Plasminogen activator inhibitor-1 influences cerebrovascular complications and death in pneumococcal meningitis.

Cerebrovascular complications are common in pneumococcal meningitis and are a main determinant of unfavourable outcome and death. We hypothesized that plasminogen activator inhibitor-1 (PAI-1) is a major contributor to cerebrovascular complications and death in pneumococcal meningitis. In a nationwide prospective cohort study we evaluated the effect of the 4G/5G polymorphism (rs1799889) in SERPINE1 (coding for PAI-1) on cerebrovascular complications and outcome in adults with pneumococcal meningitis proven by cerebrospinal fluid (CSF) culture. From 2006 to 2011, a total of 991 adult patients with community-acquired bacterial meningitis were included in the cohort and 712 had pneumococcal meningitis. The rs1799889 5G/5G genotype was associated with an increased risk of unfavourable outcome [odds ratio (OR) 1.69, 95 % confidence interval (CI) 1.03-2.78] and mortality (OR 2.20, 95 % CI 1.02-4.86) in white adults with pneumococcal meningitis. rs1799889 was associated with CSF PAI-1 concentrations (P = 0.048), and white patients homozygous for the low PAI-1 producing genotype (5G/5G) had a significantly higher risk for cerebral infarctions (P = 0.015) and haemorrhages (P = 0.005). Subsequently, we assessed the functionality of PAI-1 in a pneumococcal meningitis mouse model, using Serpine1 knockout mice. Consistent with the human data, Serpine1-deficient mice had increased mortality and cerebral haemorrhages compared to wild-type mice. We conclude PAI-1 is protective for death in humans and mice with pneumococcal meningitis by reducing cerebrovascular complications.

Plasmin system of Alzheimer's disease patients: CSF analysis.

Alzheimer's disease (AD) is a multifactorial neurodegenerative disorder characterized by the extracellular deposit of Amyloid beta (Aß), mainly of the Amyloid beta(1-42) (Aß(1-42)) peptide in the hippocampus and neocortex leading to progressive cognitive decline and dementia. The possible imbalance between the Aß production/degradation process was suggested to contribute to the pathogenesis of AD. Among others, the serine protease plasmin has shown to be involved in Aß(1-42) clearance, a hypothesis strengthened by neuropathological studies on AD brains. To explore whether there is a change in plasmin system in CSF of AD patients, we analyzed CSF samples from AD and age-matched controls, looking at plasminogen, tissue plasminogen activator (t-PA) and plasminogen activator inhibitor (PAI-1) protein levels and t-PA and urokinase plasminogen activator (u-PA) enzymatic activities. We also measured Aß(1-42), total-tau and phospho-tau (181) CSF levels and sought for a possible relationship between them and plasmin system values. Our findings showed that t-PA, plasminogen and PAI-1 levels, as t-PA enzymatic activity, remained unchanged in AD with respect to controls; u-PA activity was not detected. We conclude that CSF analysis of plasminogen system does not reflect changes observed post-mortem. Unfortunately, the CSF detection of plasmin system could not be a useful biomarker for either AD diagnosis or disease progression. However, these findings do not exclude the possible involvement of the plasmin system in AD.

Altered secretory and neuroprotective function of the choroid plexus in progressive multiple sclerosis.

The choroid plexus (CP) is a key regulator of the central nervous system (CNS) homeostasis through its secretory, immunological and barrier properties. Accumulating evidence suggests that the CP plays a pivotal role in the pathogenesis of multiple sclerosis (MS), but the underlying mechanisms remain largely elusive. To get a comprehensive view on the role of the CP in MS, we studied transcriptomic alterations of the human CP in progressive MS and non-neurological disease controls using RNA sequencing. We identified 17 genes with significantly higher expression in progressive MS patients relative to that in controls. Among them is the newly described long non-coding RNA HIF1A-AS3. Next to that, we uncovered disease-affected pathways related to hypoxia, secretion and neuroprotection, while only subtle immunological and no barrier alterations were observed. In an ex vivo CP explant model, a subset of the upregulated genes responded in a similar way to hypoxic conditions. Our results suggest a deregulation of the Hypoxia-Inducible Factor (HIF)-1 pathway in progressive MS CP. Importantly, cerebrospinal fluid levels of the hypoxia-responsive secreted peptide PAI-1 were higher in MS patients with high disability relative to those with low disability. These findings provide for the first time a complete overview of the CP transcriptome in health and disease, and suggest that the CP environment becomes hypoxic in progressive MS patients, highlighting the altered secretory and neuroprotective properties of the CP under neuropathological conditions. Together, these findings provide novel insights to target the CP and promote the secretion of neuroprotective factors into the CNS of progressive MS patients.

IGF1R as a Key Target in High Risk, Metastatic Medulloblastoma.

Risk or presence of metastasis in medulloblastoma causes substantial treatment-related morbidity and overall mortality. Through the comparison of cytokines and growth factors in the cerebrospinal fluid (CSF) of metastatic medulloblastoma patients with factors also in conditioned media of metastatic MYC amplified medulloblastoma or leptomeningeal cells, we were led to explore the bioactivity of IGF1 in medulloblastoma by elevated CSF levels of IGF1, IGF-sequestering IGFBP3, IGFBP3-cleaving proteases (MMP and tPA), and protease modulators (TIMP1 and PAI-1). IGF1 led not only to receptor phosphorylation but also accelerated migration/adhesion in MYC amplified medulloblastoma cells in the context of appropriate matrix or meningothelial cells. Clinical correlation suggests a peri-/sub-meningothelial source of IGF-liberating proteases that could facilitate leptomeningeal metastasis. In parallel, studies of key factors responsible for cell autonomous growth in MYC amplified medulloblastoma prioritized IGF1R inhibitors. Together, our studies identify IGF1R as a high value target for clinical trials in high risk medulloblastoma.

Evaluation of cerebrospinal fluid uPA, PAI-1, and soluble uPAR levels in HIV-infected patients.

To evaluate the potential role of the uPAR/uPA/PAI-1 system in HIV-induced blood-brain-barrier (BBB) disruption, CSF uPA-dependent plasminogen activation (PdPA) was analyzed by casein zymography, and CSF protein levels of all three molecules were measured by ELISA. CSF uPAR, but not uPA, PAI-1, or PdPA levels was significantly increased in neurologically compromised HIV+ patients. Only individual patients with severe AIDS dementia complex had increased levels of uPA (but not PAI-1) which fell upon initiation of antiretroviral therapy. The levels of all three molecules did not correlate with the CSF to serum albumin ratio suggesting not an important role in HIV-induced BBB disruption.

Role of the urokinase plasminogen activator system in patients with bacterial meningitis.

BACKGROUND: The urokinase plasminogen activator system has the potency to promote leukocyte recruitment and blood-CSF barrier breakdown, and thus may play an important pathophysiologic role in bacterial meningitis. METHODS: CSF and serum concentrations of urokinase-plasminogen activator (urokinase [uPA]), uPA receptor (uPAR), and PA inhibitor-1 (PAI-1) were quantified by ELISA in 12 patients with bacterial meningitis, control patients (n = 10) with noninflammatory neurologic diseases, and 10 patients with Guillain-Barré syndrome (GBS), a disease in which blood-CSF barrier disruption occurs without CSF pleocytosis. Casein zymography was used to determine PA-dependent plasminogen activation in the CSF. RESULTS: A marked increase in uPA-dependent plasminogen activation was detected in the CSF of patients with bacterial meningitis vs CSF of patients with GBS and controls. Accordingly, ELISA analysis of CSF revealed intrathecal upregulation of uPA protein in patients with bacterial meningitis. CSF concentrations of uPAR and PAI-1 were also elevated in these patients. The serum of patients with bacterial meningitis showed elevated protein levels of uPA, but not uPAR or PAI-1. Positive correlations were found between blood-CSF barrier breakdown and CSF uPA concentrations, and between CSF pleocytosis and CSF/serum ratios of the potent chemokine uPAR in patients with bacterial meningitis. Furthermore, an adverse clinical outcome in these patients correlated with serum uPA concentrations. CONCLUSION: In bacterial meningitis, the urokinase plasminogen activator system is involved in leukocyte recruitment and breaching of the blood-CSF barrier, and this may contribute to an unfavorable clinical outcome.

Elevation of plasminogen activators in cerebrospinal fluid of mice with eosinophilic meningitis caused by Angiostrongylus cantonensis.

A hallmark of parasitic meningitis is the infiltration of eosinophils into the subarachnoid space. Infection with Angiostrongylus cantonensis in mice induced proteinase activity in parallel with the pathological changes of eosinophilic meningitis. Zymogram analysis demonstrated that 70 and 55 kDa proteinases from cerebrospinal fluid (CSF) were active against the casein/plasminogen substrate. The proteinase activities were clearly inhibited by phenylmethanesulphonyl fluoride but not by ethylenediamine tetraacetic acid, 1,10-phenanthroline or leupeptin. Western blotting confirmed these enzymes to be tissue-type plasminogen activator and urokinase-type plasminogen activator, respectively. High activities of tissue-type plasminogen activator and urokinase-type plasminogen activator were detected in the CSF of mice with eosinophilic meningitis, and correlated positively with CSF eosinophil numbers and total protein, respectively. Immunohistochemistry demonstrated that tissue-type plasminogen activator and urokinase-type plasminogen activator localised in the endothelial cells of blood vessels, in blood clots and in infiltrated leukocytes. These results suggest that tissue-type plasminogen activator and urokinase-type plasminogen activator may be play a role in the pathogenesis of eosinophilic meningitis of angiostrongyliasis.

Cerebrospinal fluid plasminogen activator inhibitor-1 in patients with neurological disease.

AIM: To study cerebrospinal fluid (CSF) concentrations of plasminogen activator inhibitor type-1 (PAI-1) in patients with neurological disease. METHODS: CSF PAI-1 concentrations were measured in 51 patients with neurological disease and 20 reference subjects using an ELISA. The patient group comprised three patients with viral meningitis, 20 with encephalitis, nine with acute lymphoblastic (n = 7) and myeloid (n = 2) leukaemia (with central nervous system involvement), and 19 with multiple sclerosis. RESULTS: Raised PAI-1 concentrations were observed in patients with leukaemia, encephalitis and multiple sclerosis. There was no difference in the mean concentrations of PAI-1 in patients with meningitis when compared with the reference subjects. The highest mean (SEM) PAI-1 concentration was found in patients with leukaemia (1.28 (0.36) ng/ml), and the next highest in those with encephalitis (1.19 (0.20) ng/ml). these values were much higher than those in patients with viral meningitis. In a previous report, raised CSF tissue-type plasminogen activator (tPA) activities were detected in patients with multiple sclerosis, leukaemia and encephalitis, with mean activities in decreasing order. PAI-1 concentrations in the same patients were the reverse of their corresponding tPA activities, being higher in those with leukaemia and encephalitis, than in patients with multiple sclerosis. There was no association between CSF PAI-1 concentrations and age in either patients or controls. Similarly, there was no association between CSF PAI-1 concentrations and urokinase-type plasminogen activator (uPA). CONCLUSIONS: Raised CSF PAI-1 concentrations may be used as a non-specific marker of neurological disease. Moreover, PAI-1 may play an important role in regulating the functions tPA, and probably uPA, in CSF.

Coagulative and fibrinolytic activation in cerebrospinal fluid and plasma after subarachnoid hemorrhage.

OBJECTIVE: Intrathecal fibrinolytic therapy has been used as one of the anticerebral vasospasm (VS) preventative therapies in patients with subarachnoid hemorrhage (SAH). However, the changes in coagulation and fibrinolysis in the blood and cerebrospinal fluid (CSF) after SAH remain unknown. METHODS: Fifty patients with SAH caused by ruptured cerebral aneurysms were studied postoperatively to detect the serial changes of the thrombin-antithrombin III complex, active plasminogen activator inhibitor (PAI)-1, and tissue plasminogen activator (tPA)-PAI complex (tPA-PAI) activities in the plasma and CSF collected from cisternal drainage catheters. RESULTS: The CSF levels of all parameters and plasma PAI-1 levels were significantly higher in patients with severe SAH than in those with mild SAH. There was no relationship between the CSF and plasma levels of these parameters (except the CSF levels of tPA-PAI) and the initial neurological statuses. The CSF PAI-1 levels increased to greater than 20 ng/ml near the time of the occurrence of cerebral VS, whereas they remained below 20 ng/ml in patients without VS. The CSF tPA-PAI levels showed the highest peak near the time of VS remission. The CSF PAI-1 and tPA-PAI levels were significantly lower in patients with good outcomes than in those with poor outcomes. CONCLUSION: Both the coagulative and fibrinolytic systems were activated in the CSF and plasma after SAH in correlating to the amount of SAH clot. The intrathecal administration of fibrinolytic agents should be started early after surgery, before CSF PAI-1 levels increase, for patients with severe SAH. Patients with CSF PAI-1 levels greater than 20 ng/ml experienced high incidence of VS and poor outcomes.

Plasminogen activator inhibitor-1 in the cerebrospinal fluid as an index of neurological disease.

Plasminogen activator inhibitor-1 (PAI-1) is a serpin proteinase inhibitor which regulates fibrinolysis and the proteinase cascade of tumour invasion. In this study, PAI-1 was identified in the cerebrospinal fluid (CSF) from patients without neurological disease and patients with various neurological disorders. The mean level of PAI-1 in the CSF of 28 patients without central nervous system (CNS) disease was 0.28 +/- 0.03 (SEM) ng/ml. CSF PAI-1 was significantly increased in the following diagnostic categories:dementia (Alzheimer's disease), cerebral infarction, CNS infection, alcohol withdrawal seizures and CNS neoplasia. In all these disorders, with the exception of CNS infection, PAI-1 was also increased as a fraction of total CSF protein. CSF PAI-1 was not increased in patients with hydrocephalus or idiopathic seizure disorders. Complementary plasma samples were available for 18 of the 128 CSF specimens studied. For these cases, there was no correlation between plasma PAI-1 and CSF PAI-1 levels. PAI-1 may represent a non-specific marker of disease in the central nervous system.

Coagulation and fibrinolytic activity in patients with acute cerebral infarction.

OBJECTIVE: To measure the concentration of D-dimer (DD), tissue plasminogen activator (t-PA), plasminogen activator inhibitor-1 (PAI-1) and plasminogen (PLG) activity in plasma and cerebrospinal fluid in patients with acute cerebral infarction and to investigate their clinical significance. METHODS: The concentrations of D-dimer, t-PA, and PAI-1 in plasma and cerebrospinal fluid in patients were measured by enzyme-linked immunosorbent assay (ELISA). The PLG biological activity was detected using the chromophore method. The results were compared with those of the controls. RESULTS: The concentrations of D-dimer, t-PA and PAI-1 in cerebrospinal fluid and plasma in patients with acute cerebral infarction were much higher than those of normal subjects (P < 0.01). Conversely, the level of PLG activity was significantly lower in the patients than in the controls (P < 0.01). CONCLUSION: Hypercoagulability and secondary hyperfibrinolysis exist in patients with acute cerebral infarction.

Relationship between elevated cerebrospinal fluid levels of plasminogen activator inhibitor 1 and neuronal destruction in patients with neuropsychiatric systemic lupus erythematosus.

OBJECTIVE: A homeostatic imbalance between coagulation and fibrinolysis might occur intrathecally in neuropsychiatric systemic lupus erythematosus (NPSLE). However, there are no published data on levels of fibrinolytic factors in the cerebrospinal fluid (CSF) of patients with NPSLE. The present study was undertaken to assess CSF levels of fibrinolytic molecules, including urokinase plasminogen activator (uPA), tissue plasminogen activator (tPA), D-dimer, and plasminogen activator inhibitor 1 (PAI-1), in SLE patients with clinically verified neuropsychiatric involvement and to compare these levels with those in SLE patients without neuropsychiatric involvement and in healthy subjects. METHODS: Levels of uPA, tPA, and PAI-1 were assessed in CSF from 94 patients with SLE (33 who had NPSLE, 56 who did not have NPSLE, and 5 who were positive for antiphospholipid antibody [not included in the NPSLE or non-NPSLE group]) and from 53 age-matched controls. Patients were evaluated clinically, with magnetic resonance imaging of the brain, analyses of neuronal/glial degradation products in CSF, and neuropsychiatric testing. RESULTS: In the group of patients with NPSLE, intrathecal PAI-1 levels were significantly elevated compared with levels in SLE patients without overt neuropsychiatric involvement (P < 0.05) and in healthy controls (P < 0.001). In contrast, intrathecal levels of uPA did not differ significantly. Intrathecal levels of PAI-1 correlated significantly with CSF levels of interleukin-6 (IL-6) (r = 0.34, P < 0.001) and IL-8 (r = 0.33, P < 0.001). Importantly, increased PAI-1 and D-dimer levels were observed in SLE patients who had pathologically elevated levels of glial fibrillary acidic protein, neurofilament triplet protein, and tau protein in CSF. CONCLUSION: Intrathecal release of PAI-1 is increased in patients with NPSLE. This results in impaired fibrinolysis, which might contribute to neuronal and astrocytic damage in NPSLE.

Plasminogen activator inhibitor-1: defining characteristics in the cerebrospinal fluid of newborns.

We measured plasminogen activator inhibitor-1 levels in the cerebrospinal fluid and plasma of newborns with and without posthemorrhagic hydrocephalus. We found that plasminogen activator inhibitor-1 levels in the cerebrospinal fluid of healthy newborns are <10 mg/mL but are greatly elevated in patients who have posthemorrhagic hydrocephalus and correlate directly with cerebrospinal fluid D-dimer and protein levels.

Plasminogen activator inhibitor 1, the primary regulator of fibrinolysis, in normal human cerebrospinal fluid.

The occurrence of type-1 plasminogen activator inhibitor (PAI-1) in human cerebrospinal fluid (CSF) has not previously been reported. As a member of the serpin superfamily of serine protease inhibitors and an acute phase response component, PAI-1 has powerful potential roles in nervous system homeostasis. We have detected this serpin antigen using a polyclonal anti-PAI-1 antibody in normal human CSF. In Western blotting, PAI-1 in several CSF samples appears as a two-band antigen of Mr = 54 and 35 kDa, presumably the intact and proteolytic fragment, respectively. In vitro complex formation studies confirm that the 54 kDa form of PAI-1 interacts with 125I-urokinase after activation with SDS, but the 35 kDa form does not. Quantification of total PAI-1 antigen in 18 normal human CSF samples by ELISA reveals a mean value of 1.0 +/- 0.07 (SEM) micrograms/dL, indicating that a relatively low concentration of the inhibitor occurs in normal human CSF. This information should now allow comparison of PAI-1 levels and activity in various neurologic disorders.

Cerebrospinal fluid plasminogen activator inhibitor-1: a prognostic factor in posthaemorrhagic hydrocephalus.

Intraventricular fibrinolytic enhancement with plasminogen activators is an experimental treatment for posthaemorrhagic hydrocephalus, but some infants do not respond. The objectives of this study were to investigate whether plasminogen activator inhibitor-1 is detectable in normal or posthaemorrhagic neonatal cerebrospinal fluid and whether higher neonatal cerebrospinal fluid concentrations of plasminogen activator inhibitor-1 are associated with failure of fibrinolytic therapy. Cerebrospinal fluid samples from 7 controls and 16 infants with posthaemorrhagic hydrocephalus (15 treated with exogenous fibrinolytic agents) were analysed for plasminogen activator inhibitor-1. Plasminogen activator inhibitor-1 was not detectable in any of the control samples but was detectable in all but one of the posthaemorrhagic samples, and at significantly higher levels in the treatment failures (median 94 ng ml(-1)) than in the treatment successes (median 25 ng ml(-1)). High levels of plasminogen activator inhibitor-1 in the cerebrospinal fluid are predictive of, and provide a plausible biological explanation for, failure of intraventricular fibrinolytic therapy.