Fluvastatin attenuated ischemia/reperfusion-induced autophagy and apoptosis in cardiomyocytes through down-regulation HMGB1/TLR4 signaling pathway.

Fluvastatin, a traditional fat-decreasing drug, is widely used for curing cardiovascular disease. Previous reports demonstrated that fluvastatin pretreatment protected against myocardial ischemia/reperfusion (I/R) by inhibiting TLR4 signaling pathway and/or reducing proinflammatory cytokines. However, whether fluvastatin has a cardioprotective effect against apoptosis and autophagy remains unknown. This study aims to evaluate whether the cardioprotective role of fluvastatin in I/R is mediated by high-mobility group box 1 (HMGB1)/toll-like receptor 4 (TLR4) pathway via anti-apoptotic and anti-autophagic functions. Sprague-Dawley rats were anesthetized, artificially ventilated and subjected to 30 min of coronary occlusion, followed by 4 h of reperfusion. The animals were randomized into four groups: (i) Sham operation; (ii) I/R; (iii) I/R + low-dosage fluvastatin (10 mg/kg); and (iv) I/R + high-dosage fluvastatin (20 mg/kg). After reperfusion, the hemodynamic parameters, myocardial infarct size, structural alteration of myocardium, apoptosis index, pro-inflammatory cytokine production, Beclin-1, Light chain 3 (LC3), HMGB1, TLR4 and Nuclear factor kappa B (NF-κB) protein levels were measured and recorded. It was found that fluvastatin preconditioning improved left ventricular dysfunction, reduced HMGB1/TLR4/NF-κB expressions, and inhibited cardiomyocyte apoptosis, autophagy, and inflammation reaction. Moreover, treatment with fluvastatin ameliorated myocardial injury by reducing infarct size, causing less damage to cardiac structure, downregulating autophagy-related protein expression and releasing pro-inflammation mediators. Our findings indicate that fluvastatin exerts beneficial effects on cardiac ischemic damage, which may be associated with its anti-autophagic and anti-apoptotic functions via inhibition of HMGB1/TLR4-related pathway during I/R injury.

The Role of α7nAChR-Mediated Cholinergic Anti-Inflammatory Pathway in Vagal Nerve Regulated Atrial Fibrillation.

The aim was to investigate the role of the α7nAChR-mediated cholinergic anti-inflammatory pathway in vagal nerve regulated atrial fibrillation (AF).18 beagles (standard dogs for testing) were used in this study, and the effective refractory period (ERP) of atrium and pulmonary veins and AF inducibility were measured hourly during rapid atrial pacing at 800 beats/minute for 6 hours in all beagles. After cessation of 3 hours of RAP, the low-level vagal nerve stimulation (LL-VNS) group (n = 6) was given LL-VNS and injection of salinne (0.5 mL/GP) into four GPs, the methyllycaconitine (MLA, the antagonist of α7nAChR) group (n = 6) was given LL-VNS and injection of MLA into four GPs, and the Control group (n = 6) was given saline into four GPs and the right cervical vagal nerve was exposed without stimulation. Then, the levels of the tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), acetylcholine (ACh), STAT3, and NF-κB proteins were measured. During the first 3 hours of RAP, the ERPs gradually decreased while the dispersion of ERPs (dERPs) and AF inducibility gradually increased in all three groups. During the last 3 hours of 6 hours' RAP in this study, the ERPs in the LL-VNS group were higher, while the dERPs and AF inducibility were significantly lower when compared with the Control and MLA groups at the same time points. The levels of ACh in the serum and atrium in the LL-VNS and MLA groups were higher than in the Control group, and the levels of TNF-α and IL-6 were higher in the Control and MLA groups than in the LL-VNS group. The concentrations of STAT3 in RA and LA tissues were higher in the LL-VNS group while those of NF-κB were lower.In conclusion, the cholinergic anti-inflammatory pathway mediated by α7nACh plays an important role in low-level vagal nerve-regulated AF.

Regulator of G-protein signalling 5 deficiency impairs ventricular remodelling after myocardial infarction by promoting NF-κB and MAPK signalling in mice.

Regulator of G-protein signalling 5 (RGS5) is, highly expressed in different cell types of the adult human heart, and it is a negative regulator of G protein-mediated signalling that inactivates Gα(q) and Gα(i) and thereby inhibits many signalling pathways. However, the critical role of RGS5 in the pathology of myocardial infarction (MI) remains unexplored. Here, an in vitro MI model, induced by the permanent ligation of the left anterior descending coronary artery, was used with the isolated hearts of wild type (WT) and RGS5-knockout (KO) mice. Our results showed that the loss of RGS5 decreased the post-MI survival rate and left ventricular (LV) function and increased the infarct size. Additionally, the RGS5 knockout mice exhibited greater inflammation, apoptosis, and ventricular remodelling compared with WT-MI mice. Mechanistically, RGS5 loss activated the pathological response mainly by affecting the NF-κB and MAPK signalling pathways. Therefore, our data strongly indicate that RGS5 is a novel modulator of pathological progression after MI that functions NF-κB and MAPK signalling.

Gene and stem cell therapy for inherited cardiac arrhythmias.

Inherited cardiac arrhythmias are a group of genetic diseases predisposing to sudden cardiac arrest, mainly resulting from variants in genes encoding cardiac ion channels or proteins involved in their regulation. Currently available therapeutic options (pharmacotherapy, ablative therapy and device-based therapy) can not preclude the occurrence of arrhythmia events and/or provide complete protection. With growing understanding of the genetic background and molecular mechanisms of inherited cardiac arrhythmias, advancing insight of stem cell technology, and development of vectors and delivery strategies, gene therapy and stem cell therapy may be promising approaches for treatment of inherited cardiac arrhythmias. Recent years have witnessed impressive progress in the basic science aspects and there is a clear and urgent need to be translated into the clinical management of arrhythmic events. In this review, we present a succinct overview of gene and cell therapy strategies, and summarize the current status of gene and cell therapy. Finally, we discuss future directions for implementation of gene and cell therapy in the therapy of inherited cardiac arrhythmias.

Effects of endothelin-1 chronic stimulation on electrical restitution, beat-to-beat variability of repolarization, and ventricular arrhythmogenesis.

Chronically elevated levels of endothelin-1 (ET-1) have been detected in several cardiovascular diseases. In this study, we investigated the chronic effects of ET-1 on the electrophysiological characteristics expected to influence the genesis and maintenance of ventricular arrhythmia (VA). Rabbits were randomized to ET-1 (ET-1 group) or 0.9% saline (control group) for 2 weeks. The S1-S2 protocol and S1-S1 dynamic pacing were performed to assess the action potential duration restitution (APDR) and to induce APD alternans or VA in 4 sites of Langendorff-perfused rabbit hearts. The beat-to-beat variability of repolarization was quantified as short-term variability and long-term variability. Compared with the control group, chronic ET-1 administration significantly prolonged QT intervals, APD at 90% repolarization (APD90), and effective refractory period (ERP), steepened the maximum slopes of the APDR curve, decreased the ERP/APD90 ratio, and increased the spatial dispersions of APD90, ERP, and maximum slopes (P < 0.05 for all). Moreover, chronic ET-1 administration markedly increased the short-term variability and long-term variability (P < 0.01 for all). APD alternans occurred in both groups, but the threshold of APD alternans was decreased at all sites in the ET-1 group (P < 0.01 for all). We also observed that chronic ET-1 stimulation significantly increased the incidence and duration of the VA episodes. These results suggest that chronic stimulation with ET-1 facilitated VA by steepening the APDR curve and increasing the spatial dispersion of APDR and beat-to-beat variability of repolarization.

Ginsenoside Rh2 attenuates myocardial ischaemia­reperfusion injury by regulating the Nrf2/HO­1/NLRP3 signalling pathway.

Ginsenoside Rh2 (GRh2) is a monomer isolated from red ginseng that has extensive pharmacological effects. However, whether GRh2 has a protective effect on ischaemia/reperfusion (I/R) in the myocardium has yet to be elucidated. The present study aimed to identify the anti-inflammatory and antioxidant effects of GRh2 on I/R in the myocardium and its underlying mechanism. A rat model of myocardial I/R injury was constructed by ligating the left anterior descending coronary artery, which was subsequently treated with GRh2. A total of 40 male Sprague-Dawley rats were divided into the following four groups: The sham group, the I/R group, the I/R+GRh2 (10 mg/kg) group and the I/R+GRh2 (20 mg/kg) group. Neonatal rat cardiomyocytes were also used to evaluate the protective effect of GRh2 on hypoxia/reoxygenation (H/R)-induced myocardial injury in vitro. The GRh2 pre-treatment reduced the I/R- or H/R-induced release of myocardial enzymes and the production of IL-1ß, IL-18 and TNF-α. GRh2 reduced the area of myocardial infarction and the histological changes in the myocardium and improved cardiac functions. In addition, GRh2 reduced the expression levels of NOD-like receptor family pyrin domain-containing 3 (NLRP3), apoptosis-associated speck-like protein, caspase-1, malondialdehyde and reactive oxygen species and increased the expression levels of nuclear factor E2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), glutathione peroxidase and superoxide dismutase. In conclusion, the present study confirmed that GRh2 could reduce oxidative stress and inflammation in cardiomyocytes after reperfusion, and its mechanism of action may be related to its regulation of the Nrf2/HO-1/NLRP3 signalling pathway.

Macrophage colony-stimulating factor ameliorates myocardial injury in mice after myocardial infarction by regulating cardiac macrophages through the P2X7R/NLRP3/IL-1ß signal pathway.

Aims: To investigate the effects of M-CSF on myocardial injury in mice after MI by regulating different types of cardiac macrophages through the P2X7R/NLRP3/IL-1ß signal pathway. Methods: A total of 60 C57BL/6J WT mice were used, with the Sham Group subjected to ligation without ligation through the LAD, the MI model was prepared by ligation of the LAD in the MC Group and MM Group, with the M-CSF reagent (500 µg/kg/d) being given an intraperitoneal injection for the first 5 days after surgery in the MM Group. All mice were fed in a barrier environment for 1 week. After the study, myocardial tissues were collected and IL-4, IL-6, IL-10, TNF-α, MCP-1, IFN-α, ANP, BNP, ß-MHC, Collage I, Collage III, P2X7R, NLRP3, IL-1ß, Bax, Caspase 3, C-Casp 3, Bcl-2, M1/2 macrophage, the apoptosis of cardiomyocytes, and the collagen deposition were detected. Results: The inflammatory response was significantly lower in the MM Group, the cardiomyocyte apoptosis, fibrosis, and hypertrophy were inhibited compared to the MC Group, and the levels of P2X7R, NLRP3, and IL-1ß were also statistically lower in the MM Group. Additionally, the expression of M2 macrophages increased in the MM Group while the M1 macrophages statistically decreased compared to the MC Group. Conclusion: M-CSF can significantly increase the expression of M2 macrophage and reduce the level of M1 macrophage by inhibiting the levels of NLRP3/IL-1ß-related proteins, thereby inhibiting inflammation, ameliorating reducing myocardial hypertrophy, apoptosis, and fibrosis, improve myocardial injury in mice after MI.

Advances in basic and translational research in atrial fibrillation.

Atrial fibrillation (AF) is a very common cardiac arrhythmia with an estimated prevalence of 33.5 million patients globally. It is associated with an increased risk of death, stroke and peripheral embolism. Although genetic studies have identified a growing number of genes associated with AF, the definitive impact of these genetic findings is yet to be established. Several mechanisms, including electrical, structural and neural remodelling of atrial tissue, have been proposed to contribute to the development of AF. Despite over a century of exploration, the molecular and cellular mechanisms underlying AF have not been fully established. Current antiarrhythmic drugs are associated with a significant rate of adverse events and management of AF using ablation is not optimal, especially in cases of persistent AF. This review discusses recent advances in our understanding and management of AF, including new concepts of epidemiology, genetics and pathophysiological mechanisms. We review the current status of antiarrhythmic drug therapy for AF, new potential agents, as well as mechanism-based AF ablation. This article is part of the theme issue 'The heartbeat: its molecular basis and physiological mechanisms'.

Analysis of Na(+)/Ca (2+) exchanger (NCX) function and current in murine cardiac myocytes during heart failure.

Na(+)/Ca(2+) exchanger (NCX) plays important roles in cardiac electrical activity and calcium homeostasis. NCX current (I(NCX)) shows transmural gradient across left ventricle in many species. Previous studies demonstrated that NCX expression was increased and transmural gradient of I(NCX) was disrupted in failing heart, but the mechanisms underlying I(NCX) remodeling still remain unknown. In present study, we used patch clamp technique to record I(NCX) from subepicardial (EPI) myocytes and subendocardial (ENDO) myocytes isolated from sham operation (SO) mice and heart failure (HF) mice. Our results showed that I(NCX) was higher in normal EPI cells compared with that in ENDO, whatever for forward mode or reverse mode. In HF group, I(NCX) was significantly up-regulated, but EPI-ENDO difference was disrupted because of a more increase of I(NCX) in ENDO myocytes. In order to explore the molecular mechanism underlying remodeling of I(NCX) in failing heart, we detected the protein expression of NCX1 and Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) by Western blot. We found that CaMKII activity was dramatically enhanced and parallel with the expression of NCX1 in failing heart. Our study demonstrated that transmural gradient of I(NCX) existed in murine left ventricle, and increased activity of CaMKII should account for I(NCX) remodeling in failing heart.

Cardiac electrophysiological differences between Kunming and C57BL6/J mice.

OBJECTIVE: To investigate the alterations of cardiac electrophysiological properties and substantial mechanism and find the stable arrhythmia mouse model in Kunming (KM) and C57BL6/J (C57) mice. METHODS: Electrocardiogram recordings were used to analyze the QT interval in vivo, and mono- phasic action potential of right and left ventricular epicardium was recorded to elicit changes of action potential duration (APD) in conventional and programmed electrical stimulation (PES). Transient outward potassium current (Ito) was recorded via whole-cell patch-clamp technique in single right and left epicardial myocytes. RESULTS: QT interval was prolonged in KM mice relative to C57 mice (62.51±4.47 ms vs. 52.59±4.85 ms, P<0.05) The APD at 50% repolarization of the left ventricular epicardium (18.60±0.91 ms vs. 12.90±0.35 ms), and APDs at 50% (17.31±6.05 ms vs. 12.00±3.24 ms) and 70% repolarization (36.13±5.32 ms vs. 21.95±8.06 ms) of the right ventricular epicardium in KM mice were more sensitive to PES-induced ventricular tachycardia (25%, 3 of 12 hearts), and especially to Burst-induced ventricular tachycardia (50%, 6 of 12 hearts)compared with C57 mice, which were 20% (2 of 10 hearts) and 30% (3 of 10 hearts) respectively. Ito densities both in the left and right ventricular epicardial myocytes from KM mice were significantly decreased compared with C57 mice, respectively (all P<0.01). CONCLUSION: Our data showed that KM mice with the prolonged QT interval and APD are vulnerabilities to ventricular arrhythmia, which are attributed to lower Ito densities in ventricular myocytes obtained from KM mice than that from C57 mice.

[Effects of renal sympathetic denervation on inducibility of atrial fibrillation during rapid atrial pacing].

OBJECTIVE: To explore the effects of renal sympathetic denervation on inducibility of atrial fibrillation (AF) during rapid atrial pacing. METHODS: Thirteen dogs were selected and divided into control group (n=7) and renal artery ablation group (RAA) (n=6). In the control group, the animals were subjected to atrial pacing at 800 beats/min for 7 hours. And atrial effective refractory period (AERP) and induced AF were measured hourly during non-pacing. In the RAA group, after each renal artery ablation, the procedures of pacing and electrophysiological measurement were nearly the same as those in the control group. Blood was collected before and after pacing to measure the levels of rennin, angiotensin AngII (AngII) and aldosterone. RESULTS: There was a persistent decrease in AERP in both groups. However, after a 7-hour pacing, induced number of times and duration of AF were higher in the control group than those in the RAA group. The plasma concentrations of rennin and aldosterone increased significantly after 7-hour rapid pacing in the control group (rennin: (120±31) to (185±104) pg/ml, P<0.01, aldosterone: (288±43) to (370±110) pg/ml, P=0.01). No significant difference existed in the levels of AngII at pre- and post-pacing in the control group ((160±48) to (189±164) pg/ml, P=0.23). The levels of rennin and aldosterone showed a decreasing trend in the RAA group. But there was no statistical significance. CONCLUSIONS: Episodes of AF during short-time rapid atrial pacing may be decreased by renal sympathetic denervation. This effect is probably related with the decreased activity of RAAS.

[Activating protein kinase C enhances ventricular action potential duration restitution and increase arrhythmia susceptibility in Langendorff-perfused rabbit hearts].

OBJECTIVE: To determine effects of activating protein kinase C (PKC) on ventricular action potential duration restitution (APDR) and Burst stimulus induced arrhythmia in Langendorff-perfused rabbit hearts. METHODS: Male rabbits were equally divided into three groups randomly: control group (Tyrode's solution perfusion), PKC agonist phorbol-12-myristate-13-acetate (PMA, 100 nmol/L) group and PKC inhibitor bisindolylmaleimide (BIM, 500 nmol/L) group. Thirty minutes after perfusion, the monophasic action potential (MAP) and effective refractory period (ERP) were determined in right basal ventricle (RB), right apex (RA), left basal ventricle (LB) and left apex (LA) of all the animals, and APDR curve was drawn. Burst stimulus method was used to induce ventricular arrhythmia in perfused rabbit hearts; Real-time PCR was used to detect the mRNA expression of PKC in four different areas of ventricle. RESULTS: Compared with the control group, the ERP, 90% of monophasic action potential duration (MAPD(90)) and ERP/MAPD(90) were significantly shortened (all P < 0.01), the max slopes (S(max)) of APDR curve were significantly steeper (RB: 1.22 ± 0.23 vs. 0.65 ± 0.19; RA: 2.99 ± 0.29 vs. 1.02 ± 0.18; LB: 1.84 ± 0.21 vs. 0.85 ± 0.12; LA: 4.02 ± 0.32 vs.1.12 ± 0.23, all P < 0.01) and the incidences of ventricular arrhythmia were significantly increased in the PMA group. All parameters were similar between the BIM group and the control group (all P > 0.05). CONCLUSION: Activating PKC could enhance the max slopes of APDR curve at various ventricular areas and subsequently increase arrhythmia susceptibility in Langendorff-perfused rabbit hearts.

[Action potential duration restitution and the potential association with ventricular arrhythmia in Langendorff-perfused chronic heart failure rabbit hearts].

OBJECTIVE: To observe the action potential duration restitution (APDR) change and potential association with ventricular arrhythmia (VA) in Langendorff-perfused chronic heart failure rabbit hearts. METHODS: Male rabbits were randomly divided into two groups: control (CTL, n=15) group and chronic heart failure (CHF, n=15) group. CHF was induced by injecting isoproterenol (300 µg×kg(-1) ×d(-1)) for 14 days. Four weeks later, cardiac function and structure change of both groups were assessed by echocardiography. In the whole Langendorff-perfused hearts, the monophasic action potential (MAP) and the effective refractory period (ERP) were recorded from left anterior basal ventricle, left anterior free wall, left anterior apex and left posterior basal ventricle, left posterior free wall and left posterior apex, the APD curves were also constructed in both groups; at the six sites of every isolated heart, the programmed electrical stimulation and burst pacing were used to induce action potential duration (APD) alternans and VA, respectively. RESULTS: Left ventricular ejection was reduced and end-dimension was enlarged in rabbits of CHF group. Compared with the same sites of CTL group, the 90% of MAP duration (MAPD90), the ERP, the max slope (Smax) of APDR curves, the pacing cycle length of inducing the APD alternans and the VAs were significantly increased (all P<0.05) in CHF group; the spatial dispersions of MAPD90, ERP and Smax of APDR curves in CHF group were also greater than in CTL group (all P<0.05). CONCLUSION: The ventricular APD alternans might be linked with occurrence of the VA in CHF rabbits. Increase of the Smax from APDR curves and the spatial dispersions of Smax in this CHF model might facilitate the development of ventricular arrhythmia.

[Impact of red cell distribution width on outcome of 16 681 patients with chronic systolic heart failure].

OBJECTIVE: To determinate the prognostic value of red cell distribution width (RDW) and the relationships between RDW and clinical characteristics in patients with chronic heart failure (CHF). METHODS: A total of 16 681 in-hospital patients with chronic systolic HF and LVEF < 50% from 12 hospitals in Hubei province, China were enrolled. All patients were followed up with telephone call. Patients were divided into RDW ≤ 13.2% (n = 3981), 13.3% - 14.1% (n = 3996), 14.2% - 14.8% (n = 4319) and ≥ 14.9% (n = 4385) groups. Multivariate Cox regression analysis was performed to determine whether RDW is an independent risk factor of all-cause mortality in overall patients, patients with various etiologies. Multivariate Cox proportional hazard analysis was performed to determine the risk of all-cause mortality among various RDW groups. RESULTS: (1) Compared with RDW ≤ 13.2% group, adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) of all-cause mortality for RDW 13.3% - 14.1%, 14.2% - 14.8% and ≥ 14.9% were 0.892 (95%CI 0.818 - 0.973, P = 0.01), 0.859 (95%CI 0.793 - 0.931, P < 0.01) and 1.034 (95%CI 0.961 - 1.111, P = 0.373) respectively. (2) Compared with MCV normal group, the adjusted HRs of MCV elevation and MCV decline groups were 1.351 (95%CI 1.063 - 1.718, P < 0.01) and 1.316 (95%CI 1.034 - 1.675, P < 0.01), respectively. (3) Compared to patients with rheumatic heart diseases, the adjusted HR for all-cause mortality in patients with coronary heart disease, dilated cardiomyopathy and hypertensive heart disease with RDW > 16% were 1.437 (95%CI 1.141 - 1.810, P < 0.01), 1.651 (95%CI 1.276 - 2.138, P < 0.01) and 1.276 (95%CI 1.004 - 1.621, P < 0.01), respectively. (4) The RDW is independently correlated with BMI (r = -0.345, P < 0.01), diastolic blood pressure (r = -0.321, P < 0.01), albumin (r = -0.411, P < 0.01), blood urine nitrogen (r = 0.476, P < 0.01), right ventricular end-diastolic diameter (r = 0.383, P < 0.01), LVEF (r = -0.463, P < 0.01) and heart rate (r = 0.379, P < 0.01). CONCLUSIONS: There is a J shape relationship between all-cause mortality and RDW. The elevation or decline of MCV with increased RDW is linked with increased all-cause mortality in CHF patients.

RA signaling pathway combined with Wnt signaling pathway regulates human-induced pluripotent stem cells (hiPSCs) differentiation to sinus node-like cells.

BACKGROUND: The source of SAN is debated among researchers. Many studies have shown that RA and Wnt signaling are involved in heart development. In this study, we investigated the role of retinoic acid (RA) and Wnt signaling in the induction of sinus node-like cells. METHODS: The experimental samples were divided into four groups: control group (CHIR = 0), CHIR = 3, RA + CHIR = 0 andRA + CHIR = 3. After 20 days of differentiation, Western blot, RT-qPCR, immunofluorescence and flow cytometry were performed to identify sinus node-like cells. Finally, whole-cell patch clamp technique was used to record pacing funny current and action potential (AP) in four groups. RESULTS: The best intervention method used in our experiment was RA = 0.25 µmol/L D5-D9 + CHIR = 3 µmol/L D5-D7. Results showed that CHIR can increase the expression of ISL-1 and TBX3, while RA mainly elevated Shox2. Immunofluorescence assay and flow cytometry further illustrated that combining RA with CHIR can induce sinus node-like cells (CTNT+Shox2+Nkx2.5-). Moreover, CHIR might reduce the frequency of cell beats, but in conjunction with RA could partly compensate for this side effect. Whole cell patch clamps were able to record funny current and the typical sinus node AP in the experimental group, which did not appear in the control group. CONCLUSIONS: Combining RA with Wnt signaling within a specific period can induce sinus node-like cells.

The mechanisms underlying ICa heterogeneity across murine left ventricle.

L-type calcium current (I(Ca)) plays a critical role in excitation-contraction coupling (ECC). Unlike transient outward K(+) current (I(to)), it is controversial whether I(Ca) transmural gradient exists in left ventricle. Although previous studies have shown some evidences for I(Ca) heterogeneity, the mechanism is still unknown. In this study, the authors recorded I(Ca) from epicardial (EPI) and endocardial (ENDO) myocytes isolated from murine left ventricle using patch-clamp technique. It was found that I(Ca) density was obviously larger in EPI than in ENDO (7.3 ± 0.3 pA/pF vs. 6.2 ± 0.2 pA/pF, at test potential of +10 mV, P < 0.05). The characteristics of I(Ca) showed no difference between these two regions except for the fast inactivation time constants (9.9 ± 0.9 ms in EPI vs. 13.5 ± 0.9 ms in ENDO, at test potential of +10 mV, P < 0.05). In addition, it was explored the molecular mechanism underlying I(Ca) transmural gradient by Western blot. The authors demonstrated that a higher activity of CaMKII in ENDO cells induced more nuclear translocation of p65, a component of nuclear factor-kappa B (NF-kB). Consequently, p65 in ENDO inhibited more transcription of Cav1.2, the main encoding gene for L-type calcium channels (LTCCs). These results reveal a difference in CaMKII/p65 signal pathway between EPI and ENDO that underlies this mechanism of I(Ca) heterogeneity in murine left ventricle.

[Prevalence and prognostic value of liver function abnormalities in patients with chronic systolic heart failure].

OBJECTIVE: To evaluate systemically the prevalence and prognostic values of liver function abnormalities in patients with chronic systolic heart failure (HF) have not been systematically evaluated. METHODS: A total of 16 681 hospitalized patients with a diagnosis of chronic systolic HF and left ventricular ejection fraction (LVEF) < 50% were recruited from 12 hospitals in Hubei Province. All patients were followed up by telephone contacts. And they were divided into the death and survival groups according to the follow-up results. RESULTS: Over a median follow-up period of 3 years, 6453 (38.69%) patients died. The prevalence of liver function abnormality was 71.94% (12 001/16 681). The elevations of direct bilirubin, γ-glutamyl-transferase and alanine aminotransferase were the most common findings accounting for 33.37% (4863/14 574), 32.51% (4337/13 341) and 30.12% (5024/16 681) respectively. The abnormality of alkaline phosphatase was rare and its increase and decrease accounted for 3.82% (474/12 397) and 4.51% (559/12 397) respectively. The prevalence of low albumin and total bilirubin elevation was 23.24% (3408/14 664) and 19.37% (3231/16 681). And high direct bilirubin (HR 1.264, 95%CI 1.103 - 1.423; P = 0.02), high total bilirubin (HR 1.126, 95%CI 1.019 - 1.234; P = 0.02) and low albumin (HR 0.889, 95%CI 0.794 - 0.889; P < 0.01) were determined as the independent risk factors of total mortality. There were the correlations of LVEF with direct bilirubin (r = -0.235, P < 0.01), total bilirubin (r = -0.209, P < 0.01), albumin (r = 0.107, P < 0.01) and right ventricular end-diastolic diameter (RVDD) with direct bilirubin (r = 0.149, P < 0.01), total bilirubin (r = 0.154, P < 0.01) and albumin (r = -0.086, P < 0.01). CONCLUSION: The prevalence of liver function abnormalities is high in patients with chronic systolic HF. Low albumin, high direct bilirubin and high total bilirubin increase their total mortalities. Low LVEF and high RVDD are positively correlated with a high prevalence of liver function abnormalities.

[Characteristics of in-hospital patients with chronic heart failure in Hubei province from 2000 to 2010].

OBJECTIVE: To evaluate the current status of chronic heart failure (CHF) in Hubei province and analyze the epidemiology of CHF including the general condition, etiology and pharmacological therapy. METHODS: Data of in-hospital patients with CHF were investigated between 2000 and 2010 from 12 hospitals in Hubei Province. INCLUSION CRITERIA: over 18 years of age, organic heart disease and with the symptom of HF including dyspnea and fatigue. Patients with a history of myocardial infarction in the prior 12 months, congenital heart disease, pericardial disease and the history of cancer were excluded. RESULTS: (1) A total of 12 450 patients were enrolled (7166 male, 57.56%). The average age was (62.0 ± 14.5) years. Patients in the scale of age ≥ 80, 70 - 79, 60 - 69, 50 - 59, 40 - 49 and < 40 was 9.53% (1187/12 450), 30.80% (3835/12 450), 23.45% (2920/12 450), 18.81% (2342/12 450), 10.73% (1336/12 450) and 6.67% (830/12 450), respectively (P < 0.01). The NYHA class I, II, III and IV was 0.60%, 23.20%, 50.31% and 26.50%, respectively. (2) The age of patients was significant reduced from 2000 - 2003, 2004 - 2006 to 2007 - 2010 [(66.4 ± 14.1) years, (64.9 ± 14.4) years and (64.2 ± 14.8) years, P < 0.01]. (3) The major causes of CHF were hypertension (31.54%), coronary heart disease (28.24%), dilated cardiomyopathy (26.57%) and rheumatic valvular heart disease (17.49%). The most frequent etiology for CHF was rheumatic valvular heart disease in patients aged less than 40 years old, dilated cardiomyopathy in patients aged 40 - 49 and 50 - 59 years and hypertension in patients aged 60-69, 70-79 and ≥ 80 years. (4) Drug use was as follows: Digitalis (47.49%), diuretics (68.75%), ACEI (50.66%), ß-blocker (44.06%) and aldosterone antagonist (53.08%). Use of digitalis (Wald χ(2) = 903.41, P < 0.01;r = 0.271, P < 0.01), diuretics (Wald χ(2) = 818.05, P < 0.01; r = 0.249, P < 0.01), aldosterone antagonists (Wald χ(2) = 76.92, P < 0.01; r = 0.091, P < 0.01) increased while the ß-blocker (Wald χ(2) = 160.65, P < 0.01; r = -0.117, P < 0.01) declined in proportion to NYHA class increase. CONCLUSIONS: The age of in-hospital patients with CHF declined in the previous 10 years. The primary etiology was hypertension for aged CHF in-hospital patients with CHF. There was big gap between guideline recommended standard therapy and current drug use for in-hospital patients with CHF in Hubei province.

Chinese Medicine Shensong Yangxin Capsule () Ameliorates Myocardial Microcirculation Dysfunction in Rabbits with Chronic Myocardial Infarction.

OBJECTIVE: To investigate the effect of Chinese compound Shensong Yangxin Capsule ( , SSYX) on myocardial microcirculation in myocardial-infarcted rabbits. METHODS: Myocardial infarction (MI) was established in rabbits by ligation of the left circumflex coronary. Thirty rabbits were randomly divided into the control group, the MI group (model), and the MI treated with SSYX group (MI+SSYX) by a random number table method. After 4 weeks of administration, low-energy real-time myocardial contrast echocardiography (RT-MCE) was conducted to assess the microcirculatory perfusion. Immunofluorescence double staining was used to detect the capillary density. The endothelial ultrastructure was observed with a transmission electron microscope. The mRNA expression levels of vascular endothelial growth factor (VEGF), endothelin 1 (ET-1), prostaglandin I2 (PGI2) and endothelial nitric oxide synthase (eNOS) were measured by real-time quantitative polymerase chain reaction (Real-time PCR). The plasmic levels of ET-1, thromboxane A2 (TXA2), nitric oxide (NO) and von willebrand factor (vWF) were examined with enzyme-linked immunosorbent assays (ELISA). RESULTS: SSYX significantly improved the myocardial blood volume, myocardial micro bubble velocity, and myocardial inflow according to the examination of RT-MCE, and it visibly ameliorated the capillary endothelial structure. Furthermore, compared with the MI group, the plasma levels of TXA2, ET-1 and vWF contents significantly decreased in the MI+SSYX group, and the ET-1 mRNA expression levels of myocardium in the border zone significantly decreased, and the VEGF, PGI2 and eNOS mRNA expression levels significantly increased (all P<0.05). CONCLUSIONS: SSYX has favorable advantages in ameliorating the impaired myocardial microcirculation following MI. The mechanisms of the effect are related to the ability of SSYX in balancing the endothelial-derived vasodilators and vasoconstrictors, and up-regulating the expression of VEGF and eNOS.

Abrogation of CC Chemokine Receptor 9 Ameliorates Ventricular Electrical Remodeling in Mice After Myocardial Infarction.

Introduction: Myocardial infarction (MI) triggers structural and electrical remodeling. CC chemokine receptor 9 (CCR9) mediates chemotaxis of inflammatory cells in MI. In our previous study, CCR9 knockout has been found to improve structural remodeling after MI. Here, we further investigate the potential influence of CCR9 on electrical remodeling following MI in order to explore potential new measures to improve the prognosis of MI. Methods and Results: Mice was used and divided into four groups: CCR9+/+/Sham, CCR9-/-/Sham, CCR9+/+/MI, CCR9-/-/MI. Animals were used at 1 week after MI surgery. Cardiomyocytes in the infracted border zone were acutely dissociated and the whole-cell patch clamp was used to record action potential duration (APD), L-type calcium current (I Ca,L ) and transient outward potassium current (I to ). Calcium transient and sarcoplasmic reticulum (SR) calcium content under stimulation of Caffeine were measured in isolated cardiomyocytes by confocal microscopy. Multielectrode array (MEA) was used to measure the conduction of the left ventricle. The western-blot was performed for the expression level of connexin 43. We observed prolonged APD90, increased I Ca,L and decreased I to following MI, while CCR9 knockout attenuated these changes (APD90: 50.57 ± 6.51 ms in CCR9-/-/MI vs. 76.53 ± 5.98 ms in CCR9+/+/MI, p < 0.05; I Ca,L : -13.15 ± 0.86 pA/pF in CCR9-/-/MI group vs. -17.05 ± 1.11 pA/pF in CCR9+/+/MI, p < 0.05; I to : 4.01 ± 0.17 pA/pF in CCR9-/-/MI group vs. 2.71 ± 0.16 pA/pF in CCR9+/+/MI, p < 0.05). The confocal microscopy results revealed CCR9 knockout reversed the calcium transient and calcium content reduction in sarcoplasmic reticulum following MI. MEA measurements showed improved conduction velocity in CCR9-/-/MI mice (290.1 ± 34.47 cm/s in CCR9-/-/MI group vs. 113.2 ± 14.4 cm/s in CCR9+/+/MI group, p < 0.05). Western-blot results suggested connexin 43 expression was lowered after MI while CCR9 knockout improved its expression. Conclusion: This study shows CCR9 knockout prevents the electrical remodeling by normalizing ion currents, the calcium homeostasis, and the gap junction to maintain APD and the conduction function. It suggests CCR9 is a promising therapeutic target for MI-induced arrhythmia, which warrants further investigation.