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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: Standardized neuropsychological testing serves to quantify cognitive impairment in multiple sclerosis (MS) patients. However, the exact mechanism underlying the translation of cognitive dysfunction into difficulties in everyday tasks has remained unclear. To answer this question, we tested if MS patients with intact vs. impaired information processing speed measured by the Symbol Digit Modalities Test (SDMT) differ in their visual search behavior during ecologically valid tasks reflecting everyday activities.
Methods: Forty-three patients with relapsing-remitting MS enrolled in an eye-tracking experiment consisting of a visual search task with naturalistic images. Patients were grouped into “impaired” and “unimpaired” according to their SDMT performance. Reaction time, accuracy and eye-tracking parameters were measured.
Results: The groups did not differ regarding age, gender, and visual acuity. Patients with impaired SDMT (cut-off SDMT-z-score < −1.5) performance needed more time to find and fixate the target (q = 0.006). They spent less time fixating the target (q = 0.042). Impaired patients had slower reaction times and were less accurate (both q = 0.0495) even after controlling for patients' upper extremity function. Exploratory analysis revealed that unimpaired patients had higher accuracy than impaired patients particularly when the announced target was in unexpected location (p = 0.037). Correlational analysis suggested that SDMT performance is inversely linked to the time to first fixation of the target only if the announced target was in its expected location (r = −0.498, p = 0.003 vs. r = −0.212, p = 0.229).
Conclusion: Dysfunctional visual search behavior may be one of the mechanisms translating cognitive deficits into difficulties in everyday tasks in MS patients. Our results suggest that cognitively impaired patients search their visual environment less efficiently and this is particularly evident when top-down processes have to be employed.
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.
The acute superficial siderosis syndrome — clinical entity, imaging findings, and histopathology
(2022)
Superficial siderosis is a consequence of repetitive bleeding into the subarachnoid space, leading to toxic iron and hemosiderin deposits on the surface of the brain and spine. The clinical and radiological phenotypes of superficial siderosis are known to manifest over long time intervals. In contrast, this study defines the “acute superficial siderosis syndrome” and illustrates typical imaging and histopathological findings of this entity. We describe the case of a 61-year-old male patient who was diagnosed with a melanoma metastasis in the right frontal cortex in February 2019. Within a few weeks he developed a progressive syndrome characterized by cerebellar ataxia, gait disturbance, signs of myelopathy, and radiculopathy. MRI revealed ongoing hemorrhage from the metastasis into the lateral ventricle and the subarachnoid space. A semiquantitative assessment of three subsequent MRI within an 8-week period documented the rapid development of superficial siderosis along the surface of the cerebellum, the brain stem, and the lower parts of the supratentorial regions on T2*-weighted sequences. The diagnosis of a superficial siderosis was histopathologically confirmed by identifying iron and hemosiderin deposits on the cortex along with astrogliosis. The recognition of this “acute superficial siderosis syndrome” triggered surgical removal of the hemorrhagic metastasis. Based on a single case presentation, we define the “acute superficial siderosis syndrome” as a clinical entity and describe the radiological and histopathological characteristics of this entity. Early recognition of this syndrome may allow timely elimination of the bleeding source, in order to prevent further clinical deterioration.
Background and purpose: Superficial siderosis of the central nervous system is a sporadic finding in magnetic resonance imaging, resulting from recurrent bleedings into the subarachnoid space. This study aimed to determine the frequency of spinal dural cerebrospinal fluid (CSF) leaks amongst patients with a symmetric infratentorial siderosis pattern. Methods: In all, 97,733 magnetic resonance images performed between 2007 and 2018 in our neurocenter were screened by a keyword search for “hemosiderosis” and “superficial siderosis.” Siderosis patterns on brain imaging were classified according to a previously published algorithm. Potential causative intracranial bleeding events were also assessed. Patients with a symmetric infratentorial siderosis pattern but without causative intracranial bleeding events in history were prospectively evaluated for spinal pathologies. Results: Forty-two patients with isolated supratentorial siderosis, 30 with symmetric infratentorial siderosis and 21 with limited (non-symmetric) infratentorial siderosis were identified. Amyloid angiopathy and subarachnoid hemorrhage were causes for isolated supratentorial siderosis. In all four patients with a symmetric infratentorial siderosis pattern but without a causative intracranial bleeding event in history, spinal dural abnormalities were detected. Dural leaks were searched for in patients with symmetric infratentorial siderosis and a history of intracranial bleeding event without known bleeding etiology, considering that spinal dural CSF leaks themselves may also cause intracranial hemorrhage, for example by inducing venous thrombosis due to low CSF pressure. Thereby, one additional spinal dural leak was detected. Conclusions: Persisting spinal dural CSF leaks can frequently be identified in patients with a symmetric infratentorial siderosis pattern. Diagnostic workup in these cases should include magnetic resonance imaging of the whole spine.
Background and purpose: Superficial siderosis of the central nervous system is a sporadic finding in magnetic resonance imaging, resulting from recurrent bleedings into the subarachnoid space. This study aimed to determine the frequency of spinal dural cerebrospinal fluid (CSF) leaks amongst patients with a symmetric infratentorial siderosis pattern. Methods: In all, 97,733 magnetic resonance images performed between 2007 and 2018 in our neurocenter were screened by a keyword search for “hemosiderosis” and “superficial siderosis.” Siderosis patterns on brain imaging were classified according to a previously published algorithm. Potential causative intracranial bleeding events were also assessed. Patients with a symmetric infratentorial siderosis pattern but without causative intracranial bleeding events in history were prospectively evaluated for spinal pathologies. Results: Forty-two patients with isolated supratentorial siderosis, 30 with symmetric infratentorial siderosis and 21 with limited (non-symmetric) infratentorial siderosis were identified. Amyloid angiopathy and subarachnoid hemorrhage were causes for isolated supratentorial siderosis. In all four patients with a symmetric infratentorial siderosis pattern but without a causative intracranial bleeding event in history, spinal dural abnormalities were detected. Dural leaks were searched for in patients with symmetric infratentorial siderosis and a history of intracranial bleeding event without known bleeding etiology, considering that spinal dural CSF leaks themselves may also cause intracranial hemorrhage, for example by inducing venous thrombosis due to low CSF pressure. Thereby, one additional spinal dural leak was detected. Conclusions: Persisting spinal dural CSF leaks can frequently be identified in patients with a symmetric infratentorial siderosis pattern. Diagnostic workup in these cases should include magnetic resonance imaging of the whole spine.
Background: Fingolimod is used for immune therapy in patients with multiple sclerosis. Long-term treatment is associated with a small increase in the risk of herpes virus reactivation and respiratory tract infections. Patients with coronavirus disease 2019 (COVID-19) under Fingolimod treatment have not been described.
Methods and results. We report a 57-year old female patient with a relapsing remitting multiple sclerosis under fingolimod treatment who experienced a severe COVID-19 infection in March 2020 (Extended Disability Status Scale: 2.0). Having peripheral lymphopenia typical for fingolimod treatment (total lymphocytes 0.39/nL [reference range 1.22-3.56]), the patient developed bilateral interstitial pneumonia with multiple ground-glass opacities on chest CT. Fingolimod medication was stopped. On the intensive care unit, non-invasive ventilation was used to provide oxygen and ventilation support regularly. Over the following two days, oxygenation improved, and the patient was transferred to a normal ward five days after admission.
Conclusion: The implications fingolimod has on COVID-19 are complex. As an S1P analogue, fingolimod might enhance lung endothelial cell integrity. In addition, in case of a so-called cytokine storm, immunomodulation might be beneficial to reduce mortality. Future studies are needed to explore the risks and therapeutic effects of fingolimod in COVID-19 patients.
Serum GFAP for stroke diagnosis in regions with limited access to brain imaging (BE FAST India)
(2021)
Introduction: Despite a high burden of stroke, access to rapid brain imaging is limited in many middle- and low-income countries. Previous studies have described the astroglial protein GFAP (glial fibrillary acidic protein) as a biomarker of intracerebral hemorrhage. The aim of this study was to test the diagnostic accuracy of GFAP for ruling out intracranial hemorrhage in a prospective cohort of Indian stroke patients. Patients and methods: This study was conducted in an Indian tertiary hospital (Christian Medical College, Ludhiana). Patients with symptoms suggestive of acute stroke admitted within 12 h of symptom onset were enrolled. Blood samples were collected at hospital admission. Single Molecule Array technology was used for determining serum GFAP concentrations. Results: A total number of 155 patients were included (70 intracranial hemorrhage, 75 ischemic stroke, 10 stroke mimics). GFAP serum concentrations were elevated in intracranial hemorrhage patients compared to ischemic stroke patients [median (interquartile range) 2.36 µg/L (0.61–7.16) vs. 0.18 µg/L (0.11–0.38), p < 0.001]. Stroke mimics patients had a median GFAP serum level of 0.14 µg/L (0.09–0.26). GFAP values below the cut-off of 0.33 µg/L (area under the curve 0.871) ruled out intracranial hemorrhage with a negative predictive value of 89.7%, (at a sensitivity for detecting intracranial hemorrhage of 90.0%). Discussion: The high negative predictive value of a GFAP test system allows ruling out patients with intracranial hemorrhage. Conclusion: In settings where immediate brain imaging is not available, this would enable to implement secondary prevention (e.g., aspirin) in suspected ischemic stroke patients as soon as possible.
Propranolol as a potentially novel treatment of arteriovenous malformations: from bench to bedside
(2022)
Background: Propranolol is a non-selective blocker of the β-adrenergic receptor and has been used for treatment of proliferative infantile hemangiomas. The vasoconstrictive and antiangiogenic effects of propranolol led us to explore its potential application for the treatment of AVMs.
Methods: AVM tissue was cultured after surgical resection in the presence of 100μM propranolol or solvent DMSO. After incubation for 72 hours, tissue was harvested for testing. The expression levels of SDF1α, CXCR4, VEGF and HIF-1 was measured by rt-PCR. Furthermore, data of patients in 2 vascular centres harboring AVM was retrospectively interrogated for a time period of 20 years. The database included information about hemorrhage, AVM size and antihypertensive medication. Descriptive analyses were performed, focusing on the risk of hemorrhage, size of the lesion at presentation and clinical follow-up in patients on β-blocker medication versus those who were not.
Results: Among 483 patients, 73 (15%) were under β-blocker-treatment. 48% AVMs presented with hemorrhage at diagnosis. Patients under β-blocker-treatment had a lower risk of hemorrhage at the time of diagnosis in a univariate analysis (p<0,0001;OR13). Patients under β-blocker-treatment showed a significant higher chance for a lower Spetzler-Martin-grade ≤III (p<0,0001;OR6,5) and a lower risk for the presence of an associated aneurysm (p<0,0001;OR3,6).
Multivariate analysis including Spetzler-Martin-Grading, young age ≤50, presence of associated aneurysm and β-blocker-treatment showed reduced risk for hemorrhage under β-blocker-treatment (p<0,01,OR0,2).
The expression of CXCR4 was suppressed by propranolol most likely through the HIF-1-pathways. The gene-expression of vasculogenesis factors was decreased in with propranolol incubated AVMs.
Conclusion: β-Blocker medication seems to be associated with a decreased risk of AVM-related hemorrhage and AVM-size at presentation or during follow-up. Propranolol inhibits SDF1α-induced vasculogenesis by suppressing the expression of CXCR4 most likely through the HIF-1-pathways. Therefore, SDF1α/CXCR4 axis plays an important role in the vasculogenesis and migration of inflammatory cells in AVM lesions.