INHIBITION OF CARDIAC HYPERTROPHY AND NORMALIZATION OF CARDIAC CONTRACTILE RESPONSE IN EXPERIMENTAL HYPERTENSION. DISPARATE RESULTS IN RATS

GOMEZ-LLAMBI HERNAN; DONATO M; BUCHHOLZ B; OTTAVIANO G; MULLER A; GELPI R; OTERO-LOSADA M; MILEI J

London

Congreso; 22nd. European Meeting on Hypertension and Cardiovascular Protection; 2012

European Society of Hypertension

Objective: To evaluate if chronic antihypertensive treatment inhibits the left ventricular hypertrophy (LVH) and reverses the impairment in cardiac response to beta adrenergic stimulation. Design and Method: Male Spontaneously Hypertensive Rats (SHR), 8 weeks old, were treated with either losartan 30mg/kg (L), hydralazine 11mg/kg (H), rosuvastatin 10 mg/kg (R), (n=18 each group) or carvedilol 20 mg/kg (C), (n=16) per os (tap water) for 16 months. Untreated SHR and Wistar Kyoto (WKY) groups (n=18 each) were included as controls. Systolic blood pressure (SBP) was periodically measured (tail cuff plethysmography). At the end of treatment the animals were weighed (body weight, BW) and euthanasia was practiced under pentobarbital anesthesia. Half of the hearts were mounted in a Langendhorf preparation. Left ventricular end diastolic pressure (LVEDP), developed ventricular pressure (LVDP), the first derivate of developed pressure (DP/DT+), the first derivate of decrement of developed pressure (dp/dt-) and TAU, as a relaxation index, were recorded before and after isoproterenol (ISO) (10-9M,10-7M and 10-5M). The other half of the hearts were weighted and used for conventional histology. Myocyte diameters (MD) were measured. Results: High SBP values were not associated with LVH in C group. Basal contractile parameters were depressed in SHR, R and C vs. WKY and L. The ISO at 10-5M was similar in WKY and L but remain depressed in C, R and SHR. *p<0.05 vs. L,H,WKY; **p<0.05 vs. L, H, WKY and SHR; # p<0.05 vs. L, H, C, and WKY; ***p<0.05 vs. SHR, R and C. Conclusions: L, H and C inhibited LVH in SHR and only L normalized the ISO response, suggesting that other factors different from hypertension, could participate in hypertrophy and beta inotropic response.