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Pi-Yin Hsiao,1 Hui-Chun Tien,2 Chu-Pin Lo,2 Jyh-Ming Jimmy Juang,3 Yi-Hsin Wang,2 Ruey J Sung41Institute of Life Sciences, National Central University, Taoyuan, Taiwan; 2Department of Financial and Computational Mathematics, Providence University, Taichung, Taiwan; 3Cardiovascular Center and Department of Cardiology, National Taiwan University, Taipei, Taiwan; 4Division of Cardiovascular Medicine, Stanford University School of Medicine, Stanford, CA, USAAbstract: Over the past 15 years, molecular genetic studies have linked gene mutations to many inherited arrhythmogenic disorders, in particular, "ion channelopathies", in which mutations in genes encode functional units of ion channels and/or their transporter-associated proteins in patients without primary cardiac structural abnormalities. These disorders are exemplified by congenital long QT syndrome (LQTS), short QT syndrome, Brugada syndrome (BrS) and catecholaminergic polymorphic ventricular tachycardia (CPVT). Functional and pathophysiological studies have led to better understanding of the clinical spectrum, ion channel structures and cellular electrophysiology involving dynamics of intracellular calcium cycling in many subtypes of these disorders and more importantly, development of potentially more effective pharmacological agents and even curative gene therapy. In this review, we have summarized (1) the significance of unveiling mutations in genes encoding transporter-associated proteins as the cause of congenital LQTS, (2) the technique of catheter ablation applied at the right ventricular outflow tract may be curative for severely symptomatic BrS, (3) mutations with channel function modulated by protein Kinase A-dependent phosphorylation can be the culprit of CPVT mimicry in Andersen-Tawil syndrome (LQT7), (4) ablation of the ion channel anchoring protein may prevent arrhythmogenesis in Timothy syndrome (LQT8), (5) altered intracellular Ca2+ cycling can be the basis of effective targeted pharmacotherapy in CPVT, and (6) the technology of induced pluripotent stem cells is a promising diagnostic and research tool as it has become a new paradigm for pathophysiological study of patient- and disease-specific cells aimed at screening new drugs and eventual clinical application of gene therapy. Lastly, we have discussed (7) genotype-phenotype correlation in relation to risk stratification of patients with congenital LQTS in clinical practice. Keywords: Brugada syndrome, catecholaminergic polymorphic ventricular tachycardia, induced pluripotent stem cells, long QT syndrome, short QT syndrome.

Wei-Chiao Chiu,1 Jyh-ming Juang,1,2 Shen-nan Chang,2 Cho-kai Wu,2 Chia-ti Tsai,2 Chuen-den Tseng,2 Yung-zu Tseng,1,2 Ming-Jai Su,3 Fu-tien Chiang1,2,41Graduate Institute of Physiology, National Taiwan University College of Medicine, 2Division of Cardiology, Department of Internal Medicine, National Taiwan University Hospital and National Taiwan University College of Medicine, 3Graduate Institute of Pharmacology, National Taiwan University College of Medicine, 4Department of Laboratory Medicine, National Taiwan University College of Medicine, Taipei, Taiwan, Republic of ChinaPurpose: Studies to explore angiotensin II (Ang II) and its downstream signaling pathways via Rho guanine nucleotide exchange factors (RhoGEFs) and RhoA signaling are crucial to understanding the mechanisms of smooth muscle contraction leading to hypertension. This study aimed to investigate the Ang II–induced expression of RhoGEFs in vascular smooth muscle cells (VSMCs) of spontaneously hypertensive rats (SHRs) and to identify the possible regulator associated with hypertension.Methods: Cultured VSMCs of the aorta from SHRs and Wistar-Kyoto (WKY) rats were treated with or without Ang II or Ang II plus Ang II type 2 receptor antagonists. The expression levels of RhoGEF messenger RNA (mRNA) and protein were determined. To evaluate the changes of aortic ring contractile force in response to Ang II, a nonviral carrier system was adopted to deliver the leukemia-associated RhoGEF (LARG) small interfering RNA via nanoparticles into aortic rings.Results: The baseline mRNA levels of three RhoGEFs in cultured VSMCs of WKY rats did not increase with age, but they were significantly higher in 12-week-old SHRs than in 5-week-old SHRs. Expression levels of LARG mRNA were higher in SHRs than in age-matched WKY rats. The baseline LAGR protein of 12-week-old SHRs was about four times higher than that of WKY rats of the same age. After Ang II stimulation, LAGR protein expression was significantly increased in 12-week-old WKY rats but remained unchanged in 12-week-old SHRs. LARG small interfering RNA was successfully delivered into aortic rings using nanoparticles. LARG knockdown resulted in 12-week-old SHRs showing the greatest reduction in aortic ring contraction.Conclusion: There were differences in age-related RhoGEF expression at baseline and in response to Ang II stimulation between SHRs and WKY rats in this study. Nanotechnology can assist in studying the silencing of LARG in tissue culture. The findings of this study indicate that LARG gene expression may be associated with the genesis of hypertension in SHRs.Keywords: Rho guanine nucleotide exchange factor, leukemia-associated Rho guanine nucleotide exchange factor, Wistar-Kyoto rats, nanoparticle delivery, hypertension

Hsuan-Li Huang,1 Jyh-Ming Jimmy Juang,2 Hsin-Hua Chou,1,3 Chien-An Hsieh,1 Shih-Jung Jang,1 Shih-Tsung Cheng,1,3 Yu-Lin Ko1,3 1Division of Cardiology, Department of Internal Medicine, Taipei Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, New Taipei City, 2Cardiovascular Center and Division of Cardiology, Department of Internal Medicine, National Taiwan University Hospital, National Taiwan University College of Medicine, Taipei, 3School of Medicine, Tzu Chi University, Hualien, Taiwan Purpose: To investigate the clinical outcomes of endovascular therapy (EVT) in octogenarians and nonoctogenarians with peripheral arterial disease. Methods: A retrospective analysis of 511 patients (654 affected legs) who underwent EVT between July 2005 and December 2013 was conducted in a prospectively maintained database. Immediate results and long-term vascular outcomes were analyzed and compared between octogenarians and nonoctogenarians. Results: Octogenarians were more likely to be female and have atrial fibrillation (AF), whereas nonoctogenarians had higher rates of obesity, claudication, and medical comorbidities. There were no differences in the rates of EVT success, 30-day major adverse vascular events, and 6-month functional improvement between groups. Over the 10-year follow-up period, the rates of 3-year limb salvage, sustained clinical success, freedom from major cerebrovascular and cardiovascular events, and composite vascular events were similar between groups, but the survival rate was better in nonoctogenarians than in octogenarians (73% vs 63%, respectively, P=0.004). In Cox regression analysis, dependence on dialysis and AF were significant predictors of death (odds ratio [OR] 4.44 in dialyzed and 2.83 in AF patients), major cerebrovascular and cardiovascular events (OR 3.49 and 2.45), and composite vascular events (OR 3.14 and 2.25). Conclusion: EVT in octogenarians was feasible, without an increased risk of periprocedural complications. The rates of limb salvage, sustained clinical success, and long-term vascular events were comparable between groups. Dialysis dependence and AF are independent predictors for poor prognosis in patients with peripheral arterial disease. However, these observations require further confirmation in larger scale studies. Keywords: peripheral artery disease, octogenarians, endovascular therapy, cardiovascular outcomes, dialysis, atrial fibrillation