Aerobic exercise training leads to a physiological, non pathological left ventricular hypertrophy (LVH); however, the underlying biochemical and molecular mechanisms of physiological LVH are unknown. The role of microRNAs regulating the classic and the novel cardiac renin angiotensin system (RAS) was studied in trained rats assigned to three groups: sedentary, swimming trained with protocol 1 (T1: moderate volume training) and protocol 2 (T2: high volume training). Cardiac Ang I levels, ACE activity and protein expression, as well as Ang II levels were lower in T1 and T2, however AT1 mRNA levels (69% in T1 and 99% in T2) and protein expression (240% in T1 and 300% in T2) increased after training. AT2 receptor mRNA levels (220%) and protein expression (332%) were shown to be increased in T2. In addition, T1 and T2 were shown to increase ACE2 activity and protein expression, and Ang (1–7) levels in the heart. Exercise increased microRNA-27a and 27b, targeting ACE and decreasing microRNA-143 targeting ACE2 in the heart. LVH induced by aerobic training involves microRNAs regulation and an increase in cardiac AT1 receptor without the participation of Ang II. Parallel to this, increase in ACE2, Ang (1–7) and AT2 receptor in the heart by exercise suggests that this non classic cardiac RAS counteracts the classic cardiac RAS. These findings are consistent with a model in which exercise may induce LVH, at least in part, altering the expression of specific microRNAs targeting RAS genes. Together these effects might provide the additional aerobic capacity required by the exercised heart.

Alterations in the balance between ANG II/ACE and ANG 1-7/ACE2 in ANG II-dependent hypertension could reduce the generation of ANG 1-7 and contribute further to increased intrarenal ANG II. Upregulation of collecting duct (CD) renin may lead to increased ANG II formation during ANG II-dependent hypertension, thus contributing to this imbalance. We measured ANG I, ANG II, and ANG 1-7 contents, angiotensin-converting enzyme (ACE) and ACE2 gene expression, and renin activity in the renal cortex and medulla in the clipped kidneys (CK) and nonclipped kidneys (NCK) of 2K1C rats. After 3 wk of unilateral renal clipping, systolic blood pressure and plasma renin activity increased in 2K1C rats (n = 11) compared with sham rats (n = 9). Renal medullary angiotensin peptide levels were increased in 2K1C rats [ANG I: (CK = 171 ± 4; NCK = 251 ± 8 vs. sham = 55 ± 3 pg/g protein; P < 0.05); ANG II: (CK = 558 ± 79; NCK = 328 ± 18 vs. sham = 94 ± 7 pg/g protein; P < 0.001)]; and ANG 1-7 levels decreased (CK = 18 ± 2; NCK = 19 ± 2 pg/g vs. sham = 63 ± 10 pg/g; P < 0.001). In renal medullas of both kidneys of 2K1C rats, ACE mRNA levels and activity increased but ACE2 decreased. In further studies, we compared renal ACE and ACE2 mRNA levels and their activities from chronic ANG II-infused (n = 6) and sham-operated rats (n = 5). Although the ACE mRNA levels did not differ between ANG II rats and sham rats, the ANG II rats exhibited greater ACE activity and reduced ACE2 mRNA levels and activity. Renal medullary renin activity was similar in the CK and NCK of 2K1C rats but higher compared with sham. Thus, the differential regulation of ACE and ACE2 along with the upregulation of CD renin in both the CK and NCK in 2K1C hypertensive rats indicates that they are independent of perfusion pressure and contribute to the altered content of intrarenal ANG II and ANG 1-7.

BackgroundAccumulated evidence shows that the ACE-AngII-AT1 axis of the renin-angiotensin system (RAS) is markedly activated in chronic heart failure (CHF). Recent studies provide information that Angiotensin (Ang)-(1–7), a metabolite of AngII, counteracts the effects of AngII. However, this balance between AngII and Ang-(1–7) is still little understood in CHF. We investigated the effects of exercise training on circulating and skeletal muscle RAS in the ischemic model of CHF.Methods/Main ResultsMale Wistar rats underwent left coronary artery ligation or a Sham operation. They were divided into four groups: 1) Sedentary Sham (Sham-S), 2) exercise-trained Sham (Sham-Ex), sedentary CHF (CHF-S), and exercise-trained CHF (CHF-Ex). Angiotensin concentrations and ACE and ACE2 activity in the circulation and skeletal muscle (soleus and plantaris) were quantified. Skeletal muscle ACE and ACE2 protein expression, and AT1, AT2, and Mas receptor gene expression were also evaluated. CHF reduced ACE2 serum activity. Exercise training restored ACE2 and reduced ACE activity in CHF. Exercise training reduced plasma AngII concentration in both Sham and CHF rats and increased the Ang-(1–7)/AngII ratio in CHF rats. CHF and exercise training did not change skeletal muscle ACE and ACE2 activity and protein expression. CHF increased AngII levels in both soleus and plantaris muscle, and exercise training normalized them. Exercise training increased Ang-(1–7) in the plantaris muscle of CHF rats. The AT1 receptor was only increased in the soleus muscle of CHF rats, and exercise training normalized it. Exercise training increased the expression of the Mas receptor in the soleus muscle of both exercise-trained groups, and normalized it in plantaris muscle.ConclusionsExercise training causes a shift in RAS towards the Ang-(1–7)-Mas axis in skeletal muscle, which can be influenced by skeletal muscle metabolic characteristics. The changes in RAS circulation do not necessarily reflect the changes occurring in the RAS of skeletal muscle.

Although the use of exercise as a therapeutic tool has increased considerably, there is scarce information on the mechanisms conditioning the beneficial effects of training. Previous observations indicate the ability of training to reduce either the activity of the renin-angiotensin system (RAS), oxidative stress and inflammation. 10-12 By evaluating the effects of low-intensity aerobic training on the expression of brain RAS in cardiovascular-controlling areas of spontaneously hypertensive rats (SHR), we observed a prompt and robust training-induced reduction of either angiotensinogen (Aogen) ccumulating experimental evidence has shown that exercise training is an efficient and safe tool to counteract deleterious effects induced by hypertension, coronary artery disease and other cardiovascular diseases. 1-3 Exercise training promotes several cardiovascular adjustments in hypertensive and normotensive individuals, such as remodeling of the heart with a simultaneous stroke volume increase and heart rate (HR) decrease, 1,2,4,5 outward eutrophic remodeling of arteries and arterioles, capillary angiogenesis, and venule neoformation in the exercised muscles. 6-8 Aerobic training also restores impaired endothelial function in hypertensive animals and facilitates artery/arteriole vasodilatation. 2,9 These adaptive mechanisms, by reducing vascular resistance and improving both blood flow and tissue conductance, ameliorate Background: Hyperactivity of the renin-angiotensin system (RAS) and functional deficits in hypertension are reduced after exercise training. We evaluate in arteries, kidney and plasma of hypertensive rats the sequential effects of training on vascular angiotensinogen, Ang II and Ang (1-7) content.

Chronic angiotensin II (ANG II) infusion for 1 or 2 wk leads to progressive hypertension and induces inward hypertrophic remodeling in preglomerular vessels, which is associated with increased renal vascular resistance (RVR) and decreased glomerular perfusion. Considering the ability of preglomerular vessels to exhibit adaptive responses, the present study was performed to evaluate glomerular perfusion and renal function after 6 wk of ANG II infusion. To address this study, male Wistar rats were submitted to sham surgery (control) or osmotic minipump insertion (ANG II 200 ng·kg(-1)·min(-1), 42 days). A group of animals was treated or cotreated with losartan (10 mg·kg(-1)·day(-1)), an AT1 receptor antagonist, between days 28 and 42 Chronic ANG II infusion increased systolic blood pressure to 185 ± 4 compared with 108 ± 2 mmHg in control rats. Concomitantly, ANG II-induced hypertension increased intrarenal ANG II level and consequently, preglomerular and glomerular injury. Under this condition, ANG II enhanced the total renal plasma flow (RPF), glomerular filtration rate (GFR), urine flow and induced pressure natriuresis. These changes were accompanied by lower RVR and enlargement of the lumen of interlobular arteries and afferent arterioles, consistent with impairment of renal autoregulatory capability and outward preglomerular remodeling. The glomerular injury culminated with podocyte effacement, albuminuria, tubulointerstitial macrophage infiltration and intrarenal extracellular matrix accumulation. Losartan attenuated most of the effects of ANG II. Our findings provide new information regarding the contribution of ANG II infusion over 2 wk to renal hemodynamics and function via the AT1 receptor.

This study was conducted to evaluate time-dependent pharmacokinetic changes and drug interactions over the first 6 months after transplantation in kidney transplant recipients receiving tacrolimus (TAC), prednisone (PRED) and mycophenolate mofetil (MMF) or sirolimus (SRL). Pharmacokinetic assessments were carried out at day 7 and months 1, 3, and 6 in kidney transplant recipients receiving TAC plus PRED with either MMF (2 g/day, n = 13) or SRL (15 mg loading dose, 5 mg for 7 days followed by 2 mg/day, n = 12). There were no differences in the main demographic characteristics or in mean PRED doses during the first 6 months after transplant. From day 7 to month 6, there was a 65% increase in TAC dose corrected exposure (dose corrected area under the curve; AUC) in patients receiving MMF (P = 0.005) and a 59% increase in TAC dose corrected exposure in patients receiving SRL (P = 0.008). From day 7 to month 6, there was a 72% increase in mycophenolate dose corrected exposure (P = 0.001) and a 65% increase in SRL dose corrected exposure (P = 0.008). TAC dose corrected exposure was 23% lower in patients receiving SRL compared with MMF (P = 0.012) on average over the study period. PRED dose reduction was associated with increase in TAC (in patients receiving SRL, P = 0.040) and mycophenolic acid (MPA) (P = 0.070) drug exposures. Tercile distribution of TAC drug exposure showed a positive correlation with mean SRL exposures (P = 0.016). Conversely, tercile distribution of SRL drug exposure showed a positive correlation with mean TAC exposures (P = 0.004). Time-dependent increases in TAC, MPA and SRL drug exposures occur up to 6 months after transplantation. Drug-to-drug interactions indicate that intense therapeutic drug monitoring is required to avoid under- or over-immunosuppression.

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3DE facilitates EOA measurement in pediatric AS and correlates with change in aortic valve gradient after balloon valvuloplasty.