Publications by authors named "Anja Conrad"

5 Publications

  • Page 1 of 1

MALDI-2 Mass Spectrometry and Immunohistochemistry Imaging of Gb3Cer, Gb4Cer, and Further Glycosphingolipids in Human Colorectal Cancer Tissue.

Anal Chem 2020 05 4;92(10):7096-7105. Epub 2020 May 4.

Institute of Hygiene, University of Münster, Robert-Koch-Str. 41, 48149 Münster, Germany.

The main cellular receptors of Shiga toxins (Stxs), the neutral glycosphingolipids (GSLs), globotriaosylceramide (Gb3Cer/CD77) and globotetraosylceramide (Gb4Cer), are significantly upregulated in about half of the human colorectal carcinomas (CRC) and in other cancers. Therefore, conjugates exploiting the Gb3Cer/Gb4Cer-binding B subunit of Stx (StxB) have attracted great interest for both diagnostic and adjuvant therapeutic interventions. Moreover, fucosylated GSLs were recognized as potential tumor-associated targets. One obstacle to a broader use of these receptor/ligand systems is that the contribution of specific GSLs to tumorigenesis, in particular, in the context of an altered lipid metabolism, is only poorly understood. A second is that also nondiseased organs (e.g., kidney) and blood vessels can express high levels of certain GSLs, not least Gb3Cer/Gb4Cer. Here, we used, in a proof-of-concept study, matrix-assisted laser desorption/ionization mass spectrometry imaging combined with laser-induced postionization (MALDI-2-MSI) to simultaneously visualize the distribution of several Gb3Cer/Gb4Cer lipoforms and those of related GSLs (e.g., Gb3Cer/Gb4Cer precursors and fucosylated GSLs) in tissue biopsies from three CRC patients. Using MALDI-2 and StxB-based immunofluorescence microscopy, Gb3Cer and Gb4Cer were mainly found in dedifferentiated tumor cell areas, tumor stroma, and tumor-infiltrating blood vessels. Notably, fucosylated GSL such as Fuc-(n)Lc4Cer generally showed a highly localized expression in dysplastic glands and indian file-like cells infiltrating adipose tissue. Our "molecular histology" approach could support stratifying patients for intratumoral GSL expression to identify an optimal therapeutic strategy. The improved chemical coverage by MALDI-2 can also help to improve our understanding of the molecular basis of tumor development and GSL metabolism.
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http://dx.doi.org/10.1021/acs.analchem.0c00480DOI Listing
May 2020

BarrettNET-a prospective registry for risk estimation of patients with Barrett's esophagus to progress to adenocarcinoma.

Dis Esophagus 2019 Aug;32(8)

Klinik und Poliklinik für Innere Medizin II, University Hospital rechts der Isar, Technical University of Munich.

Risk stratification in patients with Barrett's esophagus (BE) to prevent the development of esophageal adenocarcinoma (EAC) is an unsolved task. The incidence of EAC and BE is increasing and patients are still at unknown risk. BarrettNET is an ongoing multicenter prospective cohort study initiated to identify and validate molecular and clinical biomarkers that allow a more personalized surveillance strategy for patients with BE. For BarrettNET participants are recruited in 20 study centers throughout Germany, to be followed for progression to dysplasia (low-grade dysplasia or high-grade dysplasia) or EAC for >10 years. The study instruments comprise self-administered epidemiological information (containing data on demographics, lifestyle factors, and health), as well as biological specimens, i.e., blood-based samples, esophageal tissue biopsies, and feces and saliva samples. In follow-up visits according to the individual surveillance plan of the participants, sample collection is repeated. The standardized collection and processing of the specimen guarantee the highest sample quality. Via a mobile accessible database, the documentation of inclusion, epidemiological data, and pathological disease status are recorded subsequently. Currently the BarrettNET registry includes 560 participants (23.1% women and 76.9% men, aged 22-92 years) with a median follow-up of 951 days. Both the design and the size of BarrettNET offer the advantage of answering research questions regarding potential causes of disease progression from BE to EAC. Here all the integrated methods and materials of BarrettNET are presented and reviewed to introduce this valuable German registry.
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http://dx.doi.org/10.1093/dote/doz024DOI Listing
August 2019

Cell-type specific MyD88 signaling is required for intestinal tumor initiation and progression to malignancy.

Oncoimmunology 2018;7(8):e1466770. Epub 2018 Jun 11.

Technical University of Munich, School of Medicine, Klinikum rechts der Isar, Department of Surgery; Ismaninger Str. 22, Munich, Germany.

The signal adapter MyD88, an essential component of Toll-like receptor (TLR) signaling, is important for gut-microbiome interactions. However, its contribution to cancer and its cell-type specific functions are controversially discussed. Therefore, we generated new tissue-specific mouse models and analyzed the clinical importance in human colorectal cancer. A gene-trap was inserted into the murine gene (Myd88), yielding MyD88-deficient background with Cre-mediated re-expression in myeloid (MYEL) or intestinal epithelial cells (IECs). These lines were bred with the Apc model that develops invasive adenocarcinoma and analyzed at 12 months. Further, two patient collectives of colorectal cancer (n = 61, and n = 633) were analyzed for expression of Myd88 and TLRs. MyD88 expression was significantly increased in carcinomas, and increased intratumoral levels of MyD88 and TLR pathway components were associated with significantly shorter disease-free ( = .011), and overall survival ( < .0001). In accordance, fully MyD88-deficient mice showed highly significantly decreased tumor incidence, tumor numbers, increased survival, and, importantly, fully lacked malignant lesions. Thus, MyD88 is essential for tumorigenesis and especially progression to malignancy. Tissue-specific re-expression of MyD88 highly significantly increased tumor initiation by differing mechanisms. In intestinal epithelia, MyD88 enhanced epithelial turnover, whereas in myeloid cells, it led to increased production of tumor- and stemness-enhancing cytokines, significantly associated with altered expression of adaptive immune genes. However, neither re-expression of MyD88 in IECs or myeloid cells was sufficient for malignant progression to carcinoma. Thus, MyD88 crucially contributes to colorectal cancer initiation and progression with non-redundant and cell-type specific functions, constituting an attractive therapeutic target.
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http://dx.doi.org/10.1080/2162402X.2018.1466770DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6136867PMC
June 2018

Influence of Renal Impairment on the Pharmacokinetics of Afatinib: An Open-Label, Single-Dose Study.

Eur J Drug Metab Pharmacokinet 2017 Jun;42(3):461-469

Translational Medicine and Clinical Pharmacology, Boehringer Ingelheim Pharma GmbH & Co KG, Birkendorfer Strasse 65, 88397, Biberach an der Riss, Germany.

Background And Objective: Afatinib is an oral irreversible ErbB-Family Blocker indicated for treatment of patients with EGFR mutation positive advanced non-small cell lung cancer. This trial assessed whether renal impairment influences the pharmacokinetics and safety of afatinib.

Methods: This was an open-label, single-dose study. Pharmacokinetic parameters after afatinib 40 mg were investigated in subjects with moderate (n = 8) or severe (n = 8) renal impairment (estimated glomerular filtration rate 30-59 mL/min/1.73 m and 15-29 mL/min/1.73 m, respectively) and healthy matched controls (n = 14). Plasma and urine samples were collected before and up to 14 days after dosing for pharmacokinetic and plasma protein-binding assessment. Primary endpoints were area under the plasma concentration-time curve from time zero to the last quantifiable concentration (AUC) and maximum plasma concentration (C ) between subjects with renal impairment and healthy matched controls.

Results: Pharmacokinetic profiles and plasma protein binding were similar in all groups. The extent of exposure, as indicated by AUC and C , was generally similar between the matched treatment groups, with the exception of the geometric mean ratio of AUC for subjects with severe renal impairment, which showed a trend towards a higher value compared with matched healthy subjects (150.0 % [90 % CI 105.3-213.7]) Inter-individual variability was moderate (geometric mean coefficient of variation 28-39 % for moderate impairment, 34-42 % for severe impairment). Afatinib was well tolerated and urinary excretion was minimal.

Conclusion: Moderate-to-severe renal impairment had a minor influence on the pharmacokinetics of afatinib that was within the observed inter-individual variability, suggesting that afatinib treatment can be considered in this patient population. Registered at ClinicalTrials.gov as NCT02096718.
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http://dx.doi.org/10.1007/s13318-016-0359-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5423921PMC
June 2017

Evaluation of the dedicated Frontier coronary bifurcation stent: A matched pair analysis with drug-eluting and bare metal stents.

Clin Res Cardiol 2008 Apr 28;97(4):260-5. Epub 2007 Nov 28.

Medical Clinic II, University of Schleswig-Holstein, Campus Lübeck, Ratzeburger Allee 160, 23538 Lübeck, Germany.

Treatment of coronary bifurcation lesions (CBL) remains challenging. This study sought to evaluate a novel dedicated stent system (Frontier stent) by angiographic and clinical comparison with the provisional T-stenting technique using drug-eluting (DES) and bare metal stents (BMS). The study group comprised 105 CBL in 105 patients. 35 consecutive CBL were treated with the Frontier system. The control group of 70 CBL (35 DES, 35 BMS) was pair matched with the former group stratified by the type of CBL (Medina classification) and the reference diameter of the main branch (MB). Clinical, procedural, and quantitative angiographic data (QCA) were obtained in all patients. A follow-up angiography 6 +/- 2-month post-index intervention was performed in 84/105 (80%) patients, clinical 6-month follow-up was available in all patients (100%). All Frontier stent procedures were clinically and angiographically successful. Post-procedural QCA analysis of the MB and the side branches revealed comparable minimal lumen diameters (MLDs) between groups. Moreover, contrast use and radiation exposure were not different between groups. DES use, however, was associated with a significantly lower late lumen (LL) loss in the main and the side branch as compared to the Frontier stent and BMS group. Likewise, MACE rates were lowest in the DES group (6%, P < 0.05 vs. BMS) as compared to the Frontier stent (9%) and the BMS group (16%). The Frontier stent accomplishes treatment of CBL with excellent acute clinical, procedural, and angiographic results. Provisional T-stenting using DES provides superior clinical and angiographic long-term results as compared to BMS and Frontier stents. The results of next generation CBL systems combining a dedicated specific CBL design with DES surfaces are to be awaited.
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http://dx.doi.org/10.1007/s00392-007-0619-4DOI Listing
April 2008
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