Exercise induced Right Ventricular Fibrosis is Associated with Myocardial Damage and Inflammation

Right ventricular remodeling induced by prolonged excessive endurance exercise is mediated by upregulating Wnt/β-catenin signaling in rats

BACKGROUND

The aim of this study was to develop an animal model to investigate whether prolonged intensive endurance exercise induces RV remodeling, taking into account the involvement of Wnt/β-catenin signaling.

METHODS

Four-week-old male Wistar rats (100 to 125 g) were assigned to four groups (n = 8/group): 1) sixteen weeks of intensive (36 m/min) exercise (INT), 2) twelve weeks of the intensive exercise followed by four weeks of moderate intensity (18 m/min) exercise (INT + MOD), 3) twelve weeks of the intensive exercise followed by four weeks of detraining (INT + DT), and 4) sedentary rats (SED). The exercise protocols were performed five days a week for one h/day. Echocardiography, real-time PCR, western blotting, and histological staining were performed at the end of week sixteen.

RESULTS

INT rats developed concentric hypertrophy without diastolic dysfunction compared to SED (p = 0.006) and INT + DT (p = 0.035). Wnt1, β-catenin and CyclinD1 proteins in the training groups were significantly higher than SED rats (p < 0.001). Interestingly, INT rats had higher protein levels than INT + DT and INT + MOD (p < 0.001), with higher gene expression compared to SED rats (p < 0.05). There was also a significant increase in collagen deposition in INT rats compared to SED (p = 0.046) and INT + DT (p = 0.034). Furthermore, INT + MOD and INT + DT rats did not show any adverse structural, functional, or histological changes.

CONCLUSIONS

Long-term intensive endurance training seems to be associated with increased collagen deposition and wall thickness in the RV through Wnt/β-catenin signaling (which is concentration dependent), without changes in diastolic function.

CLINICAL PERSPECTIVE

Over the past decades, there has been an ongoing debate about whether the structural and functional adaptations of the cardiovascular system in trained endurance athletes are benign physiological responses to training or potentially pathological changes related to disease. While the adaptations of the left heart are well-documented, the remodeling of the right heart remains a subject of discussion. To gain insights into the ability of sustained high-intensity exercise to cause adverse right ventricular (RV) remodeling, we conducted an experimental study in which male rats were trained to run vigorously for 1 h daily over a 16-week period and compared them to a parallel group of sedentary control rats. Our findings revealed that intense long-term exercise induced morphological changes along with fibrosis affecting the RV. These fibrotic changes were a result of the 16-week vigorous exercise training regimen. If these results are confirmed in humans, they suggest that prolonged high-intensity endurance exercise training may lead to adverse cardiac remodeling. Our findings have important potential implications for the assessment of cardiac remodeling in individuals engaged in high-level exercise training.

SDF-1-edited human amniotic mesenchymal stem cells stimulate angiogenesis in treating hindlimb ischaemia

Although stem cells have extensively been studied as a novel vehicle for tissue repair, their sustained efficacy remains controversial. In this study, we aimed to investigate the angiogenic potency over time of stromal cell‐derived factor‐1 (SDF‐1) gene‐edited amniotic mesenchymal stem cells (AMM/S) in a hindlimb ischaemia model. An SDF‐1 transgene was inserted into the AMM cell genome via transcription activator‐like effector nuclease (TALEN) mediated knock‐in, and cell migration, Matrigel tube formation, and in vivo Matrigel plug assays were performed. AMM/S were also transplanted into hindlimb ischaemia model mice. Blood perfusion, therapeutic potential, histology, capillary density and in vivo angiogenic assays were performed. AMM/S exhibited high expression of the SDF‐1 gene, and robustly promoted migration, proliferation and microvascular formation. AMM/S transplantation significantly increased blood perfusion and limb loss prevention compared with AMM. AMM/S also significantly inhibited increased capillary density and expression of angiogenic factors in the ischaemic hindlimb. Our study demonstrated that AMM/S provides a significant therapeutic effect in ischaemic hindlimbs by enhancing angiogenesis.

Influences of Long-Term Exercise and High-Fat Diet on Age-Related Telomere Shortening in Rats

(1) Obesity and exercise are believed to modify age-related telomere shortening by regulating telomerase and shelterins. Existing studies are inconsistent and limited to peripheral blood mononuclear cells (PBMCs) and selected solid tissues. (2) Female Sprague Dawley (SD) rats received either standard diet (ND) or high-fat diet (HFD). For 10 months, half of the animals from both diet groups performed 30 min running at 30 cm/s on five consecutive days followed by two days of rest (exeND, exeHFD). The remaining animals served as sedentary controls (coND, coHFD). Relative telomere length (RTL) and mRNA expression of telomerase (TERT) and the shelterins TERF-1 and TERF-2 were mapped in PBMCs and nine solid tissues. (3) At study end, coND and coHFD animals showed comparable RTL in most tissues with no systematic differences in TERT, TERF-1 and TERF-2 expression. Only visceral fat of coHFD animals showed reduced RTL and lower expression of TERT, TERF-1 and TERF-2. Exercise had heterogeneous effects on RTL in exeND and exeHFD animals with longer telomeres in aorta and large intestine, but shorter telomeres in PBMCs and liver. Telomere-regulating genes showed inconsistent expression patterns. (4) In conclusion, regular exercise or HFD cannot systematically modify RTL by regulating the expression of telomerase and shelterins.

Optimization of different intensities of exercise preconditioning in protecting exhausted exercise induced heart injury in rats

This study was to optimize the exercise preconditioning (EP) intensity in protecting from exhaustive exercise-induced cardiac injury (EECI). A total of 98 male Sprague-Dawley rats were divided into 7 groups (n ​= ​14): the control group (C), the exhaustive exercise group (EE) and the EP ​+ ​EE groups, which include the V10 (53.0%˙O_2max), V15 (58.4%˙O_2max), V20 (67.0%˙O_2max), V26 (74.0%˙O_2max) and V30 (80.0%˙O_2max) groups. Except the C group, the other groups were subjected to treadmill running. The serum contents of N terminal pro B type natriuretic peptide (NT-proBNP) and cardiac troponin I (cTn-I) were detected by the enzyme-linked immunosorbent assay method, ECG was recorded, heart function was detected by pressure volume catheter and the activities of mitochondrial electron transfer pathway (ET pathway) complexes I, Ⅱ and IV were measured by high-resolution respiration instrument. Compared to the EE group, the EP groups have shown decrease of NT-proBNP and cTn-I, improvement of mitochondrial respiratory function and cardiac function. Compared to other EP groups, the V26 group has shown significant decrease of myocardial enzymes and improvement of mitochondrial function. The correlation analysis showed the EP effect was proportional to EP intensity in the range of 53.0%˙O_2max-74.0%˙O_2max. High intensity and long duration of exhaustive exercise caused cardiac injury and EP could decrease serum level of NT-proBNP and cTn-I, improve electrical derangement and the left ventricular function, and raise the activities of ET pathway complexes I, Ⅱ and IV. The protection of EP on EECI was improved as the EP intensity was increased from 53.0%˙O_2max to 74.0%˙O_2max and when EP intensity was 74.0%˙O_2max, the effect was the most obvious among all the setting EP groups.

Potential Long-Term Health Problems Associated with Ultra-Endurance Running: A Narrative Review

It is well established that physical activity reduces all-cause mortality and can prolong life. Ultra-endurance running (UER) is an extreme sport that is becoming increasingly popular, and comprises running races above marathon distance, exceeding 6 h, and/or running fixed distances on multiple days. Serious acute adverse events are rare, but there is mounting evidence that UER may lead to long-term health problems. The purpose of this review is to present the current state of knowledge regarding the potential long-term health problems derived from UER, specifically potential maladaptation in key organ systems, including cardiovascular, respiratory, musculoskeletal, renal, immunological, gastrointestinal, neurological, and integumentary systems. Special consideration is given to youth, masters, and female athletes, all of whom may be more susceptible to certain long-term health issues. We present directions for future research into the pathophysiological mechanisms that underpin athlete susceptibility to long-term issues. Although all body systems can be affected by UER, one of the clearest effects of endurance exercise is on the cardiovascular system, including right ventricular dysfunction and potential increased risk of arrhythmias and hypertension. There is also evidence that rare cases of acute renal injury in UER could lead to progressive renal scarring and chronic kidney disease. There are limited data specific to female athletes, who may be at greater risk of certain UER-related health issues due to interactions between energy availability and sex-hormone concentrations. Indeed, failure to consider sex differences in the design of female-specific UER training programs may have a negative impact on athlete longevity. It is hoped that this review will inform risk stratification and stimulate further research about UER and the implications for long-term health.

The effects of long-term moderate exercise and Western-type diet on oxidative/nitrosative stress, serum lipids and cytokines in female Sprague Dawley rats

Purpose

Regular exercise reduces obesity and the risk of cardiovascular disease. However, health-promoting benefits of physical activity are commonly associated with increased inflammation and oxidative stress. Here, we tested whether constant moderate exercise is able to prevent or attenuate the oxidative/nitrosative stress, inflammation, and serum lipids in lean and obese rats.

Methods

Four-month-old female Sprague Dawley rats received standard or a high-fat diet. Animals were subjected to a physical activity protocol, consisting of 30 min forced treadmill exercise for 5 consecutive days per week during 10 months. Baseline and sedentary (non-exercised) rats were used as controls. Lipids, oxidized low-density lipoprotein cholesterol, nitric oxide metabolites, and pro- and anti-inflammatory markers were measured in blood collected upon euthanasia.

Results

At variance to young baseline control rats, 14-month-old animals fed normal diet had increased plasma lipid levels, including total cholesterol and triglycerides, which were further elevated in rats that consumed a high-fat diet. While treadmill exercise did not lower the amount of serum lipids in standard diet group, forced physical activity reduced non-high-density lipoprotein cholesterol in response to high-fat diet feeding. Exercised rats fed standard diet or high-fat diet had lower abundancy of nitric oxide metabolites, which coincided with increased levels of oxidized low-density lipoprotein cholesterol. Accordingly, the amount of nitric oxide metabolites correlated inversely with oxidized low-density lipoprotein cholesterol and homo-arginine. Exercise significantly reduced inflammatory cytokines in high-fat diet fed rats only.

Conclusion

Our study suggests that regular exercise alters the equilibrium between oxidative and anti-oxidative compounds and reduces pro-inflammatory cytokines.

Paraoxonase and oxidative stress changes in left and right ventricles of exhaustively exercised rats

Exhaustive exercise can cause subclinical inflammation to the heart, as it is an oxidative tissue that works continuously. The effect of exhaustive exercise on left and right ventricles (LVs, RVs) may be different. It is claimed that paraoxonase-1 (PON1), an antioxidant enzyme, has a cardioprotective effect on oxidative stress. Rats were separated as non-exercised controls (Con), those euthanized immediately after (E-0) and 24 h after exhaustive exercise (E-24). Cardiac troponin-I (cTnI), total antioxidant status (TAS), total oxidant status (TOS), PON1 activities, and histological findings in LV and RV of the exhausted rats were evaluated. TAS and PON1 levels were lower in LVs compared with RVs of all groups. TOS levels were high in LVs compared with RVs of all groups. In LVs, TAS levels decreased significantly in the E-0 group while PON1 activity decreased in E-0 and E-24 groups compared with controls. In LVs, TOS levels decreased significantly in E-0 and E-24 groups, but in RVs a decrease was seen only in the E-0 group. cTnI levels increased significantly in the E-0 group and decreased to control levels in the E-24 group. Considering the histological and biochemical findings, exhaustive exercise affected the heart to the maximum during and just after exhaustion, and LV was influenced more than RV.

The effects of endurance exercise on the heart: panacea or poison?

Regular aerobic physical exercise of moderate intensity is undeniably associated with improved health and increased longevity, with some studies suggesting that more is better. Endurance athletes exceed the usual recommendations for exercise by 15-fold to 20-fold. The need to sustain a large cardiac output for prolonged periods is associated with a 10-20% increase in left and right ventricular size and a substantial increase in left ventricular mass. A large proportion of endurance athletes have raised levels of cardiac biomarkers (troponins and B-type natriuretic peptide) and cardiac dysfunction for 24-48 h after events, but what is the relevance of these findings? In the longer term, some endurance athletes have an increased prevalence of coronary artery disease, myocardial fibrosis and arrhythmias. The inherent association between these 'maladaptations' and sudden cardiac death in the general population raises the question of whether endurance exercise could be detrimental for some individuals. However, despite speculation that these abnormalities confer an increased risk of future adverse events, elite endurance athletes have an increased life expectancy compared with the general population.

Exercise-Related Acute Cardiovascular Events and Potential Deleterious Adaptations Following Long-Term Exercise Training: Placing the Risks Into Perspective-An Update: A Scientific Statement From the American Heart Association

Epidemiological and biological plausibility studies support a cause-and-effect relationship between increased levels of physical activity or cardiorespiratory fitness and reduced coronary heart disease events. These data, plus the well-documented anti-aging effects of exercise, have likely contributed to the escalating numbers of adults who have embraced the notion that "more exercise is better." As a result, worldwide participation in endurance training, competitive long distance endurance events, and high-intensity interval training has increased markedly since the previous American Heart Association statement on exercise risk. On the other hand, vigorous physical activity, particularly when performed by unfit individuals, can acutely increase the risk of sudden cardiac death and acute myocardial infarction in susceptible people. Recent studies have also shown that large exercise volumes and vigorous intensities are both associated with potential cardiac maladaptations, including accelerated coronary artery calcification, exercise-induced cardiac biomarker release, myocardial fibrosis, and atrial fibrillation. The relationship between these maladaptive responses and physical activity often forms a U- or reverse J-shaped dose-response curve. This scientific statement discusses the cardiovascular and health implications for moderate to vigorous physical activity, as well as high-volume, high-intensity exercise regimens, based on current understanding of the associated risks and benefits. The goal is to provide healthcare professionals with updated information to advise patients on appropriate preparticipation screening and the benefits and risks of physical activity or physical exertion in varied environments and during competitive events.

Follistatin-like 1: A dual regulator that promotes cardiomyocyte proliferation and fibrosis

Follistatin-like 1 (FSTL1) is a key factor in maintaining cardiac growth and development. It can be activated by exercise training and has a dual role in promoting cardiomyocyte proliferation and fibrosis, but its underlying mechanism is not fully understood. To elucidate the dual mechanism and target of FSTL1 regulating of cardiomyocyte proliferation and myocardial fibrosis, and the mechanism by which exercise-regulated FSTL1 improves cardiovascular disease, we explored the signal transduction pathway of FSTL1 promoting cardiomyocyte proliferation and fibrosis, and compared the effects of different modes of exercise on the dual role of FSTL1. We believe that the dual role of promoting cardiomyocyte proliferation and fibrosis may be related to the ratio of cardiomyocyte and myocardial interstitial cell proliferation, different stages of the disease, different degrees of fibrosis, immune repair process, and transforming growth factor-β activation. Compared with long-term excessive endurance exercise, moderate resistance exercise can activate cardiomyocyte proliferation pathway through FSTL1, which is one of the effective ways to prevent cardiovascular disease.

Shikonin improve sepsis-induced lung injury via regulation of miRNA-140-5p/TLR4-a vitro and vivo study

Shikonin is an anti-inflammatory agent extracted from natural herbs. The aim of this study is to explain the treatment effects and mechanism of Shikonin in acute lung injury induced by sepsis. In this study, first, we evaluate different Shikonin concentrations for the anti-inflammation of acute lung injury induced by sepsis in an in vivo study. On the basis of the results, we confirm that 50.0 mg/kg was the best therapeutic Shikonin concentration. As a second step, we discuss the mechanism of Shikonin by a vitro cell experiment. Finaly, we validate that Shikonin has effective treatment effects on acute lung injury via regulation of microRNA-140-5p/toll-like receptor 4 (miRNA-140-5p/TLR4) in the in vivo study. The results of vitro and vivo study showed that Shikonin could improve acute lung injury induced by sepsis. The mechanism might be correlation miRNA-140-5p expression increasing, and regulated targeted gene TLR4, with TLR4 expression depressing, the downstream myeloid differentiation protein 88 and nuclear factor κB proteins expression were suppressed. In conclusion, Shikonin improved sepsis induced lung injury by regulation miRNA-140-5p/TLR4.

Generation of directly reprogrammed human endothelial cells derived from fibroblast using ultrasound

Physical microenvironment plays an important role in determining cellular reprogramming. In this study, we first generated directly reprogrammed human dermal fibroblasts (HDFs) into endothelial cells (ECs) mediated by environmental transition-guided cellular reprogramming (e/Entr) using ultrasound and characterized e/Entr. Ultrasound stimulus was introduced to ECs culture media and HDFs and induced into ECs-like cells. We performed microarray, RT-PCR, protein analysis, matrigel plug assay and e/Entr were transplanted into ischemic hindlimb mice model. Here we show that the activation of MAPK signaling pathways and the modulation of histone proteins such as Hp1-α, H3K27me3 and H3K4me3 in e/Entr contribute to the changes in chromatin configuration and reprogramming. Microarray data demonstrated that e/Entr highly expressed genes associated with ECs transcription factors and angiogenesis. In addition, the transplantation of e/Entr into hindlimb ischemia showed a high recovery of blood perfusion, limb salvage and e/Entr contributed to the formation of new vessels. In conclusion, the present study provided the first evidence that ultrasound reprogramming can induce postnatal cells to functional ECs. Therefore, our data suggest that physical stimulus-mediated reprogramming is a highly effective and safe strategy for the novel therapeutic alternatives.