Spatiotemporal Dynamics of Immune Cells in Early Left Venticular Remodeling after Acute Myocardial Infarction in Mice Myocardial infarction (MI) remains a leading cause of morbidity and death. Insufficient delivery of oxygen to the myocardium sets into play a complicated process of repair that involves the temporal recruitment of different immune cells so as to remove debris and necrotic cells expeditiously and form effective scar tissue. Clearly defined and overlapping phases have been identified in the process, which transitions from an overall pro-inflammatory to anti-inflammatory phenotype with time. Variations in the strength of the phases as well as in the co-ordination among them has profound consequences. Too strong of an inflammatory phase can result in left ventricular wall thinning and eventual rupture, whereas too strong an anti-inflammatory phase can lead to cardiac stiffening, arrhythmias, or ventricular aneurisms. In both cases, heart failure is an intermediate consequence with death being the likely outcome. Here we summarize the role of key immune cells in the repair process of the heart following left ventricular MI, along with the associated cytokines and chemokines. A better understanding of the immune response ought to lead hopefully to improved therapies that exploit the natural repair process for mending the infarcted heart. Address for Correspondence: Fouad A. Zouein, Ph.D., FAHA. Department of Pharmacology and Toxicology American University of Beirut & Medical Center Riad El-Solh 1107 2020 Beirut-Lebanon fouadzouein@outlook.com, Dina H. Muhieddine, Msc. Department of Pharmacology and Toxicology American University of Beirut & Medical Center Riad El-Solh 1107 2020 Beirut-Lebanon Dina.mehydeen@outlook.com Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved.

Point of view: Electrophysiological endpoints differ when comparing the mode of action of highly successful anti-arrhythmic drugs in the CAVB dog model with TdP. In the anaesthetized, chronic atrioventricular block (CAVB) dog, ventricular ectopic beats and Torsade de pointes arrhythmias (TdP) are believed to ensue from an abrupt prolongation of ventricular repolarization and increased temporal dispersion of repolarization, quantified as short-term variability (STV). These TdP stop spontaneously or, when supported by substantial spatial dispersion of repolarization (SDR), degenerate into ventricular fibrillation. However, most studies involving ventricular arrhythmias do not quantify SDR by means of an electrophysiological parameter. Therefore, we reviewed the effects of 4 highly effective anti-arrhythmic drugs (flunarizine, verapamil, SEA-0400 and GS-458967) on the repolarization duration and associated STV. All drugs were tested as anti-arrhythmic TdP in CAVB dogs, their high anti-arrhythmic efficacy was defined as suppressing drug-induced TdP in 100% of the experiments. This comparison demonstrates that even though the anti-arrhythmic outcome was similar for all drugs, distinct responses of repolarization duration and associated STV were observed. Moreover, the aforementioned and commonly adopted electrophysiological parameters were not always sufficient in predicting TdP susceptibility, and additional quantification of the SDR proved to be of added value in these studies. The variability in electrophysiological responses to the different anti-arrhythmic drugs and their inconsistent adequacy in reflecting TdP susceptibility, can be explained by distinct modes of interference with TdP development. As such, this overview establishes the separate involvement of temporal and spatial dispersion in ventricular arrhythmogenesis in the CAVB dog model and proposes SDR as an additional parameter to be included in future fundamental and/or pharmaceutical studies regarding TdP arrhythmogenesis. Corresponding author: Professor Marc A. Vos Yalelaan 50 3584 CM Utrecht The Netherlands Email: m.a.vos@umcutrecht.nl Telephone: +31 30 253 8900 Fax: +31 30 253 9036 No sources of support that require acknowledgement. No disclosures of funding. Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved.

Neurovascular effects of perivascular adipose tissue Regulation of sympathetic-sensory communication No abstract available

Chitosan Hydrogel Enhances the Therapeutic Efficacy of BMSCs for Myocardial Infarction by Alleviating Vascular Endothelial Cell Pyroptosis Myocardial infarction (MI) is one of the higher mortality rates, and current treatment can only delay the progression of the disease. Experiments have shown that cell therapy could improve cardiac function and mesenchymal stem cells (MSCs)-based therapies provide a great promising approach in the treatment of MI. However, low cell survival and engraftment restricts the successful application of MSCs for treating MI. Here, we explored whether co-transplantation a chitosan (CS) thermosensitive hydrogel with bone marrow-derived mesenchymal stem cells (BMSCs) could optimize and maximize the therapeutic of BMSCs in a mouse model of MI. The fate of transplanted BMSCs was monitored by bioluminescence imaging (BLI) and the recovery of cardiac function was detected by echocardiogram. Our results proved that CS hydrogel enhanced the BMSCs survival and the recovery of cardiac function by protecting the vascular endothelial cells. Further studies revealed that the increased number of vascular endothelial cells was due to the fact that transplanted BMSCs inhibited the inflammatory response and alleviated the pyroptosis of vascular endothelial cells. In conclusions, CS hydrogel improved the engraftment of transplanted BMSCs, ameliorated inflammatory responses, and further promoted functional recovery of heart by alleviating vascular endothelial cell pyroptosis. Correspondence: Weihua Zhang, M.D., Associate chief physician, Department of Cardiovascular Surgery, The First Affiliated Hospital of Zhengzhou University, 1 Jianshe East Road, Zhengzhou 450052, China, Ph: 0371-66279087, Fax: 0371-66970906, Email: zhangweihuazdyfy@163.com Conflicts of interest statement: The authors declare no conflict of interest. # These two authors contributed equally to this work. Funded by: This study was supported by the Henan Medical Science and Technology Research Project (201602064). This is an open access article distributed under the Creative Commons Attribution License 4.0 (CCBY), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved.

The effect of Cytochrome P450 7A1(CYP7A1) polymorphism on lipid responses to simvastatin treatment. Background: Identifying patients with high-risk of low-response to statin therapy is important for optimization of lipid-lowering therapy. Cholesterol 7α-hydroxylase, a rate-limiting enzyme encoded by Cytochrome P450 7A1(CYP7A1)gene, is considered to be associated with statin efficacy. This study aimed to investigate the association between a novel CYP7A1 single-nucleotide polymorphism (SNP) rs3824260 and statin treatment response for hypercholesteremic patients in Chinese Han population. Methods: A total of 336 subjects were prescribed with simvastatin for 12 weeks after enrollment. Plasma lipid parameters were measured at enrollment and after 12-weeks simvastatin treatment separately. Subjects were classified into high- and low-response groups depending on their TC, LDL-C and TG changes, and increase or reduction groups according to their HDL-C levels changing after simvastatin treatment. The CYP7A1 rs3824260 was genotyped from blood samples with a SNaPshot™ assay. Results: At baseline, the LDL-C level and TG level were significantly higher in the AA genotype, while the HDL-C level was significantly higher in the GG genotype of CYP7A1 rs3824260. Patients carrying AA genotype are at an increased risk of low-response for LDL-C reduction (OR=2.295, 95% CI=1.164-4.524, p=0.016). Furthermore, the GG genotype of rs3824260 was significantly associated with a high risk of HDL-C reduction response after simvastatin therapy (OR=2.240, 95% CI=1.137-4.413, p=0.025). Conclusions: The CYP7A1 gene polymorphism rs3824260 is related to inappropriate response of simvastatin treatment for hypercholesterolemia patients in Chinese Han population. Correspondence to: Man Zhang, M.D& Ph.D. Chief of Clinical Laboratory Medicine, Beijing Shijitan Hospital, Capital Medical University; Chief of Peking University Ninth School of Clinical Medicine; Chief of Beijing Key Laboratory of Urinary Cellular Molecular Diagnostics Address:10 Tieyi Road, Haidian District, Beijing 100038, China. TEL: 0086 10 63926389. FAX: 0086 10 63926283. E-mail: zhangman@bjsjth.cn Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved.

Ginsenoside Rb1 alleviates ox-LDL-induced vascular endothelium senescence via the SIRT1/Beclin-1/autophagy axis Oxidative low-density lipoprotein (ox-LDL) induces endothelium senescence and promotes atherosclerosis. Ginsenoside Rb1 (gRb1) has been proved to protect HUVECs, but its effect on ox-LDL induced endothelium senescence and underlying mechanism remains unknown. This study is to explore the involvement of the SIRT1/Beclin-1/autophagy axis in the effect of gRb1 on protecting endothelium against ox-LDL induced senescence. Hyperlipidemia of Sprague Dawley rats was induced by high fat diet and gRb1 was intraperitoneal injected. Senescence model of HUVECs induced by ox-LDL was also established. The results showed that gRb1 alleviated hyperlipidemia-induced endothelium senescence and ox-LDL-induced HUVECs senescence. GRb1 also restored the reductions in SIRT1 and autophagy, which were involved in the anti-senescence effects. Beclin-1 acetylation was reduced, and the correlation between SIRT1 and Beclin-1 was increased by gRb1. Results of our study demonstrated the anti-senescence function of gRb1 against hyperlipidemia in the endothelium, and the underlying mechanism involves the SIRT1/Beclin-1/autophagy axis. Corresponding Author: Jieming Zhu Department of Cardiology The Third Affiliated Hospital of Sun Yat-sen University 600 Tianhe Road Guangzhou, 510630, China Tel: +86-020-85252168 E-mail: zhujieming2011@126.com Xiaoxian Qian The Third Affiliated Hospital of Sun Yat-sen University 600 Tianhe Road Guangzhou, 510630, China Tel: +86-020-85252168 E-mail: qianxx@mail.sysu.edu.cn # These authors contributed equally to this work. Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved.

Myocardial Phosphodiesterases and their Role in cGMP Regulation Cyclic nucleotide phosphodiesterases comprise an 11-member superfamily yielding near 100 isoform variants that hydrolyze cAMP or cGMP to their respective 5’-monophosphate form. Each plays a role in compartmentalized cyclic nucleotide signaling, with varying selectivity for each substrate, and conveying cell and intracellular specific localized control. This review focuses on the five PDEs expressed in the cardiac myocyte capable of hydrolyzing cGMP and that have been shown to play a role in cardiac physiological and pathological processes. PDE1, PDE2, and PDE3 catabolize cAMP as well, whereas PDE5 and PDE9 are cGMP selective. PDE3 and PDE5 are already in clinical use, the former for heart failure, and PDE1, PDE9, and PDE5 are all being actively studied for this indication in patients. Research in just the past few years has revealed many novel cardiac influences of each isoform, expanding the therapeutic potential from their selective pharmacological blockade or in some instances, activation. PDE1C inhibition was found to confer cell survival protection and enhance cardiac contractility, while PDE2 inhibition or activation induces beneficial effects in hypertrophied or failing hearts, respectively. PDE3 inhibition is already clinically employed to treat acute decompensated heart failure, though toxicity has precluded its long-term use. However, newer approaches including isoform specific allosteric modulation may change this. Lastly, inhibition of PDE5A and PDE9A counter pathological remodeling of the heart and are both being pursued in clinical trials. Here we discuss recent research advances in each of these PDEs, their impact on the myocardium, and cardiac therapeutic potential. Address Correspondence: David A. Kass, M.D. Ross Research Building , Room 858 Johns Hopkins Medical Institutions 720 Rutland Avenue Baltimore, MD 21205 (410) 955-7153 dkass@jhmi.edu Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved.

CD137-CD137L signaling affects angiogenesis by mediating phenotypic conversion of macrophages Background: Angiogenesis in atherosclerotic plaque is an important factor causing plaque hemorrhage, vulnerability and rupture and different phenotypes of macrophages have different effects on angiogenesis. Our previous study has demonstrated CD137-CD137L signaling, a pair of inflammatory co-stimulatory molecules, can promote angiogenesis in atherosclerotic plaque. Therefore, we aimed to investigate whether this signaling could affect angiogenesis by regulating phenotypic transition of macrophages. Methods: Male mouse primary peritoneal macrophages were extracted by intraperitoneal injection of thioglycollate, and then flow cytometry was used to detect the expression of CD137. Flow cytometry, Western blotting, quantitative real-time PCR and enzyme-linked immunosorbent assay (ELISA) were used to assess the phenotypic changes of macrophages after different treatment. Mouse brain microvascular endothelial cells (bEnd.3) were co-cultured with macrophages and tube formation was assessed to examine angiogenesis. Results: We found that the number of junctions and branches of bEnd.3 were increased when CD137-CD137L signaling was activated, while such number was further increased when bEnd.3 were co-cultured with macrophages. Flow cytometry showed that CD137 was expressed on almost all primary peritoneal macrophages. The expression of CD86 was decreased in the agonist CD137L group and increased in the agonist CD137L + inhibitory anti-CD137 antibody group after adding the CD137 inhibitor. The expression of CD206 in each group exhibited opposite trend compared with CD86. Moreover, the expression of inducible nitric oxide synthase (iNOS) at the mRNA and protein levels was decreased after stimulating CD137-CD137L signaling, and such downward trend was reversed when CD137-CD137L signaling was inhibited. Furthermore, the expression of arginase-1 was opposite to that of iNOS. ELISA indicated that the content of interleukin-12 (IL-12) in the supernatant of macrophages in the agonist CD137L group was lower than that in the control group, and its content in the inhibited group was higher than that in the activated group. The change of interleukin-10 (IL-10) content in macrophage supernatant was opposite to that of IL-12. When AKT serine/threonine kinase 1 (Akt1) inhibitor was used to inhibit the phenotypic transformation of macrophages induced by CD137-CD137L, the number of junctions and branches formed by bEnd.3 was decreased compared with the co-culture group. Conclusions: These results indicated that CD137-CD137L signaling could promote angiogenesis by regulating phenotypic transition of macrophages of male mice. Corresponding author: E-mail:yanjinchuan@hotmail.com * These authors contributed equally to this work. This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CCBY-NC-ND), where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially without permission from the journal. Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved.

Therapeutic implications of nitrite in hypertension Nitrite, an anion produced from the oxidative breakdown of nitric oxide (NO) has traditionally been viewed as an inert molecule. However, this dogma has been challenged with the findings that nitrite can be readily reduced to NO under pathological conditions, hence representing a physiologically relevant storage reservoir of NO either in the blood or tissues. Nitrite administration has been demonstrated to improve myocardial function in subjects with heart failure and to lower the blood pressure in hypertensive subjects. Thus, extensive amount of work has since been carried out to investigate the therapeutic potential of nitrite in treating cardiovascular diseases, especially hypertension. Studies done on several animal models of hypertension have demonstrated the efficacy of nitrite in preventing and ameliorating the pathological changes associated with the disease. This brief review of the current findings aims to re-evaluate the use of nitrite for the treatment of hypertension and in particular to highlight its role in improving endothelial function. Corresponding Author: Dharmani Devi Murugan, Department of Pharmacology, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia, Email address: dharmani79@um.edu.my Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved.

Perivascular adipose tissue modulation of neurogenic vasorelaxation of rat mesenteric arteries Perivascular sympathetic-sensory interactions have been shown to regulate calcitonin gene-related peptide (CGRP)-mediated vasodilation in rats. We investigated whether perivascular adipose tissue (PVAT) modulates the neurogenic vasorelaxation of isolated rat mesenteric arteries. Mesenteric arterial rings were prepared with or without PVAT (PVAT+ or PVAT−) and with either an intact or denuded endothelium (EC+ or EC-). The results of myography analysis revealed that vasocontraction to phenylephrine was highest in EC-PVAT-, lowest in EC+PVAT+, and intermediate in EC-PVAT+ and EC+PVAT-. Transmural nerve stimulation (TNS) induced the tetrodotoxin-sensitive relaxation of the phenylephrine-precontracted mesenteric arteries. However, nicotine induced minor relaxation in EC-PVAT+, while vasorelaxation was significantly enhanced in EC-PVAT-. Nicotine-induced vasorelaxation was insensitive to propranolol and also significantly lower in sympathetically-denervated and guanethidine-treated EC-PVAT-, while TNS-induced vasorelaxation persisted. In EC-PVAT- depleted of CGRP via capsaicin, nicotine- and TNS-induced vasorelaxation was almost absent. Lowering the pH of Krebs’ solution using HCl led to pH-dependent vasorelaxation that was sensitive to CGRP8-37. Furthermore, nicotine-induced relaxation of EC-PVAT-, which was not affected by leptin, was blocked by methyl palmitate. Methyl palmitate did not affect TNS- or HCl-induced vasorelaxation. These results suggest that PVAT plays a modulatory role in regulating sympathetic-sensory interaction-mediated CGRPergic vasorelaxation via the release of methyl palmitate. Corresponding Author: Shang-Jen Chang, MD, MS, Taipei Tzu Chi Hospital, New Taipei,, TAIWAN E-mail: changhh@livemail.tw, E-mail: urolyang@tzuchi.com.tw, E-mail: krissygnet@yahoo.com.tw Sources of funding: This work was supported by grants from Taipei Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation (TCRD-TPE-106-RT-6 and TCRD-TPE-107-51). Disclosures: No conflicts of interest, financial or otherwise, are declared by the authors. Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved.