Establishment of a lipid metabolism disorder model in ApoEb mutant zebrafish

BACKGROUND AND AIMS

ApoEb is a zebrafish homologous to mammalian ApoE, whose deficiency would lead to lipid metabolism disorders (LMDs) like atherosclerosis. We attempted to knock out the zebrafish ApoEb, then establish a zebrafish model with LMD.

METHODS

ApoEb was knocked out using the CRISPR/Cas9 system, and the accumulation of lipids was confirmed by Oil Red O staining, confocal imaging, and lipid measurements. The lipid-lowering effects of simvastatin (SIM), ezetimibe (EZE) and Xuezhikang (XZK), an extract derived from red yeast rice, were evaluated through in vivo imaging in zebrafish larvae.

RESULTS

In the ApoEb mutant, significant vascular lipid deposition occurred, and lipid measurement performed in the whole-body homogenate of larvae and adult plasma showed significantly increased lipid levels. SIM, EZE and XZK apparently relieved hyperlipidemia in ApoEb mutants, and XZK had a significant inhibitory effect on the recruitment of neutrophils and macrophages.

CONCLUSIONS

In this study, an LMD model has been established in ApoEb mutant zebrafish. We suggest that this versatile model could be applied in studying hypercholesterolemia and related vascular pathology in the context of early atherosclerosis, as well as the physiological function of ApoE.

The Application and Teaching Value of a Ventricular Septal Defect Canine Model Established by Transcatheter Puncture

This study aimed to improve and further explore a ventricular septal defect (VSD) canine model on the basis of the transcatheter puncture method and to evaluate its application and teaching value.In order to lessen the complications of VSD closure, it is necessary to improve the currently available treatment devices using appropriate animal models.In this study, we used 16 healthy adult canines as our models. After anesthesia, the VSD puncture was performed, followed by balloon dilatation of the perforation. VSD was confirmed by angiography. The venous-artery orbit was established, and the VSD was then closed once the catheter and occluder were across the defect.Of the experimental canines, 14 of the 16 canines were successfully modeled, giving a success rate of 87.5%. The canines underwent an immediate creation of a venous-artery orbit for teaching practice and were implanted with an occluder during the procedure. After 4 weeks, 13 canines survived. As per our findings, most VSD types established by the puncture were perimembranous (10 of 13, 77%).The current model has a high success rate. The model can not only avoid the risk of infection and hemodynamic disorders associated with an open thoracotomy, but can also be effectively used in evaluating the impact of occluders. It can also directly measure the parameters of the devices during the procedure, thus having a very high experimental and teaching value.

Zfp36l1b protects angiogenesis through Notch1b/Dll4 and Vegfa regulation in zebrafish

BACKGROUND AND AIMS

Angiogenesis is a key process for establishing functional vasculature during embryogenesis and involves different signaling mechanisms. The RNA binding protein Zfp36l1 was reported to be involved in various diseases in different species, including cardiovascular diseases. However, whether Zfp36l1b, one of the 2 paralogs of Zfp36l1 in zebrafish, works like mammalian Zfp36l1, and if the molecular mechanisms are different remains unclear. Here, we show that Zfp36l1b plays a crucial protective role in angiogenesis of zebrafish embryos.

METHODS

We used transparent transgenic and wild-type zebrafish larvae to dynamically investigate the early stage of angiogenesis with confocal in vivo, after the knockdown of Zfp36l1b by morpholinos (MOs). In situ hybridization and fluorescence-activated cell sorting were performed to detect Zfp36l1b expression. mRNA rescue and CRISPR/Cas9 knockdown, and luciferase reporter experiments were performed to further explore the role of Zfp36l1b in angiogenesis.

RESULTS

We found that knockdown of Zfp36l1b led to defected angiogenesis in intersomitic vessels and sub-intestinal veins (SIVs), which could be rescued by the addition of Zfp36l1b mRNA. Moreover, knockdown of Zfp36l1b suppressed Notch1b expression, while knockdown of Notch1b resulted in a partial relief of angiogenesis defects induced by Zfp36l1b down-regulation. Besides, Zfp36l1b knockdown alleviated the excessive branch of SIVs caused by Vegfa over-expression.

CONCLUSIONS

Our results show that Zfp36l1b is responsible for establishing normal vessel circuits by affecting the extension of endothelial tip cells filopodia and the proliferation of endothelial cells partly through Notch1b/Fll4 suppression and synergistic function with Vegfa.

Percutaneous occlusion of transseptal puncture-related free wall perforation at the coronary sinus with a ventricular septal occluder during left atrial appendage closure: A case report

Coronary sinus perforation is a life-threatening complication of transseptal puncture and needs to be repaired immediately. In this study, we report a case of a 74-year-old female patient with nonvalvular atrial fibrillation, who is a poor long-term anticoagulation candidate. During the manipulation of transseptal puncture, a perforation of the free right atrial wall at the coronary sinus ostium occurred, which was caused by the Brockenbrough needle and followed by the immediate advancement of an 8.5-French transseptal sheath. In consideration of the danger of cardiac tamponade after sheath removal, we decided to leave the 8.5-French sheath in the pericardial cavity. Then, we advanced a 6 mm ventricular septal occluder through the sheath. Finally, we achieved successful deployment of the device and closure of the perforation under the guidance of fluoroscopy and transthoracic echocardiography. Subsequently, the left atrial appendage orifice was occluded with a 21 mm Watchman device. This case illustrates that percutaneous device closure is feasible for inadvertent perforation of the free right atrial wall at the coronary sinus during transseptal puncture and should be considered as an alternative to surgery.

[Expression profiles of microRNA related to atherosclerosis in patients with OSA]

Objective:Recent studies have demonstrated that obstructive sleep apnoea(OSA) may lead to atherosclerosis(AS), but the underlying mechanism remains unclear. MicroRNA(miRNA) may be involved in the gene regulation of AS and also in the occurrence and progression of OSA. The purpose of our study was to investigate the expression of atherosclerosis related serum miRNAs in OSA patients.Method: We screened 116 participants including normal controls(n=24), OSA alone(n=32),OSA patients with AS(n=32),and patients with AS but without OSA(n=28).qRT-PCR to analyze the microRNA profile was performed in these subjects.Clinical and blood test with lipid parameters were analysed using Spearman correlations.Result:Compared to normal controls, miRNA-148a-5p, miRNA-378c, miRNA-127-3p and miRNA-365a-3p were upregulated in the OSA, OSA-AS, and AS groups; miRNA-134-5p was only upregulated in the AS group, miRNA-365a-3p in the OSA-AS group was higher than that in the OSA alone group. The circulating atherosclerosis related miRNAs, including miRNA-148a-5p, miRNA-378c, miRNA-127-3p, miRNA-134-5p and miRNA-365a-3p all correlated with the carotid intima media thickness. Conclusion: Upregulation of miRNA-148a-5p, miRNA-365a-3p, miRNA-378c, miRNA-127-3p may be an early warning marker of atherosclerosis in OSA patients.

Rapamycin and CHIR99021 Coordinate Robust Cardiomyocyte Differentiation From Human Pluripotent Stem Cells Via Reducing p53-Dependent Apoptosis

Background

Cardiomyocytes differentiated from human pluripotent stem cells can serve as an unexhausted source for a cellular cardiac disease model. Although small molecule–mediated cardiomyocyte differentiation methods have been established, the differentiation efficiency is relatively unsatisfactory in multiple lines due to line‐to‐line variation. Additionally, hurdles including line‐specific low expression of endogenous growth factors and the high apoptotic tendency of human pluripotent stem cells also need to be overcome to establish robust and efficient cardiomyocyte differentiation.

Methods and Results

We used the H9–human cardiac troponin T–eGFP reporter cell line to screen for small molecules that promote cardiac differentiation in a monolayer‐based and growth factor–free differentiation model. We found that collaterally treating human pluripotent stem cells with rapamycin and CHIR99021 during the initial stage was essential for efficient and reliable cardiomyocyte differentiation. Moreover, this method maintained consistency in efficiency across different human embryonic stem cell and human induced pluripotent stem cell lines without specifically optimizing multiple parameters (the efficiency in H7, H9, and UQ1 human induced pluripotent stem cells is 98.3%, 93.3%, and 90.6%, respectively). This combination also increased the yield of cardiomyocytes (1:24) and at the same time reduced medium consumption by about 50% when compared with the previous protocols. Further analysis indicated that inhibition of the mammalian target of rapamycin allows efficient cardiomyocyte differentiation through overcoming p53‐dependent apoptosis of human pluripotent stem cells during high‐density monolayer culture via blunting p53 translation and mitochondrial reactive oxygen species production.

Conclusions

We have demonstrated that mammalian target of rapamycin exerts a stage‐specific and multifaceted regulation over cardiac differentiation and provides an optimized approach for generating large numbers of functional cardiomyocytes for disease modeling and in vitro drug screening.

MicroRNA-199a acts as a potential suppressor of cardiomyocyte autophagy through targeting Hspa5

Autophagy is an adaptive response to cardiomyocytes survival under stress conditions. MicroRNAs (miRNAs, miR) have been described to act as potent modulators of autophagy. To investigate whether and how miR-199a modulated autophagy in vitro, primary cardiomyocytes were treated under starvation to induce autophagy. Results showed that down-regulation of miR-199a was sufficient to activate cardiomyocytes autophagy. MiR-199a suppressed cardiomyocytes autophagy through direct inhibiting heat shock protein family A member 5 (Hspa5). Forced overexpression of Hspa5 recovered the inhibitory effect of miR-199a in autophagy activation. Our results suggested miR-199a as an effective suppressor of starvation-induced cardiomyocytes autophagy and that Hspa5 was a direct target during this process. These results extend the understanding of the role and pathway of miR-199a in cardiomyocytes autophagy, and may introduce a potential therapeutic strategy for the protection of cardiomyocytes in myocardial infarction or ischemic heart disease.

[Clinical analysis of 24 cases of aortic dissection during pregnancy]

Objective: To investigate the management and perinatal outcome of aortic dissection during pregnancy. Methods: 24 pregnant women with aortic dissection who delivered in Beijing Anzhen Hospital Affiliated to Capital Medical University from January 1st, 2006 to February 29th, 2016 were recruited. The clinical data, the management and the perinatal outcome were analyzed retrospectively. Results: (1) Clinical features: The average age of the patients was (29±4) years old. The clinical symptoms occurred from 5 gestational weeks to 1 month after delivery. The major symptoms were chest pain, and some complained migratory or radiating pains. There were 17 Stanford type A cases and 7 type B cases. The aortic widths were 2.9-10.0 cm, with the average of (5.6±1.7) cm. D-dimer level was 448-6 421 μg/L, with the average of (1 097±1 209) μg/L, and the fibrin degradation products were 4.1-52.1 mg/L, with the average of (10.2±9.5) mg/L.The white blood cell ranged (6.8-36.4)×10(9)/L, with the average of (29.4±4.2)×10(9)/L; and the neutrophil rate was 76.0%-97.6%, with the average of (84.6±6.3) %. (2) The treatment: ①19 patients underwent aorta surgeries. The surgeries included aortic root replacement with total aortic arch replacement plus stented elephant trunk implantation (Bentall+Sun's surgery), aortic root replacement (Bentall surgery), stent implantation, thoracic and abdominal aorta replacement. The aortic operation time of the 19 patients were 5 gestational weeks to 1 month after delivery. The relation between aortic operation and the termination of pregnancy: 4 patients underwent aorta surgery after termination of pregnancy, 9 patients had cesarean section and aorta surgery at the same time, 6 patients underwent aorta surgery before cesarean section. ② 5 patients did not receive arota surgery, 2 patients of type A dissection and 1 patient of type B dissection died before the surgery; 2 cases of type B dissection underwent conservative treatment. The termination time of pregnancy was 6-37 gestational weeks, with the average of (26±10) weeks. (3)Maternal and fetal outcomes: 20 patients survived after treatment (83%, 20/24) and 4 patients died (17%, 4/24). 10 cases were live births, including 4 full-term infants and 6 preterm premature infants. The birth weight of the neonates was 1 080-3 800 g, with the average of (2 302±764) g. Three of them were very low birth weight infants and 1 was low birth weight infant; 3 neonates had mild asphyxia. The neonates were followed up for 0.5 to 10 years, with the average time of (1.4±1.7) years. So far the infants' development was good. Conclusions: Pregnancy with aortic dissection is pernicious. Early identification, prompt diagnosis and prompt interventing of the vascular surgery are necessary to the safety of mother and fetus.

Transcatheter Closure of Perimembranous Ventricular Septal Defects Using Dual Wire-Maintaining Technique

OBJECTIVE

The present study was designed to evaluate the safety and feasibility of transcatheter closure of perimembranous ventricular septal defects (PmVSDs) with dual wire-maintaining technique (DWMT).

PATIENTS/METHODS

From January 2010 to December 2013, a total of 241 patients (men: 109, women: 132; mean age: 22.2±15.4 years) with congenital PmVSDs were randomised to either the conventional technique (CT) group (n=118) or the DWMT group (n=123).

RESULTS

In the CT group, the track wire was withdrawn before occluder insertion. In the DWMT group, the track wire was maintained in the delivery sheath during the procedure. Both the procedure time and fluoroscope time were reduced significantly in the DWMT group patients who required device replacement compared with CT group patients (median time: 46.0±14.8min vs. 56.0±15.2min, p<0.05; 15.0±11.6min vs. 22.0±10.1min, p<0.05). There was no difference in the incidence of complications between the two groups.

CONCLUSION

The DWMT is safe and feasible for transcatheter treatment of PmVSDs, especially in patients requiring device replacement, for it avoids reconstruction of the "arteriovenous wire loop", left ventriculography from the contralateral femoral route, or the use of a larger femoral artery short sheath.

MicroRNA-126a Directs Lymphangiogenesis Through Interacting With Chemokine and Flt4 Signaling in Zebrafish

OBJECTIVE

MicroRNA-126 (miR-126) is an endothelium-enriched miRNA and functions in vascular integrity and angiogenesis. The application of miRNA as potential biomarker and therapy target has been widely investigated in various pathological processes. However, its role in lymphatic diseases had not been widely explored. We aimed to reveal the role of miR-126 in lymphangiogenesis and the regulatory signaling pathways for potential targets of therapy.

APPROACH AND RESULTS

Loss-of-function studies using morpholino oligonucleotides and CRISPR/Cas9 (clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 9) system showed that silencing of miR-126a severely affected the formation of parachordal lymphangioblasts and thoracic duct in zebrafish embryos, although their development in miR-126b knockdown embryos was normal. Expression analyses by in situ hybridization and immunofluorescence indicated that miR-126a was expressed in lymphatic vessels, as well as in blood vessels. Time-lapse confocal imaging assay further revealed that knockdown of miR-126a blocked both lymphangiogenic sprouts budding from the posterior cardinal vein and lymphangioblasts extension along horizontal myoseptum. Bioinformatics analysis and in vivo report assay identified that miR-126a upregulated Cxcl12a by targeting its 5' untranslated region. Moreover, loss- and gain-of-function studies revealed that Cxcl12a signaling acted downstream of miR-126a during parachordal lymphangioblast extension, whereby Flt4 signaling acts as a cooperator of miR-126a, allowing it to modulate lymphangiogenic sprout formation.

CONCLUSIONS

These findings demonstrate that miR-126a directs lymphatic endothelial cell sprouting and extension by interacting with Cxcl12a-mediated chemokine signaling and Vegfc-Flt4 signal axis. Our results suggest that these key regulators of lymphangiogenesis may be involved in lymphatic pathogenesis of cardiovascular diseases.

Forkhead containing transcription factor Albino controls tetrapyrrole-based body pigmentation in planarian

Pigmentation processes occur from invertebrates to mammals. Owing to the complexity of the pigmentary system, in vivo animal models for pigmentation study are limited. Planarians are capable of regenerating any missing part including the dark-brown pigments, providing a promising model for pigmentation study. However, the molecular mechanism of planarian body pigmentation is poorly understood. We found in an RNA interference screen that a forkhead containing transcription factor, Albino, was required for pigmentation without affecting survival or other regeneration processes. In addition, the body color recovered after termination of Albino double stranded RNA feeding owing to the robust stem cell system. Further expression analysis revealed a spatial and temporal correlation between Albino and pigmentation process. Gene expression arrays revealed that the expression of three tetrapyrrole biosynthesis enzymes, ALAD, ALAS and PBGD, was impaired upon Albino RNA interference. RNA interference of PBGD led to a similar albinism phenotype caused by Albino RNA interference. Moreover, PBGD was specifically expressed in pigment cells and can serve as a pigment cell molecular marker. Our results revealed that Albino controls planarian body color pigmentation dominantly via regulating tetrapyrrole biogenesis. These results identified Albino as the key regulator of the tetrapyrrole-based planarian body pigmentation, suggesting a role of Albino during stem cell-pigment cell fate decision and provided new insights into porphyria pathogenesis.

Transcatheter closure of atrial septal defects improves cardiac remodeling and function of adult patients with permanent atrial fibrillation

Background:

Permanent atrial fibrillation (AF) is the most common form of dysrhythmia associated with atrial septal defects (ASDs) in patients older than 40 years. However, little is known about cardiac remodeling after transcatheter closure in patients with permanent AF. This study was designed to compare cardiac events and remodeling effects after transcatheter closure in such patients.

Methods:

Clinical data of 289 adult patients older than 40 years who underwent ASD closure at our center were analyzed retrospectively. Of them, 63 patients with permanent AF were assigned to the case group, and the other 226 patients without permanent AF were assigned to the control group. Cardiac events and changes in left and right cardiac cavity dimensions before the procedure and 6 months after the procedure were compared between the two groups.

Results:

Patients in the case group were significantly older than those in the control group. The right ventricular (RV) volume and right atrial (RA) volume were decreased significantly in both the groups during a median follow-up period of 6 months after closure (P < 0.001). The left atrial dimensions, left ventricular end-systolic dimensions, left ventricular end-diastolic dimensions and left ventricular ejection fraction showed no significant change before and after the procedure in both the groups. Changes of the RV volume and RA volume in the case group were significantly smaller than those in the control group (P = 0.005 and P < 0.001). The New York Heart Association cardiac function was improved in both the groups during the 6 months follow-up period.

Conclusions:

The transcatheter closure of ASD can improve the cardiac remodeling and cardiac function in patients with or without AF.

Percutaneous Closure of Perimembranous Ventricular Septal Defect with Modified Double-disk Occluder: What Is the Outcome at 10-year Follow-up?

OBJECTIVE

Percutaneous closure of perimembranous ventricular septal defect is one of the greatest challenges in interventional cardiology. The long-term follow-up data are still limited. This report presents our experience in percutaneous closure of perimembranous ventricular septal defect with modified double-disk occluder.

DESIGN

The study is a retrospective analysis of cases from the Changhai Hospital clinic database.

SETTING

We reviewed the clinic database from December 2001 to December 2005.

PATIENTS

We included 117 patients who underwent percutaneous closure of perimembranous ventricular septal defects.

OUTCOME MEASURES

Procedural data and complications were assessed by an expert panel of cardiologists.

RESULTS

Device implantation was successfully accomplished in 113 of a total 117 patients (96.6%). The mean age was 31.1 ± 12.5 years (range 2-56 years). The patients were followed for a period of 86-134 months. The diameter of defect was 2-15 mm (mean 4.9 ± 2.9 mm). The ventricular septal defect rim below the aortic valve was 1-5 mm. The mean diameter of device used was 6.9 ± 3.7 (range 4-24 mm). Four patients presented complete atrio-ventricular block within 1 week after the procedure and recovered within 3 weeks. No other patient encountered serious adverse events during the follow-up.

CONCLUSIONS

Percutaneous closure of ventricular septal defect is safe and effective in most selected patients with modified double-disk occluder. Additional studies with larger cohorts and longer follow-up are needed to evaluate its safety.

Balloon-expanding stent and delivery system for transcatheter aortic valve implantation: An animal study

OBJECTIVE

To evaluate the feasibility and satefy of transcatheter aortic valve implantation in animals by using a new balloon-expanding valved stent.

METHODS

The balloon-expandable stent is made from cobalt-based alloy material and designed with a tubular, slotted structure. Fresh bovine pericardium was treated, sutured and fixed on the balloon-expandable stent. Ten healthy sheep (five males and five females), weighing an average of (25.16 ± 1.83) kg, were selected to undergo transcatheter implantation of the valve stents. The function of the valve stent was evaluated by angiography, echocardiography, and histology six months after the procedure.

RESULTS

Of the ten experimental sheep, two sheep died during the operation because the higher position of the artificial valve affected the opening of the coronary artery. We successfully implanted the aortic valve stent in other eight sheep; however, one sheep died of heart failure two weeks after the operation due to the lower position of the valve stent. The valve stents were implanted in the desired position in seven sheep. Ascending aortic angiographic and autoptic findings immediately after the operation confirmed the satisfactory location and function of the valved stent. Echocardiography, angiography, and histology at six postoperative months confirmed the satisfactory location and function of the valve stent.

CONCLUSION

We successfully implanted our new valve stent as a replacement of native aortic valve via the transcatheter route with satisfactory outcome.

Transcatheter aortic valve implantation assisted with microcatheter: a new method to avoid coronary artery obstruction

Background:

Lack of fluoroscopic landmarks can make valve deployment more difficult in patients with absent aortic valve (AV) calcification. The goal of this article was to evaluate the feasibility and effectiveness of transcatheter implantation of a valved stent into the AV position of a goat, assisted with a microcatheter which provides accurate positioning of coronary artery ostia to help valved stent deployment.

Methods:

The subjects were 10 healthy goats in this study. A microcatheter was introduced into the distal site of right coronary artery (RCA) through femoral artery sheath. A minimal thoracic surgery approach was used to access the apex of the heart. The apex of the left ventricle was punctured; a delivery catheter equipped with the valved stent was introduced over a stiff guidewire into the aorta arch. We could accurately locate the RCA ostia through the microcatheter placed in the RCA under fluoroscopy. After correct valve position was confirmed, the valved stent was implanted after rapid inflation of the balloon. The immediate outcome of the function of the valved stents was evaluated after implantation.

Results:

All ten devices were successfully implanted into the AV position of the goats. Immediate observation after the procedure showed that the valved stents were in the desired position after implantation by angiography, echocardiogram. No obstruction of coronary artery ostia occurred, and no moderate to severe aortic regurgitation was observed.

Conclusions:

When the procedure of transcatheter implantation of a balloon-expandable valved stent into the AV position of goats is assisted with microcatheter positioning coronary artery ostia, the success rate of operation can be increased in those with noncalcified AV.

Simultaneous transcatheter treatment of perimembranous ventricular septal defect and other congenital cardiopathies

OBJECTIVE

To assess the efficacy and safety of simultaneous transcatheter corrections of perimembranous ventricular septal defect (VSD) and other congenital cardiopathies.

PATIENTS/METHODS

From 2004 to 2012, 56 patients (25 male, 31 female), aged 14.2±10.1, with compound congenital cardiovascular abnormalities underwent simultaneous transcatheter interventional procedure. Of the 56 patients, 32 had VSD and atrial septal defects (ASD); 17 had VSD and patent ductus arteriosus (PDA); and seven had VSD and pulmonary valve stenosis (PS). Percutaneous balloon pulmonary valvuloplasty (PBPV) was performed before the closure of VSD, PDA, or ASD.

RESULTS

The combined transcatheter interventional procedure was successfully performed in all patients. Among these, two occluders were implanted in each of 49 patients, seven patients with VSD combined with PS underwent successfully balloon valvuloplasty and VSD closure. The size of VSD, ASD and PDA detected by TTE was 4.8±1.7 mm, 9.0±5.0 mm and 4.5±2.5 mm, respectively. The occluder diameter of VSD, ASD and PDA was 7.6±2.2 mm, 14.3±6.2 mm and 7.9±3.2 mm, respectively. The peak-to-peak transpulmonary gradient decreased from 60.4±19.7 mmHg to 15.0±5.0 mmHg (p<0.001) in seven patients with VSD combined with PS. One patient with VSD and ASD had a permanent pacemaker implanted because of third-degree atrioventricular block two months after the procedure. There were not serious adverse events in relation to the combined procedures during the 23.8±20.7 months of follow-up in other 55 patients.

CONCLUSION

The simultaneous treatment of VSD and other congenital cardiopathies using transcatheter-based procedures is safe and effective, which can provide satisfactory results.

Elevated microRNA-155 promotes foam cell formation by targeting HBP1 in atherogenesis

AIM

MicroRNAs (miRNAs) play key roles in inflammatory responses of macrophages. However, the function of miRNAs in macrophage-derived foam cell formation is unclear. Here, we investigated the role of miRNAs in macrophage-derived foam cell formation and atherosclerotic development.

METHODS AND RESULTS

Using quantitative reverse transcription-PCR (qRT-PCR), we found that the level of miR-155 expression was increased significantly in both plasma and macrophages from atherosclerosis (ApoE(-/-)) mice. We identified that oxidized low density lipoprotein (oxLDL) induced the expression and release of miR-155 in macrophages, and that miR-155 was required to mediate oxLDL-induced lipid uptake and reactive oxygen species (ROS) production of macrophages. Furthermore, ectopic overexpression and knockdown experiments identified that HMG box-transcription protein1 (HBP1) is a novel target of miR-155. Knockdown of HBP1 enhanced lipid uptake and ROS production in oxLDL-stimulated macrophages, and overexpression of HBP1 repressed these effects. Furthermore, bioinformatics analysis identified three YY1 binding sites in the promoter region of pri-miR-155 and verified YY1 binding directly to its promoter region. Detailed analysis showed that the YY1/HDAC2/4 complex negatively regulated the expression of miR-155 to suppress oxLDL-induced foam cell formation. Importantly, inhibition of miR-155 by a systemically delivered antagomiR-155 decreased clearly lipid-loading in macrophages and reduced atherosclerotic plaques in ApoE(-/-) mice. Moreover, we observed that the level of miR-155 expression was up-regulated in CD14(+) monocytes from patients with coronary heart disease.

CONCLUSION

Our findings reveal a new regulatory pathway of YY1/HDACs/miR-155/HBP1 in macrophage-derived foam cell formation during early atherogenesis and suggest that miR-155 is a potential therapeutic target for atherosclerosis.

Overexpression of G100S mutation in PRKAG2 causes Wolff-Parkinson-White syndrome in zebrafish

The Wolff-Parkinson-White (WPW) syndrome was believed to be associated with PRKAG2 gene mutations. In this study, we verified the pathopoiesis of G100S mutation, a novel mutation only discovered in Chinese patients with WPW, in cardiac disorder. Similar to R302Q, when overexpressed PRKAG2 G100S mutant in zebrafish, we observed a thicker heart wall, detected a decreased AMPK enzymatic activity by tissue AMPK kinase activity colorimetric technique, as well as examined an increased glycogen storage in heart wall using the method for periodic acid-Schiff staining, in comparison with the zebrafish without exogenous PRKAG2 (mock) or with wild-type PRKAG2 (WT). Taken together, we concluded PRKAG2 G100S mutation might contribute to impair the AMP-activated protein kinase function, which resulted in increased cardiac glycogen storage, serving as a pathogenesis for WPW syndrome in Chinese.

Percutaneous valved stent implantation in the ascending aorta for the treatment of very high-risk aortic regurgitation: an animal study

PURPOSE

We investigated the effects of percutaneous valved stent implantation in the ascending aorta as an alternative treatment for aortic regurgitation in a canine model.

MATERIALS AND METHODS

A total of 16 healthy dogs weighing an average of 18.3 ± 2.1 kg were used for the establishment of animal models of chronic aortic regurgitation by percutaneous aortic valve perforation and balloon dilation. At 2 mo after successful model establishment, all experimental animals underwent valved stent implantation in the ascending aorta and then were followed up for 3 mo.

RESULTS

Experimental models of chronic aortic regurgitation were successfully established in 10 dogs. Surviving dogs underwent successful valved stent implantation in the ascending aorta and were subsequently followed up for 3 mo. The level of instantaneous aortic regurgitation at 3-mo follow-up was significantly reduced compared with that before valved stent implantation (2.4 ± 0.9 versus 10.6 ± 2.1 mL/s, P < 0.05). The left ventricular ejection fraction was significantly increased (53.8 ± 4.2% versus 37.8 ± 3.7%, P < 0.05), and the left ventricular end-diastolic volume was also significantly reduced (30.3 ± 2.2 versus 40.1 ± 3.6 mL, P < 0.05). No paravalvular leak, stroke, atrioventricular block, or other complications occurred in dogs undergoing valved stent implantation.

CONCLUSIONS

Percutaneous valved stent implantation in the ascending aorta is feasible, effective, and safe as an alternative treatment for very high-risk aortic regurgitation in a canine model.

Heterochromatin protein 1 promotes self-renewal and triggers regenerative proliferation in adult stem cells

Adult stem cells (ASCs) capable of self-renewal and differentiation confer the potential of tissues to regenerate damaged parts. Epigenetic regulation is essential for driving cell fate decisions by rapidly and reversibly modulating gene expression programs. However, it remains unclear how epigenetic factors elicit ASC-driven regeneration. In this paper, we report that an RNA interference screen against 205 chromatin regulators identified 12 proteins essential for ASC function and regeneration in planarians. Surprisingly, the HP1-like protein SMED-HP1-1 (HP1-1) specifically marked self-renewing, pluripotent ASCs, and HP1-1 depletion abrogated self-renewal and promoted differentiation. Upon injury, HP1-1 expression increased and elicited increased ASC expression of Mcm5 through functional association with the FACT (facilitates chromatin transcription) complex, which consequently triggered proliferation of ASCs and initiated blastema formation. Our observations uncover an epigenetic network underlying ASC regulation in planarians and reveal that an HP1 protein is a key chromatin factor controlling stem cell function. These results provide important insights into how epigenetic mechanisms orchestrate stem cell responses during tissue regeneration.

Activation of receptor for advanced glycation end products contributes to aortic remodeling and endothelial dysfunction in sinoaortic denervated rats

OBJECTIVE

The aim of present study was to test the hypothesis that activation of receptor for advanced glycation end products (RAGE) pathway contributes to aortic remodeling and endothelial dysfunction in sinoaortic denervated (SAD) rats.

METHODS AND RESULTS

Experiment 1: 8 weeks after sinoaortic denervation, aortas were removed for measurement of AGE/RAGE pathway. Sinoaortic denervation in rats resulted in enhanced activity of aldose reductase, reduced activity of glyoxalase 1, accumulation of methylglyoxal and AGE, and upregulated expression of RAGE in aortas. Experiment 2: 5 weeks after sinoaortic denervation, the rats received intraperitoneal injections of 500 μg soluble RAGE (sRAGE) daily for 3 weeks. Treatment of SAD rats with sRAGE attenuated aortic remodeling, marked by reduction in AW/length, wall thickness, proliferation of SMC, and collagen deposition, and improvement of endothelial function. Treatment of SAD rats with sRAGE abated aortic oxidative stress, marked by reduction in formation of malondialdehyde, reactive oxygen species, superoxide, peroxynitrite and 3-nitrotyrosine, and enhancement of ratio of GSH/GSSG. Treatment of SAD rats with sRAGE attenuated aortic mitochondrial dysfunction. Treatment of SAD rats with sRAGE suppressed aortic NFκB nuclear translocation and inflammation. Treatment of SAD rats with sRAGE restored aortic NO formation through upregulating eNOS and dimethylarginine dimethylaminohydrolase-2 and downregulating protein arginine methyltransferase-1.

CONCLUSION

Activated RAGE contributed to aortic remodeling and endothelial dysfunction in SAD rats, possibly via induction of oxidative stress and inflammation, impairment of mitochondrial function, and reduction in NO bioavailability.

Naloxone inhibition of lipopolysaccharide-induced activation of retinal microglia is partly mediated via the p38 mitogen activated protein kinase signalling pathway

OBJECTIVES

To investigate the effects and underlying mechanism of action of naloxone on lipopolysaccharide (LPS)-induced activation of retinal microglia in vitro.

METHODS

Rat retinal microglia primary cultures were divided into four treatment groups: untreated; 1 μg/ml LPS for 12 h; 0.5, 1.0 or 2.0 μM naloxone for 30 min before LPS; 2.5 or 5.0 μM SB203580 for 12 h before LPS and naloxone. Levels of tumour necrosis factor (TNF)-α and interleukin (IL)-1β were determined by enzyme-linked immuno sorbent assay. Western blot analysis and double immunofluorescence were used to examine activation of the mitogen activated protein kinase (MAPK) signalling pathway.

RESULTS

LPS induced an increase in TNF-α and IL-1β in culture supernatants, which was dose-dependently inhibited by naloxone. Naloxone also dose-dependently inhibited LPS-induced increases in phosphorylated p38 MAPK. Pretreatment of cells with SB203580 attenuated the inhibitory effect of naloxone on TNF-α and IL-1β production.

CONCLUSIONS

Naloxone suppressed LPS-induced activation of cultured retinal microglia and this suppression appeared to occur partly through the p38 MAPK signalling pathway. Naloxone may have therapeutic potential in neuro degenerative diseases characterized by the activation of microglia.

MicroRNA degradation and turnover: regulating the regulators

MicroRNAs (miRNAs) are endogenous, small noncoding RNAs that play important regulatory roles in gene expression. The control of miRNA biogenesis has been well characterized, but their degradation is not fully understood. Recent discoveries indicate that miRNAs have a long life span in general. However, rapid turnover dynamics of miRNAs in a variety of specific cellular contexts has been documented, as well as the requirement of sequence elements for miRNA decay. Furthermore, several ribonucleases that degrade miRNAs have been identified. Here, we discuss the cellular contexts and biochemical mechanisms of miRNA decay, together with several prominent questions in this field.

Attenuation of microRNA-22 derepressed PTEN to effectively protect rat cardiomyocytes from hypertrophy

Cardiac hypertrophy, which is characterized by the enlargement of cell size, reactivation of fetal genes, remains one of the most important triggers to heart failure. Increasing evidence shows that microRNA (miRNA) is extensively involved in the pathogenesis of cardiac hypertrophy. But the effects of miRNAs on cardiomyocyte hypertrophy have not been completely solved yet. Here, we showed that a collection of miRNAs was aberrantly expressed in hypertrophic cardiomyocytes induced by phenylephrine (PE) or angiotensin II (Ang II). Among them, miR-22 was the most strikingly up-regulated miRNA. To investigate the role of miR-22 in hypertrophy, both over-expression and knock-down assays were performed on cardiomyocytes. The results showed that up-regulation of miR-22 significantly increased the cell size and markedly influenced the expression of hypertrophic markers, including induction of nppa and reduction of myh6. In contrast, reduction of miR-22 level attenuated either PE- or Ang II-induced hypertrophic reaction. Furthermore, several genes, including PTEN, were identified as potential targets of miR-22 by bioinformatic algorithms. Using luciferase analysis, miR-22 could significantly suppress the luciferase activity of reporter fused with 3' untranslated region of PTEN mRNA. Furthermore, up-regulation of miR-22 could suppress the protein level of PTEN and reduction of miR-22 level markedly increased the protein level of PTEN in cardiomyocytes by Western blot analysis, suggesting that the contribution of miR-22 to cardiomyocyte hypertrophy may be partially through targeting PTEN. Taken together, miRNAs were dynamically regulated in cardiomyocyte hypertrophy and attenuation of miR-22 in rat cardiomyocytes efficiently protected from hypertrophic effects through derepressing PTEN.

Percutaneous valved stent implantation above the coronary ostia

BACKGROUND

In recent years, some experimental and clinical studies on transcatheter aortic valve implantation (TAVI) have been conducted. TAVI is indicated in patients with calcified pure or predominant aortic stenosis. The risk of this technique is still high. Aortic valved stent implantation above the coronary ostia might avoid blocking the coronary ostia.

METHODS AND RESULTS

Twenty healthy dogs were selected to establish a canine model of acute aortic valve rupture. The dogs were randomly divided into 2 groups: the rupture model group without any treatment and the valved stent group with percutaneous valved stent implantation above the coronary ostia. The 2 groups of animals were followed up for 3 months. Echocardiography and other tests were performed to assess aortic regurgitation and ventricular function. Acute aortic valve rupture models were successfully established in 16 of 20 dogs. In the rupture model group, the mean aortic regurgitation was 6.8 ± 1.9 ml/s; only 3 of 8 animals survived for 3 months. In the valved stent group, the mean aortic regurgitation was 7.0 ± 2.1 ml/s; valved stents were successfully implanted in 8 animals. Instant post-implantation anatomy showed that the stents were located appropriately. Seven dogs survived for 3 months.

CONCLUSIONS

Percutaneous valved stent implantation above the coronary ostia is feasible and effective as a transitional treatment for acute aortic valve rupture.

Uracils at nucleotide position 9-11 are required for the rapid turnover of miR-29 family

MicroRNAs are endogenous small RNA molecules that regulate gene expression. Although the biogenesis of microRNAs and their regulation have been thoroughly elucidated, the degradation of microRNAs has not been fully understood. Here by using the pulse–chase approach, we performed the direct measurement of microRNA lifespan. Five representative microRNAs demonstrated a general feature of relatively long lifespan. However, the decay dynamic varies considerably between these individual microRNAs. Mutation analysis of miR-29b sequence revealed that uracils at nucleotide position 9–11 are required for its rapid decay, in that both specific nucleotides and their position are critical. The effect of uracil-rich element on miR-29b decay dynamic occurs in duplex but not in single strand RNA. Moreover, analysis of published data on microRNA expression profile during development reveals that a substantial subset of microRNAs with the uracil-rich sequence tends to be down-regulated compared to those without the sequence. Among them, Northern blotting shows that miR-29c and fruit fly bantam possess a relatively rapid turnover rate. The effect of uracil-rich sequence on microRNA turnover depends on the sequence context. The present work indicates that microRNAs contain sequence information in the middle region besides the sequence element at both ends.

Vascular smooth muscle cell proliferation is influenced by let-7d microRNA and its interaction with KRAS

BACKGROUND

Several microRNAs (miRNAs) have been reported to regulate cardiovascular biological and pathological processes through inhibiting the translation of certain RNA transcripts. However, little is known about the association between miRNAs and vascular smooth muscle cell (VSMC) proliferation. The aim was to investigate the role of miRNAs in VSMC growth and the potential mechanism.

METHODS AND RESULTS

Primary VSMCs were isolated from the medial layer of the thoracic aorta obtained from spontaneously hypertensive rats (SHR) and Wistar Kyoto rats (WKY). miRNA microarrays were used to analyze the difference in miRNA expression between VSMCs of SHR and WKY rats and were validated using TaqMan real-time PCR. Of the potentially related genes under the influence of let-7d identified through literature search, KRAS was verified by western blot and functionally analyzed using miRNA mimics transfection and analysis of transfectants by cell enumeration was made using CCK-8 and flow cytometric analysis of cell cycle progression. let-7d-transfected VSMCs from SHR, WKY and human coronary arteries expressed significantly lower amounts of KRAS protein, displayed reduced cell growth and led to a greater number of cells in the G1 phase than the G2/M phases of the cell cycle.

CONCLUSIONS

let-7d was significantly downregulated in VSMCs as an important regulator of cell proliferation. RAS might be involved in the proliferation regulation by let-7d.

Transcatheter device closure of intracristal ventricular septal defects

Transcatheter closure of ventricular septal defects (VSDs) is now offered as primary therapy at many institutions. We sought to evaluate the clinical feasibility and safety of device closure of intracristal VSDs using perimembranous occluders. A total of 49 patients were diagnosed with intracristal VSDs and assigned to the intracristal VSD group, and another 49 patients with the same size perimembranous VSDs were selected and assigned to the perimembranous VSD group. Two types of perimembranous occluders, symmetric and asymmetric, were used, and no difference was found between the groups with respect to successful closure. The diameter of the intracristal VSD was 3 to 10 mm (mean 5.8 ± 1.4) on the transthoracic echocardiogram. The procedure time and fluoroscope time in the intracristal VSD group were significantly greater than those in the perimembranous VSD group. More defects with a subaortic rim ≤ 2 mm on the transthoracic echocardiogram were present in the intracristal VSD group than in the perimembranous VSD group; thus, more asymmetric occluders were used in the intracristal VSD group. All devices remained in a stable position and in an optimal shape during follow-up. In conclusion, transcatheter closure of intracristal VSDs with the perimembranous occluder is feasible, safe, and effective.

Symptomatic sinus tachycardia with perpetuating slow pathway: successful treatment with radiofrequency ablation

We report a case of sinus tachycardia with perpetuating slow pathway (SP) conduction in a 42-year-old woman who developed severe symptoms as a result of atrioventricular (AV) desynchronization. The restoration of an AV synchrony, achieved with selective radiofrequency ablation of the SP, eliminated the symptomatic arrhythmia and may represent a reasonable therapeutic option despite the fact that the patient has no AV-node reentrant tachycardia. This case demonstrates the importance of AV timing.

Percutaneous valve stent insertion to correct the pulmonary regurgitation: an animal feasibility study

BACKGROUND

Pulmonary regurgitation leads to progressive right ventricular dysfunction, susceptibility to arrhythmias, and sudden cardiac death. Percutaneous valve replacement has been developed in recent years, providing patients with an alternative option. Percutaneous pulmonary valve replacement has been recently introduced into clinical practice. The goal of this study was to evaluate the feasibility of percutaneous valve stent insertion to correct the pulmonary regurgitation in sheep using a cup-shaped valve stent.

METHODS

Pulmonary regurgitation was created by percutaneous cylindrical stent insertion in native pulmonary annulus of 8 sheep. One month after the initial procedure, the sheep with previous cylindrical stent implanted underwent the same implantation procedure of pulmonary valve stent. The valve stent consisted of a cup-shaped stent and pericardial valves. Hemodynamic assessments of the bioprosthetic pulmonary valve were obtained by echocardiography at immediately post-implant and at 2 months follow up.

RESULTS

Successful transcatheter cylindrical stent insertion was performed in 7 sheep but failed in 1 sheep because the cylindrical stent was released to right ventricle outflow tract. After one month the 7 sheep with pulmonary regurgitation underwent valve stent implantation successfully. Echocardiography confirmed the stents were in desired position during the follow-up. No evidence of pulmonary valve insufficiency occurred in any animals. Echocardiography showed all heart function markers were normal.

CONCLUSIONS

Percutaneous cylindrical stent insertion to induce significant pulmonary regurgitation in sheep was feasible, simple and reproducible. Percutaneous pulmonary valve stent implantation can reduce pulmonary regurgitation in a sheep model. Further development of animal model and clinical trials are warranted.

Early diagnosis and rescue pericardiocentesis for acute cardiac tamponade during radiofrequency ablation for arrhythmias. Is fluoroscopy enough?

BACKGROUND

With the number of complex catheter ablation procedures increasing, procedure-related acute cardiac tamponade is encountered more frequently in the cardiac catheterization laboratory. Survival depends on prompt recognition and rescue pericardiocentesis.

OBJECTIVE

The aim of this report was to validate fluoroscopic heart silhouette characteristics associated with cardiac tamponade as a diagnostic method, and evaluate the safety and effectiveness of fluoroscopy-guided pericardiocentesis during catheter ablation.

METHODS

All cases of acute cardiac tamponade that occurred in the cardiac catheterization laboratory during radiofrequency catheter ablation from March 2004 to November 2009 were reviewed retrospectively.

RESULTS

Of 1,832 catheter ablation procedures performed during a 5-year period, 10 (0.55%) were complicated by cardiac tamponade. Fluoroscopic examination confirmed the diagnosis in all 10 patients and demonstrated effusions before hypotension in four patients. All patients were stabilized by fluoroscopy-guided pericardiocentesis with placement of an indwelling catheter and autologous transfusion. The time interval between recognition of cardiac tamponade and completion of pericardiocentesis was 6.0 ± 1.8 minutes (range 3-9 minutes). The mean aspirated blood volume was 437 mL (range 110-1,400 mL), and the mean autotransfused blood volume was 425 mL (range 100-1,384 mL). Surgical repair of the cardiac perforation was needed in one patient. No procedure-related death occurred.

CONCLUSION

A reduction in the excursion of cardiac silhouette on fluoroscopy is an early diagnostic sign of cardiac tamponade during radiofrequency ablation. Fluoroscopy-guided pericardiocentesis is a safe and effective management strategy for cardiac tamponade developed in the cardiac catheterization laboratory.

MicroRNAs are dynamically regulated in hypertrophic hearts, and miR-199a is essential for the maintenance of cell size in cardiomyocytes

Cardiac hypertrophy, which is characterized by an increase in cell size and reactivation of fetal genes, occurs as an adaptive response to diverse forms of stress and often results in heart failure and sudden death. Growing evidence indicates that microRNAs (miRNAs) are involved in cardiac hypertrophy, but the function of these miRNAs remains elusive. Here, using real time PCR analysis, we showed that several miRNAs were dynamically regulated in the rat hypertrophic hearts and miR-199a was up-regulated by 10-fold in hypertrophic hearts after abdominal aorta constriction for 12 weeks. With tissue profiling analysis, we showed that miR-199a was predominantly expressed in cardiomyocytes, but was also faintly detected in cardiac fibroblasts. To investigate whether miR-199a was involved in cardiac hypertrophy, both over-expression and knockdown of miR-199a were performed in cultured cardiomyocytes. Over-expression of miR-199a in cardiomyocytes increased the cell size as measured by cell surface area, and also reduced the mRNA expression level of alpha-myosin heavy chain. In accordance, knockdown of endogenous miR-199a in cardiomyocytes reduced the cell size. Down-regulation of miR-199a also attenuated the phenylephrine-induced increase of cell size. Furthermore, bioinformatic algorithms were used to predict the potential targets of miR-199a in cardiac hypertrophy, and hypoxia-inducible factor 1 alpha was confirmed by the luciferase reporter assay to be a potential target of miR-199a. Taken together, our results demonstrated that miR-199a, which was predominantly expressed in cardiomyocytes, was essential for the maintenance of cell size of cardiomyocytes and might play a role in the regulation of cardiac hypertrophy.

Combination therapy with angiotensin-converting enzyme inhibitors and indapamide impairs glucose tolerance in Chinese hypertensive patients

BACKGROUND

Elevated blood glucose (BG) induced by antihypertensive agents increases the risk of cardiovascular events. This study was designed to investigate whether fosinopril+indapamide combination therapy has any effect on glucose tolerance (GT), and if it did, whether conversion to fosinopril alone could reverse the impaired GT.

METHODS

Included in the present study were 124 hypertensive patients, of whom 62 patients were treated with fosinopril plus indapamide (F/I group) and the remaining 62 patients were treated with fosinopril alone (F group). Of them, 89 patients completed a mean of 14-month follow-up. In the F/I group, 29 patients were converted to the use of fosinopril for 4-12 months after they completed the follow-up.

RESULTS

In the F group, fasting BG decreased significantly from 5.1+/-0.5 to 4.8+/-0.7 mmol/l (p<0.01), and 2-h postprandial BG decreased significantly from 7.2+/-1.6 to 6.4+/-1.4 mmol/l (p<0.01), while in the F/I group, fasting BG increased significantly from 5.1 +/-0.6 to 5.3+/-0.9 mmol/l (p<0.05), and 2-h postprandial BG increased significantly from 7.2+/-1.7 to 7.7+/-1.8 mmol/l (p<0.05). In 29 patients of the F/I group who completed the follow-up and were converted to fosinopril, fasting BG decreased significantly from 5.5+/-1.0 to 5.3+/-1.0 mmol/l (p<0.05), and 2-h postprandial BG decreased significantly from 7.5+/-2.0 to 7.0+/-2.7 mmol/l (p<0.05).

CONCLUSION

Fosinopril+indapamide combination therapy impaired GT in Chinese hypertensive patients, and fosinopril alone was able to reverse fosinopril+indapamide-induced GT impairment in part of these patients.

Circulating ghrelin and ghrelin to obestatin ratio are low in patients with untreated mild-to-moderate hypertension

Obestatin, encoded by the same gene as ghrelin, was first described as a physiological opponent of ghrelin. We investigated fasting plasma ghrelin and obestatin levels and ratio of ghrelin to obestatin in humans with untreated mild-to-moderate hypertension and humans with normal blood pressure. We found that the plasma concentration of ghrelin and the ratio of ghrelin to obestatin were significantly lower in hypertension group compared with control group (236.3±12.3 pg/ml vs 381.4±25.6 pg/ml, P<0.01; 0.89±0.06 vs 1.2±0.06, P<0.01). The plasma concentration of obestatin was lower in hypertension group compared with control group, but the difference between the two groups was not significant (276.2±15.1 pg/ml vs 325.4±25.8 pg/ml, P>0.05). In a multiple regression model, systolic blood pressure, triglyceride and obestatin were independent predictors of ghrelin (standardized coefficient=-0.332; P=0.019; standardized coefficient=-0.302; P=0.030; standardized coefficient=0.630; P<0.0005, respectively). In another multiple regression model, only ghrelin was an independent predictor of obestatin (standardized coefficient=0.861; P<0.0005). Both systolic blood pressure and triglyceride were independent predictors of ratio of ghrelin to obestatin (standardized coefficient=-0.385; P=0.033; standardized coefficient=-0.430; P=0.018, respectively). Our data suggests that there are disturbances of ghrelin and obestatin in the circulating plasma of humans and the ghrelin/obestatin system might play a role in blood pressure regulation.

Attenuation of microRNA-1 derepresses the cytoskeleton regulatory protein twinfilin-1 to provoke cardiac hypertrophy

MicroRNAs are involved in several aspects of cardiac hypertrophy, including cardiac growth, conduction, and fibrosis. However, their effects on the regulation of the cardiomyocyte cytoskeleton in this pathological process are not known. Here, with microRNA microarray and small RNA library sequencing, we show that microRNA-1 (miR-1) is the most abundant microRNA in the human heart. By applying bioinformatic target prediction, a cytoskeleton regulatory protein twinfilin-1 was identified as a potential target of miR-1. Overexpression of miR-1 not only reduced the luciferase activity of the reporter containing the 3' untranslated region of twinfilin-1 mRNA, but also suppressed the endogenous protein expression of twinfilin-1, indicating that twinfilin-1 is a direct target of miR-1. miR-1 was substantially downregulated in the rat hypertrophic left ventricle and phenylephrine-induced hypertrophic cardiomyocytes, and accordingly, the protein level of twinfilin-1 was increased. Furthermore, overexpression of miR-1 in hypertrophic cardiomyocytes reduced the cell size and attenuated the expression of hypertrophic markers, whereas silencing of miR-1 in cardiomyocytes resulted in the hypertrophic phenotype. In accordance, twinfilin-1 overexpression promoted cardiomyocyte hypertrophy. Taken together, our results demonstrate that the cytoskeleton regulatory protein twinfilin-1 is a novel target of miR-1, and that reduction of miR-1 by hypertrophic stimuli induces the upregulation of twinfilin-1, which in turn evokes hypertrophy through the regulation of cardiac cytoskeleton.

Percutaneous establishment of tricuspid regurgitation: an experimental model for transcatheter tricuspid valve replacement

BACKGROUND

Valve replacement or repair is recommended in patients with tricuspid regurgitation when deterioration of their clinical status occurs as a consequence of right ventricular dysfunction. Percutaneous valve replacement was developed in recent years. To investigate the feasibility, effectiveness and long-term results of percutaneous tricuspid valve replacement, an experimental model with tricuspid regurgitation is needed. We developed a simple and reproducible percutaneous approach for the creation of tricuspid regurgitation in sheep.

METHODS

A specially designed grasping forceps were used to grasp chordae tendineae or the tricuspid valve leaflets through a catheter. Transcatheter creation of tricuspid regurgitation was performed on 7 healthy sheep. These sheep were followed up shortly after the procedure and at 6th month post-procedure with echocardiography. Additionally, all the sheep were sacrificed for anatomic evaluation at 6th month after the procedure.

RESULTS

Creation of tricuspid regurgitation was successfully accomplished in all sheep. Necropsy confirmed that damage was done to the tricuspid valve apparatus in all animals (tearing of the anterior leaflet of the tricuspid valve in five animals and posterior leaflet of the tricuspid valve in two animals). At the six-month follow-up, there was no significant increase in the right ventricle dimension and ejection fraction measured by echocardiography. Autopsy examinations demonstrated the tearing of tricuspid valve leaflets.

CONCLUSIONS

The creation of an animal model of tricuspid regurgitation via a percutaneous approach using forceps to sever one or more tricuspid leaflets is feasible and will allow investigation of devices designed replace the tricuspid valve via a percutaneous approach. Despite significant tricuspid regurgitation, the hemodynamics did not change during the follow-up period in this model.

Circulating microRNA: a novel potential biomarker for early diagnosis of acute myocardial infarction in humans

AIMS

microRNA (miRNA) is reported to be present in the blood of humans and has been increasingly suggested as a biomarker for diseases. We aim to determine the potential of cardiac-specific miRNAs in circulation to serve as biomarkers for acute myocardial infarction (AMI).

METHODS AND RESULTS

By verifying their tissue expression patterns with real-time polymerase chain reaction (PCR) analysis, muscle-enriched miRNAs (miR-1, miR-133a, and miR-499) and cardiac-specific miR-208a were selected as candidates for this study. With miRNA microarray and real-time PCR analyses, miR-1, miR-133a, and miR-499 were present with very low abundance, and miR-208a was absent in the plasma from healthy people. In the AMI rats, the plasma levels of these miRNAs were significantly increased. Especially, miR-208a in plasma was undetected at 0 h, but was significantly increased to a detectable level as early as 1 h after coronary artery occlusion. Further evaluation of the miRNA levels in plasma from AMI patients (n = 33) demonstrated that all four miRNA levels were substantially higher than those from healthy people (n = 30, P < 0.01), patients with non-AMI coronary heart disease (n = 16, P < 0.01), or patients with other cardiovascular diseases (n = 17, P < 0.01). Notably, miR-208a remained undetectable in non-AMI patients, but was easily detected in 90.9% AMI patients and in 100% AMI patients within 4 h of the onset of symptoms. By receiver operating characteristic curve analysis, among the four miRNAs investigated, miR-208a revealed the higher sensitivity and specificity for diagnosing AMI.

CONCLUSION

Elevated cardiac-specific miR-208a in plasma may be a novel biomarker for early detection of myocardial injury in humans.

Plasma ghrelin and obestatin levels are increased in spontaneously hypertensive rats

Obestatin, encoded by the same gene as ghrelin, was first described as a physiological opponent of ghrelin. We investigated fasting plasma ghrelin and obestatin levels in spontaneously hypertensive rats and Wistar-Kyoto rats. We found that ghrelin levels, obestatin levels and the ratio of ghrelin to obestatin were significantly higher in spontaneously hypertensive rats than Wistar-Kyoto rats. Systolic blood pressure and diastolic blood pressure were positively correlated; however, heart period and baroreflex sensitivity were negatively correlated with ghrelin levels. Systolic blood pressure was positively correlated, whereas baroreflex sensitivity was negatively correlated with obestatin levels. In addition, systolic blood pressure was a significantly independent variable of ghrelin levels, obestatin levels, and the ghrelin to obestatin ratio in a multiple regression analysis. Our data suggests that there is a disturbance of ghrelin and obestatin in the circulation of spontaneously hypertensive rats and the ghrelin/obestatin system might play a role in blood pressure regulation.

Transcatheter closure of perimembranous ventricular septal defects using a novel wire-maintaining technique

OBJECTIVES

We aimed to evaluate the clinical feasibility and safety of a novel wire-maintaining technique (WMT) for transcatheter closure of perimembranous ventricular septal defects (PmVSDs).

BACKGROUND

Transcatheter device closure of PmVSDs has been increasingly performed and this procedure is now offered as primary therapy at many institutions.

METHODS

A total of 103 patients with complex PmVSDs were randomized to either the conventional technique (CT) group (n = 51) or the WMT group (n = 52). In the CT group, the track wire was withdrawn before the occluder insertion and deployment. If inappropriate, the initial occluder was withdrawn and the "arteriovenous wire loop" was re-established. In the WMT group, the track wire was maintained in the delivery sheath during the procedure. If the initial occluder was inappropriate, the delivery sheath could be reintroduced over the maintained wire.

RESULTS

For those patients who could not achieve optimal results with the initially selected occluders and required further device replacement, the procedure and fluoroscope time was reduced significantly in the WMT group compared with the CT group ([50.8 +/- 13.2] min vs. [61.5 +/- 15.4] min, P < 0.01 and [21.6 +/- 8.6] min vs. [27.3 +/- 7.4] min, P < 0.05; respectively). There was no difference in the incidence of complications of two groups.

CONCLUSIONS

The WMT was feasible and safe for the transcatheter treatment of PmVSDs, especially for those complex defects with great challenge. Using this novel technique, the reconstruction of "arteriovenous wire loop" could be avoided in patients requiring device replacement.

Disturbance of circulating ghrelin and obestatin in chronic heart failure patients especially in those with cachexia

Plasma ghrelin was elevated in chronic heart failure (CHF) patients with cachexia. Obestatin, a sibling of ghrelin, opposes several actions of ghrelin. We, therefore, investigated plasma obestatin and ghrelin levels in patients with CHF. Total plasma ghrelin and obestatin levels were measured in 65 patients with CHF (22 with cardiac cachexia) and 15 controls. Ghrelin levels were significantly higher in patients with cachexia (1237.8+/-47.9 pg/ml) than those without cachexia (P=0.041) and controls (P<0.01). Obestatin levels correlated positively with ghrelin levels, and obestatin levels were significantly increased in patients with cachexia (282.3+/-13.0 pg/ml) than patients without cachexia and controls (both P<0.01). However, the ghrelin to obestatin ratios (4.5+/-0.2) were significantly lower in CHF patients with cachexia than controls (P<0.01). Ghrelin and ratio of ghrelin to obestatin were independent predictors of the development of cardiac cachexia. No association was found between ghrelin, obestatin and New York Heart Association functional class, brain natriuretic peptide. There was disturbance of circulating ghrelin and obestatin in the CHF patients especially those with cachexia, which may have a role in the pathogenesis of cardiac cachexia in CHF.