Altered regional blood flow distribution in Mas-deficient mice.

Giancarla Aparecida Botelho-Santos, Michael Bader, Nathalia Alenina, Robson Augusto Souza Santos

National Institute of Science and Technology in Nanobiopharmaceutics, Department of Physiology and Biophysics, ICBUFMG, Minas Gerais, Brazil.

Therapeutic advances in cardiovascular disease 2012 Oct

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We have recently shown that the acute infusion of angiotensin-(1-7) [Ang-(1-7)] or chronic increase in plasma Ang-(1-7) produces important changes in regional blood flow in rats. To further assess whether these changes are related to Mas, in this study hemodynamic measurements were performed in Ang-(1-7) receptor Mas knockout C57BL/6 (Mas-KO) mice and age-matched wild type (WT) control mice, using fluorescent microspheres. Mean arterial pressure in urethane-anesthetized Mas-KO mice (12-16 weeks old) did not differ from that in WT mice (79 ± 2 and 80 ± 2 mmHg respectively). However, pronounced differences were observed in other hemodynamic measurements. Mas-KO mice exhibited a significant decrease in stroke volume (0.03 ± 0.01 versus 0.05 ± 0.01 ml/beat in WT) and decreased cardiac index (0.81 ± 0.08 versus 1.24 ± 0.24 ml/min/g in WT). Strikingly, Mas-KO mice exhibited a marked increase in vascular resistance and a decrease in blood flow in the kidney, lung, adrenal gland, mesentery, spleen and brown fat tissue. The decrease in blood flow ranged from 34% (spleen) to 55% (brown fat tissue). These results suggest that the Ang-(1-7)/Mas axis plays an important role in regional and systemic hemodynamic adjustments in mice.

Citation

Giancarla Aparecida Botelho-Santos, Michael Bader, Nathalia Alenina, Robson Augusto Souza Santos. Altered regional blood flow distribution in Mas-deficient mice. Therapeutic advances in cardiovascular disease. 2012 Oct;6(5):201-11