BACKGROUND: Heart failure with preserved ejection fraction (HFpEF) has become the most prevalent type of heart failure, but effective treatments are lacking. Cardiac lymphatics play a crucial role in maintaining heart health by draining fluids and immune cells. However, their involvement in HFpEF remains largely unexplored. METHODS: We examined cardiac lymphatic alterations in mice with HFpEF with comorbid obesity and hypertension, and in heart tissues from patients with HFpEF. Using genetically engineered mouse models and various cellular and molecular techniques, we investigated the role of cardiac lymphatics in HFpEF and the underlying mechanisms. RESULTS: In mice with HFpEF, cardiac lymphatics displayed substantial structural and functional anomalies, including decreased lymphatic endothelial cell (LEC) density, vessel fragmentation, reduced branch connections, and impaired capacity to drain fluids and immune cells. LEC numbers and marker expression levels were also decreased in heart tissues from patients with HFpEF. Stimulating lymphangiogenesis with an adeno-associated virus expressing an engineered variant of vascular endothelial growth factor C (VEGFC ^C156S ) that selectively activates vascular endothelial growth factor receptor 3 (VEGFR3) in LECs restored cardiac lymphatic integrity and substantially alleviated HFpEF. Through discovery-driven approaches, defective branched-chain amino acid (BCAA) catabolism was identified as a predominant metabolic signature in HFpEF cardiac LECs. Overexpression of branched-chain ketoacid dehydrogenase kinase (encoded by the Bckdk gene), which inactivates branched-chain ketoacid dehydrogenase (the rate-limiting enzyme in BCAA catabolism), resulted in spontaneous lymphangiogenic defects in LECs. In mice, inducible Bckdk gene deletion in LECs to enhance their BCAA catabolism preserved cardiac lymphatic integrity and protected against HFpEF. BCAA catabolic defects caused ligand-independent phosphorylation of VEGFR3 in the cytoplasm by Src kinase, leading to lysosomal degradation of VEGFR3 instead of its trafficking to the cell membrane. Reduced VEGFR3 availability on the cell surface impeded downstream Akt (protein kinase B) activation, hindered glucose uptake and utilization, and inhibited lymphangiogenesis in LECs with BCAA catabolic defects. CONCLUSIONS: Our study provides evidence that cardiac lymphatic disruption, driven by impaired BCAA catabolism in LECs, is a key factor contributing to HFpEF. These findings unravel the crucial role of BCAA catabolism in modulating lymphatic biology, and suggest that preserving cardiac lymphatic integrity may present a novel therapeutic strategy for HFpEF.

Obstructive sleep apnea (OSA) can aggravate blood pressure and increase the risk of cardiovascular diseases in hypertensive individuals, yet the underlying pathophysiological process is still incompletely understood. More importantly, OSA remains a significantly undiagnosed condition. In this study, a total of 559 hypertensive patients with and without OSA were included. Metabolome and lipidome-wide analyses were performed to explore the pathophysiological processes of hypertension comorbid OSA and derive potential biomarkers for diagnosing OSA in hypertensive subjects. Compared to non-OSA hypertensive patients (discovery set = 120; validation set = 116), patients with OSA (discovery set = 165; validation set = 158) demonstrated a unique sera metabolic phenotype dominated by abnormalities in biological processes of oxidative stress and inflammation. By integrating three machine learning algorithms, six discriminatory metabolites (including 5-hydroxyeicosatetraenoic acid, taurine, histidine, lysophosphatidic acid 16:0, lysophosphatidylcholine 18:0, and dihydrosphingosine) were selected for constructing diagnostic and classified model. Notably, the established multivariate-model could accurately identify OSA subjects. The corresponding area under the curve values and the correct classification rates were 0.995 and 96.8% for discovery sets, 0.997 and 99.1% for validation sets. This work updates the molecular insights of hypertension comorbid OSA and paves the way for the use of metabolomics for the diagnosis of OSA in hypertensive individuals.

BACKGROUND: APN (adiponectin) and APPL1 (adaptor protein, phosphotyrosine interacting with PH domain and leucine zipper 1) are potent vasculoprotective molecules, and their deficiency (eg, hypoadiponectinemia) contributes to diabetic vascular complications. However, the molecular mechanisms that govern their vasculoprotective genes as well as their alteration by diabetes remain unknown. METHODS: Diabetic medium-cultured rat aortic endothelial cells, mouse aortic endothelial cells from high-fat-diet animals, and diabetic human aortic endothelial cells were used for molecular/cellular investigations. The in vivo concept-prove demonstration was conducted using diabetic vascular injury and diabetic hindlimb ischemia models. RESULTS: In vivo animal experiments showed that APN replenishment caused APPL1 nuclear translocation, resulting in an interaction with HDAC (histone deacetylase) 2, which inhibited HDAC2 activity and increased H3Kac27 levels. Based on transcriptionome pathway-specific real-time polymerase chain reaction profiling and bioinformatics analysis, Angpt1 (angiopoietin 1), Ocln (occludin), and Cav1 (caveolin 1) were found to be the top 3 vasculoprotective genes suppressed by diabetes and rescued by APN in an APPL1-dependent manner. APN reverses diabetes-induced inhibition of Cav1 interaction with APPL1. APN-induced Cav1 expression was not affected by Angpt1 or Ocln deficiency, whereas APN-induced APPL1 nuclear translocation or upregulation of Angpt1/Ocln expression was abolished in the absence of Cav1 both in vivo and in vitro, suggesting Cav1 is upstream molecule of Angpt1/Ocln in response to APN administration. Chromatin immunoprecipitation–qPCR (quantitative polymerase chain reaction) demonstrated that APN caused significant enrichment of H3K27ac in Angpt1 and Ocln promoter region, an effect blocked by APPL1/Cav1 knockdown or HDAC2 overexpression. The protective effects of APN on the vascular system were attenuated by overexpression of HDAC2 and abolished by knocking out APPL1 or Cav1. The double knockdown of ANGPT1/OCLN blunted APN vascular protection both in vitro and in vivo. Furthermore, in diabetic human endothelial cells, HDAC2 activity is increased, H3 acetylation is decreased, and ANGPT1/OCLN expression is reduced, suggesting that the findings have important translational implications. CONCLUSIONS: Hypoadiponectinemia and dysregulation of APPL1-mediated epigenetic regulation are novel mechanisms leading to diabetes-induced suppression of vasculoprotective gene expression. Diabetes-induced pathological vascular remodeling may be prevented by interventions promoting APPL1 nuclear translocation and inhibiting HDAC2.

Aim: Intermittent hypoxia (IH) is the prominent feature of obstructive sleep apnea (OSA) pathophysiology, which is an in dependent risk factor of cardiovascular complications. The effects of IH on adipocyte metabolism were explored by high-throughput sequencing technology.Methods: Plasma was collected from OSA patients and control group to perform mRNA sequencing. 3T3-L1 cells were differentiated into adipocytes then subjected to a 5%–21% O₂ hypoxic environment (IH) for 24 h. High-throughput sequencing method was used to determine differential mRNA and miRNA patterns in fat cells exposed to IH. We then performed Gene Ontology (GO) analysis, identified relevant KEGG pathways and miRNA-target-pathways.Results: Sequencing data showed that OSA affected the expression of 343 mRNAs in the plasma. At the same time, we found that IH affected the expression of 3034 mRNAs in the adipocytes. In addition, 68 differentially expressed mRNAs were overlapped in plasma from OSA patient and IH-induced adipocyte model. We observe that 68 differential genes could be connected to 49 reciprocally expressed miRNAs. We showed that IH significantly reduced the expression of miR-182-5p and miR-30c-2-3p. KEGG predicted that the function of expressed miR-182-5p and miR-30c-2-3p was enriched to AKT signaling pathway. Notably, IH activated PI3K/AKT pathway in fat cells.Conclusion: Our results demonstrated that IH might induce adipocyte metabolism by regulating miR-182-5p and miR-30c-2-3p.

Introduction: Diabetes mellitus is a major risk factor for myocardial infarction (MI), yet its molecular mechanisms exacerbating post-MI cardiac remodeling remain unclear.Methods: Type 2 diabetes mellitus mouse model was developed through a high-sugar and high-fat diet (HFD), followed by MI surgery. Four weeks post-surgery, cardiac function was evaluated via echocardiography, and cardiac pathology was examined using Masson's trichrome and wheat germ agglutinin staining. High-throughput sequencing identified differentially expressed mRNAs and long non-coding RNAs (LncRNAs) in diabetic mice with MI. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses, along with LncRNA-target-gene analysis, were performed. Validation in human samples of diabetic patients with STEMI confirmed the influence of HFD on the expression of specific genes.Results: The results demonstrate that diabetes significantly impairs cardiac function, exacerbates cardiac fibrosis and hypertrophy. In addition, our extensive examination of human samples has conclusively demonstrated that diabetes significantly modulates the expression of genes (Rapgef5 and Ing1) within the cardiac tissue of individuals afflicted with STEMI, underscoring the intricate interplay between these conditions. In addition, we have found that Rapgef5 and Ing1 are involved in diabetes-mediated cardiomyocyte apoptosis and proliferation following myocardial infarction.Discussion: Diabetes aggravates post-MI remodeling via Rapgef5/Ing1-mediated apoptosis and proliferation, these findings highlight novel therapeutic targets for diabetic cardiovascular complications.