Potential novel pharmacological therapies for myocardial remodelling

Platelet-Rich Plasma for Heart Cell Regeneration Post-myocardial Infarction: A Propitious Therapeutic Approach

Globally, one of the primary factors leading to death is cardiovascular disorders, specifically coronary artery disease, which leads to myocardial infarction (MI). This article investigates the potential of platelet-rich plasma (PRP) therapy for regenerating cardiac cells following MI. We look into the pathophysiology of MI, current treatment methods, and the heart's limited ability to heal itself. This is done to see if PRP could help the heart heal faster, reduce the size of the infarct, and stop scar tissue from forming. We analyze the production procedure of PRP, its composition of growth factors, and its utilization in many medical domains. The ways that PRP helps the heart heal are also being looked into. This includes how it affects inflammation, oxidative stress, angiogenesis, and cell proliferation. Although we recognize the existing constraints, we meticulously take into account issues such as standardization, therapeutic variance, and potential harmful effects. This study highlights the importance of comprehensive guidelines, continuous research, and enhanced clinical applications to fully harness the potential of platelet-rich plasma in the regeneration of cardiac cells after a heart attack.

Cardiac Reverse Remodeling in Ischemic Heart Disease with Novel Therapies for Heart Failure with Reduced Ejection Fraction

Despite the improvements in the treatment of coronary artery disease (CAD) and acute myocardial infarction (MI) over the past 20 years, ischemic heart disease (IHD) continues to be the most common cause of heart failure (HF). In clinical trials, over 70% of patients diagnosed with HF had IHD as the underlying cause. Furthermore, IHD predicts a worse outcome for patients with HF, leading to a substantial increase in late morbidity, mortality, and healthcare costs. In recent years, new pharmacological therapies have emerged for the treatment of HF, such as sodium-glucose cotransporter-2 inhibitors, angiotensin receptor-neprilysin inhibitors, selective cardiac myosin activators, and oral soluble guanylate cyclase stimulators, demonstrating clear or potential benefits in patients with HF with reduced ejection fraction. Interventional strategies such as cardiac resynchronization therapy, cardiac contractility modulation, or baroreflex activation therapy might provide additional therapeutic benefits by improving symptoms and promoting reverse remodeling. Furthermore, cardiac regenerative therapies such as stem cell transplantation could become a new therapeutic resource in the management of HF. By analyzing the existing data from the literature, this review aims to evaluate the impact of new HF therapies in patients with IHD in order to gain further insight into the best form of therapeutic management for this large proportion of HF patients.

Cardioprotective Effects of a Selective c-Jun N-terminal Kinase Inhibitor in a Rat Model of Myocardial Infarction

Activation of c-Jun N-terminal kinases (JNKs) is involved in myocardial injury, left ventricular remodeling (LV), and heart failure (HF) after myocardial infarction (MI). The aim of this research was to evaluate the effects of a selective JNK inhibitor, 11H-indeno [1,2-b]quinoxalin-11-one oxime (IQ-1), on myocardial injury and acute myocardial ischemia/reperfusion (I/R) in adult male Wistar rats. Intraperitoneal administration of IQ-1 (25 mg/kg daily for 5 days) resulted in a significant decrease in myocardial infarct size on day 5 after MI. On day 60 after MI, a significant (2.6-fold) decrease in LV scar size, a 2.2-fold decrease in the size of the LV cavity, a 2.9-fold decrease in the area of mature connective tissue, and a 1.7-fold decrease in connective tissue in the interventricular septum were observed compared with the control group. The improved contractile function of the heart resulted in a significant (33%) increase in stroke size, a 40% increase in cardiac output, a 12% increase in LV systolic pressure, a 28% increase in the LV maximum rate of pressure rise, a 45% increase in the LV maximum rate of pressure drop, a 29% increase in the contractility index, a 14% increase in aortic pressure, a 2.7-fold decrease in LV end-diastolic pressure, and a 4.2-fold decrease in LV minimum pressure. We conclude that IQ-1 has cardioprotective activity and reduces the severity of HF after MI.

Prognostic impacts of β-blockers in acute coronary syndrome patients without heart failure treated by percutaneous coronary intervention

BACKGROUND

The use of β-blockers for acute coronary syndrome (ACS) patients without heart failure (HF) is controversial, and lacks of evidence in the era of reperfusion and intensive secondary preventions. This study aimed to investigate the prognostic impacts of β-blockers on patients with ACS but no HF treated by percutaneous coronary intervention (PCI).

METHODS

A total of 2397 consecutive patients with ACS but no HF treated by PCI were retrospectively recruited from January 2010 to June 2017. Univariable Cox regression was used to assess the prognostic impacts of β-blockers, followed by adjusted analysis, one-to-one propensity score matching (PSM), and inverse probability treatment weighting (IPTW) analysis, in order to control for systemic between-group differences. The primary outcome was all-cause death.

RESULTS

Among the included patients, 2060 (85.9%) were prescribed with β-blockers at discharge. The median follow-up time was 727 (433-2016) days, with 55 (2.3%) cases of all-cause death. Unadjusted analysis showed that the use of β-blockers was associated with lower risk of death (hazard ratio [HR]: 0.42, 95% confidence interval [CI]: 0.23-0.76, P = 0.004), which was sustained in adjusted analysis (HR: 0.53, 95% CI: 0.29-0.98, P = 0.044), PSM analysis (HR: 0.44, 95% CI: 0.20-0.96, P = 0.039) and IPTW analysis (HR: 0.49. 95% CI: 0.35-0.70, P < 0.001). Risk reduction was also seen in β-blocker users for cardiac death, but not for major adverse cardiovascular events.

CONCLUSIONS

The use of β-blockers was associated with reduced long-term mortality for ACS-PCI patients without HF.

Uncovering potential differentially expressed miRNAs and targeted mRNAs in myocardial infarction based on integrating analysis

Myocardial infarction (MI) is one of the leading causes of death globally. The aim of the present study was to find valuable microRNAs (miRNAs/miRs) and target mRNAs in order to contribute to our understanding of the pathology of MI. miRNA and mRNA data were downloaded for differential expression analysis. Then, a regulatory network between miRNAs and mRNAs was established, followed by function annotation of target mRNAs. Thirdly, prognosis and diagnostic analysis of differentially methylated target mRNAs were performed. Finally, an in vitro experiment was used to validate the expression of selected miRNAs and target mRNAs. A total of 19 differentially expressed miRNAs and 1,007 differentially expressed mRNAs were identified. Several regulatory interaction pairs between miRNA and mRNAs were identified, such as hsa-miR-142-2p-long-chain-fatty-acid-CoA ligase 1 (ACSL1), hsa-miR-15a-3p-nicotinamide phosphoribosyltransferase (NAMPT), hsa-miR-33b-5p-regulator of G-protein signaling 2 (RGS2), hsa-miR-17-3p-Jun dimerization protein 2 (JDP2), hsa-miR-24-1-5p-aquaporin-9 (AQP9) and hsa-miR-34a-5p-STAT1/AKT3. Of note, it was demonstrated that ACSL1, NAMPT, RGS2, JDP2, AQP9, STAT1 and AKT3 had diagnostic and prognostic values for patients with MI. In addition, STAT1 was involved in the ‘chemokine signaling pathway’ and ‘Jak-STAT signaling pathway’. AKT3 was involved in both the ‘MAPK signaling pathway’ and ‘T cell receptor signaling pathway’. Reverse transcription-quantitative PCR validation of hsa-miR-142-3p, hsa-miR-15a-3p, hsa-miR-33b-5p, ACSL1, NAMPT, RGS2 and JDP2 expression was consistent with the bioinformatics analysis. In conclusion, the identified miRNAs and mRNAs may be involved in the pathology of MI.

Overexpression of long non-coding RNA ANRIL promotes post-ischaemic angiogenesis and improves cardiac functions by targeting Akt

Angiogenesis is critical for re‐establishing the blood supply to the surviving myocardium after myocardial infarction (MI). Long non‐coding RNA ANRIL (lncRNA‐ANRIL) has been reported to regulate endothelial functions in cardiovascular diseases. This study was to determine the role of lncRNA‐ANRIL in Akt regulation and cardiac functions after MI. Human umbilical vein endothelial cells (HUVECs) were exposed to oxygen‐glucose deprivation (OGD) to mimic in vivo ischaemia. The MI model in mice was induced by ligating left anterior descending coronary artery. OGD remarkably decreased lncRNA‐ANRIL expression level, reduced the phosphorylated levels of Akt and eNOS proteins, and inhibited NO release and cell viability, which were duplicated by shRNA‐mediated gene knockdown of lncRNA‐ANRIL. Conversely, all these effects induced by OGD were abolished by adenovirus‐mediated overexpression of lncRNA‐ANRIL in HUVECs. Further, OGD impaired cell migrations and tube formations in HUVECs, which were reversed by lncRNA‐ANRIL overexpression or Akt up‐regulation. RNA immunoprecipitation analysis indicated that the affinity of lncRNA‐ANRIL to Akt protein was increased in OGD‐treated cells. In animal studies, adenovirus‐mediated lncRNA‐ANRIL overexpression increased the phosphorylated levels of Akt and eNOS, promoted post‐ischaemic angiogenesis and improved heart functions in mice with MI surgery. LncRNA‐ANRIL regulates Akt phosphorylation to improve endothelial functions, which promotes angiogenesis and improves cardiac functions in mice following MI. In this perspective, targeting lncRNA‐ANRIL/Akt may be considered to develop a drug to treat angiogenesis‐related diseases.

Action of iron chelator on intramyocardial hemorrhage and cardiac remodeling following acute myocardial infarction

Intramyocardial hemorrhage is an independent predictor of adverse outcomes in ST-segment elevation myocardial infarction (STEMI). Iron deposition resulting from ischemia-reperfusion injury (I/R) is pro-inflammatory and has been associated with adverse remodeling. The role of iron chelation in hemorrhagic acute myocardial infarction (AMI) has never been explored. The purpose of this study was to investigate the cardioprotection offered by the iron-chelating agent deferiprone (DFP) in a porcine AMI model by evaluating hemorrhage neutralization and subsequent cardiac remodeling. Two groups of animals underwent a reperfused AMI procedure: control and DFP treated (N = 7 each). A comprehensive MRI examination was performed in healthy state and up to week 4 post-AMI, followed by histological assessment. Infarct size was not significantly different between the two groups; however, the DFP group demonstrated earlier resolution of hemorrhage (by T2* imaging) and edema (by T2 imaging). Additionally, ventricular enlargement and myocardial hypertrophy (wall thickness and mass) were significantly smaller with DFP, suggesting reduced adverse remodeling, compared to control. The histologic results were consistent with the MRI findings. To date, there is no effective targeted therapy for reperfusion hemorrhage. Our proof-of-concept study is the first to identify hemorrhage-derived iron as a therapeutic target in I/R and exploit the cardioprotective properties of an iron-chelating drug candidate in the setting of AMI. Iron chelation could potentially serve as an adjunctive therapy in hemorrhagic AMI.

Renal denervation attenuates pressure overload-induced cardiac remodelling in rats with biphasic regulation of autophagy

AIM

This study aimed to investigate effects of renal denervation (RDN) on pressure overload-induced cardiac remodelling in rats and the related mechanisms.

METHODS

Adult male Sprague-Dawley rats underwent transverse aortic constriction (TAC) to generate cardiac remodelling. RDN was performed 1 week after TAC. The animals were divided into four groups: control group, TAC group, TAC+RDN group and control+RDN group. Rats in all groups were studied at 3 and 10 weeks after TAC respectively. Echocardiography and histology were used to evaluate cardiac function and pathological changes. TUNEL staining and western blotting were used to assess apoptosis. Western blotting and transmission electron microscopy (TEM) were used to evaluate autophagy.

RESULTS

Three weeks after TAC, the TAC rats exhibited cardiac hypertrophy with normal cardiac function and no myocardial interstitial fibrosis or apoptosis, accompanied by a lower LC3 II level and fewer autophagic vacuoles in the left ventricles, both in the presence and absence of chloroquine (CQ), indicating suppressed autophagy at this stage. RDN ameliorated these pathological changes and attenuated the decrease in autophagy. Ten weeks after TAC, the TAC rats had decreased cardiac function, obvious cardiac interstitial fibrosis and apoptosis, with increased autophagy. RDN prevented these pathological changes, coincident with attenuation of increased autophagy.

CONCLUSION

Autophagy was suppressed at the early stage but activated at the late stage of TAC-induced cardiac remodelling. RDN attenuated the pathological changes of TAC rats, accompanied by attenuation of the changes in autophagy. Thus, RDN ameliorated TAC-induced cardiac remodelling partially associated with biphasic modulation of autophagy.

Relationship Between Patterns in Antihypertensive Drugs Medication and Mortality in Incident Dialysis Patients: A Multicenter Prospective Cohort Study

Hypertension is common in patients with chronic kidney disease. Whether blood pressure management before dialysis initiation influences prognosis during maintenance dialysis remains unclear. Hence, we surveyed the status of antihypertensive drug use in incident dialysis patients. Moreover, we examined the association between antihypertensive drug use patterns at the time of dialysis initiation and mortality. We used a database derived from the multicenter prospective Aichi Cohort Study of Prognosis in Patients Newly Initiated into Dialysis, which included 1520 incident dialysis patients in Aichi prefecture, Japan. The baseline in the present study was set as the time of dialysis initiation. We examined antihypertensive drug prescription patterns at baseline, as well as the association between use of antihypertensive drugs and mortality after dialysis initiation. Among all participants, 1440 were taking at least one antihypertensive drug. The rate of calcium channel blocker (CCB) use was highest, accounting for 74.3%. CCB use was significantly associated with lower all-cause and cardiovascular-related mortality (hazard ratio [HR]: 0.62 and 0.57, 95% confidence interval [CI]: 0.46-0.85 and [0.35-0.91], respectively). Compared with no use of either drug, combination therapy with a renin angiotensin system blocker (RASB) and CCB was significantly associated with lower mortality (HR: 0.51, 95% CI: 0.34-0.76). The present study demonstrated that antihypertensive drugs were used in 95% of incident dialysis patients. In addition, use of a CCB and combination therapy with a CCB and RASB at the time of dialysis initiation was associated with lower mortality during maintenance dialysis.

Endogenous reduction of miR-185 accelerates cardiac function recovery in mice following myocardial infarction via targeting of cathepsin K

Angiogenesis is critical for re‐establishing the blood supply to the surviving myocardium after myocardial infarction (MI) in patients with acute coronary syndrome (ACS). MicroRNAs are recognised as important epigenetic regulators of endothelial function. The aim of this study was to determine the roles of microRNAs in angiogenesis. Eighteen circulating microRNAs including miR‐185‐5p were differently expressed in plasma from patients with ACS by high‐throughput RNA sequencing. The expressional levels of miR‐185‐5p were dramatically reduced in hearts isolated from mice following MI and cultured human umbilical vein endothelial cells (HUVECs) under hypoxia, as determined by fluorescence in situ hybridisation and quantitative RT‐PCR. Evidence from computational prediction and luciferase reporter gene activity indicated that cathepsin K (CatK) mRNA is a target of miR‐185‐5p. In HUVECs, miR‐185‐5p mimics inhibited cell proliferations, migrations and tube formations under hypoxia, while miR‐185‐5p inhibitors performed the opposites. Further, the inhibitory effects of miR‐185‐5p up‐regulation on cellular functions of HUVECs were abolished by CatK gene overexpression, and adenovirus‐mediated CatK gene silencing ablated these enhancive effects in HUVECs under hypoxia. In vivo studies indicated that gain‐function of miR‐185‐5p by agomir infusion down‐regulated CatK gene expression, impaired angiogenesis and delayed the recovery of cardiac functions in mice following MI. These actions of miR‐185‐5p agonists were mirrored by in vivo knockdown of CatK in mice with MI. Endogenous reductions of miR‐185‐5p in endothelial cells induced by hypoxia increase CatK gene expression to promote angiogenesis and to accelerate the recovery of cardiac function in mice following MI.

Biomaterials and heart recovery: cardiac repair, regeneration and healing in the MCS era: a state of the "heart"

Regenerative medicine is an emerging interdisciplinary field of scientific research that, supported by tissue engineering is, nowadays, a valuable and reliable solution dealing with the actual organs shortage and the unresolved limits of biological or prosthetic materials used in repair and replacement of diseased or damaged human tissues and organs. Due to the improvements in design and materials, and to the changing of clinical features of patients treated for valvular heart disease the distance between the ideal valve and the available prostheses has been shortened. We will then deal with the developing of new tools aiming at replacing or repair cardiac tissues that still represent an unmet clinical need for the surgeons and indeed for their patients. In the effort of improving treatment for the cardiovascular disease (CVD), scientists struggle with the lack of self-regenerative capacities of finally differentiated cardiovascular tissues. In this context, using several converging technological approaches, regenerative medicine moves beyond traditional transplantation and replacement therapies and can restore tissue impaired function. It may also play an essential role in surgery daily routine, leading to produce devices such as injectable hydrogels, cardiac patches, bioresorbable stents and vascular grafts made by increasingly sophisticated biomaterial scaffolds; tailored devices promptly fabricated according to surgeon necessity and patient anatomy and pathology will hopefully represent a daily activity in the next future. The employment of these devices, still far from the in vitro reproduction of functional organs, has the main aim to achieve a self-renewal process in damaged tissues simulating endogenous resident cell populations. In this field, the collaboration and cooperation between cardiothoracic surgeons and bioengineers appear necessary to modify these innovative devices employed in preclinical studies according to the surgeon's needs.

Analysis of microRNA Expression Profiles Induced by Yiqifumai Injection in Rats with Chronic Heart Failure

Background: Yiqifumai Injection (YQFM) is clinically used to treat various cardiovascular diseases including chronic heart failure (CHF). The efficacy of YQFM for treating heart failure has been suggested, but the mechanism of action for pharmacological effects of YQFM is unclear. Methods: Echocardiography detection, left ventricular intubation evaluation, histopathology and immunohistochemical examination were performed in CHF rats to evaluate the cardioprotective effect of YQFM. Rat miRNA microarray and bioinformatics analysis were employed to investigate the differentially expressed microRNAs. In vitro models of AngII-induced hypertrophy and t-BHP induced oxidative stress in H9c2 myocardial cells were used to validate the anti-hypertrophy and anti-apoptosis effects of YQFM. Measurement of cell surface area, ATP content and cell viability, Real-time PCR and Western blot were performed. Results: YQFM significantly improved the cardiac function of CHF rats by increasing left ventricular ejection fraction and fractional shortening, decreasing left ventricular internal diameter and enhancing cardiac output. Seven microRNAs which have a reversible regulation by YQFM treatment were found. Among them, miR-21-3p and miR-542-3p are related to myocardial hypertrophy and cell proliferation, respectively and were further verified by RT-PCR. Target gene network was established and potential related signaling pathways were predicted. YQFM could significantly alleviate AngII induced hypertrophy in cellular model. It also significantly increased cell viabilities and ATP content in t-BHP induced apoptotic cell model. Western blot analysis showed that YQFM could increase the phosphorylation of Akt. Conclusion: Our findings provided scientific evidence to uncover the mechanism of action of YQFM on miRNAs regulation against CHF by miRNA expression profile technology. The results indicated that YQFM has a potential effect on alleviate cardiac hypertrophy and apoptosis in chronic heart failure.

MicroRNAs as predictive biomarkers for myocardial injury in aged mice following myocardial infarction

The occurrence of myocardial infarction (MI) increases appreciably with age. In the Framingham Heart Study, the incidence of MI more than doubles for men and increases more than five-fold in women (ages 55-64 years compared to 85-94 years). MicroRNAs (miRNAs) quantitatively regulate their target's expression post-transcriptionally by either silencing action through binding at the 3'UTR domains or degrading the messages at their coding regions. In either case, these regulations affect the cardiac transcriptional output and cardiac function. Among the known cardiac associated miRNA, miRNA-1, miRNA-133a, and miRNA-34a have been shown to induce adverse structural remodeling to impair cardiac contractile function. In the present study, an in vivo model of MI in young (3 month) and old (22 month) mice is used to investigate the possible role whereby these three miRNAs exert negative effects on heart function following MI. Herein we demonstrate that in older mouse heart, all three microRNAs show increased levels of expression, while miRNA-1 shows a further increase in old mouse heart following MI, which corresponds to left ventricular (LV) wall thinning. These structural changes in cardiac tissue may causes downstream LV dilation and subsequent LV dysfunction. Results presented here suggest that significantly elevated levels of miRNA-1 in post-MI old heart could be predictive of cardiac injury in older mice as the high risk biomarker for MI in older individuals.

Transforming Growth Factor-β Receptor III is a Potential Regulator of Ischemia-Induced Cardiomyocyte Apoptosis

Background

Myocardial infarction (MI) is often accompanied by cardiomyocyte apoptosis, which decreases heart function and leads to an increased risk of heart failure. The aim of this study was to examine the effects of transforming growth factor‐β receptor III (TGFβR3) on cardiomyocyte apoptosis during MI.

Methods and Results

An MI mouse model was established by left anterior descending coronary artery ligation. Cell viability, apoptosis, TGFβR3, and mitogen‐activated protein kinase signaling were assessed by methylthiazolyldiphenyl‐tetrazolium bromide assay, terminal deoxynucleotidyl transferase‐mediated dUTP nick end labeling assay, immunofluorescence, electron microscopy, and Western blotting. Our results demonstrated that TGFβR3 expression in the border region of the heart was dynamically changed during MI. After stimulation with H₂O₂, TGFβR3 overexpression in cardiomyocytes led to increased cell apoptosis and activation of p38 signaling, whereas TGFβR3 knockdown had the opposite effect. ERK1/2 and JNK1/2 signaling was not altered by TGFβR3 modulation, and p38 inhibitor (SB203580) reduced the effect of TGFβR3 on apoptosis, suggesting that p38 has a nonredundant function in activating apoptosis. Consistent with the in vitro observations, cardiac TGFβR3 transgenic mice showed augmented cardiomyocyte apoptosis, enlarged infarct size, increased injury, and enhanced p38 signaling upon MI. Conversely, cardiac loss of function of TGFβR3 by adeno‐associated viral vector serotype 9–TGFβR3 short hairpin RNA attenuated the effects of MI in mice.

Conclusions

TGFβR3 promotes apoptosis of cardiomyocytes via a p38 pathway–associated mechanism, and loss of TGFβR3 reduces MI injury, which suggests that TGFβR3 may serve as a novel therapeutic target for MI.

Myeloperoxidase Inhibition Improves Ventricular Function and Remodeling After Experimental Myocardial Infarction

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The inflammatory enzyme MPO is a potential therapeutic target in cardiovascular diseases.

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PF-1355 is an orally bioavailable mechanism-based inhibitor of MPO enzymatic activity. PF-1355 treatment successfully inhibited MPO in mouse models of myocardial infarction and ischemia reperfusion injury.

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Short duration oral drug treatment for 7 days attenuated inflammation and cardiac dilation during early infarct healing. However, MPO-containing cells persisted beyond 7 days.

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Prolonged 21-day treatment improved ejection fraction (∼44%) and decreased end-diastolic volume (∼53%) and left ventricular mass (∼33%) compared with untreated control subjects.

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Better therapeutic effect was also achieved when treatment was started early (at 1 h) after the initial ischemic insult.

PF-1355 is an oral myeloperoxidase (MPO) inhibitor that successfully decreased elevated MPO activity in mouse myocardial infarction models. Short duration PF-1355 treatment for 7 days decreased the number of inflammatory cells and attenuated left ventricular dilation. Cardiac function and remodeling improved when treatment was increased to 21 days. Better therapeutic effect was further achieved with early compared with delayed treatment initiation (1 h vs. 24 h after infarction). In conclusion, PF-1355 treatment protected a mouse heart from acute and chronic effects of MI, and this study paves the way for future translational studies investigating this class of drugs in cardiovascular diseases.

Cardiac fibroblast cytokine profiles induced by proinflammatory or profibrotic stimuli promote monocyte recruitment and modulate macrophage M1/M2 balance in vitro

Macrophage polarization plays an essential role in cardiac remodeling after injury, evolving from an initial accumulation of proinflammatory M1 macrophages to a greater balance of anti-inflammatory M2 macrophages. Whether cardiac fibroblasts themselves influence this process remains an intriguing question. In this work, we present evidence for a role of cardiac fibroblasts (CF) as regulators of macrophage recruitment and skewing. Adult rat CF, were treated with lipopolysaccharide (LPS) or TGF-β1, to evaluate ICAM-1 and VCAM-1 expression using Western blot and proinflammatory/profibrotic cytokine secretion using LUMINEX. We performed in vitro migration and adhesion assays of rat spleen monocytes to layers of TGF-β1- or LPS-pretreated CF. Finally, TGF-β1- or LPS-pretreated CF were co-cultured with monocyte, to evaluate their effects on macrophage polarization, using flow cytometry and cytokine secretion. There was a significant increase in monocyte adhesion to LPS- or TGF-β1-stimulated CF, associated with increased CF expression of ICAM-1 and VCAM-1. siRNA silencing of either ICAM-1 or VCAM-1 inhibited monocyte adhesion to LPS-pretreated CF; however, monocyte adhesion to TGF-β1-treated CF was dependent on only VCAM-1 expression. Pretreatment of CF with LPS or TGF-β1 increased monocyte migration to CF, and this effect was completely abolished with an MCP-1 antibody blockade. LPS-treated CF secreted elevated levels of TNF-α and MCP-1, and when co-cultured with monocyte, LPS-treated CF stimulated increased macrophage M1 polarization and secretion of proinflammatory cytokines (TNF-α, IL-12 and MCP-1). On the other hand, CF stimulated with TGF-β1 produced an anti-inflammatory cytokine profile (high IL-10 and IL-5, low TNF-α). When co-cultured with monocytes, the TGF-β1 stimulated fibroblasts skewed monocyte differentiation towards M2 macrophages accompanied by increased IL-10 and decreased IL-12 levels. Taken together, our results show for the first time that CF can recruit monocytes (via MCP-1-mediated chemotaxis and adhesion to ICAM-1/VCAM-1) and induce their differentiation to M1 or M2 macrophages (through the CF cytokine profile induced by proinflammatory or profibrotic stimuli).

Activin A Predicts Left Ventricular Remodeling and Mortality in Patients with ST-Elevation Myocardial Infarction

BACKGROUND

Activin A levels increase in a variety of heart diseases including ST-elevation myocardial infarction (STEMI). The aim of this study is to investigate whether the level of activin A can be beneficial in predicting left ventricular remodeling, heart failure, and death in patients with ST-elevation myocardial infarction (STEMI).

METHODS

We enrolled 278 patients with STEMI who had their activin A levels measured on day 2 of hospitalization. Echocardiographic studies were performed at baseline and were repeated 6 months later. Thereafter, the clinical events of these patients were followed for a maximum of 3 years, including all-cause death and readmission for heart failure.

RESULTS

During hospitalization, higher activin A level was associated with higher triglyceride level, lower left ventricular ejection fraction (LVEF), and lower left ventricular end diastolic ventricular volume index (LVEDVI) in multivariable linear regression model. During follow-up, patients with activin A levels > 129 pg/ml had significantly lower LVEF, and higher LVEDVI at 6 months. Kaplan-Meier survival curves showed that activin A level > 129 pg/ml was a predictor of all-cause death (p = 0.022), but not a predictor of heart failure (p = 0.767).

CONCLUSIONS

Activin A level > 129 pg/ml predicts worse left ventricular remodeling and all-cause death in STEMI.

TVP1022: A Novel Cardioprotective Drug Attenuates Left Ventricular Remodeling After Ischemia/Reperfusion in Pigs

BACKGROUND

The current cornerstone treatment of myocardial infarction (MI) is restoration of coronary blood flow by means of thrombolytic therapy or primary percutaneous coronary intervention. However, reperfusion of ischemic myocardium can actually provoke tissue damage, defined as "ischemia-reperfusion (I/R) injury." TVP1022 [the S-isomer of rasagiline (Azilect), FDA-approved anti-Parkinson's drug] was found to exert cardioprotective activities against various cardiac insults, such as chronic heart failure and I/R, in rat models. Therefore, we tested the hypothesis that TVP1022 will provide cardioprotection against I/R injury and post-MI remodeling in a pig model.

METHODS

For inducing MI, we used an I/R model of midleft anterior descending artery occlusion for 90 minutes followed by follow-up for 8 weeks in 18 farm pigs (9 pigs in each group, MI + TVP1022 or MI + Vehicle). Echocardiographic measurements were performed and cardiac scar size was calculated using histopathological methods. For fibrosis evaluation, we measured the interstitial collagen volume fraction in the remote noninfarcted tissue.

RESULTS

TVP1022 administration significantly decreased cardiac scar size, attenuated left ventricular dilation, and improved cardiac function assessed by segmental circumferential strain analysis. Furthermore, TVP1022 significantly reduced myocardial fibrosis 8 weeks post-MI.

CONCLUSIONS

Collectively, these findings indicate that TVP1022 provides prominent cardioprotection against I/R injury and post-MI remodeling in this I/R pig model.

NDP-α-MSH attenuates heart and liver responses to myocardial reperfusion via the vagus nerve and JAK/ERK/STAT signaling

Melanocortin peptides afford cardioprotection during myocardial ischemia/reperfusion via janus kinases (JAK), extracellular signal-regulated kinases (ERK) and signal transducers/activators of transcription (STAT) pathways. Here we investigated whether melanocortin-induced modulation of the JAK/ERK/STAT signaling occurs via the cholinergic anti-inflammatory pathway, focusing our study on cardiac and hepatic responses to prolonged myocardial ischemia/reperfusion. Ischemia was produced in rats by ligature of the left anterior descending coronary artery for 30min; effects of ischemia/reperfusion were evaluated using Western blot of heart and liver proteins. Intravenous treatment, during coronary artery occlusion, with the melanocortin analog (Nle(4), D-Phe(7))α-melanocyte-stimulating hormone (NDP-α-MSH) induced a left ventricle up-regulation of the cardioprotective transcription factors pJAK2, pERK1/2 and pTyr-STAT3 (JAK-dependent), and a reduction in the levels of the inflammatory mediators tumor necrosis factor-α (TNF-α) and pJNK (a transcription factor also involved in apoptosis), as assessed at the end of the 2-h reperfusion period. Further, these beneficial effects of NDP-α-MSH were associated with heart over-expression of the pro-survival proteins heme oxygenase-1 (HO-1) and Bcl-XL, and decrease of ventricular arrhythmias and infarct size. In the liver NDP-α-MSH induced a decrease in the pJAK2 and pTyr-STAT3 levels, and strongly reduced pERK1/2 expression. In the liver of ischemic rats NDP-α-MSH also blunted pJNK activity and TNF-α expression, and up-regulated Bcl-XL. Bilateral cervical vagotomy prevented all effects of NDP-α-MSH, both in the heart and liver. These results indicate that melanocortins inhibit heart and liver damage triggered by prolonged myocardial ischemia/reperfusion likely, as main mechanism, via the vagus nerve-mediated modulation of the JAK/STAT/ERK signaling pathways.

Gene expression profiling of CD133-positive cells in coronary artery disease

Gene expression profiles of CD133-positive cells from patients with coronary artery disease (CAD) were analyzed to identify key genes associated with cardiac therapy. Furthermore, the effect of exercise on gene expression was also investigated. Gene expression data set (accession number: GSE18608) was downloaded from the Gene Expression Omnibus, including blood samples from four healthy subjects (H), and from 10 patients with coronary artery disease at baseline (B) and after 3 months (3M) of exercise. Differential analysis was performed for H vs. B and H vs. 3M using limma package of R. Two‑way cluster analysis was performed using the expression levels of the differentially expressed genes (DEGs) by package pheatmap of R. Functional enrichment analysis was applied on the DEGs using the Database for Annotation, Visualization and Integrated Discovery. Relevant small molecules were predicted using the Connectivity map database (cMap). A total of 131 and 71 DEGs were identified in patients with CAD prior to and following 3 months of exercise. The two groups of DEGs were compared and 44 genes overlapped. In cluster analysis with the expression levels of the common DEGs, patients with CAD could be well separated from the healthy controls. Functional enrichment analysis showed that response to peptide hormone stimulus and anti‑apoptosis pathways were significantly enriched in the common DEGs. A total of 12 relevant small molecules were revealed by cMap based upon the expression levels of common DEGs, such as 5252917 and MG‑262. Three months of exercise in part normalized the gene expression in CAD patients. The genes not altered by exercise may be the targets of small molecules, such as 5252917 and MG-262.

Bendavia, a mitochondria-targeting peptide, improves postinfarction cardiac function, prevents adverse left ventricular remodeling, and restores mitochondria-related gene expression in rats

AB We evaluated the post-myocardial infarction (MI) therapeutic effects of Bendavia. Two hours after coronary artery ligation, rats were randomized to receive chronic Bendavia treatment (n = 28) or water (n = 26). Six weeks later, Bendavia significantly reduced scar circumference (39.7% +/- 2.2%) compared with water treatment (47.4% +/- 0.03%, P = 0.024) and reduced left ventricular (LV) volume by 8.9% (P = 0.019). LV fractional shortening was significantly improved by Bendavia (28.8% +/- 1.7%) compared with water treatment (23.8% +/- 1.8%, P = 0.047). LV ejection fraction was higher with Bendavia (55.3% +/- 1.4%) than water treatment (49.3% +/- 1.4%, P = 0.005). Apoptosis, within the MI border zone, was significantly less in the Bendavia group (32% +/- 3%, n = 12) compared with the water group (41% +/- 2%, n = 12; P = 0.029). Bendavia reversed mitochondrial function-related gene expression in the MI border, which was largely reduced in water-treated rats. Bendavia improved complex-I and -IV activity, and reduced production of reactive oxygen species and cytosolic cytochrome c level in the peri-infarcted region. Bendavia improved post-MI cardiac function, prevented infarct expansion and adverse LV remodeling, and restored mitochondria-related gene expression, complex-I and -IV activity, and reduced reactive oxygen species and cardiomyocyte apoptosis in the noninfarcted MI border.

What can we learn about treating heart failure from the heart's response to acute exercise? Focus on the coronary microcirculation

Coronary microvascular function and cardiac function are closely related in that proper cardiac function requires adequate oxygen delivery through the coronary microvasculature. Because of the close proximity of cardiomyocytes and coronary microvascular endothelium, cardiomyocytes not only communicate their metabolic needs to the coronary microvasculature, but endothelium-derived factors also directly modulate cardiac function. This review summarizes evidence that the myocardial oxygen balance is disturbed in the failing heart because of increased extravascular compressive forces and coronary microvascular dysfunction. The perturbations in myocardial oxygen balance are exaggerated during exercise and are due to alterations in neurohumoral influences, endothelial function, and oxidative stress. Although there is some evidence from animal studies that the myocardial oxygen balance can partly be restored by exercise training, it is largely unknown to what extent the beneficial effects of exercise training include improvements in endothelial function and/or oxidative stress in the coronary microvasculature and how these improvements are impacted by risk factors such as diabetes, obesity, and hypercholesterolemia.

Angiotensin Ⅱ Activates MCP-1 and Induces Cardiac Hypertrophy and Dysfunction via Toll-like Receptor 4

AIM

Angiotensin Ⅱ(Ang Ⅱ) produces reactive oxygen species (ROS), thus contributing to the development of cardiac hypertrophy and subsequent heart failure, and stimulates the expression of monocyte chemoattractant protein-1 (MCP-1). In addition, Toll-like receptor 4 (TLR4) is involved in the upregulation of MCP-1. In order to clarify whether TLR4 is involved in the onset of cardiac dysfunction caused by Ang Ⅱ stimulation, we investigated the effects of TLR4 on oxidative stress, the MCP-1 expression and cardiac dysfunction in mice with Ang Ⅱ-induced hypertension.

METHODS

TLR4-deficient (Tlr4(lps-d)) and wild-type (WT) mice were randomized into groups treated with Ang Ⅱ, norepinephrine (NE) or a subdepressor dose of the Ang Ⅱreceptor blocker irbesartan (IRB) and Ang Ⅱ for two weeks.

RESULTS

Ang Ⅱ and NE similarly increased systolic blood pressure in all drug-treated groups compared to that observed in the control group among both WT and Tlr4(lps-d) mice (p＜0.05). In the WT mice, Ang Ⅱ induced cardiac hypertrophy as well as vascular remodeling and perivascular fibrosis of the intramyocardial arteries and monocyte/macrophage infiltration in the heart (p＜0.05). Furthermore, Ang Ⅱ treatment decreased the left ventricular diastolic function and resulted in a greater left ventricular end-systolic dimension (p＜0.05) in addition to producing a five-fold increase in the NADPH oxidase activity, ROS content and MCP-1 expression (p＜0.05). In contrast, the Tlr4(lps-d) mice showed little effects of Ang Ⅱ on these indices. In the WT mice, IRB treatment reversed these changes compared to that seen in the mice treated with Ang Ⅱ alone. NE produced little effect on any of the indices in either the WT or Tlr4(lps-d) mice.

CONCLUSIONS

TLR4 may be involved in the processes underlying the increased oxidative stress, selectively activated MCP-1 expression and cardiac hypertrophy and dysfunction seen in cases of Ang Ⅱ- induced hypertension.

Fibrosis and heart failure

The extracellular matrix (ECM) is a living network of proteins that maintains the structural integrity of the myocardium and allows the transmission of electrical and mechanical forces between the myocytes for systole and diastole. During ventricular remodeling, as a result of iterations in the hemodynamic workload, collagen, the main component of the ECM, increases and occupies the areas between the myocytes and the vessels. The resultant fibrosis (reparative fibrosis) is initially a compensatory mechanism and may progress adversely influencing tissue stiffness and ventricular function. Replacement fibrosis appears at sites of previous cardiomyocyte necrosis to preserve the structural integrity of the myocardium, but with the subsequent formation of scar tissue and widespread distribution, it has adverse functional consequences. Continued accumulation of collagen impairs diastolic function and compromises systolic mechanics. Nevertheless, the development of fibrosis is a dynamic process wherein myofibroblasts, the principal cellular elements of fibrosis, are not only metabolically active and capable of the production and upregulation of cytokines but also have contractile properties. During the process of reverse remodeling with left ventricular assist device unloading, cellular, structural, and functional improvements are observed in terminal heart failure patients. With the advent of anti-fibrotic pharmacologic therapies, cellular therapy, and ventricular support devices, fibrosis has become an important therapeutic target in heart failure patients. Herein, we review the current concepts of fibrosis as a main component of ventricular remodeling in heart failure patients. Our aim is to integrate the histopathologic process of fibrosis with the neurohormonal, cytochemical, and molecular changes that lead to ventricular remodeling and its physiologic consequences in patients. The concept of fibrosis as living scar allows us to envision targeting this scar as a means of improving ventricular function in heart failure patients.

Effects of N-acetylcysteine on the cardiac remodeling biomarkers and major adverse events following acute myocardial infarction: a randomized clinical trial

AIMS

The aims of this study were to evaluate the effects of N-acetylcysteine (NAC) on cardiac remodeling and major adverse events following acute myocardial infarction (AMI).

METHODS

In a prospective, double-blind, randomized clinical trial, the effect of NAC on the serum levels of cardiac biomarkers was compared with that of placebo in 98 patients with AMI. Also, the patients were followed up for a 1-year period for major adverse cardiac events (MACE), including the occurrence of recurrent myocardial infarction, death, and need for target vessel revascularization.

RESULTS

In patients who received NAC, the serum levels of matrix metalloproteinase (MMP)-9 and MMP-2 after 72 h were significantly lower than those in the placebo group (p = 0.014 and p = 0.045, respectively). The length of hospitalization in patients who received NAC was significantly shorter than that in the placebo group (p = 0.024). With respect to MACE, there was a significant difference between those who received NAC (14 %) and those patients on placebo (25 %) (p = 0.024). Re-infarction took place in 4 % of patients in the NAC group as compared with 16.7 % in patients who received placebo (p = 0.007).

CONCLUSION

NAC can be beneficial in preventing early remodeling by reducing the level of MMP-2 and MMP-9. Moreover, NAC decreased the length of hospital stays in patients after AMI. By decreasing MACE, NAC could possibly be introduced as a 'magic bullet' in the pharmacotherapy of patients with AMI. Further studies are needed to elucidate NAC's role in this population.

Ketanserin improves cardiac performance after myocardial infarction in spontaneously hypertensive rats partially through restoration of baroreflex function

AIM

Baroreflex dysfunction is associated with a higher rate of sudden death after myocardial infarction (MI). Ketanserin enhances baroreflex function in rats. The present work was designed to examine whether ketanserin improves the post-MI cardiac function and to explore the possible mechanism involved.

METHODS

Spontaneously hypertensive rats (SHR) were treated with ketanserin (0.3 mg·kg(-1)·d(-1)). Two weeks later, blood pressure and baroreflex function were measured, followed by a ligation of the left coronary artery. The expressions of vesicular acetylcholine transporter (VAChT) and α7 nicotinic acetylcholine receptor (α7-nAChR) in ischemic myocardium, angiogenesis, cardiac function, and left ventricular (LV) remodeling were evaluated subsequently.

RESULTS

Ketanserin significantly improved baroreflex sensitivity (0.62±0.21 vs 0.34±0.12 ms/mmHg, P<0.01) and vagal tonic activity (heart rate changes in response to atropine, 54.8±16.2 vs 37.6±13.4 bpm, P<0.01) without affecting the blood pressure or basic heart rate in SHR. Treatment of SHR with ketanserin prominently improved cardiac function and alleviated LV remodeling, as reflected by increases in the ejection fraction, fractional shortening, and LV systolic pressure as well as decreases in LV internal diameter and LV relative weight. The capillary density, vascular endothelial growth factor expression, and blood flow in the ischemic myocardium were significantly higher in the ketanserin-treated group. In addition, ketanserin markedly increased the expression of VAChT and α7-nAChR in ischemic myocardium.

CONCLUSION

Ketanserin improved post-MI cardiac function and angiogenesis in ischemic myocardium. The findings provide a mechanistic basis for restoring baroreflex function using ketanserin in the treatment of MI.

Antagonist molecules in the treatment of angina

INTRODUCTION

Management of chronic angina has evolved dramatically in the last few decades with several options for pharmacotherapy outlined in various evidence-based guidelines.

AREAS COVERED

There is a growing list of drugs that are currently being investigated for treatment of chronic angina. These also include several herbal medications, which are now being scientifically evaluated as potential alternative or even adjunctive therapy for angina. Gene- and cell-based therapies have opened yet another avenue for management of chronic refractory angina in 'no-option' patients who are not candidates for either percutaneous or surgical revascularization and are on optimal medical therapy. An extensive review of literature using PUBMED, Cochrane database, clinical trial databases of the USA and European Union was done and summarized in this review. This review will attempt to discuss the traditional as well as novel therapeutic agents for angina.

EXPERT OPINION

Several pharmacological and non-pharmacological therapeutic options are now available for treatment and management of chronic refractory angina. Renewed interest in traditional therapies and cell- and gene-based modalities with targeted drug delivery systems will open the doors for personalized therapy for patients with chronic refractory angina.

Co-treatment with conjugated linoleic acid and nitrite protects against myocardial infarction

According to the CDC, the most common type of heart disease is coronary artery disease, which commonly leads to myocardial infarction (MI). Therapeutic approaches to lessen the resulting cardiovascular injury associated with MI are limited. Recently, MicroRNAs (miRNAs) have been shown to act as negative regulators of gene expression by inhibiting mRNA translation and/or stimulating mRNA degradation. A single miRNA can modulate physiological or disease phenotypes by regulating whole functional systems. Importantly, miRNAs can regulate cardiac function, thereby modulating heart muscle contraction, heart growth and morphogenesis. MicroRNA-499 (miRNA-499) is a cardiac-specific miRNA that when elevated causes cardiomyocyte hypertrophy, in turn preventing cardiac dysfunction during MI. Previous studies revealed that combination treatment with conjugated linoleic acid (cLA) and nitrite preserved cardiovascular function in mice. Therefore, it was hypothesized that cLA and nitrite may regulate miRNA-499, thus providing cardiac protection during MI. To test this hypothesis, 12-week old mice were treated with cLA (10 mg/kg/d-via osmotic mini-pump) or cLA and nitrite (50 ppm-drinking water) 3 days prior to MI (ligation of the left anterior descending artery). Echocardiography and pressure–volume (PV)-loop analysis revealed that cLA and nitrite-treated MI mice had improved heart function (10 days following MI) compared to untreated MI mice. Treatment with cLA and nitrite significantly induced levels of miRNA-499 compared to untreated MI mice. In addition, treatment with cLA and nitrite abolished MI-induced protein expression of p53 and dynamin-related protein-1 (DRP-1). Moreover, the antioxidant enzyme expression of heme oxygenase-1 (HO-1) was elevated in MI mice treated with cLA and nitrite compared to untreated MI mice. Confocal imaging on heart tissue confirmed expression the levels of HO-1 and p53. Taken together, these results suggest that therapeutic treatment with cLA and nitrite may provide significant protection during MI through regulation of both cardiac specific miRNA-499 and upregulation of phase 2 antioxidant enzyme expression.

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Co-treatment with cLA and nitrite increases cardiac specific miRNA-499, leading to cardioprotection in MI.

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MI-induced p53 and DRP-1 expression is abolished with cLA and nitrite treatment.

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HO-1 expression following treatment with cLA and nitrite is cardioprotective.

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Modulation of miR-499 may represent a therapeutic approach to treat apoptosis-related cardiac disease, including MI.

Treatment with the CC chemokine-binding protein Evasin-4 improves post-infarction myocardial injury and survival in mice

Chemokines trigger leukocyte trafficking and are implicated in cardiovascular disease pathophysiology. Chemokine-binding proteins, called "Evasins" have been shown to inhibit both CC and CXC chemokine-mediated bioactivities. Here, we investigated whether treatment with Evasin-3 (CXC chemokine inhibitor) and Evasin-4 (CC chemokine inhibitor) could influence post-infarction myocardial injury and remodelling. C57Bl/6 mice were submitted in vivo to left coronary artery permanent ligature and followed up for different times (up to 21 days). After coronary occlusion, three intraperitoneal injections of 10 μg Evasin-3, 1 μg Evasin-4 or equal volume of vehicle (PBS) were performed at 5 minutes, 24 hours (h) and 48 h after ischaemia onset. Both anti-chemokine treatments were associated with the beneficial reduction in infarct size as compared to controls. This effect was accompanied by a decrease in post-infarction myocardial leukocyte infiltration, reactive oxygen species release, and circulating levels of CXCL1 and CCL2. Treatment with Evasin-4 induced a more potent effect, abrogating the inflammation already at one day after ischaemia onset. At days 1 and 21 after ischaemia onset, both anti-chemokine treatments failed to significantly improve cardiac function, remodelling and scar formation. At 21-day follow-up, mouse survival was exclusively improved by Evasin-4 treatment when compared to control vehicle. In conclusion, we showed that the selective inhibition of CC chemokines (i.e. CCL5) with Evasin-4 reduced cardiac injury/inflammation and improved survival. Despite the inhibition of CXC chemokine bioactivities, Evasin-3 did not affect mouse survival. Therefore, early inhibition of CC chemokines might represent a promising therapeutic approach to reduce the development of post-infarction heart failure in mice.

Cardioprotective effects of the YiQiFuMai injection and isolated compounds on attenuating chronic heart failure via NF-κB inactivation and cytokine suppression

ETHNOPHARMACOLOGICAL RELEVANCE

The YiQiFuMai injection (YQFM) is a traditional Chinese medicine for the treatment of chronic heart failure (CHF). The present study not only evaluated the cardioprotective effect and anti-inflammatory mechanism of the YQFM injection in an experimental model of CHF but also investigated its bioactive constituents in vitro.

MATERIALS AND METHODS

The left anterior descending coronary artery (LAD) in rats was ligated to make an animal model of CHF. From this, electrocardiographic parameters and exterior signs of rat hearts were recorded. Additionally, the histopathology of heart tissues was examined, and parameters of inflammatory stress were measured. Experiments were performed over two months in LAD-ligation rats treated with YQFM or vehicle. Treatment with Captopril was used as a positive control, which has previously been shown to prevent CHF, and rats without LAD-ligation were used as a negative control. Furthermore, we screened and identified potential anti-inflammatory constituents by ultra-performance liquid chromatography/quadrupole time-of-flight mass spectrometry (UPLC/Q-TOF-MS) combined with NF-κB activity luciferase reporter assay systems. Further cytokine detection confirmed the anti-inflammatory effects of the potential NF-κB inhibitors from YQFM.

RESULTS

The administration of YQFM significantly improved cardiac function and ameliorated the activity level of inflammatory mediators (such as tumor necrosis factor-alpha, interleukin-6, and interleukin-1β) in CHF rats. Eight potential anti-inflammatory ingredients, ginsenosides Rb1, Rg1, Rf, Rh1, Rc, Rb2, Ro, and Rg3, were characterized and confirmed. Among these compounds, ginsenoside Ro was revealed as a new NF-κB inhibitor.

CONCLUSION

The results suggested that NF-κB inactivation and cytokine suppression might be one of the main mechanisms of YQFM that caused ameliorative effects in CHF rats, and the major constituents of ginsenosides were identified playing a key role in the treatment of CHF.

Effects of early, late, and long-term nonselective β-blockade on left ventricular remodeling, function, and survival in chronic organic mitral regurgitation

BACKGROUND

Mitral regurgitation (MR) produces sympathetic nervous system activation which is detrimental in other causes of heart failure. However, whether β-blockade is beneficial in MR has not been determined.

METHODS AND RESULTS

Eighty-seven rats with significant organic MR were randomized to the β-blockade group (n=43) or the control group (n=44). Carvedilol was started in week 2 post MR induction and given for 23 to 35 weeks in the β-blockade group. Echocardiography was performed at baseline and at weeks 2, 6, 12, 24, 30, and 36 after MR induction. After 23 weeks of β-blockade, heart rates were significantly reduced by carvedilol (308 ± 25 versus 351 ± 31 beats per minute; P<0.001). Left ventricular end-diastolic (2.2 ± 0.7 versus 1.59 ± 0.6 mL; P<0.001), end-systolic volumes (0.72 ± 0.42 versus 0.40 ± 0.19 mL; P<0.001), and mass index (2.40 ± 0.55 versus 2.06 ± 0.62 g/kg; P<0.001) were significantly higher, and left ventricular fraction shortening (33 ± 7% versus 38 ± 7%; P<0.001) and ejection fraction (69 ± 11% versus 75 ± 7%; P<0.001) were significantly lower in the β-blockade group than in the control group. Systolic blood pressure was lower in the β-blockade group than in the control group (114 ± 10 versus 93 ± 12 mm Hg; P<0.005). Survival probability was significantly lower in the early β-blockade group than in the control group (88% versus 96%; P=0.03).

CONCLUSIONS

Early and long-term nonselective β-blockade was associated with adverse left ventricular remodeling, systolic dysfunction, and a reduction in survival in the experimental rat model of organic MR.

Transcriptional and post-transcriptional regulation of cGMP-dependent protein kinase (PKG-I): pathophysiological significance

The ability of the endothelium to produce nitric oxide, which induces generation of cyclic guanosine monophosphate (cGMP) that activates cGMP-dependent protein kinase (PKG-I), in vascular smooth muscle cells (VSMCs), is essential for the maintenance of vascular homeostasis. Yet, disturbance of this nitric oxide/cGMP/PKG-I pathway has been shown to play an important role in many cardiovascular diseases. In the last two decades, in vitro and in vivo models of vascular injury have shown that PKG-I is suppressed following nitric oxide, cGMP, cytokine, and growth factor stimulation. The molecular basis for these changes in PKG-I expression is still poorly understood, and they are likely to be mediated by a number of processes, including changes in gene transcription, mRNA stability, protein synthesis, or protein degradation. Emerging studies have begun to define mechanisms responsible for changes in PKG-I expression and have identified cis- and trans-acting regulatory elements, with a plausible role being attributed to post-translational control of PKG-I protein levels. This review will focus mainly on recent advances in understanding of the regulation of PKG-I expression in VSMCs, with an emphasis on the physiological and pathological significance of PKG-I down-regulation in VSMCs in certain circumstances.

Calcium-alginate hydrogel-encapsulated fibroblasts provide sustained release of vascular endothelial growth factor

Vascularization of engineered or damaged tissues is essential to maintain cell viability and proper tissue function. Revascularization of the left ventricle (LV) of the heart after myocardial infarction is particularly important, since hypoxia can give rise to chronic heart failure due to inappropriate remodeling of the LV after death of cardiomyocytes (CMs). Fibroblasts can express vascular endothelial growth factor (VEGF), which plays a major role in angiogenesis and also acts as a chemoattractant and survival factor for CMs and cardiac progenitors. In this in vitro model study, mouse NIH 3T3 fibroblasts encapsulated in 2% w/v Ca-alginate were shown to remain viable for 150 days. Semiquantitative reverse transcription-polymerase chain reaction and immunohistochemistry demonstrated that over 21 days of encapsulation, fibroblasts continued to express VEGF, while enzyme-linked immunosorbent assay showed that there was sustained release of VEGF from the Ca-alginate during this period. The scaffold degraded gradually over the 21 days, without reduction in volume. Cells released from the Ca-alginate at 7 and 21 days as a result of scaffold degradation were shown to retain viability, to adhere to fibronectin in a normal manner, and continue to express VEGF, demonstrating their potential to further contribute to maintenance of cardiac function after scaffold degradation. This model in vitro study therefore demonstrates that fibroblasts encapsulated in Ca-alginate provide sustained release of VEGF.

Quantitative magnetic resonance imaging can distinguish remodeling mechanisms after acute myocardial infarction based on the severity of ischemic insult

The type and extent of myocardial infarction encountered clinically is primarily determined by the severity of the initial ischemic insult. The purpose of the study was to differentiate longitudinal fluctuations in remodeling mechanisms in porcine myocardium following different ischemic insult durations. Animals (N = 8) were subjected to coronary balloon occlusion for either 90 or 45 min, followed by reperfusion. Imaging was performed on a 3 T MRI scanner between day-2 and week-6 postinfarction with edema quantified by T2, hemorrhage by T2*, vasodilatory function by blood-oxygenation-level-dependent T2 alterations and infarction/microvascular obstruction by contrast-enhanced imaging. The 90-min model produced large transmural infarcts with hemorrhage and microvascular obstruction, while the 45 min produced small nontransmural and nonhemorrhagic infarction. In the 90-min group, elevation of end-diastolic-volume, reduced cardiac function, persistence of edema, and prolonged vasodilatory dysfunction were all indicative of adverse remodeling; in contrast, the 45-min group showed no signs of adverse remodeling. The 45- and 90-min porcine models seem to be ideal for representing the low- and high-risk patient groups, respectively, commonly encountered in the clinic. Such in vivo characterization will be a key in predicting functional recovery and may potentially allow evaluation of novel therapies targeted to alleviate ischemic injury and prevent microvascular obstruction/hemorrhage.

Melanocortins and the cholinergic anti-inflammatory pathway

Experimental evidence indicates that small concentrations of inflammatory molecules produced by damaged tissues activate afferent signals through ascending vagus nerve fibers, that act as the sensory arm of an "inflammatory reflex". The subsequent activation of vagal efferent fibers, which represent the motor arm of the inflammatory reflex, rapidly leads to acetylcholine release in organs of the reticuloendothelial system. Acetylcholine interacts with α7 subunit-containing nicotinic receptors in tissue macrophages and other immune cells and rapidly inhibits the synthesis/release of tumor necrosis factor-α and other inflammatory cytokines. This neural anti-inflammatory response called "cholinergic anti-inflammatory pathway" is fast and integrated through the central nervous system. Preclinical studies are in progress, with the aim to develop therapeutic agents able to activate the cholinergic anti-inflammatory pathway. Melanocortin peptides bearing the adrenocorticotropin/α-melanocyte-stimulating hormone sequences exert a protective and life-saving effect in animals and humans in conditions of circulatory shock. These neuropeptides are likewise protective in other severe hypoxic conditions, such as prolonged respiratory arrest, myocardial ischemia, renal ischemia and ischemic stroke, as well as in experimental heart transplantation. Moreover, experimental evidence indicates that melanocortins reverse circulatory shock, prevent myocardial ischemia/reperfusion damage and exert neuroprotection against ischemic stroke through activation of the cholinergic anti-inflammatory pathway. This action occurs via stimulation of brain melanocortin MC3/MC4 receptors. Investigations that determine the molecular mechanisms of the cholinergic anti-inflammatory pathway activation could help design of superselective activators of this pathway.

Triterpenoid dihydro-CDDO-trifluoroethyl amide protects against maladaptive cardiac remodeling and dysfunction in mice: a critical role of Nrf2

BACKGROUND AND AIMS

Nuclear factor E2-related factor 2 (Nrf2) appears to be an attractive therapeutic target for the treatment of cardiac disease. We investigated whether a synthetic triterpenoid derivative of dihydro-CDDO-trifluoroethylamide (dh404), a novel Nrf2 activator, protects against pathological cardiac responses to hemodynamic stress in mice.

METHODS

Cardiac maladaptive remodeling and dysfunction were established by transverse aortic constriction (TAC) in mice. Hypertrophic growth of rat neonatal cardiomyocytes was induced by angiotensin II (Ang II). Cell death of rat neonatal cardiomyocytes was induced with hydrogen peroxide (H₂O₂). Cellular proliferation of rat neonatal cardiac fibroblasts was induced by Ang II, norepinephrine (NE) and phenylephrine (PE). Protein expression was assessed by immunochemical staining and Western blots. Gene expression was determined by real time reverse transcription-polymerase chain reaction (Q-PCR).

RESULTS

TAC suppressed myocardial Nrf2 expression, increased myocardial 4-hydroxy-2-nonenal and 8-hydroxydeoxyguanosine levels, and induced cardiac hypertrophy, fibrosis and apoptosis, and overt heart failure and death in mice. Administration of dh404 inhibited the pathological cardiac remodeling and dysfunction, and reduced the mortality. Moreover, dhd404 elevated myocardial levels of Nrf2 and Nrf2 nuclear translocation with a dramatic suppression of the oxidative stress in the heart. Dh404 inhibited hypertrophic growth and death in primary culture of rat neonatal cardiomyocytes and suppressed proliferation in primary culture of rat neonatal cardiac fibroblasts. However, these effects of dh404 were blunted by knocking down of Nrf2.

CONCLUSION

These findings demonstrate that dh404 prevents pathological cardiac remodeling and dysfunction by activating Nrf2, indicating a therapeutic potential of dh404 for cardiac disease.

Remodeling after acute myocardial infarction: mapping ventricular dilatation using three dimensional CMR image registration

BACKGROUND

Progressive heart failure due to remodeling is a major cause of morbidity and mortality following myocardial infarction. Conventional clinical imaging measures global volume changes, and currently there is no means of assessing regional myocardial dilatation in relation to ischemic burden. Here we use 3D co-registration of Cardiovascular Magnetic Resonance (CMR) images to assess the long-term effects of ischemia-reperfusion injury on left ventricular structure after acute ST-elevation myocardial infarction (STEMI).

METHODS

Forty six patients (age range 33-77 years) underwent CMR imaging within 7 days following primary percutaneous coronary intervention (PPCI) for acute STEMI with follow-up at one year. Functional cine imaging and Late Gadolinium Enhancement (LGE) were segmented and co-registered. Local left ventricular wall dilatation was assessed by using intensity-based similarities to track the structural changes in the heart between baseline and follow-up. Results are expressed as means, standard errors and 95% confidence interval (CI) of the difference.

RESULTS

Local left ventricular remodeling within infarcted myocardium was greater than in non-infarcted myocardium (1.6%±1.0 vs 0.3%±0.9, 95% CI: -2.4% - -0.2%, P=0.02). One-way ANOVA revealed that transmural infarct thickness had a significant effect on the degree of local remodeling at one year (P<0.0001) with greatest wall dilatation observed when infarct transmurality exceeded 50%. Infarct remodeling was more severe when microvascular obstruction (MVO) was present (3.8%±1.3 vs -1.6%±1.4, 95% CI: -9.1% - -1.5%, P=0.007) and when end-diastolic volume had increased by >20% (4.8%±1.4 vs -0.15%±1.2, 95% CI: -8.9% - -0.9%, P=0.017).

CONCLUSIONS

The severity of ischemic injury has a significant effect on local ventricular wall remodeling with only modest dilatation observed within non-ischemic myocardium. Limitation of chronic remodeling may therefore depend on therapies directed at modulating ischemia-reperfusion injury. CMR co-registration has potential for assessing dynamic changes in ventricular structure in relation to therapeutic interventions.

Melanocortins as potential therapeutic agents in severe hypoxic conditions

Melanocortin peptides with the adrenocorticotropin/melanocyte-stimulating hormone (ACTH/MSH) sequences and synthetic analogs have protective and life-saving effects in experimental conditions of circulatory shock, myocardial ischemia, ischemic stroke, traumatic brain injury, respiratory arrest, renal ischemia, intestinal ischemia and testicular ischemia, as well as in experimental heart transplantation. Moreover, melanocortins improve functional recovery and stimulate neurogenesis in experimental models of cerebral ischemia. These beneficial effects of ACTH/MSH-like peptides are mostly mediated by brain melanocortin MC(3)/MC(4) receptors, whose activation triggers protective pathways that counteract the main ischemia/reperfusion-related mechanisms of damage. Induction of signaling pathways and other molecular regulators of neural stem/progenitor cell proliferation, differentiation and integration seems to be the key mechanism of neurogenesis stimulation. Synthesis of stable and highly selective agonists at MC(3) and MC(4) receptors could provide the potential for development of a new class of drugs for a novel approach to management of severe ischemic diseases.

Novel therapeutic approaches to post-infarction remodelling

Adverse cardiac remodelling is a major cause of morbidity and mortality following acute myocardial infarction (MI). Mechanical and neurohumoral factors involved in structural and molecular post-infarction remodelling were important targets in research and treatment for years. More recently, therapeutic strategies that address myocardial regeneration and pathophysiological mechanisms of infarct wound healing appear to be useful novel tools to prevent progressive ventricular dilation, functional deterioration, life-threatening arrhythmia, and heart failure. This review provides an overview of future and emerging therapies for cardiac wound healing and remodelling after MI.

Impact of diabetes on postinfarction heart failure and left ventricular remodeling

Diabetes mellitus, the metabolic syndrome, and the underlying insulin resistance are increasingly associated with diastolic dysfunction and reduced stress tolerance. The poor prognosis associated with heart failure in patients with diabetes after myocardial infarction is likely attributable to many factors, important among which is the metabolic impact from insulin resistance and hyperglycemia on the regulation of microvascular perfusion and energy generation in the cardiac myocyte. This review summarizes epidemiologic, pathophysiologic, diagnostic, and therapeutic data related to diabetes and heart failure in acute myocardial infarction and discusses novel perceptions and strategies that hold promise for the future and deserve further investigation.