Metabolic disorder in the progression of heart failure

Inhibition of fatty acid uptake by TGR5 prevents diabetic cardiomyopathy

Diabetic cardiomyopathy is characterized by myocardial lipid accumulation and cardiac dysfunction. Bile acid metabolism is known to play a crucial role in cardiovascular and metabolic diseases. Takeda G-protein-coupled receptor 5 (TGR5), a major bile acid receptor, has been implicated in metabolic regulation and myocardial protection. However, the precise involvement of the bile acid-TGR5 pathway in maintaining cardiometabolic homeostasis remains unclear. Here we show decreased plasma bile acid levels in both male and female participants with diabetic myocardial injury. Additionally, we observe increased myocardial lipid accumulation and cardiac dysfunction in cardiomyocyte-specific TGR5-deleted mice (both male and female) subjected to a high-fat diet and streptozotocin treatment or bred on the diabetic db/db genetic background. Further investigation reveals that TGR5 deletion enhances cardiac fatty acid uptake, resulting in lipid accumulation. Mechanistically, TGR5 deletion promotes localization of CD36 on the plasma membrane through the upregulation of CD36 palmitoylation mediated by the palmitoyl acyltransferase DHHC4. Our findings indicate that the TGR5-DHHC4 pathway regulates cardiac fatty acid uptake, which highlights the therapeutic potential of targeting TGR5 in the management of diabetic cardiomyopathy.

Pathological mechanism of heart failure with preserved ejection fraction in rats based on iTRAQ technology

Objective

Heart failure with preserved ejection fraction (HFpEF) is a public health problem worldwide. Treatments for the patients with HFpEF are not satisfactory because there is no unified understanding of the pathological mechanism of HFpEF. This study aims at investigating the potential pathological mechanism for the effective diagnosis and treatment of HFpEF.

Methods

Ten adult male Dahl salt sensitive rats (180-200 g) were divided into control and model groups. The rats in model group were fed with high salt diet (8% NaCl) to induce HFpEF for this comparative study. Behavioral changes, biochemical parameters, and histopathological changes of the rats were detected. iTRAQ technology combined with bioinformatics analysis was employed to study the differentially expressed proteins (DEPs) and their enrichment in signaling pathways.

Results

Echocardiography detection showed decreased LVEF, indicating impaired cardiac function (P < 0.01), increased LVPWd, indicating ventricular wall hypertrophy (P < 0.05), prolonged duration of IVRT and decreased E/A ratio, indicating diastolic dysfunction (P < 0.05) of the rats in model group. 563 DEPs were identified in the rats of both groups, with 243 up-regulated and 320 down-regulated. The expression of PPAR signaling pathway in the rats of model group was down-regulated, with PPARα most significantly decreased (91.2%) (P < 0.01), PPARγ obviously decreased (63.60%) (P < 0.05), and PPARβ/δ decreased (45.33%) (P < 0.05). The DEPs enriched in PPAR signaling pathway were mainly related to such biological processes as fatty acid beta-oxidation, such cellular components as peroxisome, and such molecular functions as lipid binding.

Conclusions

NaCl high salt diet is one of the factors to increase the incidence of HFpEF in rats. PPARα, PPARγ and PPAR β/δ might be the targets of HFpEF. The findings may provide a theoretical basis for the treatment of HFpEF in clinical practice.

The role of multi-omics in the diagnosis of COVID-19 and the prediction of new therapeutic targets

The global pandemic of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus causing COVID-19, has led to more than 170 million confirmed cases in 223 countries and regions, claiming 3,872,457 lives. Some patients with COVID-19 have mild clinical symptoms despite severe respiratory failure, which greatly increases the difficulty of diagnosis and treatment. It is therefore necessary to identify biological characteristics of SARS-CoV-2, screen novel diagnostic and prognostic biomarkers, as well as to explore potential therapeutic targets for COVID-19. In this comprehensive review, we discuss the current published literature on COVID-19. We find that the comprehensive application of genomics, transcriptomics, proteomics and metabolomics is becoming increasingly important in the treatment of COVID-19. Multi-omics analysis platforms are expected to revolutionize the diagnosis and classification of COVID-19. This review aims to provide a reference for diagnosis, surveillance and clinical decision making related to COVID-19.

Pentraxin 3 in Circulating Microvesicles: a Potential Biomarker for Acute Heart Failure After Cardiac Surgery with Cardiopulmonary Bypass

The aim of this study was to investigate whether pentraxin 3 (PTX3) in microvesicles (MVs) can be a valuable biomarker for the prediction of acute heart failure (AHF) after cardiac surgery with cardiopulmonary bypass (CPB). One hundred and twenty-four patients undergoing cardiac surgery with CPB were included and analyzed (29 with AHF and 95 without AHF). The concentrations of PTX3 in MVs isolated from plasma were measured by ELISA kits before, 12 h, and 3 days after surgery. Patients' demographics, medical history, surgical data, and laboratory results were collected. The levels of PTX3 in MVs were significantly elevated during perioperative surgery, which was increased more in the AHF group. The concentrations of PTX3 in MVs at postoperative 12 h were independent risk factors for AHF with the area under the ROC curve of 0.920. The concentration of PTX3 in MVs may be a novel biomarker for prediction of AHF after cardiac surgery.

NMR-Based Metabolomic Analysis of Sera in Mouse Models of CVB3-Induced Viral Myocarditis and Dilated Cardiomyopathy

Viral myocarditis (VMC) is an inflammatory heart condition which can induce dilated cardiomyopathy (DCM). However, molecular mechanisms underlying the progression of VMC into DCM remain exclusive. Here, we established mouse models of VMC and DCM by infecting male BALB/c mice with Coxsackievirus B3 (CVB3), and performed NMR-based metabonomic analyses of mouse sera. The mouse models covered three pathological stages including: acute VMC (aVMC), chronic VMC (cVMC) and DCM. We recorded ¹D ¹H-NMR spectra on serum samples and conducted multivariate statistical analysis on the NMR data. We found that metabolic profiles of these three pathological stages were distinct from their normal controls (CON), and identified significant metabolites primarily responsible for the metabolic distinctions. We identified significantly disturbed metabolic pathways in the aVMC, cVMC and DCM stages relative to CON, including: taurine and hypotaurine metabolism; pyruvate metabolism; glycine, serine and threonine metabolism; glycerolipid metabolism. Additionally, we identified potential biomarkers for discriminating a VMC, cVMC and DCM from CON including: taurine, valine and acetate for aVMC; glycerol, valine and leucine for cVMC; citrate, glycine and isoleucine for DCM. This work lays the basis for mechanistically understanding the progression from acute VMC to DCM, and is beneficial to exploitation of potential biomarkers for prognosis and diagnosis of heart diseases.

Interplay Between Gut Microbiota and Amino Acid Metabolism in Heart Failure

Heart failure (HF) is a complex clinical syndrome of which the incidence is on the rise worldwide. Cardiometabolic disorders are associated with the deterioration of cardiac function and progression of HF. Recently, there has been renewed interest in gut microbiota (GM) and its metabolites in the cardiovascular disease. HF-caused hypoperfusion could increase intestinal permeability, and a “leaky” bowel leads to bacterial translocation and make its metabolites more easily enter the circulation. Considerable evidence shows that the composition of microbiota and amino acids (AAs) has been altered in HF patients, and AAs could serve as a diagnostic and prognostic biomarker in HF. The findings indicate that the gut–amino acid–HF axis may play a key role in the progression of HF. In this paper, we focus on the interrelationship between the AA metabolism and GM alterations during the development of heart failure. We also discuss the potential prognostic and therapeutic value of the gut–amino acid–HF axis in the cortex of HF.

Metabolomics: small molecules that matter more

Metabolomics, an analytical study with high-throughput profiling, helps to understand interactions within a biological system. Small molecules, called metabolites or metabolomes with the size of <1500 Da, depict the status of a biological system in a different manner. Currently, we are in need to globally analyze the metabolome and the pathways involved in healthy, as well as diseased conditions, for possible therapeutic applications. Metabolome analysis has revealed high-abundance molecules during different conditions such as diet, environmental stress, microbiota, and disease and treatment states. As a result, it is hard to understand the complete and stable network of metabolites of a biological system. This review helps readers know the available techniques to study metabolomics in addition to other major omics such as genomics, transcriptomics, and proteomics. This review also discusses the metabolomics in various pathological conditions and the importance of metabolomics in therapeutic applications.

Compartmentalized β1-adrenergic signalling synchronizes excitation-contraction coupling without modulating individual Ca2+ sparks in healthy and hypertrophied cardiomyocytes

AIMS

β-adrenergic receptors (βARs) play pivotal roles in regulating cardiac excitation-contraction (E-C) coupling. Global signalling of β1ARs up-regulates both the influx of Ca2+ through sarcolemmal L-type Ca2+ channels (LCCs) and the release of Ca2+ from the sarcoplasmic reticulum (SR) through the ryanodine receptors (RyRs). However, we recently found that β2AR stimulation meditates 'offside compartmentalization', confining β1AR signalling into subsarcolemmal nanodomains without reaching SR proteins. In the present study, we aim to investigate the new question, whether and how compartmentalized β1AR signalling regulates cardiac E-C coupling.

METHODS AND RESULTS

By combining confocal Ca2+ imaging and patch-clamp techniques, we investigated the effects of compartmentalized βAR signalling on E-C coupling at both cellular and molecular levels. We found that simultaneous activation of β2 and β1ARs, in contrast to global signalling of β1ARs, modulated neither the amplitude and spatiotemporal properties of Ca2+ sparks nor the kinetics of the RyR response to LCC Ca2+ sparklets. Nevertheless, by up-regulating LCC current, compartmentalized β1AR signalling synchronized RyR Ca2+ release and increased the functional reserve (stability margin) of E-C coupling. In circumstances of briefer excitation durations or lower RyR responsivity, compartmentalized βAR signalling, by increasing the intensity of Ca2+ triggers, helped stabilize the performance of E-C coupling and enhanced the Ca2+ transient amplitude in failing heart cells.

CONCLUSION

Given that compartmentalized βAR signalling can be induced by stress-associated levels of catecholamines, our results revealed an important, yet unappreciated, heart regulation mechanism that is autoadaptive to varied stress conditions.

The cardioprotective effects of the new crystal form of puerarin in isoproterenol-induced myocardial ischemia rats based on metabolomics

Puerarin has shown unique pharmacological effects on myocardial ischemia (MI). Changing the crystal form is an effective approach to improve the cardioprotective effects of puerarin. However, the mechanisms of the new crystal form of puerarin are unclear. In this study, an electrocardiogram, echocardiography, cardiac marker enzymatic activity, oxidative stress indices, and myocardial histology analysis of cardiac tissues were performed to evaluate the cardioprotective effects of the new crystal form of puerarin. Moreover, serum and cardiac tissue metabolomics based on nuclear magnetic resonance (NMR) were used to investigate the potential mechanism of the new crystal form. The results indicated that the new crystal form of puerarin (30 mg/kg) could improve oxidative stress indices, and these improvements were similar to those of the original crystal form of puerarin (120 mg/kg). The new crystal form of puerarin (30 mg/kg) could effectively improve the activities of cardiac marker enzymes, and the improvement effects were better than those of the original crystal form (120 mg/kg). Moreover, metabolomics analysis showed that amino acid metabolism, oxidative stress and energy metabolism were disturbed after MI and could be improved by puerarin. These results demonstrated that the new crystal form of puerarin was effective in treating MI.

Nanobar Array Assay Revealed Complementary Roles of BIN1 Splice Isoforms in Cardiac T-Tubule Morphogenesis

Bridging integrator-1 (BIN1) is a family of banana-shaped molecules implicated in cell membrane tubulation. To understand the curvature sensitivity and functional roles of BIN1 splicing isoforms, we engineered vertical nanobars on a cell culture substrate to create high and low curvatures. When expressed individually, BIN1 isoforms with phosphoinositide-binding motifs (pBIN1) appeared preferentially at high-curvature nanobar ends, agreeing well with their membrane tubulation in cardiomyocytes. In contrast, the ubiquitous BIN1 isoform without phosphoinositide-binding motif (uBIN1) exhibited no affinity to membranes around nanobars but accumulated along Z-lines in cardiomyocytes. Importantly, in pBIN1-uBIN1 coexpression, pBIN1 recruited uBIN1 to high-curvature membranes at nanobar ends, and uBIN1 attached the otherwise messy pBIN1 tubules to Z-lines. The complementary cooperation of BIN1 isoforms (comboBIN1) represents a novel mechanism of T-tubule formation along Z-lines in cardiomyocytes. Dysregulation of BIN1 splicing, e.g., during myocardial infarction, underlied T-tubule disorganization, and correction of uBIN1/pBIN1 stoichiometry rescued T-tubule morphology in heart disease.

Concentration of circulating microparticles: a new biomarker of acute heart failure after cardiac surgery with cardiopulmonary bypass

Acute heart failure (AHF) is a severe complication after cardiac surgery with cardiopulmonary bypass (CPB). Although some AHF biomarkers have been used in clinic, they have limitations when applied in the prediction and diagnosis of AHF after cardiac surgery with CPB, and there are still no effective and specific biomarkers. We and other researchers have shown that circulating microparticles (MPs) increased in a variety of cardiovascular diseases. However, whether the concentration of circulating MPs could be a new biomarker for AHF after cardiac surgery remains unknown. Here, 90 patients undergoing cardiac surgery with CPB and 45 healthy subjects were enrolled. Patients were assigned into AHF (n=14) or non-AHF (n=76) group according to the diagnosis criteria of AHF. The concentrations of circulating MPs were determined before, as well as 12 h and 3 days after operation with nanoparticle tracking analysis technique. MPs concentrations in patients before surgery were significantly higher than those of healthy subjects. Plasma levels of MPs were significantly elevated at 12 h after surgery in patients with AHF, but not in those without AHF, and the circulating MPs concentrations at 12 h after surgery were higher in AHF group compared with non-AHF group. Logistic regression analysis indicated that MPs concentration at postoperative 12 h was an independent risk factor for AHF. The area under receiver operating characteristic curve for MPs concentration at postoperative 12 h was 0.81 and the best cut-off value is 5.20×10⁸ particles mL^-1 with a sensitivity of 93% and a specificity of 10%. These data suggested that the concentration of circulating MPs might be a new biomarker for the occurrence of AHF after cardiac surgery with CPB.

Associations of egg consumption with incident cardiovascular disease and all-cause mortality

Eggs are nutrient-dense while also loaded with abundant cholesterol, thus making the public hesitant about their consumption. We conducted the study to investigate if egg consumption is associated with incident cardiovascular disease (CVD) and all-cause mortality. Using the project of Prediction for Atherosclerotic Cardiovascular Disease Risk in China, we included 102,136 adults free of CVD and assessed their egg consumption with food-frequency questionnaires. CVD endpoints and all-cause mortality were confirmed during follow-ups by interviewing participants or their proxies and checking hospital records/death certificates. The HRs (95% CIs) were calculated using the cohort-stratified Cox regression models. During 777,163 person-years of follow-up, we identified 4,848 incident CVD and 5,511 deaths. U-shaped associations of egg consumption with incident CVD and all-cause mortality were observed. Compared with consumption of 3-<6/week, the multivariable-adjusted HRs (95% CIs) of <1/week and ≥10/week for incident CVD were 1.22 (1.11 to 1.35) and 1.39 (1.28 to 1.52), respectively. The corresponding HRs (95% CIs) for all-cause mortality were 1.29 (1.18 to 1.41) and 1.13 (1.04 to 1.24). Our findings identified that both low and high consumption were associated with increased risk of incident CVD and all-cause mortality, highlighting that moderate egg consumption of 3-<6/week should be recommended for CVD prevention in China.

Protective Effects of Hydrogen on Myocardial Mitochondrial Functions in Septic Mice

Enhancement of mitochondrial physiological function prevents sepsis-induced dysfunction. The present study aimed to elucidate the mechanism by which hydrogen (H2) affects mitochondrial function in a wild-type (WT) and homozygous nuclear factor erythroid 2-related factor 2 (Nrf2) knockout (KO, Nrf2-/-) murine model of sepsis. In myocardial tissues with severe sepsis, H2 gas treatment reduced mitochondrial dysfunction, whereas zinc protoporphyrin (ZnPPIX) negated these beneficial effects. H2 treatment upregulated the protein expression of mitofusin-2 (Mfn2), peroxisome proliferator-activated receptor-gamma coactivator-1α (PGC-1α), and protein heme oxygenase-1 (HO-1) in WT mice with severe sepsis but not in their Nrf2-/- counterparts, and this upregulation was inhibited in the presence of ZnPPIX. In conclusion, the mechanism by which H2 limits organ damage in mice with severe sepsis involves HO-1, whereas the mechanism that limits severe sepsis-related mitochondrial dysfunction involves both HO-1 and Nrf2.