Parallel gene expressions of IL-6 and BNP during cardiac hypertrophy complicated with diastolic dysfunction in spontaneously hypertensive rats

Emerging Therapy for Diabetic Cardiomyopathy: From Molecular Mechanism to Clinical Practice

Diabetic cardiomyopathy is characterized by abnormal myocardial structure or performance in the absence of coronary artery disease or significant valvular heart disease in patients with diabetes mellitus. The spectrum of diabetic cardiomyopathy ranges from subtle myocardial changes to myocardial fibrosis and diastolic function and finally to symptomatic heart failure. Except for sodium–glucose transport protein 2 inhibitors and possibly bariatric and metabolic surgery, there is currently no specific treatment for this distinct disease entity in patients with diabetes. The molecular mechanism of diabetic cardiomyopathy includes impaired nutrient-sensing signaling, dysregulated autophagy, impaired mitochondrial energetics, altered fuel utilization, oxidative stress and lipid peroxidation, advanced glycation end-products, inflammation, impaired calcium homeostasis, abnormal endothelial function and nitric oxide production, aberrant epidermal growth factor receptor signaling, the activation of the renin–angiotensin–aldosterone system and sympathetic hyperactivity, and extracellular matrix accumulation and fibrosis. Here, we summarize several important emerging treatments for diabetic cardiomyopathy targeting specific molecular mechanisms, with evidence from preclinical studies and clinical trials.

Role of some serum biomarkers in the early detection of diabetic cardiomyopathy

AIM

To assess the role of serum biomarkers in early prediction of diabetic cardiomyopathy.

MATERIALS AND METHODS

The participants were three groups of Type 2 diabetes mellitus (DM) patients having diastolic dysfunction (DM-DD), systolic dysfunction (DM-SD) and normal echocardiography (DM-N) with two control groups: non-DM diastolic dysfunction patients (DD) and healthy controls. AGEs, TNF-α, IL-6, IGFBP-7, creatinine and insulin were assessed.

RESULTS

TNF-α, AGEs, creatinine and insulin panel had area under the curve (AUC) of 0.913 in distinguishing DM-DD from DM-N (78.7% sensitivity and 100% specificity). IL-6 and AGEs panel had AUC 0.795 for differentiating DM-SD from DM-DD (90.6% sensitivity). IL-6, TNF-α and AGEs panel had AUC 0.924 for differentiating diabetic cardiomyopathy from DM-N (85% sensitivity and specificity).

CONCLUSION

A panel of AGEs, IL-6, TNF-α, insulin and creatinine might be used for early detection of DM-DD among T2DM patients.

Rhynchophylline ameliorates myocardial ischemia/reperfusion injury through the modulation of mitochondrial mechanisms to mediate myocardial apoptosis

Rhynchophylline (RP), the primary active ingredient of Uncaria rhynchophylla, has an anti-hypertensive effect and protects against ischemia-induced neuronal damage. The present study aimed to examine the roles and mechanisms of RP in myocardial ischemia-reperfusion (MI/R) injury of rat cardiomyocytes. Cell viability, reactive oxygen species, mitochondrial membrane potential (MMP) and cell apoptosis were examined by a Cell Counting Kit-8 assay and flow cytometry, respectively. An ELISA was performed to assess the expression of oxidative stress markers. Spectrophotometry was used to detect the degree of mitochondrial permeability transition pore (mPTP) openness. Western blotting and reverse transcription- quantitative polymerase chain reaction assays were used to evaluate the associated protein and mRNA expression, respectively. The present results demonstrated that RP increased the cell viability of MI/R-induced cardiomyocytes, and suppressed the MI/R-induced apoptosis of cardiomyocytes. Additionally, RP modulated the Ca²⁺ and MMP levels in MI/R-induced cardiomyocytes. Furthermore, RP decreased the oxidative stress and mPTP level of MI/R-induced cardiomyocytes. It was additionally observed that RP affected the apoptosis-associated protein expression and regulated the mitochondrial-associated gene expression in MI/R-induced cardiomyocytes. In conclusion, RP ameliorated MI/R injury through the modulation of mitochondrial mechanisms. The potential effects of RP on the protection of MI/R-induced apoptosis of cardiomyocytes suggest that RP may be an effective target for MI/R therapy.

Cardioprotection of Sheng Mai Yin a classic formula on adriamycin induced myocardial injury in Wistar rats

BACKGROUND

Sheng Mai Yin (SMY), a well-known Chinese herbal medicine, is widely used to treat cardiac diseases characterized by the deficiency of Qi and Yin syndrome in China. SMY-based treatment has been derived from Traditional Chinese Medicine (TCM), officially recorded in the Chinese Pharmacopoeia.

PURPOSE

We aimed to clarify whether SMY attenuates myocardial injury induced by adriamycin in Wistar rats with chronic heart failure (CHF).

METHODS

To quantify ginsenoside Rg1, ophiopogonin D, ophiopogonin D', schisandrin by HPLC. To establish CHF animal model, adriamycin was intraperitoneally injected in Wistar rats for 7 weeks at a dose of 2 mg/kg body weight. Overall, 180 rats were randomly assigned to six groups: control, CHF model, captopril (positive control), high dose (HSMY), medium dose (MSMY), and low dose (LSMY). Experimental rats were fed 0.625 mg/kg captopril and 90 mg/kg, 45 mg/kg, and 22.5 mg/kg SMY, respectively, over 7 weeks. The inflammatory cytokines TNF-α and IL-6 were measured using ELISA. Matrix metalloproteinases (MMPs) were identified using immunohistochemistry (IHC). Both IHC and RT-PCR were used for quantification of COL-IV expression levels in the heart tissues. Scanning electron microscopy (SEM) was used for the visualization of myocardium morphology.

RESULTS

The concentration of ginsenoside Rg1, ophiopogonin D, ophiopogonin D' and schisandrin in SMY was found to be 25.63 ± 3.42 mg, 11.00 ± 1.17 mg, 7.02 ± 0.51 mg, and 25.31 ± 4.28 mg per gram of SMY, respectively. Compared with CHF model group, TNF-α levels were significantly lower (p < .01) in the four drug-administered groups. Moreover, except in the SYM low dose group, IL-6 levels in the other 3 drug-administered groups were also significantly reduced (p < .01). COL-IV expression was also significantly reduced on treatment with high SYM dose (p < .05). IHC results confirmed that SMY and captopril significantly reduced MMPs expression in the heart.

CONCLUSION

SMY could control or slow CHF progression by suppressing pathological changes in the myocardium in CHF models. This could be attributed at least partly to the downregulation of IL-6 and TNF-α and inhibition of overexpression of MMPs and COL-IV, which significantly relieved the cardiac-linked pathologies, decreased the risk of myocardial fibrosis, and inhibited cardiac remodeling. These findings suggested that SMY and captopril have similar efficacy for the treatment of adriamycin-induced myocardial injury. In addition, Chinese herbal preparation SMY may play a role in the treatment of cardiac diseases.

Small heterodimer partner (SHP) contributes to insulin resistance in cardiomyocytes

Small heterodimer partner (SHP) is an atypical nuclear receptor expressed in heart that has been shown to inhibit the hypertrophic response. Here, we assessed the role of SHP in cardiac metabolism and inflammation. Mice fed a high-fat diet (HFD) displayed glucose intolerance accompanied by increased cardiac mRNA levels of Shp. In HL-1 cardiomyocytes, SHP overexpression inhibited both basal and insulin-stimulated glucose uptake and impaired the insulin signalling pathway (evidenced by reduced AKT and AS160 phosphorylation), similar to insulin resistant cells generated by high palmitate/high insulin treatment (HP/HI; 500μM/100nM). In addition, SHP overexpression increased Socs3 mRNA and reduced IRS-1 protein levels. SHP overexpression also induced Cd36 expression (~6.2 fold; p<0.001) linking to the observed intramyocellular lipid accumulation. SHP overexpressing cells further showed altered expression of genes involved in lipid metabolism, i.e., Acaca, Acadvl or Ucp3, augmented NF-κB DNA-binding activity and induced transcripts of inflammatory genes, i.e., Il6 and Tnf mRNA (~4-fold induction, p<0.01). Alterations in metabolism and inflammation found in SHP overexpressing cells were associated with changes in the mRNA levels of Ppara (79% reduction, p<0.001) and Pparg (~58-fold induction, p<0.001). Finally, co-immunoprecipitation studies showed that SHP overexpression strongly reduced the physical interaction between PPARα and the p65 subunit of NF-κB, suggesting that dissociation of these two proteins is one of the mechanisms by which SHP initiates the inflammatory response in cardiac cells. Overall, our results suggest that SHP upregulation upon high-fat feeding leads to lipid accumulation, insulin resistance and inflammation in cardiomyocytes.

Role of Serum Biomarkers in Early Detection of Diabetic Cardiomyopathy in the West Virginian Population

OBJECTIVES

Diabetic cardiomyopathy (DCM) is an established complication of diabetes mellitus. In West Virginia, the especially high incidence of diabetes and heart failure validate the necessity of developing new strategies for earlier detection of DCM. Since most DCM patients remain asymptomatic until the later stages of the disease when the fibrotic complications become irreversible, we aimed to explore biomarkers that can identify early-stage DCM.

METHODS

The patients were grouped into 4 categories based on clinical diabetic and cardiac parameters: Control, Diabetes (DM), Diastolic dysfunction (DD), and Diabetes with diastolic dysfunction (DM+DD), the last group being the preclinical DCM group.

RESULTS

Echocardiography images indicated severe diastolic dysfunction in patients with DD+DM and DD compared to DM or control patients. In the DM and DM+DD groups, TNFα, isoprostane, and leptin were elevated compared to control (p<0.05), as were clinical markers HDL, glucose and hemoglobin A1C. Fibrotic markers IGFBP7 and TGF-β followed the same trend. The Control group showed higher beneficial levels of adiponectin and bilirubin, which were reduced in the DM and DM+DD groups (p<0.05).

CONCLUSION

The results from our study support the clinical application of biomarkers in diagnosing early stage DCM, which will enable attenuation of disease progression prior to the onset of irreversible complications.

Administration of granulocyte-colony stimulating factor accompanied with a balanced diet improves cardiac function alterations induced by high fat diet in mice

Background/Objectives

High fat diet (HFD) is a major contributor to the development of obesity and cardiovascular diseases due to the induction of cardiac structural and hemodynamic abnormalities. We used a model of diabetic cardiomyopathy in C57Bl/6 mice fed with a HFD to investigate the effects of granulocyte-colony stimulating factor (G-CSF), a cytokine known for its beneficial effects in the heart, on cardiac anatomical and functional abnormalities associated with obesity and type 2 diabetes.

Methods

Groups of C57Bl/6 mice were fed with standard diet (n = 8) or HFD (n = 16). After 36 weeks, HFD animals were divided into a group treated with G-CSF + standard diet (n = 8) and a vehicle control group + standard diet (n = 8). Cardiac structure and function were assessed by electrocardiography, echocardiography and treadmill tests, in addition to the evaluation of body weight, fasting glicemia, insulin and glucose tolerance at different time points. Histological analyses were performed in the heart tissue.

Results

HFD consumption induced metabolic alterations characteristic of type 2 diabetes and obesity, as well as cardiac fibrosis and reduced exercise capacity. Upon returning to a standard diet, obese mice body weight returned to non-obese levels. G-CSF administration accelerated the reduction in of body weight in obese mice. Additionally, G-CSF treatment reduced insulin levels, diminished heart fibrosis, increased exercise capacity and reversed cardiac alterations, including bradycardia, elevated QRS amplitude, augmented P amplitude, increased septal wall thickness, left ventricular posterior thickening and cardiac output reduction.

Conclusion

Our results indicate that G-CSF administration caused beneficial effects on obesity-associated cardiac impairment.

Role of inflammation in the pathogenesis of heart failure with preserved ejection fraction and its potential as a therapeutic target

Heart failure (HF) with preserved ejection fraction (HFPEF) is an increasingly prevalent clinical syndrome with many unresolved issues regarding diagnosis, pathophysiology, and treatment. The major pathophysiological mechanisms underlying HFPEF are known to be fibrosis and reduced ventricular compliance, and hypertension (HTN) is perhaps the most significant risk factor for the development of left ventricular diastolic dysfunction (LVDD). Inflammation is one of the earliest events in cardiac stress situations such as pressure and/or volume overload and involves elevated levels of endothelial adhesion molecules as well as increased production and release of inflammatory cytokines and chemokines in the tissue. The latter promotes the infiltration of activated inflammatory cells, particularly monocytes, into the cardiac tissue. Increased monocyte infiltration is seen in the early and late stages of HTN and HFPEF. Once inside the tissue, monocytes differentiate into macrophages and promote cardiac inflammation, tissue injury, and myocardial fibrosis. This review focuses on inflammation as the initial and primary trigger of ventricular remodelling in HTN and LVDD, affecting progression to HFPEF. The link between inflammation and b-type natriuretic peptide (BNP), a clinical marker of cardiac pressure overload which is positively associated with cardiac dysfunction and HF, is also described. Finally, current and prospective therapeutic approaches for HFPEF based on modification of the inflammatory response are reviewed.

Optimisation of reference genes for gene-expression analysis in a rabbit model of left ventricular diastolic dysfunction

Left ventricular diastolic dysfunction (LVDD) is characterized by the disturbance of ventricle’s performance due to its abnormal relaxation or to its increased stiffness during the diastolic phase. The molecular mechanisms underlying LVDD remain unknown. We aimed to identify normalization genes for accurate gene-expression analysis of LVDD using quantitative real-time PCR (RT-PCR) in a new rabbit model of LVDD. Eighteen rabbits were fed with a normal diet (n = 7) or a 0.5% cholesterol-enriched diet supplemented with vitamin D2 (n = 11) for an average of 14.5 weeks. We validated the presence of LVDD in this model using echocardiography for diastolic function assessment. RT-PCR was performed using cDNA derived from left ventricle samples to measure the stability of 10 genes as candidate reference genes (Gapdh, Hprt1, Ppia, Sdha, Rpl5, Actb, Eef1e1, Ywhaz, Pgk1, and G6pd). Using geNorm analysis, we report that Sdha, Gapdh and Hprt1 genes had the highest stability (M <0.2). By contrast, Hprt1 and Rpl5 genes were found to represent the best combination for normalization when using the Normfinder algorithm (stability value of 0.042). Comparison of both normalization strategies highlighted an increase of natriuretic peptides (Bnp and Anp), monocytes chemotactic protein-1 (Mcp-1) and NADPH oxidase subunit (Nox-2) mRNA expressions in ventricle samples of the hypercholesterolemic rabbits compared to controls (P<0.05). This increase correlates with LVDD echocardiographic parameters and most importantly it molecularly validates the presence of the disease in our model. This is the first study emphasizing the selection of stable reference genes for RT-PCR normalization in a rabbit model of LVDD.

Activation of toll-like receptors and inflammasome complexes in the diabetic cardiomyopathy-associated inflammation

Diabetic cardiomyopathy is defined as a ventricular dysfunction initiated by alterations in cardiac energy substrates in the absence of coronary artery disease and hypertension. Hyperglycemia, hyperlipidemia, and insulin resistance are major inducers of the chronic low-grade inflammatory state that characterizes the diabetic heart. Cardiac Toll-like receptors and inflammasome complexes may be key inducers for inflammation probably through NF-κB activation and ROS overproduction. However, metabolic dysregulated factors such as peroxisome proliferator-activated receptors and sirtuins may serve as therapeutic targets to control this response by mitigating both Toll-like receptors and inflammasome signaling.

CD1d-associated expression of NF-kB and cardiac dysfunction in diabetic and obese mice

In patients with obesity and diabetes mellitus, abnormal production of inflammatory factors may result in cardiovascular dysfunction. In the current study, we tested the impact of CD1d-mediated innate immune responses on the expression and activation of NFkB in the hearts of adipose diabetic (db/db) mice. Splenocytes from adult db/db and CD1d-knockout mice of both genders and their wild-type, C57BL/6 and Balb/C counterparts were examined for tumor necrosis factor (TNF)-alpha and TNF-alpha receptor type 1. The percentage of natural killer T (NKT) cells in CD3+ T cells was compared with that in nondiabetic control mice. Despite the absence of inflammatory infiltrates, the hearts of db/db mice showed alterations in TNF-alpha receptor-1 and NFkB activity, including increased expression of both the NFkB p52 and p65 subunits. In the hearts of CD1d-knockout mice, p52 expression was reduced, while p65 expression remained largely unchanged. On echocardiography, the ratio of E to A transmitral flow velocities (an indicator of diastolic function) was significantly decreased in db/db mice after they swam for 30 minutes. These results provide evidence for CD1d-mediated NFkB activation and diastolic dysfunction in the hearts of db/db mice. Therefore, CD1d-associated abnormalities of innate immune responses and TNF-alpha production in splenic tissue may contribute to NFkB activation and cardiac dysfunction in type 2 diabetes.

An overview of the crosstalk between inflammatory processes and metabolic dysregulation during diabetic cardiomyopathy

Metabolic disorders such as obesity, insulin resistance and type 2 diabetes mellitus are all linked to cardiovascular diseases such as cardiac hypertrophy and heart failure. Diabetic cardiomyopathy in particular, is characterized by structural and functional alterations in the heart muscle of people with diabetes that finally lead to heart failure, and which is not directly attributable to coronary artery disease or hypertension. Several mechanisms have been involved in the pathogenesis of diabetic cardiomyopathy, such as alterations in myocardial energy metabolism and calcium signaling. Metabolic disturbances during diabetic cardiomyopathy are characterized by increased lipid oxidation, intramyocardial triglyceride accumulation, and reduced glucose utilization. Overall changes result in enhanced oxidative stress, mitochondrial dysfunction and apoptosis of the cardiomyocytes. On the other hand, the progression of heart failure and cardiac hypertrophy usually entails a local rise in cytokines in cardiac cells and the activation of the proinflammatory transcription factor nuclear factor (NF)-κB. Interestingly, increasing evidences are arising in the recent years that point to a potential link between chronic low-grade inflammation in the heart and metabolic dysregulation. Therefore, in this review we summarize recent new insights into the crosstalk between inflammatory processes and metabolic dysregulation in the failing heart during diabetes, paying special attention to the role of NF-κB and peroxisome proliferator activated receptors (PPARs). In addition, we briefly describe the role of the AMP-activated protein kinase (AMPK), sirtuin 1 (SIRT1) and other pathways regulating cardiac energy metabolism, as well as their relationship with diabetic cardiomyopathy.

Prognostic significance of left ventricular diastolic function in burn patients

Severe inflammation leads to cardiac diastolic dysfunction, an independent prognostic marker for the mortality of critically ill patients. We investigated the possible molecular mechanism from inflammatory cytokines (tumor necrosis factor α [TNF-α] and interleukin 6 [IL-6]) causing left ventricular (LV) diastolic dysfunction in critically burned patients. We consecutively enrolled 56 critically burned patients who were admitted to the intensive care unit and performed transthoracic echocardiography to evaluate LV diastolic function. Sarcoplasmic reticulum Ca²⁺-ATPase 2 (SERCA2) gene expression in HL-1 cardiomyocytes was used as a molecular phenotype of diastolic heart failure. Soluble plasma levels of TNF-α and IL-6 were measured in all subjects. The effect of serum from the burned patients on SERCA2 gene expression of HL-1 cardiomyocytes was investigated. The total body surface area of burned patients was proportional to serum level of IL-6 and TNF-α (P < 0.001 for each). Significant correlations were found for TNF-α and decelerating time, E/A, and E/Em (r² = 0.59, 0.45, and 0.52; P <0.001 for each) and for IL-6 and decelerating time, E/A, and E/Em (r² = 0.63, 0.60, and 0.62; P < 0.001 for each). Diastolic function improved significantly in association with decrease in cytokines after burned patients were transferred to general ward (P < 0.001). Tumor necrosis factor α, IL-6, and sera from critically burned patients downregulated the expression of the SERCA2 gene in HL-1 cardiomyocytes. There was a significant correlation between LV diastolic dysfunction and in-hospital mortality in critically burned patients (hazard ratio, 3.92; P = 0.034) after risk factors were adjusted. Inflammatory cytokines may be associated with cardiac diastolic, which could be an independent prognostic factor in burn patients. Novel therapeutic strategies may be applied in critically burned patients with LV diastolic dysfunction by modulating inflammatory reactions.

Interleukin-10 treatment attenuates pressure overload-induced hypertrophic remodeling and improves heart function via signal transducers and activators of transcription 3-dependent inhibition of nuclear factor-κB

BACKGROUND

Inflammation plays a critical role in adverse cardiac remodeling and heart failure. Therefore, approaches geared toward inhibiting inflammation may provide therapeutic benefits. We tested the hypotheses that genetic deletion of interleukin-10 (IL-10), a potent antiinflammatory cytokine, exacerbates pressure overload-induced adverse cardiac remodeling and hypertrophy and that IL-10 therapy inhibits this pathology.

METHODS AND RESULTS

Cardiac hypertrophy was induced in wild-type and IL-10 knockout mice by isoproterenol (ISO) infusion. ISO-induced left ventricular dysfunction and hypertrophic remodeling, including fibrosis and fetal gene expression, were further exaggerated in knockout mice compared with wild-type mice. Systemic recombinant mouse IL-10 administration markedly improved left ventricular function and not only inhibited but also reversed ISO-induced cardiac remodeling. Intriguingly, a very similar cardioprotective response of IL-10 was found in transverse aortic constriction-induced hypertrophy and heart failure models. In neonatal rat ventricular myocytes and H9c2 myoblasts, ISO activated nuclear factor-κB and inhibited signal transducers and activators of transcription 3 (STAT3) phosphorylation. Interestingly, IL-10 suppressed ISO-induced nuclear factor-κB activation and attenuated STAT3 inhibition. Moreover, pharmacological and genetic inhibition of STAT3 reversed the protective effects of IL-10, whereas ectopic expression of constitutively active STAT3 mimicked the IL-10 responses on the ISO effects, confirming that the IL-10-mediated inhibition of nuclear factor-κB is STAT3 dependent.

CONCLUSION

Taken together, our results suggest IL-10 treatment as a potential therapeutic approach to limit the progression of pressure overload-induced adverse cardiac remodeling.

Plasma levels of tumor necrosis factor-α and interleukin-6 are associated with diastolic heart failure through downregulation of sarcoplasmic reticulum Ca2+ ATPase

OBJECTIVE

The inflammatory process is associated with cardiac diastolic dysfunction, which has been demonstrated to be an independent prognostic marker for the mortality of critically ill patients. We investigated the association among inflammatory cytokines (tumor necrosis factor-α and interleukin-6), diastolic heart failure, and the possible molecular mechanism.

DESIGN

Prospective case-controlled cohort and molecular studies.

SETTING

University hospital and research laboratory.

SUBJECTS

Patients with a diagnosis of diastolic heart failure by echocardiography and matched control subjects from the general population (study group 1) and also subjects from the intensive care unit (study group 2). Sarcoplasmic reticulum Ca2+-ATPase (SERCA2) gene expression and diastolic calcium decay in HL-1 cardiomyocytes were used as molecular phenotypes of diastolic heart failure.

INTERVENTIONS

Soluble plasma levels of tumor necrosis factor-α and interleukin-6 were measured in all subjects. An approximate 1.75-kb promoter of the SERCA2 gene was cloned to the pGL3 luciferase reporter. The effect of tumor necrosis factor-α and interleukin-6 on SERCA2 gene expression and diastolic calcium decay of HL-1 cardiomyocytes were investigated.

MEASUREMENTS AND MAIN RESULTS

Patients with diastolic heart failure had significantly higher plasma levels of tumor necrosis factor-α and interleukin-6 than the control subjects. Significant correlations (p < .01 for each) were found for tumor necrosis factor-α and E/Em (r = .87) and E/A (r = -0.69), and for interleukin-6 and E/Em (r = .80) and E/A (r = -0.65). Cytokine levels were also correlated with diastolic function in critically ill patients (study group 2), and diastolic function improved significantly in association with decrease of cytokines. Tumor necrosis factor-α, interleukin-6, and sera from critically ill patients downregulated the expression of the SERCA2 gene. Tumor necrosis factor-α and interleukin-6 also delayed the diastolic calcium reuptake and decay in cardiomyocytes.

CONCLUSIONS

Through downregulation of SERCA2 gene expression, inflammatory cytokines may cause cardiac diastolic dysfunction by decreasing diastolic calcium reuptake. Our study may suggest novel therapeutic strategies for diastolic heart failure and critically ill patients by modulating inflammatory reactions.

Stromal vascular fraction transplantation as an alternative therapy for ischemic heart failure: anti-inflammatory role

BACKGROUND

The aims of this study were: (1) to show the feasibility of using adipose-derived stromal vascular fraction (SVF) as an alternative to bone marrow mono nuclear cell (BM-MNC) for cell transplantation into chronic ischemic myocardium; and (2) to explore underlying mechanisms with focus on anti-inflammation role of engrafted SVF and BM-MNC post chronic myocardial infarction (MI) against left ventricular (LV) remodelling and cardiac dysfunction.

METHODS

Four weeks after left anterior descending coronary artery ligation, 32 Male Lewis rats with moderate MI were divided into 3 groups. SVF group (n = 12) had SVF cell transplantation (6 × 10(6) cells). BM-MNC group (n = 12) received BM-MNCs (6 × 10(6)) and the control (n = 10) had culture medium. At 4 weeks, after the final echocardiography, histological sections were stained with Styrus red and immunohistochemical staining was performed for α-smooth muscle actin, von Willebrand factor, CD3, CD8 and CD20.

RESULTS

At 4 weeks, in SVF and BM-MNC groups, LV diastolic dimension and LV systolic dimension were smaller and fractional shortening was increased in echocardiography, compared to control group. Histology revealed highest vascular density, CD3+ and CD20+ cells in SVF transplanted group. SVF transplantation decreased myocardial mRNA expression of inflammatory cytokines TNF-α, IL-6, MMP-1, TIMP-1 and inhibited collagen deposition.

CONCLUSIONS

Transplantation of adipose derived SVF cells might be a useful therapeutic option for angiogenesis in chronic ischemic heart disease. Anti-inflammation role for SVF and BM transplantation might partly benefit for the cardioprotective effect for chronic ischemic myocardium.

PPARβ/δ activation blocks lipid-induced inflammatory pathways in mouse heart and human cardiac cells

Owing to its high fat content, the classical Western diet has a range of adverse effects on the heart, including enhanced inflammation, hypertrophy, and contractile dysfunction. Proinflammatory factors secreted by cardiac cells, which are under the transcriptional control of nuclear factor-κB (NF-κB), may contribute to heart failure and dilated cardiomyopathy. The underlying mechanisms are complex, since they are linked to systemic metabolic abnormalities and changes in cardiomyocyte phenotype. Peroxisome proliferator-activated receptors (PPARs) are transcription factors that regulate metabolism and are capable of limiting myocardial inflammation and hypertrophy via inhibition of NF-κB. Since PPARβ/δ is the most prevalent PPAR isoform in the heart, we analyzed the effects of the PPARβ/δ agonist GW501516 on inflammatory parameters. A high-fat diet induced the expression of tumor necrosis factor-α, monocyte chemoattractant protein-1, and interleukin-6, and enhanced the activity of NF-κB in the heart of mice. GW501516 abrogated this enhanced proinflammatory profile. Similar results were obtained when human cardiac AC16 cells exposed to palmitate were coincubated with GW501516. PPARβ/δ activation by GW501516 enhanced the physical interaction between PPARβ/δ and p65, which suggests that this mechanism may also interfere NF-κB transactivation capacity in the heart. GW501516-induced PPARβ/δ activation can attenuate the inflammatory response induced in human cardiac AC16 cells exposed to the saturated fatty acid palmitate and in mice fed a high-fat diet. This is relevant, especially taking into account that PPARβ/δ has been postulated as a potential target in the treatment of obesity and the insulin resistance state.

Attenuation of salt-induced cardiac remodeling and diastolic dysfunction by the GPER agonist G-1 in female mRen2.Lewis rats

INTRODUCTION

The G protein-coupled estrogen receptor (GPER) is expressed in various tissues including the heart. Since the mRen2.Lewis strain exhibits salt-dependent hypertension and early diastolic dysfunction, we assessed the effects of the GPER agonist (G-1, 40 nmol/kg/hr for 14 days) or vehicle (VEH, DMSO/EtOH) on cardiac function and structure.

METHODS

Intact female mRen2.Lewis rats were fed a normal salt (0.5% sodium; NS) diet or a high salt (4% sodium; HS) diet for 10 weeks beginning at 5 weeks of age.

RESULTS

Prolonged intake of HS in mRen2.Lewis females resulted in significantly increased blood pressure, mildly reduced systolic function, and left ventricular (LV) diastolic compliance (as signified by a reduced E deceleration time and E deceleration slope), increased relative wall thickness, myocyte size, and mid-myocardial interstitial and perivascular fibrosis. G-1 administration attenuated wall thickness and myocyte hypertrophy, with nominal effects on blood pressure, LV systolic function, LV compliance and cardiac fibrosis in the HS group. G-1 treatment significantly increased LV lusitropy [early mitral annular descent (e')] independent of prevailing salt, and improved the e'/a' ratio in HS versus NS rats (P<0.05) as determined by tissue Doppler.

CONCLUSION

Activation of GPER improved myocardial relaxation in the hypertensive female mRen2.Lewis rat and reduced cardiac myocyte hypertrophy and wall thickness in those rats fed a high salt diet. Moreover, these advantageous effects of the GPER agonist on ventricular lusitropy and remodeling do not appear to be associated with overt changes in blood pressure.

TNFalpha-antagonist neither improve cardiac remodelling or cardiac function at early stage of heart failure in diabetic rats

OBJECTIVES

Despite tumor necrosis factor alpha (TNFalpha) has been shown to be a prognostic marker in patients with heart failure and previous preclinical study with TNFalpha-antagonist has been demonstrated to improve cardiac function in acute heart failure, recent clinical trials using TNFalpha-antagonist in patients with chronic severe heart failure have been disappointing. The aim was to study why TNFalpha-antagonist may not work during long-term treatment in chronic heart failure (CHF) in experimental model.

METHODS

49 rats were used at the age of 26 weeks: healthy Whistar Kyoto rats (WKY, n = 26) and diabetic (WKY+D, n = 23). Rats in each group received either a 12-week treatment with TNFalpha-antagonist (Etanercept) or NaCl injections.

RESULTS

In diabetic rats, there were increased plasma glucose level and blood pressure. By use of echocardiography diabetic rats displayed not only enlarged and thinned left ventricles but also decreased both systolic and diastolic functions. Moreover, there are increased interleukin-6 (IL6) mRNA levels. However, TNFalpha-antagonist, etanercept, does not improve either cardiac remodelling or cardiac function. IL6 mRNA level remained unchanged after treatment of etanercept.

CONCLUSION

Chronic treatment of TNFalpha-antagonist has no favourable effect on either cardiac remodelling or cardiac function. It is therefore inappropriate to use TNFalpha-antagonist in CHF in diabetes as underlying cause.

Inflammatory pathways in patients with heart failure and preserved ejection fraction

Immune activation is well established in patients with chronic heart failure and reduced ejection fraction (HF and reduced EF) and is associated with an impaired prognosis. Patients with heart failure and preserved ejection fraction (HF and preserved EF) have an impaired prognosis as well. It is not known whether they have signs of immune activation.

METHODS

We studied patients with HF and preserved EF (n=17, NYHA II [n=7]/III [n=10]) and patients with HF and reduced EF (n=17 NYHA II [n=1]/III [n=16]) and 20 controls. Echocardiography demonstrated preserved ejection fraction (LVEF 59+/-9%), but LV hypertrophy in patients with preserved EF as compared with patients with reduced EF (LVEF 23+/-5%). We evaluated levels of TNFalpha, its receptors (sTNFR-1 and 2), IL-6, IL-10 and NT-proBNP.

RESULTS

TNFalpha, was highest in HF with reduced EF (2.87+/-0.65 vs 1.67+/-0.58 pg/mL, p<0.001) compared to preserved EF and similar between HF with preserved EF and controls. However, sTNFR1 (1618+/-384 vs 1017+/-302 pg/mL, p<0.001) and sTNFR2 levels (3554+/-916 vs 2041+/-586 pg/mL, p<0.001) in HF with preserved EF were significantly higher compared with controls. The same was true for IL-6, IL-10 and NT-proBNP. The highest cytokine and NT-proBNP levels were present in HF with reduced EF. There was a negative correlation between TNFalpha, and LVEF (r=- 0.700; p<0.0001) and positive correlations between sTNFR1 and 2 with NT-proBNP.

CONCLUSION

Patients with HF and preserved EF already show signs of systemic-immune activation which may contribute to the impaired prognosis and the progression to HF with reduced EF.

Inhibition of left ventricular remodelling in spontaneously hypertensive rats by G alpha q-protein carboxyl terminus imitation polypeptide GCIP-27 is not entirely dependent on blood pressure

The G(q)-protein is located at the convergent point in the signal transduction pathway that leads to ventricular remodelling. In G-protein signalling pathways, the carboxyl terminus of the G(alpha)-subunit plays a vital role in G-protein-receptor interaction. The aim of the present study was to explore the effects of a synthetic G(alphaq) carboxyl terminus imitation peptide, namely GCIP-27, on left ventricular (LV) remodelling and blood pressure in spontaneous hypertensive rats (SHR). In the present study, 10, 30 or 90 microg/kg, i.p., GCIP-27 was administered for 8 weeks to SHR. In addition, another two groups of SHR were treated with either 6 mg/kg losartan or vehicle (saline). Wistar-Kyoto rats were used as controls. Systolic blood pressure (SBP) was measured using the standard tail-cuff method once every 2 weeks. At the end of the experiment, the LV mass index (LVMI) was evaluated. In addition, LV structure and function, collagen content, microstructure and ultrastructure were examined using echocardiography, the hydroxyproline assay, routine light microscopy and transmission electron microscopy, respectively. In the losartan- and GCIP-27 (10, 30 and 90 microg/kg)-treated groups, SBP was decreased significantly compared with that of the vehicle (saline) group. However, even at the highest concentration used, the hypotensive effect of GCIP-27 was weaker than that of losartan. For example, after 8 weeks treatment, SBP had decreased by 30.4% in the losartan-treated group compared with decreases of 10.5, 13.1 and 18.5% in the 10, 30 and 90 microg/kg GCIP-27-treated groups, respectively. Both GCIP-27 (10, 30 and 90 microg/kg) and losartan (6 mg/kg) significantly reduced LV posterior wall thickness, the thickness of the interventricular septum, collagen content and LVMI, with the effects of GCIP-27 at all three concentrations tested being greater than those of losartan. In conclusion, GCIP-27 effectively attenuates LV remodelling in SHR and the antiremodelling effect may not be dependent entirely on decreases in blood pressure.

Genome-wide association of echocardiographic dimensions, brachial artery endothelial function and treadmill exercise responses in the Framingham Heart Study

BACKGROUND

Echocardiographic left ventricular (LV) measurements, exercise responses to standardized treadmill test (ETT) and brachial artery (BA) vascular function are heritable traits that are associated with cardiovascular disease risk. We conducted a genome-wide association study (GWAS) in the community-based Framingham Heart Study.

METHODS

We estimated multivariable-adjusted residuals for quantitative echocardiography, ETT and BA function traits. Echocardiography residuals were averaged across 4 examinations and included LV mass, diastolic and systolic dimensions, wall thickness, fractional shortening, left atrial and aortic root size. ETT measures (single exam) included systolic blood pressure and heart rate responses during exercise stage 2, and at 3 minutes post-exercise. BA measures (single exam) included vessel diameter, flow-mediated dilation (FMD), and baseline and hyperemic flow responses. Generalized estimating equations (GEE), family-based association tests (FBAT) and variance-components linkage were used to relate multivariable-adjusted trait residuals to 70,987 SNPs (Human 100K GeneChip, Affymetrix) restricted to autosomal SNPs with minor allele frequency > or =0.10, genotype call rate > or =0.80, and Hardy-Weinberg equilibrium p > or = 0.001.

RESULTS

We summarize results from 17 traits in up to 1238 related middle-aged to elderly men and women. Results of all association and linkage analyses are web-posted at http://ncbi.nlm.nih.gov/projects/gap/cgi-bin/study.cgi?id=phs000007 webcite. We confirmed modest-to-strong heritabilities (estimates 0.30-0.52) for several Echo, ETT and BA function traits. Overall, p < 10(-5) in either GEE or FBAT models were observed for 21 SNPs (nine for echocardiography, eleven for ETT and one for BA function). The top SNPs associated were (GEE results): LV diastolic dimension, rs1379659 (SLIT2, p = 1.17*10(-7)); LV systolic dimension, rs10504543 (KCNB2, p = 5.18*10(-6)); LV mass, rs10498091 (p = 5.68*10(-6)); Left atrial size, rs1935881 (FAM5C, p = 6.56*10(-6)); exercise heart rate, rs6847149 (NOLA1, p = 2.74*10(-6)); exercise systolic blood pressure, rs2553268 (WRN, p = 6.3*10(-6)); BA baseline flow, rs3814219 (OBFC1, 9.48*10(-7)), and FMD, rs4148686 (CFTR, p = 1.13*10(-5)). Several SNPs are reasonable biological candidates, with some being related to multiple traits suggesting pleiotropy. The peak LOD score was for LV mass (4.38; chromosome 5); the 1.5 LOD support interval included NRG2.

CONCLUSION

In hypothesis-generating GWAS of echocardiography, ETT and BA vascular function in a moderate-sized community-based sample, we identified several SNPs that are candidates for replication attempts and we provide a web-based GWAS resource for the research community.