Refine
Year of publication
Document Type
- Article (30)
Language
- English (30)
Has Fulltext
- yes (30)
Is part of the Bibliography
- no (30)
Keywords
- stroke (9)
- CRM (3)
- Stroke (3)
- ceramides (3)
- sphingosine 1-phosphate (3)
- FTY720 (2)
- Hemorrhage (2)
- S1P receptors (2)
- Thrombolysis (2)
- emergency care (2)
Institute
- Medizin (30)
- MPI für Hirnforschung (1)
- Pharmazie (1)
Objective: Area postrema (AP) syndrome (defined as: nausea and/or emesis and/or singultus at onset of brainstem dysfunction) comprises complex pathophysiologic mechanisms triggered by different entities. The first objective was to assess the frequency of AP syndrome as a clinical feature in brainstem encephalitis (BE). Finding an especially high prevalence of AP syndrome in Bickerstaff brainstem encephalitis (BBE), we also analyzed the frequency of AP syndrome in other autoimmune diseases with anti‐ganglioside antibodies (Guillain–Barré syndrome (GBS) and its variants).
Methods: We systematically evaluated the prevalence of AP syndrome in BE in all patients treated at our university hospital during a 15‐year period. In a second step, BBE patients were compared to GBS and Miller Fisher syndrome (MFS) patients as clinical subtypes of a disease continuum without brainstem dysfunction.
Results: We found AP syndrome in 8 of 21 BE patients, including 3 of 7 BBE and in 4 of 112 GBS/MFS patients. AP syndrome was as a frequent but under‐recognized feature of BE with a significant impact on patients’ well being.
Interpretation: Manifestation of AP syndrome in BBE but also in GBS and its subtypes point toward a role of autoimmune antibodies that should be investigated in future studies. Considerable misdiagnosis or nonrecognition complicates diagnostic and therapeutic management. Therefore, AP syndrome should be considered in any episode of otherwise unexplained nausea, emesis, or singultus.
Sphingosine 1-phosphate (S1P) signaling influences numerous cell biological mechanisms such as differentiation, proliferation, survival, migration, and angiogenesis. Intriguingly, our current knowledge is based solely on the role of S1P with an 18-carbon long-chain base length, S1P d18:1. Depending on the composition of the first and rate-limiting enzyme of the sphingolipid de novo metabolism, the serine palmitoyltransferase, other chain lengths have been described in vivo. While cells are also able to produce S1P d20:1, its abundance and function remains elusive so far. Our experiments are highlighting the role of S1P d20:1 in the mouse central nervous system (CNS) and human glioblastoma. We show here that S1P d20:1 and its precursors are detectable in both healthy mouse CNS-tissue and human glioblastoma. On the functional level, we focused our work on one particular, well-characterized pathway, the induction of cyclooxygenase (COX)-2 expression via the S1P receptor 2 (S1P2). Intriguingly, S1P d20:1 only fairly induces COX-2 expression and can block the S1P d18:1-induced COX-2 expression mediated via S1P2 activation in the human glioblastoma cell line LN229. This data indicates that S1P d20:1 might act as an endogenous modulator of S1P signaling via a partial agonism at the S1P2 receptor. While our findings might stimulate further research on the relevance of long-chain base lengths in sphingolipid signaling, the metabolism of S1P d20:1 has to be considered as an integral part of S1P signaling pathways in vivo.
Background and purpose: Impaired kidney function is associated with an increased risk of vascular events in acute stroke patients, when assessed by single measurements of estimated glomerular filtration rate (eGFR). It is unknown whether repeated measurements provide additional information for risk prediction.
Methods: The MonDAFIS (Systematic Monitoring for Detection of Atrial Fibrillation in Patients with Acute Ischemic Stroke) study randomly assigned 3465 acute ischemic stroke patients to either standard procedures or an additive Holter electrocardiogram. Baseline eGFR (CKD-EPI formula) were dichotomized into values of < versus ≥60 ml/min/1.73 m2. eGFR dynamics were classified based on two in-hospital values as “stable normal” (≥60 ml/min/1.73 m2), “increasing” (by at least 15% from baseline, second value ≥ 60 ml/min/1.73 m2), “decreasing” (by at least 15% from baseline of ≥60 ml/min/1.73 m2), and “stable decreased” (<60 ml/min/1.73 m2). The composite endpoint (stroke, major bleeding, myocardial infarction, all-cause death) was assessed after 24 months. We estimated hazard ratios in confounder-adjusted models.
Results: Estimated glomerular filtration rate at baseline was available in 2947 and a second value in 1623 patients. After adjusting for age, stroke severity, cardiovascular risk factors, and randomization, eGFR < 60 ml/min/1.73 m2 at baseline (hazard ratio [HR] = 2.2, 95% confidence interval [CI] = 1.40–3.54) as well as decreasing (HR = 1.79, 95% CI = 1.07–2.99) and stable decreased eGFR (HR = 1.64, 95% CI = 1.20–2.24) were independently associated with the composite endpoint. In addition, eGFR < 60 ml/min/1.732 at baseline (HR = 3.02, 95% CI = 1.51–6.10) and decreasing eGFR were associated with all-cause death (HR = 3.12, 95% CI = 1.63–5.98).
Conclusions: In addition to patients with low eGFR levels at baseline, also those with decreasing eGFR have increased risk for vascular events and death; hence, repeated estimates of eGFR might add relevant information to risk prediction.
Background: To meet the requirements imposed by the time-dependency of acute stroke therapies, it is necessary 1) to initiate structural and cultural changes in the breadth of stroke-ready hospitals and 2) to find new ways to train the personnel treating patients with acute stroke. We aimed to implement and validate a composite intervention of a stroke team algorithm and simulation-based stroke team training as an effective quality initiative in our regional interdisciplinary neurovascular network consisting of 7 stroke units.
Methods: We recorded door-to-needle times of all consecutive stroke patients receiving thrombolysis at seven stroke units for 3 months before and after a 2 month intervention which included setting up a team-based stroke workflow at each stroke unit, a train-the-trainer seminar for stroke team simulation training and a stroke team simulation training session at each hospital as well as a recommendation to take up regular stroke team trainings.
Results: The intervention reduced the network-wide median door-to-needle time by 12 minutes from 43,0 (IQR 29,8–60,0, n = 122) to 31,0 (IQR 24,0–42,0, n = 112) minutes (p < 0.001) and substantially increased the share of patients receiving thrombolysis within 30 minutes of hospital arrival from 41.5% to 59.6% (p < 0.001). Stroke team training participants stated a significant increase in knowledge on the topic of acute stroke care and in the perception of patient safety. The overall course concept was regarded as highly useful by most participants from different professional backgrounds.
Conclusions: The composite intervention of a binding team-based algorithm and stroke team simulation training showed to be well-transferable in our regional stroke network. We provide suggestions and materials for similar campaigns in other stroke networks.
Purpose: Quantitative T2'-mapping detects regional changes of the relation of oxygenated and deoxygenated hemoglobin (Hb) by using their different magnetic properties in gradient echo imaging and might therefore be a surrogate marker of increased oxygen extraction fraction (OEF) in cerebral hypoperfusion. Since elevations of cerebral blood volume (CBV) with consecutive accumulation of Hb might also increase the fraction of deoxygenated Hb and, through this, decrease the T2’-values in these patients we evaluated the relationship between T2’-values and CBV in patients with unilateral high-grade large-artery stenosis.
Materials and Methods Data from 16 patients (13 male, 3 female; mean age 53 years) with unilateral symptomatic or asymptomatic high-grade internal carotid artery (ICA) or middle cerebral artery (MCA) stenosis/occlusion were analyzed. MRI included perfusion-weighted imaging and high-resolution T2’-mapping. Representative relative (r)CBV-values were analyzed in areas of decreased T2’ with different degrees of perfusion delay and compared to corresponding contralateral areas.
Results: No significant elevations in cerebral rCBV were detected within areas with significantly decreased T2’-values. In contrast, rCBV was significantly decreased (p<0.05) in regions with severe perfusion delay and decreased T2’. Furthermore, no significant correlation between T2’- and rCBV-values was found. Conclusions rCBV is not significantly increased in areas of decreased T2’ and in areas of restricted perfusion in patients with unilateral high-grade stenosis. Therefore, T2’ should only be influenced by changes of oxygen metabolism, regarding our patient collective especially by an increase of the OEF. T2’-mapping is suitable to detect altered oxygen consumption in chronic cerebrovascular disease.
Purpose: To investigate cortical thickness and cortical quantitative T2 values as imaging markers of microstructural tissue damage in patients with unilateral high-grade internal carotid artery occlusive disease (ICAOD).
Methods: A total of 22 patients with ≥70% stenosis (mean age 64.8 years) and 20 older healthy control subjects (mean age 70.8 years) underwent structural magnetic resonance imaging (MRI) and high-resolution quantitative (q)T2 mapping. Generalized linear mixed models (GLMM) controlling for age and white matter lesion volume were employed to investigate the effect of ICAOD on imaging parameters of cortical microstructural integrity in multivariate analyses.
Results: There was a significant main effect (p < 0.05) of the group (patients/controls) on both cortical thickness and cortical qT2 values with cortical thinning and increased cortical qT2 in patients compared to controls, irrespective of the hemisphere. The presence of upstream carotid stenosis had a significant main effect on cortical qT2 values (p = 0.01) leading to increased qT2 in the poststenotic hemisphere, which was not found for cortical thickness. The GLMM showed that in general cortical thickness was decreased and cortical qT2 values were increased with increasing age (p < 0.05).
Conclusion: Unilateral high-grade carotid occlusive disease is associated with widespread cortical thinning and prolongation of cortical qT2, presumably reflecting hypoperfusion-related microstructural cortical damage similar to accelerated aging of the cerebral cortex. Cortical thinning and increase of cortical qT2 seem to reflect different aspects and different pathophysiological states of cortical degeneration. Quantitative T2 mapping might be a sensitive imaging biomarker for early cortical microstructural damage.
Objectives: Until now, thrombectomy studies have provided little reliable information about the correlation between the infarct topography and clinical outcome of acute stroke patients with embolic large-vessel occlusions. Therefore, we aimed to analyze whether infarcts of the corticospinal tracts in the central white matter (CWM) or the internal capsule on postinterventional imaging controls are associated with poor clinical outcome after thrombectomy. Materials and Methods: We retrospectively analyzed imaging data from 70 patients who underwent endovascular thrombectomy for emergent middle cerebral artery or carotid-T occlusions. Inclusion criteria were postinterventional infarct demarcation in the regions of the internal capsule, caudate, lentiform nucleus, and CWM. Primary outcome was the mRS after 90 days and secondary endpoints were subgroup analyses regarding additional cortical infarction. Conclusions: In this exploratory study, we found no indication that infarcts in the course of the corticospinal tracts predict poor clinical outcome after successful thrombectomy in patients with embolic carotid-T or M1 occlusions. In our analysis, a significant number of patients showed a favorable 90 day outcome. Additional cortical infarcts may have a greater impact on the risk of an unfavorable outcome. Results: Good clinical outcome after 90 days (mRS 0–2) was shown in 36 out of 70 patients (51.4%), with excellent clinical outcome (mRS 0–1) in 23 patients (32.9%). Here, 58.6% patients lived at home without nursing service after 90 days. Patients with minimal additional cortical infarction in postinterventional imaging had a 75.6% better chance of excellent outcome.
Background: Oral anticoagulant therapy (OAT) with warfarin is the standard of stroke prevention in patients with atrial fibrillation. Approximately 30% of patients with cardioembolic strokes are on OAT at the time of symptom onset. We investigated whether warfarin exacerbates the risk of thrombolysis-associated hemorrhagic transformation (HT) in a mouse model of ischemic stroke.
Methods: 62 C57BL/6 mice were used for this study. To achieve effective anticoagulation, warfarin was administered orally. We performed right middle cerebral artery occlusion (MCAO) for 3 h and assessed functional deficit and HT blood volume after 24 h.
Results: In non-anticoagulated mice, treatment with rt-PA (10 mg/kg i.v.) after 3 h MCAO led to a 5-fold higher degree of HT compared to vehicle-treated controls (4.0±0.5 µl vs. 0.8±0.1, p<0.001). Mice on warfarin revealed larger amounts of HT after rt-PA treatment in comparison to non-anticoagulated mice (9.2±3.2 µl vs. 2.8±1.0, p<0.05). The rapid reversal of anticoagulation by means of prothrombin complex concentrates (PCC, 100 IU/kg) at the end of the 3 h MCAO period, but prior to rt-PA administration, neutralized the exacerbated risk of HT as compared to sham-treated controls (3.8±0.7 µl vs. 15.0±3.8, p<0.001).
Conclusion: In view of the vastly increased risk of HT, it seems to be justified to withhold tPA therapy in effectively anticoagulated patients with acute ischemic stroke. The rapid reversal of anticoagulation with PCC prior to tPA application reduces the risk attributed to warfarin pretreatment and may constitute an interesting therapeutic option.
Background: FTY720, an immunomodulator derived from a fungal metabolite which reduces circulating lymphocyte counts by increasing the homing of lymphocytes to the lymph nodes has recently gained interest in stroke research. The aim of this study was to evaluate the protective efficacy of FTY720 in cerebral ischemia in two different application paradigms and to gather first data on the effect of FTY720 on the rate of spontaneous bacterial infections in experimental stroke. Methods: Middle cerebral artery occlusion (MCAO) in C57BL/6 mice (strain J, groups of 10 animals) was performed with two different durations of ischemia (90 min and 3 h) and FTY720 was applied 2 h after vessel occlusion to study the impact of reperfusion on the protective potency of FTY720. Lesion size was determined by TTC staining. Mice treated with FTY720 or vehicle were sacrificed 48 h after 90 min MCAO to determine the bacterial burden in lung and blood. Results: FTY720 1 mg/kg significantly reduced ischemic lesion size when administered 2 h after the onset of MCAO for 3 h (45.4 +/- 22.7 mm3 vs. 84.7 +/- 23.6 mm3 in control mice, p = 0.001) and also when administered after reperfusion, 2 h after the onset of MCAO for 90 min (31.1 +/- 28.49 mm3 vs. 69.6 +/- 27.2 mm3 in control mice, p = 0.013). Bacterial burden of lung homogenates 48 h after stroke did not increase in the group treated with the immunomodulator FTY720 while there was no spontaneous bacteremia 48 h after MCAO in treated and untreated animals. Conclusions: Our results corroborate the experimental evidence of the protective effect of FTY720 seen in different rodent stroke models. Interestingly, we found no increase in bacterial lung infections even though FTY720 strongly reduces the number of circulating leukocytes.
We present the case of an aphasic 77-year-old stroke patient with left distal M1 occlusion who received rt-PA for thrombolysis while on oral anticoagulant treatment with dabigatran (150 mg b.i.d.). Coagulation parameters were normal (thrombin time 20 s, aPTT 20 s, INR 1.08) and the patient improved from an NIHSS of 15 to 5 within 24 h with sonographic evidence of M1 recanalization. She did not develop intracranial bleeding complications but showed unusually large diffuse skin ecchymoses. In our report, we give an overview of all reported cases of thrombolysis under dabigatran anticoagulation and discuss the questions of medication adherence under novel oral anticoagulants (NOA) and the safety of NOA in terms of secondary intracerebral hemorrhage after stroke.