bims-hafaim Biomed News
on Heart failure metabolism
Issue of 2021‒07‒11
eight papers selected by
Kyle McCommis
Saint Louis University

  1. J Exp Med. 2021 Sep 06. pii: e20210252. [Epub ahead of print]218(9):
      Obesity-induced secretory disorder of adipose tissue-derived factors is important for cardiac damage. However, whether platelet-derived growth factor-D (PDGF-D), a newly identified adipokine, regulates cardiac remodeling in angiotensin II (AngII)-infused obese mice is unclear. Here, we found obesity induced PDGF-D expression in adipose tissue as well as more severe cardiac remodeling compared with control lean mice after AngII infusion. Adipocyte-specific PDGF-D knockout attenuated hypertensive cardiac remodeling in obese mice. Consistently, adipocyte-specific PDGF-D overexpression transgenic mice (PA-Tg) showed exacerbated cardiac remodeling after AngII infusion without high-fat diet treatment. Mechanistic studies indicated that AngII-stimulated macrophages produce urokinase plasminogen activator (uPA) that activates PDGF-D by splicing full-length PDGF-D into the active PDGF-DD. Moreover, bone marrow-specific uPA knockdown decreased active PDGF-DD levels in the heart and improved cardiac remodeling in HFD hypertensive mice. Together, our data provide for the first time a new interaction pattern between macrophage and adipocyte: that macrophage-derived uPA activates adipocyte-secreted PDGF-D, which finally accelerates AngII-induced cardiac remodeling in obese mice.
  2. Front Cardiovasc Med. 2021 ;8 664626
      Cardiac remodeling consisted of ventricular hypertrophy and interstitial fibrosis is the pathological process of many heart diseases. Fibroblasts as one of the major cells in the myocardium regulate the balance of the generation and degeneration of collagen, and these cells transform toward myofibroblasts in pathological state, contributing to the remodeling of the heart. Peroxisome proliferator-activated receptor-γ (PPAR-γ) coactivator-1α (PGC-1α) is vital to the function of mitochondria, which contributes to the energy production and reactive oxidative species (ROS)-scavenging activity in the heart. In this study, we found that fibroblast-specific PGC-1α KO induced cardiac remodeling especially fibrosis, and Angiotensin II (AngII) aggravated cardiac fibrosis, accompanied with a high level of oxidative stress response and inflammation.
    Keywords:  AngII; PGC-1α; cardiac fibroblast; cardiac remodeling; fibrosis
  3. Sci Rep. 2021 Jul 05. 11(1): 13845
      Long-term nicotine intake is associated with an increased risk of myocardial damage and dysfunction. However, it remains unclear whether targeting mitochondrial reactive oxygen species (ROS) prevents nicotine-induced cardiac remodeling and dysfunction. This study investigated the effects of mitoTEMPO (a mitochondria-targeted antioxidant), and resveratrol (a sirtuin activator) , on nicotine-induced cardiac remodeling and dysfunction. Sprague-Dawley rats were administered 0.6 mg/kg nicotine daily with 0.7 mg/kg mitoTEMPO, 8 mg/kg resveratrol, or vehicle alone for 28 days. At the end of the study, rat hearts were collected to analyze the cardiac structure, mitochondrial ROS level, oxidative stress, and inflammation markers. A subset of rat hearts was perfused ex vivo to determine the cardiac function and myocardial susceptibility to ischemia-reperfusion injury. Nicotine administration significantly augmented mitochondrial ROS level, cardiomyocyte hypertrophy, fibrosis, and inflammation in rat hearts. Nicotine administration also induced left ventricular dysfunction, which was worsened by ischemia-reperfusion in isolated rat hearts. MitoTEMPO and resveratrol both significantly attenuated the adverse cardiac remodeling induced by nicotine, as well as the aggravation of postischemic ventricular dysfunction. Findings from this study show that targeting mitochondrial ROS with mitoTEMPO or resveratrol partially attenuates nicotine-induced cardiac remodeling and dysfunction.
  4. J Mol Cell Cardiol. 2021 Jul 02. pii: S0022-2828(21)00135-8. [Epub ahead of print]
      Irisin, the cleaved form of the fibronectin type III domain containing 5 (FNDC5) protein, is involved in metabolism and inflammation. Recent findings indicated that irisin participated in cardiovascular physiology and pathology. In this study, we investigated the effects of FNDC5/irisin on diabetic cardiomyopathy (DCM) in type 2 diabetic db/db mice. Downregulation of myocardial FNDC5/irisin protein expression and plasma irisin levels was observed in db/db mice compared to db/+ controls. Moreover, echocardiography revealed that db/db mice exhibited normal cardiac systolic function and impaired diastolic function. Adverse structural remodeling, including cardiomyocyte apoptosis, myocardial fibrosis, and cardiac hypertrophy were observed in the hearts of db/db mice. Sixteen-week-old db/db mice were intramyocardially injected with adenovirus encoding FNDC5 or treated with recombinant human irisin via a peritoneal implant osmotic pump for 4 weeks. Both overexpression of myocardial FNDC5 and exogenous irisin administration attenuated diastolic dysfunction and cardiac structural remodeling in db/db mice. Results from in vitro studies revealed that FNDC5/irisin protein expression was decreased in high glucose (HG)/high fat (HF)-treated cardiomyocytes. Increased levels of inducible nitric oxide synthase (iNOS), NADPH oxidase 2 (NOX2), 3-nitrotyrosine (3-NT), reactive oxygen species (ROS), and peroxynitrite (ONOO-) in HG/HF-treated H9C2 cells provided evidence of oxidative/nitrosative stress, which was alleviated by treatment with FNDC5/irisin. Moreover, the mitochondria membrane potential (ΔΨm) was decreased and cytochrome C was released from mitochondria with increased levels of cleaved caspase-3 in HG/HF-treated H9C2 cells, indicating the presence of mitochondria-dependent apoptosis, which was partially reversed by FNDC5/irisin treatment. Mechanistic studies showed that activation of integrin αVβ5-AKT signaling and attenuation of oxidative/nitrosative stress were responsible for the cardioprotective effects of FNDC5/irisin. Therefore, FNDC5/irisin mediates cardioprotection in DCM by inhibiting myocardial apoptosis, myocardial fibrosis, and cardiac hypertrophy. These findings implicate that FNDC5/irisin as a potential therapeutic intervention for DCM, especially in type 2 diabetes mellitus (T2DM).
    Keywords:  Diabetic cardiomyopathy; FNDC5; Irisin; Oxidative/nitrosative stress; Type 2 diabetes mellitus
  5. Sheng Li Xue Bao. 2021 Jun 25. 73(3): 459-470
      Cardiac hypertrophy is a common pathological process of various cardiovascular diseases and eventually develops into heart failure. This paper was aimed to study the different pathological characteristics exhibited by different mouse strains after hypertrophy stimulation. Two mouse strains, A/J and FVB/nJ, were treated with isoproterenol (ISO) by osmotic pump to induce cardiac hypertrophy. Echocardiography was performed to monitor heart morphology and function. Mitochondria were isolated from hearts in each group, and oxidative phosphorylation function was assayed in vitro. The results showed that both strains showed a compensatory enhancement of heart contractile function after 1-week ISO treatment. The A/J mice, but not the FVB/nJ mice, developed significant cardiac hypertrophy after 3-week ISO treatment as evidenced by increases in left ventricular posterior wall thickness, heart weight/body weight ratio, cross sectional area of cardiomyocytes and cardiac hypertrophic markers. Interestingly, the heart from A/J mice contained higher mitochondrial DNA copy number compared with that from FVB/nJ mice. Functionally, the mitochondria from A/J mice displayed faster O2 consumption at state III with either complex I substrates or complex II substrate, compared with those from FVB/nJ mice. ISO treatment did not affect mitochondrial respiratory control rate (RCR), but significantly suppressed the ADP/O ratio generated from the complex II substrate in both strains. The ADP/O ratio generated from the complex I substrates in A/J mice declined by 50% after ISO treatment, whereas FVB/nJ mice were not affected. These results suggest that, compared with FVB/nJ mice, A/J mice possesses a poor integrity of mitochondrial respiratory chain that might contribute to its vulnerability to ISO-induced cardiac hypertrophy.
  6. Front Cardiovasc Med. 2021 ;8 683281
      Purpose: The purpose of the study is to evaluate the effect of empagliflozin in patients with heart failure (HF). Method: We performed a systematic search of PubMed, EMBASE, and the Cochrane Library database through January 20, 2021. Randomized controlled trials (RCTs) were included that compared empagliflozin and placebo in patients with HF. Dichotomous variables were expressed as risk ratios (RRs) with 95% confidence intervals (CIs). Continuous variables were calculated and expressed as mean differences (MD) and standard deviation (SD). Meta-analysis was conducted using a random-effects model on outcomes with high heterogeneity. Results: Seven studies were included in our meta-analysis (n = 5,150). Significant differences were observed in a composite of cardiovascular death or hospitalization for worsening heart failure [RR: 0.77 (95% CI 0.68-0.87); I 2 = 18%; P < 0.0001), hospitalization for worsening heart failure [RR: 0.71 (95% CI 0.61-0.82); I 2 = 0%; P < 0.00001], changes in Kansas City Cardiomyopathy Questionnaire (KCCQ) score [MD: 1.70 (95% CI 1.67-1.73); I 2 = 0%; P < 0.00001], and changes in body weight [MD: -1.43 (95% CI -2.15 to -0.72); I 2 = 84%; P < 0.0001) from baseline. However, empagliflozin did not show a better change in the 6-min walk test (6MWT) [MD: 34.06 (95% CI -29.75-97.88); I 2 = 97%; P = 0.30] or NT-proBNP [MD: -98.36 (95% CI, -225.83-29.11); I 2 = 68%; P = 0.13] from baseline. Conclusion: The findings suggest that empagliflozin was effective in reducing a composite of cardiovascular death or hospitalization for worsening heart failure. Further well-designed RCTs are needed to evaluate the long-term effect of empagliflozin in patients with HF. PROSPERO: CRD42021231712.
    Keywords:  cardiovascular; empagliflozin; heart failure; sodium-glucose cotransporter 2 inhibitors; systematic review
  7. Front Cardiovasc Med. 2021 ;8 704462
      Background: The triglyceride-glucose (TyG) index had been proposed as a reliable surrogate marker of insulin resistance. We aimed to evaluate the association between TyG index and myocardial fibrosis, which was quantified by extracellular volume (ECV) fraction using cardiovascular magnetic resonance (CMR) examination, and their prognostic value in patients with heart failure (HF). Methods: In this retrospective cohort study, 103 hospitalized HF patients were included. ECV fraction was calculated using CMR measurements and T1 mapping. TyG index was calculated using fasting triglyceride and blood glucose. The primary outcome events were defined as all-cause mortality and HF hospitalization during follow-up. Results: During the median follow-up of 12.3 months, 39 patients (37.9%) experienced primary outcome events and had higher levels of TyG index, N-terminal pro-B-type natriuretic peptide (NT-proBNP), and ECV fraction compared with those without events. Multivariate linear regression analysis showed that the TyG index was the significant factor determined for ECV fraction (r partial = 0.36, P = 0.01). In multivariate Cox regression analysis, presence of diabetes [hazard ratio (HR) = 1.28, 95% confidence interval (CI) = 1.01-1.62], higher TyG index (HR = 2.01, 95% CI = 1.03-4.01), ECV fraction (HR = 1.73, 95% CI = 1.04-2.88), and NT-proBNP (HR = 2.13, 95% CI = 1.08-4.20) were independent risk factors for the primary outcome events. Conclusions: TyG index is a novel biomarker of myocardial fibrosis in HF patients and can be considered as a useful risk stratification metric in the management of HF.
    Keywords:  biomarkers; heart failure; insulin resistance; myocardial fibrosis; triglyceride-glucose index
  8. J Am Heart Assoc. 2021 Jul 06. e019473
      Background It is known that dietary intake of polyunsaturated fatty acids may improve cardiac function. However, relatively high daily doses are required to achieve sufficient cardiac concentrations of beneficial omega-3 fatty acids. The liver X receptor (LXR) is a nuclear hormone receptor and a crucial regulator of lipid homeostasis in mammals. LXR activation has been shown to endogenously reprogram cellular lipid profiles toward increased polyunsaturated fatty acids levels. Here we studied whether LXR lipid reprogramming occurs in cardiac tissue and exerts cardioprotective actions. Methods and Results Male 129SV mice were treated with the LXR agonist AZ876 (20 µmol/kg per day) for 11 days. From day 6, the mice were injected with the nonselective β-agonist isoproterenol for 4 consecutive days to induce diastolic dysfunction and subendocardial fibrosis while maintaining systolic function. Treatment with isoproterenol led to a marked impairment of global longitudinal strain and the E/e' ratio of transmitral flow to mitral annular velocity, which were both significantly improved by the LXR agonist. Histological examination showed a significant reduction in isoproterenol-induced subendocardial fibrosis by AZ876. Analysis of the cardiac lipid composition by liquid chromatography-high resolution mass spectrometry revealed a significant increase in cardiac polyunsaturated fatty acids levels and a significant reduction in saturated fatty acids by AZ876. Conclusions The present study provides evidence that the LXR agonist AZ876 prevents subendocardial damage, improves global longitudinal strain and E/e' in a mouse model of isoproterenol-induced cardiac damage, accompanied by an upregulation of cardiac polyunsaturated fatty acids levels. Cardiac LXR activation and beneficial endogenous cardiac lipid reprogramming may provide a new therapeutic strategy in cardiac disease with diastolic dysfunction.
    Keywords:  diastolic dysfunction; heart failure; lipids; liver X receptor; nuclear receptor