α-Ketoglutarate improves cardiac insufficiency through NAD+-SIRT1 signaling-mediated mitophagy and ferroptosis in pressure overload-induced mice.

BACKGROUND: In heart failure (HF), mitochondrial dysfunction and metabolic remodeling lead to a reduction in energy productivity and aggravate cardiomyocyte injury. Supplementation with α-ketoglutarate (AKG) alleviated myocardial hypertrophy and fibrosis in mice with HF and improved cardiac insufficiency. However, the myocardial protective mechanism of AKG remains unclear. We verified the hypothesis that AKG improves mitochondrial function by upregulating NAD+ levels and activating silent information regulator 2 homolog 1 (SIRT1) in cardiomyocytes. METHODS: In vivo, 2% AKG was added to the drinking water of mice undergoing transverse aortic constriction (TAC) surgery. Echocardiography and biopsy were performed to evaluate cardiac function and pathological changes. Myocardial metabolomics was analyzed by liquid chromatography‒mass spectrometry (LC‒MS/MS) at 8 weeks after surgery. In vitro, the expression of SIRT1 or PINK1 proteins was inhibited by selective inhibitors and siRNA in cardiomyocytes stimulated with angiotensin II (AngII) and AKG. NAD+ levels were detected using an NAD test kit. Mitophagy and ferroptosis levels were evaluated by Western blotting, qPCR, JC-1 staining and lipid peroxidation analysis. RESULTS: AKG supplementation after TAC surgery could alleviate myocardial hypertrophy and fibrosis and improve cardiac function in mice. Metabolites of the malate-aspartate shuttle (MAS) were increased, but the TCA cycle and fatty acid metabolism pathway could be inhibited in the myocardium of TAC mice after AKG supplementation. Decreased NAD+ levels and SIRT1 protein expression were observed in heart of mice and AngII-treated cardiomyocytes. After AKG treatment, these changes were reversed, and increased mitophagy, inhibited ferroptosis, and alleviated damage in cardiomyocytes were observed. When the expression of SIRT1 was inhibited by a selective inhibitor and siRNA, the protective effect of AKG was suppressed. CONCLUSION: Supplementation with AKG can improve myocardial hypertrophy, fibrosis and chronic cardiac insufficiency caused by pressure overload. By increasing the level of NAD+, the SIRT-PINK1 and SIRT1-GPX4 signaling pathways are activated to promote mitophagy and inhibit ferroptosis in cardiomyocytes, which ultimately alleviates cardiomyocyte damage.

Exploration on Syndrome Types and Metabolic Markers of Rat Model with Heart Failure Caused by Transverse Aortic Constriction Based on Theory of Correspondence of Prescription and Syndrome / 中国实验方剂学杂志

ObjectiveTo observe the difference in the efficacy of three kinds of traditional Chinese medicine （TCM） injections on rat model of heart failure induced by transverse aortic constriction （TAC）， explore the TCM syndrome of the model based on the theory of correspondence of prescription and syndrome， and reveal the biological basis of prescription-syndrome from the perspective of metabolism. MethodRats were treated with TAC for modeling and were divided into Shenmai injection group （6.0 mL·kg-1）， model group， Danhong injection group （6.0 mL·kg-1）， Shenfu injection group （6.0 mL·kg-1） and trimetazidine group （10 mg·kg-1）， and sham operation group was set up as control. After drug intervention for 15 days， echocardiography， serum N-terminal pro-brain natriuretic peptide （NT-proBNP） and myocardial histopathological staining were performed for each group， so as to compare the efficacy to select the effective injection. Colorimetry was used to detect the serum glucolipid metabolism after the intervention of the effective injection， and ultra high performance liquid chromatography-mass spectrometry was used to observe the metabolites and related metabolic pathways in myocardial tissue. ResultCompared with the sham operation group， the left ventricular ejection fraction （LVEF） and left ventricular fractional shortening （FS） in the model group decreased （P<0.01）， while the left ventricular end-diastolic diameter （LVIDd）， left ventricular internal diameter at end-systole （LVIDs） and NT-proBNP level increased （P<0.01）. Compared with model group， LVEF and FS increased （P<0.01）， LVIDd， LVIDs and NT-proBNP level decreased （P<0.05， P<0.01） in Danhong injection group， NT-proBNP level in Shenfu injection group decreased （P<0.05）， LVIDd and NT-proBNP level increased （P<0.05， P<0.01） in Shenmai injection group， in trimetazidine group， LVEF and FS increased （P<0.01）， while LVIDs and NT-proBNP level decreased （P<0.05， P<0.01）. Serum glucose， low-density lipoprotein cholesterol and high-density lipoprotein cholesterol levels in Danhong injection group and trimetazidine group were adjusted by callbacks （P<0.01， P<0.05）. There were the callback of 9 myocardial metabolites in Danhong injection group， including glycine， serine and threonine metabolism， glyoxylate and dicarboxylate metabolism， glycerol phospholipid metabolism. There were the callback of 10 myocardial metabolites in trimetazidine group， including glycerol phospholipid metabolism. ConclusionThe efficacy of Danhong injection on heart failure model induced by TAC is significant and superior to Shenfu injection and Shenmai injection， suggesting that the model is closely related to heart-blood stasis. The biological mechanism of Danhong injection interfering with the model involves regulating the metabolic disorder of lipid， glucose， amino acid and butyric acid.

Alpha-ketoglutarate ameliorates pressure overload-induced chronic cardiac dysfunction in mice.

Increasing evidence indicates the involvement of myocardial oxidative injury and mitochondrial dysfunction in the pathophysiology of heart failure (HF). Alpha-ketoglutarate (AKG) is an intermediate metabolite of the tricarboxylic acid (TCA) cycle that participates in different cellular metabolic and regulatory pathways. The circulating concentration of AKG was found to decrease with ageing and is elevated after acute exercise and resistance exercise and in HF. Recent studies in experimental models have shown that dietary AKG reduces reactive oxygen species (ROS) production and systemic inflammatory cytokine levels, regulates metabolism, extends lifespan and delays the occurrence of age-related decline. However, the effects of AKG on HF remain unclear. In the present study, we explored the effects of AKG on left ventricular (LV) systolic function, the myocardial ROS content and mitophagy in mice with transverse aortic constriction (TAC). AKG supplementation inhibited pressure overload-induced myocardial hypertrophy and fibrosis and improved cardiac systolic dysfunction; in vitro, AKG decreased the Ang II-induced upregulation of ß-MHC and ANP, reduced ROS production and cardiomyocyte apoptosis, and repaired Ang II-mediated injury to the mitochondrial membrane potential (MMP). These benefits of AKG in the TAC mice may have been obtained by enhanced mitophagy, which cleared damaged mitochondria. In summary, our study suggests that AKG improves myocardial hypertrophy remodelling, fibrosis and LV systolic dysfunction in the pressure-overloaded heart by promoting mitophagy to clear damaged mitochondria and reduce ROS production; thus, AKG may have therapeutic potential for HF.

Hirsutella sinensis fungus improves cardiac function in mouse model of heart failure.

Cordyceps sinensis, including Hirsutella sinensis, is a highly valuable traditional Chinese medicine and is used to treat patients with pulmonary heart disease in clinical practice. However, the underlying mechanisms of its effects remain unclear. In this study, a mouse model of heart failure established by non-thoracic, transverse aortic constriction (TAC) was developed to determine the underlying mechanisms of therapeutic effects of Hirsutella sinensis fungus (HSF) powder. The results showed that HSF treatment remarkably ameliorated myocardial hypertrophy, collagen fiber hyperplasia, and cardiac function in mice with heart failure. Using transcriptional and epigenetic analyses, we found that the mechanism of HSF mainly involved a variety of signaling pathways related to myocardial fibrosis and determined that HSF could reduce the levels of TGF-ß1 proteins in heart tissue, as well as type I and III collagen levels. These data suggest that HSF alleviates heart failure, inhibits irreversible ventricular remodeling, and improves cardiac function through the regulation of myocardial fibrosis-related signaling pathways, which can provide novel opportunities to improve heart failure therapy.

The effect of Guanxin Shutong capsule on alleviating the myocardial fibrosis in heart failure rats.

ETHNOPHARMACOLOGICAL RELEVANCE: Guanxin Shutong (GXST) capsule is a renowned traditional Chinese medicine widely used for the treatment of cardiovascular diseases in the clinic. However, no pharmacological experimental studies of GXST has been reported on the treatment of pressure overload-induced heart failure. This study aimed to investigate the effects of GXST capsule on ameliorating myocardial fibrosis conditions in pressure overload-induced heart failure rats. MATERIAL AND METHODS: Rats were randomly divided into 6 groups: Normal group, Model group, GXST-treated group at a dose of 0.5 g/kg, 1 g/kg, 2 g/kg, respectively, and digoxin positive control group at a dose of 1 mg/kg. After 4 weeks of administration, cardiac function was evaluated by echocardiography. Cardiac injury and fibrotic conditions were evaluated by H&E staining, Masson staining, and Sirius Red staining. Myocardial fibrosis was evaluated by immunohistochemistry staining and Western blot. RESULTS: GXST significantly inhibited cardiac fibrosis, reduced the excessive deposition of collagen, and finally improved cardiac function. GXST reversed ventricular remodeling might be through the TGF-ß/Smad3 pathway. CONCLUSION: GXST capsule demonstrated a strong anti-fibrosis effect in heart failure rats by inhibiting the TGF-ß/Smad3 signaling pathway.

Experimental model of congestive heart failure induced by transverse aortic constriction in BALB/c mice.

INTRODUCTION: Murine transverse aortic constriction (TAC) is a frequently used model of pressure overload-induced left ventricular (LV) remodeling. However, there is considerable variability in disease progression to overt heart failure (HF) development in the most commonly used strain of mice (i.e., C57BL/6J). Studies have shown that C57BL/6J mice are more resistant than BALB/c mice to congestive HF development following myocardial infarction or angiotensin II-induced hypertension. Therefore, we tested the hypothesis that BALB/c mice may be a better research model to study TAC-induced progressive HF. METHODS: Following sham or TAC surgery in both C57BL/6J (n = 29) and BALB/c (n = 32) mice, we evaluated cardiac dimensions and function by echocardiography at 2, 4, 8, and 12 weeks and monitored survival throughout the study. In a separate cohort of BALB/c mice, we repeated the study in the presence of the angiotensin converting enzyme inhibitor enalapril or a vehicle initiated 2 weeks post-TAC and administered for 6 weeks. At the end of the studies, we assessed the heart weight, lung weight, and plasma brain natriuretic peptide (BNP) concentration. RESULTS: Following comparable TAC, both C57BL/6J and BALB/c mice showed significant LV remodeling compared with the sham control mice. BALB/c mice progressively developed systolic dysfunction, LV dilation, lung congestion, and significant mortality, whereas C57BL/6J mice did not. In the separate cohort of BALB/c TAC mice, enalapril significantly reduced the heart weight, lung weight, and plasma BNP concentration and improved survival compared with the vehicle control. DISCUSSION: BALB/c mice uniformly developed congestive HF post-TAC. Enalapril was effective in improving survival and reducing lung congestion in this model. The data suggest that BALB/c mice may be a better research tool than C57BL/6J mice to study TAC-induced disease progression to HF and to evaluate novel therapies for the treatment of chronic HF with reduced ejection fraction.

Blueberry anthocyanin­enriched extract ameliorates transverse aortic constriction­induced myocardial dysfunction via the DDAH1/ADMA/NO signaling pathway in mice.

Blueberry anthocyanin­enriched extract (BAE) has been demonstrated to protect against cardiovascular diseases by activating multiple target genes. The present study investigated the effects of BAE on transverse aortic constriction (TAC)­induced myocardial dysfunction in mice and explored its possible molecular mechanisms. A total of 30 male mice were divided randomly into control, TAC and TAC + BAE groups. Mice in the TAC + BAE groups were administered BAE by oral gavage for 6 consecutive weeks. Myocardial dysfunction was assessed using echocardiogram, histopathology, TUNEL assay, immunofluorescence staining, reverse transcription­quantitative PCR and western blot analysis. The results demonstrated that BAE treatment significantly ameliorated heart weight, left ventricular weight, myocardial dysfunction, left ventricular hypertrophy and fibrosis. In addition, BAE treatment alleviated TAC­induced inflammation, oxidative stress and apoptosis. Notably, BAE treatment markedly reduced asymmetric dimethylarginine (ADMA) concentration and significantly increased dimethylarginine dimethylaminohydrolase 1 (DDAH1) expression and nitric oxide (NO) production. The present data indicated that BAE treatment ameliorated TAC­induced myocardial dysfunction, oxidative stress, inflammatory response and apoptosis via the DDAH1/ADMA/NO signaling pathway.

BAOXIN Granules Protected Mouse Model With Elevated Afterload From Cardiac Hypertrophy by Suppressing Both Inflammatory Reaction and Collagen Deposition.

BAOXIN Pill was reported to be effective clinically for chronic heart failure based on the principles of traditional Chinese medicine (TCM), invigorating qi and activating blood. The present study evaluated preclinically the effects of the improved dosage form, BAOXIN Granules, on cardiac hypertrophy. Transverse aortic constriction (TAC) was performed in mice to model cardiac hypertrophy by aortic stenosis for 4 weeks. The sham and TAC group were intragastrically administrated with saline as the controls. Two treatment groups were administrated orally with 10 mg/kg⋅d Enalapril (positive control) or 0.77 g/kg⋅d BAOXIN Granules for 4 weeks respectively. The effects were evaluated by echocardiography, morphology, and biological markers for cardiac function. The specific genes involved in inflammation and fibrosis were also examined for their expressions to investigate the pathways involved in early heart failure. Just as Enalapril, BAOXIN Granules administration markedly attenuated left ventricular hypertrophy and improved heart function as evidenced by echo cardiography, morphology. Accordingly, the biomarkers of the early stage heart failure, ANP, BNP and ß-MHC, were decreased in the two treatment groups. We also found that mRNA expressions of some inflammatory factors and fibrosis associated genes were down-regulated in the tissue of heart after treatment. BAOXIN Granules may protect the heart from myocardial hypertrophy caused by increasing left ventricular afterload. It can suppress both inflammatory reaction and collagen deposition during pressure overload. BAOXIN Granules is advised to be tested in clinical trials for heart failure in the future.

Melatonin protects against the pathological cardiac hypertrophy induced by transverse aortic constriction through activating PGC-1ß: In vivo and in vitro studies.

Melatonin, a circadian molecule secreted by the pineal gland, confers a protective role against cardiac hypertrophy induced by hyperthyroidism, chronic hypoxia, and isoproterenol. However, its role against pressure overload-induced cardiac hypertrophy and the underlying mechanisms remains elusive. In this study, we investigated the pharmacological effects of melatonin on pathological cardiac hypertrophy induced by transverse aortic constriction (TAC). Male C57BL/6 mice underwent TAC or sham surgery at day 0 and were then treated with melatonin (20 mg/kg/day, via drinking water) for 4 or 8 weeks. The 8-week survival rate following TAC surgery was significantly increased by melatonin. Melatonin treatment for 8 weeks markedly ameliorated cardiac hypertrophy. Compared with the TAC group, melatonin treatment for both 4 and 8 weeks reduced pulmonary congestion, upregulated the expression level of α-myosin heavy chain, downregulated the expression level of ß-myosin heavy chain and atrial natriuretic peptide, and attenuated the degree of cardiac fibrosis. In addition, melatonin treatment slowed the deterioration of cardiac contractile function caused by pressure overload. These effects of melatonin were accompanied by a significant upregulation in the expression of peroxisome proliferator-activated receptor-gamma co-activator-1 beta (PGC-1ß) and the inhibition of oxidative stress. In vitro studies showed that melatonin also protects against angiotensin II-induced cardiomyocyte hypertrophy and oxidative stress, which were largely abolished by knocking down the expression of PGC-1ß using small interfering RNA. In summary, our results demonstrate that melatonin protects against pathological cardiac hypertrophy induced by pressure overload through activating PGC-1ß.

Velvet antler peptide prevents pressure overload-induced cardiac fibrosis via transforming growth factor (TGF)-ß1 pathway inhibition.

Velvet antlers (VAs) are commonly used in traditional Chinese medicine and invigorant and contain many functional components for health promotion. The velvet antler peptide sVAP32 is one of active components in VAs; based on structural study, the sVAP32 interacts with TGF-ß1 receptors and disrupts the TGF-ß1 pathway. We hypothesized that sVAP32 prevents cardiac fibrosis from pressure overload by blocking TGF-ß1 signaling. Sprague-Dawley rats underwent transverse aortic constriction (TAC) or a sham operation. After one month, rats received either sVAP32 (15mg/kg/day) or vehicle for an additional one month. TAC surgery induced significant cardiac dysfunction, fibroblast activation and fibrosis; these effects were improved by treatment with sVAP32. In the heart tissue, TAC remarkably increased the expression of TGF-ß1 and connective tissue growth factor (CTGF), reactive oxygen species levels, and the phosphorylation levels of Smad2/3 and extracellular signal-regulated kinases 1/2 (ERK1/2). SVAP32 inhibited the increases in reactive oxygen species levels, CTGF expression and the phosphorylation of Smad2/3 and ERK1/2, but not TGF-ß1 expression. In cultured cardiac fibroblasts, angiotensin II (Ang II) had similar effects compared to TAC surgery, such as increases in α-SMA-positive cardiac fibroblasts and collagen synthesis. SVAP32 eliminated these effects by disrupting TGF-ß1 binding to its receptors and blocking Ang II/TGF-ß1 downstream signaling. These results demonstrated that sVAP32 has anti-fibrotic effects by blocking the TGF-ß1 pathway in cardiac fibroblasts.

EPA, not DHA, prevents fibrosis in pressure overload-induced heart failure: potential role of free fatty acid receptor 4.

Heart failure with preserved ejection fraction (HFpEF) is half of all HF, but standard HF therapies are ineffective. Diastolic dysfunction, often secondary to interstitial fibrosis, is common in HFpEF. Previously, we found that supra-physiologic levels of ω3-PUFAs produced by 12 weeks of ω3-dietary supplementation prevented fibrosis and contractile dysfunction following pressure overload [transverse aortic constriction (TAC)], a model that resembles aspects of remodeling in HFpEF. This raised several questions regarding ω3-concentration-dependent cardioprotection, the specific role of EPA and DHA, and the relationship between prevention of fibrosis and contractile dysfunction. To achieve more clinically relevant ω3-levels and test individual ω3-PUFAs, we shortened the ω3-diet regimen and used EPA- and DHA-specific diets to examine remodeling following TAC. The shorter diet regimen produced ω3-PUFA levels closer to Western clinics. Further, EPA, but not DHA, prevented fibrosis following TAC. However, neither ω3-PUFA prevented contractile dysfunction, perhaps due to reduced uptake of ω3-PUFA. Interestingly, EPA did not accumulate in cardiac fibroblasts. However, FFA receptor 4, a G protein-coupled receptor for ω3-PUFAs, was sufficient and required to block transforming growth factor ß1-fibrotic signaling in cultured cardiac fibroblasts, suggesting a novel mechanism for EPA. In summary, EPA-mediated prevention of fibrosis could represent a novel therapy for HFpEF.

Berberine improves pressure overload-induced cardiac hypertrophy and dysfunction through enhanced autophagy.

Cardiac hypertrophy is a maladaptive change in response to pressure overload, and is also an important risk for developing heart failure. Berberine is known to have cardioprotective effects in patients with hypertension and in animal models of cardiac hypertrophy. In the current study, we observed that transverse aortic contraction (TAC) surgery induced a marked increase in heart size, the ratio of heart weight to body weight, cardiomyocyte apoptosis, myocardial fibrosis, and hypertrophic marker brain natriuretic peptide, all of which were effectively suppressed by berberine administration. In addition, berberine enhanced autophagy in hypertrophic hearts, which was accompanied by a decrease in heart size, cardiac apoptosis, and the attenuation of cardiac dysfunction. Furthermore, use of autophagy inhibitor 3-methyladenine (3-MA) blocked berberine-induced autophagy level, and abrogated the protection of berberine against heart hypertrophy, cardiac dysfunction, and apoptosis. Berberine ameliorated TAC-induced endoplasmic reticulum stress, which was also abolished by 3-MA. Moreover, berberine significantly inhibited the upstream signaling of autophagy, such as the mammalian target of rapamycin (mTOR), extracellular signal-regulated kinase (ERK1/2), and p38 mitogen-activated protein kinase (MAPK) phosphorylation. We conclude that berberine could attenuate left ventricular remodeling and cardiomyocyte apoptosis through an autophagy-dependent mechanism in a rat model of cardiac hypertrophy, which is, at least in part, associated with enhanced autophagy through inhibition of mTOR, p38 and ERK1/2 MAPK signaling pathways.