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15 result(s) for "Claus-Christian, Glüer"
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Romosozumab significantly improves vertebral cortical bone mass and structure compared with teriparatide, whereas both treatments increase vertebral trabecular bone mass similarly: high-resolution quantitative computed tomography analyses of randomized controlled trial results in postmenopausal women with low bone mineral density
Romosozumab, a sclerostin inhibitor, exerts a dual effect of increasing bone formation while decreasing bone resorption to rapidly increase bone mineral density (BMD) and reduce fracture risk in postmenopausal women. Iterative Convolution OptimizatioN (ICON) allows accurate calculation of deconvolved cortical thickness from high-resolution quantitative computed tomography (HR-QCT) scanning. This study employed HR-QCT to evaluate compartmental (including endosteal and periosteal) changes in the vertebral cortical shell in postmenopausal women who received romosozumab, teriparatide, or placebo. In a subset of a phase 2, randomized study (NCT00896532), women (55-85 yr) with low BMD (T-score ≤ −2.0, but not <−3.5, at the lumbar spine, total hip, or femoral neck) treated with subcutaneous (SC) romosozumab monthly (210 mg; n = 11), SC teriparatide daily (20 μg; n = 12), or SC placebo (n = 8) had spine HR-QCT scans at baseline and Month 12 to assess treatment effects on cortical and cancellous compartments of the T12 vertebra. HR-QCT was obtained at 120 kVp and 360 mAs. Cortical changes were evaluated using ICON software. At Month 12, compared to teriparatide and placebo, romosozumab treatment was associated with greater gains in all cortical parameters. Changes in cancellous bone parameters were similar with romosozumab and teriparatide. Romosozumab significantly increased cortical thickness (mean ± SD; 53 ± 18%) and the magnitude of this change was greater than that of teriparatide (20 ± 13%) and placebo (3 ± 6%); all p < .001. With romosozumab, cortical BMC and apparent cortical BMD were also significantly increased from baseline, and compared to teriparatide and placebo (all p < .001). These changes occurred through endosteal and periosteal bone matrix apposition, with greatest changes seen at the endosteal surface. The location and magnitude of these changes likely form the basis of the rapid improvement in bone mass, structure, and strength that contribute to romosozumab’s rapid vertebral fracture risk reduction efficacy; however, conclusions are limited by the small sample size.
Exploring the Usability of α-MSH-SM-Liposome as an Imaging Agent to Study Biodegradable Bone Implants In Vivo
Novel biodegradable metal alloys are increasingly used as implant materials. The implantation can be accompanied by an inflammatory response to a foreign object. For studying inflammation in the implantation area, non-invasive imaging methods are needed. In vivo imaging for the implanted area and its surroundings will provide beneficiary information to understand implant-related inflammation and help to monitor it. Therefore, inflammation-sensitive fluorescent liposomes in rats were tested in the presence of an implant to evaluate their usability in studying inflammation. The sphingomyelin-containing liposomes carrying alpha-melanocyte-stimulating hormone (α-MSH)-peptide were tested in a rat bone implant model. The liposome interaction with implant material (Mg-10Gd) was analyzed with Mg-based implant material (Mg-10Gd) in vitro. The liposome uptake process was studied in the bone-marrow-derived macrophages in vitro. Finally, this liposomal tracer was tested in vivo. It was found that α-MSH coupled sphingomyelin-containing liposomes and the Mg-10Gd implant did not have any disturbing influence on each other. The clearance of liposomes was observed in the presence of an inert and biodegradable implant. The degradable Mg-10Gd was used as an alloy example; however, the presented imaging system offers a new possible use of α-MSH-SM-liposomes as tools for investigating implant responses.
The novel TRAIL-receptor agonist APG350 exerts superior therapeutic activity in pancreatic cancer cells
Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) has raised attention as a novel anticancer therapeutic as it induces apoptosis preferentially in tumor cells. However, first-generation TRAIL-receptor agonists (TRAs), comprising recombinant TRAIL and agonistic receptor-specific antibodies, have not demonstrated anticancer activity in clinical studies. In fact, cancer cells are often resistant to conventional TRAs. Therefore, in addition to TRAIL-sensitizing strategies, next-generation TRAs with superior apoptotic activity are warranted. APG350 is a novel, highly potent TRAIL-receptor agonist with a hexavalent binding mode allowing the clustering of six TRAIL-receptors per drug molecule. Here we report on preclinical in vitro and in vivo studies testing the activity of APG350 on pancreatic ductal adenocarcinoma (PDAC) cells. We found that APG350 potently induced apoptosis of Colo357, PancTuI and Panc89 cells in vitro. In addition, APG350 treatment activated non-canonical TRAIL signaling pathways (MAPK, p38, JNK, ERK1/ERK2 and NF-κB) and induced the secretion of IL-8. Stable overexpression of Bcl-xL inhibited APG350-induced cell death and augmented activation of non-canonical pathways. Intriguingly, pre-treatment of Bcl-xL-overexpressing cells with the BH3-mimic Navitoclax restored their sensitivity to APG350. To study the effects of APG350 on PDAC cells in vivo, we applied two different orthotopic xenotransplantation mouse models, with and without primary tumor resection, representing adjuvant and palliative treatment regimes, respectively. APG350 treatment of established tumors (palliative treatment) significantly reduced tumor burden. These effects, however, were not seen in tumors with enforced overexpression of Bcl-xL. Upon primary tumor resection and subsequent APG350 treatment (adjuvant therapy), APG350 limited recurrent tumor growth and metastases. Importantly, therapeutic efficacy of APG350 treatment was more effective compared with treatment with soluble TRAIL in both models. In conclusion, APG350 represents a promising next-generation TRA for the treatment of PDAC. Moreover, our results suggest that combining APG350 with Navitoclax might be a succesfull strategy for cancers harboring mitochondrial apoptosis resistance.
Age-Dependent Changes in Resting Energy Expenditure (REE): Insights from Detailed Body Composition Analysis in Normal and Overweight Healthy Caucasians
Age-related changes in organ and tissue masses may add to changes in the relationship between resting energy expenditure (REE) and fat free mass (FFM) in normal and overweight healthy Caucasians. Secondary analysis using cross-sectional data of 714 healthy normal and overweight Caucasian subjects (age 18–83 years) with comprehensive information on FFM, organ and tissue masses (as assessed by magnetic resonance imaging (MRI)), body density (as assessed by Air Displacement Plethysmography (ADP)) and hydration (as assessed by deuterium dilution (D2O)) and REE (as assessed by indirect calorimetry). High metabolic rate organs (HMR) summarized brain, heart, liver and kidney masses. Ratios of HMR organs and muscle mass (MM) in relation to FFM were considered. REE was calculated (REEc) using organ and tissue masses times their specific metabolic rates. REE, FFM, specific metabolic rates, the REE-FFM relationship, HOMA, CRP, and thyroid hormone levels change with age. The age-related decrease in FFM explained 59.7% of decreases in REE. Mean residuals of the REE-FFM association were positive in young adults but became negative in older subjects. When compared to young adults, proportions of MM to FFM decreased with age, whereas contributions of liver and heart did not differ between age groups. HOMA, TSH and inflammation (plasma CRP-levels) explained 4.2%, 2.0% and 1.4% of the variance in the REE-FFM residuals, but age and plasma T3-levels had no effects. HMR to FFM and MM to FFM ratios together added 11.8% on to the variance of REE-FFM residuals. Differences between REE and REEc increased with age, suggesting age-related changes in specific metabolic rates of organs and tissues. This bias was partly explained by plasmaT3-levels. Age-related changes in REE are explained by (i) decreases in fat free mass; (ii) a decrease in the contributions of organ and muscle masses to FFM; and (iii) decreases in specific organ and tissue metabolic rates. Age-dependent changes in the REE-FFMassociation are explained by composition of FFM, inflammation and thyroid hormones.
Dasatinib prevents skeletal metastasis of osteotropic MDA-MB-231 cells in a xenograft mouse model
PurposeBone metastasis in breast cancer has been linked to activity of c-Src kinase, one of the extensively explored tyrosine kinases in cell biology. The impact of TNF-related apoptosis inducing ligand (TRAIL) and TRAIL receptors has just recently been integrated into this conception.MethodsAn osteotropic clone of MDA-MB-231 cells simulated a model for bone metastasis of triple-negative breast cancer (TNBC). The effects of Dasatinib, a clinically established inhibitor of Src kinases family and Abl were evaluated in vitro and in vivo. In vivo effects of Dasatinib treatment on the occurrence of skeletal metastases were tested in a xenograft mouse model after intra-cardiac injection of osteotropic MDA-MB-231-cells. Ex vivo analyses of the bone sections confirmed intraosseous growth of metastases and allowed determination of osteoclastic activity.ResultsTreatment of osteotropic MDA-MB-231 cells with Dasatinib inhibited proliferation rates in vitro. A shift in TRAIL-receptor expression towards an induction of oncogenic TRAIL-R2 was observed. In vivo, 15 of 30 mice received an intra-peritoneal treatment with Dasatinib. These mice showed significantly less skeletal metastases in bioluminescence scans. Moreover, a pronounced increase in bone volume was observed in the treatment group, as detected by µ-Computed Tomography. Dasatinib treatment also led to a greater increase in bone density in tibiae without metastatic affection, which was accompanied by reduced recruitment of osteoclasts.ConclusionOur observations support the concept of utilizing Dasatinib in targeting early-stage bone metastatic TNBC and sustaining bone health.
Biological Properties of Iron Oxide Nanoparticles for Cellular and Molecular Magnetic Resonance Imaging
Superparamagnetic iron-oxide particles (SPIO) are used in different ways as contrast agents for magnetic resonance imaging (MRI): Particles with high nonspecific uptake are required for unspecific labeling of phagocytic cells whereas those that target specific molecules need to have very low unspecific cellular uptake. We compared iron-oxide particles with different core materials (magnetite, maghemite), different coatings (none, dextran, carboxydextran, polystyrene) and different hydrodynamic diameters (20–850 nm) for internalization kinetics, release of internalized particles, toxicity, localization of particles and ability to generate contrast in MRI. Particle uptake was investigated with U118 glioma cells und human umbilical vein endothelial cells (HUVEC), which exhibit different phagocytic properties. In both cell types, the contrast agents Resovist, B102, non-coated Fe3O4 particles and microspheres were better internalized than dextran-coated Nanomag particles. SPIO uptake into the cells increased with particle/iron concentrations. Maximum intracellular accumulation of iron particles was observed between 24 h to 36 h of exposure. Most particles were retained in the cells for at least two weeks, were deeply internalized, and only few remained adsorbed at the cell surface. Internalized particles clustered in the cytosol of the cells. Furthermore, all particles showed a low toxicity. By MRI, monolayers consisting of 5000 Resovist-labeled cells could easily be visualized. Thus, for unspecific cell labeling, Resovist and microspheres show the highest potential, whereas Nanomag particles are promising contrast agents for target-specific labeling.
Increased survival rate by local release of diclofenac in a murine model of recurrent oral carcinoma
Despite aggressive treatment with radiation and combination chemotherapy following tumor resection, the 5-year survival rate for patients with head and neck cancer is at best only 50%. In this study, we examined the therapeutic potential of localized release of diclofenac from electrospun nanofibers generated from poly(D,L-lactide-co-glycolide) polymer. Diclofenac was chosen since anti-inflammatory agents that inhibit cyclooxygenase have shown great potential in their ability to directly inhibit tumor growth as well as suppress inflammation-mediated tumor growth. A mouse resection model of oral carcinoma was developed by establishing tumor growth in the oral cavity by ultrasound-guided injection of 1 million SCC-9 cells in the floor of the mouth. Following resection, mice were allocated into four groups with the following treatment: 1) no treatment, 2) implanted scaffolds without diclofenac, 3) implanted scaffolds loaded with diclofenac, and 4) diclofenac given orally. Small animal ultrasound and magnetic resonance imaging were utilized for longitudinal determination of tumor recurrence. At the end of 7 weeks following tumor resection, 33% of mice with diclofenac-loaded scaffolds had a recurrent tumor, in comparison to 90%-100% of the mice in the other three groups. At this time point, mice with diclofenac-releasing scaffolds showed 89% survival rate, while the other groups showed survival rates of 10%-25%. Immunohistochemical staining of recurrent tumors revealed a near 10-fold decrease in the proliferation marker Ki-67 in the tumors derived from mice with diclofenac-releasing scaffolds. In summary, the local application of diclofenac in an orthotopic mouse tumor resection model of oral cancer reduced tumor recurrence with significant improvement in survival over a 7-week study period following tumor resection. Local drug release of anti-inflammatory agents should be investigated as a therapeutic option in the prevention of tumor recurrence in oral squamous carcinoma.
A variant in IL6ST with a selective IL-11 signaling defect in human and mouse
The GP130 cytokine receptor subunit encoded by IL6ST is the shared receptor for ten cytokines of the IL-6 family. We describe a homozygous non-synonymous variant in IL6ST (p.R281Q) in a patient with craniosynostosis and retained deciduous teeth. We characterize the impact of the variant on cytokine signaling in vitro using transfected cell lines as well as primary patient-derived cells and support these findings using a mouse model with the corresponding genome-edited variant Il6st p.R279Q. We show that human GP130 p.R281Q is associated with selective loss of IL-11 signaling without affecting IL-6, IL-27, OSM, LIF, CT1, CLC, and CNTF signaling. In mice Il6st p.R279Q lowers litter size and causes facial synostosis and teeth abnormalities. The effect on IL-11 signaling caused by the GP130 variant shows incomplete penetrance but phenocopies aspects of IL11RA deficiency in humans and mice. Our data show that a genetic variant in a pleiotropic cytokine receptor can have remarkably selective defects.
Long-Term Reproducibility of BMD-Measurements with Clinical QCT Using Simultaneous and Asynchronous Calibration Methods and Different Measurement and Reconstruction Protocols
Osteoporosis is underdiagnosed and undertreated. To improve timely fracture risk assessment optimized densitometry methods are required such as opportunistic spinal quantitative computed tomography (QCT). However, it is unclear how to best calibrate these scans and correct for potential scanner drift of QCT when used for monitoring bone mineral density (BMD) changes. We compared gold standard simultaneous calibration with asynchronous calibration methods, assessing mid-term (12 weeks) and long-term (1.5 years) reproducibility of BMD measurements. Cortical and trabecular compartments of the European Spine Phantom were studied with ten different protocols including low dose and high resolution (HR)-modes. Based on weekly phantom data, we compared simultaneous calibration to asynchronous single (termed global) or monthly calibration. The accuracy was better for trabecular measurements than for cortical measurements for all calibration methods. Reproducibility was excellent for all methods and slightly better for asynchronous than for simultaneous calibration both for trabecular and cortical bone. For HR protocols, reproducibility was better than for low dose measurements. In trabecular compartments averaged HR-BMD remained stable for global (− 0.1%/year, ns) but not for simultaneous calibration (− 1.5%/year, p < 0.001). No significant drifts could be detected for averaged low dose BMD (− 0.9 to + 0.8%/year) for either calibration method. Our data suggest that with regard to precision and accuracy measurements with asynchronous calibration are suitable for vertebral BMD assessment (no contrast agents) in clinical practice. Regular (e.g., monthly) stability tests using a calibration phantom could assure long term stability of at least 1 year.
Hypoparathyroidism: Similarities and differences between Western and Eastern countries
Backgroud Hypoparathyroidism (hypoPT) is characterized by acute and chronic complications due to insufficient parathyroid hormone (PTH) production or action. Several management guidelines have been developed, but mostly based on evidence from Western countries. Data from Eastern countries have not been systematically compared with those from Western countries. Methods Literatures regarding to the epidemiology, genetics, risk factors, clinical manifestations and therapies for hypoPT in Easten and Western countries, including China, South Korea, Japan, India, and USA, Canada, Italy, and etc., were searched through PubMed and CNKI. This review was officially endorsed by European Calcified Tissue Society (ECTS) board. Results Postoperative hypoPT is the major form of hypoPT in both Western and Eastern countries. The genetic profiles and clinical features of hypoPT are similar in Eastern and Western countries. The most commonly used medications in Eastern countries are calcium and native vitamin D or active vitamin D analogues, similar to their Western counterparts. While PTH replacement therapy is not available and approved to use in most Eastern countries. Conclusion Physicians and surgeons should follow the guidelines on the management of thyroid nodules, taking more care of protecting parathyroid glands during surgery. The cross-talk between East and West in the management of hypoPT should be continued. Direct comparisons of the management strategies in patients with hypoPT between Eastern and Wester countries regarding to the morbidity, mortality, quality of life, optimal dosage, efficacies and side-effects of conventional therapies or newer medications, as well as pharmacogenetics and pharmacoeconomics, would be valuable.