Dysregulation of lysophosphatidic acids in multiple sclerosis and autoimmune encephalomyelitis.

Bioactive lipids contribute to the pathophysiology of multiple sclerosis. Here, we show that lysophosphatidic acids (LPAs) are dysregulated in multiple sclerosis (MS) and are functionally relevant in this disease. LPAs and autotaxin, the major enzyme producing extracellular LPAs, were analyzed in serum and cerebrospinal fluid in a cross-sectional population of MS patients and were compared with respective data from mice in the experimental autoimmune encephalomyelitis (EAE) model, spontaneous EAE in TCR1640 mice, and EAE in Lpar2 -/- mice. Serum LPAs were reduced in MS and EAE whereas spinal cord LPAs in TCR1640 mice increased during the 'symptom-free' intervals, i.e. on resolution of inflammation during recovery hence possibly pointing to positive effects of brain LPAs during remyelination as suggested in previous studies. Peripheral LPAs mildly re-raised during relapses but further dropped in refractory relapses. The peripheral loss led to a redistribution of immune cells from the spleen to the spinal cord, suggesting defects of lymphocyte homing. In support, LPAR2 positive T-cells were reduced in EAE and the disease was intensified in Lpar2 deficient mice. Further, treatment with an LPAR2 agonist reduced clinical signs of relapsing-remitting EAE suggesting that the LPAR2 agonist partially compensated the endogenous loss of LPAs and implicating LPA signaling as a novel treatment approach. Graphical summary of lysophosphatidic signaling in multiple sclerosis.

[Direct oral anticoagulants and acute stroke : Insights into translational research studies]. / Direkte orale Antikoagulanzien und akuter Schlaganfall : Einblicke in translationale Forschungsarbeiten.

In recent years a considerable number of translational research studies on intracerebral hemorrhage and ischemic stroke have been published, which are characterized by a particular proximity to practical clinical questions. Animal research has provided insights into the pathophysiological processes and therapy effects, which have so far only been insufficiently investigated in clinical studies. This includes the effectiveness of a rapid reversal of anticoagulation in cases of anticoagulation-associated intracerebral hemorrhage and the safety of thrombolytic treatment in ischemic stroke occurring during treatment with anticoagulants. With the approval of the direct oral anticoagulants these problems have become of particular contemporary relevance. Of course, results from experimental translational studies on stroke cannot be directly translated into clinical routine. Nevertheless, these investigations help to understand the underlying processes and mechanisms and provide proof of concept data for new treatment strategies. This review summarizes the most relevant results in this field of research with a particular focus on practical clinical questions.

Alterations of the Ceramide Metabolism in the Peri-Infarct Cortex Are Independent of the Sphingomyelinase Pathway and Not Influenced by the Acid Sphingomyelinase Inhibitor Fluoxetine.

Ceramides induce important intracellular signaling pathways, modulating proliferation, migration, apoptosis, and inflammation. However, the relevance of the ceramide metabolism in the reconvalescence phase after stroke is unclear. Besides its well-known property as a selective serotonin reuptake inhibitor, fluoxetine has been reported to inhibit the acid sphingomyelinase (ASM), a key regulator of ceramide levels which derives ceramide from sphingomyelin. Furthermore, fluoxetine has shown therapeutic potential in a randomized controlled rehabilitation trial in stroke patients. Our aim was to investigate and modulate ceramide concentrations in the peri-infarct cortex, whose morphological and functional properties correlate with long-term functional outcome in stroke. We show that certain ceramide species are modulated after experimental stroke and that these changes do not result from alterations of ASM activity, but rather from nontranscriptional induction of the ceramide de novo pathway. Unexpectedly, although reducing lesion size, fluoxetine did not improve functional outcome in our model and had no significant influence on ASM activity or the concentration of ceramides. The ceramide metabolism could emerge as a potential therapeutic target in the reconvalescence phase after stroke, as its accumulation in the peri-infarct cortex potentially influences membrane functions as well as signaling events in the tissue essential for neurological recovery.

[Glial fibrillary acidic protein in patients with symptoms of acute stroke: diagnostic marker of cerebral hemorrhage]. / Saures Gliafaserprotein beim Patienten mit akuten Schlaganfallsymptomen : Diagnostischer Marker einer Hirnblutung.

Glial fibrillary acidic protein (GFAP) is a highly brain-specific protein that is expressed in large quantities in astrocytes and has important functions in terms of maintaining and stabilizing the cytoskeleton. Acute intracerebral hemorrhage leads to an immediate mechanical destruction of astroglial cells with the subsequent release of GFAP into the extracellular space and the bloodstream. On the other hand, necrosis, cytolysis and GFAP release does not occur before 6-12 h after symptom onset in ischemic stroke. Thus, in the early hours after stroke increased GFAP values could indicate intracerebral hemorrhage. This review article describes the underlying pathophysiology of the test and guides the reader through the available data. Potential implications regarding the prehospital triage of acute stroke patients are discussed, including the possibility to initiate hyperacute treatment, such as blood pressure reduction in patients with intracerebral hemorrhage. Other areas of interest for a potential GFAP test include traumatic brain injury and malignant gliomas.

Hematoma expansion in experimental intracerebral hemorrhage is not altered by peracute treatment with recombinant tissue plasminogen activator.

Recombinant tissue-type plasminogen activator (rt-PA) is the mainstay of acute stroke treatment and the only approved medical therapy so far. Because of its fibrinolytic action, it is presumed to aggravate intracerebral hemorrhage (ICH). Since clinical features do not discriminate between ischemic stroke and ICH, brain imaging is strictly required before the initiation of thrombolysis. A recent study has shown that rt-PA does not worsen (primary) ICH in two different experimental mouse models. Here, we further explored this surprising finding and examined hematoma expansion and long-term outcome after rt-PA treatment in a murine model of ICH. We induced ICH by collagenase injection into the right basal ganglia of C57BL/6 mice. At 30 min, 90 min or 4h after ICH induction, respectively, mice were treated with vehicle or 10mg/kg rt-PA. In parallel, we administered the vascular tracer Evans Blue (EB) and sacrificed the mice 2h after injection to assess EB extravasation as a marker of ongoing bleeding and rt-PA induced rebleeding. Additionally, we observed mice which were treated with vehicle or rt-PA 30 min after ICH induction for 72 h and quantified functional outcome and hematoma volume. EB extravasation was highest in the groups that were treated after 30 min and decreased thereafter according to a cessation of active bleeding. At all three time points covering the early phase of ICH, treatment with rt-PA did not increase EB extravasation. In the 72 h observation, there was also no difference in functional outcome and hematoma volume. In our experimental study, we were not able to demonstrate that peracute rt-PA treatment in (primary) ICH has detrimental effects on hematoma expansion, hematoma volume or functional outcome. This finding needs careful consideration in future translational studies.

Time trends in systemic thrombolysis in a large hospital-based stroke registry.

BACKGROUND: Systemic thrombolysis for acute stroke was approved by German authorities in 2002. While recombinant tissue plasminogen activator (rtPA) use first remained low, systemic thrombolysis is nowadays an established part of common stroke care. The purpose of this study was to determine changes in systemic thrombolysis rates within an observation period of 7 years following the approval of rtPA therapy in Germany in a large state-wide stroke data set. METHODS: We analyzed a prospective hospital-based stroke registry covering the entire federal state of Hesse, Germany. All hospitals providing stroke care in Hesse (neurology hospitals and hospitals for internal medicine) are obligated to register all inpatients. All cases admitted between 2003 and 2009 with a final diagnosis of ischemic stroke (ICD-10: I63) were selected. We analyzed the relationship between thrombolysis rates, onset-to-admission time (hospital arrival ≤3 and >3 h after symptom onset), patient age (quartiles and dichotomized in ≤80 and >80 years) and disability at admission (assessed by the Rankin Scale). A one-way ANOVA with Bonferroni correction for multiple comparisons was performed to test for significant changes during the observation period. RESULTS: 88,340 patients with ischemic stroke were identified. Thrombolysis rates increased continuously from 2.5% in 2003 to 8.4% in 2009. In patients admitted within 3 h after symptom onset, the thrombolysis rate was 2.5-fold higher in 2009 (25.4%) as compared to 2003 (10.5%). The mean age (±SD) of thrombolyzed patients increased from 68.7 (±11.5) years in 2003 to 70.7 (±13.4) years in 2009 (p for trend = 0.014), but remained stable in the entire cohort. 20.1% of all systemic thrombolytic treatments were performed in patients >80 years old. Disability at admission decreased more pronouncedly in rtPA-treated patients (Rankin Scale score 0-2: 15.2% in 2003 and 24.5% in 2009; p for trend <0.001) as compared to the entire cohort (34.5% in 2003 and 41.5% in 2009; p for trend <0.001). CONCLUSIONS: Thrombolytic therapy is increasingly used in acute stroke, particularly in patients admitted within the 3-hour time window. Higher treatment rates are at least partially explained by spreading rtPA application, including older and less severely affected patients. Approximately one fifth of all rtPA treatments were given to the very old (>80 years), which is outside the age limit for rtPA approval. In the light of upcoming demographic changes, the proportion of very aged stroke patients will increase substantially, further tightening the current discussion of an upper age limit for thrombolytic therapy.

Prior antiplatelet therapy and outcome following intracerebral hemorrhage: a systematic review.

OBJECTIVES: Antiplatelet therapy (APT) promotes bleeding; therefore, APT might worsen outcome in patients with intracerebral hemorrhage (ICH). We performed a systematic review and meta-analysis to address the hypothesis that pre-ICH APT use is associated with mortality and poor functional outcome following ICH. METHODS: The Medline and Embase databases were searched in February 2008 using relevant key words, limited to human studies in the English language. Cohort studies of consecutive patients with ICH reporting mortality or functional outcome according to pre-ICH APT use were identified. Of 2,873 studies screened, 10 were judged to meet inclusion criteria by consensus of 2 authors. Additionally, we solicited unpublished data from all authors of cohort studies with >100 patients published within the last 10 years, and received data from 15 more studies. Univariate and multivariable-adjusted odds ratios (ORs) for mortality and poor functional outcome were abstracted as available and pooled using a random effects model. RESULTS: We obtained mortality data from 25 cohorts (15 unpublished) and functional outcome data from 21 cohorts (14 unpublished). Pre-ICH APT users had increased mortality in both univariate (OR 1.41, 95% confidence interval [CI] 1.21 to 1.64) and multivariable-adjusted (OR 1.27, 95% CI 1.10 to 1.47) pooled analyses. By contrast, the pooled OR for poor functional outcome was no longer significant when using multivariable-adjusted estimates (univariate OR 1.29, 95% CI 1.09 to 1.53; multivariable-adjusted OR 1.10, 95% CI 0.93 to 1.29). CONCLUSIONS: In cohort studies, APT use at the time of ICH compared to no APT use was independently associated with increased mortality but not with poor functional outcome.

Invited article: searching for oracles? Blood biomarkers in acute stroke.

Emerging data suggest that a wide array of measurable biomarkers in blood may provide a novel window into the pathophysiology of stroke. In this review, we survey the state of progress in the field. Three specific questions are assessed. Can biomarkers augment the clinical examination and powerful brain imaging tools to enhance the accuracy of the diagnostic process? Can biomarkers be used to help triage patients for thrombolytic therapy? Can biomarkers help predict patients who are most susceptible to malignant infarction? Many encouraging molecular candidates have been found that appear to match the known cascades of neurovascular injury after stroke. However, whether these putative biomarkers may indeed have direct clinical utility remains to be quantitatively validated. Larger clinical trials are warranted to establish the sensitivity and specificity of biomarkers for routine use in clinical stroke.

Mechanisms and markers for hemorrhagic transformation after stroke.

Intracerebral hemorrhagic transformation is a multifactorial phenomenon in which ischemic brain tissue converts into a hemorrhagic lesion with blood vessel leakage. Hemorrhagic transformation can significantly contribute to additional brain injury after stroke. Especially threatening are the thrombolytic-induced hemorrhages after reperfusion therapy with tissue plasminogen activator (tPA), the only treatment available for ischemic stroke. In this context, it is important to understand its underlying mechanisms and identify early markers of hemorrhagic transformation, so that we can both search for new treatments as well as predict clinical outcomes in patients. In this review, we discuss the emerging mechanisms for hemorrhagic transformation after stroke, and briefly survey potential molecular, genetic, and neuroimaging markers that might be used for early detection of this challenging clinical problem.

Serum GFAP is a diagnostic marker for glioblastoma multiforme.

A serum marker for malignant cerebral astrocytomas could improve both differential diagnosis and clinical management of brain tumour patients. To evaluate whether the serum concentration of glial fibrillary acidic protein (GFAP) may indicate glioblastoma multiforme (GBM) in patients with single supratentorial space-occupying lesions, we prospectively examined 50 consecutive patients with histologically proven GBM, World Health Organization (WHO) grade IV, 14 patients with anaplastic astrocytoma (WHO grade III), 4 patients with anaplastic oligodendroglioma, 13 patients with diffuse astrocytoma (WHO grade II), 17 patients with a single cerebral metastasis and 50 healthy controls. Serum was taken from the patients before tumour resection or stereotactic biopsy. Serum GFAP levels were determined using a commercially available ELISA test and were detectable in 40 out of the 50 GBM patients (median: 0.18 microg/l; range: 0-5.6 microg/l). The levels were significantly elevated compared with those of the non-GBM tumour patients and healthy controls (median: 0 mug/l; range: 0-0.024 microg/l; P < 0.0001, respectively). Non-GBM tumour patients and all healthy subjects showed zero serum GFAP levels. There was a significant correlation between tumour volume (Spearman Rho, CC = 0.47; 95% confidence interval, 0.2-0.67; P < 0.001), tumour necrosis volume (CC = 0.49; 95% confidence interval, 0.2-0.72; P = 0.004), the amount of necrotic GFAP positive cells (CC = 0.61; 95% confidence interval, 0.29-0.81; P = 0.007) and serum GFAP level among the GBM patients. A serum GFAP level of >0.05 microg/l was 76% sensitive and 100% specific for the diagnosis of GBM in patients with a single supratentorial mass lesion in this series. Therefore, it can be concluded that serum GFAP constitutes a diagnostic biomarker for GBM. Future studies should investigate whether serum GFAP could also be used to monitor therapeutic effects and whether it may have a prognostic value.

Anthropometric approximation of body weight in unresponsive stroke patients.

BACKGROUND AND PURPOSE: Thrombolysis of acute ischaemic stroke is based strictly on body weight to ensure efficacy and to prevent bleeding complications. Many candidate stroke patients are unable to communicate their body weight, and there is often neither the means nor the time to weigh the patient. Instead, weight is estimated visually by the attending physician, but this is known to be inaccurate. METHODS: Based on a large general population sample of nearly 7000 subjects, we constructed approximation formulae for estimating body weight from simple anthropometric measurements (body height, and waist and hip circumference). These formulae were validated in a sample of 178 consecutive inpatients admitted to our stroke unit, and their accuracy was compared with the best visual estimation of two experienced physicians. RESULTS: The simplest formula gave the most accurate approximation (mean absolute difference 3.1 (2.6) kg), which was considerably better than the best visual estimation (physician 1: 6.5 (5.2) kg; physician 2: 7.4 (5.7) kg). It reduced the proportion of weight approximations mismatched by >10% from 31.5% and 40.4% (physicians 1 and 2, respectively) to 6.2% (anthropometric approximation). Only the patient's own estimation was more accurate (mean absolute difference 2.7 (2.4) kg). CONCLUSIONS: By using an approximation formula based on simple anthropometric measurements (body height, and waist and hip circumference), it is possible to obtain a quick and accurate approximation of body weight. In situations where the exact weight of unresponsive patients cannot be ascertained quickly, we recommend using this approximation method rather than visual estimation.

Serum glial fibrillary acidic protein as a biomarker for intracerebral haemorrhage in patients with acute stroke.

BACKGROUND: Biomarkers of stroke are an evolving field of clinical research. A serum marker which can differentiate between haemorrhagic and ischaemic stroke in the very early phase would help to optimise acute stroke management. OBJECTIVE: To examine whether serum glial fibrillary acidic protein (GFAP) identifies intracerebral haemorrhage (ICH) in acute stroke patients. METHODS: A pilot study assessing 135 stroke patients admitted within six hours after symptom onset. Diagnosis of ICH (n = 42) or ischaemic stroke (n = 93) was based on brain imaging. GFAP was determined from venous blood samples obtained immediately after admission, using a research immunoassay. RESULTS: GFAP was detectable in the serum of 39 patients (34 of 42 (81%) with ICH, and five of 93 (5%) with ischaemic stroke). Serum GFAP was substantially raised in patients with ICH (median 11 ng/l, range 0 to 3096 ng/l) compared with patients with ischaemic stroke (median 0 ng/l, range 0 to 14 ng/l, p<0.001). Using receiver operating characteristic curve analysis, a cut off point of 2.9 ng/l provided a sensitivity of 0.79 and a specificity of 0.98 for the identification of ICH in acute stroke (positive predictive value 0.94, negative predictive value 0.91; p<0.001). CONCLUSIONS: Serum GFAP can reliably detect ICH in the acute phase of stroke. Further evaluation of the usefulness of GFAP as an early diagnostic marker of ICH is now required, with the aim of optimising cause specific emergency management.

Survival and quality of life outcome after mechanical ventilation in elderly stroke patients.

OBJECTIVES: Mortality is high and functional outcome poor in mechanically ventilated stroke patients. In addition, age >65 years is an independent predictor of death at 2 months among these patients. Our objective was to determine survival rates, functional outcome, and quality of life (QoL) in stroke patients older than 65 years requiring mechanical ventilation. METHODS: A prospective cohort study with an additional cross-sectional survey in 65 patients aged 65 years and older (mean age (SD): 75.6 (6.0) years) with ischaemic or haemorrhagic stroke who underwent mechanical ventilation. Main outcome measures were survival rate at 6 months, and Barthel Index (BI), modified Rankin Scale, and QoL at 15.8 (SD 8.0) months. RESULTS: Survival rate at 6 months was 40%. Elective intubation (odds ratio (OR) 13.6; p = 0.002) was the only independent positive predictor for survival, while age >77.5 years (OR 0.1; p = 0.004) and white blood count >10/nl at admission (OR 0.31; p = 0.032) were independent negative predictors for survival at 6 months. At the time of the cross-sectional survey, BI was >70 in five out of 22 patients, 35-70 in three and <35 in the remaining 14 patients. QoL was impaired primarily in the physical domain, whereas the psychosocial domain was less affected. CONCLUSIONS: Although only 40% of elderly patients intubated in the acute phase of stroke survived at least 6 months, one in four survivors recovered to a good functional outcome with a reasonable QoL. Elderly stroke patients need to be selected carefully for intensive care treatment, but elective intubation to allow diagnostic procedures should not be withheld primarily based on their age.

S100B as a surrogate marker for successful clot lysis in hyperacute middle cerebral artery occlusion.

OBJECTIVES: The astroglial protein S100B is a marker of cerebral tissue damage. This study investigated whether the serum kinetic of S100B may serve as a surrogate marker of successful clot lysis and early recanalisation (<6 hours) in hyperacute proximal middle cerebral artery (MCA/M1) occlusion. METHODS: The authors prospectively included 23 patients (mean (SD) age, 70.2 (11.0) years) presenting with MCA/M1 occlusion on magnetic resonance angiography (n=18), intra-arterial angiography (IA; n=2), or transcranial Doppler sonography (TCD; n=3) within five hours after symptom onset. Rates of recanalisation and their point of time were determined using TCD or IA. Individual S100B values were determined at hospital admission, every eight hours within the first three days, and at 12 hour intervals from day 4 to day 6. Additionally, the S100B area under the curve (AUC) and the S100B peak value were obtained. RESULTS: Early recanalisation (<6 hours after symptom onset, n=7) was associated with a significantly lower mean S100B AUC compared with no recanalisation (22.2 (40.1) versus 406.8 (284.4) micro g/l per hour; p<0.001). Using receiver operating calculations, a single S100B value obtained 48-96 hours after stroke onset of less than 0.4 micro g/l (cut off point) provided a 86% sensitivity and 100% specificity for sufficient MCA/M1 clot lysis <6 hours. The overall accuracy for a single S100B value obtained in the 48-96 hours time window was as high as for the AUC (95.7%). CONCLUSION: A single S100B value <0.4 micro g/l obtained 48-96 hours after stroke onset indicates successful clot lysis <6 hours in MCA/M1 occlusion with a high degree of accuracy. Thus, determination of a single S100B value may serve as a surrogate marker of early and sufficient MCA/M1 recanalisation in large scale thrombolytic studies.

[Brain infarctions caused by paradoxical embolism during long-distance flights]. / Paradox-embolische Hirninfarkte bei Langstreckenflügen.

HISTORY AND ADMISSION FINDINGS: Over the period of one year three long-distance airline passengers (aged 21, 63, and 64 years) were admitted to our department because of a first-time acute neurological deficit having occurred during their long-distance flights. INVESTIGATIONS: In all three cases acute stroke MRI showed embolic cerebral ischemia, and transesophageal echocardiography revealed a persistent foramen ovale (PFO). Venous duplex and compression ultrasonography of the legs showed no signs of thrombosis. Extra- and transcranial Doppler, Holter ECG recording, routine blood analysis and additional tests for thrombophilia (incl. lupus anticoagulans, APC resistance, protein C, S, and AT III) revealed no signs of cardiovascular disease or other stroke causes. Only in case 3 the prothrombin gene G 20210A was found. DIAGNOSIS, TREATMENT AND COURSE: Ischemic stroke due to paradoxical embolism through a PFO was diagnosed in all three patients. One patient recovered fully within 2 days, one was discharged with a persistent motor deficit and the third patient died subsequently as a result of multiple cerebral infarctions accompanied by massive pulmonary embolism. CONCLUSION: These three cases illustrate that paradoxical embolic stroke is a possible severe complication of long-distance air travel in passengers with a PFO and this should be taken into account when deciding upon individual risk-adjusted prophylactic measures.