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Background: Dysregulated metabolism of bioactive sphingolipids, including ceramides and sphingosine-1-phosphate, has been implicated in cardiovascular disease, although the specific species, disease contexts, and cellular roles are not completely understood. Sphingolipids are produced by the serine palmitoyltransferase enzyme, canonically composed of 2 subunits, SPTLC1 (serine palmitoyltransferase long chain base subunit 1) and SPTLC2 (serine palmitoyltransferase long chain base subunit 2). Noncanonical sphingolipids are produced by a more recently described subunit, SPTLC3 (serine palmitoyltransferase long chain base subunit 3)., Methods: The noncanonical (d16) and canonical (d18) sphingolipidome profiles in cardiac tissues of patients with end-stage ischemic cardiomyopathy and in mice with ischemic cardiomyopathy were analyzed by targeted lipidomics. Regulation of SPTLC3 by HIF1α under ischemic conditions was determined with chromatin immunoprecipitation. Transcriptomics, lipidomics, metabolomics, echocardiography, mitochondrial electron transport chain, mitochondrial membrane fluidity, and mitochondrial membrane potential were assessed in the cSPTLC3 KO transgenic mice we generated. Furthermore, morphological and functional studies were performed on cSPTLC3 KO mice subjected to permanent nonreperfused myocardial infarction., Results: Herein, we report that SPTLC3 is induced in both human and mouse models of ischemic cardiomyopathy and leads to production of atypical sphingolipids bearing 16-carbon sphingoid bases, resulting in broad changes in cell sphingolipid composition. This induction is in part attributable to transcriptional regulation by HIF1α under ischemic conditions. Furthermore, cardiomyocyte-specific depletion of SPTLC3 in mice attenuates oxidative stress, fibrosis, and hypertrophy in chronic ischemia, and mice demonstrate improved cardiac function and increased survival along with increased ketone and glucose substrate metabolism utilization. Depletion of SPTLC3 mechanistically alters the membrane environment and subunit composition of mitochondrial complex I of the electron transport chain, decreasing its activity., Conclusions: Our findings suggest a novel essential role for SPTLC3 in electron transport chain function and a contribution to ischemic injury by regulating complex I activity., Competing Interests: None.

Background: Hypertension is a risk factor for experiencing left ventricular ejection fraction (LVEF) declines during receipt of potentially cardiotoxic breast cancer (BC) treatment. We sought to determine whether the hypertension stage is associated with LVEF decline during BC treatment., Methods: Across 24 centers, cardiac magnetic resonance measures of LVEF and brachial arterial blood pressure (BP) measurements were performed in women with stages I to III BC before and 3 months after initiating potentially cardiotoxic chemotherapy. Using multivariable analysis, we assessed in a blinded fashion the association between 3-month ΔLVEF and precancer treatment American Heart Association/American College of Cardiology stages of hypertension., Results: Among 204 women, age averaged 56±1 years with 75% being White and 20% of Black race. Participants received anthracycline (45.6%), trastuzumab (22.5%), cyclophosphamide (52.9%), or paclitaxel (50%). After accounting for pretreatment LVEF, diabetes status, tobacco use, age, the number of antihypertensive medications, and body mass index, those with stage II hypertension experienced an LVEF decline of -2.89% ([95% CI, -0.69% to -5.19%]; P =0.01) relative to individuals with normal BP. Other stages saw nonsignificant declines relative to normal BP to elevated BP (-1.63% [95% CI, -0.62% to 3.88%]; P =0.16) and stage I hypertension (-0.94% [95% CI, -0.90% to 2.78%]; P =0.32)., Conclusions: Compared with women receiving treatment for BC with normal BP, there is a stronger association of decline in LVEF in women with stage II hypertension relative to women with other hypertension stages. This raises the possibility that stage along with hypertension presence may be associated with an increased risk for the LVEF decline among women receiving potentially cardiotoxic chemotherapy for BC., Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT02791581 and NCT01719562., Competing Interests: Disclosures None.

Background: Literature suggests a bidirectional association between advanced hepatic fibrosis (AHF) and coronary artery disease (CAD). We evaluated the association of AHF with immune activation, systemic inflammation, and adverse outcomes in patients with CAD., Methods and Results: A fibrosis-4 index cutoff value ≥2.67 was used to define AHF. Circulating levels of soluble urokinase plasminogen activator receptor and hsCRP (high-sensitivity C-reactive protein) were measured as markers for immune activation and systemic inflammation, respectively. The relationship of AHF with soluble urokinase plasminogen activator receptor, hsCRP, and adverse cardiovascular outcomes was evaluated. Among 3406 participants with CAD, 479 had AHF. Participants with AHF were older; were less likely to be Black individuals; and had a lower body mass index, worse renal function, and a prior history of heart failure. In multivariable linear regression models adjusted for clinical and demographic confounders, participants with AHF had 15.6% higher soluble urokinase plasminogen activator receptor and 24.0% higher hsCRP levels. They were more likely to experience the following adverse outcomes: all-cause death (adjusted hazard ratio [HR], 1.57 ([95% CI, 1.29-1.92]; P <0.001) and cardiovascular death: (subdistribution HR, 1.50 [95% CI, 1.14-1.95]; P =0.003). Mediation analysis showed that 47.0% (95% CI, 13.6%-81.2%]; P =0.006) of the indirect effect of AHF on cardiovascular death was mediated by circulating soluble urokinase plasminogen activator receptor levels., Conclusions: AHF is independently associated with immune activation, systemic inflammation, and adverse cardiovascular outcomes in patients with CAD. The association of AHF with adverse outcomes is partly mediated by immune activation, and targeting this pathway may help reduce the residual risk in patients with CAD.

Nonalcoholic fatty liver disease (NAFLD) is associated with atherogenic dyslipidemia and an increased risk of cardiovascular events. Previous studies have suggested an inverse relationship between NAFLD severity and lipoprotein(a) [Lp(a)] level, but contemporary data from the U.S. are lacking. Lp(a), lipid profile, apolipoproteins, and nuclear magnetic resonance-based lipoprotein particle concentrations were measured in 151 patients with biopsy-proven NAFLD. Levels were compared between those with nonalcoholic fatty liver (NAFL) on histology and non-alcoholic steatohepatitis (NASH). Median age was 55 [48, 62] years, 67% of patients were women, 83% were White, 43% had NAFL, and 57% had NASH. Triglyceride level was higher and high-density lipoprotein-cholesterol (HDL-C) was lower among those with NASH as compared with NAFL. Circulating apolipoprotein-B (ApoB) and low-density lipoprotein particle concentration (LDL-P) were 9% and 17% higher in the NASH group as compared with NAFL, respectively. Contrastingly, Lp(a) concentration was 50% lower in NASH relative to NAFL group. Hepatocyte ballooning, lobular inflammation, and fibrosis on histology were inversely associated with Lp(a) concentration. NAFLD severity has a discordant association with Lp(a) and other markers of atherogenic dyslipidemia. This relationship may have implications for prognosticating cardiovascular disease risk in patients with NAFLD., (Copyright © 2023. Published by Elsevier Inc.)

Background: Cancer therapies induce cardiac injury and increase cardiovascular disease (CVD) risk. In non-cancer populations, higher diet quality is associated with protection against CVD, but the relationship between diet and cardiac function in cancer survivors is unknown., Methods: This cross-sectional analysis from the Multi-Ethnic Study of Atherosclerosis (MESA) cohort included 113 cancer survivors (55 breast, 53 prostate, three lung, and three blood) and 4233 non-cancer controls. Dietary intake was reported via validated food frequency questionnaire. Alternate healthy eating index (AHEI) was calculated as a measure of quality. Cardiac function, determined as left ventricular ejection fraction (LVEF), was assessed by cardiac magnetic resonance., Results: Cancer survivors had a lower LVEF compared to controls (61.3 ± 6.5% v 62.4 ± 6.1%, p = 0.04). In all participants, total fat (β ± SE: -0.04 ± 0.01, p = 0.004), saturated fat (-0.11 ± 0.03, p < 0.001), and trans-fat (-0.36 ± 0.12, p = 0.002) intake were inversely associated with LVEF while AHEI (0.03 ± 0.01, p < 0.001) was positively associated with LVEF. Among cancer survivors only, sucrose intake was negatively related to LVEF (-0.15 ± 0.06, p = 0.02), and the ratio of unsaturated fat to saturated fat (2.7 ± 1.1, p = 0.01) and fiber intake (0.42 ± 0.14, p = 0.003) were positively related to LVEF., Discussion: In cancer survivors, improved dietary fat and carbohydrate quality (i.e., greater consumption of unsaturated fatty acids and fiber) was associated with favorable cardiac function, while higher sucrose was associated with worse cardiac function. Further research is needed to confirm these findings and test whether changes in the identified dietary factors will modulate cardiac function in cancer survivors., Competing Interests: Declaration of Competing Interest None., (Copyright © 2023. Published by Elsevier Inc.)

Despite improvements in cancer survival, cancer therapy-related cardiovascular toxicity has risen to become a prominent clinical challenge. This has led to the growth of the burgeoning field of cardio-oncology, which aims to advance the cardiovascular health of cancer patients and survivors, through actionable and translatable science. In these Global Cardio-Oncology Symposium 2023 scientific symposium proceedings, we present a focused review on the mechanisms that contribute to common cardiovascular toxicities discussed at this meeting, the ongoing international collaborative efforts to improve patient outcomes, and the bidirectional challenges of translating basic research to clinical care. We acknowledge that there are many additional therapies that are of significance but were not topics of discussion at this symposium. We hope that through this symposium-based review we can highlight the knowledge gaps and clinical priorities to inform the design of future studies that aim to prevent and mitigate cardiovascular disease in cancer patients and survivors., Competing Interests: Dr Salloum is supported by the National Heart, Lung, and Blood Institute of the National Institutes of Health under Award Numbers R35HL155651 and R44HL164314, and the American Heart Association Strategically Focused Research Network Award Number 23SFRNPCS1063855. Dr Tocchetti is supported by grants from the Italian Ministry of Health (PNRR-MAD-2022-12376632 and RF-2016-02362988). Dr Ameri is supported by the European Union - Next Generation EU - NRRP M6C2 - Investment 2.1 “Enhancement and strengthening of biomedical research in the NHS” (Italian Ministry of Health PNRR-MAD-2022-12376632). Dr Ardehali is supported by the National Heart, Lung, and Blood Institute of the National Institutes of Health under Award Numbers HL127646, HL140973, HL138982, and HL140927. Dr Asnani is supported by R01HL163172, R01HL166541, R01HL157530, and K08HL145019 from the National Institutes of Health/National Heart, Lung, and Blood Institute and by a sponsored research agreement with Genentech. Dr de Boer is supported by the Netherlands Heart Foundation (grants 2017-21, 2017-11, 2018-30, and 2020B005), the Leducq Foundation (Cure-PLaN), and the European Research Council (ERC CoG 818715). Dr Fernández-Velasco is supported by the Carlos III Health Institute (ISCIII) (PI20-01482 and PMP22/00098). Dr Fradley is funded by Medtronic and AstraZeneca. Dr Fuster is supported by grant RYC-2016-20026 from the Spanish Ministerio de Ciencia e Innovación (MICIN/AEI/10.13039/501100011033 and “ESF Investing in your future”) and the European Research Area Network on Cardiovascular Diseases CHEMICAL (grant AC19/00133, funded by ISCIII and co-funded by the European Union, ERDF, “A way to make Europe”). Drs Galán-Arriola, García-Lunar, Ibáñez, and Martin and the Centro Nacional de Investigaciones Cardiovasculares (CNIC) are supported by the ISCIII, the Ministry of Science and Innovation, and the Pro CNIC Foundation, and is a Severo Ochoa Center of Excellence (grant CEX2020-001041-S funded by MICIN/AEI/10.13039/501100011033). Dr Ibáñez is supported by a European Research Council grant (ERC-CoG 819775). The RESILIENCE project has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No 945118. Dr Kitsis is supported by the national Heart, Lung, and Blood Institute of the National Institutes of Health under Award Numbers R01HL159062, R01HL157319, R01HL164772, and DOD PR191593. Dr Martin is supported by MCIN-ISCIII-Fondo de Investigación Sanitaria (PI22/01759; PMPTA22/00090-BIOCARDIOTOX) and the Comunidad de Madrid (P2022/BMD-7209-INTEGRAMUNE-CM). Dr Mauro is supported by T32HL149645. Dr Mazo Vega is supported by European Union’s H2020 Program under grant agreement No 874827 (BRAV∃) and the Ministerio de Ciencia e Innovación CARDIOPRINT (PLEC2021-008127). Dr Neilan is supported by a gift from A. Curt Greer and Pamela Kohlberg and from Christina and Paul Kazilionis, the Michael and Kathryn Park Endowed Chair in Cardiology, and a Hassenfeld Scholar Award, and is supported by additional grant funding from the National Institutes of Health/National Heart, Lung, and Blood Institute under Award Numbers R01HL137562 and K24HL150238. Dr Rassaf is supported by the German Research Foundation Lower Saxony (DFG RA969/12-1), Ministry of Science and Culture REBIRTH I/II (ZN3440), and Stiftung Gerdes. Dr Ricke-Hoch is supported by the Lower Saxony Ministry of Science and Culture REBIRTH I/II (ZN3440) and Stiftung Gerdes. Dr van der Meer is supported by a grant from the European Research Council (ERC CoG 101045236, DISSECT-HF). Dr Thavendiranathan is supported by a Tier II Canada Research Chair in Cardiooncology (950-232646). Dr Ky is supported by National Institutes of Health grants R01 HL148272, R01 HL152707, R34 HL146927, R21 HL152148, R21HL157886, and K24 HL167127 and American Heart Association Strategically Focused Research Network Awards 849569 and 869105. Dr Sepulveda is supported by ISCIII (PMPTA2022/00011). Drs Ghigo, Lyon, Ibáñez, Hirsch, Ricke-Hoch, and Rassaf are supported by the Leducq Foundation Transatlantic Networks of Excellence (19CVD02). Dr Salloum has received consulting fees from Ring Therapeutics and funding from Novartis Pharmaceuticals, not related to this work; and served on the advisory board for NovoMedix, LLC, in cardio-oncology but not directly related to this work. Dr Tocchetti has received honoraria or consultation fees from VivaLyfe, Univers Formazione, Solaris, Summeet, AstraZeneca, and Myocardial Solutions; has received funding from Amgen and MSD, outside the submitted work; and is listed as an inventor of 2 patents related to heart failure. Dr Ameri has received speaker and/or advisor fees from AstraZeneca, Boehringer Ingelheim, Bayer, Novartis, Daiichi Sankyo, Janssen, and MSD, all outside the submitted work. Dr Asnani has served as a consultant or advisory board member for Sanofi, AstraZeneca, Cytokinetics, and OncLive; served as the principal investigator of a sponsored research agreement with Genentech; and received honoraria from UpToDate. Dr de Boer has received research grants and/or fees from AstraZeneca, Abbott, Boehringer Ingelheim, Cardior Pharmaceuticals GmbH, Ionis Pharmaceuticals, Novo Nordisk, and Roche; and served as a speaker for Abbott, AstraZeneca, Bayer, Bristol Myers Squibb, Novartis, and Roche. Dr Fradley has served as a consultant for AbbVie, AstraZeneca, Johnson and Johnson, Pfizer/Myovant, and Zoll. Drs Ghigo and Hirsch are co-founders and shareholders of Kither Biotech, a pharmaceutical company focused on the development of PI3K inhibitors for airway diseases not in conflict with the content of this paper. Dr Kitsis is a founder of ASPIDA Therapeutics Inc. Dr Lyon has received speaker, advisory board, or consulting fees and/or research grants from Pfizer, Novartis, Servier, AstraZeneca, Bristol Myers Squibb, GSK, Amgen, Takeda, Roche, Janssen-Cilag Ltd, Astellas Pharma, Clinigen Group, Eli Lilly, Eisai Ltd, Ferring Pharmaceuticals, Boehringer Ingelheim, Akcea Therapeutics, Myocardial Solutions, iOWNA Health, and Heartfelt Technologies Ltd. Dr Neilan has served as a consultant for and received fees from Bristol Myers Squibb, Genentech, CRC Oncology, Roche, Sanofi, and Parexel Imaging Pharmaceuticals; and received grant funding from AstraZeneca and Bristol Myers Squibb related to immune therapies. Dr Rassaf has received honoraria, lecture fees, and grant support from Edwards Lifesciences, AstraZeneca, Bayer, Novartis, Berlin Chemie, Daiichi Sankyo, Boehringer Ingelheim, Novo Nordisk, Cardiac Dimensions, and Pfizer, all unrelated to this work. Dr Thavendiranathan’s institution has received speaker honoraria or consultation fees from Amgen, Novartis, Boehringer Ingelheim, and Takeda. Dr van der Meer has received consulting fees and/or grants from Novartis, Pharmacosmos, Vifor Pharma, AstraZeneca, Pfizer, Pharma Nord, BridgeBio, Novo Nordisk, Boehringer Ingelheim, and Ionis. Dr Ky has received honoraria or grants from Pfizer; and honoraria from Roche, Bristol Myers Squibb, and AstraZeneca. Dr López-Fernández has received speaker fees from Philips, Janssen, Daichi Sankyo, Myocardial Solutions, AstraZeneca, Beigene, and Bayer, not related to the current work. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (© 2023 The Authors.)

The coexistence of cardiovascular disease and erectile dysfunction is widespread, possibly owing to underlying endothelial dysfunction in both diseases. Millions of patients with cardiovascular disease are prescribed phosphodiesterase-5 (PDE5) inhibitors for the management of erectile dysfunction. Although the role of PDE5 inhibitors in erectile dysfunction therapy is well established, their effects on the cardiovascular system are unclear. Preclinical studies investigating the effect of PDE5 inhibitors on ischemia-reperfusion injury, pressure overload-induced hypertrophy, and chemotoxicity suggested a possible clinical role for each of these medications; however, attempts to translate these findings to the bedside have resulted in mixed outcomes. In this review, we explore the biologic preclinical effects of PDE5 inhibitors in mediating cardioprotection. We then examine clinical trials investigating PDE5 inhibition in patients with heart failure, coronary artery disease, and ventricular arrhythmias and discuss why the studies likely have yet to show positive results and efficacy with PDE5 inhibition despite no safety concerns., (© 2021. Springer Science+Business Media, LLC, part of Springer Nature.)

Background: Cancer treatment increases cardiovascular disease risk, but physical activity (PA) may prevent cardiovascular disease., Objectives: This study examined whether greater PA was associated with better submaximal exercise capacity and cardiac function during cancer therapy., Methods: Participants included 223 women with stage I to III breast cancer (BC) before and 3 months after undergoing treatment and 126 control participants. Leisure-time PA (LTPA) was reported using the Godin-Shephard LTPA questionnaire. Cardiac function was assessed by cardiac magnetic resonance. Submaximal exercise capacity was determined by 6-minute walk distance., Results: BC participants reported similar baseline LTPA scores (24.7; 95% CI: 21.7-28.0) as control participants (29.4; 95% CI: 25.0-34.2). The BC group declined to 16.9 (95% CI: 14.4-19.6) at 3 months relative to 30.8 (95% CI: 26.2-35.8) in control participants. Among BC participants, more LTPA was related to better exercise capacity (β ± SE: 7.1 ± 1.6; 95% CI: 4.0-10.1) and left ventricular (LV) circumferential strain (-0.16 ± 0.07; 95% CI: -0.29 to -0.02). Increased LTPA over the 3 months was associated with decreased likelihood of treatment-induced cardiac dysfunction according to LV circumferential strain classifications (OR: 0.98; 95% CI: 0.97-0.998). BC participants reporting insufficient LTPA according to PA guidelines exhibited deteriorations in exercise capacity (adjusted mean difference ± SE: -29 ± 10 m; P  = 0.029), LV end-systolic volume (5.8 ± 1.3 mL; P  < 0.001), LV ejection fraction (-3.2% ± 0.8%; P  = 0.002), and LV circumferential strain (2.5% ± 0.5%; P  < 0.001), but BC participants meeting LTPA guidelines did not exhibit these adverse changes., Conclusions: PA declined during BC therapy; however, PA participation was associated with attenuated declines in exercise capacity and cardiac function that are often observed in this population. (Understanding and Predicting Breast Cancer Events After Treatment [WF97415 UPBEAT]; NCT02791581)., Competing Interests: Data collection was funded by the Wake Forest NCI Community Oncology Research Program (NCORP) Research Base grant 2UG1CA189824 with support of the NCORP. Additional funding for this study was provided by National Institutes of Health, National Cancer Institute grants R01CA199167 and T32CA093423. The authors have reported that they have no relationships relevant to the contents of this paper to disclose., (© 2023 The Authors.)

Despite significant advances and the continuous development of novel, effective therapies to treat a variety of malignancies, cancer therapy-induced cardiotoxicity has been identified as a prominent cause of morbidity and mortality, closely competing with secondary malignancies. This unfortunate limitation has prompted the inception of the field of cardio-oncology with its purpose to provide the necessary knowledge and key information on mechanisms that support the use of the most efficacious cancer therapy with minimal or no interruption while paying close attention to preventing cardiovascular related morbidity and mortality. Several mechanisms that contribute to cancer therapy-induced cardiotoxicity have been proposed and studied. These mainly involve mitochondrial dysfunction and reactive oxygen species-induced oxidative stress, lysosomal damage, impaired autophagy, cell senescence, DNA damage, and sterile inflammation with the formation and activation of the NLRP3 inflammasome. In this review, we focus on describing the principal mechanisms for different classes of cancer therapies that lead to cardiotoxicity involving the NLRP3 inflammasome. We also summarize current evidence of cardio-protection with inflammasome inhibitors in the context of heart disease in general, and further highlight the potential application of this evidence for clinical translation in at risk patients for the purpose of preventing cancer therapy associated cardiovascular morbidity and mortality., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Thermogenic fat differentiation and function can be promoted through multiple pathways, resulting in a common cell phenotype characterized by the expression of Uncoupling Protein-1 and the ability to dissipate energy, but local and systemic stimuli are necessary to promote adequate thermogenic fat vascularization, which is a precondition for the transport of substrate and the dissipation of heat. Angiopoietin-2 is an important driver of vascularization, and its transcription is in part promoted by estrogen signaling. In this study we demonstrate that adipose tissue-specific knock out of Angiopoietin-2 causes a female-specific reduced thermogenic fat differentiation and function, resulting in obesity and impaired glucose tolerance with end-organ features consistent with metabolic syndrome. In humans, angiopoietin-2 levels are higher in females than in males, and are inversely correlated with adiposity and age more strongly in pre-menopause when compared to post-menopause. Collectively, these data indicate a novel and important role for estrogen-mediated Angiopoietin-2 adipose tissue production in the protection against calorie overload in females, and potentially in the development of postmenopausal weight gain., (Copyright © 2022 The Author(s). Published by Elsevier GmbH.. All rights reserved.)

Background: Hydrogen sulfide (H 2 S) exerts mitochondria-specific actions that include the preservation of oxidative phosphorylation, biogenesis, and ATP synthesis, while inhibiting cell death. 3-MST (3-mercaptopyruvate sulfurtransferase) is a mitochondrial H 2 S-producing enzyme whose functions in the cardiovascular disease are not fully understood. In the current study, we investigated the effects of global 3-MST deficiency in the setting of pressure overload-induced heart failure., Methods: Human myocardial samples obtained from patients with heart failure undergoing cardiac surgeries were probed for 3-MST protein expression. 3-MST knockout mice and C57BL/6J wild-type mice were subjected to transverse aortic constriction to induce pressure overload heart failure with reduced ejection fraction. Cardiac structure and function, vascular reactivity, exercise performance, mitochondrial respiration, and ATP synthesis efficiency were assessed. In addition, untargeted metabolomics were utilized to identify key pathways altered by 3-MST deficiency., Results: Myocardial 3-MST was significantly reduced in patients with heart failure compared with nonfailing controls. 3-MST KO mice exhibited increased accumulation of branched-chain amino acids in the myocardium, which was associated with reduced mitochondrial respiration and ATP synthesis, exacerbated cardiac and vascular dysfunction, and worsened exercise performance following transverse aortic constriction. Restoring myocardial branched-chain amino acid catabolism with 3,6-dichlorobenzo1[b]thiophene-2-carboxylic acid (BT2) and administration of a potent H 2 S donor JK-1 ameliorates the detrimental effects of 3-MST deficiency in heart failure with reduced ejection fraction., Conclusions: Our data suggest that 3-MST derived mitochondrial H 2 S may play a regulatory role in branched-chain amino acid catabolism and mediate critical cardiovascular protection in heart failure.

Relaxin is a pleiotropic hormone demonstrated to confer cardioprotection in animal models of myocardial infarction and ischemic heart failure by modulating inflammation, fibrosis and arrhythmogenesis. Several of these pathways in the ischemic myocardium are intricately tied with the downstream signaling of bioactive sphingolipids, which play an active role during post-infarction remodeling. In this current study, we examined the effects of relaxin on sphingosine 1-phosphate (S1P), and the potential benefits of relaxin treatment on cardiac health in a rodent model of ischemic heart failure. Acute (30 min) and sub-acute (24 h) treatment of primary cardiomyocytes with serelaxin (recombinant human relaxin-2) increased the cardiomyocyte content of S1P. In the rodent model, treatment with relaxin for 28 days following myocardial ischemia by way of permanent left coronary artery occlusion improved survival and cardiac function, reduced fibrosis and apoptosis, and mitigated the expression of several pro-inflammatory and pro-fibrotic markers. The expression of beclin-1 (autophagy marker) was also reduced. The expression of S1P was significantly higher in cardiac tissue and plasma samples extracted from serelaxin-treated mice at day 28. In conclusion, our studies show a significant protection from relaxin in ischemic heart disease, and demonstrate the association between relaxin signaling and S1P generation., (© 2022. The Author(s).)

Duchenne muscular dystrophy (DMD) is a devastating disease affecting approximately 1 in every 3,500 male births worldwide. Multiple mutations in the dystrophin gene have been implicated as underlying causes of DMD. However, there remains no cure for patients with DMD, and cardiomyopathy has become the most common cause of death in the affected population. Extensive research is under way investigating molecular mechanisms that highlight potential therapeutic targets for the development of pharmacotherapy for DMD cardiomyopathy. In this paper, the authors perform a literature review reporting on recent ongoing efforts to identify novel therapeutic strategies to reduce, prevent, or reverse progression of cardiac dysfunction in DMD., Competing Interests: This work was supported by the National Heart, Lung, and Blood Institute of the National Institutes of Health under grants R35HL155651 (Dr Salloum) and K08HL155852 (Dr Raucci). The authors have reported that they have no relationships relevant to the contents of this paper to disclose., (© 2022 The Authors.)

The quest of defeating cancer and improving prognosis in survivors has generated remarkable strides forward in research and have advanced the development of new antineoplastic therapies. These achievements, combined with rapid screening and early detection, have considerably extended the life expectancy of patients surviving multiple types of malignancies. Consequently, chemotherapy-related toxicity in several organ systems, especially the cardiovascular system, has surfaced as one of the leading causes of morbidity and mortality among cancer survivors. Recent evidence classifies chemotherapy-induced cardiotoxicity as the second-leading cause of morbidity and mortality, closely comparing with secondary cancer malignancies. While a certain degree of cardiotoxicity has been reported to accompany most chemotherapies, including anthracyclines, anti-metabolites, and alkylating agents, even the latest targeted cancer therapies such as immune checkpoint inhibitors and tyrosine kinase inhibitors have been associated with acute and chronic cardiac sequelae. In this chapter, we focus on describing the principal mechanism(s) for each class of chemotherapeutic agents that lead to cardiotoxicity and the innovative translational research approaches that are currently being explored to prevent or treat cancer therapy-induced cardiotoxicity and related cardiac complications., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Relaxin is a pleiotropic hormone shown to confer cardioprotection in several preclinical models of cardiac ischemia-reperfusion injury. In the present study, the effects of up-regulating relaxin family peptide receptor 1 (RXFP1) via adeno-associated virus serotype 9 (AAV9) vectors were investigated in a mouse model of myocardial infarction. AAV9-RXFP1 vectors were generated and injected in adult male CD1 mice. Up-regulation of Rxfp1 was confirmed via quantitative polymerase chain reaction, and overexpressing animals showed increased sensitivity to relaxin-induced ventricular inotropic response. Overexpressing animals also demonstrated reduced infarct size and preserved cardiac function 24 hours after ischemia-reperfusion. Up-regulation of RXFP1 via AAV9 vectors has potential therapeutic utility in preventing adverse remodeling after myocardial infarction., Competing Interests: This study was supported by the American Heart Association (grant 18PRE33990001 to Mr Devarakonda), the Wright Center for Clinical and Translational Research Center (Wright Scholarship to Mr Devarakonda), and the National Institutes of Health (grants R01HL142281, R21AG053654, R01HL133167, and R35HL155651 to Dr Salloum). The authors have reported that they have no relationships relevant to the contents of this paper to disclose., (© 2022 The Authors.)

Background: Duchenne muscular dystrophy (DMD) is characterized by the lack of dystrophin in skeletal, cardiac, and smooth muscle. Slow colonic transit and constipation are common in DMD patients and animal models of DMD. However, the cause of this hypocontractility and the expression of contractile proteins in smooth muscle are unknown. The aim of the study was to investigate the expression of contractile proteins in the colonic smooth muscle and the function of the colon in control and mdx mice., Methods: Muscle contraction was measured in muscle strips and isolated muscle cells. Peristaltic activity was measured in ex vivo preparations by spatiotemporal mapping, and gastrointestinal (GI) transit in vivo was measured by the distribution of fluorescent marker along the intestine and colon. mRNA expression of contractile proteins smoothelin, caldesmon, calponin, and tropomyosin was measured by qRT-PCR., Results: Expression of mRNA for contractile proteins was decreased in colonic smooth muscle of mdx mice compared with control. Contraction in response to acetylcholine and KCl was decreased in colonic muscle strips and in isolated muscle cells of mdx mice. Distension of ex vivo colons with Krebs buffer induced peristalsis in both control and mdx mice; however, significantly fewer full peristaltic waves were recorded in the colons of mdx mice. GI transit was also inhibited in mdx mice., Conclusion and Inferences: The data indicate that the lack of dystrophin causes decrease in colonic smooth muscle contractility, peristalsis, and GI transit and provides the basis for analysis of mechanisms involved in smooth muscle dysfunction in DMD., (© 2020 John Wiley & Sons Ltd.)

Aims: Deregulation of mTOR (mammalian target of rapamycin) signalling occurs in diabetes, which exacerbates injury following myocardial infarction (MI). We therefore investigated the infarct-limiting effect of chronic treatment with rapamycin (RAPA, mTOR inhibitor) in diabetic mice following myocardial ischaemia/reperfusion (I/R) injury and delineated the potential protective mechanism., Methods and Results: Adult male diabetic (db/db) or wild-type (WT) (C57) mice were treated with RAPA (0.25 mg/kg/day, intraperitoneal) or vehicle (5% DMSO) for 28 days. The hearts from treated mice were subjected to global I/R in Langendorff mode. Cardiomyocytes, isolated from treated mice, were subjected to simulated ischaemia/reoxygenation (SI/RO) to assess necrosis and apoptosis. Myocardial infarct size was increased in diabetic heart following I/R as compared to WT. Likewise, enhanced necrosis and apoptosis were observed in isolated cardiomyocytes of diabetic mice following SI/RO. Treatment with RAPA reduced infarct size as well as cardiomyocyte necrosis and apoptosis of diabetes and WT mice. RAPA increased STAT3 phosphorylation and miRNA-17/20a expression in diabetic hearts. In addition, RAPA restored AKT phosphorylation (target of mTORC2) but suppressed S6 phosphorylation (target of mTORC1) following I/R injury. RAPA-induced cardioprotection against I/R injury as well as the induction of miR-17/20a and AKT phosphorylation were abolished in cardiac-specific STAT3-deficient diabetic mice, without alteration of S6 phosphorylation. The infarct-limiting effect of RAPA was obliterated in cardiac-specific miRNA-17-92-deficient diabetic mice. The post-I/R restoration of phosphorylation of STAT3 and AKT with RAPA were also abolished in miRNA-17-92-deficient diabetic mice. Additionally, RAPA suppressed the pro-apoptotic prolyl hydroxylase (Egln3/PHD3), a target of miRNA-17/20a in diabetic hearts, which was abrogated in miRNA-17-92-deficient diabetic mice., Conclusion: Induction of STAT3-miRNA-17-92 signalling axis plays a critical role in attenuating MI in RAPA-treated diabetic mice. Our study indicates that chronic treatment with RAPA might be a promising pharmacological intervention for attenuating MI and improving prognosis in diabetic patients., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author(s) 2019. For permissions, please email: journals.permissions@oup.com.)

Aims: Hydrogen sulfide (H 2 S) protects against ischemic and inflammatory injury following myocardial ischemia via induction of microRNA (miR)-21. We sought to determine whether H 2 S attenuates ischemic heart failure with reduced ejection fraction (HFrEF) and interrogate the role of cofilin-2, a target of miR-21, in this protective process., Methods and Results: Adult male mice underwent myocardial infarction (MI) by coronary artery ligation after baseline echocardiography. Following MI, mice were treated with Na 2 S (100 μg/kg/day; intraperitoneal [IP]) or saline up to 28 days. End-diastolic pressure, measured by Millar catheter, was significantly increased ( P < .05 vs sham) at 3 days post-MI in the saline group, which was attenuated with Na 2 S. Left ventricular (LV) fractional shortening decreased significantly at 28 days post-MI in the saline group but was preserved with Na 2 S and LV infarct scar size was smaller in Na 2 S group as compared to control. Apoptotic signaling, measured by Bcl-2/Bax ratio, was significantly increased in the saline group but was mitigated with Na 2 S. Survival rate was 2-fold higher in Na 2 S group compared to saline control ( P < .05). Proteomic analysis and Matrix-Assisted Laser Desorption/Ionization-Time of Flight (TOF)/TOF tandem mass spectrometry identified significant changes in proapoptotic cofilin-2 expression, a specific target of miR-21, between saline- and sodium sulfide -treated mice at 28 days post-MI. Western blot analysis confirmed a significant increase in cofilin-2 after MI, which was suppressed with Na 2 S treatment. Chronic Na 2 S treatment also attenuated inflammasome formation and activation leading to reduction of maladaptive signaling., Conclusion: Na 2 S treatment after MI preserves LV function and improves survival through attenuation of inflammasome-mediated adverse remodeling. We propose H 2 S donors as promising therapeutic tools for ischemic HFrEF.

Abusive chronic alcohol consumption can cause metabolic and functional derangements in the heart and is a risk factor for development of non-ischemic cardiomyopathy. microRNA 214 (miR-214) is a molecular sensor of stress signals that negatively impacts cell survival. Considering cardioprotective and microRNA modulatory effects of sildenafil, a phosphodiesterase 5 (PDE5) inhibitor, we investigated the impact of chronic alcohol consumption on cardiac expression of miR-214 and its anti-apoptotic protein target, Bcl-2 and whether sildenafil attenuates such changes. Adult male FVB mice received unlimited access to either normal liquid diet (control), alcohol diet (35% daily calories intake), or alcohol + sildenafil (1 mg/kg/day, p.o.) for 14 weeks (n = 6-7/group). The alcohol-fed groups with or without sildenafil had increased total diet consumption and lower body weight as compared with controls. Echocardiography-assessed left ventricular function was unaltered by 14-week alcohol intake. Alcohol-fed group had 2.6-fold increase in miR-214 and significant decrease in Bcl-2 expression, along with enhanced phosphorylation of ERK1/2 and cleavage of PARP (marker of apoptotic DNA damage) in the heart. Co-ingestion with sildenafil blunted the alcohol-induced increase in miR-214, ERK1/2 phosphorylation, and maintained Bcl-2 and decreased PARP cleavage levels. In conclusion, chronic alcohol consumption triggers miR-214-mediated pro-apoptotic signaling in the heart, which was prevented by co-treatment with sildenafil. Thus, PDE5 inhibition may serve as a novel protective strategy against cardiac apoptosis due to chronic alcohol abuse.

Background Human relaxin-2 is a peptide hormone capable of pleiotropic effects in several organ systems. Its recombinant formulation (serelaxin) has been demonstrated to reduce infarct size and prevent excessive scar formation in animal models of cardiac ischemia-reperfusion injury. B7-33, a synthetically designed peptide analogous to B-chain of relaxin-2, invokes signaling at relaxin family peptide receptor 1 (cognate receptor for relaxin-2) by preferentially phosphorylating the mitogen-activated protein kinase extracellular signal-regulated kinase 1/2. We sought to investigate the effects of B7-33 treatment post ischemia-reperfusion injury in mice. Methods and Results Adult male CD1 mice were subjected to ischemia-reperfusion via ligation of left anterior descending artery for 30 minutes, followed by 24 hours or 7 days of reperfusion. Echocardiography was performed to assess cardiac function, and cardiac tissue was stained to determine infarct size at 24 hours. B7-33 significantly reduced infarct size (21.99% versus 45.32%; P =0.02) and preserved fractional shortening (29% versus 23%; P =0.02) compared with vehicle. The difference in fractional shortening further increased at 7 days post myocardial infarction (29% versus 20% for B7-33 and vehicle groups, respectively). In vitro , primary cardiomyocytes were isolated from adult hearts and subjected to simulated ischemia-reperfusion injury (simulated ischemia reoxygenation). B7-33 (50 and 100 nmol/L) improved cell survival and reduced the expression of GRP78 (glucose regulated protein), an endoplasmic reticulum stress marker. Subsequently, B7-33 (100 nmol/L) reduced tunicamycin (2.5 μg/mL) induced upregulation of GRP78 in an extracellular signal-regulated kinase 1/2-dependent manner. Conclusions B7-33 confers acute cardioprotection and limits myocardial infarction-related adverse remodeling in mice by attenuating cardiomyocyte death and endoplasmic reticulum stress as well as preserving cardiac function.

Recent studies have shown that arterial medial calcification is mediated by abnormal release of exosomes/small extracellular vesicles from vascular smooth muscle cells (VSMCs) and that small extracellular vesicle (sEV) secretion from cells is associated with lysosome activity. The present study was designed to investigate whether lysosomal expression of mucolipin-1, a product of the mouse Mcoln1 gene, contributes to lysosomal positioning and sEV secretion, thereby leading to arterial medial calcification (AMC) and stiffening. In Mcoln1 -/- mice, we found that a high dose of vitamin D (Vit D; 500,000 IU/kg/day) resulted in increased AMC compared to their wild-type littermates, which was accompanied by significant downregulation of SM22- α and upregulation of RUNX2 and osteopontin in the arterial media, indicating a phenotypic switch to osteogenic. It was also shown that significantly decreased co-localization of lysosome marker (Lamp-1) with lysosome coupling marker (Rab 7 and ALG-2) in the aortic wall of Mcoln1 -/- mice as compared to their wild-type littermates. Besides, Mcoln1 -/- mice showed significant increase in the expression of exosome/ sEV markers, CD63, and annexin-II (AnX2) in the arterial medial wall, accompanied by significantly reduced co-localization of lysosome marker (Lamp-1) with multivesicular body (MVB) marker (VPS16), suggesting a reduction of the lysosome-MVB interactions. In the plasma of Mcoln1 -/- mice, the number of sEVs significantly increased as compared to the wild-type littermates. Functionally, pulse wave velocity (PWV), an arterial stiffening indicator, was found significantly increased in Mcoln1 -/- mice, and Vit D treatment further enhanced such stiffening. All these data indicate that the Mcoln1 gene deletion in mice leads to abnormal lysosome positioning and increased sEV secretion, which may contribute to the arterial stiffness during the development of AMC.

Fatty acid oxidation (FAO) is a key bioenergetic pathway often dysregulated in diseases. The current knowledge on FAO regulators in mammalian cells is limited and sometimes controversial. Previous FAO analyses involve nonphysiological culture conditions or lack adequate quantification. We herein described a convenient and quantitative assay to monitor dynamic FAO activities of mammalian cells in physiologically relevant settings. The method enabled us to assess various molecular and pharmacological modulators of the FAO pathway in established cell lines, primary cells and mice. Surprisingly, many previously proposed FAO inhibitors such as ranolazine and trimetazidine lacked FAO-interfering activity. In comparison, etomoxir at low micromolar concentrations was sufficient to saturate its target proteins and to block cellular FAO function. Oxfenicine, on the other hand, acted as a partial inhibitor of FAO. As another class of FAO inhibitors that transcriptionally repress FAO genes, antagonists of peroxisome proliferator-activated receptors (PPARs), particularly that of PPARα, significantly decreased cellular FAO activity. Our assay also had sufficient sensitivity to monitor upregulation of FAO in response to environmental glucose depletion and other energy-demanding cues. Altogether this study provided a reliable FAO assay and a clear picture of biological properties of potential FAO modulators in the mammalian system.

Arterial medial calcification (AMC) is associated with crystallization of hydroxyapatite in the extracellular matrix and arterial smooth muscle cells (SMCs) leading to reduced arterial compliance. The study was performed to test whether lysosomal acid sphingomyelinase (murine gene code: Smpd1)-derived ceramide contributes to the small extracellular vesicle (sEV) secretion from SMCs and consequently leads to AMC. In Smpd1 trg /SM cre mice with SMC-specific overexpression of Smpd1 gene, a high dose of Vit D (500 000 IU/kg/d) resulted in increased aortic and coronary AMC, associated with augmented expression of RUNX2 and osteopontin in the coronary and aortic media compared with their littermates (Smpd1 trg /SM wt and WT/WT mice), indicating phenotypic switch. However, amitriptyline, an acid sphingomyelinase (ASM) inhibitor, reduced calcification and reversed phenotypic switch. Smpd1 trg /SM cre mice showed increased CD63, AnX2 and ALP levels in the arterial wall, accompanied by reduced co-localization of lysosome marker (Lamp-1) with multivesicular body (MVB) marker (VPS16), a parameter for lysosome-MVB interaction. All these changes related to lysosome fusion and sEV release were substantially attenuated by amitriptyline. Increased arterial stiffness and elastin disorganization were found in Smpd1 trg /SM cre mice as compared to their littermates. In cultured coronary arterial SMCs (CASMCs) from Smpd1 trg /SM cre mice, increased P i concentrations led to markedly increased calcium deposition, phenotypic change and sEV secretion compared with WT CASMCs, accompanied by reduced lysosome-MVB interaction. However, amitriptyline prevented these changes in P i -treated CASMCs. These data indicate that lysosomal ceramide plays a critical role in phenotype change and sEV release in SMCs, which may contribute to the arterial stiffness during the development of AMC., (© 2019 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.)

Objectives: Because of its multifaceted cardioprotective effects, remote ischemic pre-conditioning (RIPC) was examined as a strategy to attenuate doxorubicin (DOX) cardiotoxicity., Background: The use of DOX is limited by dose-dependent cardiotoxicity and heart failure. Oxidative stress, mitochondrial dysfunction, inflammation, and autophagy modulation have been proposed as mediators of DOX cardiotoxicity., Methods: After baseline echocardiography, adult male CD1 mice were randomized to either sham or RIPC protocol (3 cycles of 5 min femoral artery occlusion followed by 5 min reperfusion) 1 h before receiving DOX (20 mg/kg, intraperitoneal). The mice were observed primarily for survival over 85 days (86 mice). An additional cohort of 50 mice was randomized to either sham or RIPC 1 h before DOX treatment and was followed for 25 days, at which time cardiac fibrosis, apoptosis, and mitochondrial oxidative phosphorylation were assessed, as well as the expression profiles of apoptosis and autophagy markers., Results: Survival was significantly improved in the RIPC cohort compared with the sham cohort (p = 0.007). DOX-induced cardiac fibrosis and apoptosis were significantly attenuated with RIPC compared with sham (p < 0.05 and p < 0.001, respectively). Although no mitochondrial dysfunction was detected at 25 days, there was a significant increase in autophagy markers with DOX that was attenuated with RIPC. Moreover, DOX caused a 49% decline in cardiac BCL2/BAX expression, which was restored with RIPC (p < 0.05 vs. DOX). DOX also resulted in a 17% reduction in left ventricular mass at 25 days, which was prevented with RIPC (p < 0.01), despite the lack of significant changes in left ventricular ejection fraction., Conclusions: Our preclinical results suggested that RIPC before DOX administration might be a promising approach for attenuating DOX cardiotoxicity.

Background: In the heart, slow delayed rectifier channels provide outward currents (I Ks ) for action potential (AP) repolarization in a region- and context-dependent manner. In diseased hearts, chronic elevation of angiotensin II (Ang II) may remodel I Ks in a region-dependent manner, contributing to atrial and ventricular arrhythmias of different mechanisms., Objective: The purpose of this study was to study whether/how chronic in vivo Ang II administration remodels I Ks in atrial and ventricular myocytes., Methods: We used the guinea pig (GP) model whose myocytes express robust I Ks . GPs were implanted with minipumps containing Ang II or vehicle. Treatment continued for 4-6 weeks. We used patch clamp, immunofluorescence/confocal microscopy, and immunoblots to evaluate changes in I Ks function and to explore the underlying mechanisms., Results: We confirmed the pathologic state of the heart after chronic Ang II treatment. I Ks density was increased in atrial myocytes but decreased in ventricular myocytes in Ang II- vs vehicle-treated animals. The former was correlated with an increase in KCNQ1/KCNE1 colocalization in myocyte periphery, whereas the latter was correlated with a decrease in KCNQ1 protein level. Interestingly, these changes in I Ks were not translated into expected alterations in AP duration or plateau voltage, indicating that other currents were involved. In atrial myocytes from Ang II-treated animals, the L-type Ca channel current was increased, contributing to AP plateau elevation and AP duration prolongation., Conclusion: I Ks is differentially modulated by chronic in vivo Ang II administration between atrial and ventricular myocytes. Other currents remodeled by Ang II treatment also contribute to changes in action potentials., (Copyright © 2018 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Background: Sacubitril/valsartan (SAC/VAL) is approved by the U.S. Food and Drug Administration for heart failure with reduced ejection fraction (HFrEF)., Objectives: This study investigated the effects of SAC/VAL on acute myocardial infarction (MI) and cardiac remodeling in a translational rabbit model of MI., Methods: New Zealand White rabbits were sedated and underwent conscious MI (45-min ischemia) by balloon inflation (previously implanted surgically) followed by 72 h (acute protocol) or 10 weeks (chronic protocols) of reperfusion. "Infarct-sparing" protocol: SAC/VAL, VAL, or placebo were randomly allocated and administered at reperfusion. "HFrEF-treatment" protocol: rabbits were randomized, and treatment commenced after echocardiography-confirmed left ventricular ejection fraction (LVEF) ≤40%. "HFrEF-prevention" protocol: treatment started at reperfusion and continued daily throughout the study., Results: Compared with placebo, SAC/VAL and VAL significantly reduced infarct size (TTC staining) and plasma troponin levels; however, only SAC/VAL preserved LVEF at 72 h post-MI. In the HFrEF-treatment protocol, LVEF improvement was observed with SAC/VAL compared with both placebo and VAL starting 2 weeks post-treatment, a benefit that persisted throughout study duration. In the HFrEF-prevention protocol, SAC/VAL and VAL attenuated the decline in LVEF post-MI, although SAC/VAL offered better functional protection. The functional improvement observed in both treatment protocols was paralleled by significant reduction in left ventricular (LV) scar size (Picrosirius red staining) in the SAC/VAL groups., Conclusions: Reperfusion therapy with SAC/VAL or VAL offers robust acute infarct-sparing benefits; however, SAC/VAL treatment offered superior short-term and long-term benefits in preventing MI-induced LV dysfunction compared with VAL. SAC/VAL also significantly attenuated LV scar size following MI compared with placebo, whereas VAL did not reach statistical significance in scar reduction., (Copyright © 2018 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

After being long considered as "junk" in the human genome, non-coding RNAs (ncRNAs) currently represent one of the newest frontiers in cardiovascular disease (CVD) since they have emerged in recent years as potential therapeutic targets. Different types of ncRNAs exist, including small ncRNAs that have fewer than 200 nucleotides, which are mostly known as microRNAs (miRNAs), and long ncRNAs that have more than 200 nucleotides. Recent discoveries on the role of ncRNAs in epigenetic and transcriptional regulation, atherosclerosis, myocardial ischemia/reperfusion (I/R) injury and infarction (MI), adverse cardiac remodeling and hypertrophy, insulin resistance, and diabetic cardiomyopathy prompted vast interest in exploring candidate ncRNAs for utilization as potential therapeutic targets and/or diagnostic/prognostic biomarkers in CVDs. This review will discuss our current knowledge concerning the roles of different types of ncRNAs in cardiovascular health and disease and provide some insight on the cardioprotective signaling pathways elicited by the non-coding genome. We will highlight important basic and clinical breakthroughs that support employing ncRNAs for treatment or early diagnosis of a variety of CVDs, and also depict the most relevant limitations that challenge this novel therapeutic approach.

The hormone relaxin has long been recognized for its involvement in maternal adaptation during pregnancy. However, discoveries during the past two decades on the mechanism of action of relaxin, its family of receptors, and newly described roles in attenuating ischemia/reperfusion (I/R) injury, inflammation, and arrhythmias have prompted vast interest in exploring its therapeutic potential in cardiovascular disease. These observations inspired recently concluded clinical trials in patients with acute heart failure. This review discusses our current understanding of the protective signaling pathways elicited by relaxin in the heart, and highlights important new breakthroughs about relaxin signaling that may pave the way to more carefully designed future trials., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Background and Purpose: Enhanced mammalian target of rapamycin (mTOR) signalling contributes to the pathogenesis of diabetes and plays a critical role in myocardial ischaemia/reperfusion (I/R) injury. Rapatar is a novel nanoformulated micellar of rapamycin, a putative inhibitor of mTOR that has been rationally designed to increase water solubility of rapamycin to facilitate p.o. administration and enhance bioavailability. We examined the effect of Rapatar on the metabolic status and protection against myocardial I/R injury in type 2 diabetic mice., Experimental Approach: Adult male db/db mice were treated daily for 10 weeks with Rapatar (0.75 mg·kg -1 ·day -1 , p.o.) or vehicle. Isolated hearts were connected to a Langendorff perfusion system and subjected to global ischaemia (30 min) and reperfusion (1 h)., Key Results: Rapatar reduced fasting plasma glucose and triglyceride levels, prevented the gain in body weight and also improved glucose tolerance and insulin sensitivity in db/db mice compared with control. Cardiac function was improved following Rapatar treatment in db/db mice. Myocardial infarct size was reduced in Rapatar-treated mice with improved post-ischaemic rate-force product. Western blot analyses demonstrated a significant inhibition of phosphorylation of ribosomal protein S6 (downstream target of mTORC1), but not Akt (Ser 473 , target of mTORC2) following chronic treatment with Rapatar. Rapatar also induced phosphorylation of AMPK, STAT3, ERK1/2 and glycogen synthase kinase 3β, without interfering with phosphorylation of p38., Conclusion and Implications: Our studies indicate that chronic treatment with Rapatar improves metabolic status and cardiac function with a reduction of infarct size following myocardial I/R injury in diabetic mice., (© 2017 The British Pharmacological Society.)

Background: The area of myocardial infarction continues to expand for hours after reperfusion. The injured but viable myocardium may be salvaged if the signals leading to cell death are interrupted. Activation of the caspase-1 inflammasome in the heart shortly after ischemia-reperfusion contributes to the final infarct size. Plasma-derived α-1 anti-trypsin (AAT) has shown to inhibit inflammasome formation in vitro and in vivo. To explore the potential translational clinical value of AAT as a therapeutic, we conducted a series of preclinical experiments designed to simulate clinically relevant scenarios., Methods: Adult male CD1 mice were used. The left anterior descending coronary artery was ligated for 30 or 75 minutes followed by reperfusion, to explore different severity of ischemic injury. Plasma-derived AAT (Prolastin C) was administered intraperitoneally after reperfusion, without pretreatment, exploring 3 different doses (60, 120, and 180 mg/kg). In a subgroup of mice, we administered Prolastin C with a delay of 30 minutes after reperfusion to simulate the clinical context of delayed administration, and we also used a model of permanent coronary artery ligation without reperfusion. Finally, we tested whether a single dose at reperfusion was sufficient to maintain a benefit in the longer term (7 days). Infarct size was measured by 3 different and independent methodologies: pathology, plasma levels of troponin I, and wall motion abnormalities at echocardiography., Results: Prolastin C given at reperfusion after 30 minutes of ischemia provided a powerful reduction in infarct size (>50% reduction in all methodology used, all P < 0.01) without a clear dose-dependent response. Prolongation of ischemia to 75 minutes nor a delay in treatment by 30 minutes after reperfusion had any negative impact on Prolastin C effects. A single dose given at reperfusion was as effective as multiple daily doses. When given to the mouse without reperfusion, Prolastin C failed to reduce infarct size., Conclusions: Plasma-derived AAT (Prolastin C) given as an adjunct to reperfusion powerfully limits the final infarct size across a wide range of experiments in the mouse reproducing clinically relevant scenarios, such as variable duration of ischemia, delay in administration in the drug, and a large therapeutic index.

Aims: The preconditioning-like infarct-sparing and anti-inflammatory effects of the peptide hormone relaxin following ischemic injury have been studied in the heart. Whether reperfusion therapy with recombinant human relaxin-2, serelaxin, reduces myocardial infarct size and attenuates the subsequent NLRP3 inflammasome activation leading to further loss of functional myocardium following ischemia/reperfusion (I/R) injury is unknown., Methods and Results: After baseline echocardiography, adult male wild-type C57BL or eNOS knockout mice underwent myocardial infarction (MI) by coronary artery ligation for 30 min followed by 24 h reperfusion. Mice were treated with either serelaxin (10 µg/kg; sc) or saline 1 h prior to ischemia or 5 min before reperfusion. In both pre-treatment and reperfusion therapy arms, serelaxin improved survival at 24 h post MI in wild-type mice (79% and 82%) as compared with controls (46% and 50%, P = 0.01), whereas there was no difference in survival between serelaxin- and saline-treated eNOS knockout mice. Moreover, serelaxin significantly reduced infarct size (64% and 67% reduction, P < 0.05), measured with TTC staining, and preserved LV fractional shortening (FS) and end-systolic diameter (LVESD) in wild-type mice as compared with controls (P < 0.05). Interestingly, caspase-1 activity in the heart tissue, a measure of inflammasome formation, was markedly reduced in serelaxin-treated wild-type mice compared with controls at 24 h post-MI in both treatment modalities (P < 0.05). Genetic deletion of eNOS abolished the infarct-sparing and anti-inflammatory effects of serelaxin as well as functional preservation. Serelaxin plasma levels assessed at 5 min and 1 h after treatment, using ELISA, approximated physiologic relaxin levels during pregnancy in mice and parallels that in humans., Conclusion: Serelaxin attenuates myocardial I/R injury and the subsequent caspase-1 activation via eNOS-dependent mechanism., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2017. For permissions, please email: journals.permissions@oup.com.)

Prompt coronary reperfusion is the gold standard for minimizing injury following acute myocardial infarction. Rapamycin, mammalian target of Rapamycin (mTOR) inhibitor, exerts preconditioning-like cardioprotective effects against ischemia/reperfusion (I/R) injury. We hypothesized that Rapamycin, given at the onset of reperfusion, reduces myocardial infarct size through modulation of mTOR complexes. Adult C57 male mice were subjected to 30 min of myocardial ischemia followed by reperfusion for 1 hour/24 hours. Rapamycin (0.25 mg/kg) or DMSO (7.5%) was injected intracardially at the onset of reperfusion. Post-I/R survival (87%) and cardiac function (fractional shortening, FS: 28.63 ± 3.01%) were improved in Rapamycin-treated mice compared to DMSO (survival: 63%, FS: 17.4 ± 2.6%). Rapamycin caused significant reduction in myocardial infarct size (IS: 26.2 ± 2.2%) and apoptosis (2.87 ± 0.64%) as compared to DMSO-treated mice (IS: 47.0 ± 2.3%; apoptosis: 7.39 ± 0.81%). Rapamycin induced phosphorylation of AKT S473 (target of mTORC2) but abolished ribosomal protein S6 phosphorylation (target of mTORC1) after I/R. Rapamycin induced phosphorylation of ERK1/2 but inhibited p38 phosphorylation. Infarct-limiting effect of Rapamycin was abolished with ERK inhibitor, PD98059. Rapamycin also attenuated Bax and increased Bcl-2/Bax ratio. These results suggest that reperfusion therapy with Rapamycin protects the heart against I/R injury by selective activation of mTORC2 and ERK with concurrent inhibition of mTORC1 and p38., Competing Interests: On behalf of all authors, the corresponding author states that there is no conflict of interests.

Pulmonary hypertension (PH) is common in patients with heart failure with preserved ejection fraction (HFpEF). While PH-HFpEF may affect more than a million patients in the United States alone, it has been difficult to study its epidemiology and response to treatment due to difficulty in properly defining the illness. While chronic remodeling of the pulmonary vasculature is related to chronic passive congestion of the pulmonary circulation from the pulmonary veins, there are likely other contributors to the development of PH-HFpEF. We explore the potential direct contributions of obesity, diabetes mellitus, genetics, and sleep apnea on the pulmonary circulation in those with PH-HFpEF, and we discuss the potential role of exercise testing or fluid challenge during diagnostic testing., (Copyright © 2016 Elsevier Inc. All rights reserved.)

The peptide hormone relaxin has traditionally been linked to the maternal adaptation of the cardiovascular system during the first trimester of pregnancy. By promoting nitric oxide formation through different molecular signaling events, relaxin has been proposed as a pleiotropic and cardioprotective hormone in the setting of many cardiovascular diseases. In fact, preclinical studies were able to demonstrate that relaxin promotes vasodilatation and angiogenesis, ameliorates ischemia/reperfusion injury, and regulates extracellular matrix turnover and remodeling. In the RELAX-AHF phase 3 clinical trial, serelaxin (recombinant human relaxin) was shown to be safe, and it exerted survival benefits in patients with acute heart failure. RELAX-AHF-2 is currently ongoing, and it aims to address a larger population and evaluate harder clinical outcomes. Besides heart failure, acute myocardial infarction, peripheral arterial disease, and stable coronary disease could be target diseases for treatment with serelaxin in future clinical trials., (© The Author(s) 2015.)

Heart transplantation (HTx) is the ultimate treatment for end-stage heart failure. The number of patients on waiting lists for heart transplants, however, is much higher than the number of available organs. The shortage of donor hearts is a serious concern since the population affected by heart failure is constantly increasing. Furthermore, the long-term success of HTx poses some challenges despite the improvement in the management of the short-term complications and in the methods to limit graft rejection. Myocardial injury occurs during transplantation. Injury initiated in the donor as result of brain or cardiac death is exacerbated by organ procurement and storage, and is ultimately amplified by reperfusion injury at the time of transplantation. The innate immune system is a mechanism of first-line defense against pathogens and cell injury. Innate immunity is activated during myocardial injury and produces deleterious effects on the heart structure and function. Here, we briefly discuss the role of the innate immunity in the initiation of myocardial injury, with particular focus on the Toll-like receptors and inflammasome, and how to potentially expand the donor population by targeting the innate immune response.

Background: Successful reperfusion is the most effective strategy to reduce ischemic injury in acute myocardial infarction (AMI). Ischemic injury, however, also triggers a secondary ischemia-independent injury, known as reperfusion injury, contributing to the overall infarct size. We hypothesize that inhibition of the Nod-like Receptor Protein-3 (NLRP3) inflammasome limits infarct size following myocardial ischemia/reperfusion (I/R), by inhibiting the inflammatory component of the reperfusion injury., Methods: CD-1 male mice underwent transient ligation of the left anterior descending coronary artery for 30 or 75min followed by reperfusion. Infarct size was measured at 1, 3 and 24h. A NLRP3 inflammasome inhibitor (NLRP3inh) or vehicle was administrated immediately at time of reperfusion or with a delay of 1 or 3h of reperfusion., Results: A time-dependent increase in infarct size was measured at 1, 3, and 24h after reperfusion (11±2%, 30±5% and 43±4% of the area at risk respectively; P<0.001 for trend). NLRP3 myocardial expression was significantly increased at 24h and 6h vs 3h (P<0.01). Administration of the NLRP3inh at reperfusion did not reduce infarct size at 3h, while it significantly reduced infarct size at 24h (-56% vs vehicle, P<0.01). The NLRP3inh given 1h after reperfusion also significantly decreased caspase-1 activity and infarct size measured at 24h, whereas the NLRP3inh did not when given with a delay of 3h., Conclusions: Pharmacological inhibition of the NLRP3 inflammasome within 1h of reperfusion limits the secondary inflammatory injury and infarct size following myocardial ischemia-reperfusion in the mouse., (Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.)

Signal transducer and activator of transcription 3 (STAT3) is a transcription factor that contributes a crucial role in protection against ischemia (ISC)-reperfusion (REP) injury by driving expression of anti-apoptotic and anti-oxidant genes. STAT3 is also present in the mitochondria, where it modulates the activity of the electron transport chain (ETC) and the permeability transition pore. Transgenic mice that overexpress a mitochondrial-targeted, transcriptionally inactive STAT3 in cardiomyocytes (MLS-STAT3E mice) exhibit a persistent, partial blockade of electron transfer through complex I that uniquely did not lead to tissue dysfunction at baseline, yet increased mitochondrial ischemic tolerance. The direct contribution of non-transcriptional, mitochondria-localized STAT3 to protection during ISC-REP remains to be established. We hypothesized that the enhanced mitochondrial tolerance to ischemia present in MLS-STAT3E mice would decrease cardiac injury during ISC-REP. In the isolated buffer-perfused heart model, MLS-STAT3E hearts exhibit a decreased infarct size compared to non-transgenic littermate hearts. Contractile recovery, expressed as a percent of LV developed pressure before ISC, is improved in MLS-STAT3E mice. Mitochondria isolated at the end of 60 min. of REP from MLS-STAT3E hearts show attenuated ROS release. The partial and persistent blockade of complex I present in MLS-STAT3E mice decreases cardiac injury during REP, in part via a persistent decrease in ROS production and attenuation of mitochondrial permeability transition pore opening at the onset of REP. In vivo, MLS-STAT3E hearts exhibit substantially higher postoperative survival rate and a substantial decrease in myocardial infarct size. STAT3 mediates cardioprotection not only via canonical action as a transcription factor, but also as a modulator of ETC activity directly in the mitochondria.

Heart failure (HF) with preserved ejection fraction (HFpEF) is a clinical syndrome of HF symptoms associated with impaired diastolic function. Although it represents ∼50% of patients with HF, the mechanisms of disease are poorly understood, and therapies are generally ineffective in reducing HF progression. Animal models of HFpEF not due to pressure or volume overload are lacking, therefore limiting in-depth understanding of the pathophysiological mechanisms and the development of novel therapies. We hypothesize that a continuous infusion of low-dose angiotensin II (ATII) is sufficient to induce left ventricular (LV) diastolic dysfunction and HFpEF, without increasing blood pressure or inducing LV hypertrophy or dilatation. Osmotic pumps were implanted subcutaneously in 8-wk-old male mice assigned to the ATII (0.2 mg·kg(-1)·day(-1)) or volume-matched vehicle (N = 8/group) for 4 wk. We measured systolic and diastolic arterial blood pressures through a tail-cuff transducer, LV dimensions and ejection fraction through echocardiography, and LV relaxation through pulsed-wave Doppler and LV catheterization. Myocardial fibrosis and cardiomyocyte cross-sectional area were measured. ATII infusion had no effects on systemic arterial blood pressure. ATII induced significant impairment in LV diastolic function, as measured by an increase (worsening) in LV isovolumetric relaxation time, myocardial performance index, isovolumetric relaxation time constant, and LV end-diastolic pressure without altering LV dimensions, mass, or ejection fraction. Chronic infusion of low-dose ATII recapitulates the HFpEF phenotype in the mouse, without increasing systemic arterial blood pressure. This mouse model may provide insight into the mechanisms of HFpEF., (Copyright © 2015 the American Physiological Society.)

Hydrogen sulfide (H2S) has been long recognized as a highly poisonous gas that is rapidly lethal in intoxicating dosage. However, discoveries during the last decade on the endogenous synthesis of H2S in the mammalian system and its protective role in combating cellular necrosis, apoptosis, oxidative stress, inflammation as well as promoting angiogenesis and modulation of mitochondrial respiration in the setting of myocardial ischemia and reperfusion injury have prompted vast interest in the possibility of developing new therapies based around mimicry or facilitation of endogenous H2S for cardioprotection. These observations have inspired rapid development of H2S-releasing drugs in hopes of swift clinical translation in patients with cardiovascular disease. This review will discuss our current understanding of the protective signaling pathways elicited by H2S in the heart with an emphasis on the versatile benefits of this gasotransmitter and its potential for clinical translation in patients with cardiovascular disease., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Background: Sterile inflammation resulting from myocardial injury activates the NLRP3 inflammasome and amplifies the inflammatory response mediating further damage., Methods: We used 2 experimental models of ischemic injury (acute myocardial infarction [AMI] with and without reperfusion) and a model of nonischemic injury due to doxorubicin 10 mg/kg to determine whether the NLRP3 inflammasome preserved cardiac function after injury., Results: Treatment with the NLRP3 inflammasome inhibitor in the reperfused AMI model caused a significant reduction in infarct size measured at pathology or as serum cardiac troponin I level (-56% and -82%, respectively, both P < 0.001) and preserved left ventricular fractional shortening (LVFS, 31 ± 2 vs. vehicle 26% ± 1%, P = 0.003). In the non-reperfused AMI model, treatment with the NLRP3 inhibitor significantly limited LV systolic dysfunction at 7 days (LVFS of 20 ± 2 vs. 14% ± 1%, P = 0.002), without a significant effect on infarct size. In the doxorubicin model, a significant increase in myocardial interstitial fibrosis and a decline in systolic function were seen in vehicle-treated mice, whereas treatment with the NLRP3 inhibitor significantly reduced fibrosis (-80%, P = 0.001) and preserved systolic function (LVFS 35 ± 2 vs. vehicle 27% ± 2%, P = 0.017)., Conclusions: Pharmacological inhibition of the NLRP3 inflammasome limits cell death and LV systolic dysfunction after ischemic and nonischemic injury in the mouse.

Diabetic patients suffer augmented severity of myocardial infarction. Excessive activation of the mammalian target of rapamycin (mTOR) and decreased activation of STAT3 are implicated in diabetic complications. Considering the potent cardioprotective effect of mTOR inhibitor, rapamycin, we hypothesized that reperfusion therapy with rapamycin would reduce infarct size in the diabetic hearts through STAT3 signaling. Hearts from adult male db/db or wild type (WT) C57 mice were isolated and subjected to 30 min of normothermic global ischemia and 60 min of reperfusion in Langendorff mode. Rapamycin (100 nM) was infused at the onset of reperfusion. Myocardial infarct size (IS) was significantly reduced in rapamycin-treated mice (13.3 ± 2.4 %) compared to DMSO vehicle control (35.9 ± 0.9 %) or WT mice (27.7 ± 1.1 %). Rapamycin treatment restored phosphorylation of STAT3 and enhanced AKT phosphorylation (target of mTORC2), but significantly reduced ribosomal protein S6 phosphorylation (target of mTORC1) in the diabetic heart. To determine the cause and effect relationship of STAT3 in cardioprotection, inducible cardiac-specific STAT3-deficient (MCM TG:STAT3(flox/flox)) and WT mice (MCM TG:STAT3(flox/flox)) were made diabetic by feeding high fat diet (HFD). Rapamycin given at reperfusion reduced IS in WT mice but not in STAT3-deficient mice following I/R. Moreover, cardiomyocytes isolated from HFD-fed WT mice showed resistance against necrosis (trypan blue staining) and apoptosis (TUNEL assay) when treated with rapamycin during reoxygenation following simulated ischemia. Such protection was absent in cardiomyocytes from HFD-fed STAT3-deficient mice. STAT3 signaling plays critical role in reducing IS and attenuates cardiomyocyte death following reperfusion therapy with rapamycin in diabetic heart.