@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{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{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} } @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} } @phdthesis{Ruecker2019, author = {R{\"u}cker, Christoph}, title = {Development of a prevascularized bone implant}, doi = {10.25972/OPUS-17886}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-178869}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {The skeletal system forms the mechanical structure of the body and consists of bone, which is hard connective tissue. The tasks the skeleton and bones take over are of mechanical, metabolic and synthetic nature. Lastly, bones enable the production of blood cells by housing the bone marrow. Bone has a scarless self-healing capacity to a certain degree. Injuries exceeding this capacity caused by trauma, surgical removal of infected or tumoral bone or as a result from treatment-related osteonecrosis, will not heal. Critical size bone defects that will not heal by themselves are still object of comprehensive clinical investigation. The conventional treatments often result in therapies including burdening methods as for example the harvesting of autologous bone material. The aim of this thesis was the creation of a prevascularized bone implant employing minimally invasive methods in order to minimize inconvenience for patients and surgical site morbidity. The basis for the implant was a decellularized, naturally derived vascular scaffold (BioVaSc-TERM®) providing functional vessel structures after reseeding with autologous endothelial cells. The bone compartment was built by the combination of the aforementioned scaffold with synthetic β-tricalcium phosphate. In vitro culture for tissue maturation was performed using bioreactor technology before the testing of the regenerative potential of the implant in large animal experiments in sheep. A tibia defect was treated without the anastomosis of the implant's innate vasculature to the host's circulatory system and in a second study, with anastomosis of the vessel system in a mandibular defect. While the non-anastomosed implant revealed a mostly osteoconductive effect, the implants that were anastomosed achieved formation of bony islands evenly distributed over the defect. In order to prepare preconditions for a rapid approval of an implant making use of this vascularization strategy, the manufacturing of the BioVaSc-TERM® as vascularizing scaffold was adjusted to GMP requirements.}, subject = {Tissue Engineering}, language = {en} } @article{StratosRinasSchroepferetal.2023, author = {Stratos, Ioannis and Rinas, Ingmar and Schr{\"o}pfer, Konrad and Hink, Katharina and Herlyn, Philipp and B{\"a}umler, Mario and Histing, Tina and Bruhn, Sven and M{\"u}ller-Hilke, Brigitte and Menger, Michael D. and Vollmar, Brigitte and Mittlmeier, Thomas}, title = {Effects on bone and muscle upon treadmill interval training in hypogonadal male rats}, series = {Biomedicines}, volume = {11}, journal = {Biomedicines}, number = {5}, issn = {2227-9059}, doi = {10.3390/biomedicines11051370}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-319266}, year = {2023}, abstract = {Testosterone deficiency in males is linked to various pathological conditions, including muscle and bone loss. This study evaluated the potential of different training modalities to counteract these losses in hypogonadal male rats. A total of 54 male Wistar rats underwent either castration (ORX, n = 18) or sham castration (n = 18), with 18 castrated rats engaging in uphill, level, or downhill interval treadmill training. Analyses were conducted at 4, 8, and 12 weeks postsurgery. Muscle force of the soleus muscle, muscle tissue samples, and bone characteristics were analyzed. No significant differences were observed in cortical bone characteristics. Castrated rats experienced decreased trabecular bone mineral density compared to sham-operated rats. However, 12 weeks of training increased trabecular bone mineral density, with no significant differences among groups. Muscle force measurements revealed decreased tetanic force in castrated rats at week 12, while uphill and downhill interval training restored force to sham group levels and led to muscle hypertrophy compared to ORX animals. Linear regression analyses showed a positive correlation between bone biomechanical characteristics and muscle force. The findings suggest that running exercise can prevent bone loss in osteoporosis, with similar bone restoration effects observed across different training modalities.}, language = {en} } @phdthesis{Koschitzki2020, author = {Koschitzki, Kim Christine Cornelia}, title = {Evaluation of preclinical animal models in bone tissue engineering and their success in clinical translation}, doi = {10.25972/OPUS-20759}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-207593}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2020}, abstract = {Autologous bone still represents today's gold standard for the treatment of critical size bone defects and fracture non-unions despite associated disadvantages regarding limitations in availability, donor site morbidity, costs and efficacy. Bone tissue engineered constructs would present a promising alternative to currently available treatments. However, research on preclinical animal studies still fails to provide clinical applicable results able to allow the replacement of currently applied methods. It seems that the idea of bone tissue engineering, which has now been integral part of academic studies for over 30 years, got somehow stuck at an intermediate level, in between intense preclinical research and striven stages of initial clinical trial phases. A clear discrepancy exists between the number of studies with preclinical animal models for bone tissue engineering and the number of clinically approved bone tissue engineered constructs available to patients. The aim of this thesis was hence to evaluate preclinical animal models for bone tissue engineering as well as the perception of scientists and clinicians towards these models. Moreover, the general role of bone tissue engineering and its clinical need assessed by scientists and surgeons was investigated. A survey was conducted questioning both scientific and clinical opinions on currently available study designs and researchers' satisfaction with preclinical animal models. Additionally, a literature research was conducted, resulting in 167 papers from the last 10 years that report current designs of preclinical orthotopic animal studies in bone tissue engineering. Thereby, the focus lied on the description of the models regarding animal species, strain, age, gender and defect design. The outcome of the literature search was evaluated and compared to the outcome obtained from the survey. The survey data revealed that both scientists and surgeons generally remain positive about the future role of bone tissue engineering and its step to clinical translation, at least in the distant future, where it then might replace the current gold standard, autologous bone. Moreover, most of the participants considered preclinical animal models as relevant and well developed but the results as not yet realizable in the clinics. Surgeons thereby demonstrated a slightly more optimistic perception of currently conducted research with animal models compared to scientists. However, a rather inconsistent description of present preclinical study designs could be discerned when evaluating the reported study designs in the survey and the papers of the literature search. Indeed, defining an appropriate animal species, strain, age, gender, observation time, observation method and surgical design often depends on different indications and research questions and represents a highly challenging task for the establishment of a preclinical animal model. The existing lack of valid guidelines for preclinical testing of bone tissue engineering leads hence to a lack of well standardized preclinical animal models. Moreover, still existing knowledge gaps regarding aspects that affect the process of fracture healing, such as vascularization or immunological aspects, were found to hinder clinical translation of bone tissue engineered constructs. Using literature review and survey, this thesis points out critical issues that need to be addressed to allow clinical translation of bone tissue engineered constructs. It can be concluded that currently existing study designs with preclinical animal models cannot live up to the claim of providing suitable results for clinical implementation. The here presented comprehensive summary of currently used preclinical animal models for bone tissue engineering reveals a missing consensus on the usage of models such as an apparent lack of reporting and standardization regarding the study designs described in both papers from the literature review and the survey. It thereby indicates a crucial need to improve preclinical animal models in order to allow clinical translation. Despite the fact that participants of the survey generally revealed a positive perception towards the use of bone tissue engineered constructs and affirmed the clinical need for such novel designs, the missing standardization constitutes a main weak point for the provision of reliable study outcome and the translational success of the models. The optimization of reproducibility and reliability, as well as the further understanding of ongoing mechanisms in bone healing in order to develop effective tissue engineered constructs, need to form the basis of all study designs. The study outcomes might then fulfill the requirements of maybe today's and hopefully tomorrow's aging population.}, 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} }