Authors:M. Matrai, B. Szekacs, M. Mericli, G. Nadasy, M. Szekeres, F. Banhidy, G. Bekesi, E. Monos and Szabolcs Várbíró
Hypertension causes small vessel remodeling, vasomotor alterations. We investigated diameter, tone and mechanics of intramural small coronaries of female rats that received chronic angiotensin treatment to induce hypertension.Angiotensin II infusion (AII, 100 ng/bwkg/min, sc.) was used to establish hypertension in 10 female rats. Other 10 rats served as controls. Following 4 weeks of treatment, side branches of the left anterior descendant coronary (diameter∼200 μm) were isolated, cannulated and pressure-diameter curves were registered between 2–90 mmHg. Changes in vessel diameter were measured in Krebs solution, in the presence of thromboxane A2 receptor agonist (U46619, 10−6M), bradykinin (BK, 10−6M), and finally at complete relaxation (in Ca2+-free solution).Chronic AII treatment raised the mean arterial pressure (130±5 mmHg vs. 96±2 mmHg, average ±SEM) significantly. Wall thickness of the AII group was significantly greater (40.2±4.2 μm vs. 31.4±2.7 μm at 50 mmHg in Ca2+-free solution), but cross-section of the vessel wall did not differ. Tangentional wall stress and elastic modulus decreased significantly in hypertensive animals. Constrictions in the presence of U46619 were greater in the AII group (24.4± 5.6% vs. 14.5±3.3% at 50 mmHg).In hypertension, intramural small coronaries showed inward eutrophic remodeling, as a morphological adaptation following AII treatment enhanced thromboxane A2 — induced tone.
Authors:Levente Sára, GyL. Nádasy, P. Antal, M. Szekeres, A. Monori-Kiss, E. Horváth, A. Tőkés, G. Masszi, E. Monos and Szabolcs Várbíró
To clarify the effects of dihydrotestosterone (DHT)-induced polycystic ovary syndrome (PCOS) on arteriolar biomechanics in a rat model and the possible modulatory role of vitamin D3.Methods and Results The PCOS model was induced in female Wistar rats by ten-weeks DHT treatment. Arteriolar biomechanics was tested in arterioles by pressure arteriography in control as well as DHT- and DHT with vitamin D3-treated animals in contracted and passive conditions. Increased wall stress and distensibility as well as increased vascular lumen were detected after DHT treatment. Concomitant vitamin D3 treatment lowered the mechanical load of the arterioles and restored the vascular diameter.Conclusion The hyperandrogenic state resulted in more rigid, less flexible arteriolar walls with increased vascular lumen compared with controls. DHT treatment caused eutrophic remodelling of gracilis arteriole. These prehypertensive alterations caused by chronic DHT treatment were mostly reversed by concomitant vitamin D3 administration.