Cheng-Huang Su

Reduction of connexin43 in human endothelial progenitor cells impairs the angiogenic potential

Our previous work showed that arsenic trioxide down-regulated Cx43 and attenuated the angiogenic potential of human late endothelial progenitor cells (EPC). However, the relation between Cx43 and angiogenic activity of the EPC remained unclear. In the study, human late EPC were treated with siRNA specific to Cx43 (Cx43siRNA). The expression profiles as well as activity of the treated cells were examined. In parallel, the angiogenic potential of human EPC treated with Cx43siRNA was evaluated using murine hind limb ischemic model. The results showed that, in the EPC treated with Cx43siRNA, the activity of migration, proliferation, and angiogenic potential were attenuated, accompanied by reduction in vascular endothelial growth factor (VEGF) expression. In hind limb ischemia mice, EPC treated with Cx43siRNA lost the therapeutic angiogenic potential. VEGF supplementation partially recovered the activity impaired by Cx43 down-regulation. In conclusion, reduced Cx43 expression per se in the EPC causes decreased expression of VEGF and impaired angiogenic potential of the cells. Prevention of Cx43 reduction is a potential target to maintain the angiogenic potential of the EPC.

2017 Taiwan lipid guidelines for high risk patients

In Taiwan, the prevalence of hyperlipidemia increased due to lifestyle and dietary habit changes. Low density lipoprotein cholesterol (LDL-C) and non-high density lipoprotein cholesterol (non-HDL-C) are all significant predicting factors of coronary artery disease in Taiwan. We recognized that lipid control is especially important in patients with existed atherosclerotic cardiovascular diseases (ASCVD), including coronary artery disease (CAD), ischemic stroke and peripheral arterial disease (PAD). Because the risk of ASCVD is high in patients with diabetes mellitus (DM), chronic kidney disease (CKD) and familial hypercholesterolemia (FH), lipid control is also necessary in these patients. Lifestyle modification is the first step to control lipid. Weight reduction, regular physical exercise and limitation of alcohol intake all reduce triglyceride (TG) levels. Lipid-lowering drugs include HMG-CoA reductase inhibitors (statins), cholesterol absorption inhibitors (ezetimibe), proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors, nicotinic acids (niacin), fibric acids derivatives (fibrates), and long-chain omega-3 fatty acids. Statin is usually the first line therapy. Combination therapy with statin and other lipid-lowering agents may be considered in some clinical settings. For patients with acute coronary syndrome (ACS) and stable CAD, LDL-C < 70 mg/dL is the major target. A lower target of LDL-C <55 mg/dL can be considered in ACS patients with DM. After treating LDL-C to target, non-HDL-C can be considered as a secondary target for patients with TG ≥ 200 mg/dL. The suggested non-HDL-C target is < 100 mg/dL in ACS and CAD patients. For patients with ischemic stroke or transient ischemic attack presumed to be of atherosclerotic origin, statin therapy is beneficial and LDL-C < 100 mg/dL is the suggested target. For patients with symptomatic carotid stenosis or intracranial arterial stenosis, in addition to antiplatelets and blood pressure control, LDL-C should be lowered to < 100 mg/dL. Statin is necessary for DM patients with CV disease and the LDL-C target is < 70 mg/dL. For diabetic patients who are ≥ 40 years of age, or who are < 40 years of age but have additional CV risk factors, the LDL-C target should be < 100 mg/dL. After achieving LDL-C target, combination of other lipid-lowering agents with statin is reasonable to attain TG < 150 mg/dL and HDL-C >40 in men and >50 mg/dL in women in DM. LDL-C increased CV risk in patients with CKD. In adults with glomerular filtration rate (GFR) < 60 mL/min/1.73m2 without chronic dialysis (CKD stage 3-5), statin therapy should be initiated if LDL-C ≥ 100 mg/dL. Ezetimibe can be added to statin to consolidate the CV protection in CKD patients. Mutations in LDL receptor, apolipoprotein B and PCSK9 genes are the common causes of FH. Diagnosis of FH usually depends on family history, clinical history of premature CAD, physical findings of xanthoma or corneal arcus and high levels of LDL-C. In addition to conventional lipid lowering therapies, adjunctive treatment with mipomersen, lomitapide, or PCSK9 inhibitors become necessary to further reduce LDL-C in patients with FH. Overall, these recommendations are to help the health care professionals in Taiwan to treat hyperlipidemia with current scientific evidences. We hope the prescription rate of lipid lowering drugs and control rate of hyperlipidemia in high risk patients could be increased by implementation of the clinical guidelines. The major purpose is to improve clinical outcomes of these high risk patients through the control of hyperlipidemia.

Diabetes Reduces Aortic Endothelial Gap Junctions in ApoE-deficient Mice: Simvastatin Exacerbates the Reduction

We examined the endothelial gap junctions in diabetic hyperlipidemic mice. Male apolipoprotein E (apoE)-deficient mice were made diabetic by streptozotocin. Three weeks later, the animals were treated with simvastatin for 2 weeks. The expression of aortic gap junctions in the non-diabetic (n=10), untreated diabetic (n=10), and simvastatin-treated diabetic animals (n=6) was analyzed. There was a >4-fold increase in serum cholesterol level and >50% increase in plaque areas in the diabetic mice, regardless of simvastatin treatment. Western blotting of aortae showed reduced expression of connexin37 (Cx37) and Cx40 in the diabetic mice, which were further decreased in the simvastatin-treated diabetic mice. Immunoconfocal microscopy showed that endothelial gap junctions made of Cx37 and Cx40 were both reduced in the untreated diabetic mice compared with the non-diabetic mice (decrease: Cx37, 41%; Cx40, 42%; both p<0.01). The reduction was greater in the simvastatin-treated mice (decrease in treated diabetic vs non-diabetic: Cx37, 61%; Cx40, 79%; both p<0.01; decrease in treated diabetic vs untreated diabetic: Cx37, 34%; Cx40, 63%; both p<0.01). Cx37 and Cx40 were decreased in the endothelium of plaque surface. Cx43 appeared in the medial layer and inner layer of the intima. All three connexins were rarely expressed in monocytes/macrophages inside the plaques. In conclusion, in apoE-deficient mice, streptozotocin-induced diabetes is associated with downregulation of endothelial Cx37 and Cx40 gap junctions. Short-term treatment with simvastatin exacerbates the downregulation.

Nonviral gene therapy targeting cardiovascular system.

The goal of gene therapy is either to introduce a therapeutic gene into or replace a defective gene in an individuals cells and tissues. Gene therapy has been urged as a potential method to induce therapeutic angiogenesis in ischemic myocardium and peripheral tissues after extensive investigation in recent preclinical and clinical studies. A successful gene therapy mainly relies on the development of the gene delivery vector. Developments in viral and nonviral vector technology including cell-based gene transfer will further improve transgene delivery and expression efficiency. Nonviral approaches as alternative gene delivery vehicles to viral vectors have received significant attention. Recently, a simple and safe approach of gene delivery into target cells using naked DNA has been improved by combining several techniques. Among the physical approaches, ultrasonic microbubble gene delivery, with its high safety profile, low costs, and repeatable applicability, can increase the permeability of cell membrane to macromolecules such as plasmid DNA by its bioeffects and can provide as a feasible tool in gene delivery. On the other hand, among the promising areas for gene therapy in acquired diseases, ischemic cardiovascular diseases have been widely studied. As a result, gene therapy using advanced technology may play an important role in this regard. The aims of this review focus on understanding the cellular and in vivo barriers in gene transfer and provide an overview of currently used chemical vectors and physical tools that are applied in nonviral cardiovascular gene transfer.

Association of low serum albumin concentration and adverse cardiovascular events in stable coronary heart disease

OBJECTIVE Coronary heart disease (CHD) is a leading cause of death in developed countries. Exploration of indicators to identify high risk individuals who develop adverse outcomes despite stable baseline condition is important. This study is to evaluate the association between serum albumin concentration and cardiovascular (CV) outcomes in individuals of stable CHD. METHODS Seven-hundred-thirty-four participants from Biosignature study, a nationwide prospective cohort study aimed to identity risk factors among patients with stable CHD, were enrolled for analysis. They were divided into low serum albumin group (baseline albumin concentration <3.5g/dL, n=98) and normal albumin group (baseline albumin concentration ≥3.5g/dL, n=636). The relations between baseline albumin and adverse CV outcomes within 18months of follow-up were analyzed. RESULTS Compared baseline characteristics with normal albumin group, subjects in low albumin group are older, having more diabetic patients, lower hemoglobin level, lower estimated glomerular filtration rate, lower total cholesterol level, lower left ventricular ejection fraction, and higher blood glucose. While there is no significant difference of total CV events between two groups, low serum albumin concentration is associated with an increased risk of all-cause mortality (10.2% vs. 0.5%, p<0.001) and hard CV events (7.1% vs. 1.4%, p<0.001). The association remains significant after adjustments for confounders (all-cause mortality, HR: 6.81, 95% CI: 1.01-45.62; hard CV events, HR: 3.68, 95% CI: 1.03-13.19). CONCLUSIONS Low serum albumin concentration (<3.5g/dL) worsens prognosis of patients with stable CHD.

Ultrasonic Microbubble-Mediated Gene Delivery Causes Phenotypic Changes of Human Aortic Endothelial Cells

Ultrasound, in combination with microbubbles, serves as a feasible nonviral method in vascular gene delivery. However, the effects of ultrasonic microbubble transfection (UMT) on vascular endothelial cells remained unclear. We therefore investigated whether UMT itself causes phenotypic changes of the human aortic endothelial cells (HAEC) in vitro. HAEC were cultured with solution containing luciferase reporter gene and microbubbles followed by exposure to ultrasound of selected parameters. Thereafter, the proliferation and migration activities of HAEC were investigated. Real-time RT-PCR and/or western blotting were performed to assess expression profile of HAEC, including growth-related factors (vascular endothelial growth factor, fins-like tyrosine kinase-1 [Flt-1] and kinase insert domain-containing receptor [KDR]), coagulatory factor (von Willebrand factor), vasodilatory enzyme (endothelial nitric oxide synthase), gap junctional protein connexin43 and adhesion molecules (P-selectin, intercellular adhesion molecule 1 and vascular cell adhesion molecule 1). The results showed that in conditions where UMT lead to expression of luciferase, proliferation capacity is enhanced (p<0.001), partly attributable to the effect of ultrasound (p<0.05), after excluding the effect of contact inhibition. In addition, the expression of KDR and Flt-1 were found increased at either the mRNA level, protein level, or both (p<0.05). Other markers did not have significant changes (all p>0.2). Similarly, the migration capacity was minimally changed (p>0.3). In conclusion, UMT causes phenotypic changes of HAEC by enhancing proliferation and upregulating KDR and Flt-1, while possesses no obvious adverse effect on viable transfected cells. Further investigation is required to clarify the impact of these changes by UMT in vivo.

Nonviral Technologies for Gene Therapy in Cardiovascular Research

SUMMARY Gene therapy, which is still at an experimental stage, is a technique that attempts to correct or prevent a disease by delivering genes into an individual’s cells and tissues. In gene delivery, a vector is a vehicle for transferring genetic material into cells and tissues. Synthetic vectors are considered to be prerequisites for gene delivery, because viral vectors have fundamental problems in relation to safety issues as well as large-scale production. Among the physical approaches, ultrasound with its associated bioeffects such as acoustic cavitation, especially inertial cavitation, can increase the permeability of cell membranes to macromolecules such as plasmid DNA. Microbubbles or ultrasound contrast agents lower the threshold for cavitation by ultrasound energy. Furthermore, ultrasound-enhanced gene delivery using polymers or other nonviral vectors may hold much promise for the future but is currently at the preclinical stage. We all know aging is cruel and inevitable. Currently, among the promising areas for gene therapy in acquired diseases, the incidences of cancer and ischemic cardiovascular diseases are strongly correlated with the aging process. As a result, gene therapy technology may play important roles in these diseases in the future. This brief review focuses on understanding the barriers to gene transfer as well as describing the useful nonviral vectors or tools that are applied to gene delivery and introducing feasible models in terms of ultrasound-based gene delivery. [International Journal of Gerontology 2008; 2(2): 35–47]

Excessive interatrial adiposity is associated with left atrial remodeling, augmented contractile performance in asymptomatic population

Abstract Purpose Pericardial adipose tissue had been shown to exert local effects on adjacent cardiac structures. Data regarding the mechanistic link between such measures and left atrial (LA) structural/functional remodeling, a clinical hallmark of early stage heart failure (HF) and atrial fibrillation (AF) incidence, in asymptomatic population remain largely unexplored. Methods This retrospective analysis includes 356 subjects free from significant valvular disorders, atrial fibrillation, or clinical HF. Regional adipose tissue including pericardial and periaortic fat volumes, interatrial septal (IAS), and left atrioventricular groove (AVG) fat thickness were all measured by multidetector computed tomography (MDCT) (Aquarius 3D Workstation, TeraRecon, San Mateo, CA, USA). We measured LA volumes, booster performance, reservoir capacity as well as conduit function, and analyzed their association with adiposity measures. Results All four adiposity measures were positively associated with greater LA volumes (all P < 0.05), while IAS and AVG fat were also related to larger LA kinetic energy and worse reservoir capacity (both P < 0.01). In multivariate models, IAS fat thickness remained independently associated with larger LA volumes, increased LA kinetic energy and ejection force (β-coef: 0.17 & 0.15, both P < 0.05), and impaired LA reservoir and conduit function (β-coef: −0.20 & −0.12, both P < 0.05) after adjusting for clinical variables. Conclusion Accumulated visceral adiposity, especially interatrial fat depots, was associated with certain LA structural/functional remodeling characterized by impaired LA reservoir and conduit function though augmented kinetic energy and ejection performance. Our data suggested that interatrial fat burden may be associated with certain detrimental LA functions with compensatory LA adaptation in an asymptomatic population.

Ultrasound-based and Non-viral Technologies in Gene Therapy

Gene therapy is a technique for the purpose of correcting or preventing a disease by delivering genes into an individuals cells and tissues. Gene therapy is still in its infancy and at an experimental stage. Synthetic vectors are considered to be a prerequisite for gene deliveries, as viral vectors have fundamental problems in relation to safety issues, as well as large-scale production. Among the physical approaches, ultrasound with its bioeffects-acoustic cavitation, especially inertial cavitation, can increase the permeability of cell membrane to macromolecules such as plasmid DNA. Microbubbles, or ultrasound contrast agents, lower the threshold for cavitation by ultrasound energy. Furthermore, ultrasound-enhanced gene delivery using polymers or other non-viral vectors, though also in its preclinical stage may hold a lot of promise for the future. The aims of this brief review focus on understanding of the barriers to gene transfer and useful vectors or tools that are applied in gene delivery and on introducing the feasible models in terms of ultrasound-based gene delivery.

Current Trends from Diagnosis to Treatment in Heart Failure

近年來全球人口老化，導致心臟衰竭快速成長，變成全世界健康照護上重大的威脅。雖然心臟衰竭已有明確的治療指引，但還是造成相當高比例的心血管併發症及死亡率。最新的歐洲以及美國心臟學會發表新一代心衰竭藥物以及跨團隊治療，可更加改善病人症狀及增加存活率。本文簡要地整理不同類型心臟衰竭的診斷和治療流程，以供臨床醫師治療之參考。