| 1. |
- Cronin, O., et al.
(författare)
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Role of the Microbiome in Regulating Bone Metabolism and Susceptibility to Osteoporosis
- 2022
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Ingår i: Calcified Tissue International. - : Springer Science and Business Media LLC. - 0171-967X .- 1432-0827. ; 110:3, s. 273-284
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Tidskriftsartikel (refereegranskat)abstract
- The human microbiota functions at the interface between diet, medication-use, lifestyle, host immune development and health. It is therefore closely aligned with many of the recognised modifiable factors that influence bone mass accrual in the young, and bone maintenance and skeletal decline in older populations. While understanding of the relationship between micro-organisms and bone health is still in its infancy, two decades of broader microbiome research and discovery supports a role of the human gut microbiome in the regulation of bone metabolism and pathogenesis of osteoporosis as well as its prevention and treatment. Pre-clinical research has demonstrated biological interactions between the microbiome and bone metabolism. Furthermore, observational studies and randomized clinical trials have indicated that therapeutic manipulation of the microbiota by oral administration of probiotics may influence bone turnover and prevent bone loss in humans. In this paper, we summarize the content, discussion and conclusions of a workshop held by the Osteoporosis and Bone Research Academy of the Royal Osteoporosis Society in October, 2020. We provide a detailed review of the literature examining the relationship between the microbiota and bone health in animal models and in humans, as well as formulating the agenda for key research priorities required to advance this field. We also underscore the potential pitfalls in this research field that should be avoided and provide methodological recommendations to facilitate bridging the gap from promising concept to a potential cause and intervention target for osteoporosis.
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| 2. |
- Ohlsson, Claes, 1965, et al.
(författare)
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Osteomicrobiology: A New Cross-Disciplinary Research Field.
- 2018
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Ingår i: Calcified tissue international. - : Springer Science and Business Media LLC. - 1432-0827 .- 0171-967X. ; 102:4, s. 426-432
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Forskningsöversikt (refereegranskat)abstract
- The mutualistic interaction between the gut microbiota (GM) and its host profoundly shapes many aspects of our physiology. The composition and activity of the gut microbiota is modulated by environmental factors such as dietary habits and antibiotic treatments. In rodents, studies demonstrate that the GM is a crucial regulator of bone metabolism and that modulation of the GM composition by probiotic interventions can prevent castration-induced bone loss. Short-term colonization of germ-free mice with GM results in an activation of CD4+T cells, resulting in increased levels of pro-inflammatory cytokines in bone and thereby activation of osteoclastic bone resorption. Besides these immune-mediated effects on bone mass, the GM is involved in nutritional uptake and may, thereby, regulate overall body growth and bone sizes possibly mediated via altered IGF-I levels. We recently introduced a new term "osteomicrobiology" for the rapidly emerging research field of the role of the microbiota in bone health. This research field is aimed to bridge the gaps between bone physiology, gastroenterology, immunology, and microbiology. Future studies will determine if the GM is a novel therapeutic target for osteoporosis and if the GM composition might be used as a biomarker for fracture prediction.
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| 3. |
- Olson, Lisa E, et al.
(författare)
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The Role of GH/IGF-I-Mediated Mechanisms in Sex Differences in Cortical Bone Size in Mice.
- 2011
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Ingår i: Calcified tissue international. - : Springer Science and Business Media LLC. - 1432-0827 .- 0171-967X. ; 88:1, s. 1-8
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Tidskriftsartikel (refereegranskat)abstract
- Cortical bone dimensions are important determinants of bone strength. Gender differences in cortical bone size caused by greater periosteal expansion in males than in females during the pubertal growth spurt are well established both in humans and in experimental animal models. However, the mechanism by which gender influences cortical bone size is still a matter of investigation. The role of androgens and estrogen in pubertal bone growth has been examined in human disorders as well as animal models, such as gonadectomized or sex steroid receptor knockout mice. Based on the findings that growth hormone (GH) and insulin-like growth factor I (IGF-I) are major regulators of postnatal skeletal growth, we and others have predicted that sex hormones interact with the GH/IGF-I axis to regulate cortical bone size. However, studies conflict as to whether estrogen and androgens impact cortical bone size through the canonical pathway, through GH without IGF-I mediation, through IGF-I without GH stimulation, or independent of GH/IGF-I. We review recent data on the impact of sex steroids and components of the GH/IGF axis on sexual dimorphism in bone size. While the GH/IGF-I axis is a major player in regulating peak bone size, the relative contribution of GH/IGF-dependent mechanisms to sex differences in cortical bone size remains to be established.
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| 4. |
- Törnqvist, Anna E, et al.
(författare)
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Wnt16 Overexpression in Osteoblasts Increases the Subchondral Bone Mass but has no Impact on Osteoarthritis in Young Adult Female Mice
- 2020
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Ingår i: Calcified Tissue International. - : Springer Science and Business Media LLC. - 0171-967X .- 1432-0827. ; 107:1, s. 31-40
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Tidskriftsartikel (refereegranskat)abstract
- Epidemiological studies have shown that high bone mineral density (BMD) is associated with an increased risk of osteoarthritis (OA), but the causality of this relationship remains unclear. Both bone mass and OA have been associated with the WNT signaling pathway in genetic studies, there is thus an interest in studying molecular partners of the WNT signaling pathway and OA. Female mice overexpressing WNT16 in osteoblasts (Obl-Wnt16 mice) have an increased bone mass. We aimed to evaluate if the high bone mass in Obl-Wnt16 mice leads to a more severe experimental OA development than in WT control mice. We induced experimental OA in female Obl-Wnt16 and WT control mice by destabilizing the medial meniscus (DMM). The Obl-Wnt16 mice displayed thicker medial and lateral subchondral bone plates as well as increased subchondral trabecular bone volume/tissue volume (BV/TV) but un-altered thickness of articular cartilage compared to WT mice. After DMM surgery, there was no difference in OA severity in the articular cartilage in the knee joint between the Obl-Wnt16 and WT mice. Both the Obl-Wnt16 and WT mice developed osteophytes in the DMM-operated tibia to a similar extent. We conclude that although the Obl-Wnt16 female mice have a high subchondral bone mass due to increased WNT signaling, they do not exhibit a more severe OA phenotype than their WT controls. This demonstrates that high bone mass does not result in an increased risk of OA per se. © 2020, The Author(s).
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| 5. |
- Skrtic, Stanko, 1970, et al.
(författare)
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Cortisol decreases hepatocyte growth factor levels in human osteoblast-like cells.
- 2000
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Ingår i: Calcified tissue international. - 0171-967X. ; 66:2, s. 108-12
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Tidskriftsartikel (refereegranskat)abstract
- Osteoporosis is a well-known side effect of long-term treatment with glucocorticoids. The hepatocyte growth factor (HGF) receptor is expressed by human osteoclasts and osteoblasts, and mouse osteoblasts also express HGF, indicating that HGF may regulate bone metabolism. Because HGF could be a candidate factor in the local paracrine signaling between osteoblasts and osteoclasts in bone, we decided to study whether human osteoblasts secrete HGF and whether glucocorticoids regulate the expression of HGF. HGF was easily detectable in the culture medium from human osteoblast-like cells (hOB). The HGF protein released into the culture medium was increased with increasing confluency. Hydrocortisone decreased the amount of HGF released into the culture medium from hOB in a dose-dependent manner with a maximal effect at 10(-6) M. Time-course studies revealed that hydrocortisone decreased the amount of HGF released into the culture medium significantly after 16 hours of stimulation (65 +/- 2% of control culture). This effect of hydrocortisone was maximal after 24 hours of stimulation (52 +/- 8% of control culture). In conclusion, HGF is produced by primary cultured hOB cells. Furthermore, the amount of HGF released into the culture medium is decreased by glucocorticoids. The biological significance of this finding remains to be demonstrated.
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