Cardiac Dysfunction In Mice Research Articles

Intracerebral Hemorrhage Induces Cardiac Dysfunction in Mice Without Primary Cardiac Disease.

Background: Intracerebral hemorrhage (ICH) is a life threatening stroke subtype and a worldwide health problem. In this study, we investigate brain-heart interaction after ICH in mice and test whether ICH induces cardiac dysfunction in the absence of primary cardiac disease. We also investigate underlying mechanisms such as oxidative stress and inflammatory responses in mediating cardiac dysfunction post-ICH in mice.Methods: Male, adult (3–4 m) C57BL/6J mice were subjected to sham surgery or ICH using an autologous blood injection model (n = 16/group). Cardiac function was evaluated at 7 and 28 days after ICH using echocardiography (n = 8/group per time point). Western blot and immunostaining analysis were employed to assess oxidative stress and inflammatory responses in the heart.Results: Mice subjected to ICH exhibited significantly decreased cardiac contractile function measured by left ventricular ejection fraction (LVEF) and left ventricular fractional shortening (LVFS) at 7 and 28 days after ICH compared to sham-control mice (p < 0.05). ICH induced cardiac dysfunction was significantly worse at 28 days than at 7 days after ICH (p < 0.05). ICH in mice significantly increased cardiomyocyte apoptosis, inflammatory factor expression and inflammatory cell infiltration in heart tissue, and induced cardiac oxidative stress at 7 days post-ICH compared to sham-control mice. Compared to sham-control mice, ICH-mice also exhibited significantly increased (p < 0.05) cardiomyocyte hypertrophy and cardiac fibrosis at 28 days after ICH.Conclusions: ICH induces significant and progressive cardiac dysfunction in mice. ICH increases cardiac oxidative stress and inflammatory factor expression in heart tissue which may play key roles in ICH-induced cardiac dysfunction.

BMI1 promotes cardiac fibrosis in ischemia-induced heart failure via the PTEN-PI3K/Akt-mTOR signaling pathway.

Cardiac fibrosis has been known to play an important role in the etiology of heart failure after myocardial infarction (MI). B lymphoma Mo-MLV insertion region 1 homolog (BMI1), a transcriptional repressor, is important for fibrogenesis in the kidneys. However, the effect of BMI1 on ischemia-induced cardiac fibrosis remains unclear. BMI1 was strongly expressed in the infarct region 1 wk post-MI in mice and was detected by Western blot and histological analyses. Lentivirus-mediated overexpression of BMI1 significantly promoted cardiac fibrosis, worsened cardiac function 4 wk after the intervention in vivo, and enhanced the proliferation and migration capabilities of fibroblasts in vitro , whereas downregulation of BMI1 decreased cardiac fibrosis and prevented cardiac dysfunction in mice 4 wk post-MI in vivo. Furthermore, upregulated BMI1 inhibited phosphatase and tensin homolog (PTEN) expression, enhanced phosphatidylinositol 3-kinase (PI3K) expression, and increased the phosphorylation level of Akt and mammalian target of rapamycin (mTOR) in mice 4 wk after lentiviral infection, which was in accordance with the changes seen in their infarcted myocardial tissues. At the same time, the effects of BMI1 on cardiac fibroblasts were reversed in vitro when these cells were exposed to NVP-BEZ235, a dual-kinase (PI3K/mTOR) inhibitor. In conclusion, BMI1 is associated with cardiac fibrosis and dysfunction after MI by regulating cardiac fibroblast proliferation and migration, and these effects could be partially explained by the regulation of the PTEN-PI3K/Akt-mTOR pathway. NEW & NOTEWORTHY Ischemia-induced B lymphoma Mo-MLV insertion region 1 homolog (BMI1) significantly promoted cardiac fibrosis and worsened cardiac function in vivo, whereas downregulation of BMI1 decreased cardiac fibrosis and prevented cardiac dysfunction in myocardial infarcted mice. BMI1 also enhanced proliferation and migration capabilities of fibroblasts in vitro; these effects were reversed by NVP-BEZ235. Effects of BMI1 on cardiac fibrosis could be partially explained by regulation of the phosphatase and tensin homolog-phosphatidylinositol 3-kinase/Akt-mammalian target of rapamycin pathway.

Augmentation of NAD+ levels by enzymatic action of NAD(P)H quinone oxidoreductase 1 attenuates adriamycin-induced cardiac dysfunction in mice

BackgroundAdriamycin (ADR) is a powerful chemotherapeutic agent extensively used to treat various human neoplasms. However, its clinical utility is hampered due to severe adverse side effects i.e. cardiotoxicity and heart failure. ADR-induced cardiomyopathy (AIC) has been reported to be caused by myocardial damage and dysfunction through oxidative stress, DNA damage, and inflammatory responses. Nonetheless, the remedies for AIC are even not established. Therefore, we illustrate the role of NAD+/NADH modulation by NAD(P)H quinone oxidoreductase 1 (NQO1) enzymatic action on AIC. Methods and resultsAIC was established by intraperitoneal injection of ADR in C57BL/6 wild-type (WT) and NQO1 knockout (NQO1−/−) mice. All Mice were orally administered dunnione (named NQO1 substrate) before and after exposure to ADR. Cardiac biomarker levels in the plasma, cardiac dysfunction, oxidative biomarkers, and mRNA and protein levels of pro-inflammatory mediators were determined compared the cardiac toxicity of each experimental group. All biomarkers of Cardiac damage and oxidative stress, and mRNA levels of pro-inflammatory cytokines including cardiac dysfunction were increased in ADR-treated both WT and NQO1−/− mice. However, this increase was significantly reduced by dunnione in WT, but not in NQO1−/− mice. In addition, a decrease in SIRT1 activity due to a reduction in the NAD+/NADH ratio by PARP-1 hyperactivation was associated with AIC through increased nuclear factor (NF)-κB p65 and p53 acetylation in both WT and NQO1−/− mice. While an elevation in NAD+/NADH ratio via NQO1 enzymatic action using dunnione recovered SIRT1 activity and subsequently deacetylated NF-κB p65 and p53, however not in NQO1−/− mice, thereby attenuating AIC. ConclusionThus, modulation of NAD+/NADH by NQO1 may be a novel therapeutic approach to prevent chemotherapy-associated heart failure, including AIC.

GW29-e0396 Polydatin Ameliorates Cardiac Dysfunction in mice with myocardial infarction injury via upregulation of Sirt3

GW29-e0396 Polydatin Ameliorates Cardiac Dysfunction in mice with myocardial infarction injury via upregulation of Sirt3

Trimetazidine Attenuates Cardiac Dysfunction in Endotoxemia and Sepsis by Promoting Neutrophil Migration.

Aims: Cardiac dysfunction can be a fatal complication during severe sepsis. The migration of neutrophils is significantly impaired during severe sepsis. We sought to determine the role of trimetazidine (TMZ) in regulation of neutrophil migration to the heart in a mouse model of sepsis and endotoxemia, and to identify the mechanism whereby TMZ confers a survival advantage.Methods and Results: C57/BL6 mice were (1) injected with LPS followed by 24-h TMZ administration, or (2) treated with TMZ (20 mg/kg/day) for 1 week post cecal ligation and puncture (CLP) operation. Echocardiography and Millar system detection showed that TMZ alleviated cardiac dysfunction and histological staining showed the failure of neutrophils migration to heart in both LPS- and CLP-induced mice. Bone marrow transplantation revealed that TMZ-pretreated bone marrow cells improved LPS- and CLP-induced myocardial dysfunction and enhanced neutrophil recruitment in heart. In CXCL2-mediated chemotaxis assays, TMZ increased neutrophils migration via AMPK/Nrf2-dependent up-regulation of CXCR2 and inhibition of GRK2. Furthermore, using luciferase reporter gene and chromatin immunoprecipitation assays, we found that TMZ promoted the binding of the Nrf2 and CXCR2 promoter regions directly. Application of CXCR2 inhibitor completely reversed the protective effects of TMZ in vivo. Co-culture of neutrophils and cardiomyocytes further validated that TMZ decreased LPS-induced cardiomyocyte pyroptosis by targeting neutrophils.Conclusion: Our findings suggested TMZ as a potential therapeutic agent for septic or endotoxemia associated cardiac dysfunction in mice.STUDY HIGHLIGHTS What is the current knowledge on the topic?Migration of neutrophils is significantly impaired during severe sepsis, but the underlying mechanisms remain unknown.What question did this study address?The effects of TMZ on cardiac dysfunction via neutrophils migration.What this study adds to our knowledgeTMZ attenuated LPS-induced cardiomyocyte pyroptosis and cardiac dysfunction by promoting neutrophils recruitment to the heart tissues via CXCR2.How this might change clinical pharmacology or translational scienceOur findings suggested TMZ as a potential therapeutic agent for septic cardiac dysfunction.

Toll-like receptor 2 deficiency hyperactivates the FoxO1 transcription factor and induces aging-associated cardiac dysfunction in mice

Toll-like receptors (TLRs) are a family of pattern-recognition receptors involved in innate immunity. Previous studies have shown that TLR2 inhibition protects the heart from acute stress, including myocardial infarction and doxorubicin-induced cardiotoxicity in animal models. However, the role of TLR2 in the development of aging-associated heart failure is not known. In this work, we studied aging-associated changes in structure and function of TLR2-deficient mice hearts. Whereas young TLR2-KO mice did not develop marked cardiac dysfunction, 8- and 12-month-old TLR2-KO mice exhibited spontaneous adverse cardiac remodeling and cardiac dysfunction in an age-dependent manner. The hearts of the 8-month-old TLR2-KO mice had increased fibrosis, cell death, and reactivation of fetal genes. Moreover, TLR2-KO hearts displayed reduced infiltration by macrophages, increased numbers of myofibroblasts and atrophic cardiomyocytes, and higher levels of the atrophy-related ubiquitin ligases MuRF-1 and atrogin-1. Mechanistically, TLR2 deficiency impaired the PI3K/Akt signaling pathway, leading to hyperactivation of the transcription factor Forkhead box protein O1 (FoxO1) and, in turn, to elevated expression of FoxO target genes involved in the regulation of muscle wasting and cell death. AS1842856-mediated chemical inhibition of FoxO1 reduced the expression of the atrophy-related ubiquitin ligases and significantly reversed the adverse cardiac remodeling while improving the contractile functions in the TLR2-KO mice. Interestingly, TLR2 levels decreased in hearts of older mice, and the activation of TLR1/2 signaling improved cardiac functions in these mice. These findings suggest that TLR2 signaling is essential for protecting the heart against aging-associated adverse remodeling and contractile dysfunction in mice.

Exercise Training Has Contrasting Effects in Myocardial Infarction and Pressure Overload Due to Divergent Endothelial Nitric Oxide Synthase Regulation.

The beneficial effects of exercise training (EX) on cardiac pathology are well recognized. Previously, we found that the effects of EX on cardiac dysfunction in mice critically depend on the underlying etiology. EX exerted beneficial effects after myocardial infarction (MI); however, cardiac pathology following pressure overload produced by transverse aortic constriction (TAC) was aggravated by EX. In the presented study, we investigated whether the contrasting effects of EX on cardiac dysfunction can be explained by an etiology-specific response of endothelial nitric oxide (NO) synthase (eNOS) to EX, which divergently affects the balance between nitric oxide and superoxide. For this purpose, mice were exposed to eight weeks of voluntary wheel running or sedentary housing (SED), immediately after sham, MI, or TAC surgery. Left ventricular (LV) function was assessed using echocardiography and hemodynamic measurements. EX ameliorated LV dysfunction and remodeling after MI, but not following TAC, in which EX even aggravated fibrosis. Strikingly, EX attenuated superoxide levels after MI, but exacerbated NOS-dependent superoxide levels following TAC. Similarly, elevated eNOS S-glutathionylation and eNOS monomerization, which were observed in both MI and TAC, were corrected by EX in MI, but aggravated by EX after TAC. Additionally, EX reduced antioxidant activity in TAC, while it was maintained following EX in MI. In conclusion, the present study shows that EX mitigates cardiac dysfunction after MI, likely by attenuating eNOS uncoupling-mediated oxidative stress, whereas EX tends to aggravate cardiac dysfunction following TAC, likely due to exacerbating eNOS-mediated oxidative stress.

PO-251 Modulation of NAD+levels by NQO1 enzymatic action alleviates adriamycin-induced cardiac dysfunction in mice

IntroductionAdriamycin (ADR) is a potent anticancer drug widely used to treat a variety of human neoplasms. Nevertheless, its clinical application is hampered because of severe side effects such as cardiotoxicity and heart failure. ADR-induced cardiomyopathy (AIC) has been reported to be caused by myocardial damage and dysfunction through oxidative stress, DNA damage, and inflammatory responses. But, the remedy for ADR cardiomyopathy is still not developed. We describe the effect of NAD+/NADH modulation by NAD(P)H quinone oxidoreductase 1 (NQO1) enzymatic action on AIC.Material and methodsAIC was established by three times intraperitoneal injections of ADR (cumulative dose of 12 mg/kg i.p.; 4 mg/kg every day for 3 consecutive days) in C57BL/6 wild-type (WT) and NQO1 knockout (NQO1-/-) mice. Before and after exposure to ADR, the mice were orally administered dunnione (20 mg/kg), a substrate of NQO1. Cardiac biomarker levels in the plasma, cardiac dysfunction, oxidative biomarkers, and mRNA and protein levels of pro-inflammatory mediators were determined to compare the cardiac toxicity of each experimental group.Results and discussionsAll biomarkers of Cardiac damage and oxidative stress, and mRNA levels of pro-inflammatory cytokines, including cardiac dysfunction were significantly increased in ADR-treated both WT and NQO1-/- mice. However, this increase was significantly reduced by dunnione in WT, but not in NQO1-/- mice. In addition, a decrease in SIRT1 activity due to a decrease in the NAD+/NADH ratio by PARP-1 hyperactivation was associated with ADR-induced cardiotoxicity through increased nuclear factor (NF)-κB p65 and p53 acetylation in both WT and NQO1-/- mice, whereas an increase in NAD+/NADH ratio by NQO1 enzymatic action using dunnione as a substrate recovered SIRT1 activity and subsequently deacetylated NF-κB p65 and p53 in WT, however not in NQO1-/- mice thereby attenuating AIC.ConclusionDunnione has a cardioprotective effect against ADR-induced cardiomyopathy through NQO1 enzymatic action. Thus, modulation of NAD+/NADH by NQO1 may be a novel therapeutic approach to prevent chemotherapy-associated heart failure, including AIC.

MiR-146b protect against sepsis induced mice myocardial injury through inhibition of Notch1

Myocardial dysfunction is a major cause of death in sepsis. MicroRNA-146b (miR-146b) has been reported to be related to myocardial disease. However, the role of miR-146b in sepsis as well as myocardial injury is still unclear. Septic cardiac dysfunction in mice was induced by cecal ligation and puncture (CLP) and miR-146b was found increased significantly in the myocardium tissue of CLP mice. It was found that up-regulation of miR-146b by agomiR injection suppressed expression of IL-1β in mice as well as myocardium apoptosis in CLP mice. However, suppression of miR-146b by antagomiR injection had inverse effects. Notch1 was identified as a target gene of miR-146b by bioinformatics analysis. And it was verified that in cardiomyocytes, the decrease of miR146b led to increase of both the mRNA and protein level of Notch1 and vice versa. In septic mice serum stimulated cardiomyocytes, up-regulation of miR-146b decreased the level of Notch1 and Hes1. The knockout of Notch1 in transgenic mice showed that the deficiency of Notch1 improved myocardial injury induced by CLP operation. The apoptosis of cardiomyocytes was relieved and the expression of IL-1β was decreased. In conclusion, miR-146b targets to Notch1 and protected cardiomyocytes against inflammation and apoptosis.

Inhibition of NF-κB Pathway with IKK-16 or Linagliptin Attenuates the Cardiac Dysfunction Associated with Polymicrobial Sepsis in Mice with Preexisting Type 2 Diabetes Mellitus (T2DM)

Introduction: Patients with diabetes are more susceptible to infections and sepsis. Activation of nuclear factor-κB (NF-κB) plays a substantial role in the pathophysiology of sepsis and diabetes. Here we investigate i) the effect of preexisting type 2 diabetes mellitus on cardiac dysfunction associated with sepsis and ii) whether inhibition of NF-κB using IKK-16 or linagliptin attenuates cardiac dysfunction in mice with sepsis and diabetes. Methods: Ten-week old male C57BL/6 mice received high fat (HFD) or chow diet for 12 weeks, and were then subjected to caecal ligation and puncture (CLP) or sham surgery for 24 hours. At 1 hour after CLP, mice received IKK-16, linagliptin, or vehicle. Results: Administration of HFD resulted in a significant impairment in glucose tolerance and a small, but significant, reduction in ejection fraction. Immunoblot analysis of hearts tissue showed that HFD caused significant NF-κB pathway activation and expression of inducible nitric oxide synthase (iNOS). Mice on HFD subjected to CLP showed further (i) decline in EF, (ii) increase in NF-κB pathway activation, (iii) increase in iNOS expression, (iv) an increase in serum ALT, and (v) a significant renal dysfunction. Treatment of HFD-CLP mice with IKK-16 or linagliptin resulted in significant reduction of the CLP-induced i) cardiac dysfunction, ii) NF-κB pathway activation, and iii) iNOS expression when compared to mice treated with vehicle. Conclusion: Our results show that HFD results in inflammation and cardiac dysfunction. Moreover, a preexisting diabetic phenotype worsened the cardiac dysfunction associated with CLP-sepsis. Most notably, inhibition of NF-κB reduced the cardiac dysfunction caused by sepsis in animals with preexisting T2DM. Disclosure S. Al Zoubi: None. J. Chen: None. L. Martin: None. C. Murphy: None. G.S. Purvis: None. F. Chiazza: Other Relationship; Self; Boehringer Ingelheim GmbH. D. Collotta: None. M. Collino: None. C. Thiemermann: None.

Echocardiographic Strain Analysis for the Early Detection of Left Ventricular Systolic/Diastolic Dysfunction and Dyssynchrony in a Mouse Model of Physiological Aging.

Heart disease is the leading cause of hospitalization and death worldwide, severely affecting health care costs. Aging is a significant risk factor for heart disease, and the senescent heart is characterized by structural and functional changes including diastolic and systolic dysfunction as well as left ventricular (LV) dyssynchrony. Speckle tracking–based strain echocardiography (STE) has been shown as a noninvasive, reproducible, and highly sensitive methodology to evaluate LV function in both animal models and humans. Herein, we describe the efficiency of this technique as a comprehensive and sensitive method for the detection of age-related cardiac dysfunction in mice. Compared with conventional echocardiographic measurements, radial and longitudinal strain, and reverse longitudinal strain were able to detect subtle changes in systolic and diastolic cardiac function in mice at an earlier time point during aging. Additionally, the data show a gradual and consistent decrease with age in regional contractility throughout the entire LV, in both radial and longitudinal axes. Furthermore, we observed that LV segmental dyssynchrony in longitudinal axis reliably differentiated between aged and young mice. Therefore, we propose the use of echocardiographic strain as a highly sensitive and accurate technology enabling and evaluating the effect of new treatments to fight age-induced cardiac disease.

Role of dendritic cells in lipopolysaccharide induced cardiac dysfunction in mice

To observe the role of dendritic cells (DC) in lipopolysaccharide (LPS)-induced myocardial dysfunction in mice. Eighty wild type male C57BL/6 mice were divided into four groups, according to random number table method: sham group, DC inhibitors in control group (VAG539-sham group), LPS sepsis model group (LPS group) and DC inhibitors pretreatment group (VAG539-LPS group), 20 in each group. The cardiac dysfunction model of sepsis mice was established by LPS intraperitoneal injection; the sham group was injected with the same dose of normal saline. VAG539-sham group and VAG539-LPS group were injected with the DC inhibitor VAG539 (30 mg/kg, twice per day, for 2 days) before injection with normal saline or LPS, respectively. Ten mice in each group were used to observe the 14-day survival rate. Mean arterial pressure (MAP) of the remaining 10 mice was measured through the small animal tail artery cannula; the cardiac function [including the heart rate (HR), left ventricular ejection fraction (LVEF) and short axial shortening rate (FS)] were evaluated by small animal echocardiography; the aggregation and maturation of myocardial DC were detected by flow cytometry; and serum inflammatory factors [including tumor necrosis factor-α (TNF-α), interleukins (IL-12, IL-6)] were detected by enzyme linked immunosorbent assay (ELISA). Compared with sham group, the 14-day cumulative survival rate in LPS group was significantly reduced, while HR, MAP, LVEF and FS were significantly decreased, and the number of DC in myocardial tissues was significantly increased, and the levels of serum inflammatory factors were increased significantly. The 14-day cumulative survival rate in VAG539-LPS group was significantly higher than that in the LPS group (55% vs. 15%, P < 0.05). Compared with LPS group, after pretreatment by VAG539, the HR, MAP, LVEF and FS were significantly increased [HR (bpm): 610±25 vs. 556±28, MAP (mmHg, 1 mmHg = 0.133 kPa): 68±6 vs. 42±2, LVEF: 0.48±0.02 vs. 0.30±0.03, FS: (34±3)% vs. (14±2)%, P < 0.05]; the number of DC in myocardial tissue was significantly decreased from 6.5% to 3.7%; the level of serum inflammatory factors were significantly decreased [TNF-α (ng/L): 192.00±25.45 vs. 291.34±23.12, IL-12 (ng/L): 58.44±12.37 vs. 78.43±11.24, IL-6 (ng/L): 46.97±8.12 vs. 149.12±15.45, all P < 0.05]. Sepsis can cause cardiac dysfunction, and it can play an important role by inhibiting the DC cell function of myocardium and reducing the expression of inflammatory factors.

The Orphan Receptor GPR35 Contributes to Angiotensin II-Induced Hypertension and Cardiac Dysfunction in Mice.

BACKGROUNDThe orphan receptor G protein–coupled receptor 35 (GPR35) has been associated with a range of diseases, including cancer, inflammatory bowel disease, diabetes, hypertension, and heart failure. To assess the potential for GPR35 as a therapeutic target in cardiovascular disease, this study investigated the cardiovascular phenotype of a GPR35 knockout mouse under both basal conditions and following pathophysiological stimulation.METHODSBlood pressure was monitored in male wild-type and GPR35 knockout mice over 7–14 days using implantable telemetry. Cardiac function and dimensions were assessed using echocardiography, and cardiomyocyte morphology evaluated histologically. Two weeks of angiotensin II (Ang II) infusion was used to investigate the effects of GPR35 deficiency under pathophysiological conditions. Gpr35 messenger RNA expression in cardiovascular tissues was assessed using quantitative polymerase chain reaction.RESULTSThere were no significant differences in blood pressure, cardiac function, or cardiomyocyte morphology in GPR35 knockout mice compared with wild-type mice. Following Ang II infusion, GPR35 knockout mice were protected from significant increases in systolic, diastolic, and mean arterial blood pressure or impaired left ventricular systolic function, in contrast to wild-type mice. There were no significant differences in Gpr35 messenger RNA expression in heart, kidney, and aorta following Ang II infusion in wild-type mice.CONCLUSIONSAlthough GPR35 does not appear to influence basal cardiovascular regulation, these findings demonstrate that it plays an important pathological role in the development of Ang II–induced hypertension and impaired cardiac function. This suggests that GPR35 is a potential novel drug target for therapeutic intervention in hypertension.

Catecholamine-Induced Senescence of Endothelial Cells and Bone Marrow Cells Promotes Cardiac Dysfunction in Mice.

Previous studies have suggested that cellular senescence plays a central role in the progression of pathologic changes in the failing heart. It is well known that the sympathetic nervous system is activated in patients with heart failure, and this change is associated with poor clinical outcomes. Sympathetic activation increases the levels of various catecholamines, such as epinephrine and norepinephrine, but the contribution of these catecholamines to cellular senescence associated with heart failure remains to be determined. We found that catecholamine infusion induced senescence of endothelial cells and bone marrow cells, and promoted cardiac dysfunction in mice. In C57BL/6NCr mice, the continuous infusion of isoproterenol-induced cardiac inflammation and cardiac dysfunction. Expression of p53, a master regulator of cellular senescence, was increased in the cardiac tissue and bone marrow cells of these mice. Suppression of cellular senescence by genetic deletion of p53 in endothelial cells or bone marrow cells led to improvement of isoproterenol-induced cardiac dysfunction. In vitro studies showed that adrenergic signaling increased the expression of p53 and adhesion molecules by endothelial cells and macrophages. Our results indicate that catecholamine-induced senescence of endothelial cells and bone marrow cells plays a pivotal role in the progression of heart failure. Suppression of catecholamine-p53 signaling is crucial for inhibition of remodeling in the failing heart.

Macrophage migration inhibitory factor knockout attenuates endotoxin-induced cardiac dysfunction in mice.

Accumulated evidence suggests that macrophage migration inhibitory factor (MIF) plays a key role not only in acute and chronic inflammatory diseases but also in cardiovascular disease. The cardiac dysfunction is related to lipopolysac-charide (LPS) in sepsis. This study was designed to examine whether MIF mediates LPS-induced cardiac dysfunction and address the mechanisms. Echocardiography, immunohistochemical analysis, cell shortening/re-lengthening, and intracellular Ca2+ fluores-cence evaluation were performed in whole hearts and isolated cardiomyocytes from C57 and MIF knockout mice treated with or without LPS. Reactive oxygen species and protein carbonyl formation were measured. Activation of mitogen-activated protein kinases and endoplasmic reticulum stress markers were evaluated using Western blot analysis. Human umbilical vein endothelial cells (HUVECs) were transfected with lentiviruses carrying short hairpin RNA (shRNA) to inhibit MIF. Echocardiography revealed that cardiac function was impaired and macrophage infiltration was increased in LPS-treated C57 mice. Peak shortening and maximal velocity of shortening/re-lengthening were significantly reduced and the duration of re-lengthening was prolonged in LPS-treated C57 mice. Reactive oxygen species and protein carbonyl levels were increased in LPS-treated C57 mice. These dysfunctional changes were attenuated in MIF knockout mice that were challenged with LPS. Western blot analysis revealed that activated p-JNK, p-ERK, and endoplasmic reticulum stress protein marker expression was decreased in LPS-treated MIF knockout mice. p-ERK and p-JNK levels were knocked down in MIF shRNA-transfected HUVECs. The data collectively suggest that MIF mediates LPS-induced cardiac dysfunction in murine cardiomyocytes, which was attenuated by MIF knockout, and the therapeutic option with regard to MIF may aid the management of cardiac dysfunction in sepsis.

Amphiregulin enhances cardiac fibrosis and aggravates cardiac dysfunction in mice with experimental myocardial infarction partly through activating EGFR-dependent pathway.

Cardiac fibrosis (CF), a main process of ventricular remodeling after myocardial infarction (MI), plays a crucial role in the pathogenesis of heart failure (HF) post-MI. It is known that amphiregulin (AR) is involved in fibrosis of several organs. However, the expression of AR and its role post-MI are yet to be determined. This study aimed to investigate the impact of AR on CF post-MI and related mechanisms. Significantly upregulated AR expression was evidenced in the infarct border zone of MI mice in vivo and the AR secretion was enhanced in macrophages, but not in cardiac fibroblasts. In vitro, treatment with AR increased cardiac fibroblast migration, proliferation and collagen synthesis, and upregulated the expression of epidermal growth factor receptor (EGFR) and the downstream genes such as Akt, ERK1/2 and Samd2/3 on cardiac fibroblasts. All these effects could be abrogated by pretreatment with a specific EGFR inhibitor. To verify the functions of AR in MI hearts, lentivirus-AR-shRNA and negative control vectors were delivered into the infarct border zone. After 28days, knock-down of AR increased the survival rate and improved cardiac function, while decreasing the extent of myocardial fibrosis of MI mice. Moreover, EGFR and the downstream genes were significantly downregulated in lentivirus-AR-shRNA treated MI mice. Our results thus indicate that AR plays an important role in promoting CF after MI partly though activating the EGFR pathway. Targeting AR might be a novel therapeutic option for attenuating CF and improve cardiac function after MI.

Gallic acid attenuates pulmonary fibrosis in a mouse model of transverse aortic contraction-induced heart failure

Gallic acid, a trihydroxybenzoic acid found in tea and other plants, attenuates cardiac hypertrophy, fibrosis, and hypertension in animal models. However, the role of gallic acid in heart failure remains unknown. In this study, we show that gallic acid administration prevents heart failure-induced pulmonary fibrosis. Heart failure induced in mice, 8weeks after transverse aortic constriction (TAC) surgery, was confirmed by echocardiography. Treatment for 2weeks with gallic acid but not furosemide prevented cardiac dysfunction in mice. Gallic acid significantly inhibited TAC-induced pathological changes in the lungs, such as increased lung mass, pulmonary fibrosis, and damaged alveolar morphology. It also decreased the expression of fibrosis-related genes, including collagen types I and III, fibronectin, connective tissue growth factor (CTGF), and phosphorylated Smad3. Further, it inhibited the expression of epithelial-mesenchymal transition (EMT)-related genes, such as N-cadherin, vimentin, E-cadherin, SNAI1, and TWIST1. We suggest that gallic acid has therapeutic potential for the treatment of heart failure-induced pulmonary fibrosis.

Robust suppression of cardiac energy catabolism with marked accumulation of energy substrates during lipopolysaccharide-induced cardiac dysfunction in mice

BackgroundMyocardial contractile dysfunction in sepsis has been attributed mainly to increased inflammatory cytokines, insulin resistance, and impaired oxidative phosphorylation of fatty acids (FAs). However, precise molecular mechanisms underlying the cardiac dysfunction in sepsis remain to be determined. We previously reported major shift in myocardial energy substrates from FAs to glucose, and increased hepatic ketogenesis in mice lacking fatty acid-binding protein 4 (FABP4) and FABP5 (DKO). PurposeWe sought to determine whether a shift of energy substrates from FAs to glucose and increased availability of ketone bodies are beneficial or detrimental to cardiac function under the septic condition. MethodsLipopolysaccharide (LPS, 10mg/kg) was intraperitoneally injected into wild-type (WT) and DKO mice. Twelve hours after injection, cardiac function was assessed by echocardiography and serum and hearts were collected for further analyses. ResultsCardiac contractile function was more deteriorated by LPS injection in DKO mice than WT mice despite comparable changes in pro-inflammatory cytokine production. LPS injection reduced myocardial uptake of FA tracer by 30% in both types of mice, while uptake of the glucose tracer did not significantly change in either group of mice in sepsis. Storage of glycogen and triacylglycerol in hearts was remarkably increased by LPS injection in both mice. Metabolome analysis revealed that LPS-induced suppression of pool size in the TCA cycle was more enhanced in DKO hearts. A tracing study with 13C6-glucose further revealed that LPS injection substantially reduced glucose-derived metabolites in the TCA cycle and related amino acids in DKO hearts. Consistent with these findings, glucose oxidation in vitro was similarly and markedly reduced in both mice. Serum concentration of β-hydroxybutyrate and cardiac expression of genes associated with ketolysis were reduced in septic mice. ConclusionsOur study demonstrated that LPS-induced cardiac contractile dysfunction is associated with the robust suppression of catabolism of energy substrates including FAs, glucose and ketone bodies and accumulation of glycogen and triacylglycerol in the heart. Thus, a fuel shift from FAs to glucose and/or ketone bodies may be detrimental rather than protective under septic conditions.

PM2.5 exposure in utero contributes to neonatal cardiac dysfunction in mice

ObjectiveExposure of fine particulate matter (PM2.5) to pregnant dams has been shown to be strongly associated with adverse cardiovascular outcomes in offspring at adulthood, however, effects evident during neonatal periods are unclear. We designed this study to examine cardiac function of neonatal mice (14 days old) exposed to in utero PM2.5. MethodsPregnant FVB female mice were exposed either to filtered air (FA) or PM2.5 at an average concentration of 91.78 μg/m3 for 6 h/day, 5 days/wk (similar to exposure in a large industrial area) throughout the gestation period (21 days). After birth, animals were analyzed at day 14 of life. ResultsFourteen day old mice exposed to PM2.5 during the in utero period demonstrated decreased fractional shortening (%FS, 41.1 ± 1.2% FA, 33.7 ± 1.2% PM2.5, p < 0.01) and LVEDd (2.87 ± 0.08 mm FA, 2.58 ± 0.07 mm PM2.5, p < 0.05) compared to FA exposed mice. Contractile kinetics and calcium transients in isolated cardiomyocytes from PM2.5 exposed mice illustrated reduced peak shortening (%PS, 16.7 ± 0.5% FA, 14.7 ± 0.4% PM2.5, p < 0.01), negative contractile velocity (-dL/dT, −6.91 ± 0.3 μm/s FA, −5.46 ± 0.2 μm/s PM2.5, p < 0.001), increased time to relaxation 90% (TR90, 0.07 ± 0.003 s FA, 0.08 ± 0.004 s PM2.5, p < 0.05), decreased calcium transient amplitude (Δ340/380, 33.8 ± 3.4 FA, 29.5 ± 2.8 p.m.2.5) and slower fluorescence decay rate (τ, 0.72 ± 0.1 s FA, 1.16 ± 0.15 s PM2.5, p < 0.05). Immunoblotting studies demonstrated alterations in expression of Ca2+ handling proteins- SERCA-2A, p-PLN, NCX and CaV1.2 in hearts of 14 day old in utero PM2.5 exposed mice compared to FA exposed hearts. ConclusionPM2.5 exposure during the critical in utero period adversely affects the developing mouse fetus leading to functional cardiac changes that were evident during the very early (14 days) stages of adolescence. These data demonstrated that exposure to PM2.5 during the gestation period significantly impacts cardiovascular outcomes early in life.

160 Cardiac dysfunction in mice with reduced striatin expression

PurposeSome protein kinases are regulated in STRIPAK complexes, with striatin (STRN) forming a scaffold. STRN mutations are associated with hypertension in humans and decreased expression of STRN causes arrhythmias and...