Chunsheng Wang

Circulating matrix metalloproteinase patterns in association with aortic dilatation in bicuspid aortic valve patients with isolated severe aortic stenosis

AbstractBicuspid aortic valve (BAV) exhibits a clinical incline toward aortopathy, in which aberrant tensile and shear stress generated by BAV can induce differential expression of matrix metalloproteinases (MMPs) and their endogenous tissue inhibitors (TIMPs). Whether stenotic BAV, which exhibits additional eccentric high-velocity flow jet upon ascending aorta and further worsens circumferential systolic wall shear stress than BAV with echocardiographically normal aortic valve, can lead to unique plasma MMP/TIMP patterns is still unknown. According to their valvulopathy and aortic dilatation status, 93 BAV patients were included in the present study. Group A (nxa0=xa037) and B (nxa0=xa028) comprised severely stenotic patients with or without ascending aorta dilatation; Group C (nxa0=xa012) and D (nxa0=xa016) comprised echocardiographically normal BAV patients withnor without ascending aorta dilatation. Plasma MMP/TIMP levels (MMP-1, -2, -3, -8, -9, -10, -13 and TIMP-1, -2, -4) were determined via a multiplex ELISA detection system in a single procedure. Among patients with isolated severe aortic stenosis, plasma levels of MMP-2 and -9 were significantly elevated when ascending aortic dilatation was present (pxa0=xa00.001 and pxa0=xa00.002, respectively). MMP-2, however, remained as the single elevated plasma component among echocardiographically normal BAV patients with dilated ascending aorta (pxa0=xa00.027). Multivariate analysis revealed that MMP-2 and MMP-9 could both serve as independent risk factor for aortic dilatation in the case of isolated severe stenosis (pxa0=xa00.003 and pxa0=xa00.001, respectively), and MMP-2 in echocardiographically normal patients (pxa0=xa00.002). In conclusion, BAV patients with isolated severe aortic stenosis demonstrated a distinct plasma MMP/TIMP pattern, which might be utilized as circulating biomarkers for early detection of aortic dilatation.

Nanoparticle-enhanced generation of gene-transfected mesenchymal stem cells for in vivo cardiac repair.

Transplantation of gene-transfected bone marrow-derived mesenchymal stem cells (BMMSCs) is a promising strategy for ischemic myocardium repair, but current therapeutic strategy suffers from high toxicity and inefficient gene transfection in primary BMMSCs. Here we designed and synthesized molecularly organic-inorganic hybrid hollow mesoporous organosilica nanoparticles (HMONs) based on nano-synthetic chemistry, which are featured with concurrent large pore size over 20xa0nm, small particulate size, hollow cavity and high dispersity for gene transfection in BMMSCs and subsequent inxa0vivo cardiac repair. To efficiently create the therapeutic gene-transfected stem-cell lines, hepatocyte growth factor (HGF) gene was applied to transfect BMMSCs via biocompatible surface-engineered HMONs as a high-performance gene-delivery nanosystem. On the rat model of myocardial infarction, transplantation of HGF gene-transfected BMMSCs enables the largely decreased apoptotic cardiomyocytes, reduced infarct scar size, relieved interstitial fibrosis, and increased angiogenesis in myocardium. The resultant cardiac repair further promotes the significant improvement of heart function. Therefore, the fabricated organic-inorganic hybrid HMONs with large pore size represent a generalizable strategy and platform for gene transfection in BMMSCs and further regenerative medicine.

Novel vascular endothelial growth factor gene delivery system-manipulated mesenchymal stem cells repair infarcted myocardium

Transplantation of vascular endothelial growth factor (VEGF) gene-manipulated mesenchymal stem cells (MSCs) has been proposed as a promising therapy strategy for cardiac repair after myocardium infarction. However, the gene delivery system, including targeted VEGF gene and delivery vehicle, still needs to be optimized. In this study, a novel, hyperbranched poly(amidoamine) (hPAMAM), polymer-based, hypoxia-regulated VEGF165 plasmid (pHRE-VEGF165) delivery system was constructed for effective, biocompatible and controllable gene expression. The hPAMAM demonstrated high transfection efficiency (38.98 ± 1.95%) with minor cytotoxicity (cell viability = 92.38 ± 1.09%) in primary MSCs under optimal conditions. Under hypoxia, hPAMAM-pHRE-hVEGF165-transfected MSCs could over-express hVEGF165 stably for 14 days, with a peak expression at day 2, which promoted endothelial cell proliferation in vitro. The transplantation of hPAMAM-pHRE-hVEGF165 gene delivery system-manipulated MSCs could enhance ischemic myocardium VEGF concentration obviously, which improved the graft MSC survival, increased neovascularization, and ultimately preserved cardiac function to a significantly greater degree than untreated MSC transplantation. This work demonstrated that hPAMAM-based pHRE-hVEGF165 gene delivery combined with MSC transplantation is an economical, feasible and biocompatible strategy for cardiac repair.

Novel hyperbranched polyamidoamine nanoparticle based gene delivery: Transfection, cytotoxicity and in vitro evaluation

In this study, hyperbranched polyamidoamine (hPAMAM) was developed as a novel non-viral gene vector for the first time. The hPAMAM was synthesized using a modified one-pot method. DNA was then bound to hPAMAM at different weight ratios (w(hPAMAM)/w(DNA)). The higher weight ratio could bring larger particle size and higher zeta potential of hPAMAM-DNA complexes. The encapsulated DNA was protected by hPAMAM from degradation for over 3h. Under the optimal condition, high gene transfection efficiency could be achieved in COS7 (47.47 ± 1.42%) and HEK293 (40.8 ± 0.98%) cell lines. And hPAMAM showed rather minor cytotoxicity in vitro (cell viability=91.38 ± 0.46% in COS7 and 92.38 ± 0.61% in HEK293). The hPAMAM mediated human vascular endothelial growth factor 165 (hVEGF(165)) gene transfected cells could express hVEGF(165) stably for 14 days, with the peak expression at day 2. In conclusion, hPAMAM based gene delivery was economical, effective and biocompatible, and may serve as a promising non-viral vehicle for gene therapy.

Enhanced infarct myocardium repair mediated by thermosensitive copolymer hydrogel-based stem cell transplantation

Mesenchymal stem cell (MSC) transplantation by intramyocardial injection has been proposed as a promising therapy strategy for cardiac repair after myocardium infarction. However, low retention and survival of grafted MSCs hinder its further application. In this study, copolymer with N-isopropylacrylamide/acrylic acid/2-hydroxylethyl methacrylate-poly(ɛ-caprolactone) ratio of 88:9.6:2.4 was bioconjugated with type I collagen to construct a novel injectable thermosensitive hydrogel. The injectable and biocompatible hydrogel-mediated MSC transplantation could enhance the grafted cell survival in the myocardium, which contributed to the increased neovascularization, decreased interstitial fibrosis, and ultimately improved heart function to a significantly greater degree than regular MSC transplantation. We suggest that this novel hydrogel has the potential for future stem cell transplantation.

Reprogramming fibroblasts to pluripotency using arginine-terminated polyamidoamine nanoparticles based non-viral gene delivery system.

Induced pluripotent stem cells (iPSCs) have attracted keen interest in regenerative medicine. The generation of iPSCs from somatic cells can be achieved by the delivery of defined transcription factor (Oct4, Sox2, Klf4, and c-Myc[OSKM]). However, most instances of iPSC-generation have been achieved by potentially harmful genome-integrating viral vectors. Here we report the generation of iPSCs from mouse embryonic fibroblasts (MEFs) using arginine-terminated generation 4 polyamidoamine (G4Arg) nanoparticles as a nonviral transfection vector for the delivery of a single plasmid construct carrying OSKM (pOSKM). Our results showed that G4Arg nanoparticles delivered pOSKM into MEFs at a significantly higher transfection efficiency than did conventional transfection reagents. After serial transfections of pOSKM-encapsulated G4Arg nanoparticles, we successfully generated iPSCs from MEFs. Our study demonstrates that G4Arg nanoparticles may be a promising candidate for generating of virus-free iPSCs that have great potential for clinical application.

Transplantation of novel vascular endothelial growth factor gene delivery system manipulated skeletal myoblasts promote myocardial repair

BACKGROUNDnSkeletal myoblast (SkM) transplantation combined with vascular endothelial growth factor (VEGF) gene delivery has been proposed as a promising therapy for cardiac repair. Nevertheless, the defective gene vectors and unregulable VEGF expression in vivo hinder its application. Therefore, the search for an economical, effective, controllable gene delivery system is quite necessary.nnnMETHODSnIn our study, hyperbranched polyamidoamine (h-PAMAM) dendrimer was synthesized as a novel gene delivery vector using a modified method. And hypoxia-regulated human VEGF-165 plasmids (pHRE-hVEGF165) were constructed for controllable VEGF gene expression. The efficiency and feasibility of h-PAMAM-HRE-hVEGF165 gene delivery system manipulated SkM transplantation for cardiac repair were investigated in myocardial infarction models.nnnRESULTSnThe h-PAMAM encapsulated pHRE-hVEGF165 could resist nuclease digestion for over 120 min. In primary SkMs, h-PAMAM-pHRE-hVEGF165 gene delivery system showed high transfection efficiency (43.47 ± 2.22%) and minor cytotoxicity (cell viability = 91.38 ± 0.48%). And the transfected SkMs could express hVEGF165 for 18 days under hypoxia in vitro. For myocardial infarction models, intramyocardial transplantation of the transfected SkMs could result in reduction of apoptotic myocardiocytes, improvement of grafted cell survival, decrease of infarct size and interstitial fibrosis, and increase of blood vessel density, which inhibited left ventricle remodeling and improved heart function at the late phase following infarction.nnnCONCLUSIONSnThese results indicate that h-PAMAM based pHRE-hVEGF165 gene delivery into SkMs is feasible and effective, and may serve as a novel and promising gene therapy strategy in ischemic heart disease.

Type A aortic dissection in patients with bicuspid or tricuspid aortic valves: a retrospective comparative study in 288 Chinese patients

OBJECTIVESnThe propensity for aortic aneurysm and dissection bestows bicuspid aortic valves (BAVs), the most common congenital cardiac abnormality, a potentially lethal aspect and considerable clinical concern. In the present study, we attempted to better characterize BAV patients with acute type A aortic dissection (AAD).nnnMETHODSnData from 288 consecutive patients undergoing surgery for acute AAD between December 2007 and April 2012 at our institute were retrospectively collected. Patients were categorized into BAV (n = 30) and tricuspid aortic valve (n = 258) groups to investigate their clinical and prognostic features.nnnRESULTSnBAV patients tended to have younger age, lower systolic blood pressure, higher rate of moderate-to-severe aortic stenosis and wider ascending aorta (all P < 0.05). The 30-day postoperative mortality was significantly higher among BAV patients (23.3 vs 8.1%, P = 0.016), with an elevated proportion of both cardiogenic deaths and complications. BAV patients who died during the follow-up period demonstrated higher incidence of aortic stenosis (57.1 vs 13.0%, P = 0.033), coronary artery ostium involvement (57.1 vs 4.3%, P = 0.006) and longer cardiopulmonary bypass time (190.7 ± 67.5 vs 140.3 ± 37.1 min, P = 0.035).nnnCONCLUSIONSnBAV-associated dissection, as a unique subgroup of AAD, demonstrated strikingly high postoperative mortality in a Chinese population. Moderate-to-severe aortic stenosis and dissection involving coronary artery ostium might be associated with the adverse clinical outcomes among BAV patients.

Novel hyperbranched polyamidoamine nanoparticles for transfecting skeletal myoblasts with vascular endothelial growth factor gene for cardiac repair.

We investigated the feasibility and efficacy of hyperbranched polyamidoamine (hPAMAM) mediated human vascular endothelial growth factor-165 (hVEGF165) gene transfer into skeletal myoblasts for cardiac repair. The hPAMAM was synthesized using a modified one-pot method. Encapsulated DNA was protected by hPAMAM from degradation for over 120xa0min. The transfection efficiency of hPAMAM in myoblasts was 82.6xa0±xa07.0% with cell viability of 94.6xa0±xa01.4% under optimal conditions. The hPAMAM showed much higher transfection efficiency (Pxa0<xa00.05) than polyetherimide and Lipofectamine 2000 with low cytotoxicity. The transfected skeletal myoblasts gave stable hVEGF165 expression for 18xa0days. After transplantation of hPAMAM–hVEGF165 transfected cells, apoptotic myocardial cells decreased at day 1 and heart function improved at day 28, with increased neovascularization (Pxa0<xa00.05). These results indicate that hPAMAM-based gene delivery into myoblasts is feasible and effective and may serve as a novel and promising non-viral DNA vehicle for gene therapy in myocardial infarction.

Coronary Artery Bypass Grafting for Myocardial Bridges of the Left Anterior Descending Artery

Abstractu2002 Background and aim of the study : There is still controversy with regard to adequate therapy for symptomatic patients who are refractory to medical management with myocardial bridges of the left anterior descending artery. This study sought to evaluate the treatment of symptomatic coronary myocardial bridges with coronary artery bypass graft surgery. Methods: Thirteen patients who underwent surgery between October 2005 and May 2008 were included in this study. The mean patient age was 51.3 ± 10.2 years (range, 39–75 years). There were ten men and three women. All 13 patients had angina pectoris preoperatively, and they had myocardial bridges only. Coronary angiography prior to surgery demonstrated myocardial bridging of the left anterior descending artery with systolic compression ≥75% in all patients. They underwent off‐pump coronary artery bypass grafting using the internal mammary artery. Results: The acute clinical success rate was 100% with respect to the absence of myocardial infarction, death, or other major in‐hospital complications. Postoperative coronary CT angiography studies in seven patients after one year demonstrated no graft stenosis. During follow‐up, no patient had symptoms of angina. Conclusions: Coronary artery bypass graft surgery using a LIMA graft is a safe and effective treatment for symptomatic coronary myocardial bridges. (J Card Surg 2012;27:405‐407)