Corosolic acid attenuates cardiac ischemia/reperfusion injury through the PHB2/PINK1/parkin/mitophagy pathway.

Despite advances in treatment, myocardial infarction remains the leading cause of heart failure and death worldwide, and the restoration of coronary blood flow can also cause heart damage. In this study, we found that corosolic acid (CA), also known as plant insulin, significantly protects the heart from ischemia-reperfusion (I/R) injury. In addition, CA can inhibit oxidative stress and improve mitochondrial structure and function in cardiomyocytes. Subsequently, our study demonstrated that CA improved the expression of the mitophagy-related proteins Prohibitin 2 (PHB2), PTEN-induced putative kinase protein-1 (PINK1), and Parkin. Meanwhile, through molecular docking, we found an excellent binding between CA and PHB2 protein. Finally, the knockdown of PHB2 eliminated the protective effect of CA on hypoxia-reoxygenation in cardiomyocytes. Taken together, our study reveals that CA increases mitophagy in cardiomyocytes via the PHB2/PINK1/Parkin signaling pathway, inhibits oxidative stress response, and maintains mitochondrial function, thereby improving cardiac function after I/R.

Comprehensive view of macrophage autophagy and its application in cardiovascular diseases.

Cardiovascular diseases (CVDs) are the primary drivers of the growing public health epidemic and the leading cause of premature mortality and economic burden worldwide. With decades of research, CVDs have been proven to be associated with the dysregulation of the inflammatory response, with macrophages playing imperative roles in influencing the prognosis of CVDs. Autophagy is a conserved pathway that maintains cellular functions. Emerging evidence has revealed an intrinsic connection between autophagy and macrophage functions. This review focuses on the role and underlying mechanisms of autophagy-mediated regulation of macrophage plasticity in polarization, inflammasome activation, cytokine secretion, metabolism, phagocytosis, and the number of macrophages. In addition, autophagy has been shown to connect macrophages and heart cells. It is attributed to specific substrate degradation or signalling pathway activation by autophagy-related proteins. Referring to the latest reports, applications targeting macrophage autophagy have been discussed in CVDs, such as atherosclerosis, myocardial infarction, heart failure, and myocarditis. This review describes a novel approach for future CVD therapies.

The hippo kinases MST1/2 in cardiovascular and metabolic diseases: A promising therapeutic target option for pharmacotherapy.

Cardiovascular diseases (CVDs) and metabolic disorders are major components of noncommunicable diseases, causing an enormous health and economic burden worldwide. There are common risk factors and developmental mechanisms among them, indicating the far-reaching significance in exploring the corresponding therapeutic targets. MST1/2 kinases are well-established proapoptotic effectors that also bidirectionally regulate autophagic activity. Recent studies have demonstrated that MST1/2 influence the outcome of cardiovascular and metabolic diseases by regulating immune inflammation. In addition, drug development against them is in full swing. In this review, we mainly describe the roles and mechanisms of MST1/2 in apoptosis and autophagy in cardiovascular and metabolic events as well as emphasis on the existing evidence for their involvement in immune inflammation. Moreover, we summarize the latest progress of pharmacotherapy targeting MST1/2 and propose a new mode of drug combination therapy, which may be beneficial to seek more effective strategies to prevent and treat CVDs and metabolic disorders.

Comprehensive overview of Nrf2-related epigenetic regulations involved in ischemia-reperfusion injury.

Ischemic disease is a class of diseases in which an organ is ischemic due to vascular occlusion, a major contributor to death and disability worldwide. However, when the blood flow is restored, more severe damage occurs than ischemia alone and is known as ischemic-reperfusion injury (IRI). During reperfusion, the imbalance between the production of reactive oxygen species (ROS) and buffering capacity of the antioxidant defense system results in cell damage and death. Nuclear factor E2-related factor 2 (Nrf2) significantly affects antioxidant stress damage. The function of Nrf2 in the pathological process of IRI has been widely discussed, but the impact of epigenetic modifications associated with Nrf2 remains unclear. This article provides a comprehensive overview of the role and mechanism of Nrf2-related epigenetic modifications in the IRI of various organs, including the brain, heart, liver, and kidney. In addition, we summarize agonists that may target epigenetic regulation of Nrf2, which may be beneficial in seeking more effective strategies to improve IRI.

A novel monoclonal antibody against human B7-1 protects against chronic graft-vs.-host disease in a murine lupus nephritis model.

Lupus nephritis (LN) is the most common complication that causes mortality in patients with systemic lupus erythematosus. The B7-1/B7-2 and CD28/cytotoxic T-lymphocyte associated protein 4 co-stimulatory pathway serves a key role in autoimmune disease and organ transplantation. The aim of the present study was to generate and characterize a monoclonal antibody (mAb; clone 4E5) against human B7-1 and to investigate its potential use for the treatment of LN. The results demonstrated that the 4E5 mAb was successfully generated and able to recognize both human and mouse B7-1. After injection of this mAb into a mouse model with chronic graft-vs.-host disease (cGVHD)-induced lupus-like disease, the expression of CD21, CD23, CD80 and CD86 on B220+ B-cells in the spleen, and the concentrations of serum autoantibodies and urine protein, were decreased. Direct immunofluorescence analysis of the kidneys revealed that immunofluorescence of immune complex deposits was weaker in the 4E5-treated mice and electron microscopy analyses of renal tissues indicated that pathological injury of the kidneys of 4E5-treated mice was decreased compared with that in the model control mice. The results of the present study demonstrated that inhibition of the B7-1/CD28 co-stimulatory signaling pathway with the 4E5 mAb may represent a promising strategy to decelerate the progression of LN that is induced by cGVHD with potential for use in the treatment of other autoimmune diseases.

Association between Visceral Adiposity Index and hypertension among Chinese Adults: a nationwide cross-sectional study in the China Health and Nutrition Survey.

BACKGROUND: Visceral Adiposity Index (VAI) is an indicator of visceral adipose function. It showed an intense association with cardiometabolic risks, but it is unclear whether VAI is associated with hypertension. OBJECTIVE: We aim to determine the association of VAI with hypertension in Chinese adults. METHODS: We carried out a cross-sectional analysis of 5421 Chinese adults based on data which was from the China Health and Nutrition Survey (CHNS) 2009. Multivariable logistic regression and linear regression were performed to confirm the association. RESULTS: In multivariable logistic regression analysis, there was a dose-response association between VAI and the risk of incident hypertension (P for trend <0.01). The sex and age-adjusted odds ratios (ORs) [95% confidence interval (CI)] for the development of hypertension were 1.06 (0.90-1.26) in the second, 1.09 (0.92-1.29) in the third, and 1.28 (1.08-1.52) in the fourth VAI quartile, compared to the first quartile. The multivariable linear regression analysis indicated that VAI was positive association with systolic blood pressure (ß = 0.37; 95% CI, 0.13-0.62; P = 0.0028) and diastolic blood pressure (ß = 0.26; 95% CI, 0.12-0.40; P = 0.0004). The subgroup analysis showed that VAI had more positive association with hypertension in participants with an apolipoprotein A1 of ≥1.2 g/L (P = 0.0115) or a hemoglobin A1c of ≥6.5% (P = 0.0369). CONCLUSIONS: VAI was positively associated with hypertension among the Chinese adult population, and it may assume an indicator of hypertension risk for the Chinese population.

Regulation mechanism of aquaporin 9 gene on inflammatory response and cardiac function in rats with myocardial infarction through extracellular signal-regulated kinase1/2 pathway.

The aim of this study was to investigate the regulation mechanism of aquaporin 9 (AQP9) gene on inflammatory response and cardiac function in rats with myocardial infarction (MI) through extracellular signal-regulated kinase1/2 (ERK1/2) pathway. The constructed rats models of MI were randomly divided into 6 groups: control group (sham operation group, MI modeling sham operation), model group (MI modeling), NC group (MI modeling, tail vein injection of AQP9 negative control sequence vector), AQP9 shRNA group (MI modeling, tail vein injection of AQP9 shRNA plasmid vector), U0126 group (MI modeling, tail vein injection of ERK signaling pathway inhibitor), and AQP9 shRNA + U0126 group. The hemodynamics and cardiac function of rats in each group were detected on the seventh day of modeling. The levels of AQP9 and inflammatory factors [tumour necrosis factor-α (TNF-α), interleukin-6 (IL-6), interleukin-10 (IL-10)] in peripheral blood of rats were detected by ELISA method. qRT-PCR and western blot were used to detect the mRNA and protein expression of AQP9, ERK1/2, B-cell lymphoma-2 (Bcl-2), Bcl-associated x (Bax) in the myocardial tissue of rats. TTC and TUNEL staining were used to observe myocardial infarct size and apoptosis of myocardial cells in each group. Compared with control group, the levels of heart rate, left ventricular end-diastolic pressure, TNF-α, and IL-6 were increased in each group of rats with MI (all p < 0.05), while the levels of systolic blood pressure, diastolic blood pressure, mean arterial pressure, left ventricular systolic pressure, and IL-10 were significantly decreased (all p < 0.05). The mRNA and protein expression levels of AQP9, ERK1/2 phosphorylation and Bax were significantly increased, as well as the myocardial infarct size, apoptosis index of myocardial tissue (all p < 0.05), the mRNA and protein expression levels of Bcl-2 were significantly decreased (all p < 0.05). The AQP9 gene knock-down or exogenous administration of the ERK1/2 inhibitor U0126 could improve the above indexes. However, the combination of AQP9 gene knock-down and U0126 showed no further effect. Silencing AQP9 gene can inhibit the activation of ERK1/2 signaling pathway, attenuate the inflammatory response in rats with MI, inhibit apoptosis of myocardial cells, and improve cardiac function.

The effect of dabigatran on thrombin generation and coagulation assays in rabbit and human plasma.

OBJECTIVES: Dabigatran etexilate is widely used for stroke prevention in the patients with atrial fibrillation. The anticoagulation activity of dabigatran is not necessary monitored in routine clinical practice. We aimed to study the effect of dabigatran on thrombin generation (TG) and coagulation assays in rabbit and human plasma. METHODS: Rabbits received different concentrations of dabigatran etexilate (5 mg/kg, 10 mg/kg). Patients with atrial fibrillation took 110 mg dabigatran etexilate twice daily. The concentrations of dabigatran in rabbit and human plasma were detected by liquid chromatography/tandem mass spectrometry (LC-MS/MS) and ecarin chromogenic assay (ECA). The relationship between plasma dabigatran concentrations and the activated partial thromboplastin time (aPTT), prothrombin time (PT), thrombin time (TT), and TG were evaluated. RESULTS: There was strong correlation between LC-MS/MS and ECA (P < 0.001). Bland Altman analysis demonstrated that ECA assay could accurately predict human plasma dabigatran concentrations whereas underestimate the plasma concentrations of dabigatran in rabbits. Both the PT and the aPTT assays showed low correlations with dabigatran. The TT assay was highly sensitive to dabigatran levels. Low concentrations of dabigatran paradoxically increased TG. CONCLUSIONS: LC-MS/MS is the gold standard for detecting the concentrations of dabigatran. ECA correlates well with LC-MS/MS. The coagulation assays depend more on other factors. Paradoxical enhancement of TG may predict clinically rebound hypercoagulability and warrants further exploration.

A monoclonal antibody against CD86 and its protection in a murine lupus nephritis model of chronic graft-versus-host disease.

CONTEXT: Lupus nephritis is the most common complication that causes the death of systemic lupus erythematosus patients. CD28/CTLA4 and their ligands CD80 or CD86 costimulatory pathway play a pivotal role in autoimmune disease and organ transplantation. OBJECTIVES: We generated a monoclonal antibody (clone 1D1) against human CD86 (1D1) that could recognize both human and mouse CD86, and blocked the CD86/CD28 costimulatory pathway with our mAb on a murine lupus nephritis model induced with chronic graft-versus-host disease (cGVHD). MATERIALS AND METHODS: Experimental lupus nephritis mice were induced with cGVHD, and splenocyte population were analyzed by flow cytometry. Autoantibodies and proteinuria were detected to evaluate the severity of lupus nephritis. The change of histopathology was observed by microscopy, fluorescence microscopy and electron microscopy. RESULTS: we successfully generated a monoclonal antibody against human CD86(1D1). 1D1 mAb could recognize not only human CD86, but also mouse CD86. 1D1 was applied to the cGVHD-induced experimental lupus nephritis model, and our study found the production of ANA and anti-dsDNA in the 1D1-treated group was lower than those in IgG-treated group after four weeks. The pathological injure of kidney in the 1D1-treated group was lighten than that in IgG-treated group. DISCUSSION AND CONCLUSIONS: Our data showed that blockade of CD86/CD28 with 1D1 induced a significant remission of proteinuria, production of autoantibodies, immune complex deposition and renal parenchyma lesions in experimental mice. Anti-CD86 Abs might be a potential method for immune therapy in autoimmune diseases and transplantation.

[Inhibition effects of wood vinegar on Alternaria panax and Botrytis cinerea].

OBJECTIVE: Less fungicides could be used to biocontrol Alternaria panax and Botrytis cinerea, this experiment can offer preliminary theory for wood vinegar as a botanic fungicide. METHODS: The in vitro inhibition activities of wood vinegar on Alternaria panax and Botrytis cinerea were tested by using mycelial growth rate method and spore germination method. RESULTS: Inhibition of mycelium growth rate to Alternaria panax was 100% when the concentration of wood vinegar was no less than 3.0%, while the inhibition of mycelium growth rate and spore germination rate were 70.68% and 84.47%, respectively, at concentration of wood vinegar 2.25%. Inhibition of mycelium growth rate and spore germination rate to Botrytis cinerea were 100% when the concentration of wood vinegar was no less than 2.25%. CONCLUSION: Wood vinegar concentration of no less than 2.25% can be used as a biocontrol agent of Alternaria panax and Botrytis cinerea, it is useful for the further field trial.

Simvastatin activates the PPARγ-dependent pathway to prevent left ventricular hypertrophy associated with inhibition of RhoA signaling.

Left ventricular hypertrophy is an independent risk factor for major adverse cardiovascular events. Statins have positive effects on this condition; however, the mechanisms are incompletely understood. In this study, we examined whether the effect of simvastatin on left ventricular hypertrophy can be mediated with the peroxisome proliferator-activated receptor (PPAR)γ-dependent pathway in rabbits with nonischemic heart failure (HF). We induced aortic insufficiency and constriction in 48 rabbits and divided them equally into control, HF, and HF with simvastatin therapy (HF-SIM) groups. The HF-SIM group was given 10 mg/kg/d of simvastatin. We echocardiographically measured baseline and 8-week cardiac structure and function, and we used Western blot, polymerase chain reaction, and electrophoretic analytic techniques to evaluate messenger RNA expression and protein expression and activity. In comparison with the HF group, the HF-SIM rabbits had an increased ejection fraction and decreased left ventricular mass index, interventricular septal thickness, ventricular posterior-wall thickness, and collagen volume fraction. Moreover, the messenger RNA and protein expression of PPARγ in the HF-SIM rabbits were significantly higher than those in the HF rabbits; and the activity and expression of nuclear factor-κB subunit p65, RhoA, and Rho GTPase were significantly lower. Our results indicate that simvastatin therapy attenuates the PPARγ-dependent pathway in association with the inhibition of RhoA and Rho GTPase signaling to inhibit nuclear factor-κB activation, thus preventing the development of left ventricular hypertrophy and fibrosis in rabbits with nonischemic heart failure.

Effects of enalapril on the expression of cardiac angiotensin-converting enzyme and angiotensin-converting enzyme 2 in spontaneously hypertensive rats.

BACKGROUND: The discovery of angiotensin-converting enzyme 2 (ACE2) has greatly modified understanding of the renin-angiotensin system (RAS). AIMS: To investigate the cardiac expression of ACE2 and ACE in spontaneously hypertensive rats (SHRs) and the effects of enalapril on them. METHODS: Fifteen SHRs were randomly assigned to two groups: an SHR control group (n=7), treated with vehicle; and an enalapril group (n=8), treated with enalapril (15 mg/kg/day). After 4 weeks of treatment, the rats were killed and the left ventricular tissue was dissected. Reverse transcription-polymerase chain reaction and Western blot protein staining were performed to detect expression of ACE2 and ACE messenger ribonucleic acid (mRNA) and protein. Ten Wistar Kyoto rats (WKYs) served as the normotensive control group, which were treated with vehicle. RESULTS: Compared with in normotensive WKYs, cardiac expression of ACE mRNA and protein in SHRs was increased (1.68±0.34 vs. 0.33±0.12, P<0.05 and 1.21±0.14 vs. 0.71±0.11, P<0.05, respectively), whereas cardiac expression of ACE2 mRNA and protein was decreased (0.50±0.15 vs. 1.16±0.24, P<0.05 and 0.71±0.24 vs. 1.22±0.14, P<0.05, respectively). After treatment with enalapril, the levels of ACE mRNA and protein were decreased (0.44±0.19 vs. 1.68±0.34, P<0.01 and 0.87±0.13 vs. 1.21±0.14, P<0.05, respectively), the level of ACE2 mRNA was increased (1.77±0.49 vs. 0.50±0.15, P<0.05) but the level of ACE2 protein remained unchanged. CONCLUSIONS: In SHRs, the expression of cardiac ACE was remarkably increased, whereas ACE2 was notably decreased. Reduction of ACE and elevation of ACE2 might be one of the mechanisms underlying the antihypertensive function of enalapril.

[Gene cloning, expression and binding activity of anti-CD86 scFv].

OBJECTIVE: To construct and express the single chain variable fragment (scFv) against human CD86 in CHO cells, and observe its biological functions of binding with antigen. METHODS: The V(H); and V(L); genes were cloned by RT-PCR from a murine hybridoma cell line 1D1, which produced the monoclonal antibody (mAb) against human CD86. The CD86-scFv gene was integrated into eukaryotic expression vector to construct pIREST2-EGFP/scFv. CHO cells were transfected by pIREST2-EGFP/scFv plasmid with Lipofectamine(TM); 2000 and then were selected by G418. We used IMAC affinity chromatography to purify CD86-scFv and quantified its concentration by BCA method. Then the identification of CD86-scFv binding to membrane CD86 was performed through competitive inhibition assay. In addition, the growth inhibition effect of CD86-scFv on Raji cells was detected via MTT assay. RESULTS: One cell line stably expressing CD86-scFv was obtained. The CD86-scFv could identify CD86 molecules on L929-CD86, Raji and Daudi cells, and the positive rates were 67.0%, 72.3% and 80.5%, respectively. CD86-scFv showed the competitive binding to murine parent antibody 1D1. Moreover, CD86-scFv inhibited the growth of Raji cells and the inhibition rate was 28.3% 72 h after 20 µg/mL CD86-scFv was added into Raji cells. CONCLUSION: CD86-scFv has been successfully expressed in CHO cells (named SA-IV) and the antibody shows a good biological function of recognizing CD86 and inhibiting the growth of Raji cells.

Activation of autophagy in ischemic postconditioning contributes to cardioprotective effects against ischemia/reperfusion injury in rat hearts.

We tested the hypothesis that ischemic postconditioning (IPost) induces autophagy and the activation of autophagy contributes to the cardioprotective effects against ischemia/reperfusion injury in rat hearts. Rats were subjected to IPost established by 3 cycles of 10-second reperfusion followed by 10-second ischemia at the end of 30-minute ischemia. The activation of autophagy was assessed by the morphological and biochemical examinations after 120-minute reperfusion in ventricular tissue. To investigate the contribution of autophagy to IPost, the rats were pretreated with the autophagy inhibitor 3-methyl-adenine (3-MA). We found that IPost increased the formation of autophagic vacuoles, the autophagic-related protein levels of LC3-II, Beclin1, lysosome-associated membrane protein 2, and cathepsin D, and the mRNA level of LC3 and Beclin1 in the risk zone of the postconditioned hearts. Furthermore, 3-MA treatment significantly reversed the reduction effect of IPost on infarct volume, and in the meantime, inhibited the induction of LC3 and Beclin1. In addition, 3-MA treatment inhibited the antiapoptotic-related protein levels of Bcl-2 and increased the apoptotic-related protein levels of Bad. Taken together, these results indicate that the protective effects of IPost are associated with the activation of autophagy in rat hearts.

[Expression and antigen binding activity of anti-human CD86 diabody].

AIM: To construct a recombinant eukaryotic expression vector of anti-human CD86 diabody gene and express anti-CD86 diabody through Chinese hamster ovary (CHO) cells, then analyze the capability of the diabody to recognize the tumor cells expressing CD86 and its biological effect. METHODS: The antibody heavy and light chain viable region gene (V(H); and V(L);) were cloned from hybridoma cell 1D1 which secreted anti-human CD86 monoclonal antibody. Anti-human CD86 diabody gene V(H);-(GGGGS)-V(L); was constructed by SOE-PCR. Then we inserted it into eukaryotic expression vector to construct a recombinant vector pIRES2-EGFP/CD86-diabody. The recombinant vector was transfected into CHO cells with Lipofectamine(TM); 2000, and the cell clones secreting CD86 diabody were screened by G418. We used IMAC to purify CD86 diabody and quantified its concentration by BCA method. The capability of the diabody to recognize the CD86 expressed on Raji and Daudi was analyzed through flow cytometry. After Raji cells were treated with CD86 diabody for 72 h, its proliferation inhibiting effect was investigated by MTT assay. RESULTS: We have obtained one CHO cell line that stably secreted CD86 diabody. The concentration of CD86 diabody after purification was 5.24 mg/L. The positive rates of CD86 diabody to recognize Raji and Daudi were 77.2% and 70.6%, respectively. After CD86 diabody treatment for 72 h, the inhibition rate of Raji cells was 37%. CONCLUSION: The anti-human CD86 diabody which we obtained successfully could recognize CD86 expressed on tumor cells specifically, and inhibit the proliferation of these tumor cells effectively.

[Effect of CD80-scFv on recognition of CD80 molecule and proliferation of different tumor cells in vitro].

AIM: To prepare CD80-scFv in CHO cells and investigate its effect on the recognition and proliferation of different tumor cells. METHODS: The CD80-scFv was purified from culture supernatant without fetal calf serum (FCS) by IMAC affinity chromatography, and then bound to CD80 molecule on the Daudi, U251, A375 and 8266 cells detected by flow cytometry. Different concentrations of CD80-scFv were added in the training system of different tumor cells, and we analyzed the influence on the proliferation of these cells by MTT assay. With 8266 cells which expressed CD80 highly and were treated by mitomycin firstly as the APC, and human PBMC as the effect cells, we analyzed the influence of the CD80-scFv on the proliferation of PBMC by blocking the co-stimulatory signal. RESULTS: The concentration of CD80-scFv purified from FCS was about 6.67 mg/L and the binding rate of CD80-scFv with Daudi, U251, A375, 8266 and U266 were 96.8%, 39.6%, 20.5%, 99.9% and 3.8%, respectively. CD80-scFv suppressed the proliferation of Daudi and 8266 cells which expressed CD80 highly, and the inhibition rate of Daudi and 8266 cells cultured with CD80-scFv (the final concentration was 25 µg/mL) was 24.04% and 24.16%, respectively. Additionally, the antibody suppressed the proliferation of PBMC by blocking the co-stimulatory signal mediated by CD80-CD28. CONCLUSION: CD80-scFv can recognize CD80 molecule and suppress the proliferation of tumor cells which express CD80 highly.

WITHDRAWN: Simvastatin prevents decreased SERCA2a activity in non-ischemic heart failure in rabbits via inhibition of ß-adrenergic signaling.

The Publisher regrets that this article is an accidental duplication of an article that has already been published, http://dx.doi.org/10.1016/j.biomag.2010.09.003. The duplicate article has therefore been withdrawn.

[Effects of valsartan on myocardial calcium/calmodulin-dependent protein kinase-II expression and activity in a rabbit model of heart failure].

OBJECTIVE: To investigate the effects of valsartan on myocardial expression and activity of calcium/calmodulin-dependent protein kinase-II (CaMK II) in a rabbit model of heart failure. METHODS: Rabbits were divided into sham-operated group, heart failure group (volume overload by aortic valve destruction induced aortic insufficiency plus pressure overload induced by abdominal aortic banding) and heart failure plus valsartan (20 mg x kg(-1) x d(-1), n = 9 each). Seven weeks later, echocardiography and hemodynamic examinations were performed and myocardial CaMK II expression and activity were detected by Western blot and CaMK II activity assay kit, respectively. RESULTS: Compared with the sham operated rabbits, left ventricular mass index [LVMI (3.61 +/- 0.09) g/kg vs. (1.32 +/- 0.06) g/kg, P<0.05] and end-diastolic pressure [LVEDP (23.00 +/- 2.37) mm Hg (1 mm Hg = 0.133 kPa) vs. (-1.50 +/- 0.5) mm Hg, P<0.05] were significantly increased while left ventricular shortening fractions [LVFS (17.38 +/- 3.13)% vs. (37.83 +/- 3.58)%, P<0.05] and ejection fraction [LVEF (38.50 +/- 6.07)% vs. (71.92 +/- 4. 56)%, P<0.05] were significantly decreased (all P<0.05) in heart failure rabbits, these changes could be significantly attenuated by valsartan treatment: LVMI [(2.07 +/- 0.14) g/kg vs. (3.61 +/- 0.09) g/kg, P<0.05], LVEDP [(2.17 +/- 0.72) mm Hg vs. (23.00 +/- 2.37) mm Hg, P<0.05], LVFS [(33.83 +/- 2.85)% vs. (17.38 +/- 3.13)%, P<0.05] and LVEF [(64.45 +/- 3.66)% vs. (38.50 +/- 6.07)%, P<0.05]. CaMK II expression (1.45 +/- 0.13 vs 0.89 +/- 0.05, 1.13 +/- 0.12, P<0.05) and activity [(3.54 +/- 0.17) pmol x min(-1) x microg(-1) vs. (2.18 +/- 0.13) pmol x min(-1) x microg(-1), (2.79 +/- 0.14) pmol x min(-1) x microg(-1), P<0.05] in heart failure rabbits were significantly increased than those sham operated rabbits which could be significantly attenuated by valsartan treatment. CONCLUSION: Valsartan improved cardiac function in heart failure rabbits probably via downregulating myocardial CaMK II expression and activity.

[The changes of funny currents in the ventricular myocytes of neonatal rats and adult rats].

AIM: To record funny currents (If) of ventricular myocytes and to analysize hyperpolarization-activated cation channel(HCN) expression in the rats of different ages. METHODS: Fresh ventricular myocytes were isolated from 3 days rats and adult rats.HCN expressions were measured by real-time quantitative polymerase chain reaction(real-time PCR). It was recorded through whole-cell patch clamp. RESULTS: HCN1, HCN2, HCN3, HCN4 mRNA represented 0.23% +/- 0.01%, 83.58% +/- 0.04%, 0.79% +/- 0.01%, 15.44% +/- 0.01% of total HCN mRNA in the neonatal rats, respectively. If was recorded and the threshold for activation was -75 mV. In the adult rat, HCN1, HCN2, HCN3, HCN4 mRNA represented 0.72% +/- 0.02%, 91.58% +/- 0.08%, 0.27% +/- 0.02%, 7.12% +/- 0.02% of total HCN mRNA. The ratio of HCN2 to HCN4 was approximately (13.06 +/- 0.21):1. The threshold for activation of If was approximately -115 mV in the adult rats. CONCLUSION: With the development of rats, the value of If is smaller. The threshold for activation of If is more negative. The ratio of HCN2 to HCN4 is bigger.

[Effects of amiodarone on funny current I(f) channel gene expression in neonatal rat ventricular myocytes].

OBJECTIVE: To analysis the effect of amiodarone on funny current (I(f)) and hyperpolarization-activated cation channel (HCN) gene expressions of the neonatal rat ventricular myocytes. METHODS: Ventricular myocytes of 1 - 3 days-old rats were isolated and cultured. The cardiomyocytes were treated by amiodarone (0.01, 0.1, 1, 10, 100 micromol/L) for 3 hours or amiodaron (10 micromol/L) for 0, 0.5, 1, 3, 6 hours. The I(f) and HCN 1 - 4 gene expressions were measured through the whole-cell configuration of the patch-clamp technique and real-time quantitative polymerase chain reaction (real-time PCR) using SYBR Green PCR kit. RESULTS: (1) HCN1, HCN2, HCN3 and HCN4 represented (0.23 +/- 0.01)%, (83.58 +/- 0.04)%, (0.79 +/- 0.01)% and (15.44 +/- 0.01)% of total HCN mRNA, respectively. (2) Amiodaron resulted in a dose-dependent I(f) [(3.1 +/- 0.9)%, (9.7 +/- 2.4)%, (36.7 +/- 5.8)%, (80.3 +/- 1.8)% and (85.9 +/- 3.1)%, respectively at -145 mV, IC(50) (1.32 +/- 0.28) micromol/L], HCN2 [(2.1 +/- 0.8)%, (8.9 +/- 3.6)%, (30.1 +/- 4.2)%, (78.3 +/- 3.6)% and (81.1 +/- 1.9)%, respectively] and HCN4 decrease [(0.5 +/- 0.2)%, (2.1 +/- 2.6)%, (8.8 +/- 3.2)%, (60.1 +/- 4.6)% and (59.6 +/- 6.5)%, respectively]. (3) Amiodaron (10 micromol/L) also induced a time-dependent I(f) [(1.1 +/- 0.1)%, (12.6 +/- 2.3)%, (80.6 +/- 2.2)% and (80.1 +/- 2.1)%, respectively], HCN2 [(1.0 +/- 0.1)%, (9.8 +/- 3.9)%, (82.9 +/- 4.6)% and (83.9 +/- 1.7)%, respectively] and HCN4 decrease [(0.1 +/- 0.1)%, (1.9 +/- 1.1)%, (59.4 +/- 7.8)% and (60.9 +/- 3.1)%, respectively]. However, HCN1 and HCN3 expressions were not affected by amiodaron treatment. CONCLUSION: Current density of I(f) and the expression of HCN2 and HCN4 were decreased by amiodaron which might be the possible antiarrhythmic working mechanisms of amiodaron.