Abstract:Endothelin-1 (ET-1) is a potent vasoconstrictor. It induces vascular contraction, stimulates proliferation of vascular smooth muscle cells and vascular remodeling in the pathogenesis of cardiovascular disease including pulmonary hypertension. Many studies have demonstrated that activation of mitogen-activated protein kinase (MAPK)/nuclear factor-kappaB (NF-κB) signal pathway induces up-regulation of endothelin receptors, and the up-regulation of endothelin receptors in pulmonary vascular smooth muscle cells results in pulmonary artery hypersensitivity and hyperresponsiveness to ET-1 with enhanced pulmonary vascular contraction, even spasm. This review article summarizes the roles of endothelin-1 and its receptors in the pathogenesis of pulmonary hypertension with focusing on the relationships between the up-regulation of endothelin receptors and pulmonary hypersensitivity and hyperresponsiveness, as well as down-regulation of endothelin receptors by inhibiting MAPK/NF-κB signal pathway. The inhibition of the endothelin receptor up-regulation in pulmonary artery improves pulmonary hypersensitivity and hyperresponsiveness to ET-1, and thus may provide a new strategy and novel therapeutic targets for the treatment of pulmonary hypertension.

Abstract:Aim To investigate the protective effect of olmesartan on vascular endothelial function in patients with hypertension complicated with coronary heart disease and diabetes mellitus, by observing the change of vascular endothelial function before and after treatment with olmesartan. Methods 160 cases of hypertensive patients were collected, and according to whether complicated with coronary heart disease and diabetes mellitus, the patients were divided into 3 groups:pure hypertension group (H group, n＝40), hypertension complicated with coronary heart disease group (HC group, n＝62) and hypertension complicated with coronary heart disease and diabetes mellitus group (HCD group, n＝58). And then each group was divided into 2 subgroups:olmesartan intervention subgroup (A subgroup) and and non olmesartan intervention subgroup (B subgroup). Baseline data and general examination indicators of each group were counted. Enzyme-linked immunosorbent assay was used to detect the concentration of serum nitric oxide (NO) and endothelin-1 (ET-1). The number of peripheral blood endothelial progenitor cell (EPC) was detected by flow cytometry.Above indicators were reexamined after intervention with olmesartan for 3 months. Results (1)Vascular endothelial relaxing and contracting factors:Before treatment, compared with H group, NO concentration was significantly lower, while ET-1 concentration was significantly increased in HC group and HCD group, and the change of HCD group was more obvious (P＜0.05). After treatment, compared with before treatment, NO concentration was significantly increased, while ET-1 concentration was decreased in HC-A subgroup and HCD-A subgroup (P＜0.05). (2) EPC number of peripheral blood:Before treatment, compared with H group, the EPC number of peripheral blood was significantly decreased in HC group and HCD group, and the decrease of HCD group was more obvious (P＜0.05). After treatment, compared with before treatment, the number of EPC was significantly increased in HC-A subgroup and HCD-A subgroup (P＜0.05). Conclusions Hypertensive patients complicated with coronary heart disease and diabetes mellitus will increase the damage of vascular endothelium. Olmesartan can inhibit the imbalance of vascular endothelial relaxing and contracting factors, increase the EPC number of peripheral blood, and it has protective effect to vascular endothelium.

Abstract:Aim To explore the effect of sitagliptin on the expression of endothelin-1(ET-1) and endothelial nitric oxide synthase(eNOS) in human aortic endothelial cells(HAEC) and its underlying mechanism in high glucose environment. Methods HAEC were cultured in high glucose environment(25 mmol/L), and treated with different concentrations of sitagliptin(0, 5, 10 and 20 μmol/L, respectively). The mRNA and protein expressions of eNOS, ET-1, iNOS and phosphate nuclear factor-kappa B p65(p-NF-κB p65) were measured. The measurements for eNOS, ET-1, iNOS, NF-κB p65 on mRNA and protein levels in HAEC were evaluated after incubation with tumor necrosis factor-α(TNF-α) and sitagliptin. Results Compared with normal medium(glucose concentrations for 7 mmol/L), both the mRNA and the protein expression of eNOS in HAEC significantly decreased in high glucose medium, while those of ET-1, iNOS and p-NF-κB p65 protein significantly increased(P<0.05). Compared with 0 μmol/L sitagliptin, 20 μmol/L sitagliptin significantly increased mRNA and protein expressions of eNOS, while decreased those of ET-1, iNOS and p-NF-κB p65 protein(P<0.05). Compared with sitagliptin alone treated HAEC, both the mRNA and the protein expressions of eNOS significantly decreased in HAEC treated with TNF-α and sitagliptin, while those of ET-1, iNOS and p-NF-κB p65 protein expressions significantly increased(P<0.05). Conclusions Sitagliptin enhances eNOS, represses ET-1, iNOS expressions at the level of transcription and translation through inhibiting NF-κB p65 phosphorylation in HAEC in high glucose environment. This may contribute to the improvement of endothelial function and prevention of subsequent atherogenesis.

Abstract:There are two local conditions for coronary artery spasmie. Firstly, coronary artery smooth muscle hyperresponsiveness that leads to coronary artery hypersensitive to vasoconstrictor substances results in increased contraction and even spasm and secondly, enough vasoconstrictor substances exists locally to induce coronary artery spasm. Endothelin-1 is the strongest vasoconstrictor substance in man. Studies have demonstrated that activation of extracellular signal-regulated kinases 1 and 2(ERK1/2)by risk factors for coronary spasm like hyperlipidemia and cigarette smoke can mediate endothelin receptor upregulation in coronary artery smooth muscle cells, subsequently results in significantly increased coronary artery sensitivity to endothelin-1 and leads to increase in vasoconstriction, and even vasospasm. Here, we review recent studies on the role of endothelin receptor upregulation in coronary artery spasm, which might provide new therapeutic targets and novel strategy for treatment of coronary artery spasm.

Abstract:Aim Certain long-chain water-soluble polymer,known as drag reducing polymer （DRP）,when added in minute concentrations,have been shown to decrease peripheral vascular resistance. In this study,the effect of DRP on the hypertension-induced aortic remodeling was evaluated in spontaneous hypertensive rat （SHR）.Methods 24 male SHR were divided into three groups 8 male,age matched Wistar rats （WR） as control. The experimental groups of SHR received an intravenous injection of normal saline （SHR＋NS group）,10 mg/L DRP （SHR＋10 mg/L DRP group）,20 mg/L DRP （SHR＋20 mg/L DRP group）,respectively. The control group only received equal-volume of normal saline （WR＋NS group）. The whole study spanned 2 months,and body weight,heart rate,systolic blood pressure were measured at the beginning and every 20 days. Then blood sample and aorta were collected. Serum endothelin （ET） was measured by enzyme-linked immunosorbent assay （ELISA）. The aorta was stained by hematoxylin-eosin （HE）,andaortic medial thickness was evaluated for each section. The expression of endothelin-1 （ET-1） of aorta was examined by immunohistochemistry.Results There was no significant difference between the SHR groups in body weight and heart rate during the treatment period. Systolic blood pressure was significantly reduced in SHR＋20 mg/L DRP group than in SHR＋NS group （P<0.05）,while there was no significant difference between SHR＋10 mg/L DRP group and SHR＋NS group. Compared with the SHR＋NS group,the levels of serum ET decreased in SHR＋10 mg/L DRP group and SHR＋20 mg/L DRP group （P<0.05）. The medial thickness of the aorta was reduced in SHR＋10 mg/L DRP group and SHR＋20 mg/L DRP group compared with SHR＋NS group. The expression of ET-1 of the aorta was significantly attenuated in SHR＋10 mg/L DRP group and SHR＋20 mg/L DRP group.Conclusions These results suggest that chronic treatment with DRP can protect against aortic remodeling in spontaneous hypertensive rats,possibly by improving blood shear stress in aorta. DRP may offer a new approach to the treatment of aortic remodeling caused by hypertension.

Abstract:Aim To examine whether L-type calcium channel （LCC） of human umbilical arterial smooth muscle cells （HUASMC） was influenced by endothelin-1（ET-1）, and whether the possible influence was interfered with by quercetin which has been shown to provide protection against cardiovascular diseases. Methods Primary HUASMC at the third passage culture were identified by immunocytochemistry and randomly divided into following groups:①control group: cultured only with vehicle for 24 h. ② Quercetin alone group: cultured with 80 μmol/L quercetin for 24 h. ③Model group: cultured with 10 nmol/L ET-1 for 24 h. ④U0126 plus ET-1 group: pretreated with 10 μmol/L U0126 for 1 h, then coincubated with 10 nmol/L ET-1 for 24 h. ⑤Quercetin pretreatment group: pretreated with quercetin in concentrations of 20 μmol/L, 40 μmol/L and 80 μmol/L respectively for 1 h, then coincubated with 10 nmol/L ET-1 for another 24 h. ⑥ET-1+Que+U0126 group: pretreated with 80 μmol/L quercetin and 10 μmol/L U0126 together for 1 h, then coincubated with 10 nmol/L ET-1 for 24 h. ⑦ET-1+nifedipine group: pretreated with 10 μmol/L nifedipine for 1 h, then coincubated with 10 nmol/L ET-1 for 24 h. Expression of α1C, a LCC major subunit , was assayed by RT-PCR and Western blot analysis. The LCC currents（ICaL） were detected by technique of whole-cell patch-clamp. Results α1C expression , in both mRNA and protein level, as well as ICaL density of model group were significantly down-regulated compared with that of control group or quercetin alone group（P<0.05）, and the repressing effect of ET-1 on LCC was partly reversed by pretreating with U0126 or quercetin（P<0.05）. No significant difference between control group and quercetin alone group was detected. Conclusion Downregulation of α1C expression and ICaL density in HUASMC by ET-1 partly via ERK parthway was antagonized by quercetin, which could be an important mechanism contributing to the protective effect of quercetin on cardiovascular system.

Abstract:Aim To explore the effect of autophagy intervention on endothelial cells endothelial nitric oxide synthase （eNOS） and endothelin-1 （ET-1） expression under low shear stress. Methods ApoE－/－ mice were fed with high fat diet for 12 weeks. HE staining was used to detect the pathological changes of aortic sinus. Immunohistochemistry was applied to detect the protein expression of autophagy markers Beclin1, microtubule-associated protein 1 light chain 3 （LC3Ⅱ） and p62. Human umbilical vein endothelial cells （HUVEC） and separated New Zealand rabbits common carotid arteries were placed into an in vivo perfusion system with low shear stress （5 dyne/cm2） or normal shear stress （15 dyne/cm2） for 1 h, then the expression of Beclin1, LC3Ⅱ/LC3Ⅰ and p62 was measured using Western blot. After treated with 5 dyne/cm2 for 1 h followed with or without rapamycin or 3-methyladenine （3-MA） for 30 min, the expression of eNOS and ET-1 in human vascular endothelial cells and common arteries of New Zealand rabbits was detected. Results The expression of Beclin1, LC3Ⅱ and p62 was significantly increased in atherosclerotic plaque. Compared with 15 dyne/cm2 treatment group, the expression of Beclin1, LC3Ⅱ and p62 was significantly increased in 5 dyne/cm2 treatment group （P<0.05）. The autophagy inducer rapamycin up-regulated the eNOS expression and inhibited the ET-1 expression in both 5 dyne/cm2 treated HUVEC and common carotid arteries, whereas autophagy inhibitor 3-MA further inhibited eNOS expression and increased the ET-1 expression. Conclusion The inhibition of autophagy might contribute to the decreased expression of eNOS and the increased expression of ET-1 under low shear stress, which was improved by promoting autophagy.

Abstract:AimTo study the effect and mechanism of rhynchophylla total alkaloids, sinapine cyanide sulfonate and its component compatibility on change of vascular endothelial cells induced by the tumor necrosis factor-α(TNF-α).MethodsRat vascular endothelial cells were cultured in vitro, and vascular endothelial cell injury model was established by TNF-α.Then changes of cell morphology were observed before and after treatment; intercellular adhesion molecule-1(ICAM-1), vascular cell adhesion molecule-1(VCAM-1) and rat endothelin-1 (ET-1) were determined by Elisa method, mRNA of ICAM-1, VCAM-1 and ET-1 by RT-PCR method and the level change of endothelium-derived relaxing factor (NO) by nitrate reductase method.ResultsThe vascular endothelial cell injury model could be established in vitro successfully by TNF-α (5 μg/L).Compared with TNF-α group, treated groups could improve vascular endothelial cell morphology, lower the secretion of ICAM-1,VCAM-1 and ET-1.Compared with rhynchophylla total alkaloids group and sinapine cyanide sulfonate group, the component compatibility group was better on heightening the secretion of NO, down-regulating the expression of ICAM-1 mRNA(P<0.05).On down-regulating the expression of mRNA of VCAM-1

Abstract:AimTo observe the effect of ibrolipim on the expresstion of endothelin-1 (ET-1) and von Willebrand factor (vWF) in cultured human umbilical vein endothelial cells induced by high glucose, and to investigate its molecular mechanism.MethodsHuman umbilical vein endothelial cell-12 (HUVEC-12) were cultured respectively under normal glucose level (5.5 mmol/L), high glucose level (33.3 mmol/L), and high glucose level with ibrolipim treatment.HUVEC-12 activity or injury was assayed by methyl thiazolyl tetrazolium (MTT).The ET-1 concentrations were evaluated by radioimmunoassay.The expression of vWF in the conditioned media was tested by enzyme-linked immunosorbent assay (ELISA).Endothelial dysfunction was identified by the expression of ET-1 and vWF through reverse transcription polymerase chain reaction (RT-PCR).The protein content of ET-1 and vWF were evaluated by cell immunofluorescence.ResultsHigh glucose condition significantly weakened cell viability, and increased the expression of ET-1 and vWF.Ibrolipim treatment significantly attenuated these alterations of endothelial dysfunction.The low er con-cen trations (2, 4, 8 μmol/L) of ibrolipim improved cell viability, down-regulated the expression of ET-1 and vWF, and attenuated the cytotoxicity, however, higher concentration (16, 32 μmol/L) of ibrolipim aggravated the damage of HUVEC-12 cultured under high glucose level.ConclusionIbrolipim at low concentration can inhibit high glucose-induced endothelial dysfunction of cultured HUVEC-12, which may be related to the alternation of ET-1 and vWF expression.

Abstract:Aim To explore the effect of Shuxuetong injection combined with captopril on elderly hypertension patients plasma endothelin(ET) and nitric oxide(NO) contents. Methods Elderly patients with hypertension were randomly divided into treatment group(n=40) and control group(n=36).Treatment group was treated with Shuxuetong injection and captopril,while control group was only given captopril,with 14d as a period course.The change of circadian rhythm of blood pressure,plasma ET and NO after treated for one course was observed. Results The treatment group was better than control group in antihypertensive effects(P<0.01).The improvement of rhythm diurnal variation by traditional and western medicine was better than control group in elderly hypertension.Compared with control group,treatment groups change of plasma ET and NO level had significant difference(P<0.05). Conclusions The combination of Shuxuetong injection and captopril can effectively improve elderly patients circadian rhythm of blood pressure,increase the NO contents and decrease plasma ET.It has a better effect of longtime hypotensive,and it is worth in clinical widely.