Natural anticoagulants (antithrombin III, protein C, and protein S) in patients with mild to moderate ischemic stroke

Sex Differences in Hemostatic Factors in Patients With Ischemic Stroke and the Relation With Migraine-A Systematic Review

Background: Women are more affected by stroke than men. This might, in part, be explained by sex differences in stroke pathophysiology. The hemostasis system is influenced by sex hormones and associated with female risk factors for stroke, such as migraine.

Aim: To systematically review possible sex differences in hemostatic related factors in patients with ischemic stroke in general, and the influence of migraine on these factors in women with ischemic stroke.

Results: We included 24 studies with data on sex differences of hemostatic factors in 7247 patients with ischemic stroke (mean age 57–72 years, 27–57% women) and 25 hemostatic related factors. Levels of several factors were higher in women compared with men; FVII:C (116% ± 30% vs. 104% ± 30%), FXI (0.14 UI/mL higher in women), PAI-1 (125.35 ± 49.37 vs. 96.67 ± 38.90 ng/mL), D-dimer (1.25 ± 0.31 vs. 0.95 ± 0.24 μg/mL), and aPS (18.7% vs. 12.0% positive). In contrast, protein-S (86.2% ± 23.0% vs. 104.7% ± 19.8% antigen) and P-selectin (48.9 ± 14.4 vs. 79.1 ± 66.7 pg/mL) were higher in men. Most factors were investigated in single studies, at different time points after stroke, and in different stroke subtypes. Only one small study reported data on migraine and hemostatic factors in women with ischemic stroke. No differences in fibrinogen, D-dimer, t-PA, and PAI-1 levels were found between women with and without migraine.

Conclusion: Our systematic review suggests that sex differences exist in the activation of the hemostatic system in ischemic stroke. Women seem to lean more toward increased levels of procoagulant factors whereas men exhibit increased levels of coagulation inhibitors. To obtain better insight in sex-related differences in hemostatic factors, additional studies are needed to confirm these findings with special attention for different stroke phases, stroke subtypes, and not in the least women specific risk factors, such as migraine.

Immune-inflammatory, coagulation, adhesion, and imaging biomarkers combined in machine learning models improve the prediction of death 1 year after ischemic stroke

Some clinical, imaging, and laboratory biomarkers have been identified as predictors of prognosis of acute ischemic stroke (IS). The aim of this study was to evaluate the prognostic validity of a combination of clinical, imaging, and laboratory biomarkers in predicting 1-year mortality of IS. We evaluated 103 patients with IS within 24 h of their hospital admission and assessed demographic data, IS severity using the National Institutes of Health Stroke Scale (NIHSS), carotid intima-media thickness (cIMT), and degree of stenosis, as well as laboratory variables including immune-inflammatory, coagulation, and endothelial dysfunction biomarkers. The IS patients were categorized as survivors and non-survivors 1 year after admission. Non-survivors showed higher NIHSS and cIMT values, lower antithrombin, Protein C, platelet counts, and albumin, and higher Factor VIII, von Willebrand Factor (vWF), white blood cells, tumor necrosis factor (TNF)-α, interleukin (IL)-10, high-sensitivity C-reactive protein (hsCRP), and vascular cellular adhesion molecule 1 (VCAM-1) than survivors. Neural network models separated non-survivors from survivors using NIHSS, cIMT, age, IL-6, TNF-α, hsCRP, Protein C, Protein S, vWF, and platelet endothelial cell adhesion molecule 1 (PECAM-1) with an area under the receiving operating characteristics curve (AUC/ROC) of 0.975, cross-validated accuracy of 93.3%, sensitivity of 100% and specificity of 85.7%. In conclusion, imaging, immune-inflammatory, and coagulation biomarkers add predictive information to the NIHSS clinical score and these biomarkers in combination may act as predictors of 1-year mortality after IS. An early prediction of IS outcome is important for personalized therapeutic strategies that may improve the outcome of IS.

Scalable Bio Marker Combinations for Early Stroke Diagnosis: A Systematic Review

Background: Acute stroke treatment is a time-critical process in which every minute counts. Laboratory biomarkers are needed to aid clinical decisions in the diagnosis. Although imaging is critical for this process, these biomarkers may provide additional information to distinguish actual stroke from its mimics and monitor patient condition and the effect of potential neuroprotective strategies. For such biomarkers to be effectively scalable to public health in any economic setting, these must be cost-effective and non-invasive. We hypothesized that blood-based combinations (panels) of proteins might be the key to this approach and explored this possibility through a systematic review. Methods: We followed the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) guidelines for systematic review. Initially, the broader search for biomarkers for early stroke diagnosis yielded 704 hits, and five were added manually. We then narrowed the search to combinations (panels) of the protein markers obtained from the blood. Results: Twelve articles dealing with blood-based panels of protein biomarkers for stroke were included in the systematic review. We observed that NR2 peptide (antibody against the NR2 fragment) and glial fibrillary acidic protein (GFAP) are brain-specific markers related to stroke. Von Willebrand factor (vWF), matrix metalloproteinase 9 (MMP-9), and S100β have been widely used as biomarkers, whereas others such as the ischemia-modified albumin (IMA) index, antithrombin III (AT-III), and fibrinogen have not been evaluated in combination. We herein propose the following new combination of biomarkers for future validation: panel 1 (NR2 + GFAP + MMP-9 + vWF + S100β), panel 2 (NR2 + GFAP + MMP-9 + vWF + IMA index), and panel 3 (NR2 + GFAP + AT-III + fibrinogen). Conclusions: More research is needed to validate, identify, and introduce these panels of biomarkers into medical practice for stroke recurrence and diagnosis in a scalable manner. The evidence indicates that the most promising approach is to combine different blood-based proteins to provide diagnostic precision for health interventions. Through our systematic review, we suggest three novel biomarker panels based on the results in the literature and an interpretation based on stroke pathophysiology.

Antithrombin gamma attenuates macrophage/microglial activation and brain damage after transient focal cerebral ischemia in mice

AIMS

Thrombin formation is increased in patients with acute cerebral ischemic stroke, and augments coagulation and inflammation in the brain. Administration of antithrombin (AT) was previously reported to be protective against renal and myocardial ischemic injury. Thus, we hypothesized that treatment with AT would be neuroprotective against cerebral ischemic injury. This study evaluated the effects of AT treatment on ischemic inflammation and brain damage in mice subjected to middle cerebral artery occlusion (MCAO).

MAIN METHODS

A mouse model of 4-hour MCAO was used to induce ischemic brain injury. Recombinant AT gamma was administered intravenously immediately after reperfusion at 4 h after MCAO. Infarct volume, neurological deficit, and regional cerebral blood flow (rCBF) were measured at 24 h after MCAO. To evaluate the effect of AT gamma on ischemic inflammation, we measured the number of Iba1-positive cells (marker of macrophage/microglial activation) and levels of proinflammatory cytokines. Further, we investigated the direct anti-inflammatory effects of rAT in the J774.1 cell line.

KEY FINDINGS

Treatment with AT gamma (480 U/kg) reduced infarct volume and neurological deficit, and improved rCBF, in MCAO mice. Moreover, AT gamma treatment decreased the number of Iba1-positive cells and levels of proinflammatory cytokines. In vitro, treatment with thrombin significantly increased proinflammatory cytokine levels, which was significantly reduced by pretreatment with AT gamma.

SIGNIFICANCE

Treatment with AT showed neuroprotective effects via anticoagulation actions, as well as direct anti-inflammatory effects on macrophage/microglial activation. These data suggest that AT may be a useful new therapeutic option for cerebral ischemia.

Prognostic Hemostasis Biomarkers in Acute Ischemic Stroke

Supplemental Digital Content is available in the text.

Objectives—

The prediction of patients at risk for poor clinical outcome after acute ischemic stroke remains challenging. An imbalance of coagulation factors may play an important role in progression and prognosis of these patients. In this systematic review, we assessed the current literature on hemostasis biomarkers and the association with poor clinical outcome in acute ischemic stroke.

Approach and Results—

A systematic search of Embase, Medline, Cochrane Library, Web of Science, and Google Scholar was performed on studies reporting on hemostasis biomarkers and clinical outcome after acute ischemic stroke. Studies were considered eligible if blood samples were collected within 72 hours after symptom onset. Additionally, clinical outcome should be assessed using a disability score (Barthel Index or modified Rankin scale). Methodological quality of included studies was assessed with an adapted version of the Quality Assessment of Diagnostic Accuracy Studies questionnaire. A total of 80 articles were read full text, and 41 studies were considered eligible for inclusion, reporting on 37 different hemostasis biomarkers. No single biomarker appeared to be effective in predicting poor clinical outcome in acute ischemic stroke patients.

Conclusions—

Based on current literature, no clear recommendations can be provided on which hemostasis biomarkers are a predictor of clinical outcome after acute ischemic stroke. However, some biomarkers show promising results and need to be further investigated and validated in large populations with clear defined study designs.

Predictors of stroke outcome: the role of hemorheology, natural anticoagulants, and serum albumin

BACKGROUND

The early hours after an acute stroke are crucial; early accurate prediction of outcome in stroke patients can help health system providers and families to choose appropriate lines of management and plan for the future. The aim of this work is to assess the role of hemorheological parameters (such as blood viscosity, hematocrit, platelet aggregation, and leukocyte count), protein C, protein S, antithrombin III, and serum albumin as predictors of stroke outcome.

METHODS

Thirty subjects, 20 patients with acute ischemic stroke within 24 h from the onset and 10 normal subjects, were included in this case control study. Clinical, functional, and radiological evaluation was done for the patients, and all patients and control were subjected to routine laboratory tests and assessment of blood viscosity, hematocrit level, platelet aggregation, protein C, protein S, and antithrombin III.

RESULTS

Platelet aggregation was significantly higher and serum albumin was significantly lower in stroke patients compared to control (p value = 0.000 and 0.039) respectively. On comparing between patient with good and poor outcome, good outcome was associated with increased serum albumin level at admission (p value = 0.03) respectively. A significant negative correlation was found between total leukocyte count, hematocrit value, and stroke outcome (p value = 0.015 and 0.013) respectively. Only albumin was found to be a significant predictor for outcome by linear regression analysis.

CONCLUSION

Serum albumin, hematocrit level, and total leukocyte count at the time of presentation of ischemic stroke are useful markers for stroke outcome.

Plasma factor and inhibitor composition contributes to thrombin generation dynamics in patients with acute or previous cerebrovascular events

INTRODUCTION

More than 80% of cerebrovascular events are ischemic and largely thromboembolic by nature. We evaluated whether plasma factor composition and thrombin generation dynamics might be a contributor to the thrombotic phenotype of ischemic cerebrovascular events.

MATERIALS AND METHODS

We studied (1) 100 patients with acute ischemic stroke (n=50) or transient ischemic attack (TIA) (n=50) within the first 24 hours from symptom onset, and (2) 100 individuals 1 to 4 years following ischemic stroke (n=50) or TIA (n=50). The tissue factor pathway to thrombin generation was simulated with a mathematical model using plasma levels of clotting factors (F)II, V, VII, VIII, IX, X, antithrombin and free tissue factor pathway inhibitor (TFPI).

RESULTS

The plasma levels of free TFPI, FII, FVIII, and FX were higher, while antithrombin was lower, in the acute patients compared to the previous event group (all p≤0.02). Thrombin generation during acute events was enhanced, with an 11% faster maximum rate, a 15% higher maximum level and a 26% larger total production (all p<0.01). The increased thrombin generation in acute patients was determined by higher FII and lower antithrombin, while increased free TFPI mediated this effect. When the groups are classified by etiology, all stroke sub-types except cardioembolic have increased TFPI and decreased AT and total thrombin produced.

CONCLUSION

Augmented thrombin generation in acute stroke/TIA is to some extent determined by altered plasma levels of coagulation factors.

Thrombin antithrombin complex and IL-18 serum levels in stroke patients

The complex picture of inflammation and coagulation alterations comes to life in acute stroke phases. Increasing evidence points to a strong interaction and extensive crosstalk between the inflammation and coagulation systems: the interest towards this relationship has increased since recent experimental research showed that the early administration of antithrombin III (ATIII) decreases the volume of ischemia in mice and might be neuroprotective, playing an antiinflammatory role.

We aimed to establish the extent of the relationship among markers of inflammation (S100B and IL-18) and procoagulant and fibrinolytic markers (ATIII, thrombin-antithrombin III complex (TAT), Fibrin Degradation Products (FDP), D-dimer) in 13 comatose patients affected by focal cerebral ischemia.

Plasma levels of TAT, D-dimer and FDP, IL18 and S100B were increased. IL-18 and S100B high serum levels in ischemic patients suggest an early activation of the inflammatory cascade in acute ischemic injury.

The basic principles of the interaction between inflammatory and coagulation systems are revised, from the perspective that simultaneous modulation of both coagulation and inflammation, rather than specific therapies aimed at one of these systems could be more successful in stroke therapy.

Blood markers for the prognosis of ischemic stroke: a systematic review

BACKGROUND AND PURPOSE

The performance of validated prognostic clinical models in acute ischemic stroke might be improved by addition of data on blood biomarkers.

METHODS

We searched Medline and EMBASE from 1966 to January 2007 for studies of blood markers in patients with ischemic stroke and an assessment of outcome (death, disability, or handicap). We adopted several strategies to reduce bias.

RESULTS

Studies were generally small (median number of subjects, 85; interquartile range, 49 to 184). Few had evidence of a sample size calculation (7 of 82 [9%]) or reported blinding to whether patients had stroke (21 of 82 [26%]). Of the 66 studies reporting a measure of association, 10 did not adjust for age or stroke severity, 14 adjusted for age, 7 adjusted for severity, and 35 adjusted for both; 30% (20 of 66) used a data-dependent threshold to predict good or bad outcome. There was evidence of within-study reporting bias and publication bias. Cardiac markers showed the most consistent association with poor outcome.

CONCLUSIONS

Blood biomarkers might provide useful information to improve the prediction of outcome after acute ischemic stroke. However, this review showed that many studies were subject to bias. Although some markers had some predictive ability, none of the studies was able to demonstrate that the biomarker added predictive power to a validated clinical model. The clinical usefulness of blood biomarkers for predicting prognosis in the setting of ischemic stroke has yet to be established.

Antithrombin reduces ischemic volume, ameliorates neurologic deficits, and prolongs animal survival in both transient and permanent focal ischemia

BACKGROUND AND PURPOSE

Antithrombin (AT), a glycoprotein belonging to the serpin family, blocks thrombin formation and activity at several steps. Thrombin, beside its relevant role in the coagulation cascade, exerts neurodetrimental effects through the activation of a family of protease-activated receptors, which can be implicated in stroke pathophysiology. The aims of the present study were to evaluate whether AT could reduce brain damage, ameliorate neurologic deficits, and prolong animal survival.

METHODS

Two different doses of AT (10 and 30 IU/kg IP) were administered 3 hours, 6 hours, or 3 and 6 hours after an ischemic insult to mice and rats subjected to either transient or permanent focal ischemia. Ischemic volume was evaluated 24 hours or 7 days after the ischemic insult. Neurologic deficits were also scored.

RESULTS

In mice, 10 or 30 IU/kg AT administered twice, at 3 and 6 hours after transient ischemia, and 30 IU/kg AT administered 3 hours only after transient ischemia substantially reduced total ischemic volume, significantly improved neurologic deficits evaluated 24 hours after the insult, and prolonged animal survival. In rats, the same doses given at the same time intervals significantly reduced ischemic volume, evaluated 24 hours after permanent ischemia.

CONCLUSIONS

These results indicate that AT remarkably reduces infarct volume, ameliorates neurologic deficit scores, and prolongs animal survival in 2 rodent models of brain ischemia. Taken together, our data suggest that AT, delivered via systemic administration, an easily achievable route of administration and in a clinically useful time window, could represent a new therapeutic strategy to be validated for the clinical treatment of human stroke.

Serial measurements of plasma homocysteine levels in early and late phases of ischemic stroke

High plasma levels of homocysteine (Hcy) may predispose to ischemic stroke (IS), but results of previous studies have been conflicting. We decided to determine in IS patients whether their Hcy levels are elevated, whether levels vary at different time points following stroke, whether levels are associated with stroke severity, outcome, recurrence, etiology, infarct volume, or risk factors, and whether levels are correlated with hemostatic factors or C-reactive protein values. We measured plasma Hcy levels in 102 consecutive IS patients on admission and at 1 week, 1 month, and 3 months after stroke and once in 102 control subjects. Hemostatic factors were measured in 55 patients. Compared with controls, plasma Hcy levels in patients were significantly lower on admission but not at later time points, with levels increasing by week and remaining at this level for 3 months. Hcy levels showed a positive correlation with age and a negative correlation with Mini-Mental State Examination (MMSE) scores. Plasma Hcy levels inversely correlated with plasminogen activator inhibitor type-1. Decreased Hcy levels on admission may reflect the strength of the acute-phase response rather than a pathogenetic event. The negative correlation between Hcy levels and MMSE scores is more probably age-related than stroke-related.

The relationship between protein C, protein S and cytokines in acute ischemic stroke

OBJECTIVE

The role of inflammation in the pathogenesis of acute ischemic stroke is well known, but its association with the clinical picture is as yet unclear.

MATERIAL AND METHODS

In our study, we measured the serum levels of the proinflammatory cytokines interleukin-1beta (IL-1beta), tumor necrosis factor alpha (TNFalpha) and interleukin-6 (IL-6) within the first 50 h of stroke in 60 acute stroke patients, and examined the association with the natural anticoagulants protein C and free protein S. We compared the results with a control group that consisted of 30 volunteers. We also correlated their levels with the clinical outcomes by using the Canadian Neurological Scale (CNS).

RESULTS

Neither stroke patients nor the control group had any elevations in IL-1beta serum levels. However, the levels of serum IL-6 were significantly higher in stroke patients (13.7 +/- 19.46 vs. 4.3 +/- 15.88, p = 0.002). In addition, the protein S levels of patients were lower than those of the controls (84.36 +/- 27.97 vs. 95.9 +/- 25.64, p = 0.007). Although IL-6 showed negative correlation with protein S (r = -0.504, p = 0.000), the other studied cytokines TNFalpha and IL-1beta did not correlate with these natural anticoagulants. Another negative correlation was found between IL-6 and CNS scores (r = -0.451, p = 0.000). In addition, both protein C and protein S positively correlated with CNS (r = 0.263, p = 0.042; r = 0.381, p = 0.003). There was also a positive correlation between protein C and protein S (r = 0.408, p = 0.001).

CONCLUSIONS

Our results suggest that TNFalpha and IL1beta serum levels are not elevated in the acute phase of stroke and have no correlation with the natural anticoagulants protein C and protein S. However, a decrease in free protein S may be related to elevated IL-6 levels. In addition, increased levels of IL-6 and reduced levels of protein C and protein S may play a role in acute ischemic stroke severity.