Gender-related differences in left ventricular remodeling in chronic severe aortic valve regurgitation in rats.
OBJECTIVE
Aortic valve regurgitation (AR) can result in heart failure from chronic overloading of the left ventricle. As little is known of gender-specific responses of the left ventricle to this condition, the study aim was to compare left ventricular (LV) remodeling in male and female rats with severe AR. In order to assess the impact of estrogens on LV remodeling in AR, the effect of ovariectomy (OVX) was also evaluated.


METHODS
AR was created in adult Wistar rats (females (control or OVX) and males). Animals were followed for 26 weeks and compared to sham-operated groups. Heart function was evaluated in vivo using echocardiography, and the hearts were subsequently harvested for tissue analysis.


RESULTS
The LV ejection fraction was decreased similarly in both sexes. Despite similar echocardiographic AR severity, females had higher indexed cardiac output and the largest increase in LV weight, cardiomyocyte hypertrophy and eccentric remodeling. No differences were observed between control and OVX females. Ovariectomy had no significant impact on any of the parameters monitored.


CONCLUSIONS
Female rats developed more LV remodeling in response to chronic AR than males. AR appears to impose a greater LV workload on females due to their smaller body and heart size. Hormonal status did not have any impact on LV remodeling in this experimental model.
Drolet
Marie-Claude
MC
Groupe de recherche en valvulopathies, Centre de Recherche Hôpital Laval, Institut de Cardiologie de Québec, Université Laval, Québec QC, Canada.
Lachance
Dominic
D
Plante
Eric
E
Roussel
Elise
E
Couet
Jacques
J
Arsenault
Marie
M
D000818:Animals; D001022:Aortic Valve Insufficiency / Q000000981:diagnostic imaging / Q000503:physiopathology*; D003094:Collagen / Q000235:genetics; D004195:Disease Models, Animal; D004452:Echocardiography; D005260:Female; D005353:Fibronectins / Q000235:genetics; D008297:Male; D009929:Organ Size; D010052:Ovariectomy; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D017208:Rats, Wistar; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012727:Sex Characteristics; D020257:Ventricular Remodeling
D005353:Fibronectins; D012333:RNA, Messenger; D003094:Collagen