Inflammation triggers secondary brain damage after stroke. The meninges and other CNS border compartments serve as invasion sites for leukocyte influx into the brain thus promoting tissue damage ...after stroke. However, the post-ischemic immune response of border compartments compared to brain parenchyma remains poorly characterized. Here, we deeply characterize tissue-resident leukocytes in meninges and brain parenchyma and discover that leukocytes respond differently to stroke depending on their site of residence. We thereby discover a unique phenotype of myeloid cells exclusive to the brain after stroke. These stroke-associated myeloid cells partially resemble neurodegenerative disease-associated microglia. They are mainly of resident microglial origin, partially conserved in humans and exhibit a lipid-phagocytosing phenotype. Blocking markers specific for these cells partially ameliorates stroke outcome thus providing a potential therapeutic target. The injury-response of myeloid cells in the CNS is thus compartmentalized, adjusted to the type of injury and may represent a therapeutic target.
Primary angiitis of the central nervous system (PACNS) represents a rare inflammatory disease affecting the brain and spinal cord. Stroke, encephalopathy, headache and seizures are major clinical ...manifestations. The diagnosis of PACNS is based on the combination of clinical presentation, imaging findings (magnetic resonance imaging and angiography), brain biopsy, and laboratory and cerebral spinal fluid (CSF) values. PACNS can either be confirmed by magnetic resonance angiography (MRA)/conventional angiography or tissue biopsy showing the presence of typical histopathological patterns. Identification of PACNS mimics is often challenging in clinical practice, but crucial to avoid far-reaching treatment decisions. In view of the severity of the disease, with considerable morbidity and mortality, early recognition and treatment initiation is necessary. Due to the rareness and heterogeneity of the disease, there is a lack of randomized data on treatment strategies. Retrospective studies suggest the combined administration of cyclophosphamide and glucocorticoids as induction therapy. Immunosuppressants such as azathioprine, methotrexate or mycophenolate mofetil are often applied for maintenance therapy. In addition, the beneficial effects of two biological agents (anti-CD20 monoclonal antibody rituximab and tumour necrosis factor-α blocker) have been reported. Nevertheless, diagnosis and treatment is still a clinical challenge, and further insights into the immunopathogenesis of PACNS are required to improve the diagnosis and management of patients. The present review provides a comprehensive overview of diagnostics, differential diagnoses, and therapeutic approaches of adult PACNS.
Sodium chloride promotes vascular fibrosis, arterial hypertension, pro-inflammatory immune cell polarization and endothelial dysfunction, all of which might influence outcomes following stroke. But ...despite enormous translational relevance, the functional importance of sodium chloride in the pathophysiology of acute ischemic stroke is still unclear. In the current study, we show that high-salt diet leads to significantly worse functional outcomes, increased infarct volumes, and a loss of astrocytes and cortical neurons in acute ischemic stroke. While analyzing the underlying pathologic processes, we identified the migrasome as a novel, sodium chloride-driven pathomechanism in acute ischemic stroke. The migrasome was previously described in vitro as a migrating organelle, which incorporates and dispatches cytosol of surrounding cells and plays a role in intercellular signaling, whereas a pathophysiological meaning has not been elaborated. We here confirm previously reported characteristics of the migrasome in vivo. Immunohistochemistry, electron microscopy and proteomic analyses further demonstrate that the migrasome incorporates and dispatches cytosol of surrounding neurons following stroke. The clinical relevance of these findings is emphasized by neuropathological examinations, which detected migrasome formation in infarcted brain parenchyma of human stroke patients. In summary, we demonstrate that high-salt diet aggravates stroke outcomes, and we characterize the migrasome as a novel mechanism in acute stroke pathophysiology.
Purpose
Primary angiitis of the central nervous system (PACNS) is a heterogeneous, rare, and poorly understood inflammatory disease. We aimed at non-invasive imaging of activated ...microglia/macrophages in patients with PACNS by PET-MRI targeting the translocator protein (TSPO) with
18
FDPA-714 to potentially assist differential diagnosis, therapy monitoring, and biopsy planning.
Methods
In total, nine patients with ischemic stroke and diagnosed or suspected PACNS underwent
18
FDPA-714-PET-MRI. Dynamic PET scanning was performed for 60 min after injection of 233 ± 19 MBq
18
FDPA-714, and MRI was simultaneously acquired.
Results
In two PACNS patients,
18
FDPA-714 uptake patterns exceeded MRI correlates of infarction, whereas uptake was confined to the infarct in four patients where initial suspicion of PACNS could not be confirmed. About three patients with PACNS or cerebral predominant lymphocytic vasculitis showed no or only faintly increased uptake. Short-term
18
FDPA-714-PET follow-up in a patient with PACNS showed reduced lesional
18
FDPA-714 uptake after anti-inflammatory treatment. Biopsy in the same patient pinpointed the source of tracer uptake to TSPO-expressing immune cells.
Conclusions
18
FDPA-714-PET imaging may facilitate the diagnosis and treatment monitoring of PACNS. Further studies are needed to fully understand the potential of TSPO-PET in deciphering the heterogeneity of the disease.
Autoantibodies against contactin-associated protein 2 (CASPR2) are usually associated with autoimmune encephalitis and neuromyotonia. Their association with inflammatory neuropathies has been ...described in case reports albeit all with distal symmetric manifestation. Here, we report a patient who developed distal arm paresis, dominantly of the right arm, over the course of 1 year. Electroneurography showed a conduction block of motor nerve conduction, nerve ultrasonography a swelling of the right median and ulnar nerve and flow cytometry an increase in natural killer (NK cells) in the blood and natural killer T (NKT) cells in the cerebrospinal fluid (CSF), therefore indicating a multifocal motor neuropathy-like (MMN-like) phenotype. CASPR2 autoantibodies were detected in serum and CSF. Through immunotherapy with intravenous immunoglobulins the patient showed clinical and neurographic improvement. We therefore describe the first association of CASPR2 autoantibodies with a MMN-like clinical manifestation, extending the spectrum of CASPR2-associated diseases.
The "translational roadblock" between successful animal stroke studies and neutral clinical trials is usually attributed to conceptual weaknesses. However, we hypothesized that rodent studies cannot ...inform the human disease due to intrinsic pathophysiological differences between rodents and humans., i.e., differences in infarct evolution.
To verify our hypothesis, we employed a mixed study design and compared findings from meta-analyses of animal studies and a retrospective clinical cohort study. For animal data, we systematically searched pubmed to identify all rodent studies, in which stroke was induced by MCAO and at least two sequential MRI scans were performed for infarct volume assessment within the first two days. For clinical data, we included 107 consecutive stroke patients with large artery occlusion, who received MRI scans upon admission and one or two days later.
Our preclinical meta-analyses included 50 studies with 676 animals. Untreated animals had a median post-reperfusion infarct volume growth of 74%. Neuroprotective treatments reduced this infarct volume growth to 23%. A retrospective clinical cohort study showed that stroke patients had a median infarct volume growth of only 2% after successful recanalization. Stroke patients with unsuccessful recanalization, by contrast, experienced a meaningful median infarct growth of 148%.
Our study shows that rodents have a significant post-reperfusion infarct growth, and that this post-reperfusion infarct growth is the target of neuroprotective treatments. Stroke patients with successful recanalization do not have such infarct growth and thus have no target for neuroprotection.
Aims
To distinguish between the genuine cellular impact of the ischemic cascade by leukocytes and unspecific effects of edema and humoral components, two knock‐in mouse lines were utilized. Mouse ...lines Y731F and Y685F possess point mutations in VE‐cadherin, which lead to a selective inhibition of transendothelial leukocyte migration or impaired vascular permeability.
Methods
Ischemic stroke was induced by a model of middle cerebral artery occlusion. Analysis contained structural outcomes (infarct volume and extent of brain edema), functional outcomes (survival analysis, rotarod test, and neuroscore), and the extent and spatial distribution of leukocyte migration (heatmaps and fluorescence‐activated cell sorting (FACS) analysis).
Results
Inhibition of transendothelial leukocyte migration as in Y731F mice leads to smaller infarct volumes (52.33 ± 4719 vs. 70.43 ± 6483 mm3, p = .0252) and improved motor skills (rotarod test: 85.52 ± 13.24 s vs. 43.06 ± 15.32 s, p = .0285). An impaired vascular permeability as in Y685F mice showed no effect on structural or functional outcomes. Both VE‐cadherin mutations did not influence the total immune cell count or spatial distribution in ischemic brain parenchyma.
Conclusion
Selective inhibition of transendothelial leukocyte migration by VE‐cadherin mutation after ischemic stroke in a mouse model leads to smaller infarct volumes and improved motor skills.
Inhibition of leukocyte migration after ischemic stroke by VE‐cadherin mutation in a mouse model leads to reduced infarct volumes and improved motor skills. VE‐cadherin mutation Y731F is associated with a selective inhibition of transendothelial leukocyte migration. In a mouse model of ischemic stroke, it led to smaller infarct volumes and improved motor skills. VE‐cadherin mutation Y685F had no effect on structural or functional outcomes on the same mouse model of ischemic stroke.
Besides being affected by the rare and severe primary angiitis of the central nervous system (PACNS) the nervous system is also affected by primary systemic vasculitides (PSV). In contrast to PACNS, ...PSV affect not only the central but also the peripheral nervous system, resulting in a large array of potential symptoms. Given the high burden of disease, difficulties in distinguishing between differential diagnoses, and incomplete pathophysiological insights, there is an urgent need for additional precise diagnostic tools to enable an earlier diagnosis and initiation of effective treatments. Methods available to date, such as inflammatory markers, antibodies, cerebrospinal fluid (CSF) analysis, imaging, and biopsy, turn out to be insufficient to meet all current challenges. We highlight the use of biomarkers as an approach to extend current knowledge and, ultimately, improve patient management. Biomarkers are considered to be useful for disease diagnosis and monitoring, for predicting response to treatment, and for prognosis in clinical practice, as well as for establishing outcome parameters in clinical trials. In this article, we review the recent literature on biomarkers which have been applied in the context of different types of nervous system vasculitides including PACNS, giant-cell arteritis, Takayasu's arteritis, polyarteritis nodosa, ANCA (anti-neutrophil cytoplasm antibody)-associated vasculitides, cryoglobulinemic vasculitis, IgA vasculitis, and Behçet's disease. Overall, the majority of biomarkers is not specific for vasculitides of the nervous system.
Automated perfusion imaging can detect stroke patients with unknown time of symptom onset who are eligible for thrombolysis. However, the availability of this technique is limited. We, therefore, ...established the novel concept of computed tomography (CT) hypoperfusion-hypodensity mismatch, i.e., an ischemic core lesion visible on cerebral perfusion CT without visible hypodensity in the corresponding native cerebral CT. We compared both methods regarding their accuracy in identifying patients suitable for thrombolysis.
In a retrospective analysis of the MissPerfeCT observational cohort study, patients were classified as suitable or not for thrombolysis based on established time window and imaging criteria. We calculated predictive values for hypoperfusion-hypodensity mismatch and automated perfusion imaging to compare accuracy in the identification of patients suitable for thrombolysis.
Of 247 patients, 219 (88.7%) were eligible for thrombolysis and 28 (11.3%) were not eligible for thrombolysis. Of 197 patients who were within 4.5 h of symptom onset, 190 (96.4%) were identified by hypoperfusion-hypodensity mismatch and 88 (44.7%) by automated perfusion mismatch (
< 0.001). Of 22 patients who were beyond 4.5 h of symptom onset but were eligible for thrombolysis, 5 patients (22.7%) were identified by hypoperfusion-hypodensity mismatch. Predictive values for the hypoperfusion-hypodensity mismatch vs. automated perfusion mismatch were as follows: sensitivity, 89.0% vs. 50.2%; specificity, 71.4% vs. 100.0%; positive predictive value, 96.1% vs. 100.0%; and negative predictive value, 45.5% vs. 20.4%.
The novel method of hypoperfusion-hypodensity mismatch can identify patients suitable for thrombolysis with higher sensitivity and lower specificity than established techniques. Using this simple method might therefore increase the proportion of patients treated with thrombolysis without the use of special automated software.The MissPerfeCT study is a retrospective observational multicenter cohort study and is registered with clinicaltrials.gov (NCT04277728).
Background:
Up to every fourth woman with multiple sclerosis (MS) or neuromyelitis optica spectrum disorder (NMOSD) suffers a clinically relevant relapse during pregnancy. High doses of steroids bear ...some serious risks, especially within the first trimester of pregnancy. Immunoadsorption (IA) is an effective and more selective treatment option in disabling MS relapse than plasma exchange. Data on the use of IA during pregnancy and breastfeeding are scarce.
Methods:
In this retrospective multicenter study, we analyzed the safety and efficacy of IA treatment in acute relapses during pregnancy or breastfeeding. The primary outcome parameter - change of acute relapse-related disability after IA - was assessed using Expanded Disability Status Scale (EDSS) and visual acuity (VA) measurements for patients with optic neuritis (ON).
Results:
A total of 24 patients were analyzed, 23 with relapsing–remitting MS, and 1 with NMOSD. Twenty patients were treated with IA during pregnancy. Four patients received IA postnatally during the breastfeeding period. Treatment was started at a mean 22.5 standard deviation (SD) 13.9 days after onset of relapse. Patients were treated with a series of 5.8 (mean, SD 0.7) IA treatments within 7–10 days. Sixteen patients received IA because of steroid-refractory relapse, eight were treated without preceding steroid pulse therapy. EDSS improved clinically relevant from 3.5 median, interquartile range (IQR) 2 before IA to 2.5 (median, IQR 1.1) after IA, p < 0.001. In patients with ON, VA improved in four out of five patients. Altogether, in 83% of patients, a rapid and marked improvement of relapse-related symptoms was observed after IA with either a decrease of ⩾1 EDSS grade or improvement in VA ⩾20%. No clinically relevant side effect was reported in 138 IA treatments.
Conclusions:
Tryptophan-IA was found to be effective and well tolerated in MS/NMOSD relapses, both as an escalation option after insufficient response to steroid pulse therapy and as first-line relapse treatment during pregnancy and breastfeeding.
PDF
