Identification of Atrial Fibrillation-Related lncRNA Based on Bioinformatic Analysis.

BACKGROUND: Atrial fibrillation (AF) is the most common arrhythmia in the world. Long noncoding RNA (lncRNA) has been found to play an important role in cardiovascular diseases including heart failure, myocardial infarction, and atherosclerosis. However, the role of lncRNA in AF has rarely been studied. The purpose of this study is to identify the expression profile of lncRNA in AF patients, explore the function of lncRNA in AF, and provide a potential scientific basis for the treatment of AF in the future. METHODS: The lncRNA and mRNA expression profiles were obtained from the atrial appendage samples of GSE31821, GSE411774, GSE79768, and GSE115574 in the Gene Expression Omnibus (GEO) database. Functional analysis was performed via Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and Gene Set Variation Analysis (GSVA). The "CIBERSORT" R kit was used to analyze 22 immune cell infiltrates in AF and sinus rhythm (SR) patients. The "CORRPLOT" R package was used to analyze the immune correlation between lncRNA and immune cells. RESULTS: A total of 6 differentially expressed lncRNAs and 45 differentially expressed mRNAs were identified in the AF and SR groups. GO, KEGG, and GSVA results showed that abnormally expressed lncRNAs were involved in signaling pathways related to the atrium, including the Toll-like receptor signaling pathway and calcium signaling pathway. Immune cell infiltration analysis revealed that native B cells, follicular helper T cells, and resting dendritic cells may be involved in the AF process. In addition, LINC00844 was negatively correlated with resting dendritic cells. CONCLUSION: The expression profile of lncRNA in AF patients was different from that in normal controls. The physiological functions of these differentially expressed lncRNAs may be related to the pathogenesis of AF, which provide a scientific basis for the prognosis and treatment of patients with AF.

17ß-Estradiol alleviates cardiac aging induced by d-galactose by downregulating the methylation of autophagy-related genes.

Intrinsic cardiac aging increases cardiovascular mortality and morbidity in the elderly. Estrogen helps reduce the risk of cardiovascular disease in women, with 17ß-estradiol (17ß-E2) activating the autophagy pathway and inhibiting vascular aging, mainly through estrogen receptor alpha (ER α) to prevent atherosclerosis. Abnormal methylation of autophagy-related genes can impact autophagic regulation. We hypothesized that 17ß-E2, specifically 17ß-E2 α, downregulates the methylation of autophagy factors and delays cardiac aging. Here, we used d-galactose, 17ß-E2, and ER α receptor antagonist methyl-piperidino-pyrazole (MPP) to establish different aging models in mice divided into four groups, namely negative control, D.gal, D.gal + 17ß-E2, and D.gal + 17ß-E2 + MPP groups. Echocardiography showed that compared with the D.gal group group, the D.gal + 17ß-E2 showed substantially increased cardiac function. The level of cardiac aging markers in mice in the D.gal + 17ß-E2 group was lower than that in mice in the D.gal group. Beclin1, LC3, and Atg5 mRNA and protein expression levels in mice in the D.gal + 17ß-E2 group were significantly increased compared with those in the D.gal group. Additionally, Beclin1, LC3, and Atg5 methylation levels were significantly decreased in the D.gal + 17ß-E2 group. All the above values of the D.gal + 17ß-E2 + MPP group were between those of the D.gal and D.gal + 17ß-E2 groups. The expression of Dnmt1, Dnmt2, and Dnmt3A genes was the highest in the D.gal group. In summary, our results suggest that 17ß-E2, specifically 17ß-E2 α, promotes autophagy by downregulating the methylation of autophagy factors, thereby inhibiting galactose-induced cardiac aging in mice. 17ß-E2 may be a potential therapeutic target to mitigate the effects of cardiac aging.

ET-1 regulates the human umbilical vein endothelial cell cycle by adjusting the ERß/FOXN1 signaling pathway.

BACKGROUND: Atherosclerosis (AS) is a chronic and progressive disease primarily induced by inflammation of the arterial blood vessel wall. Investigating the function and molecular regulation mechanisms of ET-1, ERß, and FOXN1 in disease models will provide new targets and means for clinical treatment. METHODS: The effects of ET-1 on oxidative stress in HUVEC were verified through quantitative polymerase chain reaction (qPCR), western blot, flow cytometry, as well as dual luciferase reporter gene and biochemical assays. RESULTS: Compared with the ET-1+ negative control (NC) group, the ERß messenger ribonucleic acid (mRNA) expression level was significantly reduced, and the FOXN1 mRNA expression level increased markedly in the ET-1 + ERß small interfering ribonucleic acid (siRNA) group. Meanwhile, the FOXN1 mRNA expression level was significantly reduced in the ET-1 + FOXN1 siRNA group. FOXN1 promoter luciferase reporter gene activity was notably enhanced in the ERß siRNA group compared with the siRNA control group. Compared with the ET-1 + NC group, the levels of reaction oxygen species (ROS) in the ET-1 + ERß siRNA group increased considerably, the superoxide dismutase (SOD) level was significantly reduced, and the G0/G1 phase cell ratio was reduced. In addition, the protein expression of ERß and cyclin B1 (CCNB1) was markedly reduced, whereas the protein expression of cyclin A2 (CCNA2), cyclin D1 (CCND1), and cyclin E1 (CCNE1) increased substantially. The opposite result was observed in the ET-1 + FOXN1 siRNA group. CONCLUSIONS: ET-1 can contribute to the expression of ERß and FOXN1. ERß can inhibit the expression of FOXN1 by regulating promoter activity. The ET-1/ERß/FOXN1 signaling pathway is involved in the regulation of oxidative stress and cycle progression in HUVEC. This study provides a new mechanism for the regulation of umbilical vein endothelial cells. The ET-1/ERß/FOXN1 signaling pathway may provide novel therapeutic targets and strategies for the treatment of atherosclerosis.

17ß-estradiol inhibits H2O2-induced senescence in HUVEC cells through upregulating SIRT3 expression and promoting autophagy.

17ß-estradiol (17ß-E2) has been implicated in inhibiting the senescence of vascular endothelial cells (VEC) and slowing down the process of atherosclerosis. However, the underlying molecular mechanisms are still unknown. In this study, we examined the roles of SIRT3 in 17ß-E2-induced autophagy and 17ß-E2-mediated inhibition of hydrogen peroxide (H2O2)-induced senescence in Human umbilical vein endothelial cells (HUVEC). Cellular senescence was measured by immunoblot analysis with antibodies against phosphorylated Rb and senescence-associated ß-galactosidase staining. Immunoblot analysis with antibodies against LC3 and p62 was performed to determine autophagy flux. Our findings show that 17ß-E2 activates SIRT3 promoter and upregulates SIRT3 gene expression in HUVEC cells. siRNA-mediated silencing of SIRT3 gene expression inhibits 17ß-E2-induced processing of LC3-I to LC3-II and degradation of p62, two widely-used makers of autophagy. SIRT3 knockdown also blocks 17ß-E2-induced inhibition of cellular senescence triggered by H2O2. Our data further reveal that SIRT3 knockdown impairs 17ß-E2-induced co-localization of LC3 and VDAC1, a marker protein on mitochondria, when HUVEC cells were co-treated with H2O2. Together, our findings suggest that 17ß-E2 upregulates SIRT3 gene expression by activating SIRT3 promoter and then promotes autophagy, which in turn serves to remove dysfunctional mitochondria caused by H2O2 and consequently inhibit H2O2-induced senescence in HUVEC cells.

Resveratrol attenuates hydrogen peroxide-induced aging through upregulation of autophagy in human umbilical vein endothelial cells.

PURPOSE: Resveratrol (RESV; trans-3,5,4'-trihydroxystilbene) has emerged as a potential new therapeutic for age-related atherosclerotic diseases. However, the effect of RESV on cellular aging and its underlying mechanisms remain unknown. Therefore, the aim of this study was to examine whether RESV can delay cellular aging through upregulation of autophagy. MATERIALS AND METHODS: Human umbilical endothelial vein cells (HUVECs) were divided into four groups: the control group, and the hydrogen peroxide (H2O2) alone, H2O2 + RESV pretreatment, and H2O2 + 3-methyladenine (3-MA) + RESV pretreatment intervention groups. The cell viability was evaluated by a cell counting kit-8 assay. Superoxide dismutase (SOD) activity and intracellular reactive oxygen species (ROS) levels were tested using commercial kits. Senescence-related ß-galactosidase activities were detected by immunohistochemical staining. The expression levels of aging-related and autophagy-related markers, including phosphorylated Rb (p-Rb), LC3, and p62, with or without RESV were measured by Western blotting. RESULTS: Pretreatment with 10 µM RESV increased the cell viability and SOD levels. The remarkably higher positive rate of senescence-associated ß-galactosidase and increased intracellular ROS levels in the H2O2 treatment group were reversed by treatment with 10 µM RESV. As compared to the H2O2 treatment group, 10 µM RESV could upregulate autophagy through the regulation of p-Rb, LC3, and p62 levels. The anti-aging effect of RESV via an autophagy regulation mechanism was further confirmed by the suppression of these effects with 3-MA treatment. CONCLUSION: RESV may reverse and delay the aging process of HUVECs via upregulation of autophagy and could be a candidate therapeutic for age-related atherosclerotic diseases.

17ß-estradiol inhibits human umbilical vascular endothelial cell senescence by regulating autophagy via p53.

Vascular endothelial cell (VEC) senescence is an initiating factor in numerous cardiovascular diseases. Recent studies showed that 17ß-estradiol (17ß-E2), an estrogen with numerous biological activities such as inhibition of atherosclerosis, protects VECs from senescence. However, the effects of 17ß-E2 on human umbilical VECs (HUVECs) remain unknown. This study investigated the anti-senescent effect of 17ß-E2 on HUVECs and explored the underlying mechanism with respect to autophagy and p53 activity. First, rapamycin and 3-methyladenine were used to clarify the relationship between autophagy and senescence in HUVECs, and an inverse relationship was demonstrated. Next, the effect of 17ß-E2 on H2O2-induced senescence of HUVECs was examined. Increased autophagy induced by 17ß-E2 inhibited H2O2-induced senescence of HUVECs, increased cell viability, and maintained HUVEC morphology. 17ß-E2 pre-treatment also decreased cell cycle arrest, decreased the dephosphorylation of Rb, decreased the production of ET-1, and increased the production of NO. Most importantly, 17ß-E2 pre-treatment increased autophagy by activating p53 and its downstream effector p53-upregulated modulator of apoptosis (PUMA). Overall, our data indicate the critical role of autophagy in the anti-senescent effect of 17ß-E2 on HUVECs.

Low bone mineral density is associated with global coronary atherosclerotic plaque burden in stable angina patients.

BACKGROUND: Accelerated atherosclerosis is considered to be the linking factor between low bone mineral density (BMD) and increased cardiovascular events and mortality, while some coronary angiographic studies do not support this point. In this study, we attempt to provide a distinct comprehensive view of the relationship between BMD and the angiographically determined coronary atherosclerotic burden. METHODS: A total of 459 consecutive patients with stable chest pain suspected of coronary artery disease (CAD) underwent both dual-energy X-ray absorptiometry scan and selective coronary angiography. The association between BMD and global coronary atherosclerotic plaque burden as represented by the multivessel involvement and the modified Gensini score was analyzed. RESULTS: Multivariable analysis revealed that the low BMD at femoral neck and total hip was an independent correlate of multivessel CAD. The T-scores measured at femoral neck and total hip were both negatively and independently associated to the modified Gensini score. These inversely correlated relationships between BMD and CAD were not observed at lumbar spine 1-4. CONCLUSION: This cross-sectional study elucidated an inverse relationship between hip BMD and the modified Gensini score, and low hip BMD values (T-scores) were significantly and independently associated with increased risk of multivessel coronary disease in patients hospitalized for stable chest pain.

Long noncoding RNA LINC00339 aggravates doxorubicin-induced cardiomyocyte apoptosis by targeting MiR-484.

Abnormally expressed long noncoding RNAs (lncRNAs) has been recognized as one of the key source in cardiac diseases. However, the role of lncRNA in doxorubicin (DOX)-induced cardiotoxicity remains largely unknown. In previous studies, we have screened some aberrantly expressed lncRNAs from an animal model for DOX-induced cardiotoxicity, and LINC00339 is one of the highly expressed lncRNA. In this study, we validated and further explored its regulatory mechanisms using in vitro model systems. Primary cultured myocardial cell (PC) and H9C2 cell line were treated with different concentrations of DOX and the expression of LINC00339 were markedly up-regulated. However, knockdown of endogenous LINC00339 by its siRNA improved cells proliferation activity and reduced cardiomyocyte apoptosis. Further experiments showed the opposite trend of expression between LINC00339 and miR-484. Bioinformatics analysis and luciferase reporter assay indicated that LINC00339 directly binds to miR-484. Moreover, miR-484 inhibitor abrogated the collagen synthesis inhibition induced by LINC00339. These findings reveal a novel function of the LINC00339/miR-484 axis in DOX-induced cardiotoxicity.

[Polydatin inhibits cell proliferation and expressions of inflammatory cytokines in THP-1 cells induced by ox-LDL via up-regulating SIRT1].

Objective To investigate the effects of polydatin on cell proliferation and cytokine expression in THP-1 monocyte-derived macrophages (MDMs) induced by oxidized low-density lipoprotein (ox-LDL), and the possible mechanisms. Methods MDMs were divided into the control group (only treated with ordinary culture medium), ox-LDL group (treated wtih 80 µmol/L ox-LDL for 24 hours), polydatin treatment group (treated with 100 µmol/L polydatin for 2 hours prior to the treatment with 80 µmol/L ox-LDL for 24 hours) and EX-527 treatment group (treated with 10 µmol/L SIRT1 inhibitor EX-527 for 2 hours prior to the treatment with ox-LDL and polydatin). The effects of polydatin on ox-LDL-induced oxidative proliferation and cytokine expression in MDMs were evaluated by CCK-8 assay. Spectrofluorometry was used to determine the intracellular level of superoxide dismutase (SOD) and malondialdehyde (MDA). DCFH-DA loading was used to detect the content of reactive oxidative species (ROS). The levels of silent mating type information regulator 1 (SIRT1), monocyte chemoattractant protein-1 (MCP-1), tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) were examined by real-time quantitative PCR and Western blotting. Results Polydatin (100 µmol/L) inhibited the proliferation of MDMs induced by ox-LDL, decreased the levels of MDA and ROS, whereas the level of SOD increased. The mRNA and protein levels of SIRT1 in MDMs were inhibited by ox-LDL, whereas the expressions of MCP-1, TNF-α and IL-6 were promoted. Pre-treatment with EX-527 attenuated the inhibitory effects of polydatin on the proliferation of MDMs, inhibited the expressions of SIRT1, promoted the expressions of MCP-1, TNF-α and IL-6. Conclusion Polydatin up-regulates the expression of SIRT1 to increase the ability of anti-macrophage proliferation, reduce the level of the intracellular ROS induced by ox-LDL, and inhibit the expression of inflammatory cytokines.

Pramipexole pretreatment attenuates myocardial ischemia/reperfusion injury through upregulation of autophagy.

This article investigated the effects of pramipexole on myocardial ischemia reperfusion (I/R) injury and its underlying mechanisms. We utilized an in vivo mouse model of myocardial I/R injury and an in vitro H9c2 cell model of hypoxia/reoxygenation (H/R) injury. Pramipexole pretreatment in male C57BL/6 mice significantly reduced the myocardial infarction size, decreased the CK and LDH activities at the serum level and enhanced autophagy. In the in vitro study, the pramipexole treatment significantly elevated the survival rate, decreased the LDH activity, reduced ROS generation and restored the ΔΨm in H9C2 cells during H/R. Additionally, its use could increase the autophagy flux level in H9c2 cells. The underlying mechanisms were determined by measuring the expression of the autophagic protein levels. These results further indicated that pramipexole treatment modulated H/R-induced autophagy via an AMPK-dependent pathway. All of these data indicate that pramipexole exerted protective effects against myocardial I/R injury and enhanced autophagy in part through the AMPK-mediated pathway.

Polydatin inhibits the oxidative stress-induced proliferation of vascular smooth muscle cells by activating the eNOS/SIRT1 pathway.

Oxidative stress-mediated proliferation of vascular smooth muscle cells (VSMCs) contributes to plaque formation and the progression of atherosclerosis. Polydatin is a derivative of resveratrol, and is widely present in certain herbal medications used for the treatment of cardiovascular diseases. In the present study, we examined whether polydatin was capable of attenuating VSMC proliferation induced by oxidative stress as well as the potential involvement of the endothelial nitric oxide synthetase (eNOS)/SIRT1 pathway. Briefly, VSMCs were exposed to H2O2 for 24 h in the absence or presence of polydatin (10-100 µM) prior to performing a cell proliferation assay. In mechanistic studies, the cells were incubated with the silent information regulator 1 (SIRT1) inhibitor, EX527, or the eNOS inhibitor, L-NAME, prior to polydatin treatment. The results showed that polydatin inhibited VSMC proliferation and the level of reactive oxygen species, increased the expression of Kip1/p27, SIRT1 and eNOS, whereas the expression of cyclin B1, Cdk1 and c-myc was decreased. The number of cells in the G2/M phase was increased. Pre-treatment with L-NAME attenuated the inhibitory effects of polydatin on cell proliferation, inhibited the expression of SIRT1 and the phosphorylation of eNOS. Pre-treatment with EX527 also attenuated the inhibitory effects of polydatin on cell proliferation, but failed to reduce the activation of eNOS and the production of nitric oxide. Taken together, these findings suggest that, polydatin inhibited the oxidative stress-induced proliferation of VMSCs by activating the eNOS/SIRT1 pathway.

Retarding the senescence of human vascular endothelial cells induced by hydrogen peroxide: effects of 17beta-estradiol (E2) mediated mitochondria protection.

This study investigates the influence of 17beta-estradiol (E2) on hydrogen peroxide (H2O2)-induced human vascular endothelial cell (HUVEC) senescence. HUVECs were divided into four groups, namely control group, H2O2 stimulation group, E2 intervention group and ICI182780 (ICI) intervention group. The aging-related ß-galactosidase activities, cytochrome C oxidase activities, intracellular ATP levels, intracellular reactive oxygen species (ROS) levels and phosphorylated Rb protein expressions were mainly observed. Of which, senescence-associated ß-galactosidase activities were detected using immunohistochemical staining, cytochrome C oxidase activities and intracellular ATP levels were detected using commercial kits, ROS levels were detected by fluorescence microscopy and fluorescence microplate reader, immunoblotting was used to quantitatively detect the expressions of phosphorylated Rb proteins. After continuous treatment of H2O2, the senescent phenotypes appeared in the HUVECs. The percentage of positive SA-ßgal staining cells and the phosphorylated Rb expressions were significantly increased; intracellular ROS levels, cytochrome C oxidase activities and intracellular ATP levels were elevated. Compared with the H2O2 stimulation group, E2 intervention significantly decreased the positive rate of SA-ß-gal staining, the phosphorylated Rb protein levels, the intracellular ROS levels, cytochrome C oxidase activities and intracellular ATP levels. Pretreatment of estrogen receptor blocker ICI182780 weakened the role of E2. These results indicated that H2O2 could induce HUVEC senescence; 17beta-E2 might relieve H2O2-induced mitochondrial damage through estrogen receptor and delay the vascular endothelial cell senescence.

Long-term atorvastatin improves age-related endothelial dysfunction by ameliorating oxidative stress and normalizing eNOS/iNOS imbalance in rat aorta.

Vascular aging is characterized by vascular cell senescence, increased oxidative stress, and endothelial and inducible nitric oxide (NO) synthase (eNOS/iNOS) imbalance, which reduces NO bioavailability and causes endothelial dysfunction. We investigated whether long-term administration of atorvastatin affects endothelial dysfunction and the underlying mechanisms. Aortas from young (2 months), middle-aged (12 months), and old (20 months) control rats that had received a routine diet and from old rats (20 months) that had received a diet mixed with atorvastatin (5 mg/kg/day) for 8 months were investigated. Senescent phenotype, vascular reactivity, superoxide dismutase (SOD), malonyldialdehyde (MDA), total NO, calcium-dependent and -independent NOS activity, and eNOS, iNOS, and sirtuin-1 (SIRT1) expression at the transcriptional and translational levels were assessed in rat aortas. Comparisons between young, middle, and old control rats showed that the senescent phenotype was enhanced in intima and media (p<0.01), and that MDA, calcium-independent NOS activity, and iNOS increased with age (p<0.01), whereas endothelium-dependent relaxation, SOD, NO, calcium-dependent NOS activity, eNOS, the eNOS/iNOS ratio, and SIRT1 declined with age (p<0.01). Compared with old controls, long-term administration of atorvastatin to old rats inhibited the senescent phenotype (p<0.05), improved endothelium-dependent relaxation (p<0.05 or 0.01), decreased MDA (p<0.01), increased SOD, NO, eNOS, and SIRT1 expression (p<0.01), and inhibited iNOS expression (not detectable) in aged rat aortas. The results indicate that the long-term administration of atorvastatin improves age-related endothelial dysfunction in aged rats via inhibition of the senescent phenotype, amelioration of oxidative stress, and normalization of eNOS/iNOS imbalance.

[Effects of policosanol combined with simvastatin on serum lipids and sex hormones in male patients with hyperlipidemia].

OBJECTIVE: To evaluate the effects and safety of policosanol combined with simvastatin on serum lipids and sex hormones in male patients with hyperlipidemia. METHODS: This randomized, single-blinded, placebo-controlled study included 120 male patients with hyperlipidemia. Patients were divided randomly into treatment group(n = 60) and control group(n = 60). Patients in the treatment group were administrated with simvastatin (40 mg/d) plus policosanol (20 mg/d),and those in the control group were treated with simvastatin (40 mg/d) plus placebo (20 mg/d). The values of total cholesterol(TC), triglyceride(TG), high density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol(LDL-C), testosterone(T) and estradiol (E2) were assessed before and after 16 weeks treatment.Drug-induced adverse effects were observed. RESULTS: Baseline characteristics were similar between groups. TC,TG, LDL-C were (5.74 ± 0.99) , (1.62 ± 0.69), (3.60 ± 0.56) mmol/L in the treatment group at baseline and significantly reduced after 16 weeks treatment (4.57 ± 0.58), (1.54 ± 0.55), (2.68 ± 0.38) mmol/L (all P < 0.05). TC, LDL-C were (5.99 ± 0.93) , (3.76 ± 0.42) mmol/L in the control group at baseline and significantly reduced after 16 weeks treatment (5.03 ± 0.59) , (2.98 ± 0.28) mmol/L (all P < 0.05) while TG remained unchanged post 16 weeks therapy in the control group. Simvastatin plus policosanol achieved a significantly greater reduction in LDL-C and TC than simvastatin plus placebo (P < 0.05). HDL-C,T and E2 were similar before and after 16 weeks treatments in both groups (P > 0.05) .The adverse reactions were similar between the two groups, most of them were mild and happened at the beginning of drug therapy and could be well tolerated. CONCLUSION: Simvastatin/policosanol produces greater decreases in TC, LDL-C than simvastatin/placebo without resulting more side effects and changes on sex hormones.

[Effect of hydrogen sulfide on H2O2-stimulated primary neonatal rat cardiomyocytes].

OBJECTIVE: To investigate the effects of hydrogen sulfide (H2S) on H2O2-stimulated primary neonatal rat cardiomyocytes and related mechanism. METHODS: Primary neonatal rat cardiomyocytes were treated with various concentrations of H2O2 (10, 100, 1000 µmol/L) for 24 h to establish the oxidative stress-induced cell injury model after 3 days' conventional culture. In addition, different concentrations of NaHS (1, 10, 100 µmol/L) were added to cardiomyocytes in the absence and presence of 100 µmol/L H2O2 for 24 h. The viability of cardiomyocytes was measured by MTT assay. The SOD vitality was measured by xanthine oxidase method and MDA content was determined by thiobarbituric acid colorimetric method. LDH activity was measured by chemical colorimetric method. The percentage of apoptotic cells was assessed by flow cytometry (FCM). The mitochondrial membrane potential (MMP) was analyzed by rhodamine 123 (Rh123) staining and photofluorography. The level of reactive oxygen species (ROS) in cardiomyocytes was measured by DCFH-DA staining and photofluorography. RESULTS: Cell viability and SOD vitality were significantly reduced while MDA content and LDH activity were significantly increased with increasing H2O2 concentrations. These effects could be partly reduced by cotreatment with H2O2 in a concentration-dependent manner (all P < 0.05). Compared with control group, the DCF fluorescence intensity significantly increased in the 100 µmol/L H2O2 group (P = 0.003), which could be attenuated by NaHS in a dose-dependent manner. Compared with control group, the MMP significantly decreased in the 100 µmol/L H2O2 group (P = 0.000), which could be partly reversed by cotreatment with NaHS in a dose-dependent manner. Moreover, H2O2 treatment also significantly reduced 100 µmol/L H2O2 induced apoptosis in a dose-dependent manner. CONCLUSION: H2S protects primary neonatal rat cardiomyocytes against H2O2-induced oxidative stress injury through inhibition of H2O2 induced overproduction of ROS, dissipation of MMP and apoptosis.

Physiological testosterone retards cardiomyocyte aging in Tfm mice via androgen receptor-independent pathway.

OBJECTIVE: To determine whether testosterone modulates markers of cardiomyocytes aging via its classic androgen receptor (AR)-dependent pathway or conversion to estradiol. METHODS: Male littermates and testicular feminized (Tfm) mice were randomly separated into 4 experimental groups littermate controls (n=8), Tfm mice (n=7), testosterone-treated Tfm mice (n=8), and Tfm mice treated with testosterone in combination with the aromatase inhibitor anastrazole (n=7). Cardiomyocytes were isolated from mouse left ventricles, the activity of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), and the amount of malondialdehyde (MDA) were measured using colorimetry method, and expression of p16(INK4α) and retinoblastoma (Rb) proteins were detected by Western blotting. RESULTS: The SOD and GSH-Px enzyme activities of cardiomyocytes were decreased, and the MDA levels and the expression of p16(INK4α) and Rb proteins were increased in Tfm mice compared with control mice. An increase was observed in the activities of SOD and GSH-Px enzyme as well as a decrease in MDA levels and the expression of p16(INK4α) and Rb proteins in the testosterone-treated Tfm mice. After co-treatment with anastrazole in Tfm mice, these improvement were partly inhibited. CONCLUSION: Physiological testosterone replacement can delay cardiomyocyte aging in Tfm mice, an effect that is independent of the AR pathway and in part conversion to estradiol.

[Occurrence and prognosis of coronary slow flow in emergency percutaneous coronary intervention: correlations with homocysteine].

OBJECTIVE: To investigate the correlation of the occurrence and prognosis of coronary slow flow phenomenon (CSF) with blood homocysteine (Hcy) levels in patients receiving emergency percutaneous coronary intervention therapy (PCI). METHODS: From January, 2010 to December, 2011, 138 patients with ST-elevation myocardial infarction received emergency angioplasty, among whom 46 patients developed CSF and 92 did not (control group). Blood Hcy levels were determined in these patients. The patients with CSF were classified into two groups with mild and moderate Hcy elevations (32 and 14 cases, respectively), and the left ventricular ejection fraction (LVEF) during hospitalization and at 3 months of follow-up as well as major adverse cardiac events (MACE) were compared between the two groups and analyzed for their association with Hcy level. RESULTS: The patients with CSF showed significantly higher blood Hcy levels than the control patients (P=0.001). At 3 months of follow-up, the patients with CSF and moderate Hcy elevation had significantly lower LVEF (P=0.031) and higher incidence of MACE (P=0.019) than those with mild Hcy elevation. Hcy levels were negatively correlated with LVEF (r=-0.310, P=0.036) and positively with MACE (r=0.342, P=0.02). CONCLUSION: A high blood Hcy level is closely correlated with the occurrence of CSF in emergency PCI, affects the recovery of LVEF and increases the incidence of MACE.

Testosterone suppresses oxidative stress via androgen receptor-independent pathway in murine cardiomyocytes.

Evidence supports that oxidative stress exerts significant effects on the pathogenesis of heart dysfunction. On the other hand, the presence of specific androgen receptor (AR) in mammalian cardiomyocytes implies that androgen plays a physiological role in cardiac function, myocardial injury and the regulation of the redox state in the heart. This study used the testicular feminized (Tfm) and castrated male mice to investigate the effects of testosterone deficiency, physiological testosterone therapy and AR on oxidative stress in cardiomyocytes. Tfm mice have a non-functional AR and reduced circulating testosterone levels. Male littermates and Tfm mice were separated into 5 experimental groups: non-castrated littermate controls, castrated littermates, sham-operated Tfm, testosterone-treated castrated littermates and testosterone-treated sham-operated Tfm mice. Cardiomyocytes that were isolated from the left ventricle were used for determination of superoxide dismutase (SOD), glutathione peroxidase (GSH­Px) enzyme activities, and malondialdehyde (MDA) levels. Additionally, mitochondrial DNA (mtDNA) deletion mutations were detected by nested PCR. The SOD and GSH-Px enzyme activities of cardiomyocytes were decreased, and the MDA levels and the proportion of mtDNA mutations were increased in castrated and sham-operated Tfm mice compared to control mice. However, an increase was observed in the activities of SOD and GSH-Px enzyme as well as a decrease in MDA levels and the proportion of mtDNA mutations in the mice that had received testosterone therapy. These changes were statistically similar in castrated and sham-operated Tfm mice after testosterone therapy. In conclusion, it is testosterone deficiency that induces oxidative stress in cardiomyocytes. Physiological testosterone therapy is able to suppress oxidative stress mediated via the AR-independent pathway.

[Effect of physiological doses of testosterone on mitochondrial DNA deletion in castrated mice].

OBJECTIVE: To evaluate the effect of physiological doses of testosterone on mitochondrial DNA (mtDNA) deletion in the aortic vascular wall of castrated C57BL/6J mice. METHOD: Twenty-four male C57BL/6J mice were randomized into normal control group (n=8), castrated+placebo group (castrated group, n=8), and castrated+physiological doses (1 mg/kg every 3 days) of testosterone group (n=8). The mice were fed normally for 3 months along with 8 mice with natural aging (18 months old), after which blood samples were obtained from all the groups for measurement of testosterone concentrations. The aortic mtDNA was extracted to analyze the deleted fragments using nested PCR, and fragments with deletions were purified and identified by sequence analysis. RESULTS: Compared with the normal control group, the castrated group showed a significantly higher optical density ratio of the deletions [(18.1713 ∓ 2.4317)% vs (36.8475 ∓ 3.3365)%], but no significant difference was found between the castrated and natural ageing group [(42.3075 ∓ 3.6556)%]. The castrated+testosterone showed a lowered optical density ratio of (23.6488 ∓ 2.7634)% as compared with the castrated and natural ageing group, but a similar one with the normal control group. Sequence analysis identified 4 different types of deletions in the aging aorta at 3713, 3864, 4236, and 4415 bp, and the presence of direct repeats was confirmed to flank the deletions. CONCLUSIONS: Multiple mtDNA deletions occur in ageing mice at a higher rate than in young mice. Testosterone deficiency is associated with increased aortic mtDNA deletions, which can be decreased by physiological doses of testosterone.

[Effects of simvastatin on plasma SOD, MDA and 8-iso-PGF2α in patients with stable angina].

OBJECTIVE: To observe the effects of simvastatin on plasma superoxide dismutase (SOD), malonaldehyde (MDA) and 8-iso-prostaglandin F2α (8-iso-PGF2α) as well as uric acid (UA) and serum lipids in patients with stable angina. METHODS Eighty-five patients with stable angina were divided into 4 groups, including hyperlipemia treatment group (HLT), hyperlipemia control group (HLC), normolipemia treatment group (NLT), and normolipemia control group (NLC). All the patients received routine treatment according to the guideline of CHD treatment, and those in the treatment groups were given Simvastatin (40 mg) every night, whereas those in the control group received placebo for 3 months. Before and after the treatments, the levels of plasma 8-iso-PGF2α were measured by enzyme-linked immunosorbent assay, and the plasma levels of SOD and MDA were detected by colorimetric method. LDL, HDL, TC, TG, and UA were also measured biochemically. RESULTS Compared with the control group, both of the treatment groups showed significantly increased levels of SOD and decreased MDA, 8-iso-PGF2α, UA and plasma lipids after the treatments (P<0.05). CONCLUSION In patients with coronary heart disease, simvastatins can decrease plasma lipids, inhibit lipid peroxidations, and promote the clearance of free radicals, thereby alleviating the oxidative stress.