Impaired fibrinolysis and insulin resistance in patients with hypertension

Plasma plasminogen activator inhibitor type 1 (PAI-1) and tissue plasminogen activator (tPA) antigens and activities were measured in 28 patients with hypertension and 12 normal controls. Steady state plasma glucose (SSPG) concentrations were also determined after an infusion of somatostatin, insulin and glucose. Patients with hypertension were further subdivided into two groups: insulin resistance (SSPG > 190 mg/dL, n = 14) and no insulin resistance (SSPG < 190 mg/dL, n = 14). As compared to normal controls, hypertensive patients, either with or without insulin resistance, had significant (P < .005) increases in PAI-1 activity (18.6 ± 1.3 ν 8.1 ± 0.8 IU/mL), PAI-1 antigen (31.1 ± 2.0 ν 12.7 ± 0.9 ng/mL) and tPA antigen (15.5 ± 0.9 ν 8.8 ± 0.9 ng/mL), and significant decrease in tPA activity (0.43 ± 0.05 ν 1.02 ± 0.16 IU/mL) than normotensive controls. Furthermore, hypertensive patients with insulin resistance had significantly higher PAI-1 activity (22.0 ± 2.2 ν 15.3 ± 0.8 IU/mL, P = .006) and tPA antigen (17.4 ± 1.2 ν 13.6 ± 1.3 ng/mL, P = .02) than did hypertensive patients without insulin resistance. However, PAI-1 antigen was insignificantly higher (34.1 ± 2.9 ν 28.1 ± 2.4 ng/mL, P = .06) and tPA activity insignificantly lower (0.42 ± 0.08 ν 0.43 ± 0.08 IU/mL, P = .45) in hypertensive patients with insulin resistance than in those without insulin resistance. In addition, PAI-1 activity and tPA antigen were significantly correlated with blood pressure, SSPG, triglyceride, HDL-cholesterol and integrated glucose response to an oral load of 75 g glucose. Thus, patients with hypertension have impaired fibrinolytic activity due to increased PAI-1 when compared to normotensive controls, and the magnitude of this fibrinolytic defect is greater in hypertensive patients who have insulin resistance. Insulin resistance with associated metabolic abnormalities may be one of the causes for impaired fibrinolysis in hypertension.     

Comparison of the effects of pioglitazone and voglibose on circulating total and high-molecular-weight adiponectin, and on two fibrinolysis inhibitors, in patients with Type 2 diabetes.

BACKGROUND: To investigate short-term effects of pioglitazone and voglibose on serum concentrations of both total and high-molecular-weight (HMW) adiponectin measured with a novel sandwich enzyme-linked immunosorbent assay (ELISA) ,and on plasma fibrinolysis indicators, in Type 2 diabetic patients with inadequate glycaemic control on sulphonylureas. METHODS: Thirty-four diabetic patients were randomized to receive pioglitazone or voglibose treatment for 12 weeks, after which serum HMW adiponectin was measured. Plasma plasminogen activator inhibitor (PAI) 1 and thrombin-activatable fibrinolysis inhibitor (TAFI), a recently identified inhibitor of fibrinolysis, were measured as fibrinolysis inhibitors. RESULTS: At baseline, serum HMW adiponectin correlated negatively with plasma TAFI in all patients with Type 2 diabetes (r = -0.367, P = 0.0423). Both groups showed similar improvements in glycaemic control. Serum total and HMW adiponectin increased in patients treated with pioglitazone, but did not change in patients treated with voglibose. The HMW : total adiponectin ratio increased significantly after treatment with pioglitazone (P = 0.0004). The change in HbA(1c) correlated negatively with changes in serum HMW adiponectin in patients treated with pioglitazone (r = -0.694, P = 0.0034). Plasma PAI-1 and TAFI did not change with pioglitazone treatment. CONCLUSION: Increased serum HMW adiponectin may contribute to the improvement in glycaemic control after pioglitazone treatment. Plasma PAI-1 and TAFI were unchanged by either drug.     

高血压病人纤维蛋白原水平及纤溶系统功能研究

为了解高血压病人的血栓形成倾向,我们随机选取了４１例高血压病人及３４例正常血压者,分别观察了他们的纤维蛋白原及血浆组织型纤溶酶原激活物（ｔＰＡ）抗原及纤溶酶原激活物抑制物－１（ＰＡＩ－１）的含量。结果表明,高血压病人血浆纤维蛋白原水平无明显变化,但ｔＰＡ抗原含量减少,ＰＡＩ－１的水平增加。提示高血压病人存在内源性纤溶功能受损     

Glycaemic Control,Smoking Habits and Diabetes Duration Affect the Extrinsic Fibrinolytic System in Type I Diabetic Patients but Microangiopathy Does Not

ABSTRACT The fibrinolytic system was studied in 43 type I diabetic patients with long duration of the disease, with or without evidence of microangiopathy, and in 26 control subjects. There were positive and independent correlations between tissue plasminogen activator (tPA) activity after venous occlusion and HbA_lc, and between triglycerides and plasminogen activator inhibitor (PAI-1) and tPA antigen concentrations before and after venous occlusion. The tPA activities both at rest and after venous occlusion were higher in the patients. There were no differences with regard to sex, hypertension or nephropathy for the levels of fibrinolytic variables in these patients. Subjects with retinopathy did not differ from those without retinopathy. Diabetes duration showed a significant negative association with tPA activity in multivariate regression analysis. Tobacco-smoking diabetics, as compared to non-smoking, had an increased tPA antigen release at venous occlusion, but also higher PAI-1 levels and reduced specific activity of the tPA protein. When assessed with the new specific assays now available, the fibrinolytic parameters appear to be specific indicators of endothelial dysfunction related to smoking and to degree of glycaemic control in type I diabetic subjects.     

Different metabolic correlations of thrombin-activatable fibrinolysis inhibitor and plasminogen activator inhibitor-1 in non-obese type 2 diabetic patients

We investigated the plasma levels of thrombin-activatable fibrinolysis inhibitor (TAFI), plasminogen activator inhibitor-1 (PAI-1) and their relation with clinical and metabolic parameters in non-obese type 2 diabetic patients. The plasma levels of TAFI and PAI-1 were evaluated in 47 non-obese type 2 diabetic patients and 31 normal subjects. The intra-abdominal visceral and subcutaneous fat areas were measured by computed tomography (CT). The degree of insulin resistance was evaluated by the euglycemic-hyperinsulinemic clamp technique using artificial pancreas. The plasma levels of TAFI (169.0+/-108.8% versus 103.7+/-52.3%; p<0.001, mean+/-S.D.) and PAI-1 (82.7+/-54.5ng/ml versus 52.9+/-51.7ng/ml; p<0.05) were significantly higher in non-obese type 2 diabetic patients than in normal subjects. Univariate analysis showed that the plasma TAFI levels are significantly and inversely correlated with the glucose infusion rate (GIR) (r=-0.42, p<0.005) in all diabetic patients. Moreover, the plasma levels of TAFI were significantly correlated with fasting plasma glucose levels (r=0.47, p<0.001) and HbA(1c) (r=0.38, p<0.005) in all subjects. The plasma levels of PAI-1 were significantly and proportionally correlated with the visceral fat area (r=0.42, p<0.005) and body mass index (r=0.33, p<0.05). There was no significant correlation between plasma levels of TAFI and PAI-1 (r=0.04). These results show that the plasma levels of TAFI and PAI-1 differently correlate with insulin resistance and visceral fat accumulation, suggesting that different factors are implicated in the plasma elevation of TAFI and PAI-1 in non-obese type 2 diabetes mellitus.     

Increased PAI-1 and tPA antigen levels are reduced with metformin therapy in HIV-infected patients with fat redistribution and insulin resistance

Cardiovascular disease (CVD) risk associated with fat redistribution seen among HIV-infected individuals remains unknown, but may be increased due to hyperlipidemia, hyperinsulinemia, increased visceral adiposity, and a prothrombotic state associated with these metabolic abnormalities. In this study we characterized plasminogen activator inhibitor-1 (PAI-1) and tissue-type plasminogen activator (tPA) antigen levels, markers of fibrinolysis and increased CVD risk, in HIV lipodystrophic patients compared to controls. Furthermore, we investigated the effect of treatment with metformin on PAI-1 and tPA antigen levels in patients with HIV-associated fat redistribution. Eighty-six patients (age 43 +/- 1 yr, BMI 26.1 +/- 0.5 kg/m(2)) with HIV and fat redistribution were compared to 258 age- and BMI-matched subjects from the Framingham Offspring study. In addition, 25 HIV-infected patients with fat redistribution and fasting insulin >15 microU/mL [104 pmol/L] or impaired glucose tolerance, but without diabetes mellitus were enrolled in a placebo-controlled treatment study of metformin 500 mg twice daily. PAI-1 and tPA antigen levels were significantly increased in patients with HIV related fat redistribution compared to Framingham control subjects (46.1 +/- 4 vs 18.9 +/- 0.9 microg/L PAI-1, 16.6 +/- 0.8 vs. 8.0 +/- 0.3 microg/L tPA, P = 0.0001). Among patients with HIV infection, a multivariate regression analysis including age, sex, waist-to-hip ratio, BMI, smoking status, protease inhibitor use and insulin area under the curve (AUC), found gender and insulin AUC were significant predictors of tPA antigen. Twelve weeks of metformin treatment resulted in decreased tPA antigen levels (-1.9 +/- 1.4 vs +1.4 +/- 1.0 microg/L in the placebo-treated group P = 0.02). Similarly, metformin resulted in improvement in PAI-1 levels (-8.7 +/- 2.3 vs +1.7 +/- 2.9 microg/L, P = 0.03). Change in insulin AUC correlated significantly with change in tPA antigen (r = 0.43, P = 0.03). PAI-1 and tPA antigen, markers of impaired fibrinolysis and increased CVD risk, are increased in association with hyperinsulinemia in patients with HIV and fat redistribution. Metformin reduces PAI-1 and tPA antigen concentrations in these patients and may ultimately improve associated CVD risk.     

Impaired fibrinolytic compensation for hypercoagulability in obese patients with type 2 diabetes: association with increased plasminogen activator inhibitor-1

In patients with type 2 diabetes, fibrinolysis is considered impaired by increased plasma concentrations of plasminogen activator inhibitor (PAI)-1. However, several investigators found both coagulation and fibrinolysis to be activated in these patients. We further characterized the balance between coagulation and fibrinolysis in lean and obese patients with type 2 diabetes. We studied 112 type 2 diabetic patients (66 lean, 46 obese) and 69 age-matched healthy subjects (46 lean, 23 obese). We measured plasma concentrations of fibrinogen and prothrombin F1+2 (F1+2) as indicating coagulation activity and plasmin-antiplasmin complex (PAP) and D dimer as indicating fibrinolytic activity. Plasma PAI-1 concentrations also were determined. Plasma concentrations of F1+2, PAP, D dimer, and PAI-1 were higher in diabetic patients than in control subjects. Plasma fibrinogen and F1+2 were similar between lean and obese diabetic patients, but plasma PAP and D dimer were significantly lower in obese than lean diabetic patients (P <.0001, P =.0194, respectively). By multivariate analysis, plasma PAI-1 and body mass index (BMI) were independent factors in diabetic patients predicting PAP, while BMI and glycosylated hemoglobin (HbA(1c)) independently predicted D dimer. Plasma PAI-1 concentrations were significantly higher in obese than lean diabetic patients (P <.0001). In conclusions, both coagulation and fibrinolytic systems are enhanced in lean and obese type 2 diabetic patients compared with healthy subjects. Although the degree of activation of coagulation was similar between lean and obese diabetic patients, the fibrinolytic activity was lower in obese than lean patients. Fibrinolytic compensation for hypercoagulation is incomplete in obese patients with type 2 diabetes, partly because of elevated PAI-1 in the blood.     

氯沙坦对原发性高血压患者纤溶功能的影响

目的观察氯沙坦对原发性高血压(EH)患者纤溶功能的影响。方法观察34例EH患者应用氯沙坦治疗4周后收缩压(SBP)、舒张压(DBP)、心率、血浆组织型纤溶酶原激活物(t-PA)、内皮细胞型纤溶酶原激活物抑制剂(PAI-1)水平的变化,并与30例健康人作比较。结果治疗前EH患者血浆t-PA水平明显低于对照组,而PAI-1水平明显高于对照组(均P<0.01)。氯沙坦治疗4周后,血压明显下降,心率无明显变化,血浆t-PA水平增加,但无统计学意义,而PAI-1水平明显降低,t-PA/PAI-1比值升高(均P<0.01)。结论EH患者存在着内源性纤溶功能紊乱,氯沙坦可以改善EH患者的纤溶功能。     

氯沙坦和阿替洛尔对高血压患者纤溶系统及血浆血管性血友病因子的作用比较

目的比较血管紧张素受体拮抗剂(ARB)氯沙坦和β受体阻滞剂阿替洛尔对原发性高血压患者纤溶系统及血浆血管性血友病因子(vWF)的影响。方法轻中度原发性高血压患者60例随机分成氯沙坦组和阿替洛尔组(每组30例),分别给予氯沙坦50mg/(次.d)或阿替洛尔50mg/(次.d),共治疗8周。每4周随访1次,4周时血压如不达标(BP<140/90mmHg)则加用双氢克尿噻12.5mg/(次.d)。治疗前后行血浆组织型纤溶酶原激活物(tPA)及纤溶酶原激活物抑制剂1(PAI-1)检测,并计算PAI-1/tPA作为纤溶参数,同时测定血浆vWF的含量。结果两组的基线血压等一般情况具有可比性。治疗4周及8周时两组血压均较治疗前显著下降,组间比较无差异。同治疗前相比,氯沙坦组治疗8周时血浆PAI-1和vWF水平下降(P值分别<0.05及<0.01),PAI-1/tPA也有显著下降(P<0.05),而tPA则无显著变化(P>0.05);阿替洛尔组治疗8周时血浆PAI-1和vWF水平及PAI-1/tPA均无显著变化,而tPA则有所上升(P<0.05)。治疗后血浆vWF两组间比较,差异有非常显著意义。结论氯沙坦治疗能改善原发性高血压患者的纤溶系统并降低血浆vWF,而阿替洛尔则未见有此作用。     

Enhancement of fibrinolysis in poorly controlled, hospitalized type 2 diabetic patients by short-term metabolic control: association with a decrease in plasminogen activator inhibitor 1.

Impaired fibrinolysis in type 2 diabetes may be caused by an increased plasma concentration of plasminogen activator inhibitor 1 (PAI-1), although the effects of short-term hypoglycemic therapy on fibrinolytic activity are poorly understood. This study investigated the effects of metabolic improvement on fibrinolysis activity and plasma concentrations of PAI-1 in poorly controlled, hospitalized type 2 diabetic patients. Forty-eight poorly controlled type 2 diabetic patients were studied; 26 were subsequently treated with sulfonylurea (SU) and 22 with insulin. The plasma concentrations of plasmin-alpha2-antiplasmin (PAP), a measure of fibrinolytic activity, plasma PAI-1, and fasting triglycerides and glucoses were measured at the beginning and the end of hospitalization. The body mass index and fasting triglyceride decreased significantly after treatment (p < 0.0001). The plasma concentration of PAP increased significantly (p < 0.01), and the plasma PAI-1 decreased by 50% after treatment. There was an inverse correlation between the changes in the plasma concentrations of PAP and PAI-1 (r= - 0.36, p = 0.023). Treatment with SU or insulin showed an increase in plasma PAP with a concomitant decrease in the plasma PAI-1 with equivalent glycemic control. In poorly controlled type 2 diabetic patients, the plasma PAP concentration can be significantly increased and the plasma PAI-1 antigen significantly reduced, even with short-term metabolic improvements including weight reduction, a better lipid profile, and tighter glycemic control with either SU or insulin therapy, and that enhanced fibrinolysis may be mediated partly through a decrease in the plasma PAI-1 after metabolic control.     

Differential regulation by troglitazone of plasminogen activator inhibitor type 1 in human hepatic and vascular cells

Troglitazone, a novel oral insulin sensitizer, normalizes increased plasma activity of plasminogen activator inhibitor type 1 (PAI-1) in hyperinsulinemic patients such as women with polycystic ovary syndrome and patients with type 2 diabetes mellitus. However, underlying mechanisms have not yet been fully elucidated. Human hepatic and vascular cells, the main sources of circulating PAI-1, were studied in cell culture. In human hepatic cells, PAI-1 accumulated in conditioned medium by 23% within 24 h after exposure to 3 microg/mL troglitazone (P = 0.001). The accumulation depended on the concentration of troglitazone, but not that of insulin (known to stimulate PAI-1 synthesis). By contrast, in human aortic smooth muscle cells, 3 microg/mL troglitazone decreased basal PAI-1 expression by 23% (P = 0.037) and decreased transforming growth factor-beta-induced expression by 34% (P = 0.026). Concomitant insulin had no effect. Tissue-type plasminogen activator was decreased by 38% (P = 0.002). In human endothelial cells, PAI-1 was diminished by 32% (P < 0.001), whereas tissue-type plasminogen activator was unaffected. The results suggest that the reduction in plasma activity of PAI-1 induced by troglitazone in patients may reflect both directly mediated diminution of its elaboration from vessel walls and indirectly mediated reduction of its hepatic synthesis secondary to attenuation of hyperinsulinemia (known to increase the hepatic synthesis of PAI-1).     

Hypofibrinolysis in patients with hypercoagulability: The roles of urokinase and of plasminogen activator inhibitor

The prevalence of abnormalities of fibrinolysis in patients with venous thromboembolism is as yet unknown. Defined abnormalities include congenital dysfunction and deficiency of plasminogen, and probably impaired plasminogen activation secondary to elevated levels of plasminogen activator inhibitor type 1 (PAI-1) or to impaired release of tissue plasminogen activator (tPA). In this preliminary study, we analyzed plasma samples from 21 patients for whom an investigation for possible thrombophilia was requested. Twenty of the patients had venous thromboembolism, and one had arterial thrombosis at an early age. Two patients had deficiency of protein C or protein S, but no other recognized biochemical disturbances related to thrombophilia were identified. Patient samples and plasma from 25 normal controls were assayed for tPA activity, PAI-1 activity, and urokinase (uPA) activity and antigen. tPA activity and antigen were not significantly different in patients than in controls. PAI-1 activity was significantly greater in patients (P < 0.0001). uPA activity was not different in the two groups. However, uPA antigen was significantly reduced in patients compared to controls (P = 0.001). These data suggest that hypofibrinolysis leading to a risk of thrombosis may be caused not only by elevated PAI-1 activity but also by reduced total uPA concentration. © 1993 Wiley-Liss, Inc.     

西拉普利对心房颤动犬内皮细胞功能及纤溶系统的影响

目的研究血管紧张素转换酶抑制剂西拉普利对心房颤动(房颤)犬内皮功能和纤溶系统的影响。方法应用埋藏式高频心脏起搏器快速起搏心房建立房颤犬动物模型。实验分为未起搏组、单纯起搏组和起搏 西拉普利组。采用ISO-NOP3005一氧化氮(NO)敏感电极测定心内膜NO含量;酶联免疫吸附双抗体夹心法测定血浆血管性血友病因子水平;Westernblot定量分析心房心肌纤溶酶原激活剂抑制物-1(PAI-1)和组织型纤溶酶原激活剂(tPA)蛋白表达;同时免疫组化检测蛋白表达位置。血浆PAI-1和tPA含量采用酶联免疫吸附双抗体夹心法测定。结果西拉普利能显增加房颤犬心内膜NO合成,降低血浆血管性血友病因子水平,同时显减少心房肌PAI-1蛋白表达和血浆PAI-1含量,增加心房肌tPA蛋白表达和血浆含量。结论西拉普利能明显改善房颤犬内皮细胞功能,恢复纤溶系统平衡,可能对房颤的血栓前状态有益。     

Anti-inflammatory effects of troglitazone in nondiabetic obese subjects independent of changes in insulin sensitivity

BACKGROUND: Obesity is characterised by insulin resistance and by elevated levels of proinflammatory markers. We investigated whether, in the absence of changes in glucose, thiazolidinediones (TZDs) have anti-inflammatory effects and whether improvement of insulin sensitivity correlates with suppression of inflammatory markers. METHODS: We performed a randomised double-blind placebo-controlled crossover study with troglitazone (400 mg daily for eight weeks) in 15 normoglycaemic obese subjects. We measured plasma high-sensitivity C-reactive protein (hsCRP), interleukin-6 (IL-6), leptin, tissue-type plasminogen activator (tPA), plasminogen activator inhibitor-1 (PAI-1) and tumour necrosis factor-alpha (TNF-alpha) after each of the two treatment periods and in 13 age- and sex-matched lean individuals. RESULTS: Obese subjects were insulin resistant (decreased glucose infusion rate (GIR) during euglycaemic hyperinsulinaemic clamp) and had higher plasma levels of hsCRP, IL-6, leptin, tPA, and PAI-1 compared with lean subjects. TNF-alpha also tended to be higher. Troglitazone improved insulin sensitivity (mean increase in whole body glucose uptake 23.1 +/- 10.5% (p = 0.047)) and normalised plasma concentrations of hsCRP, tPA and TNF-alpha, whereas it did not significantly change IL-6, leptin and PAI-1. Changes in GIR did not correlate with changes in inflammatory markers. CONCLUSION: Troglitazone induces suppression of some of the inflammatory markers that are elevated in normoglycaemic obese subjects. The suppression of inflammatory markers, however, does not correlate with improvement in insulin sensitivity, suggesting involvement of partially differential mechanisms in these effects of TZDs.     

Plasma levels of tissue plasminogen activator/plasminogen activator inhibitor-1 complex and von Willebrand factor are significant risk markers for recurrent myocardial infarction in the Stockholm Heart Epidemiology Program (SHEEP) study

An impaired fibrinolytic function due to elevated plasma levels of plasminogen activator inhibitor (PAI)-1 activity or tissue plasminogen activator (tPA) antigen is correlated with the development of myocardial infarction (MI) in patients with manifest coronary heart disease. Recently, methods for determining the specific tPA/inhibitor complexes constituting tPA antigen in plasma have become available. In the Stockholm Heart Epidemiology Program (SHEEP) study, 86 of 1212 MI patients, subjected to blood sampling in a metabolically stable period, suffered reinfarction before the end of 1996. These individuals have been compared with an approximately equal number of matched MI patients without recurrence and a group of matched healthy control subjects regarding the plasma concentrations of some hemostatic factors. The hemostatic compounds studied (fibrinogen, von Willebrand factor, tPA antigen, PAI-1, and the tPA/PAI-1 complex) were typically higher in the groups (men and women) with recurrence of MI compared with those without. The plasma concentrations were also typically higher in the pooled groups of patients compared with the groups of healthy control subjects. The largest between-group differences were found for the plasma tPA/PAI-1 complex. The crude odds ratio for reinfarction associated with higher concentration (>/=75th percentile among the control subjects) of tPA/PAI-1 was 1.8 (95% CI 1.1 to 3.1); the corresponding crude odds ratio for von Willebrand factor was 2.3 (1. 3 to 4.0). The tPA/PAI-1 complex correlated strongly with PAI-1 and tPA antigen in all groups and with serum triglycerides and body mass index in all groups except for women with reinfarction. An increased plasma level of tPA/PAI-1 complex is a novel risk marker for recurrent MI in men and women. Most likely, increased plasma levels of tPA/PAI-1 complex reflect impaired fibrinolysis, because the correlation with PAI-1 is strong. Further support is obtained indicating that the plasma concentration of von Willebrand factor is also an important risk marker for recurrent MI.     

持续气道正压通气对OSAHS患者血管内皮细胞及纤溶系统的影响

为探讨经鼻持续气道正压通气（nCPAP)治疗前后阻塞性睡眠呼吸暂停低通气综合征（OSAHS）患者血管内皮细胞及纤溶系统的变化及临床意义，选择年龄，性别，体重指数（BMI）无明显差异的OSAHS患者38例和健康者对照组32例，用多导睡眠呼吸监测仪进行监测，以凝固法测定纤维蛋白原（Fg），发色底物法测组织纤溶酶原激活物活性（tPA：A）、纤溶酶原激活物抑制物－1活性（PAI－1：A），酶联免疫法测vonWillebrand因子（vWF)、组织纤溶酶原激活物抗原（tPA:Ag）、纤溶酶原含量（PLg:Ag)和纤溶酶原激活物抑制物－1含量（PAI－1：Ag）。结果OSAHS组与对照组比较，vWF,Fg,tPA:Ag、PAI－1：A明显升高（P分别＜0．01，0．001，0．001，0．01），PLg:Ag、tPA:A、tPA:Ag、最低血氧饱和度（SaO2low)明显降低（P分别＜0．01，0．001，0．001，0．01).nCPAP治疗后与治疗前比较，vWF,Fg,PAI-1:Ag,PAI-1:A明显降低（P分别＜0．05，0．01，0．01，0．01），PLg:Ag,tPA:A,tPA:Ag，最低SaO2明显升高（P分别＜0．05，0．001，0．001，0．01）。提示OSAHS患者血管内皮细胞损伤，凝血功能增强，纤溶系统功能减弱;nCPAP治疗能部分纠正各指标的异常。     

Impact of diabetes-associated lipoproteins on generation of fibrinolytic regulators from vascular endothelial cells.

Increased thrombotic tendency and decreased fibrinolytic activity have been frequently found in patients with diabetes mellitus (DM). Previous studies by our group indicated that nonenzymatically glycated low density lipoprotein (LDL) increased plasminogen activator inhibitor-1 (PAI-1) production and decreased the generation of tissue plasminogen activator (tPA) from cultured human umbilical vein endothelial cells (HUVEC). The present study demonstrates that plasma levels of PAI-1 or PAI-1/tPA were significantly increased in patients with type 1 (n = 10) and type 2 DM (n = 14) compared with those in healthy controls (n = 10; P < 0.05 or 0.01). LDL from patients with type 1 or type 2 DM, and very low density lipoprotein (VLDL) from patients with type 2 DM induced significantly greater increases in the release of PAI-1 and more profound reduction in tPA generation from HUVEC compared with corresponding lipoproteins from healthy controls (P < 0.05 or 0.01). HDL from diabetic patients did not significantly alter the generation of PAI-1 or tPA from endothelial cells (EC) compared with HDL from controls. Comparable effects of lipoproteins from DM patients on the generation of PAI-1 and tPA were found in human coronary artery EC. LDL and VLDL from patients with type 2 DM enhanced the activation of PAI-1 promoter (-1528/+55)/luciferase reporter gene transiently transfected in HUVEC (P < 0.01). The results of the present study suggest that LDL and VLDL from patients with DM reduce the generation of tPA and increase PAI-1 production through the activation of the PAI-1 promoter in vascular EC.     

Some parameters of hemostasis and fibrinolysis in diabetic patients

The aim of our study was to estimate selected parameters of hemostasis and fibrinolysis in diabetic patients with vascular complications and obesity. The investigation was carried out in 23 type 1 diabetic subjects aged 17-56 ys, in 25 type 2 diabetic patients aged 41-69 ys and in 38 healthy persons: 16 "young"--aged 32.5 +/- 13.2 ys and 22 "old"--aged 56.2 +/- 9.4 ys. The following parameters were determined: glycaemia, HbA1c, blood level fibrinogen, euglobulin clot lysis time, plasminogen activator inhibitor (PAI-1) activity, microalbuminuria, triglyceride, total, HDL- and LDL-cholesterol concentration. Plasma fibrinogen level was elevated in type 2 diabetic subjects, and the highest concentrations were noted in patients with retinopathy or arterial hypertension, in overweight persons and--surprisingly--in type 1 diabetic subjects with nephropathy and coronary vascular disease (CVD). There were also positive correlations between fibrinogen level and systolic blood pressure (r = 0.3413, p < 0.02), diastolic blood pressure (r = 0.3809, p < 0.002) and microalbuminuria (r = 0.3552, p < 0.05). The mean euglobulin clot lysis time was prolonged in type II diabetics in comparison to the control group, especially in obese subjects. The highest activity of PAI-1 was found in overweight controls (28.87 +/- 6.24 Au/ml, p < 0.002). PAI-1 activity was also slightly increased in type 1 diabetic patients, especially with the symptoms of diabetic neuropathy, nephropathy or CHD, in comparison to the other groups. Our results seem to confirm the disturbed balance between coagulation and fibrinolysis--towards and increased risk of a prothrombotic state --in both--obese and diabetic patients--especially with advanced vascular complications.     

The Role of the Fibrinolytic System in Corneal Angiogenesis

The plasminogen activation system has been implicated in angiogenesis and angiogenesis-dependent diseases such as cancer, atherosclerosis and ocular diseases. The identification and development of inhibitors of angiogenesis offer new possibilities for the treatment of these diseases. To clarify the role of proteins involved in the regulation of fibrinolysis during corneal angiogenesis, we have studied corneal vessel formation in mice deficient for urokinase-type plasminogen activator (uPA), tissue-type plasminogen activator (tPA), plasminogen, plasminogen activator inhibitor-1 (PAI-1) and thrombin-activatable fibrinolysis inhibitor (TAFI). Our results corroborate earlier findings that angiogenesis in the mouse cornea is dependent on PAI-1 and plasminogen. The absence of tPA, uPA or TAFI did not affect the formation of new vessels in the cornea.     

Tissue-type plasminogen activator and its inhibitor (PAI-1) in plasma in cases of non-insulin-dependent diabetes mellitus (NIDDM)

Parameters of fibrinolysis, including plasminogen, alpha 2 plasmin-inhibitor (alpha 2 PI), tissue-type plasminogen activator (t-PA) and plasminogen activator inhibitor-1 (PAI-1) antigens, and fibrinogen were assayed in 53 patients (28 women and 27 men; mean age: 64 years, age range: 32-87 years) with non-insulin-dependent diabetes mellitus (NIDDM). The control group was similarly aged (mean age: 60.4 years, age range: 38-81). The levels of t-PA and t-PA/PAI-1 ratio of the diabetic group (mean +/- SD; 9.8 +/- 4.3 ng/ml, 0.94 +/- 0.47, respectively) were significantly higher than that of the control group (5.5 +/- 2.5 ng/ml, 0.51 +/- 0.23, respectively). The increased levels of t-PA antigen and t-PA/PAI-1 ratio in diabetics mean that free t-PA has been released. However, there was no significant difference in the level of PAI-1 between the diabetic group (12.9 +/- 6.4 ng/ml) and the control group (12.1 +/- 5.6 ng/ml). Levels of fibrinogen, plasminogen and alpha 2 PI in plasma were not different in the two groups. Duration of the disease, levels of glycosylated hemoglobin, differences in treatment and presense of diabetic nephropathy or retinopathy did not affect the fibrinolytic parameters. The levels of fibrinogen was higher in those with nephropathy than in the diabetics without nephropathy and retinopathy (p less than 0.05). There were no significant differences in the levels of t-PA, t-PA/PAI-1 ratio and PAI-1 between younger (less than 65 years) and older (65 years or more) subjects, in either the control or diabetic groups.(ABSTRACT TRUNCATED AT 250 WORDS)