JZJulian Zimmermann

Julian Zimmermann

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Previous Organizations / Institutes

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Julian Zimmermann has a total of 386 co-authors. Here are the top co-authors by number of shared publications:


Latest Publications

  • Factors Associated With Relapse in Patients With Neurosarcoidosis

    by Louisa Nitsch, Dirk Skowasch, Edouard Courtin, Pierre Duffau, Carolin Otto, Klemens Ruprecht, Christine Dambietz, Michael Heming, Gerd Meyer zu Hörste, Keld-Erik Byg, et al.

    Five to 10 percent of patients with sarcoidosis show involvement of the nervous system. Given the serious nature of neurosarcoidosis and the high risk of irreversible neurologic damage, rapid diagnosis, accurate prognostication, and individualized treatment are crucial. The aim of this study was to identify factors associated with relapses in neurosarcoidosis. In this multicenter retrospective cohort study, patients diagnosed with possible, probable, or definite neurosarcoidosis between January 1, 2010, and June 30, 2024, at 6 tertiary neuroimmunology centers across Europe were included. Patients were identified from the respective hospital-based databases by the participating centers. Clinical presentation, imaging results, CSF analysis, and immunosuppressive therapies were evaluated. Predictors of relapse, defined as clinical relapse or progression, or new MRI lesions on follow-up ≥2 months after initial manifestation, were analyzed with log-rank tests and Cox regression models, and therapeutic strategies in clinical practice were assessed. The association between identified risk factors (RFs) and therapeutic strategies was explored. A total of 174 patients with neurosarcoidosis were included with a median follow-up of 24 months (interquartile range 12-48.8). The mean age was 48.1 years, and 57.5% were female. CNS parenchymal lesions including encephalitis, myelitis, and optic neuritis (hazard ratio [HR] 2.3, 95% CI 1.3-4.2); CSF-specific oligoclonal bands (OCBs) (HR 2.1, 95% CI 1.3-3.6); CSF glucose p < 0.01). The likelihood of treatment escalation increased with the number of RFs, from 14.3% in patients without RFs to 28.2% and 50% in patients with 1-2 or 3-4 RFs, respectively (p < 0.01). The identification of specific RFs, including parenchymal lesions, OCBs, CSF glucose <40 mg/dL, and CSF protein ≥1,000 mg/dL, enables better prognostication and might inform individualized treatment approaches. Patients with multiple RFs are at greater risk of relapse, possibly suggesting the need for more aggressive therapies.


  • Endovascular treatment of cerebral sinus thrombosis due to vaccine-induced immune thrombotic thrombocytopenia

    by Johannes Weller, Katarzyna Krzywicka, Anita van de Munckhof, Franziska Dorn, Katharina Althaus, Felix J Bode, Monica Bandettini di Poggio, Brian Buck, Timothy Kleinig, Charlotte Cordonnier, et al.

    Introduction: There is little data on the role of endovascular treatment (EVT) of cerebral venous sinus thrombosis (CVST) due to vaccine-induced immune thrombotic thrombocytopenia (VITT). Here, we describe clinical characteristics and outcomes of CVST-VITT patients who were treated with EVT. Patients and methods: We report data from an international registry of patients who developed CVST within 28 days of SARS-CoV-2 vaccination, reported between 29 March 2021 and 6 March 2023. VITT was defined according to the Pavord criteria. Results: EVT was performed in 18/136 (13%) patients with CVST-VITT (92% aspiration and/or stent retrieval, 8% local thrombolysis). Most common indications were extensive thrombosis and clinical or radiological deterioration. Compared to non-EVT patients, those receiving EVT had a higher median thrombus load (4.5 vs 3). Following EVT, local blood flow was improved in 83% (10/12, 95% confidence interval [CI] 54–96). One (6%) asymptomatic sinus perforation occurred. Eight (44%) patients treated with EVT also underwent decompressive surgery. Mortality was 50% (9/18, 95% CI 29–71) and 88% (8/9, 95% CI 25–66) of surviving EVT patients achieved functional independence with a modified Rankin Scale score of 0–2 at follow-up. In multivariable analysis, EVT was not associated with increased mortality (adjusted odds ratio, 0.66, 95% CI 0.16–2.58). Discussion and conclusion: We describe the largest cohort of CVST-VITT patients receiving EVT. Half of the patients receiving EVT died during hospital admission, but most survivors achieved functional independence.


  • Open Access

    Additive prognostic impact of the cerebrospinal fluid arginine/ornithine ratio to established clinical scores in aneurysmal subarachnoid hemorrhage

    by Johannes Weller, Tim Lampmann, Harun Asoglu, Matthias Schneider, Stefan Felix Ehrentraut, Felix Lehmann, Erdem Güresir, Franziska Dorn, Gabor C. Petzold, Hartmut Vatter, et al.

    Cerebrospinal fluid (CSF) metabolites are increasingly recognized as prognostic factors in aneurysmal subarachnoid hemorrhage (SAH). The CSF arginine/ornithine ratio (Arg/Orn) was shown to predict cerebral vasospasms and clinical outcome in SAH. The additive prognostic value of Arg/Orn over established prognostic scores has not been investigated. CSF Arg/Orn and the established prognostic scores SAH, FRESH, SAH-PDS, HAIR, Rosen–McDonald, Hunt and Hess, WFNS and modified Fisher scale were determined in a prospective cohort of patients with aneurysmal SAH. Logistic regression models to predict a favorable outcome, defined as a modified Rankin Scale score of 0–3 at 3 months follow-up, were constructed for each score, both with and without the addition of Arg/Orn. The impact of Arg/Orn was assessed comparing logistic regression models containing the respective score with and without Arg/Orn with the likelihood ratio chi-squared test. CSF Arg/Orn and clinical scores were determined in 38 SAH patients. Arg/Orn was an independent predictor of clinical outcome when added to established prognostic scores (p < 0.05) with the exception of HAIR (p = 0.078). All models were significantly improved if Arg/Orn was added as a covariable (p < 0.05). The results of this study confirm Arg/Orn as an independent prognostic factor and its addition improves established prognostic models in SAH.


  • Open Access

    The Diagnostic Value of Cerebrospinal Fluid Lactate for Detection of Sepsis in Community-Acquired Bacterial Meningitis

    by Louisa Nitsch, Stefan Felix Ehrentraut, Marcus Grobe-Einsler, Felix J. Bode, Mohammed Banat, Matthias Schneider, Felix Lehmann, Julian Zimmermann, Johannes Weller

    Community-acquired bacterial meningitis conveys significant morbidity and mortality due to intracranial and systemic complications, and sepsis is a major contributor to the latter. While cerebrospinal fluid (CSF) analysis is essential in the diagnosis of bacterial meningitis, its predictive utility for detection of sepsis is unknown. We investigated the diagnostic performance of CSF parameters for sepsis defined by the Sepsis-3 criteria in a retrospective cohort of patients with community-acquired bacterial meningitis. Among 103 patients, 69.5% developed sepsis. CSF lactate was associated with sepsis with an odds ratio of 1.11 (p = 0.022), while CSF cell counts, glucose and protein levels were not (all p > 0.4). Employing the optimal cutoff of 8.2 mmol/L, elevated CSF lactate resulted in a sensitivity of 81.5% and specificity of 61.5% for sepsis. In exploratory analyses, CSF lactate was also associated with in-hospital mortality with an odds ratio of 1.21 (p = 0.011). Elevated CSF lactate might contribute to early diagnosis of sepsis as well as prognostication in patients with community-acquired bacterial meningitis.


  • Open Access

    Parameters Associated with the Required Drug Dose of Intravenous Immunoglobulin in Stable Chronic Inflammatory Demyelinating Polyradiculoneuropathy

    by Ludger Feyen, Christina Schaub, Julian Zimmermann, Louisa Nitsch

    Background: Intravenous immunoglobulin (IVIg) is efficient and one of very few treatment options for patients with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP). However, finding the optimal dose of IVIg for individual CIDP patients remains challenging. The dose of IVIg needs to be adjusted individually. Considering the high healthcare costs of IVIg therapy, the overtreatment of some patients seen in placebo studies and the shortage of IVIg we recently experienced, as well as identifying factors associated with the required dose of IVIg in maintenance treatment, is extremely important. Thus, in this retrospective study, we analyze characteristics of patients with stable CIDP, which are associated with the required drug dose. Methods: 32 patients with stable CIDP treated with IVIg between July 2021 and July 2022 were identified from our database and included in this retrospective study. Patients’ characteristics were registered, and parameters were identified that were associated with the IVIg dose. Results: Age, cerebrospinal fluid protein elevation, disease duration, delay between symptom onset/diagnosis, Inflammatory Neuropathy Cause and Treatment (INCAT) score, and Medical Research Council Sum Score (MRC SS) were significantly associated with the required drug dose. In addition, an association of age, sex, elevated CSF protein, time interval between symptom onset and diagnosis, and the MRC SS with the required IVIg dose could be demonstrated in the multivariable regression analysis. Conclusions: Our model, which is based on routine parameters that are simple to address in the clinical practice, can be useful in adjusting the IVIg dose in patients with stable CIDP.


  • Open Access

    IL-17A Facilitates Entry of Autoreactive T-Cells and Granulocytes into the CNS During EAE

    by Julian Zimmermann, Louisa Nitsch, Marius Krauthausen, Marcus Müller

    Interleukin-17A plays a crucial role in multiple sclerosis and other autoimmune diseases. Although the link between IL-17 and disease activity has been clearly demonstrated, the precise function of this cytokine remains elusive. Here, we investigated the function of astrocyte-targeted IL-17A production in GF/IL-17 transgenic mice during EAE. In particular, IL-17A is important during disease induction. In mice with transgenic IL-17A production, disease occurs earlier and peak disease is more severe, whereas remission is unimpaired. IL-17A synthesis is associated with increased infiltration of granulocytes into the CNS and microglial activation. Moreover, IL-17A synthesis allows induction of MOG-EAE without the additional administration of the co-adjuvant pertussis toxin. Examination of double transgenic GF/IL-17 2D2 mice revealed that, in addition, local IL-17A production facilitates spontaneous infiltration of immune cells into the CNS in mice expressing a MOG-specific T-cell receptor. Overall, we provide evidence for a crucial effect of IL-17A in the induction phase of EAE, facilitating the infiltration of granulocytes and autoreactive T-cells into the CNS.


  • Open Access

    IL-17A facilitates entry of autoreactive T-cells and granulocytes into the CNS during EAE

    by Julian Zimmermann, Louisa Nitsch, Marius Krauthausen, Marcus Müller

    Interleukin-17A plays a crucial role in multiple sclerosis and other autoimmune diseases. Although the link between IL-17 and disease activity has been clearly demonstrated, the precise function of this cytokine remains elusive. Here, we investigated the function of astrocyte targeted IL-17A production in GF/IL17 transgenic mice during EAE. In particular, IL-17A is importantduring disease induction. In mice with transgenic IL-17A production, disease occurs earlier and peak disease is more severe, whereas remission is unimpaired. IL-17A synthesis is associated with increased infiltration of granulocytes into the CNS and microglial activation. Moreover, IL-17A synthesis allows induction of MOG-EAE without the additional administration of the co-adjuvant pertussis toxin. Examination of double transgenic GF/IL17 2D2 mice revealed that, in addition, local IL-17A production facilitates spontaneous infiltration of immune cells into the CNS in mice expressing a MOG-specific T-cell receptor. Overall, we provide evidence for a crucial effect of IL-17A in the induction phase of EAE, facilitating the infiltration of granulocytes and autoreactive T cells into the CNS.

  • Open Access

    Immune Modifying Effect of Drug Free Biodegradable Nanoparticles on Disease Course of Experimental Autoimmune Neuritis

    by Ehsan Elahi, Mohamed Ehab Ali, Julian Zimmermann, Daniel R. Getts, Marcus Müller, Alf Lamprecht

    Guillain-Barré Syndrome (GBS) is an autoimmune disease of demyelination and inflammation of peripheral nerves. Current treatments are limited to plasma exchange and intravenous immunoglobulins. Cargo-free nanoparticles (NPs) have been evaluated here for their therapeutic benefit on the disease course of experimental autoimmune neuritis (EAN), mimicking the human GBS. NPs prepared from poly-lactic co-glycolic acid (PLGA) with variable size and surface charge (i.e., 500 nm vs. 130 nm, polyvinyl alcohol (PVA) vs. sodium cholate), were intravenously administered in before- or early-onset treatment schedules in a rat EAN model. NP treatment mitigated distinctly the clinical severity of EAN as compared to the P2-peptide control group (P2) in all treatments and reduced the trafficking of inflammatory monocytes at inflammatory loci and diverted them towards the spleen. Therapeutic treatment with NPs reduced the expression of proinflammatory markers (CD68 (P2: 34.8 ± 6.6 vs. NP: 11.9 ± 2.3), IL-1β (P2: 18.3 ± 0.8 vs. NP: 5.8 ± 2.2), TNF-α (P2: 23.5 ± 3.7 vs. NP: 8.3 ± 1.7) and elevated the expression levels of anti-inflammatory markers CD163 (P2: 19.7 ± 3.0 vs. NP: 41.1 ± 6.5; all for NP-PVA of 130 nm; relative to healthy control). These results highlight the therapeutic potential of such cargo-free NPs in treating EAN, which would be easily translatable into clinical use due to their well-known low-toxicity profile.


  • Outcomes of Cerebral Venous Thrombosis due to Vaccine-Induced Immune Thrombotic Thrombocytopenia After the Acute Phase

    by Anita van de Munckhof, Erik Lindgren, Timothy J. Kleinig, Thalia S. Field, Charlotte Cordonnier, Katarzyna Krzywicka, Sven Poli, Mayte Sánchez van Kammen, Afshin Borhani-Haghighi, Robin Lemmens, et al.

    Background: Cerebral venous thrombosis (CVT) due to vaccine-induced immune thrombotic thrombocytopenia (VITT) is a severe condition, with high in-hospital mortality rates. Here, we report clinical outcomes of patients with CVT-VITT after SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) vaccination who survived initial hospitalization. Methods: We used data from an international registry of patients who developed CVT within 28 days of SARS-CoV-2 vaccination, collected until February 10, 2022. VITT diagnosis was classified based on the Pavord criteria. Outcomes were mortality, functional independence (modified Rankin Scale score 0–2), VITT relapse, new thrombosis, and bleeding events (all after discharge from initial hospitalization). Results: Of 107 CVT-VITT cases, 43 (40%) died during initial hospitalization. Of the remaining 64 patients, follow-up data were available for 60 (94%) patients (37 definite VITT, 9 probable VITT, and 14 possible VITT). Median age was 40 years and 45/60 (75%) patients were women. Median follow-up time was 150 days (interquartile range, 94–194). Two patients died during follow-up (3% [95% CI, 1%–11%). Functional independence was achieved by 53/60 (88% [95% CI, 78%–94%]) patients. No new venous or arterial thrombotic events were reported. One patient developed a major bleeding during follow-up (fatal intracerebral bleed). Conclusions: In contrast to the high mortality of CVT-VITT in the acute phase, mortality among patients who survived the initial hospitalization was low, new thrombotic events did not occur, and bleeding events were rare. Approximately 9 out of 10 CVT-VITT patients who survived the acute phase were functionally independent at follow-up.


  • Open Access

    Treatment-Limiting Decisions in Patients with Spontaneous Intracerebral Hemorrhage

    by Felix Lehmann, Matthias Schneider, Joshua D. Bernstock, Christian Bode, Valeri Borger, Stefan Felix Ehrentraut, Florian Gessler, Anna-Laura Potthoff, Christian Putensen, Lorena M. Schenk, et al.

    Background and Objectives: Treatment-limiting decisions (TLDs) are employed to actively withhold treatment/invasive interventions from patients in whom clinicians feel they would derive little to no benefit and/or suffer detrimental effects. Data regarding the employment of TLDs in patients with spontaneous intracerebral hemorrhage (ICH) remain sparse. Accordingly, this study sought to investigate both the prevalence of TLDs and factors driving TLDs in patients suffering from spontaneous ICH. Materials and Methods: This was a retrospective study of 249 consecutive patients with ICH treated from 2018–2019 at the Neurovascular Center of the University Hospital Bonn. Reasons deemed critical in the decision-making process with regard to TLD were ultimately extracted/examined via chart review of qualifying patients. Results: A total of 249 patients with ICH were included within the final analyses. During the time period examined, 49 patients (20%) had advanced directives in place, whereas in 53 patients (21%) consultation with relatives or acquaintances was employed before further treatment decisions. Overall, TLD ultimately manifested in 104 patients (42%). TLD was reached within 6 h after admission in 52 patients (50%). Congruent with severity of injury and expected outcomes, TLDs were more likely in patients with signs of cerebral herniation and an ICH score > 3 (p < 0.001). Conclusions: The present study examines details associated with TLDs in patients with spontaneous ICH. These data provide insight into key decisional processes and reinforce the need for further structured investigations in an effort to help guide patients and their families.