Ventricular remodeling after myocardial infarction. Experimental observations and clinical implications

Enhancing miR-19a/b induced cardiomyocyte proliferation in infarcted hearts by alleviating oxidant stress and controlling miR-19 release

Fully restoring the lost population of cardiomyocytes and heart function remains the greatest challenge in cardiac repair post myocardial infarction. In this study, a pioneered highly ROS-eliminating hydrogel was designed to enhance miR-19a/b induced cardiomyocyte proliferation by lowering the oxidative stress and continuously releasing miR-19a/b in infarcted myocardium in situ. In vivo lineage tracing revealed that ∼20.47 % of adult cardiomyocytes at the injected sites underwent cell division in MI mice. In MI pig the infarcted size was significantly reduced from 40 % to 18 %, and thereby marked improvement of cardiac function and increased muscle mass. Most importantly, our treatment solved the challenge of animal death--all the treated pigs managed to live until their hearts were harvested at day 50. Therefore, our strategy provides clinical conversion advantages and safety for healing damaged hearts and restoring heart function post MI, which will be a powerful tool to battle cardiovascular diseases in patients.

Recovery From Left Ventricular Dysfunction

The treatment of heart failure is an evolving field of cardiology, with increasingly available therapeutics and significant disease burden. With the effective treatments available, we see a substantial patient population whose once reduced ejection fraction (EF) has normalized. Studies have assessed the natural history of these patients with improved EF and found improved mortality as compared with those patients with persistently reduced EF, with some evidence stating that each 5% increase in left ventricular EF correlates with a 4.9-fold decrease in the odds of mortality. This prognostic divergence has led to the recognition of this subset of patients as having a unique heart failure diagnosis, distinct from heart failure with reduced EF (HFrEF) or heart failure with preserved EF and to the adoption of the term heart failure with recovered EF. These patients, despite having improved mortality, do retain some of the molecular and histologic changes seen in HFrEF and are still at risk for decline in left ventricular function and adverse cardiac events, particularly when medical therapy is stopped. This distinction between recovery of EF and true myocardial recovery led to recent guidelines recommending continuation of guideline-directed medical therapy indefinitely, as well as surveillance echocardiography.

Treatment of sleep apnoea early after myocardial infarction with adaptive servo-ventilation: a proof-of-concept randomised controlled trial

BACKGROUND

Sleep disordered breathing (SDB) has been associated with less myocardial salvage and smaller infarct size reduction after acute myocardial infarction (AMI). The Treatment of sleep apnoea Early After Myocardial infarction with Adaptive Servo-Ventilation (TEAM-ASV I) trial investigated the effects of adding adaptive servo-ventilation (ASV) for SDB to standard therapy on the myocardial salvage index (MSI) and change in infarct size within 12 weeks after AMI.

METHODS

In this multicentre, randomised, open-label trial, patients with AMI and successful percutaneous coronary intervention within 24 h after symptom onset plus SDB (apnoea-hypopnoea index ≥15 events·h-1) were randomised to standard medical therapy alone (control) or plus ASV (starting 3.6±1.4 days post-AMI). The primary outcome was the MSI at 12 weeks post-AMI. Cardiac magnetic resonance (CMR) imaging was performed at ≤5 days and 12 weeks after AMI.

RESULTS

76 individuals were enrolled from February 2014 to August 2020; 39 had complete CMR data for analysis of the primary end-point. The MSI was significantly higher in the ASV versus control group (difference 14.6% (95% CI 0.14-29.1%); p=0.048). At 12 weeks, absolute (6.6 (95% CI 4.8-8.5) versus 2.8 (95% CI 0.9-4.8) % of left ventricular mass; p=0.003) and relative (44 (95% CI 30-57) versus 21 (95% CI 6-35) % of baseline; p=0.013) reductions in infarct size were greater in the ASV versus control group. No serious treatment-related adverse events occurred.

CONCLUSIONS

Early treatment of SDB with ASV improved the MSI and decreased infarct size at 12 weeks after AMI. Larger randomised trials are required to confirm these findings.

Pericardial Delivery of Sodium Alginate-Infusible Extracellular Matrix Composite Hydrogel Promotes Angiogenesis and Intercellular Electrical Conduction after Myocardial Infarction

Injectable extracellular matrix (iECM) is a versatile biological material with beneficial properties such as good degradability, promotion of cell survival, immunomodulation, and facilitation of vascular formation. However, intravenous injection of iECM faces challenges like a short retention time in vivo and low concentration at the lesion site. To address these issues, we prepared a composite hydrogel composed of sodium alginate and iECM and administered it via intrapericardial injection, forming a structure akin to cardiac patches within the pericardium. Compared with intramyocardial injection, intrapericardial injection avoids direct myocardial injury and ectopic tumor formation, offering less invasiveness and better biocompatibility. This study demonstrates that the sodium alginate/infusible extracellular matrix (SA/iECM) composite hydrogel can effectively prolong the local retention time of iECM in the heart, enhance electrical conduction between cardiomyocytes, promote angiogenesis at ischemic myocardial sites, inhibit apoptosis in the infarcted region, mitigate left ventricular remodeling postmyocardial infarction (MI), and improve cardiac function after infarction. Precise coordination of cardiomyocyte contraction and relaxation depends on the rhythmic occurrence of calcium-dependent action potentials. Cardiac dysfunction is partially attributed to the disruption of the excitation-contraction coupling (ECC) mechanism, which is associated with prolonged intracellular Ca2+ transients and alterations in contraction and relaxation Ca2+ levels. Our results show that the SA/iECM composite hydrogel improves electrical conduction, as evidenced by increased Cx43 expression and enhanced intercellular electrical connectivity. This research establishes that intrapericardial injection of a SA/iECM composite hydrogel is a safe and effective treatment modality, providing a theoretical basis for the use of biomaterials in MI therapy.

Comparative Cardioprotective Effectiveness: NOACs vs. Nattokinase-Bridging Basic Research to Clinical Findings

The use of non-vitamin K antagonist oral anticoagulants (NOACs) has brought a significant progress in the management of cardiovascular diseases, considered clinically superior to vitamin K antagonists (VKAs) particularly in the prevention and treatment of thromboembolic events. In addition, numerous advantages such as fixed dosing, lack of laboratory monitoring, and fewer food and drug-to-drug interactions make the use of NOACs superior to VKAs. While NOACs are synthetic drugs prescribed for specific conditions, nattokinase (NK) is a natural enzyme derived from food that has potential health benefits. Various experimental and clinical studies reported the positive effects of NK on the circulatory system, including the thinning of blood and the dissolution of blood clots. This enzyme showed not only fibrinolytic activity due to its ability to degrade fibrin, but also an affinity as a substrate for plasmin. Recent studies have shown that NK has additional cardioprotective effects, such as antihypertensive and anti-atherosclerotic effects. In this narrative review, we presented the cardioprotective properties of two different approaches that go beyond anticoagulation: NOACs and NK. By combining evidence from basic research with clinical findings, we aim to elucidate the comparative cardioprotective efficacy of these interventions and highlight their respective roles in modern cardiovascular care.

Non-coding RNA yREX3 from human extracellular vesicles exerts macrophage-mediated cardioprotection via a novel gene-methylating mechanism

BACKGROUND AND AIMS

Extracellular vesicles (EVs) secreted by cardiosphere-derived cells exert immunomodulatory effects through the transmission of small non-coding RNAs.

METHODS

The mechanism and role of yREX3, a small Y RNA abundant in EVs in myocardial injury, was investigated.

RESULTS

yREX3 attenuates cardiac ischaemic injury by selective DNA methylation. Synthetic yREX3 encapsulated in lipid nanoparticles triggers broad transcriptomic changes in macrophages, localizes to the nucleus, and mediates epigenetic silencing of protein interacting with C kinase-1 (Pick1) through methylation of upstream CpG sites. Moreover, yREX3 interacts with polypyrimidine tract binding protein 3 (PTBP3) to methylate the Pick1 gene locus in a DNA methyltransferase-dependent manner. Suppression of Pick1 in macrophages potentiates Smad3 signalling and enhances efferocytosis, minimizing heart necrosis in rats with myocardial infarction. Adoptive transfer of Pick1-deficient macrophages recapitulates the cardioprotective effects of yREX3 in vivo.

CONCLUSIONS

These findings highlight the role of a small Y RNA mined from EVs with a novel gene-methylating mechanism.

Remote myocardial fibrosis predicts adverse outcome in patients with myocardial infarction on clinical cardiovascular magnetic resonance imaging

BACKGROUND

Heart failure (HF) most commonly occurs in patients who have had a myocardial infarction (MI), but factors other than MI size may be deterministic. Fibrosis of myocardium remote from the MI is associated with adverse remodeling. We aimed to 1) investigate the association between remote myocardial fibrosis, measured using cardiovascular magnetic resonance (CMR) extracellular volume fraction (ECV), and HF and death following MI, 2) identify predictors of remote myocardial fibrosis in patients with evidence of MI and determine the relationship with infarct size.

METHODS

Multicenter prospective cohort study of 1199 consecutive patients undergoing CMR with evidence of MI on late gadolinium enhancement. Median follow-up was 1133 (895-1442) days. Cox proportional hazards modeling was used to identify factors predictive of the primary outcome, a composite of first hospitalization for HF (HHF) or all-cause mortality, post-CMR. Linear regression modeling was used to identify determinants of remote ECV.

RESULTS

Remote myocardial fibrosis was a strong predictor of primary outcome (χ2: 15.6, hazard ratio [HR]: 1.07 per 1% increase in ECV, 95% confidence interval [CI]: 1.04-1.11, p < 0.001) and was separately predictive of both HHF and death. The strongest predictors of remote ECV were diabetes, sex, natriuretic peptides, and body mass index, but, despite extensive phenotyping, the adjusted model R2 was only 0.283. The relationship between infarct size and remote fibrosis was very weak.

CONCLUSION

Myocardial fibrosis, measured using CMR ECV, is a strong predictor of HHF and death in patients with evidence of MI. The mechanisms underlying remote myocardial fibrosis formation post-MI remain poorly understood, but factors other than infarct size appear to be important.

Resistance exercise upregulates Irisin expression and suppresses myocardial fibrosis following myocardial infarction via activating AMPK-Sirt1 and inactivating TGFβ1-Smad2/3

AIM

To reveal the contribution of Irisin in the beneficial effects of resistance exercise on myocardial fibrosis (MF) and cardiac function in the mice with myocardial infarction (MI).

METHODS

The MI model was built by ligating the left anterior descending coronary artery in Fndc5 knockout mice (Fndc5-/-). Resistance exercise was started one week after surgery and continued for four weeks. In addition, H2O2, AICAR, recombinant human Irisin protein (rhIRISIN), and Sirt1 shRNA lentivirus (LV-Sirt1 shRNA) were used to intervene primary isolated cardiac fibroblasts (CFs). MF was observed through Masson staining, and apoptosis was assessed using TUNEL staining. MDA and T-SOD contents were detected by biochemical kits. The expression of proteins and genes was detected by Western blotting and RT-qPCR.

RESULTS

Resistance exercise increased Fndc5 mRNA level, inhibited the activation of TGFβ1-TGFβR2-Smad2/3 pathway, activated AMPK-Sirt1 pathway, reduced the levels of oxidative stress, apoptosis, and MF in the infarcted heart, and promoted cardiac function. However, Fndc5 knockout attenuated the protective effects of resistance exercise on the MI heart. Results of the in vitro experiments showed that AICAR and rhIRISIN intervention activated the AMPK-Sirt1 pathway and inactivated the TGFβ1-Smad2/3 pathway, and promoted apoptosis in H2O2-treated CFs. Notably, these effects of rhIRISIN intervention, except for the TGFβR2 expression, were attenuated by LV-Sirt1 shRNA.

CONCLUSION

Resistance exercise upregulates Fndc5 expression, activates AMPK-Sirt1 pathway, inhibits the activation of TGFβ1-Smad2/3 pathway, attenuates MF, and promotes cardiac function after MI.

Role of inflammation and evidence for the use of colchicine in patients with acute coronary syndrome

Acute Coronary Syndrome (ACS) significantly contributes to cardiovascular death worldwide. ACS may arise from the disruption of an atherosclerotic plaque, ultimately leading to acute ischemia and myocardial infarction. In the pathogenesis of atherosclerosis, inflammation assumes a pivotal role, not solely in the initiation and complications of atherosclerotic plaque formation, but also in the myocardial response to ischemic insult. Acute inflammatory processes, coupled with time to reperfusion, orchestrate ischemic and reperfusion injuries, dictating infarct magnitude and acute left ventricular (LV) remodeling. Conversely, chronic inflammation, alongside neurohumoral activation, governs persistent LV remodeling. The interplay between chronic LV remodeling and recurrent ischemic episodes delineates the progression of the disease toward heart failure and cardiovascular death. Colchicine exerts anti-inflammatory properties affecting both the myocardium and atherosclerotic plaque by modulating the activity of monocyte/macrophages, neutrophils, and platelets. This modulation can potentially result in a more favorable LV remodeling and forestalls the recurrence of ACS. This narrative review aims to delineate the role of inflammation across the different phases of ACS pathophysiology and describe the mechanistic underpinnings of colchicine, exploring its purported role in modulating each of these stages.

MRI-based adrenal gland volume is associated with cardiovascular alterations in individuals without prior cardiovascular disease

Aim of this study was to analyse the associations of cardiovascular health and adrenal gland volume as a rather new imaging biomarker of chronic hypothalamic-pituitary-adrenal (HPA) axis activation. The study population originates from the KORA population-based cross-sectional prospective cohort. 400 participants without known cardiovascular disease underwent a whole-body MRI. Manual segmentation of adrenal glands was performed on VIBE-Dixon gradient-echo sequence. MRI based evaluation of cardiac parameters was achieved semi-automatically. Cardiometabolic risk factors were obtained through standardized interviews and medical examination. Univariate and multivariate associations were derived. Bi-directional causal mediation analysis was performed. 351 participants were eligible for analysis (56 ± 9.1 years, male 58.7%). In multivariate analysis, significant associations were observed between adrenal gland volume and hypertension (outcome hypertension: Odds Ratio = 1.11, 95% CI [1.01, 1.21], p = 0.028), left ventricular remodelling index (LVRI) (outcome LVRI: β = 0.01, 95% CI [0.00, 0.02], p = 0.011), and left ventricular (LV) wall thickness (outcome LV wall thickness: β = 0.06, 95% CI [0.02, 0.09], p = 0.005). In bi-directional causal mediation analysis adrenal gland volume had a borderline significant mediating effect on the association between hypertension and LVRI (p = 0.052) as well as wall thickness (p = 0.054). MRI-based assessment of adrenal gland enlargement is associated with hypertension and LV remodelling. Adrenal gland volume may serve as an indirect cardiovascular imaging biomarker.

Exploring the role of pericardial miRNAs and exosomes in modulating cardiac fibrosis

The potential of the pericardial space as a therapeutic delivery tool for cardiac fibrosis and heart failure (HF) treatment has yet to be elucidated. Recently, miRNAs and exosomes have been discovered to be present in human pericardial fluid (PF). Novel studies have shown characteristic human PF miRNA compositions associated with cardiac diseases and higher miRNA expressions in PF compared to peripheral blood. Five key studies found differentially expressed miRNAs in HF, angina pectoris, aortic stenosis, ventricular tachycardia, and congenital heart diseases with either atrial fibrillation or sinus rhythm. As miRNA-based therapeutics for cardiac fibrosis and HF showed promising results in several in vivo studies for multiple miRNAs, we hypothesize a potential role of miRNA-based therapeutics delivered through the pericardial cavity. This is underlined by the favorable results of the first phase 1b clinical trial in this emerging field. Presenting the first human miRNA antisense drug trial, inhibition of miR-132 by intravenous administration of a novel antisense oligonucleotide, CDR132L, established efficacy in reducing miR-132 in plasma samples in a dose-dependent manner. We screened the literature, provided an overview of the miRNAs and exosomes present in PF, and drew a connection to those miRNAs previously elucidated in cardiac fibrosis and HF. Further, we speculate about clinical implications and potential delivery methods.

Incremental value of high-risk CMR attributes to predict adverse remodeling after ST-segment elevation myocardial infarction across LVEF categories

BACKGROUND

A couple of cardiac magnetic resonance (CMR) attributes strongly predict adverse remodeling after ST-segment elevation myocardial infarction (STEMI); however, the value of incorporating high-risk CMR attributes, particularly, in patients with non-reduced ejection fraction, remains undetermined. This study sought to evaluate the independent and incremental predictive value of a multiparametric CMR approach for adverse remodeling after STEMI across left ventricular ejection fraction (LVEF) categories.

METHODS

A total of 157 patients with STEMI undergoing primary percutaneous coronary intervention were prospectively enrolled. Adverse remodeling was defined as ≥20% enlargement in left ventricular end-diastolic volume from index admission to 3 months of follow-up.

RESULTS

Adverse remodeling occurred in 23.6% of patients. After adjustment for clinical risk factors, a stroke volume index <29.6 mL/m2, a global longitudinal strain >-7.5%, an infarct size >39.2%, a microvascular obstruction >4.9%, and a myocardial salvage index <36.4 were independently associated with adverse remodeling. The incidence of adverse remodeling increased with the increasing number of high-risk CMR attributes, regardless of LVEF (LVEF ≤ 40%: P = 0.026; 40% < LVEF < 50%: P = 0.001; LVEF ≥ 50%: P < 0.001). The presence of ≥4 high-risk attributes was an independent predictor of LV adverse remodeling (70.0% vs. 16.8%, adjusted OR 9.68, 95 CI% 3.25-28.87, P < 0.001). Furthermore, the number of high-risk CMR attributes had an incremental predictive value over reduced LVEF and baseline clinical risk factors (AUC: 0.81 vs. 0.68; P = 0.002).

CONCLUSIONS

High-risk CMR attributes showed a significant association with adverse remodeling after STEMI across LVEF categories. This imaging-based model provided incremental value for adverse remodeling over traditional clinical factors and LVEF.

A review of therapeutic approaches for post-infarction left ventricular remodeling

Left ventricular remodeling is an adaptive process initially developed in response to acute myocardial infarction (AMI), but it ends up with negative adverse outcomes such as infarcted wall thinning, ventricular dilation, and cardiac dysfunction. A prolonged excessive inflammatory reaction to cardiomyocytes death and necrosis plays the crucial role in the pathophysiological mechanisms. The pharmacological treatment includes nitroglycerine, β-blockers, ACEi/ARBs, SGLT2i, mineralocorticoid receptor antagonists, and some miscellaneous aspects. Stem cells therapy, CD34+ cells transplantation and gene therapy constitute the promissing therapeutic approaches for post AMI cardiac remodeling, thereby enhancing angiogenesis, cardiomyocytes differenciation and left ventricular function on top of inhibiting apoptosis, inflammation, and collagen deposition. All these lead to reduce infarct size, scar formation and myocardial fibrosis.

Myocardial injury in dogs: a retrospective analysis on etiological, echocardiographic, electrocardiographic, therapeutic, and outcome findings in 102 cases

INTRODUCTION

In dogs, myocardial injury (MI) is a poorly characterized clinical entity; therefore, this study aimed to provide a detailed description of dogs affected by this condition.

ANIMALS, MATERIALS, AND METHODS

Dogs diagnosed with MI according to the concentration of cardiac troponin I (cTnI) were retrospectively searched. Signalment, diagnostic, therapeutic, and outcome data were retrieved. Dogs were divided into six echocardiographic (dilated cardiomyopathy phenotype; hypertrophic cardiomyopathy phenotype; hypertrophic cardiomyopathy phenotype with systolic dysfunction; abnormal echogenicity only; endocarditis; and no echocardiographic abnormalities suggestive of MI), four electrocardiographic (abnormalities of impulse formation; abnormalities of impulse conduction; abnormalities of ventricular repolarization; and no electrocardiographic abnormalities suggestive of MI), and nine etiological (infective; inflammatory; neoplastic; metabolic; toxic; nutritional; immune-mediated; traumatic/mechanical; and unknown) categories. Statistical analysis was performed to compare cTnI values among different categories and analyze survival.

RESULTS

One hundred two dogs were included. The median cTnI value was 3.71 ng/mL (0.2-180 ng/mL). Echocardiographic and electrocardiographic abnormalities were documented in 86 of 102 and 89 of 102 dogs, respectively. Among echocardiographic and electrocardiographic categories, the dilated cardiomyopathy phenotype (n = 52) and abnormalities of impulse formation (n = 67) were overrepresented, respectively. Among dogs in which a suspected etiological trigger was identified (68/102), the infective category was overrepresented (n = 20). Among dogs belonging to different echocardiographic, electrocardiographic, and etiological categories, cTnI did not differ significantly. The median survival time was 603 days; only eight of 102 dogs died due to MI.

CONCLUSIONS

Dogs with MI often have an identifiable suspected trigger, show various echocardiographic and electrocardiographic abnormalities, and frequently survive to MI-related complications.

Effect of sacubitril-valsartan on left ventricular remodeling in patients with acute myocardial infarction after primary percutaneous coronary intervention: a systematic review and meta-analysis

Background

Sacubitril-valsartan has been widely reported for reducing the risk of cardiovascular death and improving left ventricular remodeling in patients with heart failure (HF). However, the effect of sacubitril-valsartan in patients with acute myocardial infarction (AMI) remains controversial. Therefore, we conducted this meta-analysis to investigate whether sacubitril-valsartan could reverse left ventricular remodeling and reduce cardiovascular adverse events in AMI patients after primary percutaneous coronary intervention (PPCI).

Materials and methods

Two researchers independently retrieved the relevant literature from PubMed, Embase, The Cochrane Library, China National Knowledge Infrastructure (CNKI), and the Wanfang database. The retrieval time was limited from inception to 1 June 2023. Randomized controlled trials (RCTs) meeting the inclusion criteria were included and analyzed.

Results

In total, 21 RCTs involving 2442 AMI patients who underwent PPCI for revascularization were included in this meta-analysis. The meta-analysis showed that compared with the angiotensin-converting enzyme inhibitors (ACEI)/angiotensin receptor blockers (ARB), sacubitril-valsartan treatment in AMI patients after PPCI significantly reduced left ventricular end-diastolic dimension (LVEDD) (weighted mean difference (WMD) -3.11, 95%CI: -4.05∼-2.16, p < 0.001), left ventricular end-diastolic volume (LVEDV) (WMD -7.76, 95%CI: -12.24∼-3.27, p = 0.001), left ventricular end-systolic volume (LVESV) (WMD -6.80, 95%CI: -9.45∼-4.15, p < 0.001) and left ventricular end-systolic dimension (LVESD) (WMD -2.53, 95%CI: -5.30-0.24, p < 0.001). Subgroup analysis according to the dose of sacubitril-valsartan yielded a similar result. Meanwhile, PPCI patients using sacubitril-valsartan therapy showed lower risk of major adverse cardiac events (MACE) (OR = 0.36, 95%CI: 0.28-0.46, p < 0.001), myocardial reinfarction (OR = 0.54, 95%CI: 0.30-0.98, p = 0.041) and HF (OR = 0.35, 95%CI: 0.26-0.47, p < 0.001) without increasing the risk of renal insufficiency, hyperkalemia, or symptomatic hypotension. At the same time, the change of LV ejection fraction (LVEF) (WMD 3.91, 95%CI: 3.41-4.41, p < 0.001), 6 min walk test (6MWT) (WMD 43.56, 95%CI: 29.37-57.76, p < 0.001) and NT-proBNP level (WMD -130.27, 95%CI: -159.14∼-101.40, p < 0.001) were statistically significant.

Conclusion

In conclusion, our meta-analysis indicates that compared with ACEI/ARB, sacubitril-valsartan may be superior to reverse left ventricular remodeling, improve cardiac function, and effectively reduce the risk of MACE, myocardial reinfarction, and HF in AMI patients after PPCI during follow-up without increasing the risk of adverse reactions including renal insufficiency, hyperkalemia, and symptomatic hypotension.

Role of Vasoactive Hormone-Induced Signal Transduction in Cardiac Hypertrophy and Heart Failure

Heart failure is the common concluding pathway for a majority of cardiovascular diseases and is associated with cardiac dysfunction. Since heart failure is invariably preceded by adaptive or maladaptive cardiac hypertrophy, several biochemical mechanisms have been proposed to explain the development of cardiac hypertrophy and progression to heart failure. One of these includes the activation of different neuroendocrine systems for elevating the circulating levels of different vasoactive hormones such as catecholamines, angiotensin II, vasopressin, serotonin and endothelins. All these hormones are released in the circulation and stimulate different signal transduction systems by acting on their respective receptors on the cell membrane to promote protein synthesis in cardiomyocytes and induce cardiac hypertrophy. The elevated levels of these vasoactive hormones induce hemodynamic overload, increase ventricular wall tension, increase protein synthesis and the occurrence of cardiac remodeling. In addition, there occurs an increase in proinflammatory cytokines and collagen synthesis for the induction of myocardial fibrosis and the transition of adaptive to maladaptive hypertrophy. The prolonged exposure of the hypertrophied heart to these vasoactive hormones has been reported to result in the oxidation of catecholamines and serotonin via monoamine oxidase as well as the activation of NADPH oxidase via angiotensin II and endothelins to promote oxidative stress. The development of oxidative stress produces subcellular defects, Ca2+-handling abnormalities, mitochondrial Ca2+-overload and cardiac dysfunction by activating different proteases and depressing cardiac gene expression, in addition to destabilizing the extracellular matrix upon activating some metalloproteinases. These observations support the view that elevated levels of various vasoactive hormones, by producing hemodynamic overload and activating their respective receptor-mediated signal transduction mechanisms, induce cardiac hypertrophy. Furthermore, the occurrence of oxidative stress due to the prolonged exposure of the hypertrophied heart to these hormones plays a critical role in the progression of heart failure.

Research and application of hydrogel-encapsulated mesenchymal stem cells in the treatment of myocardial infarction

Myocardial infarction (MI) stands out as a highly lethal disease that poses a significant threat to global health. Worldwide, heart failure resulting from MI remains a leading cause of human mortality. Mesenchymal stem cell (MSC) therapy has emerged as a promising therapeutic approach, leveraging its intrinsic healing properties. Nevertheless, pervasive issues, including a low cell retention rate, suboptimal survival rate, and incomplete differentiation of MSCs, present formidable challenges for further research. The introduction and advancement of biomaterials have offered a novel avenue for the exploration of MSC therapy in MI, marking considerable progress thus far. Notably, hydrogels, among the representative biomaterials, have garnered extensive attention within the biomedical field. This review delves into recent advancements, specifically focusing on the application of hydrogels to augment MSC therapy for cardiac tissue regeneration in MI.

Neutrophils facilitate the epicardial regenerative response after zebrafish heart injury

Despite extensive studies on endogenous heart regeneration within the past 20 years, the players involved in initiating early regeneration events are far from clear. Here, we assessed the function of neutrophils, the first-responder cells to tissue damage, during zebrafish heart regeneration. We detected rapid neutrophil mobilization to the injury site after ventricular amputation, peaking at 1-day post-amputation (dpa) and resolving by 3 dpa. Further analyses indicated neutrophil mobilization coincides with peak epicardial cell proliferation, and recruited neutrophils associated with activated, expanding epicardial cells at 1 dpa. Neutrophil depletion inhibited myocardial regeneration and significantly reduced epicardial cell expansion, proliferation, and activation. To explore the molecular mechanism of neutrophils on the epicardial regenerative response, we performed scRNA-seq analysis of 1 dpa neutrophils and identified enrichment of the FGF and MAPK/ERK signaling pathways. Pharmacological inhibition of FGF signaling indicated its' requirement for epicardial expansion, while neutrophil depletion blocked MAPK/ERK signaling activation in epicardial cells. Ligand-receptor analysis indicated the EGF ligand, hbegfa, is released from neutrophils and synergizes with other FGF and MAPK/ERK factors for induction of epicardial regeneration. Altogether, our studies revealed that neutrophils quickly motivate epicardial cells, which later accumulate at the injury site and contribute to heart regeneration.

Circadian Influences on Myocardial Ischemia-Reperfusion Injury and Heart Failure

The impact of circadian rhythms on cardiovascular function and disease development is well established, with numerous studies in genetically modified animals emphasizing the circadian molecular clock's significance in the pathogenesis and pathophysiology of myocardial ischemia and heart failure progression. However, translational preclinical studies targeting the heart's circadian biology are just now emerging and are leading to the development of a novel field of medicine termed circadian medicine. In this review, we explore circadian molecular mechanisms and novel therapies, including (1) intense light, (2) small molecules modulating the circadian mechanism, and (3) chronotherapies such as cardiovascular drugs and meal timings. These promise significant clinical translation in circadian medicine for cardiovascular disease. (4) Additionally, we address the differential functioning of the circadian mechanism in males versus females, emphasizing the consideration of biological sex, gender, and aging in circadian therapies for cardiovascular disease.

Establishment and validation of a prediction model for nonrecovery of left ventricular ejection fraction in acute myocardial infarction patients combined with decreased left ventricular ejection fraction

BACKGROUND

This study aimed to investigate the risk factors for nonrecovery of left ventricular ejection fraction (LVEF) during follow-up in patients with acute myocardial infarction (AMI) who underwent percutaneous coronary intervention (PCI) combined with reduced LVEF, and establish and verify a risk prediction model based on these factors.

METHODS

In this study, patients with AMI who underwent PCI in a high-volume PCI center between December 2018 and December 2021 were consecutively enrolled, screened, and randomly assigned to the model establishment and validation cohorts. A predictive model method based on least absolute shrinkage and selection operator regression was used for establishment and validation.

RESULTS

Cardiac troponin I, myoglobin, left ventricular end-diastolic dimension, multivessel disease, and no-reflow were identified as potential predictors of LVEF recovery failure. The areas under the curve were 0.703 and 0.665 in the model establishment and validation cohorts, respectively, proving that the prediction model had some predictive ability. The calibration curves of the two cohorts showed good agreement with those of the nomogram model. In addition, the decision curve analysis showed that the model had a net clinical benefit.

CONCLUSION

This prediction model can assess the risk of nonrecovery of LVEF in patients with AMI undergoing PCI combined with LVEF reduction during follow-up, and conveniently screen high-risk patients with nonrecoverable LVEF early.

Prognostic Implication of Platelet Reactivity According to Left Ventricular Systolic Dysfunction Status in Patients Treated With Drug-Eluting Stent Implantation: Analysis of the PTRG-DES Consortium

BACKGROUND

Coronary artery disease patients undergoing percutaneous coronary intervention (PCI) often exhibit reduced left ventricular ejection fraction (LVEF). However, the impact of LV dysfunction status in conjunction with platelet reactivity on clinical outcomes has not been previously investigated.

METHODS

From the multicenter PTRG-DES (Platelet function and genoType-Related long-term prognosis in DES-treated patients) consortium, the patients were classified as preserved-EF (PEF: LVEF ≥ 50%) and reduced-EF (REF: LVEF< 5 0%) group by echocardiography. Platelet reactivity was measured using VerifyNow P2Y12 assay and high platelet reactivity (HPR) was defined as PRU ≥ 252. The major adverse cardiac and cerebrovascular events (MACCEs) were a composite of death, myocardial infarction, stent thrombosis and stroke at 5 years after PCI. Major bleeding was defined as Bleeding Academic Research Consortium bleeding types 3-5.

RESULTS

A total of 13,160 patients from PTRG-DES, 9,319 (79.6%) patients with the results of both PRU and LVEF were analyzed. The incidence of MACCE and major bleeding was higher in REF group as compared with PEF group (MACCEs: hazard ratio [HR] 2.17, P < 0.001, 95% confidence interval [CI] 1.85-2.55; major bleeding: HR 1.78, P < 0.001, 95% CI 1.39-2.78). The highest rate of MACCEs was found in patients with REF and HPR, and the difference between the groups was statistically significant (HR 3.14 in REF(+)/HPR(+) vs. PEF(+)/HPR(-) group, P < 0.01, 95% CI 2.51-3.91). The frequency of major bleeding was not associated with the HPR in either group.

CONCLUSION

LV dysfunction was associated with an increased incidence of MACCEs and major bleeding in patients who underwent PCI. The HPR status further exhibited significant increase of MACCEs in patients with LV dysfunction in a large, real-world registry.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT04734028.

Induced Pluripotent Stem Cell-Derived Cardiomyocytes Therapy for Ischemic Heart Disease in Animal Model: A Meta-Analysis

Ischemic heart disease (IHD) poses a significant challenge in cardiovascular health, with current treatments showing limited success. Induced pluripotent derived-cardiomyocyte (iPSC-CM) therapy within regenerative medicine offers potential for IHD patients, although its clinical impacts remain uncertain. This study utilizes meta-analysis to assess iPSC-CM outcomes in terms of efficacy and safety in IHD animal model studies. A meta-analysis encompassing PUBMED, ScienceDirect, Web of Science, and the Cochrane Library databases, from inception until October 2023, investigated iPSC therapy effects on cardiac function and safety outcomes. Among 51 eligible studies involving 1012 animals, despite substantial heterogeneity, the iPSC-CM transplantation improved left ventricular ejection fraction (LVEF) by 8.23% (95% CI, 7.15 to 9.32%; p < 0.001) compared to control groups. Additionally, cell-based treatment reduced the left ventricle fibrosis area and showed a tendency to reduce left ventricular end-systolic volume (LVESV) and end-diastolic volume (LVEDV). No significant differences emerged in mortality and arrhythmia risk between iPSC-CM treatment and control groups. In conclusion, this meta-analysis indicates iPSC-CM therapy's promise as a safe and beneficial intervention for enhancing heart function in IHD. However, due to observed heterogeneity, the efficacy of this treatment must be further explored through large randomized controlled trials based on rigorous research design.

ISE/ISHNE expert consensus statement on the ECG diagnosis of left ventricular hypertrophy: The change of the paradigm

The ECG diagnosis of LVH is predominantly based on the QRS voltage criteria. The classical paradigm postulates that the increased left ventricular mass generates a stronger electrical field, increasing the leftward and posterior QRS forces, reflected in the augmented QRS amplitude. However, the low sensitivity of voltage criteria has been repeatedly documented. We discuss possible reasons for this shortcoming and proposal of a new paradigm. The theoretical background for voltage measured at the body surface is defined by the solid angle theorem, which relates the measured voltage to spatial and non-spatial determinants. The spatial determinants are represented by the extent of the activation front and the distance of the recording electrodes. The non-spatial determinants comprise electrical characteristics of the myocardium, which are comparatively neglected in the interpretation of the QRS patterns. Various clinical conditions are associated with LVH. These conditions produce considerable diversity of electrical properties alterations thereby modifying the resultant QRS patterns. The spectrum of QRS patterns observed in LVH patients is quite broad, including also left axis deviation, left anterior fascicular block, incomplete and complete left bundle branch blocks, Q waves, and fragmented QRS. Importantly, the QRS complex can be within normal limits. The new paradigm stresses the electrophysiological background in interpreting QRS changes, i.e., the effect of the non-spatial determinants. This postulates that the role of ECG is not to estimate LV size in LVH, but to understand and decode the underlying electrical processes, which are crucial in relation to cardiovascular risk assessment.

Metabolic signatures in post-myocardial infarction heart failure, including insights into prediction, intervention, and prognosis

Heart failure (HF) is a prevalent long-term complication of myocardial infarction (MI). The incidence of post-MI HF is high, and patients with the condition have a poor prognosis. Accurate identification of individuals at high risk for post-MI HF is crucial for implementation of a protective and ideally personalized strategy to prevent fatal events. Post-MI HF is characterized by adverse cardiac remodeling, which results from metabolic changes in response to long-term ischemia. Moreover, various risk factors, including genetics, diet, and obesity, can influence metabolic pathways in patients. This review focuses on the metabolic signatures of post-MI HF that could serve as non-invasive biomarkers for early identification in high-risk populations. We also explore how metabolism participates in the pathophysiology of post-MI HF. Furthermore, we discuss the potential of metabolites as novel targets for treatment of post-MI HF and as biomarkers for prognostic evaluation. It is expected to provide valuable suggestions for the clinical prevention and treatment of post-MI HF from a metabolic perspective.

Mechanism of pro-MMP9 activation in co-culture of pro-inflammatory macrophages and cardiomyocytes

OBJECTIVE

A wide range of cardiac diseases is associated with inflammation. "Inflamed" heart tissue is infiltrated with pro-inflammatory macrophages which extensively secrete matrix metalloproteinase 9 (MMP9), a regulator of extracellular matrix turnover. As MMP9 is released from macrophages in a latent form, it requires activation. The present study addresses the role of cardiomyocytes in the course of this activation process.

METHODS AND RESULTS

In mono- and co-cultures of pro-inflammatory rat macrophages (bone marrow-derived and peritoneal) and cardiomyocytes (H9C2 cell line) gelatin zymography demonstrated that activated macrophages robustly secreted latent pro-MMP9, whereas cardiomyocytes could not produce the enzyme. Co-culturing of the two cell species was critical for pro-MMP9 activation and was also accompanied by processing of cardiomyocyte-secreted pro-MMP2. A cascade of pro-MMP9 activation was initiated on macrophage membrane with pro-MMP2 cleavage. Namely, pro-inflammatory macrophages expressed an active membrane type 1 MMP (MT1MMP), which activated pro-MMP2, which in turn converted pro-MMP9. Downregulation of MT1MMP in macrophages by siRNA abolished activation of both pro-MMP2 and pro-MMP9 in co-culture. In addition, both cell species secreted MMP13 as a further pro-MMP9 activator. In co-culture, activation of pro-MMP13 occurred on membranes of macrophages and was enhanced in presence of active MMP2. Using incubations with recombinant MMPs and isolated macrophage membranes, we demonstrated that while both MMP2 and MMP13 individually had the ability to activate pro-MMP9, their combined action provided a synergistic effect.

CONCLUSION

Activation of pro-MMP9 in a co-culture of pro-inflammatory macrophages and cardiomyocytes was the result of a complex interaction of several MMPs on the cell membrane and in the extracellular space. Both cell types contributed critically to pro-MMP9 processing.

Association of aortic stiffness early post myocardial infarction with left ventricular remodelling

BACKGROUND

Adverse left ventricular (LV) remodelling after myocardial infarction is associated with heart failure. We investigated whether aortic stiffness during acute ST-segment elevation myocardial infarction is associated with LV remodelling at long-term follow-up.

METHODS

In 109 patients within 48 h of myocardial infarction post-primary percutaneous coronary intervention and after 2 years, we measured: (a) carotid to femoral pulse wave velocity (PWV), (b) LV global longitudinal strain (GLS) and left atrial strain using speckle-tracking echocardiography, (c) PWV/GLS ratio as a surrogate marker of ventricular-arterial interaction, and (d) LV end-diastolic and end-systolic volumes. A > 15% decrease from the baseline in LV end-systolic volume at 2-year follow-up was considered as a criterion of reverse LV remodelling.

RESULTS

Compared with baseline, all patients had reduced PWV, LV end-diastolic and end-systolic volumes while PWV/GLS, GLS and reservoir left atrial strain were improved (p < .05) after 2 years. Baseline values of PWV, GLS, PWV/GLS ratio and reservoir left atrial strain were associated with percentage change of LV end-systolic volume at 2 years (p < .05). Multivariable analysis revealed that lower baseline values of PWV and a less impaired GLS and PWV/GLS were independently associated with reverse LV remodelling at 2 years with a C-statistic of .748, .711 and .787, respectively.

CONCLUSION

Aortic stiffness early post-infarction determines LV remodelling after 2 years of the ischemic event despite post successful revascularization.

CLINICAL TRIAL REGISTRATION-URL

http://www.

CLINICALTRIALS

gov. Unique identifier: NCT03984123, 30/04/2020.

Exosomal Cargo: Pro-angiogeneic, anti-inflammatory, and regenerative effects in ischemic and non-ischemic heart diseases - A comprehensive review

Heart diseases are the primary cause of mortality and morbidity worldwide which inflict a heavy social and economic burden. Among heart diseases, most deaths are due to myocardial infarction (MI) or heart attack, which occurs when a decrement in blood flow to the heart causes injury to cardiac tissue. Despite several available diagnostic, therapeutic, and prognostic approaches, heart disease remains a significant concern. Exosomes are a kind of small extracellular vesicles released by different types of cells that play a part in intercellular communication by transferring bioactive molecules important in regenerative medicine. Many studies have reported the diagnostic, therapeutic, and prognostic role of exosomes in various heart diseases. Herein, we reviewed the roles of exosomes as new emerging agents in various types of heart diseases, including ischemic heart disease, cardiomyopathy, arrhythmia, and valvular disease, focusing on pathogenesis, therapeutic, diagnostic, and prognostic roles in different areas. We have also mentioned different routes of exosome delivery to target tissues, the effects of preconditioning and modification on exosome's capability, exosome production in compliance with good manufacturing practice (GMP), and their ongoing clinical applications in various medical contexts to shed light on possible clinical translation.

The promotion of sestrin2/AMPK signaling by HIF-1α overexpression enhances the damage caused by acute myocardial infarction

OBJECTIVE

Acute myocardial infarction (AMI), is a serious form of coronary heart disease. The present study sought to investigate the impact of HIF-1α on AMI, along with its fundamental mechanism.

METHODS

Sprague-Dawley (SD) rats were used to conduct an AMI model. 2,3,5-triphenyl-2H-tetrazolium chloride (TTC) staining was used examine the region of myocardial infract area at various time intervals. Protein expression levels were detected using western blotting. The rats were randomly divided into sham, model, negative control (NC), HIF-1α overexpression (HIF-1α-OE), and HIF-1α-OE+ si-sestrin2 groups. We examined the impact of HIF-1α overexpression on AMI rats using Haematoxylin-Eosin (H&E) staining, TTC staining, enzyme-linked immunosorbent assay (ELISA), TdT-mediated dUTP Nick-End Labeling (TUNEL) assay, and immunohistochemistry (IHC) staining.

RESULTS

According to the TTC findings, the region affected by myocardial infarction reached its peak at day 14. Based on the results from the western blot analysis, the levels of HIF-1α and sestrin2 were found the minimum on day 28. Subsequently, we discovered that the overexpression of HIF-1α rescued the cardiac function parameters, improved the morphology of myocardial tissue, and mitigated inflammation. Furthermore, the overexpression of HIF-1α led to a reduction in the levels of MDA and an increase in the levels of SOD. Moreover, the overexpression of HIF-1α resulted in a decrease in cellular apoptosis. This result was confirmed by the expression levels of Bcl-2 and Bax. Nevertheless, the defensive impact of elevated HIF-1α expression was somewhat counteracted by the suppression of sestrin2. In terms of mechanism, the overexpression of HIF-1α enhanced the levels of sestrin2 and the protein adenosine monophosphate activated kinase (AMPK).

CONCLUSION

Our research suggests that the overexpression of HIF-1α may rescue the damage to myocardial tissue, and this effect is associated with the sestrin2/AMPK signaling pathway. Our study provides a novel comprehension of the protective effects of HIF-1α overexpression on AMI.

Pattern and Prognostic Impact of Regional Wall Motion Abnormalities in 255 697 Men and 236 641 Women Investigated with Echocardiography

Background Regional wall motion abnormalities (WMAs) after myocardial infarction are associated with adverse remodeling and increased mortality in the short to medium term. Their long-term prognostic impact is less well understood. Methods and Results Via the National Echo Database of Australia (2000-2019), we identified normal wall motion versus WMA for each left ventricular wall among 492 338 individuals aged 61.9±17.9 years. The wall motion score index was also calculated. We then examined actual 1- and 5-year mortality, plus adjusted risk of long-term mortality according to WMA status. Overall, 39 346/255 697 men (15.4%) and 17 834/236 641 women (7.5%) had a WMA. The likelihood of a WMA was associated with increasing age and greater systolic/diastolic dysfunction. A defect in the inferior versus anterior wall was the most and least common WMA in men (8.0% and 2.5%) and women (3.3% and 1.1%), respectively. Any WMA increased 5-year mortality from 17.5% to 29.7% in men and from 14.9% to 30.8% in women. Known myocardial infarction (hazard ratio [HR], 0.86 [95% CI, 0.80-0.93]) or revascularization (HR, 0.87 [95% CI, 0.82-0.92]) was independently associated with a better prognosis, whereas men (1.22-fold increase) and those with greater systolic/diastolic dysfunction had a worse prognosis. Among those with any WMA, apical (HR, 1.08 [95% CI, 1.02-1.13]) or inferior (HR, 1.09 [95% CI, 1.04-1.15]) akinesis, dyskinesis or aneurysm, or a wall motion score index >3.0 conveyed the worst prognosis. Conclusions In a large real-world clinical cohort, twice as many men as women have a WMA, with inferior WMA the most common. Any WMA confers a poor prognosis, especially inferoapical akinesis/dyskinesis/aneurysm.

The Effect of Diabetes Mellitus on Cardiac Remodeling and Overall Clinical Outcomes in Patients With Acute Myocardial Infarction: A Single-Center Retrospective Study in Saudi Arabia

BACKGROUND

Diabetes mellitus (DM) is a major chronic condition that is considered a strong indicator of poor cardiovascular outcomes, such as recurrent infarction and heart failure (HF), in individuals with acute myocardial infarction (AMI). However, the concept of left ventricular remodeling (LVR) following AMI in DM patients is not well understood and studied in Saudi Arabia. Thus, the aim of this study is to assess the association between LVR and DM in patients presenting with ST-elevation myocardial infarction (STEMI) who had reperfusion therapy with optimal medical therapy after percutaneous coronary intervention (PCI).

METHODS

In this retrospective cohort study, 171 patients diagnosed with AMI who visited King Faisal Cardiac Center in King Abdulaziz Medical City, National Guard Hospital, Jeddah, Saudi Arabia, were chosen via the convenience sampling method. The study included patients with AMI who received echocardiograms upon admission and during a follow-up period of six to 12 months. The patients were divided into two groups based on their diabetic status: diabetic (DM) and non-diabetic (non-DM). To collect the data, trained medical students supervised by the principal investigator used the patients' medical records.

RESULTS

The study showed that DM patients were more likely to have a history of hypertension, dyslipidemia, smoking, and stress hyperglycemia and had a higher hospitalization rate compared to the non-DM group. Although there was no statistically significant difference (p=0.253), both groups had a higher incidence of the left main trunk and/or left anterior descending artery affected. Regarding the echocardiographic finding, there were no significant differences between the two groups in terms of left ventricular ejection fraction, left ventricular internal diameter at end-diastole, left ventricular internal diameter at end-systole, and interventricular septum thickness.

CONCLUSION

This paper suggests that there is no significant correlation between DM and non-DM patients in terms of LVR after AMI. However, DM patients had a statistically significant increased risk of developing HF and valvular heart disease compared to non-DM patients after AMI.

miR-182/183-Rasa1 axis induced macrophage polarization and redox regulation promotes repair after ischemic cardiac injury

Few therapies have produced significant improvement in cardiac structure and function after ischemic cardiac injury (ICI). Our possible explanation is activation of local inflammatory responses negatively impact the cardiac repair process following ischemic injury. Factors that can alter immune response, including significantly altered cytokine levels in plasma and polarization of macrophages and T cells towards a pro-reparative phenotype in the myocardium post-MI is a valid strategy for reducing infarct size and damage after myocardial injury. Our previous studies showed that cortical bone stem cells (CBSCs) possess reparative effects after ICI. In our current study, we have identified that the beneficial effects of CBSCs appear to be mediated by miRNA in their extracellular vesicles (CBSC-EV). Our studies showed that CBSC-EV treated animals demonstrated reduced scar size, attenuated structural remodeling, and improved cardiac function versus saline treated animals. These effects were linked to the alteration of immune response, with significantly altered cytokine levels in plasma, and polarization of macrophages and T cells towards a pro-reparative phenotype in the myocardium post-MI. Our detailed in vitro studies demonstrated that CBSC-EV are enriched in miR-182/183 that mediates the pro-reparative polarization and metabolic reprogramming in macrophages, including enhanced OXPHOS rate and reduced ROS, via Ras p21 protein activator 1 (RASA1) axis under Lipopolysaccharides (LPS) stimulation. In summary, CBSC-EV deliver unique molecular cargoes, such as enriched miR-182/183, that modulate the immune response after ICI by regulating macrophage polarization and metabolic reprogramming to enhance repair.

Zebrafish: A smart tool for heart disease research

The increasing prevalence of heart disease poses a significant threat to human survival and safety. However, the current treatments available for heart disease are quite limited. Therefore, it is of great importance to utilize suitable animal models that can accurately simulate the physiological characteristics of heart disease. This would help improve our understanding of this disease and aid in the development of new treatment methods and drugs. Zebrafish hearts not only exhibit similarities to mammalian hearts, but they also share ~70% of homologous genes with humans. Utilizing zebrafish as an alternative to costly and time-consuming mammalian models offers numerous advantages. Zebrafish models can be easily established and maintained, and compound screening and genetic methods allow for the creation of various economical and easily controlled zebrafish and zebrafish embryonic heart disease models in a short period of time. Consequently, zebrafish have become a powerful tool for exploring the pathological mechanisms of heart disease and identifying new effective genes. In this review, we summarize recent studies on different zebrafish models of heart disease. We also describe the techniques and protocols used to develop zebrafish models of myocardial infarction, heart failure, and congenital heart disease, including surgical procedures, forward and reverse genetics, as well as drug and combination screening. This review aims to promote the utilization of zebrafish models in investigating diverse pathological mechanisms of heart disease, enhancing our knowledge and comprehension of heart disease, and offering novel insights and objectives for exploring the prevention and treatment of heart disease.

Myocardial glucose suppression may interfere with the detection of inflammatory cells with FDG-PET as suggested in a canine model of myocardial infarction

BACKGROUND

After myocardial infarction, fibrosis and an ongoing dysregulated inflammatory response have been shown to lead to adverse cardiac remodeling. FDG PET is an imaging modality sensitive to inflammation as long as suppression protocols are observed while gadolinium enhanced MRI can be used to determine extracellular volume (ECV), a measure of fibrosis. In patients, glucose suppression is achieved variously through a high fat diet, fasting and injection of heparin. To emulate this process in canines, a heparin injection and lipid infusion are used, leading to similar fatty acids in the blood. The aim of this study was to examine the effect of glucose suppression on the uptake of FDG in the infarcted myocardial tissue and also on the determination of ECV in both the infarcted tissue and in the myocardium remote to the zone of infarction during a long constant infusion of FDG and Gd-DTPA.

RESULTS

Extracellular volume was affected neither by suppression nor the length of the constant infusion in remote and infarcted tissue. Metabolic rate of glucose in infarcted tissue decreased during and after suppression of glucose uptake by lipid infusion and heparin injection. An increase in fibrosis and inflammatory cells was found in the center of the infarct as compared to remote tissue.

CONCLUSION

The decrease in the metabolic rate of glucose in the infarcted tissue suggests that inflammatory cells may be affected by glucose suppression through heparin injection and lipid infusion.

Role of aldosterone in mid- and long-term left ventricular remodelling after acute myocardial infarction: The REMI study

AIMS

Whether aldosterone levels after myocardial infarction (MI) are associated with mid- and long-term left ventricular (LV) remodelling in the era of systematic use of renin-angiotensin system inhibitors is uncertain. We prospectively investigated the relationship between aldosterone levels and mid- and long-term LV remodelling in patients with acute MI.

METHODS AND RESULTS

Plasma aldosterone was measured in 119 patients successfully treated by primary percutaneous coronary angioplasty for a first acute ST-elevation MI (STEMI) 2-4 days after the acute event. LV volumes were assessed by cardiac magnetic resonance (CMR) and transthoracic echocardiography (TTE) in the same timeframe and 6 months later. LV assessment was repeated by TTE 3-9 years after MI (n = 80). The median aldosterone level at baseline was 23.1 [16.8; 33.1] pg/ml. In the multivariable model, higher post-MI aldosterone concentration was significantly associated with more pronounced increase in LV end-diastolic volume index (TTE: β ± standard error [SE]: 0.113 ± 0.046, p = 0.015; CMR: β ± SE: 0.098 ± 0.040, p = 0.015) and LV end-systolic volume index (TTE: β ± SE: 0.083 ± 0.030, p = 0.008; CMR: β ± SE: 0.064 ± 0.032, p = 0.048) at 6-month follow-up, regardless of the method of assessment. This result was consistent also in patients with a LV ejection fraction (LVEF) >40%. The association between baseline plasma aldosterone and adverse LV remodelling did not persist at the 3-9-year follow-up evaluation.

CONCLUSION

Aldosterone concentration in the acute phase was associated with adverse LV remodelling in the medium term, even in the subgroup of patients with LVEF >40%, suggesting a potential role of the mineralocorticoid system in post-MI adverse remodelling. Plasma aldosterone was no longer associated with LV remodelling in the long term (NCT01109225).

Short and Long-Term Prognostic Significance of Galectin-3 in Patients with ST-Elevation Myocardial Infarction Undergoing Primary Percutaneous Coronary Intervention

This study evaluated the short and long-term prognostic value of galectin-3 in patients with ST-segment elevation myocardial infarction (STEMI) who underwent primary percutaneous coronary intervention (PCI). Patients (n = 143) were admitted with STEMI and followed up for 2 years. The study population was divided into high and low galectin-3 groups based on the admission median value of serum galectin-3. Primary clinical outcomes consisted of cardiovascular (CV) mortality, non-fatal reinfarction, stroke, and target vessel revascularization (TVR). CV events were recorded in hospital and at 1 and 2 years. The primary clinical outcomes (in-hospital, 1 year and 2 year) were significantly higher in the high galectin-3 group. (P = .008, P = .004, P = .002, respectively). High galectin-3 levels were also associated with heart failure development and re-hospitalization at both 1 year (P = .029, P = .009, respectively) and 2 years (P = .019, P = .036, respectively). According to Cox multivariate analysis, left ventricular ejection fraction (LVEF) was an independent predictor of 2-year cardiovascular mortality (P = .009), whereas galectin-3 was not (P = .291). Although high galectin-3 levels were not independent predictors of long-term CV mortality in patients with acute STEMI who underwent primary PCI, it was associated with short-term and long-term development of adverse CV events, heart failure, and re-hospitalization.

Efficacy and safety of catheter ablation as first-line therapy for the management of ventricular tachycardia

BACKGROUND

Ventricular tachycardia (VT) is associated with significantly increased morbidity and mortality. Catheter ablation (CA) in line with an implantable cardioverter-defibrillator (ICD) is highly effective in VT management; however, it is unknown if CA should be considered as first-line therapy. The aim of this study is to verify the efficacy and safety of CA as first-line therapy for the first VT presentation (as adjunctive to ICD insertion), compared to initial ICD insertion and anti-arrhythmic drug (AAD) therapy.

METHODS

Data from patients with the first presentation for VT from January 2017 to January 2021 was reviewed. Patients were classified as "ablation first" vs "ICD first" groups and compared the clinical outcomes between groups.

RESULTS

One hundred and eighty-four consecutive patients presented with VT; 34 underwent CA as first-line therapy prior to ICD insertion, and 150 had ICD insertion/AAD therapy as first-line. During the median follow-up of 625 days, patients who underwent CA as first-line therapy had significantly higher ventricular arrhythmia (VA)-free survival (91% vs 59%, log-rank P = 0.002) and composite of VA recurrence, cardiovascular hospitalization, transplant, and death (84% vs 54%, log-rank P = 0.01) compared to those who did not undergo CA. Multivariate analysis revealed that first-line CA was the only protective predictor of VA recurrence (hazard ratio (HR) 0.20, P = 0.003). There were 3 (9%) peri-procedural complications with no peri-procedural deaths.

CONCLUSION

Real-world data supports the efficacy and safety of CA as first-line therapy at the time of the first VT hospitalization, compared to the initial ICD implant and AAD therapy.

Imaging Predictors of Left Ventricular Functional Recovery after Reperfusion Therapy of ST-Elevation Myocardial Infarction Assessed by Cardiac Magnetic Resonance

BACKGROUND

Left ventricular global longitudinal strain (LV GLS) is a superior predictor of adverse cardiac events in patients with myocardial infarction and heart failure. We investigated the ability of morphological features of infarcted myocardium to detect acute left ventricular (LV) dysfunction and predict LV functional recovery after three months in patients with acute ST-segment elevation myocardial infarction (STEMI).

METHODS

Sixty-six STEMI patients were included in the C-reactive protein (CRP) apheresis in Acute Myocardial Infarction Study (CAMI-1). LV ejection fraction (LVEF), LV GLS, LV global circumferential strain (LV GCS), infarct size (IS), area-at-risk (AAR), and myocardial salvage index (MSI) were assessed by CMR 5 ± 3 days (baseline) and 12 ± 2 weeks after (follow-up) the diagnosis of first acute STEMI.

RESULTS

Significant changes in myocardial injury parameters were identified after 12 weeks of STEMI diagnosis. IS decreased from 23.59 ± 11.69% at baseline to 18.29 ± 8.32% at follow-up (p < 0.001). AAR and MVO also significantly reduced after 12 weeks. At baseline, there were reasonably moderate correlations between IS and LVEF (r = -0.479, p < 0.001), LV GLS (r = 0.441, p < 0.001) and LV GCS (r = 0.396, p = 0.001) as well as between AAR and LVEF (r = -0.430, p = 0.003), LV GLS (r = 0.501, p < 0.001) and weak with LV GCS (r = 0.342, p = 0.020). At follow-up, only MSI and change in LV GCS over time showed a weak but significant correlation (r = -0.347, p = 0.021). Patients with larger AAR at baseline improved more in LVEF (p = 0.019) and LV GLS (p = 0.020) but not in LV GCS.

CONCLUSION

The CMR tissue characteristics of myocardial injury correlate with the magnitude of LV dysfunction during the acute stage of STEMI. AAR predicts improvement in LVEF and LV GLS, while MSI is a sensitive marker of LV GCS recovery at three months follow-up after STEMI.

Mechanism of fibroblast growth factor 21 in cardiac remodeling

Cardiac remodeling is a basic pathological process that enables the progression of multiple cardiac diseases to heart failure. Fibroblast growth factor 21 is considered a regulator in maintaining energy homeostasis and shows a positive role in preventing damage caused by cardiac diseases. This review mainly summarizes the effects and related mechanisms of fibroblast growth factor 21 on pathological processes associated with cardiac remodeling, based on a variety of cells of myocardial tissue. The possibility of Fibroblast growth factor 21 as a promising treatment for the cardiac remodeling process will also be discussed.

Disrupting circadian control of peripheral myogenic reactivity mitigates cardiac injury following myocardial infarction

AIMS

Circadian rhythms orchestrate important functions in the cardiovascular system: the contribution of microvascular rhythms to cardiovascular disease progression/severity is unknown. This study hypothesized that (i) myogenic reactivity in skeletal muscle resistance arteries is rhythmic and (ii) disrupting this rhythmicity would alter cardiac injury post-myocardial infarction (MI).

METHODS AND RESULTS

Cremaster skeletal muscle resistance arteries were isolated and assessed using standard pressure myography. Circadian rhythmicity was globally disrupted with the ClockΔ19/Δ19 mutation or discretely through smooth muscle cell-specific Bmal1 deletion (Sm-Bmal1 KO). Cardiac structure and function were determined by echocardiographic, hemodynamic and histological assessments. Myogenic reactivity in cremaster muscle resistance arteries is rhythmic. This rhythm is putatively mediated by the circadian modulation of a mechanosensitive signalosome incorporating tumour necrosis factor and casein kinase 1. Following left anterior descending coronary artery ligation, myogenic responsiveness is locked at the circadian maximum, although circadian molecular clock gene expression cycles normally. Disrupting the molecular clock abolishes myogenic rhythmicity: myogenic tone is suspended at the circadian minimum and is no longer augmented by MI. The reduced myogenic tone in ClockΔ19/Δ19 mice and Sm-Bmal1 KO mice associates with reduced total peripheral resistance (TPR), improved cardiac function and reduced infarct expansion post-MI.

CONCLUSIONS

Augmented microvascular constriction aggravates cardiac injury post-MI. Following MI, skeletal muscle resistance artery myogenic reactivity increases specifically within the rest phase, when TPR would normally decline. Disrupting the circadian clock interrupts the MI-induced augmentation in myogenic reactivity: therapeutics targeting the molecular clock, therefore, may be useful for improving MI outcomes.

Contractile Adaptation of the Left Ventricle Post-myocardial Infarction: Predictions by Rodent-Specific Computational Modeling

Myocardial infarction (MI) results in cardiac myocyte death and the formation of a fibrotic scar in the left ventricular free wall (LVFW). Following an acute MI, LVFW remodeling takes place consisting of several alterations in the structure and properties of cellular and extracellular components with a heterogeneous pattern across the LVFW. The normal function of the heart is strongly influenced by the passive and active biomechanical behavior of the LVFW, and progressive myocardial structural remodeling can have a detrimental effect on both diastolic and systolic functions of the LV leading to heart failure. Despite important advances in understanding LVFW passive remodeling in the setting of MI, heterogeneous remodeling in the LVFW active properties and its relationship to organ-level LV function remain understudied. To address these gaps, we developed high-fidelity finite-element (FE) rodent computational cardiac models (RCCMs) of MI using extensive datasets from MI rat hearts representing the heart remodeling from one-week (1-wk) to four-week (4-wk) post-MI timepoints. The rat-specific models (n = 2 for each timepoint) integrate detailed imaging data of the heart geometry, myocardial fiber architecture, and infarct zone determined using late gadolinium enhancement prior to terminal measurements. The computational models predicted a significantly higher level of active tension in remote myocardium in early post-MI hearts (1-wk post-MI) followed by a return to near the control level in late-stage MI (3- and 4-wk post-MI). The late-stage MI rats showed smaller myofiber ranges in the remote region and in-silico experiments using RCCMs suggested that the smaller fiber helicity is consistent with lower contractile forces needed to meet the measured ejection fractions in late-stage MI. In contrast, in-silico experiments predicted that collagen fiber transmural orientation in the infarct region has little influence on organ-level function. In addition, our MI RCCMs indicated that reduced and potentially positive circumferential strains in the infarct region at end-systole can be used to infer information about the time-varying properties of the infarct region. The detailed description of regional passive and active remodeling patterns can complement and enhance the traditional measures of LV anatomy and function that often lead to a gross and limited assessment of cardiac performance. The translation and implementation of our model in patient-specific organ-level simulations offer to advance the investigation of individualized prognosis and intervention for MI.

A review on experimental surgical models and anesthetic protocols of heart failure in rats

Heart failure (HF) is a serious health and economic burden worldwide, and its prevalence is continuously increasing. Current medications effectively moderate the progression of symptoms, and there is a need for novel preventative and reparative treatments. The development of novel HF treatments requires the testing of potential therapeutic procedures in appropriate animal models of HF. During the past decades, murine models have been extensively used in fundamental and translational research studies to better understand the pathophysiological mechanisms of HF and develop more effective methods to prevent and control congestive HF. Proper surgical approaches and anesthetic protocols are the first steps in creating these models, and each successful approach requires a proper anesthetic protocol that maintains good recovery and high survival rates after surgery. However, each protocol may have shortcomings that limit the study's outcomes. In addition, the ethical regulations of animal welfare in certain countries prohibit the use of specific anesthetic agents, which are widely used to establish animal models. This review summarizes the most common and recent surgical models of HF and the anesthetic protocols used in rat models. We will highlight the surgical approach of each model, the use of anesthesia, and the limitations of the model in the study of the pathophysiology and therapeutic basis of common cardiovascular diseases.

Left Ventricular Hypertrophy and Ventricular Tachyarrhythmia: The Role of Biomarkers

Left ventricular hypertrophy (LVH) refers to a complex rebuilding of the left ventricle that can gradually lead to serious complications-heart failure and life-threatening ventricular arrhythmias. LVH is defined as an increase in the size of the left ventricle (i.e., anatomically), therefore the basic diagnosis detecting the increase in the LV size is the domain of imaging methods such as echocardiography and cardiac magnetic resonance. However, to evaluate the functional status indicating the gradual deterioration of the left ventricular myocardium, additional methods are available approaching the complex process of hypertrophic remodeling. The novel molecular and genetic biomarkers provide insights on the underlying processes, representing a potential basis for targeted therapy. This review summarizes the spectrum of the main biomarkers employed in the LVH valuation.

Stomatin-like protein 2 deficiency exacerbates adverse cardiac remodeling

Myocardial fibrosis, oxidative stress, and autophagy both play key roles in the progression of adverse cardiac remodeling. Stomatin-like protein 2 (SLP-2) is closely related to mitochondrial function, but little is known about its role and mechanism in cardiac remodeling. We developed doxorubicin (Dox), angiotensin (Ang) II, and myocardial ischemia-reperfusion (I/R) injury induced cardiac remodeling model and Dox treated H9C2 cell injury model using SLP-2 knockout (SLP-2^-/-) mice and H9C2 cells with low SLP-2 expression. We first examined cardiac functional and structural changes as well as levels of oxidative stress, apoptosis and autophagy. We found that SLP-2 deficiency leads to decreased cardiac function and promotes myocardial fibrosis. After Dox and Ang II treatment, SLP-2 deficiency further aggravated myocardial fibrosis, increased myocardial oxidative stress and apoptosis, and activated autophagy by inhibiting PI3K-Akt-mTOR signaling pathway, ultimately exacerbating adverse cardiac remodeling. Similarly, SLP-2 deficiency further exacerbates adverse cardiac remodeling after myocardial I/R injury. Moreover, we extracted cardiomyocyte mitochondria for proteomic analysis, suggesting that SLP-2 deficiency may be involved in myocardial I/R injury induced adverse cardiac remodeling by influencing ubiquitination of intramitochondrial proteins. In addition, the oxidative stress, apoptosis and autophagy levels of H9C2 cells with low SLP-2 expression were further enhanced, and the PI3K-Akt-mTOR signaling pathway was further inhibited under Dox stimulation. Our results suggest that SLP-2 deficiency promotes myocardial fibrosis, disrupts normal mitochondrial function, overactivates autophagy via PI3K-Akt-mTOR signaling pathway, affects the level of ubiquitination, leads to irreversible myocardial damage, and ultimately exacerbates adverse cardiac remodeling.

Pathophysiology of LV Remodeling Following STEMI: A Longitudinal Diffusion Tensor CMR Study

BACKGROUND

Adverse LV remodeling post-ST-segment elevation myocardial infarction (STEMI) is associated with a poor prognosis, but the underlying mechanisms are not fully understood. Diffusion tensor (DT)-cardiac magnetic resonance (CMR) allows in vivo characterization of myocardial architecture and provides unique mechanistic insight into pathophysiologic changes following myocardial infarction.

OBJECTIVES

This study evaluated the potential associations between DT-CMR performed soon after STEMI and long-term adverse left ventricular (LV) remodeling following STEMI.

METHODS

A total of 100 patients with STEMI underwent CMR at 5 days and 12 months post-reperfusion. The protocol included DT-CMR for assessing fractional anisotropy (FA), secondary eigenvector angle (E2A) and helix angle (HA), cine imaging for assessing LV volumes, and late gadolinium enhancement for calculating infarct and microvascular obstruction size. Adverse remodeling was defined as a 20% increase in LV end-diastolic volume at 12 months.

RESULTS

A total of 32 patients experienced adverse remodeling at 12 months. Compared with patients without adverse remodeling, they had lower FA (0.23 ± 0.03 vs 0.27 ± 0.04; P < 0.001), lower E2A (37 ± 6° vs 51 ± 7°; P < 0.001), and, on HA maps, a lower proportion of myocytes with right-handed orientation (RHM) (8% ± 5% vs 17% ± 9%; P < 0.001) in their acutely infarcted myocardium. On multivariable logistic regression analysis, infarct FA (odds ratio [OR]: <0.01; P = 0.014) and E2A (OR: 0.77; P = 0.001) were independent predictors of adverse LV remodeling after adjusting for left ventricular ejection fraction (LVEF) and infarct size. There were no significant changes in infarct FA, E2A, or RHM between the 2 scans.

CONCLUSIONS

Extensive cardiomyocyte disorganization (evidenced by low FA), acute loss of sheetlet angularity (evidenced by low E2A), and a greater loss of organization among cardiomyocytes with RHM, corresponding to the subendocardium, can be detected within 5 days post-STEMI. These changes persist post-injury, and low FA and E2A are independently associated with long-term adverse remodeling.

Non-Coding RNAs in Cell-to-Cell Communication: Exploiting Physiological Mechanisms as Therapeutic Targets in Cardiovascular Pathologies

Cardiovascular disease, the leading cause of death worldwide, has been characterized at the molecular level by alterations in gene expression that contribute to the etiology of the disease. Such alterations have been shown to play a critical role in the development of atherosclerosis, cardiac remodeling, and age-related heart failure. Although much is now known about the cellular and molecular mechanisms in this context, the role of epigenetics in the onset of cardiovascular disease remains unclear. Epigenetics, a complex network of mechanisms that regulate gene expression independently of changes to the DNA sequence, has been highly implicated in the loss of homeostasis and the aberrant activation of a myriad of cellular pathways. More specifically, non-coding RNAs have been gaining much attention as epigenetic regulators of various pathologies. In this review, we will provide an overview of the ncRNAs involved in cell-to-cell communication in cardiovascular disease, namely atherosclerosis, cardiac remodeling, and cardiac ageing, and the potential use of epigenetic drugs as novel therapeutic targets.

Venoarterial extracorporeal membrane oxygenation improves survival in a rat model of acute myocardial infarction

BACKGROUND

Venoarterial extracorporeal membrane oxygenation (VA-ECMO) has been widely used in high-risk acute myocardial infarction (AMI) patients with promising outcomes. However, the underlying molecular mechanisms remain unknown and a VA-ECMO animal model has not yet been established. The purpose of this study was to establish a VA-ECMO model in AMI rats and evaluate long-term cardiac function.

METHODS

We first established AMI in 20 Sprague-Dawley (SD) rats by ligating the left anterior descending coronary artery, while five rats underwent a thoracotomy to form the sham group. VA-ECMO was established after 30mins of AMI in 10 rats through the right jugular vein for venous drainage and right femoral artery for arterial infusion. Arterial blood pressure was monitored using a catheter in the left femoral artery, blood gas parameters were measured using a blood gas analyzer, while myocardial enzymes were detected using an ELISA Kit. Cardiac function was assessed through echocardiography on day 15. Masson staining and Western Blot were used for evaluating myocardial fibrosis, while histological injury was evaluated using hematoxylin and eosin staining.

RESULTS

VA-ECMO support stabilized blood pressure, decreased the levels of myocardial enzymes including cTnI, cTnT, CK-MB, and was associated with a higher survival rate. In the long term, the VA-ECMO group showed improved cardiac function, significantly increased EF and FS but significantly decreased EDV and ESV compared to the AMI group. Furthermore, VA-ECMO significantly alleviated pathological damage and myocardial fibrosis.

CONCLUSION

We established an economical, reliable, and reproducible VA-ECMO animal model in AMI rats, and demonstrated that VA-ECMO support prevents deteriorated cardiac function.

A novel risk stratification model for STEMI after primary PCI: global longitudinal strain and deep neural network assisted myocardial contrast echocardiography quantitative analysis

Background

In ST-segment elevation myocardial infarction (STEMI) with the restoration of TIMI 3 flow by percutaneous coronary intervention (PCI), visually defined microvascular obstruction (MVO) was shown to be the predictor of poor prognosis, but not an ideal risk stratification method. We intend to introduce deep neural network (DNN) assisted myocardial contrast echocardiography (MCE) quantitative analysis and propose a better risk stratification model.

Methods

194 STEMI patients with successful primary PCI with at least 6 months follow-up were included. MCE was performed within 48 h after PCI. The major adverse cardiovascular events (MACE) were defined as cardiac death, congestive heart failure, reinfarction, stroke, and recurrent angina. The perfusion parameters were derived from a DNN-based myocardial segmentation framework. Three patterns of visual microvascular perfusion (MVP) qualitative analysis: normal, delay, and MVO. Clinical markers and imaging features, including global longitudinal strain (GLS) were analyzed. A calculator for risk was constructed and validated with bootstrap resampling.

Results

The time-cost for processing 7,403 MCE frames is 773 s. The correlation coefficients of microvascular blood flow (MBF) were 0.99 to 0.97 for intra-observer and inter-observer variability. 38 patients met MACE in 6-month follow-up. We proposed A risk prediction model based on MBF [HR: 0.93 (0.91-0.95)] in culprit lesion areas and GLS [HR: 0.80 (0.73-0.88)]. At the best risk threshold of 40%, the AUC was 0.95 (sensitivity: 0.84, specificity: 0.94), better than visual MVP method (AUC: 0.70, Sensitivity: 0.89, Specificity: 0.40, IDI: -0.49). The Kaplan-Meier curves showed that the proposed risk prediction model allowed for better risk stratification.

Conclusion

The MBF + GLS model allowed more accurate risk stratification of STEMI after PCI than visual qualitative analysis. The DNN-assisted MCE quantitative analysis is an objective, efficient and reproducible method to evaluate microvascular perfusion.

[68Ga]Ga-DOTA-FAPI-04 PET/MR in patients with acute myocardial infarction: potential role of predicting left ventricular remodeling

PURPOSE

To assess predictive value of ⁶⁸Ga-labeled fibroblast activation protein inhibitor-04 ([⁶⁸Ga]Ga-DOTA-FAPI-04) PET/MR for late left ventricular (LV) remodeling in patients with ST-segment elevated myocardial infarction (STEMI).

METHODS

Twenty-six patients with STEMI were included in the study. [⁶⁸Ga]Ga-DOTA-FAPI-04 PET/MR was performed at baseline and at average 12 months after STEMI. LV remodeling was defined as >10% increase in LV end-systolic volume (LVESV) from baseline to 12 months.

RESULTS

The LV remodeling group demonstrated higher [⁶⁸Ga]Ga-DOTA-FAPI-04 uptake volume (UV) at baseline than the non-LV remodeling group (p < 0.001). [⁶⁸Ga]Ga-DOTA-FAPI-04 UV at baseline was a significant predictor (OR = 1.048, p = 0.011) for LV remodeling at 12 months after STEMI. Compared to clinical information, MR imaging and cardiac function parameters at baseline, [⁶⁸Ga]Ga-DOTA-FAPI-04 UV demonstrated better predictive ability (AUC = 0.938, p < 0.001) for late LV remodeling, with sensitivity of 100.0% and specificity of 81.3%.

CONCLUSIONS

[⁶⁸Ga]Ga-DOTA-FAPI-04 PET/MR is an effective tool to non-invasively quantify myocardial fibroblasts activation, and baseline [⁶⁸Ga]Ga-DOTA-FAPI-04 UV may have potential predictive value for late LV remodeling.

A myocardial infarct border-zone-on-a-chip demonstrates distinct regulation of cardiac tissue function by an oxygen gradient

After a myocardial infarction, the boundary between the injured, hypoxic tissue and the adjacent viable, normoxic tissue, known as the border zone, is characterized by an oxygen gradient. Yet, the impact of an oxygen gradient on cardiac tissue function is poorly understood, largely due to limitations of existing experimental models. Here, we engineered a microphysiological system to controllably expose engineered cardiac tissue to an oxygen gradient that mimics the border zone and measured the effects of the gradient on electromechanical function and the transcriptome. The gradient delayed calcium release, reuptake, and propagation; decreased diastolic and peak systolic stress; and increased expression of inflammatory cascades that are hallmarks of myocardial infarction. These changes were distinct from those observed in tissues exposed to uniform normoxia or hypoxia, demonstrating distinct regulation of cardiac tissue phenotypes by an oxygen gradient. Our border-zone-on-a-chip model advances functional and mechanistic insight into oxygen-dependent cardiac tissue pathophysiology.