Antioxidant effect of endothelin-1 receptor antagonist protects the rat kidney against chronic injury induced by hypertension and hyperglycemia / Efeito antioxidante de antagonista dos receptores de endotelina-1 protege ratos contra lesão renal crônica induzida por hipertensão e hiperglicemia

ABSTRACT Hypertension and Diabetes mellitus are the two main causes of chronic kidney disease that culminate in the final stage of kidney disease. Since these two risk factors are common and can overlap, new approaches to prevent or treat them are needed. Macitentan (MAC) is a new non-selective antagonist of the endothelin-1 (ET-1) receptor. This study aimed to evaluate the effect of chronic blockade of ET-1 receptor with MAC on the alteration of renal function observed in hypertensive and hyperglycemic animals. Genetically hypertensive rats were divided into control hypertensive (HT-CTL) group, hypertensive and hyperglycemic (HT+DIAB) group, and hypertensive and hyperglycemic group that received 25 mg/kg macitentan (HT-DIAB+MAC25) via gavage for 60 days. Kidney function and parameters associated with oxidative and nitrosative stress were evaluated. Immunohistochemistry for neutrophil gelatinase-associated lipocalin (NGAL), ET-1, and catalase in the renal cortex was performed. The HT+DIAB group showed a decrease in kidney function and an increase in NGAL expression in the renal cortex, as well as an increase in oxidative stress. MAC treatment was associated with attenuated ET-1 and NGAL production and increases in antioxidant defense (catalase expression) and nitric oxide production. In addition, MAC prevented an increase in oxidant injury (as measured by urinary hydroperoxide and lipid peroxidation), thus improving renal function. Our results suggest that the antioxidant effect of the ET-1 receptor antagonist MAC is involved in the improvement of kidney function observed in hypertensive and hyperglycemic rats.

RESUMO Hipertensão e Diabetes Mellitus figuram como as duas principais causas de doença renal crônica que culmina em doença renal terminal. Uma vez que os dois fatores de risco são comuns e podem se sobrepor, novas abordagens preventivas e terapêuticas se fazem necessárias. O macitentan (MAC) é um novo antagonista não-seletivo dos receptores da endotelina-1 (ET-1). O presente estudo teve como objetivo avaliar os efeitos do bloqueio crônico dos receptores da ET-1 com MAC sobre a alteração da função renal em animais hipertensos e hiperglicêmicos. Ratos geneticamente hipertensos foram divididos em grupos com animais hipertensos de controle (HT-CTL), hipertensos e hiperglicêmicos (HT+DIAB) e hipertensos e hiperglicêmicos tratados com 25 mg/kg de macitentan (HT-DIAB+MAC25) via gavagem por 60 dias. Foram avaliados função renal e parâmetros associados ao estresse oxidativo e nitrosativo. Exames de imunoistoquímica foram realizados para lipocalina associada à gelatinase neutrofílica (NGAL), ET-1 e catalase no córtex renal. O grupo HT+DIAB exibiu diminuição da função renal e aumento na expressão de NGAL no córtex renal, bem como estresse oxidativo aumentado. O tratamento com MAC foi associado a atenuação da produção de ET-1 e NGAL e maior ativação das defesas antioxidantes (expressão de catalase) e elevação da produção de óxido nítrico. Além disso, o MAC evitou exacerbação da lesão oxidante (medida por hidroperóxidos urinários e peroxidação lipídica), melhorando assim a função renal. Nossos resultados sugerem que o efeito antioxidante do antagonista dos receptores da ET-1 MAC esteja imbricado no aprimoramento da função renal observada em ratos hipertensos e hiperglicêmicos.

Protective effects of melatonin on spinal cord injury / Efectos protectores de la melatonina en lesión de la médula espinal

Spinal cord injury causes neuron nerve fiber loss. The aim of this study was to investigate the neuroprotective, inflammatory and angiogenetic effects of melatonin on rat spinal cord injury (SCI). For spinal cord injury, a standard weight reduction method was used that caused moderate severity of injury (100 g / cm force) at T10 Melatonin (10 mg/kg intraperitoneally ) was administered for 10 days after trauma. Each group consisted of 10 animals. of these, six were used for biochemical and four were used for the evaluation of histological analysis. Spinal cord samples were taken for histological examination or determination of malondialdehyde (MDA) and glutathione (GSH) levels, myeloperoxidase (MPO) activity. Spinal cord injury and melatonin treated group were compared. Melatonin administration in spinal cord injury increased the activity of glial cells in the radial and funicular cells and ependymal cells and increased the activity of glial cells and also showed a positive effect on inflammation and vascular endothelial cells in synaptic connections in the nerve fibers undergoing spinal injury endothelial degeneration It is thought that it can regulate the degenerative effect which is caused by both the inflammatory effect and the angiogenic effect which will have a positive effect on the neural connection.

La lesión de la médula espinal (SCI) provoca daño en la fibra nerviosa, que puede conducir a alteraciones motoras y sensitivas, incluso la muerte. El objetivo de este estudio fue investigar los efectos neuroprotectores, proinflamatorios y proangiogénicos de la melatonina en un modelo de SCI inducida en rata. Para tal efecto se utilizaron dos grupos: Grupo 1 (n:10) se le indujo una SCI, mediante el método de reducción de peso estándar (100 g/cm fuerza), provocando una lesión de severidad moderada. Grupo 2 (n:10) inducción SCI más aplicación de T10 Melatonina (10 mg / kg v.i.) durante 10 días después del trauma. Muestras de seis animales de cada grupo fueron usados para análisis bioquímicos y los otros cuatro para la evaluación histológica. Se tomaron muestras de médula espinal para el examen histológico y para la determinación de niveles de malondialdehído (MDA) y glutatión (GSH), actividad mieloperoxidasa (MPO) y se comparó la lesión de la médula espinal y el grupo tratado con melatonina. La administración de melatonina en la lesión de la médula espinal aumentó la actividad de las células gliales en las células radiales, funiculares y ependimocitos. Ademas mostró un efecto positivo sobre la inflamación y angiogénesis en las conexiones sinápticas en las fibras nerviosas sometidas a lesión espinal. Pudiendo este participar en la regulación del efecto degenerativo causado, principalmente, por acción de angiogénesis e inflamación local.

Expression of endothelin-1 and Ki-67 in normotensive and severe preeclamptic placentas / Expresión de endotelina-1 y Ki-67 en placentas normotensas y preeclampsia severa

SUMMARY: Severe preeclampsia (HELLP syndrome) is a life-threatening pregnancy complication, usually a severe form of preeclampsia. In this study, we aimed to examine histopathologic changes and Endothelin-1 and KI-67 expression levels by immunohistochemical methods in severe preeclamptic placentas. Severe preeclampsia and obstetric characteristics and biochemical and hematological characteristics of healthy subjects were compared. Placenta sections were stained with hematoxylin-eosin for histopathological examination. In the histopathological examination of severe preeclamptic placenta, degeneration in synaptic and cytotrophoblastic cells, increase in insidious knots, fibrinoid necrosis, degeneration in endothelial cells, calcification and hyaline villous stains were observed. In the severe preeclampsia group, Ki-67 expression increased in decidua cells and inflammatory cells, while endothelial cells in the vessel wall and inflammatory cells in the villus and intervillous spaces increased. It is thought that angiogenetic and cellular proliferation is induced in a co-ordinated manner and significantly influences fetal development.

RESUMEN: La preeclampsia severa (síndrome de HELLP) es una complicación del embarazo potencialmente mortal, generalmente una forma grave de preeclampsia. En este estudio, nuestro objetivo fue examinar los cambios histopatológicos y los niveles de expresión de Endotelina-1 y Ki-67 mediante métodos inmunohistoquímicos en placentas preeclámpsicas graves. Se compararon la preeclampsia grave y las características obstétricas, además de las características bioquímicas y hematológicas de pacientes sanas. Las secciones de placenta se tiñeron con hematoxilina-eosina para examen histopatológico. En el examen histopatológico de placenta preeclampsia severa, se observó la degeneración en células sinápticas y citotrofoblásticas, un aumento de nudos insidiosos, necrosis fibrinoide, degeneración en las células endoteliales,calcificación y manchas vellosas hialinas. En el grupo de preeclampsia grave, la expresión de Ki-67 aumentó en células deciduas y células inflamatorias, mientras que las células endoteliales en la pared del vaso, y las células inflamatorias en las vellosidades y los espacios intervellosos aumentaron. Se cree que la proliferación angiogenética y celular se induce de forma coordinada y que influye significativamente en el desarrollo fetal.

The Effect of Umbilical Cord Blood Derived Mesenchymal Stem Cells in Monocrotaline-induced Pulmonary Artery Hypertension Rats

Pulmonary arterial hypertension (PAH) causes right ventricular failure due to a gradual increase in pulmonary vascular resistance. The purposes of this study were to confirm the engraftment of human umbilical cord blood-mesenchymal stem cells (hUCB-MSCs) placed in the correct place in the lung and research on changes of hemodynamics, pulmonary pathology, immunomodulation and several gene expressions in monocrotaline (MCT)-induced PAH rat models after hUCB-MSCs transfusion. The rats were grouped as follows: the control (C) group; the M group (MCT 60 mg/kg); the U group (hUCB-MSCs transfusion). They received transfusions via the external jugular vein a week after MCT injection. The mean right ventricular pressure (RVP) was significantly reduced in the U group after the 2 week. The indicators of RV hypertrophy were significantly reduced in the U group at week 4. Reduced medial wall thickness in the pulmonary arteriole was noted in the U group at week 4. Reduced number of intra-acinar muscular pulmonary arteries was observed in the U group after 2 week. Protein expressions such as endothelin (ET)-1, endothelin receptor A (ERA), endothelial nitric oxide synthase (eNOS) and matrix metalloproteinase (MMP)-2 significantly decreased at week 4. The decreased levels of ERA, eNOS and MMP-2 immunoreactivity were noted by immnohistochemical staining. After hUCB-MSCs were administered, there were the improvement of RVH and mean RVP. Reductions in several protein expressions and immunomodulation were also detected. It is suggested that hUCB-MSCs may be a promising therapeutic option for PAH.

Increased cardiac endothelin-1 and nitric oxide in adriamycin-induced acute cardiotoxicity: Protective effect of Ginkgo biloba extract.

Cardiotoxicity and congestive heart failure are the major factors that limit the use of anti-neoplastic drug adriamycin (ADR). There is increasing experimental evidence that endothelin-1 (ET-1) and nitric oxide (NO) are vasoactive mediators that regulate cardiac performance. The present study was undertaken to investigate the role of ET-1 and NO in ADR-induced acute cardiotoxicity and to evaluate the protective effect of Ginkgo biloba extract (EGb761) in rats. A single dose of ADR (20 mg/kg i.p.) caused a significant increase in the cardiac enzyme activities of aspartate transaminases (AST), lactate dehydrogenase (LDH) and creatine phosphokinase isoenzyme (CK-MB) in the serum of animals. This was accompanied by significant increase in cardiac malondialdehyde (MDA), total antioxidant capacity (TAC), tumor necrosis factor-alpha (TNF-α), ET-1 and nitrite/nitrate (NOx) levels. On the other hand, reduced glutathione (GSH) was significantly depressed. Histopathological examination of heart tissues showed hyalinization of the myocardium, with interstitial edema and inflammatory exudates. Pre-treatment of the animals with EGb761 (100 mg/kg, orally) 10 days before and 5 days after ADR treatment reversed the cardiac enzyme levels to normal value, decreased cardiac MDA, TAC, TNF-α, ET-1 and NOx, increased GSH and reversed the histopathological damage induced by ADR. In conclusion, the cardioprotective effects of EGb761 on markers of ADR-induced acute cardiotoxicity appeared to have been mediated by the regulation of inflammatory and vasoactive mediators, as well as the inhibition of membrane lipid peroxidation. Thus, EGb761 may find use as promising adjuvant therapy to ameliorate cardiotoxicity of ADR.

Beneficial effect of Lisosan G on cultured human microvascular endothelial cells exposed to oxidised low density lipoprotein.

Background & objectives: Nutritional compounds which display anti-inflammatory and antioxidant effects have specific applications in preventing oxidative stress and endothelial dysfunction. In this study we evaluated the effect of Lisosan G (powder of Triticum sativum grains) on human microvascular endothelial cells (HMEC-1) exposed to oxidized low density lipoprotein (ox-LDL). Methods: The protective effects of Lisosan G were evaluated on human microvascular endothelial cells exposed to ox-LDL. Intercellular adhesion molecular-1 (ICAM-1), endothelin-1 (ET-1), and interleukin-6 (IL-6) concentrations and the expression of the respective genes were evaluated in response to incubation with ox-LDL, after co-incubation with ox-LDL and Lisosan G or exposed to Lisosan G alone. The analysis of LOX-1 gene was performed with RT-PCR semi quantitative method. The degree of oxidation induced in relation to control, was established by measurement of malondialdehyde (MDA) production. Results: The incubation with ox-LDL induced a significant increase in ICAM-1, IL-6 and ET-1 levels compared to the basal condition (P<0.01, P<0.05, and P<0.01, respectively), while in presence of Lisosan G, ICAM-1 levels showed a significant reduction both compared to the cultures treated with ox-LDL and control (P<0.01). IL-6 levels did not show any difference; ET-1 levels showed a partial reduction after co-treatment with Lisosan G, and also with Lisosan G alone, reduced the concentration below control (P<0.01). The modulation of these markers was confirmed by RT-PCR analysis. An association between MDA formation and the three markers production was observed. Semi-quantitative analysis of LOX-1 gene expression showed a significant up-regulation only after ox-LDL exposure. Interpretation & conclusions: The results demonstrate that Lisosan G may have an important role in the prevention of microcirculatory dysfunction.

Absence of arteriosclerosis in intramyocardial coronary arteries: a mystery to be solved? / Ausência de arteriosclerose na porção intramiocárdica das artérias coronárias: um mistério a ser resolvido?

Several studies show that portions of intramyocardial coronary arteries are spared of arteriosclerosis, involving morphological, embryological, biochemical and pathophysiological aspects. Endothelial function is significantly affected in the segment of transition, as estimated by the vasoactive response to Ach. These findings suggest that myocardial bridge can provide protection against arteriosclerosis by counteracting the negative effects of endothelial dysfunction. The intramyocardial portion's protection phenomenon deserves further scientific research on all research fronts. Improved morphological, biomechanical and especially physiological and embryological knowledge may be the key to a future window of opportunity for chronic arterial disease therapy and prevention. In addition, this review discusses possible therapeutic approaches for symptomatic coronary ischemia caused by myocardial bridges.

Diversos estudos demonstram que as porções intramiocárdicas das artérias coronárias são poupadas da arteriosclerose, envolvendo aspectos morfológicos, embriológicos, biomecânicos e aspectos fisiopatológicos. A função endotelial é significativamente afetada no segmento de transição, tal como estimado pela resposta vasoativa para acetilcolina (Ach). Esses achados sugerem que ponte miocárdica pode fornecer proteção contra a arteriosclerose, por contrariar os efeitos negativos da disfunção endotelial. O fenômeno dessa proteção da porção intramiocárdica merece maior investigação científica em todas as frentes de pesquisa. Maiores conhecimentos sobre os aspectos morfológicos, biomecânicos e, principalmente, fisiológicos e embriológicos podem ser a chave para uma futura janela de oportunidades de terapia e prevenção da doença arterial crônica. Nessa revisão, discutem-se, também, possíveis abordagens terapêuticas para fenômenos coronarianos isquêmicos causados por pontes miocárdicas.

The Role of Endothelin Receptor A during Myelination of Developing Oligodendrocytes

Endothelin (ET)-1 and its receptors (ETA and ETB receptor) are present in the central nervous system. ET exerts biological effects on gliogenesis and glial cell functions. In order to define a possible mechanism of ETA receptor signaling, the distribution of the ETA receptor in developing oligodendrocytes and the effects of ET-1 on the myelination of oligodendrocytes were examined. ETA receptor immunoreactivity was confined to the perivascular elements of the blood vessels during early postnatal development. However later in development, ETA receptor immunoreactivity was no longer observed in the vessels but became localized to the myelinating oligodendrocytes of the primitive corpus callosum of the white matter, apart from the vessels. ET-1 induced myelin basic protein (MBP) in primary oligodendrocyte precursor cell culture though the ETA receptor and was blocked by an ETA receptor antagonist. In addition, ET-1 evoked the release of Ca2+ which is a central regulator of oligodendrocyte differentiation. Our results provide a link between ET-1 and its ETA receptor and myelination during oligodendrocyte differentiation.

Endothelin-1 and leptin as markers of intrauterine growth restriction.

Objective. To explore the role of endothelin-1 (ET-1) and leptin in intrauterine growth restriction (IUGR) among preeclamptic and non-pre-eclamptic women. Methods. Forty three patients with a pregnancy complicated by IUGR, 23 cases with severe pre-eclampsia and 20 cases of non-pre-eclamptic were enrolled. Control group comprised 15 cases with uncomplicated pregnancy. Blood samples from umbilical artery and maternal venous blood were collected at the time of delivery for analysis of ET-1 and leptin levels. Mode of delivery, birth weight and Apgar score were also recorded. Results. The mean maternal and fetal ET-1 level was significantly higher in pregnancies complicated by IUGR than in control group. The mean maternal leptin level was significantly higher in pre-eclamptic patients when compared to nonpreeclamptic and control groups. Mean fetal leptin level was significantly lower in patients compared to control; however, when fetal leptin corrected to fetal weight, it was insignificantly different in the both groups. Conclusion. Maternal plasma ET-1 and leptin correlate with the degree of fetal growth restriction originating from deterioration of placental function. Maternal plasma leptin and ET-1 levels may reflect deterioration in fetal growth.

Liberacion de endotelina-1 por angiotensina ii en miocitos cardiacos aislados / Angiotensin II-induced endothelin-1 release in cardiac myocytes

Muchos de los efectos de la angiotensina II (Ang II) son mediados en realidad por la acción de endotelina (ET) endógena liberada y/o producida en respuesta a la Ang II. En este trabajo evaluamos la interacción Ang II/ET-1, sus consecuencias en la contractilidad cardíaca y el papel de las especies reactivas del oxígeno (EROs). Se usaron cardiomiocitos aislados de gato. La Ang II, 1 nM, produjo un efecto inotrópico positivo (EIP) de 31.8±3.8% que fue cancelado por inhibición de los receptores AT1, de los receptores de ET, del intercambiador Na+/H+ (NHE), del modo inverso del intercambiador Na+/Ca2+ (NCX) o por el secuestro de EROs. La Ang II, 100 nM, produjo un EIP de 70.5±7.6% que fue cancelado por inhibición de los receptores AT1y bloqueado en parte por inhibición de los receptores de ET, del NHE, del modo inverso del NCX o por el secuestro de EROs. La Ang II, 1 nM, incrementó el ARNm de la preproET-1 lo cual fue anulado por el bloqueo de los receptores AT1. Los resultados permiten concluir que el EIP de la Ang II es debido a la acción de la ET-1 endógena liberada/formada por la Ang II. La ET-1 produce: estimulación del NHE, activación del modo inverso del NCX y un consecuente EIP. Dentro de esta cascada también participarían los EROs.

Many of the effects thought to be due to angiotensin II (Ang II) are due to the release/formation of endothelin (ET). We tested whether Ang II elicits its positive inotropic effect (PIE) by the action of endogenous ET-1 and the role played by the reactive oxygen species (ROS) in this mechanism. Experiments were performed in cat isolated ventricular myocytes in which sarcomere shortening (SS) was measured to asses contractility after pharmacological interventions and the effect of Ang II on inotropism were analyzed. Ang II 1 nM increased SS by 31.8±3.8% (p<0.05). This PIE was cancelled by AT1 receptor blockade, by ET-1 receptors blockade, by Na+/H+ exchanger (NHE) inhibition, by reverse mode Na+/Ca2+ exchanger (NCX) blockade or by ROS scavenging. Ang II 100 nM increases SS by 70.5±7.6% (p<0.05). This PIE was completely abolished by AT1 receptors blockade and were partially bocked by ET-1 receptors blockade, by NHE inhibition, by reverse mode NCX blockade or by ROS scavenging. Ang II increased preproET-1 mRNA, effect that was blunted by AT1 receptors blockade. We conclude that Ang II induces (through its AT1 receptor) release/formation of ET-1, which acting in autocrine fashion on ET receptors of the isolated myocytes increases inotropism through NHE stimulation and NCX reverse mode activation. The participation of ROS is involved is this chain of events.

Correlation between pulmonary endothelin receptors and alveolar-arterial oxygen gradient in rats with hepatopulmonary syndrome / 华中科技大学学报（医学）（英德文版）

The correlation between pulmonary endothelin receptors and alveolar-arterial oxygen gradient (A-aDO2) in rats with hepatopulmonary syndrome was investigated. Animals were divided into 2 groups: Sham-operated (Sham) group and common bile duct ligation (CBDL) group. Arterial blood gas was evaluated by a blood gas analyzer. The concentrations of ET-1 in blood and lung tissue sample were evaluated by radioimmunoassay. The distribution and expression of two kinds of subtype receptor of ET-1, ETRA and ETRB were examined by in situ hybridization. The results showed that the level of A-aDO2 was higher in CBDL group than that in Sham group (P 0.05), while that of ETRB was higher in CBDL group than in Sham group (0.58 +/- 0.16 vs 0.28 +/- 0.07, P < 0.05). The expression of ETRB in lung was positively correlated with A-aDO2 (P < 0.05). It was concluded that the widened A-aDO2 may be related with enhancement of the expression of ETRB in lung.

Individual or combined effects of enalapril and verapamil on chronic cyclosporine nephrotoxicity in rats

Previous studies have demonstrated that enalapril and verapamil seem to attenuate the cyclosporine nephrotoxicity. However, the mechanisms have not been completely understood, especially on molecular events. The aim of this study was to examine the effect of individual or combined treatment on osteopontin, TGF-beta, endothelin-1 and procollagen alpha 1(I) mRNA expressions. Enalapril (50 mg/L in drinking water) and verapamil (0.5 mg/kg/day, subcutaneously), alone or in combination, were administered to rats with chronic cyclosporine nephrotoxicity (cyclosporine, 25 mg/kg/day, subcutaneously) (n = 5 each). Five rats treated with olive oil vehicle were used as control. After 4 weeks, biochemical parameters were measured, and renal cortical mRNA levels were evaluated by Northern blot analysis. Cyclosporine reduced renal creatinine clearance significantly and induced renal cortical osteopontin, TGF-beta, endothelin-1 and procollagen alpha 1(I) gene expressions around 13.5 +/- 1.3, 2.4 +/- 0.2, 1.5 +/- 0.1, 1.9 +/- 0.1 folds, respectively. Individual treatment with enalapril or verapamil significantly suppressed the osteopontin and TGF-beta mRNA expression, but not endothelin-1 and procollagen alpha 1(I). Combined treatment also inhibited the osteopontin and TGF-beta mRNA expression but there was no difference between combined and individual treatment. In conclusion, enalapril or verapamil significantly blunted the cyclosporine-induced osteopontin and TGF-beta gene expressions. However, combined treatment did not show any additive effect.