| 1. |
- Attauabi, Mohamed, et al.
(författare)
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Influence of Genetics, Immunity and the Microbiome on the Prognosis of Inflammatory Bowel Disease (IBD Prognosis Study) : the protocol for a Copenhagen IBD Inception Cohort Study
- 2022
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Ingår i: BMJ Open. - : BMJ Publishing Group Ltd. - 2044-6055. ; 12:6, s. e055779-e055779
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Inflammatory bowel diseases (IBD), encompassing Crohn's disease and ulcerative colitis, are chronic, inflammatory diseases of the gastrointestinal tract. We have initiated a Danish population-based inception cohort study aiming to investigate the underlying mechanisms for the heterogeneous course of IBD, including need for, and response to, treatment.Methods and analysis: IBD Prognosis Study is a prospective, population-based inception cohort study of unselected, newly diagnosed adult, adolescent and paediatric patients with IBD within the uptake area of Hvidovre University Hospital and Herlev University Hospital, Denmark, which covers approximately 1 050 000 inhabitants (~20% of the Danish population). The diagnosis of IBD will be according to the Porto diagnostic criteria in paediatric and adolescent patients or the Copenhagen diagnostic criteria in adult patients. All patients will be followed prospectively with regular clinical examinations including ileocolonoscopies, MRI of the small intestine, validated patient-reported measures and objective examinations with intestinal ultrasound. In addition, intestinal biopsies from ileocolonoscopies, stool, rectal swabs, saliva samples, swabs of the oral cavity and blood samples will be collected systematically for the analysis of biomarkers, microbiome and genetic profiles. Environmental factors and quality of life will be assessed using questionnaires and, when available, automatic registration of purchase data. The occurrence and course of extraintestinal manifestations will be evaluated by rheumatologists, dermatologists and dentists, and assessed by MR cholangiopancreatography, MR of the spine and sacroiliac joints, ultrasonography of peripheral joints and entheses, clinical oral examination, as well as panoramic radiograph of the jaws. Fibroscans and dual-energy X-ray absorptiometry scans will be performed to monitor occurrence and course of chronic liver diseases, osteopenia and osteoporosis.Ethics and dissemination: This study has been approved by Ethics Committee of the Capital Region of Denmark (approval number: H-20065831). Study results will be disseminated through publication in international scientific journals and presentation at (inter)national conferences.
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| 2. |
- Henriksen, Kim, et al.
(författare)
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Dissociation of Bone Resorption and Bone Formation in Adult Mice with a Non-Functional V-ATPase in Osteoclasts Leads to Increased Bone Strength
- 2011
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 6:11
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Tidskriftsartikel (refereegranskat)abstract
- Osteopetrosis caused by defective acid secretion by the osteoclast, is characterized by defective bone resorption, increased osteoclast numbers, while bone formation is normal or increased. In contrast the bones are of poor quality, despite this uncoupling of formation from resorption. To shed light on the effect of uncoupling in adult mice with respect to bone strength, we transplanted irradiated three-month old normal mice with hematopoietic stem cells from control or oc/oc mice, which have defective acid secretion, and followed them for 12 to 28 weeks. Engraftment levels were assessed by flow cytometry of peripheral blood. Serum samples were collected every six weeks for measurement of bone turnover markers. At termination bones were collected for mu CT and mechanical testing. An engraftment level of 98% was obtained. From week 6 until termination bone resorption was significantly reduced, while the osteoclast number was increased when comparing oc/oc to controls. Bone formation was elevated at week 6, normalized at week 12, and reduced onwards. mu CT and mechanical analyses of femurs and vertebrae showed increased bone volume and bone strength of cortical and trabecular bone. In conclusion, these data show that attenuation of acid secretion in adult mice leads to uncoupling and improves bone strength.
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| 3. |
- Flores Bjurström, Carmen, et al.
(författare)
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Osteoclasts are not crucial for hematopoietic stem cell maintenance in adult mice
- 2013
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Ingår i: Haematologica. - : Ferrata Storti Foundation (Haematologica). - 1592-8721 .- 0390-6078. ; 98:12, s. 1848-1855
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Tidskriftsartikel (refereegranskat)abstract
- The osteoclast is vital for establishment of normal hematopoiesis in the developing animal. However, its role for maintenance of hematopoiesis in adulthood is more controversial. To shed more light on this process, we transplanted hematopoietic stem cells from two osteopetrotic mouse models, with lack of osteoclasts or defective osteoclast function, to normal adult mice and examined the bone phenotype and hematopoiesis in the recipients. B6SJL mice were lethally irradiated and subsequently transplanted with oc/oc, Receptor Activator of Nuclear Factor Kappa B knockout or control fetal liver cells. Osteoclasts derived from the recipient animals were tested in vitro for osteoclastogenesis and resorptive function. Bone remodeling changes were assessed using biomarkers of bone tumrnover and micro-CT. Hematopoiesis was assessed by flow cytometry and colony formation, and hematopoietic stem cell function by secondary competitive transplantations and cell cycle analysis. After transplantation, a donor chimerism of 97-98% was obtained, and by 15 weeks mild osteopetrosis had developed in recipients of cells from osteopetrotic mice. There were no alterations in the number of bone marrow cells. Colony formation was slightly reduced in Receptor Activator of Nuclear Factor Kappa B knock-out recipients but unchanged in oc/oc recipients. Phenotypically, stem cells were marginally reduced in recipients of cells from osteopetrotic mice, but no significant difference was seen in cell cycle status and in competitive secondary transplantations all three groups performed equally well. Our results indicate that osteoclast function is not crucial for hematopoietic stem cell maintenance in adult mice.
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| 4. |
- Thudium, Christian, et al.
(författare)
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A Comparison of Osteoclast-Rich and Osteoclast-Poor Osteopetrosis in Adult Mice Sheds Light on the Role of the Osteoclast in Coupling Bone Resorption and Bone Formation
- 2014
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Ingår i: Calcified Tissue International. - : Springer Science and Business Media LLC. - 1432-0827 .- 0171-967X. ; 95:1, s. 83-93
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Tidskriftsartikel (refereegranskat)abstract
- Osteopetrosis due to lack of acid secretion by osteoclasts is characterized by abolished bone resorption, increased osteoclast numbers, but normal or even increased bone formation. In contrast, osteoclast-poor osteopetrosis appears to have less osteoblasts and reduced bone formation, indicating that osteoclasts are important for regulating osteoblast activity. To illuminate the role of the osteoclast in controlling bone remodeling, we transplanted irradiated skeletally mature 3-month old wild-type mice with hematopoietic stem cells (HSCs) to generate either an osteoclast-rich or osteoclast-poor adult osteopetrosis model. We used fetal liver HSCs from (1) oc/oc mice, (2) RANK KO mice, and (3) compared these to wt control cells. TRAP5b activity, a marker of osteoclast number and size, was increased in the oc/oc recipients, while a significant reduction was seen in the RANK KO recipients. In contrast, the bone resorption marker CTX-I was similarly decreased in both groups. Both oc/oc and Rank KO recipients developed a mild osteopetrotic phenotype. However, the osteoclast-rich oc/oc recipients showed higher trabecular bone volume (40 %), increased bone strength (66 %), and increased bone formation rate (54 %) in trabecular bone, while RANK KO recipients showed only minor trends compared to control recipients. We here show that maintaining non-resorbing osteoclasts, as opposed to reducing the osteoclasts, leads to increased bone formation, bone volume, and ultimately higher bone strength in vivo, which indicates that osteoclasts are sources of anabolic molecules for the osteoblasts.
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