Effect of activated human protein C on disseminated intravascular coagulation induced by lipopolysaccharide in rats

Protein C is the zymogen of an anticoagulant serine protease and is converted to its active form (activated protein C: APC) by thrombin in the presence of thrombomodulin. APC plays an important role in regulating coagulation and fibrinolysis by inactivating not only blood coagulation factors Va and VIIIa but also type-1 plasminogen activator inhibitor (PAI-1). The aim of the present study was to examine the effect of a human APC product (designated as CTC-111), compared with that of heparin, on the disseminated intravascular coagulation (DIC) induced by lipopolysaccharide (LPS) in rats. LPS (1 mg/kg/h) infusion was performed through a femoral vein for 4 h. One-fifth amount of the total dosage of CTC-111 or heparin was injected into the other femoral vein, followed by a 4-h infusion of the remainder. Both CTC-111 (10,000-100,000 U/kg) and heparin (400-800 IU/kg) inhibited the decrease in platelet count and fibrinogen level equally. The prolonged activated partial thromboplastin time and prothrombin time observed in DIC rats were further elongated in both CTC-111- and heparin-treated rats. But, this prolongation was less in CTC-111-treated rats than in the heparin-treated ones. Heparin inhibited the increase in fibrin and fibrinogen degradation products more prominently than CTC-111. On the other hand, CTC-111 strongly inhibited the increase in PAI-1 activity but heparin did not. These results suggest that CTC-111 may enhance fibrinolysis through its direct inhibitory effect on PAI-1. The parameters for liver or renal damage, i.e., plasma glutamic-oxaloacetic transaminase (GOT), glutamic-pyruvic transaminase (GPT), creatinine (Cre) and blood urea nitrogen (BUN), were significantly increased by LPS infusion. Both CTC-111 (100,000 U/kg) and heparin (800 IU/kg) decreased the increase in GOT and GPT levels significantly, whereas neither affected the increase in Cre or BUN. From these results, the activation of the blood coagulation system might partially contribute to the progression of liver damage caused by LPS, and might be less involved in the progression of renal damage in this model. In conclusion, CTC-111 showed both anticoagulant and profibrinolytic activity in the LPS-induced DIC model without excessive prolongation of coagulation time. From these results, CTC-111 is expected to be a useful remedy for DIC without the risk of bleeding.     

Antithrombotic activities of sulforaphane via inhibiting platelet aggregation and FIIa/FXa

Sulforaphane (SFN), a natural isothiocyanate that is present in cruciferous vegetables such as broccoli and cabbage, is effective in preventing carcinogenesis, diabetes and inflammatory responses. Here, the anticoagulant activities of SFN were examined by monitoring activated partial thromboplastin time (aPTT), prothrombin time, and the activities of thrombin (Factor IIa, FIIa) and activated factor X (FXa). And, the effects of SFN on expression of plasminogen activator inhibitor type 1 (PAI-1) and tissue-type plasminogen activator (t-PA) were evaluated in tumor necrosis factor-α activated human umbilical vein endothelial cells (HUVECs). Treatment with SFN resulted in prolonged aPTT and PT and inhibition of the activities of thrombin and FXa, as well as inhibited production of thrombin and FXa in HUVECs. In addition, SFN inhibited thrombin-catalyzed fibrin polymerization and platelet aggregation. SFN also elicited anticoagulant effects in mice. In addition, treatment with SFN resulted in significant reduction of the PAI-1 to t-PA ratio. Collectively, SFN possesses antithrombotic activities and offers a basis for development of a novel anticoagulant.     

Angiotensin II and IV stimulate expression and release of plasminogen activator inhibitor-1 in cultured human coronary artery endothelial cells

There is increasing evidence that angiotensin II influences thrombogenesis by regulating the expression of plasminogen activator inhibitor-1 (PAI-1). In this study, the effects of angiotensin II and its receptors on the expression and release of PAI-1 and tissue-type plasminogen activator (t-PA) were examined in human coronary artery endothelial cells (HCAECs). As control, cells were treated with angiotensin IV. HCAECs incubated with angiotensin II increased the expression of PAI-1 mRNA in a concentration (10-9-10-5 M)- and time (6-24 h)-dependent manner. PAI-1 protein release was also increased in the culture medium of HCAECs treated with angiotensin II. The effects of angiotensin II (10-6 M) were blocked completely by the AT1 receptor blocker losartan (10-6 M) but not by the AT2 receptor blocker PD123319 (10-6 M). Angiotensin II pretreatment also slightly, but significantly, increased t-PA mRNA expression. This effect of angiotensin II on t-PA mRNA was blocked by losartan but not by PD123319. HCAECS treated with angiotensin II revealed large amounts of the lipid peroxidation product, malonaldehyde (MDA). The effects of angiotensin II on PAI-1 expression and MDA release were blocked by pretreatment of cells with alpha-tocopherol (10-5 M). In control experiments, treatment of HCAECs with angiotensin IV markedly increased PAI-1 mRNA expression and protein release. This effect of angiotensin IV was blocked by the AT4 receptor blocker divalinal (10-6 M). These observations indicate that AT1 receptor activation plays an important role in the stimulation of PAI-1 expression and release in response to angiotensin II. Upregulation of t-PA gene may reflect autoregulation in response to PAI-1 release. Angiotensin II-mediated activation of oxidation pathways may relate to uupregulation of PAI-1. This study also confirms that angiotensin IV upregulates PAI-1 expression in HCAECs.     

Anti-thrombotic effect of activated protein C

Protein C (PC) is an important anticoagulant protein in blood and converted to its active form, activated protein C (APC), by thrombin bound with thrombomodulin. APC exhibits an anticoagulant effect by the inactivation of FV a and FVIII a. In addition, APC exerts a profibrinolytic effect by inactivation of PAI-1 and inhibition of TAFI activation. APC is strongly anti-thrombotic because of its anticoagulant and profibrinolytic effect. APC has gamma-carboxyglutamic acid residues that bind to acidic phospholipids expressed on activated platelet or injured endothelial cells. Thus APC works only at the site where clots are formed and has a weak effect in primary hemostasis; this means that the use of APC is expected not to have any hemorrhagic risk. In both DIC animal models and clinical studies, we confirmed safer amelioration by APC than heparin. Recently, a specific receptor for PC/APC was found on endothelial cell membrane and anti-inflammatory effects of APC were also reported. Thus APC is thought to play an important regulatory role in blood coagulation, fibrinolysis and inflammation, especially in thrombotic diseases.     

三七皂苷Rg1对t-PA和PAI-1水平的影响

目的探讨三七皂苷Rg1对组织型纤溶酶原激活物(t-PA)和纤溶酶原激活物抑制物(PAI-1)水平的影响及其作用机制。方法运用发色底物法测定三七皂苷-Rg1在家兔体内、外对血浆纤溶酶原激活物(t-PA)和血浆或血小板释放的纤溶酶原激活物抑制物(PAI-1)水平的影响。结果三七皂苷-Rg1在体外能抑制血浆PAI-1活性,提高血浆t-PA活性,其作用强度呈现出剂量依赖性;静脉内给药显示:三七皂苷-Rg1 30、60、120和240 mg.kg-1组能降低血浆或血小板释放的纤溶酶原激活物抑制物(PAI-1)水平,增强血浆t-PA活性,而且本品还能降低激活的血小板所释放的PAI-1水平。结论三七皂苷Rg1能够有效对抗由于PAI-1活性增高和t-PA活性降低所引起的血栓,这可能是其具有抗血栓作用的有效机制之一。     

糖尿病伴血管病变时血管内皮功能、纤溶活性及血小板活化的变化

目的：观察DM患者无（A组）与有（B组）血管病变时的血管内皮功能、纤溶活性及血小板活化状态的变化。方法：vWF用免疫电泳法,TMT GMP－140用ELISA法,t-PA和PAI－1用发色底物显色法,PAgT比浊法。结果：（1）vWF:Ag、TM、PAI－1和GMP－1404项指标,DM及其两个亚组都高于对照组,B组高于A组。(2)t-PA,B组高于对照组和A组。（3）PAgT,仅见B组高于对照组,以上的差异均有显著性意义（P＜0．05或P＜0．01）。结论：（1）DM早期即有血管内皮细胞损伤,发生血管病变则增高更为显著。（2）DM凝血与纤溶调节处于较高水平,PAI－1相对升高,系诱发血栓形成的危险因素。（3）血浆GMP－140为反映血小板活化敏感的指标。     

Paeoniflorin alleviates lipopolysaccharide-induced disseminated intravascular coagulation by inhibiting inflammation and coagulation activation

Lipopolysaccharide (LPS) is a toxic component of the outer membrane of gram-negative bacteria that can activate the blood coagulation system, leading to disseminated intravascular coagulation (DIC). DIC is a syndrome characterized by thromboembolism and multiple organ failure. Herein, the beneficial effect of paeoniflorin (PF) on the alleviation of LPS-induced DIC was investigated with an experimental DIC mouse model. Briefly, mice were randomly divided into the following six groups: (1) control; (2) LPS; (3) heparin; (4) low-PF treatment; (5) medium-PF treatment; and (6) high-PF treatment. The histological morphology of the liver and kidney was observed, and the coagulation indicators (such as prothrombin time), function indicators (such as alanine transferase), and inflammatory factors (such as TNF-α) were detected. Additionally, an in vitro cell inflammation model using RAW 264.7 murine macrophages was established. Activation of the nuclear factor kappa B (NF-κB) signaling pathway and tumor necrosis factor-α (TNF-α) were determined by western blotting. Based on our findings, PF could significantly improve the histological morphology of the liver and kidney, indicating that PF protects the liver and kidney against damage induced by LPS. Additionally, PF improved the function and coagulation indicators and reduced the production of inflammatory factors. In vitro, PF inhibited the expression of TNF-α by suppressing NF-κB signaling pathway activation. Collectively, our findings support the hypothesis that PF has anti-inflammatory and anticoagulation effects for the alleviation of LPS-induced DIC. PF is thus a potential co-treatment option for DIC.     

凝血与纤溶系统水平在产妇DIC中的对比研究

目的探讨产妇弥漫性血管内凝血（disseminated intravascular coagulation,DIC）的凝血与纤溶系统水平,了解产妇DIC前后凝血与纤溶系统变化情况,提高对产妇DIC的认识。方法对驻马店市中心医院8例产妇发生DIC前后均接受凝血与纤溶系统检验方法检测,同时按照DIC诊断标准进行诊断分析。结果发生DIC的8例产妇在产前状态时,常规检查就有各种凝血时间延长,FIB降低,D-D升高。随着8例产妇DIC的发生各种凝血时间延长,FIB降低,D-D升高进一步加剧。结论产妇进行血液凝血指标检测,可及时采取相应措施,有助于防治产科意外,防止DIC的发生并及时治疗。     

Alternative treatments for disseminated intravascular coagulation

The acronym DIC is commonly interpreted as "death is coming". This pessimistic view emphasizes the deficiency of available treatment options following diagnosis of disseminated intravascular coagulation. Clinically, DIC manifests as a systemic hemorrhagic disorder associated with widespread activation and eventual exhaustion of the coagulation system, although events underlying DIC also involve effectors of inflammation. DIC can be associated with diverse conditions including sepsis and major trauma and, when identified, signifies a significant worsening in prognosis and expected mortality. Although recent clinical studies have shown that activated protein C reduces mortality in patients with severe sepsis, there is a need for further investigation and a better understanding of the underlying mechanisms.     

Tanshinone IIA protects rabbits against LPS-induced disseminated intravascular coagulation (DIC)

Aim:

To evaluate the effects of tanshinone IIA (Tan IIA), a lipophilic diterpene from the Chinese herb Salvia miltiorrhiza, on lipopolysaccharide (LPS)-induced disseminated intravascular coagulation (DIC) in rabbits.

Methods:

LPS-induced DIC model was made in adult male New Zealand rabbits by continuous intravenous infusion of LPS (0.5 mg/kg) via marginal ear vein for 6 h. The animals were simultaneously administered with Tan IIA (1, 3 and 10 mg/kg) or heparin (500 000 IU/kg) through continuous infusion via the contralateral marginal ear vein for 6 h. Before and 2 and 6 h after the start of LPS infusion, blood samples were taken for biochemical analyses.

Results:

Continuous infusion of LPS into the rabbits gradually impaired the hemostatic parameters, damaged renal and liver functions, increased the plasma TNF-α level, and led to a high mortality rate (80%). Treatment of the rabbits with Tan IIA dose-dependently attenuated the increase in activated partial thromboplastin time (APTT), prothrombin time (PT) and fibrin-fibrinogen degradation products (FDP); ameliorated the decrease in plasma levels of fibrinogen and platelets; and reversed the decline in activity of protein C and antithrombin III. Meanwhile, the treatment significantly suppressed the increase in the plasma levels of aminotransferase, creatinine and TNF-α, and led to much lower mortality (46.7% and 26.7% for the medium- and high-dose groups). Treatment of the rabbits with the high dose of heparin also effectively improved the hemostatic parameters, ameliorated liver and renal injuries, and reduced the plasma level of TNF-α, and significantly reduced the mortality (33.3%).

Conclusion:

Tan IIA exerts a protective effect against DIC in rabbits.     

The effect of nitric oxide synthase inhibition on the plasma fibrinolytic system in septic shock in rats.

1. We have investigated the effect of pretreatment of rats with nitric oxide (NO) synthase inhibitor, NG-nitro-L-arginine methyl ester (L-NAME) on the E. coli lipopolysaccharide (LPS)-induced changes in the plasma fibrinolytic system, platelet count, fibrinogen level, as well as in gross and microscopic pathophysiological changes indicative of disseminated intravascular coagulation (DIC) in rats. 2. E. coli LPS (6 mg kg-1, i.p.) produced a decrease in the levels of plasma fibrinogen and a drop in the blood platelet count 6 h after administration. The decrease in fibrinogen but not the drop in platelet count was reversed by pretreatment with L-NAME (30 mg kg-1, i.p., 24 h and 15 min before administration of LPS). 3. Pretreatment with L-NAME antagonized the LPS-induced activation of fibrinolysis as measured by changes in the euglobulin clot lysis time (ECLT) and enhanced the LPS-induced rise in the plasma level of plasminogen activator inhibitor (PAI). In animals pretreated with L-NAME there was also a marked reduction in the histological changes indicative of DIC. 4. We propose that L-NAME can act as a protective agent in LPS-induced DIC, and this protection is due to an increased generation of PAI following inhibition of NO synthase.     

Antithrombotic and profibrinolytic activities of isorhamnetin-3-O-galactoside and hyperoside

The potential anticoagulant activities of two single compounds, isorhamnetin-3-O-galactoside (IMG) and hyperoside, from Oenanthe javanica, were tested. The anticoagulant activities were investigated by measuring activated partial thromboplastin time (aPTT) and prothrombin time (PT), and the ability to inhibit production of thrombin and activated factor X (FXa) was investigated in human umbilical vein endothelial cells (HUVECs). And, the effects of the compounds on expression of plasminogen activator inhibitor type 1 (PAI-1) and tissue-type plasminogen activator (t-PA) were tested in tumor necrosis factor-(TNF)-α activated HUVECs. Treatment with IMG and hyperoside resulted in significantly prolonged aPTT and PT and inhibition of the activities of thrombin and FXa, and IMG or hyperoside inhibited production of thrombin and FXa in HUVECs. In accordance with these anticoagulant activities, both agents elicited anticoagulant effects in mouse. In addition, treatment with IMG and hyperoside resulted in inhibition of TNF-α-induced production of PAI-1, and treatment with IMG resulted in significant reduction of the PAI-1 to t-PA ratio. The anticoagulant and profibrinolytic effects of IMG were greater than those of hyperoside, indicating positive regulation of its anticoagulant function by the methoxy group of IMG. IMG and hyperoside possess antithrombotic activities and offer bases for development of a novel anticoagulant.     

Genistein has the function of alleviating and treating disseminated intravascular coagulation caused by lipopolysaccharide

Symptoms of disseminated intravascular coagulation (DIC) include thromboembolism, acute attrition bleeding and multiple organ failure. Genistein isolated from leguminous plants has been shown to be effective in oxidation resistance and tumor inhibition. The present study was designed to evaluate the therapeutic effects of genistein in DIC and preliminarily discuss the mechanisms regarding the anti-inflammatory and anticoagulant effect of genistein. Swiss mice were randomly divided into the following groups—(1) lipopolysaccharide (LPS), (2) genistein, (3) dimethyl sulfoxide (DMSO, the non-major solvent component of genistein), (4) DMSO?+?LPS, (5) saline control group, and (6) heparin control group. LPS was injected intraperitoneally in all the groups except the DMSO group and saline control group. Our results significantly showed that the morphological structure of the liver and kidneys was improved and the fiber protein deposition was decreased, with remarkable improvement of coagulation indicators, function indicators and inflammatory factors in the genistein treatment group compared with the LPS group. In vitro phosphorylated-nuclear factor kappa-light-chain-enhancer of activated B cells and interleukin-6 were obviously reduced in the genistein treatment group compared with the LPS group in RAW 264.7 murine macrophage cells. All the results suggested that genistein has the function of alleviating and treating LPS-induced DIC by anti-inflammatory and anticoagulation effects. We tentatively propose that genistein is a potential drug for auxiliary treatment of DIC.     

FeCl_3诱导的大鼠颈总动脉血栓模型血浆TXA_2、PGI_2、抗凝和纤溶活性的变化

目的探讨FeC l3诱导的大鼠动脉血栓形成模型血浆TXA2、PG I2含量及抗凝、纤溶活性的变化。方法以FeC l3外敷诱导大鼠左侧颈总动脉血栓形成,测定血浆TXA2和PG I2稳定代谢产物TXB2、6-keto-PGF1α含量及t-PA、PAI-1、PLG、AT-Ⅲ和PC活性。结果浓度为2.16 mol.L-1的FeC l3可诱导大鼠颈总动脉闭塞性血栓形成,且该模型血浆TXB2含量升高(P<0.05),6-keto-PGF1α含量降低(P<0.05);血浆t-PA和PLG活性降低(P<0.05),PAI-1活性无变化(P>0.05),t-PA/PAI-1比值降低(P<0.05);血浆AT-Ⅲ活性降低(P<0.01),PC活性轻微降低(0.10>P>0.05)。噻氯匹定可抑制FeC l3诱导的血栓形成,但对TXB2和6-keto-PGF1α无影响,表明其抗栓作用不是通过抑制血小板TXA2生成而实现的;噻氯匹定还可升高血浆t-PA活性,可能系该药通过抑制血栓形成,减少了血浆t-PA消耗所致。而该药对AT-Ⅲ和PC活性无影响。抗凝血药低分子肝素(LMWH)也可抑制血栓形成,该药对TXB2和6-keto-PGF1α无影响。LMWH可升高血浆t-PA活性和t-PA/PAI-1比值,可能与其促进血管内皮细胞释放t-PA有关。LMWH还可使该模型血浆AT-Ⅲ活性降低,这是由于LMWH与AT-Ⅲ结合而发挥其抗凝作用,从而使血浆中AT-Ⅲ消耗所致。结论FeC l3可诱导大鼠闭塞性动脉血栓形成,该模型与血小板活化和凝血系统激活有关,同时该模型存在抗凝蛋白活性降低和纤溶活性降低的病理改变。     

Antithrombotic activities of oroxylin A in vitro and in vivo

Here, the anticoagulant activities of oroxylin A (OroA), a major component of Scutellaria baicalensis Georgi, were examined by monitoring activated partial thromboplastin time (aPTT), prothrombin time (PT), and the activities of cell-based thrombin and activated factor X (FXa). Furthermore, the effects of OroA on the expressions of plasminogen activator inhibitor type 1 (PAI-1) and tissue-type plasminogen activator (t-PA) were tested in tumor necrosis factor (TNF)-α activated human umbilical vein endothelial cells (HUVECs). Treatment with OroA resulted in prolonged aPTT and PT and inhibition of the activities of thrombin and FXa, and OroA inhibited production of thrombin and FXa in HUVECs. And OroA inhibited thrombin-catalyzed fibrin polymerization and platelet aggregation. In accordance with these anticoagulant activities, OroA elicited anticoagulant effects in mouse. In addition, treatment of OroA resulted in the inhibition of TNF-α-induced production of PAI-1, and treatment with OroA resulted in the significant reduction of the PAI-1 to t-PA ratio. Collectively, OroA possess antithrombotic activities and offer bases for development of a novel anticoagulant.     

Recombinant fibrinogenase from Agkistrodon acutus venom protects against sepsis via direct degradation of fibrin and TNF-alpha

Severe sepsis remains a leading cause of death and disability because of less effective therapy available for this disease. A complex interplay between the inflammatory factors and the coagulation pathways seems to be the fundamental mechanisms for the pathogenesis of sepsis. Here we report that recombinant fibrinogenase II (rF II) from Agkistrodon acutus plasmin-independently degraded the thrombi, and inhibited inflammatory responses by direct and specific degradation of tumor necrosis factor alpha (TNF-alpha) induced by lipopolysaccharide (LPS) without showing proteolytic activities on interleukin-1 (IL-1), cluster of differentiation 68 (CD68) and some other serum proteins. We also report that rF II effectively protected against LPS induced sepsis in a rabbit model. Administration of rF II reduced hepatic and renal damage, decreased the levels of alanine aminotransferase (ALT) and blood urea nitrogen (BUN), and increased survival rate in LPS-induced sepsis rabbits. We further confirmed the rescue effect of rF II on severe sepsis in rat caecal ligation and puncture (CLP) model. Our findings suggest that rF II could effectively protect against sepsis via direct degradation of microthrombi and inflammatory factor TNF-alpha as well as provide a novel strategy to develop a single proteinase molecule for targeting the main pathological processes of this disease.     

组织型纤溶酶原激活剂突变体瑞替普酶的原核表达、活性鉴定及酶动力学

目的重组表达抗纤溶酶原激活剂抑制剂(PAI)作用的组织型纤溶酶原激活剂(t-PA)突变体(PA1 t-PA),经诱导表达、复性和纯化后进行生物学活性和酶动力学分析。方法构建pBV220-t-PA重组表达质粒,经DNA测序确认后,转化至大肠杆菌DH5α,温控诱导表达,凝胶过滤法对包涵体蛋白进行初步纯化,复性后,过刺桐胰蛋白酶抑制剂亲和层析柱纯化,酶动力学分析其活性。结果经测序t-PA突变体的DNA序列正确,表达蛋白占总菌体蛋白的30%,经纯化后纯度>95%,比活性为4.2×108 IU.g-1,t-PA突变体与PAI-1反应后其活性未受到抑制。t-PA突变体酶的米氏常数Km为0.3298μmol·L-1,最大水解速度Vmax为0.0476μmo·lmin-1.g-1。结论 t-PA突变体能够明显抵抗PAI的抑制作用,并具有良好的生物活性。     

大剂量辛伐他汀对急性心肌梗死患者纤溶活性及C-反应蛋白的早期干预作用

目的 探讨辛伐他汀对急性心肌梗死（AMI）患者血清C-反应蛋白（CRP）水平及纤溶活性的影响。方法60例AMI患者随机分为常规治疗组（30例）和阿托伐他汀治疗组（30例），20例健康人为对照组。阿托伐他汀治疗组于常规治疗基础上加用辛伐他汀40g／d，疗程为4周。两组均于治疗前和治疗结束时测定血清CRP、血清总胆固醇（TC）、甘油三酯（TG）、高密度脂蛋白-胆固醇（HDL—C）、低密度脂蛋白-胆固醇（LDL—C）、组织型纤溶酶原激活物（t-PA）和纤溶酶原激活物抑制物-1（PAI-1）。结果辛伐他汀组治疗4周后，CRP、TC、TG、LDL—C、PAI-1较治疗前下降（P＜0．05或0．01）。常规组治疗前后无明显变化（P＞0．05）。治疗前AMI患者血清cRP与PAI-1活性呈正相关（r=0．393，P＜0．05），与t．PA呈负相关（r=-0．359，P＜0．01）。辛伐他汀组治疗后CRP、PAI-1、t—PA与TC、LDL-C水平变化无相关性。结论在AMI早期给予大剂量辛伐他汀治疗，可能有利于抑制炎症反应，稳定斑块，提高纤溶活性。