Tissue-type Plasminogen Activator Levels Research Articles

Screening of placenta accreta spectrum disorder using maternal serum biomarkers and clinical indicators: a case–control study

BackgroundPlacenta accreta spectrum (PAS) disorder is a major cause of postpartum hemorrhage-associated maternal and fetal death, and novel methods for PAS screening are urgently needed for clinical application.MethodsThe purpose of this study was to develop new methods for PAS screening using serum biomarkers and clinical indicators. A total of 95 PAS cases and 137 controls were enrolled in a case–control study as cohort one, and 44 PAS cases and 35 controls in a prospective nested case–control study were enrolled as cohort two. All subjects were pregnant women of Chinese Han population. Biomarkers for PAS from maternal blood samples were screened based on high-throughput immunoassay and were further validated in three phases of cohort one. Screening models for PAS were generated using maternal serum biomarkers and clinical indicators, and were validated in two cohorts. The expression levels of biomarkers were analyzed using histopathological and immunohistochemical (IHC) techniques, and gene expression was examined by QPCR in the human placenta. Binary logistic regression models were built, and the area under the curve (AUC), sensitivity, specificity, and Youden index were calculated. Statistical analyses and model building were performed in SPSS and graphs were generated in GraphPad Prism. The independent-sample t test was used to compare numerical data between two groups. For nonparametric variables, a Mann–Whitney U test or a X2 test was used.ResultsThe results demonstrated that the serum levels of matrix metalloproteinase-1 (MMP-1), epidermal growth factor (EGF), and vascular endothelial growth factor-A (VEGF-A) were consistently higher, while the level of tissue-type plasminogen activator (tPA) was significantly lower in PAS patients compared with normal term controls and patients with pre-eclampsia (PE) and placenta previa (PP). IHC and QPCR analysis confirmed that the expression of the identified biomarkers significantly changed during the third trimester in human placenta. The generated screening model combining serum biomarkers and clinical indicators detected 87% of PAS cases with AUC of 0.94.ConclusionsSerum biomarkers can be used for PAS screening with low expense and high clinical performance; therefore, it may help to develop a practicable method for clinical prenatal PAS screening.

Plasma Levels of Tissue-Type Plasminogen Activator (tPA) in Normal Aging and Alzheimer's Disease: Links With Cognition, Brain Structure, Brain Function and Amyloid Burden.

Tissue-type plasminogen activator (tPA) is a protease known for its fibrinolytic action but is also involved in physiological and pathophysiological aging processes; including amyloid elimination and synaptic plasticity. The aim of the study was to investigate the role of tPA in cognitive and brain aging. Therefore, we assessed the links between tPA plasma concentration and cognition, structural MRI, FDG-PET and Flobetapir-PET neuroimaging in 155 cognitively unimpaired adults (CUA, aged 20-85 years old) and 32 patients with Alzheimer's disease (ALZ). A positive correlation was found between tPA and age in CUA (p < 0.001), with males showing higher tPA than females (p = 0.05). No significant difference was found between ALZ patients and cognitively unimpaired elders (CUE). Plasma tPA in CUA negatively correlated with global brain volume. No correlation was found with brain FDG metabolism or amyloid deposition. Age-related tPA changes were associated to changes in blood pressure, glycemia and body mass index. Within the ALZ patients, tPA didn't correlate with any cognitive or neuroimaging measures, but only with physiological measures. Altogether our study suggests that increased tPA plasma concentration with age is related to neuronal alterations and cardiovascular risk factors.

Plasma tissue plasminogen activator and plasminogen activator inhibitor-1 in hospitalized COVID-19 patients

Patients with coronavirus disease-19 (COVID-19) are at high risk for thrombotic arterial and venous occlusions. However, bleeding complications have also been observed in some patients. Understanding the balance between coagulation and fibrinolysis will help inform optimal approaches to thrombosis prophylaxis and potential utility of fibrinolytic-targeted therapies. 118 hospitalized COVID-19 patients and 30 healthy controls were included in the study. We measured plasma antigen levels of tissue-type plasminogen activator (tPA) and plasminogen activator inhibitor-1 (PAI-1) and performed spontaneous clot-lysis assays. We found markedly elevated tPA and PAI-1 levels in patients hospitalized with COVID-19. Both factors demonstrated strong correlations with neutrophil counts and markers of neutrophil activation. High levels of tPA and PAI-1 were associated with worse respiratory status. High levels of tPA, in particular, were strongly correlated with mortality and a significant enhancement in spontaneous ex vivo clot-lysis. While both tPA and PAI-1 are elevated among COVID-19 patients, extremely high levels of tPA enhance spontaneous fibrinolysis and are significantly associated with mortality in some patients. These data indicate that fibrinolytic homeostasis in COVID-19 is complex with a subset of patients expressing a balance of factors that may favor fibrinolysis. Further study of tPA as a biomarker is warranted.

Tranexamic acid rapidly inhibits fibrinolysis, yet transiently enhances plasmin generation in vivo.

Tranexamic acid (TXA) is a lysine analogue that inhibits plasmin generation and has been used for decades as an antifibrinolytic agent to reduce bleeding. Recent reports have indicated that TXA can paradoxically promote plasmin generation. Blood was obtained from 41 cardiac surgical patients randomly assigned to TXA or placebo before start of surgery (preOP), at the end of surgery (EOS), then again on postoperative day 1 (POD-1) as well as POD-3. Plasma levels of tissue-type plasminogen activator (t-PA), urokinase (u-PA), the plasmin-antiplasmin (PAP) complex, as well as t-PA and u-PA-induced clot lysis assays were then determined. Clot lysis and PAP complex levels were also assessed in healthy volunteers before and at various time points after taking 1 g TXA orally. Surgery induced an increase in circulating t-PA, yet not u-PA at EOS. t-PA levels were unaffected by TXA; however, u-PA levels were significantly reduced in patients on POD-3. t-PA and u-PA-induced clot lysis were both inhibited in plasma from TXA-treated patients. In contrast, PAP complex formation, representing plasmin generation, was unexpectedly enhanced in the plasma of patients administered TXA at the EOS time point. In healthy volunteers, oral TXA effectively blocked fibrinolysis within 30 min and blockade was sustained for 8 h. However, TXA also increased PAP levels in volunteers 4 h after administration. Our findings demonstrate that TXA can actually augment PAP complex formation, consistent with an increase in plasmin generation in vivo despite the fact that it blocks fibrinolysis within 30 min. This may have unanticipated consequences in vivo.

Tumor Necrosis Factor-α Induces Activation of Coagulation and Fibrinolysis in Baboons Through an Exclusive Effect on the p55 Receptor

Tumor necrosis factor-alpha (TNF-alpha) can bind to two distinct transmembrane receptors, the p55 and p75 TNF receptors. We compared the capability of two mutant TNF proteins with exclusive affinity for the p55 or p75 TNF receptor with that of wild type TNF, to activate the hemostatic mechanism in baboons. Both activation of the coagulation system, monitored by the plasma levels of thrombin-antithrombin III complexes, and activation of the fibrinolytic system (plasma levels of tissue-type plasminogen activator, and plasminogen activator inhibitor type I), were of similar magnitude after intravenous injection of wild type TNF or the TNF mutant with affinity only for the p55 receptor. Likewise, wild type TNF and the TNF p55 specific mutant were equally potent in inducing neutrophil degranulation (plasma levels of elastase-alpha 1-antitrypsin complexes). Wild type TNF tended to be a more potent inducer of secretory phospholipase A2 release than the p55 specific TNF mutant. Administration of the TNF mutant binding only to the p75 receptor did not induce any of these responses. We conclude that TNF-Induced stimulation of coagulation, fibrinolysis, neutrophil degranulation, and release of secretory phospholipase A2 are predominantly mediated by the p55 TNF receptor.

Increased Circulating Levels of Tissue-Type Plasminogen Activator Are Associated with the Risk of Spontaneous Abortion During the First Trimester of Pregnancy.

Spontaneous abortion is a common complication in early pregnancy, with an incidence of around 20%. Ultrasound scan and measurement of human chorionic gonadotropin are used to identify patients at risk of spontaneous abortion; however, there is a clinical need to find new biomarkers to prospectively identify patients before the onset of clinical symptoms. Here, we aim to investigate potential biomarkers of spontaneous abortion taken in the first clinical appointment of pregnancy. A case–control study was conducted based on a prospectively collected cohort in which cases and controls were retrospectively stratified based on pregnancy outcome: normal healthy pregnancies (controls = 33) and pregnancies that ended in spontaneous abortion (cases = 10). We evaluated extracellular vesicles isolated by precipitation with ExoQuick™ and protein concentrations of tissue plasminogen activator, leptin, and adiponectin measured by ELISA. The extracellular vesicles showed the typical morphology and membrane proteins: CD63, Alix, and Flotilin-1. The size distributions of the isolated extracellular vesicles were 112 ± 27 and 118 ± 28 nm in diameter for controls and spontaneous abortion, respectively, and the total amount of extracellular vesicles did not show any difference between controls and the spontaneous abortion group. The tissue plasminogen activator showed a significant difference (p = 0.0004) between both groups, although neither adiponectin nor leptin revealed significant changes, indicating that women who had spontaneous abortions have significantly higher levels of tissue plasminogen activator than women who had normal pregnancies.

DNA Methylation of Proximal PLAT Promoter in Chronic Rhinosinusitis With Nasal Polyps.

Background Nasal polyps (NP) are characterized by pseudocysts derived from stromal tissue edema and cause persistent infections in patients with chronic rhinosinusitis (CRS). A low level of tissue-type plasminogen activator (gene name PLAT) is considered a cause of stromal tissue edema because of insufficient plasmin activation in NP; however, the mechanism regulating PLAT gene expression levels is still unclear. The epigenetic mechanism regulating the PLAT gene expression has been studied in other tissues. Objective We aimed to investigate the methylation levels in the proximal PLAT promoter and their effects on gene expression in NP tissue. Methods We investigated the methylation levels at 3 CpG sites in the proximal PLAT promoter regions (-618, -121, and -105 with respect to the transcription initiation site) by bisulfite pyrosequencing and their effects on the gene expression by quantitative real-time polymerase chain reaction (qPCR) in 20 paired samples of NP and inferior turbinate tissue (IT) from patients with CRS. Results The DNA methylation levels at all CpG sites were higher ( P < .01), and the PLAT expression was lower ( P < .001) in NP compared with IT. The methylation changes at the -618 site showed a negative correlation with the gene expression changes between NP and IT ( r = -.65, P < .01). Conclusions Hypermethylation of PLAT promoter may downregulate the gene expression in NP, leading to excessive fibrin deposition by aberrant coagulation cascade. DNA methylation of proximal PLAT promoter may contribute to NP growth and have a potential as a new therapeutic target.

Hemostasis during Extreme Exertion.

Exercise is protective against cardiovascular disease, but can also provoke sudden cardiac death, a phenomenon referred to as "the exercise paradox." Extreme exertion is known to induce a rebalanced hemostatic state by causing hypercoagulability and concomitantly enhanced fibrinolysis. Over the past decade, novel techniques for quantifying hemostasis have been introduced, which may provide new insights into this process. This review summarizes recent literature on the effect of extreme exertion of both short and long duration on coagulation, fibrinolysis, and recovery of hemostatic balance. Extreme exertion introduces a temporary hypercoagulable state, mainly through upregulation of the contact pathway by increased FVIII levels. Additionally, von Willebrand factor levels and platelet activation are increased. Simultaneously, increased fibrinolysis results from increased tissue-type plasminogen activator levels, suggesting a rebalanced hemostasis. The vascular endothelium appears to play a pivotal role in both processes. Data on the effect of exercise on endogenous anticoagulants are scarce. Hypercoagulability persists for hours to a day after prolonged extreme exertion, while fibrinolytic parameters appear to return to baseline levels more quickly. Hence, the balance in the rebalanced hemostatic state may be lost during recovery. Training induces lower amplitude of the hypercoagulable response, and quicker recuperation toward baseline. Repetitive exercise exhausts the endothelium, attenuating procoagulant changes. Additional research is needed to identify if the hemostatic balance is lost during recovery, and if so, when the shift toward thrombosis appears. Moreover, differences between sexes need to be addressed, since women are known to have a different pathophysiological mechanism behind cardiovascular events, but are underrepresented in recent literature.

Vitronectin Regulates the Fibrinolytic System during the Repair of Cerebral Cortex in Stab-Wounded Mice.

Vitronectin (VN), one of the serum proteins, is known to be involved in the regulation of blood coagulation, fibrinolysis, and cell migration. It has been proposed that the regulation of fibrinolysis by VN promotes the blood-brain barrier (BBB) recovery from brain injuries such as traumatic injury and subarachnoid hemorrhage. The effects of VN on fibrinolysis in the injured brain remain unclear, however. We examined the effects of VN on the fibrinolytic system in the stab-wounded cerebral cortex of VN-knockout (KO) mice. First, hemorrhage and recovery from BBB breakdown in the wounded regions were assessed by serum immunoglobulin G (IgG) extravasation. The level of IgG extravasation increased 3-7 days after the stab wound (D3-7) in the cortex of VN-KO mice, compared with that in wild type mice, indicating that VN deficiency inhibited the recovery from BBB breakdown. The VN deficiency decreased fibrin fiber deposition at D1-3, suggesting that VN deficiency tilts the balance between fibrinogenesis and fibrinolysis toward fibrinolysis. Next, the effects of VN deficiency on the fibrinolytic factors were analyzed in the stab-wounded cortex. The VN deficiency impaired the activity of plasminogen activator inhibitor-1, an inhibitor of the fibrinolytic system, at D3-5. Further, VN deficiency up-regulated the mRNA and protein expression levels of tissue-type plasminogen activator, and urokinase-type plasminogen activator. These results demonstrate that VN contributes to the regulation of the fibrinolytic system and recovery from BBB breakdown in the wounded brain.

Detection of early endothelial damage in patients with Raynaud's phenomenon

ObjectivesRaynaud's phenomenon (RP) can be the first manifestation of systemic sclerosis (SSc) or other connective tissue diseases (CTDs), often preceding an overt disease by years. It is not known if markers of endothelial damage are detectable in those RP patients who subsequently develop a CTD. MethodsWe studied 82 RP patients at their first evaluation to correlate the levels of endothelial markers with the subsequent development of an overt disease 36months later. We measured plasma levels of tissue-type plasminogen activator (t-PA) and von Willebrand factor (vWF), two markers of endothelial damage, and interleukin-6 (IL-6), a pro-inflammatory cytokine. Thirty sex- and age-matched healthy subjects (HS) served as controls. ResultsAt baseline, 67 patients showed capillaroscopic normal pattern (CNP) and 15 patients, of which 11 were very early SSc, had capillaroscopic scleroderma pattern (CSP). Plasma levels of t-PA, vWF and IL-6 were higher in patients with CNP (p=0.0001) than in HS and even much higher in patients with CSP (p=0.0001). In patients with CNP and RP of recent onset (<18months), vWF plasma levels were higher when autoantibodies were present (p=0.020). After 36months, among 48 RP patients with CNP who remained in follow-up, 24 were diagnosed as primary and 24 as secondary RP. In secondary RP, basal levels of t-PA, IL-6 and particularly vWF were higher than in primary RP (p=0.005, p=0.004, p=0.0001 respectively) and HS (p=0.0001 for all). ConclusionsOur findings indicate that markers of endothelial damage are elevated in RP patients who subsequently develop SSc or other CTDs, even in the absence of capillaroscopic abnormalities.

Adolescents with Classical Polycystic Ovary Syndrome Have Alterations in the Surrogate Markers of Cardiovascular Disease but Not in the Endothelial Function. The Possible Benefits of Metformin

Study ObjectiveTo study whether adolescents with the classical form of polycystic ovary syndrome (PCOS) have alterations in metabolic and vascular structure and function. The effect of metformin was evaluated. DesignControlled study. SettingUniversity outpatient clinic. ParticipantsEighteen nonobese adolescents with PCOS were enrolled. Seventeen healthy age-matched adolescents were recruited as control subjects. InterventionsThe metabolic profile and the endothelial structure and function were evaluated. Main Outcome MeasuresHormonal and lipid profile, blood pressure (BP) measurement, fasting glucose and insulin levels, C-reactive protein (CRP), homocysteine, tissue-type plasminogen activator, plasminogen activator inhibitor-1 (PAI-1), and plasmin-antiplasmin complexes (PAP) were measured. Flow mediated dilation (FMD), central pulse wave velocity (PWV), radial artery pulse wave, and common carotid intima-media thickness (IMT) were also assessed. Girls with PCOS were also studied 6 months after treatment with metformin (850 mg twice per day). ResultsAdolescents with PCOS were insulin resistant and/or hyperinsulinemic and they had higher BP values and levels of CRP and PAI-1 than the control subjects. The levels of tissue-type plasminogen activator and PAP were similar in both groups. FMD, PWV, and IMT were also similar. Metformin significantly (P < .05) reduced insulin, BP, CRP, and PAI-1 levels. The PAP levels significantly (P < .05) increased. Radial artery pulse wave was significantly reduced after metformin treatment. No modifications in FMD, PWV, and IMT were observed. ConclusionAdolescents with classical PCOS have alterations in some surrogate markers of cardiovascular risk and they are ameliorated by metformin. No deterioration of vascular structure and function has been detected, probably because of the short duration of exposure to the disease.

Haemostatic biomarkers are associated with long-term recurrent vascular events after ischaemic stroke.

Ischaemic stroke patients continue to be at risk for recurrent vascular events for many years. Predictors of long-term prognosis are needed. It was the objective of this study to investigate levels of four haemostatic proteins as long-term predictors of recurrent vascular events after ischaemic stroke. We prospectively followed 548 ischaemic stroke patients, 18-69 years, and registered recurrent vascular events. Plasma levels of tissue-type plasminogen activator (t-PA), von Willebrand factor (VWF), fibrinogen and thrombin activatable fibrinolysis inhibitor activation peptide (TAFI-AP) were measured three months after index stroke. Cox regression models were used to assess associations to outcomes for single biomarkers and for a combined biomarker measure. For single biomarkers significantly associated with any of the outcomes, we performed subanalyses stratified for age, sex, diabetes and atherosclerosis. During 5,637 person-years of follow-up, we registered 74 vascular deaths, 90 recurrent strokes and 62 coronary events. Levels of t-PA, VWF and fibrinogen were significantly associated with vascular death and coronary events. After adjustment, the association between t-PA and vascular death remained (HR per 1 SD increase in plasma level 1.27, 95 % CI 1.00-1.61, p=0.047). The combined effect of t-PA, VWF and fibrinogen was associated with coronary events (adjusted HR 1.35, 1.02-1.80, p=0.04). In non-diabetic patients, an association with coronary events was seen for VWF levels (adjusted HR 2.23, 1.45-3.43, p<0.01). In conclusion, plasma levels of haemostatic factors were associated with vascular death and coronary events, but not with recurrent stroke. Our results suggest that the predictive value of biomarkers differ by specific outcome measure and subgroup of patients.

Fibrinolysis status in the Budd-Chiari syndrome in China.

Pathogenesis and clinical characteristics of the Budd-Chiari syndrome (BCS) in Asia are somewhat different from the ones observed in Western countries. Obstruction of the inferior vena cava (IVC) or of the hepatic veins is caused to a greater extent by membranous webs than by thrombosis. Impaired fibrinolysis has been found in European patients with BCS, but its status in Chinese patients with this condition is still unknown. To explore the characteristics of fibrinolysis in BCS patients in this country, we measured the euglobulin lysis time (ELT) for overall fibrinolysis and the plasma levels of five fibrinolytic components in 65 Chinese patients with BCS and 43 healthy controls. In patients, ELTs were slightly shorter than in controls (mean, 293 vs. 357 min, P < 0.02), tissue type plasminogen activator levels were higher than in controls (mean, 239 vs. 185 pg/ml, P < 0.01), and plasminogen activator inhibitor 1 levels were lower than in controls (mean, 1.43 vs. 1.73 ng/ml, P < 0.001). To explore BCS in more detail, we subgrouped the cases according to age, type of venous occlusion, Child-Pugh score, and thrombosis. As a result of this analysis, we found that young patients (age <30 years) had a longer ELT (mean, 440 min) than the older patient groups (30 ≤ age ≤ 44, 45 ≤ age ≤ 54, age>54 years; mean ELT = 242, 198, and 289 min, respectively, all P < 0.05). The independent hepatic vein occlusion subgroup showed a longer ELT (mean, 367 min) than the combined hepatic vein and IVC or the independent IVC occlusion subgroup (mean ELT = 233 and 260 min, both P < 0.05). ELT did not show significant differences between Child-Pugh class A and B subgroups (mean, 267 vs. 333 min, P > 0.05). ELT in the subgroup without thrombosis was shorter than in controls (mean, 288 vs. 358 min, P < 0.05), and in the subgroup with thrombosis, it was also slightly shorter than in controls, without reaching statistical significance (mean, 306 vs. 358 min, P > 0.05). By and large, overall fibrinolytic potential was slightly increased in Chinese patients with BCS in this study, but fibrinolysis differed according to its baseline characteristics. Compared with the one seen in BCS patients from Western countries, BCS in China exhibits certain special changes in fibrinolysis and we were able to explain some of these changes.

The Fibrinolytic Status in Liver Diseases.

The liver is the main site of synthesis and/or clearance of proteins involved in fibrinolysis. Therefore, chronic liver disease, including cirrhosis, leads to altered plasma levels of fibrinolytic proteins. Historical studies using in vitro clot lysis assays suggested that patients with chronic liver disease had accelerated fibrinolysis. Subsequent studies measured levels of individual pro- and antifibrinolytic proteins and showed that levels of tissue-type plasminogen activator are elevated. Plasma levels of plasminogen activator inhibitor-1 may also be altered, which leads to a shift in balance in the fibrinolytic system. Despite the fact that a more recent study using a plasma clot lysis assay challenged the existence of hyperfibrinolysis, other recent studies detected hyperfibrinolysis in a considerable number of patients with cirrhosis. Therefore, it is now recognized that hyperfibrinolysis may occur in 30 to 50% of patients with end-stage liver disease. A causal role of hyperfibrinolysis in bleeding is difficult to establish because also other concomitant changes in hemostasis occur. Treatment of hyperfibrinolysis consists of the use of fibrinolysis inhibitors, such as tranexamic acid. In this review we summarize current insights of the role of the liver in fibrinolysis, changes in fibrinolytic proteins, the potential clinical implications, and management of hyperfibrinolysis in liver disease.

Short-term venous stasis induces fibrinolytic activation but not thrombin formation.

Venous stasis is a well-known risk factor for the development of venous thromboembolism. It is likely that stasis increases the risk of thrombosis by inducing hypercoagulability via the hypoxic procoagulant activation of endothelial and mononuclear cells and the accumulation of activated clotting factors. However, increased rates of thrombin formation have not been demonstrated in response to venous stasis in vivo. In this study, we used the venous occlusion (VO) test to determine, if stasis triggers thrombin formation in healthy individuals (n=25) and patients with additional thrombotic risk factors, such as inherited thrombophilia (n=19) and symptomatic atherosclerosis (n=15). Thrombin formation was monitored by measuring plasma levels of free thrombin using a highly sensitive oligonucleotide enzyme capture assay (OECA) in addition to the plasma levels of prothrombin fragment 1+2 (F1+2) and thrombin-antithrombin-complexes (TAT). The plasma levels of activated protein C (APC) were additionally measured using an APC-OECA. VO induced a significant (p<0.05) increase in the levels of tissue-type plasminogen activator and plasmin-α2-antiplasmin-complexes. In all three cohorts, the majority of samples obtained during VO showed no quantifiable thrombin or APC levels. Consistent with these findings F1+2 and TAT did not change. We conclude that short-term venous stasis induces a profibrinolytic response due to the activation of endothelial cells, but not a prothrombotic response, even in the presence of additional thrombophilic risk factors. Furthermore, our results support the hypothesis that the stasis-induced profibrinolytic activation of endothelial cells occurs independently from thrombin formation.

Tissue-type plasminogen activator is an extracellular mediator of Purkinje cell damage and altered gait

Purkinje neurons are a sensitive and specialised cell type important for fine motor movement and coordination. Purkinje cell damage manifests as motor incoordination and ataxia — a prominent feature of many human disorders including spinocerebellar ataxia and Huntington's disease. A correlation between Purkinje degeneration and excess cerebellar levels of tissue-type plasminogen activator (tPA) has been observed in multiple genetically-distinct models of ataxia. Here we show that Purkinje loss in a mouse model of Huntington's disease also correlates with a 200% increase in cerebellar tPA activity. That elevated tPA levels arise in a variety of ataxia models suggests that tPA is a common mediator of Purkinje damage. To address the specific contribution of tPA to cerebellar dysfunction we studied the T4 mice line that overexpresses murine tPA in postnatal neurons through the Thy1.2 gene promoter, which directs preferential expression to Purkinje cells within the cerebellum. Here we show that T4 mice develop signs of cerebellar damage within 10weeks of birth including atrophy of Purkinje cell soma and dendrites, astrogliosis, reduced molecular layer volume and altered gait. In contrast, T4 mice displayed no evidence of microgliosis, nor any changes in interneuron density, nor alteration in the cerebellar granular neuron layer. Thus, excess tPA levels may be sufficient to cause targeted Purkinje cell degeneration and ataxia. We propose that elevated cerebellar tPA levels exert a common pathway of Purkinje cell damage. Therapeutically lowering cerebellar tPA levels may represent a novel means of preserving Purkinje cell integrity and motor coordination across a wide range of neurodegenerative diseases.

Behçet’s disease: new insight into the relationship between procoagulant state, endothelial activation/damage and disease activity

BackgroundBehçet disease (BD) is associated with a prothrombotic state of unknown origin that may lead to life-threatening events. Calibrated Automated Thrombogram (CAT) and Rotational Thromboelastometry (ROTEM) are two global haemostasis assays that may reveal new insights into the physiopathological mechanisms of the disease and its procoagulant condition.Methods23 BD patients who had no signs or symptoms of current thrombosis and 33 age- and sex-matched controls were included in the study. We performed ROTEM and CAT tests and assessed erythrocyte count, platelet count, platelet contribution to clot formation and plasma levels of tissue-type plasminogen activator, plasminogen activator inhibitor type 1 (PAI-1), fibrinogen, C-reactive protein (CRP), thrombin-antithrombin III complex (TAT), D-dimer and E-selectin (ES).ResultsBoth ROTEM and CAT tests showed a hypercoagulable state in the BD patients. Plasma levels of PAI-1, fibrinogen, TAT, CRP and ES were significantly increased in this group compared to controls. The disease activity (DA) was significantly correlated with levels of ES and the maximum clot firmness, and this last one, in turn, correlated with rising levels of ES, PAI-1, CRP and fibrinogen. CAT parameters did not correlate with DA or ES.ConclusionsBoth ROTEM and CAT tests reveal that patients with BD have a procoagulant state even in the absence of thrombosis. ROTEM test indicates that increased levels of fibrinogen and PAI-1 may be involved in the prothrombotic state of this pathology, while platelets do not significantly contribute. Moreover, CAT assay demonstrate that plasma from BD patients is able to generate more thrombin than controls in response to the same stimulus and that this effect is independent of the DA and the endothelial impairment suggesting the involvement of another factor in the hypercoagulable state observed in BD patients. This study also shows that endothelium activation/damage may be a contributing factor in both the procoagulant and clinical conditions of BD, as shown by the direct correlation between ES levels, ROTEM parameters and DA.

Receptors to interleukin-6 and adhesion molecules on circulating monocyte subsets in acute myocardial infarction

The role of individual monocyte subsets in inflammation and recovery post-myocardial infarction (MI) is insufficiently understood. It was the objective of this study to evaluate the dynamics of monocyte expression of receptors to vascular cell adhesion molecule (VCAM-1r), intercellular adhesion molecule (ICAM-1r), and interleukin-6 (IL-6r) following MI and their relation to inflammatory cytokines, fibrinolytic factors and annexin V-binding microparticles. Expression of VCAM-1r, ICAM-1r, IL-6r on CD14++CD16-(Mon1), CD14++CD16+(Mon2), CD14+CD16++(Mon3) monocyte subsets were quantified by flow cytometry in patients with ST-elevation MI (STEMI, n=50), non-STEMI (n=48) and stable coronary artery disease (n=40). In STEMI, parameters were measured on days 1, 3, 7, 30. On admission with STEMI, VCAM-1r expression was reduced on Mon1 (p=0.007), Mon2 (p=0.036), Mon3 (p=0.005), whilst in NSTEMI there was significant up-regulation of expression by Mon2 (p=0.024) and Mon3 (p=0.049). VCAM-1r on Mon1 correlated positively with plasma IL-1β levels (p=0.001). IL-6r was reduced on Mon2 in acute STEMI, with upregulation of the receptor on Mon1 and Mon2 during follow-up. IL-6r density correlated negatively with plasma levels of tissue-type plasminogen activator (p=0.0005 for Mon1, p=0.001 for Mon2 and Mon3), and positively with annexin V-binding microparticles (p=0.03 for Mon1, p=0.005 for Mon2 and p=0.005 for Mon3). There was no change in monocyte ICAM-1r expression. In conclusion, expression of IL-6r and VCAM-1r is reduced on circulating monocyte subsets involved in inflammatory responses in STEMI. This may represent a regulatory feed-back mechanism aiming to re-balance the marked inflammation which is typically present following acute MI or selective homing of monocytes with high receptor expression to damaged myocardium.

CXCR4 positive and angiogenic monocytes in myocardial infarction

Limited data are available on the role of monocytes in cardiac repair. In the present study, we evaluated the dynamic alterations of monocytes with reparative and angiogenic potential in patients with myocardial infarction(MI). Reparative CXCR4+ monocytes, and CD34+ and KDR+ monocytes with angiogenic potential derived from individual monocyte subsets were quantified by flow cytometry in patients with ST-elevation MI (n=50) and stable coronary artery disease (CAD, n=40). Parameters were measured on days 1, 3, 7 and 30 post MI. Monocyte subsets were defined as CD14++CD16-CCR2+ ('classical', Mon1), CD14++CD16+CCR2+ ('intermediate', Mon2), CD14+CD16++CCR2- ('non-classical', Mon3). Plasma levels of inflammatory cytokines, fibrinolytic factors and microparticles (MPs) were assessed on day 1. CXCR4+ and KDR+ monocytes were increased following MI, being more prominently associated with Mon2 (median[IQR] of CXCR4+ Mon2 60[25-126] per μl in STEMI vs. 27[21-41] per μl in stable CAD). The counts of CXCR4+ Mon2 in STEMI significantly reduced by day 30 of follow-up (27[18-47], p<0.001). Expression of the pro-reparative scavenger receptor CD163 on Mon3 was reduced in acute MI (p=0.008), and on other subsets later during the follow-up with lowest levels at day 3 post-MI (p<0.001 for Mon1, p=0.02 for Mon2). CD204 expression on Mon1 correlated with tissue type plasminogen activator levels (r=0.46, p=0.001). Interleukin(IL)6 levels correlated with counts of Mon2-derived CXCR4+ and KDR+ cells. Interleukin-1β correlated with KDR+ Mon2 counts. IL10 correlated with CXCR4+ Mon2 levels. Low count of CXCR4+ Mon2 and low CD163 expression by Mon2 were associated with higher ejection fraction six-weeks after MI. In conclusion, the Mon2 subset has the most prominent role in the observed changes in reparative monocytes in MI. The association of reparative monocytes with inflammatory/fibrinolytic markers indicates a complex interplay of these cells in the post-MI state.

Endogenous tissue-type plasminogen activator impairs host defense during severe experimental gram-negative sepsis (melioidosis)*

Melioidosis is a frequent cause of severe sepsis in Southeast Asia caused by the gram-negative bacterium Burkholderia pseudomallei. Patients with melioidosis have elevated circulating levels of tissue-type plasminogen activator, an important regulator of fibrinolysis. In this study, we aimed to investigate the role of tissue-type plasminogen activator during melioidosis. Animal study. University research laboratory. Wild-type and tissue-type plasminogen activator-deficient C57BL/6 mice. Mice were intranasally infected with viable Burkholderia pseudomallei and killed after 24, 48, or 72 hrs for harvesting of lungs, liver, and blood. Additionally, survival studies were performed. Experimentally induced melioidosis was associated with elevated levels of tissue-type plasminogen activator in lungs of infected wild-type mice. During infection with Burkholderia pseudomallei, tissue-type plasminogen activator-deficient mice were protected when compared to wild-type mice as demonstrated by a strongly decreased mortality (62% vs. 100% amongst wild-type mice, p < .0001), together with decreased pulmonary bacterial loads, less severe histopathological scores, and decreased fibrinolysis. These results were accompanied with an early increase in cytokine levels in tissue-type plasminogen activator-deficient mice. During severe gram-negative sepsis caused by Burkholderia pseudomallei, endogenous tissue-type plasminogen activator has harmful effects with respect to survival and pulmonary bacterial growth. These effects are related to tissue-type plasminogen activator-associated plasmin-induced fibrinolysis and/or a tissue-type plasminogen activator-associated decrease in proinflammatory cytokine production.