Nara Yumi Hashimoto

Aerobic Exercise Training–Induced Left Ventricular Hypertrophy Involves Regulatory MicroRNAs, Decreased Angiotensin-Converting Enzyme-Angiotensin II, and Synergistic Regulation of Angiotensin-Converting Enzyme 2-Angiotensin (1-7)

Aerobic exercise training leads to a physiological, nonpathological left ventricular hypertrophy; however, the underlying biochemical and molecular mechanisms of physiological left ventricular hypertrophy are unknown. The role of microRNAs regulating the classic and the novel cardiac renin-angiotensin (Ang) system was studied in trained rats assigned to 3 groups: (1) sedentary; (2) swimming trained with protocol 1 (T1, moderate-volume training); and (3) protocol 2 (T2, high-volume training). Cardiac Ang I levels, Ang-converting enzyme (ACE) activity, and protein expression, as well as Ang II levels, were lower in T1 and T2; however, Ang II type 1 receptor mRNA levels (69% in T1 and 99% in T2) and protein expression (240% in T1 and 300% in T2) increased after training. Ang II type 2 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. Left ventricular hypertrophy induced by aerobic training involves microRNA regulation and an increase in cardiac Ang II type 1 receptor without the participation of Ang II. Parallel to this, an increase in ACE2, Ang (1-7), and Ang II type 2 receptor in the heart by exercise suggests that this nonclassic cardiac renin-angiotensin system counteracts the classic cardiac renin-angiotensin system. These findings are consistent with a model in which exercise may induce left ventricular hypertrophy, at least in part, altering the expression of specific microRNAs targeting renin-angiotensin system genes. Together these effects might provide the additional aerobic capacity required by the exercised heart.

Characterization of angiotensin-converting enzymes 1 and 2 in the soleus and plantaris muscles of rats

Angiotensin-converting enzymes 1 (ACE1) and 2 (ACE2) are key enzymes of the renin-angiotensin system, which act antagonistically to regulate the levels of angiotensin II (Ang II) and Ang-(1-7). Considerable data show that ACE1 acts on normal skeletal muscle functions and architecture. However, little is known about ACE1 levels in muscles with different fiber compositions. Furthermore, ACE2 levels in skeletal muscle are not known. Therefore, the purpose of this study was to characterize protein expression and ACE1 and ACE2 activities in the soleus and plantaris muscles. Eight-week-old female Wistar rats (N = 8) were killed by decapitation and the muscle tissues harvested for biochemical and molecular analyses. ACE1 and ACE2 activities were investigated by a fluorometric method using Abz-FRK(Dnp)P-OH and Mca-YVADAPK(Dnp)-OH fluorogenic substrates, respectively. ACE1 and ACE2 protein expression was analyzed by Western blot. ACE2 was expressed in the skeletal muscle of rats. There was no difference between the soleus (type I) and plantaris (type II) muscles in terms of ACE2 activity (17.35 ± 1.7 vs 15.09 ± 0.8 uF·min(-1)·mg(-1), respectively) and protein expression. ACE1 activity was higher in the plantaris muscle than in the soleus (71.5 ± 3.9 vs 57.9 ± 1.1 uF·min(-1)·mg(-1), respectively). Moreover, a comparative dose-response curve of protein expression was established in the soleus and plantaris muscles, which indicated higher ACE1 levels in the plantaris muscle. The present findings showed similar ACE2 levels in the soleus and plantaris muscles that might result in a similar Ang II response; however, lower ACE1 levels could attenuate Ang II production and reduce bradykinin degradation in the soleus muscle compared to the plantaris. These effects should enhance the aerobic capacity necessary for oxidative muscle activity.

Influence of angiotensinogen and angiotensin-converting enzyme polymorphisms on cardiac hypertrophy and improvement on maximal aerobic capacity caused by exercise training.

Background The allele threonine (T) of the angiotensinogen has been associated with ventricular hypertrophy in hypertensive patients and soccer players. However, the long-term effect of physical exercise in healthy athletes carrying the T allele remains unknown. We investigated the influence of methionine (M) or T allele of the angiotensinogen and D or I allele of the angiotensin-converting enzyme on left-ventricular mass index (LVMI) and maximal aerobic capacity in young healthy individuals after long-term physical exercise training. Design Prospective clinical trial. Methods Eighty-three policemen aged between 20 and 35 years (mean ± SD 26 ± 4.5 years) were genotyped for the M235T gene angiotensinogen polymorphism (TT, n = 25; MM/MT, n = 58) and angiotensin-converting enzyme gene insertion/deletion (I/D) polymorphism (II, n = 18; DD/DI, n = 65). Left-ventricular morphology was evaluated by echocardiography and maximal aerobic capacity (VO2peak) by cardiopulmonary exercise test before and after 17 weeks of exercise training (50–80% VO2peak). Results Baseline VO2peak and LVMI were similar between TT and MM/MT groups, and II and DD/DI groups. Exercise training increased significantly and similarly VO2peak in homozygous TT and MM/MT individuals, and homozygous II and DD/DI individuals. In addition, exercise training increased significantly LVMI in TT and MM/MT individuals (76.5 ± 3 vs. 86.7 ± 4, P = 0.00001 and 76.2 ± 2 vs. 81.4 ± 2, P = 0.00001, respectively), and II and DD/DI individuals (77.7 ± 4 vs. 81.5 ± 4, P = 0.0001 and 76 ± 2 vs. 83.5 ± 2, P = 0.0001, respectively). However, LVMI in TT individuals was significantly greater than in MM/MT individuals (P = 0.04). LVMI was not different between II and DD/DI individuals. Conclusion Left-ventricular hypertrophy caused by exercise training is exacerbated in homozygous TT individuals with angiotensinogen polymorphism.

O grau de melhora na função das células progenitoras endoteliais derivadas da medula óssea é dependente do volume de treinamento físico aeróbio

INTRODUCTION: Skeletal muscle angiogenesis induced by aerobic exercise training (ET) is crucial in the improvement of the aerobic capacity. The endothelial progenitor cells (EPC) derived from bone marrow have been described for promoting both the vascular repair and angiogenesis. Although the role of the ET on the parameters of the EPC has been investigated, the effect of different volumes of ET on the EPC function in bone marrow, skeletal muscle metabolic alterations and capilarization are unknown. OBJECTIVE: We hypothesized that ET improves the EPC function in bone marrow, accompanied by an increase of skeletal muscle oxidative capacity and angiogenesis dependents of the increase of volume of ET. METHODS: Twenty one Wistar rats were divided into 3 groups: sedentary control (SC), trained protocol 1 (T1) and trained protocol 2 (T2). T1: swimming training consisted of 60 min, 1x/day/10weeks, with 5% body weight load. T2 the same as T1 until 8th week, in the 9th week the rats trained 2x/day and in the 10th week 3x/day. RESULTS: ET promoted resting bradycardia, increase of exercise tolerance, peak oxygen uptake and citrate synthase enzyme activity in the T1 group, being these adaptative responses exacerbate in the P2 group, indicating that the aerobic condition was improved in this group. ET improved the EPC function of the bone marrow in T1, and the response was exacerbed in T2 group. In parallel, an increase in the number of capillaries dependent of ET volume was also observed. CONCLUSION: These findings suggest that the bone marrow as the main reservoir of EPC is influenced by different ET volume, possibly being responsible for the improvement of aerobic performance observed by higher endogenous EPC mobilization, active participants in the process of angiogenesis induced by ET.

Nandrolone increases angiotensin-I converting enzyme activity in rats tendons

INTRODUCCION: El sistema renina-angiotensina (RAS) ha sido asociado con varios procesos biologicos del cuerpo humano, entre ellos, regular la presion arterial y el contenido de electrolitos. Ademas, el RAS tambien regula el tejido conectivo. Recientemente, estudios han demostrado que el uso de nandrolona modifica la actividad de ACE e incrementa la deposicion de colageno en el corazon. OBJETIVO: En este modo, el objetivo del estudio fue evaluar la actividad de la enzima de conversion angiotensina (ACE) en el tendon flexor superficial (TFS) y en el suero despues del ejercicio de resistencia en combinacion con la administracion de esteroides anabolico-androgenicos (AAS) despues de la sesion de entrenamiento, y seis semanas de desentrenamiento. METODOS: Cuarenta y ocho ratones Wistar fueron divididos en dos grupos (G1 y G2) y subdivididos en cuatro grupos: sedentarios (S); entrenados (T); ratas sedentarias tratadas con AAS (Deca-Durabolin(r) - 5 mg / kg dos veces a la semana) (AAS) y animales entrenados y tratados con AAS (AAST). Los grupos entrenados realizaron saltos en el agua: cuatro series de 10 saltos cada uno, con 30 segundos de intervalo entre las series, durante siete semanas. RESULTADOS: El entrenamiento aumento la actividad de ECA en TFS en comparacion con el control (p <0,05). Los grupos AAS y AAST mostraron mayores niveles de ACE (p <0,05). El grupo AAST mostro alta actividad de ECA en comparacion con el grupo T. Ademas, el AAST mostro niveles mas altos de ACE en el suero. En G2, todos los grupos disminuyeron la la actividad ACE tanto en el suero como en el tendon si comparados con el grupo control. CONCLUSION: Este estudio indica que la administracion de AAS y su combinacion con el ejercicio aumenta la actividad de ECA en los tendones. El uso abusivo de AAS puede comprometer la adaptacion del tendon, lo que puede causar remodelaciones mal adaptativas.