Associations between thromboxane A synthase 1 gene polymorphisms and the risk of ischemic stroke in a Chinese Han population

Thromboxane A synthase 1 （TBXAS1） catalyses the synthesis of thromboxane A2 （TXA2）, which plays an important role in the pathogenesis of ischemic stroke. Thus, the TBXAS1 gene was investigated as a candidate gene involved in the formation of atherosclerosis. This case-control study collected peripheral blood specimens and clinical data of 370 ischemic stroke patients and 340 healthy controls in the Northern Chinese Han population from October 2010 to May 2011. Two TBXAS1 single-nucleotide polymorphisms, rs2267682 and rs10487667, were analyzed using a SNaPshot Multiplex sequencing assay to explore the relationships between the single-nucleotide polymorphisms in TBXAS1 and ischemic stroke. The TT genotype frequency and T allele frequency of rs2267682 in the patients with ischemic stroke were significantly higher than those in the controls （P 〈 0.01 and P = 0.02）. Furthermore, compared with the GG ＋ GT genotype, the TT rs2267682 genotype was associated with increased risk of ischemic stroke （odds ratio （OR） = 1.80, 95% confidence interval （CI）： 1.16–2.79, P 〈 0.01）. Multivariate logistic analysis with adjustments for confounding factors revealed that rs2267682 was still associated with ischemic stroke （OR = 1.94,95% CI ： 1.13–3.33, P = 0.02）. The frequency of the T-G haplotype in the patients was significantly higher than that in the controls according haplotype analysis （OR = 1.49, 95% CI： 1.10–2.00, P 〈 0.01）. These data reveal that the rs2267682 TBXAS1 polymorphism is associated with ischemic stroke. The TT genotype of TBXAS1 and T allele of rs2267682 increase susceptibility to ischemic stroke in this Northern Chinese Han population. The protocol has been registered with the Chinese Clinical Trial Registry （registration number： ChiCTR-COC-17013559）.

Platelet thromboxane(11-dehydro-Thromboxane B_2) and aspirin response in patients with diabetes and coronary artery disease

Aspirin(ASA) irreversibly inhibits platelet cyclooxygenase-1(COX-1) leading to decreased thromboxane-mediated platelet activation. The effect of ASA ingestion on thromboxane generation was evaluated in patients with diabetes(DM) and cardiovascular disease. Thromboxane inhibition was assessed by measuring the urinary excretion of 11-dehydro-thromboxane B2(11dhTxB2), a stable metabolite of thromboxane A2. The mean baseline urinary 11dhTxB2 of DM was 69.6% higher than healthy controls(P = 0.024): female subjects(DM and controls) had 50.9% higher baseline 11dhTxB2 than males(P = 0.0004), while age or disease duration had no influence. Daily ASA ingestion inhibited urinary 11dhTxB2 in both DM(71.7%) and controls(75.1%, P < 0.0001). Using a pre-established cut-off of 1500 pg/mg of urinary 11dhTxB2, there were twice as many ASA poor responders(ASA "resistant") in DM than in controls(14.8% and 8.4%, respectively). The rate of ASA poor responders in two populations of acute coronary syndrome(ACS) patients was 28.6 and 28.7%, in spite of a significant(81.6%) inhibition of urinary 11dhTxB2(P < 0.0001). Both baseline 11dhTxB2 levels and rate of poor ASA responders were significantly higher in DM and ACS compared to controls. Underlying systemic oxidative inflammation may maintain platelet function in atherosclerotic cardiovascular disease irrespective of COX-1 pathway inhibition and/or increase systemic generation of thromboxane from non-platelet sources.

Changes of nitric oxide and endothelin, thromboxane A2 and prostaglandin in cirrhotic patients undergoing liver transplantation

AIM： To investigate the perioperative changes of nitric oxide （NO） and endothelin （ET）, thromboxane A2 （TXA2） and prostaglandin （PGI2） during liver transplantation in end-stage liver disease patients. METHODS： Twenty-seven patients with end-stage cirrhosis undergoing liver transplantation were enrolled in this prospective study. Blood samples were obtained from superior vena at five different surgical stages. Plasma concentrations of nitrate and nitrite were determined to reflect plasma NO levels. Plasma levels of ET-1, 6-keto-PGF1 alpha and thromboxane B2 （TXB2）, the latter two being stable metabolites of PGI2 and TXA2 respectively, were measured.RESULTS： The NO level decreased significantly after vascular cross-clamping and increased significantly at 30 rain after reperfusion. While the ET levels at 30 rain after clamping and after reperfusion were significantly elevated. The ratio of NO/ET decreased significantly at 30 rain after vascular cross-clamping and at the end of surgery. The PGI2 level and the TXA2 during liver transplantation were significantly higher than the baseline level, but the ratio of TXA2/PGI2 decreased significantly at 30 rain after clamping. CONCLUSION： NO/ET and TXA2/PGI2 change during liver transplantation. Although the precise mechanism remains unknown, they may play a role in the pathobiology of a variety of liver transplant-relevant processes.

Antithrombotic Effects of BM-13505,a ThromboxaneReceptor Antagonist

BM-13 505 is a new type of thromboxane receptor antagonist developed firstabfoad and synthesized in our school.wita modife method recently。The resultS of our study showed that the occlusion time of carotid artery in experimental thrombosis rats was prolonged by BM-13505,0.45 and 0.23 mglkg iv fP<0.00 1 and <0.01 respectively).B·13505 2 mgjkg iv ef fectively prevented the cerebral thrombosis caused by AA 4 mg/kg in rats(P<0.01) BM-13505 10 mg/kg ip prevented the AA-induced pulmonary thrombosis in mice(P<0.01).Tail bleeding time of mice was prolonged by this dru.BM-13505 significantly inhibited the AA-induced rabbit platelet aggregation,with an IC￣(50) of0.17 μmol/L; ADp-and collagen-induced aggregations were not affected.TXB_2 level in platelets and that in mice plasma were decreased by BM-13505,but cAMP level inplatelets was not affected. BM-13505 may be possibly developed into a useful anti-platelet and anti-thromboti c drug。

Effects of thromboxane and prostacyclin imbalance on hemodynamics and hemorrheology in severely burn patients

Fifty-seven bum patients were dosdy observed for 28 d postburn.In general,plasma levelof thromboxane B2（TXB2）,6-keto-PGFlx and TXB2/6-keto-PGFlx ratio all rose up abruptly tothe peak in the first half day after burns and then declined gradually.However the patterns of theirchanges were different:6-keto-PGFlx returned to the control level in the 2nd day postburn,remained in a higher level than the control even in the 5th day postburn,and the increase ofTXB2/6-keto-PGFlα ratio was especially pronounced in the first 3 d postbum.It was also shownthat the changes of hemodynamics and hemorrheology occurred simultaneously with the imbalanceof thromboxane and prcstacyclin in the early postburn stage.The extent of the imbalance accordedwith the severity of hemodynamical and hemorrheological changes and was closely correlated withthe changes with the stroke volume,cardiac output,systemic vascular resistance,circulatory plateletaggregate ratio,platelet count and blood vinery.These findings suggest that the imbalance be-tween thromboxane and prostacyclin plays an important role in the changes of hemodynamics andhemorrheology in severe burn cases.

Diet Rich in Saturated Fat Decreases the Ratio of Thromboxane/prostacyclin in Healthy Men

Objective To investigate the effect of dietary saturated fat (SFA) from animal sources on the urine excretion 11-dehydro thromboxane 62 (TXB2) and 6-keto prostaglandin F la (PGF la) in 27 healthy free-living male subjects aged 30 to 55 years. Methods It was a randomized crossover design. Each volunteer was randomly assigned to one of the two diets (high fat and low fat) for a period of 4 weeks, after which each subject resumed his usual diet for 2 weeks as a 'wash-out period', before being assigned to the other diet for an additional 4 weeks. Results Serum proportion of 20:4n-6 was 5% lower in the high fat (6.2% of total fatty acid) than in the low fat diet (6.5% of total fatty acid), which was associated with a significantly decreased ratio of the urinary excretion 11-dehydro TXB2 to 6-keto PGF lα (P<0.05). However, there was no significant fall in the absolute urinary excretion of 11-dehydro TXB2. Conclusions Diet rich in SFA from animal sources may influence TXA2 formation via effect on tissue proportion of 20:4n-6.

Changes of thromboxane and prostacyclin in the pathogenesis of multiple organ failure in severe burns

Fifty-seven severely burned patients were divided into 2 groups:16 withmultiple organ failure（MOF）,and 41 without MOF.It was found that the levelof thromboxane B2（TXB2）and the ratio between TXB2 and 6-keto-prostaglandinF1α(TBX2/6-keto-PGF1α)in plasma and in visceral tissues were increased and re-mained significantly high in the first 5～7 d postburn in patients with MOF but notso in those without MOF.The circulatory platelet aggregate ratio（CPAR）wasmarkedly decreased in the same period in MOF group.Myocardial enzymes（CPK,LDH,and GOT）were markedly increased in the first 3d and remainedsignificantly high within 7 d postburn.Degeneration,structural destruction,edema,hemorrhage and thrombosis were revealed in cardiac,pulmonary,renal andhepatic tissues succumbing to functional failure.Thirteen out of the 16 cases de-veloped MOF during the 3rd to 7th day posthurn and 11 died in that period.These findings substantiate that persistent increase of thromboxane andthromboxane/prostacyclin ratio is closely related to the origin and development ofMOF after burn injury.

Inhibition of Cyclooxygenase and Thromboxane Synthetase on Oxygen Delivery and Utilization in Acute Respiratory Failure Canine

The puapose of this study was to evaluate the effects of cyclooxygenase inhibitor (Ibuprofen)and thromboxane synthetase inhibitor (OKY-046) on oxygen metabolism in acute respiratory failure.Intratracheal instillation of hydrochloric acid was produced in 18 dogs, six dogs were pretreated with ibuprofen (IBU), six dogs with OKY-046 (OKY),and the remaindere used as control (CTR). After acid aspiration oxygen delivery (DO_2) fell in all groups as a results of decreased PaO_2 and cardiac output.However, oxygen consumption (VO_2)was maintained in all animals by the end of experiments except in CTR group. Arterial oxygen content maintained at baseline level throughout the experiments in IBU group. Meanwhile a significantly decreased mixed venous oxygen tension was found in OKY group after acid challenge. Liner regression of _vO_2 and DO_2 was confirmed in both CTR and OKY group. However,the dependent relationship between VO_2 and DO_2 was not identified in IBU group, which may indicate that the body oxygen metabolism was maintained rather well in acute rcspiratory failure dogs treated with ibuproten.

RELATION OF MALIGNANT TUMOR TO PROSTACYCLIN AND THROMBOXANE

The level of 6-keto-PGF1αand thromboxane B2(TXB2) in Plasma was determined with radioimmunoassay in 58 normal subjects and 92 Patients with various cancers(including lung,hepatic,gastric,esophageal and pancreatic carcinoma).The results showed that 6-keto-PGF1α.In plasma was 10.21±2.75 Pg/ml,and TXB2 146.03±37.31 Pg/ml in normal individuals,the ratio of 6-keto-PGF1α to TXB2 was 0.07;while in cancer Patients 6-keto-PGF1αwas 27.5±16.9 Pg/ml and TXB2 315.4±173.4 Pg/ml, the ratio of 6-keto-PGF1αto TXB2 was 0.08.The values of 6-keto-PGF1αand TXB2 in plasma of cancer patients were 2.69 folds and 2.16 folds higher than that of the two groups,respectively.The difference between the two groups was statistically significant(P<0.01).It indicates that the synthesis and release of PGI2 and TXA2 of cancer tissues increases greatly as compared to the normals.The study also revealed that the size of tumor,metastasis and histological classification had no obvious relation to PGs.

Effect of Intra-arachnoid Space Perfusion on Thromboxane A and Prostacycline in Experimental Spinal Cord Injury

In order to understand the relation between TXA2- PGI2 and secondary trauma and the effect of intra-arachnoid perfusion of dexamethasone and verapamil on alteration of TXA,-PGI, following spinal cord injury, TXB2 and 6-keto-PGFconcentration and pathological changes in injured site 1, 2, 4 and 6 h after injury were studied using a rabbit spinal cord injury model by Allen's weight drop method.

Effects of procainamide on adenosine diphosphate-induced platelet aggregation and thromboxane B_2 production in rabbits in vitro

Turbidimetry and radioimmunoassay were used to study the effects of procainamide (PA ) onadenosine diphosphate (ADP)-induced rabbit platelet aggregation and thromboxane B2 (TXB2) production invitro. PA 8. 5--544. 0 μmol L-1 inhibited ADP-induced platelet aggregation and TXB2 production, and theinhibition rates were 26. 7% -- 66. 7 % and 21. 4 % -- 70. 1 %, respectively. There was positive correlation between PA concentration and its efficiency in inhibiting the platelet aggregation and TXB2 production, and alsobetween the inhibition rates of platelet aggregation and that of TXB2 production. The three linear equationsand main parameters were The results indicate that PA could significantly inhibit ADP--induced platelet aggregation and TXB2 production in rabbits.

Apigenin is an anoikis sensitizer with strong anti-metastatic properties in experimental breast cancer

Loss of susceptibility to anoikis signals is a crucial step in metastasis.Anoikis resistance therefore represents a promising adjuvant therapeutic target for cancer management.In this study,we have conducted a rationalized screening to search for novel leading anoikis sensitizer from daily foods.Among 19 tested dietary phytochemicals,the best results were obtained with apigenin,a natural component of celery.Phenotypically,apigenin sensitized breast cancer cells to anoikis,lowered the number of circulating tumor cells,and protected against breast cancer metastasis to lung in mice.Mechanistically,we demonstrated that the thromboxane A_(2)(TXA_(2))-TXA_(2)receptor(TP)axis has a critical role in acquired anoikis resistance by activating PI3K-Akt signaling pathway.Blockage of TXA_(2)signaling up-regulated p53 as well as its target gene p21,caused a G1 phase arrest,and finally led to apoptosis in breast cancer cells.TXA_(2)level was positively correlated with breast cancer cell anoikis rate,and apigenin significantly inhibited TXA_(2)biosynthesis in vitro and in vivo.Collectively,we identified apigenin as a potent anoikis sensitizer with anti-metastatic properties in a mouse model of breast cancer,and these findings might provide a rationale for introducing apigenin supplementation to breast cancer patients.

The Effect of Tetramethylpyrazine on Tumor Necrosis Factor-α,Thromboxane A_2 and Prostecyclin in Cerebrospinal Fluidof Rabbits with Bacterial Meningitis

This study aimed to evaluate the effect of tetramethylpyrazine in treating bacterial meningi-tis . Experimental model of rabbit meningitis was induced by intracisternal inoculation ot 2 x 107 colony-formingunits of Escherichia Coli and tumor necrosis factor-a, thromboxane B2 and 6-keto-prostagladin F1a concentra-tions in cerebrospinal fluid of rabbits in different treatment groups were measured at 24 hrs, 27 hrs and 30 hrsafter infection. Results showed that tetramethylpyrazine could significantly lower the concentrations of tumornecrosis factor-a and thromboxane B2 in cerebrospinal fluid. Administration of both tetramethylpyrazine andampicillin could attenuate the antibiotic-induced rapid release of the 2 intlammatory mediators .

Thromboxane A2 receptor contributes to the activation of rat pancreatic stellate cells induced by 8-epi-prostaglandin F2α

Background:Pancreatic stellate cells(PSCs)activation plays a critical role in the development of chronic pancreatitis.Previous studies confirmed that thromboxane A2 receptor(TxA2r)was overexpressed in activated PSCs in rats.The purpose of this study was to investigate the role of TxA2r in the activation of PSCs induced by 8-epi-prostaglandin F2α(8-epi-PGF2α).Methods:TxA2r expression in both quiescent and activated PSCs was detected by immunocytochemistry and immunoblot assay.Isolated PSCs were treated with 8-epi-PGF2α(10^-6,10^-7,10^-8 mol/L)for 48 h,and SQ29548(10^-4,10^-6,and 10^-7 mol/L),a TxA2r-specific antagonist,for 48 h,respectively,to identify the drug concentration with the best biological effect and the least cytotoxicity.Then isolated PSCs were treated with SQ29548(10^-4 mol/L)for 2 h,followed by 10^-7 mol/L 8-epi-PGF2α for 48 h.Real-time polymerase chain reaction was performed to detect the messenger RNA(mRNA)levels of a-smooth muscle actin(a-SMA)and collagen I.Comparisons between the groups were performed using Student’s t test.Results:TxA2r was up-regulated in activated PSCs in vitro compared with quiescent PSCs(all P<0.001).Compared with the control group,different concentrations of 8-epi-PGF2α significantly increased mRNA levels of a-SMA(10^-6 mol/L:2.23±0.18 vs.1.00±0.07,t=10.70,P<0.001;10^-7 mol/L:2.91±0.29 vs.1.01±0.08,t=10.83,P<0.001;10^-8 mol/L,1.67±0.07 vs.1.00±0.08,t=11.40,P<0.001)and collagen I(10^-6 mol/L:2.68±0.09 vs.1.00±0.07,t=24.94,P<0.001;10^-7 mol/L:2.12±0.29 vs.1.01±0.12,t=6.08,P<0.001;10^-8 mol/L:1.46±0.15 vs.1.00±0.05,t=4.93,P=0.008).However,different concentrations of SQ29548 all significantly reduced the expression of collagen I(10^-4 mol/L:0.55±0.07 vs.1.00±0.07,t=10.47,P<0.001;10^-6 mol/L:0.56±0.10 vs.1.00±0.07,t=6.185,P<0.001;10^-7 mol/L:0.27±0.04 vs.1.00±0.07,t=15.41,P<0.001)and a-SMA(10^-4 mol/L:0.06±0.01 vs.1.00±0.11,t=15.17,P<0.001;10^-6 mol/L:0.28±0.03 vs.1.00±0.11,t=11.29,P<0.001;10^-7 mol/L:0.14±0.04 vs.1.00±0.11,t=12.86,P<0.001).After being treated with SQ29548(10^-4 mol/L)and then 8-epi-PGF2α(10^-7 mol/L),the mRNA levels of a-SMA(0.20±0.08 vs.1.00±0.00,t=17.46,P<0.001)and collagen I(0.69±0.13 vs.1.00±0.00,t=4.20,P=0.014)in PSCs were significantly lower than those of the control group.Conclusions:The results show that 8-epi-PGF2α promoted PSCs activation,while SQ29548 inhibited PSCs activation induced by 8-epi-PGF2α.The result indicated that TxA2r plays an important role during PSC activation and collagen synthesis induced by 8-epi-PGF2α in vitro.This receptor may provide a potential target for more effective antioxidant therapy for pancreatic fibrosis.

Effects of Acupuncture at 7-9 am and 3-5 pm on Plasma Thromboxane and Prostaglandin in Patients with Ischemic Cerebrovascular Disease

Objective:To observe the effects of acupuncture at different times on plasma thromboxane(TXB2) and prostaglandin 6-Keto-PGF1a(6-K-P) in patients with ischemic cerebrovascular disease.Methods:Totally 90 patients were randomly divided into a group acupunctured at 7-9 am,a group acupunctured at 3-5 pm and a drug control group,with 30 cases in each group.The contents of plasma TXB2 and 6-K-P from venous blood before treatment were compared with those 15 days after treatment.Results:The plasma TXB2 levels of the two acupuncture groups were obviously lower than those before treatment(P<0.05,P<0.01) ,but the 6-K-P levels of both the acupuncture groups were remarkably higher than those before treatment(P<0.05,P<0.01) . And the TXB2 level in the 3-5 pm acupuncture group was obviously lower than that in the 7-9 am acupuncture group(P<0.05) ,and the 6-K-P level of the former was obviously higher than that of the latter(P<0.05) .Conclusion:Acupuncture can promote functional recovery in patients with ischemic cerebrovascular disease and enhance their survival quality.

Effects of Oenethera Oil on Plasma Lipid,Thromboxane A2 and AngiotensinⅡof Chronic Renal Insufficiency

Oenethera biennis oil was administered (6 g per day) in 23 chronic renal insufficiency pa-tients over a 4 week period. Changes of serum creatinine, creatinine clearance, plasma lipid, renin activity,and angiatensin , urinary thromboxane B2 and 6-keto-prostaglandin F1 were observed before and after thetreatment. Results showed that after treatment. the creatinine clearance increased, serum total cholesterol,triglyceride and low density lipoprotein decreased, high density lipoprotein increased, plasma renin activity,angiotensin and urinary thromboxane B2 decreased significantly. The conclusion was that Oenethera bien-nis oil could improve the pathological process of renal diseases, and has benoficial effects on plasma lipiddisorder and glomerular hemodynamics .

Detection of maternal serum thromboxane B2 in different durations of pregnancy and prediction of preeclampsia

This study was aimed to detect maternal serum levels of thromboxane B2(TXB2)in different durations of pregnancy and explore the predictive value of TXB2 for preeclampsia.By employing a prospective and double-blind study method,180 pregnant women with previously normal blood pressures during their progestation were included in the study.Peripheral venous blood samples were obtained during 10+0–14+6(period I),20+0–24+6(period II)and 30+0–34+6(period III)weeks of gestation.Maternal serum levels of TXB2 were measured by enzyme-linked immunoassay.The pathogenetic condition and pregnancy outcomes of these cases were observed.(1)Among the 180 previously normotensive women,ten developed preeclampsia(case group;four severe and six mild preeclampsia).One hundred and seventy remained normal till the end of pregnancy(control group).(2)With development of pregnancy,the levels of maternal serum TXB2 in the 180 cases gradually ascended as seen through the Wilcoxon Signed Ranks Test.There was a statistical significance in maternal TXB2 levels between two different gestational stages(P<0.01).(3)The levels of maternal serum TXB2 were slightly higher in the case group than in the control group during period I of gestation,but the difference was not statistically significant(P>0.05);the levels of TXB2 were significantly higher in the case group than in the control group during periods II and III of gestation(both P<0.05).(3)The best cutoff points of maternal TXB2 were 3750 and 4400 ng/mL during periods II and III of gestation by receiver operator characteristic(ROC)curve;and the sensitivity,specificity,positive predictive value,negative predictive value and odds radio of TXB2 in predicting preeclampsia were 80%,69.5%,13.3%,98.33%,9.11 and 90%,68.82%,13.84%,99.13,19.86,respectively.Higher levels of maternal serum TXB2 were detected a long time before clinical symptoms appeared.The maternal serum TXB2 after 20 weeks of gestation had predictive value,and the index after 30 weeks was superior to that prior to 30 weeks.

缺血性脑卒中后血栓素A2的作用及相关药物研究进展

心脑血管疾病是全球发病率较高的一类疾病,其中脑卒中是全球引起死亡的第二大病因,也是致残的主要原因[1].据美国心脏协会报道,在美国,每19个死亡案例中就有1人死于脑卒中,平均每40秒就有1人患脑卒中[2].在所有脑卒中患者中,高达87％的患者属于缺血性脑卒中.脑卒中系由各种原因所致的局部脑组织区域血液供应障碍,导致脑组织缺血缺氧性病变坏死,进而产生临床上对应的神经功能缺失表现.

Experimental Study on Prevention and Treatment of Rat Passive Hermann Nephritis (PHN) with Ligustrazine

Objective: To explore the effects of ligustrazine on proteinuria, serumcreati-nine, urinary thromboxane A_2(TxA_2), metabolism of prostacyclinI_2(PGI_2)―6-keto-PGF_(1α), and renal pathological changes of SD rats with passive Hermannnephritis (PHN). Methods: The PHN model was induced by intravenous injection of rabbit anti-ratrenal tubular epithelial antigen (Tub―Ag) an-tiserum to SD rats. I. P. administration ofligustrazine to rats was given every 2 d for 1 to 5 weeks. The proteinuria, creatinine, TxA_2 and6-keto-PGF_(1α) were measured by sulfosaticylic acid, picric acid, and direct radioimmunoassayrespectively. The renal pathological changes were observed under light microscope, electronicmicroscope and by direct immunofluorescence staining rabbit and rat IgG. Results: The PHN ratstreated with ligustrazine had significantly less proteinuria, serum creatinine, urinary TxA_2 andpathological changes of kidney, and more urinary 6-keto-PGF_(1α) than those without administrationof ligustrazine. Conclusion: Ligustrazine decreases proteinuria, urinary TxA_2, and renal tissueinjury and increases urinary 6-keto-PGF_(1α). These data indicate that ligustrazine may modulatethe balance of TxA_2 and PG I_2 in rat PHN model and can be used for preventing and treatingmembranous glomerulonephritis.

高凝状态若干临床方面的进展

本文综述高凝状态的病因、发病率、临床表现及其实验室筛选检查,评价其临床意义和实用价值,并详述防治措施。