Tissue Plasminogen Activator Activity Research Articles

Targeted introduction of tissue plasminogen activator (TPA) at the AAVS1 locus in mesenchymal stem cells (MSCs) and its stable and effective expression

Thrombolytic therapy using tissue plasminogen activator (TPA) is an effective method for treating acute myocardial infarction. However, the systemic administration of TPA is associated with the risk of hemorrhage. Mesenchymal stem cells (MSCs) from bone marrow are characterized by low immunogenicity and homing toward damaged tissues and are therefore ideal cell carriers to achieve lesion-targeting medication. In this article, TPA gene was integrated into the AAVS1 of mesenchymal stem cells, which has been confirmed to be a safe chromosomal locus. The targeting efficiency was 83%. The clones with the site-specific integration retained the stem cell traits of MSCs, displayed a normal karyotype and could persistently and effectively express TPA, as demonstrated by an average expression activity of 1.5units/mL (3.4-fold that of the control group). After subculture and subsequent growth for two weeks, the clones showed an average TPA activity of 1.43units/mL and exhibited no significant differences among the individual clones. In summary, the foreign TPA gene can be specifically introduced to the AAVS1 locus, whereby it can be stably and effectively expressed. MSCs can serve as cell carriers for the targeted treatment of a thrombus using TPA.

DYNAMICS OF CARDIOVASCULAR STATUS AND SERUM MARKERS OF ENDOTHELIAL DYSFUNCTION IN PATIENTS WITH RHEUMATOID ARTHRITIS, TREATED WITH INFLIXIMAB

Aim. To assess the complex dynamics of the main parameters of cardiovascular status and serum markers of endothelial dysfunction (ED) in patients with rheumatoid arthritis (RA), who were treated with infliximab.Material and methods. The main group (MG) included 50 patients with seropositive RA, who received a combination of methotrexate and infliximab. The examination took place at baseline, as well as two, six, and 14 weeks after the treatment started. Comparison groups (CG) included healthy volunteers (n=25) and RA patients treated with methotrexate only (n=110). Serum levels of tumor necrosis factor-α (TNO-α), interleukin-10 (IL-10), tissue plasminogen activator (TPA), and von Willebrand factor (vWf) were measured, using ELISA. Left ventricular (LV) function and microvascular status were assessed with echocardiography and laser Doppler flowmetry (LDF), respectively.Results. The E/A ratio was reduced in all subgroups, and at Week 14 of infliximab therapy, it slightly increased. At baseline, LDF parameters, such as neurogenic arteriole tone and intravascular resistance, were increased. Infliximab therapy was associated with a moderate decline of these parameters. Throughout the study, serum vWf concentration was higher in MG patients than in healthy controls. TPA activity was reduced at baseline (496±173 pg/ml), increasing at Week 14 up to 705±157 pg/ml. Baseline concentrations of TNF-α and UL-10 were substantially elevated (357,1±34 and 453±42 pg/ml, respectively). At Week 6, TNF-α concentration decreased significantly. At Week 14, not only TNF-α level decreased, reaching 94±28 pg/ml, but also the ratio TNF-α/IL-10 decreased (from 0,78±0,5 to 0,4±0,2).Conclusion. In RA patients, infliximab was highly effective for the functional cytokine dysbalance correction, also demonstrating pleiotropic effects, such as correction of microvascular and endothelial dysfunction.

The Kringle-2 domain of tissue plasminogen activator significantly reduces mortality and brain infarction in middle cerebral artery occlusion rats

Tissue plasminogen activator (TPA) showed brain-protective activity within the first 15 min after cerebral ischemia in rats. To understand its molecular mechanism, TPA derivates were intracerebroventricularly administered at 15 min before, and 15, 90, 120 min after middle cerebral artery occlusion (MCAO) in rats. The reduction in mortality and cerebral infarction at 24 h was seen only with TPA administered at 15 min after MCAO. The down-regulation of endogenous TPA by the intracerebroventricular injection of TPA was found to be responsible for the protective effect on the integrity of blood-brain barrier after MCAO, as well as for the reduction in mortality and cerebral infarction. Moreover, for the first time we have found that the Kringle-2 domain is essential for the brain-protective activity of TPA.

Ultrasound Enhanced Thrombolysis: Applications in Acute Cerebral Ischemia

Intravenous tissue plasminogen activator (TPA) improves patient chances to recover from stroke by inducing mostly partial recanalization of large intracranial thrombi. TPA activity can be enhanced with ultrasound including 2 MHz transcranial Doppler (TCD). TCD identifies residual blood flow signals around thrombi, and, by delivering mechanical pressure waves, exposes more thrombus surface to circulating TPA. The international multi-center CLOTBUST trial showed that ultrasound enhances thrombolytic activity of a drug in humans thereby confirming multi-disciplinary experimental research conducted worldwide for the past 30 years.In the CLOTBUST trial, the dramatic clinical recovery from stroke coupled with complete recanalization within 2 hours after TPA bolus occurred in 25% of patients treated with TPA+TCD compared to 8% who received TPA alone (p=0.02). Complete clearance of a thrombus and dramatic recovery of brain functions during treatment are feasible goals for ultrasound-enhanced thrombolysis that can lead to sustained recovery. An early boost in brain perfusion seen in the Target CLOTBUST group resulted in a trend of 13% more patients achieving favorable outcome at 3 months, subject for a pivotal trial. However, different results were achieved in a small TRUMBI trial and another study that used Transcranial Color-Coded Duplex Sonography (TCCD). Adverse bio-effects of mid-KHz (300) ultrasound promote bleeding, including brain areas not-affected by ischemia while exposure to multi-frequency / multi-element duplex ultrasound resulted in a trend towards higher risk of hemorrhagic transformations.To further enhance the ability of TPA to break up thrombi, current ongoing clinical trials include phase II studies of a single beam 2 MHz TCD with perflutren-lipid microspheres. Enhancement of intra-arterial TPA delivery is being clinically tested with 1.7-2.1 MHz pulsed wave ultrasound (EKOS catheter). Multi-national dose escalation studies of microspheres and the development of an operator independent ultrasound device are underway.

Ultrasound Enhanced Thrombolysis for Stroke

Spontaneous arterial recanalization occurs at a rate of 6% per hour, and it can be doubled with intravenous tissue plasminogen activator (TPA) therapy since early dramatic clinical improvement, a substitute for early thrombus break-up, occurs in TPA-treated patients. TPA activity can be enhanced with ultrasound including 2-MHz transcranial Doppler (TCD). TCD identifies residual blood flow signals around thrombi, and, by delivering mechanical pressure waves, exposes more thrombus surface to circulating TPA. In the CLOTBUST trial, the dramatic clinical recovery from stroke coupled with complete recanalization within 2 hours after TPA bolus occurred in 25% of patients treated with TPA+TCD compared with 8% who received TPA alone ( P = 0.02). Complete clearance of a thrombus and dramatic recovery of brain function during treatment are feasible goals for ultrasound-enhanced thrombolysis that can lead to sustained recovery. An early boost in brain perfusion seen in the Target CLOTBUST group resulted in a trend of 13% more patients achieving favorable outcome at 3 months, thus providing the rationale for a pivotal trial. The ability of TPA to break up thrombi can be further enhanced with harmless diagnostic ultrasound contrast agents. Current ongoing clinical trials include phase II studies of 2-MHz TCD with ultrasound contrast agents, or microbubbles: TCD+TPA+Levovist; TCD+TPA+MRX nano-platform (C 3 F 8 ImaRx). Intraarterial ultrasound-enhanced TPA delivery is tested in the Interventional Management of Stroke (IMS) clinical trial using 1.7- to 2.1-MHz pulsed-wave ultrasound catheter (EKOS). Dose escalation studies of microbubbles, ultrasound exposure, and the development of an operator-independent ultrasound device are currently underway.

Ultrasound-enhanced thrombolysis for stroke: clinical significance

In the pivotal clinical trials of intravenous tissue plasminogen activator (TPA) therapy for ischemic stroke, a low rate of early arterial recanalization was suspected due to the small numbers of patients who had early dramatic clinical improvement. TPA activity can be enhanced with ultrasound including 2 MHz transcranial Doppler (TCD). TCD can identify residual signals around the thrombus with the thrombolysis in brain ischemia (TIBI) flow grading system and therefore expose more thrombus surface to circulating TPA. A phase I clinical study, monitoring TPA infusion with diagnostic ultrasound resulted in an unexpectedly high rate of complete recanalization (36% of proximal middle cerebral artery (MCA) occlusions) and associated early dramatic clinical recovery (24%) among treated patients. The external application of diagnostic ultrasound in our studies raised the possibility that a synergistic TPA and ultrasound action accelerated flow improvement and achieved faster and more complete thrombus dissolution as predicted from experimental models. The CLOTBUST (combined lysis of thrombus in brain ischemia using transcranial ultrasound and systemic TPA) trial is testing this hypothesis in a phase II clinical randomized multi-center setting. Dramatic clinical recovery from stroke and complete recanalization shortly after TPA bolus are feasible goals for thrombolysis assisted with TCD monitoring.

Plasminogen activators in multiple sclerosis lesions: implications for the inflammatory response and axonal damage.

Components of the plasminogen activator (PA) and matrix metalloprotease (MMP) cascade have been characterized in multiple sclerosis lesions by immunohistochemistry, enzyme-linked immunosorbent assay and enzyme activity assays in order to establish a functional role for the enzyme sequence in lesion development. Highly significant quantitative increases in urokinase PA (uPA), urokinase receptor (uPAR) and plasminogen activator inhibitor-1 were detected in acute multiple sclerosis lesions (P < 0.0001) and in uPAR in normal-appearing white matter (P < 0.0001) compared with control tissue. All three proteins were immunolocalized to mononuclear cells in perivascular cuffs and to macrophages in the lesion parenchyma. MMP-9 and the tissue inhibitor of metalloprotease-1 also increased during lesion development but the enzyme was present largely in the inactive pro-form. In contrast to uPA, the concentration and activity of tissue PA (tPA), the most abundant plasminogen activator in normal control brain, were reduced in multiple sclerosis specimens. In acute lesions tPA co-localized with fibrin(ogen) on large diameter axons also stained with SMI-32, an immunohistochemical marker of axonal damage. The uPA-uPAR complex, concentrated on inflammatory cells in the perivascular zone of the evolving lesion, may facilitate cellular infiltration into the CNS which is amplified by MMP- mediated degradation of blood vessel matrix. tPA localization on injured axons may be a marker of axonal damage or represent a protective mechanism aimed at removal of fibrin deposits and restoration of axonal function.

Circulating levels of plasminogen activator inhibitor type-1, tissue plasminogen activator, and thrombomodulin in hemodialysis patients: biochemical correlations and role as independent predictors of coronary artery stenosis.

This study investigated the relationship between the circulating levels of the endothelial cell glycoproteins plasminogen activator inhibitor type 1 (PAI-1), tissue plasminogen activator (TPA), and thrombomodulin (TM) and the major vascular risk factors described in dialysis patients. In addition, the role of these endothelial cell products as independent predictors of coronary artery disease (CAD) was analyzed. Levels of TM, TPA antigen (Ag), TPA activity, PAI-1 Ag, PAI-1 activity, TPA/PAI complexes, thrombin-antithrombin complexes, fibrinopeptide A, C-reactive protein (CRP), interleukin-1beta and tumor necrosis factor-alpha, lipids, apoproteins A1 and B, and albumin were measured in a group of 200 nondiabetic dialysis patients and 100 healthy matched volunteers. When compared with healthy controls, dialysis patients showed increased levels of CRP, TM, TPA, and PAI-1 and evidence of increased thrombin-dependent fibrin formation. Increased levels of active PAI-1 were associated to a great extent with major classic vascular risk factors and to a lesser extent with CRP and serum triglycerides. Forty-six patients (23%) had evidence of CAD. Variables associated with CAD in the univariate analysis included age, time on dialysis, male gender, number of packs of cigarettes per year, high BP, fibrinogen, apolipoprotein B, albumin, PAI-1 activity, CRP, thrombin-antithrombin complexes, and fibrinopeptide A. Logistic regression analysis found age, high-density lipoprotein cholesterol, gender, high BP, CRP, time on dialysis, and PAI-1 activity to be independent predictors of CAD. This model classified correctly 85% of patients as having CAD and showed adequate goodness of fit for all risk categories. Our data support a pathogenic link among activated inflammatory response, endothelial injury, and CAD in hemodialysis patients and suggest that assessment of circulating PAI-1 levels could be an additional tool to identify dialysis patients who are at risk for developing atheromatous cardiovascular disease.

Temporal activity of plasminogen activators and matrix metalloproteinases during cutaneous wound repair

Background: Response to tissue injury begins with the deposition of a fibrin-rich clot or the provisional matrix. The provisional matrix consists of plasma-borne matrix molecules that serve as scaffolding for the ensuing migration of cells. During wound repair multiple cell types must migrate through the clot-matrix scaffolding. The migration of these cells through the matrix is dependent on the activity of the fibrinolytic and proteolytic systems, which include the plasminogen activator (PA) system and matrix metalloproteinases (MMP). The aim of this study was to better understand the temporal activity of these enzymes during normal wound repair. Methods: We used the murine excisional wound model and extracted proteins under nonreducing conditions. With use of gelatin and casein zymography, we determined the activity of the MMPs during the course of wound repair. In addition, we quantified the activity of MMP-2 and MMP-9 by a standardized assay. Plasminogen zymograms were used to detect urokinase PA and tissue PA activity. Western blots were used to detect the natural inhibitor of PAs, plasminogen activator inhibitor type 1. Results: Our results demonstrate the temporal activity of MMP-2, MMP-3, MMP-7, and MMP-9 during the course of normal dermal repair. The activity of urokinase PA and tissue PA were also determined; it preceded the activity of the MMPs. Conclusions: We demonstrate the temporal activity of the 2 protease families, MMPs and PAs, in the normal process of cutaneous wound healing. (Surgery 1999;125:587-93.)

Heparin-coated bypass circuits (Carmeda) suppress the release of tissue plasminogen activator during normothermic coronary artery bypass graft surgery

Objectives: To study fibrinolysis in a homogenous first-time coronary artery bypass surgery (CABG) population in whom heparin-coated circuits were used.Design: A prospective, blinded, randomized, placebocontrolled study.Setting: A university hospital, tertiary care, intraoperative and postoperative intensive care unit.Participants: Twenty-one adult elective primary CABG patients.Interventions: Randomized circuit-type centrifugal pump, membrane oxygenator, rigid cardiotomy reservoir, either placebo (n = 10) or heparin-coated (n = 11) (Carmeda; Medtronic Inc., Anaheim, CA).Measurements and Main Results: Blood samples were analyzed for tissue plasminogen activator (TPA) activity, TPA antigen, plasminogen activator inhibitor-1 (PAI-1) activity, prothrombin complex F1.2, and antithrombin III (AT-III) at the following times: before cardiopulmonary bypass (CPB), during CPB (30 and 60 minutes), post-CPB, and day 1 postsurgery. TPA activity and antigen increased fivefold in the placebo group during CPB, whereas it did not even double in the heparin-coated group. PAI-1, F1.2, and AT-III were not different between groups.Conclusions: Heparin-coated CPB circuits reduced TPA release in this homogenous CABG population with routine heparin/protamine management.

Plasminogen activator expression in rat arterial smooth muscle cells depends on their phenotype and is modulated by cytokines.

Cultured rat aortic smooth muscle cells (SMCs) exhibit at least 2 phenotypic variants: (1) a spindle-shaped phenotype, obtained from normal adult media, and (2) an epithelioid phenotype, obtained from intimal thickening 15 days after endothelial injury. Both phenotypes can be cloned from each location, with normal media yielding a majority of spindle-shaped clones and intimal thickening yielding a majority of epithelioid clones. These findings suggest that intimal thickening develops essentially from a subpopulation of medial SMCs exhibiting epithelioid features in vitro. Using zymographic and Northern blot analyses, we have studied plasminogen activator (PA) expression by these SMCs. Our results show that epithelioid SMCs, cultured as whole SMC populations or as clones, display higher PA activity than do spindle-shaped SMCs, irrespective of their origin. This is mainly due to differences in the expression of tissue PA and, to a lesser extent, urokinase PA and is accompanied by a decrease in PA inhibitor 1. Tissue PA activity is increased by basic fibroblast growth factor and platelet-derived growth factor-BB, particularly in epithelioid SMCs. Taken together, these results indicate that SMCs are heterogeneous with respect to their proteolytic profile, at least as far as the PA system is concerned. Proteolytic activity of the different SMC populations is modulated by cytokines that play a role in intimal thickening. Our results are in agreement with the suggestion that epithelioid SMCs are mainly responsible for intimal thickening.

Fibrinolytic responses to moderate intensity exercise. Comparison of physically active and inactive men.

The purposes of this study were to compare fibrinolytic responses to moderate intensity exercise in physically active and inactive men and during morning and evening exercise. Fourteen physically inactive men (mean age, 34.7 +/- 4.0 years) and 12 regularly active men (34.8 +/- 4.0 years) performed two exercise sessions, morning and evening, at 50% of maximal oxygen consumption. Tissue plasminogen activator (TPA) and plasminogen activator inhibitor-1 (PAI-1) activity were measured before and after exercise. Data were analyzed using a three-way ANOVA with repeated measures. TPA activity increased with exercise in both groups, although the active group demonstrated greater increases than the inactive group. Postexercise TPA activity was greater with evening than morning exercise. The inactive group exhibited greater PAI-1 activity than the active group. PAI-1 activity was higher during the morning than evening but did not change with exercise for either group. We conclude that moderate intensity exercise increases TPA activity in physically active and inactive men, with greater increases seen in active men, particularly during evening exercise. Moderate intensity exercise does not appear to affect PAI-1 activity. The lower PAI-1 activity in active men may be one mechanism whereby regular physical activity lowers the risk for coronary artery disease.

Effects of maximal exercise and venous occlusion on fibrinolytic activity in physically active and inactive men

The purposes of this study were to 1) characterize changes in fibrinolytic activity in response to maximal exercise and 5-min venous occlusion and 2) compare responses in men of various habitual physical activity levels. Tissue plasminogen activator (TPA) activity and plasminogen activator inhibitor 1 (PAI-1) activity were measured in 15 inactive, 15 regularly active, and 15 highly active men. Data were analyzed using a three-way analysis of variance with repeated measures. Pretest TPA activity was similar among groups. TPA activity increased postexercise with higher values seen in the active groups (P < 0.001). The highly active group also significantly increased TPA activity postvenous occlusion (P < 0.01). Pretest PAI-1 activity was different among groups, with the inactive group showing the highest activity and the highly active group the lowest (P < 0.05). PAI-1 activity decreased with exercise (P < 0.01) but did not change with venous occlusion. In conclusion, active men exhibited greater changes in fibrinolytic activity with maximal exercise and venous occlusion than inactive men. This enhanced fibrinolytic activity may be an important mechanism mediating the cardioprotective effect provided by regular physical activity.

Effects of exercise intensity, duration, and time of day on fibrinolytic activity in physically active men

The purposes of this investigation were to determine: 1) whether the fibrinolytic responses to acute, submaximal exercise were best related to intensity, duration, or total caloric expenditure; and 2) whether the time of day exercise is performed affects the fibrinolytic response. Twelve physically active men (mean age = 34.8 +/- 4.0 yr) performed four 30-min exercise sessions: 50% VO2max, a.m. and p.m., and 80% VO2max, a.m. and p.m. Blood samples were analyzed for tissue plasminogen activator (TPA) activity and plasminogen activator inhibitor-1 (PAI-1) activity. Data were analyzed using a three-way ANOVA with repeated measures. TPA activity: preexercise TPA did not differ among the four sessions. TPA increased with exercise in all sessions except the 50% a.m. session. Exercise at 80% increased TPA more than 50% (P < 0.001) and evening sessions increased TPA more than morning sessions (P < 0.05). PAI-1 activity: preexercise PAI-1 activity was higher during the morning than evening and significantly decreased with exercise in all sessions except the 50% p.m. session. It was concluded that changes in fibrinolytic activity appear to be influenced primarily by exercise intensity rather than duration or total caloric expenditure. Additionally, time of day of exercise performance significantly influenced fibrinolytic activity.

Variable response of tissue parameters of the fibrinolytic system to unilateral or bilateral adrenalectomy and unilateral or bilateral adrenal demedullation

The effect of unilateral and bilateral adrenalectomy, unilateral and bilateral demedullation or unilateral adrenalectomy/unilateral demedullation on tissue plasminogen activator activity (PAA), plasminogen activator inhibition (PAI) and plasmin inhibition (PI) was studied in the rat. All the above treatments induced an increase of PAA in lungs. Increased PAA was also noted in brain after bilateral adrenalectomy or demedullation, as well as unilateral adrenalectomy/unilateral demedullation. In kidneys the PAA was decreased after bilateral adrenalectomy or demedullation and unilateral adrenalectomy/unilateral demedullation. In aorta only after bilateral adrenalectomy a decreased PAA was induced. In heart and liver no changes in PAA were noted. A decreased PAI expressed against tissue-type plasminogen activator (t-PA) and urokinase-type plasminogen activator (u-PA) was found in lungs of all treated rats compared to controls. However, an increased PAI was noted in heart, liver and aorta against t-PA or u-PA after bilateral adrenalectomy and in liver after bilateral demedullation as well as after unilateral adrenalectomy/unilateral demedullation (rats with only one adrenal cortex). A dissociation between anti-t-PA and anti-u-PA response was seen in heart, liver and aorta. A variable change in PI was induced in kidneys, aorta, lungs and brain in all treatments except unilateral demedullation or unilateral adrenalectomy. Therefore, the effect of adrenalectomy or demedullation on tissue PAA, PAI and PI was variable and dependent on the extent of the treatment (unilateral or bilateral), the organ as well as the time after the treatment.

Fibrinolytic defect in chronic back pain: A controlled study of plasminogen activator activity in 20 patients

We analyzed the fibrinolytic system in patients with chronic low back pain using a venous occlusion test to stimulate fibrinolysis, and we subsequently determined the levels of tissue plasminogen activator (TPA) and fast-acting inhibitor of TPA (PAI). There were 20 patients with a mean age of 50 years. Two thirds had radiographically spinal stenosis. Scar tissue around the spinal nerves was seen in 11 cases. Thirteen patients had undergone back surgery, whereas 21 healthy subjects served as controls. In the basal samples, TPA activity was decreased in the patients while TPA antigen level was increased compared with the controls. No clear explanation for this defective function of TPA in the patients was obtained, because no difference was seen in PAI level in basal samples. After the venous occlusion, no difference was observed in TPA activity between the two groups excluding the constitutionally defective fibrinolytic system in the patients. However, our results confirm low basal fibrinolytic activity in patients with chronic low back pain with manifest spinal pathology.

Variable effect of unilateral or bilateral ovariectomy performed in young or adult animals on tissue plasminogen activator activity, plasminogen activator inhibition and plasmin inhibition

Unilateral or bilateral ovariectomy was performed in young and adult rats. Mainly bilateral ovariectomy induced variable changes of plasminogen activator activity (PAA), plasminogen activator inhibition (PAI) and plasmin inhibition (PI) in key organs (brain, lungs, heart, aorta and kidneys). The most remarkable changes were induced after bilateral ovariectomy performed in young animals and mostly after two and three months of ovariectomy. Therefore, the effect of ovariectomy on tissue PAA, PAI or PI was variable and dependent on the extent of the ovariectomy (unilateral or bilateral), the age of the animal at ovariectomy (young or adult), the time after ovariectomy, and the organ. An additional interesting finding was the dissociation in the response of tissue anti-t-PA and anti-u-PA activities to ovariectomy in some of the organs studied.

Effect of Orchidectomy on Tissue Plasminogen Activator Activity, Plasminogen Activator Inhibition and Plasmin Inhibition

The effect of unilateral or bilateral orchidectomy on tissue plasminogen activator activity (PAA), plasminogen activator inhibition (PAI) and plasmin inhibition (PI) was studied in the rat. Orchidectomy was performed in young or adult rats. Unilateral orchidectomy affected only PI in the lungs and brain, 1, 2 and 3 months after orchidectomy was performed in adult rats. Bilateral orchidectomy performed in young or adult rats affected one or more of the parameters studied in one or more of the key organs (brain, lungs, kidneys, heart, aorta), in most cases only 2 and 3 months after orchidectomy. Therefore, the effect of orchidectomy on tissue PAA, PAI or PI was variable and dependent on the extent of the orchidectomy (unilateral or bilateral), the age of the animal at orchidectomy, the time after orchidectomy, and the organ.

健常人におけるｔｉｓｓｕｅ ｐｌａｓｍｉｎｏｇｅｎ ａｃｔｉｖａｔｏｒ（ＴＰＡ），ｔｉｓｓｕｅ ｐｌａｓｍｉｎｏｇｅｎ ａｃｔｉｖａｔｏｒ ｉｎｈｉｂｉｔｏｒ（ＰＡＩ‐１）と血清脂質との関連性についての研究

It is well known that abnormality of the coagulation-fibrinolytic system and serum lipids plays an important role in the development of thrombi and atherosclerotic disease. In the present study, the correlation between the activity of tissue plasminogen activator (TPA), the levels of tissue plasminogen activator inhibitor (PAI-1) and serum lipids (TC, TG, beta-Lp, HDLC, LDLC and apolipoproteins) were studied in 102 healthy subjects. The activity of TPA showed negative correlation with the obesity rate (r = 0.21, p less than 0.05) but levels of PAI-1 antigen showed a positive correlation with the obesity rate (r = 0.182, p less than 0.1). The activity of TPA showed no correlation with serum lipids including apolipoproteins, while the levels of PAI-1 antigen showed a positive correlation between TG and beta-Lp (r = 0.292, p less than 0.01, r = 0.211, p less than 0.05). The levels of PAI-1 antigen showed a negative correlation with HDLC (r = -0.286, p less than 0.01). These results indicate that TPA and PAI-1 play an important role in the development of thrombotic disease and atherosclerotic disease.

Prolactin Inhibits Plasminogen Activator Activity in the Preovulatory Follicles

The present study was designed to determine the effects of PRL on changes in morphology and plasminogen activator (PA) activity in the preovulatory follicles. Rabbit ovaries were perfused with hCG alone or with hCG plus at 10, 10(2), or 10(3) ng/ml. PRL at 10(3) ng/ml directly inhibited the degeneration and decomposition of surface epithelial cells induced by hCG exposure. The subsurface connective tissue was visualized by treatment with sodium dodecyl sulfate, which removed surface epithelial cells from the ovary, thereby exposing collagen fibrils and the basal lamina. Sodium dodecyl sulfate treatment revealed inhibition of connective tissue disruption at the apex of the follicle wall in PRL-treated ovaries. PA activity in mature follicles in perfused rabbit ovaries exposed to hCG increased from 1.40 +/- 0.08 to 28.4 +/- 4.25 IU/g tissue after 4 h of perfusion. The addition of PRL to the perfusate inhibited the hCG-stimulated increase in intrafollicular PA activity in a dose-dependent fashion. Although at 7 h mature follicles treated by hCG alone showed greater intrafollicular PA activity than those treated with hCG plus PRL, this difference was not significant. These results suggest that PRL may act directly by interfering with mechanical events within the ovary that are required for the rupture of mature Graafian follicles, probably via the inhibition of intrafollicular tissue PA activity.