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Aerobic exercise-induced cardiac hypertrophy (CH) is a physiological response involving accurate orchestration of gene and protein expression of contractile and metabolic components. The microRNAs: , and are each encoded by a myosin gene and thus are also known as 'MyomiRs', regulating several mRNA targets that in turn regulate CH and metabolic pathways. To understand the role of myomiRs in the fine-tuning of cardiac myosin heavy chain (MHC) isoform expression by exercise training-induced physiological hypertrophy, Wistar rats were subjected to two different swim training protocols. We observed that high-volume swim training (T2), improved cardiac diastolic function, induced CH and decreased the expression of and Consequently, the increased expression of their targets, sex determining region y-related transcription factor 6 (Sox6), Med13, Purβ, specificity proteins (Sp)/Krüppel-like transcription factor 3 (SP3) and HP1β (heterochromatin protein 1β) was more prominent in T2, thus converging to modulate cardiac metabolic and contractile adaptation by exercise training, with an improvement in the α-MHC/β-MHC ratio, bypassing the increase in PPARβ and histone deacetylase (HDAC) class I and II regulation. Altogether, we conclude that high-volume swim training finely assures physiological cardiac remodelling by epigenetic regulation of myomiRs, because inhibition of and increases the expression of their target proteins and stimulates the interaction among metabolic, contractile and epigenetic genes.

Hypothesis/Introduction: Polymorphisms of the angiotensin converting enzyme (ACE) gene can interfere with exercise-induced acute blood pressure (BP) reduction. This cross-over study investigated the acute effect of a single walk on BP and tested whether polymorphisms of the ACE gene might explain the variation in BP responses. Materials and methods: Thirty-four healthy medicated individuals were randomized to one control and one walking session at 60-75% of heart rate reserve. Subjects left the laboratory wearing an ambulatory BP monitor until waking the next morning. Results: Overall, systolic BP was somewhat lower following the walking session (p=.06), which could be attributed to a consistently lower systolic BP for 5 h after exercise (p-interaction<.04) compared with control rest. Similarly, II/ID individuals had a lower systolic BP (p-interaction=.02) and diastolic BP (p-interaction<.01) for 5 h after walking compared with control rest. Among DD individuals, a single walk did not induce a reduction in BP (p-interaction>.05). Conclusions: Our results showed that postexercise hypotension can occur after a walk at moderate intensity in carriers of the I allele; we were not able to demonstrate this in DD individuals. Our results suggest that genetic variation in the ACE gene might affect the BP response to exercise, although more research is needed to confirm these findings.

SummaryBackground: Functional variants of angiotensin-converting enzyme (ACE) gene may be associated with response to therapy in patients with heart failure (HF).

We tested the effects of early mesenchymal stem cell (MSC) therapy associated with endurance exercise on the structural and functional cardiac remodeling of rats with myocardial infarctation (MI). Male Wistar rats (40 days old) were divided into 6 groups: control and exercise sham; control and exercise MI; and control and exercise MI MSC. MI was surgically induced and bone marrow-derived MSCs were immediately injected via caudal vein (concentration: 1 × 10(6 )cells). Twenty-four hours later ET groups exercised on a treadmill (5 days/week; 60 min/day; 60% of maximal running velocity) for 12 weeks. Structural and functional changes were determined by echocardiography. Contractility and intracellular global calcium ([Ca(2 +)]i) transient were measured in myocytes from the left ventricular (LV) non-infarcted area. Calcium regulatory proteins were measured by Western blot. MI increased (p < 0.05) heart, ventricular and LV weights and its ratios to body weight; LV internal dimension in diastole (LVID-D) and in systole (LVID-S) and LV free wall in diastole (LVFW-D), but reduced the thickness of interventricular septum in systole (IVS-S), ejection fraction (EF) and fractional shortening (FS). MI augmented (p < 0.05) the times to peak and to half relaxation of cell shortening as well as the amplitude of the [Ca(2 +)]i transient and the times to peak and to half decay. Early MSCs therapy restored LVFW-D, IVS-S and the amplitude and time to half decay of the [Ca(2 +)]i transient. Early endurance exercise intervention increased (p < 0.05) LVFW-S, IVS-S, EF and FS, and reduced the times to peak and to half relaxation of cell shortening, and the amplitude of the [Ca(2 +)]i transient. Exercise training also increased the expression of left ventricular SERCA2a and PLBser16. Nevertheless, the combination of these therapies did not cause additive effects. In conclusion, combining early MSCs therapy and endurance exercise does not potentiate the benefits of such treatments to structural and functional cardiac remodeling in infarcted rats.

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Introduction:Previous studies have linked angiotensin-converting enzyme (ACE) insertion (I)/deletion (D) polymorphism (II, ID and DD) to physical performance. Moreover, ACE has two catalytic domains: NH2 (N) and COOH (C) with distinct functions, and their activity has been found to be modulated by ACE polymorphism. The aim of the present study is to investigate the effects of the interaction between aerobic exercise training (AET) and ACE I/D polymorphism on ACE N- and C-domain activities and vascular reactivity in humans.Materials and methods:A total of 315 pre-selected healthy males were genotyped for II, ID and DD genotypes. Fifty completed the full AET (II, n = 12; ID, n = 25; and DD, n = 13), performed in three 90-minute sessions weekly, in the four-month exercise protocol. Pre- and post-training resting heart rate (HR), peak O2 consumption (VO2 peak), mean blood pressure (MBP), forearm vascular conduction (FVC), total circulating ACE and C- and N-domain activities were assessed. One-way ANOVA and two-way repeated-measures ANOVA were used.Results:In pre-training, all variables were similar among the three genotypes. In post-training, a similar increase in FVC (35%) was observed in the three genotypes. AET increased VO2 peak similarly in II, ID and DD (49±2 vs. 57±1; 48±1 vs. 56±3; and 48±5 vs. 58±2 ml/kg/min, respectively). Moreover, there were no changes in HR and MBP. The DD genotype was also associated with greater ACE and C-domain activities at pre- and post-training when compared to II. AET decreased similarly the total ACE and C-domain activities in all genotypes, while increasing the N-domain activity in the II and DD genotypes. However, interestingly, the measurements of N-domain activity after training indicate a greater activity than the other genotypes. These results suggest that the vasodilation in response to AET may be associated with the decrease in total ACE and C-domain activities, regardless of genotype, and that the increase in N-domain activity is dependent on the DD genotype.Conclusions:AET differentially affects the ACE C- and N-domain activities, and the N-domain activity is dependent on ACE polymorphism.

The renin-angiotensin aldosterone system (RAAS) is associated with diverse physiological responses and adaptations to exercise. The angiotensin converting enzyme (ACE) 2 has vasodilatory effects, which might be associated with the blood pressure (BP) responses to acute exercise. The aim of this study was to investigate the role of ACE2 polymorphisms in postexercise hypotension (PEH). Thirty-four medicated hypertensive (61·3 ± 1·7 years, 76·1 ± 2·7 kg, 160 ± 1·6 cm) men (n = 12) and women (n = 22), participated in a control and a moderate intensity exercise session in a randomized order. After both experimental sessions, they left the laboratory wearing an ambulatory BP device for 24-h monitoring. ACE2 polymorphisms (Int-1 and Int-3) were assessed by polymerase chain reaction. Over the course of 5-h monitoring, we observed a significant reduction in SBP and DBP following exercise in the AA/AG of the Int-1 polymorphism (p-interaction = 0·02 and 0·001, respectively), whereas this could not be found in the individuals homozygous G (p-interaction = 0·76 and 0·51, respectively). With regard to Int-3 polymorphism, individuals AA/AG showed a significant reduction in SBP following exercise (p-interaction <0·0001) but not for DBP (p-interaction = 0·06) whereas GG individuals showed only a significant reduction in DBP following exercise (p-interaction = 0·02). Our results suggest that ACE2 polymorphism could affect PEH; however, larger trials are needed to confirm our findings.