TY  - THES
A1  - Leinweber, Jonas
T1  - Untersuchung zur pathophysiologischen Rolle und therapeutischen Relevanz der neuen Inhibitoren der plasmatischen Blutgerinnung Agaphelin und Ixolaris im experimentellen Schlaganfallmodell der Maus
T1  - Characterization of the pathophysiological role and therapeutic relevance of the new inhibitors of plasmatic blood coagulation Agaphelin and Ixolaris in the model of ischemic stroke in mice
N2  - Beim ischämischen Schlaganfall führt ein thrombotischer Verschluss von gehirnversorgenden Arterien zu einer akuten Durchblutungsstörung, mit der Folge von neurologischen Defiziten. Primäres Therapieziel ist es, diese Blutgerinnsel aufzulösen, um die Sauerstoffversorgung des Gehirns wiederherzustellen und den ischämischen Hirnschaden zu begrenzen. Dazu stehen die intravenösen Thrombolyse mit rt-PA (rekombinanter Gewebe-Plasminogen-Aktivator) sowie die endovaskuläre mechanische Thrombektomie zur Verfügung. Häufig kann ein Schlaganfall, trotz erfolgreicher Rekanalisation der Gefäße, zu einer weiteren Größenzunahme des Infarktes und neurologischen Defiziten bei den Patienten führen. Diese Größenzunahme beruht zum einen auf einem sich entwickelnden Hirnödem und zum anderen auf entzündlichen Prozessen. Zahlreiche Hinweise deuten darauf hin, dass der Schlaganfall ein Zusammenspiel aus thrombotischen und entzündlichen Ereignissen ist, ein Phänomen, das als Thromboinflammation bezeichnet wird. Aufgrund der begrenzten Behandlungsmöglichkeiten ist die Entwicklung neuer Therapieansätze für den ischämischen Schlaganfall besonders wichtig. Agaphelin und Ixolaris sind Proteine aus den Speicheldrüsen von Hämatophagen, für welche in früheren Studien eine starke antithrombotische Wirkung bei gleichzeitig geringem Blutungsrisiko nachgewiesen wurde. Diese möglichen antithrombotischen Effekte wurden in dieser Studie im Hinblick auf ihre Wirksamkeit und Sicherheit im Mausmodell der zerebralen Ischämie untersucht. Die Behandlung der Mäuse mit Agaphelin 1 Stunde nach transienter Okklusion der Arteria cerebri media (tMCAO) führte zu kleineren Schlaganfallvolumina und geringeren neurologischen Defiziten an Tag 1 nach dem Schlaganfall. Die Mortalität der Mäuse war bis Tag 7 deutlich gesunken. Aus klinischer Sicht ist ebenfalls relevant, dass der starke antithrombotische Effekt von Agaphelin im Mausmodell nicht mit einem erhöhten Risiko für intrazerebrale Blutungen einherging. Diesem protektiven Effekt von Agaphelin lagen eine verminderte intrazerebrale Thrombusbildung, eine abgeschwächte Entzündungsantwort und eine Stabilisierung der Blut-Hirn-Schranke sowie eine Reduzierung der Apoptose zugrunde. Nach der Gabe von Ixolaris 1 Stunde nach tMCAO waren zwar signifikant geringere Infarktgrößen messbar, diese führten allerdings nicht zu einer Verbesserung der neurologischen Defizite. Zudem verursachte die Gabe von Ixolaris schon 24 Stunden nach tMCAO erhebliche intrazerebrale Blutungen und auch die Mortalität der Mäuse war zu diesem Zeitpunkt bereits erhöht. Aufgrund dieser massiven Nebenwirkungen scheint Ixolaris kein geeigneter Kandidat für eine humane Anwendung zu sein. Bei Agaphelin hingegen könnte es  
sich um einen vielversprechenden Kandidaten für die Behandlung des ischämischen Schlaganfalls handeln. Vor einer möglichen Testung von Agaphelin in klinischen Studien, sind weitere translationale Untersuchungen notwendig, um ein noch präziseres Verständnis für die Wirksamkeit und Sicherheit von Agaphelin zu gewinnen. Insgesamt stellt die Hemmung thromboinflammatorischer Prozesse, ohne eine Erhöhung der Blutungskomplikationen, eine vielversprechende Option zur Behandlung des ischämischen Schlaganfalls dar.
N2  - Thrombotic occlusion of cerebral vessels is an important process in pathogenesis of ischemic stroke resulting in lack of blood supply of the brain and neurological deficits. In order to restore the oxygenation of the brain and to limit brain injury, recanalization of the occluded vessels is the therapeutic main goal of stroke treatment. So far, the only proven pharmacological intervention for thrombolysis is the recombinant tissue-type plasminogen activator. For recanalization of larger arteries endovascular thrombectomy was established as a mechanic intervention. Nevertheless, despite successful recanalization ischemic brain damage and neurological deficits evolve. Increased size of infarct lesions develop due to brain edema and inflammatory processes. Moreover, there is evidence that inflammation and thrombosis are linked, which has led to the concept of thromboinflammation. Due to the limited treatment strategies in stroke management, the development of new therapeutic approaches for ischemic stroke is particularly important. Recent studies have shown that the hematophagous salivary gland proteins Agaphelin and Ixolaris exhibit multiple antithrombotic effects without promoting a risk of bleeding. To investigate the potentially safe antithrombotic effects, Agaphelin and Ixolaris were tested in a mouse model of transient middle cerebral artery occlusion (tMCAO). Treatment of mice with Agaphelin 1 hour after tMCAO resulted in smaller infarct volumes and an improved neurological function on day one after stroke. Up to seven days after stroke the mortality rate was significantly reduced. This protective effect was due to reduced local thrombus formation, a reduced inflammatory response and less severe blood-brain-barrier damage as well as reduced apoptosis. Moreover, it is important to mention, that the strong protective effect of Agaphelin was not linked to an increased risk of intracerebral bleeding. Treatment of mice with Ixolaris one hour after tMCAO leads to significantly smaller infarct sizes. However, neurologic deficits did not improve after treatment with Ixolaris. Furthermore, risk of intracerebral bleeding and mortality rates were significantly increased 24 hours after treatment with Ixolaris. Due to these severe side effects, Ixolaris does not seem to be an appropriate candidate for human therapy. Nevertheless, Agaphelin appears to be a promising component for ischemic stroke treatment, but further translational studies should be performed before testing Agaphelin in clinical stroke trials. Overall, the inhibition of thromboinflammatory effects without increased bleeding reflects a promising option for successful ischemic stroke treatment.
KW  - Schlaganfall
KW  - antithrombotic
KW  - inflammation
KW  - stroke
KW  - Agaphelin
KW  - Ixolaris
KW  - Thromboinflammation
KW  - Experimenteller Schlaganfall
Y1  - 2022
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-252921
ER  - 
TY  - JOUR
A1  - Haberstumpf, Sophia
A1  - Forster, André
A1  - Leinweber, Jonas
A1  - Rauskolb, Stefanie
A1  - Hewig, Johannes
A1  - Sendtner, Michael
A1  - Lauer, Martin
A1  - Polak, Thomas
A1  - Deckert, Jürgen
A1  - Herrmann, Martin J.
T1  - Measurement invariance testing of longitudinal neuropsychiatric test scores distinguishes pathological from normative cognitive decline and highlights its potential in early detection research
JF  - Journal of Neuropsychology
N2  - Objective
Alzheimer’s disease (AD) is a growing challenge worldwide, which is why the search for early-onset predictors must be focused as soon as possible. Longitudinal studies that investigate courses of neuropsychological and other variables screen for such predictors correlated to mild cognitive impairment (MCI). However, one often neglected issue in analyses of such studies is measurement invariance (MI), which is often assumed but not tested for. This study uses the absence of MI (non-MI) and latent factor scores instead of composite variables to assess properties of cognitive domains, compensation mechanisms, and their predictability to establish a method for a more comprehensive understanding of pathological cognitive decline.
Methods
An exploratory factor analysis (EFA) and a set of increasingly restricted confirmatory factor analyses (CFAs) were conducted to find latent factors, compared them with the composite approach, and to test for longitudinal (partial-)MI in a neuropsychiatric test battery, consisting of 14 test variables. A total of 330 elderly (mean age: 73.78 ± 1.52 years at baseline) were analyzed two times (3 years apart).
Results
EFA revealed a four-factor model representing declarative memory, attention, working memory, and visual–spatial processing. Based on CFA, an accurate model was estimated across both measurement timepoints. Partial non-MI was found for parameters such as loadings, test- and latent factor intercepts as well as latent factor variances. The latent factor approach was preferable to the composite approach.
Conclusion
The overall assessment of non-MI latent factors may pose a possible target for this field of research. Hence, the non-MI of variances indicated variables that are especially suited for the prediction of pathological cognitive decline, while non-MI of intercepts indicated general aging-related decline. As a result, the sole assessment of MI may help distinguish pathological from normative aging processes and additionally may reveal compensatory neuropsychological mechanisms.
KW  - Alzheimer’s disease
KW  - early-onset predictors
KW  - mild cognitive impairment
Y1  - 2022
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-318932
VL  - 16
IS  - 2
SP  - 324
EP  - 352
ER  - 
TY  - JOUR
A1  - Haberstumpf, Sophia
A1  - Leinweber, Jonas
A1  - Lauer, Martin
A1  - Polak, Thomas
A1  - Deckert, Jürgen
A1  - Herrmann, Martin J.
T1  - Factors associated with dropout in the longitudinal Vogel study of cognitive decline
JF  - The European Journal of Neuroscience
N2  - Dementia, including Alzheimer's disease, is a growing problem worldwide. Prevention or early detection of the disease or a prodromal cognitive decline is necessary. By means of our long-term follow-up ‘Vogel study’, we aim to predict the pathological cognitive decline of a German cohort (mean age was 73.9 ± 1.55 years at first visit) with three measurement time points within 6 years per participant. Especially in samples of the elderly and subjects with chronic or co-morbid diseases, dropouts are one of the biggest problems of long-term studies. In contrast to the large number of research articles conducted on the course of dementia, little research has been done on the completion of treatment. To ensure unbiased and reliable predictors of cognitive decline from study completers, our objective was to determine predictors of dropout. We conducted multivariate analyses of covariance and multinomial logistic regression analyses to compare and predict the subject's dropout behaviour at the second visit 3 years after baseline (full participation, partial participation and no participation/dropout) with neuropsychiatric, cognitive, blood and lifestyle variables. Lower performance in declarative memory, attention and visual–spatial processing predicted dropout rather than full participation. Lower performance in visual–spatial processing predicted partial participation as opposed to full participation. Furthermore, lower performance in mini-mental status examination predicted whether subjects dropped out or participated partially instead of full participation. Baseline cognitive parameters are associated with dropouts at follow-up with a loss of impaired participants. We expect a bias into a healthier sample over time.
KW  - dementia
KW  - prevention
KW  - cognitive decline
Y1  - 2022
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-318945
VL  - 56
IS  - 9
SP  - 5587
EP  - 5600
ER  -