Long-term dietary n3 fatty acid prevents aging-related cardiac diastolic and vascular dysfunction.

AIMS: The prevalence of left ventricular (LV) diastolic and vascular dysfunction increases with age, eventually leading to heart failure with preserved ejection fraction (HFpEF). A preventive strategy is an unmet medical need. We and others reported previously on the beneficial effects of omega-3 fatty acid alpha linolenic acid (ALA) on cardiovascular disorders in animal models and translational studies. We now investigate whether long-term dietary ALA could prevent LV diastolic dysfunction and vascular aging in a murine model. METHODS AND RESULTS: Wild-type C57BL/6 J mice were fed a chow or ALA diet for 12 months, starting at 6 months of age. Here, we show that aged (~18 months) mice recapitulate major hallmarks of HFpEF, including LV diastolic dysfunction with preserved ejection fraction, impaired vascular function, cardiac fibrosis, arterial stiffening and inflammation, as well as elevated B-type natriuretic peptide (BNP). Long-term ALA supplementation upregulated the mitochondrial tricarboxylic acid enzyme Idh2 and the antioxidant enzymes SOD1 and Gpx1. It also has been associated with reduced inflammation and ECM remodeling, accompanied by a significant downregulation of fibrosis biomarkers MMP-2 and TGF-ß in both cardiac and vascular tissues obtained from aged mice. Our data exhibited the preventive effects of dietary ALA against LV diastolic dysfunction, impaired vasorelaxation, cardiac fibrosis, inflammation and arterial stiffening in aged mice. CONCLUSIONS: We provide evidence and a simplified mechanistic insight on how long-term ALA supplementation is a successful strategy to prevent the development of age-related diastolic and vascular dysfunction.

Cardioprotective Effect of Acute Intradialytic Exercise: A Comprehensive Speckle-Tracking Echocardiography Analysis.

SIGNIFICANCE STATEMENT: Hemodialysis (HD) can lead to acute left ventricular (LV) myocardial wall motion abnormalities (myocardial stunning) due to segmental hypoperfusion. Exercise during dialysis is associated with favorable effects on central hemodynamics and BP stability, factors considered in the etiology of HD-induced myocardial stunning. In a speckle-tracking echocardiography analysis, the authors explored effects of acute intradialytic exercise (IDE) on LV regional myocardial function in 60 patients undergoing HD. They found beneficial effects of IDE on LV longitudinal and circumferential function and on torsional mechanics, not accounted for by cardiac loading conditions or central hemodynamics. These findings support the implementation of IDE in people with ESKD, given that LV transient dysfunction imposed by repetitive HD may contribute to heart failure and increased risk of cardiac events in such patients. BACKGROUND: Hemodialysis (HD) induces left ventricular (LV) transient myocardial dysfunction. A complex interplay between linear deformations and torsional mechanics underlies LV myocardial performance. Although intradialytic exercise (IDE) induces favorable effects on central hemodynamics, its effect on myocardial mechanics has never been comprehensively documented. METHODS: To evaluate the effects of IDE on LV myocardial mechanics, assessed by speckle-tracking echocardiography, we conducted a prospective, open-label, two-center randomized crossover trial. We enrolled 60 individuals with ESKD receiving HD, who were assigned to participate in two sessions performed in a randomized order: standard HD and HD incorporating 30 minutes of aerobic exercise (HDEX). We measured global longitudinal strain (GLS) at baseline (T0), 90 minutes after HD onset (T1), and 30 minutes before ending HD (T2). At T0 and T2, we also measured circumferential strain and twist, calculated as the net difference between apical and basal rotations. Central hemodynamic data (BP, cardiac output) also were collected. RESULTS: The decline in GLS observed during the HD procedure was attenuated in the HDEX sessions (estimated difference, -1.16%; 95% confidence interval [95% CI], -0.31 to -2.02; P = 0.008). Compared with HD, HDEX also demonstrated greater improvements from T0 to T2 in twist, an important component of LV myocardial function (estimated difference, 2.48°; 95% CI, 0.30 to 4.65; P = 0.02). Differences in changes from T0 to T2 for cardiac loading and intradialytic hemodynamics did not account for the beneficial effects of IDE on LV myocardial mechanics kinetics. CONCLUSIONS: IDE applied acutely during HD improves regional myocardial mechanics and might warrant consideration in the therapeutic approach for patients on HD.

Catestatin Protects Against Diastolic Dysfunction by Attenuating Mitochondrial Reactive Oxygen Species Generation.

Background Catestatin has been reported as a pleiotropic cardioprotective peptide. Heart failure with preserved ejection fraction (HFpEF) was considered a heterogeneous syndrome with a complex cause. We sought to investigate the role of catestatin in HFpEF and diastolic dysfunction. METHODS AND RESULTS Administration of recombinant catestatin (1.5 mg/kg/d) improved diastolic dysfunction and left ventricular chamber stiffness in transverse aortic constriction mice with deoxycorticosterone acetate pellet implantation, as reflected by Doppler tissue imaging and pressure-volume loop catheter. Less cardiac hypertrophy and myocardial fibrosis was observed, and transcriptomic analysis revealed downregulation of mitochondrial electron transport chain components after catestatin treatment. Catestatin reversed mitochondrial structural and respiratory chain component abnormality, decreased mitochondrial proton leak, and reactive oxygen species generation in myocardium. Excessive oxidative stress induced by Ru360 abolished catestatin treatment effects on HFpEF-like cardiomyocytes in vitro, indicating the beneficial role of catestatin in HFpEF as a mitochondrial ETC modulator. The serum concentration of catestatin was tested among 81 patients with HFpEF and 76 non-heart failure controls. Compared with control subjects, serum catestatin concentration was higher in patients with HFpEF and positively correlated with E velocity to mitral annular e' velocity ratio, indicating a feedback compensation role of catestatin in HFpEF. Conclusions Catestatin protects against diastolic dysfunction in HFpEF through attenuating mitochondrial electron transport chain-derived reactive oxygen species generation. Serum catestatin concentration is elevated in patients with HFpEF, probably as a relatively insufficient but self-compensatory mechanism.

SGLT2-i prevent left ventricular dysfunction induced by anthracycline in mouse model: A systematic-review and meta-analysis.

CLINICAL QUESTION: Could SGLT2-i be helpful for the prevention of left ventricular dysfunction induced by anthracycline? WHAT IS THE MAIN FINDING?: SGLT2-i appear effective for the prevention of left ventricular dysfunction induced by anthracycline in mouse model.

Echinochrome Prevents Sulfide Catabolism-Associated Chronic Heart Failure after Myocardial Infarction in Mice.

Abnormal sulfide catabolism, especially the accumulation of hydrogen sulfide (H2S) during hypoxic or inflammatory stresses, is a major cause of redox imbalance-associated cardiac dysfunction. Polyhydroxynaphtoquinone echinochrome A (Ech-A), a natural pigment of marine origin found in the shells and needles of many species of sea urchins, is a potent antioxidant and inhibits acute myocardial ferroptosis after ischemia/reperfusion, but the chronic effect of Ech-A on heart failure is unknown. Reactive sulfur species (RSS), which include catenated sulfur atoms, have been revealed as true biomolecules with high redox reactivity required for intracellular energy metabolism and signal transduction. Here, we report that continuous intraperitoneal administration of Ech-A (2.0 mg/kg/day) prevents RSS catabolism-associated chronic heart failure after myocardial infarction (MI) in mice. Ech-A prevented left ventricular (LV) systolic dysfunction and structural remodeling after MI. Fluorescence imaging revealed that intracellular RSS level was reduced after MI, while H2S/HS- level was increased in LV myocardium, which was attenuated by Ech-A. This result indicates that Ech-A suppresses RSS catabolism to H2S/HS- in LV myocardium after MI. In addition, Ech-A reduced oxidative stress formation by MI. Ech-A suppressed RSS catabolism caused by hypoxia in neonatal rat cardiomyocytes and human iPS cell-derived cardiomyocytes. Ech-A also suppressed RSS catabolism caused by lipopolysaccharide stimulation in macrophages. Thus, Ech-A has the potential to improve chronic heart failure after MI, in part by preventing sulfide catabolism.

Impact of right ventricular lead position on left ventricular functions and early remodeling in permanent single- and dual-chamber pacemakers.

BACKGROUND: Right ventricular (RV) apical pacing can induce both interventricular dyssynchrony and intraventricular dyssynchrony. Mechanical dyssynchrony after long-term RV apical pacing is associated with reduced left ventricular (LV) systolic function and deterioration in functional capacity. AIM: We aimed to identify the short-term effects of the pacemaker RV lead position on remodeling of LV systolic functions. PATIENTS AND METHODS: The study included 30 patients who presented with an indication of permanent pacing and who underwent permanent single- or dual-chamber pacemaker insertion: 15 patients with RV apical pacing (RV apex), and 15 patients with non-apical pacing (mid-septal). The two-dimensional (2D) speckle tracking imaging technique was used for quantification of global longitudinal function of the left ventricle and dyssynchrony evaluation before pacemaker implantation and after a 3-month follow-up. RESULTS: At the 3­month follow-up, post-pacing 2D speckle tracking echocardiography revealed impairment of global longitudinal strain in all patients and intraventricular dyssynchrony was significantly increased in the apical location compared with the non-apical location (radial dyssynchrony: 108.67 ± 11.68 ms vs. 80.53 ± 8.17 ms, p < 0.001) with a greater difference (50.53 ± 13.30 ms) in the apical location than in the non-apical location (29.87 ± 6.64 ms, p < 0.001). CONCLUSION: In the short-term follow-up, 2D speckle tracking echocardiography showed more radial dyssynchrony in the apical location than in the non-apical location of RV lead. The RV septal pacing is a better alternative in terms of less dyssynchrony compared to RV apical pacing. Older age, higher percentage of pacing, and device type are prognostic factors for development of pacemaker-induced cardiomyopathy.

Predictors of right ventricular pacing-induced left ventricular dysfunction in pacemaker recipients with preserved ejection fraction.

BACKGROUND: Pacing is an effective treatment in the management of patients with bradyarrhythmias. Chronic right ventricular pacing may cause electrical and mechanical dyssynchrony leading to a deterioration of left ventricular ejection fraction (LVEF). This deterioration of LVEF has been described as pacing-induced cardiomyopathy (PICM). The incidence of PICM has been described by many studies, ranging between 10% and 26%. Predictors for PICM are not yet established-studies were limited by variations in the definition of PICM and the follow-up period. The authors studied the incidence and predictors of PICM in patients with preserved LVEF who underwent pacemaker implantation. PATIENTS AND METHODS: This retrospective study included 320 patients that underwent single- or dual-chamber pacemaker implantation, with a mean follow up period of 4.7 ± 2.0 years. Implantable cardioverter defibrillator and cardiac resynchronization therapy patients were excluded from this study. Individuals that had a baseline LVEF ≥ 50% before implantation in transthoracic echocardiography were included in the study. RESULTS: Of the 320 patients included in the study, 45% were male, with a mean age 55.5 years. The incidence of PICM was 7.5%. Wider native QRS duration, particularly > 140 ms (P < 0.001), wider paced QRS (pQRS) duration > 150 ms (P < 0.001), low normal ejection fraction < 56% pre-implantation (P = 0.023) and increased LV end diastolic diameter (LVEDD) > 53 mm and LV end systolic diameter (LVESD) > 38 mm (P < 0.001) predicted the development of PICM. There was no association between burden of right ventricular pacing (P = 0.782) or pacing site (P = 0.876) and the development of pacemaker-induced cardiomyopathy. CONCLUSION: Right ventricular pacing-induced left ventricular dysfunction is not uncommon, with an incidence of 7.5%. Wider native and paced QRS durations, low normal ejection fraction (< 56%) pre-implantation and increased LVEDD and LVESD post implantation are the most important predictors for the development of PICM.

Rationale and Design of the Cardiac CARE Trial: A Randomized Trial of Troponin-Guided Neurohormonal Blockade for the Prevention of Anthracycline Cardiotoxicity.

BACKGROUND: Anthracyclines are effective cytotoxic drugs used in the treatment of breast cancer and lymphoma but are associated with myocardial injury, left ventricular dysfunction, and heart failure. Anthracycline-induced cardiotoxicity is highly variable in severity and without a proven therapeutic intervention. ß-Adrenergic receptor blockers and renin-angiotensin-system inhibitor therapies have been associated with modest cardioprotective effects in unselected patients. METHODS: The Cardiac CARE trial is a multicentre prospective randomized open-label blinded end point trial of combination ß-adrenergic receptor blocker and renin-angiotensin-system inhibitor therapy in patients with breast cancer and non-Hodgkin lymphoma receiving anthracycline chemotherapy that is associated with myocardial injury. Patients at higher risk of cardiotoxicity with plasma high-sensitivity cTnI (cardiac troponin I) concentrations in the upper tertile at the end of chemotherapy are randomized to standard of care plus combination candesartan and carvedilol therapy or standard of care alone. All patients undergo cardiac magnetic resonance imaging before and 6 months after anthracycline treatment. The primary end point is the change in left ventricular ejection fraction at 6 months after chemotherapy. In low-risk nonrandomized patients, left ventricular ejection fraction before and 6 months after anthracycline will be compared with define the specificity of the high-sensitivity cTnI assay for identifying low-risk participants who do not develop left ventricular systolic dysfunction. DISCUSSION: Cardiac CARE will examine whether cardiac biomarker monitoring identifies patients at risk of left ventricular dysfunction following anthracycline chemotherapy and whether troponin-guided treatment with combination candesartan and carvedilol therapy prevents the development of left ventricular dysfunction in these high-risk patients.

Ellagic acid prevents myocardial infarction-induced left ventricular diastolic dysfunction in ovariectomized rats.

Estrogen deficiency is associated with increased oxidative stress, which can contribute to left ventricular diastolic dysfunction (LVDD). We hypothesized that oral treatment with ellagic acid (EA), a potent and natural antioxidant compound, can improve MI-induced LVDD in ovariectomized rats, by reducing the formation of reactive oxygen species. Ovariectomized rats MI-induced LVDD followed by treatment with vehicle (DD) or EA (DD + EA) for 4 weeks. Non-LVDD-induced rats treated with vehicle (S) or EA (S + EA) were used as controls. Left ventricular systolic pressure; left ventricular end-diastolic pressure (LVEDP); maximum rate of pressure rise: +dP/dt and fall: -dP/dt) were evaluated in all animals after treatment. Left ventricle superoxide anion formation was quantified in situ by fluorescence. Phospho-CAMKII, SOD2, catalase, and gp91-phox abundances were evaluated by Western blot analyses. SOD (superoxide dismutase) and catalase activities were measured by spectrophotometry. The results showed that the LVEDP was significantly increased in both DD and DD + EA groups compared to S and S + EA. However, LVEDP in the DD + EA group was significantly decreased compared to DD, indicating an EA-mediated effect. In the DD group, superoxide production and gp91-phox protein abundance were increased while SOD2 abundance was decreased when compared to the S and S + EA groups. An increase in SOD activity was also observed in the DD + EA group. EA treatment reduced CaMKII phosphorylation in the DD + EA group compared to the DD. We concluded that EA treatment attenuated diastolic dysfunction in our experimental model, via reduction of reactive oxygen species and CaMKII activity, indicating EA as a promising natural therapeutic option for cardiac dysfunction.

Septal flash correction with His-Purkinje pacing predicts echocardiographic response in resynchronization therapy.

BACKGROUND: His-Purkinje conduction system pacing (HPCSP) has been proposed as an alternative to Cardiac Resynchronization Therapy (CRT); however, predictors of echocardiographic response have not been described in this population. Septal flash (SF), a fast contraction and relaxation of the septum, is a marker of intraventricular dyssynchrony. METHODS: The study aimed to analyze whether HPCSP corrects SF in patients with CRT indication, and if correction of SF predicts echocardiographic response. This retrospective analysis of prospectively collected data included 30 patients. Left ventricular ejection fraction (LVEF) was measured with echocardiography at baseline and at 6-month follow-up. Echocardiographic response was defined as increase in five points in LVEF. RESULTS: HPCSP shortened QRS duration by 48 ± 21 ms and SF was significantly decreased (baseline 3.6 ± 2.2 mm vs. HPCSP 1.5 ± 1.5 mm p < .0001). At 6-month follow-up, mean LVEF improvement was 8.6% ± 8.7% and 64% of patients were responders. There was a significant correlation between SF correction and increased LVEF (r = .61, p = .004). A correction of ≥1.5 mm (baseline SF - paced SF) had a sensitivity of 81% and 80% specificity to predict echocardiographic response (area under the curve 0.856, p = .019). CONCLUSION: HPCSP improves intraventricular dyssynchrony and results in 64% echocardiographic responders at 6-month follow-up. Dyssynchrony improvement with SF correction may predict echocardiographic response at 6-month follow-up.

A systematic review and meta-analysis of beta-blockers and renin-angiotensin system inhibitors for preventing left ventricular dysfunction due to anthracyclines or trastuzumab in patients with breast cancer.

AIMS: Trastuzumab and anthracyclines, often used in the treatment of breast cancer, may impair myocardial function, and reduce left ventricular ejection fraction (LVEF), potentially causing heart failure. Randomized controlled trials (RCTs) have evaluated the effects of beta-blockers (BBs), angiotensin receptor blockers (ARBs), and angiotensin-converting enzyme inhibitors (ACEI) on trastuzumab- and anthracycline-associated cardiotoxicity. We report a meta-analysis of these RCTs in patients with breast cancer. METHODS AND RESULTS: The primary analysis was on the effect of BBs and ACEI/ARBs on LVEF in patients treated with either trastuzumab or anthracyclines. A secondary analysis was done investigating the effect of BBs or ACEI/ARBs on LVEF in trastuzumab and anthracycline treatments. Only RCTs were included using the search term 'ARBs, ACEIs, BBs, anthracyclines, trastuzumab, and breast cancer' in PubMed, Embase, and CENTRAL up to 31 March 2021. A meta-analysis was conducted to estimate the mean difference (MD) in LVEF between intervention and placebo groups at follow-up. A total of nine RCTs (n = 1362) were included in the analysis. All patients were women. BBs and ACEI/ARBs were shown to attenuate the decline in LVEF during trastuzumab and anthracycline treatments [MD: 2.4; 95% confidence interval (CI): 0.3-4.2 and MD: 1.5; 95% CI: -0.6 to 3.7]. Compared with placebo, LVEF was significantly higher in patients assigned to BB or ACEI/ARB on trastuzumab (MD: 2.3; 95% CI: 0.0-4.6) but not on anthracyclines (MD: 1.9; 95% CI: -0.5 to 4.2). CONCLUSION: Both BB and ACEI/ARB therapies were associated with the preservation of LVEF during trastuzumab and anthracycline-containing regimens as compared with placebo, suggesting both to be beneficial.

Vitamin D3 Supplementation Alleviates Left Ventricular Dysfunction in a Mouse Model of Diet-Induced Type 2 Diabetes: Potential Involvement of Cardiac Lipotoxicity Modulation.

PURPOSE: To evaluate the effectiveness of vitamin D3 supplementation, in secondary prevention, on cardiac remodeling and function, as well as lipid profile, in a mouse model of diet-induced type 2 diabetes. METHODS: Mice were fed a high fat and sucrose diet for 10 weeks. Afterward, diet was maintained for 15 more weeks and two groups were formed, with and without cholecalciferol supplementation. A control group was fed with normal chow. Glucose homeostasis and cardiac function were assessed at baseline and at the 10th and 24th weeks. Animals were killed at the 10th and 25th weeks for plasma and cardiac sample analysis. Cardiac lipid profile was characterized by LC-MS/MS. RESULTS: After 10 weeks of diet, mice exhibited pre-diabetes, mild left ventricle hypertrophy, and impaired longitudinal strain, but preserved myocardial circumferential as well as global diastolic and systolic cardiac function. After 15 more weeks of diet, animals presented with well-established type 2 diabetes, pathological cardiac hypertrophy, and impaired regional myocardial function. Cholecalciferol supplementation had no effect on glucose homeostasis but improved cardiac remodeling and regional myocardial function. After 25 weeks, non-supplemented mice exhibited increased myocardial levels of ceramides and diacylglycerol, both of which were normalized by vitamin D3 supplementation. CONCLUSION: This work brought to light the beneficial effects of cholecalciferol supplementation, in secondary prevention, on cardiac remodeling and function in a mouse model of diet-induced type 2 diabetes. Those cardioprotective effects may be, at least in part, attributed to the modulation of myocardial levels of lipotoxic species by vitamin D.

Personalised reprogramming to prevent progressive pacemaker-related left ventricular dysfunction: A phase II randomised, controlled clinical trial.

BACKGROUND: Pacemakers are widely utilised to treat bradycardia, but right ventricular (RV) pacing is associated with heightened risk of left ventricular (LV) systolic dysfunction and heart failure. We aimed to compare personalised pacemaker reprogramming to avoid RV pacing with usual care on echocardiographic and patient-orientated outcomes. METHODS: A prospective phase II randomised, double-blind, parallel-group trial in 100 patients with a pacemaker implanted for indications other than third degree heart block for ≥2 years. Personalised pacemaker reprogramming was guided by a published protocol. Primary outcome was change in LV ejection fraction on echocardiography after 6 months. Secondary outcomes included LV remodeling, quality of life, and battery longevity. RESULTS: Clinical and pacemaker variables were similar between groups. The mean age (SD) of participants was 76 (+/-9) years and 71% were male. Nine patients withdrew due to concurrent illness, leaving 91 patients in the intention-to-treat analysis. At 6 months, personalised programming compared to usual care, reduced RV pacing (-6.5±1.8% versus -0.21±1.7%; p<0.01), improved LV function (LV ejection fraction +3.09% [95% confidence interval (CI) 0.48 to 5.70%; p = 0.02]) and LV dimensions (LV end systolic volume indexed to body surface area -2.99mL/m2 [95% CI -5.69 to -0.29; p = 0.03]). Intervention also preserved battery longevity by approximately 5 months (+0.38 years [95% CI 0.14 to 0.62; p<0.01)) with no evidence of an effect on quality of life (+0.19, [95% CI -0.25 to 0.62; p = 0.402]). CONCLUSIONS: Personalised programming in patients with pacemakers for bradycardia can improve LV function and size, extend battery longevity, and is safe and acceptable to patients. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT03627585.

Nicotinamide mononucleotide attenuates doxorubicin-induced cardiotoxicity by reducing oxidative stress, inflammation and apoptosis in rats.

Doxorubicin (DOX) is an effective and widely used antineoplastic drug. However, its clinical application is limited due to its dose-dependent cardiotoxicity. Great efforts have been made to explore the pathological mechanism of DOX-induced cardiotoxicity (DIC), but new drugs and strategies to alleviate cardiac damage are still needed. Here, we aimed to investigate the effect of nicotinamide mononucleotide (NMN) on DIC in rats. The results of the present study showed that DOX treatment significantly induced cardiac dysfunction and cardiac injury, whereas NMN alleviated these changes. In addition, NMN inhibited Dox-induced activation of nucleotide-binding domain-like receptor protein 3 (NLRP3) inflammasome-mediated inflammation, as evidenced by decreased caspase 1 and IL-1ß activity. Moreover, NMN treatment increased glutathione (GSH) levels and superoxide dismutase (SOD) activity and decreased the levels of malondialdehyde (MDA) and reactive oxygen species (ROS) in DOX-treated rats. Furthermore, NMN treatment mitigated DOX-induced cardiomyocyte apoptosis and cardiac fibrosis. In conclusion, the results indicated that NMN protects against DIC in rats by inhibiting NLRP3 inflammasome activation, oxidative stress, and apoptosis.

HMG-CoA Reductase Inhibitor, Simvastatin Is Effective in Decreasing Degree of Myocarditis by Inhibiting Metalloproteinases Activation.

BACKGROUND: Acute myocarditis often progresses to heart failure because there is no effective, etiology-targeted therapy of this disease. Simvastatin has been shown to be cardioprotective by decreasing matrix metalloproteinases' (MMPs) activity. The study was designed to determine whether simvastatin inhibits MMPs activity, decreases the severity of inflammation and contractile dysfunction of the heart in experimental autoimmune myocarditis (EAM). METHODS: Simvastatin (3 or 30 mg/kg/day) was given to experimental rats with EAM by gastric gavage for 21 days. Then transthoracic echocardiography was performed, MMPs activity and troponin I level were determined and tissue samples were assessed under a light and transmission electron microscope. RESULTS: Hearts treated with simvastatin did not show left ventricular enlargement. As a result of EAM, there was an enhanced activation of MMP-9, which was significantly reduced in the high-dose simvastatin group compared to the low-dose group. It was accompanied by prevention of myofilaments degradation and reduction of severity of inflammation. CONCLUSIONS: The cardioprotective effects of simvastatin in the acute phase of EAM are, at least in part, due to its ability to decrease MMP-9 activity and subsequent decline in myofilaments degradation and suppression of inflammation. These effects were achieved in doses equivalent to therapeutic doses in humans.

Prodrug of ICRF-193 provides promising protective effects against chronic anthracycline cardiotoxicity in a rabbit model in vivo.

The anthracycline (ANT) anticancer drugs such as doxorubicin or daunorubicin (DAU) can cause serious myocardial injury and chronic cardiac dysfunction in cancer survivors. A bisdioxopiperazine agent dexrazoxane (DEX) has been developed as a cardioprotective drug to prevent these adverse events, but it is uncertain whether it is the best representative of the class. The present study used a rabbit model of chronic ANT cardiotoxicity to examine another bisdioxopiperazine compound called GK-667 (meso-(butane-2,3-diylbis(2,6-dioxopiperazine-4,1-diyl))bis(methylene)-bis(2-aminoacetate) hydrochloride), a water-soluble prodrug of ICRF-193 (meso-4,4'-(butan-2,3-diyl)bis(piperazine-2,6-dione)), as a potential cardioprotectant. The cardiotoxicity was induced by DAU (3 mg/kg, intravenously, weekly, 10 weeks), and GK-667 (1 or 5 mg/kg, intravenously) was administered before each DAU dose. The treatment with GK-667 was well tolerated and provided full protection against DAU-induced mortality and left ventricular (LV) dysfunction (determined by echocardiography and LV catheterization). Markers of cardiac damage/dysfunction revealed minor cardiac damage in the group co-treated with GK-667 in the lower dose, whereas almost full protection was achieved with the higher dose. This was associated with similar prevention of DAU-induced dysregulation of redox and calcium homeostasis proteins. GK-667 dose-dependently prevented tumor suppressor p53 (p53)-mediated DNA damage response in the LV myocardium not only in the chronic experiment but also after single DAU administration. These effects appear essential for cardioprotection, presumably because of the topoisomerase IIß (TOP2B) inhibition provided by its active metabolite ICRF-193. In addition, GK-667 administration did not alter the plasma pharmacokinetics of DAU and its main metabolite daunorubicinol (DAUol) in rabbits in vivo. Hence, GK-667 merits further investigation as a promising drug candidate for cardioprotection against chronic ANT cardiotoxicity.

Targeting mitochondrial reactive oxygen species-mediated oxidative stress attenuates nicotine-induced cardiac remodeling and dysfunction.

Long-term nicotine intake is associated with an increased risk of myocardial damage and dysfunction. However, it remains unclear whether targeting mitochondrial reactive oxygen species (ROS) prevents nicotine-induced cardiac remodeling and dysfunction. This study investigated the effects of mitoTEMPO (a mitochondria-targeted antioxidant), and resveratrol (a sirtuin activator) , on nicotine-induced cardiac remodeling and dysfunction. Sprague-Dawley rats were administered 0.6 mg/kg nicotine daily with 0.7 mg/kg mitoTEMPO, 8 mg/kg resveratrol, or vehicle alone for 28 days. At the end of the study, rat hearts were collected to analyze the cardiac structure, mitochondrial ROS level, oxidative stress, and inflammation markers. A subset of rat hearts was perfused ex vivo to determine the cardiac function and myocardial susceptibility to ischemia-reperfusion injury. Nicotine administration significantly augmented mitochondrial ROS level, cardiomyocyte hypertrophy, fibrosis, and inflammation in rat hearts. Nicotine administration also induced left ventricular dysfunction, which was worsened by ischemia-reperfusion in isolated rat hearts. MitoTEMPO and resveratrol both significantly attenuated the adverse cardiac remodeling induced by nicotine, as well as the aggravation of postischemic ventricular dysfunction. Findings from this study show that targeting mitochondrial ROS with mitoTEMPO or resveratrol partially attenuates nicotine-induced cardiac remodeling and dysfunction.

Angiotensin-(1-7) protects against sepsis-associated left ventricular dysfunction induced by lipopolysaccharide.

Sepsis-induced myocardial dysfunction is a major cause of death. The present study explored whether angiotensin (Ang)-(1-7), an important biologically active peptide of the renin-angiotensin system, could improve cardiac dysfunction and attenuate inflammation and apoptosis. Experiments were carried out in mice and in neonatal rat cardiomyocytes (NRCMs) treated with lipopolysaccharide (LPS) or Ang-(1-7). Angiotensin converting enzyme 2 (ACE2), Ang-(1-7) and Mas receptor (MasR) expressions were reduced in the mouse left ventricular and NRCM treated with LPS. Ang-(1-7) increased the ejection fraction and fractional shortening of left ventricular, which were reduced upon LPS injection in mice. Ang-(1-7) pre-treatment reversed LPS-induced decreases of α-myosin heavy chain (MHC) and ß-MHC, and increases of S100 calcium binding protein A8 (S100A8) and S100A9 in the mouse left ventricular. The LPS-induced increases of tumor necrosis factor (TNF)-α and interleukin (IL)-1ß in the mouse left ventricular and NRCMs were inhibited by Ang-(1-7) administration. Ang-(1-7) treatment reversed the increases of cleaved-caspase 3, cleaved-caspase 8 and Bax, and the decrease of Bcl2 induced by LPS in the mouse left ventricular and NRCMs. The increases of MAPKs pathway induced by LPS in NRCMs were inhibited by Ang-(1-7). These results indicate that Ang-(1-7) protects against sepsis-associated left ventricular dysfunction induced by LPS, and increases cardiac contractility via attenuating inflammation and apoptosis.

Effects of Sodium-Glucose Linked Transporter 2 Inhibition With Ertugliflozin on Mitochondrial Function, Energetics, and Metabolic Gene Expression in the Presence and Absence of Diabetes Mellitus in Mice.

Background Inhibitors of the sodium-glucose linked transporter 2 improve cardiovascular outcomes in patients with or without type 2 diabetes mellitus, but the effects on cardiac energetics and mitochondrial function are unknown. We assessed the effects of sodium-glucose linked transporter 2 inhibition on mitochondrial function, high-energy phosphates, and genes encoding mitochondrial proteins in hearts of mice with and without diet-induced diabetic cardiomyopathy. Methods and Results Mice fed a control diet or a high-fat, high-sucrose diet received ertugliflozin mixed with the diet (0.5 mg/g of diet) for 4 months. Isolated mitochondria were assessed for functional capacity. High-energy phosphates were assessed by 31P nuclear magnetic resonance spectroscopy concurrently with contractile performance in isolated beating hearts. The high-fat, high-sucrose diet caused myocardial hypertrophy, diastolic dysfunction, mitochondrial dysfunction, and impaired energetic response, all of which were prevented by ertugliflozin. With both diets, ertugliflozin caused supernormalization of contractile reserve, as measured by rate×pressure product at high work demand. Likewise, the myocardial gene sets most enriched by ertugliflozin were for oxidative phosphorylation and fatty acid metabolism, both of which were enriched independent of diet. Conclusions Ertugliflozin not only prevented high-fat, high-sucrose-induced pathological cardiac remodeling, but improved contractile reserve and induced the expression of oxidative phosphorylation and fatty acid metabolism gene sets independent of diabetic status. These effects of sodium-glucose linked transporter 2 inhibition on cardiac energetics and metabolism may contribute to improved structure and function in cardiac diseases associated with mitochondrial dysfunction, such as heart failure.