Angiotensin receptor-neprilysin inhibitor attenuates cardiac hypertrophy and improves diastolic dysfunction in a mouse model of heart failure with preserved ejection fraction.

LCZ696, an angiotensin receptor-neprilysin inhibitor, has shown promising clinical efficacy in patients with heart failure (HF) with reduced ejection fraction. However, its potential effects on heart failure with preserved ejection fraction (HFpEF) are still not fully understood. We evaluated the effect of LCZ696 on HFpEF in transverse aortic constriction mice and compared it with the effect of the angiotensin receptor blocker, valsartan. We found that LCZ696 improved cardiac diastolic function by reducing ventricular hypertrophy and fibrosis in mice with overload-induced diastolic dysfunction. In addition, there was superior inhibition of LCZ696 than stand-alone valsartan. As a potential underlying mechanism, we demonstrated that LCZ696 behaves as a potent suppressor of calcium-mediated calcineurin-nuclear factor of activated T cells (NFAT) signalling transduction pathways. Hence, we demonstrated the protective effects of LCZ696 in overload-induced HFpEF and provided a pharmaceutical therapeutic strategy for related diseases.

Initial experience with del Nido cardioplegia solution at a Pediatric and Congenital Cardiac Surgery Program in Brazil.

OBJECTIVE: The aim of this study was to evaluate outcome measures between our standard multidose cardioplegia protocol and a del Nido cardioplegia protocol in congenital heart surgery patients. METHODS: Retrospective single-center study including 250 consecutive patients that received del Nido cardioplegia (DN group) with a mandatory reperfusion period of 30% of cross clamp time and 250 patients that received a modified St. Thomas' solution (ST group). Groups were matched by age, weight, gender, and Risk Adjustment for Congenital Heart Surgery (RACHS-1) scores. Preoperative hematocrit and oxygen saturation were also recorded. Outcomes analyzed were the vasoactive inotropic score (VIS), lactate, ventilation time, ventricular dysfunction with low cardiac output syndrome (LCOS), intensive care unit (ICU) length of stay (LOS), hospital LOS, bypass and aortic cross-clamp times, and in-hospital mortality. RESULTS: Both groups were comparable demographically. Statistically significant differences (p ⩽ 0.05) were noted for cardiac dysfunction with LCOS, hematocrit at end of surgery (p = 0.0038), VIS on ICU admission and at end of surgery (p = 0.0111), and ICU LOS (p = 0.00118) with patients in the DN group having more desirable values for those parameters. Other outcome measures did not reach statistical significance. CONCLUSION: In our congenital cardiac surgery population, del Nido cardioplegia strategy was associated with less ventricular dysfunction with LCOS, a lower VIS and decreased ICU LOS compared with patients that received our standard myocardial protection using a modified St. Thomas' solution. Despite the limitation of this study, including its retrospective nature and cohort size, these data supported our transition to incorporate del Nido cardioplegia solution with a mandatory reperfusion period as the preferred myocardial protection method in our program.

Congenital diaphragmatic hernia-associated cardiac dysfunction.

There is increasing evidence that cardiac dysfunction is a key contributor to CDH pathophysiology. Dysfunction in both right and left ventricles is common in the early neonatal period, contributes to clinical disease severity, and is associated with adverse outcomes including death and ECMO use. Early and routine assessment of ventricular function and pulmonary artery pressure may guide individualized clinical decision-making, including use of pulmonary vasodilators, cardiotropes, ECMO, and timing of surgical repair. Minimizing cardiac dysfunction, whether by prenatal, postnatal or perinatal treatment strategies, may lead to improved outcome in CDH.

Valproic acid attenuates sepsis-induced myocardial dysfunction in rats by accelerating autophagy through the PTEN/AKT/mTOR pathway.

AIMS: Sepsis is a leading cause of death and disability worldwide. Autophagy may play a protective role in sepsis-induced myocardial dysfunction (SIMD). The present study investigated whether valproic acid (VPA), a class I histone deacetylase (HDAC) inhibitor, can attenuate SIMD by accelerating autophagy. MAIN METHODS: A sepsis model was established via the cecum ligation and puncture of male Sprague-Dawley rats. Cardiac injuries were measured using serum markers, echocardiographic cardiac parameters, and hematoxylin and eosin staining. Cardiac mitochondria injuries were detected with transmission electron microscopy, adenosine triphosphate (ATP) and cardiac mitochondrial DNA (mtDNA) contents. Cardiac oxidative levels were measured using redox markers in the cardiac homogenate. Real-time polymerase chain reaction (RT-PCR) and Western blot were performed to detect the expression levels of relative genes and proteins. HDAC binding to the phosphatase and tensin homolog deleted on chromosome ten (PTEN) promoters and histone acetylation levels of the PTEN promoters were analyzed via chromatin immunoprecipitation and quantitative RT-PCR. KEY FINDINGS: VPA can ameliorate SIMD by enhancing the autophagy level of the myocardium to reduce mitochondrial damage, oxidative stress, and myocardial inflammation in septic rats. Moreover, this study demonstrated that VPA induces autophagy by inhibiting HDAC1- and HDAC3-mediated PTEN expression in the myocardial tissues of septic rats. SIGNIFICANCE: This study found that VPA attenuates SIMD through myocardial autophagy acceleration by increasing PTEN expression and inhibiting the AKT/mTOR pathway. These findings preliminarily suggest that VPA may be a potential approach for the intervention and treatment of SIMD.

Sacubitril/valsartan in chronic kidney disease, the nephrologist point of view. / Experiencia clínica con sacubitrilo/valsartán en pacientes con insuficiencia renal: la visión del nefrólogo.

BACKGROUND AND OBJECTIVES: Sacubitril/valsartan reduces cardiovascular morbidity and mortality in patients with systolic dysfunction. The aim of the present study was to assess the evolution of chronic kidney disease (CKD) patients after initiating sacubitril/valsartan. MATERIAL AND METHODS: We included 66 consecutive CKD patients with systolic dysfunction followed up in outpatient care. Patients had to meet the inclusion criteria of having a New York Heart Association class ii to iv, receiving maximum tolerated doses of optimal medical therapy and CKD stages 1 to 4. At baseline, comorbidities and epidemiological data were collected and low doses of sacubitril/valsartan were initiated. At month 1 and 3, doses of sacubitril/valsartan were increased up to the maximum doses if tolerated. In each visit, renal function and cardiac biomarkers were recorded. All the data were analyzed at the end of follow up (6 months). RESULTS: Of the 66 patients, 42 (63%) were men, with a mean age of 73±15 years. Mean creatinine at baseline was 1.42±0.5 mg/dL (glomerular filtration rate estimated by CKD-EPI was 50±19 mL/min/1.73 m2) and mean left ventricular ejection fraction (LVEF) was 31±9%. At the end of follow up, LVEF improved from 31±9% to 39±15% (P <0.001). After one month of treatment, renal function improved up to 53±21 mL/min/1.73 m2, P=0.005. For the remaining follow-up time, glomerular filtration rate remained stable (mean at end of follow-up 51±18 mL/min/1.73 m2). Seven patients (10.6%) withdrew from treatment. CONCLUSION: In our experience, sacubitril/valsartan is safe in CKD, offering stability in CKD progression after 6 months.

1,2,3,4,6-Penta-O-galloyl-ß-d-glucose modulates perivascular inflammation and prevents vascular dysfunction in angiotensin II-induced hypertension.

BACKGROUND AND PURPOSE: Hypertension is a multifactorial disease, manifested by vascular dysfunction, increased superoxide production, and perivascular inflammation. In this study, we have hypothesized that 1,2,3,4,6-penta-O-galloyl-ß-d-glucose (PGG) would inhibit vascular inflammation and protect from vascular dysfunction in an experimental model of hypertension. EXPERIMENTAL APPROACH: PGG was administered to mice every 2 days at a dose of 10 mg·kg-1 i.p during 14 days of Ang II infusion. It was used at a final concentration of 20 µM for in vitro studies in cultured cells. KEY RESULTS: Ang II administration increased leukocyte and T-cell content in perivascular adipose tissue (pVAT), and administration of PGG significantly decreased total leukocyte and T-cell infiltration in pVAT. This effect was observed in relation to all T-cell subsets. PGG also decreased the content of T-cells bearing CD25, CCR5, and CD44 receptors and the expression of both monocyte chemoattractant protein 1 (CCL2) in aorta and RANTES (CCL5) in pVAT. PGG administration decreased the content of TNF+ and IFN-γ+ CD8 T-cells and IL-17A+ CD4+ and CD3+ CD4- CD8- cells. Importantly, these effects of PGG were associated with improved vascular function and decreased ROS production in the aortas of Ang II-infused animals independently of the BP increase. Mechanistically, PGG (20 µM) directly inhibited CD25 and CCR5 expression in cultured T-cells. It also decreased the content of IFN-γ+ CD8+ and CD3+ CD4- CD8- cells and IL-17A+ CD3+ CD4- CD8- cells. CONCLUSION AND IMPLICATION: PGG may constitute an interesting immunomodulating strategy in the regulation of vascular dysfunction and hypertension. LINKED ARTICLES: This article is part of a themed section on Immune Targets in Hypertension. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.12/issuetoc.

Role of renin-angiotensin system antagonists in the prevention of bevacizumab- and sunitinib-mediated cardiac dysfunction.

Although anticancer systemic therapy agents clearly lead to improved survival in patients with cancer, these can come at the cost of serious complications including cardiotoxicity. Two types of targeted systemic therapies currently in use for colorectal cancer (CRC) and renal cell cancer (RCC), respectively, include the vascular endothelial growth factor inhibitor bevacizumab (BVZ) and the tyrosine kinase inhibitor sunitinib (SNT). Despite the beneficial effects of BVZ and SNT in improving clinical outcomes in the settings of CRC and RCC, there is an increased risk of cardiac dysfunction. The aim of the present study was to determine whether prophylactic administration of renin-angiotensin system (RAS) inhibitors would attenuate the cardiotoxic side effects of BVZ or SNT in a chronic in vivo murine model. A total of 194 wild-type C57Bl/6 male mice received: 1) 0.9% saline, 2) BVZ (10 mg·kg-1·wk-1), or 3) SNT (40 mg·kg-1·day-1) for 4 wk. Within each arm, mice received daily prophylactic treatment with hydralazine (0.05 mg/ml), aliskiren (50 mg/kg), perindopril (4 mg/kg), or valsartan (2 mg/kg). Although hydralazine effectively lowered blood pressure in BVZ- or SNT-treated mice, it did not prevent left ventricular systolic dysfunction. Prophylactic administration of aliskiren, perindopril, or valsartan prevented adverse cardiovascular remodeling in mice treated with either BVZ or SNT. The addition of RAS antagonists also downregulated expression of phosphorylated p38 and Bcl-2-like 19-kDa interacting protein 3 in SNT-treated mice. In our chronic in vivo murine model, RAS antagonists partially attenuated the development of BVZ- or SNT-mediated cardiac dysfunction. Future clinical studies are warranted to investigate the cardioprotective effects of prophylactic treatment with RAS inhibitors in the settings of CRC and RCC. NEW & NOTEWORTHY In the evolving field of cardio-oncology, bevacizumab and sunitinib improve clinical outcomes in the settings of metastatic colorectal cancer and renal cell cancer, respectively. These anticancer drugs, however, are associated with an increased risk of cardiotoxicity. The prophylactic administration of renin-angiotensin system antagonists is partially cardioprotective against bevacizumab- and sunitinib-mediated cardiac dysfunction.

The ACE 2 activator diminazene aceturate (DIZE) improves left ventricular diastolic dysfunction following myocardial infarction in rats.

Diminazene aceturate (DIZE) has been reported to enhance the catalytic efficiency of ACE-2 and presumably increases angiotensin 1-7 generation, interfering with cardiac remodeling after myocardial infarction (MI). Our aim was to investigate the chronic effects of DIZE on cardiac dysfunction post-MI. Male Wistar rats underwent myocardial infarction (MI) or SHAM surgery (SO) and were divided into groups treated with DIZE 15 mg/kg/day, s.c. or vehicle (Control). After 4 weeks, the hemodynamic variables were recorded by cardiac catheterism. Hearts were then arrested to obtain the left ventricular (LV) pressure-volume curves in situ. Cardiomyocyte hypertrophy and collagen content were determined by histology. DIZE prevented LV end-diastolic pressure increases in MI rats (MI: 26 ± 3.3 vs. MI-DIZE: 15 ± 1.6 mmHg, P < 0.001) without a significant effect on LV systolic pressure (LVSP). Moreover, DIZE improved LV contractility (+dP/dt, MI: 3014 ± 161 vs. MI-DIZE: 3884 ± 104 mmHg/s, P < 0.001) and relaxation (-dP/dt, MI: -2333 ± 91 vs. MI-DIZE: -2798 ± 120 mmHg/s, P < 0.05). Right ventricular SP was increased in the MI compared to that in the SO group (40 ± 0.6 vs. 30 ± 1.2 mmHg; P < 0.01), and DIZE partially prevented this augmentation. LV stiffness was reduced in MI-DIZE compared with that in MI (0.64 ± 0.01 vs. 0.78 ± 0.02 mmHg/mL; P < 0.01). DIZE treatment reduced the interstitial collagen content by 18% in the surviving LV myocardium. Cardiomyocyte hypertrophy remained unaffected by DIZE treatment. Our findings show that chronic DIZE treatment post-MI attenuates the morphofunctional changes induced by MI in rats. The effects on LV -dP/dt, chamber stiffness and collagen content suggest this drug can be used as a therapeutic agent to reduce interstitial fibrosis and diastolic dysfunction after MI.

Sildenafil ameliorates right ventricular early molecular derangement during left ventricular pressure overload.

Right ventricular (RV) dysfunction following left ventricular (LV) failure is associated with poor prognosis. RV remodeling is thought initiated by the increase in the afterload of RV due to secondary pulmonary hypertension (PH) to impaired LV function; however, RV molecular changes might occur in earlier stages of the disease. cGMP (cyclic guanosine monophosphate)-phosphodiesterase 5 (PDE5) inhibitors, widely used to treat PH through their pulmonary vasorelaxation properties, have shown direct cardiac benefits, but their impacts on the RV in LV diseases are not fully determined. Here we show that RV molecular alterations occur early in the absence of RV hemodynamic changes during LV pressure-overload and are ameliorated by PDE5 inhibition. Two-day moderate LV pressure-overload (transverse aortic constriction) neither altered RV pressure/ function nor RV weight in mice, while it induced only mild LV hypertrophy. Importantly, pathological molecular features were already induced in the RV free wall myocardium, including up-regulation of gene markers for hypertrophy and inflammation, and activation of extracellular signal-regulated kinase (ERK) and calcineurin. Concomitant PDE5 inhibition (sildenafil) prevented induction of such pathological genes and activation of ERK and calcineurin in the RV as well as in the LV. Importantly, dexamethasone also prevented these RV molecular changes, similarly to sildenafil treatment. These results suggest the contributory role of inflammation to the early pathological interventricular interaction between RV and LV. The current study provides the first evidence for the novel early molecular cross-talk between RV and LV, preceding RV hemodynamic changes in LV disease, and supports the therapeutic strategy of enhancing cGMP signaling pathway to treat heart diseases.

Treatment with Fenofibrate plus a low dose of Benznidazole attenuates cardiac dysfunction in experimental Chagas disease.

Trypanosoma cruzi induces serious cardiac alterations during the chronic infection. Intense inflammatory response observed from the beginning of infection, is critical for the control of parasite proliferation and evolution of Chagas disease. Peroxisome proliferator-activated receptors (PPAR)-α, are known to modulate inflammation. In this study we investigated whether a PPAR-α agonist, Fenofibrate, improves cardiac function and inflammatory parameters in a murine model of T. cruzi infection. BALB/c mice were sequentially infected with two T. cruzi strains of different genetic background. Benznidazole, commonly used as trypanocidal drug, cleared parasites but did not preclude cardiac pathology, resembling what is found in human chronic chagasic cardiomyopathy. Fenofibrate treatment restored to normal values the ejection and shortening fractions, left ventricular end-diastolic, left ventricular end-systolic diameter, and isovolumic relaxation time. Moreover, it reduced cardiac inflammation and fibrosis, decreased the expression of pro-inflammatory (IL-6, TNF-α and NOS2) and heart remodeling mediators (MMP-9 and CTGF), and reduced serum creatine kinase activity. The fact that Fenofibrate partially inhibited NOS2 expression and NO release in the presence of a PPAR-α non-competitive inhibitor, suggested it also acted through PPAR-α-independent pathways. Since IκBα cytosolic degradation was inhibited by Fenofibrate, it can be concluded that the NFκB pathway has a role in its effects. Thus, we demonstrate that Fenofibrate acts through PPAR-α-dependent and -independent pathways. Our study shows that combined treatment with Fenofibrate plus Benznidazole is able both to reverse the cardiac dysfunction associated with the ongoing inflammatory response and fibrosis and to attain parasite clearance in an experimental model of Chagas disease.

LCZ696 improves cardiac function via alleviating Drp1-mediated mitochondrial dysfunction in mice with doxorubicin-induced dilated cardiomyopathy.

AIMS: LCZ696, a novel angiotensin receptor neprilysin inhibitor, is effective in treating heart failure patients. Doxorubicin (DOX) is an effective antitumor medication but the cardiotoxicity limited its clinical use. In this study, we aimed to determine the effect of LCZ696 on DOX-induced cardiomyopathy in mice and in vitro and to explore related mechanisms focusing on fission protein dynamin-related protein 1 (Drp1). METHODS AND RESULTS: In human study, we found that myocardial fission protein Drp1 expression and its ser 616 phosphorylation were significantly increased in dilated cardiomyopathy (DCM) patients. Male Balb/c mice and H9c2 cardiomyocytes were randomized into three groups: saline, DOX, DOX plus LCZ696. Reduced cardiac function, mitochondrial morphology disturbance, reduced activity of mitochondrial respiration complex I and lowered adenosine triphosphate (ATP) content were detected post DOX stimulation in mice, which could be significantly improved by LCZ696. Fission protein Drp1 and its ser 616 phosphorylation were also increased post DOX and which could be reduced by LCZ696. In vitro, increased cardiomyocyte apoptosis, Drp1 ser 616 phosphorylation post DOX stimulation could be significantly attenuated by LCZ696 or Drp1 specific inhibitor Midivi-1. Furthermore, over-expression of Drp1 abrogated the protection effect of LCZ696 against DOX-induced cardiotoxicity in H9c2 cells. CONCLUSION: The protective effect of LCZ696 against DOX-induced cardiac dysfunction is at least partly associated with alleviating Drp1-mediated mitochondrial dysfunction.

N-Acetylcysteine Prevents Low T3 Syndrome and Attenuates Cardiac Dysfunction in a Male Rat Model of Myocardial Infarction.

Nonthyroidal illness syndrome (NTIS) affects patients with myocardial infarction (MI). Oxidative stress has been implicated as a causative factor of NTIS, and reversed via N-acetylcysteine (NAC). Male Wistar rats submitted to left anterior coronary artery occlusion received NAC or placebo. Decreases in triiodothyronine (T3) levels were noted in MI-placebo at 10 and 28 days post-MI, but not in MI-NAC. Groups exhibited similar infarct areas whereas MI-NAC exhibited higher ejection fraction than did MI-placebo. Left ventricular systolic and diastolic diameters were also preserved in MI-NAC, but not in MI-placebo. Ejection fraction was positively correlated with T3 levels. Oxidative balance was deranged only in MI-placebo animals. Increased type 3 iodothyronine deiodinase expression was detected in the cardiomyocytes of MI-placebo compared with normal heart tissue. NAC was shown to diminish type 3 iodothyronine deiodinase expression and activity in MI-NAC. These results show that restoring redox balance by NAC treatment prevents NTIS- related thyroid hormone derangement and preserves heart function in rats subjected to MI.

Arginine-vasopressin therapy in hypotensive neonates and infants after cardiac surgery: response is unrelated to baseline ventricular function.

We hypothesised that infants with ventricular dysfunction after cardiac surgery have impaired haemodynamic response to arginine-vasopressin therapy. We retrospectively reviewed the medical records of neonates and infants treated with arginine-vasopressin within 48 hours of corrective or palliative cardiac surgery who underwent echocardiographic assessment of ventricular function before initiation of therapy. Patients were classified as "responders" if their systolic blood pressure increased by ⩾10% without increase in catecholamine score or if it was maintained with decreased catecholamine score. Response was assessed 1 hour after maximum upward titration of arginine-vasopressin. A total of 36 children (15 neonates) were reviewed (17 male). The median (interquartile) age was 10.4 weeks (1.1-26.9), and the median weight was 4.3 kg (3.2-5.8). Diagnoses included single ventricle (eight), arch abnormalities (five), atrioventricular septal defect (four), double-outlet right ventricle (three), tetralogy of Fallot (three), and others (13). In all, 12 patients (33%) had ventricular dysfunction. Only 15 (42%) responded favourably according to our definition 1 hour after the "target" arginine-vasopressin dose was achieved. Ventricular dysfunction was not associated with poor response. The overall mortality was 25%, but mortality in patients with ventricular dysfunction was 42%. Favourable response was associated with shorter ICU stay (9.5 days versus 19.5 days, p=0.01). We conclude that arginine-vasopressin fails to increase blood pressure in ~50% of hypotensive children after cardiac surgery. The response rate does not increase with duration of therapy. Ventricular function does not predict haemodynamic response. The mortality in this group is very high. Prospective comparison of vasopressin with other vasoactive agents and/or inotropes is warranted.

Effects of neuregulin GGF2 (cimaglermin alfa) dose and treatment frequency on left ventricular function in rats following myocardial infarction.

Neuregulins are important growth factors involved in cardiac development and response to stress. Certain isoforms and fragments of neuregulin have been found to be cardioprotective. The effects of a full-length neuregulin-1ß isoform, glial growth factor 2 (GGF2; USAN/INN; also called cimaglermin) were investigated in vitro. Various dosing regimens were then evaluated for their effects on left ventricular (LV) function in rats with surgically-induced myocardial infarction. In vitro, GGF2 bound with high affinity to erythroblastic leukemia viral oncogene (ErbB) 4 receptors, potently promoted Akt phosphorylation, as well as reduced cell death following doxorubicin exposure in HL1 cells. Daily GGF2 treatment beginning 7-14 days after left anterior descending coronary artery ligation produced improvements in LV ejection fraction and other measures of LV function and morphology. The improvements in LV function (e.g. 10% point increase in absolute LV ejection fraction) with GGF2 were dose-dependent. LV performance was substantially improved when GGF2 treatment was delivered infrequently, despite a serum half-life of less than 2h and could be maintained for more than 10 months with treatment once weekly or once every 2 weeks. These studies confirm previous findings that GGF2 may improve contractile performance in the failing rat heart and that infrequent exposure to GGF2 may improve LV function and impact remodeling in the failing myocardium. GGF2 is now being developed for the treatment of heart failure in humans.

Impaired Left and Right Ventricular Systolic and Diastolic Function in Response to Exercise in Patients with Diastolic Dysfunction.

BACKGROUND: Diastolic dysfunction (DD) is associated with exercise intolerance. To evaluate mechanisms of exercise intolerance in patients with DD, we performed bicycle stress echocardiography. METHOD AND RESULTS: Doppler measurements were performed at baseline, during exercise and recovery in 26 patients (58 ± 11 years) with DD and normal left ventricular ejection fraction and 6 normal controls (53 ± 5 years). Compared to controls, patients achieved similar target heart rates but lower METs (5.5 ± 2 vs. 9.8 ± 3, P < 0.01) and a higher peak pulmonary artery pressure (PAP) at peak exercise (50 ± 13 vs. 32 ± 7 mmHg, P < 0.01) despite similar PAP at rest and similar mean blood pressure at peak exercise (110.4 ± 18.0 vs. 106.9 ± 11.4 mmHg, P = NS). In patients versus controls, mitral E/E' was similar at baseline (10 ± 3 vs. 8 ± 1.3, P = NS) but higher at recovery (11 ± 2 vs. 7 ± 2, P < 0.05), % mitral filling time was shorter at baseline, onset, and peak exercise, whereas % LV and RV ejection time was similar to controls throughout exercise. Compared to controls, lateral mitral annular S' (11.8 ± 2.5 cm/sec vs. 14.9 ± 1.9 cm/sec, P < 0.02) and tricuspid annular S' (14.8 ± 4.1 cm/sec vs. 19.4 ± 4.0 cm/sec, P < 0.05) were lower at peak exercise in patients. CONCLUSION: Diastolic filling time is reduced at rest and stress while LV ejection time increases normally during exercise in DD. There is a reduced systolic reserve in LV and RV during exercise in DD. These mechanisms contribute to exercise intolerance and elevation of left atrial and PAP in patients with DD.

Hydrogen Sulfide Mitigates Myocardial Infarction via Promotion of Mitochondrial Biogenesis-Dependent M2 Polarization of Macrophages.

AIMS: Macrophages are of key importance for tissue repair after myocardial infarction (MI). Hydrogen sulfide (H2S) has been shown to exert cardioprotective effects in MI. However, the mechanisms by which H2S modulates cardiac remodeling and repair post-MI remain to be clarified. RESULTS: In our current study, we showed that H2S supplementation ameliorated pathological remodeling and dysfunction post-MI in wild-type (WT) and CSE KO mice, resulting in decreased infarct size and mortality, accompanied by an increase in the number of M2-polarized macrophages at the early stage of MI. Strikingly, adoptive transfer of NaHS-treated bone marrow-derived macrophages into WT and CSE KO mice with depleted macrophages also ameliorated MI-induced cardiac functional deterioration. Further mechanistic studies demonstrated that NaHS-induced M2 polarization was achieved by enhanced mitochondrial biogenesis and fatty acid oxidation. INNOVATION AND CONCLUSION: Our study shows (for the first time) that H2S may have the potential as a therapeutic agent for MI via promotion of M2 macrophage polarization. Rebound Track: This work was rejected during standard peer review and rescued by Rebound Peer Review (Antioxid Redox Signal 16:293-296, 2012) with the following serving as open reviewers: Hideo Kimura, Chaoshu Tang, Xiaoli Tian, and Kenneth Olson. Antioxid. Redox Signal. 25, 268-281.

Treatment with anti-RANKL antibody reduces infarct size and attenuates dysfunction impacting on neutrophil-mediated injury.

Selective pharmacological treatments targeting reperfusion injury produced modest protective effects and might be associated with immunosuppression. In order to identify novel and better-tolerated approaches, we focused on the neutralization of receptor activator of nuclear factor kappa-B ligand [RANKL], a cytokine recently shown to activate inflammatory cells (i.e. neutrophils) orchestrating post-infarction injury and repair. Myocardial ischemia (60min) and reperfusion injury was surgically induced in C57Bl/6 mice. In hearts and serum, RANKL was early upregulated during reperfusion. A "one-shot" injection with neutralizing anti-RANKL IgG during ischemia ameliorated myocardial infarct size and function, but not adverse remodeling (determined by Magnetic Resonance Imaging [MRI]) as compared to Vehicle or control IgG. These beneficial effects were accompanied in vivo by reduction in cardiac neutrophil infiltration, reactive oxygen species (ROS) and MMP-9 release. Anti-RANKL IgG treatment suppressed sudden peak of neutrophil granule products in mouse serum early after reperfusion onset. In vitro, RANK mRNA expression was detected in isolated mouse neutrophils. Co-incubation with neutralizing anti-RANKL IgG abrogated RANKL-induced mouse neutrophil degranulation and migration, suggesting a critical role of RANKL in neutrophil-mediated injury. Conversely, anti-RANKL IgG did not affect salvage pathways in cardiac cells (i.e. ERK p42/p44, Akt and STAT-3) or macrophage cardiac infiltration. Finally, treatment with anti-RANKL IgG showed no effect on B and T lymphocyte polarization (in serum, spleen and infarcted myocardium) and circulating chemokines as compared with Vehicle or control IgG. In conclusion, acute treatment with anti-RANKL IgG improved cardiac infarct size and function by potentially impacting on neutrophil-mediated injury and repair.

Influence of metabolic dysfunction on cardiac mechanics in decompensated hypertrophy and heart failure.

Alterations in energetic state of the myocardium are associated with decompensated heart failure in humans and in animal models. However, the functional consequences of the observed changes in energetic state on mechanical function are not known. The primary aim of the study was to quantify mechanical/energetic coupling in the heart and to determine if energetic dysfunction can contribute to mechanical failure. A secondary aim was to apply a quantitative systems pharmacology analysis to investigate the effects of drugs that target cross-bridge cycling kinetics in heart failure-associated energetic dysfunction. Herein, a model of metabolite- and calcium-dependent myocardial mechanics was developed from calcium concentration and tension time courses in rat cardiac muscle obtained at different lengths and stimulation frequencies. The muscle dynamics model accounting for the effect of metabolites was integrated into a model of the cardiac ventricles to simulate pressure-volume dynamics in the heart. This cardiac model was integrated into a simple model of the circulation to investigate the effects of metabolic state on whole-body function. Simulations predict that reductions in metabolite pools observed in canine models of heart failure can cause systolic dysfunction, blood volume expansion, venous congestion, and ventricular dilation. Simulations also predict that myosin-activating drugs may partially counteract the effects of energetic state on cross-bridge mechanics in heart failure while increasing myocardial oxygen consumption. Our model analysis demonstrates how metabolic changes observed in heart failure are alone sufficient to cause systolic dysfunction and whole-body heart failure symptoms.

Cardiac Remodeling: Concepts, Clinical Impact, Pathophysiological Mechanisms and Pharmacologic Treatment / Remodelação Cardíaca: Conceitos, Impacto Clínico, Mecanismos Fisiopatológicos e Tratamento Farmacológico

Abstract Cardiac remodeling is defined as a group of molecular, cellular and interstitial changes that manifest clinically as changes in size, mass, geometry and function of the heart after injury. The process results in poor prognosis because of its association with ventricular dysfunction and malignant arrhythmias. Here, we discuss the concepts and clinical implications of cardiac remodeling, and the pathophysiological role of different factors, including cell death, energy metabolism, oxidative stress, inflammation, collagen, contractile proteins, calcium transport, geometry and neurohormonal activation. Finally, the article describes the pharmacological treatment of cardiac remodeling, which can be divided into three different stages of strategies: consolidated, promising and potential strategies.

Resumo A remodelação cardíaca é definida como um conjunto de mudanças moleculares, celulares e intersticiais cardíacas, que se manifestam clinicamente por alterações no tamanho, massa, geometria e função do coração, em resposta à determinada agressão. Esse processo resulta em mal prognóstico, pois está associado com a progressão da disfunção ventricular e arritmias malignas. Nessa revisão, são discutidos os conceitos e as implicações clínicas da remodelação, além do papel fisiopatológico de diferentes fatores, incluindo morte celular, metabolismo energético, estresse oxidativo, inflamação, colágeno, proteínas contráteis, transporte de cálcio, geometria e ativação neurohormonal. Finalmente, o artigo apresenta o tratamento farmacológico, que pode ser dividido em três estágios: estratégias consolidadas, promissoras e potenciais.