bims-hafaim Biomed News
on Heart failure metabolism
Issue of 2022–05–22
twelve papers selected by
Kyle McCommis, Saint Louis University



  1. Circ Heart Fail. 2022 May 17. 101161CIRCHEARTFAILURE121008758
       BACKGROUND: Type 2 diabetes (T2D) is a high-risk factor for incident of cardiovascular diseases. Women at young ages show a reduced incidence of both T2D and cardiovascular diseases compared with men, but these disparities disappear in postmenopausal women versus age-matched men. Thus, ovaries and ovarian hormones, such as estrogen, are expected to protect from T2D and cardiovascular diseases. In this study, we aimed to investigate the role of ovaries and ovarian hormone estrogen in cardiac function and energy metabolism using the cardiac IRS (insulin receptor substrate) 1 and IRS2 double genes knockout mice that mimic cardiac insulin resistance.
    METHODS: Control and heart-specific IRS1/2 double genes knockout mice were treated with placebo or 17β-estradiol (E2) pellets, respectively, through subcutaneous implantation. Female mice were subjected to a bilateral ovariectomy surgery to remove endogenous E2. The cardiac function and energy metabolism were determined using echocardiography and indirect calorimeter, respectively.
    RESULTS: All male heart-specific IRS1/2 double genes knockout mice died of heart failure at 6 to 8 weeks as we previously described (Qi et al), but all female heart-specific IRS1/2 double genes knockout mice survived >1 year. Removal of ovaries in heart-specific IRS1/2 double genes knockout female mice resulted in cardiac dysfunction, and ultimately animal death. However, E2 supplementation prevented the dilated cardiomyopathy, improved cardiac function and energy metabolism, and enhanced lifespan in both male and ovariectomy female mice deficient for cardiac IRS1 and IRS2 genes, largely owing to the activation of Akt (protein kinase B)-Foxo1 (O1 class of forkhead/winged helix transcription factor) signaling cascades.
    CONCLUSIONS: These results show that estrogen protects mice from cardiac insulin resistance-induced diabetic cardiomyopathy. This may provide a fundamental mechanism for the gender difference for the incidence of both T2D and cardiovascular diseases. This study highlights that estrogen signaling could be a potential target for improving cardiac function and energy metabolism in humans with T2D.
    Keywords:  diabetic cardiomyopathy; energy metabolism; estradiol; estrogen; insulin resistance
    DOI:  https://doi.org/10.1161/CIRCHEARTFAILURE.121.008758
  2. Circ Res. 2022 May 16. 101161CIRCRESAHA122321050
       BACKGROUND: Cellular redox control is maintained by generation of reactive oxygen/nitrogen species balanced by activation of antioxidative pathways. Disruption of redox balance leads to oxidative stress, a central causative event in numerous diseases including heart failure. Redox control in the heart exposed to hemodynamic stress, however, remains to be fully elucidated.
    METHODS: Pressure overload was triggered by transverse aortic constriction in mice. Transcriptomic and metabolomic regulations were evaluated by RNA-sequencing and metabolomics, respectively. Stable isotope tracer labeling experiments were conducted to determine metabolic flux in vitro. Neonatal rat ventricular myocytes and H9c2 cells were used to examine molecular mechanisms.
    RESULTS: We show that production of cardiomyocyte NADPH, a key factor in redox regulation, is decreased in pressure overload-induced heart failure. As a consequence, the level of reduced glutathione is downregulated, a change associated with fibrosis and cardiomyopathy. We report that the pentose phosphate pathway and mitochondrial serine/glycine/folate metabolic signaling, 2 NADPH-generating pathways in the cytosol and mitochondria, respectively, are induced by transverse aortic constriction. We identify ATF4 (activating transcription factor 4) as an upstream transcription factor controlling the expression of multiple enzymes in these 2 pathways. Consistently, joint pathway analysis of transcriptomic and metabolomic data reveals that ATF4 preferably controls oxidative stress and redox-related pathways. Overexpression of ATF4 in neonatal rat ventricular myocytes increases NADPH-producing enzymes whereas silencing of ATF4 decreases their expression. Further, stable isotope tracer experiments reveal that ATF4 overexpression augments metabolic flux within these 2 pathways. In vivo, cardiomyocyte specific deletion of ATF4 exacerbates cardiomyopathy in the setting of transverse aortic constriction and accelerates heart failure development, attributable, at least in part, to an inability to increase the expression of NADPH-generating enzymes.
    CONCLUSIONS: Our findings reveal that ATF4 plays a critical role in the heart under conditions of hemodynamic stress by governing both cytosolic and mitochondrial production of NADPH.
    Keywords:  cell death; fibrosis; glycine; heart failure; metabolomics
    DOI:  https://doi.org/10.1161/CIRCRESAHA.122.321050
  3. J Clin Invest. 2022 May 16. pii: e155333. [Epub ahead of print]132(10):
      In hypertrophied and failing hearts, fuel metabolism is reprogrammed to increase glucose metabolism, especially glycolysis. This metabolic shift favors biosynthetic function at the expense of ATP production. Mechanisms responsible for the switch are poorly understood. We found that inhibitory factor 1 of the mitochondrial FoF1-ATP synthase (ATPIF1), a protein known to inhibit ATP hydrolysis by the reverse function of ATP synthase during ischemia, was significantly upregulated in pathological cardiac hypertrophy induced by pressure overload, myocardial infarction, or α-adrenergic stimulation. Chemical cross-linking mass spectrometry analysis of hearts hypertrophied by pressure overload suggested that increased expression of ATPIF1 promoted the formation of FoF1-ATP synthase nonproductive tetramer. Using ATPIF1 gain- and loss-of-function cell models, we demonstrated that stalled electron flow due to impaired ATP synthase activity triggered mitochondrial ROS generation, which stabilized HIF1α, leading to transcriptional activation of glycolysis. Cardiac-specific deletion of ATPIF1 in mice prevented the metabolic switch and protected against the pathological remodeling during chronic stress. These results uncover a function of ATPIF1 in nonischemic hearts, which gives FoF1-ATP synthase a critical role in metabolic rewiring during the pathological remodeling of the heart.
    Keywords:  Cardiology; Heart failure; Metabolism; Mitochondria; Structural biology
    DOI:  https://doi.org/10.1172/JCI155333
  4. Oxid Med Cell Longev. 2022 ;2022 1122494
      Diabetic cardiomyopathy (DCM) is considered to be a critical contributor to the development of heart failure. Empagliflozin (EMPA), a sodium-glucose cotransporter 2 inhibitor, has been shown to prevent cardiovascular events and reduce the incidence of heart failure in randomized clinical trials. However, the mechanism of how EMPA prevents DCM is poorly understood. To study the potential mechanisms involved in the therapeutic effects of EMPA, we assessed the protective effects of EMPA on myocardial injury in type 2 diabetic db/db mice and H9C2 cardiomyocytes. 9-10-week-old male db/db mice were treated with EMPA (10 mg/kg) via oral gavage daily for 20 weeks. Afterward, cardiac function of treated mice was evaluated by echocardiography, and pathological changes in heart tissues were determined by histopathological examination and western blot assay. EMPA markedly reduced blood glucose levels, improved insulin tolerance, and enhanced insulin sensitivity of db/db mice. In addition, EMPA significantly prevented cardiac dysfunction, inhibited cardiac hypertrophy and fibrosis, and reduced glycogen deposition in heart tissues. Furthermore, EMPA improved diabetes-induced oxidative stress and mitochondrial dysfunction in both heart tissues of db/db mice and palmitate exposed H9C2 cells. EMPA significantly increased the expression of nuclear factor erythroid 2-related factor 2 (Nrf2) and its downstream genetic targets in cardiac tissue of type 2 diabetic db/db mice and H9C2 cells. EMPA also downregulated the expression of mitochondrial fission-related proteins and upregulated the expression of mitochondrial fusion-related proteins. Collectively, these findings indicate that EMPA may prevent DCM via attenuating oxidative stress and improving mitochondrial function in heart tissue.
    DOI:  https://doi.org/10.1155/2022/1122494
  5. Mol Omics. 2022 May 19.
      Empagliflozin (Empa, SGLT2 inhibitor) is widely used in clinical situations for the management of diabetes. It has beneficial effects in reducing cardiac dysfunction and heart failure. However, rare studies have reported the potential mechanisms of Empa reaction. Here, we treated db/db diabetic mice with Empa and collected the heart tissue for metabolomics study. We found that db/db mice showed obvious differences in metabolomics profile compared with db/m mice. Many amino acid metabolism pathways and glycerophospholipids and fatty acyl carnitines were significantly enriched in db/db mice. Detailed analysis revealed the alteration of fatty acid oxidation in db/db mice. Interestingly, many metabolites in the fatty acid oxidation pathway, such as myristoleic acid, 12-hydroxydodecanoic acid, (15-carboxypentadecanoyl)carnitine, decanoylcarnitine, and propionylcarnitine, were significantly rescued by Empa treatment. These results suggest that fatty acid oxidation is one of the targets for Empa treatment in the heart of db/db mice. This study provided new possibilities for the development of therapeutic interventions for diabetic cardiomyopathy.
    DOI:  https://doi.org/10.1039/d2mo00036a
  6. Front Pharmacol. 2022 ;13 870699
      Background: Liquiritin (LQ) is one of the main flavonoids extracted from the roots of Glycyrrhiza spp., which are widely used in traditional Chinese medicine. Studies in both cellular and animal disease models have shown that LQ attenuates or prevents oxidative stress, inflammation, and apoptosis. However, the potential therapeutic effects of LQ on pressure overload-induced cardiac hypertrophy have not been so far explored. Therefore, we investigated the cardioprotective role of LQ and its underlying mechanisms in the aortic banding (AB)-induced cardiac hypertrophy mouse model. Methods and Results: Starting 3 days after AB surgery, LQ (80 mg/kg/day) was administered daily over 4 weeks. Echocardiography and pressure-volume loop analysis indicated that LQ treatment markedly improved hypertrophy-related cardiac dysfunction. Moreover, hematoxylin and eosin, picrosirius red, and TUNEL staining showed that LQ significantly inhibited cardiomyocyte hypertrophy, interstitial fibrosis, and apoptosis. Western blot assays further showed that LQ activated LKB1/AMPKα2/ACC signaling and inhibited mTORC1 phosphorylation in cardiomyocytes. Notably, LQ treatment failed to prevent cardiac dysfunction, hypertrophy, and fibrosis in AMPKα2 knockout (AMPKα2-/-) mice. However, LQ still induced LKB1 phosphorylation in AMPKα2-/- mouse hearts. In vitro experiments further demonstrated that LQ inhibited Ang II-induced hypertrophy in neonatal rat cardiomyocytes (NRCMs) by increasing cAMP levels and PKA activity. Supporting the central involvement of the cAMP/PKA/LKB1/AMPKα2 signaling pathway in the cardioprotective effects of LQ, inhibition of Ang II-induced hypertrophy and induction of LKB1 and AMPKα phosphorylation were no longer observed after inhibiting PKA activity. Conclusion: This study revealed that LQ alleviates pressure overload-induced cardiac hypertrophy in vivo and inhibits Ang II-induced cardiomyocyte hypertrophy in vitro via activating cAMP/PKA/LKB1/AMPKα2 signaling. These findings suggest that LQ might be a valuable adjunct to therapeutic approaches for treating pathological cardiac remodeling.
    Keywords:  AMPKα2; PKA; cAMP; cardiac hypertrophy; heart; liquiritin
    DOI:  https://doi.org/10.3389/fphar.2022.870699
  7. Front Cardiovasc Med. 2022 ;9 858594
      Heart failure caused by pressure overload is one of the leading causes of heart failure worldwide, but its pathological origin remains poorly understood. It remains critical to discover and find new improvements and treatments for pressure overload-induced heart failure. According to previous studies, mitochondrial dysfunction and myocardial interstitial fibrosis are important mechanisms for the development of heart failure. The oligopeptide Szeto-Schiller Compound 31 (SS31) can specifically interact with the inner mitochondrial membrane and affect the integrity of the inner mitochondrial membrane. Whether SS31 alleviates pressure overload-induced heart failure through the regulation of mitochondrial fusion has not yet been confirmed. We established a pressure-overloaded heart failure mouse model through TAC surgery and found that SS31 can significantly improve cardiac function, reduce myocardial interstitial fibrosis, and increase the expression of optic atrophy-associated protein 1 (OPA1), a key protein in mitochondrial fusion. Interestingly, the role of SS31 in improving heart failure and reducing fibrosis is inseparable from the presence of sirtuin3 (Sirt3). We found that in Sirt3KO mice and fibroblasts, the effects of SS31 on improving heart failure and improving fibroblast transdifferentiation were disappeared. Likewise, Sirt3 has direct interactions with proteins critical for mitochondrial fission and fusion. We found that SS31 failed to increase OPA1 expression in both Sirt3KO mice and fibroblasts. Thus, SS31 can alleviate pressure overload-induced heart failure through Sirt3-mediated mitochondrial fusion. This study provides new directions and drug options for the clinical treatment of heart failure caused by pressure overload.
    Keywords:  SS31; Sirt3; heart failure; mitochondrial fusion; myocardial fibroblasts
    DOI:  https://doi.org/10.3389/fcvm.2022.858594
  8. Basic Res Cardiol. 2022 May 17. 117(1): 27
      Major clinical trials with sodium glucose co-transporter-2 inhibitors (SGLT-2i) exhibit protective effects against heart failure events, whereas inconsistencies regarding the cardiovascular death outcomes are observed. Therefore, we aimed to compare the selective SGLT-2i empagliflozin (EMPA), dapagliflozin (DAPA) and ertugliflozin (ERTU) in terms of infarct size (IS) reduction and to reveal the cardioprotective mechanism in healthy non-diabetic mice. C57BL/6 mice randomly received vehicle, EMPA (10 mg/kg/day) and DAPA or ERTU orally at the stoichiometrically equivalent dose (SED) for 7 days. 24 h-glucose urinary excretion was determined to verify SGLT-2 inhibition. IS of the region at risk was measured after 30 min ischemia (I), and 120 min reperfusion (R). In a second series, the ischemic myocardium was collected (10th min of R) for shotgun proteomics and evaluation of the cardioprotective signaling. In a third series, we evaluated the oxidative phosphorylation capacity (OXPHOS) and the mitochondrial fatty acid oxidation capacity by measuring the respiratory rates. Finally, Stattic, the STAT-3 inhibitor and wortmannin were administered in both EMPA and DAPA groups to establish causal relationships in the mechanism of protection. EMPA, DAPA and ERTU at the SED led to similar SGLT-2 inhibition as inferred by the significant increase in glucose excretion. EMPA and DAPA but not ERTU reduced IS. EMPA preserved mitochondrial functionality in complex I&II linked oxidative phosphorylation. EMPA and DAPA treatment led to NF-kB, RISK, STAT-3 activation and the downstream apoptosis reduction coinciding with IS reduction. Stattic and wortmannin attenuated the cardioprotection afforded by EMPA and DAPA. Among several upstream mediators, fibroblast growth factor-2 (FGF-2) and caveolin-3 were increased by EMPA and DAPA treatment. ERTU reduced IS only when given at the double dose of the SED (20 mg/kg/day). Short-term EMPA and DAPA, but not ERTU administration at the SED reduce IS in healthy non-diabetic mice. Cardioprotection is not correlated to SGLT-2 inhibition, is STAT-3 and PI3K dependent and associated with increased FGF-2 and Cav-3 expression.
    Keywords:  Cardioprotection; Dapagliflozin; Empagliflozin; Ertugliflozin; Proteomics; SGLT-2 inhibitors
    DOI:  https://doi.org/10.1007/s00395-022-00934-7
  9. Diabetes. 2022 May 20. pii: db210898. [Epub ahead of print]
      Patients with type 2 diabetes have a substantial risk of developing cardiovascular disease. Phosphodiesterase 4 (PDE4) dysregulation is of pathophysiological importance in metabolic disorders. To determine the role of PDE4 in diabetic cardiac dysfunction, mice fed with high-fat diet (HFD) were treated by pharmacological inhibition of PDE4 or cardiac specific knocking down of PDE4D. Mice on HFD developed diabetes and cardiac dysfunction with increased cardiac PDE4D5 expression. PDE4 inhibitor roflumilast can reverse hyperglycemia and cardiac dysfunction, accompanied by the decrease of PDE4D expression and increase of muscle-specific microRNA miR-1 level in hearts. Either cardiac specific PDE4D knockdown or miR-1 overexpression significantly reversed cardiac dysfunction in HFD-mice, despite persistence of hyperglycemia. Gain- and loss-of-function studies of PDE4D in cardiomyocytes implicated that inhibition of insulin-induced PDE4D protected cardiac hypertrophy by preserving miR-1 expression in cardiomyocytes through promoting cAMP-CREB-Sirt1 signaling-induced SERCA2a expression. We further revealed that insulin also induced PDE4D expression in cardiac fibroblasts, which causes cardiac fibrosis through TGF-β1 signaling-mediated miR-1 reduction. Importantly, the expression of PDE4D5 was increased in human failing hearts with diabetes. These studies elucidate a novel mechanism by which hyperinsulinemia-induced cardiac PDE4D expression contributes to diabetic cardiac remodeling through reducing the expression of miR-1 and upregulation of miR-1 target hypertrophy and fibrosis-associated genes. Our study suggests a therapeutic potential of PDE4 inhibitor roflumilast in preventing or treating cardiac dysfunction in diabetes in addition to lowering glucose.
    DOI:  https://doi.org/10.2337/db21-0898
  10. Cardiovasc Diabetol. 2022 May 15. 21(1): 77
       BACKGROUND: The inflammatory response occurring in acute myocardial infarction (AMI) has been proposed as a potential pharmacological target. Sodium-glucose co-transporter 2 inhibitors (SGLT2-I) currently receive intense clinical interest in patients with and without diabetes mellitus (DM) for their pleiotropic beneficial effects. We tested the hypothesis that SGLT2-I have anti-inflammatory effects along with glucose-lowering properties. Therefore, we investigated the link between stress hyperglycemia, inflammatory burden, and infarct size in a cohort of type 2 diabetic patients presenting with AMI treated with SGLT2-I versus other oral anti-diabetic (OAD) agents.
    METHODS: In this multicenter international observational registry, consecutive diabetic AMI patients undergoing percutaneous coronary intervention (PCI) between 2018 and 2021 were enrolled. Based on the presence of anti-diabetic therapy at the admission, patients were divided into those receiving SGLT2-I (SGLT-I users) versus other OAD agents (non-SGLT2-I users). The following inflammatory markers were evaluated at different time points: white-blood-cell count, neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), neutrophil-to-platelet ratio (NPR), and C-reactive protein. Infarct size was assessed by echocardiography and by peak troponin levels.
    RESULTS: The study population consisted of 583 AMI patients (with or without ST-segment elevation): 98 SGLT2-I users and 485 non-SGLT-I users. Hyperglycemia at admission was less prevalent in the SGLT2-I group. Smaller infarct size was observed in patients treated with SGLT2-I compared to non-SGLT2-I group. On admission and at 24 h, inflammatory indices were significantly higher in non-SGLT2-I users compared to SGLT2-I patients, with a significant increase in neutrophil levels at 24 h. At multivariable analysis, the use of SGLT2-I was a significant predictor of reduced inflammatory response (OR 0.457, 95% CI 0.275-0.758, p = 0.002), independently of age, admission creatinine values, and admission glycemia. Conversely, peak troponin values and NSTEMI occurrence were independent predictors of a higher inflammatory status.
    CONCLUSIONS: Type 2 diabetic AMI patients receiving SGLT2-I exhibited significantly reduced inflammatory response and smaller infarct size compared to those receiving other OAD agents, independently of glucose-metabolic control. Our findings are hypothesis generating and provide new insights on the cardioprotective effects of SGLT2-I in the setting of coronary artery disease.
    TRIAL REGISTRATION: Data are part of the ongoing observational registry: SGLT2-I AMI PROTECT.
    CLINICALTRIALS: gov Identifier: NCT05261867.
    Keywords:  Acute myocardial infarction; Hyperglycemia; Infarct size; Inflammation; SGLT2-I
    DOI:  https://doi.org/10.1186/s12933-022-01506-8
  11. World J Cardiol. 2022 Apr 26. 14(4): 266-270
      Diabetes mellitus (DM) is a health condition characterized by glucose dysregulation and affects millions of people worldwide. The presentation of heart failure in diabetic cardiomyopathy extends over a wide phenotypic spectrum, commencing from asymptomatic, subclinical structural abnormalities to severely symptomatic biventricular dysfunction with increased mortality risk. Similarly, the spectrum of systolic dysfunction in diabetic-induced heart failure is diverse. DM leads also to cardiac electrical remodeling reacting on various targets. Dipeptidyl peptidase-4 (DPP-4) inhibitors reduce glucagon and blood glucose levels by raising levels of the endogenous hormones glucagon-like-peptide 1 and glucose-dependent insulinotropic peptide and constitute a safe and effective glucose lowering treatment option in patients with type 2 DM. Despite DPP-4 inhibitors' efficacy regarding glycemic control, their effect on cardiovascular outcomes (myocardial infarction, stroke, hospitalization for heart failure, hospitalization for unstable angina, hospitalization for coronary revascularization, and cardiovascular death) in diabetic patients has been neutral. The potential correlation between atrial flutter and DPP-4 inhibitors administration needs further investigation.
    Keywords:  Atrial flutter; Diabetes mellitus; Dipeptidyl peptidase-4 inhibitors; Heart failure; Meta-analysis; Outcomes
    DOI:  https://doi.org/10.4330/wjc.v14.i4.266
  12. Cardiovasc Diabetol. 2022 May 18. 21(1): 67
       BACKGROUND: There have been scarce data comparing cardiovascular outcomes between individual sodium-glucose cotransporter-2 (SGLT2) inhibitors. We aimed to compare the subsequent cardiovascular risk between individual SGLT2 inhibitors.
    METHODS: We analyzed 25,315 patients with diabetes mellitus (DM) newly taking SGLT2 inhibitors (empagliflozin: 5302, dapagliflozin: 4681, canagliflozin: 4411, other SGLT2 inhibitors: 10,921). We compared the risks of developing heart failure (HF), myocardial infarction (MI), angina pectoris (AP), stroke, and atrial fibrillation (AF) between individual SGLT2 inhibitors.
    RESULTS: Median age was 52 years, and 82.5% were men. The median fasting plasma glucose and HbA1c levels were 149 (Q1-Q3:127-182) mg/dL and 7.5 (Q1-Q3:6.9-8.6) %. During a mean follow-up of 814 ± 591 days, 855 HF, 143 MI, 815 AP, 340 stroke, and 139 AF events were recorded. Compared with empagliflozin, the risk of developing HF, MI, AP, stroke, and AF was not significantly different in dapagliflozin, canagliflozin, and other SGLT inhibitors. For developing HF, compared with empagliflozin, hazard ratios of dapagliflozin, canagliflozin, and other SGLT2 inhibitors were 1.02 (95% confidence interval [CI] 0.81-1.27), 1.08 (95% CI 0.87-1.35), and 0.88 (95% CI 0.73-1.07), respectively. Wald tests showed that there was no significant difference in the risk of developing HF, MI, AP, stroke, and AF among individual SGLT2 inhibitors. We confirmed the robustness of these results through a multitude of sensitivity analyses.
    CONCLUSION: The risks for subsequent development of HF, MI, AP, stroke, and AF were comparable between individual SGLT2 inhibitors. This is the first study comparing the wide-range cardiovascular outcomes of patients with DM treated with individual SGLT2 inhibitors using large-scale real-world data.
    Keywords:  Cardiovascular disease; Diabetes mellitus; SGLT2 inhibitor
    DOI:  https://doi.org/10.1186/s12933-022-01508-6