In order to further investigate the effect of annexin II (Ann-II) on tissue plasminogen activator (t-PA)-dependent plasminogen (PLG) activation and its interactive mechanism, recombinant native Ann-II bound t-PA, PLG and plasmin with high affinity was examined. The flow cytometric assay showed that the ann-II expression rate was higher in the human umbilical vein endothelial cell (HUVEC) (87.65%) than in the HL-60 cells as controls (35.79%). Two irrelevant proteins, bovine serum albumin (BSA) and equine IgG (EIG) had no effect on the production of plasmin. Ann-II-mediated enhancement of t-PA-dependent PLG activation was inhibited by epsilon-aminocaproic acid or by pretreatment of Ann-II with carboxypeptidase B with the inhibitive rate being 77.8% and 77.0%, respectively. It was revealed that the effect of Ann-II on PLG activation was specific for t-PA. Urokinase didn't bind to Ann-II, demonstrating the role of receptor-related lysine residues on activation of PLG, showing that the Ann-II-PLG interaction was dependent upon carboxyl-terminal lysine residues. These findings suggest that annexin II-mediated co-assembly of t-PA and PLG may promote plasmin generation and play a key role in modulating fibrinolysis on the endothelial surface.
Annexin A2 ; pharmacology ; Cells, Cultured ; Endothelium, Vascular ; cytology ; metabolism ; Fibrinolysis ; Humans ; Plasminogen ; metabolism ; Recombinant Proteins ; pharmacology ; Tissue Plasminogen Activator ; metabolism ; Umbilical Veins ; cytology

In order to further investigate the effect of annexin II (Ann-II) on tissue plasminogen activator (t-PA)-dependent plasminogen (PLG) activation and its interactive mechanism, recombinant native Ann-II bound t-PA, PLG and plasmin with high affinity was examined. The flow cytometric assay showed that the ann-II expression rate was higher in the human umbilical vein endothelial cell (HUVEC) (87.65%) than in the HL-60 cells as controls (35.79%). Two irrelevant proteins, bovine serum albumin (BSA) and equine IgG (EIG) had no effect on the production of plasmin. Ann-II-mediated enhancement of t-PA-dependent PLG activation was inhibited by epsilon-aminocaproic acid or by pretreatment of Ann-II with carboxypeptidase B with the inhibitive rate being 77.8% and 77.0%, respectively. It was revealed that the effect of Ann-II on PLG activation was specific for t-PA. Urokinase didn't bind to Ann-II, demonstrating the role of receptor-related lysine residues on activation of PLG, showing that the Ann-II-PLG interaction was dependent upon carboxyl-terminal lysine residues. These findings suggest that annexin II-mediated co-assembly of t-PA and PLG may promote plasmin generation and play a key role in modulating fibrinolysis on the endothelial surface.
Annexin A2/*pharmacology ; Cells, Cultured ; Endothelium, Vascular/cytology ; Endothelium, Vascular/*metabolism ; Fibrinolysis ; Plasminogen/*metabolism ; Recombinant Proteins/pharmacology ; Tissue Plasminogen Activator/*metabolism ; Umbilical Veins/cytology

OBJECTIVE: To investigate the antithrombotic effects of recombinant hirudin and its mechanism. METHODS: Sixty male Kunming mice were randomly divided into 6 group (=10):control group, model group, aspirin (25 mg/kg) group, recombinant hirudinlow, middle and high dose (0.05, 0.1, 0.2 mg/kg) groups.Except mice in control group, 2.5 mg/kg carrageenan was injected intraperitoneallyto mice in the other groups to produce thrombosis on the mice tail. The mice in aspirin group were administrated intraperitoneally 25 mg/kg aspirin, the mice in recombinant hirudinlow, middle and high dose groups were administrated intraperitoneally 0.05, 0.1, 0.2 mg/kg combinanthirudin, the mice in control group and model group were administrated intraperitoneallynormal saline at the same volume respectively at 24 h, 0.5 h before injecting carrageenan and 24 h after injecting carrageenan. The black tail length of mice and the incidence of black tail were observed at 48h after injection of carrageenan; prothrombin time (PT), activated partial thromboplastin time (APTT), tissue plasminogen activator (t-PA), type-1 plasminogen activator inhibitor (PAI-1), 6-keto-PGF1α, and thromboxane B2 (TXB2) level in mice plasma were determined. RESULTS: As compared with control group, the mice in model group presented tail thrombosis; PT level in plasma was significantly shortened (<0.01), PAI-1 and TXB2levels in plasma were significantly increased (<0.01), while the t-PA and 6-keto-PGF1α levels in plasma in model group were significantly decreased (<0.01). As compared with model group, the thrombus length in the tail was significantly shortened (<0.05, <0.01), PT level was obviously prolonged (<0.01), and the plasma levels of PAI-1 and TXB2 were significantly decreased (<0.01), while the plasma levels of t-PA and 6-keto-PGF1α were significantly increased (<0.01)in the mice of recombinant hirudin low dose, middle dose, high dose groups and aspirin group. As compared with aspirin group, the thrombus length in the tail was significantly increased (<0.05), PT level was obviously shortened (<0.01), and the plasma levels of PAI-1 and TXB2 were significantly increased (<0.01)in the mice of recombinant hirudin low dose group; the plasma level of 6-keto-PGF1α was significantly decreased (<0.01, <0.05) in the mice of recombinant hirudin low dose and middle dose groups; the plasma levels of PAI-1 and TXB2 were significantly increased (<0.01, <0.05)in the mice of recombinant hirudin middle dose group. CONCLUSIONS The recombinant hirudin can fight against thrombosis, its antithrombotic mechanisms may be related to its influence on the exogenous coagulation system and the promotion of fibrinolysis function.
Animals ; Blood Coagulation ; Fibrinolytic Agents ; Hirudins ; pharmacology ; Male ; Mice ; Recombinant Proteins ; Thromboxane B2 ; Tissue Plasminogen Activator

AIMTo investigate the antithrombotic effects of morpholine and piperazine ring derivatives and their mechanisms.

METHODSIn isolated rat aorta-precontracted with norepinephrine (NE), the vasodilatory effects of compounds with novel structure were investigated. Mice was given kappa-carrageenin i.p. and kept at the temperature of (20-21) degree C.

RESULTS AND CONCLUSIONActive candidate compounds including MOPMC, 2FBMPC, MPTMBC, DMHPPP and PPVP were shown to antagonize thrombosis at the dose of 1 mg.kg-1 through activating the endothelial target for acetylcholine; while the contrasting compounds MAPC, 4C3FBMOC, mTBMPC, MONVP and MPNVP showed no significant effect on the tension of isolated aorta strips or significant antithrombotic effects at the same dose. The antithrombotic mechanism of novel compounds is not relevant to hemostatic systems or functions of platelet aggregation directly, but they can promote endothelial cells to release tissue-type plasminogen activator (t-PA) and inhibit the activity of plasminogen activator inhibitor-1 (PAI-1).

Animals ; Aorta, Thoracic ; Endothelium, Vascular ; drug effects ; metabolism ; Female ; Fibrinolytic Agents ; pharmacology ; Male ; Mice ; Morpholines ; pharmacology ; Piperazines ; pharmacology ; Plasminogen Activator Inhibitor 1 ; metabolism ; Platelet Aggregation ; drug effects ; Rats ; Rats, Wistar ; Tissue Plasminogen Activator ; metabolism ; Vasodilator Agents ; pharmacology

OBJECTIVETo study the protective impact of tea polyphenols (TP) on the injury of fibrinolytic functions induced by high-methionine dietary in rats.

METHODS50 male Wistar rats were divided by stratified based on body weight into 5 groups with 10 in each group: namely control group, model group, low-dose TP group, medium-dose TP group and high-dose TP group. The rats in model group and TP groups were fed with 3% methionine dietary, control group rats with routine diet. In addition, rats in low-dose, medium-dose and high-dose TP groups were treated with TP at 50, 100 and 200 mg/kg dosage respectively by gavages every day, control group and model group rats were given with same amount distilled water. The animals were sacrificed after 8 weeks. The levels of tissue-type plasminogen activator (t-PA) and type-1 plasminogen activator inhibitor (PAI-1) in plasma were determined by ELISA assays, mRNA levels of t-PA and PAI-1 in aortic arch were detected by RT-PCR, t-PA and PAI-1 expression in aortic arch were detected by immunohistochemistry strept-avidin-biotin complex (SABC).

RESULTSAfter experiment, the t-PA expression of aortic arch in control group, model group, low-dose TP group, medium-dose TP group and high-dose TP group were 133.03 ± 10.14, 95.46 ± 11.08, 111.97 ± 11.91, 130.23 ± 10.80, 139.39 ± 9.41 (F = 14.15, P < 0.01), respectively, and the PAI-1 expression were 90.91 ± 8.67, 166.76 ± 12.18, 139.63 ± 12.71, 134.66 ± 13.19, 109.49 ± 10.82 (F = 31.44, P < 0.01). The t-PA concentration of plasma were (10.69 ± 1.26), (6.13 ± 0.92), (8.56 ± 1.19), (9.69 ± 0.92), (11.97 ± 1.08) ng/ml, respectively (F = 41.98, P < 0.01), and the PAI-1 concentration of plasma were (6.31 ± 0.81), (16.98 ± 1.27), (11.39 ± 0.82), (8.46 ± 0.67), (8.08 ± 0.91) ng/ml, respectively (F = 207.74, P < 0.01). The mRNA levels of t-PA in aortic arch were 1.12 ± 0.02, 0.75 ± 0.14, 1.01 ± 0.09, 0.95 ± 0.08, 1.05 ± 0.13 (F = 5.77, P < 0.05), and the mRNA levels of PAI-1 in aortic arch were 1.25 ± 0.11, 1.74 ± 0.06, 1.23 ± 0.05, 1.09 ± 0.14, 1.23 ± 0.04 (F = 23.56, P < 0.01).

CONCLUSIONThe results indicate that TP seems to have regulatory function on transcription and protein levels of t-PA and PAI-1, in addition to maintaining the balance between PAI-1 and t-PA and healing the injury of fibrinolytic functions in rats induced by high-methionine dietary.

Animals ; Diet ; Fibrinolysis ; drug effects ; Male ; Methionine ; adverse effects ; Plasminogen Activator Inhibitor 1 ; blood ; Polyphenols ; pharmacology ; Rats ; Rats, Wistar ; Tea ; chemistry ; Tissue Plasminogen Activator ; blood

AIMTo investigate the influences of testosterone with varied concentrations on the functions of HUVEC.

METHODSHuman umbilical vein endothelial cells within 2-3 passages were cultured with testosterone (3 x 10(-10) to 3 x 10(-8), 3 x 10(-6), 3 x 10(-5) mol/ L), and the control confluent cells were cultured in the same medium without steroid. MTT experiment was repeated for 7 days to investigate each groups' cell proliferation. The values of NO were tested as recommended. The tPA and PAI-1 antigen levels were assayed with ELISA Kits.

RESULTSTestosterone at physiologic or lower concentrations (3 x 10(-10) to 3 x 10(-8) mol/L ) had no adverse effect on A490 and NO level, meanwhile, stimulated the secretion of tPA (P < 0.01). However, tPA levels markedly reduced at larger dose (3 x 10(-6) to 3 x 10(-5) mol/L). On the other hand, PAI-1 antigen levels decreased significantly at the testosterone concentrations ranging from 3 x 10(-10) to 3 x 10(-5) mol/L (P < 0.05).

CONCLUSIONTestosterone at physiologically relevant concentrations affectively decreased PAI-1, while increased tPA levels, which suggested that testosterone might have beneficial effects on the Human umbilical vein endothelial cells and cardiovascular system to prevent atherosclerosis.

Cells, Cultured ; Human Umbilical Vein Endothelial Cells ; drug effects ; metabolism ; Humans ; Nitric Oxide ; metabolism ; Plasminogen Activator Inhibitor 1 ; metabolism ; Testosterone ; pharmacology ; Tissue Plasminogen Activator ; metabolism

OBJECTIVETo study the effect of anti-progression activity of edible plants using urokinase as the biomarker.

METHODSBased on the assay of urokinase activity with peptide of Glu-Gly-Arg as the reaction substrate, extract of 25 fruits and 37 vegetables and water extract of tea were reacted against urokinase activity after Spectrozyme UK [carbobenzyl-1-gamma-Glu(alpha-t-BuO)-Gly-Arg-rho-nitroanilide. 2C2H5OH] was added and the residual urokinase activity was measured by the microplate photometer.

RESULTSAbout half of the fruit and vegetable samples showed urokinase inhibitory activity (UIA) at 20% or more and among them lemon, kiwi-fruit, peas, spinach and pumpkin showed effects over 80%, while garlic, radish, Japanese butterbur, garland chrysanthemum, celery, plum, pineapple and grape ranged between 50% and 79%. Average UIA of 51 kinds of tea was 83.2% and among them 28 kinds showed UIA over 90% and other 20 kinds of tea ranged from 70% to 89%. Green tea showed inhibitory effects on urokinase activity more powerful than black tea and Oolong tea. On the other hand, vegetable showed various UIA with different ways of processing. Comparing the effects of various solvents, garlic extracted with methanol, spinach with ethyl acetate, and pumpkin and radish with water showed highest UIA.

CONCLUSIONPopular fruits, vegetables and tea in daily life could inhibit urokinase activity and may be helpful in the prevention of malignant tumor formation.

Fruit ; chemistry ; Plant Extracts ; pharmacology ; Plants, Edible ; chemistry ; Tea ; chemistry ; Urokinase-Type Plasminogen Activator ; antagonists & inhibitors ; metabolism ; pharmacology ; Vegetables ; chemistry

AIMTo investigate the effect of different peroxisome proliferator-activated receptors (PPARs) activators on plasminogen activator inhibitor-1 in HepG-2 cell line and explore the effect of PPARs on PAL-1 gene expression.

METHODSStearic acid, oleic acid, linoleic acid, fenofibrate, pioglitazone were used in the treatment of HepG-2 cell culture. The level of PAI-1 and PPARs mRNA was measured by reverse transcription-polymerase chain reaction (RT-PCR) and the level of PAI-1 activity and PPARs protein was determined by colorimetric assay and western blotting respectively.

RESULTSThe mRNA and activity of PAI-1 significantly increased in the groups of oleic acid and linoleic acid compared with the control, but decreased in the group of fenofibrate. There were no significant changes in both groups of stearic acid and pioglitazone. The alterations in the level of PPARs mRNA and protein were not detected in all the treated groups compared with the control.

CONCLUSIONPeroxisome proliferator-activated receptors activators play important roles in the PAI-1 gene expression and regulation. It is likely mediated by the activation of PPARalpha, but there might be other mechanisms.

Fenofibrate ; pharmacology ; Hep G2 Cells ; Humans ; Linoleic Acid ; pharmacology ; Oleic Acid ; pharmacology ; Peroxisome Proliferator-Activated Receptors ; agonists ; metabolism ; Plasminogen Activator Inhibitor 1 ; genetics ; metabolism ; RNA, Messenger ; genetics

OBJECTIVETo investigate the effect of cilazapril on endothelial cell function and fibrinolysis system in the canine atrial fibrillation (AF) models.

METHODSAll canines were divided into three groups: (1) Control group, without atrial pacing; (2) Atrial pacing group, in which atrial fibrillation was established by rapid atrial pacing at 400 bpm for 6 weeks; (3) Atrial pacing together with cilazapril group, in which cilazapril was given before and after atrial pacing. Nitric oxide (NO) of atrial endocardium was measured with NO-specific microelectrode. The expression of plasminogen activator inhibitor-1 (PAI-1) and tissue-type plasminogen activator (tPA) protein in atrium was determined by Western Blot analysis and immunohistochemical staining. Plasma levels of von Willebrand Factor (vWF), PAI-1 and tPA were analyzed by enzyme-linked immunoadsorbent assay.

RESULTSNO production from atrial endocardium was significantly increased in atrial pacing together with cilazapril group than atrial pacing group [(42.6 +/- 9.9) nmol/L vs (23.4 +/- 5.8) nmol/L, P < 0.05], whereas the plasma levels of vWF were decreased [(75.4 +/- 12.8)% vs (125.9 +/- 20.6)%, P < 0.05]. Compared to controls, the expression of atrium tPA protein in atrial pacing together with cilazapril group was significantly upregulated (4052 +/- 857 vs 1936 +/- 421, P < 0.05) and PAI-1 protein was downregulated (2487 +/- 542 vs 3164 +/- 827, P < 0.05). Cilazapril also significantly increased tPA antigen and decreased PAI-1 antigen in plasma.

CONCLUSIONCilazapril can favorably improve endothelial function and resume the balance of fibrinolysis system in AF, which might be of beneficial to hypercoagulated state in AF.

Angiotensin-Converting Enzyme Inhibitors ; pharmacology ; Animals ; Atrial Fibrillation ; blood ; drug therapy ; physiopathology ; Cilazapril ; pharmacology ; Disease Models, Animal ; Dogs ; Endothelial Cells ; drug effects ; physiology ; Female ; Fibrinolysis ; drug effects ; Immunohistochemistry ; Male ; Plasminogen Activator Inhibitor 1 ; analysis ; Tissue Plasminogen Activator ; analysis

BACKGROUNDCigarette smoking has an influence on both arterial-type and venous-type thrombosis. However, little is known about the direct effect of cigarette smoke extract (CSE) on fibrinolytic activity of human umbilical vein endothelial cells (HUVECs). Most recently, simvastatin has been marked in its effect on endothelial cells protection and anticoagulation. In this study, the effect of CSE on the expression of tissue-type plasminogen activator (t-PA) and plasminogen activator inhibitor-1 (PAI-1) in HUVECs was addressed. The role of simvastatin in CSE-induced fibrinolytic activity changes was investigated as well.

METHODSThe fourth to fifth generation of HUVECs were incubated respectively with 0, 5%, 10% and 20% CSE for 6 hours or exposed to 5% CSE for 0, 4, 6, 8, 12, 24 hours to determine the expression changes of t-PA and PAI-1 protein. Meanwhile, cells were also accordingly exposed either to 5% CSE alone or simvastatin pre-treated and 5% CSE for 24 hours to assess the role of simvastatin in CSE-induced t-PA and PAI-1 protein and mRNA expression in HUVECs. RT-PCR and ELISA techniques were used for detecting the t-PA or PAI-1 mRNA and protein.

RESULTSAfter 6-hour exposure to CSE, the expression levels of t-PA protein in 10% and 20% CSE-treated groups reduced significantly ((0.0365 +/- 0.0083) ng/ml, (0.0255 +/- 0.0087) ng/ml) when compared with that of control group ((0.0660 +/- 0.0120) ng/ml) (P < 0.05). In contrast, the levels of PAI-1 protein in 5%, 10% and 20% CSE-treated groups increased remarkably ((13.3225 +/- 0.5680) ng/ml, (14.2675 +/- 1.5380) ng/ml, (14.4292 +/- 1.6230) ng/ml) when compared with that of control group ((8.5193 +/- 0.7537) ng/ml) (P < 0.05). After stimulation with 5% CSE for 0, 4, 6, 8, 12, 24 hours, the levels of PAI-1 protein increased over time and reached the peak at 24 hours ((14.6400 +/- 1.0651) ng/ml), which was significantly higher than that of control group ((12.0656 +/- 0.6148) ng/ml) (P < 0.05). Additionally, CSE could up-regulate PAI-1 expression at both the mRNA and the protein levels. The levels of PAI-1 mRNA and protein increased significantly in 5% CSE-treated group ((8.8030 +/- 0.4745) ng/ml, (1.8155 +/- 0.0412) ng/ml) compared with those of control groups ((5.0588 +/- 0.2315) ng/ml, (1.3030 +/- 0.0647) ng/ml) (P < 0.01), and decreased after 2-hour simvastatin pre-treatment ((5.4875 +/- 0.3166) ng/ml, (1.3975 +/- 0.0297) ng/ml) (P < 0.01). No significant difference was found at the levels of t-PA protein and mRNA (P > 0.05).

CONCLUSIONSCSE inhibits the fibrinolytic activity of HUVECs in vitro. Simvastatin plays a protective role in CSE-induced fibrinolytic malfunction.

Cells, Cultured ; Endothelial Cells ; metabolism ; Fibrinolysis ; drug effects ; Humans ; Hydroxymethylglutaryl-CoA Reductase Inhibitors ; pharmacology ; Plasminogen Activator Inhibitor 1 ; analysis ; biosynthesis ; genetics ; Simvastatin ; pharmacology ; Smoke ; adverse effects ; Tissue Plasminogen Activator ; analysis ; biosynthesis ; genetics ; Tobacco ; adverse effects ; Umbilical Veins ; cytology