Bi-li Zhang

Inhibiting microRNA-144 abates oxidative stress and reduces apoptosis in hearts of streptozotocin-induced diabetic mice.

INTRODUCTION Hyperglycemia-induced reactive oxygen species (ROS) generation contributes to the development of diabetic cardiomyopathy. However, little is known about the role of microRNAs in the regulation of ROS formation and myocardial apoptosis in streptozotocin (STZ)-induced diabetic mice. METHODS AND RESULTS It was observed that microRNA-144 (miR-144) level was lower in heart tissues of STZ-induced diabetic mice. High glucose exposure also reduced miR-144 levels in cultured cardiomyocytes. Moreover, miR-144 modulated high glucose-induced oxidative stress in cultured cardiomyocytes by directly targeting nuclear factor-erythroid 2-related factor 2 (Nrf2), which was a central regulator of cellular response to oxidative stress. The miR-144 mimics aggravated high glucose-induced ROS formation and apoptosis in cardiomyocytes, which could be attenuated by treatment with Dh404, an activator of Nrf2. Meanwhile, inhibition of miR-144 suppressed ROS formation and apoptosis induced by high glucose in cultured cardiomyocytes. What was more important is that reduced myocardial oxidative stress and apoptosis and improved cardiac function were identified in STZ-induced diabetic mice when treated with miR-144 antagomir. CONCLUSION Although miR-144 cannot explain the increased oxidative stress in STZ, therapeutic interventions directed at decreasing miR-144 may help to decrease oxidative stress in these hearts. Inhibition of miR-144 might have clinical potential to abate oxidative stress as well as to reduce cardiomyocyte apoptosis and improve cardiac function in diabetic cardiomyopathy.

Bolus intravenous injection of obestatin does not change blood pressure level of spontaneously hypertensive rat

Ghrelin, an endogenous ligand for the GH secretagogue receptor, has been shown to decrease arterial pressure. Obestatin, a sibling of ghrelin derived from preproghrelin, opposes several physiological actions of ghrelin. The aim of this study was to determine the effects of bolus intravenous injection of obestatin on blood pressure in spontaneously hypertensive rats. Three different dosages of obestatin (10, 50, and 100 microg/kg) and one dosage of ghrelin (10 microg/kg) were applied. The mean arterial pressure and heart period were continuously recorded for 30 min after injection of drugs. Baroreflex sensitivity was also investigated. In this study, we first demonstrated that intravenous injection of obestatin showed no significant effects on mean blood pressure (10 microg/kg: 113.8+/-2.0 mmHg vs. 114.4+/-1.6 mmHg; 50 microg/kg: 110+/-2.4 mmHg vs. 109+/-3.2 mmHg; 100 microg/kg: 115.9+/-1.5 mmHg vs. 115.8+/-2.4 mmHg; all P>0.05), heart period (10 microg/kg: 184.7+/-3.9 ms vs. 185.5+/-4.1ms; 50 microg/kg: 185.9+/-4.1 ms vs. 193.4+/-4.5 ms; 100 microg/kg: 137.7+/-4.5 ms vs. 143.9+/-5.6 ms; all P>0.05), or baroreflex sensitivity (10 microg/kg: 0.414+/-0.03 ms/mmHg vs. 0.442+/-0.02 ms/mmHg; 50 microg/kg: 0.453+/-0.04 ms/mmHg vs. 0.439+/-0.01 ms/mmHg; 100 microg/kg: 0.398+/-0.02 ms/mmHg vs. 0.401+/-0.01 ms/mmHg; all P>0.05), however, intravenous injection of ghrelin could decrease mean arterial pressure (115.9+/-1.5 mmHg vs. 108.6+/-3.6 mmHg, P<0.01) and increase heart period (132.4+/-2.8 ms vs. 152.6+/-7.4 ms, P<0.05), but did not change baroreflex sensitivity (0.36+/-0.009 ms/mmHg, P>0.05) in spontaneously hypertensive rats.

Identification and functional analysis of a novel PRKAG2 mutation responsible for Chinese PRKAG2 cardiac syndrome reveal an important role of non-CBS domains in regulating the AMPK pathway

BACKGROUND PRKAG2 gene encodes the γ2 regulatory subunit of AMP-activated protein kinase (AMPK) that acts as a sensor of cellular energy status, and its germline mutations are responsible for PRKAG2 cardiac syndrome (PCS). The majority of missense mutations of cystathionine beta-synthase (CBS) domains found in PCS impair the binding activity of PRKAG2 to adenosine derivatives, and therefore lead to PRKAG2 function impairment and AMPK activity alteration, resulting in a familial syndrome of ventricular preexcitation, conduction defects, and cardiac hypertrophy. However, it is unclear about the PRKAG2 mutation in the non-CBS domain. Here, a Chinese family exhibiting the cardiac syndrome associated with a novel heterozygous PRKAG2 mutation (Gly100Ser) mapped to exon 3 encoding a non-CBS domain is described and the function of this novel mutation was investigated in vitro. METHODS The PRKAG2 G100S and R302Q mutations were constructed by a two-step polymerase chain reaction and then transfected into CCL13 cells by lentivirus vectors. Wild-type PRKAG2 gene transfection was used as a negative control. PRKAG2 expression was determined by Western blot. Immunofluorescence was used to localize the intracellular PRKAG2 proteins. MTT assay was performed to explore the effect of mutations on cell proliferation. Periodic acid-Schiff staining was used for detecting glycogen accumulation. AMPK concentration was measured with enzyme-linked immunosorbent assay. RESULTS Our results showed neither intracellular localization of PRKAG2 nor cell growth was altered. In contrast, PRKAG2 protein expression levels were significantly reduced by this mutation. Furthermore, PRKAG2-mediated activity of AMPK was attenuated, resulting in glycogen metabolism dysregulation. These findings revealed that non-CBS domains of PRKAG2 were essential to the regulation of AMPK activity, similar to CBS. CONCLUSIONS Our study ascribes a crucial regulatory role to the novel PRKAG2 G100S mutation, and reiterates that PCS occurs as a consequence of AMPK signaling abnormality caused by PRKAG2 gene mutations.

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.

Intracoronary infusion of bone marrow-derived mononuclear cells contributes to longstanding improvements of left ventricular performance and remodelling after acute myocardial infarction: A meta-analysis

BACKGROUND Conflicting results exist now on the sustained effects of intracoronary bone marrow-derived mononuclear cells (BMMNCs) infusion in patients with acute myocardial infarction (AMI). METHODS Systematical literature search of PubMed, ISI Web of Science, and Cochrane databases was conducted. We included the randomised controlled trials with at least 12-month follow-up data for AMI patients receiving primary percutaneous coronary intervention in addition to intracoronary BMMNCs transfer or not (the control). Summary statistics were calculated using random-effects models. RESULTS A total of 10 trials with 757 patients were available for analysis. The pooled statistics showed intracoronary administration of BMMNCs significantly improved post-infarction left ventricular ejection fraction (weight mean differences [WMD]=4.04%, 95% confidence intervals [CI], 3.01-5.07%; p<0.01), and attenuated the enlargement of left ventricular end-diastolic volume (WMD=-6.13 ml, 95%CI, -10.56 ml to -1.69 ml; p=0.007) as well as infarct size (WMD=-2.47%, 95%CI, -3.79% to -1.15%; p=0.0002). However, for the major adverse clinical events (MACEs), there appeared to be neutral results (between-group differences of p>0.10). CONCLUSIONS Intracoronary BMMNCs infusion leads to longstanding and moderate improvements of post-infarction left ventricular performance as well as remodelling. Meanwhile, the procedure did not increase the risk of MACEs.

Transcatheter Closure of Intracristal Ventricular Septal Defect With Mild Aortic Cusp Prolapse Using Zero Eccentricity Ventricular Septal Defect Occluder.

BACKGROUND Transcatheter closure is a well-established therapy for patients with perimembranous ventricular septal defects (VSDs), but with limited experience in intracristal VSDs (IVSDs) with aortic cusp prolapse (ACP). METHODSANDRESULTS From 2012 to 2014, we reviewed 38 patients with IVSDs complicated with mild ACP who underwent device closure, and, in light of the findings, assessed the effect of transcatheter intervention on preoperative mild ACP. The zero eccentric VSD occluder was chosen for closure (Shanghai Shape Memory Alloy Ltd, Shanghai, China). The mean defect was 4.8±1.6 mm (range, 2-8) as measured by transthoracic echocardiography and the mean device size was 10.1±2.1 mm (range, 4-14). Placement of the device was successful in 35 patients (92.1%). In the remaining 3 patients (7.9%), major complications occurred and they were converted to surgical intervention: severe aortic regurgitation (AR) in 2 patients and occluder dislodgement in 1 patient. During the follow-up (median 14.2 months; range, 3-24), no deaths, residual shunt, late-onset AR, heart block, or device failure occurred. CONCLUSIONS The mid-term prognostic results of high success rate and low complications rate in this study are inspiring. Transcatheter closure of IVSD with mild ACP can be performed safely and effectively as an alternative to surgery in selected patients.

Percutaneous closure of a giant pseudoaneurysm of the ascending aorta after valve replacement

A 45-year-old male who underwent aortic valve replacement 3 years ago was transferred to our institution on January 13, 2012. He presented with progressive dyspnea, palpitation, orthopnea, abdominal distension and lower limb edema, which developed 1 month after aortic valve replacement. Despite the use of excellent medical therapy, the patient had a deteriorating cardiac function. Cardiac auscultation revealed a grade 3/6 systolic murmur at the right upper sternal border. Chest radiograph showed bilateral pleural effusion, diffuse interstitial markings, and a hugely enlarged heart shadow with a spherical configuration on its right side. Computed tomography angiography (CTA) showed that an aortic pseudoaneurysm originated from an orifice (about 6 mm in diameter) in the ascending aorta. Transthoracic echocardiography (TTE) revealed the giant aortic pseudoaneurysm fistulating into the right atrium (Fig. 1). The fistula measured 10 mm at the diameter and the pseudoaneurysmmeasured 80 × 65 mm at the maximal echocardiographic diameters. Cardiac enlargement showed that the left atrial volume was 72 ml, the left ventricular volume was 118 ml and the right atrial volume was 96 ml with severe tricuspid regurgitation (12 ml). The ejection fraction was 40%. He was considered to be a high-risk candidate for repeat surgery and referred for percutaneous closure on January 15, 2012. An aortic angiogram was performed to confirm the presence of the giant pseudoaneurysm (online Video 1). A modified muscular occluder (Shanghai Shape Memory Alloy Ltd., China) similar to the Amplatzer occluder, was used in this procedure. It was made of a 0.005-in nitinol wire mesh with fabric inside and approved by the State Food and Drug Administration (SFDA) of China in 2003 (Fig. 2). The occluder was delivered via the right femoral artery using a 10French delivery sheath. Final aortogram revealed that there was no residual flow into the pseudoaneurysm and the occluder was wellpositioned (online Videos 2 and 3). The procedure was well tolerated by the patient and completely without immediate complications. Post-operative day 3, TTE demonstrated no residual flow across the pseudoaneurysm. CTA revealed that the occluder was well fixed into the neck of pseudoaneurysm (Fig. 3). At one-year follow-up, chest radiograph showed that the size of the pseudoaneurysm gradually decreased (Fig. 4). TTE showed no residual flow to the pseudoaneurysm, with an ejection fraction of 62%. The left atrial volume was 66 ml, the right atrial volume was 91 ml, and the right atrial volume had decreased from 118 ml to 97 ml. The volume of tricuspid regurgitation had decreased from 12 ml to 2 ml. Furthermore, the patient had no serious health problems and enjoyed a good quality of life during the follow-up.

Self-made side hole balloon for treating no-reflow following percutaneous coronary intervention

Objective To assess the safety and effectiveness of self-made side hole balloon for treating no-reflow following percutaneous coronary intervention(PCI).Methods Twenty-three patients diagnosed with no-reflow during PCI from Jan.2012to Jan.2013 were enrolled.Residual stenosis,thrombosis,dissection,and spasm of coronary artery were excluded.The mean age of the 23patients was(62.0±13.8)years old.Of the 23patients 14had ST segment elevation myocardial infarction(STEMI),and 9underwent elective PCI.There were 11cases with no-reflow in the left anterior descending branch,8in the right coronary artery and 4in the circumflex branch.The drugs(nitroglycerin and tirofiban)were selectively injected into the vessel using self-made side hole balloons.The thrombolysis in myocardial infarction(TIMI)grade before and after procedure,ST segment resolution(STR),ST-T changes for 24and 72hours and complications(perforation, dissection,and thrombosis of coronary artery)were observed postoperatively.Patients were followed up by ECG and echocardiogram at 1month after PCI.Incidence of major adverse cardiovascular events(MACEs)and cardiac function wereobserved 6months after PCI.Results After intracoronary administration of drug therapy,TIMI grade-1flow was found in 3 patients,TIMI grade-2flow in 5patients and TIMI grade-3flow in 15patients.In patients with STEMI,complete resolution(≥70%)was found in 8patients,partial resolution(30%-69%)in 4,and no resolution(30%)in 2.One of the 2patients with ventricular electrical storm was treated with temporary cardiac pacing and drug therapy and recovered within 1week;the other one with pericardial tamponade who was treated with emergency surgery repair died.In 9patients undergoing selected PCI,transient ST segment changes were noted in 3patients which recovered within 1week after conservative treatment;with no perforation,dissection,or thrombosis of coronary artery.One month after discharge,echocardiogram of the 22patients showed a mean left ventricular ejection fraction(LVEF)of(50.6±14.3)%and a fractional shortening in the short axis view of 0.36±0.04,and ECG showed non-specific changes of ST-T in 6patients.In 4patients with STEMI,culprit artery showed TIMI grade-3by angiography performed during PCI for non-culprit vessel 1 month after primary PCI.At 6 months after primary PCI,there was no MACE;18patients were in New York Heart Association ClassⅠand 4in ClassⅡ.ConclusionSelf-made side hole balloon is a safe,economical,effective and convenient method for intracoronary administration of nitroglycerin and tirofiban in treating no-flow during PCI,but the result still needs further verification.