hypertension, blood pressure, reversibility of hypertension, renal hypertrophy, cardiac hypertrophy.

Myocardial hypertrophy of normotensive Wistar-Kyoto rats

2004 ◽  
Vol 286 (4) ◽  
pp. H1229-H1235 ◽  
Author(s):  
Ernesto A. Aiello ◽  
María C. Villa-Abrille ◽  
Eduardo M. Escudero ◽  
Enrique L. Portiansky ◽  
Néstor G. Pérez ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Cardiac Hypertrophy ◽  
Wistar Rats ◽  
Left Ventricular ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Wky Rats ◽  
Wistar Kyoto ◽  
Cell Capacitance

In our studies with spontaneously hypertensive (SHR), Wistar-Kyoto (WKY), and Wistar rats, we observed normotensive WKY rats with cardiac hypertrophy determined by a greater left ventricular (LV) mass (LVM)-to-body weight (BW) ratio (LVM/BW) than that of normotensive Wistar rats. Thus we compared the following parameters in SHR, WKY, and Wistar rats: LVM/BW, cell capacitance as index of total surface area of the myocytes, length, width, and cross-sectional area of cardiac myocytes, LV collagen volume fraction, and myocardial stiffness. The LVM/BW of WKY (2.41 ± 0.03 mg/g, n = 41) was intermediate between SHR (2.82 ± 0.04 mg/g, n = 47) and Wistar rats (1.98 ± 0.04 mg/g, n = 28). A positive correlation between blood pressure and LVM was found in SHR, whereas no such relationship was observed in WKY or Wistar rats. Cell capacitance and cross-sectional area were not significantly different in SHR and WKY rats; these values were significantly higher than those of Wistar rats. The cell length was smaller but the width was similar in WKY compared with SHR. Papillary muscles isolated from the LV of WKY and SHR were stiffer than those from Wistar rats. Consistently, a greater level of myocardial fibrosis was detected in WKY and SHR compared with Wistar rats. These findings demonstrate blood pressure-independent cardiac hypertrophy in normotensive WKY rats.

Altered cardiac polyamine biosynthesis in spontaneously hypertensive rats

1987 ◽  
Vol 253 (2) ◽  
pp. H262-H269 ◽  
Author(s):  
H. Ruskoaho ◽  
H. Raunio
Keyword(s):  
Ventricular Hypertrophy ◽  
Left Ventricular ◽  
Heart Weight ◽  
Polyamine Biosynthesis ◽  
Spontaneously Hypertensive ◽  
Wky Rats ◽  
Developing Heart ◽  
Polyamine Content ◽  
Old Rats ◽  
Wistar Kyoto

To evaluate the role of polyamine biosynthesis in myocardial growth, the activity of ornithine decarboxylase (ODC) and the levels of the polyamines, spermidine, spermine, and putrescine, were measured in the hearts of spontaneously hypertensive (SHR) and Wistar-Kyoto (WKY) rats between birth and 30 wk of age and in 30-wk-old rats after 6 wk treatment with either minoxidil (0.08 mg/ml) or methyldopa (5 mg/ml drinking water). ODC activity was initially high in the developing heart (150 pmol X mg protein-1 X 30 min-1) and decreased with age. In the SHR after 4 wk of age, spermidine content was consistently raised in both ventricles compared with the WKY rats. Spermine was reduced in the left ventricle of the SHR, resulting in high spermidine-to-spermine ratios characteristic of rapidly growing systems. Ventricular ODC activity and putrescine levels were also slightly but less consistently elevated in the ventricles of the SHR compared with respective WKY rats. Minoxidil treatment increased heart weight and left ventricular spermidine and spermine content in both SHR and WKY rats. Methyldopa also caused a significant increase in left ventricular spermidine content despite a marked reduction in ventricular mass. Thus ventricular hypertrophy in SHR is accompanied by an enhanced synthesis and accumulation of spermidine. The fact that myocardial spermidine content increased during methyldopa treatment, which reduced the myocardial mass, suggests that regression of ventricular hypertrophy can occur independently of changes in polyamine content.

scholarly journals Blood pressure reduction after gastric bypass surgery is explained by a decrease in cardiac output

2017 ◽  
Vol 122 (2) ◽  
pp. 223-229 ◽  
Author(s):  
Peter M. van Brussel ◽  
Bas van den Bogaard ◽  
Barbara A. de Weijer ◽  
Jasper Truijen ◽  
C.T. Paul Krediet ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Gastric Bypass ◽  
Body Weight ◽  
Cardiac Output ◽  
Baroreflex Sensitivity ◽  
Bypass Surgery ◽  
Gastric Bypass Surgery ◽  
Left Ventricular ◽  
Ventricular Contractility ◽  
Left Ventricular Contractility

Blood pressure (BP) decreases in the first weeks after Roux-and-Y gastric bypass surgery. Yet the pathophysiology of the BP-lowering effects observed after gastric bypass surgery is incompletely understood. We evaluated BP, systemic hemodynamics, and baroreflex sensitivity in 15 obese women[mean age 42 ± 7 standard deviation (SD) yr, body mass index 45 ± 6 kg/m2] 2 wk before and 6 wk following Roux-and-Y gastric bypass surgery. Six weeks after gastric bypass surgery, mean body weight decreased by 13 ± 5 kg (10%, P < 0.001). Office BP decreased from 137 ± 10/86 ± 6 to 128 ± 12/81 ± 9 mmHg ( P < 0.001, P < 0.01), while daytime ambulatory BP decreased from 128 ± 14/80 ± 9 to 114 ± 10/73 ± 6 mmHg ( P = 0.01, P = 0.05), whereas nighttime BP decreased from 111 ± 13/66 ± 7 to 102 ± 9/62 ± 7 mmHg ( P = 0.04, P < 0.01). The decrease in BP was associated with a 1.6 ± 1.2 l/min (20%, P < 0.01) decrease in cardiac output (CO), while systemic vascular resistance increased (153 ± 189 dyn·s·cm−5, 15%, P < 0.01). The maximal ascending slope in systolic blood pressure decreased (192 mmHg/s, 19%, P = 0.01), suggesting a reduction in left ventricular contractility. Baroreflex sensitivity increased from 9.0 [6.4–14.3] to 13.8 [8.5–19.0] ms/mmHg (median [interquartile range]; P < 0.01) and was inversely correlated with the reductions in heart rate ( R = −0.64, P = 0.02) and CO ( R = −0.61, P = 0.03). In contrast, changes in body weight were not correlated with changes in either BP or CO. The BP reduction following Roux-and-Y gastric bypass surgery is correlated with a decrease in CO independent of changes in body weight. The contribution of heart rate to the reduction in CO together with enhanced baroreflex sensitivity suggests a shift toward increased parasympathetic cardiovascular control. NEW & NOTEWORTHY The reason for the decrease in blood pressure (BP) in the first weeks after gastric bypass surgery remains to be elucidated. We show that the reduction in BP following surgery is caused by a decrease in cardiac output. In addition, the maximal ascending slope in systolic blood pressure decreased suggesting a reduction in left ventricular contractility and cardiac workload. These findings help to understand the physiological changes following gastric bypass surgery and are relevant in light of the increased risk of heart failure in these patients.

scholarly journals Effect of Age and Body Weight on the Systolic Blood Pressure of the Growing Chicken

1963 ◽  
Vol 42 (6) ◽  
pp. 1465-1466 ◽  
Author(s):  
E.L. Nichols ◽  
D.K. Hotchkiss ◽  
S.L. Balloun
Keyword(s):  
Blood Pressure ◽  
Body Weight ◽  
Systolic Blood Pressure ◽  
Effect Of Age

Metformin decreases plasma insulin levels and systolic blood pressure in spontaneously hypertensive rats

1994 ◽  
Vol 267 (4) ◽  
pp. H1250-H1253 ◽  
Author(s):  
S. Verma ◽  
S. Bhanot ◽  
J. H. McNeill
Keyword(s):  
Blood Pressure ◽  
Systolic Blood Pressure ◽  
Spontaneously Hypertensive Rats ◽  
Plasma Insulin ◽  
Metformin Treatment ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Insulin Levels ◽  
Plasma Insulin Levels ◽  
Wistar Kyoto

To determine the relationship between hyperinsulinemia and hypertension in spontaneously hypertensive rats (SHR), the antihyperglycemic agent metformin was administered to SHR and their Wistar-Kyoto (WKY) controls, and its effects on plasma insulin levels and blood pressure were examined. Five-week-old rats were started on oral metformin treatment (350 mg.kg-1.day-1, which was gradually increased to 500 mg.kg-1.day-1 over a 2-wk period). Metformin treatment caused sustained decreases in plasma insulin levels in the SHR (27.1 +/- 2.3 vs. untreated SHR 53.5 +/- 2.7 microU/ml, P < 0.001) without having any effect in the WKY (30.7 +/- 2.2 vs. untreated WKY 37.8 +/- 1.6 microU/ml, P > 0.05). The treatment did not affect the plasma glucose levels in any group. Metformin treatment also attenuated the increase in systolic blood pressure in the SHR (157 +/- 6.0 vs. untreated SHR 196 +/- 9.0 mmHg, P < 0.001) but had no effect in the WKY (134 +/- 3 vs. untreated WKY 136 +/- 4 mmHg, P > 0.05). Furthermore, raising plasma insulin levels in the metformin-treated SHR to levels that existed in the untreated SHR reversed the effect of metformin on blood pressure (189 +/- 3 vs. untreated SHR 208 +/- 5.0 mmHg, P > 0.05). These findings suggest that either hyperinsulinemia may contribute toward the increase in blood pressure in the SHR or that the underlying mechanism is closely associated with the expression of both these disorders.

Sign in / Sign up

Export Citation Format

Share Document