@article{AltieriDiDatoModicaetal.2020, author = {Altieri, Barbara and Di Dato, Carla and Modica, Roberta and Bottiglieri, Filomena and Di Sarno, Antonella and Pittaway, James F.H. and Martini, Chiara and Faggiano, Antongiulio and Colao, Annamaria}, title = {Bone metabolism and vitamin D implication in gastroenteropancreatic neuroendocrine tumors}, series = {Nutrients}, volume = {12}, journal = {Nutrients}, number = {4}, issn = {2072-6643}, doi = {10.3390/nu12041021}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-203823}, year = {2020}, abstract = {Patients affected by gastroenteropancreatic-neuroendocrine tumors (GEP-NETs) have an increased risk of developing osteopenia and osteoporosis, as several factors impact on bone metabolism in these patients. In fact, besides the direct effect of bone metastasis, bone health can be affected by hormone hypersecretion (including serotonin, cortisol, and parathyroid hormone-related protein), specific microRNAs, nutritional status (which in turn could be affected by medical and surgical treatments), and vitamin D deficiency. In patients with multiple endocrine neoplasia type 1 (MEN1), a hereditary syndrome associated with NET occurrence, bone damage may carry other consequences. Osteoporosis may negatively impact on the quality of life of these patients and can increment the cost of medical care since these patients usually live with their disease for a long time. However, recommendations suggesting screening to assess bone health in GEP-NET patients are missing. The aim of this review is to critically analyze evidence on the mechanisms that could have a potential impact on bone health in patients affected by GEP-NET, focusing on vitamin D and its role in GEP-NET, as well as on factors associated with MEN1 that could have an impact on bone homeostasis.}, language = {en} } @article{FuchsHeiligMcDonoghetal.2020, author = {Fuchs, Konrad F. and Heilig, Philipp and McDonogh, Miriam and Boelch, Sebastian and Gbureck, Uwe and Meffert, Rainer H. and Hoelscher-Doht, Stefanie and Jordan, Martin C.}, title = {Cement-augmented screw fixation for calcaneal fracture treatment: a biomechanical study comparing two injectable bone substitutes}, series = {Journal of Orthopaedic Surgery and Research}, volume = {15}, journal = {Journal of Orthopaedic Surgery and Research}, doi = {10.1186/s13018-020-02009-6}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-230336}, year = {2020}, abstract = {Background The role of cement-augmented screw fixation for calcaneal fracture treatment remains unclear. Therefore, this study was performed to biomechanically analyze screw osteosynthesis by reinforcement with either a calcium phosphate (CP)-based or polymethylmethacrylate (PMMA)-based injectable bone cement. Methods A calcaneal fracture (Sanders type IIA) including a central cancellous bone defect was generated in 27 synthetic bones, and the specimens were assigned to 3 groups. The first group was fixed with four screws (3.5 mm and 6.5 mm), the second group with screws and CP-based cement (Graftys (R) QuickSet; Graftys, Aix-en-Provence, France), and the third group with screws and PMMA-based cement (Traumacem (TM) V+; DePuy Synthes, Warsaw, IN, USA). Biomechanical testing was conducted to analyze peak-to-peak displacement, total displacement, and stiffness in following a standardized protocol. Results The peak-to-peak displacement under a 200-N load was not significantly different among the groups; however, peak-to-peak displacement under a 600- and 1000-N load as well as total displacement exhibited better stability in PMMA-augmented screw osteosynthesis compared to screw fixation without augmentation. The stiffness of the construct was increased by both CP- and PMMA-based cements. Conclusion Addition of an injectable bone cement to screw osteosynthesis is able to increase fixation strength in a biomechanical calcaneal fracture model with synthetic bones. In such cases, PMMA-based cements are more effective than CP-based cements because of their inherently higher compressive strength. However, whether this high strength is required in the clinical setting for early weight-bearing remains controversial, and the non-degradable properties of PMMA might cause difficulties during subsequent interventions in younger patients.}, language = {en} } @article{HedrichHofmannPabliketal.2013, author = {Hedrich, Christian M. and Hofmann, Sigrun R. and Pablik, Jessica and Morbach, Henner and Girschick, Hermann J.}, title = {Autoinflammatory bone disorders with special focus on chronic recurrent multifocal osteomyelitis (CRMO)}, series = {Pediatric Rheumatology}, volume = {11}, journal = {Pediatric Rheumatology}, number = {47}, issn = {1546-0096}, doi = {10.1186/1546-0096-11-47}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-125694}, year = {2013}, abstract = {Sterile bone inflammation is the hallmark of autoinflammatory bone disorders, including chronic nonbacterial osteomyelitis (CNO) with its most severe form chronic recurrent multifocal osteomyelitis (CRMO). Autoinflammatory osteopathies are the result of a dysregulated innate immune system, resulting in immune cell infiltration of the bone and subsequent osteoclast differentiation and activation. Interestingly, autoinflammatory bone disorders are associated with inflammation of the skin and/or the intestine. In several monogenic autoinflammatory bone disorders mutations in disease-causing genes have been reported. However, regardless of recent developments, the molecular pathogenesis of CNO/CRMO remains unclear. Here, we discuss the clinical presentation and molecular pathophysiology of human autoinflammatory osteopathies and animal models with special focus on CNO/CRMO. Treatment options in monogenic autoinflammatory bone disorders and CRMO will be illustrated.}, language = {en} } @article{HedrichHofmannPabliketal.2013, author = {Hedrich, Christian M. and Hofmann, Sigrun R. and Pablik, Jessica and Morbach, Henner and Girschick, Hermann J.}, title = {Autoinflammatory bone disorders with special focus on chronic recurrent multifocal osteomyelitis (CRMO)}, series = {Pediatric Rheumatology}, volume = {11}, journal = {Pediatric Rheumatology}, number = {47}, doi = {10.1186/1546-0096-11-47}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-132456}, year = {2013}, abstract = {Sterile bone inflammation is the hallmark of autoinflammatory bone disorders, including chronic nonbacterial osteomyelitis (CNO) with its most severe form chronic recurrent multifocal osteomyelitis (CRMO). Autoinflammatory osteopathies are the result of a dysregulated innate immune system, resulting in immune cell infiltration of the bone and subsequent osteoclast differentiation and activation. Interestingly, autoinflammatory bone disorders are associated with inflammation of the skin and/or the intestine. In several monogenic autoinflammatory bone disorders mutations in disease-causing genes have been reported. However, regardless of recent developments, the molecular pathogenesis of CNO/CRMO remains unclear. Here, we discuss the clinical presentation and molecular pathophysiology of human autoinflammatory osteopathies and animal models with special focus on CNO/CRMO. Treatment options in monogenic autoinflammatory bone disorders and CRMO will be illustrated.}, language = {en} } @article{HerrmannEngelkeEbertetal.2020, author = {Herrmann, Marietta and Engelke, Klaus and Ebert, Regina and M{\"u}ller-Deubert, Sigrid and Rudert, Maximilian and Ziouti, Fani and Jundt, Franziska and Felsenberg, Dieter and Jakob, Franz}, title = {Interactions between muscle and bone — Where physics meets biology}, series = {Biomolecules}, volume = {10}, journal = {Biomolecules}, number = {3}, issn = {2218-273X}, doi = {10.3390/biom10030432}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-203399}, year = {2020}, abstract = {Muscle and bone interact via physical forces and secreted osteokines and myokines. Physical forces are generated through gravity, locomotion, exercise, and external devices. Cells sense mechanical strain via adhesion molecules and translate it into biochemical responses, modulating the basic mechanisms of cellular biology such as lineage commitment, tissue formation, and maturation. This may result in the initiation of bone formation, muscle hypertrophy, and the enhanced production of extracellular matrix constituents, adhesion molecules, and cytoskeletal elements. Bone and muscle mass, resistance to strain, and the stiffness of matrix, cells, and tissues are enhanced, influencing fracture resistance and muscle power. This propagates a dynamic and continuous reciprocity of physicochemical interaction. Secreted growth and differentiation factors are important effectors of mutual interaction. The acute effects of exercise induce the secretion of exosomes with cargo molecules that are capable of mediating the endocrine effects between muscle, bone, and the organism. Long-term changes induce adaptations of the respective tissue secretome that maintain adequate homeostatic conditions. Lessons from unloading, microgravity, and disuse teach us that gratuitous tissue is removed or reorganized while immobility and inflammation trigger muscle and bone marrow fatty infiltration and propagate degenerative diseases such as sarcopenia and osteoporosis. Ongoing research will certainly find new therapeutic targets for prevention and treatment.}, language = {en} } @article{KollmannsbergerKerschnitzkiReppetal.2017, author = {Kollmannsberger, Philip and Kerschnitzki, Michael and Repp, Felix and Wagermaier, Wolfgang and Weinkamer, Richard and Fratzl, Peter}, title = {The small world of osteocytes: connectomics of the lacuno-canalicular network in bone}, series = {New Journal of Physics}, volume = {19}, journal = {New Journal of Physics}, number = {073019}, doi = {10.1088/1367-2630/aa764b}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-170662}, year = {2017}, abstract = {Osteocytes and their cell processes reside in a large, interconnected network of voids pervading the mineralized bone matrix of most vertebrates. This osteocyte lacuno-canalicular network (OLCN) is believed to play important roles in mechanosensing, mineral homeostasis, and for the mechanical properties of bone. While the extracellular matrix structure of bone is extensively studied on ultrastructural and macroscopic scales, there is a lack of quantitative knowledge on how the cellular network is organized. Using a recently introduced imaging and quantification approach, we analyze the OLCN in different bone types from mouse and sheep that exhibit different degrees of structural organization not only of the cell network but also of the fibrous matrix deposited by the cells. We define a number of robust, quantitative measures that are derived from the theory of complex networks. These measures enable us to gain insights into how efficient the network is organized with regard to intercellular transport and communication. Our analysis shows that the cell network in regularly organized, slow-growing bone tissue from sheep is less connected, but more efficiently organized compared to irregular and fast-growing bone tissue from mice. On the level of statistical topological properties (edges per node, edge length and degree distribution), both network types are indistinguishable, highlighting that despite pronounced differences at the tissue level, the topological architecture of the osteocyte canalicular network at the subcellular level may be independent of species and bone type. Our results suggest a universal mechanism underlying the self-organization of individual cells into a large, interconnected network during bone formation and mineralization.}, language = {en} } @article{PaudelFusiSchmidt2021, author = {Paudel, Rupesh and Fusi, Lorenza and Schmidt, Marc}, title = {The MEK5/ERK5 pathway in health and disease}, series = {International Journal of Molecular Sciences}, volume = {22}, journal = {International Journal of Molecular Sciences}, number = {14}, issn = {1422-0067}, doi = {10.3390/ijms22147594}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-261638}, year = {2021}, abstract = {The MEK5/ERK5 mitogen-activated protein kinases (MAPK) cascade is a unique signaling module activated by both mitogens and stress stimuli, including cytokines, fluid shear stress, high osmolarity, and oxidative stress. Physiologically, it is mainly known as a mechanoreceptive pathway in the endothelium, where it transduces the various vasoprotective effects of laminar blood flow. However, it also maintains integrity in other tissues exposed to mechanical stress, including bone, cartilage, and muscle, where it exerts a key function as a survival and differentiation pathway. Beyond its diverse physiological roles, the MEK5/ERK5 pathway has also been implicated in various diseases, including cancer, where it has recently emerged as a major escape route, sustaining tumor cell survival and proliferation under drug stress. In addition, MEK5/ERK5 dysfunction may foster cardiovascular diseases such as atherosclerosis. Here, we highlight the importance of the MEK5/ERK5 pathway in health and disease, focusing on its role as a protective cascade in mechanical stress-exposed healthy tissues and its function as a therapy resistance pathway in cancers. We discuss the perspective of targeting this cascade for cancer treatment and weigh its chances and potential risks when considering its emerging role as a protective stress response pathway.}, language = {en} } @article{PereiraTrivanovićHerrmann2019, author = {Pereira, A. R. and Trivanović, D. and Herrmann, M.}, title = {Approaches to mimic the complexity of the skeletal mesenchymal stem/stromal cell niche in vitro}, series = {European Cells and Materials}, volume = {37}, journal = {European Cells and Materials}, issn = {1473-2262}, doi = {10.22203/eCM.v037a07}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-268823}, pages = {88-112}, year = {2019}, abstract = {Mesenchymal stem/stromal cells (MSCs) are an essential element of most modern tissue engineering and regenerative medicine approaches due to their multipotency and immunoregulatory functions. Despite the prospective value of MSCs for the clinics, the stem cells community is questioning their developmental origin, in vivo localization, identification, and regenerative potential after several years of far-reaching research in the field. Although several major progresses have been made in mimicking the complexity of the MSC niche in vitro, there is need for comprehensive studies of fundamental mechanisms triggered by microenvironmental cues before moving to regenerative medicine cell therapy applications. The present comprehensive review extensively discusses the microenvironmental cues that influence MSC phenotype and function in health and disease - including cellular, chemical and physical interactions. The most recent and relevant illustrative examples of novel bioengineering approaches to mimic biological, chemical, and mechanical microenvironmental signals present in the native MSC niche are summarized, with special emphasis on the forefront techniques to achieve bio-chemical complexity and dynamic cultures. In particular, the skeletal MSC niche and applications focusing on the bone regenerative potential of MSC are addressed. The aim of the review was to recognize the limitations of the current MSC niche in vitro models and to identify potential opportunities to fill the bridge between fundamental science and clinical application of MSCs.}, language = {en} } @article{PetritschGoltzHahnetal.2011, author = {Petritsch, Bernhard and Goltz, Jan Peter and Hahn, Dietbert and Wendel, Frank}, title = {Extensive craniocervical bone pneumatization}, series = {Diagnostic and Interventional Radiology}, volume = {17}, journal = {Diagnostic and Interventional Radiology}, number = {4}, doi = {10.4261/1305-3825.DIR.4299-11.2}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-139349}, pages = {308-310}, year = {2011}, abstract = {We report a case of extensive abnormal craniocervical bone pneumatization accidentally found in a patient without any history of trauma or surgery. The patient had only mild unspecific thoracic pain and bilateral paresthesia that did not correlate with computed tomography findings.}, language = {en} } @article{RathBrandlHilleretal.2014, author = {Rath, Subha N. and Brandl, Andreas and Hiller, Daniel and Hoppe, Alexander and Gbureck, Uwe and Horch, Raymund E. and Boccaccini, Aldo R. and Kneser, Ulrich}, title = {Bioactive Copper-Doped Glass Scaffolds Can Stimulate Endothelial Cells in Co-Culture in Combination with Mesenchymal Stem Cells}, series = {PLOS ONE}, volume = {9}, journal = {PLOS ONE}, number = {12}, issn = {1932-6203}, doi = {10.1371/journal.pone.0113319}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-114339}, year = {2014}, abstract = {Bioactive glass (BG) scaffolds are being investigated for bone tissue engineering applications because of their osteoconductive and angiogenic nature. However, to increase the in vivo performance of the scaffold, including enhancing the angiogenetic growth into the scaffolds, some researchers use different modifications of the scaffold including addition of inorganic ionic components to the basic BG composition. In this study, we investigated the in vitro biocompatibility and bioactivity of Cu2+-doped BG derived scaffolds in either BMSC (bone-marrow derived mesenchymal stem cells)-only culture or co-culture of BMSC and human dermal microvascular endothelial cells (HDMEC). In BMSC-only culture, cells were seeded either directly on the scaffolds (3D or direct culture) or were exposed to ionic dissolution products of the BG scaffolds, kept in permeable cell culture inserts (2D or indirect culture). Though we did not observe any direct osteoinduction of BMSCs by alkaline phosphatase (ALP) assay or by PCR, there was increased vascular endothelial growth factor (VEGF) expression, observed by PCR and ELISA assays. Additionally, the scaffolds showed no toxicity to BMSCs and there were healthy live cells found throughout the scaffold. To analyze further the reasons behind the increased VEGF expression and to exploit the benefits of the finding, we used the indirect method with HDMECs in culture plastic and Cu2+-doped BG scaffolds with or without BMSCs in cell culture inserts. There was clear observation of increased endothelial markers by both FACS analysis and acetylated LDL (acLDL) uptake assay. Only in presence of Cu2+-doped BG scaffolds with BMSCs, a high VEGF secretion was demonstrated by ELISA; and typical tubular structures were observed in culture plastics. We conclude that Cu2+-doped BG scaffolds release Cu2+, which in turn act on BMSCs to secrete VEGF. This result is of significance for the application of BG scaffolds in bone tissue engineering approaches.}, language = {en} }