Old spontaneously hypertensive rats gather together typical features of human chronic left-ventricular dysfunction with preserved ejection fraction.
OBJECTIVE
Heart failure with preserved left-ventricular ejection fraction (HF-PEF) is an entity leading to pulmonary congestion because of impaired diastolic filling. This syndrome usually strikes those who have experienced a long history of hypertension or metabolic risk factors. Pathophysiological mechanisms are not fully understood, and standard therapy is not established. Relevant preclinical models are still lacking. The aim of this work was to evaluate aging spontaneously hypertensive rats (SHRs) as a model of HF-PEF.


METHODS
Serial echocardiographic and blood pressure (BP) measurements were performed in 28, 36, 43, 47 and 51-week-old SHRs and their normotensive controls (Wistar-Kyoto rats). In 52-53-week-old animals, final investigations included ECG, invasive left-ventricular (LV) and aortic catheterization, brain natriuretic peptide (BNP) plasma concentrations, ventricular reverse transcription-qPCR evaluations (β-myosin heavy chain, atrial natriuretic peptide, BNP, sarco/endoplasmic reticulum calcium ATPase 2a and collagens 1a, 3a and 2a) and cardiac histology.


RESULTS
SHRs develop a progressive alteration of the early diastole, some of the echocardiographic parameters being not sensitive to BP reduction by the calcium blocker, nicardipine. The systolic function evaluated by echocardiography and invasive catheterization was preserved. When the observation period was over, an increase in collagen synthesis and deposits were identified in subendocardial layers. This attested a probable myocardial ischemia that was confirmed by ECG changes of the ST segment. BNP increased in the blood and at the mRNA level in the myocardium.


CONCLUSIONS
When aging, SHRs progressively develop HF-PEF showed by impaired LV relaxation and hypertrophy, BNP increase but preserved contractility and fibrosis. This model seems pertinent for further pharmacological preclinical studies in the field.
aLaboratoire de Neurobiologie et Pharmacologie Cardiovasculaire, Faculté de Médecine, Fédération de Médecine translationnelle, Université et Centre Hospitalier de Strasbourg, Strasbourg bMouse Clinical Institute, Illkirch-Graffenstaden, France.
Halim
H
Marzak
Estelle
E
Ayme-Dietrich
Roland
R
Lawson
Walid
W
Mokni
Roy
R
Combe
Julien
J
Becker
Lahcen El
LE
Fertak
Marie-France
MF
Champy
Laurent
L
Monassier
D000375:Aging; D000818:Animals; D001794:Blood Pressure; D001835:Body Weight; D003094:Collagen / Q000378:metabolism; D003971:Diastole; D004195:Disease Models, Animal; D004452:Echocardiography; D005355:Fibrosis; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D006333:Heart Failure / Q000503:physiopathology; D006339:Heart Rate; D006352:Heart Ventricles / Q000473:pathology; D006801:Humans; D008297:Male; D009200:Myocardial Contraction; D051381:Rats; D011918:Rats, Inbred SHR; D012307:Risk Factors; D018608:Ultrasonography, Doppler; D018487:Ventricular Dysfunction, Left / Q000503:physiopathology*; D016277:Ventricular Function, Left
D003094:Collagen