trandolapril and Vascular-Diseases

The effect of the specific endothelin (A) (ET(A))-receptor antagonist LU 302146 (LU) was assessed in a normotensive model of chronic transplant vasculopathy, i.e. orthotopic allotransplantation of the infrarenal abdominal aorta from spontaneously hypertensive-to-Wistar-Kyoto (SHR-to-WKY) rats. A second experimental setting was used to confirm the results in a different model, which to some extent may also address the issue of blood pressure (BP) in transplant vasculopathy, i.e. orthotopic allotransplantation of infrarenal abdominal aorta from WKY-to-SHR rats. Untreated sham-operated and isografted WKY and SHR served as controls. Allotransplanted animals treated with the angiotensin-converting enzyme (ACE) inhibitor trandolapril served as positive treatment controls.. Rats were randomized to receive standard diet or a diet designed to deliver either 30 mg LU/kg bw/day, 0.3 mg/kg bw/day trandolapril or a combination of both. The duration of either experiment was 8 weeks. BP was measured by tail plethysmography.. Treatment with LU did not affect systolic BP in either experimental setting. In contrast, trandolapril and combination treatment significantly reduced systolic BP in SHRs. The increase in aortic wall thickness (given in mm) was abrogated to a similar extent in the three treatment groups as compared with untreated allotransplanted animals in either experimental setting (e.g. WKY sham-operated 0.084 +/- 0.013, P < 0.05 vs treatment groups; WKY isotransplanted 0.100 +/- 0.010, P < 0.05 vs treatment groups; WKY allotransplanted 0.289 +/- 0.077, P < 0.05 vs all groups; WKY allotransplanted + trandolapril 0.185 +/- 0.025; WKY allotransplanted + LU 301246 0.192 +/- 0.049; WKY allotransplanted + LU 301246 + trandolapril 0.190 +/- 0.041). This was due to an attenuation of the increase of intima and media thickness. Treatment with LU and trandolapril were similarly effective in attenuating the increase of the number of proliferating cell nuclear antigen (PCNA)-positive cells in the intima. Again, combination treatment did not confer additional benefit. In contrast, trandolapril was more effective than LU in attenuating the increase in the number of PCNA-positive cells in the media. Trandolapril or combination treatment, but not LU, attenuated transforming growth factor-beta expression in aortic allografts.. The ET(A)-receptor blockade abrogates allograft vasculopathy in two different aorta allotransplantation models to a similar extent as ACE inhibition even in the absence of concomitant immunosuppression. At least in SHRs the effect of ET(A)-receptor blockade is independent of BP. This finding is consistent with the notion that ET(A)-receptor mediated events play a partly BP-independent role in the genesis of chronic transplant vasculopathy.

Topics: Angiotensin-Converting Enzyme Inhibitors; Animals; Aorta; Benzhydryl Compounds; Blood Pressure; Drug Therapy, Combination; Endothelin Receptor Antagonists; Indoles; Male; Pyrimidines; Rats; Rats, Inbred SHR; Rats, Inbred WKY; Receptor, Endothelin A; Transplantation, Homologous; Vascular Diseases

We compared the chronic effects in spontaneously hypertensive rats (SHR) of low doses of an angiotensin converting enzyme inhibitor, trandolapril, a Ca2+ channel antagonist, verapamil, and their combination (trandolapril-verapamil), on arterial mechanical properties, arterial wall hypertrophy and extracellular matrix proteins. Four-week-old SHR were randomly allocated to oral treatment with verapamil (50 mg kg(-1) day(-1)), trandolapril (0.3 mg kg(-1) day(-1)), the combination of verapamil (50 mg kg(-1) day(-1)) plus trandolapril (0.3 mg kg(-1) day(-1)), or placebo for 4 months. A group of Wistar Kyoto (WKY) control rats received placebo for the same period of time. At the end of the treatment, mean blood pressure was lower in verapamil-trandolapril than in trandolapril SHR, but remained higher than in WKY. Verapamil had no effects on blood pressure. Equivalent reduction in aortic wall hypertrophy was obtained in all treated SHR. Trandolapril and verapamil-trandolapril combination produced a significant reduction of aortic collagen density compared with placebo SHR. Carotid total fibronectin, EIIIA fibronectin isoform and alpha5beta1 integrin, were higher in the media of placebo SHR than in WKY. EIIIA fibronectin isoform and alpha5beta1 integrin were reduced in verapamil-SHR compared with placebo-SHR and normalized in trandolapril and verapamil-trandolapril-SHR compared with WKY. SHR-placebo and SHR treated with either verapamil or trandolapril as single-drug treatment showed a 4-fold increase in total fibronectin compared to the WKY. Only SHR treated with verapamil-trandolapril combination had total fibronectin not significantly different from that of WKY. Carotid arterial distensibility increased only in verapamil-trandolapril treated rats. Multivariate analysis showed arterial distensibility to be negatively correlated to mean blood pressure (P < 0.0001) and total fibronectin (P < 0.01). In conclusion, chronic treatment with the verapamil-trandolapril combination significantly improved in vivo arterial distensibility in SHR. The most important effects of the combination on arterial mechanics compared to those of verapamil or trandolapril alone may have been the consequence of its stronger action on arterial pressure, arterial wall hypertrophy and total fibronectin density. However we suggest that, in addition to the structural effects, complete normalization of blood pressure is necessary to obtain normal arterial distensibility.

Topics: Angiotensin-Converting Enzyme Inhibitors; Animals; Antigens, CD; Aorta, Thoracic; Arteries; Blood Pressure; Body Weight; Calcium Channel Blockers; Carotid Arteries; Fibronectins; Heart Rate; Hypertension; Hypertrophy; Indoles; Integrin alpha5; Male; Rats; Rats, Inbred SHR; Rats, Inbred WKY; Time Factors; Vascular Diseases; Verapamil