Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “PLASMINOGEN”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 901 records · Page 50Linked to original sources
PubMed1999

Homologous plasminogen N-terminal and plasminogen-related gene A and B peptides. Characterization of cDNAs and recombinant fusion proteins.

The cDNA corresponding to exons 2-4 of the processed human plasminogen (Pgn) gene, encoding the N-terminal peptide domain (NTP), has been cloned, expressed in Escherichia coli as a recombinant protein (r-NTP) containing a hexahistidine tag, and refolded to the native structure that contains two internal cystine bridges. RNA expression of the two Pgn-related genes, PRG A and PRG B, that potentially encode 9-kDa polypeptides having extensive similarity to the NTP has been investigated. Using RNA-based PCR with liver RNA as template, we demonstrate that PRG A encodes a detectable mRNA species. PRG A and PRG B have been found to be transcribed in the liver and yield virtually identical mRNAs. Neither of the PRGs are expressed in a variety of other normal tissues, as determined by Northern blot analysis. Factor-Xa digestion of the tagged r-NTP yields cleavage products which indicates that the expressed r-NTP domain of Pgn is endowed with a flexible conformation. Recombinant PRG B protein (r-PRG B) fused to a hexahistidine tag was purified and analyzed for structural integrity. Preliminary 1H-NMR spectroscopic data for r-NTP and r-PRG B indicate relatively fast amide 1H-2H exchange in 2H2O and close conformational characteristics for the two homologous polypeptides. Far ultraviolet-CD spectra for r-NTP and r-PRG B at pH 7.0 indicate similar defined secondary structure content for both domains, with 13-17% alpha-helix and 24-27% antiparallel beta-sheet. The fact that two transcriptionally active genes encode almost identical polypeptides supports the hypothesis that the Pgn NTP, together with the putative polypeptides encoded by the PRGs, may serve an important function, such as controlling the conformation of Pgn and thus its susceptibility to tissue activators.

Amino Acid Sequence↗
PubMed1996

Interactions between staphylokinase, plasmin(ogen), and fibrin. Staphylokinase discriminates between free plasminogen and plasminogen bound to partially degraded fibrin.

Staphylokinase (STA), a protein of bacterial origin, induces highly fibrin-specific thrombolysis both in human plasma in vitro and in pilot clinical trials. Using fluorescence microscopy, we investigated the spatial distribution of fluorescein isothiocyanate (FITC)-labeled STA during lysis of a plasma clot and its binding to purified fibrin clots in the presence or in the absence of plasmin(ogen). STA highly accumulated in a thin superficial layer of the lysing plasma clot following the distribution of plasminogen (Pg) during lysis. Experiments with purified fibrin clots revealed that STA binds to Pg bound to partially degraded fibrin but not to Pg bound to intact fibrin. Binding of FITC-labeled STA to various forms of plasmin(ogen) in a buffer solution was studied by measuring fluorescence anisotropy. The binding constant for Glu-Pg was estimated as 7.4 microM and for Lys-Pg as 0.28 microM; for active-site blocked plasmin the binding constant was less than 0.05 microM. The much lower affinity of STA for Glu-Pg compared with that for active site-blocked plasmin was mainly due to a lower association rate constant, as assessed by real time biospecific interaction analysis. Gel filtration of a mixture of STA with a molar excess of Glu-Pg demonstrated that STA migrated as an unbound 18-kDa protein when activation of Pg into plasmin was precluded by inhibitors of plasmin. When gel-filtered under the same conditions with plasmin, STA migrated in complex with plasmin with an apparent molecular mass of 100 kDa. Confocal fluorescence microscopy finally demonstrated that when FITC-labeled STA was added to plasma before clotting, it did not bind to fibrin fibers during the first minutes (lag phase), although Pg bound to the fibers moderately. Then, both Pg and STA started to accumulate on the fibers progressively, followed by complete lysis of the clot. In conclusion, our results imply that, when STA is added to plasma, only a small percentage associates with Pg. In contrast, STA binds strongly to plasmin and to Pg, which is bound to partially degraded fibrin. These findings add a new mechanism to the known explanations for the inefficient Pg activation by STA in plasma and specify the mechanism for fibrin-dependent activation of Pg.

Chromatography, Gel↗
PubMed2005

RNA interference-directed knockdown of urokinase plasminogen activator and urokinase plasminogen activator receptor inhibits prostate cancer cell invasion, survival, and tumorigenicity in vivo.

The invasive ability of tumor cells plays a key role in prostate cancer metastasis and is a major cause of treatment failure. Urokinase plasminogen activator-(uPA) and its receptor (uPAR)-mediated signaling have been implicated in tumor cell invasion, survival, and metastasis in a variety of cancers. This study was undertaken to investigate the biological roles of uPA and uPAR in prostate cancer cell invasion and survival, and the potential of uPA and uPAR as targets for prostate cancer therapy. uPA and uPAR expression correlates with the metastatic potential of prostate cancer cells. Thus, therapies designed to inhibit uPA and uPAR expression would be beneficial. LNCaP, DU145, and PC3 are prostate cancer cell lines with low, moderate, and high metastatic potential, respectively, as demonstrated by their capacity to invade the extracellular matrix. In this study we utilized small hairpin RNAs (shRNAs), also referred to as small interfering RNAs, to target human uPA and uPAR. These small interfering RNA constructs significantly inhibited uPA and uPAR expression at both the mRNA and protein levels in the highly metastatic prostate cancer cell line PC3. Our data demonstrated that uPA-uPAR knockdown in PC3 cells resulted in a dramatic reduction of tumor cell invasion as indicated by a Matrigel invasion assay. Furthermore, simultaneous silencing of the genes for uPA and uPAR using a single plasmid construct expressing shRNAs for both uPA and uPAR significantly reduced cell viability and ultimately resulted in the induction of apoptotic cell death. RNA interference for uPA and uPAR also abrogated uPA-uPAR signaling to downstream target molecules such as ERK1/2 and Stat 3. In addition, our results demonstrated that intratumoral injection with the plasmid construct expressing shRNAs for uPA and uPAR almost completely inhibited established tumor growth and survival in an orthotopic mouse prostate cancer model. These findings uncovered evidence of a complex signaling network operating downstream of uPA-uPAR that actively advances tumor cell invasion, proliferation, and survival of prostate cancer cells. Thus, RNA interference-directed targeting of uPA and uPAR is a convenient and novel tool for studying the biological role of the uPA-uPAR system and raises the potential of its application for prostate cancer therapy.

Animals↗
PubMed2006

A novel function of plasminogen activator inhibitor-1 in modulation of the AKT pathway in wild-type and plasminogen activator inhibitor-1-deficient endothelial cells.

Cell proliferation, an event associated with angiogenesis, involves coordinated activities of a number of proteins. The role of plasminogen activator inhibitor-1 (PAI-1) in angiogenesis remains controversial. Utilizing proliferating PAI-1-/- endothelial cells (EC), the impact of a host PAI-1 deficiency on Akt activation was evaluated. Hyperactivation of Akt(Ser(P)473) was observed in PAI-1-/- EC, and this was probably due to enhanced inactivation of tumor suppressor PTEN, thus rendering the cells resistant to apoptotic signals. Higher levels of inactivated caspase-9 in PAI-1-/- EC led to lower levels of procaspase-3 and cleaved caspase-3, thereby promoting survival. These effects were reversed when recombinant PAI-1 was added to PAI-1-/- EC. Additional studies demonstrated that regulation of proliferation is dependent on its interaction with low density lipoprotein receptor-related protein. Thus, PAI-1 is a negative regulator of cell growth, exerting its effect on the phosphatidylinositol 3-kinase/Akt pathway and allowing controlled cell proliferation.

Animals↗
PubMed1988

Plasminogen hemizygosity. Detection of a silent allele in 7 members of a family by determination of plasminogen phenotypes, antigenic levels, and functional activity.

The accumulation of the homozygous plasminogen (PLG) variant A3 in 4 siblings of a family led to the detection of 5 cases of apparent inverse homozygosity of PLG phenotypes which seemed to exclude paternity. Determination of 22 blood group markers and HLA typing, but under exclusion of PLG phenotypes, confirmed paternity in all cases (biostatistical probability of paternity greater than 99.9985%). Comparing the results of 'Western blots' with functional-caseinolytic phenotyping, the existence of inactive plasmin, as described earlier, could be excluded. Besides inverse homozygosity the assumption of a silent allele was confirmed by reduction of PLG antigenic levels and functional activities to approximately 50% of normal range. The PLG phenotype A in 1 individual with anamnestic thrombosis, reduced values of PLG antigen, and reduced functional activity, although in accordance with Mendelian inheritance, was also considered as indicative for PLG hemizygosity.

Alleles↗
PubMedDate not supplied

Administration of exogenous tissue plasminogen activator reduces oedema in mice lacking the tissue plasminogen activator gene.

It has recently become apparent that tissue plasminogen activator (tPA) modulates inflammation in diseases such as rheumatoid arthritis (RA) and acute respiratory distress syndrome (ARDS). We have shown previously that tPA has anti-inflammatory activity in in vivo models of oedema or inflammation. The present study investigated the ability of exogenous recombinant tPA (rtPA) to reduce carrageenan-mediated oedema in mice lacking the tPA gene, testing the hypothesis that rtPA treatment may be beneficial in diseases such as RA and ARDS in which there is a paucity of endogenous tPA. Knockout mice deficient in the tPA gene and matching wild-type mice received an intraplantar injection (25 micro L) of carrageenan (1.5%, w/v) following either vehicle (sterile water for injection) or tPA (12 mg/kg). Footpad oedema was measured, an oedema index was calculated and tissue myeloperoxidase (MPO) activity was determined. Mean oedema indices were higher in untreated tPA (-/-) mice than untreated wild-type mice. Pretreatment with rtPA in either tPA (-/-) or wild-type mice reduced the mean measured peak footpad oedema index by 63 and 48%, respectively. Tissue MPO activity was not different between treatment groups. We conclude that exogenous rtPA has the ability to reduce acute oedema without altering neutrophil infiltration into the site of injury in both tPA (-/-) and wild-type mice and that endogenous tPA may participate in the inflammatory process, as evidenced by higher oedema indices in untreated tPA (-/-) mice. These data provide support for the potential clinical utility of exogenous rtPA in the treatment of inflammatory diseases, such as RA and ARDS, in which there is a paucity of tPA.

Animals↗
PubMed2006

Tissue plasminogen activator genetic polymorphisms do not influence tissue plasminogen activator release in patients with coronary heart disease.

OBJECTIVES: To determine if polymorphisms of the tissue plasminogen activator (t-PA) gene influence acute endogenous t-PA release in patients with coronary heart disease (CHD). METHODS: Forearm blood flow and plasma t-PA concentrations were measured in response to intra-brachial infusion of substance P and sodium nitroprusside in 96 patients with stable CHD. Genotyping was performed using a Taqman polymerase chain reaction assay specifically designed to detect the polymorphisms of interest: (i) Alu-repeat insertion/deletion sequence; (ii) C-->T substitution in an upstream enhancer region (-7351 C/T); (iii) T-->C in exon 6 (20 099 T/C); and (iv) T-->A (27 445 T/A) in intron 10. RESULTS: Substance P and sodium nitroprusside caused dose-dependent increases in forearm blood flow in all patients (P < 0.001 for all) that were independent of the four genetic polymorphisms. Similarly, there were no differences in basal plasma t-PA antigen concentrations or net t-PA release between genotypes. Compared to non-smokers, smokers exhibited impaired substance P-induced vasodilatation (P < 0.001) and t-PA release (P = 0.05). CONCLUSIONS: Despite confirming our previous findings in cigarette smokers, we have found no effect of polymorphisms of the t-PA gene on two complementary aspects of endothelial function. We conclude that genetic variation of the t-PA locus is unlikely to have a major influence on acute t-PA release in subjects with established CHD.

Aged↗
PubMed1996

Comparative study of a mutant tissue-type plasminogen activator, YM866, with a tissue-type plasminogen activator in a canine model of femoral arterial thrombosis.

Because tissue-type plasminogen activator (tPA), used to treat myocardial infarction, has several disadvantages thought to be connected with its low half-life, mutants of tPA have been prepared with longer half-lives. We have compared the thrombolytic effect of such a mutant, YM866, with that of tPA in copper-coil-induced femoral arterial thrombosis in dogs. One hour after thrombus formation, YM866 was administered by intravenous bolus injection, while tPA was given by the same method or by 60-min infusion under adequate heparinization. Both agents exhibited dose-dependent thrombolysis without systemic fibrinogenolysis. The recanalization rate and recanalization time of YM866 by bolus at 0.2 mg kg-1 were, however, equivalent to those of tPA by infusion at 0.4 mg kg-1 (total dose), whereas the recanalization rate of tPA by bolus was low (0.4 mg kg-1). No significant difference in reocclusion rate, reocclusion time, or patency status after successful thrombolysis was seen. These results suggest that YM866 administered at a lower dose by intravenous bolus injection exerted a thrombolytic effect equivalent to that of tPA by infusion, and that heparin could not prevent reocclusion after successful thrombolysis even under adequate anticoagulation.

Animals↗
PubMed1986

Plasminogen activator production from murine mastocytoma cells. Dissociation of plasminogen activator and histamine production by sodium butyrate.

Plasminogen activator (PA) production from mouse mastocytoma P815 was investigated. A trace level of PA was detected in the culture supernatant of P815, but addition of Con A (5 micrograms/ml) stimulated the PA production to the 20- to 50-fold of that of the unstimulated culture. Time course studies suggest that PA is actively synthesized and secreted during the culture period with Con A. Furthermore, pretreatment of P815 with sodium butyrate, which is known to differentiate interleukin-3-dependent bone marrow mast cells or P815 cells, increased the PA production from P815 cells in the presence or absence of Con A.

Animals↗
PubMed1997

Moderate genetic influences on plasma levels of plasminogen activator inhibitor-1 and evidence of genetic and environmental influences shared by plasminogen activator inhibitor-1, triglycerides, and body mass index.

Both genes and environmental factors have been reported to influence plasma levels of plasminogen activator inhibitor-1 (PAI-1). However, the relative importance of genetic influences (i.e., heritability) on plasma PAI-1 levels has not yet been investigated. Furthermore, PAI-1 levels are correlated with body mass index (BMI) and triglycerides. These correlations could reflect genetic and/or environmental factors in common to PAI-1, triglycerides, and BMI. We applied multivariate genetic analysis methods to assess the relative importance of genetic and environmental influences on plasma PAI-1 levels and to test the significance of genetic and/or environmental influences shared by PAI-1, triglycerides, and BMI in 217 pairs of middle-aged and elderly twins, of whom 113 pairs were reared apart and 121 pairs were women. The heritability estimate for PAI-1 levels was 42%. Individual-specific environmental factors explained 36% of the variance for PAI-1 levels. The remaining variance of PAI-1 was explained by rearing and residual-familial environmental factors. Furthermore, a genetic correlation of 1.00 between PAI-1 and triglycerides, a rearing environmental correlation of 1.00 between PAI-1 and BMI, a residual-familial environmental correlation of 1.00 between PAI-1 and triglycerides, and a genetic correlation of 0.63 between PAI-1 and BMI, were found. In conclusion, the present results suggest that genetic influences on plasma PAI-1 are moderate. Genetic and shared rearing or residual-familial environmental factors shared by PAI-1, BMI, and triglycerides explain the phenotypic association between these measures. It appears that all the genetic influences for PAI-1 are more or less shared with those for triglycerides and BMI.

Adoption↗
PubMed1998

Natriuretic factors and nitric oxide suppress plasminogen activator inhibitor-1 expression in vascular smooth muscle cells. Role of cGMP in the regulation of the plasminogen system.

Increased expression of plasminogen activator inhibitor-1 (PAI-1) has been reported in atherosclerotic and balloon-injured vessels. Little is known regarding the factors and mechanisms that may negatively regulate PAI-1 expression. In this report, the effect of cGMP-coupled vasoactive hormones, including natriuretic factors and nitric oxide, on the regulation of PAI-1 expression in vascular smooth muscle cells was examined. Atrial natriuretic factor 1-28 (ANF) and C-type natriuretic factor-22 (CNP) reduced angiotensin II (Ang II)- and platelet-derived growth factor-stimulated PAI-1 mRNA expression in rat aortic smooth muscle cells by 50% to 70%, with corresponding reductions in PAI-1 protein release. Treatment of human aortic smooth muscle cells with CNP similarly inhibited both platelet-derived growth factor-induced PAI-1 mRNA expression and PAI-1 protein release by 50%. Dose-response studies revealed that the inhibitory effects of CNP and ANF on PAI-1 expression were concentration dependent, with IC50s of approximately 1 nmol/L for both natriuretic peptides. Ang II-stimulated PAI-1 expression was also inhibited by the nitric oxide donor S-nitroso-N-acetylpenicillamine. The membrane-permeant cGMP analogue 8-Br-cGMP reduced Ang II-stimulated PAI-1 expression by 60%, and an inhibitor of soluble guanylyl cyclase (1H-[1,2,4]oxadiazolo[4, 3-a]quinoxalin-1-one) significantly impaired the inhibitory effects of S-nitroso-N-acetylpenicillamine on Ang II-stimulated PAI-1 expression. Studies of PAI-1 mRNA stability in cells treated with actinomycin D showed that ANF did not alter PAI-1 mRNA half-life, suggesting that natriuretic factors reduce PAI-1 transcription. These data show that natriuretic factors and nitric oxide, via a cGMP-dependent mechanism, inhibit PAI-1 synthesis in vascular smooth muscle cells. Thus, cGMP-coupled vasoactive hormones may play an important role in suppressing vascular PAI-1 expression.

Animals↗
PubMed2000

Hypertriglyceridemic VLDL downregulates tissue plasminogen activator gene transcription through cis-repressive region(s) in the tissue plasminogen activator promoter in cultured human endothelial cells.

The relationship between tissue plasminogen activator (tPA) levels and the potential regulation by hypertriglyceridemic very low density lipoprotein (HTG-VLDL) was examined in a human umbilical vein endothelial cell (HUVEC) culture model system. HUVEC cultures were incubated in the absence/presence of HTG-VLDL or normal (NTG)-VLDL (0 to 50 microg/mL) at 37 degrees C for various times (0 to 24 hours), followed by analyses of tPA antigen (ELISA), mRNA (reverse transcription-polymerase chain reaction), endothelial cell surface-localized plasmin generation assays, and nuclear transcription run-on assays. Secreted tPA antigen levels decreased approximately 53% (3.3+/-0.14 versus 6.97+/-0.42 microg/mL) and mRNA levels decreased approximately 70% in HTG-VLDL-treated HUVECs compared with NTG-VLDL-treated and culture medium control cells. Decreased tPA antigen and mRNA expression was associated with a concomitant approximately 98% decrease in tPA-mediated plasmin generation in HTG-VLDL-treated HUVEC cultures. Nuclear transcription run-on assays demonstrated that HTG-VLDL decreased tPA gene transcription approximately 73% (tPA mRNA/GAPDH mRNA) in cultured HUVECs. To identify and localize the repressive element(s) in the tPA promoter responsive to HTG-VLDL, a tPA promoter/luciferase construct (ptPA222/luc) was generated. HUVECs transiently transfected with this construct were incubated in the absence/presence of HTG-VLDL or NTG-VLDL (20 microg/mL). HTG-VLDL decreased promoter activity approximately 52% to 57% in the ptPA222/luc-transfected cells compared with NTG-VLDL-treated or buffer control cells. These results indicate that the 2.2-kb fragment of the promoter and 5' flanking region of the tPA gene contains the repressive sequences that direct the transcriptional downregulation of the tPA promoter. Data from these studies suggest that the repression of tPA gene expression by HTG-VLDL may contribute to the impaired fibrinolysis often associated with hypertriglyceridemia.

Cells, Cultured↗
PubMed2003

Promoter (4G/5G) plasminogen activator inhibitor-1 genotype and plasminogen activator inhibitor-1 levels in blacks, Hispanics, and non-Hispanic whites: the Insulin Resistance Atherosclerosis Study.

BACKGROUND: The 4G/5G polymorphism of the plasminogen activator inhibitor-1 (PAI-1) gene has been related to cardiovascular disease. METHODS AND RESULTS: Insulin resistance was measured with a frequently sampled intravenous glucose tolerance test in the Insulin Resistance Atherosclerosis Study (IRAS), and PAI-1 4G/5G promoter genotype was established by allele-specific polymerase chain reaction amplification of genomic DNA. There were 287 subjects with the 4G/4G genotype (18.4%), 691 heterozygote subjects (44.2%), and 586 carriers of the 5G/5G genotype (37.5%). The genotype distribution was different across the 3 ethnic groups (P=0.001). PAI-1 levels were lower in blacks than in non-Hispanic whites and Hispanics and lower in non-Hispanic whites than in Hispanics (all P=0.0001). Subjects homozygous for the 4G allele had the highest plasma PAI-1, heterozygote subjects were intermediate, and 5G homozygotes had the lowest levels of PAI-1. These patterns remained unaffected by adjustments for age, gender, clinical center, glucose tolerance status, body mass index, waist, triglycerides, and insulin resistance. Multiple linear regression analyses showed that the 4G/5G genotype explained very little of the variation in PAI-1 levels (0.63% in non-Hispanic whites, 0.99% in Hispanics, and 2.37% in blacks), and interaction analyses revealed no significant differences in the relation of circulating PAI-1 levels to the 4G/5G genotype by ethnicity (P=0.4). CONCLUSIONS: We have shown ethnic differences in the PAI-1 4G/5G polymorphism along with corresponding differences in circulating PAI-1 levels. The association of the genotype with PAI-1 levels was seen consistently among all 3 ethnic groups and was unaffected by metabolic covariates, including insulin resistance.

Black or African American↗
PubMed1991

A prospective, randomized trial comparing combination half-dose tissue-type plasminogen activator and streptokinase with full-dose tissue-type plasminogen activator. Kentucky Acute Myocardial Infarction Trial (KAMIT) Group.

BACKGROUND: The potential benefits of combination thrombolytic agents in the treatment of myocardial infarction remain uncertain. In a small pilot study, we demonstrated that combining half-dose tissue-type plasminogen activator (t-PA) with streptokinase (SK) achieved a high rate of infarct vessel patency and a low rate of reocclusion at half the cost of full-dose t-PA. METHODS AND RESULTS: We designed a prospective trial in which 216 patients were randomized within 6 hours of myocardial infarction to receive either the combination of half-dose (50 mg) t-PA with streptokinase (1.5 MU) during 1 hour or to the conventional dose of t-PA (100 mg) during 3 hours. Acute patency was determined by angiography at 90 minutes, and angioplasty was reserved for failed thrombolysis. Heparin and aspirin regimens were maintained until follow-up catheterization at day 7. Acute patency was significantly greater after t-PA/SK (79%) than with t-PA alone (64%, p less than 0.05). After angioplasty for failed thrombolysis, acute patency increased to 96% in both groups. Marked depletion of serum fibrinogen levels occurred after t-PA/SK compared with t-PA alone at 4 hours (37 +/- 36 versus 199 +/- 66 mg/dl, p less than 0.0001) and persisted 24 hours after therapy (153 +/- 66 versus 252 +/- 75 mg/dl, p less than 0.0001). Reocclusion (3% versus 10%, p = 0.06), reinfarction (0% versus 4%, p less than 0.05), and need for emergency bypass surgery (1% versus 6%, p = 0.05) tended to be less in the t-PA/SK group. Greater myocardial salvage was apparent in the t-PA/SK group as assessed by infarct zone function at day 7 (-1.9 SD/chord versus -2.3 SD/chord after t-PA alone, p less than 0.05). In-hospital mortality (6% versus 4%) and serious bleeding (12% versus 11%) were similar between the two groups. CONCLUSIONS: These results suggest that a less expensive regimen of half-dose t-PA with SK yields superior 90-minute patency and left ventricular function and a trend toward reduced reocclusion compared with the conventional dose of t-PA.

Adolescent↗
PubMed2005

Comprehensive survey of common genetic variation at the plasminogen activator inhibitor-1 locus and relations to circulating plasminogen activator inhibitor-1 levels.

BACKGROUND: Using a linkage disequilibrium (LD)-based approach, we sought to comprehensively define common genetic variation at the plasminogen activator inhibitor-1 (PAI-1) locus and relate common single nucleotide polymorphisms (SNPs) and haplotypes to plasma PAI-1 levels. METHODS AND RESULTS: In reference pedigrees, we defined LD structure across a 50-kb genomic segment spanning the PAI-1 locus via a dense SNP map (1 SNP every 2 kb). Eighteen sequence variants that capture underlying common genetic variation were genotyped in 1328 unrelated Framingham Heart Study participants who had plasma PAI-1 antigen levels measured. Regression analyses were used to examine associations of individual SNPs and of inferred haplotypes with multivariable-adjusted PAI-1 levels. Two genetic variants, SNP rs2227631 and the 4G/5G polymorphism, were strongly associated (P<0.0001) with PAI-1 levels. SNP rs2227631 is in tight LD (D'=0.97, r2=0.78) with the 4G/5G polymorphism, which makes it difficult to distinguish which of these 2 polymorphisms is responsible for the association with PAI-1 levels. In stepwise analysis considering all polymorphisms tested, 3 SNPs, rs2227631 (or the correlated 4G/5G polymorphism), rs6465787, and rs2227674, each explained 2.5%, 1%, and 1%, respectively, of the residual variance in multivariable-adjusted PAI-1 levels (stepwise P<0.0001, P=0.04, and P=0.03, respectively). A single common haplotype, at 50% frequency among Framingham Heart Study participants, was strongly associated with higher PAI-1 levels (haplotype-specific P=0.00001). The susceptibility haplotype harbors the minor alleles of SNP rs2227631 and the 4G/5G polymorphism. CONCLUSIONS: Three sequence variants at the PAI-1 locus, in sum, explain approximately 5% of the residual variance in multivariable-adjusted PAI-1 levels. For quantitative cardiovascular traits such as circulating biomarkers, defining LD structure in a candidate gene followed by association analyses with both SNPs and haplotypes is an effective approach to localize common susceptibility alleles.

Aged↗
PubMed1995

Determinants of plasminogen activator inhibitor 1 activity in treated NIDDM and its relation to a polymorphism in the plasminogen activator inhibitor 1 gene.

Plasminogen activator inhibitor 1 (PAI-1) activity is increased in patients with non-insulin-dependent diabetes mellitus (NIDDM) and may contribute to their excess risk of cardiovascular disease. We examined the determinants of PAI-1 activity in 146 NIDDM subjects by using specific assays of insulin and intact and des-31,32-proinsulin and measures of insulin resistance, relating these measurements to serum lipids, hypoglycemic therapy, and a common 4G/5G polymorphism in the promoter region of the PAI-1 gene. Subjects were treated with insulin, sulfonylurea, sulfonylurea plus metformin, metformin, and diet alone. In the whole group, PAI-1 activity correlated significantly with serum triglycerides (r = 0.39, P < 0.001), specific insulin (r = 0.29, P < 0.001), intact proinsulin (r = 0.24, P = 0.004), and des-31,32-proinsulin (r = 0.30, P < 0.001) and in subjects not on insulin (n = 110), with insulin sensitivity (r = -0.42, P < 0.001). There was a significant difference in PAI-1 activity among the three genotypic groups (P = 0.016); subjects with the genotype 4G/4G had PAI-1 levels one-third higher than those with the 5G/5G genotype. In the 4G/4G group, PAI-1 activity correlated significantly with triglyceride levels (r = 0.65, P < 0.0001). There was no significant difference in PAI-1 activity in the different treatment groups despite a significant difference in concentrations of intact and des-31,32-proinsulin. In a multiple regression model, insulin sensitivity and the interaction between PAI-1 4G/5G genotype and triglyceride were the strongest determinants of PAI-1 activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

[Comparative randomized study of the effectiveness of intravenous recombinant tissue-type plasminogen activator and intravenous streptokinase in patients with acute myocardial infarct. Report of the European Cooperative Study Group for Recombinant Tissue-Type Plasminogen Activator].

In a single-blind randomised trial in patients with acute myocardial infarction of less than 6 h duration, the frequency of coronary patency was found to be higher after intravenous administration of recombinant human tissue-type plasminogen activator (rt-PA) than after intravenous streptokinase. 64 patients were allocated to 0.75 mg rt-PA/kg over 90 min, and the infarct-related coronary artery was patent in 70% of 61 assessable coronary angiograms taken 75-90 min after the start of infusion; 65 patients were allocated to 1,500,000 IU streptokinase over 60 min, and the infarct-related vessel was patent in 55% of 62 assessable angiograms. The 95% confidence interval of the difference ranges from +30 to -2% (p = 0.054). Bleeding episodes and other complications were less common in the rt-PA patients than in the streptokinase group. Hospital mortality was identical in the 2 treatment groups. At the end of the rt-PA infusion the circulating fibrinogen level was 61 +/- 35% of the starting value, as measured by a coagulation-rate assay, and 69 +/- 25% as measured by sodium sulphite precipitation. After streptokinase infusion, corresponding fibrinogen levels were 12 +/- 18% and 20 +/- 11%. In the rt-PA group only 4.5% of the fibrinogen was measured as incoagulable fibrinogen degradation products, compared with 30% in the streptokinase group. Activation of the systemic fibrinolytic system was far less pronounced with rt-PA than with streptokinase.

Adult↗
PubMed1985

[Analysis of plasminogen activator in human plasma using the method of fibrin/celite column chromatography--with special reference to the determination of fibrin adsorbable tissue-plasminogen activator by ELISA].

To clarify the clinical importance of tissue-plasminogen activator (t-PA) on the thrombosis, it is essential to be measured t-PA level in human plasma. Taking advantage of strong affinity of t-PA to fibrin, t-PA was isolated with Fibrin/Celite column chromatography. Immunological activities of t-PA of plasma samples determined by ELISA and the elution pattern of it on Fibrin/Celite column chromatography were studied. The results are as follows: The t-PA in human plasma was consisted of fibrin adsorbable t-PA and fibrin nonadsorbable t-PA. Both types of t-PA could be measured separately by using of Fibrin/Celite column chromatography. The fibrin adsorbable t-PA fraction showed two types of molecular size (major peak was Mr congruent to 70,000, minor peak was Mr congruent to 100,000) on Sephadex G-200 chromatography. The level of t-PA in plasma samples taken from 20 healthy subjects at rest was 2.4 +/- 1. 9 ng/ml, and concentration of t-PA increased to 10.4 +/- 3.2 ng/ml after venous stasis. But the t-PA level of plasma samples from patients with cerebral thrombosis did not increase after venous stasis. The changes of immunologically determined t-PA in plasma samples induced by venous stasis were not reflected in the fibrinolytic activities of the euglobulin fractions, but well reflected in the fibrinolytic activities of the elution fractions on Fibrin/Celite column chromatography. The level of fibrin nonadsorbable t-PA did not change by venous stasis, but the level of fibrin adsorbable t-PA increased from 5.1 +/- 1.9 ng/ml to 9.7 +/- 2.7 ng/ml in the case of 6 healthy subjects. It is concluded that, the plasma t-PA increased by venous stasis was the fibrin adsorbable t-PA, and it may play a very important role in physiological fibrinolysis.

Adsorption↗