Heterogeneity in Morphological Characteristics of Coronary Arteries and Aortae in Various Models of Hypertension

OBJECTIVE: Hypertension is associated with important structural and functional changes in vascular smooth muscle. The question arises whether different vascular beds and different models of hypertension react similarly or in a heterogeneous manner to the hypertensive state. METHODS: We quantitatively investigated the morphology of the coronary arteries and thoracic aortae taken from 4, 30 and 52-week-old spontaneously hypersensitive rats (SHR) and Wistar Kyoto rats (WKY), respectively, and from hypertensive rats with aortic stenosis (ASR). RESULTS: In coronary arteries taken from the SHR the media area was slightly increased compared with those obtained from the age-matched WKY. Increasing age caused a significant increase in media area of the SHR vessels, but not in WKY tissues. No differences were found in the media area values of the coronary arteries obtained from the ASR compared with those obtained from SHAM (operated control rats) rats. The media area of the aortae taken from SHR was increased when compared with those from the age-matched WKY rats. In addition, the media area of the aortae from the surgically induced aortic stenosis rats (ASR) when compared with tissues from SHAM rats was significantly increased. CONCLUSIONS: Different animal models of hypertension appear to develop largely heterogeneous profiles of vascular hypertrophy, with different morphometric characteristics.