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Background: RBPs (RNA-binding proteins) perform indispensable functions in the post-transcriptional regulation of gene expression. Numerous RBPs have been implicated in cardiac development or physiology based on gene knockout studies and the identification of pathogenic RBP gene mutations in monogenic heart disorders. The discovery and characterization of additional RBPs performing indispensable functions in the heart will advance basic and translational cardiovascular research. Methods: We performed a differential expression screen in zebrafish embryos to identify genes enriched in nkx2.5 -positive cardiomyocytes or cardiopharyngeal progenitors compared to nkx2.5 -negative cells from the same embryos. We investigated the myocardial-enriched gene RNA-binding protein with multiple splicing (variants) 2 [ RBPMS2 )] by generating and characterizing rbpms2 knockout zebrafish and human cardiomyocytes derived from RBPMS2 -deficient induced pluripotent stem cells. Results: We identified 1848 genes enriched in the nkx2.5 -positive population. Among the most highly enriched genes, most with well-established functions in the heart, we discovered the ohnologs rbpms2a and rbpms2b , which encode an evolutionarily conserved RBP. Rbpms2 localizes selectively to cardiomyocytes during zebrafish heart development and strong cardiomyocyte expression persists into adulthood. Rbpms2-deficient embryos suffer from early cardiac dysfunction characterized by reduced ejection fraction. The functional deficit is accompanied by myofibril disarray, altered calcium handling, and differential alternative splicing events in mutant cardiomyocytes. These phenotypes are also observed in RBPMS2-deficient human cardiomyocytes, indicative of conserved molecular and cellular function. RNA-sequencing and comparative analysis of genes mis-spliced in RBPMS2-deficient zebrafish and human cardiomyocytes uncovered a conserved network of 29 ortholog pairs that require RBPMS2 for alternative splicing regulation, including RBFOX2, SLC8A1 , and MYBPC3 . Conclusions: Our study identifies RBPMS2 as a conserved regulator of alternative splicing, myofibrillar organization, and calcium handling in zebrafish and human cardiomyocytes.

Prolonged and intense stress can exceed the body's normal self-regulation and limited compensatory and repair capacity, resulting in pathological damage to the body. In this study, we established a rat stress myocardial injury (SMI) model to explore the protective effect of melatonin (MLT) on SMI and its possible mechanisms of action. Adult female Sprague Dawley (SD) rats were randomly divided into 5 groups: blank control group (NC), SMI group, MLT low-dose group, MLT medium-dose group, and MLT high-dose group, and 10 rats in each group were used to establish a SMI model by the water immersion restraint method. We observed the changes in body weight and tail vein glucose of each group. Serum levels of corticosterone (Cort), creatine kinase isoenzyme (CK-MB), and Troponin Ⅰ (Tn-Ⅰ) and activity of lactic acid dehydrogenase were measured by ELISA. Transcriptome sequencing was used to find differentially expressed genes in the control and model groups, and the results were verified by real-time fluorescence quantitative polymerase chain reaction (RT-qPCR). HE staining was used to visualize the pathological changes in the heart tissue of each group, and Western blot was used to study the differences in protein expression in the cardiomyocytes of each group to further corroborate the results. The body weight growth rate of rats in the SMI group was significantly lower than that of the NC group ( P0.01), and the body weight growth rate of rats in the MLT high-dose group was significantly higher than that of the SMI group ( P0.05) with no significant difference compared with the NC group rats. The mean blood glucose of rats in the SMI group was significantly higher compared with the NC group ( P0.001), while the mean blood glucose of rats in the MLT administration groups was dose-dependently reduced compared with the SMI group. By RNA-seq and bioinformatics tools such as KEGG and Gene ontology, we found that the circadian clock-related genes Ciart , Arnt1 , Per1 , and Dbp were significantly downregulated in the SMI group during water immersion stress, and differentially expressed genes were enriched in the p38MAPK signaling pathway and p53 signaling pathway. Moreover, genes related to inflammation and apoptosis were differentially expressed. ELISA results showed that Cort, CK-MB, and Tn-Ⅰ levels were significantly higher in the SMI group compared with the NC group ( P0.01) and melatonin reduced the levels of Cort, CK-MB, and Tn-Ⅰ and decreased lactic acid dehydrogenase activity in rat serum. HE staining results showed that melatonin could attenuate stress-generated myocardial injury. Western blot showed that melatonin reduced the expression of p38MAPK, p53, Bax, and caspase-3 and increased the expression of Bcl-2 protein in rat heart. Melatonin can inhibit myocardial injury caused by water immersion, and its mechanism of action may be related to the regulation of the expression of circadian clock genes such as Ciart , Arnt1 , Per1 , and Dbp ; the inhibition of the expression of proapoptotic proteins such as p38MAPK, p53, Bax, and caspase-3; and the increase of the expression of Bcl-2 antiapoptotic protein.

Adrenergic receptors (ARs) are G protein-coupled receptors that are stimulated by catecholamines to induce a wide array of physiological effects across tissue types. Both α1- and β-ARs are found on cardiomyocytes and regulate cardiac contractility and hypertrophy through diverse molecular pathways. Acute activation of cardiomyocyte β-ARs increases heart rate and contractility as an adaptive stress response. However, chronic β-AR stimulation contributes to the pathobiology of heart failure. By contrast, mounting evidence suggests that α1-ARs serve protective functions that may mitigate the deleterious effects of chronic β-AR activation. Here, we will review recent studies demonstrating that α1- and β-ARs differentially regulate mitochondrial biogenesis and dynamics, mitochondrial calcium handling, and oxidative phosphorylation in cardiomyocytes. We will identify potential mechanisms of these actions and focus on the implications of these findings for the modulation of contractile function in the uninjured and failing heart. Collectively, we hope to elucidate important physiological processes through which these well-studied and clinically relevant receptors stimulate and fuel cardiac contraction to contribute to myocardial health and disease.

Background: The prognostic significance of focal and diffuse myocardial fibrosis in patients with cardiovascular risk factors is unclear. Methods: REMODEL (Response of the Myocardium to Hypertrophic Conditions in the Adult Population) is an observational cohort of asymptomatic patients with essential hypertension. All participants underwent cardiovascular magnetic resonance to assess for myocardial fibrosis: nonischemic late gadolinium enhancement (LGE), native myocardial T1, postcontrast myocardial T1, extracellular volume fraction including/excluding LGE regions, interstitial volume (extracellular volume×myocardial volume), and interstitial/myocyte ratio. Primary outcome was a composite of first occurrence acute coronary syndrome, heart failure hospitalization, strokes, and cardiovascular mortality. Patients were recruited from February 2016 and followed until June 2021. Results: Of the 786 patients with hypertension (58±11 years; 39% women; systolic blood pressure, 130±14 mm Hg), 145 (18%) had nonischemic LGE. Patients with nonischemic LGE were more likely to be men, have diabetes, be current smokers, and have higher blood pressure ( P 2 ; P P P P =0.002) demonstrated independent association with primary outcome. Conclusions: In patients with hypertension, myocardial fibrosis on cardiovascular magnetic resonance is associated with adverse cardiac remodeling and outcomes.

Homeodomain-interacting protein kinase-2 (HIPK2), a member of an evolutionary conserved family of serine/threonine kinases, has been observed to be involved in the pathogenesis of fibrotic diseases. However, its role in cardiac fibrosis remains unclear. In this study, we assessed the effect of HIPK2 on cardiac fibroblasts (CFs) in response to angiotensin II (Ang II) stimulation. The results indicated that HIPK2 expression was significantly increased in Ang II-induced CFs in a dose-dependent manner. Then, HIPK2 was knocked down in CFs to evaluate the roles of HIPK2. Knockdown of HIPK2 suppressed cell proliferation and migration in Ang II-induced CFs. The Ang II-caused increase in expression of α-smooth muscle actin, a hallmark of myofibroblast differentiation, was decreased by knockdown of HIPK2. HIPK2 knockdown also reduced extracellular matrix production including type I collagen and connective tissue growth factor. Furthermore, knockdown of HIPK2 blocked the activation of TGF-β1/Smad pathway in Ang II-induced CFs. These data suggested that HIPK2 knockdown prevented the Ang II-induced activation of CFs through inhibiting TGF-β1/Smad pathway, indicating HIPK2 might be an antifibrosis target for the treatment of cardiac fibrosis.

As a muscular pump that contracts incessantly throughout life, the heart must constantly generate cellular energy to support contractile function and fuel ionic pumps to maintain electrical homeostasis. Thus, mitochondrial metabolism of multiple metabolic substrates such as fatty acids, glucose, ketones, and lactate is essential to ensuring an uninterrupted supply of ATP. Multiple metabolic pathways converge to maintain myocardial energy homeostasis. The regulation of these cardiac metabolic pathways has been intensely studied for many decades. Rapid adaptation of these pathways is essential for mediating the myocardial adaptation to stress, and dysregulation of these pathways contributes to myocardial pathophysiology as occurs in heart failure and in metabolic disorders such as diabetes. The regulation of these pathways reflects the complex interactions of cell-specific regulatory pathways, neurohumoral signals, and changes in substrate availability in the circulation. Significant advances have been made in the ability to study metabolic regulation in the heart, and animal models have played a central role in contributing to this knowledge. This review will summarize metabolic pathways in the heart and describe their contribution to maintaining myocardial contractile function in health and disease. The review will summarize lessons learned from animal models with altered systemic metabolism and those in which specific metabolic regulatory pathways have been genetically altered within the heart. The relationship between intrinsic and extrinsic regulators of cardiac metabolism and the pathophysiology of heart failure and how these have been informed by animal models will be discussed.

Selective aortic arch perfusion (SAAP) is an endovascular technique that consists of aortic occlusion with perfusion of the coronary and cerebral circulation. It been shown to facilitate return of spontaneous circulation (ROSC) after exanguination cardiac arrest (ECA), but it is not known how long arrest may last before the myocardium can no longer be durably recovered. The aim of this study is to assess the myocardial tolerance to exsanguination cardiac arrest before successful ROSC with SAAP.Male adult swine (n = 24) were anesthetized, instrumented, and hemorrhaged to arrest. Animals were randomized into three groups: 5, 10, and 15 min of cardiac arrest before resuscitation with SAAP. Following ROSC, animals were observed for 60 min in a critical care environment. Primary outcomes were ROSC, and survival at 1-h post-ROSC.Shorter cardiac arrest time was associated with higher ROSC rate and better 1-h survival. ROSC was obtained for 100% (8/8) of the 5-min ECA group, 75% (6/8) of the 10-min group, 43% (3/7) of the 15-min group (P = 0.04). One-hour post-ROSC survival was 75%, 50%, and 14% in 5-, 10-, and 15-min groups, respectively (P = 0.02). One-hour survivors in the 5-min group required less norepinephrine (1.31 mg ± 0.83 mg) compared with 10-SAAP (0.76 mg ± 0.24 mg), P = 0.008.Whole blood SAAP can accomplish ROSC at high rates even after 10 min of unsupported cardiac arrest secondary to hemorrhage, with some viability beyond to 15 min. This is promising as a tool for ECA, but requires additional optimization and clinical trials.Animal Use Protocol, IACUC: 0919015.

A 55-year-old man presented with chest tightness and lower-limb edema for 1 year. Laboratory and imaging examinations suggested cardiac amyloidosis. Both 18F-FDG and 68Ga-pentixafor PET/CT showed increased uptake in the myocardium of the left ventricle, whereas the bone marrow had diffusely mild uptake of 68Ga-pentixafor without bone destruction. 99mTc-MDP bone scintigraphy also detected extraosseous uptake in the heart, gut, kidneys, and soft tissue. The biopsy of the abdominal subcutaneous fat confirmed amyloid deposits, and the patient was finally diagnosed with primary systemic amyloidosis. This case demonstrated that cardiac amyloidosis might show increased 68Ga-pentixafor uptake in myocardium.

Myocardial fibrosis after myocardial infarction (MI) leads to heart failure, which has become an important global public health issue. One of the most important features of myocardial fibrosis is the abnormal deposition of extracellular matrix (ECM) proteins. Periostin is one of the ECM proteins. Cyclic AMP response element-binding protein 1 (CREB) is well known for its involvement in multiple signaling in myocardial fibrosis. It has been confirmed that CREB could regulate ECM proteins deposition. However, little is known about the relationship between CREB and periostin post-MI. This study aims to verify the hypothesis that CREB promotes the expression of periostin in MI-induced myocardial fibrosis. To test this hypothesis, primary rat cardiac fibroblasts were cultured and rat model of MI was established. The level of myocardial fibrosis post-MI was identified by histological staining. The expressions of CREB and periostin were detected through western blot and reverse transcription quantity polymerase chain reaction. The upregulation and downregulation of CREB and periostin were established by plasmid, small interfere RNA (siRNA), and lentivirus, respectively. High levels of CREB and periostin were found post-MI in our study. Meanwhile, the expression of periostin was decreased after CREB downregulation both in vivo and in vitro. Finally, with the treatment of pAV-CREB and si-periostin, the expressions of collagen Ⅰ and Ⅲ were attenuated. The expression of periostin was elevated post-MI and participated in MI-induced myocardial fibrosis, which was regulated through CREB. This study provides a novel idea and potential intervention target for MI-induced myocardial fibrosis.

Magnolol is a component of the bark of Magnolia officinalis, which is a traditional herbal remedy used in China. In this study, we investigated whether magnolol can reduce myocardial injury induced by renal ischemia and reperfusion (I/R).Renal I/R was elicited by a 60-minute occlusion of the bilateral renal arteries and a 24-hour reperfusion in Sprague-Dawley rats. Magnolol was administered intravenously 10 minutes before renal I/R to evaluate its effects on myocardial injury induced by renal I/R.Renal I/R significantly increased the serum levels of creatine phosphokinase (CPK), lactate dehydrogenase (LDH), and cardiac troponin I and caused myocardial damage. The terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling-positive nuclei and caspase-3 activation was significantly increased in the myocardium, indicating increase of apoptosis. Echocardiography revealed left ventricular dysfunction, as evidenced by reduction of left ventricular ejection fraction and left ventricular fractional shortening. Furthermore, serum levels of tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, and IL-6 were significantly elevated, while the IL-10 level was suppressed. However, intravenously, pretreatment with magnolol at doses of 0.003 and 0.006 mg/kg 10 minutes before renal I/R significantly prevented the increases of CPK, LDH, and cardiac troponin I levels, as well as the histological damage and the apoptosis in the myocardium. Echocardiography showed significant improvement of left ventricular function. Furthermore, the increases in TNF-α, IL-1β, and IL-6 and the decrease in IL-10 were significantly limited, while Bcl-2 was increased and Bax was decreased in the myocardium. Phosphorylation of Akt and extracellular signal-regulated kinases 1 and 2 was increased, while phosphorylation of p38 and c-Jun N-terminal kinase was reduced.Magnolol reduces myocardial injury induced by renal I/R. The underlying mechanisms for this effect might be related to modulation of the production of pro- and anti-inflammatory cytokines and the limiting of apoptosis.

We aimed to validate and test a prototype algorithm for automated dual-energy computed tomography (DECT)-based myocardial extracellular volume (ECV) assessment in patients with various cardiomyopathies.This retrospective study included healthy subjects (n=9; 61±10 y) and patients with cardiomyopathy (n=109, including a validation cohort n=60; 68±9 y; and a test cohort n=49; 69±11 y), who had previously undergone cardiac DECT. Myocardial ECV was calculated using a prototype-based fully automated algorithm and compared with manual assessment. Receiver-operating characteristic analysis was performed to test the algorithm's ability to distinguish healthy subjects and patients with cardiomyopathy.The fully automated method led to a significant reduction of postprocessing time compared with manual assessment (2.2±0.4 min and 9.4±0.7 min, respectively, P0.001). There was no significant difference in ECV between the automated and manual methods ( P =0.088). The automated method showed moderate correlation and agreement with the manual technique ( r =0.68, intraclass correlation coefficient=0.66). ECV was significantly higher in patients with cardiomyopathy compared with healthy subjects, regardless of the method used ( P0.001). In the test cohort, the automated method yielded an area under the curve of 0.98 for identifying patients with cardiomyopathies.Automated ECV estimation based on DECT showed moderate agreement with the manual method and matched with previously reported ECV values for healthy volunteers and patients with cardiomyopathy. The automatically derived ECV demonstrated an excellent diagnostic performance to discriminate between healthy and diseased myocardium, suggesting that it could be an effective initial screening tool while significantly reducing the time of assessment.

Heart failure is mainly caused by a decline in the systolic function of the heart. Long noncoding RNAs are related to cardiac diseases. This study aimed to explore the effects of long noncoding RNAs testis development related gene 1 (TDRG1) on the fibrogenesis and inflammatory response of transforming growth factor-beta1 (TGF-β1)-stimulated human cardiac fibroblasts (HCFs). Levels of proinflammatory cytokines were evaluated by enzyme-linked immunosorbent assay. Reverse-transcription quantitative polymerase chain reaction was applied to reveal the expression levels of TDRG1, miR-605-3p, and tumor necrosis factor receptor superfamily (TNFRSF21). Western blot analysis was prepared to detect protein levels of TNFRSF21 and fibrosis-related genes. Luciferase reporter assay was conducted for confirming the interaction between miR-605-3p and TDRG1/TNFRSF21. We found that TGF-β1-stimulated HCFs showed high concentrations of proinflammatory cytokines and increased protein levels of fibrosis-related genes, suggesting the dysfunctions of TGF-β1-stimulated HCFs. In addition, TDRG1 was upregulated in TGF-β1-stimulated HCFs. We found that interfering with TDRG1 alleviated dysfunctions of TGF-β1-stimulated HCFs. Moreover, TDRG1 bound with miR-605-3p. MiR-605-3p exerted the antifibrogenic and anti-inflammatory effects in TGF-β1-treated HCFs. As a target gene of miR-605-3p, TNFRSF21 reversed the antifibrogenic and anti-inflammatory effects of TDRG1 knockdown in TGF-β1-treated HCFs. Overall, our study confirmed that TDRG1 aggravates fibrogenesis and inflammatory response in TGF-β1-treated HCFs via the miR-605-3p/TNFRSF21 axis.

Background: The nuclear receptor Rev-erbα/β, a key component of the circadian clock, emerges as a drug target for heart diseases, but the function of cardiac Rev-erb has not been studied in vivo. Circadian disruption is implicated in heart diseases, but it is unknown whether cardiac molecular clock dysfunction is associated with the progression of any naturally occurring human heart diseases. Obesity paradox refers to the seemingly protective role of obesity for heart failure, but the mechanism is unclear. Methods: We generated mouse lines with cardiac-specific Rev-erbα/β knockout (KO), characterized cardiac phenotype, conducted multi-omics (RNA-sequencing, chromatin immunoprecipitation sequencing, proteomics, and metabolomics) analyses, and performed dietary and pharmacological rescue experiments to assess the time-of-the-day effects. We compared the temporal pattern of cardiac clock gene expression with the cardiac dilation severity in failing human hearts. Results: KO mice display progressive dilated cardiomyopathy and lethal heart failure. Inducible ablation of Rev-erbα/β in adult hearts causes similar phenotypes. Impaired fatty acid oxidation in the KO myocardium, in particular, in the light cycle, precedes contractile dysfunctions with a reciprocal overreliance on carbohydrate utilization, in particular, in the dark cycle. Increasing dietary lipid or sugar supply in the dark cycle does not affect cardiac dysfunctions in KO mice. However, obesity coupled with systemic insulin resistance paradoxically ameliorates cardiac dysfunctions in KO mice, associated with rescued expression of lipid oxidation genes only in the light cycle in phase with increased fatty acid availability from adipose lipolysis. Inhibition of glycolysis in the light cycle and lipid oxidation in the dark cycle, but not vice versa, ameliorate cardiac dysfunctions in KO mice. Altered temporal patterns of cardiac Rev-erb gene expression correlate with the cardiac dilation severity in human hearts with dilated cardiomyopathy. Conclusions: The study delineates temporal coordination between clock-mediated anticipation and nutrient-induced response in myocardial metabolism at multi-omics levels. The obesity paradox is attributable to increased cardiac lipid supply from adipose lipolysis in the fasting cycle due to systemic insulin resistance and adiposity. Cardiac molecular chronotypes may be involved in human dilated cardiomyopathy. Myocardial bioenergetics downstream of Rev-erb may be a chronotherapy target in treating heart failure and dilated cardiomyopathy.

Currently, normothermic ex vivo heart perfusion (NEVHP) is limited to 6-12 hours. NEVHP for 24 hours or more would allow organ treatment, assessment of organ function, and near-perfect recipient matching. We present a model of NEVHP using continuous hemofiltration (HFn) with sustained myocardial viability up to 24 hours. Twenty hearts from 6-10 kg piglets were procured and maintained on our NEVHP circuit. HFn hearts (n = 10) underwent NEVHP with HFn, whereas controls (n = 10) used NEVHP alone. All HFn vs. four controls were viable at 24 h (p = 0.004). At end perfusion, HFn hearts had higher left ventricular systolic pressure (51.5 ± 6.8 mm Hg, 38.3 ± 5.2 mm Hg, p = 0.05), lower coronary resistance (0.83 ± 0.11 mm Hg/mL/min, 1.18 ± 0.21mmHg/mL/min, plt; 0.05), and lower serum lactate levels (2.9 ± 0.4 mmol/L, 4.1 ± 0.6 mmol/L, plt; 0.0001) when compared to control hearts. HFn hearts also had less extensive myocardial damage and significantly less edema than control hearts with lower weight gain and wet-dry ratios. Using our circuit, NEVHP for 24 hours is possible with HFn and allows for preservation of myocardial function, improved tissue viability, decreased tissue edema, and less myocardial injury.

Here we provide the proof-of-concept for an unconventional and effective nanotechnology-based inhalation approach for delivery of a synthetic miRNA mimic via biocompatible and biodegradable calcium phosphate-based nanoparticles (CaPs) preferentially to cardiomyocytes without significant accumulation in other myocardial cells or organs.

Supplemental Digital Content is available in the text., Background: Many heart diseases can result in reduced pumping capacity of the heart muscle. A mismatch between ATP demand and ATP production of cardiomyocytes is one of the possible causes. Assessment of the relation between myocardial ATP production (MVATP) and cardiac workload is important for better understanding disease development and choice of nutritional or pharmacologic treatment strategies. Because there is no method for measuring MVATP in vivo, the use of physiology-based metabolic models in conjunction with protein abundance data is an attractive approach. METHOD: We developed a comprehensive kinetic model of cardiac energy metabolism (CARDIOKIN1) that recapitulates numerous experimental findings on cardiac metabolism obtained with isolated cardiomyocytes, perfused animal hearts, and in vivo studies with humans. We used the model to assess the energy status of the left ventricle of healthy participants and patients with aortic stenosis and mitral valve insufficiency. Maximal enzyme activities were individually scaled by means of protein abundances in left ventricle tissue samples. The energy status of the left ventricle was quantified by the ATP consumption at rest (MVATP[rest]), at maximal workload (MVATP[max]), and by the myocardial ATP production reserve, representing the span between MVATP(rest) and MVATP(max). Results: Compared with controls, in both groups of patients, MVATP(rest) was increased and MVATP(max) was decreased, resulting in a decreased myocardial ATP production reserve, although all patients had preserved ejection fraction. The variance of the energetic status was high, ranging from decreased to normal values. In both patient groups, the energetic status was tightly associated with mechanic energy demand. A decrease of MVATP(max) was associated with a decrease of the cardiac output, indicating that cardiac functionality and energetic performance of the ventricle are closely coupled. Conclusions: Our analysis suggests that the ATP-producing capacity of the left ventricle of patients with valvular dysfunction is generally diminished and correlates positively with mechanical energy demand and cardiac output. However, large differences exist in the energetic state of the myocardium even in patients with similar clinical or image-based markers of hypertrophy and pump function. Registration: URL: https://www.clinicaltrials.gov; Unique identifiers: NCT03172338 and NCT04068740.

Myocardial infarction is a substantial contributor to ischemic heart diseases, affecting a large number of people leading to fatal conditions worldwide. MicroRNAs (miRNAs) are explicitly emerging as excellent modulators of pathways involved in maintaining cardiomyocyte survival, repair, and regeneration. Altered expression of genes in cardiomyocytes postinfarction can lead to the disordered state of the myocardium, such as cardiac hypertrophy, ischemia-reperfusion injury, left ventricular remodeling, and cardiac fibrosis. Therapeutic targeting of miRNAs in cardiomyocytes can potentially reverse the adverse effects in the heart postinfarction. This review aims to understand the role of several miRNAs involved in the regeneration and repair of cardiomyocytes postmyocardial infarction and presents comprehensive information on the subject.

Myocardial injury after noncardiac surgery is a strong predictor of 30-day mortality and morbidity.The purpose of this study was to examine the incidence of myocardial injury in patients undergoing colorectal cancer surgery in an enhanced recovery after surgery protocol and its association with 90-day mortality and morbidity.This is a retrospective cohort study.This study was conducted at Zealand University Hospital, Denmark, between June 2015 and July 2017.Adult patients undergoing colorectal cancer surgery were included if troponin was measured at least twice during the first 7 days after surgery. The patients were followed for 90 days.Myocardial injury was defined as an elevated troponin I measurement (45 ng/L) without evidence of a nonischemic origin causing the elevation. Ninety-day mortality and complications were assessed.A total of 586 patients were included of which 42 were diagnosed with myocardial injury. Thirteen patients (2%) died within 90 days of surgery. There was no significant difference in 90-day mortality between patients with and without myocardial injury (5% (2/42) versus 2% (11/544); p = 0.24). We found a higher incidence of postoperative complications within 90 days of surgery in the myocardial injury group than in the nonmyocardial injury group (43% (18/42) versus 20% (107/544); p0.01). We found a significant difference between the myocardial injury group and nonmyocardial injury group in terms of medical complications (33% (14/42) versus 9% (50/544); p0.01) but not surgical complications (19% (8/42) versus 16% (85/544); p = 0.56). Myocardial injury was an independent predictor of postoperative complications within 90 days of surgery (adjusted OR, 2.69; 95% CI, 1.31-5.55).This study was limited by its retrospective design.Myocardial injury occurs frequently in patients undergoing colorectal cancer surgery in an enhanced recovery after surgery protocol. Patients with myocardial injury did not have a significantly higher 90-day mortality but had higher risk of 90-day postoperative complications than patients without myocardial injury. Future research should examine the prevention and treatment of myocardial injury. See Video Abstract at http://links.lww.com/DCR/B692.ANTECEDENTES:La lesión del miocardio después de una cirugía no cardíaca es un fuerte predictor de mortalidad y morbilidad a los 30 días.OBJETIVO:El propósito fue examinar la incidencia de lesión miocárdica en pacientes sometidos a cirugía de cáncer colorrectal en un protocolo de recuperación mejorada después de la cirugía y su asociación con la mortalidad y morbilidad a los 90 días.DISEÑO:Estudio de cohorte retrospectivo.AJUSTE:Realizado en el Hospital Universitario de Zelanda, Dinamarca, entre junio de 2015 y julio de 2017.PACIENTES:Se incluyeron pacientes adultos sometidos a cirugía de cáncer colorrectal, si la troponina se midió al menos dos veces durante los primeros siete días después de la cirugía. Los pacientes fueron seguidos durante 90 días.PRINCIPALES MEDIDAS DE RESULTADO:La lesión miocárdica se definió como una medición de troponina I elevada (45 ng / l) sin evidencia de una etiología no isquémica que causara la elevación. Se evaluaron la mortalidad y las complicaciones a los noventa días.RESULTADOS:Se incluyeron un total de 586 pacientes, de los cuales 42 fueron diagnosticados de lesión miocárdica. Trece pacientes (2%) murieron dentro de los 90 días posteriores a la cirugía. No hubo diferencias significativas en la mortalidad a 90 días entre los pacientes con y sin lesión del miocardio, 5% [2/42] versus 2% [11/544], p = 0,24. Encontramos una mayor incidencia de complicaciones posoperatorias dentro de los 90 días de la cirugía en el grupo de lesión miocárdica en comparación con el grupo de lesión no miocárdica, 43% [18/42] versus 20% [107/544], p0,01. Encontramos una diferencia significativa entre el grupo de lesión miocárdica y el grupo de lesión no miocárdica en términos de complicaciones médicas (33% [14/42] versus 9% [50/544]; p0,01) pero no complicaciones quirúrgicas (19% [8/42] versus 16% [85/544]; p = 0,56). La lesión miocárdica fue un predictor independiente de complicaciones posoperatorias dentro de los 90 días posteriores a la cirugía (razón de probabilidades ajustada: 2,69; intervalo de confianza del 95%: 1,31 - 5,55).LIMITACIONES:Limitado por su diseño retrospectivo.CONCLUSIÓN:La lesión del miocardio ocurre con frecuencia en pacientes sometidos a cirugía de cáncer colorrectal en un protocolo de recuperación mejorada después de la cirugía. Los pacientes con lesión miocárdica no tuvieron una mortalidad significativamente mayor a los 90 días, pero tuvieron un mayor riesgo de complicaciones posoperatorias a los 90 días en comparación con los pacientes sin lesión miocárdica. Las investigaciones futuras deben examinar la prevención y el tratamiento de la lesión miocárdica. Consulte Video Resumen en http://links.lww.com/DCR/B692.

Rationale:Timely inhibition of inflammation and initiation of resolution are important to repair injured tissues. MST1/2 (mammalian STE20-like protein kinase 1/2) acts as a regulator of macrophage-associated immune responses to bacterial infections. However, the role of MST1/2 in regulating macrophage phenotype and function in myocardial infarction (MI) remains unclear.Objective:To determine the function and underlying mechanism of macrophage MST1/2 in cardiac repair post-MI.Methods and Results:UsingLysMCre-mediatedMst1/2-deficient mice, we found that MST1 deficiency exacerbated cardiac dysfunction after MI. Single-cell RNA sequencing assay indicated that the effect was attributed to a shift of macrophage subtypes from those expressingCxcl2andCd163towardCcl2andCcl4expression. Mass spectrometry identified LTB4 (leukotriene B4) as the lipid mediator that was upregulated in the absence of MST1. We found that MST1 phosphorylated 5-LOX (5-lipoxygenase) at its T218 residue, disrupting the interaction between 5-LOX and 5-LOX-activating protein, resulting in a reduction of LTB4 production. In contrast, a 5-LOXT218Avariant showed no response to MST1. Moreover, treatment of peritoneal macrophages with LTB4 or medium conditioned byMst1-deficient macrophages resulted in highCcl2andCcl4expression and lowCxcl2andCd163expression, except when the cells were co-treated with the BLT1 (LTB4 receptor 1) antagonist CP105696. Furthermore, CP105696 ameliorated cardiac dysfunction inLysMCre-mediatedMst1/2-deficient mice and enhanced cardiac repair in wild-type mice treated with XMU-MP-1 (4-((5,10-dimethyl-6-oxo-6,10-dihydro-5H-pyrimido[5,4-b]thieno[3,2-e][1,4]diazepin-2-yl)amino)benzenesulfonamide) after MI.Conclusions:Taken together, our results demonstrate that inhibition of MST1/2 impaired post-MI repair through activating macrophage 5-LOX–LTB4–BLT1 axis.

BACKGROUND Sepsis-induced cardiomyopathy (SIC) is a major contributing factor for morbidity and mortality in sepsis. Accumulative evidence has suggested that cardiac mitochondrial oxidative phosphorylation is attenuated in sepsis, but the underlying molecular mechanisms remain incompletely understood. METHODS Adult male mice of 9-12 weeks old were subjected to sham or cecal ligation and puncture procedure. Echocardiography in vivo and Langendorff-perfused hearts were used to assess cardiac function 24 hours after the procedures. Unbiased proteomics analysis was performed to profile mitochondrial proteins in the hearts of both sham and SIC mice. Seahorse respirator technology was used to evaluate oxygen consumption in purified mitochondria. RESULTS Of the 665 mitochondrial proteins identified in the proteomics assay, 35 were altered in septic mice. The mitochondrial remodeling involved various energy metabolism pathways including subunits of the electron transport chain, fatty acid catabolism, and carbohydrate oxidative metabolism. We also identified a significant increase of pyruvate dehydrogenase (PDH) kinase 4 (PDK4) and inhibition of PDH activity in septic hearts. Furthermore, compared to sham mice, mitochondrial oxygen consumption of septic mice was significantly reduced when pyruvate was provided as a substrate. However, it was unchanged when PDH was bypassed by directly supplying the Complex I substrate NADH, or by using the Complex II substrate succinate, or using Complex IV substrate, or by providing the beta-oxidation substrate palmitoylcarnitine, neither of which require PDH for mitochondrial oxygen consumption. CONCLUSIONS These data demonstrate a broad mitochondrial protein remodeling, PDH inactivation and impaired pyruvate-fueled oxidative phosphorylation during SIC, and provide a molecular framework for further exploration.

Background: Calsequestrins (Casqs), comprising the Casq1 and Casq2 isoforms, buffer Ca 2+ and regulate its release in the sarcoplasmic reticulum of skeletal and cardiac muscle, respectively. Human inherited diseases associated with mutations in CASQ1 or CASQ2 include malignant hyperthermia/environmental heat stroke (MH/EHS) and catecholaminergic polymorphic ventricular tachycardia. However, patients with an MH/EHS event often experience arrhythmia for which the underlying mechanism remains unknown. Methods: Working hearts from conventional ( Casq1 -KO) and cardiac-specific ( Casq1 -CKO) Casq1 knockout mice were monitored in vivo and ex vivo by ECG and electric mapping, respectively. MH was induced by 2% isoflurane and treated intraperitoneally with dantrolene. Time-lapse imaging was used to monitor intracellular Ca 2+ activity in isolated mouse cardiomyocytes or neonatal rat ventricular myocytes with knockdown, overexpression, or truncation of the Casq1 gene. Conformational change in both Casqs was determined by cross-linking Western blot analysis. Results: Like patients with MH/EHS, Casq1 -KO and Casq1 -CKO mice had faster basal heart rate and ventricular tachycardia on exposure to 2% isoflurane, which could be relieved by dantrolene. Basal sinus tachycardia and ventricular ectopic electric triggering also occurred in Casq1 -KO hearts ex vivo. Accordingly, the ventricular cardiomyocytes from Casq1 -CKO mice displayed dantrolene-sensitive increased Ca 2+ waves and diastole premature Ca 2+ transients/oscillations on isoflurane. Neonatal rat ventricular myocytes with Casq1-knockdown had enhanced spontaneous Ca 2+ sparks/transients on isoflurane, whereas cells overexpressing Casq1 exhibited decreased Ca 2+ sparks/transients that were absent in cells with truncation of 9 amino acids at the C terminus of Casq1. Structural evaluation showed that most of the Casq1 protein was present as a polymer and physically interacted with ryanodine receptor-2 in the ventricular sarcoplasmic reticulum. The Casq1 isoform was also expressed in human myocardium. Mechanistically, exposure to 2% isoflurane or heating at 41 °C induced Casq1 oligomerization in mouse ventricular and skeletal muscle tissues, leading to a reduced Casq1/ryanodine receptor-2 interaction and increased ryanodine receptor-2 activity in the ventricle. Conclusions: Casq1 is expressed in the heart, where it regulates sarcoplasmic reticulum Ca 2+ release and heart rate. Casq1 deficiency independently causes MH/EHS-like ventricular arrhythmia by trigger-induced Casq1 oligomerization and a relief of its inhibitory effect on ryanodine receptor-2–mediated Ca 2+ release, thus revealing a new inherited arrhythmia and a novel mechanism for MH/EHS arrhythmogenesis.

Background: In heart transplantation, antibody-mediated rejection (AMR) is a major contributor to patient morbidity and mortality. Multiple routine endomyocardial biopsies (EMB) remain the gold standard to detect AMR, but this invasive procedure suffers from many limitations. We aimed to develop and validate an AMR risk model to improve individual risk stratification of AMR. Methods: Heart recipients from 2 referral transplant centers, Cedars-Sinai (US) and Pitié-Salpêtrière (France), were included from 2012 to 2019. Database included detailed clinical, immunologic, imaging, and histological parameters. The US cohort was randomly distributed in a derivation (2/3) and in a test set (1/3). The primary end point was biopsy-proven AMR. A mixed effect logistic regression model with a random intercept was applied to identify variables independently associated with AMR. Simulation analyzes were performed. Results: The US and French cohorts comprised a total of 1341 patients, representing 12 864 EMB. Overall, 490 AMR episodes were diagnosed (3.8% of EMB). Among the 26 potential determinants of AMR, 5 variables showed independent association: time post-transplant ( P P =0.001), circulating donor-specific anti–human leukocyte antigen antibody ( P =0.001), graft dysfunction ( P =0.004), and prior history of definite AMR ( P Conclusions: Our results support the use of the AMR risk model as a clinical decision tool to minimize the number of routine EMB after heart transplantation.

BACKGROUND: Cardiac allograft vasculopathy (CAV) is a leading cause of morbidity and mortality for heart transplant recipients. While clinical risk factors for CAV have been established, no personalized prognostic test exists to confidently identify patients at high vs. low risk of developing aggressive CAV. The aim of this investigation was to leverage computational methods for analyzing digital pathology images from routine endomyocardial biopsies (EMB) to develop a precision medicine tool for predicting CAV years before overt clinical presentation. METHODS: Clinical data from 1-year post-transplant was collected on 302 transplant recipients from the University of Pennsylvania, including 53 ‘early CAV’ patients and 249 ‘no-CAV’ controls. This data was used to generate a ‘clinical model’ (ClinCAV-Pr) for predicting future CAV development. From this cohort, n=183 archived EMBs were collected for CD31 and modified trichrome staining and then digitally scanned. These included 1-year post-transplant EMBs from 50 ‘early CAV’ patients and 82 no-CAV patients, as well as 51 EMBs from ‘disease control’ patients obtained at the time of definitive coronary angiography confirming CAV. Using biologically-inspired, hand-crafted features extracted from digitized EMBs, quantitative histologic models for differentiating no-CAV from disease controls (HistoCAV-Dx), and for predicting future CAV from 1-year post-transplant EMBs were developed (HistoCAV-Pr). The performance of histologic and clinical models for predicting future CAV (i.e. HistoCAV-Pr and ClinCAV-Pr, respectively) were compared in a held-out validation set, before being combined to assess the added predictive value of an integrated predictive model (iCAV-Pr). RESULTS: ClinCAV-Pr achieved modest performance on the independent test set, with area under the receiver operating curve (AUROC) of 0.70. The HistoCAV-Dx model for diagnosing CAV achieved excellent discrimination, with an AUROC of 0.91, while HistoCAV-Pr model for predicting CAV achieved good performance with an AUROC of 0.80. The integrated iCAV-Pr model achieved excellent predictive performance, with an AUROC of 0.93 on the held-out test set. CONCLUSIONS: Prediction of future CAV development is greatly improved by incorporation of computationally extracted histologic features. These results suggest morphologic details contained within regularly obtained biopsy tissue have the potential to enhance precision and personalization of treatment plans for post-heart transplant patients.

Supplemental Digital Content is available in the text., Background: Late gadolinium enhancement (LGE) cardiovascular magnetic resonance (CMR) imaging is the gold standard for noninvasive myocardial tissue characterization but requires intravenous contrast agent administration. It is highly desired to develop a contrast agent–free technology to replace LGE for faster and cheaper CMR scans. Methods: A CMR virtual native enhancement (VNE) imaging technology was developed using artificial intelligence. The deep learning model for generating VNE uses multiple streams of convolutional neural networks to exploit and enhance the existing signals in native T1 maps (pixel-wise maps of tissue T1 relaxation times) and cine imaging of cardiac structure and function, presenting them as LGE-equivalent images. The VNE generator was trained using generative adversarial networks. This technology was first developed on CMR datasets from the multicenter Hypertrophic Cardiomyopathy Registry, using hypertrophic cardiomyopathy as an exemplar. The datasets were randomized into 2 independent groups for deep learning training and testing. The test data of VNE and LGE were scored and contoured by experienced human operators to assess image quality, visuospatial agreement, and myocardial lesion burden quantification. Image quality was compared using a nonparametric Wilcoxon test. Intra- and interobserver agreement was analyzed using intraclass correlation coefficients (ICC). Lesion quantification by VNE and LGE were compared using linear regression and ICC. Results: A total of 1348 hypertrophic cardiomyopathy patients provided 4093 triplets of matched T1 maps, cines, and LGE datasets. After randomization and data quality control, 2695 datasets were used for VNE method development and 345 were used for independent testing. VNE had significantly better image quality than LGE, as assessed by 4 operators (n=345 datasets; P

Rationale: The renin-angiotensin system is a complex regulatory network that maintains normal physiological functions. The role of the renin-angiotensin system in sepsis-induced myocardial dysfunction (SIMD) is poorly defined. AGT (Angiotensinogen) is the unique precursor of the renin-angiotensin system and gives rise to all angiotensin peptides. The effects and mechanisms of AGT in the development of SIMD have not been defined. Objective: To determine a role of AGT in SIMD and investigate the underlying mechanisms. Methods and Results: Either intraperitoneal injection of lipopolysaccharide or cecal ligation and puncture significantly enhanced AGT abundances in liver, heart, and plasma. Deficiency of hepatocyte-derived AGT, rather than cardiomyocyte-derived AGT, alleviated septic cardiac dysfunction in mice and prolonged survival time. Further investigations revealed that the effects of hepatocyte-derived AGT on SIMD were partially associated with augmented Ang II (angiotensin II) production in circulation. In addition, hepatocyte-derived AGT was internalized by LRP1 (LDL [low-density lipoprotein] receptor-related protein 1) in cardiac fibroblasts and subsequently activated NLRP3 (NLR family pyrin domain-containing 3) inflammasome via an Ang II–independent pathway, ultimately promoting SIMD by suppressing SERCA2a (sarco[endo]plasmic reticulum Ca[2+]-ATPase 2a) abundances in cardiomyocytes. Conclusions: Hepatocyte-derived AGT promoted SIMD via both Ang II–dependent and Ang II–independent pathways. We identified a liver-heart axis by which AGT regulated development of SIMD. Our study may provide a potential novel therapeutic target for SIMD.

Supplemental Digital Content is available in the text., Background: Although the 99th percentile is the recommended diagnostic threshold for myocardial infarction, some guidelines also advocate the use of higher troponin thresholds to rule in myocardial infarction at presentation. It is unclear whether the magnitude or change in troponin concentration can differentiate causes of myocardial injury and infarction in practice. Methods: In a secondary analysis of a multicenter randomized controlled trial, we identified 46 092 consecutive patients presenting with suspected acute coronary syndrome without ST-segment–elevation myocardial infarction. High-sensitivity cardiac troponin I concentrations at presentation and on serial testing were compared between patients with myocardial injury and infarction. The positive predictive value and specificity were determined at the sex-specific 99th percentile upper reference limit and rule-in thresholds of 64 ng/L and 5-fold of the upper reference limit for a diagnosis of type 1 myocardial infarction. Results: Troponin was above the 99th percentile in 8188 patients (18%). The diagnosis was type 1 or type 2 myocardial infarction in 50% and 14% and acute or chronic myocardial injury in 20% and 16%, respectively. Troponin concentrations were similar at presentation in type 1 (median [25th–75th percentile] 91 [30–493] ng/L) and type 2 (50 [22–147] ng/L) myocardial infarction and in acute (50 [26–134] ng/L) and chronic (51 [31–130] ng/L) myocardial injury. The 99th percentile and rule-in thresholds of 64 ng/L and 5-fold upper reference limit gave a positive predictive value of 57% (95% CI, 56%–58%), 59% (58%–61%), and 62% (60%–64%) and a specificity of 96% (96%–96%), 96% (96%–96%), and 98% (97%–98%), respectively. The absolute, relative, and rate of change in troponin concentration were highest in patients with type 1 myocardial infarction (P

PURPOSE To evaluate any significant differences in myocardial strain between hypertrophic obstructive cardiomyopathy (HOCM) and nonobstructive ones (HNCM), as assessed by cardiac magnetic resonance feature tracking (CMR-FT). MATERIALS AND METHODS A total of 17 patients (mean age: 54±14 y) with echocardiographic diagnosis of HOCM (left ventricular outflow tract obstruction peak gradient ≥30 mm Hg), 19 patients (mean age: 49±16 y) with HNCM (peak gradient

Rationale: Tissue inflammation and subsequent fibrosis contribute to ventricle remodelling after ischemic injury and have emerged as viable therapeutic targets. Comparatively, little is understood about the dynamics of inflammation and fibrosis in nonischemic heart failure, which is challenging to interrogate longitudinally. Objective: To investigate the interplay between ventricle loading conditions, tissue inflammation, and progressive fibrosis using noninvasive multimodality molecular imaging to characterize these processes in pressure overload heart failure. Methods and Results: We evaluated cardiac inflammation using positron emission tomography radiotracer 68 Ga-pentixafor, which binds to chemokine receptor CXCR4 (CXC-motif receptor 4). Over the first 7 days after transverse aortic constriction, CXCR4 imaging identified diffuse elevated myocardial inflammation throughout the left ventricle (+34%, P P =0.003). The persistent imaging signal correlated to increased tissue fibrosis on histology. Molecular imaging at 1 week after surgery correlated independently with the change in ventricle geometry over the subsequent 3 weeks (CXCR4, r partial =0.670, P =0.024; T1, r partial =0.689, P =0.019). Alleviation of ventricle pressure by mechanical unloading restored not only cardiac function and geometry but also attenuated global inflammation and normalized T1 relaxation time. This finding demonstrates the capacity to monitor therapeutic intervention by serial molecular imaging. Conclusions: Inflammation and fibrosis are implicated in the early response to pressure overload and may be sensitively monitored by multimodality imaging. Such multimodality molecular imaging approaches may guide novel treatment strategies in nonischemic heart failure.

Cardiac magnetic resonance imaging (MRI) is widely applied for the noninvasive assessment of cardiac structure and function, and for tissue characterization. For more than 2 decades, 1.5 T has been considered the field strength of choice for cardiac MRI. Although the number of 3-T systems significantly increased in the past 10 years and numerous new developments were made, challenges seem to remain that hamper a widespread clinical use of 3-T MR systems for cardiac applications. As the number of clinical cardiac applications is increasing, with each having their own benefits at both field strengths, no "holy grail" field strength exists for cardiac MRI that one should ideally use. This review describes the physical differences between 1.5 and 3 T, as well as the effect of these differences on major (routine) cardiac MRI applications, including functional imaging, edema imaging, late gadolinium enhancement, first-pass stress perfusion, myocardial mapping, and phase contrast flow imaging. For each application, the advantages and limitations at both 1.5 and 3 T are discussed. Solutions and alternatives are provided to overcome potential limitations. Finally, we briefly elaborate on the potential use of alternative field strengths (ie, below 1.5 T and above 3 T) for cardiac MRI and conclude with field strength recommendations for the future of cardiac MRI.

Left ventricular hypertrophy (LVH) makes the heart vulnerable to ischemia/reperfusion (IR) injury. Angiotensin (Ang) (1-7) is recognized as a cardioprotective peptide. We investigated the effect of polyphenol resveratrol on myocardial IR injury after hypertrophy and examined cardiac content of Ang (1-7) and transcription of its receptor (MasR). Rats were divided into sham-operated, LVH, IR, LVH + IR, and resveratrol + LVH + IR groups. Myocardial hypertrophy and IR models were created by abdominal aortic banding and left coronary artery occlusion, respectively. To evaluate the electrocardiogram parameters and incidence of arrhythmias, electrocardiogram was recorded by subcutaneous leads (lead II). Blood pressure was measured through the left carotid artery. Infarct size was determined by the triphenyl tetrazolium chloride staining. The Ang (1-7) level was evaluated by immunohistochemistry. The Mas receptor mRNA level was assessed by the real-time real time reverse transcription polymerase chain reaction technique. QT-interval duration, infarct size, and incidence of ischemia-induced arrhythmia were significantly higher in the LVH + IR group. However, in the resveratrol-treated group, these parameters were decreased significantly. The cardiac level of Ang (1-7) was decreased in untreated hypertrophied hearts (LVH and LVH + IR groups). Pretreatment with resveratrol normalized the cardiac level of Ang (1-7). The mRNA level of Mas receptor was increased in all of hypertrophied hearts in the presence or absence of resveratrol. Resveratrol can decrease IR injury in rats with LVH. The anti-ischemic effect of resveratrol may be related to the enhancement of Ang (1-7)/MasR axis.

Rationale: While respiratory failure is a frequent and clinically significant outcome of coronavirus disease 2019 (COVID-19), cardiac complications are a common feature in hospitalized COVID-19 patients and are associated with worse patient outcomes. The cause of cardiac injury in COVID-19 patients is not yet known. Case reports of COVID-19 autopsy heart samples have demonstrated abnormal inflammatory infiltration of macrophages in heart tissues. Objective: Generate an immunocardiac coculture platform to model macrophage-mediated hyperinflammation in COVID-19 hearts and screen for drugs that can block the macrophage-mediated inflammation. Methods and Results: We systematically compared autopsy samples from non–COVID-19 donors and COVID-19 patients using RNA sequencing and immunohistochemistry. We observed strikingly increased expression levels of CCL2 (C-C motif chemokine ligand 2) and macrophage infiltration in heart tissues of COVID-19 patients. We generated an immunocardiac coculture platform containing human pluripotent stem cell–derived cardiomyocytes and macrophages. We found that macrophages induce increased reactive oxygen species and apoptosis in cardiomyocytes by secreting IL (interleukin)-6 and TNF-α (tumor necrosis factor alpha) after Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) exposure. Using this immunocardiac coculture platform, we performed a high content screen and identified ranolazine and tofacitinib as compounds that protect cardiomyocytes from macrophage-induced cardiotoxicity. Conclusions: We established an immuno-host coculture system to study macrophage-induced host cell damage following SARS-CoV-2 infection and identified Food and Drug Administration–approved drug candidates that alleviate the macrophage-mediated hyperinflammation and cellular injury.

Cardiac wall stress induces local and systemic inflammatory responses that are increasingly recognized as key modulators of extracellular matrix remodeling. Hyaluronic acid interacts with immune cells and mesenchymal cells thereby modulating profibrotic signals. Here we tested the hypothesis that 4-methylumbelliferone (4-MU), an inhibitor of hyaluronic acid synthesis, would attenuate inflammation and extracellular matrix remodeling of pressure-overloaded myocardium in C57BL/6J male mice fed with 4-MU and subjected to TAC (transverse aortic constriction) surgery. Flow cytometry of immune cells showed TAC-induced leukocytosis due to an increase of neutrophils and monocytes. 4-MU strongly attenuated both circulating and cardiac leukocyte numbers 3 days after TAC. In the hearts, 4-MU reduced the number of CCR2 − resident macrophages. At later time points, 4-MU also prevented the infiltration of heart tissue by bone marrow-derived circulating monocytes leading to reduced cardiac macrophage counts even 7 weeks after TAC. The long-term attenuation of macrophage-driven inflammation was associated with less myocardial fibrosis in 4-MU-treated compared with untreated mice. Unexpectedly, 4-MU also reduced the development of left ventricular hypertrophy and increased cardiac output after TAC without affecting blood pressure. The data demonstrate that 4-MU reduces both resident and invading cardiac macrophages and may be a promising agent to alleviate pressure-overload induced myocardial damage.

PURPOSE Physiological myocardial accumulation of FDG impairs the diagnosis of inflammatory/infectious or tumoral myocardial detection by FDG PET/CT. We prospectively evaluated the addition, 3 hours before imaging, of an intravenous 100-mL lipid emulsion infusion (Intralipid) to a high-fat, low-carbohydrate diet (HFLCD) for at least 2 meals followed by a fast of at least 6 to 12 hours in patients referred for the diagnosis of myocardial inflammation, endocarditis, cardiac or paracardiac masses, intracardiac device, or prosthetic valve infections. METHODS Data of 58 patients consecutively included (28 Intralipid patients, 30 controls with HFLCD alone) were compared. FDG uptake in normal myocardium was scored from 0 (complete myocardial suppression) to 3 (high diffuse uptake). Myocardial maximal, peak, and mean SUV and the rate of interpretable images according to the clinical indication were measured. RESULTS Compared with controls, Intralipid infusion significantly improved the rate of score 0 (89% vs 63%, P = 0.021), of interpretable images according to the clinical indication (100% vs 72%, P = 0.0047) and decreased all myocardial SUV values (eg, SUVmax median, 1.9 [interquartile range, 1.7-2.5] vs 3.1 [interquartile range, 2.3-4.1]; P < 0.001). CONCLUSIONS A lipid emulsion infusion in addition to HFLCD better suppresses cardiac glucose metabolism than HFLCD alone.

Background Myocardial iron deficiency (MID) in heart failure (HF) remains largely unexplored. We aim to establish defining criterion for MID, evaluate its pathophysiological role, and evaluate the applicability of monitoring it non‐invasively in human explanted hearts. Methods and Results Biventricular tissue iron levels were measured in both failing (n=138) and non‐failing control (NFC, n=46) explanted human hearts. Clinical phenotyping was complemented with comprehensive assessment of myocardial remodeling and mitochondrial functional profiles, including metabolic and oxidative stress. Myocardial iron status was further investigated by cardiac magnetic resonance imaging. Myocardial iron content in the left ventricle was lower in HF versus NFC (121.4 [88.1–150.3] versus 137.4 [109.2–165.9] μg/g dry weight), which was absent in the right ventricle. With a priori cutoff of 86.1 μg/g d.w. in left ventricle, we identified 23% of HF patients with MID (HF‐MID) associated with higher NYHA class and worsened left ventricle function. Respiratory chain and Krebs cycle enzymatic activities were suppressed and strongly correlated with depleted iron stores in HF‐MID hearts. Defenses against oxidative stress were severely impaired in association with worsened adverse remodeling in iron‐deficient hearts. Mechanistically, iron uptake pathways were impeded in HF‐MID including decreased translocation to the sarcolemma, while transmembrane fraction of ferroportin positively correlated with MID. Cardiac magnetic resonance with T2* effectively captured myocardial iron levels in failing hearts. Conclusions MID is highly prevalent in advanced human HF and exacerbates pathological remodeling in HF driven primarily by dysfunctional mitochondria and increased oxidative stress in the left ventricle. Cardiac magnetic resonance demonstrates clinical potential to non‐invasively monitor MID.

Cardiac injury remains a major cause of morbidity and mortality worldwide. Despite significant advances, a full understanding of why the heart fails to fully recover function after acute injury, and why progressive heart failure frequently ensues, remains elusive. No therapeutics, short of heart transplantation, have emerged to reliably halt or reverse the inexorable progression of heart failure in the majority of patients once it has become clinically evident. To date, most pharmacological interventions have focused on modifying hemodynamics (reducing afterload, controlling blood pressure and blood volume) or on modifying cardiac myocyte function. However, important contributions of the immune system to normal cardiac function and the response to injury have recently emerged as exciting areas of investigation. Therapeutic interventions aimed at harnessing the power of immune cells hold promise for new treatment avenues for cardiac disease. Here, we review the immune response to heart injury, its contribution to cardiac fibrosis, and the potential of immune modifying therapies to affect cardiac repair.

Rationale: Cardiomyopathy is characterized by the deposition of extracellular matrix by activated resident cardiac fibroblasts called myofibroblasts. There are currently no therapeutic approaches to blunt the development of pathological fibrosis and ventricle chamber stiffening that ultimately leads to heart failure. Objective: We undertook a high-throughput screen to identify small molecule inhibitors of myofibroblast activation that might limit the progression of heart failure. We evaluated the therapeutic efficacy of the polyether ionophore salinomycin in patient-derived cardiac fibroblasts and preclinical mouse models of ischemic and nonischemic heart failure. Methods and Results: Here, we demonstrate that salinomycin displays potent anti-fibrotic activity in cardiac fibroblasts obtained from heart failure patients. In preclinical studies, salinomycin prevents cardiac fibrosis and functional decline in mouse models of ischemic and nonischemic heart disease. Remarkably, interventional treatment with salinomycin attenuates preestablished pathological cardiac remodeling secondary to hypertension and limits scar expansion when administered after a severe myocardial infarction. Mechanistically, salinomycin inhibits cardiac fibroblast activation by preventing p38/MAPK (mitogen activated protein kinase) and Rho signaling. Salinomycin also promotes cardiomyocyte survival and improves coronary vessel density, suggesting that cardioprotection conferred by salinomycin occurs via the integration of multiple mechanisms in multiple relevant cardiac cell types. Conclusions: These data establish salinomycin as an antifibrotic agent that targets multiple cardioprotection pathways, thereby holding promise for the treatment of heart failure patients.

Alterations in cardiac energy metabolism contribute to the severity of heart failure. However, the energy metabolic changes that occur in heart failure are complex and are dependent not only on the severity and type of heart failure present but also on the co-existence of common comorbidities such as obesity and type 2 diabetes. The failing heart faces an energy deficit, primarily because of a decrease in mitochondrial oxidative capacity. This is partly compensated for by an increase in ATP production from glycolysis. The relative contribution of the different fuels for mitochondrial ATP production also changes, including a decrease in glucose and amino acid oxidation, and an increase in ketone oxidation. The oxidation of fatty acids by the heart increases or decreases, depending on the type of heart failure. For instance, in heart failure associated with diabetes and obesity, myocardial fatty acid oxidation increases, while in heart failure associated with hypertension or ischemia, myocardial fatty acid oxidation decreases. Combined, these energy metabolic changes result in the failing heart becoming less efficient (ie, a decrease in cardiac work/O 2 consumed). The alterations in both glycolysis and mitochondrial oxidative metabolism in the failing heart are due to both transcriptional changes in key enzymes involved in these metabolic pathways, as well as alterations in NAD redox state (NAD + and nicotinamide adenine dinucleotide levels) and metabolite signaling that contribute to posttranslational epigenetic changes in the control of expression of genes encoding energy metabolic enzymes. Alterations in the fate of glucose, beyond flux through glycolysis or glucose oxidation, also contribute to the pathology of heart failure. Of importance, pharmacological targeting of the energy metabolic pathways has emerged as a novel therapeutic approach to improving cardiac efficiency, decreasing the energy deficit and improving cardiac function in the failing heart.

The autonomic nervous system controls cardiac performance on a beat-to-beat basis in order to match regional blood flow demand. To that end, there is continuous interaction among central autonomic areas (anterior insula, anterior cingulate cortex, amygdala, hypothalamus, periaqueductal gray matter, parabrachial nucleus, and medulla), preganglionic sympathetic and parasympathetic efferent neurons, and intrinsic cardiac ganglia.1,2 Cardiac sympathetic and parasympathetic outputs have been classically thought to act in a reciprocal antagonistic fashion, whereby sympathetic stimulation increases heart rate (chronotropy), atrioventricular conduction (dromotropy), and myocardial contractility (inotropy), whereas parasympathetic stimulation reduces heart rate and atrioventricular conduction. There is evidence, however, for a complex and redundant organization, as cardiac control is mediated by feedback loops organized at 3 main levels: the intrinsic cardiac nervous system, the intrathoracic extracardiac ganglia, and the central autonomic nervous system. These systems are in constant communication, and at each level, afferent signals provide feedback information to neurons that in turn affect efferent control of the heart.1,3

Rationale: Increased myocardial activity of CaMKII (Ca/calmodulin-dependent kinase II) leads to heart failure and arrhythmias. In Drosophila neurons, interaction of CaMKII with CASK (Ca/CaM-dependent serine protein kinase) has been shown to inhibit CaMKII activity, but the consequences of this regulation for heart failure and ventricular arrhythmias are unknown. Objective: We hypothesize that CASK associates with CaMKII in human and mouse hearts thereby limiting CaMKII activity and that altering CASK expression in mice changes CaMKII activity accordingly, with functional consequences for contractile function and arrhythmias. Methods and Results: Immunoprecipitation revealed that CASK associates with CaMKII in human hearts. CASK expression is unaltered in heart failure but increased in patients with aortic stenosis. In mice, cardiomyocyte-specific knockout of CASK increased CaMKII-autophosphorylation at the stimulatory T287 site, but reduced phosphorylation at the inhibitory T305/306 site. Knockout of CASK mice showed increased CaMKII-dependent sarcoplasmic reticulum Ca leak, reduced sarcoplasmic reticulum Ca content, increased susceptibility to ventricular arrhythmias, greater loss of ejection fraction, and increased mortality after transverse aortic constriction. Intriguingly, stimulation of the cardiac glucagon-like peptide 1 receptor with exenatide increased CASK expression resulting in increased inhibitory CaMKII T305 phosphorylation, reduced CaMKII activity, and reduced sarcoplasmic reticulum Ca leak in wild type but not CASK-KO. Conclusions: CASK associates with CaMKII in the human heart. Knockout of CASK in mice increases CaMKII activity, leading to contractile dysfunction and arrhythmias. Increasing CASK expression reduces CaMKII activity, improves Ca handling and contractile function.

BACKGROUND For more than 20 years, hip fracture 1-year mortality has remained around 20%. An elevation of the postoperative troponin peak within 72 hours (myocardial injury after noncardiac surgery [MINS]) is associated with a greater risk of short-term mortality in the general population. However, there seem to be conflicting results in the specific population who undergo hip fracture surgery, with some studies finding an association between troponin and mortality and some not. The objective of the present study was to investigate the association of MINS and the short- (before 28th day), intermediate- (before 180th day), and long-term (before 365th day) mortality after hip fracture surgery. METHODS We conducted a single-center retrospective cohort of patients undergoing hip fracture surgery from November 2013 to December 2015. MINS was defined as postoperative troponin peak within the 72 hours >5 ng/L. Four MINS subgroups were defined according to the value of troponin peak (ie, ≥5

Background Imbalance of oxidants/antioxidants results in heart failure, contributing to mortality after burn injury. Cardiac mitochondria are a prime source of reactive oxygen species (ROS), and a mitochondrial-specific antioxidant may improve burn-induced cardiomyopathy. We hypothesize that the mitochondrial-specific antioxidant, Triphenylphosphonium chloride (Mito-TEMPO), could protect cardiac function after burn. Study design Male rats had a 60% total body surface area (TBSA) scald burn injury and were treated with/without Mito-TEMPO (7 mg/kg-1, intraperitoneal) and harvested at 24 hours post-burn. Echocardiography (ECHO) was used for measurement of heart function. Masson Trichrome and hematoxylin and eosin (H & E) staining were used for cardiac fibrosis and immune response. Qualitative polymerase chain reaction (qPCR) was used for mitochondrial DNA replication and gene expression. Results Burn-induced cardiac dysfunction, fibrosis, and mitochondrial damage were assessed by measurement of mitochondrial function, DNA replication, and DNA-encoded electron transport chain-related gene expression. Mito-TEMPO partially improved the abnormal parameters. Burn-induced cardiac dysfunction was associated with crosstalk between the NFE2L2-ARE pathway, PDE5A-PKG pathway, PARP1-POLG-mtDNA replication pathway, and mitochondrial SIRT signaling. Conclusions Mito-TEMPO reversed burn-induced cardiac dysfunction by rescuing cardiac mitochondrial dysfunction. Mitochondria-targeted antioxidants may be an effective therapy for burn-induced cardiac dysfunction.

Supplemental Digital Content is available in the text., Background: Knowledge gaps remain in the epidemiology and clinical implications of myocardial injury in coronavirus disease 2019 (COVID-19). We aimed to determine the prevalence and outcomes of myocardial injury in severe COVID-19 compared with acute respiratory distress syndrome (ARDS) unrelated to COVID-19. Methods: We included intubated patients with COVID-19 from 5 hospitals between March 15 and June 11, 2020, with troponin levels assessed. We compared them with patients from a cohort study of myocardial injury in ARDS and performed survival analysis with primary outcome of in-hospital death associated with myocardial injury. In addition, we performed linear regression to identify clinical factors associated with myocardial injury in COVID-19. Results: Of 243 intubated patients with COVID-19, 51% had troponin levels above the upper limit of normal. Chronic kidney disease, lactate, ferritin, and fibrinogen were associated with myocardial injury. Mortality was 22.7% among patients with COVID-19 with troponin under the upper limit of normal and 61.5% for those with troponin levels >10 times the upper limit of normal (P

Introduction A total of 161 million children a year are growth restricted, leading to a 47% increased risk of chronic disease in adulthood. Physical activity (PA) reduces the risk of mortality from chronic disease. The purpose of the present investigation was to determine the effect of a PA intervention (wheel running) on cardiac and skeletal muscle capacities in gestational (GUN) and postnatal (PUN) growth-restricted mice as compared with nonrestricted controls (CON). Methods A low-protein cross-fostering FVB mouse model was used to induce growth restriction during gestation and the first 21 d of postnatal life. Mouse pups were recovered on a healthy diet until mature and provided wheel access for 3 wk. At completion of the PA intervention, mice underwent maximal exercise testing on a treadmill, echocardiography, and skeletal muscle histology. Results After the PA intervention, CON mice had a 45% improvement in maximal exercise capacity (P = 0.0390) because of cardiac and skeletal muscle adaptations, but GUN and PUN mice did not. Alarmingly, PUN female mice exposed to wheels had 11.45% lower left ventricular volume (P = 0.0540) and 18% lower left ventricle area (P = 0.0585), with blood flow velocities indicative of cardiac fibrosis (GUN had elevated isovolumetric contraction time P = 0.0374; GUN females and PUN males had longer isovolumetric relaxation time P = 0.0703). PUN male mice had mixed skeletal muscle responses with an oxidative shift in the diaphragm (P = 0.0162) but a glycolytic shift in the extensor digitorum longus (P = 0.0647). PUN female mice had a glycolytic shift in the soleus after wheel running. Conclusions Unexpectedly, growth-restricted mice were nonresponders to a PA intervention and displayed negative cardiac outcomes.

Myocardial fibrosis (MF) is a pathological process that accelerates cardiac remodeling in myocardial infarction (MI), and miR-29 has become one of the foci of research into MF. As an alkaloid extracted from Herba leonuri, leonurine (LE) has been found to be an effective natural active ingredient for inhibiting fibrosis in many preclinical experiments. However, whether LE protects against MF after MI through modifying miR-29 remains unclear. The present study aimed to investigate the therapeutic effects of LE on MF, and to elucidate the underlying mechanisms involved. A mouse model of MI was established, followed by administration of LE for 4 weeks. We found that LE effectively improved cardiac function, and attenuated fibrosis and cardiac remodeling in mice post-MI. In vitro, LE simultaneously inhibited proliferation and migration of neonatal mouse cardiac fibroblasts (CFs) exposed to angiotensin II (Ang II), and the activation of collagen synthesis and myofibroblast generation was markedly suppressed by LE. Notably, we found that all mature miR-29 family members were downregulated in the myocardial tissues of mice post-MI, whereas LE significantly upregulated miR-29a-3p expression, and such upregulation was also detected in LE-treated CFs under Ang II stimulation. Knockdown of miR-29a-3p by a specific miRNA inhibitor upregulated the protein levels of TGF-β, collagen III, and collagen I in CFs, and completely reversed the antifibrotic effects of LE on CFs. Our study suggests that LE exerts cardioprotective effects against MF, possibly through the upregulation of miR-29a-3p.

Supplemental Digital Content is available in the text., Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and its resultant clinical presentation, coronavirus disease 2019 (COVID-19), is an emergent cause of mortality worldwide. Cardiac complications secondary to this infection are common; however, the underlying mechanisms of such remain unclear. A detailed cardiac evaluation of a series of individuals with COVID-19 undergoing postmortem evaluation is provided, with 4 aims: (1) describe the pathological spectrum of the myocardium; (2) compare with an alternate viral illness; (3) investigate angiotensin-converting enzyme 2 expression; and (4) provide the first description of the cardiac findings in patients with cleared infection. Methods: Study cases were identified from institutional files and included COVID-19 (n=15: 12 active, 3 cleared), influenza A/B (n=6), and nonvirally mediated deaths (n=6). Salient information was abstracted from the medical record. Light microscopic findings were recorded. An angiotensin-converting enzyme 2 immunohistochemical H-score was compared across cases. Viral detection encompassed SARS-CoV-2 immunohistochemistry, ultrastructural examination, and droplet digital polymerase chain reaction. Results: Male sex was more common in the COVID-19 group (P=0.05). Nonocclusive fibrin microthrombi (without ischemic injury) were identified in 16 cases (12 COVID-19, 2 influenza, and 2 controls) and were more common in the active COVID-19 cohort (P=0.006). Four active COVID-19 cases showed focal myocarditis, whereas 1 case of cleared COVID-19 showed extensive disease. Arteriolar angiotensin-converting enzyme 2 endothelial expression was lower in COVID-19 cases than in controls (P=0.004). Angiotensin-converting enzyme 2 myocardial expression did not differ by disease category, sex, age, or number of patient comorbidities (P=0.69, P=1.00, P=0.46, P=0.65, respectively). SARS-CoV-2 immunohistochemistry showed nonspecific staining, whereas ultrastructural examination and droplet digital polymerase chain reaction were negative for viral presence. Four patients (26.7%) with COVID-19 had underlying cardiac amyloidosis. Cases with cleared infection had variable presentations. Conclusions: This detailed histopathologic, immunohistochemical, ultrastructural, and molecular cardiac series showed no definitive evidence of direct myocardial infection. COVID-19 cases frequently have cardiac fibrin microthrombi, without universal acute ischemic injury. Moreover, myocarditis is present in 33.3% of patients with active and cleared COVID-19 but is usually limited in extent. Histological features of resolved infection are variable. Cardiac amyloidosis may be an additional risk factor for severe disease.

Background: Heart failure (HF) with preserved ejection fraction (HFpEF) constitutes half of all HF but lacks effective therapy. Understanding of its myocardial biology remains limited because of a paucity of heart tissue molecular analysis. Methods: We performed RNA sequencing on right ventricular septal endomyocardial biopsies prospectively obtained from patients meeting consensus criteria for HFpEF (n=41) contrasted with right ventricular septal tissue from patients with HF with reduced ejection fraction (HFrEF, n=30) and donor controls (n=24). Principal component analysis and hierarchical clustering tested for transcriptomic distinctiveness between groups, effect of comorbidities, and differential gene expression with pathway enrichment contrasted HF groups and donor controls. Within HFpEF, non–negative matrix factorization and weighted gene coexpression analysis identified molecular subgroups, and the resulting clusters were correlated with hemodynamic and clinical data. Results: Patients with HFpEF were more often women (59%), African American (68%), obese (median body mass index 41), and hypertensive (98%), with clinical HF characterized by 65% New York Heart Association Class III or IV, nearly all on a loop diuretic, and 70% with a HF hospitalization in the previous year. Principal component analysis separated HFpEF from HFrEF and donor controls with minimal overlap, and this persisted after adjusting for primary comorbidities: body mass index, sex, age, diabetes, and renal function. Hierarchical clustering confirmed group separation. Nearly half the significantly altered genes in HFpEF versus donor controls (1882 up, 2593 down) changed in the same direction in HFrEF; however, 5745 genes were uniquely altered between HF groups. Compared with controls, uniquely upregulated genes in HFpEF were enriched in mitochondrial adenosine triphosphate synthesis/electron transport, pathways downregulated in HFrEF. HFpEF-specific downregulated genes engaged endoplasmic reticulum stress, autophagy, and angiogenesis. Body mass index differences largely accounted for HFpEF upregulated genes, whereas neither this nor broader comorbidity adjustment altered pathways enriched in downregulated genes. Non–negative matrix factorization identified 3 HFpEF transcriptomic subgroups with distinctive pathways and clinical correlates, including a group closest to HFrEF with higher mortality, and a mostly female group with smaller hearts and proinflammatory signaling. These groupings remained after sex adjustment. Weighted gene coexpression analysis yielded analogous gene clusters and clinical groupings. Conclusions: HFpEF exhibits distinctive broad transcriptomic signatures and molecular subgroupings with particular clinical features and outcomes. The data reveal new signaling targets to consider for precision therapeutics.

Rationale: Cardiac ECM (extracellular matrix) comprises a dynamic molecular network providing structural support to heart tissue function. Understanding the impact of ECM remodeling on cardiac cells during heart failure (HF) is essential to prevent adverse ventricular remodeling and restore organ functionality in affected patients. Objectives: We aimed to (1) identify consistent modifications to cardiac ECM structure and mechanics that contribute to HF and (2) determine the underlying molecular mechanisms. Methods and Results: We first performed decellularization of human and murine ECM (decellularized ECM) and then analyzed the pathological changes occurring in decellularized ECM during HF by atomic force microscopy, 2-photon microscopy, high-resolution 3-dimensional image analysis, and computational fluid dynamics simulation. We then performed molecular and functional assays in patient-derived cardiac fibroblasts based on YAP (yes-associated protein)-transcriptional enhanced associate domain (TEAD) mechanosensing activity and collagen contraction assays. The analysis of HF decellularized ECM resulting from ischemic or dilated cardiomyopathy, as well as from mouse infarcted tissue, identified a common pattern of modifications in their 3-dimensional topography. As compared with healthy heart, HF ECM exhibited aligned, flat, and compact fiber bundles, with reduced elasticity and organizational complexity. At the molecular level, RNA sequencing of HF cardiac fibroblasts highlighted the overrepresentation of dysregulated genes involved in ECM organization, or being connected to TGFβ1 (transforming growth factor β1), interleukin-1, TNF-α, and BDNF signaling pathways. Functional tests performed on HF cardiac fibroblasts pointed at mechanosensor YAP as a key player in ECM remodeling in the diseased heart via transcriptional activation of focal adhesion assembly. Finally, in vitro experiments clarified pathological cardiac ECM prevents cell homing, thus providing further hints to identify a possible window of action for cell therapy in cardiac diseases. Conclusions: Our multiparametric approach has highlighted repercussions of ECM remodeling on cell homing, cardiac fibroblast activation, and focal adhesion protein expression via hyperactivated YAP signaling during HF.