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1.
Des Monomers Polym ; 26(1): 182-189, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37426067

RESUMEN

Various transition metal catalysts have been utilized for ethylene polymerization. Silver catalysts have attracted less attention as the catalysts, but are potential for production of high molecular weight polyethylene. Herein, we report that silver complexes with various N-heterocyclic carbene (NHC) ligands in combination with modified methylaluminoxane (MMAO) afford polyethylene with high molecular weight (melting point over 140°C). SEM observation showed that the produced polyethylene has ultra-high molecular weight. NMR investigation of the reaction between the silver complexes with organoaluminums indicate that the NHC ligands transfer from the silver complex to aluminum to produce NHC aluminum complexes. Ph3C[B(C6F5)4] abstract methyl group from the NHC aluminum complex to afford cationic aluminum complex. The NHC aluminum complex promoted ethylene polymerization in the presence of Ph3C[B(C6F5)4] and organoaluminums. NHC ligand also promoted ethylene polymerization in combination with MMAO to produce polyethylene with high melting point (140.7°C). Thus, the aluminum complexes are considered to be the actual active species in silver-catalyzed ethylene polymerization.

2.
Kidney Int ; 98(5): 1242-1252, 2020 11.
Artículo en Inglés | MEDLINE | ID: mdl-32592815

RESUMEN

To investigate the cause of salt sensitivity in a normotensive animal model, we treated rats with a low-dose of the nitric oxide synthase inhibitor, L-NAME, that does not elevate blood pressure per se or induce kidney fibrosis. A high salt diet increased the circulating blood volume both in L-NAME-treated and nontreated animals for the first 24 hours. Thereafter, the blood volume increase persisted only in the L-NAME-treated rats. Blood pressure was higher in the L-NAME-treated group from the start of high salt diet exposure. Within the first 24 hours of salt loading, the L-NAME treated animals failed to show vasodilation and maintained high systemic vascular resistance in response to blood volume expansion. After four weeks on the high salt diet, the slope of the pressure-natriuresis curve was blunted in the L-NAME-treated group. An increase in natriuresis was observed after treatment with hydrochlorothiazide, but not amiloride, a change observed in parallel with increased phosphorylated sodium-chloride cotransporter (NCC). In contrast, a change in blood pressure was not observed in L-NAME-treated NCC-deficient mice fed a high salt diet. Moreover, direct L-NAME-induced NCC activation was demonstrated in cells of the mouse distal convoluted tubule. The vasodilatator, sodium nitroprusside, downregulated phosphorylated NCC expression. The effect of L-NAME on phosphorylated NCC was blocked by both the SPAK inhibitor STOCK2S-26016 and the superoxide dismutase mimetic TEMPO which also attenuated salt-induced hypertension. These results suggest that the initiation of salt sensitivity in normotensive rodents could be due to hyporeactivity of the vasculature and that maintaining blood pressure could result in a high circulating volume due to inappropriate NCC activity in the low-dose L-NAME model. Thus, even slightly impaired nitric oxide production may be important in salt sensitivity regulation in healthy rodents.


Asunto(s)
Hipertensión , Simportadores del Cloruro de Sodio , Animales , Presión Sanguínea , Volumen Sanguíneo , Hipertensión/inducido químicamente , Ratones , NG-Nitroarginina Metil Éster , Ratas , Roedores
3.
Hypertens Res ; 42(5): 699-707, 2019 05.
Artículo en Inglés | MEDLINE | ID: mdl-30626932

RESUMEN

Hypertensive disorders of pregnancy (HDP) represent a frequent disorder among pregnancies. Women with severe hypertension in pregnancy are at increased risk of maternal complications and require antihypertensive drug therapy. This study aimed to systematically review randomized control trials of antihypertensive drug(s) treating non-severe hypertension during pregnancy to estimate the effectiveness and safety of this intervention. On May 8, 2018, we searched PubMed, Cochrane Library, and Ichu-Shi with no restriction on publication year. We selected randomized control trials that involved women with HDP being treated with antihypertensive drug(s) as intervention. Fourteen trials (1804 women) were identified for meta-analysis. There were no significant differences in the risk of maternal death (373 women; risk ratio (RR) 0.70; 95% confidence interval (CI) 0.04 to 11.45), proteinuria (1214 women; RR 1.00; 95% CI 0.67 to 1.49), side effects (360 women; RR 2.69; 95% CI 0.32 to 22.64), cesarean section (1239 women; RR 0.97; 95% CI 0.82 to 1.15), neonatal and birth death (1548 women; RR 0.80; 95% CI 0.43 to 1.49), preterm birth (904 women; RR 0.86; 95% CI 0.53 to 1.39), or small for gestational age infants (1082 women; RR 1.04; 95% CI 0.66 to 1.63) with antihypertensive drug therapy versus placebo or no treatment. The current review suggests that antihypertensive drug therapy does not reduce or increase the risk of maternal or perinatal outcomes. Further studies are needed to build reliable estimates of the effectiveness and safety of antihypertensive drug therapy for women with HDP.


Asunto(s)
Antihipertensivos/uso terapéutico , Hipertensión Inducida en el Embarazo/tratamiento farmacológico , Femenino , Humanos , Embarazo , Resultado del Embarazo , Ensayos Clínicos Controlados Aleatorios como Asunto , Resultado del Tratamiento
4.
Ann N Y Acad Sci ; 1443(1): 34-53, 2019 05.
Artículo en Inglés | MEDLINE | ID: mdl-30381837

RESUMEN

LOX-1 (lectin-like oxidized low-density lipoprotein receptor-1; also known as OLR1) is the dominant receptor that recognizes and internalizes oxidized low-density lipoproteins (ox-LDLs) in endothelial cells. Several genetic variants of LOX-1 are associated with the risk and severity of coronary artery disease. The LOX-1-ox-LDL interaction induces endothelial dysfunction, leukocyte adhesion, macrophage-derived foam cell formation, smooth muscle cell proliferation and migration, and platelet activation. LOX-1 activation eventually leads to the rupture of atherosclerotic plaques and acute cardiovascular events. In addition, LOX-1 can be cleaved to generate soluble LOX-1 (sLOX-1), which is a useful diagnostic and prognostic marker for atherosclerosis-related diseases in human patients. Of therapeutic relevance, several natural products and clinically used drugs have emerged as LOX-1 inhibitors that have antiatherosclerotic actions. We hereby provide an updated overview of role of LOX-1 in atherosclerosis and associated vascular diseases, with an aim to highlighting the potential of LOX-1 as a novel theranostic tool for cardiovascular disease prevention and treatment.


Asunto(s)
Aterosclerosis/tratamiento farmacológico , Enfermedad de la Arteria Coronaria/tratamiento farmacológico , Receptores Depuradores de Clase E/efectos de los fármacos , Biomarcadores/metabolismo , Humanos , Factores de Riesgo , Receptores Depuradores de Clase E/genética , Receptores Depuradores de Clase E/metabolismo
6.
Clin Chim Acta ; 457: 142-9, 2016 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-27101813

RESUMEN

BACKGROUND: Voided urine contains a variety of cells from the kidney and urinary tract and urinalysis provides us various information by investigating cellular components. We investigated urine sediment from renal impaired patients. RESULTS: We found 'round cell' to be distinct from known cells in sediment and is close to proximal convoluted tubule-derived cells based on morphology and molecular marker expression (GGT1 but not podocalyxin). Also it was positive for undifferentiated cell markers, including PAX2, WT1, OSR1, and SIX2. They were observed in end-stage renal failure patients and the number of cells was correlated with the severity of chronic kidney disease. A prospective analysis revealed that patients who had more round cells were more likely to require hemodialysis within a year. CONCLUSION: Round cells are a novel marker that can be used to predict the need for hemodialysis.


Asunto(s)
Urinálisis , Orina/citología , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Masculino , Persona de Mediana Edad
7.
PLoS One ; 10(7): e0131923, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-26132492

RESUMEN

Chronic intermittent hypoxia (IH) induces activation of the sympathoadrenal system, which plays a pivotal role in attenuating hypoxic pulmonary vasoconstriction (HPV) via central ß1-adrenergic receptors (AR) (brain) and peripheral ß2AR (pulmonary arteries). Prolonged hypercatecholemia has been shown to upregulate ß3AR. However, the relationship between IH and ß3AR in the modification of HPV is unknown. It has been observed that chronic stimulation of ß3AR upregulates inducible nitric oxide synthase (iNOS) in cardiomyocytes and that IH exposure causes expression of iNOS in RAW264.7 macrophages. iNOS has been shown to have the ability to dilate pulmonary vessels. Hence, we hypothesized that chronic IH activates ß3AR/iNOS signaling in pulmonary macrophages, leading to the promotion of NO secretion and attenuated HPV. Sprague-Dawley rats were exposed to IH (3-min periods of 4-21% O2) for 8 h/d for 6 weeks. The urinary catecholamine concentrations of IH rats were high compared with those of controls, indicating activation of the sympathoadrenal system following chronic IH. Interestingly, chronic IH induced the migration of circulating monocytes into the lungs and the predominant increase in the number of pro-inflammatory pulmonary macrophages. In these macrophages, both ß3AR and iNOS were upregulated and stimulation of the ß3AR/iNOS pathway in vitro caused them to promote NO secretion. Furthermore, in vivo synchrotron radiation microangiography showed that HPV was significantly attenuated in IH rats and the attenuated HPV was fully restored by blockade of ß3AR/iNOS pathway or depletion of pulmonary macrophages. These results suggest that circulating monocyte-derived pulmonary macrophages attenuate HPV via activation of ß3AR/iNOS signaling in chronic IH.


Asunto(s)
Hipoxia/metabolismo , Pulmón/metabolismo , Macrófagos Alveolares/metabolismo , Óxido Nítrico Sintasa de Tipo II/metabolismo , Arteria Pulmonar/metabolismo , Animales , Hipertensión Pulmonar/metabolismo , Miocitos Cardíacos/metabolismo , Ratas , Ratas Sprague-Dawley , Vasoconstricción/fisiología
8.
Lipids Health Dis ; 14: 6, 2015 Feb 13.
Artículo en Inglés | MEDLINE | ID: mdl-25888871

RESUMEN

BACKGROUND: It is widely known that salt is an accelerating factor for the progression of metabolic syndrome and causes cardiovascular diseases, most likely due to its pro-oxidant properties. We hypothesized that excessive salt intake also facilitates the development of nonalcoholic steatohepatitis (NASH), which is frequently associated with metabolic syndrome. METHODS: We examined the exacerbating effect of high-salt diet on high-fat diet-induced liver injury in a susceptible model to oxidative stress, apoE knockout and lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) transgenic mice. RESULTS: High-salt diet led to NASH in high-fat diet-fed LOX-1 transgenic/apoE knockout mice without affecting high-fat diet-induced dyslipidemia or hepatic triglyceride accumulation. Additionally, a high-salt and high-fat diet stimulated oxidative stress production and inflammatory reaction to a greater extent than did a high-fat diet in the liver of LOX-1 transgenic/apoE knockout mice. CONCLUSIONS: We demonstrated that high-salt diet exacerbated NASH in high-fat diet-fed LOX-1 transgenic /apoE knockout mice and that this effect was associated with the stimulation of oxidative and inflammatory processes; this is the first study to suggest the important role of excessive salt intake in the development of NASH.


Asunto(s)
Dieta Alta en Grasa/efectos adversos , Dislipidemias/complicaciones , Hígado Graso/etiología , Estrés Oxidativo/efectos de los fármacos , Sodio en la Dieta/efectos adversos , Animales , Western Blotting , Dislipidemias/patología , Hígado Graso/patología , Fibrosis/etiología , Inflamación/etiología , Hígado/química , Hígado/patología , Masculino , Ratones , Ratones Noqueados , NADP/metabolismo , Estrés Oxidativo/fisiología , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Receptores Depuradores de Clase E/biosíntesis , Receptores Depuradores de Clase E/genética , Superóxidos/análisis
9.
Am J Respir Cell Mol Biol ; 53(2): 184-92, 2015 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-25490411

RESUMEN

Pulmonary arterial hypertension (PAH) is prevalent in patients with obstructive sleep apnea syndrome (OSAS). Aging induces arginase activation and reduces nitric oxide (NO) production in the arteries. Intermittent hypoxia (IH), conferred by cycles of brief hypoxia and normoxia, contributes to OSAS pathogenesis. Here, we studied the role of arginase and aging in the pathogenesis of PAH in adult (9-mo-old) and young (2-mo-old) male Sprague-Dawley rats subjected to IH or normoxia for 4 weeks and analyzed them with a pressure-volume catheter inserted into the right ventricle (RV) and by pulsed Doppler echocardiography. Western blot analysis was conducted on arginase, NO synthase isoforms, and nitrotyrosine. IH induced PAH, as shown by increased RV systolic pressure and RV hypertrophy, in adult rats but not in young rats. IH increased expression levels of arginase I and II proteins in the adult rats. IH also increased arginase I expression in the pulmonary artery endothelium and arginase II in the pulmonary artery adventitia. Furthermore, IH reduced pulmonary levels of nitrate and nitrite but increased nitrotyrosine levels in adult rats. An arginase inhibitor (N(ω)-hydroxy-nor-1-arginine) prevented IH-induced PAH and normalized nitrite and nitrate levels in adult rats. IH induced arginase up-regulation and PAH in adult rats, but not in young rats, through reduced NO production. Our findings suggest that arginase inhibition prevents or reverses PAH.


Asunto(s)
Arginasa/metabolismo , Hipertensión/enzimología , Envejecimiento , Animales , Hipoxia de la Célula , Activación Enzimática , Pulmón/enzimología , Masculino , Nitratos/metabolismo , Óxido Nítrico Sintasa de Tipo I/metabolismo , Óxido Nítrico Sintasa de Tipo III/metabolismo , Nitritos/metabolismo , Arteria Pulmonar/enzimología , Arteria Pulmonar/fisiopatología , Ratas Sprague-Dawley , Tirosina/análogos & derivados , Tirosina/metabolismo
10.
PLoS One ; 9(10): e110693, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-25350545

RESUMEN

In sleep apnea syndrome (SAS), intermittent hypoxia (IH) induces repeated episodes of hypoxic pulmonary vasoconstriction (HPV) during sleep, which presumably contribute to pulmonary arterial hypertension (PAH). However, the prevalence of PAH was low and severity is mostly mild in SAS patients, and mild or no right ventricular hypertrophy (RVH) was reported in IH-exposed animals. The question then arises as to why PAH is not a universal finding in SAS if repeated hypoxia of sufficient duration causes cycling HPV. In the present study, rats underwent IH at a rate of 3 min cycles of 4-21% O2 for 8 h/d for 6 w. Assessment of diameter changes in small pulmonary arteries in response to acute hypoxia and drugs were performed using synchrotron radiation microangiography on anesthetized rats. In IH-rats, neither PAH nor RVH was observed and HPV was strongly reversed. Nadolol (a hydrophilic ß(1, 2)-blocker) augmented the attenuated HPV to almost the same level as that in N-rats, but atenolol (a hydrophilic ß1-blocker) had no effect on the HPV in IH. These ß-blockers had almost no effect on the HPV in N-rats. Chronic administration of nadolol during 6 weeks of IH exposure induced PAH and RVH in IH-rats, but did not in N-rats. Meanwhile, atenolol had no effect on morphometric and hemodynamic changes in N and IH-rats. Protein expression of the ß1-adrenergic receptor (AR) was down-regulated while that of ß2AR was preserved in pulmonary arteries of IH-rats. Phosphorylation of p85 (chief component of phosphoinositide 3-kinase (PI3K)), protein kinase B (Akt), and endothelial nitric oxide synthase (eNOS) were abrogated by chronic administration of nadolol in the lung tissue of IH-rats. We conclude that IH-derived activation of ß2AR in the pulmonary arteries attenuates the HPV, thereby preventing progression of IH-induced PAH. This protective effect may depend on the ß2AR-Gi mediated PI3K/Akt/eNOS signaling pathway.


Asunto(s)
Hipertensión Pulmonar/metabolismo , Hipertensión Pulmonar/fisiopatología , Hipoxia/metabolismo , Arteria Pulmonar/metabolismo , Arteria Pulmonar/fisiopatología , Receptores Adrenérgicos beta 2/metabolismo , Vasoconstricción , Antagonistas de Receptores Adrenérgicos beta 2/administración & dosificación , Antagonistas de Receptores Adrenérgicos beta 2/farmacología , Animales , Presión Sanguínea , Fosfatidilinositol 3-Quinasa Clase Ia/metabolismo , Modelos Animales de Enfermedad , Progresión de la Enfermedad , Hipertensión Pulmonar/patología , Hipertrofia Ventricular Derecha , Masculino , Nadolol/farmacología , Óxido Nítrico Sintasa de Tipo III/metabolismo , Fosforilación , Proteínas Proto-Oncogénicas c-akt/metabolismo , Arteria Pulmonar/efectos de los fármacos , Ratas , Receptores Adrenérgicos beta 1/metabolismo , Factores de Tiempo , Vasoconstricción/efectos de los fármacos
11.
Curr Hypertens Rep ; 16(8): 452, 2014 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-25011397

RESUMEN

Oxidative stress plays a pivotal role in various pathological conditions, including hypertension, pulmonary hypertension, diabetes, and chronic kidney disease, with high levels of oxidative stress in target organs such as the heart, pancreas, kidney, and lung. Oxidative stress is known to activate multiple intracellular signaling, which induces apoptosis or cell overgrowth, leading to organ dysfunction. As such, targeting oxidative stress is thought to be effective in protecting against organ damage, and measuring oxidative stress status may serve as a biomarker in diverse disease states. Several new intrinsic anti-oxidative or pro-oxidative factors have recently been reported, and are potential new targets. In the present review, we focus on diabetes, pulmonary hypertension, and renal dysfunction, and their relation with new targets - adrenomedullin, oxidized LDL, and mineralocorticoid receptor.


Asunto(s)
Diabetes Mellitus/metabolismo , Hipertensión/metabolismo , Estrés Oxidativo/fisiología , Insuficiencia Renal Crónica/metabolismo , Animales , Apoptosis/fisiología , Humanos , Especies Reactivas de Oxígeno/metabolismo
12.
Am J Physiol Heart Circ Physiol ; 305(2): H155-62, 2013 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-23686713

RESUMEN

Chronic hypoxia is one of the main causes of pulmonary hypertension (PH) associated with ROS production. Lectin-like oxidized low-density lipoprotein receptor (LOX)-1 is known to be an endothelial receptor of oxidized low-density lipoprotein, which is assumed to play a role in the initiation of ROS generation. We investigated the role of LOX-1 and ROS generation in PH and vascular remodeling in LOX-1 transgenic (TG) mice. We maintained 8- to 10-wk-old male LOX-1 TG mice and wild-type (WT) mice in normoxia (room air) or hypoxia (10% O2 chambers) for 3 wk. Right ventricular (RV) systolic pressure (RVSP) was comparable between the two groups under normoxic conditions; however, chronic hypoxia significantly increased RVSP and RV hypertrophy in LOX-1 TG mice compared with WT mice. Medial wall thickness of the pulmonary arteries was significantly greater in LOX-1 TG mice than in WT mice. Furthermore, hypoxia enhanced ROS production and nitrotyrosine expression in LOX-1 TG mice, supporting the observed pathological changes. Administration of the NADPH oxidase inhibitor apocynin caused a significant reduction in PH and vascular remodeling in LOX-1 TG mice. Our results suggest that LOX-1-ROS generation induces the development and progression of PH.


Asunto(s)
Hipertensión Pulmonar/etiología , Hipoxia/complicaciones , Lipoproteínas LDL/metabolismo , Estrés Oxidativo , Arteria Pulmonar/metabolismo , Receptores Depuradores de Clase E/metabolismo , Animales , Antioxidantes/farmacología , Enfermedad Crónica , Modelos Animales de Enfermedad , Progresión de la Enfermedad , Inhibidores Enzimáticos/farmacología , Hipertensión Pulmonar/genética , Hipertensión Pulmonar/metabolismo , Hipertensión Pulmonar/patología , Hipertensión Pulmonar/fisiopatología , Hipertensión Pulmonar/prevención & control , Hipertrofia Ventricular Derecha/etiología , Hipertrofia Ventricular Derecha/genética , Hipertrofia Ventricular Derecha/metabolismo , Hipoxia/genética , Hipoxia/metabolismo , Hipoxia/fisiopatología , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , NADPH Oxidasas/antagonistas & inhibidores , NADPH Oxidasas/metabolismo , Estrés Oxidativo/efectos de los fármacos , Arteria Pulmonar/efectos de los fármacos , Arteria Pulmonar/patología , Arteria Pulmonar/fisiopatología , Especies Reactivas de Oxígeno/metabolismo , Receptores Depuradores de Clase E/genética , Transducción de Señal , Tirosina/análogos & derivados , Tirosina/metabolismo , Regulación hacia Arriba , Función Ventricular Derecha , Presión Ventricular
13.
Biochim Biophys Acta ; 1832(8): 1159-66, 2013 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-23499993

RESUMEN

Sleep apnea syndrome (SAS) is considered to be associated with heart failure (HF). It is known that autophagy is induced in various heart diseases thereby promotes survival, but its excess may be maladaptive. Intermittent hypoxia (IH) plays pivotal role in the pathogenesis of SAS. We aimed to clarify the relationships among IH, autophagy, and HF. Rats underwent IH at a rate of 20cycles/h (nadir of 4% O2 to peak of 21% O2 with 0% CO2) or normal air breathing (control) for 8h/d for 3weeks. IH increased the cardiac LC3II/LC3I ratio. The IH induced upregulation of LC3II was attenuated by the administration of an inhibitor of autophagosome formation 3-methyladenine (3-MA), but enhanced by an inhibitor of autophagosome-lysosome fusion chloroquine (CQ), showing enhanced autophagic flux in IH hearts. Electron microscopy confirmed an increase in autophagosomes and lysosomes in IH. With 3-MA or CQ, IH induced progressive deterioration of fractional shortening (FS) on echocardiography over 3weeks, although IH, 3-MA, or CQ alone had no effects. With CQ, IH for 4weeks increased serum troponin T levels, reflecting necrosis. Western blotting analyses showed dephosphorylation of Akt and mammalian target of rapamycin (mTOR) at Akt (Ser2448, 2481) sites, suggesting the activation of autophagy via Akt inactivation. Conclusions. IH-mediated autophagy maintains contractile function, whereas when autophagy is inhibited, IH induces systolic dysfunction due to myocyte necrosis. General significance. This study highlighted the potential implications of autophagy in cardio-protection in early SAS patients without comorbidity, reproduced in normal rats by 3~4weeks of IH.


Asunto(s)
Autofagia/fisiología , Cardiopatías/metabolismo , Hipoxia/fisiopatología , Contracción Muscular/fisiología , Miocardio/patología , Adenina/análogos & derivados , Adenina/farmacología , Animales , Autofagia/efectos de los fármacos , Cloroquina/farmacología , Cardiopatías/patología , Cardiopatías/fisiopatología , Insuficiencia Cardíaca/sangre , Insuficiencia Cardíaca/metabolismo , Insuficiencia Cardíaca/fisiopatología , Hipoxia/metabolismo , Lisosomas/efectos de los fármacos , Lisosomas/metabolismo , Lisosomas/fisiología , Masculino , Contracción Muscular/efectos de los fármacos , Miocardio/metabolismo , Miocitos Cardíacos/efectos de los fármacos , Miocitos Cardíacos/metabolismo , Miocitos Cardíacos/fisiología , Necrosis/sangre , Necrosis/metabolismo , Necrosis/fisiopatología , Fagosomas/efectos de los fármacos , Fagosomas/metabolismo , Fagosomas/fisiología , Proteínas Proto-Oncogénicas c-akt/metabolismo , Ratas , Ratas Sprague-Dawley , Serina-Treonina Quinasas TOR/metabolismo , Troponina T/sangre
14.
Cell Mol Life Sci ; 70(16): 2859-72, 2013 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-23124189

RESUMEN

Lectin-like oxidized LDL (oxLDL) receptor-1 (LOX-1, also known as OLR-1), is a class E scavenger receptor that mediates the uptake of oxLDL by vascular cells. LOX-1 is involved in endothelial dysfunction, monocyte adhesion, the proliferation, migration, and apoptosis of smooth muscle cells, foam cell formation, platelet activation, as well as plaque instability; all of these events are critical in the pathogenesis of atherosclerosis. These LOX-1-dependent biological processes contribute to plaque instability and the ultimate clinical sequelae of plaque rupture and life-threatening tissue ischemia. Administration of anti-LOX-1 antibodies inhibits atherosclerosis by decreasing these cellular events. Over the past decade, multiple drugs including naturally occurring antioxidants, statins, antiinflammatory agents, antihypertensive and antihyperglycemic drugs have been demonstrated to inhibit vascular LOX-1 expression and activity. Therefore, LOX-1 represents an attractive therapeutic target for the treatment of human atherosclerotic diseases. This review aims to integrate the current understanding of LOX-1 signaling, regulation of LOX-1 by vasculoprotective drugs, and the importance of LOX-1 in the pathogenesis of atherosclerosis.


Asunto(s)
Aterosclerosis/metabolismo , Receptores Depuradores de Clase E/antagonistas & inhibidores , Receptores Depuradores de Clase E/metabolismo , Animales , Aterosclerosis/tratamiento farmacológico , Humanos , Lipoproteínas LDL/metabolismo
15.
Transl Res ; 160(2): 114-24, 2012 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-22677363

RESUMEN

Lectin-like oxidized LDL (oxLDL) receptor-1 (LOX-1), a novel scavenger receptor highly expressed in human and experimental atherosclerotic lesions, is responsible for the uptake of oxLDL in vascular cells. We demonstrated previously that Tanshinone II-A (Tan), a pharmacologically active compound extracted from the rhizome of the Chinese herb Salvia miltiorrhiza Bunge, inhibits atherogenesis in hypercholesterolemic rats, rabbits, and apolipoprotein-E deficient (ApoE⁻/⁻) mice. However, the precise mechanism by which Tan protects against atherogenesis remains to be elucidated. Therefore, we hypothesized that Tan can suppress the uptake of oxLDL by diminishing the expression of LOX-1 via suppression of NF-κB signaling pathway, thereby contributing to reduced macrophage foam cell formation. In cultured murine macrophages, oxLDL induced LOX-1 expression at the mRNA and protein levels, was abrogated by addition of Tan or pyrrolidinedithiocarbamic acid ammonium salt (PDTC), a widely used inhibitor of NF-κB, suggesting the involvement of NF-κB. Tan also reduced LOX-1 expression in atherosclerotic lesions of ApoE⁻/⁻ mice fed a high cholesterol diet. Mechanistically, Tan suppressed the nuclear translocation of NF-κB P65 subunit and phosphorylation of IκB-α induced by oxLDL. Electrophoretic mobility shift assay (EMSA) demonstrated that Tan inhibited the nuclear protein binding to NF-κB consensus sequence. Functionally, we observed that Tan inhibited DiI-oxLDL uptake by macrophages in a fashion similar to that produced by LOX-1 neutralizing antibody. Our current findings reveal a novel mechanism by which Tan protects against atherogenesis and shed new light on the potential therapeutic application of Tan to the treatment and prevention of atherosclerotic cardiovascular diseases.


Asunto(s)
Abietanos/farmacología , Células Espumosas/efectos de los fármacos , Lipoproteínas LDL/farmacocinética , Macrófagos Peritoneales/efectos de los fármacos , FN-kappa B/metabolismo , Receptores Depuradores de Clase E/metabolismo , Animales , Antineoplásicos Fitogénicos/farmacología , Apolipoproteínas E/genética , Aterosclerosis/metabolismo , Aterosclerosis/prevención & control , Línea Celular , Medicamentos Herbarios Chinos/farmacología , Células Espumosas/citología , Células Espumosas/metabolismo , Expresión Génica/efectos de los fármacos , Expresión Génica/fisiología , Lipoproteínas LDL/metabolismo , Macrófagos Peritoneales/citología , Macrófagos Peritoneales/metabolismo , Ratones , Ratones Mutantes , Especies Reactivas de Oxígeno/metabolismo , Receptores Depuradores de Clase E/genética , Superóxidos/metabolismo , Investigación Biomédica Traslacional/métodos
16.
Am J Physiol Endocrinol Metab ; 302(4): E425-32, 2012 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-22114025

RESUMEN

Mineralocorticoid receptors (MRs) in the central nervous system play important roles in spatial memory, fear memory, salt sensitivity, and hypertension. Corticosterone binds to MRs to induce presynaptic vesicle release and postsynaptic α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor aggregation, which are necessary for induction of long-term potentiation under psychological stress. On the other hand, cognitive dysfunction is an important problem clinically in patients with hypertension, diabetes, and cerebral infarction, and all of these conditions are associated with an increase in reactive oxygen species (ROS) generation. Oxidative stress has been shown to modify the genomic actions of MRs in the peripheral organs; however, there have been no reports until now about the relation between the nongenomic actions of MRs and ROS in the central nervous system. In this study, we investigated the relationship between ROS and the nongenomic actions of MR. We examined the nongenomic actions of MR by measuring the slope of the field excitatory postsynaptic potentials and found that ROS induced an additive increase of these potentials, which was accompanied by Rac1 GTP activation and ERK1/2 phosphorylation. An NADPH oxidase inhibitor, apocynin, blocked the nongenomic actions of MRs. A Rac1 inhibitor, NSC23766, was also found to block synaptic enhancement and ERK1/2 phosphorylation induced by NADPH and corticosterone. We concluded that NADPH oxidase activity and Rac1 GTP activity are indispensable for the nongenomic actions of MRs and that Rac1 GTP activation induces ERK1/2 phosphorylation in the brain.


Asunto(s)
Región CA1 Hipocampal/metabolismo , NADPH Oxidasas/metabolismo , Receptores de Mineralocorticoides/metabolismo , Proteína de Unión al GTP rac1/metabolismo , Acetofenonas/farmacología , Aminoquinolinas/farmacología , Animales , Región CA1 Hipocampal/efectos de los fármacos , Región CA1 Hipocampal/fisiología , Corticosterona/farmacología , Inhibidores Enzimáticos/farmacología , Potenciales Postsinápticos Excitadores/efectos de los fármacos , Potenciales Postsinápticos Excitadores/fisiología , Sistema de Señalización de MAP Quinasas/efectos de los fármacos , Sistema de Señalización de MAP Quinasas/fisiología , Masculino , NADPH Oxidasas/antagonistas & inhibidores , NADPH Oxidasas/fisiología , Pirimidinas/farmacología , Ratas , Ratas Sprague-Dawley , Especies Reactivas de Oxígeno/metabolismo , Receptores de Mineralocorticoides/fisiología , Proteína de Unión al GTP rac1/antagonistas & inhibidores , Proteína de Unión al GTP rac1/fisiología
17.
Nat Med ; 17(5): 573-80, 2011 May.
Artículo en Inglés | MEDLINE | ID: mdl-21499270

RESUMEN

How high salt intake increases blood pressure is a key question in the study of hypertension. Salt intake induces increased renal sympathetic activity resulting in sodium retention. However, the mechanisms underlying the sympathetic control of renal sodium excretion remain unclear. In this study, we found that ß(2)-adrenergic receptor (ß(2)AR) stimulation led to decreased transcription of the gene encoding WNK4, a regulator of sodium reabsorption. ß(2)AR stimulation resulted in cyclic AMP-dependent inhibition of histone deacetylase-8 (HDAC8) activity and increased histone acetylation, leading to binding of the glucocorticoid receptor to a negative glucocorticoid-responsive element in the promoter region. In rat models of salt-sensitive hypertension and sympathetic overactivity, salt loading suppressed renal WNK4 expression, activated the Na(+)-Cl(-) cotransporter and induced salt-dependent hypertension. These findings implicate the epigenetic modulation of WNK4 transcription in the development of salt-sensitive hypertension. The renal ß(2)AR-WNK4 pathway may be a therapeutic target for salt-sensitive hypertension.


Asunto(s)
Hipertensión/genética , Hipertensión/metabolismo , Riñón/metabolismo , Proteínas Serina-Treonina Quinasas/metabolismo , Receptores Adrenérgicos beta 2/metabolismo , Animales , Secuencia de Bases , Conservación de la Sangre , Cartilla de ADN/genética , Epigénesis Genética , Histonas/metabolismo , Hipertensión/etiología , Hipertensión/fisiopatología , Riñón/efectos de los fármacos , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Modelos Biológicos , Proteínas Serina-Treonina Quinasas/antagonistas & inhibidores , Proteínas Serina-Treonina Quinasas/genética , ARN Interferente Pequeño/genética , Ratas , Ratas Endogámicas Dahl , Ratas Sprague-Dawley , Receptores de Glucocorticoides/antagonistas & inhibidores , Receptores de Glucocorticoides/deficiencia , Receptores de Glucocorticoides/genética , Receptores de Glucocorticoides/metabolismo , Transducción de Señal , Simportadores del Cloruro de Sodio/metabolismo , Cloruro de Sodio Dietético/administración & dosificación , Cloruro de Sodio Dietético/efectos adversos
18.
Clin Chem ; 56(4): 550-8, 2010 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-20093560

RESUMEN

BACKGROUND: Lectin-like oxidized LDL receptor 1 (LOX-1) is implicated in atherothrombotic diseases. Activation of LOX-1 in humans can be evaluated by use of the LOX index, obtained by multiplying the circulating concentration of LOX-1 ligands containing apolipoprotein B (LAB) times that of the soluble form of LOX-1 (sLOX-1) [LOX index = LAB x sLOX-1]. This study aimed to establish the prognostic value of the LOX index for coronary heart disease (CHD) and stroke in a community-based cohort. METHODS: An 11-year cohort study of 2437 residents age 30-79 years was performed in an urban area located in Japan. Of these, we included in the analysis 1094 men and 1201 women without history of stroke and CHD. We measured LAB and sLOX-1 using ELISAs with recombinant LOX-1 and monoclonal anti-apolipoprotein B antibody and with 2 monoclonal antibodies against LOX-1, respectively. RESULTS: During the follow-up period, there were 68 incident cases of CHD and 91 cases of stroke (with 60 ischemic strokes). Compared with the bottom quartile, the hazard ratio (HR) of the top quartile of LOX index was 1.74 (95% CI 0.92-3.30) for stroke and 2.09 (1.00-4.35) for CHD after adjusting for sex, age, body mass index, drinking, smoking, hypertension, diabetes, non-HDL cholesterol, and use of lipid-lowering agents. Compared with the bottom quartile of LOX index, the fully adjusted HRs for ischemic stroke were consistently high from the second to the top quartile: 3.39 (95% CI 1.34-8.53), 3.15 (1.22-8.13) and 3.23 (1.24-8.37), respectively. CONCLUSIONS: Higher LOX index values were associated with an increased risk of CHD. Low LOX index values may be protective against ischemic stroke.


Asunto(s)
Biomarcadores/sangre , Enfermedad Coronaria/sangre , Receptores Depuradores de Clase E/sangre , Accidente Cerebrovascular/sangre , Adulto , Anciano , Anticuerpos Monoclonales/inmunología , Reacciones Antígeno-Anticuerpo , Estudios de Cohortes , Femenino , Humanos , Masculino , Persona de Mediana Edad , Proteínas Recombinantes/sangre , Proteínas Recombinantes/inmunología , Factores de Riesgo , Receptores Depuradores de Clase E/inmunología
19.
Circ J ; 73(11): 1993-9, 2009 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-19801851

RESUMEN

Oxidatively modified low-density lipoprotein (oxLDL) is implicated in the pathogenesis of atherosclerosis. Endothelial dysfunction is the initial change in the vascular wall that induces morphological changes for atheroma-formation. Lectin-like oxidized LDL receptor-1 (LOX-1) was identified as the receptor for oxLDL that was thought to be a major cause of endothelial dysfunction. LOX-1 has been demonstrated to contribute not only to endothelial dysfunction, but also to atherosclerotic-plaque formation, myocardial infarction and intimal thickening after balloon injury. Recent findings on the genetics of LOX-1 and the methodology to detect it and its ligands would further facilitate the examination of the receptor's pathophysiological contribution in atherosclerosis. Furthermore, LOX-1-related tools might open new gateways from diagnosis to therapeutics for cardiovascular diseases.


Asunto(s)
Enfermedades Cardiovasculares/fisiopatología , Receptores Depuradores de Clase E/fisiología , Animales , Proteína C-Reactiva/fisiología , Enfermedades Cardiovasculares/etiología , Enfermedades Cardiovasculares/genética , Humanos , Riñón/lesiones , Riñón/fisiopatología , Ligandos , Modelos Cardiovasculares , Modelos Moleculares , Infarto del Miocardio/fisiopatología , Receptores Depuradores de Clase E/química , Receptores Depuradores de Clase E/genética , Transducción de Señal
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