Modified citrus pectin prevents isoproterenol-induced cardiac hypertrophy associated with p38 signalling and TLR4/JAK/STAT3 pathway.

Modified citrus pectin (MCP) is a specific inhibitor of galectin-3 (Gal-3) that is regarded as a new biomarker of cardiac hypertrophy, but its effect is unclear. The aim of this study is to investigate the role and mechanism of MCP in isoproterenol (ISO)-induced cardiac hypertrophy. Rats were injected with ISO to induce cardiac hypertrophy and treated with MCP. Cardiac function was detected by ECG and echocardiography. Pathomorphological changes were evaluated by the haematoxylin eosin (H&E) and wheat germ agglutinin (WGA) staining. The hypertrophy-related genes for atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), and ß-myosin heavy chain (ß-MHC), and the associated signal molecules were analysed by qRT-PCR and western blotting. The results show that MCP prevented cardiac hypertrophy and ameliorated cardiac dysfunction and structural disorder. MCP also decreased the levels of ANP, BNP, and ß-MHC and inhibited the expression of Gal-3 and Toll-like receptor 4 (TLR4). Additionally, MCP blocked the phosphorylation of Janus kinase 2 (JAK2) and signal transducer and activator of transcription 3 (STAT3), but it promoted the phosphorylation of p38. Thus, MCP prevented ISO-induced cardiac hypertrophy by activating p38 signalling and inhibiting the Gal-3/TLR4/JAK2/STAT3 pathway.

Xinyang Tablet inhibits MLK3-mediated pyroptosis to attenuate inflammation and cardiac dysfunction in pressure overload.

ETHNOPHARMACOLOGICAL RELEVANCE: Xinyang tablet (XYT) has been traditionally used in the treatment of cardiovascular diseases (CVDs). Our previous study indicated that XYT exhibited protective effects in heart failure (HF). AIM OF THE STUDY: The aim of the present study was to determine the protective effects of XYT in pressure overload induced HF and to elucidate its underlying mechanisms of action. MATERIALS AND METHODS: We analyzed XYT content using high-performance liquid chromatography (HPLC.). Mice were subjected to transverse aortic constriction (TAC) to generate pressure overload-induced cardiac remodeling and were then orally administered XYT or URMC-099 for 1 week after the operation. HL1 mouse cardiomyoblasts were induced by lipopolysaccharides (LPS) to trigger pyroptosis and were then treated with XYT or URMC-099. We used echocardiography (ECG), hematoxylin and eosin (H&E) staining, Masson's trichrome staining and a terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) assay to evaluate the effects of XYT. Messenger ribonucleic acid (mRNA) levels of collagen metabolism biomarkers and inflammation-related factors were detected. We determined protein levels of inflammation- and pyroptosis-related signaling pathway members via Western blot (WB). Caspase-1 activity was measured in cell lysate using a Caspase-1 Activity Assay Kit. Subsequently, to define the candidate ingredients in XYT that regulate mixed-lineage kinase-3 (MLK3), we used molecular docking (MD) to predict and evaluate binding affinity with MLK3. Finally, we screened 24 active potential compounds that regulate MLK3 via MD. RESULTS: ECG, H&E staining, Masson's trichrome staining and TUNEL assay results showed that XYT remarkably improved heart function, amelorated myocardial fibrosis and inhibited apoptosis in vivo. Moreover, it reduced expression of proteins or mRNAs related to collagen metabolism, including collagen type 1 (COL1), fibronectin (FN), alpha smooth-muscle actin (α-SMA), and matrix metalloproteinases-2 and -9 (MMP-2, MMP-9). XYT also inhibited inflammation and the induction of pyroptosis at an early stage, as well as attenuated inflammation and pyroptosis levels in vitro. CONCLUSION: Our data indicated that XYT exerted protective effects against pressure overload induced myocardial fibrosis (MF), which might be associated with the induction of pyroptosis-mediated MLK3 signaling.

Allyl Methyl Sulfide Preserved Pressure Overload-Induced Heart Failure Via Modulation of Mitochondrial Function.

BACKGROUND: Cardiovascular diseases are the leading cause of death globally, and they are causing enormous socio-economic burden to the developed and developing countries. Allyl Methyl Sulfide (AMS) is a novel cardioprotective metabolite identified in the serum of rats after raw garlic administration. The present study explored the cardioprotective effect of AMS on thoracic aortic constriction (TAC)-induced cardiac hypertrophy and heart failure model in rats. METHODS: Thoracic aortic constriction (TAC) by titanium ligating clips resulted in the development of pressure overload-induced cardiac hypertrophy and heart failure model. Four weeks prior to TAC and for 8 weeks after TAC, Sprague Dawley (SD) rats were administered with AMS (25 and 50 mg/kg/day) or Enalapril (10 mg/kg/day). RESULTS: We have observed AMS (25 and 50 mg/kg/day) intervention significantly improved structural and functional parameters of the heart. mRNA expression of fetal genes i.e., atrial natriuretic peptide (ANP), alpha skeletal actin (α-SA) and beta myosin heavy chain (ß-MHC) were reduced in AMS treated TAC hearts along with decrease in perivascular and interstitial fibrosis. AMS attenuated lipid peroxidation and improved protein expression of endogenous antioxidant enzymes i.e., catalase and manganese superoxide dismutase (MnSOD) along with electron transport chain (ETC) complex activity. AMS increased mitochondrial fusion proteins i.e., mitofusin 1 (MFN1), mitofusin 2 (MFN2) and optic atrophy protein (OPA1), and reduced fission protein i.e., dynamin-related protein 1 (DRP1). Preliminary study suggests that AMS intervention upregulated genes involved in mitochondrial bioenergetics in normal rats. Further, in-vitro studies suggest that AMS reduced mitochondrial reactive oxygen species (ROS), preserved mitochondrial membrane potential and oxygen consumption rate (OCR) in isoproterenol-treated cardiomyoblast. CONCLUSION: This study demonstrated that AMS protected cardiac remodelling, LV dysfunction and fibrosis in pressure overload-induced cardiac hypertrophy and heart failure model by improving endogenous antioxidants and mitochondrial function.

Echinacoside reverses myocardial remodeling and improves heart function via regulating SIRT1/FOXO3a/MnSOD axis in HF rats induced by isoproterenol.

Myocardial remodelling is important pathological basis of HF, mitochondrial oxidative stress is a promoter to myocardial hypertrophy, fibrosis and apoptosis. ECH is the major active component of a traditional Chinese medicine Cistanches Herba, plenty of studies indicate it possesses a strong antioxidant capacity in nerve cells and tumour, it inhibits mitochondrial oxidative stress, protects mitochondrial function, but the specific mechanism is unclear. SIRT1/FOXO3a/MnSOD is an important antioxidant axis, study finds that ECH binds covalently to SIRT1 as a ligand and up-regulates the expression of SIRT1 in brain cells. We hypothesizes that ECH may reverse myocardial remodelling and improve heart function of HF via regulating SIRT1/FOXO3a/MnSOD signalling axis and inhibit mitochondrial oxidative stress in cardiomyocytes. Here, we firstly induce cellular model of oxidative stress by ISO with AC-16 cells and pre-treat with ECH, the level of mitochondrial ROS, mtDNA oxidative injury, MMP, carbonylated protein, lipid peroxidation, intracellular ROS and apoptosis are detected, confirm the effect of ECH in mitochondrial oxidative stress and function in vitro. Then, we establish a HF rat model induced by ISO and pre-treat with ECH. Indexes of heart function, myocardial remodelling, mitochondrial oxidative stress and function, expression of SIRT1/FOXO3a/MnSOD signalling axis are measured, the data indicate that ECH improves heart function, inhibits myocardial hypertrophy, fibrosis and apoptosis, increases the expression of SIRT1/FOXO3a/MnSOD signalling axis, reduces the mitochondrial oxidative damages, protects mitochondrial function. We conclude that ECH reverses myocardial remodelling and improves cardiac function via up-regulating SIRT1/FOXO3a/MnSOD axis and inhibiting mitochondrial oxidative stress in HF rats.

Combination of Dichloroacetate and Atorvastatin Regulates Excessive Proliferation and Oxidative Stress in Pulmonary Arterial Hypertension Development via p38 Signaling.

Pulmonary arterial hypertension (PAH) is a lethal disease generally characterized by pulmonary artery remodeling. Mitochondrial metabolic disorders have been implicated as a critical regulator of excessively proliferative- and apoptosis-resistant phenotypes in pulmonary artery smooth muscle cells (PASMCs). Dichloroacetate (DCA) is an emerging drug that targets aerobic glycolysis in tumor cells. Atorvastatin (ATO) is widely used for hyperlipemia in various cardiovascular diseases. Considering that DCA and ATO regulate glucose and lipid metabolism, respectively, we hypothesized that the combination of DCA and ATO could be a potential treatment for PAH. A notable decrease in the right ventricular systolic pressure accompanied by reduced right heart hypertrophy was observed in the DCA/ATO combination treatment group compared with the monocrotaline treatment group. The DCA/ATO combination treatment alleviated vascular remodeling, thereby suppressing excessive PASMC proliferation and macrophage infiltration. In vitro, both DCA and ATO alone reduced PASMC viability by upregulating oxidative stress and lowering mitochondrial membrane potential. Surprisingly, when combined, DCA/ATO was able to decrease the levels of reactive oxygen species and cell apoptosis without compromising PASMC proliferation. Furthermore, suppression of the p38 pathway through the specific inhibitor SB203580 attenuated cell death and oxidative stress at a level consistent with that of DCA/ATO combination treatment. These observations suggested a complementary effect of DCA and ATO on rescuing PASMCs from a PAH phenotype through p38 activation via the regulation of mitochondrial-related cell death and oxidative stress. DCA in combination with ATO may represent a novel therapeutic strategy for PAH treatment.

Qingda granules attenuate hypertensive cardiac remodeling and inflammation in spontaneously hypertensive rats.

Qingda granules (QDG) are derived from QingXuanJiangYa Decoction (QXJYD) a traditional Chinese medication that has been used to treat hypertension for more than 60 years. QXJYD has been shown to be effective in rat models of hypertension. However, the effects of QDG on hypertension remain largely unknown. In the current study, baicalin was identified as one of the main components of QDG using Ultra Performance Liquid Chromatography (UPLC) analysis. We investigated the effects of QDG on blood pressure, cardiac remodeling, and cardiac inflammation. QDG (0.8 g/kg/day) treatment attenuated the elevated blood pressure in spontaneously hypertensive rats (SHRs). Moreover, QDG treatment reduced the degree of myocardial fiber disarray, degeneration and necrosis of myocardial cells, expression of ANP and BNP, as well as collagen content of SHRs. Moreover, we further assessed the effect of QDG treatment on cardiac inflammation and found that QDG treatment reduced CD68 protein expression, decreased levels of IL-6 and TNF-α in both serum and cardiac tissues, as well as suppressed activation of NF-κB pathway in cardiac tissues of SHRs. Differential expressed metabolites (DEMs) analysis identified 41 increased and 51 decreased metabolites in the cardiac tissues of SHRs after QDG treatment. In summary, QDG treatment of SHRs attenuated the elevated blood pressure and ameliorated cardiac remodeling and inflammation, in part, through suppression of NF-κB pathway and DEMs, which provide a basis for other therapeutic uses of this TCM.

Danhong Injection Alleviates Cardiac Fibrosis via Preventing the Hypermethylation of Rasal1 and Rassf1 in TAC Mice.

BACKGROUND/AIM: Danhong injection (DHI) is a Chinese patent drug used for relieving cardiovascular diseases. Recent studies have suggested that DNA methylation plays a pivotal role in the maintenance of cardiac fibrosis (CF) in cardiovascular diseases. This study was aimed at identifying the effect and the underlying mechanism of DHI on CF, especially the DNA methylation. METHODS: A CF murine model was established by thoracic aortic constriction (TAC). A 28-day daily treatment with or without DHI via intraperitoneal injection was carried out immediately following TAC surgery. The changes in cardiac function, pathology, and fibrosis following TAC were measured by echocardiography and immunostaining. We used methyl-seq analysis to assess the DNA methylation changes in whole genes and identified the methylation changes of two Ras signaling-related genes in TAC mice, including Ras protein activator like-1 (Rasal1) and Ras-association domain family 1 (Rassf1). Next, the methylation status and expression levels of Rasal1 and Rassf1 genes were consolidated by bisulfite sequencing, quantitative reverse transcription polymerase chain reaction (RT-qPCR), and Western blotting, respectively. To determine the underlying molecular mechanism, the expressions of DNA methyltransferases (DNMTs), Tet methylcytosine dioxygenase 3 (TET3), fibrosis-related genes, and the activity of Ras/ERK were measured by RT-qPCR and Western blotting. RESULTS: DHI treatment alleviated CF and significantly improved cardiac function on day 28 of TAC. The methyl-seq analysis identified 42,606 differential methylated sites (DMSs), including 19,618 hypermethylated DMSs and 22,988 hypomethylated DMSs between TAC and sham-operated mice. The enrichment analysis of these DMSs suggested that the methylated regulation of Ras signal transduction and focal adhesion-related genes would be involved in the TAC-induced CF development. The results of bisulfite sequencing revealed that the TAC-induced methylation affected the CpG site in both of Rasal1 and Rassf1 genes, and DHI treatment remarkably downregulated the promoter methylation of Rasal1 and Rassf1 in CF hearts. Furthermore, DHI treatment upregulated the expressions of Rasal1 and Rassf1, inhibited the hyperactivity of Ras/ERK, and decreased the expressions of fibrosis-related genes. Notably, we found that DHI treatment markedly downregulated the expression of DNMT3B in CF hearts, while it did not affect the expressions of DNMT1, DNMT3A, and TET3. CONCLUSION: Aberrant DNA methylation of Rasal1 and Rassf1 genes was involved in the CF development. DHI treatment alleviated CF, prevented the hypermethylation of Rasal1 and Rassf1, and downregulated DNMT3B expression in CF hearts.

Myocardial hypertrophy is improved with berberine treatment via long non-coding RNA MIAT-mediated autophagy.

OBJECTIVES: This study aimed to evaluate berberine (BBR) effects on myocardial hypertrophy (MH) and associated mechanisms. METHODS: BBR effects on MH were evaluated in rats with constriction of abdominal aorta (CAA). qRT-PCR assay was used to measure MH-related genes, long non-coding RNAs (lncRNAs) and autophagy-related genes expressions. Western blot was performed to detect autophagy markers expression. Filamentous actin and phalloidin expressions were detected using immunofluorescence assay. KEY FINDINGS: BBR significantly attenuated CAA-induced MH and cardiomyocyte enlargement. CAA upregulated ß myosin heavy chain and atrial natriuretic peptide expressions in heart tissues, which was attenuated by BBR. BBR suppressed myocardial infarction associated transcript (MIAT) expression in rats with CAA. p62 mRNA expression was upregulated and beclin1 and autophagy related 5 were downregulated in CAA versus control groups. The effects were abolished by BBR. In vitro studies showed that BBR ameliorated angiotensin II-induced MH and attenuated Ang II-induced MIAT expression in H9C2 cells. Expressions of phosphorylated mTOR, phosphorylated AMPK and LC3 were upregulated in H9C2 cells after Ang II stimulation, and the effects were abolished by BBR. CONCLUSIONS: BBR exerted beneficial effects on MH induced by CCA, and the mechanisms were associated with decreased MIAT expression and enhanced autophagy.

Xiao-Qing-Long Tang Prevents Cardiomyocyte Hypertrophy, Fibrosis, and the Development of Heart Failure with Preserved Ejection Faction in Rats by Modulating the Composition of the Gut Microbiota.

BACKGROUND: Changes in the gut microbiota are associated with cardiovascular disease progression. Xiao-Qing-Long Tang (XQLT), a traditional herbal formula, has an anti-inflammatory effect and regulates the steady state of the immune system, which is also associated with the progression of heart failure with preserved ejection faction (HFpEF). In this study, we investigated whether XQLT could contribute to prevent the development of HFpEF and whether the modulation of the gut microbiota by this herbal formula could be involved in such effect. METHODS: The gut microbiota, SCFAs, the histology/function of the heart, and systolic blood pressure were examined to evaluate the effect of XQLT on the gut microbiota and the progression of HFpEF after oral administration of XQLT to model rats. Furthermore, we evaluated, through fecal microbiota transplantation experiments, whether the favorable effects of XQLT could be mediated by the gut microbiota. RESULTS: Oral administration of XQLT contributed to the reduction of elevated blood pressure, inflammation, and compensatory hypertrophy, features that are associated with the progression of HFpEF. The gut microbiota composition, SCFA levels, and intestinal mucosal histology were improved after treatment with XQLT. Moreover, fecal transfer from XQLT-treated rats was sufficient to prevent the progression of HFpEF. CONCLUSIONS: These data suggested that XQLT prevented the development of HFpEF in model rats by regulating the composition of the gut microbiota.

Cordycepin ameliorates cardiac hypertrophy via activating the AMPKα pathway.

Increase of myocardial oxidative stress is closely related to the occurrence and development of cardiac hypertrophy. Cordycepin, also known as 3'-deoxyadenosine, is a natural bioactive substance extracted from Cordyceps militaris (which is widely cultivated for commercial use in functional foods and medicine). Since cordycepin suppresses oxidative stress both in vitro and in vivo, we hypothesized that cordycepin would inhibit cardiac hypertrophy by blocking oxidative stress-dependent related signalling. In our study, a mouse model of cardiac hypertrophy was induced by aortic banding (AB) surgery. Mice were intraperitoneally injected with cordycepin (20 mg/kg/d) or the same volume of vehicle 3 days after-surgery for 4 weeks. Our data demonstrated that cordycepin prevented cardiac hypertrophy induced by AB, as assessed by haemodynamic parameters analysis and echocardiographic, histological and molecular analyses. Oxidative stress was estimated by detecting superoxide generation, superoxide dismutase (SOD) activity and malondialdehyde levels, and by detecting the protein levels of gp91phox and SOD. Mechanistically, we found that cordycepin activated activated protein kinase α (AMPKα) signalling and attenuated oxidative stress both in vivo in cordycepin-treated mice and in vitro in cordycepin treated cardiomyocytes. Taken together, the results suggest that cordycepin protects against post-AB cardiac hypertrophy through activation of the AMPKα pathway, which subsequently attenuates oxidative stress.

Ginseng Berry Extract Rich in Phenolic Compounds Attenuates Oxidative Stress but not Cardiac Remodeling post Myocardial Infarction.

The cardioprotective effects of ginseng root extracts have been reported. However, nothing is known about the myocardial actions of the phenolic compounds enriched in ginseng berry. Therefore, this study was undertaken to investigate the effects of American ginseng berry extract (GBE) in an experimental model of myocardial infarction (MI). Coronary artery ligation was performed on Sprague⁻Dawley male rats to induce MI after which animals were randomized into groups receiving either distilled water or GBE intragastrically for 8 weeks. Echocardiography and assays for malondialdehyde (MDA) and TNF-α were conducted. Flow cytometry was used to test the effects of GBE on T cell phenotypes and cytokine production. Although GBE did not improve the cardiac functional parameters, it significantly attenuated oxidative stress in post-MI rat hearts. GBE treatment also resulted in lower than control levels of TNF-α in post-MI rat hearts indicating a strong neutralizing effect of GBE on this cytokine. However, there was no effect of GBE on the proportion of different T cell subsets or ex-vivo cytokine production. Taken together, the present study demonstrates GBE reduces oxidative stress, however no effect on cardiac structure and function in post-MI rats. Moreover, reduction of TNF-α levels below baseline raises concern regarding its use as prophylactic or preventive adjunct therapy in cardiovascular disease.

MG53, A Novel Regulator of KChIP2 and Ito,f, Plays a Critical Role in Electrophysiological Remodeling in Cardiac Hypertrophy.

BACKGROUND: KChIP2 (K+ channel interacting protein) is the auxiliary subunit of the fast transient outward K+ current ( Ito,f) in the heart, and insufficient KChIP2 expression induces Ito,f downregulation and arrhythmogenesis in cardiac hypertrophy. Studies have shown muscle-specific mitsugumin 53 (MG53) has promiscuity of function in the context of normal and diseased heart. This study investigates the possible roles of cardiac MG53 in regulation of KChIP2 expression and Ito,f, and the arrhythmogenic potential in hypertrophy. METHODS: MG53 expression is manipulated by genetic ablation of MG53 in mice and adenoviral overexpression or knockdown of MG53 by RNA interference in cultured neonatal rat ventricular myocytes. Cardiomyocyte hypertrophy is produced by phenylephrine stimulation in neonatal rat ventricular myocytes, and pressure overload-induced mouse cardiac hypertrophy is produced by transverse aortic constriction. RESULTS: KChIP2 expression and Ito,f density are downregulated in hearts from MG53-knockout mice and MG53-knockdown neonatal rat ventricular myocytes, but upregulated in MG53-overexpressing cells. In phenylephrine-induced cardiomyocyte hypertrophy, MG53 expression is reduced with concomitant downregulation of KChIP2 and Ito,f, which can be reversed by MG53 overexpression, but exaggerated by MG53 knockdown. MG53 knockout enhances Ito,f remodeling and action potential duration prolongation and increases susceptibility to ventricular arrhythmia in mouse cardiac hypertrophy. Mechanistically, MG53 regulates NF-κB (nuclear factor kappa-light-chain-enhancer of activated B cells) activity and subsequently controls KChIP2 transcription. Chromatin immunoprecipitation demonstrates NF-κB protein has interaction with KChIP2 gene. MG53 overexpression decreases, whereas MG53 knockdown increases NF-κB enrichment at the 5' regulatory region of KChIP2 gene. Normalizing NF-κB activity reverses the alterations in KChIP2 in MG53-overexpressing or knockdown cells. Coimmunoprecipitation and Western blotting assays demonstrate MG53 has physical interaction with TAK1 (transforming growth factor-b [TGFb]-activated kinase 1) and IκBα (nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor, alpha), critical components of the NF-κB pathway. CONCLUSIONS: These findings establish MG53 as a novel regulator of KChIP2 and Ito,f by modulating NF-κB activity and reveal its critical role in electrophysiological remodeling in cardiac hypertrophy.

Diabetic cardiomyopathy: molecular mechanisms, detrimental effects of conventional treatment, and beneficial effects of natural therapy.

ABSTARCT: Diabetic complications are among the largely exigent health problems currently. Cardiovascular complications, including diabetic cardiomyopathy (DCM), account for more than 80% of diabetic deaths. Investigators are exploring new therapeutic targets to slow or abate diabetes because of the growing occurrence and augmented risk of deaths due to its complications. Research on rodent models of type 1 and type 2 diabetes mellitus, and the use of genetic engineering techniques in mice and rats have significantly sophisticated for our understanding of the molecular mechanisms in human DCM. DCM is featured by pathophysiological mechanisms that are hyperglycemia, insulin resistance, oxidative stress, left ventricular hypertrophy, damaged left ventricular systolic and diastolic functions, myocardial fibrosis, endothelial dysfunction, myocyte cell death, autophagy, and endoplasmic reticulum stress. A number of molecular and cellular pathways, such as cardiac ubiquitin proteasome system, FoxO transcription factors, hexosamine biosynthetic pathway, polyol pathway, protein kinase C signaling, NF-κB signaling, peroxisome proliferator-activated receptor signaling, Nrf2 pathway, mitogen-activated protein kinase pathway, and micro RNAs, play a major role in DCM. Currently, there are a few drugs for the management of DCM and some of them have considerable adverse effects. So, researchers are focusing on the natural products to ameliorate it. Hence, in this review, we discuss the pathogical, molecular, and cellular mechanisms of DCM; the current diagnostic methods and treatments; adverse effects of conventional treatment; and beneficial effects of natural product-based therapeutics, which may pave the way to new treatment strategies. Graphical Abstract.

Effects of electroacupuncture at Taichong (LR 3) and Baihui (DU 20) on cardiac hypertrophy in rats with spontaneous hypertension.

OBJECTIVE: To investigate the effects of electroacupuncture (EA) at Taichong (LR 3) and Baihui (DU 20) on myocardial hypertrophy in spontaneously hypertensive rats (SHRs). METHODS: Thirty-six SHRs were randomly assigned to model, EA, and Losartan groups, with twelve rats per group. Twelve Wistar Kyoto rats were selected as the normal control group. Systolic blood pressure (SBP) and cardiac function were measured in all rats. Expression levels of factors associated with the phosphoinositide 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/Akt/mTOR) pathway were evaluated by Western blotting and real-time PCR. Pathological changes of the heart tissue were observed by hematoxylin-eosin staining. RESULTS: After treatment, enhanced SBP was significantly decreased in the EA and Losartan groups compared with the model group (P < 0.01). Echocardiographic and morphological analyses revealed that enhanced end-diastolic interventricular septal thickness and left ventricular posterior wall thickness, as well as ratio of left ventricular weight to body weight were markedly diminished in the EA and Losartan groups (P < 0.01 or P < 0.05), while reduced left ventricular end-diastolic dimension and left ventricular ejection fraction were significantly ameliorated (P < 0.01). Real-time PCR and western blotting analyses showed that the expression levels of PI3K, Akt, and mTOR in SHRs were significantly up-regulated by EA and Losartan (P < 0.01), while the expression levels of PTEN and ANP were down-regulated (P < 0.01). CONCLUSION: EA at Taichong (LR 3) and Baihui (DU 20) inhibited the development of cardiac hypertrophy and improved the cardiac function in SHRs, possibly through regulation of the PI3K/Akt/mTOR signalling pathway.

Maslinic acid protects against pressure overload-induced cardiac hypertrophy in mice.

Cardiac hypertrophy is characterized by myocyte hypertrophy, accumulation of cardiac collagen, and reactivation of fetal genes. Maslinic acid (MA) is a pentacyclic triterpene with abundance in olive fruit skin and possesses a number of pharmacological actions. However, its effect on pressure overload-induced cardiac hypertrophy remains unknown. Here, we were to investigate the protective effect of MA on cardiac hypertrophy and fibrosis. C57 mice were subjected to aortic banding (AB) or sham surgery. One day after surgery, all the mice were orally given MA (20 mg/kg) or vehicle for the following four weeks. MA could protect against pressure overload-induced cardiac hypertrophy and cardiac fibrosis, as indicated by decreased heart weight/tibia length, and cardiomyocytes cell area and hypertrophic and fibrotic markers. MA treatment also improved cardiac function in mice with AB surgery, as assessed by echocardiographic and hemodynamic analysis. MA reduced phosphorylation of protein kinase B and extracellular regulated protein kinases in the hypertrophic hearts. MA could decrease cardiomyocyte hypertrophy, and inhibit the activation of AKT and ERK signaling pathway in vitro. In conclusion, we found that MA protected against cardiac hypertrophy. MA has the potential to become a therapeutic drug for cardiac hypertrophy.

Effect of Calcium on Slow Force Responses in Isolated Right Ventricle Preparations of Healthy and Hypertrophied Myocardium in Male and Female Rats.

Effect of different Ca2+ concentrations in the bathing solution [Ca2+]o on the parameters of single isometric contraction and slow force response to stretching was studied in isolated preparations of healthy and hypertrophied myocardium of male and female Wistar rats. In all groups of experimental animals, the increase in calcium concentration was followed by a decrease in the myocardium slow response intensity. We revealed a complementary relationship between the current and medium-term systems of myocardial contractility regulation by the length of the myocardium aimed at the maintenance of the constant level during adaptation to the load. Slow responses of the hypertrophied rat heart myocardium were suppressed in comparison with those in the healthy myocardium and their intensity did not depend on animal sex.

Eriobotrya japonica ameliorates cardiac hypertrophy in H9c2 cardiomyoblast and in spontaneously hypertensive rats.

Eriobotrya japonica (EJ) is a traditional Chinese plant with high medicinal value. EJ extracts are reported to exhibit antioxidant and anti-inflammatory biological attributes. The current study aims to evaluate the prospective efficacy of E. japonica leave extract (EJLE) against Angiotensin-II induced cardiac hypertrophy in H9c2 cardiomyoblast and in spontaneously hypertensive rats (SHRs). For the in vitro studies, Angiotensin-II pretreated H9c2 cells were treated with EJLE and analyzed through Western blotting and rhodamine phalloidin staining for their cardio-protective attributes. In the in vivo studies, 12-week-old SHRs were randomly divided into groups: SHRs supplemented with EJLE, control SHR group supplemented with PBS; in addition, a control group of Wistar-Kyoto rats (WKY) was also employed. All rats were supplemented twice a week for 8 week time interval. Finally, echocardiography, morphological, histology, and Western blot analysis were performed to assess their role against cardiac hypertrophy. Interestingly, we could observe that supplementation of EJLE could rescue Ang-II induced cardiac hypertrophy as evident through Western blot, rhodamine phalloidin staining, and Hematoxylin-Eosin staining. Notably, morphological and echocardiography data provided further supports for their ability to ameliorate cardiac characteristics. Cumulatively, the results clearly suggests that supplementation of EJLE promotes cardio-protective effects through amelioration of cardiac hypertrophy in vitro and in vivo.

Glucose is preferentially utilized for biomass synthesis in pressure-overloaded hearts: evidence from fatty acid-binding protein-4 and -5 knockout mice.

Aims: The metabolism of the failing heart is characterized by an increase in glucose uptake with reduced fatty acid (FA) oxidation. We previously found that the genetic deletion of FA-binding protein-4 and -5 [double knockout (DKO)] induces an increased myocardial reliance on glucose with decreased FA uptake in mice. However, whether this fuel switch confers functional benefit during the hypertrophic response remains open to debate. To address this question, we investigated the contractile function and metabolic profile of DKO hearts subjected to pressure overload. Methods and results: Transverse aortic constriction (TAC) significantly reduced cardiac contraction in DKO mice (DKO-TAC), although an increase in cardiac mass and interstitial fibrosis was comparable with wild-type TAC (WT-TAC). DKO-TAC hearts exhibited enhanced glucose uptake by 8-fold compared with WT-TAC. Metabolic profiling and isotopomer analysis revealed that the pool size in the TCA cycle and the level of phosphocreatine were significantly reduced in DKO-TAC hearts, despite a marked increase in glycolytic flux. The ingestion of a diet enriched in medium-chain FAs restored cardiac contractile dysfunction in DKO-TAC hearts. The de novo synthesis of amino acids as well as FA from glycolytic flux was unlikely to be suppressed, despite a reduction in each precursor. The pentose phosphate pathway was also facilitated, which led to the increased production of a coenzyme for lipogenesis and a precursor for nucleotide synthesis. These findings suggest that reduced FA utilization is not sufficiently compensated by a robust increase in glucose uptake when the energy demand is elevated. Glucose utilization for sustained biomass synthesis further enhances diminishment of the pool size in the TCA cycle. Conclusions: Our data suggest that glucose is preferentially utilized for biomass synthesis rather than ATP production during pressure-overload-induced cardiac hypertrophy and that the efficient supplementation of energy substrates may restore cardiac dysfunction caused by energy insufficiency.

Rosuvastatin improves myocardial hypertrophy after hemodynamic pressure overload via regulating the crosstalk of Nrf2/ARE and TGF-ß/ smads pathways in rat heart.

Left ventricular hypertrophy is more commonly associated with hemodynamic overload imposed by hypertension or volume overload. Transforming growth factor ß (TGF-ß) is involved in the cardiac hypertrophy and fibrosis of the left ventricle. The fact that TGF-ß1 and the nuclear factor erythroid 2-related factor 2 (Nrf2) both become up-regulated upon persistent vessel overload suggests that these two factors may virtually impact on their signaling pathways. In this research, 40 rats were divided into sham group, model group, rosuvastatin low and high dose group. Rat models were established by incomplete constriction of abdominal aorta. After five weeks treatment, blood pressure, heart mass index (HMI), hemodynamic parameters and the average diameter of myocardium cell and collagen volume fraction (CVF) improved significantly in rosuvastatin groups, compared with the model group. Both rosuvastatin groups, increased in expression of Smad7, Nrf2, NAD (P) H dehydrogenase [quinone] 1 (Nqo1) and heme oxygenase 1(Ho1),and decreased in expression of TGF-ßl、Smad3 compared with the model group. Results from co-immunoprecipitation and GST pull down showed that Nrf2 interacts with Smad7. Our results revealed the crosstalk between TGF-ß1/Smads and Nrf2/ antioxidant response elements (ARE) pathways in myocardial remodeling through the interaction between Smad7 and Nrf2. Rosuvastatin can improve cardiac function and hypertrophy by regulating the crosstalk of the two signaling pathways.

A20 prevents obesity-induced development of cardiac dysfunction.

Obesity and an increased free fatty acid (FFA) level are tightly linked, leading to aberrant oxidative stress, inflammation, apoptosis, and progression to cardiovascular disorders. A20 is a ubiquitin-modifying enzyme that plays a significant role in the negative regulation of inflammatory response. Here, we study the role of A20 in obesity-induced heart injury and explore the underlying mechanisms. A20 expression was first increased in mouse hearts after 4 weeks of a high-fat diet (HFD) and then was gradually decreased in the following 20 weeks. Cardiac-specific supplementation with A20 via recombinant adeno-associated virus subtype 9 (rAAV9) could reverse myocardial dysfunction, hypertrophy and fibrosis in mice exposed to 24 weeks of HFD, along with reduced cardiac apoptosis and inflammation. The beneficial actions of A20 were closely associated with its ability to repress TAK1 activation and the downstream inhibition of P38, JNK1/2, and the NF-κB pathway. TAK1 over-expression could efficiently retard the above-mentioned positive effects of A20. Therefore, our data uncovered a novel function of A20 in obesity-induced heart injury and presented a therapeutic approach for the treatment of obesity-related cardiovascular disorders. KEY MESSAGES: A20 expression is downregulated in obesity-related hearts. A20 ameliorates HFD-induced lipid accumulation, ROS, inflammation, apoptosis, hypertrophy, fibrosis, and cardiac dysfunction. A20 represses TAK1 activation and the downstream inhibition of P38, JNK1/2, and the NF-κB pathway. TAK1 overexpression retards the beneficial effects of A20.