AIMTo investigate the effect of endogenous endothelin-1 (ET-1) on cardiomyocyte apoptosis induced by hypoxia and its possible mechanism.

METHODSCultured neonatal rat cardiomyocytes were divided into control group and ET receptor antagonist group. Control group was given DMEM only and ET receptor antagonist group was treated with ET receptor subtype A (ET(A)) receptor antagonist BQ610 and BQ123 or ET(B) receptor antagonist BQ788 and subjected to hypoxia for 24 h. The presence of apoptosis in cardiomyocytes was evaluated by TUNEL analysis and flow cytometry (FCM).

RESULTSTUNEL analysis showed that the percentage of positive apoptotic cells in BQ610 5 micromol/L group was 13.2% +/- 3.7%, significantly lower than that in hypoxia group (24.2% +/- 2.2%, P < 0.01). FCM showed that BQ123 (0.04, 0.2 and 1.0 micromol/L) inhibited hypoxia-induced cardiomyocyte apoptosis and increased cardiomyocyte survival rate in a dose-dependent manner, while BQ788 did not show such effects.

CONCLUSIONThese findings suggest that endogenous ET-1 aggravates hypoxia-induced cardiomyocyte apoptosis and this effect is mediated through ET(A) receptor-dependent pathways.

Animals ; Animals, Newborn ; Apoptosis ; Cell Hypoxia ; Cells, Cultured ; Endothelin A Receptor Antagonists ; Endothelin B Receptor Antagonists ; Endothelin-1 ; physiology ; Myocytes, Cardiac ; metabolism ; pathology ; Rats ; Rats, Sprague-Dawley

Three-dimensional pharmacophore models were generated for AT1 and ET(A) receptors based on highly selective AT1 and ET(A) antagonists using the program Catalyst/HipHop. Both the best pharmacophore model for selective AT1 antagonists (Hypo-AT(1)-7) and ETA antagonists (Hypo-ET(A)-1) were obtained through a careful validation process. All five features contained in Hypo-AT(1)-7 and Hypo-ET(A)-1 (hydrogen-bond acceptor (A), hydrophobic aliphatic (Z), negative ionizable (N), ring aromatic (R), and hydrophobic aromatic (Y)) seem to be essential for antagonists in terms of binding activity. Dual AT1 and ET(A) receptor antagonists (DARAs) can map to both Hypo-AT(1)-7 and Hypo-ET(A)-1, separately. Comparison of Hypo-AT(1)-7 and Hypo-ET(A)-1, not only AT1 and ET(A) antagonist pharmacophore models consist of essential features necessary for compounds to be highly active and selective toward their corresponding receptor, but also have something in common. The results in this study will act as a valuable tool for designing and researching structural relationship of novel dual AT1 and ET(A) receptor antagonists.
Angiotensin II Type 1 Receptor Blockers ; chemistry ; Drug Design ; Endothelin Receptor Antagonists ; Models, Molecular ; Molecular Conformation

OBJECTIVETo study the expression of ET receptor and the apoptosis after intervened with ET receptor antagonist in androgen-independent prostate cancer.

METHODSPC3, an androgen-independent prostate cancer cell line, was used. The expression of ETA and ETB receptor in PC3 was measured through RT-PCR. After intervened with selective ETA and ETB receptor antagonist, the apoptosis in PC3 was studied through flow cytometry and electron microscope.

RESULTSClear signal was obtained in PC3 for ETA receptor mRNA transcript, while the signal for ETB receptor mRNA transcript was very weak. The expression of ETA receptor mRNA was obviously reduced and the apoptosis of PC3 cell was observed after intervened with selective ETA receptor antagonist. There was no change after intervened with selective ETB receptor antagonist.

CONCLUSIONET-1 exerts its effects through the ETA receptor subtype and ETB receptor is silenced in PC3. The expression of ETA was reduced and the apoptosis was observed in PC3 when ETA receptor was blocked. It was dose-dependent.

Androgens ; physiology ; Apoptosis ; drug effects ; physiology ; Endothelin A Receptor Antagonists ; Endothelin B Receptor Antagonists ; Endothelin-1 ; physiology ; Humans ; In Vitro Techniques ; Male ; Neoplasms, Hormone-Dependent ; pathology ; Oligopeptides ; administration & dosage ; Peptides, Cyclic ; administration & dosage ; Piperidines ; administration & dosage ; Prostatic Neoplasms ; pathology ; physiopathology ; Receptor, Endothelin A ; metabolism ; physiology ; Receptor, Endothelin B ; metabolism ; physiology

OBJECTIVETo investigate the anti-tumor effect of the endothelin A receptor antagonist BQ123 on human prostate cancer cell line PC-3M in vitro by observing its impact on the proliferation and apoptosis of human prostate cancer cells.

METHODSThe inhibiting effect of BQ123 on the proliferation of PC-3M cells was observed by MTT assay, erosion trace test and Transwell chamber chemotaxis assay, and its induction of their apoptosis determined by Annexin V-FITC/PI staining and cytometry.

RESULTSBQ123 exhibited increased inhibition of PC-3M cells in a time-dependent manner, with inhibition rates of 22.32%, 44.88% and 64.47% at 24 h, 48 h and 72 h, respectively (P < 0.05). The migration distances of the PC-3M cells in the BQ123 group were (103.42 +/- 75.63) microm, (243.75 +/- 121.53) microm and (422.07 +/- 36.01) microm at 12 h, 24 h and 48 h, obviously lower than (162.93 +/- 19.87) microm, (317.19 +/- 43.19) microm and (692.74 +/- 40.84) microm in the control group (P < 0.05). The number of the PC-3M cells that invaded the inferior chamber in the BQ123 group was (79.2 +/- 9.58), significantly decreased as compared with (92.6 +/- 5.94) in the control (P < 0.05). The apoptosis rate of PC-3M exposed to BQ123 was (15.03 +/- 0.93)%, significantly higher than (9.38 +/- 1.37)% in the control (P < 0.05). The ratio of PC-3M cells in different cycles showed no significant differences.

CONCLUSIONBQ123 inhibits the proliferation of PC-3M cells and induces their apoptosis in vitro, which may give a new idea on the studies of prostate cancer therapies.

Apoptosis ; drug effects ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Endothelin A Receptor Antagonists ; Humans ; Male ; Peptides, Cyclic ; pharmacology ; Prostatic Neoplasms

Recently several kinds of new antihypertensive agents were introduced. Diuretics such as indapamide, metyrazone and eprelerone have less side effects compared to thiazide, and have an effect in renal insufficiency. Carvedilol, combined alpha- and beta- adrenergic blocker, has a vasodilating property and an effect on heart failure. The lipid soluble third generation calcium antagonists such as amlodipine, lacidipine and lercardipine are slow onset and long acting and have less side effects, which provide continued effect even if daily doses are missed. Multiple angiotensin converting inhibitors and angiotensin receptor blockers, and the specific aldosterone antagonist eprenolone to block renin-angiotensin-aldosterone system are now available. Additionally new class antihypertensive drugs such as the vasopeptidase inhibitor, the endothelin receptor blocker and the renin inhibitor have been under investigation and shown favorable clinical results, and will be available for clinical use soon.
Adrenergic Antagonists ; Aldosterone ; Amlodipine ; Angiotensin Receptor Antagonists ; Angiotensins ; Antihypertensive Agents ; Calcium ; Diuretics ; Heart Failure ; Hypertension* ; Indapamide ; Receptors, Endothelin ; Renal Insufficiency ; Renin ; Renin-Angiotensin System

Proteinuria is a cardinal manifestation of renal disease and has been proposed to promote progression of renal disease. Proteinuria develops in 9~41% of transplant recipients, and is diagnosed by routine urinalysis, urine protein to creatinine ratio, or 24-hour urine protein collection. Protein excretion of >200 mg/24 h is considered abnormal. The etiology of post-transplant proteinuria is diverse, including allograft rejection, recurrent or de novo glomerulonephritis, cyclosporine A nephrotoxicity, conversion to sirolimus, and chronic allograft nephropathy, which is the most common. Transplant renal biopsy is required to confirm the cause of proteinuria, and a combination of two or more of the transplant pathological categories can be present. High-grade proteinuria is believed to mediate progressive renal damage by conferring to proximal tubular epithelial cells with increased production of endothelin-1, chemokines such as monocyte chemoattractant protein-1 and cytokines, all of which promote interstitial fibrosis. It has been reported that proteinuria after renal transplantation affected not only graft survival but also patient survival. In proteinuric recipients, both the cardiovascular and noncardiovascular death risks seem to be significantly increased compared with nonproteinuric recipients. Low-grade (<1 g/24 h) proteinuria 1 year after transplantation is also associated with graft loss. The treatments for proteinuria are blood pressure control, and the use of angiotensin-converting enzyme inhibitor and/or angiotensin II receptor blockers therapy. Several options that are able to reduce proteinuia, including nondihydropyridine calcium channel blocker or aldosterone antagonists are also available. In conclusion, post-transplant proteinuria is a sensitive marker of graft dysfunction, correlated both to graft failure and to patient death. Appropriate management guided by proven cause and antiproteinuric treatments may improve the outcome.
Allografts ; Angiotensin Receptor Antagonists ; Biopsy ; Blood Pressure ; Calcium Channels ; Chemokine CCL2 ; Chemokines ; Creatinine ; Cyclosporine ; Cytokines ; Endothelin-1 ; Epithelial Cells ; Fibrosis ; Glomerulonephritis ; Graft Survival ; Humans ; Kidney Transplantation ; Mineralocorticoid Receptor Antagonists ; Proteinuria* ; Sirolimus ; Transplantation ; Transplants ; Urinalysis

BACKGROUNDIt has been shown that neurohumoral factors other than mechanical obstruction are involved in the pathophysiology of acute pulmonary thromboembolism (APTE). The aim of this study was to investigate the effects of thrombolytic drugs, a selective endothelin-1 receptor (ET-1R) antagonist alone or their combination on APTE in a canine model.

METHODSTwenty dogs were randomly assigned to five groups: sham, model, urokinase (UK), BQ123, and combination (UK plus BQ123). The dogs in the sham group underwent sham surgery. APTE was induced in the other four groups by intravenous injection of autologous blood clots. Dogs in the UK, BQ123 and combination groups received UK, BQ123 (a selective ET-1R antagonist), or UK plus BQ123, respectively. The dogs in the model group were given saline. Mean pulmonary artery pressure (mPAP), serum concentrations of ET-1, thromboxane (TXB2), and tumor necrosis factor (TNF)-alpha were determined at different time points following the induction of APTE.

RESULTSUK and BQ123 alone markedly decreased mPAP in APTE. By comparison, the reduction was more significant in the combination group. Compared with the sham group ((-0.90 +/- 0.61) mmHg), mPAP increased by (7.44 +/- 1.04), (3.42 +/- 1.12) and (1.14 +/- 0.55) mmHg in the model group, UK alone and BQ123 alone groups, respectively, and decreased by (2.24 +/- 0.67) mmHg in the combination group (P < 0.01). Serum ET-1 concentrations in the BQ123 and combination groups were (52.95 +/- 8.53) and (74.42 +/- 10.27) pg/ml, respectively, and were significantly lower than those in the model and UK groups ((84.56 +/- 7.44) and (97.66 +/- 8.31) pg/ml respectively; P < 0.01). Serum TNF-alpha concentrations were significantly lower in the BQ123 group than in the model, UK and combination groups (P < 0.05).

CONCLUSIONSOur results indicate that the selective ET-1R antagonist BQ123 not only reduces the increase of mPAP and serum ET-1 level, but also inhibits the production of TNF-alpha, and attenuates the local inflammatory response induced by APTE. Selective ET-1R antagonists may be beneficial to the treatment of APTE, particularly when used in combination with a thrombolytic agent.

Animals ; Dogs ; Endothelin A Receptor Antagonists ; Endothelin-1 ; blood ; Fibrinolytic Agents ; therapeutic use ; Peptides, Cyclic ; therapeutic use ; Pulmonary Embolism ; blood ; drug therapy ; pathology ; Random Allocation ; Thromboxanes ; blood ; Tumor Necrosis Factor-alpha ; blood

BACKGROUND AND OBJECTIVES: Elevated endothelin (ET)-1 level is strongly correlated with the pathogenesis of pulmonary arterial hypertension (PAH). Expression level of nicotinamide adenine dinucleotide phosphate oxidase (NOX) 4 is increased in the PAH patients. Ambrisentan, a selective endothelin receptor A (ERA) antagonist, is widely used in PAH therapy. The current study was undertaken to evaluate the effects of ambrisentan treatment in the monocrotaline (MCT)-induced PAH rat model. METHODS: Rats were categorized into control group (C), monocrotaline group (M) and ambrisentan group (Am). The M and Am were subcutaneously injected 60 mg/kg MCT at day 0, and in Am, ambrisentan was orally administered the day after MCT injection for 4 weeks. The right ventricle (RV) pressure was measured and pathological changes of the lung tissues were observed by Victoria blue staining. Protein expressions of ET-1, ERA, endothelial nitric oxide synthase (eNOS) and NOX4 were confirmed by western blot analysis. RESULTS: Ambrisentan treatment resulted in a recovery of the body weight and RV/left ventricle+septum at week 4. The RV pressure was lowered at weeks 2 and 4 after ambrisentan administration. Medial wall thickening of pulmonary arterioles and the number of intra-acinar arteries were also attenuated by ambrisentan at week 4. Protein expression levels of ET-1 and eNOS were recovered at weeks 2 and 4, and ERA levels recovered at week 4. CONCLUSIONS: Ambrisentan administration resulted in the recovery of ET-1, ERA and eNOS protein expression levels in the PAH model. However, the expression level of NOX4 remained unaffected after ambrisentan treatment.
Animals ; Arteries ; Arterioles ; Blotting, Western ; Body Weight ; Endothelin Receptor Antagonists ; Endothelins ; Gene Expression ; Heart Ventricles ; Humans ; Hypertension ; Hypertension, Pulmonary ; Lung ; Models, Animal ; Monocrotaline ; NADP ; NADPH Oxidase ; Nitric Oxide Synthase Type III ; Oxidoreductases ; Rats ; Receptors, Endothelin ; Victoria

OBJECTIVETo investigate the effect of sodium ferulate (SF) on diabetic nephropathy (DN).

METHODSForty-eight DN patients of early stage and 54 DN patients of clinical stage were randomly divided into two groups, the conventional treatment group and the SF treatment group. Indexes, including urinary albumin excretion rate (UAER), serum endothelin (ET), blood urea nitrogen (BUN), serum creatinine (Scr) and fasting blood glucose (FBG) were observed.

RESULTSThe levels of UAER, BUN and ET were decreased in all DN patients, either early stage or clinical stage, after treated with SF for 4 weeks (P < 0.05, P < 0.01), but changed insignificantly in those treated with conventional treatment.

CONCLUSIONSF can decrease the levels of UAER and BUN in DN patients, the mechanism may relate with the decreasing of ET production and antagonizing to the binding of ET with its receptors.

Adult ; Aged ; Coumaric Acids ; therapeutic use ; Diabetes Mellitus, Type 2 ; drug therapy ; Diabetic Nephropathies ; drug therapy ; Endothelin Receptor Antagonists ; Female ; Humans ; Male ; Middle Aged ; Phytotherapy

OBJECTIVETo investigate the long-term effect of bosentan on outcome in patients after Fontan operation.

METHODSPatients after Fontan surgery were randomly divided into bosentan group (B, n = 16) and control group (C, n = 23). Bosentan was applied within 7 days after Fontan surgery as follows: at the first month, 7.8125 mg Bid for patients with body weight ≤ 10 kg; 15.625 mg Bid for patients with body weight between 10-20 kg; 31.25 mg Bid for patients with body weight 20-30 kg and 62.5 mg Bid for patients with body weight > 30 kg. At the second month, the bosentan dose was doubled and Bosentan therapy was continued for more than 1 year. Group C didn't take drugs affecting pulmonary artery pressure. All patients were followed up for 2 years and incidence of mortality, protein losing enteropathy, pulmonary arteriovenous fistulae, 6-minute walk test, heart function were compared between the two groups.

RESULTSAfter 2 years, mortality tended to be lower in group B compared to group C [6.25% (1/16) vs. 21.8% (5/23), P > 0.05]. Incidence of pulmonary arteriovenous fistulae and protein losing enteropathy were significantly lower in group B than in group C (6.25% vs. 34.78%, P = 0.01;6.25% vs. 39.13%, P = 0.02, respectively) . The results of 6-minute walk test[ (485 ± 44) m vs. (302 ± 183) m] and heart function in group B (3 NYHA III/IV patients in group B vs. 14 NYHA III/IV patients in group C, all P < 0.05) were all better than group C. The concentrations of vasoactive factors such as brain natriuretic peptide (BNP, 279.07 ± 128.17 vs. 457.67 ± 221.30), endothelin (ET, 3.30 ± 0.61 vs. 4.98 ± 1.24) and thromboxane (TXA2, 97.2 ± 24.0 vs. 163.22 ± 24.4) were also significantly lower in group B than in group C (all P < 0.05). Prostacyclin (PGI2) level and incidence of arrhythmias were similar between the two groups. There was no thrombotic event in both groups during follow up.

CONCLUSIONBosentan trerapy in patients post Fontan operation could reduce the incidence of pulmonary arteriovenous fistulae and protein losing enteropathy and improve heart function.

Adolescent ; Child ; Child, Preschool ; Endothelin Receptor Antagonists ; therapeutic use ; Female ; Fontan Procedure ; Humans ; Hypertension, Pulmonary ; drug therapy ; Male ; Prognosis ; Sulfonamides ; therapeutic use ; Treatment Outcome