Universität des Saarlandes
  • Saarbrücken, Saarland, Germany
Recent publications
Background Aneurysmal subarachnoid hemorrhage (aSAH) is a severe event often complicated by cerebral vasospasm (CV). This study aimed to assess the efficacy and safety of clazosentan, an endothelin receptor antagonist, in reducing CV, delayed cerebral ischemia (DCI), and the need for rescue therapy in aSAH patients, while evaluating its impact on functional outcomes and mortality. Methods We conducted a literature search across multiple databases to identify relevant studies evaluating the effects of clazosentan in aSAH patients. Both cohort studies and randomized controlled trials (RCTs) were included. The primary outcomes were vasospasm incidence, moderate to severe vasospasm, DCI, and the need for rescue therapy. Secondary outcomes included functional outcomes, mortality, and adverse events. The data were pooled as Risk ratios (R/R) with 95 % confidence intervals (CI) using RevMan 5.4 software. Results A total of 11 studies, including 10 published and one unpublished, comprising 8,469 patients were included in the meta-analysis. Clazosentan significantly reduced the incidence of vasospasm (R/R = 0.49: 0.34–0.70), moderate to severe vasospasm (R/R = 0.53: 0.46–0.61), DCI (R/R = 0.70: 0.59–0.82), and the need for rescue therapy (R/R = 0.65: 0.52–0.83) compared to placebo. However, no significant improvement in functional outcomes or mortality rates was observed. Clazosentan was associated with increased rates of pulmonary adverse events (R/R = 1.89: 1.64–2.18), hypotension (R/R = 2.47: 1.79–3.42), and anemia (R/R = 1.49: 1.23–1.79) but no increased risk of hepatobiliary adverse events or cerebral hemorrhage. Conclusions Clazosentan demonstrates efficacy in reducing vasospasm, moderate to severe vasospasm, DCI, and the need for rescue therapy in aSAH patients, but does not significantly improve functional outcomes or mortality rates. While associated with specific adverse events, clazosentan may be a valuable adjunctive therapy in the management of aSAH, particularly in a high-risk population for vasospasm.
  • Vida Mashayekhi
    Vida Mashayekhi
  • Annika Schomisch
    Annika Schomisch
  • Sari Rasheed
    Sari Rasheed
  • [...]
  • Alexandra K. Kiemer
    Alexandra K. Kiemer
Background Tumor cells release extracellular vesicles (EVs) that contribute to the polarization of macrophages towards tumor-associated macrophages (TAMs). High expression levels of the RNA binding protein IGF2BP2/IMP2 are correlated with increased tumor cell proliferation, invasion, and poor prognosis in the clinic. However, there is a lack of understanding of whether IMP2 affects the cargo of cancer cell-derived EVs, thereby modulating macrophage polarization. Methods EVs were isolated from IMP2-expressing HCT116 parental cells (WT) and CRISPR/Cas9 IMP2 knockout (KO) cells. EVs were characterized according to MISEV guidelines, microRNA cargo was assessed by microRNA-Seq, and the protein cargo was analyzed by proteomics. Primary human monocyte-derived macrophages (HMDMs) were polarized by EVs, and the expression of genes and surface markers was assessed using qPCR and flow cytometry, respectively. Morphological changes of macrophages, as well as the migratory potential of cancer cells, were assessed by the Incucyte ® system and macrophage matrix degradation potential by zymography. Changes in the metabolic activity of macrophages were quantified using a Seahorse ® analyzer. For in vivo studies, EVs were injected into the yolk sac of zebrafish larvae, and macrophages were isolated by fluorescence-activated cell sorting. Results EVs from WT and KO cells had a similar size and concentration and were positive for 25 vesicle markers. The expression of tumor-promoting genes was higher in macrophages polarized with WT EVs than KO EVs, while the expression of TNF and IL6 was reduced. A similar pattern was observed in macrophages from zebrafish larvae treated in vivo. WT EV-polarized macrophages showed a higher abundance of TAM-like surface markers, higher matrix degrading activity, as well as a higher promotion of cancer cell migration. MicroRNA-Seq revealed a significant difference in the microRNA composition of WT and KO EVs, particularly a high abundance of miR-181a-5p in WT EVs, which was absent in KO EVs. Inhibitors of macropinocytosis and phagocytosis antagonized the delivery of miR-181a-5p into macrophages and the downregulation of the miR-181a-5p target DUSP6 . Proteomics data showed differences in protein cargo in KO vs . WT EVs, with the differentially abundant proteins mainly involved in metabolic pathways. WT EV-treated macrophages exhibited a higher basal oxygen consumption rate and a lower extracellular acidification rate than KO EV-treated cells. Conclusion Our results show that IMP2 determines the cargo of EVs released by cancer cells, thereby modulating the EVs' actions on macrophages. Expression of IMP2 is linked to the secretion of EVs that polarize macrophages towards a tumor-promoting phenotype.
We present and benchmark a quantum computing approach to calculate the two-dimensional coherent spectrum (2DCS) of high-spin models. Our approach is based on simulating their real-time dynamics in the presence of several magnetic field pulses, which are spaced in time. We utilize the adaptive variational quantum dynamics simulation algorithm for the study due to its compact circuits, which enables simulations over sufficiently long times to achieve the required resolution in frequency space. Specifically, we consider an antiferromagnetic quantum spin model that incorporates Dzyaloshinskii-Moriya interactions and single-ion anisotropy. The obtained 2DCS spectra exhibit distinct peaks at multiples of the magnon frequency, arising from transitions between different eigenstates of the unperturbed Hamiltonian. By comparing the one-dimensional coherent spectrum with 2DCS, we demonstrate that 2DCS provides a higher resolution of the energy spectrum. We further investigate how the quantum resources scale with the magnitude of the spin using two different binary encodings of the high-spin operators: the standard binary encoding and the Gray code. At low magnetic fields both encodings require comparable quantum resources, but at larger field strengths the Gray code is advantageous. Numerical simulations for spin models with increasing number of sites indicate a polynomial system-size scaling for quantum resources. Lastly, we compare the numerical 2DCS with experimental results on a rare-earth orthoferrite system. The observed strength of the magnonic high-harmonic generation signals in the 2DCS of the quantum high-spin model aligns well with the experimental data, showing significant improvement over the corresponding mean-field results.
Aging leads to various alterations in immune cell functions. Here, we report our surprising findings that despite immunosenescence, CD8+ T cells’ cytotoxic efficiency increases with age. The FRET-based apoptosis sensor pCasper, stably transfected into tumor cells, revealed fundamental changes in the cytotoxic mechanisms. Antigen-specific CD8+ T cells from elderly OT-I mice shift from apoptotic to necrotic killers. This capability might affect cell-based immunotherapies in old age.
Mitochondria form extensive networks that rapidly adapt to cellular demands. The formation and disassembly of these structures result from a balance between fission and fusion of the two mitochondrial membranes that are decisively controlled by Dynamin-like GTPases such as OPA1. This protein forms oligomers which mediate the fusion of the inner mitochondrial membrane by a unique mechanism that involves the generation of curvature and the extraction of cardiolipin from the lipid bilayer.
Background Outcome of children with medulloblastoma (MB) and Fanconi Anemia (FA), an inherited DNA repair deficiency, has not been described systematically. Treatment is complicated by high vulnerability to treatment-associated side effects, yet structured data are lacking. This study aims at giving a comprehensive overview about clinical and molecular characteristics of pediatric FA MB patients. Methods Clinical data including detailed information on treatment and toxicities of six previously unreported FA MB patients were supplemented with data of 16 published cases. Results We identified 22 cases of children with FA and MB with clinical data available. All MBs with subgroup reporting were SHH-activated (n=9), confirmed by methylation profiling in five patients. FA MB patients exclusively belonged to complementation groups FA-D1 (n=16) or FA-N (n=3). Patients were treated with postoperative chemotherapy only (50%) or radiotherapy (RT)±chemotherapy (27%). 23% did not receive adjuvant therapy. Excessive treatment-related toxicities were frequent. Severe hematological toxicity occurred in 91% of patients treated with alkylating chemotherapy, while non-alkylating agents and RT were less toxic. Median overall survival (OS) was 1 year (95%CI 0.3-1.8). 1-year-progression-free-survival (PFS) was 26.3±10.1% and 1-year-OS was 42.1±11.3%. Adjuvant therapy prolonged survival (1y-OS/1y-PFS 0%/0% without adjuvant therapy vs. 53.3±12.9%/33.3±12.2% with adjuvant therapy, p=0.006/p=0.086). Conclusions MB in FA patients is strongly associated with SHH activation and FA-D1/FA-N. Despite the dismal prognosis, adjuvant therapy may prolong survival. Non-alkylating chemotherapy and RT are feasible in selected patients with careful monitoring of toxicities and dose adjustments. Curative therapy for FA MB-SHH remains an unmet medical need.
Single crystals of CaAl2Pt2, Ca2Al3Pt and Ca2AlPt2 were initially observed in an attempt to synthesize Ca3Al4Pt4. Their structures were determined using single‐crystal X‐ray diffraction experiments. While nominal CaAl2Pt2 (CaBe2Ge2 type, P4/nmm, a = 426.79(2), c = 988.79(6) pm, wR2 = 0.0679, 246 F2 values and 18 variables) and Ca2Al3Pt (Mg2Cu3Si type, P63/mmc, a = 561.46(5), c = 876.94(8) pm, wR2 = 0.0664, 214 F2 values and 13 variables) exhibit Al/Pt mixing, for Ca2AlPt2 (Ca2Ir2Si type, C2/c, a = 981.03(2) b = 573.74(1), c = 772.95(2) pm, β = 101.862(1)° wR2 = 0.0307, 2246 F2 values and 25 variables) no mixing was observed. Subsequently, the nominal compositions were targeted with synthetic attempts from the elements using arc‐melting and annealing techniques. For CaAl2Pt2 and Ca2Al3Pt always multi‐phase mixtures were observed while Ca2AlPt2 could be obtained as almost X‐ray pure material. Quantum‐chemical calculations were used to investigate the charge transfer in these compounds rendering them polar intermetallics with a designated [AlxPty]δ– polyanion and Caδ+ cations in the cavities of the polyanions.
Chip formation is considered one important indicator to evaluate machining processes. In particular, geometric features of chips may provide important insights for the assessment of machining stability and productivity. In fixed-abrasive machining processes, such as grinding and honing, chips are simultaneously produced by many of the geometrically undefined cutting edges. Despite being “undefined,” geometric features of abrasive grains can still be statistically characterized or described. Accordingly, it can be assumed that, under stable machining conditions, the geometric features of abrasive chips may also conform to certain statistical patterns. However, statistical characterization of abrasive chips can be very challenging due to their large quantity, irregular shapes, minuscule size, and sometimes tangled condition. In this study, an analysis method combining metallographic preparation and micro-computed tomography (micro-CT) has been developed to characterize abrasive chips produced by a honing stone. The results regarding the geometric characteristics of the obtained massive abrasive chips, i.e., their sizes and shapes, were presented and statistically described. It was found most chips had a size around 50 µm and the shape being a slightly elongated and curved cone. Most of the geometric features could meet a positive skewness distribution.
Microfluidics plays a pivotal role in organ‐on‐chip technologies and in the study of synthetic cells, especially in the development and analysis of artificial cell models. However, approaches that use synthetic cells as integral functional components for microfluidic systems to shape the microenvironment of natural living cells cultured on‐chip are not explored. Here, colloidosome‐based synthetic cells are integrated into 3D microfluidic devices, pioneering the concept of synthetic cell‐based microenvironments for organs‐on‐chip. Methods are devised to create dense and stable networks of silica colloidosomes, enveloped by supported lipid bilayers, within microfluidic channels. These networks promote receptor‐ligand interactions with on‐chip cultured cells. Furthermore, a technique is introduced for the controlled release of growth factors from the synthetic cells into the channels, using a calcium alginate‐based hydrogel formation within the colloidosomes. To demonstrate the potential of the technology, a modular plug‐and‐play lymph‐node‐on‐a‐chip prototype that guides the expansion of primary human T cells by stimulating receptor ligands on the T cells and modulating their cytokine environment is presented. This integration of synthetic cells into microfluidic systems offers a new direction for organ‐on‐chip technologies and suggests further avenues for exploration in potential therapeutic applications.
Gut bacteria regulate brain pathology of Alzheimer’s disease (AD) patients and animal models; however, the underlying mechanism remains unclear. In this study, 3-month-old APP-transgenic female mice with and without knock-out of Il-17a gene were treated with antibiotics-supplemented or normal drinking water for 2 months. The antibiotic treatment eradicated almost all intestinal bacteria, which led to a reduction in Il-17a-expressing CD4-positive T lymphocytes in the spleen and gut, and to a decrease in bacterial DNA in brain tissue. Depletion of gut bacteria inhibited inflammatory activation in both brain tissue and microglia, lowered cerebral Aβ levels, and promoted transcription of Arc gene in the brain of APP-transgenic mice, all of which effects were abolished by deficiency of Il-17a. As possible mechanisms regulating Aβ pathology, depletion of gut bacteria inhibited β-secretase activity and increased the expression of Abcb1 and Lrp1 in the brain or at the blood-brain barrier, which were also reversed by the absence of Il-17a. Interestingly, a crossbreeding experiment between APP-transgenic mice and Il-17a knockout mice further showed that deficiency of Il-17a had already increased Abcb1 and Lrp1 expression at the blood-brain barrier. Thus, depletion of gut bacteria attenuates inflammatory activation and amyloid pathology in APP-transgenic mice via Il-17a-involved signaling pathways. Our study contributes to a better understanding of the gut-brain axis in AD pathophysiology and highlights the therapeutic potential of Il-17a inhibition or specific depletion of gut bacteria that stimulate the development of Il-17a-expressing T cells.
Target values for arterial carbon dioxide tension (PaCO 2 ) in extracorporeal membrane oxygenation (ECMO) for acute respiratory distress syndrome (ARDS) are unknown. We hypothesized that lower PaCO 2 values on ECMO would be associated with lighter sedation. We used data from two independent patient cohorts with ARDS spending 1,177 days (discovery cohort, 69 patients) and 516 days (validation cohort, 70 patients) on ECMO and evaluated the associations between daily PaCO 2 , pH, and bicarbonate (HCO 3 ) with sedation. Median PaCO 2 was 41 (interquartile range [IQR] = 37–46) mm Hg and 41 (IQR = 37–45) mm Hg in the discovery and the validation cohort, respectively. Lower PaCO 2 and higher pH but not bicarbonate (HCO 3 ) served as significant predictors for reaching a Richmond Agitation Sedation Scale (RASS) target range of −2 to +1 (lightly sedated to restless). After multivariable adjustment for mortality, tracheostomy, prone positioning, vasoactive inotropic score, Simplified Acute Physiology Score (SAPS) II or Sequential Organ Failure Assessment (SOFA) Score and day on ECMO, only PaCO 2 remained significantly associated with the RASS target range (adjusted odds ratio 1.1 [95% confidence interval (CI) = 1.01–1.21], p = 0.032 and 1.29 [95% CI = 1.1–1.51], p = 0.001 per mm Hg decrease in PaCO 2 for the discovery and the validation cohort, respectively). A PaCO 2 ≤40 mm Hg, as determined by the concordance probability method, was associated with a significantly increased probability of a sedation level within the RASS target range in both patient cohorts (adjusted odds ratio = 2.92 [95% CI = 1.17–7.24], p = 0.021 and 6.82 [95% CI = 1.50–31.0], p = 0.013 for the discovery and the validation cohort, respectively).
Hepatocellular carcinoma (HCC) is the most frequent type of primary liver cancer and the third leading cause for cancer‐related death worldwide. The tumor is difficult‐to‐treat due to its inherent resistance to chemotherapy. Antistromal therapy is a novel therapeutic approach, targeting cancer‐associated fibroblasts (CAF) in the tumor microenvironment. CAF‐derived microfibrillar‐associated protein 5 (MFAP‐5) is identified as a novel target for antistromal therapy of HCC with high translational relevance. Biocompatible polypept(o)ide‐based polyion complex micelles (PICMs) constructed with a triblock copolymer composed of a cationic poly( l‐ lysine) complexing anti‐MFAP‐5 siRNA (siMFAP‐5) via electrostatic interaction, a poly(γ‐benzyl‐ l‐ glutamate) block loading cationic amphiphilic drug desloratatine (DES) via π−π interaction as endosomal escape enhancer and polysarcosine originated from amino acid sarcosine (N‐methylglycine) for protein‐repulsive effect, are generated for siRNA delivery. Intravenous injection of siMFAP‐5/DES PICMs significantly reduced the hepatic tumor burden in a syngeneic implantation model of HCC, with a superior MFAP‐5 knockdown effect over siMFAP‐5 PICMs or lipid nanoparticles. Transcriptome and histological analysis revealed that MFAP‐5 knockdown inhibited CAF‐related tumor vascularization, suggesting the anti‐angiogenic effect of RNA interference therapy. In conclusion, the developed multicompartment PICMs combining siMFAP‐5 and DES in a single polypept(o)ide micelle induce a specific knockdown of MFAP‐5 and demonstrate a potent antitumor efficacy (80% reduced tumor burden versus untreated control) in a clinically relevant HCC model. This article is protected by copyright. All rights reserved
Background Liver diseases of infectious and non-infectious etiology cause considerable morbidity and mortality, particularly in low- and middle-income countries (LMICs). However, data on the prevalence of liver diseases and underlying risk factors in LMICs are scarce. The objective of this study was to elucidate the occurrence of infectious diseases among individuals with chronic liver damage in a rural setting of Côte d’Ivoire. Methodology In 2021, we screened 696 individuals from four villages in the southern part of Côte d’Ivoire for hepatic fibrosis and steatosis, employing transient elastography (TE) and controlled attenuation parameter (CAP). We classified CAP ≥248 dB/m as steatosis, TE ≥7.2 kPa as fibrosis, and did subgroup analysis for participants with TE ranging from 7.2 kPa to 9.1 kPa. Clinical and microbiologic characteristics were compared to an age- and sex-matched control group (TE <6.0 kPa; n = 109). Stool samples were subjected to duplicate Kato-Katz thick smears for diagnosis of Schistosoma mansoni . Venous blood samples were examined for hepatitis B and hepatitis C virus. Additionally, an abdominal ultrasound examination was performed. Principal findings Among 684 individuals with valid TE measurements, TE screening identified hepatic pathologies in 149 participants (17% with fibrosis and 6% with steatosis). 419 participants were included for further analyses, of which 261 had complete microbiological analyses available. The prevalence of S . mansoni , hepatitis B, and hepatitis C were 30%, 14%, and 7%, respectively. Logistic regression analysis revealed higher odds for having TE results between 7.2 kPa and 9.1 kPa in individuals with S . mansoni infection (odds ratio [OR] = 3.02, 95% confidence interval [CI] = 1.58–5.76, P = 0.001), while HCV infection (OR = 5.02, 95% CI = 1.72–14.69, P = 0.003) and steatosis (OR = 4.62, 95% CI = 1.60–13.35, P = 0.005) were found to be risk factors for TE ≥9.2 kPa. Conclusions/Significance Besides viral hepatitis, S . mansoni also warrants consideration as a pathogen causing liver fibrosis in Côte d’Ivoire. In-depth diagnostic work-up among individuals with abnormal TE findings might be a cost-effective public health strategy.
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6,263 members
Holger Stenzhorn
  • Institut für Medizinische Biometrie, Epidemiologie und Medizinische Informatik
Carsten Kummerow
  • Fachbereich Biophysik
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Campus C4 2, 66123, Saarbrücken, Saarland, Germany
Head of institution
Prof. Dr. Manfred Schmitt
Phone
00496813022651
Fax
00496813024142