NG-nitro-L-arginine-methyl ester (L-NAME)-induced hypertension is associated with protein remodeling of the left ventricle. The aim of the study was to show, whether aldosterone receptor blocker spironolactone and precursor of NOproduction L-arginine were able to reverse the protein rebuilding of the left ventricle. Six groups of male Wistar rats were investigated: control 4 (4 weeks placebo), L-NAME (4 weeks L-NAME), spontaneous-regression (4 weeks L-NAME + 3 weeks placebo), spironolactone-regression (4 weeks L-NAME + 3 weeks spironolactone), L-arginineregression (4 weeks L-NAME + 3 weeks arginine), control 7 (7 weeks placebo). L-NAME administration induced hypertension, hypertrophy of the left ventricle (LV), and the increase of metabolic and contractile as well as soluble and insoluble collagenous protein concentration. The systolic blood pressure and relative weight of the LV decreased in all three groups with regression, while the most prominent attenuation of the LVH was observed after spironolactone treatment. In the spontaneous-regression and L-arginine-regression groups the concentrations of individual proteins were not significantly different from the control value. However, in the spironolactone-regression group the concentration of metabolic, contractile and insoluble collagenous proteins remained significantly increased in comparison with the control group. The persistence of the increased protein concentration in the spironolactone group may be related to the more prominent reduction of myocardial water content by spironolactone., F. Šimko, A. Potáčová, V. Pelouch, L'. Paulis, J. Matúšková, K. Krajčírovičová, O. Pecháňová, M. Adamcová., and Obsahuje bibliografii
We compared graft outcome between two types of a novel
composite three-layer carp-collagen-coated vascular graft in
low-flow conditions in a sheep model. Collagen in group A
underwent more cycles of purification than in group B in order to
increase the ratio between collagen and residual fat. The grafts
were implanted end-to-side in both carotid arteries in sheep
(14 grafts in 7 sheep in group A, 18 grafts in 9 sheep in group B)
and artificially stenosed on the right side. The flow in the grafts
in group A decreased from 297±118 ml/min to 158±159 ml/min
(p=0.041) after placement of the artificial stenosis in group A,
and from 330±164ml/min to 97±29 ml/min (p=0.0052) in
group B (p=0.27 between the groups). From the five surviving
animals in group A, both grafts occluded in one animal 3 and 14
days after implantation. In group B, from the six surviving
animals, only one graft on the left side remained patent
(p=0.0017). Histology showed degradation of the intimal layer in
the center with endothelization from the periphery in group A
and formation of thick fibrous intimal layer in group B. We
conclude that the ratio between collagen and lipid content in the
novel three-layer graft plays a critical role in its patency and
structural changes in vivo.
The effect of chronic administration of angiotensin converting enzyme inhibitor on the development of hypoxic pulmonary hypertension was studied in rats. Male Wistar rats were exposed for 3 weeks to isobaric hypoxia (10 % O2) and treated with 10 mg/kg b.w. of Ramipril daily. The haemodynamic properties of the pulmonary vasculature were then measured in isolated blood-perfused lung preparation. Ramipril administration during the sojourn in hypoxia resulted in lower baseline perfusion pressure and lower slope of perfusion pressure-flow relationship compared to non-treated hypoxic rats. Partitioning of the distribution of pulmonary vascular resistance across the vascular bed by the occlusion technique showed that it was mainly due to a decrease of arterial and venous vascular resistances to blood flow. It is suggested that Ramipril attenuates the process of morphological reconstruction of pulmonary vasculature by chronic hypoxia rather than the level of vascular smooth muscle tone.