Ratio Of Heart Weight Research Articles

Therapeutic Benefit and Gene Network Regulation by Combined Gene Transfer of Apelin, FGF2, and SERCA2a into Ischemic Heart.

Despite considerable advances in cardiovascular disease treatment, heart failure remains a public health challenge. In this context, gene therapy appears as an attractive approach, but clinical trials using single therapeutic molecules result in moderate benefit. With the objective of improving ischemic heart failure therapy, we designed a combined treatment, aimed to simultaneously stimulate angiogenesis, prevent cardiac remodeling, and restore contractile function. We have previously validated IRES-based vectors as powerful tools to co-express genes of interest. Mono- and multicistronic lentivectors expressing fibroblast growth factor 2 (angiogenesis), apelin (cardioprotection), and/or SERCA2a (contractile function) were produced and administrated by intramyocardial injection into a mouse model of myocardial infarction. Data reveal that combined treatment simultaneously improves vessel number, heart function parameters, and fibrosis prevention, due to FGF2, SERCA2a, and apelin, respectively. Furthermore, addition of SERCA2a in the combination decreases cardiomyocyte hypertrophy. Large-scale transcriptome analysis reveals that the triple treatment is the most efficient in restoring angiogenic balance as well as expression of genes involved in cardiac function and remodeling. Our study validates the concept of combined treatment of ischemic heart disease with apelin, FGF2, and SERCA2a and shows that such therapeutic benefit is mediated by a more effective recovery of gene network regulation.

The impact of hydrogen sulfide on the heme oxygenase-1/carbon monoxide system in Coxsackie virus B3-induced myocarditis in mice

Objective: To explore the impact of hydrogen sulfide (H(2)S) on the heme oxygenase-1/carbon monoxide pathway in Coxsackie virus B3 (CVB3)-induced murine myocarditis (VMC) model. Method: A total of 70 inbred male Balb/c mouse (4-6 weeks old) were randomized into the following four groups: Normal, VMC, PAG and NaHS (n=10 for Normal, n=20 for VMC, PAG and NaHS groups). Mice in Normal group were non-infected mice treated with intraperitoneal injection of sterile phosphate-buffered saline daily for 10 days.Mice in VMC group received intraperitoneal CVB3 injection (0.1 ml 10(-5.69)TCID(50)m·ml(-1)·d(-1) and PBS for 10 days), and mice in PAG group received additional intraperitoneal DL-proparglygylcine injection (40 mg·kg(-1)·d(-1) for 10 days), mice in NaHS group received additional intraperitoneal NaHS injection (50 μmol·kg(-1)·d(-1) for 10 days). All mice were sacrificed on day 10th, and body weight and heart weight, the ratio of heart weight to body weight were compared among groups.Pathological changes of heart tissues were observed microscopically by HE and the histopathologic scores were valued.The content of COHb was tested after the gathering of blood specimens while reverse transcription-polymerase chain reaction was used to detect myocardial HO-1 mRNA expression. Results: (1) Pathological findings in myocardium: hearts sections in Normal group were normal and no inflammatory cells and necrosis were found.A notable cellular infiltration, interstitial edema, vascular hyperemia and necrosis were observed in heart section of VMC, PAG and NaHS group.Extensive inflammations and larger area of myocardial cells necrosis were evidenced in PAG group and above changes were significantly reduced in NaHS group.(2) Comparison of the ratio of heart weight to body weight and histological scores of myocardium: the ratio was significantly higher in the VMC, PAG, NaHS groups than in Normal group (P<0.05), which was higher in PAG group and lower in NaHS group as compared with VMC group (both P<0.05). The histopathologic scores of all CVB3 innoculation groups were higher than in the Normal group, which was higher in PAG group and lower in NaHS group as compared to VMC group (both P<0.05). (3) The content of blood COHb in VMC, PAG or NaHS group was significantly higher than that in Normal group (P<0.05), which was significantly lower in PAG group, and higher in NaHS group as compared to VMC group (both P<0.05). (4) The mRNA expression of myocardial HO-1 detected by RT-PCR: weak expression was observed in Normal group, which was significantly upregulated in VMC, PAG and NaHS groups (P<0.05), which was downregulated in PAG group and upregulated in NaHS group as compared to VMC group (both P<0.05). (5) Correlation analysis: blood COHb concentration was positively correlated with myocardial HO-1 mRNA expression(r=0.927, P=0.000), negatively correlated with histopathologic scores(r=-0.753, P=0.000)and the histopathologic scores were negatively correlated with the myocardial HO-1 mRNA expression (r=-0.754, P=0.000). Conclusions: H(2)S could play a protective role in murine CVB3 myocarditis model through inducing HO-1 expression and upregulating HO-1/CO pathway.

Cholecalciterol cholesterol emulsion attenuates experimental autoimmune myocarditis in mice via inhibition of the pyroptosis signaling pathway

1,25-dihydroxyvitamin D3 and its analog (paricalcitol) have beneficial effects on multiple systems and diseases, including myocarditis. However, the therapeutic effect of cholecalciterol cholesterol emulsion (CCE) on myocarditis and the role of pyroptosis in the progress of myocarditis have not been determined. The objective of this study was to investigate the effect of CCE on experimental autoimmune myocarditis and its underlying mechanisms. The ratio of heart weight to body weight was decreased after CCE treatment compared with vehicle-treated controls. In addition, CCE improved the general status of mice, suppressed myocardial apoptosis, and inhibited the pyroptosis signaling pathway. Therefore, CCE can ameliorate experimental autoimmune myocarditis by downregulating the pyroptosis signaling pathway.

Electrophysiological characteristics of pressure overload-induced cardiac hypertrophy and its influence on ventricular arrhythmias.

ObjectiveTo explore the cardiac electrophysiological characteristics of cardiac hypertrophy and its influence on the occurrence of ventricular tachyarrhythmias.MethodsAdult C57BL6 mice were randomly divided into a surgery group and a control group. Thoracic aortic constriction was performed on mice in the surgery group, and cardiac anatomical and ultrasonic evaluations were performed to confirm the success of the cardiac hypertrophy model 4 weeks after the operation. Using the Langendorff method of isolated heart perfusion, monophasic action potentials (MAPs) and the effective refractory period (ERP) at different parts of the heart (including the epi- and endo-myocardium of the left and right ventricles) were measured, and the induction rate of ventricular tachyarrhythmias was observed under programmed electrical stimulus (PES) and burst stimulus. Whole-cell patch-clamp was used to obtain the I-V characteristics of voltage-gated potassium channels in cardiomyocytes of different parts of the heart (including the epi- and endo-myocardium of the left and right ventricles) as well as the channels’ properties of steady-state inactivation and recovery from inactivation.ResultsThe ratio of heart weight to body weight and the ratio of left ventricular weight to body weight in the surgery group were significantly higher than those in the control group (P < 0.05). Ultrasonic evaluation revealed that both interventricular septal diameter (IVSD) and left ventricle posterior wall diameter (LVPWD) in the surgery group were significantly larger than those in the control group (P < 0.05). Under PES and burst stimuli, the induction rates of arrhythmias in the surgery group significantly increased, reaching 41.2% and 23.5%, respectively. Both the QT interval and action potential duration (APD) in the surgery group were significantly longer than in the control group (P<0.01), and the changes showed obvious spatial heterogeneity. Whole-cell patch-clamp recordings demonstrated that the surgery group had significantly lower potassium current densities (IPeak, Ito, IKur, Iss, and IK1) at different parts of the heart than the control group (P < 0.01), and there were significant differences in the half-inactivation voltage (V1/2) and the inactivation-recovery time constant (τ) of Ito and IKur at different parts of the heart (P < 0.01) between the surgery group and the control group. In addition, the surgery group had significantly lower densities of IPeak, Ito, and IKur in cells of the endo-myocardium (P < 0.05), and the changes showed obvious spatial heterogeneity.ConclusionChanges in the current density and function of potassium channels contributed to irregular repolarization in cardiac hypertrophy, and the spatially heterogeneous changes of the channels may increase the occurrence of ventricular arrhythmias that accompany cardiac hypertrophy.

Abstract P472: Prorenin Independently Causes Hypertension And Renal and Cardiac Fibrosis In Cyp1a1-Prorenin Transgenic Rats

Plasma prorenin is commonly elevated in diabetic patients and appears to predict the development of diabetic nephropathy. However, the pathological role of prorenin is unclear. In this study, a transgenic, inducible, hepatic prorenin-overexpressing rat model was generated and the effect of prorenin in organ injury was examined. Four groups of rats (Cyp1a1 prorenin transgenic male and female rats and nontransgenic littermates) were assigned to receive a diet containing 0.3% of the transgene inducer indole-3-carbinol (I3C) for 4 weeks. Plasma prorenin concentration rose from 23±6 to 208±44 (μg/ml) and MAP increased from 77±5 to 138±17 (mmHg), whereas renal prorenin/renin protein expression was unchanged, in transgenic rats fed with I3C diet. The intact prorenin, not renin, in plasma and urine samples was further observed by western blot analysis. Importantly, transgenic rats with high levels of prorenin developed albuminuria, glomerular and tubulointerstitial fibrosis associated with increased expression of TGFß1, PAI-1, collagen and fibronectin. These rats also exhibited cardiac hypertrophy determined by echocardiography, with elevated ratio of heart weight to body weight. Cardiac collagen in interstitial and perivascular area was prominent, accompanied by the increases in mRNA contents of ANP, BNP, ß-MHC, TGFß1 and PAI-1 in the heart tissue. Furthermore, renal protein levels of phosphor-NF-kB-p65 and MCP-1, NAPDH oxidase and MDA, phospho-ß-catenin and phospho-Akt were dramatically increased in prorenin overexpressed rats. These results indicate that prorenin, without being converted to renin, causes arterial hypertension, renal and cardiac fibrosis independently via the induction of inflammation, oxidative stress and the ß-catenin and Akt-mediated signals.

Mitochondrial ALDH2 Deficiency Promotes Fibrosis and Reactive Oxygen Species Formation in the Myocardium of Aged Mice

Enhanced fibrosis and reactive oxygen species (ROS) generation are two major features of aged heart. Since a loss-of-function mutation of ALDH2 was found in nearly half of East Asian population, we explored the impact of ALDH2 deficiency on the process of aging in the heart. We found that the body weight increased profoundly in aged wild-type (WT) mice but not in ALDH2 knockout (KO) mice. However, the ratio of heart weight to body weight increased significantly only in KO mice. Echocardiographic assessment showed that left ventricular ejection fraction of aged WT mice was significantly decreased, which was further aggravated by ALDH2 deficiency. Further study revealed that the compromised cardiac function of aged KO mice might be resulted from PI3K/Akt pathway-mediated fibrosis formation, as shown by remarkable upregulation of collagen I, transforming growth factor-β, and α-smooth muscle actin expression. Aging-induced ROS generation was quantified by the expression of 4-hydroxy-2-nonenal-adducted proteins, which was notably increased in the myocardium of aged KO mice. Besides, the expression of cleaved caspase-3 and 8-oxoguanine DNA glycosylase also increased significantly in the myocardium of aged KO mice. Further study demonstrated that increased ROS generation stimulated a prominent upregulation of ROS scavenger SOD2 expression in the myocardium of aged WT mice but not in KO mice. Our findings suggest that mitochondrial ALDH2 deficiency accelerates aging in the heart by increasing fibrosis formation and oxidative stress.

Role of the calcium sensing receptor in cardiomyocyte apoptosis via mitochondrial dynamics in compensatory hypertrophied myocardium of spontaneously hypertensive rat

Calcium sensing receptor (CaSR) mediates pathological cardiac hypertrophy. Mitochondria maintain their function through fission and fusion and disruption of mitochondrial dynamic is linked to various cardiac diseases. This study examined how inhibition of CaSR by the inhibitor Calhex231 affected the mitochondrial dynamics in a hypertensive model in rats. Spontaneously hypertensive rats (SHRs) and Wistar Kyoto (WKY) rats were used in this study. Cardiac function and blood pressure was evaluated at the end of the study. SHRs showed increases in the ratio of heart weight to body weight and the levels of CaSR; all of these increases were suppressed by Calhex231. Additionally, Calhex231 treatment of SHRs changed the expression of proteins involved in mitochondrial dynamics. Our results demonstrated that CaSR activation induced cardiomyocyte apoptosis through the mitochondrial dynamics mediated apoptotic pathway in hypertensive hearts.

Would healing was improved in mice after myocardial infarction by nature naphthoquinone shikonin

Wound healing has an important impact on ventricular remodeling and functional recovery after myocardial infarction (MI). Nature naphthoquinone shikonin has been shown to promote wound healing by reducing reactive oxygen species and inflammation. However, it is still unknown whether shikonin can increase wound healing in infarcted hearts. C57BL6 mice were subjected to MI surgery. Infarcted mice were treated with shikonin by oral gavage, 25 mg/kg once a day for four weeks, or the equal volume of vehicle as controls. At the end of the experiments, echocardiography was performed. Echo study showed that shikonin improved left ventricular fractional shortening and ejection fraction, and that it decreased left ventricular dilation and increased infarcted wall thickening. Moreover, the ratio of heart weight to body weight was decreased in shikonin‐treated group, compared with vehicle group. Masson's trichrome staining demonstrated fibrosis was inhibited in non‐infarcted regions in shikonin‐treated group. Taken together, shikonin promoted wound healing and improved left ventricular functional recovery in infarcted hearts.

Zinc deficiency worsens and zinc supplement prevents the development of diabetic cardiomyopathy, respectively, in the db/db mice: A key role of Nrf2

Diabetic cardiomyopathy (DCM) is highly prevalent in the type 2 diabetic (T2DM) patients. Zinc is one of the important essential trace metals, and its deficiency associates with various chronic pathogenesis, including vascular diseases. We used B6.BKS(D)‐Leprdb/J (db/db) mice as a T2DM mouse models and provided mice, for six months, with normal diet containing three levels of zinc: deficient, adequate, and supplemented, to explore the role of zinc in the development or progression of DCM. Cardiac function, reflected by the EF%, was significantly decreased along with increases in left ventricle mass and the ratio of heart weight to tibial length, in the db/db mice. As molecular cardiac hypertrophy marker, ANP protein was also significantly increased in db/db mice. The cardiac dysfunction and hypertrophy were also accompanied with significant increases in fibrotic responses (accumulated collagens and increased TGF‐β and CTGF expression) and inflammatory responses and signalings (increased expression of TNF‐α, IL‐1β, CARD9, and BCL10 and activated p38 MAPK) in the heart of db/db mice. All these diabetic effects were exacerbated and ameliorated by zinc deficiency and zinc supplement, respectively. Mechanistically the oxidative stress and damage, mirrored by 3‐NT and 4‐HNE, was significantly increased along with significant decrease in the expression of Nrf2 and its down‐stream antioxidants (NQO‐1 and catalase), which was exacerbated and ameliorated by zinc deficiency and zinc supplement, respectively, in the heart of the db/db mice. These results suggest that zinc deficiency worsens the pathological progression of cardiac disorders in type 2 diabetic db/db mice, which can be significantly prevented by zinc supplement, all which may be related to the role of Nrf2 in the prevention of DCM development and progression.Support or Funding InformationThis work was supported in part by the Scholarship of China Scholarship Council(No.201506175180)

KLF15 protects against isoproterenol-induced cardiac hypertrophy via regulation of cell death and inhibition of Akt/mTOR signaling

Increasing evidence indicate that the Krüppel-like factor KLF15, a member of Cys2/His2 zinc-finger DNA-binding proteins, attenuates cardiac hypertrophy. However, the role of KLF15 in cardiovascular system is largely unknown and the exact molecular mechanism of its protective function is not fully elucidated. In the present study, we established a mouse model of cardiac hypertrophy and found that KLF15 expression was down-regulated in hypertrophic hearts. To evaluate the roles of KLF15 in cardiac hypertrophy, we generated transgenic mice overexpressing KLF15 of KLF15 knockdown mice and subsequently induced cardiac hypertrophy. The results indicated that KLF15 overexpression protects mice from ISO-induced cardiac hypertrophy, with reduced ratios of heart weight (HW)/body weight (BW) and cross-sectional area. We also observed that KLF15 overexpression attenuated cardiac fibrosis, inhibited apoptosis and induced autophagy in cardiomyocytes compared with KLF15 knockdown mice. More importantly, we found that the KLF15 overexpression inhibited the Akt/mTOR signaling pathway. Taken together, our findings imply that KLF15 possesses potential anti-hypertrophic and anti-fibrotic functions, possibly via regulation of cell death pathways and the inhibition of Akt/mTOR axis. KLF15 may constitute an efficient candidate drug for the treatment of heart failure and other cardiovascular diseases.

Antihypertensive and Antihypertrophic Effects of Acupuncture at PC6 Acupoints in Spontaneously Hypertensive Rats and the Underlying Mechanisms.

The aim of this work is to investigate the effect of electroacupuncture (EA) at PC6 on the hypertension and myocardial hypertrophy in spontaneously hypertensive rats (SHRs). Thirty SHRs were randomized into model, SHR + EA, and SHR + Sham EA group with WKY rats as normal control. EA was applied once a day in 8 consecutive weeks. The blood pressure (BP), cardiac function, and hypertrophy as well as the underlying mechanisms were investigated. After EA treatment, the enhanced BP in SHR + EA group was significantly lower compared to both the period before EA and model group. Echocardiographic, morphological studies showed that the enhanced left ventricular anterior and posterior wall end-diastolic (LVAWd and LVPWd) thickness, diameters and cross-sectional area (CSA) of cardiac myocyte, as well as the ratio of heart weight to body weight (HW/BW), were markedly diminished in SHR + EA group, while the reduced left ventricular ejection fraction, left ventricular short axis fraction shortening, and E/A ratio were significantly ameliorated. The levels of Angiotensin-converting enzyme (ACE) and Angiotensin II Type 1 and 2 receptors (AT1R, AT2R) in SHRs were also significantly attenuated by EA. The results suggest that EA at bilateral PC6 could arrest the hypertension development and ameliorate the cardiac hypertrophy and malfunction in SHRs, which might be mediated by the regulation of ACE, AT1R, and AT2R.

Taiwanese and Japanese yam (Dioscorea spp.) extracts attenuate doxorubicin-induced cardiotoxicity in mice

The present study was designed to explore whether yam could protect the heart from doxorubicin (DOX)-induced oxidative stress leading to cardiotoxicity in vivo. In this study, the protective effects of water and ethanol extracts of three varieties of yam, including water extracts of Dioscorea japonica Thunb., ethanol extracts of D. japonica Thunb., water extracts of Dioscorea alata, ethanol extracts of D. alata, water extracts of Dioscorea purpurea, and ethanol extracts of D. purpurea, against DOX-induced cardiotoxicity in experimental mice were evaluated. DOX treatment led to significant decreases in the ratio of heart weight to body weight and heart rate, and increases in blood pressure and the serum level of lactate dehydrogenase, a marker of cardiotoxicity, were recovered by yam extracts, especially in water extracts of D. alata. Yam extracts also decreased the cardiac levels of thiobarbituric acid relative substances, reactive oxygen species, and inflammatory factors, as well as the expression of nuclear factor kappa B, while ethanol extracts of D. japonica Thunb. and D. purpurea were shown to be more potent. Moreover, yam extracts had a role in increasing the activities of glutathione peroxidase and superoxide dismutase, thus improving the DOX-induced alterations in oxidative status in the heart tissue of DOX-treated mice. All ethanol extracts of yam exhibited their antiapoptotic abilities on caspase-3 activation and mitochondrial dysfunction, and ethanol extracts of D. alata still exerted a superior effect. Based on these findings, it can be concluded that yam has significant cardioprotective properties against DOX-induced damage via its multiple effects on antioxidant, anti-inflammatory, or antiapoptotic activities.

Forensic postmortem computed tomography: volumetric measurement of the heart and liver.

The purpose of this study was to investigate the utility of postmortem computed tomography (PMCT) images in estimating organ sizes and to examine the use of the cardiothoracic ratio (CTR). We included 45 individuals (19 females), who underwent a medico-legal autopsy. Using the computer software program Mimics®, we determined in situ heart and liver volumes derived from linear measurements (width, height and depth) on a whole body PMCT-scan, and compared the volumes with ex vivo volumes derived by CT-scan of the eviscerated heart and liver. The ex vivo volumes were also compared with the organ weights. Further, we compared the CTR with the ex vivo heart volume and a heart weight-ratio (HWR). Intra- and inter-observer analyses were performed. We found no correlation between the in situ and ex vivo volumes of the heart and liver. However, a highly significant correlation was found between the ex vivo volumes and weights of the heart and liver. No correlations between CTR and the ex vivo heart volume nor with HWR was found. Concerning cardiomegaly, we found no agreement between the CTR and HWR. The intra- and inter-observer analyses showed no significant differences. Noninvasive in situ PMCT methods for organ measuring, as performed in this study, are not useful tools in forensic pathology. The best method to estimate organ volume is a CT-scan of the eviscerated organ. PMCT-determined CTR seems to be useless for ascertaining cardiomegaly, as it neither correlated with the ex vivo heart volume nor with the HWR.

Morphometric Documentation of a High Prevalence of Left Ventricular Dilated Cardiomyopathy in Both Clinically Normal and Cyanotic Mature Commercial Broiler Breeder Roosters with Comparisons to Market-Age Broilers.

Previous studies documented the common occurrence of transitory cyanosis and echocardiographic aortic insufficiency in mature commercial broiler breeder roosters. During further investigations, we observed a high prevalence of hearts exhibiting extensive dilation of the left ventricle chamber compatible with dilated left ventricular cardiomyopathy present in both cyanotic and normal subpopulations. We conducted quantitative studies focused on documentation of cardiac ventricle parameters by using simple gross morphometric methods performed on formalin-fixed hearts obtained from both clinically normal roosters and those exhibiting variable transitory cyanosis, echocardiographic aortic insufficiency, or both. A high prevalence of often dramatic left ventricular dilation reflected in enlarged left ventricular chamber areas and elevated left ventricle-to-total ventricle area ratios was morphometrically documented. However, no statistically significant differences in the occurrence of ventricular abnormalities were observed between normal and cyanotic roosters. Age-associated changes were also demonstrated by comparative morphometric studies on hearts from normal market-age broilers (average age of 7 wk) and those of mature roosters (average age of 42 wk). Elevation in both left and right ventricular weight-to-total heart weight ratios dramatically increased with aging. In addition, values (average ± SD) for the left ventricle chamber area-to-total ventricle area ratios increased from 3.2 ± 2.0% in broilers up to 10.0 ± 8.8% in roosters. None of the normal broilers studied demonstrated left ventricular volume ratios above 10%, whereas 33% of the roosters had left ventricular volume ratios above 10%, including 13% with ratios of 20% or higher. However, the left ventricle wall area-to-body weight ratios were much closer for the two age groups (0.85 ± 0.18 cm(2)/kg in broilers and 0.79 ± 0.13 cm(2)/kg in roosters). Also, the standard right ventricle-to-total ventricle weight ratio (RV/TV) went from 0.18 ± 0.04 in broilers to 0.25 ± 0.12 in roosters, whereas the left ventricle-to-total ventricle weight ratios were similar for the two age groups (0.74 ± 0.12 and 0.75 ± 0.08 in broilers and roosters, respectively). Our results for RV/TV in normal broilers were similar to the reported values for normal market-age broilers. In contrast, 36% of the roosters had RV/TV above values reported for broilers considered reflective of right ventricular hypertrophy due to pulmonary hypertension, whereas 4% had values above the reported threshold for broilers dying with ascites (ratios greater than 0.0249 and 0.299, respectively). However, ascites was not observed for any of the roosters. Although essentially all cardiac morphometric parameters demonstrated statistically significant correlations with the age-class group comparisons, significance could not be documented for comparisons between cardiomorphometrics and the subjective occurrences of transitory cyanosis or echocardiographic aortic insufficiency.

Mitogen-Activated Protein Kinase and Intracellular Polyamine Signaling Is Involved in TRPV1 Activation-Induced Cardiac Hypertrophy.

BackgroundThe transient receptor potential vanilloid type 1 (TRPV1) is expressed in the cardiovascular system, and increased TRPV1 expression has been associated with cardiac hypertrophy. Nevertheless, the role of TRPV1 in the pathogenesis of cardiac hypertrophy and the underlying molecular mechanisms remain unclear.Methods and ResultsIn cultured cardiomyocytes, activation of TRPV1 increased cell size and elevated expression of atrial natriuretic peptide mRNA and intracellular calcium level, which was reversed by TRPV1 antagonist capsazepine. Increased expression of phosphorylated calmodulin‐dependent protein kinase IIδ and mitogen‐activated protein kinases were found in TRPV1 agonist capsaicin‐treated cardiomyocytes. Selective inhibitor of calmodulin‐dependent protein kinase IIδ decreased phosphorylation of extracellular signal–regulated kinases and p38. Capsaicin induced an increase in expression of ornithine decarboxylase protein, which is the key enzyme in polyamine biosynthesis in cardiomyocytes. Nevertheless, there was no obvious change of ornithine decarboxylase expression in TRPV1 knockdown cells after capsaicin treatment, and specific inhibitors of calmodulin‐dependent protein kinase IIδ or p38 downregulated the capsaicin‐induced expression of ornithine decarboxylase. Capsazepine alleviated the increase in cross‐sectional area of cardiomyocytes and the ratio of heart weight to body weight and improved cardiac function, including left ventricular internal end‐diastolic and ‐systolic dimensions and ejection fraction and fractional shortening percentages, in mice treated with transverse aorta constriction. Capsazepine also reduced expression of ornithine decarboxylase and cardiac polyamine levels. Transverse aorta constriction induced increases in phosphorylated calmodulin‐dependent protein kinase IIδ and extracellular signal–regulated kinases, and p38 and Serca2a were attenuated by capsazepine treatment.ConclusionsThis study revealed that the mitogen‐activated protein kinase signaling pathway and intracellular polyamines are essential for TRPV1 activation–induced cardiac hypertrophy.

Abstract 63: Reduction in Glucocorticoid Receptor Expression Attenuates Pressure Overload-induced Cardiac Hypertrophy and Promotes Heart Failure in Mice

Background: Left ventricular hypertrophy (LVH) is an independent risk factor for heart failure and sudden death. In addition, LVH is also a compensatory mechanism that helps the heart cope with pressure overload. Stress is considered one factor that is related to cardiac outcomes. Glucocorticoids are primary stress hormones, whose role in the heart is poorly understood. Here, we hypothesize that a reduction in the expression of the glucocorticoid receptor (GR) would decrease cardiac hypertrophy in response to pressure overload. Methods and Results: The GR homozygous mutation (GR-/-) is embryonic lethal. However, GR heterozygous mice (GR+/-) show a normal phenotype. We subjected GR+/- mice to transverse aortic constriction (TAC). At four weeks after TAC, the ratio of heart weight to tibia length increased significantly in wild-type mice (control) littermates compared with GR+/- mice. Cardiac myocyte size was also smaller in GR+/- mice vs controls, suggesting an attenuated cardiac growth response in these mice. In addition, GR+/- hearts displayed increased cell death and enhanced fibrosis in response to TAC. Cardiac function, determined by EF% and FS% (measured using the Vevo2100 imaging system), was significantly reduced in GR+/- mice compared with controls at eight weeks post-operation, while LVEDD was increased. Together, with the increased ratio of lung weight to body weight in GR+/- mice at eight weeks following TAC, this suggests an exaggerated heart failure in GR+/- mice. In vitro, hydrocortisone-induced cell growth in H9c2 cells was abolished by GR knockdown using siRNA. Finally, we looked at the mechanisms by which GR may play a role in the development of hypertrophy. We found reduced ERK-JNK activity in GR+/- hearts, suggesting that the reduced hypertrophic response in GR+/- mice occurs, at least partially, through abolished JNK and ERK activity. Conclusion: The glucocorticoid receptor is required for cardiac hypertrophy and protects the heart from heart failure during cardiac pressure overload.

The Effect of Diazepam on the Function of Hypertrophied Rats’ Hearts in Ischemia-Reperfusion Conditions

: Background: Hypertrophied hearts are susceptible to ischemic injury. Besides, cardiac vulnerability could be changed in the presence of diazepam. Objectives: The current study aimed to investigate the effect of diazepam on hypertrophied rats’ hearts in ischemia-reperfusion conditions. Materials and Methods: Male Wistar rats (body weight 210 - 270 gr) were administered with isoproterenol (4 mg/kg body weight, intraperitoneally for 7 days) alone or along with diazepam (1 and 5 mg/kg body weight, intraperitoneally for 5 days). The control rats received normal saline intraperitoneally. The animal s’ hearts were isolated according to langendorff setup and were passed through baseline, ischemia, and reperfusion stages. Then, cardiac mass index (ratio of heart weight to body weight) was measured. Cardiac functional parameters, including left ventricular developed pressure and rate pressure product, were also assessed at baseline and following ischemia. The data were analyzed using ANOVA and P < 0.05 was considered to be statistically significant. Results: Isoproterenol-induced cardiac hypertrophy was significantly reduced by both doses of diazepam compared to the group only treated with isoproterenol (P < 0.05) although it did not reach the control level. However, diazepam administration (1 and 5 mg/kg) did not change isoproterenol-induced exacerbated ischemia-reperfusion injury compared to the control group (P = 0.001 and P = 0.013, respectively). Conclusions: Diazepam relatively prevented the isoproterenol–induced cardiac hypertrophy in the animal model. This effect could be probably explained by the modification of oxidative stress and preservation of intracellular calcium concentration. Considering the common clinical usage of diazepam, as a peripheral benzodiazepine ligand, antihypertrophic effects of diazepam are recommended to be investigated in clinical trials.

LCZ696, an angiotensin receptor-neprilysin inhibitor, improves cardiac function with the attenuation of fibrosis in heart failure with reduced ejection fraction in streptozotocin-induced diabetic mice.

Angiotensin receptor-neprilysin inhibitors (ARNis) acts an ARB and neprilysin inhibitor. Diabetes mellitus significantly increases the risk of cardiovascular disease and heart failure (HF). Therefore, we evaluated the effects and mechanisms of ARNi in HF with reduced ejection fraction (HFrEF) in streptozotocin-induced diabetic mice. Male C57BL/6J mice were injected with streptozotocin to produce diabetic mice. After myocardial reperfusion injury, diabetic mice were randomized to treatment for 4 weeks with LCZ696 (60 mg/kg), valsartan (30 mg/kg), or no treatment (n = 26-28 in each group). Cardiac function was assessed by a pressure-volume Millar catheter. The ratios of heart weight to body weight in the valsartan (P = 0.02) and LCZ696 (P = 0.005) groups were significantly less than that in the control group. Treatment with LCZ696 improved LVEF (43 ± 3.4%) with a significantly reduction of atrial natriuretic peptide mRNA in the left ventricle compared with that in the control group (29 ± 3.2%) (P = 0.006). The fibrotic area in the LCZ696 group was significantly suppressed compared with those in the control (P = 0.003) and valsartan (P = 0.04) groups. Moreover, the mRNA level of transforming growth factor-β (TGF-β) in the left ventricle was suppressed in the LCZ696 group compared with that in the control (P = 0.002) group. The ARNi LCZ696 improved cardiac function with the reduction of fibrosis in an HF-rEF model in diabetic mice, by suppressing TGF-β. This effect may be due to the specific inhibition of neprilysin, beyond the ARB effect of LCZ696.

Intermedin1-53 Protects Against Myocardial Fibrosis by Inhibiting Endoplasmic Reticulum Stress and Inflammation Induced by Homocysteine in Apolipoprotein E-Deficient Mice.

Aim: Endoplasmic reticulum stress (ERS) and inflammation participate in cardiac fibrosis. Importantly, a novel paracrine/autocrine peptide intermedin1–53 (IMD1–53) in the heart inhibits myocardial fibrosis in rats. However, the mechanisms are yet to be fully elucidated.Methods: Myocardial fibrosis in apolipoprotein E-deficient (ApoE -/-) mice and neonatal rat cardiac fibroblasts (CFs) were induced using homocysteine (Hcy).Results: IMD1–53 inhibited myocardial fibrosis in vivo and in vitro. Picrosirius red staining showed that IMD1–53 reduced myocardial interstitial collagen deposition in ApoE-/- mice treated with Hcy and decreased the expression of myocardial collagen I and III, which was further verified in rat CFs. IMD1–53 attenuated myocardial hypertrophy, as shown by cardiomyocyte cross-sectional area, ratio of heart weight to body weight, and mRNA levels of atrial natriuretic peptide and brain natriuretic peptide. IMD1–53 inhibited the upregulation of ERS hallmarkers such as glucose-regulated protein 78 (GRP78), GRP94, activating transcription factor 6 (ATF6), ATF4, inositol-requiring enzyme 1α, spliced-X-box-binding protein-1, protein kinase receptor-like ER kinase, and eukaryotic translation initiation factor 2α in mouse myocardium and rat CFs treated with Hcy. In addition, IMD1–53 decreased the production of inflammatory factors such as tumor necrosis factor-α, monocyte chemotactic protein-1, interleukin-6 (IL-6), and IL-1β in the mouse myocardium and rat CFs treated with Hcy. Concurrently, IMD1–53 ameliorated the expression of nuclear factor-κB, transforming growth factor-β1, and c-Jun N-terminal kinase in the mouse myocardium and rat CFs treated with Hcy.Conclusions: IMD potentially protects against myocardial fibrosis induced by Hcy in ApoE-/- mice, possibly via attenuating myocardial ERS and inflammation.

CHARACTERISTICS OF WATER-SOLUBLE AND LIPOSOMAL QUERCETINE ON THE WEIGHT MEASURING VALUES, CARDIAC INTERVALOGRAM PARAMETERS AND TOLERANCE TO PHYSICAL LOAD OF ANIMALS IN TYPE 2 DIABETES MELLITUS WITH CONCOMITANT OBESITY

The model of type 2 diabetes mellitus with concomitant obesity (single injection of streptozotocine, 30 mg/kg, after four-week keeping on high-fat diet) provided a basis for the study of water-soluble and liposomal quercetine efficacy (10 mg/kg, introduction starting 10 weeks after streptozotocine injection and lasting 14 days). Body weight and heart weight changes as well as the correlation of the values (heart weight ratio) were investigated. The exercise tolerance was determined through swimming test and cardiac intervalography was registered. Body weight as well as heart weight and heart weight ratio were found to grow in the animals with type 2 diabetes mellitus and concomitant obesity, whereas the exercise tolerance was found to decrease. Cardiac intervalogram findings revealed disbalanced parasympathetic and sympathetic influence on the heart and insufficient centralization of cardiac rhythm control. Drug injection was found to contribute to the improvement of weight measuring values, exercise tolerance and keeping the balance of cardiac intervalography values. The liposomal quercetine form was found to possess higher efficacy, as compared with the water-soluble one.