Cardiac Rehabilitation and Physical Performance in Patients after Myocardial Infarction: Preliminary Research

RNA-mediated epigenetic regulation in exercised heart: Mechanisms and opportunities for intervention

Physical exercise has been widely acknowledged as a beneficial lifestyle alteration and a potent non-pharmacological treatment for heart disease. Extensive investigations have revealed the beneficial effects of exercise on the heart and the underlying mechanisms involved. Exercise is considered one of the key factors that can lead to epigenetic alterations. The increasing number of identified molecules in the exercised heart has led to many studies in recent years that have explored the cellular function of ncRNAs and RNA modifications in the heart. Investigating the regulatory role of RNA-mediated epigenetic regulation in exercised hearts will contribute to the development of therapeutic strategies for the management of heart diseases. This review aims to summarize the positive impact of exercise on cardiac health. We will first provide an overview of the mechanisms through which exercise offers protection to the heart. Subsequently, we will delve into the current understanding of ncRNAs, specifically miRNAs, lncRNAs, and circRNAs, as well as RNA modification, focusing on RNA m6A and RNA A-to-I editing, and how they contribute to exercise-induced benefits for the heart. Lastly, we will explore the emerging therapeutic strategies that utilize exercise-mediated RNA epigenetic regulation in the treatment of heart diseases, while also addressing the challenges faced in this field.

Role of Cardiac Rehabilitation in Improving Outcomes After Myocardial Infarction

Myocardial infarction, an integral part of acute coronary syndrome (ACS), occurs due to atherosclerotic narrowing of the coronary (heart) blood vessels. Acute coronary syndrome, being one of the major cardiovascular diseases (CVDs), has led to a significant amount of mortality and morbidity, the majority of it due to MI. Over a long period following an MI, the physical, psychological, social, emotional, and occupational well-being are greatly impacted. Cardiac rehabilitation (CR) can address the above and help improve long-term well-being and overall quality of life. The benefits of CR include enhanced exercise capacity, risk factor reduction, improved quality of life (QOL), reduced mortality, and hospital readmissions. We used a systematic literature review (SLR) approach in this article to provide a global overview of cutting-edge CR in the post-MI phase. We reviewed 45 articles from journals of good repute published between 2013 and December 1st, 2023, focusing on seven selected papers for in-depth analysis. The analysis was focused on factors such as the positive outcomes of CR and the effects of CR post-MI. There are only a few statistically significant studies in a few domains of CR benefits, namely decreased mortality, cardiac events, depression, depression-associated mortality, hospital readmissions, increased left ventricular ejection fraction (LVEF), left ventricular end-diastolic dimension (LVEDD), left ventricular end-systolic volume (LVESV), metabolic equivalent of task (MET), maximal oxygen consumption (VO2max), and the six-minute walk test (6MWT), and as a result, increased physical performance. Further research is needed to enhance the understanding of its mechanisms and statistically prove its effectiveness in all other domains. As CR continues to evolve, referral and participation in CR should be increased as it improves overall health and well-being.

Cardiac and Pulmonary Rehabilitation: Two Underutilized Approaches with Some Unexpected Benefits

Although still underutilized [...].

CLINICAL, INSTRUMENTAL AND BIOCHEMICAL ASSOCIATIONS OF THE DEGREE OF PHYSICAL RECOVERY IN PATIENTS SUFFERED FROM ACUTE CORONARY SYNDROME AT THE COMPLETION OF IN-HOSPITAL REHABILITATION PERIOD

OBJECTIVE

The aim: To determine the clinical, instrumental and biochemical factors associated with the degree of physical recovery in patients suffered from acute coronary syndrome (ACS) at the completion of in-hospital rehabilitation period.

PATIENTS AND METHODS

Materials and methods: We enrolled 88 patients (all were males); 77 patients had ACS/STEMI and 11 with ACS/unstable angina. The mean age was (median, interquartile range) was 58 (49-64) years. We analyzed clinical, laboratory (including the circulating proprotein convertase subtilisin/kexin type 9 (PSK9) level in blood serum), transthoracic echocardiography and (urgent or delayed) coronary angiography data. Symptom-limited exercise tolerance (ET) test was performed predominantly at the second week of in-hospital stay. According to ET-test results, patients were subdivided into the groups with low (G1; 43 [48,9 %]) and high ET (G2; n=45 [51,1 %]).

RESULTS

Results: G1 (vs. G2) was characterized by older age, lower estimated glomerular filtration rate (eGFR) and higher left atrial (LA) dimension. The cases of any left anterior descending artery (LAD) lesion were more frequent in G1 (25 % vs. 2 % in G2, respectively; p=0,004). We revealed a decrease in PSK9 level after ET-test (pre-ET vs. post-ET: 824,0 (371,0-1073,0) vs. 676,0 (441,9-995,9) ng/ml, respectively; p=0,004 [N=35]).

CONCLUSION

Conclusions: At the completion of in-hospital rehabilitation period, the insufficient physical recovery in patients suffered from ACS associated with older age, lower eGFR, higher LA dimension, and more frequent any LDA lesion cases. Physical exercises favored the decrease in PCSK9 levels in blood serum.

Exercise training attenuates angiotensin II-induced cardiac fibrosis by reducing POU2F1 expression

PURPOSE

Exercise training protects against heart failure. However, the mechanism underlying the protective effect of exercise training on angiotensin II (Ang II)-induced cardiac fibrosis remains unclear.

METHODS

An exercise model involving C57BL/6N mice and 6 weeks of treadmill training was used. Ang II (1.44 mg/kg/day) was administered to induce cardiac fibrosis. RNA sequencing and bioinformatic analysis were used to identify the key factors mediating the effects of exercise training on cardiac fibrosis. Primary adult mouse cardiac fibroblasts (CFs) were used in vitro. Adeno-associated virus serotype 9 was used to overexpress POU domain, class 2, transcription factor 1 (POU2F1) in vivo.

RESULTS

Exercise training attenuated Ang II-induced cardiac fibrosis and reversed 39 gene expression changes. The transcription factor regulating the largest number of these genes was POU2F1. Compared to controls, POU2F1 was shown to be significantly upregulated by Ang II, which is itself reduced by exercise training. In vivo, POU2F1 overexpression nullified the benefits of exercise training on cardiac fibrosis. In CFs, POU2F1 promoted cardiac fibrosis. CCAAT enhancer-binding protein β (C/EBPβ) was predicted to be the transcription factor of POU2F1 and verified using a dual-luciferase reporter assay. In vivo, exercise training activated AMP-activated protein kinase (AMPK) and alleviated the increase in C/EBPβ induced by Ang II. In CFs, AMPK agonist inhibited the increase in C/EBPβ and POU2F1 induced by Ang II, whereas AMPK inhibitor reversed this effect.

CONCLUSION

Exercise training attenuates Ang II-induced cardiac fibrosis by reducing POU2F1. Exercise training inhibits POU2F1 by activating AMPK, which is followed by the downregulation of C/EBPβ, the transcription factor of POU2F1.

Influence of Risk Factors on Exercise Tolerance in Patients after Myocardial Infarction—Early Cardiac Rehabilitation in Poland

(1) Background: Prognosis in patients with cardiovascular diseases is significantly influenced by lifestyle and the control of risk factors. Patients after myocardial infarction require special care and promptly introduced cardiac rehabilitation. The primary aim of this study was to identify risk factors and their influence on exercise tolerance before and after cardiac rehabilitation (CR) provided under the Coordinated Specialist Care Programme—Infarct (CSC-Infarct). (2) Methods: The study was carried out at the Cardiac Rehabilitation Centre of Slupsk Specialist Hospital on a group of 112 patients aged 35–87 (62.78 ± 10.09 years) after myocardial infarction (MI), participating in CSC-Infarct. An exercise test (treadmill ECG test), the 6 min walk test (6MWT), echocardiography, blood test (total cholesterol, HDL, LDL, TG), measurement of diastolic pressure ratio (DPr), waist-to-hip ratio (WHR), and BMI were performed in participants on the first and last day of CR. Rating of perceived exertion was assessed with Borg’s scale. (3) Results: The overweight variable had the strongest effect on the increased value of initial: HR rest, HR max, and HR 1 min after exercise compared to subjects with normal BMI. DPr values before and after CR were also higher in overweight patients. Scores of 6MWT were higher in smokers compared to non-smokers. The final MET value was significantly higher in non-diabetic subjects. Hyperlipidaemia was associated with a higher initial HR max and initial HR 1 min after exercise. DPr before CR was also higher. The initial and final MET values were lower in hypertensive patients. Borg’s rating of perceived exertion measured after the final exercise test was also higher in hypertensive patients. Hypertension influenced the initial and final 6MWT scores, which were significantly higher in normotensive patients. (4) Conclusions: CR within CSC-infarction in patients after myocardial infarction improves exercise tolerance. Exercise tolerance in post-MI patients with concomitant risk factors is lower compared to post-MI patients without risk factors.

Exercise Training Alleviates Cardiac Fibrosis through Increasing Fibroblast Growth Factor 21 and Regulating TGF-β1-Smad2/3-MMP2/9 Signaling in Mice with Myocardial Infarction

Exercise training has been reported to alleviate cardiac fibrosis and ameliorate heart dysfunction after myocardial infarction (MI), but the molecular mechanism is still not fully clarified. Fibroblast growth factor 21 (FGF21) exerts a protective effect on the infarcted heart. This study investigates whether exercise training could increase FGF21 protein expression and regulate the transforming growth factor-β1 (TGF-β1)-Smad2/3-MMP2/9 signaling pathway to alleviate cardiac fibrosis following MI. Male wild type (WT) C57BL/6J mice and Fgf21 knockout (Fgf21 KO) mice were used to establish the MI model and subjected to five weeks of different types of exercise training. Both aerobic exercise training (AET) and resistance exercise training (RET) significantly alleviated cardiac dysfunction and fibrosis, up-regulated FGF21 protein expression, inhibited the activation of TGF-β1-Smad2/3-MMP2/9 signaling pathway and collagen production, and meanwhile, enhanced antioxidant capacity and reduced cell apoptosis in the infarcted heart. In contrast, knockout of Fgf21 weakened the cardioprotective effects of AET after MI. In vitro, cardiac fibroblasts (CFs) were isolated from neonatal mice hearts and treated with H₂O₂ (100 μM, 6 h). Recombinant human FGF21 (rhFGF21, 100 ng/mL, 15 h) and/or 5-Aminoimidazole-4-carboxamide ribonucleotide (AICAR, 1 mM, 15 h) inhibited H₂O₂-induced activation of the TGF-β1-Smad2/3-MMP2/9 signaling pathway, promoted CFs apoptosis and reduced collagen production. In conclusion, exercise training increases FGF21 protein expression, inactivates the TGF-β1-Smad2/3-MMP2/9 signaling pathway, alleviates cardiac fibrosis, oxidative stress, and cell apoptosis, and finally improves cardiac function in mice with MI. FGF21 plays an important role in the anti-fibrosis effect of exercise training.