Circulating Proteome Analysis Identifies Reduced Inflammation After Initiation of Hemodynamic Support with Either Veno-Arterial Extracorporeal Membrane Oxygenation or Impella in Patients with Cardiogenic Shock.

In-hospital mortality associated with cardiogenic shock (CS) remains high despite the use of percutaneous assist devices. We sought to determine whether support with VA-ECMO or Impella in patients with CS alters specific components of the plasma proteome. Plasma samples were collected before device implantation and 72 h after initiation of support in 11 CS patients receiving ECMO or Impella. SOMAscan was used to detect 1305 circulating proteins. Sixty-seven proteins were changed after ECMO (18 upregulated and 49 downregulated, p < 0.05), 38 after Impella (10 upregulated and 28 downregulated, p < 0.05), and only eight proteins were commonly affected. Despite minimal protein overlap, both devices were associated with markers of reduced inflammation and increased apoptosis of inflammatory cells. In summary, ECMO and Impella are associated with reduced expression of inflammatory markers and increased markers of inflammatory cell death. These circulating proteins may serve as novel targets of therapy or biomarkers to tailor AMCS use.

The RNA editor ADAR2 promotes immune cell trafficking by enhancing endothelial responses to interleukin-6 during sterile inflammation.

Immune cell trafficking constitutes a fundamental component of immunological response to tissue injury, but the contribution of intrinsic RNA nucleotide modifications to this response remains elusive. We report that RNA editor ADAR2 exerts a tissue- and stress-specific regulation of endothelial responses to interleukin-6 (IL-6), which tightly controls leukocyte trafficking in IL-6-inflamed and ischemic tissues. Genetic ablation of ADAR2 from vascular endothelial cells diminished myeloid cell rolling and adhesion on vascular walls and reduced immune cell infiltration within ischemic tissues. ADAR2 was required in the endothelium for the expression of the IL-6 receptor subunit, IL-6 signal transducer (IL6ST; gp130), and subsequently, for IL-6 trans-signaling responses. ADAR2-induced adenosine-to-inosine RNA editing suppressed the Drosha-dependent primary microRNA processing, thereby overwriting the default endothelial transcriptional program to safeguard gp130 expression. This work demonstrates a role for ADAR2 epitranscriptional activity as a checkpoint in IL-6 trans-signaling and immune cell trafficking to sites of tissue injury.

Circulating and Myocardial Cytokines Predict Cardiac Structural and Functional Improvement in Patients With Heart Failure Undergoing Mechanical Circulatory Support.

Background Recent prospective multicenter data from patients with advanced heart failure demonstrated that left ventricular assist device (LVAD) support combined with standard heart failure medications, induced significant cardiac structural and functional improvement, leading to high rates of LVAD weaning in selected patients. We investigated whether preintervention myocardial and systemic inflammatory burden could help identify the subset of patients with advanced heart failure prone to LVAD-mediated cardiac improvement to guide patient selection, treatment, and monitoring. Methods and Results Ninety-three patients requiring durable LVAD were prospectively enrolled. Myocardial tissue and blood were acquired during LVAD implantation, for measurement of inflammatory markers. Cardiac structural and functional improvement was prospectively assessed via serial echocardiography. Eleven percent of the patients showed significant reverse remodeling following LVAD support (ie, responders). Circulating tumor necrosis factor alpha, interleukin (IL)-4, IL-5, IL-6, IL-7, IL-13, and interferon gamma were lower in responders, compared with nonresponders (P<0.05, all comparisons). The myocardial tissue signal transducer and activator of transcription-3, an inflammatory response regulator, was less activated in responders (P=0.037). Guided by our tissue studies and a multivariable dichotomous regression analysis, we identified that low levels of circulating interferon gamma (odds ratio [OR], 0.06; 95% CI, 0.01-0.35) and tumor necrosis factor alpha (OR, 0.05; 95% CI, 0.00-0.43), independently predict cardiac improvement, creating a 2-cytokine model effectively predicting responders (area under the curve, 0.903; P<0.0001). Conclusions Baseline myocardial and systemic inflammatory burden inversely correlates with cardiac improvement following LVAD support. A circulating 2-cytokine model predicting significant reverse remodeling was identified, warranting further investigation as a practical preintervention tool in identifying patients prone to LVAD-mediated cardiac improvement and device weaning.

A Rare Case of Disseminated Tuberculosis and Hematological Malignancy in a Heart Transplant Recipient.

A 77-year-old man who underwent a heart transplant 7 years ago presented with multiple bloody bowel movements. Endoscopic and histologic evaluation revealed chronic active ileitis, granulomatous inflammation, multinucleated giant cells, and a rare, equivocal acid-fast bacterium in the terminal ileum. Positive sputum cultures for Mycobacterium tuberculosis and acid-fast bacilli established a diagnosis of intestinal tuberculosis, and RIPE (rifabutin, isoniazid, pyrazinamide, ethambutol) therapy was initiated. Elevated IgG levels on quantitative immunoglobulin testing and a bone marrow biopsy specimen of ≥60% plasma cells confirmed the diagnosis of multiple myeloma that later transformed into its aggressive form, plasma cell leukemia. Induction chemotherapy was initiated; however, the patient experienced retroperitoneal bleeding and pancytopenias, limiting the continuation of chemotherapy, and as a result, the patient was transitioned to palliative care.

State-of-the-art machine learning algorithms for the prediction of outcomes after contemporary heart transplantation: Results from the UNOS database.

PURPOSE: We sought to develop and validate machine learning (ML) models to increase the predictive accuracy of mortality after heart transplantation (HT). METHODS AND RESULTS: We included adult HT recipients from the United Network for Organ Sharing (UNOS) database between 2010 and 2018 using solely pre-transplant variables. The study cohort comprised 18 625 patients (53 ± 13 years, 73% males) and was randomly split into a derivation and a validation cohort with a 3:1 ratio. At 1-year after HT, there were 2334 (12.5%) deaths. Out of a total of 134 pre-transplant variables, 39 were selected as highly predictive of 1-year mortality via feature selection algorithm and were used to train five ML models. AUC for the prediction of 1-year survival was .689, .642, .649, .637, .526 for the Adaboost, Logistic Regression, Decision Tree, Support Vector Machine, and K-nearest neighbor models, respectively, whereas the Index for Mortality Prediction after Cardiac Transplantation (IMPACT) score had an AUC of .569. Local interpretable model-agnostic explanations (LIME) analysis was used in the best performing model to identify the relative impact of key predictors. ML models for 3- and 5-year survival as well as acute rejection were also developed in a secondary analysis and yielded AUCs of .629, .609, and .610 using 27, 31, and 91 selected variables respectively. CONCLUSION: Machine learning models showed good predictive accuracy of outcomes after heart transplantation.

Plasma Proteomic Profiling in Hypertrophic Cardiomyopathy Patients before and after Surgical Myectomy Reveals Post-Procedural Reduction in Systemic Inflammation.

Left Ventricular Outflow Tract (LVOT) obstruction occurs in approximately 70% of Hypertrophic Cardiomyopathy (HCM) patients and currently requires imaging or invasive testing for diagnosis, sometimes in conjunction with provocative physiological or pharmaceutical stimuli. To identify potential biomarkers of LVOT obstruction, we performed proteomics profiling of 1305 plasma proteins in 12 HCM patients with documented LVOT obstruction, referred for surgical myectomy. Plasma was collected at the surgical preoperative visit, approximately one month prior to surgery and then at the post-surgical visit, approximately 3 months later. Proteomic profiles were generated using the aptamer-based SOMAscan assay. Principal Component Analysis using the highest statistically significant proteins separated all preoperative samples from all postoperative samples. Further analysis revealed a set of 25 proteins that distinguished the preoperative and postoperative states with a paired t-test p-value of <0.01. Ingenuity Pathway analysis facilitated the generation of protein interaction networks and the elucidation of key upstream regulators of differentially expressed proteins, such as interferon-γ, TGF-ß1, and TNF. Biological pathways affected by surgery included organ inflammation, migration, and motility of leukocytes, fibrosis, vasculogenesis, angiogenesis, acute coronary events, endothelial proliferation, eicosanoid metabolism, calcium flux, apoptosis, and morphology of the cardiovascular system. Our results indicate that surgical relief of dynamic outflow tract obstruction in HCM patients is associated with unique alterations in plasma proteomic profiles that likely reflect improvement in organ inflammation and physiological function.

The pyruvate-lactate axis modulates cardiac hypertrophy and heart failure.

The metabolic rewiring of cardiomyocytes is a widely accepted hallmark of heart failure (HF). These metabolic changes include a decrease in mitochondrial pyruvate oxidation and an increased export of lactate. We identify the mitochondrial pyruvate carrier (MPC) and the cellular lactate exporter monocarboxylate transporter 4 (MCT4) as pivotal nodes in this metabolic axis. We observed that cardiac assist device-induced myocardial recovery in chronic HF patients was coincident with increased myocardial expression of the MPC. Moreover, the genetic ablation of the MPC in cultured cardiomyocytes and in adult murine hearts was sufficient to induce hypertrophy and HF. Conversely, MPC overexpression attenuated drug-induced hypertrophy in a cell-autonomous manner. We also introduced a novel, highly potent MCT4 inhibitor that mitigated hypertrophy in cultured cardiomyocytes and in mice. Together, we find that alteration of the pyruvate-lactate axis is a fundamental and early feature of cardiac hypertrophy and failure.

Systemic Inflammatory Burden Correlates with Severity and Predicts Outcomes in Patients with Cardiogenic Shock Supported by a Percutaneous Mechanical Assist Device.

In-hospital mortality associated with cardiogenic shock (CS) remains high despite introduction of mechanical circulatory support. In this study, we aimed to investigate whether systemic inflammation is associated with clinical outcomes in CS. We retrospectively analyzed systemic cytokine levels and the neutrophil-to-lymphocyte ratio (NLR), a marker of low-grade inflammation, among 134 patients with CS supported by VA-ECMO or Impella. Sixty-one percent of patients survived CS and either underwent device explantation or were bridged to LVAD or cardiac transplant. IL6 was the predominant circulating cytokine. IL6 levels were reduced after circulatory support in survivors. NLR pre-device implantation was significantly lower in patients with earlier stages of cardiogenic shock. Compared with non-survivors, survivors had a lower pre-device NLR and NLR was independently predictive of survival after adjusting for other covariates. In summary, NLR is a widely available marker of inflammation and correlates with in-hospital mortality among patients with cardiogenic shock requiring percutaneous mechanical circulatory support. Graphical Abstract Survivors present with lower NLR levels prior to percutaneous device implantation. Both survivors and non survivors present with elevated IL6 levels. IL6 levels decrease after percutaneous support (ECMO or Impella) only in survivors and continue to rise in non-survivors.

Insulin receptor substrates differentially exacerbate insulin-mediated left ventricular remodeling.

Pressure overload (PO) cardiac hypertrophy and heart failure are associated with generalized insulin resistance and hyperinsulinemia, which may exacerbate left ventricular (LV) remodeling. While PO activates insulin receptor tyrosine kinase activity that is transduced by insulin receptor substrate 1 (IRS1), the present study tested the hypothesis that IRS1 and IRS2 have divergent effects on PO-induced LV remodeling. We therefore subjected mice with cardiomyocyte-restricted deficiency of IRS1 (CIRS1KO) or IRS2 (CIRS2KO) to PO induced by transverse aortic constriction (TAC). In WT mice, TAC-induced LV hypertrophy was associated with hyperactivation of IRS1 and Akt1, but not IRS2 and Akt2. CIRS1KO hearts were resistant to cardiac hypertrophy and heart failure in concert with attenuated Akt1 activation. In contrast, CIRS2KO hearts following TAC developed more severe LV dysfunction than WT controls, and this was prevented by haploinsufficiency of Akt1. Failing human hearts exhibited isoform-specific IRS1 and Akt1 activation, while IRS2 and Akt2 activation were unchanged. Kinomic profiling identified IRS1 as a potential regulator of cardioprotective protein kinase G-mediated signaling. In addition, gene expression profiling revealed that IRS1 signaling may promote a proinflammatory response following PO. Together, these data identify IRS1 and Akt1 as critical signaling nodes that mediate LV remodeling in both mice and humans.

Effect of Continuous-Flow Left Ventricular Assist Device Support on Coronary Artery Endothelial Function in Ischemic and Nonischemic Cardiomyopathy.

BACKGROUND: The coronary vasculature encounters a reduction in pulsatility after implementing durable continuous-flow left ventricular assist device (CF-LVAD) circulatory support. Evidence exists that appropriate pulsatility is required to maintain endothelial cell homeostasis. We hypothesized that coronary artery endothelial function would be impaired after CF-LVAD intervention. METHODS AND RESULTS: Coronary arteries from patients with end-stage heart failure caused by ischemic cardiomyopathy (ICM; n=16) or non-ICM (n=22) cardiomyopathy were isolated from the left ventricular apical core, which was removed for the CF-LVAD implantation. In 11 of these patients, paired coronary arteries were obtained from an adjacent region of myocardium after the CF-LVAD intervention (n=6 ICM, 5 non-ICM). Vascular function was assessed ex vivo using isometric tension procedures in these patients and in 7 nonfailing donor controls. Maximal endothelium-dependent vasorelaxation to BK (bradykinin; 10-6-10-10 M) was blunted (P<0.05) in arteries from patients with ICM compared with non-ICM and donor controls, whereas responses to sodium nitroprusside (10-4-10-9 M) were similar among the groups. Contrary to our hypothesis, vasorelaxation responses to BK and sodium nitroprusside were similar before and 219±37 days after CF-LVAD support. Of these patients, an exploratory subgroup analysis revealed that BK-induced coronary artery vasorelaxation was greater (P<0.05) after (87±6%) versus before (54±14%) CF-LVAD intervention in ICM patients, whereas sodium nitroprusside-evoked responses were similar. CONCLUSIONS: Coronary artery endothelial function is not impaired by durable CF-LVAD support and in ICM patients appears to be improved. Investigating coronary endothelial function using in vivo approaches in a larger patient population is warranted.

Genome-wide DNA methylation encodes cardiac transcriptional reprogramming in human ischemic heart failure.

Ischemic cardiomyopathy (ICM) is the clinical endpoint of coronary heart disease and a leading cause of heart failure. Despite growing demands to develop personalized approaches to treat ICM, progress is limited by inadequate knowledge of its pathogenesis. Since epigenetics has been implicated in the development of other chronic diseases, the current study was designed to determine whether transcriptional and/or epigenetic changes are sufficient to distinguish ICM from other etiologies of heart failure. Specifically, we hypothesize that genome-wide DNA methylation encodes transcriptional reprogramming in ICM. RNA-sequencing analysis was performed on human ischemic left ventricular tissue obtained from patients with end-stage heart failure, which enriched known targets of the polycomb methyltransferase EZH2 compared to non-ischemic hearts. Combined RNA sequencing and genome-wide DNA methylation analysis revealed a robust gene expression pattern consistent with suppression of oxidative metabolism, induced anaerobic glycolysis, and altered cellular remodeling. Lastly, KLF15 was identified as a putative upstream regulator of metabolic gene expression that was itself regulated by EZH2 in a SET domain-dependent manner. Our observations therefore define a novel role of DNA methylation in the metabolic reprogramming of ICM. Furthermore, we identify EZH2 as an epigenetic regulator of KLF15 along with DNA hypermethylation, and we propose a novel mechanism through which coronary heart disease reprograms the expression of both intermediate enzymes and upstream regulators of cardiac metabolism such as KLF15.

Clinical and histopathological effects of heart failure drug therapy in advanced heart failure patients on chronic mechanical circulatory support.

AIMS: Adjuvant heart failure (HF) drug therapy in patients undergoing chronic mechanical circulatory support (MCS) is often used in conjunction with a continuous-flow left ventricular assist device (LVAD), but its potential impact is not well defined. The objective of the present study was to examine the effects of conventional HF drug therapy on myocardial structure and function, peripheral organ function and the incidence of adverse events in the setting of MCS. METHODS AND RESULTS: Patients with chronic HF requiring LVAD support were prospectively enrolled. Paired myocardial tissue samples were obtained prior to LVAD implantation and at transplantation for histopathology. The Meds group comprised patients treated with neurohormonal blocking therapy (concurrent beta-blocker, angiotensin-converting enzyme inhibitor/angiotensin receptor blocker, and aldosterone antagonist), and the No Meds group comprised patients on none of these. Both the Meds (n = 37) and No Meds (n = 44) groups experienced significant improvements in cardiac structure and function over the 6 months following LVAD implantation. The degree of improvement was greater in the Meds group, including after adjustment for baseline differences. There were no differences between the two groups in arrhythmias, end-organ injury, or neurological events. In patients with high baseline pre-LVAD myocardial fibrosis, treatment with HF drug therapy was associated with a reduction in fibrosis. CONCLUSIONS: Clinical and histopathological evidence showed that adjuvant HF drug therapy was associated with additional favourable effects on the structure and function of the unloaded myocardium that extended beyond the beneficial effects attributed to LVAD-induced unloading alone. Adjuvant HF drug therapy did not influence the incidence of major post-LVAD adverse events during the follow-up period.

Sheet-Like Remodeling of the Transverse Tubular System in Human Heart Failure Impairs Excitation-Contraction Coupling and Functional Recovery by Mechanical Unloading.

BACKGROUND: Cardiac recovery in response to mechanical unloading by left ventricular assist devices (LVADs) has been demonstrated in subgroups of patients with chronic heart failure (HF). Hallmarks of HF are depletion and disorganization of the transverse tubular system (t-system) in cardiomyocytes. Here, we investigated remodeling of the t-system in human end-stage HF and its role in cardiac recovery. METHODS: Left ventricular biopsies were obtained from 5 donors and 26 patients with chronic HF undergoing implantation of LVADs. Three-dimensional confocal microscopy and computational image analysis were applied to assess t-system structure, density, and distance of ryanodine receptor clusters to the sarcolemma, including the t-system. Recovery of cardiac function in response to mechanical unloading was assessed by echocardiography during turndown of the LVAD. RESULTS: The majority of HF myocytes showed remarkable t-system remodeling, particularly sheet-like invaginations of the sarcolemma. Circularity of t-system components was decreased in HF versus controls (0.37±0.01 versus 0.46±0.02; P<0.01), and the volume/length ratio was increased in HF (0.36±0.01 versus 0.25±0.02 µm2; P<0.0001). T-system density was reduced in HF, leading to increased ryanodine receptor-sarcolemma distances (0.96±0.05 versus 0.64±0.1 µm; P<0.01). Low ryanodine receptor-sarcolemma distances at the time of LVAD implantation predicted high post-LVAD left ventricular ejection fractions (P<0.01) and ejection fraction increases during unloading (P<0.01). Ejection fraction in patients with pre-LVAD ryanodine receptor-sarcolemma distances >1 µm did not improve after mechanical unloading. In addition, calcium transients were recorded in field-stimulated isolated human cardiomyocytes and analyzed with respect to local t-system density. Calcium release in HF myocytes was restricted to regions proximal to the sarcolemma. Local calcium upstroke was delayed (23.9±4.9 versus 10.3±1.7 milliseconds; P<0.05) and more asynchronous (18.1±1.5 versus 8.9±2.2 milliseconds; P<0.01) in HF cells with low t-system density versus cells with high t-system density. CONCLUSIONS: The t-system in end-stage human HF presents a characteristic novel phenotype consisting of sheet-like invaginations of the sarcolemma. Our results suggest that the remodeled t-system impairs excitation-contraction coupling and functional recovery during chronic LVAD unloading. An intact t-system at the time of LVAD implantation may constitute a precondition and predictor for functional cardiac recovery after mechanical unloading.

Impact of Ischemic Heart Failure Etiology on Cardiac Recovery During Mechanical Unloading.

BACKGROUND: Small-scale studies focused mainly on nonischemic cardiomyopathy (NICM) have shown that a subset of left ventricular assist device (LVAD) patients can achieve significant improvement of their native heart function, but the impact of ischemic cardiomyopathy (ICM) has not been specifically investigated. Many patients with acute myocardial infarction are discharged from their index hospitalization without heart failure (HF), only to return much later with overt HF syndrome, mainly caused by chronic remodeling of the noninfarcted region of the myocardium. OBJECTIVES: This study sought to prospectively investigate the effect of ICM HF etiology on LVAD-associated improvement of cardiac structure and function using NICM as control. METHODS: Consecutive patients (n = 154) with documented chronic and dilated cardiomyopathy (ICM, n = 61; NICM, n = 93) requiring durable support with continuous-flow LVAD were prospectively evaluated with serial echocardiograms and right heart catheterizations. RESULTS: In patients supported with LVAD for at least 6 months, we found that 5% of subjects with ICM and 21% of subjects with NICM achieved left ventricular ejection fraction ≥40% (p = 0.034). LV end-diastolic and end-systolic volumes and diastolic function were significantly and similarly improved in patients with ICM and NICM. CONCLUSIONS: LVAD-associated unloading for 6 months resulted in a substantial improvement in myocardial structure, and systolic and diastolic function in 1 in 20 ICM and 1 in 5 NICM patients. These specific incidence and timeline findings may provide guidance in clinical practice and research design for sequencing and prioritizing advanced HF and heart transplantation therapeutic options in patients with ICM and NICM.