Angiotensin-(1-7), an active fragment of both angiotensins I and II, generally opposes the vascular and proliferative actions of angiotensin II. Here we evaluated effects of the angiotensin-(1-7) receptor Mas on renal physiology and morphology using Mas-knockout mice. Compared to the wild-type animals, Mas knockout mice had significant reductions in urine volume and fractional sodium excretion without any significant change in free-water clearance. A significantly higher inulin clearance and microalbuminuria concomitant with a reduced renal blood flow suggest that glomerular hyperfiltration occurs in the knockout mice. Histological analysis found reduced glomerular tuft diameter and increased expression of collagen IV and fibronectin in the both the mesangium and interstitium, along with increased collagen III in the interstitium. These fibrogenic changes and the renal dysfunction of the knockout mice were associated with an upregulation of angiotensin II AT1 receptor and transforming growth factor-beta mRNA. Our study suggests that Mas acts as a critical regulator of renal fibrogenesis by controlling effects transduced through angiotensin II AT1 receptors in the kidney.

We have described a transgenic rat line that expresses an angiotensin-(1-7)-producing fusion protein, the TGR(A1-7)3292. In these rats, testis acts as an angiotensin-(1-7) biological pump, increasing its plasma concentration 2.5-fold. In this study, we performed hemodynamic measurements in TGR(A1-7)3292 and age-matched Hannover Sprague-Dawley (SD) control rats, using fluorescent microspheres. Urethane-anesthetized transgenic rats had similar levels of baseline blood pressure (99 +/- 3 mmHg) as did SD rats (101 +/- 3 mmHg). However, pronounced differences were observed in other hemodynamic measurements. TGR(A1-7)3292 rats presented a significant increase in stroke volume (0.29 +/- 0.01 vs. 0.25 +/- 0.01 ml in SD), increased cardiac index (24.6 +/- 0.91 vs. 21.9 +/- 0.65 ml.min(-1).kg) and decreased total peripheral resistance (3.9 +/- 0.13 vs. 4.5 +/- 0.13 mmHg.ml(-1).min.100 g). The increase in stroke volume in transgenic rats may be partially explained by the small decrease in heart rate (326 +/- 7.0 vs. 359 +/- 6.0 beats/min in SD). Strikingly, TGR(A1-7)3292 rats presented a substantial decrease in the vascular resistance in lung, spleen, kidney, adrenals, brain, testis and brown fat tissue with no significant differences in the left ventricle, mesentery, skin, gastrocnemius muscle and white fat tissue. These results corroborate and extend previous results observed after acute angiotensin-(1-7) infusion, showing that chronic increase in circulating angiotensin-(1-7) produces sustained and important changes in regional and systemic hemodynamics. Moreover, our data suggest a physiological role for angiotensin-(1-7) in the tonic control of regional blood flow.

These results suggest that the Ang-(1-7)/Mas axis plays an important role in regional and systemic hemodynamic adjustments in mice.

Introdução: A obesidade vem crescendo em crianças e adolescentes e isso já se tornou uma preocupação de saúde pública.Objetivo: O objetivo do estudo foi comparar e verificar a concordância entre 3 métodos indiretos para estimar a gordura corporal em crianças e adolescentes. Materiais e métodos:Participaram da amostra 90 crianças de ambos os gêneros, sendo 33 (meninos) e 57 (meninas), com uma idade média de 9.45±0.72 anos. Os métodos utilizados para avaliar a gordura corporal foram: 1) Bioimpedância Tetrapolar (BIA); Dobras Cutâneas (DC) e; Índice de Adiposidade Corporal (IAC). Na análise estatística foi utilizado o teste de Shapiro Wilk para verificar a distribuição da amostra. Para comparar os métodos entre os grupos foi adotado o teste Anova de Medidas Repetidas com a utilização do Post Hock de Bonferroni. Para verificar a concordância entre os métodos nas variáveis do estudo foi utilizada análise visual de Bland-Altman. O valor de p foi de p≤0.05. Resultados:Os resultados apontam que existiu concordância e correlação positiva entre os métodos estudados. Conclusão:Os métodos apresentaram confiabilidade na análise realizada, no entanto a BIA subestimou a gordura corporal, quando comparada aos demais métodos. | Abstract | Introduction:The incidence of obesity has increased in children and adolescents, and this has become an obvious concern for public health.