Jasone Monasterio

Matrix Metalloproteinase-9 Pretreatment Level Predicts Intracranial Hemorrhagic Complications After Thrombolysis in Human Stroke

Background—Matrix metalloproteinase (MMP) expression is related to blood brain barrier disruption after cerebral ischemia. Moreover, MMP inhibitors reduce hemorrhagic transformation (HT) after embolic ischemia in tissue plasminogen activator (t-PA)–treated animals. We aimed to correlate plasmatic MMP levels with the appearance of intracranial bleeding complications in stroke patients treated with t-PA. Methods and Results—Serial MMP-2 and MMP-9 determinations were performed (ELISA, ng/mL) in 41 strokes involving the middle cerebral artery territory in patients who received t-PA within 3 hours of stroke onset. Blood samples were obtained at baseline (pretreatment) and at 12 and 24 hours after symptom onset. Hemorrhagic events were classified according to CT criteria (petechial hemorrhagic infarctions [HI, 1 to 2] and large parenchymal hemorrhages [PH, 1 to 2]). Brain CT scan was obtained at 48 hours or when a neurological worsening occurred. HT was present in 36.5% of the patients (24.4% HI and 12.1% PH). MMP-2 values were unrelated to any subtype of HT. The highest baseline MMP-9 level (normal range <97 ng/mL) corresponded to patients who later developed a PH (PH: 270.2±87.8, non-HT: 126.3±127.5, HI: 94.6±88.7;P =0.047). A graded response was found between mean baseline MMP-9 levels and the degree of bleeding (HI-1=37.4; HI-2=111.0; PH-1=202.5; PH-2=337.8). Baseline MMP-9 was the most powerful predictor of PH appearance in the multiple logistic regression model (OR= 9.62; CI 1.31 to 70.26;P =0.025). Conclusions—Baseline MMP-9 level predicts PH appearance after t-PA treatment. Therefore, we suggest that MMP determination may increase the safety profile for thrombolysis and, in the future, anti-MMP drugs might be combined with t-PA to prevent hemorrhagic complications.

Matrix Metalloproteinase Expression After Human Cardioembolic Stroke Temporal Profile and Relation to Neurological Impairment

Background and Purpose— Uncontrolled expression of matrix metalloproteinases (MMPs) can result in tissue injury and inflammation. In animal models of cerebral ischemia, the expression of MMP-2 and MMP-9 was significantly increased. However, their role in human stroke in vivo remains unknown. Therefore, we sought to determine the temporal profile of MMP expression in patients with acute ischemic stroke and to investigate its relationship to stroke severity, location of arterial occlusion, and total infarct volume. Methods— Serial MMP-2 and MMP-9 determinations were made in 39 patients with cardioembolic strokes that involved the middle cerebral artery territory by means of enzyme-linked immunosorbent assay. Blood samples, transcranial Doppler recordings, and National Institutes of Health Stroke Scale (NIHSS) scores were obtained at baseline and at 12, 24, and 48 hours after stroke onset. Infarct volume was measured with CT scanning at 48 hours. Results— No correlation was found between MMP-2 and NIHSS score at any time point, although a close relation appeared between mean MMP-9 and final NIHSS score (r =0.486, P =0.002). MMP-9 value was the only factor associated with the final NIHSS score in the multiple logistic regression model (OR 4.54, 95% CI 1.5 to 13.75). A cut-point of MMP-9 142.18 ng/mL had a positive predictive value of 94.4% to assess a patient’s NIHSS (<8 or ≥8) by the end of the study. Final MMP-2 and MMP-9 levels were significantly lower when recanalization occurred (528±144.3 versus 681.4±239.2 ng/mL, P =0.031 for MMP-2; 110.2±100.9 versus 244.8±130 ng/mL, P =0.004 for MMP-9). A positive correlation was found between mean MMP-9 and infarct volume (r =0.385, P =0.022). Conclusions— MMPs are involved in the acute phase of human ischemic stroke. MMP-9 levels are associated with neurological deficit, middle cerebral artery occlusion, and infarct volume.

Plasmatic level of neuroinflammatory markers predict the extent of diffusion-weighted image lesions in hyperacute stroke.

Sixteen patients with acute middle cerebral artery stroke were studied to correlate neuroinflammatory markers with perfusion- and diffusion-weighted magnetic resonance imaging (MRI) lesion volumes (PWI and DWI). At arrival (less than 6 hours), plasmatic matrix metalloproteinase (MMP)-9, MMP-2, interleukin (IL)-6, IL-8, intercellular adhesion molecule (ICAM)-1, and tumor necrosis factor (TNF)-α were serially measured (by ELISA), and MRI was performed. In cerebral ischemia, tissue destruction seems related to matrix metalloproteinases expression because baseline MMP-9 was the only predictor of the infarct volume measured as a DWI lesion (lineal regression: b = 0.50, 0.25–0.74; P < 0.001). Moreover, the extent of hypoperfused brain area (PWI) was associated with a proinflammatory cytokine release in the next hours (TNF-α and IL-6).

Thrombin-Activable Fibrinolysis Inhibitor Levels in the Acute Phase of Ischemic Stroke

Background and Purpose— Thrombin-activable fibrinolysis inhibitor (TAFI) is a recently identified fibrinolysis inhibitor in plasma. The purpose of this work was to study TAFI levels in the acute phase of ischemic stroke and their relationship with stroke evolution. Methods— In 30 consecutive ischemic stroke patients, TAFI plasma levels were measured by means of enzyme-linked immunosorbent assay (percentage of the pooled reference kit expressed as mean±SD) and compared with the values obtained in 30 healthy control subjects. All samples were drawn within the first 24 hours after symptom onset (mean, 4.6 hours) and before any treatment was started. Results— TAFI plasma concentration was significantly higher (P <0.001) in stroke patients (158.4±53.2%) than in healthy control subjects (105.6±30.2%). The highest TAFI levels were found in cases of neurological deterioration (worsening, 198.1±63.0%; stability, 130.5±39.3%; improvement, 173.9±52.0%;P =0.057). Conclusions— High levels of TAFI are found in the acute phase of ischemic stroke.

Tissue factor levels and high ratio of fibrinopeptide A:D-dimer as a measure of endothelial procoagulant disorder in pre-eclampsia

To assess coagulation activation and endothelial cell injury in normotensive and pre‐eclamptic pregnant women, a comparision was made of plama levels of tissue factor, fibronectin, fibrinopeptide A and D‐dimer. Samples were taken from 50 nonpregnant women, 40 normotensive pregnant women in the third trimester and 27 women with pre‐eclampsia after diagnosis and before treatment. High levels of fibrinopeptide A and D‐dimer were found in pre‐eclampsia women. Moreover, the ratio fibrinopeptide A:D‐dimer was much greater in the pre‐eclampsia group than in normotensive pregnant women. The levels of fibronectin and tissue factor were also higher in the pre‐eclampsia group. The increase of tissue factor levels suggests an alteration of the extrinsir coagulation pathway in pre‐eclampsia. The increase of fibrinopeptide A:D dimer ratio shows that the activation of coagulation is associated with a relative hypofibrinolysis in pre‐eclampsia.

Endothelial cell markers and fibrinopeptide A to D-dimer ratio as a measure of coagulation and fibrinolysis balance in normal pregnancy

Objective: Changes in hemostatic system were evaluated in healthy pregnant women. Methods: Blood was sampled in the 1st, 2nd and 3rd trimesters of gestation, during delivery and 3 days postpartum and plasma factors were measured using commercial tests. Results: Thrombin-antithrombin III complexes, fibrinopeptide A and D-dimer were higher during pregnancy. The endothelial cell markers, fibronectin and tissue factor, remained within the normal reference values in the healthy nonpregnant population. This result suggests no endothelial injury and shows no activation of extrinsic coagulation pathway during pregnancy. The balance coagulation/fibrinolysy is maintained during pregnancy and delivery, as shown by the ratio fibrinopeptide A/D-dimer, however, a tendency towards coagulation process is developed in the early puerperium.

Evaluation of thrombin-antithrombin complexes and fibrin fragment D in carbohydrate-induced acute laminitis.

Carbohydrate-induced laminitis has been associated with decreased platelet survival, decreased blood flow to the hoof wall and with the deposition of platelets and microthrombi within venules in the dermal laminae. To evaluate further the systemic prothrombotic events occurring in the prodromal stages of laminitis, plasma samples from control and laminitis-affected ponies and horses were tested for the presence of thrombin-antithrombin (TAT) complexes and fibrin fragment D (D-dimer). No statistically significant differences between the control and laminitis-affected animals were observed for either the D-dimer or the TAT complexes. Few of the values for individual animals exceeded the reference ranges for control animals. These data indicate that the prothrombotic events observed in carbohydrate-induced laminitis may not be associated with systemic activation of the coagulation or fibrinolytic systems.

Comparative Study on the Antithrombotic Efficacy of Four Low-Molecular-Weight Heparins in Three Different Models of Experimental Venous Thrombosis

In a randomized, blind study, both the antithrombotic efficacy (reduction of thrombus weight) and potency (anti-Xa activity) of several commercially available low-molecular-weight heparins (LMWHs) were compared with those of unfractioned heparin (UFH) and placebo. Three different thrombogenic challenges were used: venous thrombosis was induced by direct endothelial damage in 60 New Zealand rabbits (group I), intracarotid injection of bovine thrombin in an additional series of 60 rabbits (group II), or after inferior-vena-cava ligature in 60 Wistar rats (group III). The drugs were administered subcutaneously 2 h before surgery in a blind fashion. The doses recommended for clinical practice were used (adjusted by body weight), except in group II animals, in whom doses were doubled. No differences were found between UFH and most LMWHs in terms of reduction of thrombus weight in group I animals. But UFH showed a weaker antithrombotic efficacy in the other two models. Similarly, one of the LMWHs used (Clexane) proved to be not as effective as the remainder. However, only clinical studies will provide enough information to verify these differences. Additionally, our findings confirm that the antithrombotic efficacy of a given drug differs according to the stimulus used to induce venous thrombosis.

Plasma thrombin-activatable fibrinolytic inhibitor (TAFI) among healthy subjects and patients with vascular diseases: a validation study.

Thrombin activable fibrinolysis inhibitor antigen levels (TAFI Ag ) exhibit a great inter-individual variability in healthy populations. Our aim is to determine whether variability is due to physiologic variations depending on genetic control or due to validation of the method,in order to allow a better interpretation of the results inpatients with vascular diseases. With this purpose, we performed a strategy validation of specific ELISA method, Zymutest TAFI Ag Hyphen Biomed, base don a commercial monoclonal antibody. After methodology validation we have recently determined plasma TAFI Ag levels in several groups of diseases such as septic patients, menopause and cerebrovascular diseases. TAFI was finally determined in acute ischemic stroke to know its relationship with stroke evolution and response to thrombolytic treatments.

Comparative study on the antithrombotic efficacy of hirudin, heparin and a low-molecular weight heparin in preventing experimentally induced venous thrombosis.

In a random, blind study, we compared the antithrombotic potential of unfractioned heparin, a low-molecular weight heparin (LMWH) and a recombinant hirudin (r-hirudin) given subcutaneously in a jugular vein thrombosis model in rabbits. All drugs and placebo were injected subcutaneously 2 h before inducing experimental thrombosis. A good thromboprophylactic effect was obtained with either LMWH and r-hirudin as compared with placebo. By contrast, no significant differences were found between groups in bleeding time. We also found a small (non-significant) prolongation of the activated partial thromboplastin time in the r-hirudin-treated animals. As for thrombin time, r-hirudin-treated rabbits exhibited too much sensitivity, with noncoagulable end-points. In our study, r-hirudin at the dose used seemed to be as effective as LMWH is in the prophylaxis of venous thrombosis.