Exercise Inhibits Doxorubicin-Induced Cardiotoxicity via Regulating B Cells.

BACKGROUND: Doxorubicin is an effective chemotherapeutic agent, but its use is limited by acute and chronic cardiotoxicity. Exercise training has been shown to protect against doxorubicin-induced cardiotoxicity, but the involvement of immune cells remains unclear. This study aimed to investigate the role of exercise-derived B cells in protecting against doxorubicin-induced cardiotoxicity and to further determine whether B cell activation and antibody secretion play a role in this protection. METHODS: Mice that were administered with doxorubicin (5 mg/kg per week, 20 mg/kg cumulative dose) received treadmill running exercise. The adoptive transfer of exercise-derived splenic B cells to µMT-/- (B cell-deficient) mice was performed to elucidate the mechanism of B cell regulation that mediated the effect of exercise. RESULTS: Doxorubicin-administered mice that had undergone exercise training showed improved cardiac function, and low levels of cardiac apoptosis, atrophy, and fibrosis, and had reduced cardiac antibody deposition and proinflammatory responses. Similarly, B cell pharmacological and genetic depletion alleviated doxorubicin-induced cardiotoxicity, which phenocopied the protection of exercise. In vitro performed coculture experiments confirmed that exercise-derived B cells reduced cardiomyocyte apoptosis and fibroblast activation compared with control B cells. Importantly, the protective effect of exercise on B cells was confirmed by the adoptive transfer of splenic B cells from exercised donor mice to µMT-/- recipient mice. However, blockage of Fc gamma receptor IIB function using B cell transplants from exercised Fc gamma receptor IIB-/- mice abolished the protection of exercise-derived B cells against doxorubicin-induced cardiotoxicity. Mechanistically, we found that Fc gamma receptor IIB, an important B cell inhibitory receptor, responded to exercise and increased B cell activation threshold, which participated in exercise-induced protection against doxorubicin-induced cardiotoxicity. CONCLUSIONS: Our results demonstrate that exercise training protects against doxorubicin-induced cardiotoxicity by upregulating Fc gamma receptor IIB expression in B cells, which plays an important anti-inflammatory role and participates in the protective effect of exercise against doxorubicin-induced cardiotoxicity.

Inhibition of Hmbox1 Promotes Cardiomyocyte Survival and Glucose Metabolism Through Gck Activation in Ischemia/Reperfusion Injury.

BACKGROUND: Exercise-induced physiological cardiac growth regulators may protect the heart from ischemia/reperfusion (I/R) injury. Homeobox-containing 1 (Hmbox1), a homeobox family member, has been identified as a putative transcriptional repressor and is downregulated in the exercised heart. However, its roles in exercise-induced physiological cardiac growth and its potential protective effects against cardiac I/R injury remain largely unexplored. METHODS: We studied the function of Hmbox1 in exercise-induced physiological cardiac growth in mice after 4 weeks of swimming exercise. Hmbox1 expression was then evaluated in human heart samples from deceased patients with myocardial infarction and in the animal cardiac I/R injury model. Its role in cardiac I/R injury was examined in mice with adeno-associated virus 9 (AAV9) vector-mediated Hmbox1 knockdown and in those with cardiac myocyte-specific Hmbox1 ablation. We performed RNA sequencing, promoter prediction, and binding assays and identified glucokinase (Gck) as a downstream effector of Hmbox1. The effects of Hmbox1 together with Gck were examined in cardiomyocytes to evaluate their cell size, proliferation, apoptosis, mitochondrial respiration, and glycolysis. The function of upstream regulator of Hmbox1, ETS1, was investigated through ETS1 overexpression in cardiac I/R mice in vivo. RESULTS: We demonstrated that Hmbox1 downregulation was required for exercise-induced physiological cardiac growth. Inhibition of Hmbox1 increased cardiomyocyte size in isolated neonatal rat cardiomyocytes and human embryonic stem cell-derived cardiomyocytes but did not affect cardiomyocyte proliferation. Under pathological conditions, Hmbox1 was upregulated in both human and animal postinfarct cardiac tissues. Furthermore, both cardiac myocyte-specific Hmbox1 knockout and AAV9-mediated Hmbox1 knockdown protected against cardiac I/R injury and heart failure. Therapeutic effects were observed when sh-Hmbox1 AAV9 was administered after I/R injury. Inhibition of Hmbox1 activated the Akt/mTOR/P70S6K pathway and transcriptionally upregulated Gck, leading to reduced apoptosis and improved mitochondrial respiration and glycolysis in cardiomyocytes. ETS1 functioned as an upstream negative regulator of Hmbox1 transcription, and its overexpression was protective against cardiac I/R injury. CONCLUSIONS: Our studies unravel a new role for the transcriptional repressor Hmbox1 in exercise-induced physiological cardiac growth. They also highlight the therapeutic potential of targeting Hmbox1 to improve myocardial survival and glucose metabolism after I/R injury.

Collaborative CRISPR-Cas System-Enabled Detection of Circulating Circular RNA for Reliable Monitoring of Acute Myocardial Infarction.

Acute myocardial infarction (AMI) is one of the major causes of death worldwide, posing significant global health challenges. Circular RNA (circRNA) has recently emerged as a potential diagnostic biomarker for AMI, providing valuable information for timely medical care. In this work, a new electrochemical method for circRNA detection by engineering a collaborative CRISPR-Cas system is developed. This system integrates the unique circRNA-targeting ability with cascade trans-cleavage activities of Cas effectors, using an isothermal primer exchange reaction as the bridge. Using cZNF292, a circulating circRNA biomarker for AMI is identified by this group; as a model, the collaborative CRISPR-Cas system-based method exhibits excellent accuracy and sensitivity with a low detection limit of 2.13 × 10-15 m. Moreover, the method demonstrates a good diagnostic performance for AMI when analyzing whole blood samples. Therefore, the method may provide new insight into the detection of circRNA biomarkers and is expected to have great potential in AMI diagnosis in the future.

miR-486 attenuates cardiac ischemia/reperfusion injury and mediates the beneficial effect of exercise for myocardial protection.

Exercise and its regulated molecules have myocardial protective effects against cardiac ischemia/reperfusion (I/R) injury. The muscle-enriched miR-486 was previously identified to be upregulated in the exercised heart, which prompted us to investigate the functional roles of miR-486 in cardiac I/R injury and to further explore its potential in contributing to exercise-induced protection against I/R injury. Our data showed that miR-486 was significantly downregulated in the heart upon cardiac I/R injury. Both preventive and therapeutic interventions of adeno-associated virus 9 (AAV9)-mediated miR-486 overexpression could reduce cardiac I/R injury. Using AAV9 expressing miR-486 with a cTnT promoter, we further demonstrated that cardiac muscle cell-targeted miR-486 overexpression was also sufficient to protect against cardiac I/R injury. Consistently, miR-486 was downregulated in oxygen-glucose deprivation/reperfusion (OGDR)-stressed cardiomyocytes, while upregulating miR-486 inhibited cardiomyocyte apoptosis through PTEN and FoxO1 inhibition and AKT/mTOR activation. Finally, we observed that miR-486 was necessary for exercise-induced protection against cardiac I/R injury. In conclusion, miR-486 is protective against cardiac I/R injury and myocardial apoptosis through targeting of PTEN and FoxO1 and activation of the AKT/mTOR pathway, and mediates the beneficial effect of exercise for myocardial protection. Increasing miR-486 might be a promising therapeutic strategy for myocardial protection.

Long Noncoding RNA Cardiac Physiological Hypertrophy-Associated Regulator Induces Cardiac Physiological Hypertrophy and Promotes Functional Recovery After Myocardial Ischemia-Reperfusion Injury.

BACKGROUND: The benefits of exercise training in the cardiovascular system have been well accepted; however, the underlying mechanism remains to be explored. Here, we report the initial functional characterization of an exercise-induced cardiac physiological hypertrophy-associated novel long noncoding RNA (lncRNA). METHODS: Using lncRNA microarray profiling, we identified lncRNAs in contributing the modulation of exercise-induced cardiac growth that we termed cardiac physiological hypertrophy-associated regulator (CPhar). Mice with adeno-associated virus serotype 9 driving CPhar overexpression and knockdown were used in in vivo experiments. Swim training was used to induce physiological cardiac hypertrophy in mice, and ischemia reperfusion injury surgery was conducted to investigate the protective effects of CPhar in mice. To investigate the mechanisms of CPhar's function, we performed various analyses including quantitative reverse transcription polymerase chain reaction, Western blot, histology, cardiac function (by echocardiography), functional rescue experiments, mass spectrometry, in vitro RNA transcription, RNA pulldown, RNA immunoprecipitation, chromatin immunoprecipitation assay, luciferase reporter assay, and coimmunoprecipitation assays. RESULTS: We screened the lncRNAs in contributing the modulation of exercise-induced cardiac growth through lncRNA microarray profiling and found that CPhar was increased with exercise and was necessary for exercise-induced physiological cardiac growth. The gain and loss of function of CPhar regulated the expression of proliferation markers, hypertrophy, and apoptosis in cultured neonatal mouse cardiomyocytes. Overexpression of CPhar prevented myocardial ischemia reperfusion injury and cardiac dysfunction in vivo. We identified DDX17 (DEAD-Box Helicase 17) as a binding partner of CPhar in regulating CPhar downstream factor ATF7 (activating transcription factor 7) by sequestering C/EBPß (CCAAT/enhancer binding protein beta). CONCLUSIONS: Our study of this lncRNA CPhar provides new insights into the regulation of exercise-induced cardiac physiological growth, demonstrating the cardioprotective role of CPhar in the heart, and expanding our mechanistic understanding of lncRNA function, as well.

Cathelicidin-related antimicrobial peptide protects against myocardial ischemia/reperfusion injury.

BACKGROUND: Cathelicidins are a major group of natural antimicrobial peptides which play essential roles in regulating host defense and immunity. In addition to the antimicrobial and immunomodulatory activities, recent studies have reported the involvement of cathelicidins in cardiovascular diseases by regulating inflammatory response and microvascular dysfunction. However, the role of cathelicidins in myocardial apoptosis upon cardiac ischemia/reperfusion (I/R) injury remains largely unknown. METHODS: CRAMP (cathelicidin-related antimicrobial peptide) levels were measured in the heart and serum from I/R mice and in neonatal mouse cardiomyocytes treated with oxygen glucose deprivation/reperfusion (OGDR). Human serum cathelicidin antimicrobial peptide (LL-37) levels were measured in myocardial infarction (MI) patients. The role of CRAMP in myocardial apoptosis upon I/R injury was investigated in mice injected with the CRAMP peptide and in CRAMP knockout (KO) mice, as well as in OGDR-treated cardiomyocytes. RESULTS: We observed reduced CRAMP level in both heart and serum samples from I/R mice and in OGDR-treated cardiomyocytes, as well as reduced LL-37 level in MI patients. Knockdown of CRAMP enhanced cardiomyocyte apoptosis, and CRAMP KO mice displayed increased infarct size and myocardial apoptosis. In contrast, the CRAMP peptide reduced cardiomyocyte apoptosis and I/R injury. The CRAMP peptide inhibited cardiomyocyte apoptosis by activation of Akt and ERK1/2 and phosphorylation and nuclear export of FoxO3a. c-Jun was identified as a negative regulator of the CRAMP gene. Moreover, lower level of serum LL-37/neutrophil ratio was associated with readmission and/or death in MI patients during 1-year follow-up. CONCLUSIONS: CRAMP protects against cardiomyocyte apoptosis and cardiac I/R injury via activation of Akt and ERK and phosphorylation and nuclear export of FoxO3a. Increasing LL-37 might be a novel therapy for cardiac ischemic injury.

Correction to: Exercise-induced circulating extracellular vesicles protect against cardiac ischemia-reperfusion injury.

The original version of this article unfortunately contained a mistake.

miR-21 suppression prevents cardiac alterations induced by d-galactose and doxorubicin.

d-galactose (d-gal)-induced cardiac alterations and Doxorubicin (Dox)-induced cardiomyocyte senescence are commonly used models to study cardiac aging. Accumulating evidence has suggested that microRNAs (miRNAs, miRs) are critically involved in the regulation of cellular and organismal aging and age-related diseases. However, little has been revealed about the roles of miRNAs in cardiac alterations induced by d-gal and Dox. In this study, we used miRNA arrays to investigate the dysregulated miRNAs in heart samples from 15month-old versus 2month-old male C57BL/6 mice and further validated them in d-gal-induced pseudo-aging mouse model and Dox-induced cardiomyocyte senescence in vitro model. We confirmed a significant increase of miR-21 in all these models by quantitative reverse transcription polymerase chain reactions. We further demonstrated that miR-21 was able to promote Dox-induced cardiomyocyte senescence whereas suppression of miR-21 could prevent that, as determined by percentage of ß-gal-positive cells and gene markers of aging. Phosphatase and tensin homolog (PTEN) was identified as a target gene of miR-21, mediating its effect in increasing cardiomyocyte senescence. Finally, we found that miR-21 knockout mice were resistant to d-gal-induced alterations in aging-markers and cardiac function. Collectively, this study provides direct evidence that inhibition of miR-21 is protective against d-gal-induced cardiac alterations and Dox-induced cardiomyocyte senescence via targeting PTEN. Inhibition of miR-21 might be a novel strategy to combat cardiac aging.

Telocytes in cardiac regeneration and repair.

Telocytes (TCs) are a novel type of stromal cells reported by Popescu's group in 2010. The unique feature that distinguishes TCs from other "classical" stromal cells is their extremely long and thin telopodes (Tps). As evidenced by electron microscopy, TCs are widely distributed in almost all tissues and organs. TCs contribute to form a three-dimensional interstitial network and play as active regulators in intercellular communication via homocellular/heterocellular junctions or shed vesicles. Interestingly, increasing evidence suggests the potential role of TCs in regenerative medicine. Although the heart retains some limited endogenous regenerative capacity, cardiac regenerative and repair response is however insufficient to make up the loss of cardiomyocytes upon injury. Developing novel strategies to increase cardiomyocyte renewal and repair is of great importance for the treatment of cardiac diseases. In this review, we focus on the role of TCs in cardiac regeneration and repair. We particularly describe the intercellular communication between TCs and cardiomyocytes, stem/progenitor cells, endothelial cells, and fibroblasts. Also, we discuss the current knowledge about TCs in cardiac repair after myocardial injury, as well as their potential roles in cardiac development and aging. TC-based therapy or TC-derived exosome delivery might be used as novel therapeutic strategies to promote cardiac regeneration and repair.

Cardiovascular medicine in China: what can we do to achieve the Healthy China 2030 plan?

Cardiovascular diseases (CVDs) represent the leading cause of death in China. The Chinese government approved the Healthy China 2030 plan (jiànkang zhongguó 2030), emphasizing the strategic role of health in China's development. As morbidity and mortality from CVDs are constantly increasing in China, the prevention and treatment of CVDs are vital to achieve this plan. Following the major principles of health priority, science and technology innovation, scientific development, and balanced medical resource allocation outlined in the Healthy China 2030 plan, this Commentary briefly introduces the current status of CVDs in China and marks the important events undertaken to achieve this plan.

Circular RNAs as Novel Biomarkers for Cardiovascular Diseases.

Cardiovascular diseases are among the most serious diseases, which are a leading cause of death across the world. Early diagnosis and prognosis prediction are keys for treatment and reduction of death rates. Circular RNAs (circRNAs) play a critical role in the physiology and pathology of biological system and participate in the development of diseases. In addition, circRNAs are relative stable and abundant. Therefore, many studies have suggested that circRNAs could be used as biomarkers for diseases, such as neurological diseases, cancers, immune diseases, and digestive diseases. Here we summarize recent studies on circRNAs and compare the characteristics of circRNAs with traditional biomarkers. Finally, we highlight the value of circRNAs as potential biomarkers for cardiovascular diseases, including acute myocardial infarction, heart failure, coronary artery disease, and hypertension. In conclusion, circRNAs may be promising biomarkers for cardiovascular diseases.

Cardiac cell proliferation is not necessary for exercise-induced cardiac growth but required for its protection against ischaemia/reperfusion injury.

The adult heart retains a limited ability to regenerate in response to injury. Although exercise can reduce cardiac ischaemia/reperfusion (I/R) injury, the relative contribution of cardiac cell proliferation including newly formed cardiomyocytes remains unclear. A 4-week swimming murine model was utilized to induce cardiac physiological growth. Simultaneously, the antineoplastic agent 5-fluorouracil (5-FU), which acts during the S phase of the cell cycle, was given to mice via intraperitoneal injections. Using EdU and Ki-67 immunolabelling, we showed that exercise-induced cardiac cell proliferation was blunted by 5-FU. In addition, the growth of heart in size and weight upon exercise was unaltered, probably due to the fact that exercise-induced cardiomyocyte hypertrophy was not influenced by 5-FU as demonstrated by wheat germ agglutinin staining. Meanwhile, the markers for pathological hypertrophy, including ANP and BNP, were not changed by either exercise or 5-FU, indicating that physiological growth still developed in the presence of 5-FU. Furthermore, we showed that CITED4, a key regulator for cardiomyocyte proliferation, was blocked by 5-FU. Meanwhile, C/EBPß, a transcription factor responsible for both cellular proliferation and hypertrophy, was not altered by treatment with 5-FU. Importantly, the effects of exercise in reducing cardiac I/R injury could be abolished when cardiac cell proliferation was attenuated in mice treated with 5-FU. In conclusion, cardiac cell proliferation is not necessary for exercise-induced cardiac physiological growth, but it is required for exercise-associated protection against I/R injury.

Long Non-Coding RNAs in Cardiac Remodeling.

Cardiac remodeling occurs after stress to the heart, manifested as pathological processes, including hypertrophy and apoptosis of cardiomyocytes, dysfunction of vascular endothelial cells and vascular smooth muscle cells as well as differentiation and proliferation of fibroblasts, ultimately resulting in progression of cardiovascular diseases. Emerging evidence has revealed that long non-coding RNAs (lncRNAs) acted as powerful and dynamic modifiers of cardiac remodeling. LncRNAs including Chaer, Chast, Mhrt, CHRF, ROR, H19, and MIAT have been implicated in cardiac hypertrophy while NRF, H19, APF, CARL, UCA, Mhrt and several other lncRNAs (n379599, n379519, n384640, n380433 and n410105) in cardiomyocyte loss and extracellular matrix remodeling. In addition, MALAT1 and TGFB2-OT1 have been reported to contribute to vascular endothelial cells dysfunction while lincRNA-p21 and lnc-Ang362 to vascular smooth muscle cells proliferation. Thus, manipulation of lncRNA expression levels through either the inhibition of disease-up-regulated lncRNAs or increasing disease-down-regulated lncRNAs represents novel therapeutic strategies for cardiac remodeling.

MicroRNA-222 Promotes the Proliferation of Pulmonary Arterial Smooth Muscle Cells by Targeting P27 and TIMP3.

BACKGROUND/AIMS: Aberrant vascular smooth muscle cell (VSMC) proliferation plays an important role in the development of pulmonary artery hypertension (PAH). Dysregulated microRNAs (miRNAs, miRs) have been implicated in the progression of PAH. miR-222 has a pro-proliferation effect on VSMCs while it has an anti-proliferation effect on vascular endothelial cells (ECs). As the biological function of a single miRNA could be cell-type specific, the role of miR-222 in pulmonary artery smooth muscle cell (PASMC) proliferation is not clear and deserves to be explored. METHODS: PASMCs were transfected with miR-222 mimic or inhibitor and PASMC proliferation was determined by Western blot for PCNA, Ki-67 and EdU staining, and cell number counting. The target genes of miR-222 including P27 and TIMP3 were determined by luciferase assay and Western blot. In addition, the functional rescue experiments were performed based on miR-222 inhibitor and siRNAs to target genes. RESULTS: miR-222 mimic promoted PASMC proliferation while miR-222 inhibitor decreased that. TIMP3 was identified to be a direct target gene of miR-222 based on luciferase assay. Meanwhile, P27 and TIMP3 were up-regulated by miR-222 inhibitor and down-regulated by miR-222 mimic. Moreover, P27 siRNA and TIMP3 siRNA could both attenuate the anti-proliferation effect of miR-222 inhibitor in PASMCs, supporting that P27 and TIMP3 are at least partially responsible for the regulatory effect of miR-222 in PASMCs. CONCLUSION: miR-222 promotes PASMC proliferation at least partially through targeting P27 and TIMP3.

Qiliqiangxin Attenuates Adverse Cardiac Remodeling after Myocardial Infarction in Ovariectomized Mice via Activation of PPARγ.

BACKGROUND/AIMS: This study was designed to investigate the therapeutic effect of traditional Chinese medication Qiliqiangxin (QLQX) on adverse cardiac remodeling after myocardial infarction (MI) in bilateral ovariectomized (OVX) female mice. METHODS: Eight-week old female C57BL/6 mice were operated to ligate the left anterior descending coronary artery seven days after bilateral ovariectomy and were orally administered either QLQX or vehicle. 21 days after ligation, echocardiography was performed to evaluate the heart function of all mice. Masson's Trichrome staining was applied to evaluate myocardial fibrosis. Collagen deposition was determined by the mRNA level of Collagen I, Collagen III and α-SMA using real-time quantitative polymerase chain reaction (qPCR). Myocardial apoptosis was examined by the protein level of Bax, Bcl2 and the Bcl2/Bax ratio using western blotting. RESULTS: These mice displayed a significant reduction in heart function, increased myocardial fibrosis and apoptosis, and decreased expression of peroxisome proliferator activated receptor γ (PPARγ) in the heart tissue, which could be reversed by QLQX treatment. Inhibition of PPAR reduced QLQX-mediated cardio-protective effects, while PPARγ activation did not further enhance the beneficial effect of QLQX. Furthermore, QLQX upregulated 9 genes (Cd36, Fatp, Pdk4, Acadm, Acadl, Acadvl, Cpt1a, Cpt1b and Cpt2) facilitating energy metabolism in the MI hearts of the OVX mice and 5 (Acadm, Acadl, Cpt1a, Cpt1b, Cpt2) of the 9 genes were the downstream targets of PPARγ. CONCLUSION: The present study indicates that QLQX has a treatment effect on pathological remodeling post MI in bilateral OVX female mice via activation of PPARγ, suggesting that QLQX may be a promising prescription for the treatment of postmenopausal women suffering from MI.

Circulating miR-30d Predicts Survival in Patients with Acute Heart Failure.

BACKGROUND/AIMS: Identification of novel biomarkers to identify acute heart failure (AHF) patients at high risk of mortality is an area of unmet clinical need. Recently, we reported that the baseline level of circulating miR-30d was associated with left ventricular remodeling in response to cardiac resynchronization therapy in advanced chronic heart failure patients. However, the role of circulating miR-30d as a prognostic marker of survival in patients with AHF has not been explored. METHODS: Patients clinically diagnosed with AHF were enrolled and followed up for 1 year. Quantitative reverse transcription polymerase chain reactions were used to determine serum miR-30d levels. The univariate logistic regression analysis and multivariate logistic regression analysis were used to determine the predictors for all-cause mortality in AHF patients. Kaplan-Meier survival analysis was used to analyze the role of miR-30d in prediction of survival. RESULTS: A total of 96 AHF patients were enrolled and followed up for 1 year. Serum miR-30d was significantly lower in AHF patients who expired in the one year follow-up period compared to those who survived. Univariate logistic regression analysis yielded 18 variables that were associated with all-cause mortality in AHF patients, while the multivariate logistic regression analysis identified 4 variables including heart rate, hemoglobin, serum sodium, and serum miR-30d level associated with mortality. ROC curve analysis showed that hemoglobin, heart rate and serum sodium displayed poor prognostic value for AHF (AUCs not higher than 0.700) compared to miR-30d level (AUC = 0.806). Kaplan-Meier survival analysis confirmed that patients with higher serum miR-30d levels had significantly lower mortality (P=0.001). CONCLUSION: In conclusion, this study shows evidence for the predictive value of circulating miR-30d as 1-year all-cause mortality in AHF patients. Large multicentre studies are further needed to validate our findings and accelerate the transition to clinical utilization.

Serum Irisin Predicts Mortality Risk in Acute Heart Failure Patients.

BACKGROUND/AIMS: Irisin is a peptide hormone cleaved from a plasma membrane protein fibronectin type III domain containing protein 5 (FNDC5). Emerging studies have indicated association between serum irisin and many major chronic diseases including cardiovascular diseases. However, the role of serum irisin as a predictor for mortality risk in acute heart failure (AHF) patients is not clear. METHODS: AHF patients were enrolled and serum was collected at the admission and all patients were followed up for 1 year. Enzyme-linked immunosorbent assay was used to measure serum irisin levels. To explore predictors for AHF mortality, the univariate and multivariate logistic regression analysis, and receiver-operator characteristic (ROC) curve analysis were used. To determine the role of serum irisin levels in predicting survival, Kaplan-Meier survival analysis was used. RESULTS: In this study, 161 AHF patients were enrolled and serum irisin level was found to be significantly higher in patients deceased in 1-year follow-up. The univariate logistic regression analysis identified 18 variables associated with all-cause mortality in AHF patients, while the multivariate logistic regression analysis identified 2 variables namely blood urea nitrogen and serum irisin. ROC curve analysis indicated that blood urea nitrogen and the most commonly used biomarker, NT-pro-BNP, displayed poor prognostic value for AHF (AUCs ≤ 0.700) compared to serum irisin (AUC = 0.753). Kaplan-Meier survival analysis demonstrated that AHF patients with higher serum irisin had significantly higher mortality (P<0.001). CONCLUSION: Collectively, our study identified serum irisin as a predictive biomarker for 1-year all-cause mortality in AHF patients though large multicenter studies are highly needed.

Exercise-induced circulating extracellular vesicles protect against cardiac ischemia-reperfusion injury.

Extracellular vesicles (EVs) serve an important function as mediators of intercellular communication. Exercise is protective for the heart, although the signaling mechanisms that mediate this cardioprotection have not been fully elucidated. Here using nano-flow cytometry, we found a rapid increase in plasma EVs in human subjects undergoing exercise stress testing. We subsequently identified that serum EVs were increased by ~1.85-fold in mice after 3-week swimming. Intramyocardial injection of equivalent quantities of EVs from exercised mice and non-exercised controls provided similar protective effects against acute ischemia/reperfusion (I/R) injury in mice. However, injection of exercise-induced EVs in a quantity equivalent to the increase seen with exercise (1.85 swim group) significantly enhanced the protective effect. Similarly, treatment with exercise-induced increased EVs provided additional anti-apoptotic effect in H2O2-treated H9C2 cardiomyocytes mediated by the activation of ERK1/2 and HSP27 signaling. Finally, by treating H9C2 cells with insulin-like growth factor-1 to mimic exercise stimulus in vitro, we found an increased release of EVs from cardiomyocytes associated with ALIX and RAB35 activation. Collectively, our results show that exercise-induced increase in circulating EVs enhances the protective effects of endogenous EVs against cardiac I/R injury. Exercise-derived EVs might serve as a potent therapy for myocardial injury in the future.

Traditional Chinese Medication Qiliqiangxin Protects Against Cardiac Remodeling and Dysfunction in Spontaneously Hypertensive Rats.

Qiliqiangxin (QLQX), a traditional Chinese herbs medication, exerted protective effect in chronic heart failure patients in a multicenter randomized double-blind study. QLQX has also been found to improve cardiac function and reduce cardiac fibrosis in spontaneously hypertension animal model. However, the effect of longterm treatment with QLQX in such a condition and the related molecular mechanisms remain largely unknown. In the present study, thirteen-week-old spontaneously hypertensive rats (SHRs) were treated by daily intragastric administration of QLQX or saline for one year. Echocardiography, electron microscopy, and Masson's trichrome staining were used to determine cardiac function, mitochondria ultrastructure, and cardiac fibrosis, respectively. Quantitative reverse transcription polymerase chain reactions (qRT-PCRs) and Western blotting were used to determine gene expressions. We found that QLQX significantly improved cardiac function and reduced gene markers of pathological hypertrophy including ANP, BNP, and Myh7. QLQX also attenuated cardiac fibrosis and apoptosis in SHRs as evidenced by downregulation of α-SMA, collagen I, collagen III, and TGF-ß expressions and reduction of Bax to Bcl-2 ratio. Moreover, the damage of mitochondrial ultrastructure was greatly improved and the reduction of PPAR-α, PPAR-γ, and PGC-1α expression levels was significantly restored in SHRs by treatment with QLQX. In conclusion, longterm treatment with QLQX protects against cardiac remodeling and dysfunction in hypertension by increasing PPARs and PGC-1α.

MicroRNAs Mediate Beneficial Effects of Exercise in Heart.

MicroRNAs (miRNAs, miRs), a group of small non-coding RNAs, repress gene expressions at posttranscriptional level in most cases and are involved in cardiovascular physiology and disease pathogenesis. Increasing evidence has proved that miRNAs are potential regulators of exercise induced cardiac growth and mediate the benefits of exercise in a variety of cardiovascular diseases. In this chapter, we will review the regulatory effects of miRNAs in cardiac adaptations to exercise, and summarize their cardioprotective effects against myocardial infarction, ischemia/reperfusion injury, heart failure, diabetic cardiomyopathy, atherosclerosis, hypertension, and pulmonary hypertension. Also, we will introduce circulating miRNAs in response to acute and chronic exercise. Therefore, miRNAs may serve as novel therapeutic targets and potential biomarkers for cardiovascular diseases.