Kaempferol ameliorates in-vitro and in-vivo postovulatory oocyte ageing in mice.

RESEARCH QUESTION: Does kaempferol alleviate postovulatory oocyte ageing, thereby maintaining their early embryonic development capacity? DESIGN: The effects of kaempferol on postovulatory ageing were investigated in vitro and in vivo by short-term kaempferol administration (mature oocytes were cultured in a kaempferol-containing medium for 12 h; mice were intragastrically administered with the appropriate amount of kaempferol for 21 days). Spindle morphology and chromosome alignment, levels of oxidative stress and the gap junction were assessed by immunofluorescence. Fertilization ability and early embryonic development ability of each oocyte group was detected by IVF. Fertilization of the ageing oocyte model was used to explore whether kaempferol could improve adverse pregnancy outcome. RNA-sequencing and quantitative polymerase chain reaction were used to identify the cellular pathways through which kaempferol relieves postovulatory oocyte ageing in vivo. RESULTS: Kaempferol administration altered various processes in the ageing oocytes, including oxidative stress, the peroxisome, TNF signalling, cAMP signalling and the gap junction pathway. Expression of several important genes, such as Sirt1, Mapk1, Ampk and Foxo3, was regulated. Moreover, kaempferol ameliorated adverse pregnancy outcomes of fertilized ageing oocytes. IVF results indicate that kaempferol could partially counteract the effects of oocyte ageing on fertilization capacity (pronucleus: kaempferol, 69.08 ± 2.37% versus aged, 38.95 ± 3.58%) and early embryonic development (blastocyst: kaempferol, 50.02 ± 3.34% versus aged, 30.83 ± 5.46%). CONCLUSIONS: Our results indicate that kaempferol may be a potent natural antioxidant, have implications for animal husbandry and may help improve the success rate of IVF and ICSI. Further clinical trials are needed.

Wnt11 preserves mitochondrial membrane potential and protects cardiomyocytes against hypoxia through paracrine signaling.

We investigated the effect of Wnt11 on mitochondrial membrane integrity in cardiomyocytes (CMs) and the underlying mechanism of Wnt11-mediated CM protection against hypoxic injury. A rat mesenchymal stem cell (MSC) line that overexpresses Wnt11 (MSCWnt11 ) and a control cell line transduced with empty vector (MSCNull ) were established to determine the cardioprotective role of Wnt11 in response to hypoxia. Mitochondrial membrane integrity in MSCWnt11 cells was assessed using fluorescence assays. The role of paracrine signaling mediated by vascular endothelial growth factor (VEGF), basic fibroblast growth factor (b-FGF), and insulin-like growth factor 1 (IGF-1) in protecting CMs against hypoxia were investigated using cocultures of primary CMs from neonatal rats with conditioned medium (CdM) from MSCWnt11 . MSCWnt11 cells exposed to hypoxia reduced lactate dehydrogenase release from CMs and increased CM survival under hypoxia. In addition, CMs cocultured with CdM that were exposed to hypoxia showed reduced CM apoptosis and necrosis. There was significantly higher VEGF and IGF-1 release in the MSCWnt11 group compared with the MSCNull group, and the addition of anti-VEGF and anti-IGF-1 antibodies inhibited secretion. Moreover, mitochondrial membrane integrity was maintained in the MSCWnt11 cell line. In conclusion, overexpression of Wnt11 in MSCs promotes IGF-1 and VEGF release, thereby protecting CMs against hypoxia.

Comparison of the Effects of Ticagrelor and Clopidogrel on Inflammatory Factors, Vascular Endothelium Functions and Short-Term Prognosis in Patients with Acute ST-Segment Elevation Myocardial Infarction Undergoing Emergency Percutaneous Coronary Intervention: a Pilot Study.

BACKGROUND/AIMS: Acute ST-segment elevation of myocardial infarction (STEMI) is the most severe type of acute coronary syndrome (ACS). Particular attention has been focused on studying the pathogenesis of STEMI, and how to prevent thrombosis, reduce inflammatory reaction, stabilize plaques and improve vascular endothelial functions to preserve the survived myocardium. This study aimed to compare the anti-inflammatory endothelium-protective effects, clinical prognosis, and relevant bleeding risks of ticagrelor versus clopidogrel in patients with STEMI who underwent urgent percutaneous coronary intervention (PCI) and provide certain experimental evidence and a theoretical basis for the selection of safe and effective drugs and their proper dosage, thereby further guiding clinical medication. METHODS: We sequentially enrolled 193 patients (104 males and 89 females) admitted to hospital due to acute STEMI. These patients underwent urgent PCI between December 2013 and May 2015 and met the inclusion criteria. They were assigned (1: 1) into two groups according to different treatments, 97 patients in the ticagrelor group (treatment group), and 96 patients in the clopidogrel group (control group). Levels of hypersensitive C-reactive protein (hs-CRP), interleukin-6 (IL-6), and endothelial cell-specific molecule 1 (ESM-1) taken at admission and 24 h, 4 days, and 7 days after administration, as well as the correlation between the levels of IL-6, hs-CRP, and ESM-1, were determined in the two groups. At the same time, the effects of treatment with ticagrelor and clopidogrel on the efficacy endpoint events (ischemic and safety) were explored. RESULTS: No statistically significant difference was found in the levels of hs-CRP, IL-6, or ESM-1 at admission between the two groups (P> 0.05); Their levels were significantly elevated 24 h after administration, with statistical differences between two groups (P< 0.05). Furthermore, a downward trend with statistically significant differences was found on Day 4 and Day 7 (P< 0.05); ESM-1 levels increased along with increases of hs-CRP and IL-6 levels, indicating ESM-1 was positively correlated with hs-CRP (r=0.523, P< 0.001) and IL-6 (r=0.431, P< 0.001); and the occurrence rates of ischemic endpoint events at 30 days were lower in the treatment group than in the control group. The occurrence of safety endpoint events was higher than in the control group; however, no statistically significant difference was found (P> 0.05). CONCLUSIONS: Compared with clopidogrel, ticagrelor appears to rapidly reduce the prevalence of inflammatory reactions and stabilize the functions of vascular endothelium to improve the stability of atherosclerotic plaque and decrease the occurrence rate of thrombosis as well as ischemic outcome events without any obvious increase in the risk of bleeding in patients with acute STEMI receiving urgent PCI. This renders it a potential drug for clinical practice. At the same time, measurement of ESM-1, a new biological marker for vascular endothelial function disorder, could possibly become a simple, effective, and practical new method for clinical evaluation of risk stratification of patients with acute STEMI at admission.

Baicalin protects H9c2 cardiomyocytes against hypoxia/reoxygenation-induced apoptosis and oxidative stress through activation of mitochondrial aldehyde dehydrogenase 2.

Baicalin, a flavonoid glycoside separated from Scutellaria baicalensis, has cardioprotection against ischaemia/reperfusion (I/R) injury. Mitochondrial aldehyde dehydrogenase 2 (ALDH2) is considered as an endogenous protective mechanism against I/R injury depending on its anti-oxidant and anti-apoptotic characteristics. The present study demonstrates whether ALDH2 contributes to the cardioprotection of baicalin against hypoxia/reoxygenation (H/R)-inudced H9c2 cardiomyocytes injury. Our results observed that H/R treatment resulted in a significant decrease in cells viability and obvious increases in caspase-3 activity and apoptosis rate in H9c2 cells, while these alterations were evidently reversed by baicalin pretreatment. Simultaneously, baicalin mitigated H/R-induced the decreases in the levels of ALDH2 mRNA and protein as well as the activity of ALDH2 in H9c2 cells. However, we found that daidzin, an ALDH2 antagonist, remarkably attenuated baicalin-elicited inhibitory action on H/R-induced the downregulation of cells viability and Bcl-2 protein expression, and the upregulations of caspase-3 activity, apoptosis rate, cytochrome c and Bax proteins expressions in H9c2 cells. In addition, baicalin reversed H/R-induced oxidative stress as evidenced by the downregulation of malondialdehyde (MAD) and 4-hydroxy aldehydes (4-HNE) levels, the inhibition of endogenous reactive oxygen species (ROS) generation, and the downregulation of superoxide dismutase (SOD) activity induced by H/R treatment, while these effects were also blocked by daidzin. Furthermore, we found that Alda-1, an ALDH2 agonist, also abolished H/R-induced cytotoxicity, apoptosis, and oxidative stress, indicating that ALDH2 mediated H/R-induced H9c2 cell injury. Overall, these results suggested that baicalin prevents H/R-induced apoptosis and oxidative stress through enhancing ALDH activity and expression in H9c2 cardiomyocytes.

Ischemia triggered ATP release through Pannexin-1 channel by myocardial cells activates sympathetic fibers.

The cardiovascular system is extensively innervated by the autonomic nervous system, and the autonomic modulation including sympathetic innervation is crucial to the function of heart during normal and ischemic conditions. Severe myocardial ischemia could cause acute myocardial infarction, which is one of the leading diseases in the world. Thus studying the sympathetic modulation during ischemia could reduce the probability of myocardial infarction and further heart failure. The neurotransmitter ATP is released by myocardial cells during ischemia; however, the effect of ATP release remains elusive. We examined whether ATP released during ischemia functions as a neurotransmitter that activates sympathetic nerve in the heart. A novel technique of recording the sympathetic fiber calcium imaging in mouse cardiac tissue slices was used. We have applied the Cre/loxP system to specifically express GCaMP3, a genetically encoded calcium indicator, in the sympathetic nerve. Using this technique, we found that ATP released by myocardial cells through Pannexin-1 channel during ischemia could evoke calcium responses in cardiac sympathetic nerve fibers. Our study provides a new approach to study the cell and nerve interaction in the cardiac system, as well as a new understanding of ATP function during ischemia.

GATA-4 induces changes in electrophysiological properties of rat mesenchymal stem cells.

BACKGROUND: Transplanted mesenchymal stem cells (MSC) can differentiate into cardiac cells that have the potential to contribute to heart repair following ischemic injury. Overexpression of GATA-4 can significantly increase differentiation of MSC into cardiomyocytes (CM). However, the specific impact of GATA-4 overexpression on the electrophysiological properties of MSC-derived CM has not been well documented. METHODS: Adult rat bone marrow MSC were retrovirally transduced with GATA-4 (MSC(GATA-4)) and GFP (MSC(Null)) and subsequently co-cultured with neonatal rat ventricular cardiomyocytes (CM). Electrophysiological properties and mRNA levels of ion channels were assessed in MSC using patch-clamp technology and real-time PCR. RESULTS: MSC(GATA-4) exhibited higher levels of the TTX-sensitive Na(+) current (INa.TTX), L-type calcium current (ICa.L), transient outward K(+) current (Ito), delayed rectifier K(+) current (IKDR) and inwardly rectifying K(+) current (IK1) channel activities reflective of electrophysiological characteristics of CM. Real-time PCR analyses showed that MSC(GATA-4) exhibited upregulated mRNA levels of Kv1.2, Kv2.1, SCN2a1, CCHL2a, KV1.4 and Kir1.1 channels versus MSC(Null). Interestingly, MSC(GATA-4) treated with IGF-1 neutralizing antibodies resulted in a significant decrease in Kir1.1, Kv2.1, KV1.4, CCHL2a and SCN2a1 channel mRNA expression. Similarly, MSC(GATA-4) treated with VEGF neutralizing antibodies also resulted in an attenuated expression of Kv2.1, Kv1.2, Kv1.4, Kir1.1, CCHL2a and SCN2a1 channel mRNAs. CONCLUSIONS: GATA-4 overexpression increases Ito, IKDR, IK1, INa.TTX and ICa.L currents in MSC. Cytokine (VGEF and IGF-1) release from GATA-4 overexpressing MSC can partially account for the upregulated ion channel mRNA expression. GENERAL SIGNIFICANCE: Our results highlight the ability of GATA4 to boost the cardiac electrophysiological potential of MSC.

KCNN3 SNP rs13376333 on Chromosome 1q21 Confers Increased Risk of Atrial Fibrillation.

To investigate the relationship between KCNN3 SNP (single-nucleotide polymorphism) rs13376333 and risk of atrial fibrillation (AF) and to provide evidence for prevention and treatment for AF.The PubMed, Embase, OVID, Cochrane library, CNKI, and Wan Fang databases were searched to identify studies on the relationship between KCNN3 SNP rs13376333 polymorphism and atrial fibrillation. Two authors performed independent article reviews and study quality assessment using the Newcastle-Ottawa Scale (NOS) checklist.Seven studies involving 24,339 individuals were included in the meta-analysis. The overall combined OR of rs13376333 polymorphism was observed for both lone AF (OR: 1.58 [95%CI: 1.37 to 1.82]; P < 0.001; I(2) = 47.0%) and total AF (OR: 1.33 [95%CI: 1.14 to 1.54]; P < 0.001; I(2) = 0). Further, when stratified by ethnicity, control sources, sample sizes, and genotyping method, similar results were observed in both subgroups. Sensitivity analysis revealed that the source of control was the source of the heterogeneity for lone AF. Omission of any single study had little effect on the combined risk estimate. No evidence of publication bias was found.This meta-analysis suggests that KCNN3 SNP rs13376333 polymorphism significantly increases the risk of lone AF and total AF, which suggests the rs13376333 polymorphism of the KCNN3 gene may play an important role in the pathogenesis of AF.

Serum adropin level in patients with stable coronary artery disease.

OBJECTIVES: Adropin is a newly identified secreted protein implicated in the regulation of insulin sensitivity and vascular endothelial function. Recent studies have shown that lower serum adropin level is related to acute myocardial infarction and coronary atherosclerosis. The primary objective of this study was to ascertain the association of serum adropin level with stable coronary artery disease (SCAD). METHODS: We prospectively recruited a cohort of patients with SCAD and similar sample size subjects without coronary artery disease as controls. Their serum adropin levels were measured, and the severity of coronary atherosclerosis in SCAD patients was quantified with the syntax score. RESULTS: A total of 116 patients with SCAD and 116 control subjects without coronary artery disease were recruited. Patients with SCAD had lower serum adropin levels when compared with the controls (59.2±19.3 versus 70.0±18.2 pg/mL, P<0.001). The multiple logistic regression revealed that low serum adropin level was a significant predictor of SCAD (AOR 0.976, 95% CI 0.960-0.992; p=0.003). Through the gamma regression model, it was further revealed that serum adropin level is significantly associated with syntax score (coefficient: -0.134, 95% CI: -0.212- -0.056; p=0.001). CONCLUSIONS: Low serum adropin level is a significant predictor of SCAD. It is also associated with syntax score, thus indicating the close relationship between adropin and coronary atherosclerosis.

Triphenyltin chloride induces spindle microtubule depolymerisation and inhibits meiotic maturation in mouse oocytes.

Meiosis produces haploid gametes for sexual reproduction. Triphenyltin chloride (TPTCL) is a highly bioaccumulated and toxic environmental oestrogen; however, its effect on oocyte meiosis remains unknown. We examined the effect of TPTCL on mouse oocyte meiotic maturation in vitro and in vivo. In vitro, TPTCL inhibited germinal vesicle breakdown (GVBD) and first polar body extrusion (PBE) in a dose-dependent manner. The spindle microtubules completely disassembled and the chromosomes condensed after oocytes were exposed to 5 or 10µgmL(-1) TPTCL. γ-Tubulin protein was abnormally localised near chromosomes rather than on the spindle poles. In vivo, mice received TPTCL by oral gavage for 10 days. The general condition of the mice deteriorated and the ovary coefficient was reduced (P<0.05). The number of secondary and mature ovarian follicles was significantly reduced by 10mgkg(-1) TPTCL (P<0.05). GVBD decreased in a non-significant, dose-dependent manner (P>0.05). PBE was inhibited with 10mgkg(-1) TPTCL (P<0.05). The spindles of in vitro and in vivo metaphase II oocytes were disassembled with 10mgkg(-1) TPTCL. These results suggest that TPTCL seriously affects meiotic maturation by disturbing cell-cycle progression, disturbing the microtubule cytoskeleton and inhibiting follicle development in mouse oocytes.

GATA-4 protects against hypoxia-induced cardiomyocyte injury: effects on mitochondrial membrane potential.

Our previous studies have suggested that GATA-4 increases the differentiation of bone-marrow-derived mesenchymal stem cells (MSCs) into cardiac phenotypes. This study further investigated whether GATA-4 enhances MSC-mediated cardioprotection following hypoxia. MSCs were harvested from rat bone marrow and transduced with GATA-4 (MSC(GATA-4)). To mimic ischemic injury, cultured cardiomyocytes (CMs) isolated from neonatal rat ventricles were exposed to hypoxia or were pretreated with concentrated conditioned medium (CdM) from MSC(GATA-4) or transduced control MSC (MSC(Null)) for 16 h before exposure to hypoxic culture conditions (low glucose and low oxygen). Myocyte damage was estimated by annexin-V-PE and TUNEL technique and by lactate dehydrogenase (LDH) release. Cell survival was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5- diphenyltetrazolium (MTT) uptake. Mitochondrial membrane potential was determined using confocal microscopy. ELISA studies indicated that insulin-like growth factor 1 (IGF-1) and vascular endothelial growth factor (VEGF) were significantly increased in MSC(GATA-4) compared with MSC(Null). Hypoxia-induced apoptosis/cell death was significantly reduced when CMs were co-cultured with MSC(GATA-4) in a dual-chamber system. Cell protection mediated by MSC(GATA-4) was mimicked by treating CMs with CdM from MSC(GATA-4) and abrogated with IGF-1- and VEGF-neutralizing antibodies. MSC(GATA-4) protects CMs under hypoxic conditions. The release of IGF-1 and VEGF from MSC(GATA-4) is likely to be responsible for protection of CMs.

[Mechanism of gold solid extraction from aurocyanide solution using D3520 resin impregnated with TRPO].

Trialkyphosphine oxides (TRPO) was successfully used for the impregnation of D3520 resin to prepare an extractant-impregnated resin (EIR). Solid extraction of Au(I) from alkaline cyanide solution was studied using this extractant-impregnated resin (EIR), with addition of cetyltrimethylammonium bromide (CTMAB), directly into the aurous aqueous phase in advance. The mechanism of solid extraction was further investigated by means of FTIR, XPS and SEM. The column separation studies have shown that cationic surfactant CTMAB played a key role in the solid phase extraction, and the resin containing TRPO were effective for the extraction of gold when the molar ratio of CTMAB: Au( I ) reached 1:1. FTIR spectroscopy of gold loaded EIR showed that the frequency of C[triple bond]N stretching vibration was at 2144 cm(-1), and the frequency of P=O stretching vibration shifted to lower frequency from 1153 to 1150 cm(-1). The XPS spectrum of N(1s), Au(4f7/2) and Au(4f5/2) sugges- ted that the coordination environment of gold did not change before and after extraction, and gold was still as the form of Au (CN)2(-) anion exiting in the loaded resin; O(1s) spectrum showed that the chemically combined water significantly increased after solid extraction from 30.74% to 42.34%; Comparing to the P(2p) spectrum before and after extraction, the binding energy increased from 132. 15 to 132. 45 eV, indicating there maybe existing hydrogen-bond interaction between P=O and water molecule, such as P=O...H-O-H. The above results obtained established that in the solid extraction process, the hydrophobic ion association [CTMA+ x Au(CN)] diffused from the bulk solution into the pores of the EIR, and then be solvated by TRPO adsorbed in the pores through hydrogen bonding bridged by the water molecules.

Sanwei sandalwood decoction ameliorates acute ischemiareperfusion injury in rats by modulating myocyte electrophysiological characteristics.

Sanwei sandalwood decoction (SWTX) is a classical Chinese medicine formula and clinically effective treatment for coronary heart disease, including myocardial ischemia/reperfusion (I/R) injury. Because the treatment mechanism of SWTX in I/R injury remains obscure, we intended to analyze the potential cardioprotective effects of SWTX in rats with myocardial I/R injury. Our research revealed that SWTX prolonged ventricular conduction time in a dose-dependent manner. While SWTX significantly delayed left ventricular signal conduction velocity, it had no effect on left atrial conduction velocity. Under sinus conditions, low SWTX concentrations reduced left ventricular conduction dispersion, while high concentrations increased conduction dispersion. SWTX also prolonged the QRS interval, APD30/50/90, and ERP. In whole-cell patch clamp experiments on myocytes, Ito and Ikr were inhibited by SWTX. While SWTX had no effect on INa, the activation curve for Nav1.5 was left-shifted. Finally, SWTX reduced the probability of ventricular fibrillation and suppressed early and late depolarization in an acute I/R injury rat model. These findings shed light on the mechanism by which SWTX alleviates myocardial I/R injury.

[Effects of Mongolian medicine Shaosha-7 on myocardial ischemia/ reperfusion injury of rats].

Objective: To investigate the effects of Shaosha-7 in rats with myocardial ischemia-reperfusion injury and its mechanisms. Methods: male SD rats were divided into sham operation group (n=10), myocardial ischemia-reperfusion injury group (n=10), low, medium and high dose of Shaosha-7 groups (n=10), and positive drug group (n=10). The rats of Shaosha-7 (low, medium and high dose) groups were treated with Shaosha-7 at the doses of 0.4, 0.8 and 1.6 g/kg respectively, once a day for 15 days. The rats of positive drug group were treated with 0.3 g/kg Danshen, once a day for 15 days. The rats of the sham operation group and myocardial ischemia-reperfusion injury were treated with 2 ml/100 g distilled water, once a day for 15 days. After 15 days, the rats of the model group and the treatment group underwent thoracotomy and ligation of coronary artery for 30 minutes, then thoracic cavity was closed after reperfusion. Rats in six groups were executed electrocardiographic examination and their hearts were taken for Hematoxylin-Eosin (HE) staining and 2, 3, 5-triphenyltetrazolium chloride (TTC) staining to observe infarct area and myocardial pathological changes. The contents of cTnI, CK-MB, LDH, MDA, SOD, GSH-Px, TNF-α, IL-18, IL-6 and IL-1 ß in serum were detected by ELISA. The expression of NF-кB was detected by immunohistochemistry. Results: Compared with the sham operation group, the infarct size, the levels of cTnI, CK-MB, CK-MB, LDH, MDA, GSH-Px, TNF-α, IL-18, IL-6, IL-1ß and NF-кB were increased and the content of SOD were decreased in rats with myocardial ischemia-reperfusion injury. Compared with the rats with myocardial ischemia-reperfusion injury, Shaosha-7 improved the arrhythmia and pathological changes, reduced the infarct area, decreased the contents of cTnI, CK-MB, LDH, MDA, GSH-Px, TNF-α, IL-18, IL-6, IL-1 ß, increased the content of SOD, decreased the expression of NF-кB. Conclusion: Mongolian medicine Shaosha-7 can effectively alleviate myocardial ischemia-reperfusion injury in rats. This study provides a theoretical basis for the treatment of myocardial ischemia-reperfusion (I/R) injury with Shaosha-7.

Perfluorodecanoic acid induces meiotic defects and deterioration of mice oocytes in vitro.

Perfluorodecanoic acid (PFDA) is a member of the perfluoroalkyl substances, which are toxic to organic functions. Recently, it has been found in follicular fluid, seriously interfering with reproduction. Follicular fluid provides the oocyte with necessary resources during the process of oocytes maturation. However, the effects of PFDA on the oocyte need investigation. Our study evaluated the impacts of PFDA on the meiosis and development potential of mouse oocytes by exposing oocytes to PFDA in vitro at 350, 400, and 450 µM concentrations. The results showed that exposure to PFDA resulted in the first meiotic prophase arrest by obstructing the function of the maturation-promoting factor. It also induced the dysfunction of the spindle assembly checkpoint, expedited the progression of the first meiotic process, and increased the risk of aneuploidy. The oocytes treated with PFDA had a broken cytoskeleton which also contributed to meiotic maturation failure. Besides, PFDA exposure caused mitochondria defections, increased the reactive oxygen species level in oocytes, and consequently induced oocyte apoptosis. Moreover, PFDA produced epigenetic modifications in oocytes and increased the frequency of mature oocytes with declined development potential. In summary, our data indicated that PFDA disturbs the meiotic process and induces oocyte quality deterioration.

Docosahexaenoic acid has influence on action potentials and transient outward potassium currents of ventricular myocytes.

BACKGROUND: There are many reports about the anti-arrhythmic effects of omega-3 polyunsaturated fatty acids, however, the mechanisms are still not completely delineated. The purpose of this study was to investigate the characteristics of action potentials and transient outward potassium currents (Ito) of Sprague-Dawley rat ventricular myocytes and the effects of docosahexaenoic acid (DHA) on action potentials and Ito. METHODS: The calcium-tolerant rat ventricular myocytes were isolated by enzyme digestion. Action potentials and Ito of epicardial, mid-cardial and endocardial ventricular myocytes were recorded by whole-cell patch clamp technique. RESULTS: 1. Action potential durations (APDs) were prolonged from epicardial to endocardial ventricular myocytes (P < 0.05). 2. Ito current densities were decreased from epicardial to endocardial ventricular myocytes, which were 59.50 +/- 15.99 pA/pF, 29.15 +/- 5.53 pA/pF, and 12.29 +/- 3.62 pA/pF, respectively at +70 mV test potential (P < 0.05). 3. APDs were gradually prolonged with the increase of DHA concentrations from 1 micromol/L to 100 micromol/L, however, APDs changes were not significant as DHA concentrations were in the range of 0 micromol/L to 1 micromol/L. 4. Ito currents were gradually reduced with the increase of DHA concentrations from 1 micromol/L to 100 micromol/L, and its half-inhibited concentration was 5.3 micromol/L. The results showed that there were regional differences in the distribution of action potentials and Ito in rat epicardial, mid-cardial and endocardial ventricular myocytes. APDs were prolonged and Ito current densities were gradually reduced with the increase of DHA concentrations. CONCLUSION: The anti-arrhythmia mechanisms of DHA are complex, however, the effects of DHA on action potentials and Ito may be one of the important causes.

Serum parathyroid hormone levels in patients with chronic right heart failure.

Parathyroid hormone (PTH) is a novel cardiovascular biomarker which is particularly useful for detection and assessment of heart failure (HF). However, previous studies examining PTH in heart failure have primarily focused on left HF; thus, the relationship between PTH and right HF remains unclear. The aim of the present study was to evaluate the serum PTH levels in patients with chronic right HF. A total of 154 patients with chronic right HF were enrolled in the present study. A binary logistic regression analysis model was used to assess the independent predictive value of PTH levels in chronic right HF. Partial correlative analysis was used to demonstrate the relevance of PTH levels on the parameters of assessment of right heart function. A multiple linear regression analysis model was used to evaluate the independent factors of PTH levels in patients with right HF. The results showed that the serum PTH levels in the right HF group were significantly higher compared with the control group. After adjusting for predictors of right HF, serum PTH levels were associated with right HF with an odds ratio of 1.066 (95% confidence interval: 1.030-1.102, P<0.001. Serum PTH levels were independently correlated with plasma N-terminal pro-B-type natriuretic peptide levels, right ventricular end-diastolic diameter and severity of lower extremity edema (all P<0.05). Therefore, based on the results of the present study, PTH may be a useful biomarker for detection and assessment of right HF.

Effects of docosahexaenoic acid on large-conductance Ca2+-activated K+ channels and voltage-dependent K+ channels in rat coronary artery smooth muscle cells.

AIM: To investigate the effects of docosahexaenoic acid (DHA) on large-conductance Ca(2+)-activated K(+)(BK(Ca)) channels and voltage-dependent K(+) (K(V)) channels in rat coronary artery smooth muscle cells (CASMCs). METHODS: Rat CASMCs were isolated by an enzyme digestion method. BK(Ca) and K(V) currents in individual CASMCs were recorded by the patch-clamp technique in a whole-cell configuration at room temperature. Effects of DHA on BK(Ca) and K(V) channels were observed when it was applied at 10, 20, 30, 40, 50, 60, 70, and 80 micromol/L. RESULTS: When DHA concentrations were greater than 10 micromol/L, BK(Ca) currents increased in a dose-dependent manner. At a testing potential of +80 mV, 6.1%+/-0.3%, 76.5%+/-3.8%, 120.6%+/-5.5%, 248.0%+/-12.3%, 348.7%+/-17.3%, 374.2%+/-18.7%, 432.2%+/-21.6%, and 443.1%+/-22.1% of BK(Ca) currents were increased at the above concentrations, respectively. The half-effective concentration (EC(50)) of DHA on BK(Ca) currents was 37.53+/-1.65 micromol/L. When DHA concentrations were greater than 20 micromol/L, K(V) currents were gradually blocked by increasing concentrations of DHA. At a testing potential of +50 mV, 0.40%+/-0.02%, 1.37%+/-0.06%, 11.80%+/-0.59%, 26.50%+/-1.75%, 56.50%+/-2.89%, 73.30%+/-3.66%, 79.70%+/-3.94%, and 78.1%+/-3.91% of K(V) currents were blocked at the different concentrations listed above, respectively. The EC(50) of DHA on K(V) currents was 44.20+/-0.63 micromol/L. CONCLUSION: DHA can activate BK(Ca) channels and block K(V) channels in rat CASMCs, and the EC(50) of DHA for BK(Ca) channels is lower than that for K(V) channels; these findings indicate that the vasorelaxation effects of DHA on vascular smooth muscle cells are mainly due to its activation of BK(Ca) channels.

[Defibrillation efficacy of a newly developed automated external defibrillator in a swine ventricular tachycardia/fibrillation model].

OBJECTIVE: The aim of this study was to evaluate the recognition and defibrillation efficiency of a newly developed automated external defibrillator (AED). METHOD: Ventricular tachycardia (VT)/ventricular fibrillation (VF) was induced by alternating current (50 Hz) through an electrode placed on apex of right ventricle in 23 anesthetized swine and recorded, recognized and defibrillated by a newly developed AED. RESULTS: A total of 96 VF was induced and 145 defibrillations were recorded. We analyzed available 167 electrocardiosignal with a total length of 103,740 seconds. The accuracy, sensitivity and the specificity of the AED on VT/VF recognition are 99.5%, 98.2% and 99.6%, respectively. The success rate of defibrillation was 33.4% which increased in proportion to defibrillation energy. The defibrillation threshold of energy is 29.10-116.91 (78.75 +/- 35.64) J, the defibrillation threshold of electric quantity is (0.11 +/- 0.04) C and the defibrillation threshold of voltage is (1216.67 +/- 260.87) V. CONCLUSIONS: This newly developed AED has high sensitivity and the specificity on recognizing VT/VF. The lower success rate of defibrillation of this AED is associated with the low defibrillation energy during defibrillation which needs to be improved on further development.

[Effects of docosahexaenoic acid on action potential and transient outward potassium current on ventricular myocytes of Sprague-Dawley rat].

OBJECTIVE: To investigate the effects of docosahexaenoic acid (DHA) on action potential (AP) and transient outward potassium current (I(to)) on ventricular myocytes of Sprague-Dawley rat. METHODS: Calcium-tolerant ventricular myocytes were isolated by enzyme digestion. The changes of AP and I(to) with increasing DHA at concentrations of 0, 10, 20, 40, 60, 80, 100, 120 and 200 micromol/L were recorded by whole-cell patch clamp configuration. RESULTS: (1) Action potential durations (APDs) were not affected by DHA at concentrations from 0 micromol/L to 30 micromol/L, while APDs were gradually prolonged in proportion with increasing DHA concentrations from 30 micromol/L to 200 micromol/L within 5 minutes and remained stable thereafter. APD(25), APD(50) and APD(75) were (7.7 +/- 2.0) ms, (21.2 +/- 3.5) ms, and (100.1 +/- 9.8) ms respectively at 100 micromol/L DHA. APD(25), APD(50), and APD(75) were (15.2 +/- 4.0) ms, (45.7 +/- 6.8) ms, and (215.6 +/- 15.7) ms respectively at 200 micromol/L DHA. (2) I(to) was gradually reduced with the increasing DHA concentrations from 10 micromol/L to 200 micromol/L. I(to) was blocked by DHA in a dose-dependent manner. I(to) current density was (30.1 +/- 7.2) pA/pF at DHA concentration of 60 micromol/L and its half-inhibition concentration was 58.3 micromol/L. CONCLUSION: APDs are gradually prolonged while I(to) reduced with increasing concentrations of DHA which might contribute to the anti-arrhythmia mechanisms of DHA.

Comparisons of efficacy, safety, and recurrence risk factors of paroxysmal and persistent atrial fibrillation catheter ablation using robotic magnetic navigation system.

BACKGROUND: No data exist on comparisons of efficacy, safety, and recurrence risk factors of paroxysmal and persistent atrial fibrillation (AF) ablation using robotic magnetic navigation system (MNS), respectively. METHODS: About 151 AF patients were prospectively enrolled and divided into paroxysmal AF group (n = 102) and persistent AF group (n = 49). Circumferential pulmonary vein antrum isolation (CPVI) was performed in all patients. Linear ablation at the left atrial roof and mitral isthmus was performed in patients with persistent AF in addition to CPVI. The procedural time, X-ray exposure time, acute and long-term success rates of CPVI, and procedure-related complications were analyzed. The AF recurrence rates in the two groups were compared during 1 year, and Cox regression was used to analyze the recurrence risk factors. RESULTS: The acute success rates of CPVI in the two groups were 98.04% and 97.96%, respectively. There were no significant differences in the procedural time, X-ray exposure time, and ablation time between the two groups (P > 0.05). No serious complications appeared in either group. The AF ablation success rates were 70.6% and 57.1% for the paroxysmal and persistent groups respectively at 12-month follow-up (P = 0.102). AF duration and coronary heart disease prior to ablation were associated with the higher AF recurrence in patients with persistent AF. CONCLUSION: Ablation using MNS is effective and safe both in patients with paroxysmal and persistent AF. AF duration and coronary heart disease prior to ablation are two independent risk factors of AF recurrence in patients with persistent AF postoperatively.