JACC: Basic to Translational Science

Heart failure with preserved ejection fraction (HFpEF) is a heterogeneous condition with incompletely defined myocardial mechanisms. Here, using a two-hit murine model of cardiometabolic HFpEF induced by high-fat diet and endothelial nitric oxide synthase inhibition, we define a mitochondrial metabolic phenotype characterized by substrate inflexibility, redox stress, and S-nitrosylation remodeling. While global proteomic changes were modest, metabolomic profiling revealed accumulation of tricarboxylic acid cycle intermediates, increased dicarboxylic acids, and altered redox-associated metabolites, consistent with inefficient oxidative metabolism and mitochondrial redox imbalance in this experimental setting. S-nitrosylation proteomics demonstrated a highly organized and bidirectional remodeling pattern affecting proteins involved in fatty acid/lipid metabolism, carbohydrate metabolism, mitochondrial energy metabolism, amino acid and organic acid metabolism, nucleotide/cofactor metabolism, and redox defense. Beta-hydroxybutyrate (BHB), an alternative mitochondrial substrate, improved basal and ATP-linked respiration, reduced selected TCA-cycle intermediates, lowered mitochondrial reactive oxygen species and the NADH/NAD+ ratio, partially restored the GSH/GSSG ratio, and improved diastolic and functional phenotypes without altering preserved ejection fraction. Together, these findings define a redox-sensitive mitochondrial metabolic state in the HFD/L-NAME model and identify ketone supplementation as a partial metabolic rescue strategy in this context. At the same time, they highlight an important limitation of murine HFpEF models: such models do not faithfully reproduce the metabolic phenotype of human HFpEF and should therefore be interpreted as experimental systems rather than human disease equivalents.

BackgroundSuccinate has emerged as an immunometabolic mediator of cardiovascular diseases. However, the enzymatic mechanisms linking macrophage succinate metabolism to aortic dissection remain incompletely understood. This study investigated whether Suclg2, which encodes the GDP-forming {beta}-subunit of succinyl-CoA ligase, regulates succinate-associated macrophage remodelling and aortic dissection progression. MethodsSuclg2 expression was examined in BAPN-induced AD and human acute type A aortic dissection tissues by Western Blot and immunofluorescence. Myeloid- and smooth muscle cell-specific Suclg2 conditional knockout mice were subjected to BAPN treatment to evaluate survival, aortic outcomes, histological injury and aortic morphology. Aortic RNA-seq was used to discover transcriptional changes. Bone marrow-derived macrophages were analysed under basal, M1-like and M2-like conditions to assess macrophage-intrinsic transcriptional responses. Plasma succinate levels and untargeted metabolomic profiles were further examined. ResultsSuclg2 was increased in murine and human dissected aortas and partially localized to CD68 cells. Myeloid Suclg2 deletion markedly reduced BAPN-induced aortic rupture and dissection, whereas smooth muscle cell Suclg2 deletion did not confer comparable protection. Aortic transcriptomic analysis showed that myeloid Suclg2 deficiency attenuated inflammatory adhesion and matrix-destructive programmes. In macrophages, Suclg2 deletion did not induce a simple M1/M2 polarization shift; instead, it remodelled lipid-handling, phagolysosomal, adhesive and matrix-remodelling pathways across stimulation states. Metabolic profiling showed reduced circulating succinate and broader changes in central carbon, lipid-associated, nucleotide and redox-related metabolites after myeloid Suclg2 deletion. ConclusionsMyeloid Suclg2 is a succinate-associated immunometabolic regulator of aortic dissection. Its deficiency protects against aortic dissection by reshaping macrophage inflammatory-remodelling programmes and the systemic metabolic environment.

Background: Abdominal aortic aneurysms (AAA) are characterized by dilation of the aorta that can lead to aortic rupture and death. The transcriptional co-activators Yes-Associated Protein (YAP) and WW-domain-containing transcriptional co-activator with PDZ-binding motif (TAZ) are mechanosensitive effectors of the highly conserved Hippo signaling pathway. It is hypothesized that cell-specific YAP/TAZ signaling in endothelial cells (EC) plays a pivotal role in mediating AAA formation and rupture. Methods: Single-cell RNA-sequencing in human AAAs was performed and differentially expressed genes (DEGs) were identified in the endothelial cell cluster. YAP/TAZ mRNA and protein expression were also assessed in human AAA and control aortic tissue. Two established murine AAA models were used with male C57BL/6 and EC-CreERT2-YAPfl/fl/TAZfl/fl mice with/without Verteporfin (VPF, YAP/TAZ inhibitor) and XMU-MP-1 (YAP/TAZ activator) treatments. On postoperative days 14 and 28, aortic diameter, histology, cytokine, and MMP2 expressions were evaluated. Results: A significant alteration in EC-specific differentially expressed YAP/TAZ-related genes was observed in which 242 genes were upregulated and 71 genes were downregulated in AAA compared to controls. Human AAA tissue showed a significant increase in YAP and TAZ protein expressions compared to controls. Elastase-treated EC-YAP/TAZ-/- mice showed a significant decrease in AAA diameter compared to littermate controls. Histological quantification revealed preservation of -smooth muscle actin, reduced elastin fiber breaks, and decreased macrophage infiltration in EC-YAP/TAZ-/- mice compared to littermate controls. Importantly, pharmacological inhibition of YAP/TAZ using VPF significantly attenuated AAAs in two experimental murine models. In vitro data demonstrates that VPF inhibits endothelial cell YAP expression, downregulating pathways associated with pathogenic angiogenesis and vascular inflammation. Conclusions: These data suggest that EC-specific YAP/TAZ signaling mediates AAA formation. Pharmacological inhibition of the Hippo pathway can significantly mitigate aortic inflammation and vascular remodeling to decrease the progression of AAAs and prevent aortic rupture.

Background: Thoracic aortopathy is a disorder with genetic influence usually presenting in adulthood for which family screening is potentially desirable. Family screening is recommended, but the predictors of a positive screen and real-world pickup rates are unknown. Methods: This was a retrospective cohort of 1022 probands (first affected family member identified) with thoracic aortopathy and one or more features suggestive of a genetic etiology, and their presenting family members, assessed in a cardiac clinic (2009?2024). Imaging and genetic testing were employed in family screening. The prespecified outcomes were uptake and pickup rate of family screening, and proband and family member specific characteristics that predicted a positive family screen. Results: Among probands, 43.5% had one or more family member screened, with an average of 3 relatives per successful proband. 27.6% of family members screened positive. A pre-existing family history of aortopathy was the only variable predicting a higher incidence rate for positive family screen (p = 0.0003). Age of presentation < 60 was not predictive. For family members, extravascular features (p < 0.0001), closer relation to the proband (p < 0.02), male sex (p < 0.0001) and older age (p< 0.0001) all predicted a positive screen. Family members were eight times more likely to screen positive through imaging as compared to genetic testing. Probands with a genetic diagnosis of Marfan and Loeys Dietz syndromes accounted for only 4% of the total. Conclusions: Proband-initiated family screening for thoracic aortopathy has a high yield of affected individuals, even among older probands.

ObjectiveChronic activation of the renin-angiotensin-aldosterone system (RAAS) promotes pathological remodeling of both myocardium and coronary arteries, yet the mechanisms that distinguish myocardial from vascular remodeling remain poorly defined. This study dissects the relative contributions of hemodynamic versus neurohumoral stress to cardiac remodeling, with emphasis on coronary vasculopathy and vascular smooth muscle cell (VSMC) plasticity. MethodsThree murine models were used: transverse aortic constriction (TAC), angiotensin II (AngII) plus phenylephrine (AngII/PE), and high-dose angiotensin II (HD-AngII). Hemodynamics were assessed by catheterization at early and late time points. Histological and immunostaining analyses quantified interstitial and perivascular remodeling, including cardiomyocyte hypertrophy, interstitial and perivascular fibrosis, VSMC phenotype transitions, proliferation and quiescence markers, and neointimal and elastic lamina remodeling. ResultsAfter 28 days, all models exhibited diastolic dysfunction and myocardial fibrosis. Systolic pressure averaged [~]130 mmHg in both AngII models versus [~]200 mmHg in TAC. Despite lower pressure, myocardial fibrosis was greater in AngII/PE and HD-AngII models. While TAC induced uniform cardiomyocyte hypertrophy, hypertrophy in AngII models localized near fibrotic and perivascular regions. Increasing AngII dosage shifted remodeling from predominantly myocardial to predominantly vascular phenotypes, accompanied by VSMC dedifferentiation, proliferation, centripetal migration across the internal elastic lamina, neointima formation, elastic lamina disruption, and increased circulating desmosine, consistent with elastin degradation. AKT signaling was selectively increased in coronary VSMCs during this vasculopathic remodeling. Lineage-tracing analyses showed that Ang II-driven coronary neointima formation occurs beneath an intact endothelial monolayer and is composed predominantly of VSMC-derived cells, highlighting a VSMC-centric vasculopathy distinct from classic endothelium-initiated vascular remodeling. ConclusionHemodynamic pressure overload and AngII-dominant neurohumoral stress drive distinct cardiac remodeling phenotypes: TAC primarily elicits uniform myocardial hypertrophy and interstitial fibrosis, whereas chronic AngII exposure preferentially promotes a VSMC-centric coronary vasculopathy with perivascular fibrosis and elastic lamina injury at lower pressure load. These complementary models help distinguish pressure-dependent from AngII-mediated vascular mechanisms and provide a platform to develop targeted therapies for coronary vasculopathy and AngII-driven vascular disease. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=129 SRC="FIGDIR/small/733633v1_ufig1.gif" ALT="Figure 1"> View larger version (64K): org.highwire.dtl.DTLVardef@469202org.highwire.dtl.DTLVardef@11bde2borg.highwire.dtl.DTLVardef@96ea08org.highwire.dtl.DTLVardef@1deca16_HPS_FORMAT_FIGEXP M_FIG C_FIG

BackgroundRare heterozygous loss-of-function (LoF) variants in SVIL, encoding the Z-disk and costameric protein supervillin, have recently been identified as a cause of hypertrophic cardiomyopathy (HCM). Although supervillin is implicated in actin-dependent mechanotransduction, the mechanisms linking SVIL deficiency to cardiomyopathy remain poorly understood. Homozygous LoF cause a novel skeletal Myofibrillar Myopathy-10 (MFM-10) while heterozygous LoF cause HCM without skeletal myopathy. In this study we use a human model system to disentangle the LoF pathomechanism of the scaffolding protein supervillin in cardiomyocytes and its clinical implications. MethodsUsing CRISPR/Cas-9 we engineered a representative pathogenic LoF variant Q255X into an isogenic induced pluripotent stem cell (iPSC) line creating the heterozygous SVILQ255X/+ and homozygous SVILQ255X/Q255X cell lines. These lines were differentiated into iPSC-derived cardiomyocytes (iPSC-CMs) and cellular phenotypes were assessed using bulk RNA-sequencing, LC-MS proteomics, electrophysiological and calcium handling analyses, contractility measurements, sarcomere organization analysis, Seahorse metabolic flux assay, and pharmacological intervention with mavacamten. ResultsThe Q255X variant resulted in SVIL haploinsufficiency at both RNA and protein levels with no evidence of a truncated protein. Compared with isogenic controls, SVILQ255X/+ iPSC-CMs demonstrated action potential shortening, calcium transient elongation, sarcomeric disorganization and hypertrophy, and impaired mitochondrial respiration. Multi-omic analyses of SVILQ255X/+ iPSC-CMs showed a profile of cellular stress and inflammation, hypertrophic and pro-fibrotic signalling, and a pseudohypoxic state driven by decreased respiration and a HIF-induced glycolytic shift. These abnormalities were not present in SVILQ255X/Q255X cardiomyocytes, consistent with a relatively limited cardiac phenotype reported in homozygous variant carriers. Mavacamten improved sarcomeric disorganization and hypertrophy in SVILQ255X/+ cells but did not rescue energetic compromise. ConclusionsPathogenic heterozygous SVIL LoF produces a distinct cellular phenotype characterized by impaired mechanotransduction, mitochondrial dysfunction, and maladaptive metabolic remodelling that promotes hypertrophic and pro-fibrotic signalling. These findings define a mechanistic basis for SVIL-associated cardiomyopathy and identify metabolic dysfunction as a potential therapeutic target beyond sarcomere-directed therapy. Clinical PerspectiveO_ST_ABSWhat Is New?C_ST_ABSO_LISVIL haploinsufficiency causes HCM through a mechanism distinct from canonical sarcomeric disease, characterized by impaired mechanotransduction, mitochondrial dysfunction, and pseudohypoxia-driven metabolic remodeling. C_LIO_LIHeterozygous SVIL loss of function produces a substantially more severe cardiomyocyte phenotype than homozygous loss of function, providing a mechanistic explanation for the predominance of cardiac disease in heterozygous variant carriers. C_LIO_LIMavacamten improves sarcomeric organization but does not restore impaired mitochondrial respiration, demonstrating that energetic dysfunction persists despite sarcomere-directed therapy. C_LI What Are the Clinical Implications?O_LIOur findings give functional evidence to support SVIL as a clinically relevant HCM disease gene and its inclusion in clinical genetic testing panels. C_LIO_LIThese findings establish SVIL-associated cardiomyopathy as a mechanistically distinct form of HCM and offer insight into the pathomechanism of Z-disk and costameric HCM C_LIO_LIThe persistence of mitochondrial dysfunction despite myosin inhibition suggests that drugs targeting mitochondrial bioenergetics may be a therapeutic strategy in patients with SVIL-associated cardiomyopathy. C_LI

Background: Heart failure (HF) and body mass index (BMI) share substantial genetic architecture, which may lead genetically informed target discovery to preferentially identify adiposity-related pathways. We sought to identify circulating proteins associated with HF beyond this shared genetic component. Methods: We applied GWAS-by-subtraction to overall HF, nonischemic HF, and nonischemic HF with reduced or preserved ejection fraction to derive BMI-related and BMI-subtracted HF components. We then performed proteome-wide cis-pQTL Mendelian randomization and colocalization using four independent proteomic cohorts, followed by tissue-specific eQTL colocalization, cardiac transcriptomic annotation, and druggability assessment. Results: Compared with the original HF phenotypes, the BMI-subtracted components showed attenuated genetic correlations with BMI (0.045-0.147) while retaining 28 independent loci for overall HF and nine for nonischemic HF. Across 19,930 protein-HF tests, 11 associations involving nine proteins were prioritized by the Mendelian randomization and colocalization analyses. For example, a 1-SD increase in genetically predicted CELSR2 abundance was associated with lower overall HF risk (odds ratio, 0.96 [95% CI, 0.94-0.98]; P=8.6x10-7), whereas a 1-SD increase in genetically predicted CSF3 abundance was associated with higher nonischemic HF risk (odds ratio, 1.32 [95% CI, 1.18-1.48]; P=2.0x10-6). CELSR2 and TMEM106B colocalized with cis-eQTLs in failing left ventricular myocardium, and DAG1 showed cardiomyocyte enrichment with concordant downregulation in failing hearts. Conclusions: We identified nine circulating proteins associated with HF beyond the genetic component shared with BMI. These findings extend the range of genetically supported pathways implicated in HF and nominate candidate proteins for further mechanistic and therapeutic investigation.

Coronavirus disease 2019 (COVID-19), caused by SARS-CoV-2, is associated with significant cardiovascular complications, including myocardial injury and long-term cardiac dysfunction. Individuals with Down syndrome (trisomy 21) exhibit increased susceptibility to severe COVID-19 outcomes, yet the cardiomyocyte-intrinsic mechanisms underlying this vulnerability remain poorly understood. To investigate genotype-specific responses to SARS-CoV-2 infection, we generated induced pluripotent stem cell-derived cardiomyocytes from individuals with trisomy 21 and their euploid, sex-matched biological relatives. Cardiomyocytes were inoculated with SARS-CoV-2, and viral susceptibility was assessed by immunofluorescence. Bulk RNA sequencing was performed under baseline and infected conditions to define transcriptional programs associated with viral response. Trisomy 21 iPSC-CMs exhibited increased susceptibility to SARS-CoV-2 infection, with greater viral protein expression and a higher proportion of infected cardiomyocytes compared to controls. Baseline transcriptomic analysis revealed no significant differences in canonical viral entry factors including ACE2 and TMPRSS2, suggesting that differential susceptibility is not driven by entry receptor availability. Following infection, both trisomy 21 and euploid control groups activated conserved antiviral pathways; however, trisomy 21 cardiomyocytes displayed a markedly amplified transcriptional response, with substantially greater numbers of differentially expressed genes. Upregulated pathways included interferon signaling, NF-{kappa}B activation, cytokine and chemokine signaling, and innate immune responses, while downregulated pathways were enriched for cardiomyocyte structural integrity, calcium handling, and metabolic processes. Notably, inflammatory and cytokine-related transcripts were significantly more elevated in trisomy 21 cells, consistent with an exaggerated immune response. These findings provide mechanistic insight into the increased cardiovascular risk observed in individuals with Down syndrome and highlight dysregulated immune signaling as a potential therapeutic target in this high-risk population.

AimsWhile the muscle-enriched microRNA-378a (miR-378a) has been implicated in cardiac hypertrophy and stress responses, its role in maintaining cardiomyocyte metabolic homeostasis, mitochondrial function, and angiogenic paracrine signaling under physiological and post-injury conditions remains unclear. This study addresses these gaps by examining the molecular and functional consequences of miR-378a deficiency in murine heart and human cardiomyocytes. Methods and ResultsCardiac structure and function were analyzed in miR-378a-deficient (miR-378a-/-) and wild-type (miR-378a+/+) mice at 12 weeks and 17 months of age, revealing that miR-378a loss promoted myocardial fibrosis, altered IGF1R-AKT signaling, and impaired cardiac performance, with age-dependent effects. Integrated transcriptomic and proteomic analyses in miR-378a-/- and control mice, as well as in human iPSC-derived cardiomyocytes (hiPSC-CM) of both genotypes, revealed deregulated pathways related to translation, metabolism, and cardiomyopathy-associated signaling. In hiPSC-CM, miR-378a knockout (KO) impaired mitochondrial respiration, disrupted mitochondrial morphology, and reduced mitochondrial DNA content, accompanied by altered mitophagy and biogenesis. KO cells also showed increased glucose uptake but reduced glycogen storage, accompanied by changes in key metabolic regulators, and displayed diminished angiogenic potential. Finally, hiPSC-CM overexpressing miR-378a were delivered in a mouse model of acute myocardial infarction, but overexpression did not further enhance their therapeutic effect. ConclusionsThis study broadens our understanding of miR-378as physiological role in murine hearts and human cardiomyocytes, demonstrating its impact on contractility, mitochondrial integrity, glucose metabolism, and angiogenic paracrine signaling. However, overexpression of miR-378a in hiPSC-CM offers limited additional benefit in cell therapy for acute myocardial infarction.

Abdominal aortic aneurysms (AAAs) occur predominantly in the elderly population and currently there is no effective pharmacological therapy for mitigating AAA growth and preventing impending rupture. Proprotein subtilisin kexin type 9 (PCSK9) gene has been identified as a specific risk-locus for AAA development. However, the mechanistic and clinical role of PCSK9-mediated signaling in AAAs has not been delineated. We demonstrate that treatment with PCSK9 inhibitors, such as Evolocumab, mitigates vascular inflammation and remodeling, resulting in attenuated aneurysm growth in clinical datasets as well as experimental models of AAA and aortic rupture. Mechanistically, Evolocumab immunomodulates macrophage reprogramming to enhance clearance of apoptotic smooth muscle cells via MerTK-dependent efferocytosis that ameliorates aortic inflammation and vascular remodeling. Furthermore, Evolocumab increases the expression of oxidized phosphatidylserine species and decreases expression of lysophospholipids, succinate, and glycolytic intermediates within the aortic wall compared to untreated controls, further enhancing the pro-resolving functions of macrophages. Collectively, our data demonstrates the ability of PCSK9 inhibition to regulate macrophage-specific efferocytosis that limits AAA progression and prevents aortic rupture.

BackgroundMyocardial ischemia drives adverse cardiac remodeling, metabolic inflexibility, and progression to heart failure. Mitochondrial dysfunction and impaired substrate utilization contribute to cardiomyocyte death and fibrosis, particularly with aging. Humanin (HNG), a mitochondria-derived peptide, has been shown to reduce acute ischemic injury, but its role in chronic ischemia and cardiac remodeling remains unknown. MethodsWe investigated the effects of HNG treatment in young and aged murine models of myocardial ischemia without reperfusion. Cardiac function and structure were assessed by echocardiography and molecular markers of remodeling. Myocardial metabolism was interrogated using targeted metabolomics, gene expression, substrate uptake assays, and metabolic flux analyses. Mechanistic studies examined glucose transporter trafficking and protein-protein interactions. ResultsHNG treatment improved cardiac function and significantly attenuated adverse remodeling in both young and old mice. HNG treatment induced marked metabolic reprogramming characterized by reduced myocardial fatty acid content, downregulation of fatty acid uptake and oxidation pathways, and decreased oxidative stress. Importantly, these changes were accompanied by enhanced glucose oxidation, increased tricarboxylic acid cycle flux, improved coupling of glycolysis to mitochondrial oxidation, and increased ATP production. Time-course studies demonstrated that increased glucose oxidation preceded reductions in fatty acid oxidation, indicating a primary role for glucose metabolism in HNG-mediated cardioprotection. Mechanistically, we identified vesicle-associated membrane protein 7 (VAMP7) as a novel binding partner of HNG, and that this interaction is required for GLUT4 translocation to the plasma membrane and HNG-induced ATP generation. ConclusionsHNG protects the ischemic heart by promoting metabolic reprogramming that shifts substrate utilization from fatty acids to glucose and limiting maladaptive remodeling. These findings identify HNG as a novel regulator of cardiac metabolism and a potential therapeutic strategy for ischemic heart failure. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=65 SRC="FIGDIR/small/732776v1_ufig1.gif" ALT="Figure 1"> View larger version (21K): org.highwire.dtl.DTLVardef@1929de8org.highwire.dtl.DTLVardef@bcf254org.highwire.dtl.DTLVardef@c99b70org.highwire.dtl.DTLVardef@1fc08bb_HPS_FORMAT_FIGEXP M_FIG C_FIG What are the clinical implications?Heart failure (HF) is a major global health concern, affecting over 6.7 million adults in the United States alone, with projections to exceed 11 million by 2050. Myocardial infarction (MI) is a leading cause of HF. Despite substantial advances in acute MI care, survivors remain at high risk for adverse cardiac remodeling and chronic HF, especially in the elderly. We report here that treatment with a potent analog of Humanin (HN), an endogenous mitochondria-associated peptide, decreases infarct size, decreases fibrosis and improves cardiac function following cardiac ischemia induced by permanent ligation of coronary artery in both young and aged mice. These effects are associated with changes in cardiac metabolism, oxidative stress, and remodeling. HN and analogs have been shown to be beneficial in many age-related diseases. The endogenous origin of Humanin, its favorable safety profile in preclinical studies and its pleiotropic effects support targeting HNG as a promising therapeutic strategy for ischemic heart disease and post-myocardial infarction heart failure in humans.

We examined whether polygenic risk for peripheral artery disease (PAD) is associated with severity among patients undergoing lower extremity revascularization at Yale New Haven Hospital. Patients were classified into European (EUR) and non-European (non-EUR) ancestry groups. Associations between the 19-variant polygenic score (PGS) and nine severity indicators were evaluated using linear and Cox regression models stratified by ancestry, followed by meta-analysis. Significant findings (p < 0.05) were assessed for replication in the UK Biobank (UKB). After quality control, 68 EUR and 59 non-EUR patients were included. In EUR patients, higher PGS was associated with increased risk for stroke (HR = 2.43, 95% CI 1.06-5.57). Meta-analysis revealed a significant association between higher PGS and younger age at surgery ({beta} = -2.90, SE = 1.28), which was replicated in the UKB ({beta} = -0.58, SE = 0.15). These results suggest genetic risk contributes to PAD severity.

BackgroundWe previously performed a strain intercross between atherosclerosis resistant AKR Apoe-/-mice and atherosclerosis sensitive DBA/2 Apoe-/- mice and identified the Ath28 quantitative trait locus (QTL) on the distal end of chromosome 2. Congenic strain fine mapping identified the Ath28.1 QTL atherosclerosis modifying subregion, encompassing 217 Kb, containing for only three protein-coding genes, Zbp1, Pck1, and Pmepa1, encoding respectively, Z-DNA binding protein 1, phosphoenolpyruvate carboxykinase 1, and prostate transmembrane protein androgen induced 1. MethodsThe effect of macrophage-specific knockout of Pck1 (KO) was tested using the AAV2 transduced proprotein convertase subtilisin kexin type 9 (PCSK9) overexpression mouse model of hyperlipidemia and atherosclerosis. ResultsUnexpectedly, macrophage Pck1 deficiency lowered body weight, liver weight, and HDL-cholesterol levels in both sexes, while total and non-HDL cholesterol levels were only decreased in male mice. Aortic root lesion area and necrotic lesion area were unchanged in KO mice of both sexes. ConclusionPck1 was not confirmed as an atherosclerosis modifier gene.

BackgroundPulmonary arterial hypertension (PAH) is characterized by circulating metabolic alterations, but whether these reflect disease-specific metabolic programs or reorganization of normal metabolic architecture, and how they relate to right ventricular-pulmonary vascular function (RV-PV), remains unclear. We hypothesized that the PAH metabolome is organized into biologically coherent, co-regulated metabolic modules whose relationships to RV-PV function would provide insight into known and novel metabolic pathways. MethodsWe applied weighted gene co-expression network analysis (WGCNA) to untargeted metabolomic data from 412 PAH patients enrolled in the multicenter PVDOMICS study. Module preservation analysis was performed in 85 healthy controls, with external replication in an independent single-center pulmonary hypertension cohort of 89 patients. ResultsWGCNA identified 16 distinct metabolic modules organized around biologically coherent programs. A coherent fatty acid axis, spanning substrate pools, {beta}-oxidation intermediates, and conjugated fatty acid disposal products, formed a central organizing structure, with downstream fatty acid oxidation modules strongly associated with adverse hemodynamics and worse RV-pulmonary artery (PA) coupling. Acylcholine-enriched and 5-reduced androgen metabolite modules were associated with favorable hemodynamic indices. Module architecture was largely preserved in healthy controls, with subtle disease-associated modular reorganization, rather than emergence of novel modules, observed in PAH. Core modules were recovered in the replication cohort with conserved hub metabolites. ConclusionsThese findings establish a systems-level framework demonstrating that PAH involves structured intensification and reorganization of interconnected metabolic programs associated with favorable and adverse RV-PV phenotypes. This work provides new insight into the metabolic architecture underlying PAH and identifies coordinated metabolic pathways linked to pulmonary vascular and right ventricular function.

Background: Although diabetes is a potent risk factor for the development of peripheral artery disease (PAD), the effect of cumulative metabolic exposure to hyperglycemia on risk of cardiovascular or limb events in patients with PAD remains unclear. Methods: The Peripheral Artery Disease: Long-term Survival (PEARLS) is a longitudinal registry of Veterans with newly diagnosed PAD identified using a natural language processing approach. Included patients had ankle brachial index [&le;]0.9 or toe brachial index [&le;]0.7, and no history of lower extremity revascularization or major amputation. Among patients with diabetes in this cohort, we assessed cumulative exposure to hyperglycema based on a 24-month rolling average of hemoglobin (Hgb) A1c values, categorized as [&le;]7%, >7% to [&le;]8%, and >8%. Multivariable Cox regression models evaluated the association between categories of HgbA1c, modeled as a time-varying exposure, and risk of cardiovascular (CV: myocardial infarction or stroke) and limb (chronic limb threatening ischemia [CLTI] or major amputation) events. Results: Among 45,109 patients with new diagnosis of PAD and pre-existing diabetes, the mean HgbA1c at baseline was 7.5%, with nearly one-third (30.4%) having HgbA1c >8%. The mean age was 70.4 years, 19.8% were Black and 4% were Hispanic. Patients with baseline HgbA1c >8% were younger and compared to those with HgbA1c [&le;]7%, more likely to have coronary disease, kidney disease, and obesity. Over a median follow up of 4.2 years, 8,306 (18.4%) patients experienced a CV event, and 8,199 (18.2%) experienced a limb event. The adjusted association between HgbA1c and hazard of CV events was 12% higher in patients exposed to HgbA1c >7% to [&le;]8% (HR 1.12; 95%CI: 1.05-1.18) and 38% higher in those exposed to HgbA1c >8% (HR 1.38; 95%CI: 1.30-1.46), compared to HgbA1c <7%. The association with limb events was even stronger, with 20% and 60% higher hazard in those exposed to >7% to [&le;]8% (HR 1.20; 95%CI: 1.13-1.28) and HgbA1c >8% (HR 1.60; 95%CI: 1.51-1.70), respectively when compared to HgbA1c [&le;]7%. These findings were consistent in subgroups based on age and severity of PAD. Conclusions: Among diabetic patients with PAD, cumulatiave metabolic exposure to hyperglycemia is associated with a markedly increased risk of clinical events, especially limb events.

Background: Neonatal-onset hypertrophic cardiomyopathy (HCM) is a rare condition with limited data regarding clinical presentation, genetic background, and long-term outcomes. We aimed to characterize the phenotype and prognosis of HCM presenting in neonates. Methods: This is a multicenter retrospective study including patients diagnosed with HCM before 1 year of age. Neonatal-onset HCM was defined as presentation {less than or equal to}28 days of life. Clinical, genetic, instrumental data, treatment, and outcomes were collected. Primary outcome included overall and cardiac survival, major arrhythmic events (MAEs), implantable cardioverter-defibrillator (ICD) implantation, and cardiac surgery. Results: Among 321 pediatric HCM, 21% were diagnosed during infancy and 75% were neonates. Median age at diagnosis was 1 day (IQR 0-6), 82% presented within the first week of life. Prenatal suspicion was in 25%. At presentation, 41% were symptomatic. RASopathies represented the most common etiology (41%), followed by gene-elusive (31%), mitochondrial/inborn errors of metabolism (18%), and sarcomeric (8%). Left ventricular outflow tract obstruction was frequent in sarcomeric and RASopathy. Overall survival was 92% and cardiac survival was 96% at 2 years; long-term survival was 88% at 30 years. ICDs were implanted in 8%; 21% required cardiac surgery. Survival free from ICD was 40% at 15 year and 47% from myectomy. All events occurred in patients presenting within the first weeks of life. Conclusions: Neonatal-onset HCM is characterized by etiologic heterogeneity, predominance of syndromic and non-sarcomeric etiologies, and long-term cardiovascular morbidity. Presentation within the first days of life identifies a high-risk subgroup requiring intensive surveillance and specialized multidisciplinary management.

BackgroundCatecholamines play a central role in cardiac performance, coordinating myocardial contractility, conduction, metabolism, and electrophysiological stability. In the heart, their actions have been attributed primarily to sympathetic nerve terminals and circulating adrenal catecholamines. The discovery of an intrinsic non-neuronal cholinergic system within cardiomyocytes challenges this neurocentric paradigm and raises the possibility that cardiomyocytes also possess an intrinsic catecholaminergic programme. Here, we investigated whether cardiomyocytes possess an intrinsic catecholaminergic programme and its contribution to cardiomyocyte homeostasis and stress responses. MethodsWe investigated catecholamine biosynthesis and handling in human induced pluripotent stem cell-derived cardiomyocytes, adult mouse cardiomyocytes, H9C2 cells, rat ventricular tissue, and Langendorff-perfused mouse hearts. Protein expression of catecholamine biosynthetic enzymes and vesicular monoamine transporters was assessed by immunoblotting and immunohistochemistry, while vesicular monoamine uptake was evaluated using fluorescent false neurotransmitters. Functional consequences of catecholamine biosynthesis inhibition were examined using pharmacological approaches, assessing cell viability, apoptosis, organelle homeostasis, metabolic signalling, and cardiac electrophysiology. ResultsTyrosine hydroxylase, aromatic L-amino acid decarboxylase, dopamine {beta}-hydroxylase, and vesicular monoamine transporters were detected in cardiomyocytes across models. Expression of catecholamine biosynthetic enzymes increased following ischaemia-reperfusion injury in rat heart tissue (TH p=0.008, AADC p=0.031, DBH p=0.008). Pharmacological inhibition of catecholamine biosynthesis caused dose-dependent reductions in cardiomyocyte viability (p<0.0001), increased apoptosis, organelle stress, and mitochondrial dysfunction, with greater effects under oxidative stress. Mechanistically, catecholamine depletion suppressed mTORC1 signalling and activated LKB1-AMPK-ULK1 pathways. In Langendorff-perfused hearts, tyrosine hydroxylase inhibition induced ventricular arrhythmias in 5 of 6 hearts, including sustained ventricular tachycardia, polymorphic ventricular tachycardia, and ventricular fibrillation. ConclusionsThese findings identify cardiomyocytes as previously unrecognised catecholamine-competent cells expressing intrinsic machinery for catecholamine biosynthesis and vesicular handling. Disruption of this pathway compromises metabolic and organelle homeostasis, activates energy-stress and autophagy-related signalling, and promotes malignant ventricular arrhythmias. Intrinsic cardiomyocyte catecholamine biology therefore represents a non-neuronal regulatory axis essential for myocardial resilience and electrical stability, with potential relevance to ischaemic injury and stress-induced dysfunction.

BackgroundNeprilysin (NEP) is a zinc-dependent metalloprotease targeted in heart failure therapy to prevent it degrading circulating cardioprotective vasoactive peptides. NEP can also cleave sarcolipin (SLN), the skeletal- and atrial muscle-specific micropeptide regulator of the sarcoplasmic reticulum Ca2+-ATPase (SERCA). A direct pathophysiological role of NEP in ventricular muscle has not been established. MethodsProteomics and immunoblot analysis of human myocardial specimens were used to quantify NEP abundance in failing and non-failing hearts. Heterologous protein expression and biochemical binding assays assessed NEP-mediated cleavage of phospholamban (PLB) and its impact on PLB-SERCA interactions. Functional consequences of NEP expression or inhibition were evaluated in neonatal rat ventricular myocytes and in a human induced pluripotent stem cell-derived cardiomyocyte (hiPSC-CM) model of heart failure. ResultsWe observed increased NEP abundance in failing human myocardium relative to non-failing controls. We demonstrated that NEP cleaves phospholamban (PLB), disrupting PLB-SERCA interactions. Mutation of PLB (V49A), prevented NEP cleavage and preserved PLB-SERCA binding, indicating V49 is critical for NEP substrate recognition. In neonatal rat ventricular myocytes, NEP expression was associated with faster Ca2+ transient decay kinetics and increased SR Ca2+ load, consistent with reduced SERCA inhibition. Inhibition of NEP in a hiPSC-CM heart failure model attenuated the hypertrophic transcriptional responses and reversed Ca2+-transport dysregulation. ConclusionsThese findings implicate increased NEP expression in the sarcoplasmic reticulum of cardiomyocytes as previously unrecognized maladaptive consequence of heart failure contributing to cardiac dysfunction. In this novel pathophysiological mechanism, increased NEP results in PLB cleavage and loss of regulation of SERCA. While this may relieve SERCA inhibition and augment cellular Ca2+ handling, loss of PLB chronically disrupts hearts dynamic response to adrenergic stress, changing heart rate, or other physiological challenges. The data provide new insight into the cardioprotective effects of pharmacological NEP inhibition in clinical practice, reveal a novel mechanism of action of neprilysin inhibition in cardiomyocytes and may help inform future therapeutic strategies for patients with heart failure. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=118 SRC="FIGDIR/small/732949v1_ufig1.gif" ALT="Figure 1"> View larger version (49K): org.highwire.dtl.DTLVardef@4daf93org.highwire.dtl.DTLVardef@41ef8aorg.highwire.dtl.DTLVardef@d568daorg.highwire.dtl.DTLVardef@d6d213_HPS_FORMAT_FIGEXP M_FIG C_FIG

Background: Approximately 40 million individuals in the US have diabetes, and 6.5 million are also afflicted with congestive heart failure (CHF). This paper outlines the natural history of CHF in T2DM and compares CHF outcomes between patients with and without T2DM. Methods: We performed a retrospective analysis of prospectively collected data from 2,008 patients hospitalized for CHF exacerbation between December 2016 and June 2019. Propensity score matching was used to match diabetics and nondiabetics. Outcomes included survival and readmission rates at 28 d, 3 mo and 6 mo, as well as comparison of echocardiographic findings. Results: A total of 2,008 patients were included. After matching, 492 patients were included, with 244 diabetics and 248 nondiabetics. After matching, readmission rates within 28 days (p=0.625) were not different, but there was a trend for higher readmission rates among diabetics at 3 months (29.3% vs. 21.5%, p=0.049) and 6 months (44.3% vs 35.8%, p=0.053). Echocardiographic characteristics, including LVEF (p=0.135), LV EDV (p=0.707), maximum velocity of mitral valve E wave (p=0.407), maximum velocity of mitral valve A wave (p=0.050), E/A ratio (p=0.501) and tricuspid valve regurgitation pressure (p=0.668) were not different in the two groups. However, tricuspid valve regurgitation velocity was higher in diabetics (3.1 vs 2.9, p=0.003). Conclusions: Although diabetes poses an additional burden for patients with CHF, survival is similar in diabetics and nondiabetics. Nonetheless, readmission rates may be higher among diabetics. Tricuspid return velocity is higher in diabetics, suggesting early pulmonary vasculature remodeling.

Pulmonary arterial hypertension (PAH) is a devastating disease with poor outcome affecting relatively young subjects. The arachidonic acid (AA) metabolite, 15-hydroxyeicosatetraenoic acid (15-HETE), has been implicated in the pathogenesis of hypoxia-induced PAH. We tested the hypothesis that genetic deletion of GPR39, the target receptor for 15-HETE, will attenuate PAH. We subjected wild-type (WT) and GPR39 KO to 4 weeks of hypoxia versus normoxia, after which right ventricular and systemic hemodynamics were measured. Immunohistochemistry of lung was performed for pulmonary arteriolar thickness as well as capillary and pericyte density. Lung tissue was also analyzed for AA and 15-HETE levels as well as signaling events (mRNA and protein levels) downtream of GPR39 activation. Unlike WT mice, GPR39 KO mice did not develop PAH. They also exhibited markedly less pulmonary ateriolar remodeling and greater pulmonary capillary density. mRNA expression of genes in the Gq, Gs and G12/13 pathways were upregulated in the WT mice while GPR39 KO hypoxic showed no change in these genes. WT and not GPR39 KO hypoxic mice exhibited enhanced AKT phosphorylation. Downstream of the phosphatidylinositol 3-kinase-AKT pathway, endothelial nitric oxide synthetase was upregulated in both WT hypoxia and GPR39 KO hypoxia mice, while sonic hedgehog was upregulated only in WT hypoxia mice. We conclude that hypoxia-induced aberrant signaling is markedly attenuated with genetic deletion of GPR39, which is associated with less pulmonary arteriolar remodeling and greater capillary density, thus preventing PAH. These results suggest that pharmacological inhibition of GPR39 may offer a novel treatment for PAH.