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Introduction
We investigated a slow-cortical potential (SCP) neurofeedback therapy approach for rehabilitating chronic attention deficits after stroke. This study is the first attempt to train patients who survived stroke with SCP neurofeedback therapy.
Methods
We included N = 5 participants in a within-subjects follow-up design. We assessed neuropsychological and psychological performance at baseline (4 weeks before study onset), before study onset, after neurofeedback training, and at 3 months follow-up. Participants underwent 20 sessions of SCP neurofeedback training.
Results
Participants learned to regulate SCPs toward negativity, and we found indications for improved attention after the SCP neurofeedback therapy in some participants. Quality of life improved throughout the study according to engagement in activities of daily living. The self-reported motivation was related to mean SCP activation in two participants.
Discussion
We would like to bring attention to the potential of SCP neurofeedback therapy as a new rehabilitation method for treating post-stroke cognitive deficits. Studies with larger samples are warranted to corroborate the results.
Besides their central role in haemostasis and thrombosis, platelets are increasingly recognised as versatile effector cells in inflammation, the innate and adaptive immune response, extracellular matrix reorganisation and fibrosis, maintenance of barrier and organ integrity, and host response to pathogens. These platelet functions, referred to as thrombo-inflammation and immunothrombosis, have gained major attention in the COVID-19 pandemic, where patients develop an inflammatory disease state with severe and life-threatening thromboembolic complications. In the CRC/TR 240, a highly interdisciplinary team of basic, translational and clinical scientists explored these emerging roles of platelets with the aim to develop novel treatment concepts for cardiovascular disorders and beyond. We have i) unravelled mechanisms leading to life-threatening thromboembolic complica-tions following vaccination against SARS-CoV-2 with adenoviral vector-based vaccines, ii) identified unrecognised functions of platelet receptors and their regulation, offering new potential targets for pharmacological intervention and iii) developed new methodology to study the biology of megakar-yocytes (MKs), the precursor cells of platelets in the bone marrow, which lay the foundation for the modulation of platelet biogenesis and function. The projects of the CRC/TR 240 built on the unique expertise of our research network and focussed on the following complementary fields: (A) Cell bi-ology of megakaryocytes and platelets and (B) Platelets as regulators and effectors in disease. To achieve this aim, we followed a comprehensive approach starting out from in vitro systems and animal models to clinical research with large prospective patient cohorts and data-/biobanking. Despite the comparably short funding period the CRC/TR 240 discovered basic new mechanisms of platelet biogenesis, signal transduction and effector function and identified potential MK/platelet-specific molecular targets for diagnosis and therapy of thrombotic, haemorrhagic and thrombo-inflammatory disease states.
Hintergrund und Ziel
Telemedizinische Schlaganfall-Netzwerke tragen dazu bei, die Schlaganfallversorgung und insbesondere den Zugang zu zeitkritischen Schlaganfalltherapien in vorrangig strukturschwachen, ländlichen Regionen zu gewährleisten. Ziel ist eine Darstellung der Nutzungsfrequenz und regionalen Verteilung dieser Versorgungsstruktur.
Methoden
Die Kommission „Telemedizinische Schlaganfallversorgung“ der Deutschen Schlaganfall-Gesellschaft führte eine Umfragestudie in allen Schlaganfall-Netzwerken durch.
Ergebnisse
In Deutschland sind 22 telemedizinische Schlaganfall-Netzwerke aktiv, welche insgesamt 43 Zentren (pro Netzwerk: Median 1,5, Interquartilsabstand [IQA] 1–3) sowie 225 Kooperationskliniken (pro Netzwerk: Median 9, IQA 4–17) umfassen und an einem unmittelbaren Zugang zur Schlaganfallversorgung für 48 Mio. Menschen teilhaben. Im Jahr 2018 wurden 38.211 Telekonsile (pro Netzwerk: Median 1340, IQA 319–2758) durchgeführt. Die Thrombolyserate betrug 14,1 % (95 %-Konfidenzintervall 13,6–14,7 %), eine Verlegung zur Thrombektomie wurde bei 7,9 % (95 %-Konfidenzintervall 7,5–8,4 %) der ischämischen Schlaganfallpatienten initiiert. Das Finanzierungssystem ist uneinheitlich mit einem Vergütungssystem für die Zentrumsleistungen in nur drei Bundesländern.
Diskussion
Etwa jeder 10. Schlaganfallpatient wird telemedizinisch behandelt. Die telemedizinischen Schlaganfall-Netzwerke erreichen vergleichbar hohe Lyseraten und Verlegungen zur Thrombektomie wie neurologische Stroke-Units und tragen zur Sicherstellung einer flächendeckenden Schlaganfallversorgung bei. Eine netzwerkübergreifende Sicherstellung der Finanzierung und einheitliche Erhebung von Qualitätssicherungsdaten haben das Potenzial diese Versorgungsstruktur zukünftig weiter zu stärken.
Elevated and low blood pressure (BP) may lead to poor functional outcome after ischemic stroke, which is conflicting. Hence, there must be another factor—such as cerebral small vessel disease (cSVD) -interacting with BP and thus, affecting outcome. Here, we investigate the relationship between BP and cSVD regarding outcome after stroke. Data of 423/503 stroke patients were prospectively analyzed. Diastolic (DBP) and systolic BP (SBP) were collected on hospital admission (BP\(_{ad}\)) and over the first 72 h (BP\(_{72h}\)). cSVD-burden was determined on MR-scans. Good functional outcome was defined as a modified Rankin Scale score ≤ 2 at hospital discharge and 12 months thereafter. cSVD was a predictor of poor outcome (OR 2.8; p < 0.001). SBPad, DBP\(_{ad}\) and SBP\(_{72h}\) were not significantly associated with outcome at any time. A significant relationship was found between DBP\(_{72h}\), (p < 0.01), cSVD (p = 0.013) and outcome at discharge. At 12 months, we found a relationship between outcome and DBP\(_{72h}\) (p = 0.018) and a statistical tendency regarding cSVD (p = 0.08). Changes in DBP72h were significantly related with outcome. There was a U-shaped relationship between DBP\(_{72h}\) and outcome at discharge. Our results suggest an individualized stroke care by either lowering or elevating DBP depending on cSVD-burden in order to influence functional outcome.
Now that mechanical thrombectomy has substantially improved outcomes after large-vessel occlusion stroke in up to every second patient, futile reperfusion wherein successful recanalization is not followed by a favorable outcome is moving into focus. Unfortunately, blood-based biomarkers, which identify critical stages of hemodynamically compromised yet reperfused tissue, are lacking. We recently reported that hypoxia induces the expression of endoglin, a TGF-β co-receptor, in human brain endothelium in vitro. Subsequent reoxygenation resulted in shedding. Our cell model suggests that soluble endoglin compromises the brain endothelial barrier function. To evaluate soluble endoglin as a potential biomarker of reperfusion (-injury) we analyzed its concentration in 148 blood samples of patients with acute stroke due to large-vessel occlusion. In line with our in vitro data, systemic soluble endoglin concentrations were significantly higher in patients with successful recanalization, whereas hypoxia alone did not induce local endoglin shedding, as analyzed by intra-arterial samples from hypoxic vasculature. In patients with reperfusion, higher concentrations of soluble endoglin additionally indicated larger infarct volumes at admission. In summary, we give translational evidence that the sequence of hypoxia and subsequent reoxygenation triggers the release of vasoactive soluble endoglin in large-vessel occlusion stroke and can serve as a biomarker for severe ischemia with ensuing recanalization/reperfusion.
Effect of Tjap1 knock-down on blood-brain barrier properties under normal and hypoxic conditions
(2023)
Stroke is one of the leading causes of mortality and disability worldwide. The blood-brain barrier (BBB) plays an important role in maintaining brain homeostasis by tightly regulating the exchange of substances between circulating blood and brain parenchyma. BBB disruption is a common pathologic feature of stroke and traumatic brain injury. Understanding the cellular and molecular events that affect the BBB after ischaemic brain injury is important to improve patient prognosis.
We have previously shown that microRNA-212/132 is elevated in hypoxic brain microvascular endothelial cells and acts through suppressing the expression of direct microRNA-212/132 target genes with function at the BBB: claudin-1, junctional adhesion molecule 3 (Jam3) and tight-junction associated protein 1 (Tjap1). While the role of claudin-1 and Jam3 at the BBB is well known, the role of Tjap1 is still unclear. The aim of this work was therefore to characterize the role of Tjap1 in brain endothelial cells using a knock-down (KD) approach in established murine in vitro BBB models cEND and cerebEND. Tjap1 KD was established by stable transfection of a plasmid expressing shRNA against Tjap1. The successful downregulation of Tjap1 mRNA and protein was demonstrated by qPCR and Western blot. Tjap1 KD resulted in impaired barrier properties of endothelial cells as shown by lower TEER values and higher paracellular permeability. Interestingly, the Tjap1 KD cells showed lower cell viability and proliferation but migrated faster in a wound healing assay. In the tube formation assay, Tjap1 KD cell lines showed a lower angiogenic potential due to a significantly lower tube length and number as well as a lower amount of branching points in formed capillaries. Tjap1 KD cells showed changes in gene and protein expression. The TJ proteins claudin-5, Jam3 and ZO-1 were significantly increased in Tjap1 KD cell lines, while occludin was strongly decreased. In addition, efflux pump P-glycoprotein was downregulated in Tjap1 KD cells. Oxygen-glucose deprivation (OGD) is a method to mimic stroke in vitro. Brain endothelial cell lines treated with OGD showed lower barrier properties compared to cells cultured under normal condition. These effects were more severe in Tjap1 KD cells, indicating active Tjap1 involvement in the OGD response in brain microvascular endothelial cells.
We thus have shown that Tjap1 contributes to a tight barrier of the BBB, regulates cell viability and proliferation of endothelial cells, suppresses their migration and promotes new vessel formation. This means that Tjap1 function is important for mature BBB structure in health and disease.
Background
Long-term support of stroke patients living at home is often delivered by family caregivers (FC). We identified characteristics of stroke patients being associated with receiving care by a FC 3-months (3 M) after stroke, assessed positive and negative experiences and individual burden of FC caring for stroke patients and determined factors associated with caregiving experiences and burden of FC 3 M after stroke.
Methods
Data were collected within TRANSIT-Stroke, a regional telemedical stroke-network comprising 12 hospitals in Germany. Patients with stroke/TIA providing informed consent were followed up 3 M after the index event. The postal patient-questionnaire was accompanied by an anonymous questionnaire for FC comprising information on positive and negative experiences of FC as well as on burden of caregiving operationalized by the Caregiver Reaction Assessment and a self-rated burden-scale, respectively. Multivariable logistic and linear regression analyses were performed.
Results
Between 01/2016 and 06/2019, 3532 patients provided baseline and 3 M-follow-up- data and 1044 FC responded to questionnaires regarding positive and negative caregiving experiences and caregiving burden. 74.4% of FC were older than 55 years, 70.1% were women and 67.5% were spouses. Older age, diabetes and lower Barthel-Index in patients were significantly associated with a higher probability of receiving care by a FC at 3 M. Positive experiences of FC comprised the importance (81.5%) and the privilege (70.0%) of caring for their relative; negative experiences of FC included financial difficulties associated with caregiving (20.4%). Median overall self-rated burden was 30 (IQR: 0–50; range 0–100). Older age of stroke patients was associated with a lower caregiver burden, whereas younger age of FC led to higher burden. More than half of the stroke patients in whom a FC questionnaire was completed did self-report that they are not being cared by a FC. This stroke patient group tended to be younger, more often male with less severe stroke and less comorbidities who lived more often with a partner.
Conclusions
The majority of caregivers wanted to care for their relatives but experienced burden at the same time. Elderly patients, patients with a lower Barthel Index at discharge and diabetes are at higher risk of needing care by a family caregiver.
Trial registration
The study was registered at “German Clinical Trial Register”: DRKS00011696. https://www.drks.de/drks_web/navigate.do?navigationId=trial.HTML&TRIAL_ID=DRKS00011696
The blood-brain barrier (BBB) is a highly specialized structure that separates the brain from the blood and allows the exchange of molecules between these two compartments through selective channels. The breakdown of the BBB is implicated in the development of severe neurological diseases, especially stroke and traumatic brain injury. Oxygen-glucose deprivation is used to mimic stroke and traumatic brain injury in vitro. Pathways that trigger BBB dysfunction include an imbalance of oxidative stress, excitotoxicity, iron metabolism, cytokine release, cell injury, and cell death. MicroRNAs are small non-coding RNA molecules that regulate gene expression and are emerging as biomarkers for the diagnosis of central nervous system (CNS) injuries. In this review, the regulatory role of potential microRNA biomarkers and related therapeutic targets on the BBB is discussed. A thorough understanding of the potential role of various cellular and linker proteins, among others, in the BBB will open further therapeutic options for the treatment of neurological diseases.
In large vessel occlusion stroke, recanalization to restore cerebral perfusion is essential but not necessarily sufficient for a favorable outcome. Paradoxically, in some patients, reperfusion carries the risk of increased tissue damage and cerebral hemorrhage. Experimental and clinical data suggest that endothelial cells, representing the interface for detrimental platelet and leukocyte responses, likely play a crucial role in the phenomenon referred to as ischemia/reperfusion (I/R)-injury, but the mechanisms are unknown. We aimed to determine the role of endoglin in cerebral I/R-injury; endoglin is a membrane-bound protein abundantly expressed by endothelial cells that has previously been shown to be involved in the maintenance of vascular homeostasis. We investigated the expression of membranous endoglin (using Western blotting and RT-PCR) and the generation of soluble endoglin (using an enzyme-linked immunosorbent assay of cell culture supernatants) after hypoxia and subsequent reoxygenation in human non-immortalized brain endothelial cells. To validate these in vitro data, we additionally examined endoglin expression in an intraluminal monofilament model of permanent and transient middle cerebral artery occlusion in mice. Subsequently, the effects of recombinant human soluble endoglin were assessed by label-free impedance-based measurement of endothelial monolayer integrity (using the xCELLigence DP system) and immunocytochemistry. Endoglin expression is highly inducible by hypoxia in human brain endothelial monolayers in vitro, and subsequent reoxygenation induced its shedding. These findings were corroborated in mice during MCAO; an upregulation of endoglin was displayed in the infarcted hemispheres under occlusion, whereas endoglin expression was significantly diminished after transient MCAO, which is indicative of shedding. Of note is the finding that soluble endoglin induced an inflammatory phenotype in endothelial monolayers. The treatment of HBMEC with endoglin resulted in a decrease in transendothelial resistance and the downregulation of VE-cadherin. Our data establish a novel mechanism in which hypoxia triggers the initial endothelial upregulation of endoglin and subsequent reoxygenation triggers its release as a vasoactive mediator that, when rinsed into adjacent vascular beds after recanalization, can contribute to cerebral reperfusion injury.