The plasminogen activating system in the pathogenesis of Alzheimer’s disease

Dementia is a clinical syndrome that affects approximately 47 million people worldwide and is characterized by progressive and irreversible decline of cognitive,behavioral and sesorimotor functions.Alzheimer’s disease(AD)accounts for approximately 60–80%of all cases of dementia,and neuropathologically is characterized by extracellular deposits of insoluble amyloid-β(Aβ)and intracellular aggregates of hyperphosphorylated tau.Significantly,although for a long time it was believed that the extracellular accumulation of Aβwas the culprit of the symptoms observed in these patients,more recent studies have shown that cognitive decline in people suffering this disease is associated with soluble Aβ-induced synaptic dysfunction instead of the formation of insoluble Aβ-containing extracellular plaques.These observations are translationally relevant because soluble Aβ-induced synaptic dysfunction is an early event in AD that precedes neuronal death,and thus is amenable to therapeutic interventions to prevent cognitive decline before the progression to irreversible brain damage.The plasminogen activating(PA)system is an enzymatic cascade that triggers the degradation of fibrin by catalyzing the conversion of plasminogen into plasmin via two serine proteinases:tissue-type plasminogen activator(tPA)and urokinase-type plasminogen activator(uPA).Experimental evidence reported over the last three decades has shown that tPA and uPA play a role in the pathogenesis of AD.However,these studies have focused on the ability of these plasminogen activators to trigger plasmin-induced cleavage of insoluble Aβ-containing extracellular plaques.In contrast,recent evidence indicates that activity-dependent release of uPA from the presynaptic terminal of cerebral cortical neurons protects the synapse from the deleterious effects of soluble Aβvia a mechanism that does not require plasmin generation or the cleavage of Aβfibrils.Below we discuss the role of the PA system in the pathogenesis of AD and the translational relevance of data published to this date.

Diagnostic Value of the Padua Score Combined with Thrombotic Biomarker Tissue Plasminogen Activator Inhibitor-1 (tPAI-1) Detection for the Risk of Deep Vein Thrombosis in Patients with Pulmonary Heart Disease

This study explores the diagnostic value of combining the Padua score with the thrombotic biomarker tissue plasminogen activator inhibitor-1(tPAI-1)for assessing the risk of deep vein thrombosis(DVT)in patients with pulmonary heart disease.These patients often exhibit symptoms similar to venous thrombosis,such as dyspnea and bilateral lower limb swelling,complicating differential diagnosis.The Padua Prediction Score assesses the risk of venous thromboembolism(VTE)in hospitalized patients,while tPAI-1,a key fibrinolytic system inhibitor,indicates a hypercoagulable state.Clinical data from hospitalized patients with cor pulmonale were retrospectively analyzed.ROC curves compared the diagnostic value of the Padua score,tPAI-1 levels,and their combined model for predicting DVT risk.Results showed that tPAI-1 levels were significantly higher in DVT patients compared to non-DVT patients.The Padua score demonstrated a sensitivity of 82.61%and a specificity of 55.26%at a cutoff value of 3.The combined model had a significantly higher AUC than the Padua score alone,indicating better discriminatory ability in diagnosing DVT risk.The combination of the Padua score and tPAI-1 detection significantly improves the accuracy of diagnosing DVT risk in patients with pulmonary heart disease,reducing missed and incorrect diagnoses.This study provides a comprehensive assessment tool for clinicians,enhancing the diagnosis and treatment of patients with cor pulmonale complicated by DVT.Future research should validate these findings in larger samples and explore additional thrombotic biomarkers to optimize the predictive model.

Relationship between matrix metalloproteinase-2 mRNA expression and clinicopathological and urokinase-type plasminogen activator system parameters and prognosis in human gastric cancer

AIM: To investigate the relationship between matrix metalloproteinase-2 (MMP-2) mRNA expression and clinicopathologic and urokinase-type plasminogen activator (uPA) system parameter and prognosis in human gastric cancer. METHODS: Expression of MMP-2 mRNA, uPA, and uPA-R mRNA in tumor tissues and ≥5 cm adjacent normal tissues from 67 cases of gastric cancer was studied using RT-PCR and Northern blot respectively.Survival analyses were done using the Kaplan-Meier method. RESULTS: The expression rates of MMP-2 mRNA,uPA and uPA-R mRNA in tumor tissues (31%,41%,and 51%, respectively) were significantly higher than those in ≥5 cm adjacent tissues (19%, 11%, and 9%; X2=4.59,43.58, and 53.24 respectively, P<0.05,0.0001,and 0.0001, respectively). Expression of MMP-2 mRNA was significantly correlated with lymph node metastasis (metastasis: 61.9%, no metastasis: 39.1%, X2= 7.61, P<0.05),Lauren's classification of diffuse/mixed types:54.2%,intestinal type: 26.3%,X2 = 4.25, P<0.05, expression of uPA and uPA-R mRNA (uPA+: 55.1%, uPA-: 22.2% and uPA-R+: 54.9%, uPA-R-: 18.8%, X2=5.72 and 6.40 respectively, P<0.05).Kaplan-Meier survival analysis of MMP-2 mRNA expression did not show significant difference in all 67 cases, but revealed an association of the expression of MMP-2 mRNA, uPA, and uPA-R mRNA with worse prognosis (P= 0.0083, 0.0160, and 0.0094, respectively). CONCLUSION: MMP-2 may play an important role in the development of invasion and metastasis of gastric cancer.

Urokinase-type plasminogen activator receptor as a predictor of poor outcome in patients with systemic inflammatory response syndrome

BACKGROUND:Urokinase-type plasminogen activator(uPA) and urokinase-type plasminogen activator receptor(uPAR) are known as important factors,which mediate a variety of functions in terms of vascular homeostasis,inflammation and tissue repair.However,their role in systemic inflammatory response syndrome(SIRS) has been less well studied.This study aimed to test the hypothesis that the abnormalities of fibrinolysis and degradation of extracellular matrix mediated by uPA and uPAR are directly related to the patients with SIRS.We therefore analyzed their role and clinicopathological significance in patients with SIRS.METHODS:A case-control study was conducted with 85 patients who were divided into two groups according to the diagnostic criteria of SIRS:SIRS group(n=50) and non-SIRS group(/7=35).The SIRS group was divided into MODS group(n=26) and non-MODS group(n=24) by their severity,and survival group(n=35) and non-survival group(n=15) by their prognosis.Another 30 healthy adults served as normal controls.uPA and uPAR in plasma were detected by commercial enzyme-linked immunosorbent assay(ELISA) kits.RESULTS:The plasma level of uPA was lower in the SIRS group than in the non-SIRS group and controls(P<0.001 and P<0.001).It was lower in sepsis patients and the MODS group than in the non-sepsis patients and the non-MODS patients(all P<0.05).However,there was no difference in uPA level between survivors and non-survivors(P>0.05).The plasma level of uPAR increased in the SIRS group compared with the non-SIRS group and controls(P<0.001 and P<0.001).There was a significant elevation of uPAR in sepsis patients,MODS patients and non-survivors as compared with non-sepsis patients,non-MODS patients and survivors respectively(all P<0.05).Plasma uPAR levels were positively correlated with APACHE Ⅱ score(r=0.575,P<0.001) and SOFA score(r=0.349,P=0.013).AUCs for the prediction of SIRS mortality were 0.67 and 0.51,respectively,for uPA and uPAR.CONCLUSION:uPAR could be a predictor of poor outcome in patients with SIRS.

Tissue-type plasminogen activator is a homeostatic regulator of synaptic function in the central nervous system

Membrane depolarization induces the release of the serine proteinase tissue-type plasminogen activator（t PA） from the presynaptic terminal of cerebral cortical neurons.Once in the synaptic cleft this t PA promotes the exocytosis and subsequent endocytic retrieval of glutamate-containing synaptic vesicles,and regulates the postsynaptic response to the presynaptic release of glutamate.Indeed,t PA has a bidirectional effect on the composition of the postsynaptic density（PSD） that does not require plasmin generation or the presynaptic release of glutamate,but varies according to the baseline level of neuronal activity.Hence,in inactive neurons t PA induces phosphorylation and accumulation in the PSD of the Ca^（2＋）/calmodulin-dependent protein kinase IIα（pCa MKIIα）,followed by pCa MKIIα-induced phosphorylation and synaptic recruitment of Glu R1-containing α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid（AMPA） receptors.In contrast,in active neurons with increased levels of pCa MKIIα in the PSD t PA induces pCa MKIIα and p Glu R1 dephosphorylation and their subsequent removal from the PSD.These effects require active synaptic N-methyl-D-aspartate（NMDA） receptors and cyclin-dependent kinase 5（Cdk5）-induced phosphorylation of the protein phosphatase 1（PP1） at T320.These data indicate that t PA is a homeostatic regulator of the postsynaptic response of cerebral cortical neurons to the presynaptic release of glutamate via bidirectional regulation of the pCa MKIIα/PP1 switch in the PSD.

Tissue plasminogen activator-independent roles of neuroserpin in the central nervous system

A number of studies have confirmed the existence of tissue-type plasminogen activator-independent roles of neuroserpin, a member of the serine protease inhibitor superfamily. In this review article, we aim to clarify this role. These unique roles of neuroserpin are involved in its neuroprotective effect during ischemic brain injury, its regulation of tumorigenesis, and the mediation of emotion and cognition through the inhibition of urokinase-type plasminogen activator and fibrinolysin, modification of Th cells, reducing plaque formation, promoting process growth and intracellular adhesion, and alterina the expression of cadherin and nuclear factor kaooa B.

Clinical Value of ABCB1 and PAI-1 Gene Polymorphisms in Predicting Glucocorticoid-induced Adverse Reactions in Nephrotic Syndrome Patients

Objective Glucocorticoid(GC)-induced adverse reactions(ARs)have been extensively studied due to their potential impact on patients’health.This study aimed to examine the potential correlation between two polymorphisms[adenosine triphosphate-binding cassette B1(ABCB1)C3435T and plasminogen activator inhibitor-1(PAI-1)4G/5G]and various GC-induced ARs in nephrotic syndrome(NS)patients.Methods In this study,513 NS patients who underwent GC treatment were enrolled.Then,the patients were divided into two groups based on ABCB1 C3435T and PAI-14G/5G genotyping,and intergroup comparisons of clinicopathological data and GC-induced ARs were performed.Univariate and multivariate logistic analyses were subsequently conducted to identify potential risk factors for GC-induced ARs,and a nomogram was subsequently established and validated via the area under the ROC curve(AUC),calibration curve and decision curve analysis(DCA).Results We identified ABCB1 C3435T as an independent risk factor for the development of steroid-associated avascular necrosis of the femoral head(SANFH)(OR:2.191,95%CI:1.258–3.813,P=0.006)but not as a risk factor for the occurrence of steroid diabetes mellitus(S-DM).On the other hand,PAI-14G/5G was identified as an independent risk factor for the development of both SANFH(OR:2.198,95%CI:1.267–3.812,P=0.005)and S-DM(OR:2.080,95%CI:1.166–3.711,P=0.013).Notably,no significant correlation was found between the two gene polymorphisms and other GC-induced ARs.In addition,two nomograms were established and validated to demonstrate strong calibration capability and clinical utility.Conclusion Assessing ABCB1 C3435T and PAI-14G/5G before steroid treatment in NS patients could be useful for identifying patients at a high risk of developing SANFH and S-DM.

Platelet-to-neutrophil ratio predicts hemorrhagic transformation and unfavorable outcomes in acute ischemic stroke with intravenous thrombolysis

BACKGROUND Acute ischemic stroke(AIS)retains a notable stance in global disease burden,with thrombolysis via recombinant tissue plasminogen activator(rtPA)serving as a viable management approach,albeit with variable outcomes and the potential for complications like hemorrhagic transformation(HT).The platelet-to-neutrophil ratio(P/NR)has been considered for its potential prognostic value in AIS,yet its capacity to predict outcomes following rtPA administration demands further exploration.AIM To elucidate the prognostic utility of P/NR in predicting HT and clinical outcomes following intravenous rtPA administration in AIS patients.METHODS Data from 418 AIS patients treated with intravenous rtPA at Thammasat University Hospital from January 2018 to June 2021 were retrospectively analyzed.The relationship between P/NR and clinical outcomes[early neurological deterioration(E-ND),HT,delayed ND(D-ND),and 3-mo outcomes]was scrutinized.RESULTS Notable variables,such as age,diabetes,and stroke history,exhibited statistical disparities when comparing patients with and without E-ND,HT,D-ND,and 3-mo outcomes.P/NR prognostication revealed an optimal cutoff of 43.4 with a 60.3%sensitivity and a 52.5%specificity for 90-d outcomes.P/NR prognostic accuracy was statistically significant for 90-d outcomes[area under the curve(AUC)=0.562],D-ND(AUC=0.584),and HT(AUC=0.607).CONCLUSION P/NR demonstrated an association with adverse 3-mo clinical outcomes,HT,and D-ND in AIS patients post-rtPA administration,indicating its potential as a predictive tool for complications and prognoses.This infers that a diminished P/NR may serve as a novel prognostic indicator,assisting clinicians in identifying AIS patients at elevated risk for unfavorable outcomes following rtPA therapy.

Overexpression of hepatic plasminogen activator inhibitor type 1 mRNA in rabbits with fatty liver

INTRODUCTIONPlasminogen activator inhibitor type 1 ( PAI-I ), an approximately Mr 50000 glycoprotein, is the major physiological inhibitor of plasminogen activators. It is not only the priming factor for atherosclerosis and coronary thrombosis[1-3] , but also participates in the genesis of chronic hepatitis and liver fibrosis[4-11] . However, there has been no available report yet about the research of hepatic PAl-1 gene expression in hyperlipidemia and fatty liver. The present study aimed to explore the change of hepatic PAl-1 mRNA and its plasma activity by means of animal model.

Intraclot Recombinant Tissue-type Plasminogen Activator Reduces Perihematomal Edema and Mortality in Patients with Spontaneous Intracerebral Hemorrhage

The study aimed to investigate the impact of intraclot recombinant tissue-type plasminogen activator （rt-PA） on perihematomal edema （PHE） development in patients with intracerebral hemorrhage （ICH） treated with minimally invasive surgery （MIS） and the effects of intraclot rt-PA on the 30-day survival. We reviewed the medical records of ICH patients undergoing MIS between October 2011 and July 2013. A volumetric analysis was done to assess the change in PHE and ICH volumes at pre-MIS （T1）, post-MIS （T2） and day 10-16 （T3） following diagnostic computed tomographic scans （To）. Forty-three patients aged 52.8±11.1 years with （n=30） or without rt-PA （n=13） were enrolled from our institutional ICH database. The median rt-PA dose was 1.5 （1） mg, with a maximum dose of 4.0 mg. The ratio of clot evacuation was significantly increased by intraclot rt-PA as compared with controls （77.9%±20.4% vs. 64%±15%; P=0.046）. From TI to T2, reduction in PHE volume was strongly associ- ated with the percentage of clot evacuation （p=0.34; P=-0.027）. In addition, PHE volume was positively correlated with residual ICH volume at the same day （p ranging from 0.39-0.56, P〈0.01）. There was no correlation between the cumulative dose of rt-PA and early （T2） PHE volume （p=0.24; P=0.12） or de- layed （T3） PHE volume （p=0.19; P=0.16）. The 30-day mortality was zero in this cohort. In the selected cohort of ICH patients treated with MIS, intraclot rt-PA accelerated clot removal and had no effects on PHE formation. MIS aspiration and low dose of rt-PA seemed to be feasible to reduce the 30-day mor- tality in patients with severe ICH. A large, randomized study addressing dose titration and long-term outcome is needed.

INVESTIGATION OF THROMBOMODULIN AND PLASMINOGEN ACTIVATOR INHIBITOR TYPE-I IN PREGNANCY INDUCED HYPERTENSION AND ITS CLINICAL SIGNIFICANCE

Objective. To measure the circulating levels of thrombomodulin (TM) and plasminogen activator inhibitor type- I (PAI- I) in women with pregnancy induced hypertension (PIH). Methods. Blood samples were drawn from 97 pregnant women in their third trimester, grouped as 25 mild PIH,26 moderate PIH,22 severe PIH and 24 normotensive healthy pregnant women for determining levels of TM by ELISA,PAI- I by colorimetric assay methods, and creatinine (Cr) in serum by biochemical method. Results. Circulating levels of TM, PAI- I and TM/Cr ratio increased with increasing severity of PIH. There were no significant differences between mild and normotensive pregnant women. The parameters were significantly changed in the moderate and severe PIH groups. Conclusion. TM and PAI- I may serve as meaningful clinical markers for the assessment of the endothelial damage in PIH, which is very important in evaluating and following the development of PIH.

Urokinase-type plasminogen activator promotes synaptic repair in the ischemic brain

The central nervous system has a very high energy requirement. Accord- ingly, despite representing only 2% of the body＇s mass, the brain uses 20% of the total oxygen consumption. Importantly, because most of this energy is used to maintain synaptic activity, even a mild decrease in its supply to the brain has deleterious implications for synaptic function.

THE INCREASE IN PLASMINOGEN ACTIVATOR INHIBITOR TYPE-1 EXPRESSION BY STIMULATION OF ACTIVATORS FOR PEROXISOME PROLIFERATOR-ACTIVATED RECEPTORS IN HUMAN ENDOTHELIAL CELLS

Objective.To investigate the effect of peroxis ome proliferator-activated recept ors(PPARs )activators on plasminogen activator inhibitor ty pe-1(PAI-1)expression in human umbilical vein e ndothelial cells and the possi-ble mechanism.Methods.Human umbilical vein endothelial ce lls(HUVECs )were obtained from normal fetus,and cul-tured conventionally.Then the HUVECs were exposed to test agents(linolenic acid,linoleic acid,oleic acid,stearic acid and prostaglandin J 2 respectively)in varying concentrations with fresh media.RT -PCR and ELISA were applied to determine the expression of PPARs and PAI-1in HUVECs.Results.PPARα,PPARδand PPARγmRNA were detected by using RT-PCR in HUVECs.Treatment of HUVECs with PPARαand PPARγactivators---linolenic acid,linoleic acid,oleic acid and prostaglandin J 2 respectively,but not with stearic a cid could augment PAI-I mRNA expression and protein secretion in a concentration-dependent manner.However,the mRNA expressions of 3subclasses of PPAR with their activators in HUVECs were not changed compared w ith controls.Conclusion.HUVECs express PPARs.PPARs activators may increase PAI-1expression in ECs,but the underlying mechanism remains uncle ar.Although PPARs expression was not enhanced after stimulated by their activators in ECs,the role of functionally active PPARs in regulating PA I-1expression in ECs needs to be further investigated by using transient gen e transfection assay.

Therapeutic effect of recombinant tissue plasminogen activator on acute cerebral infarction at different times

BACKGROUND:The study aimed to compare the therapeutic effect of recombinant tissue plasminogen activator(rt-PA) on the onset of acute cerebral infarction(ACI) at different time points of the first 6 hours.METHODS:A retrospective analysis was conducted in 74 patients who received rt-PA thrombolysis treatment within 4.5 hours after ACI and another 15 patients who received rt-PA thrombolysis treatment between 4.5-6 hours after ACI.RESULTS:National Institute of Health Stroke Scale(NIHSS) scores were statistically decreased in both groups(P>0.05) at 24 hours and 7 days after ACI.There was no significant difference in modified ranking scores and mortality at 90 days after the treatment between the two groups(P>0.05).CONCLUSIONS:The therapeutic effect and mortality of rt-PA treatment in patients with ACI between 4.5-6 hours after the onset of the disease were similar to those in patients who received rtPA within 4.5 hours after the onset of this disease.Therefore,intravenous thrombolytic therapy for ACI within 4.5-6 hours after ACI was effective and safe.

Recombinant Tissue Plasminogen Activator-conjugated Nanoparticles Effectively Targets Thrombolysis in a Rat Model of Middle Cerebral Artery Occlusion

The efficacy and safety of recombinant tissue plasminogen activator （rtPA） need to be improved due to its low bioavailability and requirement of large dose administration. The purpose of this study was to develop a fibrin-targeted nanoparticle （NP） drug delivery system for thrombosis combination therapy. We conjugated rtPA to poly（ethylene glycol）- poly（ε-caprolactone） （PEG-PCL） nanoparticles （rtPA-NP） and investigated its physicochemical characteristics such as particle size, zeta potential, enzyme activity of conjugated rtPA and its storage stability at 4℃. The thrombolytic activity of rtPA-NP was evaluated in vitro and in vivo as well as the half-life of rtPA-NP, the properties to fibrin targeting and its influences on systemic hemostasis in vivo. The results showed that rtPA-NP equivalent to 10% of a typical dose of rtPA could dissolve fibrin clots and were demonstrated to have a neuroprotective effect after focal cerebral ischemia as evidenced by decreased infarct volume and improved neurological deficit （P〈0.001）. RtPA-NP did not influence the in vivo hemostasis or coagulation system. The half-life of conjugated rtPA was shown to be approximately 18 times longer than that of free rtPA. These experiments suggested that rtPA-conjugated PEG-PCL nanoparticles might be a promising fibrin-targeted delivery system for a combination treatment of thrombosis.

UROKINASE-TYPE PLASMINOGEN ACTIVATOR,ITS RECEPTOR AND INHIBITOR EXPRESSION IN HEPATOCELLULAR CARCINOMA RELATION TO CANCER INVASIVENESS AND PROGNOSIS

Objective: To study the relevance of uPA, uPAR and PAI 1 to hepatocellular carcinoma (HCC) Methods: The expression at protein level of uPA, uPAR and PAI 1 was determined in 48 cases of HCC and 12 cases of benign tumors of liver (as control) by immunohistochemistry Results: When compared to cancer adjacent liver tissue and the control, positive rate of immune staining for uPA, uPAR and PAI 1 on cell membrane were significantly higher in HCC cells ( P <0 05) Positive staining of uPA and uPAR was seen in 16 of 22 and 19 of 22 cases of HCC with invasion, respectively ( P <0 01 and P <0 001) In 8 of 8 cases with cancer embolus, and in 6 of 6 cases with lymph node metastasis was the expression of positive uPAR Compared with 2 of 17 cases without recurrence, uPAR was positive in 15 of 17 recurrent cases ( P <0 01) In 36 cases who survived, 17 was positive uPAR and 15 positive PAI 1, while in 12 cases who died 2 years after surgery, 12 were positive for uPAR and 9 positive PAI 1, respectively ( P <0 01 and P <0 05) In 15 positive cases for all three parameters, 11 had cancer invasion and 7 died within 2 years, while in negative cases, 2 had invasion and none died within 2 years ( P <0 05) Conclusion: Expression of uPA, uPAR and PAI 1 is increased in HCC, uPA and uPAR may contribute significantly to HCC invasion and metastasis uPAR and PAI 1 are associated with poor prognosis of HCC

Gene expression changes of urokinase plasminogen activator and urokinase receptor in rat testes at postnatal stages

Aim： To investigate the gene expression changes of urokinase plasminogen activator （uPA）/urokinase receptor （uPAR） in rat testes at postnatal stages and explore the effects of uPA/uPAR system on the rat spermatogenesis. Methods： The mRNAs of uPA and uPAR in rat testes were measured by using real-time quantitative polymerase chain reaction （PCR） at postnatal days 0, 5, 10, 15, 21, 28, 35, 42, 49 and 56, respectively. Results： The tendencies of uPA and uPAR mRNA expression were similar at most postnatal stages except for Do. The expression of uPAR mRNA in rats testes was relatively higher than that of uPA at postnatal Do, and both were decreased until D21, increased obviously at postnatal D28, reached a peak at postnatal D35, then declined sharply at postnatal D42 and retained at a low level afterwards. Conclusion： The uPA/uPAR system may be strongly linked to spermiation and spermatogenesis via regulating germ cell migration and proliferation, as well as promoting the spermiation and detached residual bodies from the mature spermatids.

Roles of tissue plasminogen activator and its inhibitor in proliferative diabetic retinopathy

AIMTo investigate the role of tissue plasminogen activator (t-PA) and plasminogen activator inhibitor (PAI) in proliferative diabetic retinopathy (PDR) and to discuss the correlations among t-PA, PAI and vascular endothelial growth factor (VEGF) expressions.

Studies on the Relationship between Urokinase Plasminogen Activator(uPA)and Human Sperm Motility

To clarify the role of urokinase plasminogen activator(uPA) in the mechanisms of regulating sperm motility and the ability of fertilizing, we investigated the quantities and activities of uPA in human seminal Plasma and on the membrane of spermatozoa.Semens were harvested from 22 infertile patients with asthenospermia and 20 healthy fertile men according to WHO standards. To quantify the membrane-bound uPA in the samples, polyclonal antibodies against human urokinase were employed by means of a sandwich ELISA. The uPA activities in seminal plasma and on the surface of spermatozoa were determined using Agarose-Fibrine-Plate method and the experiment of immunological identification with polyclonal antibodies against urokinase. In lysates of spermatozoa, significantly lower levels of uPA(23. 1±7.35 mu/106 cells ) and uPA activity (5.13±3.85 mu/106 cells) were found in patient group as compared to healthy fertile men exhibiting normospermia (29. 89±9. 40 mu/105 cells and 10. 17±6. 18 mu/106 cells). In seminal plasma, uPA activity in patient group (2134±1581. 3 IU/L)was also found significantly lower than that of normal group (3365±1859. 5 IU/L). Positive correlations were observed between sperm motility and uPA quantities (r=0. 48, P＜0. 005), as well as with uPA activities (r= 0. 45,P＜0. 005).Thus, it is inferred that membrane associated uPA on human spermatozoa may be related directly to sperm motility and fertility.

Activity of Ginkgo biloba Extract and Quercetin on Thrombomodulin Expression and Tissue-type Plasminogen Activator Secretion by Human Umbilical Vein Endothelial Cells

Objective In order to investigate the pharmacological properties of Ginkgo biloba extract （GBE） on improving blood circulation, the regulating action of GBE and quercetin （a main flavonoid ingredient in GBE） on thrombomodulin （TM） expression and tissue-type plasminogen activator （t-PA） secretion was studied. Methods Using flow cytometer and gel image system respectively, we evaluated the TM expression and the t-PA secretion by human umbilical vein endothelial cells （HUVECs） in vitro. Results The increase of TM expression on HUVECs surface was induced by GBE rather than quercetin in a dose- and time-dependent manner. Both GBE and quercetin increased the t-PA release significantly. Conclusion The effect of GBE on improving blood circulation may be partly attributed to its promoting TM expression and t-PA secretion by endothelial ceils, and quercetin participated in the effect of GBE on t-PA secretion. However, the action of GBE on increasing TM expression needs further study.