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Background: Patients with normal resting left ventricular ejection fraction (LVEF) without either coronary artery disease (CAD) or a hypertensive response can paradoxically develop reduced LVEF during exercise stress echocardiography (ESE). The clinical phenotype and outcomes of these patients is unknown. Hypothesis: Patients who paradoxically develop reduced LVEF during exercise may represent a sub-phenotype of heart failure with preserved LVEF (HFpEF). Aims: To describe the baseline characteristics and clinical outcomes of this unique patient population. Methods: Among all ESE performed between January 2003 and December 2022, patients without a hypertensive response to exercise and without CAD by angiogram within 90 days of ESE, who had a resting LVEF ≥50% with a ≥5% LVEF decrease during ESE were identified. All-cause mortality, HF hospitalization, and atrial fibrillation (AF) outcomes were assessed. Kaplan-Meier and Cox regression methods were used to analyze time-to-event outcomes. Results: Among 213,643 stress echocardiograms performed, 134 patients met eligibility criteria (Table 1). The mean age of the population was 66±10 years, 76% were women, and 16% had AF at baseline. Mean LVEF was 58±4% at rest and 43±4% at peak stress. Stress electrocardiogram met criteria for ischemia in 14%. The 10-year all-cause mortality risk was 12.9% (95% CI 5.5-20.3) with 10 (37%) of 27 deaths due to cancer (Figure 1, Panel A). The 10-year estimated risk of HF hospitalization was 17.6% (95% CI 9.0-26.2) (Figure 1, Panel B). Among 112 patients without AF at baseline, the 10-year risk of developing AF was 23.4% (95% CI 13.4-33.4). Conclusions: Patients with exercise-induced reduced LVEF in the absence of obstructive CAD have a high incidence of HF hospitalizations and AF. Given the preponderance of women, risk for AF, HF hospitalizations, and cancer-related deaths, the possibility that this condition is an early sub-phenotype of HFpEF should be investigated.

Background: CDCP1 has been associated with reverse remodeling in human dilated cardiomyopathy (DCM) mediating its effect by reducing cardiac fibrosis which has been demonstrated in-vitro using human cardiac fibroblasts (CF) and in-vivo histologically in mice. However, the role of and the molecular mechanisms by which CDCP1 attenuates cardiac fibrosis in-vivo is unknown. Methods: To characterize the transcriptomic profiles of CDCP1 in cardiac fibrosis, Cdcp1 KO FVB/NJ mice were generated, and implanted with osmotic minipumps containing angiotensin II and phenylephrine (Ang II/PE) or saline at age of 10 weeks. There were 4 experimental groups (6 mice each), Saline_WT, Saline_KO, AngII/PE_WT, and AngII/PE_KO. After 4 weeks of AngII/PE induction, mice were euthanized, RNA was extracted from their heart tissue followed by RNA-seq to explore transcriptomic profiles. Fibrosis was histologically determined using picosirius (PSR) staining and was quantified by percentage of fibrosis area. Results: Histological analysis demonstrated that Cdcp1 KO attenuated severe cardiac fibrosis by 32.7% determined by quantification of percentage of fibrosis area. When comparing the transcriptome-wide gene expression in WT mice hearts from Saline to AngII/PE induction, a total of 316 differentially expressed genes (DEGs) were identified ( Fig. 1A ). Expression of Nppb (encodes ProBNP), a marker for heart failure, was significantly upregulated. The most significantly upregulated DEG after AngII/PE induction was Crlf1 ( Fig. 1A ), a gene predominantly expressed in CF, consistent with previous findings. We next compared transcriptomic profiles of AngII/PE induction WT and Cdcp1 KO mice hearts, to explore the role of CDCP1 in cardiac fibrosis. A total of 163 DEGs were identified ( Fig. 1B ). Notably, Cdcp1 -mediated DEGs enriched GO Pathways associated with extracellular matrix organization (Biological Process) and collagen-containing extracellular matrix (Cellular Component) ( Figs. 1C, 1D ), pivotal processes in cardiac fibrosis. In addition, Cdcp1 KO resulted in several “top” DEGs (including Rnase1, Ccl7, Ccl12 Il21r , and Il6 ) which have known function in inflammation, suggesting that CDCP1 might attenuate cardiac fibrosis through immune regulation . Conclusion: Our findings underscore the pivotal role of CDCP1 in modulating cardiac fibrosis in-vivo, potentially through immune regulation. Targeting CDCP1 may offer promising therapeutic avenues for mitigating myocardial fibrosis.

Background: Electrocardiography-based artificial intelligence (AI-ECG) validated models that detect cardiac disease are increasingly being applied in clinical practice. The utility of such tools to detect insidious cardiac disease in patients with normal baseline left ventricular ejection fraction (LVEF) who paradoxically develop reduced LVEF during exercise stress echocardiography (ESE), and do not have coronary artery disease (CAD) or hypertension, is unknown. Hypothesis: AI-ECG is useful to diagnose insidious cardiac disease and predict clinical outcomes in patients with exercise-induced cardiomyopathy. Aims: To assess the utility of AI ECG in patients with exercise-induced cardiomyopathy. Methods: Among all ESE performed between January 2003 and December 2022, patients without a hypertensive response to exercise and without CAD (confirmed by coronary angiography within 90 days after ESE), with resting LVEF ≥50% and a paradoxical ≥5% LVEF decrease during ESE were identified. A previously validated AI-ECG algorithm that predicts atrial fibrillation (AF), reduced LVEF, and cardiac amyloidosis (CA) was applied to the baseline ECG closest to the time of ESE. The predicted probability of AF, reduced LVEF, and CA if above the published thresholds, was determined. Results: There were 134 patients with exercise-induced cardiomyopathy who were identified. The mean age of this cohort was 66±10 years, 76% were women and 16% had AF at baseline. Mean LVEF was 58±4% at rest and 43±4% at peak stress. The median follow-up period was 6.8 years (IQR 3.0-12.2). Among patients without a baseline history of AF (n=112), AI-ECG identified 29% with a significant probability of AF, which was associated with a subsequent AF diagnosis at univariable analysis (HR 2.505, 95%CI 1.016-6.177, p=0.046). There were 10 patients with an AI-ECG prediction of reduced LVEF among whom 3 were subsequently hospitalized with HF. AI-ECG was positive for CA in 8 and 3 amongst these had subsequent HF hospitalizations (Table). Conclusions: Baseline AI-ECG may help predict subsequent AF and diagnose preclinical amyloid cardiomyopathy in patients who by resting echocardiography do not seem to have cardiac disease but with exercise develop reduced LVEF.

Background: We have previously demonstrated by performing a genome-wide association study that a genetic locus resulting in ↓CDCP1 expression was associated with myocardial recovery in patients with dilated cardiomyopathy (DCM). We have subsequently shown that ↓CDCP1 decreases human cardiac fibroblast proliferation in vitro , however, its potential role in modulating cardiac fibrosis and function in vivo is unknown. Methods: A Cdcp1 knock-out (KO) mouse was generated on FVB/NJ background. Angiotensin II/Phenylephrine (AngII/PE) or saline was infused by an osmotic pump into mice ( Cdcp1 KO n=20; wild type/wt n=18) for 4 weeks. Echocardiography was performed at 0 and 4 weeks. Picrosirius red (PSR) staining was performed on cross-sectional heart tissue to identify cardiac fibrosis, which was quantified, using ImageJ software, as a percentage of left ventricular (LV) area stained by PSR. Results: LV mass index (LVMI) significantly increased in AngII/PE wt mice as compared to saline wt (figure a. 3.65±0.15 mg/g vs 3.05±0.17mg/g, p=0.01), however, AngII/PE Cdcp1 KO mice had significantly decreased LVMI as compared to AngII/PE wt mice (figure a. 3.17±0.09 mg/g vs 3.65±0.15 mg/g, p=0.01). In addition, fractional shortening trended higher in AngII/PE Cdcp1 KO mice as compared to AngII/PE wt mice (figure b. 50.36±2.06% vs 45.48±1.43%, p=0.07). Extent of cardiac fibrosis was significantly higher in AngII/PE wt mice as compared to saline wt (figure c. 15.79±0.49% vs 7.93±0.39%, p<0.0001), however AngII/PE Cdcp1 KO mice had significantly reduced cardiac fibrosis as compared to AngII/PE wt mice (figure c. 9.41±0.43%, p<0.0001). Conclusions: CDCP1 KO significantly reduces pressure over-load induced LV hypertrophy and cardiac fibrosis. Its role as a novel therapeutic target in attenuating fibrosis and improving cardiac function in DCM needs to be further explored.

BACKGROUND: Dilated cardiomyopathy (DCM) is a major cause of heart failure and carries a high mortality rate. Myocardial recovery in DCM-related heart failure patients is highly variable, with some patients having little or no response to standard drug therapy. A genome-wide association study may agnostically identify biomarkers and provide novel insight into the biology of myocardial recovery in DCM. METHODS: A genome-wide association study for change in left ventricular ejection fraction was performed in 686 White subjects with recent-onset DCM who received standard pharmacotherapy. Genome-wide association study signals were subsequently functionally validated and studied in relevant cellular models to understand molecular mechanisms that may have contributed to the change in left ventricular ejection fraction. RESULTS: The genome-wide association study identified a highly suggestive locus that mapped to the 5′-flanking region of the CDCP1 (CUB [complement C1r/C1s, Uegf, and Bmp1] domain containing protein 1) gene (rs6773435; P =7.12×10 −7 ). The variant allele was associated with improved cardiac function and decreased CDCP1 transcription. CDCP1 expression was significantly upregulated in human cardiac fibroblasts (HCFs) in response to the PDGF (platelet-derived growth factor) signaling, and knockdown of CDCP1 significantly repressed HCF proliferation and decreased AKT (protein kinase B) phosphorylation. Transcriptomic profiling after CDCP1 knockdown in HCFs supported the conclusion that CDCP1 regulates HCF proliferation and mitosis. In addition, CDCP1 knockdown in HCFs resulted in significantly decreased expression of soluble ST2 (suppression of tumorigenicity-2), a prognostic biomarker for heart failure and inductor of cardiac fibrosis. CONCLUSIONS: CDCP1 may play an important role in myocardial recovery in recent-onset DCM and mediates its effect primarily by attenuating cardiac fibrosis.

BACKGROUND: Common genetic variants are associated with risk for hypertrophic cardiomyopathy and dilated cardiomyopathy and with left ventricular (LV) traits. Whether these variants are associated with myocardial fibrosis, an important pathophysiological mediator of cardiomyopathy, is unknown. METHODS: Multi-Ethnic Study of Atherosclerosis participants with T1-mapping cardiac magnetic resonance imaging in-whom extracellular volume was assessed, and genotyping information was available were included (N=1255). Log extracellular volume (%) was regressed on 50 candidate single nucleotide polymorphisms (previously identified to be associated with hypertrophic cardiomyopathy, dilated cardiomyopathy, and LV traits) adjusting for age, sex, diabetes, blood pressure, and principal components of ancestry. Ancestry-specific results were pooled by fixed-effect meta-analyses. Gene knockdown experiments were performed in human cardiac fibroblasts. RESULTS: The SMARCB1 rs2186370 intronic variant (minor allele frequency: 0.18 in White and 0.50 in Black participants), previously identified as a risk variant for dilated cardiomyopathy and hypertrophic cardiomyopathy, was significantly associated with increased extracellular volume ( P= 0.0002) after adjusting for confounding clinical variables. The SMARCB1 rs2070458 locus previously associated with increased LV wall thickness and mass was similarly significantly associated with increased extracellular volume ( P= 0.0002). The direction of effect was similar in all 4 ancestry groups, but the effect was strongest in Black participants. The variants are strong expression quantitative loci in human LV tissue and associated with genotype-dependent decreased expression of SMARCB1 ( P= 7.3×10 -22 ). SMARCB1 knockdown in human cardiac fibroblasts resulted in increased TGF (transforming growth factor)-β1–mediated α-smooth muscle actin and collagen expression. CONCLUSIONS: Common genetic variation in SMARCB1 previously associated with risk for cardiomyopathies and increased LV wall thickness is associated with increased cardiac magnetic resonance imaging–based myocardial fibrosis and increased TGF-β1 mediated myocardial fibrosis in vitro. Whether these findings suggest a pathophysiologic link between myocardial fibrosis and cardiomyopathy risk remains to be proven.

Introduction: Genome-wide association studies have identified common genetic variants associated with hypertrophic (HCM) and dilated cardiomyopathy (DCM) and left ventricular (LV) characteristics. However, the association of these variants with myocardial fibrosis (MF), an important pathophysiological mediator of cardiomyopathy, is unknown. Hypothesis: We used the Multi-Ethnic Study of Atherosclerosis (MESA), to evaluate the association of these loci with interstitial MF measured by cardiac MRI (CMR). Methods: Unrelated MESA participants with T1-mapping CMR and no history of MI or heart failure were included (n=1,235). We used the extracellular volume (ECV) fraction as a well-established surrogate of interstitial MF. Genotyping was performed by Affymetrix Human SNP array 6.0, and imputation was performed using the TOPMED reference panel. Log ECV(%) was regressed on 50 candidate SNPs, in each ethnicity/race group, adjusting for age, sex, and population stratification principal component. The race-specific results were pooled by fixed-effect meta-analyses using METASOFT. Results: The SMARCB1 rs2186370 intronic variant, previously identified as a risk variant for DCM and HCM, was associated with ECV (p=0.0004). The rs2186370 A allele (frequency: 0.18 in Whites, and 0.50 in African Americans) was associated with a 1.6% increase in ECV. The rs2070458 A allele (another SMARCB1 intronic variant), in complete linkage disequilibrium with rs2186370, was known previously to be associated with increased LV wall thickness, mass, and concentricity. The direction of effect was similar in all four ancestry groups, but the effect was strongest in African Americans. These variants are strong expression quantitative loci (eQTLs) in human LV tissue and are associated with genotype-dependent expression of SMARCB1 ( p =7.3х10 -22 ) and MMP11 ( p =2.5х10 -24 ). Conclusions: In conclusion, variants in two linked SMARCB1 loci previously associated with HCM, DCM and LV traits, are associated with CMR-based interstitial MF. These loci are eQTL not only for SMARCB1 but also for MMP11 an important mediator of MF . These findings underscore the important link between MF and CM, and potentially provide novel mechanistic targets in understanding the development of CM.

Introduction: It has been previously demonstrated that cardiomyopathy predisposing common genetic variation in SMARCB1 is associated with interstitial myocardial fibrosis (MF) as determined by cardiac MRI (CMR) linking the development of cardiomyopathy with MF. SMARCB1 is known to be a tumor suppressor, but it’s role in the pathophysiology of MF and fibroblast physiology has not been functionally validated. Hypothesis: SMARCB1 plays an important role in regulating human cardiac fibroblast (HCF) differentiation/activation and collagen deposition, which are the critical steps in the development of MF. Methods: Cultured HCFs were treated with TGF-β1 (10ng/ml) for 48hrs to transdifferentiate into myofibroblasts, which are characterized by increased expression of α-smooth muscle actin (α-SMA, ACTA2) and collagen I (COL1A1). HCFs were transfected by siRNA using Lipofectamine™ RNAiMAX Transfection Reagent to knock-down (KD) the expression of SMARCB1 . Total RNA and protein were extracted from cell lysate followed by qPCR and Western blot (WB) to quantify the expression level of SMARCB1, ACTA2 and COL1A1. Triplicate experiments were performed using biologically independent samples. For statistical analysis, a paired two-tail t-test was used. Results: HCFs treatment with TGF-β1, resulted in a significant decrease in expression of SMARCB1 (p=0.031) with accompanying significant increase in expression of ACTA2 (p=0.025) and COL1A1 (p=0.0015) as compared to control by qPCR and WB. SMARCB1 KD resulted in a further significant increase in expression of ACTA2 (p=0.018) and COL1A1 (p=0.028) as compared to non-target siRNA control group at both the transcript and protein level. Conclusion: We demonstrate for the first time that a gene associated with the development of cardiomyopathy SMARCB1 mediates TGF-β1 induced cardiac fibrosis. These findings suggest SMARCB1 as a potential therapeutic target to attenuate MF in cardiomyopathy.

AbstractObjectiveUse of tacrolimus in mild to moderate myasthenia gravis (MG) is generally limited to glucocorticoid‐refractory cases; the advantage of mono‐tacrolimus over mono‐glucocorticoids is unknown.MethodsWe included mild to moderate MG patients treated with mono‐tacrolimus (mono‐TAC) or mono‐glucocorticoids (mono‐GC). The correlation between the immunotherapy options and the treatment efficacy and side effects were examined in 1:1 propensity‐score matching. The main outcome was time to minimal manifestations status or better (MMS or better). Secondary outcomes include time to relapse, the mean changes in Myasthenia Gravis‐specific Activities of Daily Living (MG‐ADL) scores and the rate of adverse events.ResultsBaseline characteristics showed no difference between matched groups (49 matched pairs). There were no differences in median time to MMS or better between the mono‐TAC group and mono‐GC group (5.1 vs. 2.8 months: unadjusted hazard ratio [HR], 0.73; 95% CI, 0.46–1.16; p = 0.180), as well as in median time to relapse (data unavailable for the mono‐TAC group since 44 of 49 [89.8%] participants remained in MMS or better; 39.7 months in mono‐GC group: unadjusted HR, 0.67; 95% CI, 0.23–1.97; p = 0.464). Changes in MG‐ADL scores between the two groups were similar (mean differences, 0.3; 95% CI, −0.4 to 1.0; p = 0.462). The rate of adverse events was lower in the mono‐TAC group compared to the mono‐GC group (24.5% vs. 55.1%, p = 0.002).InterpretationMono‐tacrolimus performs superior tolerability with non‐inferior efficacy compared to mono‐glucocorticoids in mild to moderate myasthenia gravis patients who refuse or have a contraindication to glucocorticoids.

Abstract Fetal-derived tissue-resident macrophages exhibit stem cell-like features of self-renewal in adulthood to maintain macrophage population during homeostasis and/or various insults. However, little is known about the cellular and molecular mechanisms modulating proliferative and inflammatory fate decisions of tissue-resident macrophages in vivo. Here, we show that WNT-β-catenin signaling inhibited lung-resident alveolar macrophage (AM) self-renewal, while simultaneously promoted AM inflammatory activities in vitro and in vivo during influenza virus infection. Mechanistically, WNT engagement facilitated the binding of β-catenin with HIF-1α over its conventional binding partner TCF-4. Such a binding choice led to the elevated macrophage inflammation in a glycolysis-dependent manner, while inhibited AM self-renewal by causing mitochondrial damage and impairing oxidative phosphorylation. Thus, AM self-renewal and inflammatory activity are uncoupled by WNT-β-catenin signaling through HIF-1α-mediated cellular metabolic choice. Importantly, we showed that AM with high HIF-1α activity had limited proliferative capacity and produced inflammatory cytokines, while AM with low HIF-1α activity were highly proliferative and expressed genes associated with tissue repair function in vivo during influenza virus infection. In accordance, we demonstrated that AM proliferation and repopulation were needed for optimal lung repair following the clearance of influenza virus in the respiratory tract. Our results have revealed key mechanisms modulating macrophage fate choice between progeny production versus inflammatory effector activity, and subsequent effects on tissue inflammation and repair.