Exercise Preconditioning as a Cardioprotective Phenotype

Aerobic interval training preconditioning protocols inhibit isoproterenol-induced pathological cardiac remodeling in rats: Implications on oxidative balance, autophagy, and apoptosis

This study aimed to investigate the potential cardioprotective effects of moderate and high-intensity aerobic interval training (MIIT and HIIT) preconditioning. The focus was on histological changes, pro-oxidant-antioxidant balance, autophagy initiation, and apoptosis in myocardial tissue incited by isoproterenol-induced pathological cardiac remodeling (ISO-induced PCR). Male Wistar rats were randomly divided into control (n ​= ​6), ISO (n ​= ​8), MIIT (n ​= ​4), HIIT (n ​= ​4), MIIT ​+ ​ISO (n ​= ​8), and HIIT ​+ ​ISO (n ​= ​8) groups. The MIIT and HIIT protocols were administered for 10 weeks, followed by the induction of cardiac remodeling using subcutaneous injection of ISO (100 ​mg/kg for two consecutive days). Alterations in heart rate (HR), mean arterial pressure (MAP), rate pressure product (RPP), myocardial oxygen consumption (MV ˙ O2), cardiac hypertrophy, histopathological changes, pro-oxidant-antioxidant balance, autophagy biomarkers (Beclin-1, Atg7, p62, LC3 I/II), and apoptotic cell distribution were measured. The findings revealed that the MIIT ​+ ​ISO and HIIT ​+ ​ISO groups demonstrated diminished myocardial damage, hemorrhage, immune cell infiltration, edema, necrosis, and apoptosis compared to ISO-induced rats. MIIT and HIIT preconditioning mitigated HR, enhanced MAP, and preserved MV ˙ O2 and RPP. The pro-oxidant-antioxidant balance was sustained in both MIIT ​+ ​ISO and HIIT ​+ ​ISO groups, with MIIT primarily inhibiting pro-apoptotic autophagy progression through maintaining pro-oxidant-antioxidant balance, and HIIT promoting pro-survival autophagy. The results demonstrated the beneficial effects of both MIIT and HIIT as AITs preconditioning in ameliorating ISO-induced PCR by improving exercise capacity, hemodynamic parameters, and histopathological changes. Some of these protective effects can be attributed to the modulation of cardiac apoptosis, autophagy, and oxidative stress.

Assessment of clinical depression metrics in cardiac patients using the patient health Questionnaire-9 before and after phase-II cardiac rehabilitation

Cardiovascular disease remains a leading cause of morbidity and mortality, a fact that is commonly associated with co-morbidities such as clinical depression. While phase II cardiac rehabilitation is an established intervention for those with cardiovascular disease, its effect on patients who also suffer from depression are under studied. Aim: To quantify Pre- and Post-cardiac rehabilitation questionnaire scores collected from a large patient data registry. For this investigation, 27 ​670 patients completed Patient Health Questionnaire-9 questionnaires both Pre- and Post-rehabilitation (averaging [28.0 ​± ​8.7] phase II sessions). Findings reveal that questionnaire scores decreased by 40%-48% across all groups, a finding that was independent of assigned sex, race, and ethnicity. Moreover, when data were stratified for questionnaire scores that may indicate major and minor depressive disorder, phase II cardiac rehabilitation outcomes were lower by 61% and 49% respectively. While all groups exhibited lower questionnaire scores following cardiac rehabilitation participation, numerical differences at Pre- and Post-rehabilitation time points indicate that males and White patients have more favorable scores. This latter observation, while not confirmed currently, appears to be linked to referral rates to phase II cardiac rehabilitation, which remain poor for females, racial and ethnic minorities.

Position Statement of the Italian Society of Cardiovascular Prevention (SIPREC) and Italian Heart Failure Association (ITAHFA) on Cardiac Rehabilitation and Protection Programs as a Cornerstone of Secondary Prevention after Myocardial Infarction or Revascularization

Despite the remarkable and progressive advances made in the prevention and management of cardiovascular diseases, the recurrence of cardiovascular events remains unacceptably elevated with a notable size of the residual risk. Indeed, in patients who suffered from myocardial infarction or who underwent percutaneous or surgical myocardial revascularization, life-style changes and optimized pharmacological therapy with antiplatelet drugs, lipid lowering agents, beta-blockers, renin angiotensin system inhibitors and antidiabetic drugs, when appropriate, are systematically prescribed but they might be insufficient to protect from further events. In such a context, an increasing body of evidence supports the benefits of cardiac rehabilitation (CR) in the setting of secondary cardiovascular prevention, consisting in the reduction of myocardial oxygen demands, in the inhibition of atherosclerotic plaque progression and in an improvement of exercise performance, quality of life and survival. However, prescription and implementation of CR programs is still not sufficiently considered.The aim of this position paper of the Italian Society of Cardiovascular Prevention (SIPREC) and of the Italian Heart Failure Association (ITAHFA) is to examine the reasons of the insufficient use of this strategy in clinical practice and to propose some feasible solutions to overcome this clinical gap.

An Interdisciplinary Intervention Based on Prescription of Physical Activity, Diet, and Positive Mental Health to Promote Healthy Lifestyle in Patients with Obesity: A Randomized Control Trial

This study used a multimodal approach to address the issue of obesity among individuals with a Body Mass Index (BMI) between 30 and 40 residing in a rural region of north-east Spain. A pretest-posttest model was employed in a clinical trial design, comparing an intervention group with a control group. The intervention, which lasted for a period of nine months, was based on three main strategies: the prescription of physical activity, the promotion of healthy nutritional habits, and the management of emotional wellbeing through Positive Mental Health (PMH). A variety of assessment tools were employed, including the CLASS-AF scale and a stress test for physical activity levels; advanced anthropometry and blood analysis for metabolic and body composition variables; a Mediterranean diet adherence questionnaire for nutritional habits; and a PMH multifactorial questionnaire for the assessment of emotional management. The results revealed significant improvements in the level of physical activity and adherence to the Mediterranean diet in favor of the intervention group, where 89.4% (n = 17) of the participants went from being not very active/sedentary to being active. Also, adherence to the Mediterranean diet improved with a mean increase of 2.2 points on the scale [mean: 10.5 (CI 95%: 9.90, 11.09)]. In addition, significant reductions in body fat [mean: -2.50 kg (CI 95%: -3.56, -1.44)] and free fat mass [mean: -3.38% (IC 95%: -4.34, -2.41), along with decreased cholesterol levels (196 vs. 182 mg/dL), were observed, suggesting a decrease in cardiovascular and metabolic risk. In conclusion, this multimodal intervention was effective at improving the lifestyle of people with obesity and reducing their cardiovascular and metabolic risk. The combination of interventions focused on physical activity, diet, Positive Mental Health, and metabolic changes and were perceived as a comprehensive and complementary strategy in obesity care. These findings highlight the importance of approaching this condition from multiple perspectives to ensure optimal health outcomes.

Physical Activity, Cardiorespiratory Fitness and Atherosclerotic Cardiovascular Disease: Part 1

Background

The cardioprotective benefits and prognostic significance of regular moderate-to-vigorous physical activity (PA), increased cardiorespiratory fitness (CRF), or both are often underappreciated by the medical community and the patients they serve. Individuals with low CRF are two to three times more likely to die prematurely from atherosclerotic cardiovascular disease (CVD), than their fitter counterparts when matched for risk factor profile or coronary artery calcium (CAC) score. Accordingly, part 1 of this 2-part review examines these relations and the potential underlying mechanisms of benefit (e.g., exercise preconditioning) on atherosclerotic CVD, with specific reference to gait speed and mortality, CRF and PA as separate risk factors, and the relation between CRF and/or PA on attenuating the adverse impact of an elevated CAC score, as well as potentially favorably modifying CAC morphology, and on incident atrial fibrillation, all-cause and cardiovascular mortality, and on sudden cardiac death (SCD).

Summary

We explore the underappreciated cardioprotective effects of regular PA and CRF. Part 1 examines how CRF and PA reduce the risk of premature death from atherosclerotic CVD by investigating their roles as separate risk factors, the potential underlying mechanisms of benefit, and their impact on gait speed, mortality, and atrial fibrillation. The review also addresses how CRF and PA may mitigate the adverse impact of an elevated CAC score, potentially modifying CAC morphology, and reduce the risk of SCD.

Key Messages

Regular PA and high CRF are essential for reducing the risk of premature death from CVD and mitigating the negative impact of elevated CAC scores. Additionally, they provide significant protection against SCD and atrial fibrillation, emphasizing their broad cardioprotective effects.

Exercise preconditioning promotes myocardial GLUT4 translocation and induces autophagy to alleviate exhaustive exercise-induced myocardial injury in rats

Exercise preconditioning (EP) is a line of scientific inquiry into the short-term biochemical mediators of cardioprotection in the heart. This study examined the involvement of autophagy induced by energy metabolism in myocardial remodelling by EP and myocardial protection. A total of 120 healthy male Sprague Dawley (SD) rats were randomly divided into six groups. Plasma cTnI, HBFP staining and electrocardiographic indicators were examined in the context of myocardial ischemic/hypoxic injury and protection. Western blotting and fluorescence double labelling were used to investigate the relationship between energy metabolism and autophagy in EP-resistant myocardial injury caused by exhaustive exercise. Compared with those in the C group, the levels of myocardial ischemic/hypoxic injury were significantly increased in the EE group. Compared with those in the EE group, the levels of myocardial ischemic/hypoxic injury were significantly decreased in the EEP + EE and LEP + EE groups. Compared with that in the EE group, the level of GLUT4 in the sarcolemma was significantly increased, and the colocalization of GLUT4 with the sarcolemma was significantly increased in the EEP + EE and LEP + EE groups (P < 0.05). LC3-II and LC3-II/LC3-I levels of the EEP + EE group were significantly elevated compared with those in the EE group (P < 0.05). The levels of p62 were significantly decreased in the EEP + EE and LEP + EE groups compared with the EE group (P < 0.05). EP promotes GLUT4 translocation and induced autophagy to alleviate exhaustive exercise-induced myocardial ischemic/hypoxic injury.

Micro- and Macrovascular Effects of Inflammation in Peripheral Artery Disease-Pathophysiology and Translational Therapeutic Approaches

Inflammation has a critical role in the development and progression of atherosclerosis. On the molecular level, inflammatory pathways negatively impact endothelial barrier properties and thus, tissue homeostasis. Conformational changes and destruction of the glycocalyx further promote pro-inflammatory pathways also contributing to pro-coagulability and a prothrombotic state. In addition, changes in the extracellular matrix composition lead to (peri-)vascular remodelling and alterations of the vessel wall, e.g., aneurysm formation. Moreover, progressive fibrosis leads to reduced tissue perfusion due to loss of functional capillaries. The present review aims at discussing the molecular and clinical effects of inflammatory processes on the micro- and macrovasculature with a focus on peripheral artery disease.

Exercise training and experimental myocardial ischemia and reperfusion: A systematic review and meta-analysis

Background

Despite the success of interventional coronary reperfusion strategies, morbidity and mortality from acute myocardial infarction are still substantial. Physical exercise is a well-recognized effective non-pharmacological therapy for cardiovascular diseases. Therefore, the objective of this systematic review was to analyze studies in animal models of ischemia-reperfusion in association with physical exercise protocols.

Search strategy

Articles published on the topic over a 13-year period (2010-2022) were searched in two databases (PubMed and Google Scholar) using the keywords exercise training, ischemia/reperfusion or ischemia reperfusion injury. Meta-analysis and quality assessment of the studies were performed using the Review Manager 5.3 program.

Results

From the 238 articles retrieved from PubMed and 200 from Google Scholar, after screening and eligibility assessment, 26 articles were included in the systematic review and meta-analysis. For meta-analysis comparing the group of previously exercised animals with the non-exercised animals and then submitted to ischemia-reperfusion, the infarct size was significantly decreased by exercise (p < 0.00001). In addition, the group exercised had increased heart-to-body weight ratio (p < 0.00001) and improved ejection fraction as measured by echocardiography (p < 0.0004) in comparison to non-exercised animals.

Conclusion

We concluded that the animal models of ischemia-reperfusion indicates that exercise reduce infarct size and preserve ejection fraction, associated with beneficial myocardial remodeling.

Myokine Musclin Is Critical for Exercise-Induced Cardiac Conditioning

This study investigates the role and mechanisms by which the myokine musclin promotes exercise-induced cardiac conditioning. Exercise is one of the most powerful triggers of cardiac conditioning with proven benefits for healthy and diseased hearts. There is an emerging understanding that muscles produce and secrete myokines, which mediate local and systemic "crosstalk" to promote exercise tolerance and overall health, including cardiac conditioning. The myokine musclin, highly conserved across animal species, has been shown to be upregulated in response to physical activity. However, musclin effects on exercise-induced cardiac conditioning are not established. Following completion of a treadmill exercise protocol, wild type (WT) mice and mice with disruption of the musclin-encoding gene, Ostn, had their hearts extracted and exposed to an ex vivo ischemia-reperfusion protocol or biochemical studies. Disruption of musclin signaling abolished the ability of exercise to mitigate cardiac ischemic injury. This impaired cardioprotection was associated with reduced mitochondrial content and function linked to blunted cyclic guanosine monophosphate (cGMP) signaling. Genetic deletion of musclin reduced the nuclear abundance of protein kinase G (PKGI) and cyclic adenosine monophosphate (cAMP) response element binding (CREB), resulting in suppression of the master regulator of mitochondrial biogenesis, peroxisome proliferator-activated receptor γ coactivator 1α (PGC1α), and its downstream targets in response to physical activity. Synthetic musclin peptide pharmacokinetic parameters were defined and used to calculate the infusion rate necessary to maintain its plasma level comparable to that observed after exercise. This infusion was found to reproduce the cardioprotective benefits of exercise in sedentary WT and Ostn-KO mice. Musclin is essential for exercise-induced cardiac protection. Boosting musclin signaling might serve as a novel therapeutic strategy for cardioprotection.

Cardiac electrophysiological remodeling associated with enhanced arrhythmia susceptibility in a canine model of elite exercise

The health benefits of regular physical exercise are well known. Even so, there is increasing evidence that the exercise regimes of elite athletes can evoke cardiac arrhythmias including ventricular fibrillation and even sudden cardiac death (SCD). The mechanism of exercise-induced arrhythmia and SCD is poorly understood. Here, we show that chronic training in a canine model (12 sedentary and 12 trained dogs) that mimics the regime of elite athletes induces electrophysiological remodeling (measured by ECG, patch-clamp, and immunocytochemical techniques) resulting in increases of both the trigger and the substrate for ventricular arrhythmias. Thus, 4 months sustained training lengthened ventricular repolarization (QTc: 237.1±3.4 ms vs. 213.6±2.8 ms, n=12; APD90: 472.8±29.6 ms vs. 370.1±32.7 ms, n=29 vs. 25), decreased transient outward potassium current (6.4±0.5 pA/pF vs. 8.8±0.9 pA/pF at 50 mV, n=54 vs. 42), and increased the short-term variability of repolarization (29.5±3.8 ms vs. 17.5±4.0 ms, n=27 vs. 18). Left ventricular fibrosis and HCN4 protein expression were also enhanced. These changes were associated with enhanced ectopic activity (number of escape beats from 0/hr to 29.7±20.3/hr) in vivo and arrhythmia susceptibility (elicited ventricular fibrillation: 3 of 10 sedentary dogs vs. 6 of 10 trained dogs). Our findings provide in vivo, cellular electrophysiological and molecular biological evidence for the enhanced susceptibility to ventricular arrhythmia in an experimental large animal model of endurance training.

Physical Activity and Cardiorespiratory Fitness as Modulators of Health Outcomes: A Compelling Research-Based Case Presented to the Medical Community

The beneficial health effects and prognostic significance of regular moderate-to-vigorous physical activity (PA), increased cardiorespiratory fitness (CRF), or both are often underappreciated by the medical community and the patients they serve. Individuals with low CRF have higher annual health care costs, higher rates of surgical complications, and are two to three times more likely to die prematurely than their fitter counterparts when matched for risk factor profile or coronary calcium score. Increased levels of habitual PA before hospitalization for acute coronary syndromes are also associated with better short-term cardiovascular outcomes. Accordingly, this review examines these relations and the potential underlying mechanisms of benefit (eg, exercise preconditioning), with specific reference to the incidence of cardiovascular, cancer, and coronavirus diseases, and the prescriptive implications and exercise thresholds for optimizing health outcomes. To assess the evidence supporting or refuting the benefits of PA and CRF, we performed a literature search (PubMed) and critically reviewed the evidence to date. In aggregate, these data are presented in the context of clarifying the impact that regular PA and/or increased CRF have on preventing and treating chronic and infectious diseases, with reference to evidence-based exercise thresholds that the medical community can embrace and promote.

Hybrid and Traditional Cardiac Rehabilitation in a Rural Area: A RETROSPECTIVE STUDY

PURPOSE

Cardiac rehabilitation is a prescribed exercise intervention that reduces cardiovascular mortality, secondary events, and hospitalizations. Hybrid cardiac rehabilitation (HBCR) is an alternative method that overcomes barriers to participation, such as travel distance and transportation issues. To date, comparisons of HBCR and traditional cardiac rehabilitation (TCR) are limited to randomized controlled trials, which may influence outcomes due to supervision associated with clinical research. Coincidental to the COVID-19 pandemic, we investigated HBCR effectiveness (peak metabolic equivalents [peak METs]), resting heart rate (RHR), resting systolic (SBP) and diastolic blood pressure (DBP), body mass index (BMI), and depression outcomes (Patient Health Questionnaire-9 [PHQ-9]).

METHODS

Via retrospective analysis, TCR and HBCR were examined during the COVID-19 pandemic (October 1, 2020, and March 31, 2022). Key dependent variables were quantified at baseline (pre) and discharge (post). Completion was determined by participation in 18 monitored TCR exercise sessions and four monitored HBCR exercise sessions.

RESULTS

Peak METs increased at post-TCR and HBCR (P < .001); however, TCR resulted in greater improvements (P = .034). The PHQ-9 scores were decreased in all groups (P < .001), while post-SBP and BMI did not improve (SBP: P = .185, BMI: P = .355). Post-DBP and RHR increased (DBP: P = .003, RHR: P = .032), although associations between intervention and program completion were not observed (P = .172).

CONCLUSIONS

Peak METs and depression metric outcomes (PHQ-9) improved with TCR and HBCR. Improvements in exercise capacity were greater with TCR; however, HBCR did not produce inferior results by comparison, an outcome that may have been essential during the first 18 mo of the COVID-19 pandemic.

Interaction of Cardiovascular Nonmodifiable Risk Factors, Comorbidities and Comedications With Ischemia/Reperfusion Injury and Cardioprotection by Pharmacological Treatments and Ischemic Conditioning

Preconditioning, postconditioning, and remote conditioning of the myocardium enhance the ability of the heart to withstand a prolonged ischemia/reperfusion insult and the potential to provide novel therapeutic paradigms for cardioprotection. While many signaling pathways leading to endogenous cardioprotection have been elucidated in experimental studies over the past 30 years, no cardioprotective drug is on the market yet for that indication. One likely major reason for this failure to translate cardioprotection into patient benefit is the lack of rigorous and systematic preclinical evaluation of promising cardioprotective therapies prior to their clinical evaluation, since ischemic heart disease in humans is a complex disorder caused by or associated with cardiovascular risk factors and comorbidities. These risk factors and comorbidities induce fundamental alterations in cellular signaling cascades that affect the development of ischemia/reperfusion injury and responses to cardioprotective interventions. Moreover, some of the medications used to treat these comorbidities may impact on cardioprotection by again modifying cellular signaling pathways. The aim of this article is to review the recent evidence that cardiovascular risk factors as well as comorbidities and their medications may modify the response to cardioprotective interventions. We emphasize the critical need for taking into account the presence of cardiovascular risk factors as well as comorbidities and their concomitant medications when designing preclinical studies for the identification and validation of cardioprotective drug targets and clinical studies. This will hopefully maximize the success rate of developing rational approaches to effective cardioprotective therapies for the majority of patients with multiple comorbidities. SIGNIFICANCE STATEMENT: Ischemic heart disease is a major cause of mortality; however, there are still no cardioprotective drugs on the market. Most studies on cardioprotection have been undertaken in animal models of ischemia/reperfusion in the absence of comorbidities; however, ischemic heart disease develops with other systemic disorders (e.g., hypertension, hyperlipidemia, diabetes, atherosclerosis). Here we focus on the preclinical and clinical evidence showing how these comorbidities and their routine medications affect ischemia/reperfusion injury and interfere with cardioprotective strategies.

The response to the COVID-19 pandemic: With hindsight what lessons can we learn?

The purpose of this paper is to put forward some evidence-based lessons that can be learned from how to respond to a Pandemic that relate to healthy living behaviours (HLB). A 4-step methodology was followed to conduct a narrative review of the literature and to present a professional practice vignette. The narrative review identified 8 lessons: 1) peer review; 2) historical perspectives; 3) investing in resilience and protection; 4) unintended consequences; 5) protecting physical activity; 6) school closures; 7) mental health; and 8) obesity. As in all probability there will be another Pandemic, it is important that the lessons learned over the last three years in relation to HLB are acted upon. Whilst there will not always be a consensus on what to emphasise, it is important that many evidence-based positions are presented. The authors of this paper recognise that this work is a starting point and that the lessons presented here will need to be revisited as new evidence becomes available.

Physical activity, cardiorespiratory fitness, and cardiovascular health: A clinical practice statement of the ASPC Part I: Bioenergetics, contemporary physical activity recommendations, benefits, risks, extreme exercise regimens, potential maladaptations

Regular moderate-to-vigorous physical activity (PA) and increased levels of cardiorespiratory fitness (CRF) or aerobic capacity are widely promoted as cardioprotective measures in the primary and secondary prevention of atherosclerotic cardiovascular (CV) disease (CVD). Nevertheless, physical inactivity and sedentary behaviors remain a worldwide concern. The continuing coronavirus (COVID-19) pandemic has been especially devastating to patients with known or occult CVD since sitting time and recreational PA have been reported to increase and decrease by 28% and 33%, respectively. Herein, in this first of a 2-part series, we discuss foundational factors in exercise programming, with specific reference to energy metabolism, contemporary PA recommendations, the dose-response relationship of exercise as medicine, the benefits of regular exercise training, including the exercise preconditioning cardioprotective phenotype, as well as the CV risks of PA. Finally, we discuss the 'extreme exercise hypothesis,' specifically the potential maladaptations resulting from high-volume, high-intensity training programs, including accelerated coronary artery calcification and incident atrial fibrillation. The latter is commonly depicted by a reverse J-shaped or U-shaped curve. On the other hand, longevity data argue against this relationship, as elite endurance athletes live 3-6 years longer than the general population.

Cardioprotective effects of preconditioning exercise in the female tumor bearing mouse

Cancer cachexia, a metabolic wasting syndrome, affects up to 80% of cancer patients and leads to the death in up to 20% of cancer patients. While research is growing in the field, there are still no clear diagnostic criteria and cancer cachexia remains an untreated condition. Aerobic exercise has been shown to positively impact cachexia by slowing its development and attenuating muscle loss. The most effective timing, duration, and intensity of exercise as a preventative and protective measure against cancer cachexia remains questionable. Therefore, the purpose of this study was to examine the effects of preconditioning exercise as a protective measure for tumor-mediated muscle wasting. Female LC3 Tg+ and wildtype mice were randomly separated into four groups, sedentary non-tumor bearing (SED + NT), sedentary tumor bearing (SED + T), treadmill exercise non-tumor bearing (TM + NT), and treadmill exercise tumor bearing (TM + T). Mice underwent an 8-week treadmill exercise training protocol (TM) or remained sedentary (SED). Next, mice were implanted with tumor cells (T group; 5 × 105 Lewis Lung Carcinoma cells in flank) or remained non-tumor (NT) for 4 weeks. Tumor bearing resulted in a significant decline in cardiac function. SED + T showed a significant decrease in fractional shortening (p &lt; 0.05) when compared to the other groups. This coincided with an increase in beclin-1 and MyD88 protein expression and decrease in p-FOXO1 (inactivated) protein expression in SED + T mice. Interestingly, preconditioning exercise (exercise prior to tumor bearing) appeared to preserve cardiac function (TM + T not significantly different than SED + NT). Exercise-mediated cardioprotection also coincided with abolished beclin-1 and MyD88 signaling that was not significantly elevated in TM + T mice. Additionally, TM resulted in a 22-fold decrease in estimated tumor volume (p &lt; 0.05) and a 45% decrease in tumor mass (p &lt; 0.05) compared to SED tumors. The data indicate potential cardioprotective effects of preconditioning exercise on preserving cardiac structure and function, as well as regulating autophagic (beclin-1), inflammatory (TGF-β and MyD88), and atrophy (p-FOXO1) pathways during tumor bearing. Preconditioning exercise may be an effective and accessible treatment intervention for early-stage cancer survivors. This data is crucial in identifying the significance of exercise and the timing of exercise as a protective measure against the detrimental effects of cancer cachexia.

Prophylactic exercise-derived circulating exosomal miR-125a-5p promotes endogenous revascularization after hindlimb ischemia by targeting endothelin converting enzyme 1

Background

Prophylactic exercise improves clinical outcomes in patients experiencing severe ischemic diseases. Previous studies have shown that exercise could alter the amount or content of circulating exosomes. However, little is known about the role of precursory exercise-derived circulating exosomes (Exe-Exo) in ischemic diseases. We therefore aimed to explore the function and mechanism of Exe-Exo in endogenous revascularization and perfusion recovery in peripheral arterial disease.

Methods and Results

We first determined that 4 weeks of precursory treadmill exercise improved perfusion recovery on days 7, 14 and 21 after unilateral femoral artery ligation (FAL) but had no effect immediately after ligation. Then, local muscle delivery of Exe-Exo promotes arteriogenesis, angiogenesis and perfusion recovery, which could be abolished by GW4869, a well-recognized pharmacological agent inhibiting exosome release. This suggests that Exe-Exo mediated exercise-induced revascularization. In vitro, Exe-Exo enhanced endothelial cell proliferation, migration and tube formation. In addition, we identified miR-125a-5p as a novel exerkine through exosomal miRNA sequencing and RT-qPCR validation. Inhibition of miR-125a-5p abrogated the beneficial effects of Exe-Exo both in vivo and in vitro. Mechanistically, these exercise-afforded benefits were attributed to the exosomal miR-125a-5p downregulation of ECE1 expression and the subsequent activation of the AKT/eNOS downstream signaling pathway. Specifically, skeletal muscle may be a major tissue source of exercise-induced exosomal miR-125a-5p via fluorescence in situ hybridization.

Conclusions

Endogenous circulating exosomal miR-125a-5p promotes exercise-induced revascularization via targeting ECE1 and activating AKT/eNOS downstream signaling pathway. Identify exosomal miR-125a-5p as a novel exerkine, and highlight its potential therapeutic role in the prevention and treatment of peripheral arterial disease.

Compositions and Functions of Mitochondria-Associated Endoplasmic Reticulum Membranes and Their Contribution to Cardioprotection by Exercise Preconditioning

Mitochondria-associated endoplasmic reticulum membranes (MAMs) are important components of intracellular signaling and contribute to the regulation of intracellular Ca²⁺/lipid homeostasis, mitochondrial dynamics, autophagy/mitophagy, apoptosis, and inflammation. Multiple studies have shown that proteins located on MAMs mediate cardioprotection. Exercise preconditioning (EP) has been shown to protect the myocardium from adverse stimuli, but these mechanisms are still being explored. Recently, a growing body of evidence points to MAMs, suggesting that exercise or EP may be involved in cardioprotection by modulating proteins on MAMs and subsequently affecting MAMs. In this review, we summarize the latest findings on MAMs, analyzing the structure and function of MAMs and the role of MAM-related proteins in cardioprotection. We focused on the possible mechanisms by which exercise or EP can modulate the involvement of MAMs in cardioprotection. We found that EP may affect MAMs by regulating changes in MFN2, MFN1, AMPK, FUNDC1, BECN1, VDAC1, GRP75, IP3R, CYPD, GSK3β, AKT, NLRP3, GRP78, and LC3, thus playing a cardioprotective role. We also provided direction for future studies that may be of interest so that more in-depth studies can be conducted to elucidate the relationship between EP and cardioprotection.

Aging, sex and NLRP3 inflammasome in cardiac ischaemic disease

Experimentally, many strong cardioprotective treatments have been identified in different animal models of acute ischaemia/reperfusion injury (IRI) and coronary artery disease (CAD). However, the translation of these cardioprotective therapies for the benefit of the patients into the clinical scenario has been very disappointing. The reasons for this lack are certainly multiple. Indeed, many confounding factors we must deal in clinical reality, such as aging, sex and inflammatory processes are neglected in many experiments. Due to the pivotal role of aging, sex and inflammation in determining cardiac ischaemic disease, in this review, we take into account age as a modifier of tolerance to IRI in the two sexes, dissecting aging and myocardial reperfusion injury mechanisms and the sex differences in tolerance to IRI. Then we focus on the role of the gut microbiota and the NLRP3 inflammasome in myocardial IRI and on the possibility to consider NLRP3 inflammasome as a potential target in the treatment of CAD in relationship with age and sex. Finally, we consider the cardioprotective mechanisms and cardioprotective treatments during aging in the two sexes.

Impact of Social Disparities on Cardiovascular Disease and COVID-19 Outcomes: BARRIERS TO CARE AND PREVENTIVE INTERVENTIONS

The COVID-19 pandemic has exposed significant disparities within certain population subsets that manifest through greater disease burden and worse outcomes. In this commentary, we propose specific preventive interventions to address these disparities within the United States.

Chronic Stress, Exercise and Cardiovascular Disease: Placing the Benefits and Risks of Physical Activity into Perspective

Chronic stress, which has been exacerbated worldwide by the lingering COVID pandemic, has been strongly linked to cardiovascular disease (CVD). In addition, autonomic dysregulation via sustained sympathetic activity has been shown to increase the risk of arrhythmias, platelet aggregation, acute coronary syndromes and heart failure. Fortunately, effective coping strategies have been shown to attenuate the magnitude of hyperarousal associated with the stress response, including moderate-to-vigorous lifestyle activity and/or structured exercise. A good-to-excellent level of cardiorespiratory fitness also appears to be highly cardioprotective. These beneficial effects have been substantiated by numerous studies that have evaluated the levels of stress reactivity and stress recovery in physically active individuals versus matched sedentary controls, as well as before and after exercise interventions. On the other hand, unaccustomed strenuous exercise in habitually sedentary persons with underlying CVD is associated with a disproportionate incidence of acute cardiac events. Moreover, extreme exercise regimens appear to increase coronary calcification and the likelihood of developing atrial fibrillation. This review summarizes these relations and more, with specific reference to placing the benefits and risks of physical activity into perspective.

From Exercise to Cognitive Performance: Role of Irisin

The beneficial effects of exercise on the brain are well known. In general, exercise offers an effective way to improve cognitive function in all ages, particularly in the elderly, who are considered the most vulnerable to neurodegenerative disorders. In this regard, myokines, hormones secreted by muscle in response to exercise, have recently gained attention as beneficial mediators. Irisin is a novel exercise-induced myokine, that modulates several bodily processes, such as glucose homeostasis, and reduces systemic inflammation. Irisin is cleaved from fibronectin type III domain containing 5 (FNDC5), a transmembrane precursor protein expressed in muscle under the control of peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α). The FNDC5/irisin system is also expressed in the hippocampus, where it stimulates the expression of the neurotrophin brain-derived neurotrophic factor in this area that is associated with learning and memory. In this review, we aimed to discuss the role of irisin as a key mediator of the beneficial effects of exercise on synaptic plasticity and memory in the elderly, suggesting its roles within the main promoters of the beneficial effects of exercise on the brain.

Swimming exercise improves short- and long-term memories: Time-course changes

The beneficial effects of exercise training on memory formation are well documented. However, the memory enhancement profile following the time-course of exercise training remains unknown. In this investigation, changes in the spatial hippocampal memory following a time-course of swimming exercise training were examined. Young adult Wistar rats were tested for both short-term and long-term memories using the radial arm water maize (RAWM) paradigm following 0, 1, 7, 14, and 28 days of swimming exercise training (60 min per day, 5 days/week)s. The mean total errors on RAWM during the learning phase and memory testing remained the same (p > 0.5) after 1 day of swimming exercise. On the other hand, swimming exercise-induced significant enhancement to the learning phase and memory formation after 7 days of training (p < 0.01). Errors decreased (p < 0.0001) after 7 days of training and remained lower (p < 0.0001) than baseline without differences between 7, 14, and 28 days (p > 0.5). Similarly, short- and long-term memories improved after 7 days (p < 0.05) of training as compared to the baseline without differences between 7, 14, and 28 days (p > 0.05). The time course of improvement of learning and both short- and long-term memories after swimming exercise were evident after 7 days and plateaued thereafter. Results of the current study could form the base for future utilization of exercises to enhance cognitive function in healthy individuals.