Pharmacological prevention and regression of arterial remodeling in a rat model of isolated systolic hypertension.
OBJECTIVE
Isolated systolic hypertension (ISH) is the predominant form of hypertension in the elderly population and drug treatment is unsatisfactory. We compared the efficacy of an endothelin-receptor antagonist (darusentan), an angiotensin-receptor blocker (irbesartan) and a thiazide diuretic (hydrochlorothiazide, HCTZ) to prevent and regress pulse pressure (PP) elevation and remodeling of large and small arteries, in a rat model of ISH obtained by the chronic administration of warfarin and vitamin K1 (WK).


RESULTS
Warfarin and vitamin K1 treatment for 4 or 8 weeks led to an elevation of PP, associated with increases in aortic calcium deposition and the ratio of collagen to elastin (C/E). Despite these changes in the composition of the aortic wall, the global structure of the aorta was unchanged. In contrast, an outward hypertrophic remodeling was observed in the middle cerebral artery. An early treatment with all drugs (darusentan, irbesartan, HCTZ) prevented PP elevation, changes of aortic media composition and the development of vascular remodeling. However, after 4 weeks of ISH, only darusentan and irbesartan reduced PP when administered from week 4 to 8. Darusentan was the most effective to regress existent aortic calcification, while only irbesartan reversed small artery hypertrophic remodeling.


CONCLUSIONS
During the development of ISH, drug treatment appears more beneficial when started early. Indeed, the three agents prevented PP elevation, aortic calcification and C/E increase in the aorta, and hypertrophy in small arteries. In contrast, once the disease is established, endothelin appears crucial in the maintenance of aortic calcification, while angiotensin II sustains small artery hypertrophy.
Dao
Huy Hao
HH
Faculty of Pharmacy, Université de Montréal, Montréal, Canada.
Essalihi
Rachida
R
Graillon
Jean-François
JF
Larivière
Richard
R
De Champlain
Jacques
J
Moreau
Pierre
P
D000818:Animals; D000959:Antihypertensive Agents / Q000627:therapeutic use*; D001013:Aorta, Thoracic / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D001158:Arteries / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology*; D001713:Biphenyl Compounds / Q000627:therapeutic use; D002114:Calcinosis / Q000188:drug therapy / Q000473:pathology; D003094:Collagen / Q000378:metabolism; D004195:Disease Models, Animal; D004549:Elastin / Q000378:metabolism; D006852:Hydrochlorothiazide / Q000627:therapeutic use; D006973:Hypertension / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology*; D000077405:Irbesartan; D008297:Male; D020768:Middle Cerebral Artery / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D010666:Phenylpropionates / Q000627:therapeutic use; D011743:Pyrimidines / Q000627:therapeutic use; D051381:Rats; D017208:Rats, Wistar; D013777:Tetrazoles / Q000627:therapeutic use
D000959:Antihypertensive Agents; D001713:Biphenyl Compounds; D010666:Phenylpropionates; D011743:Pyrimidines; D013777:Tetrazoles; D006852:Hydrochlorothiazide; C107831:darusentan; D003094:Collagen; D004549:Elastin; D000077405:Irbesartan