Cardiovascular hypertrophy in one-kidney, one clip renal hypertensive rats: a role for angiotensin II?
OBJECTIVE
To investigate the role of angiotensin II (Ang II) in cardiovascular hypertrophy in the Goldblatt one-kidney, one clip (1-K, 1C) renal hypertensive rat.


METHODS
Six-week-old Wistar-Kyoto (WKY) rats underwent uninephrectomy and left renal artery clipping. After surgery, rats were treated with perindopril, an angiotensin converting enzyme (ACE) inhibitor, or losartan, an Ang II type 1 (AT1) receptor antagonist, for 4 weeks. Untreated 1-K, 1C rats and uninephrectomized (sham) rats served as controls.


RESULTS
The rise in systolic blood pressure in the perindopril-treated and losartan-treated rats was not significantly different from that in the untreated 1-K, 1C group throughout the treatment period. At 4 weeks after surgery the heart weight:body weight ratios of the untreated 1-K, 1C and losartan-treated 1-K, 1C groups were significantly greater than for sham-operated normotensive rats and hypertensive perindopril-treated rats. The total number of smooth muscle cells in the thoracic aortae of the 1-K, 1C untreated, losartan-treated 1-K, 1C and sham groups were similar. However, after treatment the aortae of the perindopril-treated group contained significantly fewer smooth muscle cells. The medial cross-sectional wall area and wall: lumen ratio were similar in the 1-K, 1C untreated and perindopril-treated 1-K, 1C groups.


CONCLUSIONS
These results suggest that Ang II, via its effects on cardiac and vascular AT1 receptors, does not contribute to the development of cardiovascular hypertrophy in the 1-K, 1C rat. Attenuation of cardiac and vascular growth after ACE inhibition appears to be mediated by mechanisms independent of the actions of the renin-angiotensin system.
Baker Medical Research Institute, University of Melbourne, Australia.
J B
JB
O'Sullivan
M J
MJ
Black
J F
JF
Bertram
A
A
Bobik
D000804:Angiotensin II / Q000502:physiology*; D057911:Angiotensin Receptor Antagonists; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000494:pharmacology; D000818:Animals; D001013:Aorta, Thoracic / Q000473:pathology*; D001713:Biphenyl Compounds / Q000494:pharmacology; D001794:Blood Pressure; D001835:Body Weight; D006332:Cardiomegaly / Q000473:pathology*; D006978:Hypertension, Renovascular / Q000473:pathology* / Q000503:physiopathology; D006984:Hypertrophy; D007093:Imidazoles / Q000494:pharmacology; D007211:Indoles / Q000494:pharmacology; D019808:Losartan; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000473:pathology*; D020913:Perindopril; D051381:Rats; D011921:Rats, Inbred WKY; D013777:Tetrazoles / Q000494:pharmacology
D057911:Angiotensin Receptor Antagonists; D000806:Angiotensin-Converting Enzyme Inhibitors; D001713:Biphenyl Compounds; D007093:Imidazoles; D007211:Indoles; D013777:Tetrazoles; D000804:Angiotensin II; D019808:Losartan; D020913:Perindopril