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  1. Book ; Thesis: Pathogenetische Rolle der Integrine alpha v beta 3 /alpha v beta 5 und deren Interaktionspartner bei Knochenmetastasen des Mammakarzinoms

    Bretschi, Maren

    2011  

    Author's details vorgelegt von Maren Bretschi
    Language German
    Size 102 S. : Ill., graph. Darst.
    Publishing country Germany
    Document type Book ; Thesis
    Thesis / German Habilitation thesis Heidelberg, Univ., Diss., 2011
    HBZ-ID HT017032347
    Database Catalogue ZB MED Medicine, Health

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  2. Article ; Online: Diffusion-weighted imaging and dynamic contrast-enhanced MRI of experimental breast cancer bone metastases--a correlation study with histology.

    Merz, Maximilian / Seyler, Lisa / Bretschi, Maren / Semmler, Wolfhard / Bäuerle, Tobias

    European journal of radiology

    2015  Volume 84, Issue 4, Page(s) 623–630

    Abstract: Purpose: To validate imaging parameters from diffusion-weighted imaging and dynamic contrast-enhanced MRI with immunohistology and to non-invasively assess microstructure of experimental breast cancer bone metastases.: Materials and methods: Animals ... ...

    Abstract Purpose: To validate imaging parameters from diffusion-weighted imaging and dynamic contrast-enhanced MRI with immunohistology and to non-invasively assess microstructure of experimental breast cancer bone metastases.
    Materials and methods: Animals bearing breast cancer bone metastases were imaged in a clinical 1.5 T MRI scanner. HASTE sequences were performed to calculate apparent diffusion coefficients. Saturation recovery turbo FLASH sequences were conducted while infusing 0.1 mmol/l Gd-DTPA for dynamic contrast-enhanced MRI to quantify parameters amplitude A and exchange rate constant kep. After imaging, bone metastases were analyzed immunohistologically.
    Results: We found correlations of the apparent diffusion coefficients from diffusion-weighted imaging with tumor cellularity as assessed with cell nuclei staining. Histological vessel maturity was correlated negatively with parameters A and kep from dynamic contrast-enhanced MRI. Tumor size correlated inversely with cell density and vessel permeability as well as positively with mean vessel calibers. Parameters from the rim of bone metastases differed significantly from values of the center.
    Conclusion: In vivo diffusion-weighted imaging and dynamic contrast-enhanced MRI in experimental bone metastases provide information about tumor cellularity and vascularity and correlate well with immunohistology.
    MeSH term(s) Animals ; Bone Neoplasms/diagnosis ; Bone Neoplasms/secondary ; Bone Neoplasms/ultrastructure ; Breast Neoplasms/pathology ; Contrast Media ; Diffusion Magnetic Resonance Imaging/methods ; Disease Models, Animal ; Gadolinium DTPA ; Image Enhancement/methods ; Magnetic Resonance Imaging/methods ; Male ; Rats ; Rats, Nude ; Reproducibility of Results
    Chemical Substances Contrast Media ; Gadolinium DTPA (K2I13DR72L)
    Language English
    Publishing date 2015-04
    Publishing country Ireland
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 138815-0
    ISSN 1872-7727 ; 0720-048X
    ISSN (online) 1872-7727
    ISSN 0720-048X
    DOI 10.1016/j.ejrad.2015.01.002
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article ; Online: Assessing treatment response of osteolytic lesions by manual volumetry, automatic segmentation, and RECIST in experimental bone metastases.

    Bretschi, Maren / Fränzle, Andrea / Merz, Maximilian / Hillengass, Jens / Semmler, Wolfhard / Bendl, Rolf / Bäuerle, Tobias

    Academic radiology

    2014  Volume 21, Issue 9, Page(s) 1177–1184

    Abstract: Rationale and objectives: Aim of the study was to compare between volumetric and unidimensional approaches for treatment response monitoring in a nude rat model of experimental bone metastases. For the volumetric approach, an automated segmentation ... ...

    Abstract Rationale and objectives: Aim of the study was to compare between volumetric and unidimensional approaches for treatment response monitoring in a nude rat model of experimental bone metastases. For the volumetric approach, an automated segmentation algorithm of osteolytic lesions was introduced and compared to manual volumetry.
    Material and methods: Nude rats bearing osteolytic metastases were treated with zoledronate and sunitinib and compared to controls. Treatment response was assessed longitudinally in vivo using flat-panel volumetric computed tomography at days 30, 35, 45, and 55 after tumor cell inoculation. The mean sizes and volumes of osteolytic lesions were determined according to response evaluation criteria in solid tumors (RECIST) and by automated and manual volumetry (software: MITK [The Medical Imaging Interaction Toolkit, Heidelberg, Germany] and VIRTUOS, Heidelberg, Germany).
    Results: In contrary to RECIST, the manual volumetric approach indicated a significant decrease in osteolytic lesion volume in response to treatment. The presented automatic segmentation algorithm for treatment monitoring identified bone metastases adequately and assessed changes in the osteolytic lesion volume over time according to manual volumetry.
    Conclusions: In an animal model, volumetric treatment response assessment of osteolytic bone metastases is superior to unidimensional measurements, and automated volumetric segmentation may be a valuable alternative to manual volume determination.
    MeSH term(s) Algorithms ; Animals ; Antineoplastic Agents/therapeutic use ; Bone Density Conservation Agents/therapeutic use ; Bone Neoplasms/diagnostic imaging ; Bone Neoplasms/drug therapy ; Cone-Beam Computed Tomography/methods ; Diphosphonates/therapeutic use ; Disease Models, Animal ; Follow-Up Studies ; Imidazoles/therapeutic use ; Indoles/therapeutic use ; Pyrroles/therapeutic use ; Radiographic Image Interpretation, Computer-Assisted/methods ; Rats ; Rats, Nude ; Reproducibility of Results ; Sensitivity and Specificity ; Treatment Outcome
    Chemical Substances Antineoplastic Agents ; Bone Density Conservation Agents ; Diphosphonates ; Imidazoles ; Indoles ; Pyrroles ; zoledronic acid (6XC1PAD3KF) ; sunitinib (V99T50803M)
    Language English
    Publishing date 2014-09
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 1355509-1
    ISSN 1878-4046 ; 1076-6332
    ISSN (online) 1878-4046
    ISSN 1076-6332
    DOI 10.1016/j.acra.2014.04.011
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Article ; Online: A quantification strategy for missing bone mass in case of osteolytic bone lesions.

    Fränzle, Andrea / Bretschi, Maren / Bäuerle, Tobias / Giske, Kristina / Hillengass, Jens / Bendl, Rolf

    Medical physics

    2013  Volume 40, Issue 12, Page(s) 123501

    Abstract: Purpose: Most of the patients who died of breast cancer have developed bone metastases. To understand the pathogenesis of bone metastases and to analyze treatment response of different bone remodeling therapies, preclinical animal models are examined. ... ...

    Abstract Purpose: Most of the patients who died of breast cancer have developed bone metastases. To understand the pathogenesis of bone metastases and to analyze treatment response of different bone remodeling therapies, preclinical animal models are examined. In breast cancer, bone metastases are often bone destructive. To assess treatment response of bone remodeling therapies, the volumes of these lesions have to be determined during the therapy process. The manual delineation of missing structures, especially if large parts are missing, is very time-consuming and not reproducible. Reproducibility is highly important to have comparable results during the therapy process. Therefore, a computerized approach is needed. Also for the preclinical research, a reproducible measurement of the lesions is essential. Here, the authors present an automated segmentation method for the measurement of missing bone mass in a preclinical rat model with bone metastases in the hind leg bones based on 3D CT scans.
    Methods: The affected bone structure is compared to a healthy model. Since in this preclinical rat trial the metastasis only occurs on the right hind legs, which is assured by using vessel clips, the authors use the left body side as a healthy model. The left femur is segmented with a statistical shape model which is initialised using the automatically segmented medullary cavity. The left tibia and fibula are segmented using volume growing starting at the tibia medullary cavity and stopping at the femur boundary. Masked images of both segmentations are mirrored along the median plane and transferred manually to the position of the affected bone by rigid registration. Affected bone and healthy model are compared based on their gray values. If the gray value of a voxel indicates bone mass in the healthy model and no bone in the affected bone, this voxel is considered to be osteolytic.
    Results: The lesion segmentations complete the missing bone structures in a reasonable way. The mean ratio vr∕vm of the reconstructed bone volume vr and the healthy model bone volume vm is 1.07, which indicates a good reconstruction of the modified bone.
    Conclusions: The qualitative and quantitative comparison of manual and semi-automated segmentation results have shown that comparing a modified bone structure with a healthy model can be used to identify and measure missing bone mass in a reproducible way.
    MeSH term(s) Animals ; Bone Neoplasms/diagnostic imaging ; Bone Neoplasms/physiopathology ; Bone Neoplasms/secondary ; Image Processing, Computer-Assisted/methods ; Leg Bones/diagnostic imaging ; Leg Bones/physiopathology ; Osteolysis/diagnostic imaging ; Rats ; Tomography, X-Ray Computed/methods
    Language English
    Publishing date 2013-12
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 188780-4
    ISSN 2473-4209 ; 0094-2405
    ISSN (online) 2473-4209
    ISSN 0094-2405
    DOI 10.1118/1.4828843
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article ; Online: Cilengitide inhibits metastatic bone colonization in a nude rat model.

    Bretschi, Maren / Merz, Maximilian / Komljenovic, Dorde / Berger, Martin R / Semmler, Wolfhard / Bäuerle, Tobias

    Oncology reports

    2011  Volume 26, Issue 4, Page(s) 843–851

    Abstract: Integrins αvβ3 and αvβ5 are considered to play an important role in the pathogenesis of breast cancer bone metastases. This study investigates the effects of the αvβ3/αvβ5 integrin-specific inhibitor cilengitide during early metastatic bone colonization. ...

    Abstract Integrins αvβ3 and αvβ5 are considered to play an important role in the pathogenesis of breast cancer bone metastases. This study investigates the effects of the αvβ3/αvβ5 integrin-specific inhibitor cilengitide during early metastatic bone colonization. The impact of cilengitide on the migration, invasion and proliferation of MDA-MB-231 human breast carcinoma cells as well as on bone resorption by osteoclasts was investigated in vitro. For in vivo experiments, nude rats were treated with cilengitide for 30 days starting one day after site-specific tumor cell inoculation in the hind leg, and the course of metastatic changes in bone was followed using flat-panel volumetric computed tomography (VCT) and magnetic resonance imaging (MRI). Vascular changes in bone metastases were investigated using dynamic contrast-enhanced (DCE-) MRI-derived parameters amplitude A and exchange rate coefficient kep. In vitro, cilengitide treatment resulted in a decrease in proliferation, migration and invasion of MDA-MB-231 cells, as well as of osteoclast activity. In vivo, the development of bone metastasis in the hind leg of rats was not prevented by adjuvant cilengitide treatment, but cilengitide reduced the volumes of osteolytic lesions and respective soft tissue tumors of developing bone metastases as assessed with VCT and MRI, respectively. DCE-MRI revealed significant changes in the A and kep parameters including decreased relative blood volume and increased vessel permeability after cilengitide treatment indicating vessel remodeling. In conclusion, during early pathogenic processes of bone colonization, cilengitide treatment exerted effects on tumor cells, osteoclasts and vasculature reducing the skeletal lesion size of experimental skeletal metastases.
    MeSH term(s) Animals ; Bone Neoplasms/blood supply ; Bone Neoplasms/metabolism ; Bone Neoplasms/prevention & control ; Bone Neoplasms/secondary ; Bone Resorption/drug therapy ; Bone Resorption/metabolism ; Bone Resorption/pathology ; Breast Neoplasms/drug therapy ; Breast Neoplasms/pathology ; Cell Growth Processes/drug effects ; Cell Line, Tumor ; Cell Movement/drug effects ; Disease Models, Animal ; Female ; Humans ; Magnetic Resonance Imaging ; Neoplasm Invasiveness ; Osteoclasts/metabolism ; Osteoclasts/pathology ; Rats ; Rats, Nude ; Snake Venoms/pharmacology ; Xenograft Model Antitumor Assays
    Chemical Substances Snake Venoms ; Cilengitide (4EDF46E4GI)
    Language English
    Publishing date 2011-10
    Publishing country Greece
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 1222484-4
    ISSN 1791-2431 ; 1021-335X
    ISSN (online) 1791-2431
    ISSN 1021-335X
    DOI 10.3892/or.2011.1373
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  6. Article ; Online: A novel PET tracer for the imaging of αvβ3 and αvβ5 integrins in experimental breast cancer bone metastases.

    Mühlhausen, Ute / Komljenovic, Dorde / Bretschi, Maren / Leotta, Karin / Eisenhut, Michael / Semmler, Wolfhard / Bäuerle, Tobias

    Contrast media & molecular imaging

    2011  Volume 6, Issue 6, Page(s) 413–420

    Abstract: The aim of this study was the evaluation of (68)Ga-DOTA-E-[c(RGDfK)](2) as a novel PET tracer to image αvβ3 and αvβ5 integrins. For this purpose, DOTA-E-[c(RGDfK)](2) was labeled with (68)Ga, which was obtained from a (68)Ge/(68)Ga generator, purified by ...

    Abstract The aim of this study was the evaluation of (68)Ga-DOTA-E-[c(RGDfK)](2) as a novel PET tracer to image αvβ3 and αvβ5 integrins. For this purpose, DOTA-E-[c(RGDfK)](2) was labeled with (68)Ga, which was obtained from a (68)Ge/(68)Ga generator, purified by solid-phase extraction and the radiochemical purity analyzed by radio-RP-HPLC. (68) Ga-DOTA-E-[c(RGDfK)](2) was obtained reproducibly in radiochemical yields of 60 ± 6% and with an excellent radiochemical purity of >99%. In nude rats bearing bone metastases after injection of MDA-MB-231 human breast cancer cells, biodistribution studies were performed to evaluate the accumulation of the radiotracer in selected organs, blood and bone metastases 0.5, 1, 2 and 3 h post injection. A rapid uptake into the bone metastases and rapid blood clearance was observed, resulting in tumor-blood ratios of up to 26.6 (3 h post injection) and tumor-muscle ratios of up to 7.9 (3 h post injection). A blocking experiment with coinjected αvβ3/αvβ5 antagonist showed the tumor uptake to be receptor-specific. In an initial in vivo micro PET evaluation of the tracer using the same animal model, the bone metastasis was clearly visualized. These results suggest that (68)Ga-DOTA-E-[c(RGDfK)](2) is a promising PET tracer suitable for the imaging of αvβ3 and αvβ5 integrins in bone metastases. This novel PET tracer should be further evaluated concerning its usefulness for early detection of bone metastases and monitoring treatment response of these lesions.
    MeSH term(s) Animals ; Bone Neoplasms/diagnostic imaging ; Bone Neoplasms/secondary ; Breast Neoplasms/diagnostic imaging ; Breast Neoplasms/pathology ; Cell Line, Tumor ; Coordination Complexes/chemistry ; Coordination Complexes/pharmacokinetics ; Female ; Gallium Radioisotopes ; Humans ; Integrin alphaVbeta3/analysis ; Integrin alphaVbeta3/antagonists & inhibitors ; Neoplasms, Experimental/diagnostic imaging ; Peptides, Cyclic/chemistry ; Peptides, Cyclic/pharmacokinetics ; Positron-Emission Tomography/methods ; Radioactive Tracers ; Rats ; Receptors, Vitronectin/analysis ; Receptors, Vitronectin/antagonists & inhibitors ; Tissue Distribution
    Chemical Substances 68Ga-DOTA-E-(c(RGDfK))2 ; Coordination Complexes ; Gallium Radioisotopes ; Integrin alphaVbeta3 ; Peptides, Cyclic ; Radioactive Tracers ; Receptors, Vitronectin ; integrin alphaVbeta5
    Language English
    Publishing date 2011-11
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 2232678-9
    ISSN 1555-4317 ; 1555-4309
    ISSN (online) 1555-4317
    ISSN 1555-4309
    DOI 10.1002/cmmi.435
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  7. Article ; Online: Cilengitide affects tumor compartment, vascularization and microenvironment in experimental bone metastases as shown by longitudinal ¹⁸F-FDG PET and gene expression analysis.

    Bretschi, Maren / Cheng, Caixia / Witt, Hendrik / Dimitrakopoulou-Strauss, Antonia / Strauss, Ludwig G / Semmler, Wolfhard / Bäuerle, Tobias

    Journal of cancer research and clinical oncology

    2012  Volume 139, Issue 4, Page(s) 573–583

    Abstract: Purpose: Aim of this study was to investigate the specific treatment effects of inhibiting αvβ3/αvβ5 integrins by cilengitide in an animal model of breast cancer bone metastases using dynamic (18)F-FDG PET and gene expression analysis.: Methods: For ... ...

    Abstract Purpose: Aim of this study was to investigate the specific treatment effects of inhibiting αvβ3/αvβ5 integrins by cilengitide in an animal model of breast cancer bone metastases using dynamic (18)F-FDG PET and gene expression analysis.
    Methods: For this purpose, nude rats bearing bone metastases were treated with cilengitide, a small molecule inhibitor of αvβ3 and αvβ5 integrins, from day 30 to 55 after tumor cell inoculation of MDA-MB-231 breast cancer cells (25 mg/kg, 5 days per week; n = 8 rats) and compared to control rats (n = 8). Dynamic (18)F-FDG PET data were assessed at days 30, 35 and 55 after tumor cell inoculation determining the vascular fraction VB and the metabolic variables k1-k4. At day 55, genome-wide mRNA expression analysis was performed to assess the treatment-specific expression changes from cilengitide-treated and control rats.
    Results: In a longitudinal (18)F-FDG PET study, the vascular fraction VB was significantly decreased in bone metastases between days 30/35, 30/55 and 35/55, whereas the kinetic parameters k1 and k4 were significantly decreased between days 30/55 in skeletal lesions of treated animals. Gene expression analysis from bone metastases at day 55 revealed that tumor-produced integrins (αvβ5) as well as factors relevant for angiogenesis (αvβ3, VEGF, PDGF), bone resorption (PTHrP and RANKL), extracellular matrix remodeling (collagen, CD44) and bone marrow microenvironment (CXCR4) were significantly reduced upon therapy with cilengitide.
    Conclusions: Here, we provide evidence that cilengitide inhibits pivotal factors of all compartments of bone metastases including tumor cells, vasculature and bone microenvironment in vivo and by whole-genome transcriptome analysis.
    MeSH term(s) Animals ; Biomarkers, Tumor/genetics ; Biomarkers, Tumor/metabolism ; Bone Neoplasms/diagnostic imaging ; Bone Neoplasms/drug therapy ; Bone Neoplasms/secondary ; Breast Neoplasms/diagnostic imaging ; Breast Neoplasms/drug therapy ; Breast Neoplasms/pathology ; Female ; Fluorodeoxyglucose F18 ; Gene Expression Profiling ; Humans ; Integrin alphaVbeta3/genetics ; Integrin alphaVbeta3/metabolism ; Longitudinal Studies ; Male ; Neovascularization, Pathologic/drug therapy ; Oligonucleotide Array Sequence Analysis ; Positron-Emission Tomography ; RNA, Messenger/genetics ; Radiopharmaceuticals ; Rats ; Rats, Nude ; Real-Time Polymerase Chain Reaction ; Receptors, Vitronectin/genetics ; Receptors, Vitronectin/metabolism ; Reverse Transcriptase Polymerase Chain Reaction ; Snake Venoms/pharmacology ; Tumor Cells, Cultured ; Tumor Microenvironment/drug effects
    Chemical Substances Biomarkers, Tumor ; Integrin alphaVbeta3 ; RNA, Messenger ; Radiopharmaceuticals ; Receptors, Vitronectin ; Snake Venoms ; integrin alphaVbeta5 ; Fluorodeoxyglucose F18 (0Z5B2CJX4D) ; Cilengitide (4EDF46E4GI)
    Language English
    Publishing date 2012-12-11
    Publishing country Germany
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 134792-5
    ISSN 1432-1335 ; 0171-5216 ; 0084-5353 ; 0943-9382
    ISSN (online) 1432-1335
    ISSN 0171-5216 ; 0084-5353 ; 0943-9382
    DOI 10.1007/s00432-012-1360-6
    Database MEDical Literature Analysis and Retrieval System OnLINE

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