Pairing transcranial direct current stimulation and mindfulness meditation in the treatment of fibromyalgia

The lack of effective treatments for managing pain and associated symptoms in fibromyalgia (FM) poses both a clinical challenge and an economic burden on the health sector. Typical FM therapies include an array of pharmacological and non-pharmacological interventions. Commonly used drugs have demonstrated only mild improvements in FM while benefitting only a minority of patients. In this scenario, repeated anodal transcranial direct current stimulation (tDCS) and mindfulness-based interventions have emerged as two promising non-pharmacological treatments for pain relief and improvement of FM-associated symptoms. However, the strength and durability of the therapeutic benefits of these methods vary across studies. The combination of non-pharmacological therapies has been proposed as a way to optimise and bolster the therapeutic effects of monomodal interventions. Although the combination of tDCS and mindfulness meditation (MM) has shown synergistic effects in both healthy individuals and patients with neuropsychiatric disorders and some chronic pain conditions, it has not yet been investigated in patients with FM. The rationale behind exploring this combination was to modulate the brain state via MM, with the goal of boosting the neuroplastic effects of currently recommended conventional tDCS protocols for chronic pain. In this dissertation, the current state of the literature on combining these two methods was reviewed. A sham-controlled randomised pilot clinical study was conducted to test the preliminary therapeutic efficacy and safety of a ten-day intervention concurrently applying anodal tDCS targeting the left primary motor cortex (M1) and MM, administered as a clinicbased treatment, in patients with FM. Prior to the combined therapy, participants received a fiveday training in MM. Patients in the active tDCS group reported a larger clinically meaningful improvement in quality of life following the combined intervention, compared to those receiving sham tDCS paired with MM or treatment-as-usual. No differences in pain reduction and improvements in sleep quality or psychological well-being were observed among the groups. Building on these findings and addressing the limitations of the pilot study, we investigated the therapeutic and mechanistic impact of a ten-day treatment combining anodal tDCS over the left 8 M1 and MM on pain relief, quality of life, and associated symptoms in individuals with FM trained in mindfulness. Participants in this trial completed a four-week brief mindfulness intervention tailored for FM (BMIF) prior to randomisation. The combined treatment was administered as an at-home intervention under remote supervision. To investigate the possible underlying mechanisms, we measured changes in cortical excitability using transcranial magnetic stimulation (TMS) of the left M1. Finally, we implemented a responder analysis approach to decipher the effects of the BMIF and the add-on combination of tDCS and MM with regard to emotion regulation (ER), which is one of the primary targets mediating improvement in symptom burden and management in FM. Although patients showed improvements in clinical symptoms, no superior therapeutic benefits were observed when pairing MM with anodal tDCS, compared to the combination of MM with sham tDCS. Both groups demonstrated substantial and acute pain relief and improvements in quality of life, sleep quality, affect, and psychological well-being following the combined intervention. The lack of group differences in TMS metrics failed to provide meaningful insights into the potential synergistic mechanisms of tDCS and MM. Interestingly, clinical responders to the combined intervention in the active tDCS group exhibited impaired ER compared to the sham group, even suggesting potential antagonistic effects of pairing M1-tDCS with MM for ER. Moreover, the reduction of the cortical excitability of the left M1, likely mediated by daily MM practice, might block the mechanistic consequences of anodal tDCS of the left M1. On the other hand, the nonspecific main effect of time in clinical outcomes, alongside a large significant increase in mindfulness over time, hints at a potential ‘mindfulness effect’, in line with previous studies showing that longer MM practice results in greater therapeutic benefits in FM. The introduction of the Medical Device Regulation in 2021 and the recent reclassification of some of the non-invasive brain stimulation (NIBS) devices (for example, tDCS and TMS) to the same risk level as invasive deep brain stimulation in the European Union have imposed a considerable hindrance to the research and further development of tDCS. A multinational participatory study including different stakeholders involved in the consumption, use, manufacturing, and regulation of NIBS was conducted to address the clinical, academic, legal, ethical, and social concerns surrounding NIBS. The different stakeholders’ perspectives were analysed and compiled to draft a set of recommendations for the use and regulation of NIBS, including tDCS in the European subcontinent. To improve the accessibility of tDCS to patients, 9 the optimisation of currently available NIBS treatments via broader administration and further development of home-based tDCS as well as personalisation of therapy have been suggested by the stakeholders. Stricter regulation of tDCS for non-medical reasons and research focused on higher effectiveness of tDCS, underlying mechanisms, and development of responders were also proposed, among others. Taken together, our work challenges the combination of M1-tDCS and MM as a strategy to optimise tDCS treatment for pain relief and symptom improvement in patients with FM. However, this dissertation highlights the pivotal role of clinical research regarding combined interventions, whereby two therapies beneficial on their own might not necessarily be more effective when combined. Future research should explore the additional effect of combining MM and tDCS compared to tDCS and MM alone and delve deeper into the workings of the combined intervention using more sophisticated neuroimaging tools, with the goal of developing novel and individualised methods to optimise the currently available NIBS technologies for the treatment of FM.2025-08-1

Obesity and Ageing: accelerators of cognitive decline in melanocortin 4 receptor-deficient mice

Genetic or lifestyle-related obesity ails almost one billion people worldwide. Obesity is an accumulation of fat, while, ageing is an ongoing process of accumulation of harmful molecular alterations. Obesity and ageing, independently, contribute to the pathology of neurodegenerative diseases. Interestingly, with co-progression they enhance each other and accelerate the onset of diseases. Usually, neurodegenerative diseases appear in late-age and revealing ongoing irreversible damage in the CNS. Therefore, in this project, I sought to investigate the consequences of obese-ageing on cognitive decline and deduce an early candidate biomarker of cognitive decline. In this study, I analysed the cognitive abilities of Mc4r-deficient obese mice aged 6-9 months (here referred to as 6-months-old) and 12-15 months (here referred to as 1-year-old) using a battery of behaviour tests. Open field, novel object recognition, and water-maze test were performed, to gauge the cognitive abilities of the obese mice vs. lean litter-mates. Following behaviour tests, molecular, and immuno-histological analyses were performed, with brain samples harvested from all cohorts. Additionally, immuno-assays were performed for serological analyses. 1-year-old obese mice showed a behavioral phenotype of cognitive deficit. Subsequent macroscopic and microscopic analyses indicated that obese mice harbour cerebral atrophy and therefore dilated lateral ventricles. Axonal damage was confirmed by analysing sera neurofilament light chain in the 1-year old obese mice. Further immunoassay of sera confirmed systemic inflammation in 6-month and 1-year-old obese mice. Adipose hypertrophy and hyperplasia produces enhanced levels of pro-inflammatory factors causing chronic systemic inflammation. Systemic inflammation, in addition to the lipid influx through a leaky blood-brain-barrier, elicits an immune response in the brain. This neuroinflammation in the brain was confirmed by increased presence of microglia in the 1-year-old obese mice. Furthermore, an mRNA sequencing profile of hippocampus of 1-year-old obese mice was procured. The transcriptional data revealed a number of differentially expressed genes that are suspected to play an important role in cognitive decline associated to obese-ageing. Secreted phosphoprotein 1 (Spp1) a.k.a. osteopontin, was screened as a potential early candidate biomarker of cognitive decline. Spp1 has an upregulated gene expression in the hippocampus of obese mice along with increased presence in the sera of obese mice. Overall, my work suggests that obese-ageing accelerates the onset of cognitive decline with a likelihood to transform into neurodegeneration. Based on preliminary data, Spp1 appears to be a promising early cognitive decline marker. Therefore, further investigation of Spp1, including in humans, has the potential to offer an interesting prospect towards having a promising cognitive decline marker.2025-06-1

NTRK alterations in non-small cell lung cancer

Alterationen, insbesondere Genfusionen, der NTRK-Genfamilie, bestehend aus NTRK1, NTRK2 und NTRK3, stellen einen seltenen, aber therapeutisch potentiell adressierbaren Treiber in nicht-kleinzelligen Lungenkarzinomen dar. Durch Alterationen bedingte konstitutive Aktivierung oder Überexpression der durch sie kodierten Tropomyosin-related-Kinasen (respektive TrkA, TrkB und TrkC) können deren physiologische Effekte wie Zellproliferation und Apoptosehemmung zu einem unkontrollierten Zellwachstum und damit zur Kanzerogenese führen. Die niedrige Prävalenz der therapeutisch adressierbaren NTRK-Genfusionen bedingt die Herausforderung der Molekularpathologie, dieses seltene Phänomen zuverlässig zu erkennen, um den entsprechenden Patient*innen die hocheffektive Therapie mit einem spezifischen Tyrosinkinaseinhibitor zukommen zu lassen. Alterationen anderer Art wie Spleißvarianten, Amplifikationen oder Punktmutationen sind ebenfalls beschrieben, in ihrer Expression und ihrem Effekt auf die Onkogenese jedoch nicht eindeutig klassifiziert. Für diese Arbeit wurde eine Kohorte von 1.080 konsekutiven, nicht vorselektierten Fälle nicht-kleinzelliger Lungenkarzinome, die zwischen Dezember 2016 und Juni 2018 im Institut für Pathologie der Universitätsmedizin Göttingen bearbeitet wurden, mittels unterschiedlicher Methoden auf NTRK-Alterationen untersucht. Der Großteil der Fälle erhielt zunächst eine immunhistochemische Testung auf eine Trk-Expression, die bei Positivität durch eine Testung der Ursache mit RNA-basierter next generation-Sequenzierung und/ oder Fluoreszenz-in situ-Hybridisierung ergänzt wurde. Auch einige immunhistochemisch negative Fälle wurden zur Vergleichbarkeit mit diesen Methoden untersucht. Neben der vorausgegangenen Klassifizierung der Immunhistochemie in „positiv“ und „negativ“ wurden Intensität und subzelluläre Lokalisation der Färbung im Rahmen dieser Arbeit mittels eines Scores beurteilt und sortiert. Ein anderer Teil der Fälle wurde als einzige Methode per Fluoreszenz-in situ-Hybridisierung untersucht. In 23 Fällen (2,1%) konnte eine Alteration jeglicher Art von NTRK1, -2- oder -3 ermittelt werden. Genfusionen traten mit zwei Fällen zu 0,19% auf: Eine SQSTM1-NTRK1- und eine EPS15-NTRK1-Fusion wurden in zwei Adenokarzinomen männlicher Patienten identifiziert und ihre Träger einer Tyrosinkinaseinhibitortherapie zugeführt. Immunhistochemisch zeigten sich beide Fälle stark positiv (Rang 1 und 7 unter 169 positiven Fällen) und wiesen in anderen prominenten Treibern (EGFR, KRAS, ALK, ROS1, RET, MET) keine Mutationen auf, was die NTRK-Fusion als primären Treiber wahrscheinlich macht. Zehn Fälle wiesen in der Fluoreszenz-in situ-Hybridisierung eine Vermehrung der Kopienzahl (über vier) eines oder mehrerer NTRK-Gene auf, die zu 90% mit einer immunhistochemischen Positivität einherging. In insgesamt zwölf Fällen konnten alternative Spleißvarianten der drei Trk-Proteine nachgewiesen werden, darunter sieben Fälle eines Exon 12-skippings (zu 85,7% immunhistochemisch positiv) und drei Fälle eines Exon 10-skippings (100% immunhistochemisch positiv) jeweils von NTRK2. Der Krankheitswert der Spleißvarianten und Genkopienzahlerhöhungen lässt sich mit den vorliegenden Daten nicht eindeutig bestimmen und ist auch im Literaturkontext Gegenstand von Diskussionen. Während sich die alleinige Testung auf Translokationen per Fluoreszenz-in situ-Hybridisierung als zu zeit- und materialaufwändig in einer Kohorte mit so niedriger Prävalenz zeigte, erwies sich ein Vorgehen mit primärer Immunhistochemie und sequentieller RNA-basierter next generation-Sequenzierung als zuverlässig, um die vorliegenden NTRK-Fusionen und -Spleißvarianten zu erkennen. Für das Ermitteln von Amplifikationen war die FISH eine geeignetere, wenn auch nicht ideale Methode. Im Kontext der aktuellsten Literatur wird für NTRK-Alterationen in nicht-kleinzelligen Lungenkarzinomen eine RNA-basierte Nachweismethode favorisiert. Spleißvarianten und Amplifikationen von NTRK sollten als potentiell adressierbare Mutationen näher auf ihr onkogenes Potenzial und therapeutische Adressierbarkeit untersucht werden.Alterations, especially gene fusions, of the NTRK gene family, consisting of NTRK1, NTRK2 and NTRK3, represent a rare, but therapeutically potentially addressable driver in non-small cell lung carcinomas. Constitutive activation or overexpression caused by alterations of the tropomyosin-related kinases encoded by them (respectively TrkA, TrkB, and TrkC) can lead to uncontrolled cell growth and thus to carcinogenesis due to their physiological effects such as cell proliferation and apoptosis inhibition. The low prevalence of therapeutically addressable NTRK gene fusions makes it challenging for molecular pathology to reliably detect this rare phenomenon in order to offer the corresponding patients the highly effective therapy with a specific tyrosine kinase inhibitor. Alterations of other kinds, such as splice variants, amplifications, or point mutations, are also described, but their expression and effect on oncogenesis are not clearly classified. For this study, a cohort of 1080 consecutive, non-preselected cases of non-small cell lung carcinomas that were treated at the Institute of Pathology at the University of Göttingen between December 2016 and June 2018, were examined for NTRK alterations using different methods. Most of the cases initially underwent immunohistochemical testing for Trk expression, which, if positive, was supplemented by testing the cause with RNA-based next generation sequencing and/or fluorescence in situ hybridization. Some immunohistochemically negative cases were also examined using these methods for comparability. In addition to the prior classification of immunohistochemistry into "positive" and "negative", the intensity and subcellular location of the staining were evaluated and sorted using a score in the context of this work. Another part of the cases was examined by fluorescence in situ hybridization as the only method. An alteration of any kind of NTRK1, -2, or -3 was determined in 23 cases (2.1%). Gene fusions occurred in two cases at 0.19 %: A SQSTM1-NTRK1 and EPS15-NTRK1 fusion was identified in two adenocarcinomas in male patients and their carriers were given tyrosine kinase inhibitor therapy. Immunohistochemically, both cases showed strongly positive (rank 1 and 7 among 169 positive cases) and did not show mutations in other prominent drivers (EGFR, KRAS, ALK, ROS1, RET, MET), which likely makes the NTRK fusion the primary driver. Ten cases showed an increase in copy number (above four) of one or more NTRK genes in fluorescence in situ hybridization, which was associated with immunohistochemical positivity in 90 %. In a total of twelve cases, alternative splice variants of the three Trk proteins could be detected, including seven cases of exon 12 skipping (85.7% immunohistochemically positive) and three cases of exon 10 skipping (100% immunohistochemically positive) each of NTRK2. The disease value of splice variants and increased gene copy numbers cannot be determined conclusively with the available data and is also a subject of discussion in the literature. While testing only for translocations by fluorescence in situ hybridization proved to be too time-consuming and material-consuming in a cohort with such low prevalence, an approach with primary immunohistochemistry and sequential RNA-based next generation sequencing proved to be reliable in detecting the present NTRK fusions and splice variants. For the detection of amplifications, FISH was a more suitable, if not ideal method. In the context of the latest literature, an RNA-based detection method is favored for NTRK alterations in non-small cell lung carcinomas. Splice variants and amplifications of NTRK should be closely examined for their oncogenic potential and therapeutic addressability as potentially addressable mutations.2025-04-2

Anatomical outcomes and complication rates after macular hole surgery

Das durchgreifende Makulaforamen ist kein sehr häufiges Krankheitsbild, es ist jedoch visusbedrohend und ohne Therapie ist die Gefahr eines dauerhaften und schwerwiegenden Sehverlusts hoch. Die aktuell einzige etablierte und standardmäßig durchgeführte Therapie für das durchgreifende Makulaforamen stellt die operative Intervention mittels Vitrektomie dar. Ziel dieser Arbeit war es, eine Übersicht über Komplikations- und Re-Operationsraten zu geben, sowie die Evaluation der eigenen Operationsleistung an der Augenklinik der Universitätsmedizin Göttingen. Zu diesem Zweck wurden 400 Patienten mit durchgreifendem Makulaforamen in die retrospektive Studie eingeschlossen. Der primäre Lochverschluss nach initialer Operation wurde in 73,3 % der Fälle erreicht. Die Reoperationsrate betrug 22,5 %. Insgesamt haben sich 94,7 % aller Makulaforamina abschließend verschlossen. Als statistisch signifikante Einflussfaktoren auf den primären Lochverschluss wurden in dieser Studie das Alter der Patienten, die Foramengröße, die Art der verwendeten Endotamponade und die Kombination der Vitrektomie mit einer Katarakt-Extraktion gefunden. Postoperative Komplikationen, neben dem persistierenden Makulaforamen (25,25 %), waren ein erhöhter Augeninnendruck > 30 mmHg (19,5 %) und die Netzhautablösung (3,35 %). Die übrigen untersuchten postoperativen Komplikationen, vor allem das wiedereröffnete Makulaforamen (2,25 %) waren selten.The full thickness macular hole is a vision threatening condition and without treatment the risk of permanent and severe vision loss is high. Currently, the only established and standard treatment for full thickness macular holes is vitrectomy with peeling of internal limiting membrane. The purpose of this retrospective analysis was to examine the anatomical outcome (macular hole closure rate), complication rates and reoperation rates after macular hole surgery. Data of 400 patients with full thickness macular holes were included. Macular hole closure after initial surgery was achieved in 73,3% of cases. 22,5% of patients had to undergo one or more reoperations. 94,7% of all macular holes finally closed. In this study, the patient's age, foramen size, the type of endotamponade and the combination of vitrectomy with cataract extraction had statistically significant influence on anatomical outcome and development of persistent macular holes. Postoperative complications, besides the persistent macular hole (25,25%), were elevated intraocular pressure > 30 mmHg (19,5%) and retinal detachment (3,35%). Other postoperative complications, especially reopened macular holes (1,25%), were rare.2025-05-2

Retinal Vascular Occlusion after COVID-19 Vaccination: More Coincidence than Causal Relationship? Data from a Retrospective Multicentre Study

Führt eine COVID-19 Impfung zu einem retinalen Gefäßverschlusses? - Eine multizentrische Erhebung an deutschen Augenzentren. Hintergrund: Untersucht werde sollte ein möglicher Zusammenhang zwischen dem Auftreten von retinalen Gefäßverschlüssen und einer Impfung gegen SARS-CoV2. Methoden: Diese multizentrische Erhebung an deutschen Augenkliniken wurde im Namen der Retinologischen Gesellschaft durchgeführt. Dazu wurde ein online-Formular zur anonymisierten Patientendateneingabe bereitgestellt. Eingeschlossen wurden Patienten mit Zentralvenenverschluss (ZVV), Venenastverschluss (VAV), Zentralarterienverschluss (ZAV), Arterienastverschluss (AAV) oder einer anteriore ischämische Optikusneuropathie (AION). Die Diagnose musste zwischen dem 01.06.2021 und dem 31.07.2021 gestellt worden sein, der Zeitpunkt der ersten Symptome durfte nicht länger als 12 Wochen zurückliegen. Ein Zusammenhang galt als wahrscheinlich, wenn der Verschluss innerhalb von vier Wochen nach der COVID-19 Impfung eintrat. Neben einer reinen Fallanalyse wurde der Datensatz zusätzlich im Rahmen einer Fall-Kontroll-Studie mit Daten der Gutenberg-Gesundheitsstudie (GHS) analysiert, um regionale und zeitliche Häufungen auszugleichen. Ergebnisse: 36 der 50 ophthalmologischen Zentren haben sich an der Erhebung beteiligt, insgesamt wurden Datensätze von 515 Patienten eingegeben, bei 421 lagen alle studienrelevanten Daten vor. 332 (78,9%) der Patienten waren mindestens einmal geimpft. 306 (76,7%) der Patienten stellten sich innerhalb von zwei Wochen nach Symptombeginn augenärztlich vor, 350 (83%) innerhalb von vier Wochen. In dem Patientenkollektiv erhielten 49 (50%) der ZVV Patienten, 27 (48%) der VAV Patienten, 14 (33%) der ZAV Patienten, 27 (51%) der AAV Patienten und 38 (54%) Patienten mit der Diagnose einer AION bis zu vier Wochen zuvor eine Impfung gegen COVID-19. Die GHS-Daten ergaben ebenfalls kein erhöhtes Risiko eines retinalen Gefäßverschlusses innerhalb der ersten vier Wochen nach einer COVID-19-Impfung (OR=1.08; 95%-CI: 0.75-1.56, p=0.67). Es konnte unabhängig von Art des Gefäßverschlusses und Impfstoffes keine Häufung der Diagnosen im Zusammenhang mit einer Impfung gegen COVID-19 festgestellt werden. Schlussfolgerungen: Es besteht kein Hinweis auf ein erhöhtes Risiko für einen retinalen Gefäßverschluss im Anschluss an eine COVID-19 Impfung.Background: To investigate whether vaccination against SARS-CoV-2 is associated with the onset of retinal vascular occlusive disease (RVOD). Methods: In this multicentre study, data from patients with central and branch retinal vein occlusion (CRVO and BRVO), central and branch retinal artery occlusion (CRAO and BRAO), and anterior ischaemic optic neuropathy (AION) were retrospectively collected during a 2-month index period (1 June–31 July 2021) according to a defined protocol. The relation to any previous vaccination was documented for the consecutive case series. Numbers of RVOD and COVID-19 vaccination were investigated in a case-by-case analysis. A case–control study using age- and sex-matched controls from the general population (study participants from the Gutenberg Health Study) and an adjusted conditional logistic regression analysis was conducted. Results: Four hundred and twenty-one subjects presenting during the index period (61 days) were enrolled: one hundred and twenty-one patients with CRVO, seventy-five with BRVO, fifty-six with CRAO, sixty-five with BRAO, and one hundred and four with AION. Three hundred and thirty-two (78.9%) patients had been vaccinated before the onset of RVOD. The vaccines given were BNT162b2/BioNTech/Pfizer (n = 221), followed by ChadOx1/AstraZeneca (n = 57), mRNA- 1273/Moderna (n = 21), and Ad26.COV2.S/Johnson & Johnson (n = 11; unknown n = 22). Our case–control analysis integrating population-based data from the GHS yielded no evidence of an increased risk after COVID-19 vaccination (OR = 0.93; 95% CI: 0.60–1.45, p = 0.75) in connection with a vaccination within a 4-week window. Conclusions: To date, there has been no evidence of any association between SARS-CoV-2 vaccination and a higher RVOD risk.2025-05-0

Determination of the density of vitreous samples, ocriplasmin and various anti-VEGF substances to optimise postoperative position after intravitreal drug administration (IVOM)

Die Dissertation basiert auf der Idee, nach intravitrealer operativer Medikamentenapplikation (IVOM) in die Glaskörpermitte den Wirkstoff durch „dichtegerechte“ Lagerung in den prämakulären Bereich wandern zu lassen. Ziel ist die Steigerung der Wirkstoffkonzentration am Wirkort zur Therapieverbesserung der behandelten Grunderkrankung. Voraussetzung für diese Theorie sind Dichteunterschiede zwischen den intravitreal applizierten Medikamenten und dem Glaskörper. Im Rahmen der Studie wurde die Dichte von 99 Glaskörperproben, Ocriplasmin und der Anti-VEGF-Substanzen Lucentis®, Eylea® und Avastin® untersucht. Dabei wurden definierte Volumina der Proben auf ihre Masse hin geprüft und im Anschluss ihre Dichte berechnet. Es konnte gezeigt werden, dass es einen statistisch signifikanten Dichteunterschied zwischen den Glaskörperproben und den Anti-VEGF-Substanzen gibt, wobei die Dichte der Anti-VEGF-Substanzen größer war als die Glaskörperdichte. Der Dichteunterschied zwischen Ocriplasmin und den Glaskörperproben war statistisch nicht signifikant. Eine „dichtegerechte“ Lagerung sähe entsprechend eine Position des Patienten in Rückenlage nach Injektion der Anti-VEGF-Substanzen vor, sodass der Wirkstoff in Richtung des prämakulären Bereiches absinken kann. Für Ocriplasmin ist, bei nicht signifikantem Dichteunterschied zum Glaskörper, kein relevanter Einfluss auf die intravitreale Medikamentendistribution durch „dichtegerechte“ Lagerung zu erwarten. Die intravitreale Wirkstoffdistribution nach IVOM ist ein höchst komplexes Zusammenspiel aus Wirkstoffeigenschaften, Glaskörpereigenschaften, der genauen Art- und Weise der Applikation und intravitrealen Transportprozessen. Durch die Bestimmung der Glaskörper- und Medikamentendichte wurde ein Teilaspekt dieses Komplexes analysiert. Ob die Medikamentendistribution durch die „dichtegerechte“ Lagerung letztlich beeinflusst wird, kann durch die Studie nicht ausreichend beantwortet werden.The dissertation is based on the idea of allowing the drug to migrate into the premacular area through ‘density-appropriate’ patient positioning after intravitreal drug application (IVOM) in the centre of the vitreous body. The aim is to increase the drug concentration at the site of action and therefore improve the therapy of the underlying disease being treated. The prerequisite for this theory is a difference in density between the intravitreally applied drug and the vitreous body. As part of the study, the density of 99 vitreous samples, ocriplasmin and the anti-VEGF substances Lucentis®, Eylea® and Avastin® were analysed. Defined volumes of the samples were tested for their mass and their density was then calculated. It was shown that there was a statistically significant difference in density between the vitreous samples and the anti-VEGF substances, whereby the density of the anti-VEGF substances was greater than the vitreous density. The difference in density between ocriplasmin and the vitreous samples was not statistically significant. Accordingly, ‘density-appropriate’ positioning would involve the patient lying on their back after injection of the anti-VEGF substances so that the drug can sink towards the premacular area. For ocriplasmin no relevant influence on intravitreal drug distribution is to be expected from ‘density-appropriate’ positioning as there is no significant difference in density to the vitreous body. The intravitreal drug distribution after IVOM is a highly complex interplay of drug properties, vitreous body properties, the exact method of application and intravitreal transport processes. One partial aspect of this complex was analysed by determining the vitreous body and drug density. Whether drug distribution is ultimately influenced by ‘density-appropriate’ positioning cannot be adequately answered by the study.2025-04-1

Targeting SARS-CoV-2 with Nanobodies and Antibodies: Neutralization and Escape Variants

The SARS-CoV-2 pandemic revealed significant limitations in existing preventive measures against coronavirus infections. Before vaccines were approved, over 64 million infections and 1.6 million deaths were reported globally (World Health Organization, 2024), underscoring the need for rapid therapeutic interventions. We hypothesized that blocking the initial step of SARS-CoV-2 infection, i.e. the binding of the viral Spike protein to the human Angiotensin-Converting Enzyme 2 (ACE2) receptor, could neutralize infection. To disrupt this critical interaction, we made use of VHH antibodies (also called “nanobodies”), which are variable domains of heavy-chain-only antibodies. Nanobodies targeting the SARS-CoV-2 Spike protein are well suited for the viral neutralization due to their specificity and high-affinity. We demonstrated that nanobodies could be produced rapidly against multiple SARS-CoV-2 variants of concern, and that they were capable of potently neutralizing both authentic virus variants and vesicular stomatitis virus (VSV)-based pseudotyped viruses. Importantly, one representative nanobody exhibited potent neutralization of SARS-CoV-2 even in an aerosolized form and its inhalation provided near-complete protection to Syrian golden hamsters, either as a prophylactic treatment prior to infection or as a therapeutic agent administered 24 hours after infection. In summary, these findings highlight the potential of aerosolized nanobodies as a promising therapeutic or preventive strategy against SARS-CoV-2. While no nanobody-based therapeutic solutions for SARS-CoV-2 are currently clinically available, therapeutic monoclonal antibodies also targeting the viral Spike protein have played a critical role in mitigating disease severity, particularly in patients at high risk of hospitalization. However, as the pandemic progressed, the emergence of SARS-CoV-2 variants with Spike protein mutations posed significant challenges, most notably the reduced efficacy of vaccines and therapeutic antibodies. To make the occurrence of such mutations more predictable, we developed a method to efficiently identify antibody-resistant SARS-CoV-2 mutants by selecting them from mutagenized virus pools. Mutations were induced using N4-hydroxycytidine (NHC), the active compound of the antiviral drug molnupiravir, followed by virus passaging in the presence of antibodies. This approach enabled the identification of specific Spike mutations potentially associated with resistance. These mutations were subsequently validated through VSV-pseudotype assays and immunofluorescence analyses. Some of them, such as F490S, E484K, and K444R, were also detected in circulating variants, while others, e.g. D428G and K462E, were novel. Crucially, all identified mutations retained the ability of the virus to bind ACE2 and remain infectious, highlighting SARS-CoV-2’s remarkable adaptability to immune pressures. Thus, in the second study, we developed a strategy for predicting the therapeutic efficacy of antibodies against emerging SARS-CoV-2 variants.2025-05-2

Cortical PV and VIP neurons are necessary for texture discrimination performance of freely behaving mice

Rodents gather information about their surroundings through their whiskers, enabling them to differentiate textures, recognize objects, and navigate. Each whisker is represented in the barrel cortex (S1BF) by a single cortical column in an isomorphic manner. The microcircuits within each barrel-related column comprise both excitatory and inhibitory neurons. Extensive literature exists on genetically defined GABAergic neurons—parvalbumin (PV), vasoactive intestinal polypeptide (VIP), and somatostatin (SST)—and their involvement in tactile perception through whisking, including both passive stimulation of the whiskers and active touch. S1BF is well established as the core node for whisker-based texture discrimination. However, how PV, VIP, and SST interneurons contribute to the behavioral outcome of information processing during tactile perception in texture discrimination remains unclear. This study aims to further investigate the role of PV and VIP neurons in S1BF through chemogenetic activation in awake, freely behaving mice trained in a texture discrimination task. For this purpose, a novel whisker-based texture discrimination paradigm, the textured T-maze (TT), was developed, allowing mice to explore the maze freely while being trained on texture discrimination. PV-cre and VIP-cre mice exhibited comparable baseline performance. An activating Cre-dependent chemogenetic virus was bilaterally injected into the S1BF of PV-cre and VIP-cre mice to express “activating” DREADDs, enabling selective manipulation of PV and VIP cells via intraperitoneal administration of clozapine-N-oxide (CNO). Chemogenetic activation of either PV or VIP neurons impaired texture discrimination, reducing performance to chance level. Whole-cell patch-clamp experiments demonstrated that the intrinsic properties of transfected cells were comparable to those of non-transfected counterparts. The depolarizing effect of CNO on transfected cells was tested via bath application. Recordings confirmed that PV cells exhibited depolarization as expected from the viral construct, whereas VIP cells underwent depolarization block. In conclusion, although the chemogenetic virus did not produce equivalent depolarization effects in PV and VIP cells, the activation of PV cells or the putative deactivation of VIP cells in S1BF disrupted perceptual discrimination in freely behaving mice during the texture discrimination task.2025-04-0

The Effect of Erythropoietin on the Survival of Brain Neurons of Locusta migratoria after Damage by UV Radiation

Erythropoetin ist aufgrund seines anti-apoptotischen Potenzials ein vielversprechender Kandidat für Neuroprotektion. Ein limitierender Faktor in Studien sind bisher unter anderem thromboembolische Nebenwirkungen. Es wurden verschiedene Rezeptoren und Signalwege identifiziert, über die Erythropoetin und seine natürliche Splice-Variante EV-3 (teilweise selektiv) Zellprotektion vermitteln. Einer dieser Rezeptoren ist der bisher kaum charakterisierte CRLF3 Rezeptor. Das Erythropoetin/CRLF3 Signalsystem ist ein vermutlich phylogenetisch sehr altes, gut konserviertes und allgemein zellprotektives Signalsystem, das in dieser Studie an Hirnnervenzellen der L. migratoria näher untersucht wurde. Erythropoetin wirkt bei Hypoxie zuverlässig anti-apoptotisch. Wenige Studien an Säugetierzellen zeigen, dass Erythropoetin bei UV-geschädigten Zellen zellprotektiv wirken kann. Diese Arbeit hat das anti-apoptotische Potential des Epo/CRLF3 Signalsystems erstmals bei einer Schädigung durch UVC-Strahlung getestet. UVC-Strahlung induziert vor allem über eine DNA-Schädigung Apoptose, unterscheidet sich demnach grundlegend von einer Zellschädigung durch Hypoxie. Dadurch lassen sich potenzielle Anhaltspunkte zum Wirkmechanismus des Epo/CRLF3 Zellschutz gewinnen. Zudem wurde erstmalig die anti-apoptotische Wirkung AChE-Inhibitoren bei einer UVC- Schädigung untersucht. AChE-Inhibitoren wirken bei Insekten und Säugetieren über andere Mechanismen als Epo anti-apoptotisch, was bisher überwiegend im Zusammenhang mit Hypoxie-bedingten Zellschäden untersucht wurde. Die Experimente wurden an primären Nervenzellkulturen aus Gehirnen der Wanderheuschrecke L. migratoria durchgeführt. Nach Kultivierung, Behandlung mit rhEpo und AChE-Inhibitoren (NSB und TRB), anschließender Schädigung mit UVC-Strahlung wurden die Zellen erneut inkubiert (Post-Stimulus-Inkubationsdauer) und dann mit DAPI gefärbt. Abschließend wurde die Zellviabilität verblindet anhand der Zellkernmorphologie bestimmt. Weder Erythropoetin noch AChE-Inhibitoren hatten einen anti-apoptotischen oder zellprotektiven Effekt auf das Überleben der Zellen nach einer Zellschädigung durch UVC- Bestrahlung (p < 0,05). In den Experimenten mit Erythropoetin wurden sowohl lange (30 min) als auch kurze (3 und 5 min) UV-Bestrahlungszeiten getestet, sowie unterschiedlich lange Post-Stimulus-Inkubationszeiten (5 und 24 h). Bei allen Experimenten konnte kein anti-apoptotischer Effekt auf die Insektenneuronen gezeigt werden. Ob das Ausbleiben des protektiven Effekts an der DNA-schädigenden UVC-Bestrahlung, an der Zellart oder den intrazellulären Signalwegen welche durch CRLF3 angeschaltet werden liegt, bleibt bisher unbeantwortet und bedarf weiterer Untersuchungen.Erythropoietin (Epo) is a well-known candidate for neuroprotection due to its anti-apoptotic properties. One limiting factor in previous studies has been thromboembolic side effects. Various receptors and signaling pathways have been identified through which erythropoietin and its naturally occurring splice variant EV-3 (partially selectively) mediate cell protection. One of these receptors is the CRLF3 receptor, which has been scarcely characterized to date. The erythropoietin/CRLF3 signaling system is presumed to be a phylogenetically ancient, well-conserved, and broadly cytoprotective pathway, which was examined in this study using brain neurons of Locusta migratoria. Erythropoietin reliably exhibits anti-apoptotic effects under hypoxic conditions. A few studies in mammalian cells have shown that erythropoietin may also exert cytoprotective effects in UV-damaged cells. This study is the first to investigate the anti-apoptotic potential of the Epo/CRLF3 signaling system following damage induced by UVC radiation. Since UVC primarily induces apoptosis through DNA damage, this mechanism is fundamentally different from hypoxia-induced cellular damage. As such, the study may provide new insights into the underlying mechanisms of Epo/CRLF3-mediated cell protection. In addition, the anti-apoptotic effects of AChE inhibitors in the context of UVC-induced damage were investigated for the first time. In both insects and mammals, AChE inhibitors act via different mechanisms than erythropoietin, and their protective effects have so far been studied mostly in relation to hypoxia-induced cell damage. Experiments were conducted using primary neuronal cultures from the brains of L. migratoria. After culturing, cells were treated with recombinant human Epo (rhEpo) and AChE inhibitors (NSB and TRB), then exposed to UVC radiation. Following post-stimulus incubation, the cells were stained with DAPI, and cell viability was assessed in a blinded manner based on nuclear morphology. Neither erythropoietin nor the AChE inhibitors showed anti-apoptotic or cytoprotective effects on cell survival after UVC-induced damage (p < 0.05). In the erythropoietin experiments, both long (30 min) and short (3 and 5 min) UVC exposure durations, as well as different post-stimulus incubation times (5 and 24 hours), were tested. None of these conditions revealed an anti-apoptotic effect on insect neurons. Whether the absence of a protective effect is due to the DNA-damaging nature of UVC exposure, the specific cell type, or the intracellular signaling pathways activated by CRLF3 remains unclear and requires further investigation.2025-06-0

In vitro performance of six combinations of adjustable differential pressure valves and fixed anti siphon devices with and without vertical motion

Shunt therapy using adjustable differential pressure valves combined with anti-siphon devices (ASDs) is a well-established approach for treating normal pressure hydrocephalus but continues to pose risks of severe complications, such as overdrainage. This study is aimed to analyze the flow characteristics of 3 commercial differential pressure valves paired with 2 different ASDs under static and dynamic conditions. The differential pressure valves proGAV 2.0 [PG], CertasPlus [CP], and HakimMedos [HM] were evaluated in combination with the gravity-regulated ASD (ShuntAssistant [SA]) and the flow-regulated ASD (SiphonGuard [SG]. Flow data was recorded at differential pressures ranging from 4 to 40 cmH₂O in both stationary setups and during vertical oscillations at frequencies of 2, 3, and 4 Hz. Additionally, the impact of inclination angles (90° vs. 60°) on flow rates was assessed. Results demonstrated that combinations with the gravity-regulated ASD allowed no or minimal flow at low differential pressures in static conditions, while a linear increase in flow occurred at higher pressures. Dynamic testing revealed significant flow increases for these combinations, proportional to oscillation frequency. In contrast, combinations with flow-regulated ASDs exhibited lower flow rates overall, and movement did not increase flow. Instead, the characteristic biphasic flow curve observed under static conditions was eliminated during motion. The distinct flow characteristics of the ASDs highlight the critical importance of selecting appropriate valve combinations for clinical applications. The findings provide valuable insights into tailoring shunt systems to individual patient needs and mitigating complications associated with movement. Further studies should build upon these results to optimize shunt systems and reduce the incidence of overdrainage in clinical practice.2025-02-1