Adverse Remodeling and Reverse Remodeling After Myocardial Infarction

Functionalised peptide hydrogel for the delivery of cardiac progenitor cells

Heart failure (HF) remains one of the leading causes of death worldwide; most commonly developing after myocardial infarction (MI). Since adult cardiomyocytes characteristically do not proliferate, cells lost during MI are not replaced. As a result, the heart has a limited regenerative capacity. There is, therefore, a need to develop novel cell-based therapies to promote the regeneration of the heart after MI. The delivery and retention of cells at the injury site remains a significant challenge. In this context, we explored the potential of using an injectable, RGDSP-functionalised self-assembling peptide - FEFEFKFK - hydrogel as scaffold for the delivery and retention of rat cardiac progenitor cells (CPCs) into the heart. Our results show that culturing CPCs in vitro within the hydrogel for one-week promoted their spontaneous differentiation towards adult cardiac phenotypes. Injection of the hydrogel on its own, or loaded with CPCs, into the rat after injury resulted in a significant reduction in myocardial damage and left ventricular dilation.

Empagliflozin and left ventricular diastolic function following an acute coronary syndrome in patients with type 2 diabetes

Sodium-glucose cotransporter 2 inhibitors can improve heart failure outcomes, however, the effects on left ventricular (LV) function remain unclear. This prospective observational study aimed to investigate whether initiating empagliflozin therapy was associated with improved LV diastolic function following an acute coronary syndrome (ACS) in patients with type 2 diabetes (T2D). Patients with ACS and T2D were identified during hospitalisation in a cardiology unit. Empagliflozin was initiated at discharge in eligible patients (i.e. HbA1c > 7%) without contraindications or precautions. Transthoracic echocardiography was performed during admission and after 3-6 months. Changes in echocardiographic parameters were compared between patients initiated on empagliflozin versus not initiated on empagliflozin (control). There were 22 patients in each group (n = 44). Baseline characteristics, medications and echocardiographic parameters were similar except HbA1c (empagliflozin: 9.8 ± 1.6% versus control: 6.6 ± 0.7%, p < 0.001). Baseline LV global longitudinal strain (GLS) (empagliflozin: - 12.4 ± 2.8 versus control: - 13.0 ± 3.6%) and ejection fraction (51.1 ± 11.3 versus 54.9 ± 10.8%) were similar. The difference in change from baseline to follow-up was significant for LV mass index (empagliflozin: - 14.1 ± 21.6 versus control: 3.6 ± 18.7 g/m², p = 0.006), left atrial volume index (- 2.1 ± 8.1 versus 3.4 ± 9.5 ml/m², p = 0.045), mitral valve E-wave velocity (- 0.14 ± 0.23 versus 0.03 ± 0.16 m/s, p = 0.007) and average E/e' (- 2.1 ± 2.6 versus 0.9 ± 3.4, p = 0.002). There were no significant between-group differences in change for LV GLS, ejection fraction and volume. In patients with ACS and T2D, addition of empagliflozin to ACS therapy at discharge was associated with a reduction in LV mass and favourable changes in diastolic function parameters. Further studies are warranted to investigate these findings.

Three-dimensional scaffold-free microtissues engineered for cardiac repair

Cardiovascular diseases, including myocardial infarction (MI), persist as the leading cause of mortality and morbidity worldwide. The limited regenerative capacity of the myocardium presents significant challenges specifically for the treatment of MI and, subsequently, heart failure (HF). Traditional therapeutic approaches mainly rely on limiting the induced damage or the stress on the remaining viable myocardium through pharmacological regulation of remodeling mechanisms, rather than replacement or regeneration of the injured tissue. The emerging alternative regenerative medicine-based approaches have focused on restoring the damaged myocardial tissue with newly engineered functional and bioinspired tissue units. Cardiac regenerative medicine approaches can be broadly categorized into three groups: cell-based therapies, scaffold-based cardiac tissue engineering, and scaffold-free cardiac tissue engineering. Despite significant advancements, however, the clinical translation of these approaches has been critically hindered by two key obstacles for successful structural and functional replacement of the damaged myocardium, namely: poor engraftment of engineered tissue into the damaged cardiac muscle and weak electromechanical coupling of transplanted cells with the native tissue. To that end, the integration of micro- and nanoscale technologies along with recent advancements in stem cell technologies have opened new avenues for engineering of structurally mature and highly functional scaffold-based (SB-CMTs) and scaffold-free cardiac microtissues (SF-CMTs) with enhanced cellular organization and electromechanical coupling for the treatment of MI and HF. In this review article, we will present the state-of-the-art approaches and recent advancements in the engineering of SF-CMTs for myocardial repair.

An inhibitor role of Nrf2 in the regulation of myocardial senescence and dysfunction after myocardial infarction

Cellular senescence, a process whereby cells enter a state of permanent growth arrest, appears to regulate cardiac pathological remodeling and dysfunction in response to various stresses including myocardial infarction (MI). However, the precise role as well as the underlying regulatory mechanism of cardiac cellular senescence in the ischemic heart disease remain to be further determined. Herein we report an inhibitory role of Nrf2, a key transcription factor of cellular defense, in regulating cardiac senescence in infarcted hearts as well as a therapeutic potential of targeting Nrf2-mediated suppression of cardiac senescence in the treatment of MI-induced cardiac dysfunction. MI was induced by left coronary artery ligation for 28 days in mice. Heart tissues from the infarct border zone were used for the analyses. The MI-induced cardiac dysfunction was associated with increased myocardial cell senescence, oxidative stress and apoptosis in adult wild type (WT) mice. In addition, a downregulated Nrf2 activity was associated with upregulated Keap1 levels and increased phosphorylation of JAK and FYN in the infarcted border zone heart tissues. Nrf2 Knockout (Nrf2^-/-) enhanced the MI-induced myocardial, cardiac dysfunction and senescence. Qiliqiangxin (QLQX), a herbal medicine which could reverse the MI-induced suppression of Nrf2 activity, significantly inhibited the MI-induced cardiac senescence, apoptosis, and cardiac dysfunction in WT mice but not in Nrf2^-/- mice. These results indicate that MI downregulates Nrf2 activity thus promoting oxidative stress to accelerate cellular senescence in the infarcted heart towards cardiac dysfunction and Nrf2 may be a drug target for suppressing the cellular senescence-associated pathologies in infarcted hearts.

Adverse Cardiac Remodelling after Acute Myocardial Infarction: Old and New Biomarkers

The prevalence of heart failure (HF) due to cardiac remodelling after acute myocardial infarction (AMI) does not decrease regardless of implementation of new technologies supporting opening culprit coronary artery and solving of ischemia-relating stenosis with primary percutaneous coronary intervention (PCI). Numerous studies have examined the diagnostic and prognostic potencies of circulating cardiac biomarkers in acute coronary syndrome/AMI and heart failure after AMI, and even fewer have depicted the utility of biomarkers in AMI patients undergoing primary PCI. Although complete revascularization at early period of acute coronary syndrome/AMI is an established factor for improved short-term and long-term prognosis and lowered risk of cardiovascular (CV) complications, late adverse cardiac remodelling may be a major risk factor for one-year mortality and postponded heart failure manifestation after PCI with subsequent blood flow resolving in culprit coronary artery. The aim of the review was to focus an attention on circulating biomarker as a promising tool to stratify AMI patients at high risk of poor cardiac recovery and developing HF after successful PCI. The main consideration affects biomarkers of inflammation, biomechanical myocardial stress, cardiac injury and necrosis, fibrosis, endothelial dysfunction, and vascular reparation. Clinical utilities and predictive modalities of natriuretic peptides, cardiac troponins, galectin 3, soluble suppressor tumorogenicity-2, high-sensitive C-reactive protein, growth differential factor-15, midregional proadrenomedullin, noncoding RNAs, and other biomarkers for adverse cardiac remodelling are discussed in the review.

Connexin 43 Deficiency Is Associated with Reduced Myocardial Scar Size and Attenuated TGFβ1 Signaling after Transient Coronary Occlusion in Conditional Knock-Out Mice

Previous studies demonstrated a reduction in myocardial scar size in heterozygous Cx43^+/- mice subjected to permanent coronary occlusion. However, patients presenting with ST segment elevation myocardial infarction often undergo rapid coronary revascularization leading to prompt restoration of coronary flow. Therefore, we aimed to assess changes in scar size and left ventricular remodeling following transient myocardial ischemia (45 min) followed by 14 days of reperfusion using Cx43^fl/fl (controls) and Cx43^Cre-ER(T)/fl inducible knock-out (Cx43 content: 50%) mice treated with vehicle or 4-hydroxytamoxifen (4-OHT) to induce a Cre-ER(T)-mediated global deletion of the Cx43 floxed allele. The scar area (picrosirius red), measured 14 days after transient coronary occlusion, was similarly reduced in both vehicle and 4-OHT-treated Cx43^Cre-ER(T)/fl mice, compared to Cx43^fl/fl animals, having normal Cx43 levels (15.78% ± 3.42% and 16.54% ± 2.31% vs. 25.40% ± 3.14% and 22.43% ± 3.88% in vehicle and 4-OHT-treated mice, respectively, p = 0.027). Left ventricular dilatation was significantly attenuated in both Cx43-deficient groups (p = 0.037 for left ventricular end-diastolic diameter). These protective effects were correlated with an attenuated enhancement in pro-transforming growth factor beta 1 (TGFβ1) expression after reperfusion. In conclusion, our data demonstrate that Cx43 deficiency induces a protective effect on scar formation after transient coronary occlusion in mice, an effect associated with reduced left ventricular remodeling and attenuated enhancement in pro-TGFβ1 expression.

Biomechanics of infarcted left Ventricle-A review of experiments

Myocardial infarction (MI) is one of leading diseases to contribute to annual death rate of 5% in the world. In the past decades, significant work has been devoted to this subject. Biomechanics of infarcted left ventricle (LV) is associated with MI diagnosis, understanding of remodelling, MI micro-structure and biomechanical property characterizations as well as MI therapy design and optimization, but the subject has not been reviewed presently. In the article, biomechanics of infarcted LV was reviewed in terms of experiments achieved in the subject so far. The concerned content includes experimental remodelling, kinematics and kinetics of infarcted LVs. A few important issues were discussed and several essential topics that need to be investigated further were summarized. Microstructure of MI tissue should be observed even carefully and compared between different methods for producing MI scar in the same animal model, and eventually correlated to passive biomechanical property by establishing innovative constitutive laws. More uniaxial or biaxial tensile tests are desirable on MI, border and remote tissues, and viscoelastic property identification should be performed in various time scales. Active contraction experiments on LV wall with MI should be conducted to clarify impaired LV pumping function and supply necessary data to the function modelling. Pressure-volume curves of LV with MI during diastole and systole for the human are also desirable to propose and validate constitutive laws for LV walls with MI.

The apelinergic system: a perspective on challenges and opportunities in cardiovascular and metabolic disorders

The apelinergic pathway has been generating increasing interest in the past few years for its potential as a therapeutic target in several conditions associated with the cardiovascular and metabolic systems. Indeed, preclinical and, more recently, clinical evidence both point to this G protein-coupled receptor as a target of interest in the treatment of not only cardiovascular disorders such as heart failure, pulmonary arterial hypertension, atherosclerosis, or septic shock, but also of additional conditions such as water retention/hyponatremic disorders, type 2 diabetes, and preeclampsia. While it is a peculiar system with its two classes of endogenous ligand, the apelins and Elabela, its intricacies are a matter of continuing investigation to finely pinpoint its potential and how it enables crosstalk between the vasculature and organ systems of interest. In this perspective article, we first review the current knowledge on the role of the apelinergic pathway in the above systems, as well as the associated therapeutic indications and existing pharmacological tools. We also offer a perspective on the challenges and potential ahead to advance the apelinergic system as a target for therapeutic intervention in several key areas.

Clinical Studies of Cell Therapy in Cardiovascular Medicine: Recent Developments and Future Directions

Given the rising prevalence of cardiovascular disease worldwide and the limited therapeutic options for severe heart failure, novel technologies that harness the regenerative capacity of the heart are sorely needed. The therapeutic use of stem cells has the potential to reverse myocardial injury and improve cardiac function, in contrast to most current medical therapies that only mitigate heart failure symptoms. Nearly 2 decades and >200 trials for cardiovascular disease have revealed that most cell types are safe; however, their efficacy remains controversial, limiting the transition of this therapy from investigation to practice. Lessons learned from these initial studies are driving the design of new clinical trials; higher fidelity of cell isolation techniques, standardization of conditions, more consistent use of state of the art measurement techniques, and assessment of multiple end points to garner insights into the efficacy of stem cells. Translation to clinical trials has almost outpaced our mechanistic understanding, and individual patient factors likely play a large role in stem cell efficacy. Therefore, careful analysis of dosing, delivery methods, and the ideal patient populations is necessary to translate cell therapy from research to practice. We are at a pivotal stage in the field in which information from many relatively small clinical trials must guide carefully executed efficacy trials. Larger efficacy trials are being launched to answer questions about older, first-generation stem cell therapeutics, while novel, second-generation products are being introduced into the clinical realm. This review critically examines the current state of clinical research on cell-based therapies for cardiovascular disease, highlighting the controversies in the field, improvements in clinical trial design, and the application of exciting new cell products.

Genetic profiling of fatty acid desaturase polymorphisms identifies patients who may benefit from high-dose omega-3 fatty acids in cardiac remodeling after acute myocardial infarction-Post-hoc analysis from the OMEGA-REMODEL randomized controlled trial

Background

The double-blind OMEGA-REMODEL placebo-controlled randomized trial of high-dose omega-3 fatty acids (O-3FA) post-acute myocardial infarction (AMI) reported improved cardiac remodeling and attenuation of non-infarct myocardial fibrosis. Fatty acid desaturase 2 (FADS2) gene cluster encodes key enzymes in the conversion of essential omega-3 and omega-6 fatty acids into active arachidonic (ArA) and eicosapentaenoic acids (EPA), which influence cardiovascular outcomes.

Methods and results

We tested the hypothesis that the genotypic status of FADS2 (rs1535) modifies therapeutic response of O-3FA in post-AMI cardiac remodeling in 312 patients. Consistent with known genetic polymorphism of FADS2, patients in our cohort with the guanine-guanine (GG) genotype had the lowest FADS2 activity assessed by arachidonic acid/linoleic acid (ArA/LA) ratio, compared with patients with the adenine-adenine (AA) and adenine-guanine (AG) genotypes (GG:1.62±0.35 vs. AA: 2.01±0.36, p<0.0001; vs. AG: 1.76±0.35, p = 0.03). When randomized to 6-months of O-3FA treatment, GG patients demonstrated significant lowering of LV end-systolic volume index (LVESVi), N-terminal prohormone of brain natriuretic peptide (NT-proBNP), and galectin-3 levels compared to placebo (-4.4 vs. 1.2 ml/m², -733 vs. -181 pg/mL, and -2.0 vs. 0.5 ng/mL; p = 0.006, 0.006, and 0.03, respectively). In contrast, patients with either AA or AG genotype did not demonstrate significant lowering of LVESVi, NT-proBNP, or galectin-3 levels from O-3FA treatment, compared to placebo. The odds ratios for improving LVESVi by 10% with O-3FA treatment was 7.2, 1.6, and 1.2 in patients with GG, AG, and AA genotypes, respectively.

Conclusion

Genetic profiling using FADS2 genotype can predict the therapeutic benefits of O-3FA treatment against adverse cardiac remodeling during the convalescent phase of AMI.

Clinical trial registration information

clinicaltrials.gov Identifier: NCT00729430.

[Indicators of the left ventricular-arterial coupling interaction in chronic forms of ischemic heart disease: relationships of the protradenomedullin and N-terminal probrain natriuretic peptide]

PURPOSE OF THE STUDY

Analyze the parameters of the interaction between the left ventricle and the arterial system in patients with chronic forms of coronary heart disease and to identify relationships with levels of proadrenomedullin (MR‑proADM) and N‑terminal precursor of the brain natriuretic peptide B (NT‑proBNP).

MATERIALS AND METHODS

240 patients with chronic forms of coronary heart disease (median - 55,9 [43; 63] years) and Q‑forming myocardial infarction in the past were examined. Of these, 110 patients with myocardial infarction and preserved lef ventricular ejection fraction and 130 patients with ischemic cardiomyopathy. All patients were calculated parameters of lef ventricular‑arterial interaction and the determination in blood serum levels of MR‑proADM and NT‑proBNP.

RESULTS

In patients with ischemic cardiomyopathy, an increase in the lef ventricular‑arterial interaction index was detected (2,51 [1,18; 5,00]), which reflects a decrease in the functional abilities and efficiency of the heart. In patients with myocardial infarction and a preserved left ventricular ejection fraction, this indicator was in the range of normal values (0,78 [0,55; 1,07]), which indicates an effective cardiac work. A study of MR‑proADM and NT‑proBNP levels demonstrated an increase in both groups (1,72 [1,56; 1,98] nmol/l and 779,3 [473; 2193] pg/ml in the group of patients with ischemic cardiomyopathy; 0,89 [0,51; 1,35] nmol/l and 246 [118; 430] pg/ml in the group of patients with myocardial infarction and preserved left ventricular ejection fraction), and the correlation analysis with left ventricular‑arterial coupling interaction parameters allowed identify statistically significant connections (in the group of patients with ischemic cardiomyopathy: with the level of MR‑proADM ‑ r=0,67, p=0,006, with the level of NT‑proBNP ‑ r=0,78, p&lt;0,001; in the group of patients with myocardial infarction and preserved left ventricular ejection fraction: with MR‑proADM level ‑ r=‑0,52, p=0,024, with NT‑proBNP level ‑ r =‑0,38, p=0,037).

CONCLUSION

The findings suggest a pathogenetic association between the biomarkers under study and the parameters of left ventricular‑arterial coupling interaction.

Effects of the Angiotensin-Receptor Neprilysin Inhibitor on Cardiac Reverse Remodeling: Meta-Analysis

Background The angiotensin-receptor neprilysin inhibitor (ARNI) sacubitril/valsartan was shown to be superior to the angiotensin-converting enzyme inhibitor enalapril in terms of reducing cardiovascular mortality in the PARADIGM-HF (Prospective Comparison of ARNI with angiotensin-converting enzyme inhibitor to Determine Impact on Global Mortality and Morbidity in Heart Failure) study. However, the impact of ARNI on cardiac reverse remodeling (CRR) has not been established. Methods and Results We conducted a meta-analysis to compare the effects of ARNI versus angiotensin-converting enzyme inhibitors or angiotensin receptor blockers on CRR indices. We searched databases for studies published between 2010 and 2019 that reported CRR indices following ARNI administration. Effect size was expressed as mean difference (MD) with 95% CIs. Twenty studies enrolling 10 175 patients were included. ARNI improved functional capacity in patients with heart failure (HF) and a reduced ejection fraction (EF), including increasing New York Heart Association functional class (MD -0.79, 95% CI -0.86, -0.71) and 6-minute walking distance (MD 27.62 m, 95% CI 15.76, 39.48). ARNI outperformed angiotensin-converting enzyme inhibitors/angiotensin receptor blockers in terms of CRR indices, with striking changes in left ventricular EF, diameter, and volume. However, there were no significant improvements in indices except left ventricular mass index (MD -3.25 g/m2, 95% CI -3.78, -2.72) and left atrial volume (MD -7.20 mL, 95% CI -14.11, -0.29) in HF patients with preserved EF treated with ARNI. Improvements in CRR indices were observed at 3 months and became more significant with longer follow-up to 12 months. The regression equation for the relationship between left ventricular EF and end-diastolic dimension was y=0.041+0.071x+0.045x2+0.006x3. Conclusions ARNI distinctly improved left ventricular size and hypertrophy compared with angiotensin-converting enzyme inhibitors/angiotensin receptor blockers in HF with reduced EF patients, even after short-term follow-up. Patients appeared to benefit more in terms of CRR treated with ARNI as early as possible and for at least 3 months. Further large sample trials are required to determine the effects of ARNI on CRR in HF with preserved EF patients.

Sodium tanshinone IIA sulfonate prevents the adverse left ventricular remodelling: Focus on polymorphonuclear neutrophil-derived granule components

AIMS

The aims of this study were to evaluate the effects of sodium tanshinone IIA sulfonate (STS) on left ventricular (LV) remodelling after for ST-elevated myocardial infarction (STEMI).

METHODS AND RESULTS

In this prospective, randomized clinical trial, 101 patients with the ST-elevated MI (STEMI) and a successful reperfusion were immediately randomized to receive STS (80 mg qd for 7 days) or saline control, along with standard therapy. The primary effectiveness endpoint is the % change in LV end diastolic volumes index (%∆ LVEDVi) as measured by echocardiography from baseline to 6 months. Secondary effectiveness endpoints include 6-month period for major adverse cardiac events (MACE), including the occurrence of recurrent myocardial infarction, death, hospitalization for heart failure and malignant arrhythmia. The 6-month changes in %∆ LVEDVi were significantly smaller in the STS group than in the control group [-5.05% vs 3.32%; P < 0.001]. With respect to MACE, there was a significant difference between those who received STS (8.16%) and those patients on control (26.00%) (P = 0.019). Meaningfully, results of parallel tests aimed at mechanistic explanation of the reported clinical effects, revealed a significantly reduced levels of neutrophils-derived granule components in the blood of STS treated patients.

CONCLUSION

We found that short-term treatment with STS reduced progressive left ventricular remodelling and subsequent better clinical outcome that could be mechanistically linked to the inhibition of the ultimate damage of infarcted myocardium by infiltrating neutrophils.

Different adaptive NO-dependent Mechanisms in Normal and Hypertensive Conditions

Myocardial infarction (MI) remains the leading cause of death worldwide. We aimed to investigate the effect of NO deficiency on selective biochemical parameters within discreet myocardial zones after experimentally induced MI. To induce MI, the left descending coronary artery was ligated in two groups of 16-week-old WKY rats. In one group, NO production was inhibited by L-NAME (20 mg/kg/day) administration four weeks prior to ligation. Sham operations were performed on both groups as a control. Seven days after MI, we evaluated levels of nitric oxide synthase (NOS) activity, eNOS, iNOS, NFҡB/p65 and Nrf2 in ischemic, injured and non-ischemic zones of the heart. Levels of circulating TNF-α and IL-6 were evaluated in the plasma. MI led to increased NOS activity in all investigated zones of myocardium as well as circulating levels of TNF-α and IL-6. L-NAME treatment decreased NOS activity in the heart of sham operated animals. eNOS expression was increased in the injured zone and this could be a compensatory mechanism that improves the perfusion of the myocardium and cardiac dysfunction. Conversely, iNOS expression increased in the infarcted zone and may contribute to the inflammatory process and irreversible necrotic changes.

Prognostic Impact of β-Blocker Dose After Acute Myocardial Infarction

BACKGROUND

The differential prognostic impact of β-blocker dose after acute myocardial infarction (AMI) has been under debate. The current study sought to compare clinical outcome after AMI according to β-blocker dose using the Korea Acute Myocardial Infarction Registry-National Institutes of Health (KAMIR-NIH). Methods and Results: Of the total population of 13,104 consecutive AMI patients enrolled in the KAMIR-NIH, the current study analyzed 11,909 patients. These patients were classified into 3 groups (no β-blocker; low-dose [<25% of target dose]; and high-dose [≥25% of target dose]). The primary outcome was cardiac death at 1 year. Compared with the no β-blocker group, both the low-dose and high-dose groups had significantly lower risk of cardiac death (HR, 0.435; 95% CI: 0.363-0.521, P<0.001; HR, 0.519; 95% CI: 0.350-0.772, P=0.001, respectively). The risk of cardiac death, however, was similar between the high- and low-dose groups (HR, 1.194; 95% CI: 0.789-1.808, P=0.402). On multivariable adjustment and inverse probability weighted analysis, the result was the same.

CONCLUSIONS

The use of β-blockers in post-AMI patients had significant survival benefit compared with no use of β-blockers. There was no significant additional benefit of high-dose β-blockers compared with low-dose β-blockers, however, in terms of 1-year risk of cardiac death.

Left ventricular restoration devices post myocardial infarction

Even in the era of percutaneous reperfusion therapy, left ventricular (LV) remodeling after myocardial infarction (MI) leading to heart failure remains a major health concern. Contractile dysfunction of the infarcted myocardium results in an increased pressure load, leading to maladaptive reshaping of the LV. Several percutaneous transcatheter procedures have been developed to deliver devices that restore LV shape and function. The purposes of this review are to discuss the spectrum of transcatheter devices that are available or in development for attenuation of adverse LV remodeling and to critically examine the available evidence for improvement of functional status and cardiovascular outcomes.

Improvements in long standing cardiac pathologies by individualized homeopathic remedies: A case series

We present three cases of cardiac arrest at different stages of pathology. Acute myocardial infarction and resulting heart failure is emerging as the leading cause of mortality. In the long run, acute episodes and cardiac remodelling can cause considerable damage and result in heart failure. In these cases, individualized homeopathic therapy was instituted along with the conventional medicines and the results were encouraging. The changes in the laboratory diagnostic parameters (single-photon emission computed tomography, electrocardiograph, echocardiography and ejection fraction as the case may be) are demonstrated over time. The key result seen in all three cases was the preservation of general well-being while the haemodynamic states also improved. While the three cases provide evidence of positive outcomes for homeopathic therapy, more extensive studies are required in a hospital setting to establish the real extent to which this therapy may be employed.

Follistatin-like 1 in development and human diseases

Follistatin-like 1 (FSTL1) is a secreted glycoprotein displaying expression changes during development and disease, among which cardiovascular disease, cancer, and arthritis. The cardioprotective role of FSTL1 has been intensively studied over the last years, though its mechanism of action remains elusive. FSTL1 is involved in multiple signaling pathways and biological processes, including vascularization and regulation of the immune response, a feature that complicates its study. Binding to the DIP2A, TLR4 and BMP receptors have been shown, but other molecular partners probably exist. During cancer progression and rheumatoid arthritis, controversial data have been reported with respect to the proliferative, apoptotic, migratory, and inflammatory effects of FSTL1. This controversy might reside in the extensive post-transcriptional regulation of FSTL1. The FSTL1 primary transcript also encodes for a microRNA (miR-198) in primates and multiple microRNA-binding sites are present in the 3'UTR. The switch between expression of the FSTL1 protein and miR-198 is an important regulator of tumour metastasis and wound healing. The glycosylation state of FSTL1 is a determinant of biological activity, in cardiomyocytes the glycosylated form promoting proliferation and the non-glycosylated working anti-apoptotic. Moreover, the glycosylation state shows differences between species and tissues which might underlie the differences observed in in vitro studies. Finally, regulation at the level of protein secretion has been described.

Summed thickening score by myocardial perfusion imaging: A risk factor of left ventricular remodeling in patients with myocardial infarction

BACKGROUND

Left ventricular (LV) remodeling has adverse effects on the prognosis of patients with myocardial infarction (MI). The aim of this study is to identify the risk factors of LV remodeling in MI patients by radionuclide myocardial imaging.

METHODS AND RESULTS

This retrospective study consisted of 92 patients who had a history of definite prior MI on ECG and underwent both resting gated single photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) and positron emission tomography (PET) myocardial metabolism imaging. LV remodeling was defined as > mean + 2SD of LV end-diastolic volume index (LVEDVi) in the normal database. LV enlargement, cardiac dysfunction, wall thickening abnormalities expressed as summed thickening score (STS) were more severe in the old MI patients as compared to those with subacute MI. STS (Odds ratio, 1.296; P = .004) and the proportion of segments with reduced wall thickening in segments with normal perfusion (Odds ratio, 1.110; P = .001) were identified as the independent factors of LV remodeling in subacute and old MI patients in the multivariate binary regression model. Total perfusion deficit (TPD), viable myocardium, scar, and the proportion of segments with reduced wall thickening in segments with decreased perfusion showed strong correlation with LV remodeling in the univariate regression model as well.

CONCLUSIONS

LV remodeling in old MI patients is more extensive and severe than that in subacute MI patients. LV wall thickening abnormalities as expressed by STS and the proportion of segments with reduced wall thickening in segments with normal perfusion are the independent risk factors of LV remodeling in MI patients.

Tongguan Capsule Mitigates Post-myocardial Infarction Remodeling by Promoting Autophagy and Inhibiting Apoptosis: Role of Sirt1

Left ventricular (LV) adverse remodeling and the concomitant functional deterioration contributes to the poor prognosis of patients with myocardial infarction (MI). Thus, a more effective treatment strategy is needed. Tongguan capsule (TGC), a patented Chinese medicine, has been shown to be cardioprotective in both humans and animals following ischemic injury, although its precise mechanism remains unclear. To investigate whether TGC can improve cardiac remodeling in the post-infarct heart, adult C57/BL6 mice underwent coronary artery ligation and were administered TGC or vehicle (saline) for 6 weeks. The results demonstrated that the TGC group showed significant improvement in survival ratio and cardiac function and structure as compared to the vehicle group. Histological and western blot analyses revealed decreased cellular inflammation and apoptosis in cardiomyocytes of the TGC group. Furthermore, TGC upregulated the Atg5 expression and LC3II-to-LC3I ratio but downregulated autophagy adaptor p62 expression, suggesting that TGC led to increased autophagic flux. Interestingly, with the administration of 3-methyladenine, an autophagy inhibitor, in conjunction with TGC, the aforesaid effects significantly decreased. Further mechanistic studies revealed that TGC increased silent information regulator 1 (Sirt1) expression to reduce the phosphorylation of the mammalian target of rapamycin and its downstream effectors P70S6K and 4EBP1. Moreover, the induction of Sirt1 by TGC was inhibited by the specific inhibitor EX527. In the presence of EX527, TGC-induced autophagy-specific proteins were downregulated, while apoptotic and inflammatory factors were upregulated. In summary, our results demonstrate that TGC improved cardiac remodeling in a murine model of MI by preventing cardiomyocyte inflammation and apoptosis but enhancing autophagy through Sirt1 activation.

Heart Disease and Relaxin: New Actions for an Old Hormone

The hormone relaxin has long been recognized for its involvement in maternal adaptation during pregnancy. However, discoveries during the past two decades on the mechanism of action of relaxin, its family of receptors, and newly described roles in attenuating ischemia/reperfusion (I/R) injury, inflammation, and arrhythmias have prompted vast interest in exploring its therapeutic potential in cardiovascular disease. These observations inspired recently concluded clinical trials in patients with acute heart failure. This review discusses our current understanding of the protective signaling pathways elicited by relaxin in the heart, and highlights important new breakthroughs about relaxin signaling that may pave the way to more carefully designed future trials.

Cardiac Actions of a Small Molecule Inhibitor Targeting GATA4-NKX2-5 Interaction

Transcription factors are fundamental regulators of gene transcription, and many diseases, such as heart diseases, are associated with deregulation of transcriptional networks. In the adult heart, zinc-finger transcription factor GATA4 is a critical regulator of cardiac repair and remodelling. Previous studies also suggest that NKX2-5 plays function role as a cofactor of GATA4. We have recently reported the identification of small molecules that either inhibit or enhance the GATA4–NKX2-5 transcriptional synergy. Here, we examined the cardiac actions of a potent inhibitor (3i-1000) of GATA4–NKX2-5 interaction in experimental models of myocardial ischemic injury and pressure overload. In mice after myocardial infarction, 3i-1000 significantly improved left ventricular ejection fraction and fractional shortening, and attenuated myocardial structural changes. The compound also improved cardiac function in an experimental model of angiotensin II -mediated hypertension in rats. Furthermore, the up-regulation of cardiac gene expression induced by myocardial infarction and ischemia reduced with treatment of 3i-1000 or when micro- and nanoparticles loaded with 3i-1000 were injected intramyocardially or intravenously, respectively. The compound inhibited stretch- and phenylephrine-induced hypertrophic response in neonatal rat cardiomyocytes. These results indicate significant potential for small molecules targeting GATA4–NKX2-5 interaction to promote myocardial repair after myocardial infarction and other cardiac injuries.

Exercise training versus T3 and T4 hormones treatment: The differential benefits of thyroid hormones on the parasympathetic drive of infarcted rats

AIMS

This study aimed to investigate whether beneficial effects of thyroid hormones are comparable to those provided by the aerobic exercise training, to verify its applicability as a therapeutic alternative to reverse the pathological cardiac remodeling post-infarction.

MATERIALS AND METHODS

Male rats were divided into SHAM-operated (SHAM), myocardial infarction (MI), MI subjected to exercise training (MIE), and MI who received T3 and T4 treatment (MIH) (n = 8/group). MI, MIE and MIH groups underwent an infarction surgery while SHAM was SHAM-operated. One-week post-surgery, MIE and MIH groups started the exercise training protocol (moderate intensity on treadmill), or the T3 (1.2 μg/100 g/day) and T4 (4.8 μg/100 g/day) hormones treatment by gavage, respectively, meanwhile SHAM and MI had no intervention for 9 weeks. The groups were accompanied until 74 days after surgery, when all animals were anesthetized, left ventricle echocardiography and femoral catheterization were performed, followed by euthanasia and left ventricle collection for morphological, oxidative stress, and intracellular kinases expression analysis.

KEY FINDINGS

Thyroid hormones treatment was more effective in cardiac dilation and infarction area reduction, while exercise training provided more protection against fibrosis. Thyroid hormones treatment increased the lipoperoxidation and decreased GSHPx activity as compared to MI group, increased the t-Akt2 expression as compared to SHAM group, and increased the vascular parasympathetic drive.

SIGNIFICANCE

Thyroid hormones treatment provided differential benefits on the LV function and autonomic modulation as compared to the exercise training. Nevertheless, the redox unbalance induced by thyroid hormones highlights the importance of more studies targeting the ideal duration of this treatment.

Inflammatory Response During Myocardial Infarction

The occlusion of a coronary artery by a thrombus generated on a ruptured atherosclerotic plaque has been pursued in the last decades as a determining event for the clinical outcome after myocardial infarction (MI). Yet, MI causes a cell death wave front, which triggers an inflammatory response to clear cellular debris, and which in excess can double the myocardial lesion and influence the clinical prognosis in the short and long term. Accordingly, proper, timely regulated inflammatory response has now been considered a second pivotal player in cardiac recovery after MI justifying the search for pharmacological strategies to modulate inflammatory effectors. This chapter reviews the key events and the main effectors of inflammation after myocardial ischemic insult, as well as the contribution of this phenomenon to the progression of atherosclerosis.

Orientin Reduces Myocardial Infarction Size via eNOS/NO Signaling and Thus Mitigates Adverse Cardiac Remodeling

Orientin is a flavonoid extracted from Chinese traditional herb, Polygonum orientale L. Previous study has reported that orientin protected myocardial from ischemia reperfusion injury. However, whether orientin could protect against cardiac remodeling after myocardial injury remains unclear. The aim of our study is to investigate the effects of orientin in the progression of cardiac remodeling after myocardial infarction (MI). Mice cardiac remodeling model was established by left coronary artery ligation surgery. Experimental groups were as follows: vehicle-sham, orientin-sham, vehicle-MI, and orientin-MI. Animals were treated with vehicle or orientin (40 mg/kg) for 25 days starting 3 days after surgery. After 4 weeks of MI, mice with orientin treatment had decreased mortality and improved cardiac function. Significantly, at 4 weeks post-MI, orientin treatment decreased fibrosis, inflammatory response, and cardiomyocyte apoptosis. Furthermore, orientin treatment attenuated the hypoxia-induced neonatal rat cardiomyocyte apoptosis and increased cell viability. Additionally, orientin supplementation mitigated oxidative stress in remodeling heart tissue and cardiomyocytes exposed to hypoxia as measured by 2′,7′-dichlorodihydrofluorescein diacetate fluorescent probe. Mechanistically, orientin promotes cardioprotection by activating the eNOS/NO signaling cascades, which was confirmed by eNOS inhibitor (L-NAME) in vitro and in vivo. Inhibition of oxidative stress by orientin via eNOS/NO signaling cascades in the heart may represent a potential therapy for cardiac remodeling.