Effect of puerarin supplementation on cardiovascular disease risk factors: A randomized, double-blind, placebo-controlled, 2-way crossover trial.

BACKGROUND: Cell culture and animal studies suggest puerarin could prevent cardiovascular disease (CVD). However, trials in human are scare, not primarily designed for prevention, and inadequately powered. We assessed the effect of puerarin supplementation on CVD risk factors in men using a crossover trial. METHODS: In total, 217 Chinese men aged 18-50 years without a history of CVD were recruited. They were randomized to take a puerarin supplement (90.2 mg daily) or a placebo, followed by a 4-week wash-out period, and then crossed over to the other intervention. An intention-to-treat analysis was used. Differences in primary outcomes (lipid profile such as low-density lipoprotein (LDL) cholesterol) and secondary outcomes (other CVD risk factors such as blood pressure and fasting glucose, and some potential mediating pathways such as testosterone) between supplementation and placebo within participants were compared using a paired t-test, or a crossover (CROS)-based analysis where a period effect existed. RESULTS: Lipid profile was similar after the puerarin supplementation or placebo (e.g., mean difference in LDL cholesterol: -0.02 mmol/L, 95% confidence interval (CI) -0.09 to -0.06). Conversely, fasting glucose was reduced after the puerarin supplementation (-0.13 mmol/L, 95% CI -0.25 to -0.008). There were no differences in blood pressure, testosterone, high-sensitive C-reactive protein, prothrombin time, liver or renal function. CONCLUSION: In young-to-middle-aged Chinese men, short-term puerarin supplementation did not improve the primary outcome of lipid profile, but an exploratory analysis suggested that puerarin could be beneficial for one of the secondary outcomes, i.e., fasting glucose.

Application of Patient-Specific iPSCs for Modelling and Treatment of X-Linked Cardiomyopathies.

Inherited cardiomyopathies are among the major causes of heart failure and associated with significant mortality and morbidity. Currently, over 70 genes have been linked to the etiology of various forms of cardiomyopathy, some of which are X-linked. Due to the lack of appropriate cell and animal models, it has been difficult to model these X-linked cardiomyopathies. With the advancement of induced pluripotent stem cell (iPSC) technology, the ability to generate iPSC lines from patients with X-linked cardiomyopathy has facilitated in vitro modelling and drug testing for the condition. Nonetheless, due to the mosaicism of the X-chromosome inactivation, disease phenotypes of X-linked cardiomyopathy in heterozygous females are also usually more heterogeneous, with a broad spectrum of presentation. Recent advancements in iPSC procedures have enabled the isolation of cells with different lyonisation to generate isogenic disease and control cell lines. In this review, we will summarise the current strategies and examples of using an iPSC-based model to study different types of X-linked cardiomyopathy. The potential application of isogenic iPSC lines derived from a female patient with heterozygous Danon disease and drug screening will be demonstrated by our preliminary data. The limitations of an iPSC-derived cardiomyocyte-based platform will also be addressed.

Effect of Berberine on Cardiovascular Disease Risk Factors: A Mechanistic Randomized Controlled Trial.

Cardiovascular disease (CVD) is a major contributor to the global burden of disease. Berberine, a long-standing, widely used, traditional Chinese medicine, is thought to have beneficial effects on CVD risk factors and in women with polycystic ovary syndrome. The mechanisms and effects, specifically in men, possibly via testosterone, have not been examined previously. To assess the effect of berberine on CVD risk factors and any potential pathway via testosterone in men, we conducted a randomized, double-blind, placebo-controlled, parallel trial in Hong Kong. In total, 84 eligible Chinese men with hyperlipidemia were randomized to berberine (500 mg orally, twice a day) or placebo for 12 weeks. CVD risk factors (lipids, thromboxane A2, blood pressure, body mass index and waist-hip ratio) and testosterone were assessed at baseline, and 8 and 12 weeks after intervention. We compared changes in CVD risk factors and testosterone after 12 weeks of intervention using analysis of variance, and after 8 and 12 weeks using generalized estimating equations (GEE). Of the 84 men randomized, 80 men completed the trial. Men randomized to berberine had larger reductions in total cholesterol (-0.39 mmol/L, 95% confidence interval (CI) -0.70 to -0.08) and high-density lipoprotein cholesterol (-0.07 mmol/L, 95% CI -0.13 to -0.01) after 12 weeks. Considering changes after 8 and 12 weeks together, berberine lowered total cholesterol and possibly low-density lipoprotein-cholesterol (LDL-c), and possibly increased testosterone. Changes in triglycerides, thromboxane A2, blood pressure, body mass index and waist-hip ratio after the intervention did not differ between the berberine and placebo groups. No serious adverse event was reported. Berberine is a promising treatment for lowering cholesterol. Berberine did not lower testosterone but instead may increase testosterone in men, suggesting sex-specific effects of berberine. Exploring other pathways and assessing sex differences would be worthwhile, with relevance to drug repositioning and healthcare.

Human-Induced Pluripotent Stem Cell-Derived Cardiomyocytes Platform to Study SARS-CoV-2 Related Myocardial Injury.

BACKGROUND: SARS-CoV-2 infection is associated with myocardial injury, but there is a paucity of experimental platforms for the condition.Methods and Results:Human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) infected by SARS-CoV-2 for 3 days ceased beating and exhibited cytopathogenic changes with reduced viability. Active viral replication was evidenced by an increase in supernatant SARS-CoV-2 and the presence of SARS-CoV-2 nucleocaspid protein within hiPSC-CMs. Expressions of BNP, CXCL1, CXCL2, IL-6, IL-8 and TNF-α were upregulated, while ACE2 was downregulated. CONCLUSIONS: Our hiPSC-CM-based in-vitro SARS-CoV-2 myocarditis model recapitulated the cytopathogenic effects and cytokine/chemokine response. It could be exploited as a drug screening platform.

Non-vitamin K Oral Anticoagulants Versus Warfarin for Patients with Atrial Fibrillation: Absolute Benefit and Harm Assessments Yield Novel Insights.

BACKGROUND AND OBJECTIVES: Benefits and/or harms (including costs) of non-vitamin K oral anticoagulants (NOACs) versus warfarin therapy need appreciation in relative and absolute terms. METHODS: Accordingly, we derived clinically relevant relative and absolute benefit/harm parameters for NOACs (apixaban, dabigatran, rivaroxaban, edoxaban) compared to warfarin from four clinical trials involving atrial fibrillation (AF) patients. For each trial, we tabulated patient numbers enduring four important outcomes and calculated unadjusted relative risk reduction (RRR) and number needed to treat (NNT)/year values (and 95% confidence intervals) for the NAOC compared to warfarin. These outcomes were as follows: stroke/systemic embolism (primary endpoint), hemorrhagic stroke, major bleeds, and death. We also addressed drug acquisition costs. RESULTS: Each NOAC was noninferior to warfarin for primary-outcome prevention; RRRs were 12-33% and NNT/year values were 182-481, and all but one indicated statistically significant superiority. All the NOACs yielded statistically significant reductions in hemorrhagic stroke risk; RRRs were 42-74% and NNT/year values were 364-528. Major bleeding risk was comparable in both groups. Apixaban yielded a lower NNT/year for preventing death than for primary-outcome prevention. Compared to warfarin, NOAC acquisition costs were 70- to 140-fold greater. CONCLUSIONS: For the primary outcome, the absolute benefits of NOACs were modest (NNT/year values being large). Reduced hemorrhagic stroke rates with NOACs could be due to superior embolic infarct prevention and fewer consequential hemorrhagic transformations. Among apixaban recipients, the absolute mortality benefit exceeded that for the primary outcome, indicating prevention of additional unrelated deaths. The substantially greater NOAC acquisition costs need viewing against probable greater safety and the avoidance of monitoring bleeding risks.

Efficient attenuation of Friedreich's ataxia (FRDA) cardiomyopathy by modulation of iron homeostasis-human induced pluripotent stem cell (hiPSC) as a drug screening platform for FRDA.

BACKGROUND: Friedreich's ataxia (FRDA), a recessive neurodegenerative disorder commonly associated with hypertrophic cardiomyopathy, is caused by silencing of the frataxin (FXN) gene encoding the mitochondrial protein involved in iron-sulfur cluster biosynthesis. METHODS: Application of our previously established FRDA human induced pluripotent stem cell (hiPSC) derived cardiomyocytes model as a platform to assess the efficacy of treatment with either the antioxidant coenzyme Q10 analog, idebenone (IDE) or the iron chelator, deferiprone (DFP), which are both under clinical trial. RESULTS: DFP was able to more significantly suppress synthesis of reactive oxygen species (ROS) than IDE at the dosages of 25 µM and 10nM respectively which agreed with the reduced rate of intracellular accumulation of iron by DFP treatment from 25 to 50 µM. With regard to cardiac electrical-contraction (EC) coupling function, decay velocity of calcium handling kinetics in FRDA-hiPSC-cardiomyocytes was significantly improved by DFP treatment but not by IDE. Further mechanistic studies revealed that DFP also modulated iron induced mitochondrial stress as reflected by mitochondria network disorganization and decline level of respiratory chain protein, succinate dehydrogenase (CxII) and cytochrome c oxidase (COXIV). In addition, iron-response protein (IRP-1) regulatory loop was overridden by DFP as reflected by resumed level of ferritin (FTH) back to basal level and the attenuated transferrin receptor (TSFR) mRNA level suppression thereby reducing further iron uptake. CONCLUSIONS: DFP modulated iron homeostasis in FRDA-hiPSC-cardiomyocytes and effectively relieved stress-stimulation related to cardiomyopathy. The resuming of redox condition led to the significantly improved cardiac prime events, cardiac electrical-coupling during contraction.

Plant Natural Products Calycosin and Gallic Acid Synergistically Attenuate Neutrophil Infiltration and Subsequent Injury in Isoproterenol-Induced Myocardial Infarction: A Possible Role for Leukotriene B4 12-Hydroxydehydrogenase?

Leukotriene B4 12-hydroxydehydrogenase (LTB4DH) catalyzes the oxidation of proinflammatory LTB4 into less bioactive 12-oxo-LTB4. We recently discovered that LTB4DH was induced by two different natural products in combination. We previously isolated gallic acid from Radix Paeoniae through a bioactivity-guided fractionation procedure. The purpose of this study is to test the hypothesis that LTB4DH inducers may suppress neutrophil-mediated inflammation in myocardial infarction. We first isolated the active compound(s) from another plant, Radix Astragali, by the similar strategy. By evaluating LTB4DH induction, we identified calycosin and formononetin from Radix Astragali by HPLC-ESI-MS technique. We confirmed that gallic acid and commercial calycosin or formononetin could synergistically induce LTB4DH expression in HepG2 cells and human neutrophils. Moreover, calycosin and gallic acid attenuated the effects of LTB4 on the survival and chemotaxis of neutrophil cell culture. We further demonstrated that calycosin and gallic acid synergistically suppressed neutrophil infiltration and protected cardiac integrity in the isoproterenol-induced mice model of myocardial infarction. Calycosin and gallic acid dramatically suppressed isoproterenol-induced increase in myeloperoxidase (MPO) activity and malondialdehyde (MDA) level. Collectively, our results suggest that LTB4DH inducers (i.e., calycosin and gallic acid) may be a novel combined therapy for the treatment of neutrophil-mediated myocardial injury.

Prospective randomized comparison between a fixed '2C3L' approach vs. stepwise approach for catheter ablation of persistent atrial fibrillation.

AIMS: This prospective clinical trial was designed to evaluate the efficacy of an ablation strategy, namely '2C3L', in the treatment of persistent atrial fibrillation (AF); and to compare its efficacy with that of the 'stepwise' approach, which has been acknowledged as a promising ablation technique for persistent AF. METHODS AND RESULTS: The '2C3L' technique is a fixed ablation approach consisting of bilateral circumferential pulmonary vein antrum isolation (PVAI) and three linear ablation lesion sets across the mitral isthmus, left atrial roof, and cavo-tricuspid isthmus. One hundred and forty-six patients with persistent AF were randomized to undergo ablation by using the '2C3L' or the 'stepwise' technique (n = 73, respectively). The primary endpoint was freedom from any atrial tachyarrhythmia off antiarrhythmic drug (AAD) after a single procedure at follow-up. Twelve months after a single procedure, there was no difference in sinus rhythm (SR) maintenance rate between the two groups (67% for '2C3L' vs. 60% for 'stepwise', P = 0.394; 95% confidence interval of between-group difference -8.7 to 22.4%). The procedure (222 ± 42 vs. 263 ± 41 min), fluoroscopy (41 ± 9 vs. 55 ± 8 min), and radiofrequency (RF) (107 ± 32 vs. 128 ± 38 min) time were significantly shorter in the '2C3L' group (all P < 0.001). At 25 ± 5 months after the first procedure, 57.5 and 52.1% of patients from the '2C3L' group and the 'stepwise' group were in SR off AAD (P = 0.494), respectively. CONCLUSIONS: For catheter ablation of persistent AF, the '2C3L' strategy is a fixed approach associated with clinical efficacy similar to that of the 'stepwise' approach but with less RF delivery, fewer X-ray exposure, and shorter procedural time.

Randomized controlled trial of vitamin D supplement on endothelial function in patients with type 2 diabetes.

BACKGROUND: Suboptimal vitamin D status is associated with endothelial dysfunction and an increased risk of cardiovascular diseases but it is unclear whether vitamin D supplementation is beneficial. The aim was to investigate the effect of vitamin D supplementation on endothelial function in patients with type 2 diabetes mellitus (DM). METHODS: In a double-blind, placebo-controlled trial, we randomized 100 type 2 DM patients to vitamin D supplement (5000 IU/day, n = 50) or placebo (controls, n = 50) for 12 weeks. Assessment of vascular function with brachial artery flow-mediated dilatation (FMD), circulating levels of endothelial progenitor cells (EPCs) and brachial-ankle pulse wave velocity, and metabolic parameter, high-sensitivity C-reactive protein (hsCRP) and oxidative stress markers were performed before and after the supplementation. RESULTS: After 12 weeks, vitamin D treated patients had significant increases in serum 25-hydroxyvitamin D [25(OH)D] concentration (treatment effect 34.7 ng/mL, 95% CI 26.4-42.9, P < 0.001) and serum ionized calcium (treatment effect 0.037 mmol/L, 95% CI 0.007-0.067, P = 0.018); decreased serum parathyroid hormone concentration (treatment effect -0.55 pmol/L, 95% CI -1.08 to -0.02, P = 0.042) compared to patients who received placebo. Nevertheless, vitamin D supplementation did not improve vascular function as determined by FMD, circulating EPC count or baPWV (all P > 0.05). Furthermore, hsCRP, oxidative stress markers, low- and high-density lipoprotein and glycated hemoglobin were also similar between two groups (all P > 0.05). CONCLUSION: In patients with type 2 DM, 12 weeks oral supplementation of vitamin D did not significantly affect vascular function or serum biomarkers of inflammation and oxidative stress. CLINICAL TRIAL NUMBER: HKCTR-867, www.hkclinicaltrials.com.

Thoracic spinal cord stimulation improves cardiac contractile function and myocardial oxygen consumption in a porcine model of ischemic heart failure.

BACKGROUND: Prior experimental studies show that thoracic spinal cord stimulation (SCS) improves left ventricular (LV) ejection fraction (LVEF). The mechanism of this improvement in the LV contractile function after SCS and its effects on the myocardial oxygen consumption remains unknown. METHODS AND RESULTS: We performed thoracic SCS (T1-T2 level) followed by 4 weeks of rapid ventricular pacing in 9 adult pigs with ischemic heart failure (HF) induced by myocardial infarction (MI). At 24 hours off-pacing, detailed echocardiogram and invasive hemodynamic assessment were performed to determine LV contractile function and myocardial oxygen consumption. Serum norepinephrine level was measured before and after SCS. SCS was performed on 2 occasions for 15 minutes, 30 minutes apart (recovery) with 50 Hz frequency (pulse width 0.2 millisecond, 90% of motor threshold at 2 Hz output). Echocardiogram revealed significant decrease in LVEF (33.8 ± 1.8% vs 66.5 ± 1.7%, P < 0.01) after induction of MI and HF. Compared with MI and HF, acute SCS significantly increased LVEF and +dP/dt (all P < 0.05). Withdrawal of SCS during recovery decreased +dP/dt, but not LVEF that increased again with repeated SCS. Myocardial oxygen consumption also significantly decreased during SCS compared with MI and HF (P = 0.006) without any change in serum norepinephrine level (P = 0.9). Speckle tracking imaging showed significant improvement in global and regional circumferential strains over the infarcted mid and apical regions, decreased in time to peak circumferential strain over the lateral and posterior wall after SCS, and the degree of intraventricular dyssynchrony during SCS compared with MI and HF (P < 0.05). CONCLUSIONS: In a porcine model of ischemic HF, acute SCS improved global and regional LV contractile function and intraventricular dyssynchrony, and decreased myocardial oxygen consumption without elevation of norepinephrine level.

Effect of herbal consumption on time in therapeutic range of warfarin therapy in patients with atrial fibrillation.

It has been established that herbal intake affects the anticoagulation effects of warfarin, but the long-term impact on anticoagulation control is unclear. We sought to investigate the effect of concomitant herbal intake on anticoagulation control in patients with nonvalvular atrial fibrillation (AF) treated with warfarin. The effects of common herbs were determined by monitoring the international normalized ratio in 250 patients with AF (69 ± 10 years, 50% male). All the patients had been prescribed warfarin therapy for at least 6 months before enrollment, and their dietary intake, including the type and the frequency of common herbs, was recorded using a standardized questionnaire. Up to 50% of the patients reported consumption of foods with herbal ingredients, including garlic (80.4%), ginger (74.8%), green tea (50.4%), and papaya (55.2%) but rarely herbal drugs such as danshen (1.2%), dong guai (0.8%), fenugreek (1.2%), psyllium seed (0.4%), and ginseng (4%). Infrequent users (1 kind of herb for <4 times per week and nonusers) were more likely to have an international normalized ratio within the optimal therapeutic range (2.0-3.0) than frequent users (>1 kind of herb for ≥4 times per week) (58.1% vs 51.1%, P = 0.046). In conclusion, the patients with AF treated with warfarin had little knowledge about the potential interaction of herbal substances in foods with warfarin. The patients who consumed common herbs at least 4 times per week had suboptimal anticoagulation control with warfarin.

Randomized comparison between pulmonary vein antral isolation versus complex fractionated electrogram ablation for paroxysmal atrial fibrillation.

INTRODUCTION: Circumferential pulmonary vein antral isolation (PVAI) and atrial complex fractionated electrograms (CFEs) are both ablative techniques for the treatment of paroxysmal atrial fibrillation (PAF). However, data on the comparative value of these 2 ablation strategies are very limited. METHODS AND RESULTS: We randomized 118 patients with drug-refractory PAF to receive PVAI ablation (n = 60) or CFE ablation (n = 58). For CFE group, spontaneous/induced AF was mapped using validated, automated software to guide ablation until all CFE areas were eliminated. For PVAI group, all 4 pulmonary vein antra were electrically isolated as confirmed by circular mapping catheter. Patients with spontaneous/inducible AF after the initial ablation procedure were crossed over to the other arms. After initial ablation procedure, AF persisted/inducible in 24/59 patients (41%), and 34/58 patients (59%) assigned to PVAI and CFE ablation, respectively (P = 0.05). Then 58 patients underwent PVAI + CFE ablation. After 22.6 ± 6.4 months, PVAI ablation group was more likely than CFE ablation group to achieve control of any AF/atrial tachycardia (AT) off drugs (43/60, 72% vs 33/58, 57%, P = 0.075) and lower recurrence rate of AT (11.9% vs 34.5%, P = 0.004). Patients who received CFE ablation alone (38%) had significantly lower overall success rate to achieve control of AF/AT off drugs compared with patients who received PVAI ablation (77%, P = 0.002) alone or PVAI + CFE ablation (69%, P = 0.008) due to higher recurrence rate of AT (50% vs 6% vs 13%, P < 0.01). CONCLUSIONS: CFE ablation in PAF patients was associated with higher occurrence rate of postprocedure AT compared with PVAI ablation, whereby making it less likely to be a sole ablation strategy for PAF patients.

Dietary intake of phytoestrogen is associated with increased circulating endothelial progenitor cells in patients with cardiovascular disease.

Endogenous estrogen is known to positively influence the level and functionality of endothelial progenitor cells (EPC). However, the effect of phytoestrogen on EPC is unknown. Isoflavone is a major component of phytoestrogen. This study aims to investigate if the intake of isoflavone has any impact on the circulating level of EPC. We studied 102 consecutive patients (mean age: 66.5 ± 9.5 years, 78% male, all female post-menopausal) with cardiovascular disease (atherothrombotic stroke 62%, coronary artery disease 38%). Circulating levels of CD133(+) EPC were determined by flow cytometry. Non-invasive pulse wave velocity (PWV) was measured. Long-term intake of isoflavone was determined by a validated food frequency questionnaire. Isoflavone intake was positively associated with circulating CD133(+) EPC (r = 0.31, p = 0.001). Patients with circulating CD133(+) EPC <10th percentile had significantly lower isoflavone intake than patients with CD133(+)EPC ≥10th percentile (4.6 ± 3.7 mg/day versus 19.3 ± 30.2 mg/day, p < 0.001). A significant overall linear trend of circulating EPC across increasing tertiles of isoflavone intake was observed (p = 0.004). Adjusted for potential confounders, increased isoflavone intake from the 1st to the 3rd tertile independently predicted increased circulating CD133(+) EPC level by 221 cells/µl (95%CI: 71.4 to 369.8, relative increase 160%, p = 0.004). Gender was not a significant factor (p > 0.05). Furthermore, circulating CD133(+) EPC <10th percentile was independently predictive of increased PWV by 261.7 cm/s (95% CI: 37.1 to 486.2, p = 0.024). The study demonstrated that circulating EPC increased by more than one fold in patients with cardiovascular disease who had higher intake of isoflavone, suggesting that isoflavone may confer vascular protection through enhanced endothelial repair.

Reversal of mitochondrial dysfunction by coenzyme Q10 supplement improves endothelial function in patients with ischaemic left ventricular systolic dysfunction: a randomized controlled trial.

AIMS: Coronary artery disease (CAD) is associated with endothelial dysfunction and mitochondrial dysfunction (MD). The aim of this study was to investigate whether co-enzyme Q10 (CoQ) supplementation, which is an obligatory coenzyme in the mitochondrial respiratory transport chain, can reverse MD and improve endothelial function in patients with ischaemic left ventricular systolic dysfunction (LVSD). METHODS AND RESULTS: We performed a randomized, double-blind, placebo-controlled trial to determine the effects of CoQ supplement (300 mg/day, n=28) vs. placebo (controls, n=28) for 8 weeks on brachial flow-mediated dilation (FMD) in patients with ischaemic LVSD(left ventricular ejection fraction <45%). Mitochondrial function was determined by plasma lactate/pyruvate ratio (LP ratio). After 8 weeks, CoQ-treated patients had significant increases in plasma CoQ concentration (treatment effect 2.20 µg/mL, P<0.001) and FMD (treatment effect 1.51%, P=0.03); and decrease in LP ratio (treatment effect -2.46, P=0.03) compared with controls. However, CoQ treatment did not alter nitroglycerin-mediated dilation, blood pressure, blood levels of fasting glucose, haemoglobin A1c, lipid profile, high-sensitivity C-reactive protein and oxidative stress as determined by serum superoxide dismutase and 8-isoprostane (all P>0.05). Furthermore, the reduction in LP ratio significantly correlated with improvement in FMD (r=-0.29, P=0.047). CONCLUSION: In patients with ischaemic LVSD, 8 weeks supplement of CoQ improved mitochondrial function and FMD; and the improvement of FMD correlated with the change in mitochondrial function, suggesting that CoQ improved endothelial function via reversal of mitochondrial dysfunction in patients with ischaemic LVSD.

Long-term clinical implication of the occurrence of dissociated pulmonary vein activities after circumferential left atrial ablation in patients with paroxysmal atrial fibrillation.

BACKGROUND: The incidence and clinical implication of dissociated pulmonary vein (PV) electrical activities after circumferential antrum PV ablation for paroxysmal atrial fibrillation (AF) remains unclear. METHODS AND RESULTS: A total of 196 patients with symptomatic paroxysmal AF who underwent circumferential antrum PV ablation were prospectively studied. Dissociated PV electrical activities were observed in 101 patients (Group 1), but absent in the remaining 95 patients (Group 2). There were no significant differences in the baseline clinical characteristics between them, except that Group 2 had a higher prevalence of hypertension (30 vs. 44%, P = 0.04). After 21.8 ± 7.9 months of follow-up, 148 had no recurrence of AF after the initial procedure. AF recurrence rate was significantly higher in Group 2 than in Group 1 (P = 0.023). Relapse of PV conduction was the major cause of AF recurrence in both groups (16/16 vs. 19/23, P = 0.08), and the overall procedural success rate after the redo ablation procedure was similar in the 2 groups (90 vs. 86%, P = 0.44). However, the total number of patients with non-PV foci was significantly higher in Group 2 than in Group 1 (12/95 vs. 2/101, P < 0.01). CONCLUSIONS: Dissociated PV electrical activities might identify a subgroup of patients with relatively higher initial procedural success with circumferential PV antrum ablation.

Proarrhythmic risk of embryonic stem cell-derived cardiomyocyte transplantation in infarcted myocardium.

BACKGROUND: Cellular replacement strategies using embryonic stem cells (ESCs) and their cardiac derivatives are emerging as novel experimental therapeutic paradigms for the treatment of post-myocardial infarction (MI) left ventricular (LV) dysfunction; however, their potential proarrhythmic risk remains unclear. OBJECTIVE: The purpose of this study was to investigate the functional effect and proarrhythmic risk of ESC transplantation in a mouse model of MI. METHODS: We compared the functional effects and proarrhythmic risk of direct intramyocardial transplantation of 3 × 10(5) undifferentiated mouse ESCs (MI+ESC group, n = 33) and mouse ESC-derived cardiomyocytes (MI+ESC-CM group, n = 40) versus culture medium (MI group, n = 33) at the infarct border zone in a mouse model of acute MI. LV performance was assessed with serial cardiac magnetic resonance imaging (MRI) at 1 and 3 week(s) post-MI, and invasive LV pressure measurement was assessed (dP/dt) at 4 weeks before sacrifice for histological examination. Furthermore, electrophysiological study was also performed in another set of animals in each group (n = 24) to assess for proarrhythmias after transplantation. RESULTS: In vitro cellular electrophysiological study demonstrated that ESC-CMs exhibit arrhythmogenesis including automaticity, lengthened action potential duration, and depolarized resting membrane potential. At 4 weeks, the MI+ESC-CM group (21/40, 53%) had a higher mortality rate compared with those in the MI group (10/33, 30%, P = .08) and in the MI+ESC group (7/33, 21%, P = .012). Electrophysiological study showed a significantly higher incidence of inducible ventricular tachyarrhythmias in the MI+ESC-CM group (13/24, 54%) compared with in the MI group (6/24, 21%, P = .039) and in the MI+ESC group (5/24, 21%, P = .017). Cardiac MRI showed similar improvement in LV ejection fraction in the MI+ESC and MI+ESC-CM groups compared with in the MI group at 1 week (27.5% ± 3.8%; 30.3% ± 5.2% vs. 12.4% ± 1.4%; P < .05) and 3 weeks (29.8% ± 3.9%; 27.0% ± 4.8% vs. 10.6% ± 2.8%; P < .05) post-MI, respectively. Furthermore, invasive hemodynamic assessment at 4 weeks showed significant similar improvement in LV +dP/dt in the MI+ESC (2,644 ± 391 mmHg/s, P < .05) and MI+ESC-CM groups (2,539 ± 389 mmHg/s; P < .05) compared with in the MI group (2,042 ± 406 mmHg/s). CONCLUSIONS: Our results demonstrate that transplantation of undifferentiated ESCs and ESC-CMs provides similar improvement in cardiac function post-MI. However, transplantation of ESC-CMs is associated with a significantly higher prevalence of inducible ventricular tachyarrhythmias and early mortality than transplantations with ESCs.

Triiodothyronine promotes cardiac differentiation and maturation of embryonic stem cells via the classical genomic pathway.

Embryonic stem cells (ESCs) can differentiate into functional cardiomyocytes and thus represent a promising cell source for cardiac regenerative therapy. Nevertheless, the therapeutic application of ESC-derived cardiomyocytes is limited by the low efficacy of the current protocol for cardiac differentiation and their immature phenotypes. Although thyroid hormone is essential for normal cardiac development and function, its role in the cardiac differentiation of ESCs, as well as the maturation of ESC-derived cardiomyocytes, remains unclear. In this study, we examined the cardiac differentiation of murine ESCs in the presence of T(3) for 7 d using flow cytometry, RT-PCR, cellular electrophysiology study, and confocal calcium imaging. Compared with control conditions, T(3) supplementation increased the number of ESC-derived cardiomyocytes and was accompanied by up-regulation of a panel of cardiac markers, including Nkx2.5, myosin light chain-2V, as well as alpha- and beta-myosin heavy chain. More importantly, electrophysiological study revealed that ESC-derived cardiomyocytes exhibited more adult-like phenotypes after T(3) supplementation based on action potential characteristics. They also exhibited more adult-like calcium homeostasis properties. These phenotypic changes were associated with up-regulation of sarco(endo)plasmic reticulum calcium ATPase-2a and ryanodine receptor-2 expression. In addition, the classical (genomic) pathway was shown to be involved in T(3)-induced cardiac differentiation of ESCs. Our results show that T(3) supplementation promotes cardiac differentiation of ESCs and enhances maturation of electrophysiological, as well as calcium homeostasis, properties of ESC-derived cardiomyocytes.

Future perspective of induced pluripotent stem cells for diagnosis, drug screening and treatment of human diseases.

Recent advances in stem cell biology have transformed the understanding of cell physiology and developmental biology such that it can now play a more prominent role in the clinical application of stem cell and regenerative medicine. Success in the generation of human induced pluripotent stem cells (iPS) as well as related emerging technology on the iPS platform provide great promise in the development of regenerative medicine. Human iPS cells show almost identical properties to human embryonic stem cells (ESC) in pluripotency, but avoid many of their limitations of use. In addition, investigations into reprogramming of somatic cells to pluripotent stem cells facilitate a deeper understanding of human stem cell biology. The iPS cell technology has offered a unique platform for studying the pathogenesis of human disease, pharmacological and toxicological testing, and cell-based therapy. Nevertheless, significant challenges remain to be overcome before the promise of human iPS cell technology can be realised.

Reduction of C-reactive protein with isoflavone supplement reverses endothelial dysfunction in patients with ischaemic stroke.

AIMS: To investigate the effect of oral isoflavone supplement on vascular endothelial function in patients with established cardiovascular disease. METHODS AND RESULTS: A randomized, double-blinded, placebo-controlled trial was performed to determine the effects of isoflavone supplement (80 mg/day, n = 50) vs. placebo (n = 52) for 12 weeks on brachial flow-mediated dilatation (FMD) in patients with prior ischaemic stroke. Compared with controls, FMD at 12 weeks was significantly greater in isoflavone-treated patients [treatment effect 1.0%, 95% confidence interval (95% CI) 0.1-2.0, P = 0.035]. Adjusted for baseline differences in FMD, isoflavone treatment was independently associated with significantly less impairment of FMD at 12 weeks (odds ratio 0.32, 95% CI 0.13-0.80, P = 0.014). The absolute treatment effect of isoflavone on brachial FMD was inversely related to baseline FMD (r = -0.51, P < 0.001), suggesting that vasoprotective effect of isoflavone was more pronounced in patients with more severe endothelial dysfunction. Moreover, isoflavone treatment for 12 weeks resulted in a significant decrease in serum high-sensitivity (hs)-C-reactive protein level (treatment effect -1.7 mg/L, 95% CI -3.3 to -0.1, P = 0.033). Nevertheless, isoflavone did not have any significant treatment effects on nitroglycerin-mediated dilatation, blood pressure, heart rate, serum levels of fasting glucose and insulin, haemoglobin A1c, and oxidative stress as determined by serum superoxide dismutase, 8-isoprostane, and malondialdehyde (all P > 0.05). CONCLUSION: This study demonstrated that 12 week isoflavone treatment reduced serum hs-C-reactive protein and improved brachial FMD in patients with clinically manifest atherosclerosis, thus reversing their endothelial dysfunction status. These findings may have important implication for the use of isoflavone for secondary prevention in patients with cardiovascular disease, on top of conventional interventions.

Acacetin, a natural flavone, selectively inhibits human atrial repolarization potassium currents and prevents atrial fibrillation in dogs.

BACKGROUND: The development of atrium-selective antiarrhythmic agents is a current strategy for inhibiting atrial fibrillation (AF). The present study investigated whether the natural flavone acacetin from the traditional Chinese medicine Xuelianhua would be an atrium-selective anti-AF agent. METHODS AND RESULTS: The effects of acacetin on human atrial ultrarapid delayed rectifier K(+) current (I(Kur)) and other cardiac ionic currents were studied with a whole-cell patch technique. Acacetin suppressed I(Kur) and the transient outward K(+) current (IC(50) 3.2 and 9.2 mumol/L, respectively) and prolonged action potential duration in human atrial myocytes. The compound blocked the acetylcholine-activated K(+) current; however, it had no effect on the Na(+) current, L-type Ca(2+) current, or inward-rectifier K(+) current in guinea pig cardiac myocytes. Although acacetin caused a weak reduction in the hERG and hKCNQ1/hKCNE1 channels stably expressed in HEK 293 cells, it did not prolong the corrected QT interval in rabbit hearts. In anesthetized dogs, acacetin (5 mg/kg) prolonged the atrial effective refractory period in both the right and left atria 1 to 4 hours after intraduodenal administration without prolongation of the corrected QT interval, whereas sotalol at 5 mg/kg prolonged both the atrial effective refractory period and the corrected QT interval. Acacetin prevented AF induction at doses of 2.5 mg/kg (50%), 5 mg/kg (85.7%), and 10 mg/kg (85.7%). Sotalol 5 mg/kg also prevented AF induction (60%). CONCLUSIONS: The present study demonstrates that the natural compound acacetin is an atrium-selective agent that prolongs the atrial effective refractory period without prolonging the corrected QT interval and effectively prevents AF in anesthetized dogs after intraduodenal administration. These results indicate that oral acacetin is a promising atrium-selective agent for the treatment of AF.