Pannexin 1 Modulates Angiogenic Activities of Human Endothelial Colony-Forming Cells Through IGF-1 Mechanism and Is a Marker of Senescence.

BACKGROUND: We examined the role of Panxs (pannexins) in human endothelial progenitor cell (EPC) senescence. METHODS: Young and replication-induced senescent endothelial colony-forming cells (ECFCs) derived from human circulating EPCs were used to examine cellular activities and senescence-associated indicators after transfection of short interference RNA specific to Panx1 or lentivirus-mediated Panx1 overexpression. Hind limb ischemia mice were used as in vivo angiogenesis model. Protein and phospho-kinase arrays were used to determine underlying mechanisms. RESULTS: Panx1 was the predominant Panx isoform in human ECFCs and upregulated in both replication-induced senescent ECFCs and circulating EPCs from aged mice and humans. Cellular activities of the young ECFCs were enhanced by Panx1 downregulation but attenuated by its upregulation. In addition, reduction of Panx1 in the senescent ECFCs could rejuvenate cellular activities with reduced senescence-associated indicators, including senescence-associated ß-galactosidase activity, p16INK4a (cyclin-dependent kinase inhibitor 2A), p21 (cyclin-dependent kinase inhibitor 1), acetyl-p53 (tumor protein P53), and phospho-histone H2A.X (histone family member X). In mouse ischemic hind limbs injected senescent ECFCs, blood perfusion ratio, salvaged limb outcome, and capillary density were all improved by Panx1 knockdown. IGF-1 (insulin-like growth factor 1) was significantly increased in the supernatant from senescent ECFCs after Panx1 knockdown. The enhanced activities and paracrine effects of Panx1 knockdown senescent ECFCs were completely inhibited by anti-IGF-1 antibodies. FAK (focal adhesion kinase), ERK (extracellular signal-regulated kinase), and STAT3 (signal transducer and activator of transcription 3) were activated in senescent ECFCs with Panx1 knockdown, in which the intracellular calcium level was reduced, and the activation was inhibited by supplemented calcium. The increased IGF-1 in Panx1-knockdown ECFCs was abrogated, respectively, by inhibitors of FAK (PF562271), ERK (U0126), and STAT3 (NSC74859) and supplemented calcium. CONCLUSIONS: Panx1 expression is upregulated in human ECFCs/EPCs with replication-induced senescence and during aging. Angiogenic potential of senescent ECFCs is improved by Panx1 reduction through increased IGF-1 production via activation of the FAK-ERK axis following calcium influx reduction. Our findings provide new strategies to evaluate EPC activities and rejuvenate senescent EPCs for therapeutic angiogenesis.

2022 Taiwan lipid guidelines for primary prevention.

Elevated circulating low-density lipoprotein cholesterol (LDL-C) is a major risk factor of atherosclerotic cardiovascular disease (ASCVD). Early control of LDL-C to prevent ASCVD later in life is important. The Taiwan Society of Lipids and Atherosclerosis in association with the other seven societies developed this new lipid guideline focusing on subjects without clinically significant ASCVD. In this guideline for primary prevention, the recommended LDL-C target is based on risk stratification. A healthy lifestyle with recommendations for foods, dietary supplements and alcohol drinking are described. The pharmacological therapies for LDL-C reduction are recommended. The aim of this guideline is to decrease the risk of ASCVD through adequate control of dyslipidemia in Taiwan.

Histological evidence of chitosan-encapsulated curcumin suppresses heart and kidney damages on streptozotocin-induced type-1 diabetes in mice model.

High blood glucose in diabetic patients often causes cardiovascular diseases (CVDs) that threats to human life. Curcumin (Cur) is known as an antioxidant agent, possesses anti-inflammatory activity, and prevents CVDs. However, the clinical application of curcumin was limited due to its low bioavailability. This study aimed to investigate the ameliorative effects of chitosan-encapsulated curcumin (CEC) on heart and kidney damages in streptozotocin-induced type-1 diabetes C57BL/6 mice model. The results showed that Cur- and CEC-treatments downregulated the blood sugar and total cholesterol level as well as enhanced insulin secretion. However, blood pressure, triglycerides content, and very low-density lipoprotein-cholesterol content were not changed. Histochemistry analysis revealed that both curcumin and chitosan-encapsulated curcumin ameliorated cell hypertrophy and nucleus enlargement in the left ventricular of heart and reduced fibrosis in the kidney, especially after the chitosan-encapsulated curcumin treatment. Our study suggested that chitosan can effectively enhance the protective effect of curcumin on the heart and kidney damages in type-1 diabetes mice model.

Mitochondrial fission protein 1 up-regulation ameliorates senescence-related endothelial dysfunction of human endothelial progenitor cells.

BACKGROUND: We investigated the contribution of mitochondrial dysfunction to the senescence of human endothelial progenitor cells (EPCs) expanded in vitro and the underlying molecular mechanism. METHODS AND RESULTS: Serial passage increased cell doubling time and those cells reaching the doubling time for more than 100% were defined as senescent EPCs, of which the activity of therapeutic angiogenesis was attenuated in mouse ischemic hindlimbs. The senescent cells, in medium free of glucose and bicarbonate, showed impaired activity in migration and tube formation. Flow cytometry indicated increased content of reactive oxygen species, mitochondria, and calcium, while bioenergetic analysis showed increased oxygen consumption and reduced ATP content. Examination of mitochondrial network showed that senescence increased the length of the network and ultrastructure analysis exhibited elongated mitochondria. Immunoblotting of the senescent EPCs demonstrated decreased expression level of fission protein1 (Fis1). In rat EPCs, the Fis1 level was decreased in the animals aged 24 months or older, compared to those of 3 months. Silencing of Fis1 in the young EPCs using Fis1-specific siRNA leads to appearance of phenotype resembling those of senescent cells, including elevated oxidative stress, disturbed mitochondrial network, reduced mitochondria membrane potential, decreasing ATP content, lower proliferation activity, and loss of therapeutic potential in ischemic hindlimbs. Fis1 over-expression in senescent EPCs reduced the oxidative stress, increased the proliferation, and restored the cobble stone-like morphology, senescence, bioenergetics, angiogenic potential, and therapeutic activity. CONCLUSION: In human EPCs, down-regulation of Fis1 is involved in mitochondrial dysfunction and contributes to the impaired activity of EPCs during the senescence process. Enhanced expression of Fis1 in senescent EPCs restores the youthful phenotype.

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.

Butein Inhibits Angiogenesis of Human Endothelial Progenitor Cells via the Translation Dependent Signaling Pathway.

Compelling evidence indicates that bone marrow-derived endothelial progenitor cells (EPCs) can contribute to postnatal neovascularization and tumor angiogenesis. EPCs have been shown to play a "catalytic" role in metastatic progression by mediating the angiogenic switch. Understanding the pharmacological functions and molecular targets of natural products is critical for drug development. Butein, a natural chalcone derivative, has been reported to exert potent anticancer activity. However, the antiangiogenic activity of butein has not been addressed. In this study, we found that butein inhibited serum- and vascular endothelial growth factor- (VEGF-) induced cell proliferation, migration, and tube formation of human EPCs in a concentration dependent manner without cytotoxic effect. Furthermore, butein markedly abrogated VEGF-induced vessels sprouting from aortic rings and suppressed microvessel formation in the Matrigel implant assay in vivo. In addition, butein concentration-dependently repressed the phosphorylation of Akt, mTOR, and the major downstream effectors, p70S6K, 4E-BP1, and eIF4E in EPCs. Taken together, our results demonstrate for the first time that butein exhibits the antiangiogenic effect both in vitro and in vivo by targeting the translational machinery. Butein is a promising angiogenesis inhibitor with the potential for treatment of cancer and other angiogenesis-related diseases.

Heart failure enhances arrhythmogenesis in pulmonary veins.

1. Heart failure (HF) predisposes to atrial fibrillation (AF) as a result of substrate remodelling. The present study aimed to investigate the impact of HF on the electrical remodelling of the pulmonary veins (PV) and left atrium (LA). 2. The electrical activity was recorded in LA and PV from control rabbits and rabbits with rapid ventricular pacing-induced HF, using a multi-electrode array system and conventional microelectrodes. 3. Compared with the control-PV (n = 21), the HF-PV (n = 13) had a higher incidence and frequency of rapid pacing-induced spontaneous activity (85 vs 29%, P = 0.005; 3.5 ± 0.2 vs 1.7 ± 0.1 Hz, P < 0.001) and high-frequency irregular electrical activity (92 vs 38%, P = 0.01; 23 ± 1 vs 19 ± 1 Hz, P = 0.003), greater depolarized resting membrane potential (-59 ± 1 vs -70 ± 2 mV, P < 0.001), higher incidence of early afterdepolarizations (EAD; 69 vs 6%, P = 0.001) and delayed afterdepolarizations (DAD; 92 vs 25%, P = 0.001), and slower conduction velocity (38 ± 2 vs 63 ± 2 cm/s, P < 0.05). In comparison to the HF-LA, the HF-PV had a higher incidence of spontaneous activity and high-frequency irregular electrical activity (85 vs 39%, P = 0.04; 92 vs 46%, P = 0.03), and higher incidence of EAD and DAD, and those differences were not found between the control-LA and control-PV. The control-PV with high-frequency irregular electrical activity had a higher incidence of DAD and spontaneous activity as compared with those without it. 4. HF contributed to an increased automaticity, triggered activity and conduction disturbance in the PV. The PV possessed more arrhythmogenic properties, which might play an important role in the genesis of AF in HF.

On the mechanisms of arrhythmias in the myocardium of mXinalpha-deficient murine left atrial-pulmonary veins.

We have previously shown that left atrial-pulmonary vein tissue (LA-PV) can generate reentrant arrhythmias (atrial fibrillation, AF) in wild-type (mXinalpha+/+) but not in mXinalpha-null (mXinalpha-/-) mice. With the present experiments, we investigated the arrhythmogenic activity and the underlying mechanisms in mXinalpha+/+ vs. mXinalpha-/- LA-PV. Electrical activity and conduction velocity (CV) were recorded in LA-PV by means of a MED64 system. CV was significantly faster in mXinalpha+/+ than in mXinalpha-/- LA-PV and it was increased by 1 muM isoproterenol (ISO). AF could be induced by fast pacing in the mXinalpha+/+ but not in mXinalpha-/- LA-PV where automatic rhythms could occur. ISO increased the incidence of AF in Xinalpha+/+ whereas it increased that of automatic rhythms in mXinalpha-/- LA-PV. In LA-PV with the right atrium attached (RA-LA-PV), automatic rhythms occurred in all preparations. In mXinalpha+/+ RA-LA-PV simultaneously treated with ISO, strophanthidin and atropine, the incidence of the automatic rhythm was about the same, but AF increased significantly. In contrast, in mXinalpha-/- RA-LA-PV under the same condition, the automatic rhythm was markedly enhanced, but still no AF occurred. Conventional microelectrode techniques showed a longer APD(90) and a less negative maximum diastolic potential (MDP) in mXinalpha-/- than mXinalpha+/+ LA-PV tissues. Whole-cell current clamp experiments also showed a less negative MDP in mXinalpha-/- vs. mXinalpha+/+ LA-PV cardiomyocytes. The fact that AF could be induced by fast pacing under several conditions in mXinalpha+/+ but not in mXinalpha-/- LA-PV preparations appears to be due to a slower CV, a prolonged APD(90), a less negative MDP and possibly larger areas of conduction block in mXinalpha-/- myocardial cells. In contrast, the non-impairment of automatic and triggered rhythms in mXinalpha-/- preparations may be due to the fact that the mechanisms underlying these rhythms do not involve cell-to-cell conduction.

C-type natriuretic peptide in individuals with normal left ventricular systolic function.

OBJECTIVE: The objective of this study was to evaluate production or release of CNP in individuals without CHF. METHODS: Nineteen patients with symptomatic paroxysmal supraventricular tachycardia (PSVT) and normal left ventricular systolic function were enrolled into the study. Blood samples were collected from the coronary sinus (CS), the femoral artery (FA), and the peripheral vein (PV) before pacing, after rapid RA pacing, and post electrophysiological study (EPS) and/or radiofrequency (RF) ablation. RESULTS: The CNP level in the CS, compared to FA and PV, was significantly higher before pacing (CS, 3.2+/-0.8; FA, 2.6+/-0.7; PV, 2.5+/-0.5 pg/ml; CS vs. either FA or PV, both p<0.001), after the pacing (CS, 3.2+/-1.3; FA, 2.4+/-0.6 pg/ml; p=0.004), and post the EPS and/or RF ablation (CS, 3.1+/-0.7; FA, 2.6+/-0.9; PV, 2.5+/-0.8 pg/ml; CS vs. either FA or PV, both p<0.01). CONCLUSION: The myocardium regularly produces or releases CNP in patients with normal LV systolic function. Brief periods of rapid RA pacing, PSVT, or EPS does not change the production and/or release.

Antioxidant effects of black rice extract through the induction of superoxide dismutase and catalase activities.

Our ex vivo study revealed that BRE had significantly stronger ability to inhibit LDL oxidation than white rice extract (WRE). The purpose of this study was to investigate whether black rice extract (BRE) supplementation might ameliorate oxidative stress and enhance antioxidant enzyme activities in HepG2 cells and in C57BL/6 mice. In the cellular study, superoxide anions (O2*-) and reactive oxygen species (ROS) in the BRE group were significantly suppressed. The BRE group also showed significant increases in superoxide dismutase (SOD) and catalase (CAT) activities by 161.6% and 73.4%, respectively. The major components responsible for the free-radical-scavenging and antioxidative properties might be cyanidin-3-O-glucoside chloride and peonidin-3-O-glucuside chloride. In the animal study, male C57BL/6 mice were divided into three groups (control, BRE, and WRE). Plasma HDL-cholesterol was significantly higher, and thiobarbituric, acid-reactive substances were significantly lower in the BRE group, whereas plasma levels of total cholesterol and triglyceride were not affected by BRE supplementation. Increased hepatic SOD and CAT activities were observed in BRE-treated mice as compared to the control mice. However, no changes were detected for the protein expression of antioxidant enzymes by Western blot analysis. Our data suggest that antioxidative effects exerted by BRE are mediated through decreases in free-radical generation as well as increases in SOD and CAT activities both in vitro and in vivo.

Electrophysiology and arrhythmogenic activity of single cardiomyocytes from canine superior vena cava.

BACKGROUND: The superior vena cava (SVC) has been proved to be a focal point in the initiation of paroxysmal atrial fibrillation. The autonomic nervous system plays an important role in the genesis of atrial fibrillation. However, the arrhythmogenic potentials of SVC and its responses to autonomic agents are not clear. The purpose of this study was to isolate single SVC cardiomyocytes and to investigate their electrophysiological characteristics, as well as the direct effects of autonomic agents. METHODS AND RESULTS: Canine SVC cardiomyocytes were isolated by perfusion with digestive enzymes. The action potentials and ionic currents were investigated in single SVC cardiomyocytes using the whole-cell clamp technique. Dissociation of the SVC yielded rod-shaped single cardiomyocytes with (n=74, 51%) or without (n=71, 49%) pacemaker activities. There were similar densities of inward Ca2+, delayed rectifier K+, transient inward, inward rectifier K+, and pacemaker currents between SVC cardiomyocytes with and without pacemaker activity. SVC cardiomyocytes with pacemaker activity have, however, greater transient outward currents than those without pacemaker activity. In SVC cardiomyocytes, acetylcholine (5.5 micromol/L) abolished the spontaneous activities, but isoproterenol (10 nmol/L), atropine (10 micromol/L), and phenylephrine (10 micromol/L) accelerated the spontaneous activity and induced the occurrences of early or delayed afterdepolarizations. CONCLUSIONS: These findings suggest that SVC cardiomyocytes have distinct action potentials and ionic current profiles that may be responsible for the arrhythmogenic activity of the SVC.