Bone ReportsPub Date : 2024-01-11DOI: 10.1016/j.bonr.2024.101736
Bhanvi Ramchandani , Faryal Sardar Mirza
{"title":"Effectiveness of romosozumab in primary biliary cholangitis at half the recommended dose in an underweight patient","authors":"Bhanvi Ramchandani , Faryal Sardar Mirza","doi":"10.1016/j.bonr.2024.101736","DOIUrl":"https://doi.org/10.1016/j.bonr.2024.101736","url":null,"abstract":"<div><p>Romosozumab (RSB) is a monoclonal antibody to sclerostin that is approved for post-menopausal osteoporosis at high fracture risk. It is administered as a monthly 210 mg subcutaneous injection for 12 months. We report the response to half the standard dose of RSB in an underweight patient with severe osteoporosis and primary biliary cholangitis (PBC). Using half dose RSB (approximately 3 mg/kg RSB), she demonstrated significant improvement in lumbar spine BMD, paralleling the results of phase III trials. This case highlights the effectiveness of RSB in a patient with concomitant PBC, in addition to its effectiveness at half the recommended dose in an underweight patient.</p></div>","PeriodicalId":9043,"journal":{"name":"Bone Reports","volume":"20 ","pages":"Article 101736"},"PeriodicalIF":2.5,"publicationDate":"2024-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2352187224000032/pdfft?md5=2e88386e312f8b2e91b70067bc5ebc14&pid=1-s2.0-S2352187224000032-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139479846","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Bone ReportsPub Date : 2024-01-06DOI: 10.1016/j.bonr.2024.101735
Stuart J. Warden , Robyn K. Fuchs , Ziyue Liu , Katelynn R. Toloday , Rachel Surowiec , Sharon M. Moe
{"title":"Am I big boned? Bone length scaled reference data for HRpQCT measures of the radial and tibial diaphysis in White adults","authors":"Stuart J. Warden , Robyn K. Fuchs , Ziyue Liu , Katelynn R. Toloday , Rachel Surowiec , Sharon M. Moe","doi":"10.1016/j.bonr.2024.101735","DOIUrl":"10.1016/j.bonr.2024.101735","url":null,"abstract":"<div><p>Cross-sectional size of a long bone shaft influences its mechanical properties. We recently used high-resolution peripheral quantitative computed tomography (HRpQCT) to create reference data for size measures of the radial and tibial diaphyses. However, data did not take into account the impact of bone length. Human bone exhibits relatively isometric allometry whereby cross-sectional area increases proportionally with bone length. The consequence is that taller than average individuals will generally have larger z-scores for bone size outcomes when length is not considered. The goal of the current work was to develop a means of determining whether an individual's cross-sectional bone size is suitable for their bone length. HRpQCT scans performed at 30 % of bone length proximal from the distal end of the radius and tibia were acquired from 1034 White females (age = 18.0 to 85.3 y) and 392 White males (age = 18.4 to 83.6 y). Positive relationships were confirmed between bone length and cross-sectional areas and estimated mechanical properties. Scaling factors were calculated and used to scale HRpQCT outcomes to bone length. Centile curves were generated for both raw and bone length scaled HRpQCT data using the LMS approach. Excel-based calculators are provided to facilitate calculation of z-scores for both raw and bone length scaled HRpQCT outcomes. The raw z-scores indicate the magnitude that an individual's HRpQCT outcomes differ relative to expected sex- and age-specific values, with the scaled z-scores also considering bone length. The latter enables it to be determined whether an individual or population of interest has normal sized bones for their length, which may have implications for injury risk. In addition to providing a means of expressing HRpQCT bone size outcomes relative to bone length, the current study also provides centile curves for outcomes previously without reference data, including tissue mineral density and moments of inertia.</p></div>","PeriodicalId":9043,"journal":{"name":"Bone Reports","volume":"20 ","pages":"Article 101735"},"PeriodicalIF":2.5,"publicationDate":"2024-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2352187224000020/pdfft?md5=87f8bfe84a7da214b83e357c4948da4e&pid=1-s2.0-S2352187224000020-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139394371","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Characterization of the mechanical properties of the mouse Achilles tendon enthesis by microindentation. Effects of unloading and subsequent reloading","authors":"Claire Camy , Tilman Grünewald , Edouard Lamy , Flavy Roseren , Mathieu Caumes , Théo Fovet , Thomas Brioche , Cecile Genovesio , Angèle Chopard , Martine Pithioux , Sandrine Roffino","doi":"10.1016/j.bonr.2024.101734","DOIUrl":"10.1016/j.bonr.2024.101734","url":null,"abstract":"<div><p>The fibrocartilaginous tendon enthesis, i.e. the site where a tendon is attached to bone through a fibrocartilaginous tissue, is considered as a functionally graded interface. However, at local scale, a very limited number of studies have characterized micromechanical properties of this transitional tissue. The first goal of this work was to characterize the micromechanical properties of the mineralized part of the healthy Achilles tendon enthesis (ATE) through microindentation testing and to assess the degree of mineralization and of carbonation of mineral crystals by Raman spectroscopy. Since little is known about enthesis biological plasticity, our second objective was to examine the effects of unloading and reloading, using a mouse hindlimb-unloading model, on both the micromechanical properties and the mineral phase of the ATE. Elastic modulus, hardness, degree of mineralization, and degree of carbonation were assessed after 14 days of hindlimb suspension and again after a subsequent 6 days of reloading. The elastic modulus gradually increased along the mineralized part of the ATE from the tidemark to the subchondral bone, with the same trend being found for hardness. Whereas the degree of carbonation did not differ according to zone of measurement, the degree of mineralization increased by >70 % from tidemark to subchondral bone. Thus, the gradient in micromechanical properties is in part explained by a mineralization gradient. A 14-day unloading period did not appear to affect the gradient of micromechanical properties of the ATE, nor the degree of mineralization or carbonation. However, contrary to a short period of unloading, early return to normal mechanical load reduced the micromechanical properties gradient, regardless of carbonate-to-phosphate ratios, likely due to the more homogeneous degree of mineralization. These findings provide valuable data not only for tissue bioengineering, but also for musculoskeletal clinical studies and microgravity studies focusing on long-term space travel by astronauts.</p></div>","PeriodicalId":9043,"journal":{"name":"Bone Reports","volume":"20 ","pages":"Article 101734"},"PeriodicalIF":2.5,"publicationDate":"2024-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2352187224000019/pdfft?md5=610a00e8e0cbd935ae8670eb4e245a8a&pid=1-s2.0-S2352187224000019-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139394675","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Bone ReportsPub Date : 2024-01-02DOI: 10.1016/j.bonr.2023.101733
Pamela Rufus-Membere , Kara B. Anderson , Kara L. Holloway-Kew , Jacob W. Harland , Adolfo Diez-Perez , Mark A. Kotowicz , Julie A. Pasco
{"title":"The practicality of using bone impact microindentation in a population-based study of women: A Geelong-Osteoporosis Study","authors":"Pamela Rufus-Membere , Kara B. Anderson , Kara L. Holloway-Kew , Jacob W. Harland , Adolfo Diez-Perez , Mark A. Kotowicz , Julie A. Pasco","doi":"10.1016/j.bonr.2023.101733","DOIUrl":"10.1016/j.bonr.2023.101733","url":null,"abstract":"<div><p>Impact microindentation (IMI) is a minimally invasive technique that allows the assessment of bone material strength index (BMSi) in vivo, by measuring the depth of a micron-sized, spherical tip into cortical bone that is then indexed to the depth of the tip into a reference material. In this study, we aimed to assess the practicality of its application in 99 women aged 42-84 yr from the Geelong Osteoporosis Study. Impact microindentation was performed in the mid-shaft of the right tibia using the OsteoProbe. Immediately following measurement, each participant was requested to rate on a Visual Analogue Scale [0−10] the level of discomfort anticipated and experienced, any initial reluctance towards the measurement and whether they were willing to repeat the measurement. Of 99 potential participants who attended this assessment phase, 55 underwent IMI measurement. Reasons for non-measurement in 44 women were existing skin conditions (<em>n</em> = 8, 18.2 %) and excessive soft tissue around mid-tibial region (<em>n</em> = 32, 72.2 %). An additional four (9.1 %) participants did not provide any reasons for declining. For 55 participants who had underwent IMI, the expectation for pain when briefed about the procedure was low (2.28 ± 2.39), as was pain experienced during the measurement (0.72 ± 1.58). Participants were not reluctant to undergo the measurement (0.83 ± 1.67), and all indicated a willingness to repeat the measurement. Results of this study showed that the IMI technique is well tolerated and accepted by women participating in the Geelong Osteoporosis Study, suggesting that the technique shows promise in a research or clinical setting.</p></div>","PeriodicalId":9043,"journal":{"name":"Bone Reports","volume":"20 ","pages":"Article 101733"},"PeriodicalIF":2.5,"publicationDate":"2024-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2352187223000797/pdfft?md5=ce382801b3f6cefde8325f81ca01d850&pid=1-s2.0-S2352187223000797-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139394826","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Bone ReportsPub Date : 2023-12-22DOI: 10.1016/j.bonr.2023.101732
Ling Wang , Minghui Yang , Yufeng Ge , Yandong Liu , Gang Wang , Yongbin Su , Zhe Guo , Lu Yin , Pengju Huang , Jian Geng , Glen M. Blake , Bo He , Shiwen Zhu , Xiaoguang Cheng , Xinbao Wu , Hannu T. Aro , Annegreet Vlug , Klaus Engelke
{"title":"Risk prediction of second hip fracture by bone and muscle density of the hip varies with time after first hip fracture: A prospective cohort study","authors":"Ling Wang , Minghui Yang , Yufeng Ge , Yandong Liu , Gang Wang , Yongbin Su , Zhe Guo , Lu Yin , Pengju Huang , Jian Geng , Glen M. Blake , Bo He , Shiwen Zhu , Xiaoguang Cheng , Xinbao Wu , Hannu T. Aro , Annegreet Vlug , Klaus Engelke","doi":"10.1016/j.bonr.2023.101732","DOIUrl":"https://doi.org/10.1016/j.bonr.2023.101732","url":null,"abstract":"<div><h3>Purpose</h3><p>Predictors of ‘imminent’ risk of second hip fracture are unknown. The aims of the study were to explore strength of hip areal bone mineral density (aBMD), and muscle area and density for predicting second hip fracture at different time intervals.</p></div><div><h3>Methods</h3><p>Data of the Chinese Second Hip Fracture Evaluation were analyzed, a longitudinal study to evaluate the risk of second hip fracture (of the contralateral hip) by using CT images obtained immediately after first hip fracture. Muscle cross-sectional area and density were measured of the gluteus maximus (G.MaxM) and gluteus medius and minimus (G.Med/MinM) and aBMD of the proximal femur at the contralateral unfractured side. Patients were followed up for a median time of 4.5 years. Separate Cox models were used to predict second hip fracture risk at different time intervals after first event adjusted for age, sex, BMI and diabetes.</p></div><div><h3>Results</h3><p>The mean age of subjects with imminent (within 1st or 2nd year) second hip fracture was 79.80 ± 5.16 and 81.56 ± 3.64 years. In the 1st year after the first hip fracture, femoral neck (FN) aBMD predicted second hip fracture (HR 5.88; 95 % CI, 1.32–26.09). In the remaining years of follow-up after 2nd year, muscle density predicted second hip fracture (G.MaxM HR 2.13; 95 % CI, 1.25–3.65,G.Med/MinM HR 2.10; 95 % CI, 1.32–3.34).</p></div><div><h3>Conclusions</h3><p>Our results show that femoral neck aBMD is an important predictor for second hip fracture within the first year and therefore suggest supports the importance concept of early and rapid-acting bone-active drugs to increase hip BMD. In addition, the importance of muscle density predicting second hip fracture after the second year suggest post hip fracture rehabilitation and exercise programs could also be important to reduce muscle fatty infiltration.</p></div>","PeriodicalId":9043,"journal":{"name":"Bone Reports","volume":"20 ","pages":"Article 101732"},"PeriodicalIF":2.5,"publicationDate":"2023-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2352187223000785/pdfft?md5=70cb51cfbbfba363b76604e598345987&pid=1-s2.0-S2352187223000785-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139033824","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"X-linked hypophosphatemia due to a de novo novel splice-site variant in a 7-year-old girl with scaphocephaly, Chiari syndrome type I and syringomyelia","authors":"Maria Fourikou , Aristea Karipiadou , Athina Ververi , Parthena Savvidou , Nikolaos Laliotis , Vassilios Tsitouras , Stella Stabouli , Emmanuel Roilides , Konstantinos Kollios","doi":"10.1016/j.bonr.2023.101731","DOIUrl":"10.1016/j.bonr.2023.101731","url":null,"abstract":"<div><p>X-linked hypophosphatemia (XLH) is a rare X-linked dominant inherited disorder caused by loss-of-function variants in the PHEX gene and characterized by renal phosphate wasting, hypophosphatemia, abnormal vitamin D metabolism, growth retardation and lower limb deformities. We describe a case of XLH-rickets in a 7-year-old girl with scaphocephaly, Chiari syndrome type I and syringomyelia, with a de novo non-canonical splice variant (c.1080-3C > G) in intron 9 of the PHEX gene, that has not been previously described.</p></div>","PeriodicalId":9043,"journal":{"name":"Bone Reports","volume":"20 ","pages":"Article 101731"},"PeriodicalIF":2.5,"publicationDate":"2023-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2352187223000773/pdfft?md5=bbe478b2b0c056ef802fec2bd9c51611&pid=1-s2.0-S2352187223000773-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138993258","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Bone ReportsPub Date : 2023-12-04DOI: 10.1016/j.bonr.2023.101730
Kaleen N. Hayes , Suzanne M. Cadarette , Andrea M. Burden
{"title":"Methodological guidance for the use of real-world data to measure exposure and utilization patterns of osteoporosis medications","authors":"Kaleen N. Hayes , Suzanne M. Cadarette , Andrea M. Burden","doi":"10.1016/j.bonr.2023.101730","DOIUrl":"10.1016/j.bonr.2023.101730","url":null,"abstract":"<div><p>Observational studies of osteoporosis medications can provide critical real-world evidence (RWE) that fills knowledge gaps left by clinical trials. However, careful consideration of study design is needed to yield reliable estimates of association. In particular, obtaining valid measurements of exposure to osteoporosis medications from real-world data (RWD) sources is complicated due to different medication classes, formulations, and routes of administration, each with different pharmacology. Extended half-lives of bisphosphonates and extended dosing of denosumab and zoledronic acid require particular attention. In addition, prescribing patterns and medication taking behavior often result in gaps in therapy, switching, and concomitant use of osteoporosis therapies. In this review, we present important considerations and provide specialized guidance for measuring osteoporosis drug exposures in RWD. First, we compare different sources of RWD used for osteoporosis drug studies and provide guidance on identifying osteoporosis medication use in these data sources. Next, we provide an overview of osteoporosis pharmacology and how it can influence decisions on exposure measurement within RWD. Finally, we present considerations for the measurement of osteoporosis medication exposure, adherence, switching, long-term exposures, and drug holidays using RWD. Ultimately, a thorough understanding of the differences in RWD sources and the pharmacology of osteoporosis medications is essential to obtain valid estimates of the relationship between osteoporosis medications and outcomes, such as fractures, but also to improve the critical appraisal of published studies.</p></div>","PeriodicalId":9043,"journal":{"name":"Bone Reports","volume":"20 ","pages":"Article 101730"},"PeriodicalIF":2.5,"publicationDate":"2023-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2352187223000761/pdfft?md5=17b3414fdbaced4a943e3deed4df1739&pid=1-s2.0-S2352187223000761-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138617789","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Bone ReportsPub Date : 2023-12-01DOI: 10.1016/j.bonr.2023.101686
Lena Steppe , Michael Megafu , Miriam E.A. Tschaffon-Müller , Anita Ignatius , Melanie Haffner-Luntzer
{"title":"Fracture healing research: Recent insights","authors":"Lena Steppe , Michael Megafu , Miriam E.A. Tschaffon-Müller , Anita Ignatius , Melanie Haffner-Luntzer","doi":"10.1016/j.bonr.2023.101686","DOIUrl":"10.1016/j.bonr.2023.101686","url":null,"abstract":"<div><p>Bone has the rare capability of scarless regeneration that enables the complete restoration of the injured bone area. In recent decades, promising new technologies have emerged from basic, translational and clinical research for fracture treatment; however, 5–10 % of all bone fractures still fail to heal successfully or heal in a delayed manner. Several comorbidities and risk factors have been identified which impair bone healing and might lead to delayed bone union or non-union. Therefore, a considerable amount of research has been conducted to elucidate molecular mechanisms of successful and delayed fracture healing to gain further insights into this complex process. One focus of recent research is to investigate the complex interactions of different cell types and the action of progenitor cells during the healing process. Of particular interest is also the identification of patient-specific comorbidities and how these affect fracture healing. In this review, we discuss the recent knowledge about progenitor cells for long bone repair and the influence of comorbidities such as diabetes, postmenopausal osteoporosis, and chronic stress on the healing process. The topic selection for this review was made based on the presented studies at the 2022 annual meeting of the European Calcified Tissue Society (ECTS) in Helsinki.</p></div>","PeriodicalId":9043,"journal":{"name":"Bone Reports","volume":"19 ","pages":"Article 101686"},"PeriodicalIF":2.5,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2352187223000347/pdfft?md5=8f5def2fcdf51a5cad059afc200b8c67&pid=1-s2.0-S2352187223000347-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44142501","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Bone ReportsPub Date : 2023-12-01DOI: 10.1016/j.bonr.2023.101678
Hicham Drissi , Hanna Taipaleenmäki , Christian Jorgensen
{"title":"Redefining stem cells through their use in musculoskeletal tissue preservation, regeneration, and cancer metastases to bone","authors":"Hicham Drissi , Hanna Taipaleenmäki , Christian Jorgensen","doi":"10.1016/j.bonr.2023.101678","DOIUrl":"10.1016/j.bonr.2023.101678","url":null,"abstract":"","PeriodicalId":9043,"journal":{"name":"Bone Reports","volume":"19 ","pages":"Article 101678"},"PeriodicalIF":2.5,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2352187223000268/pdfft?md5=458030d8d27718d509b55ea0cf8a99c6&pid=1-s2.0-S2352187223000268-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47024617","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Bone ReportsPub Date : 2023-12-01DOI: 10.1016/j.bonr.2023.101664
Adriana Marques-Carvalho , Ha-Neui Kim , Maria Almeida
{"title":"The role of reactive oxygen species in bone cell physiology and pathophysiology","authors":"Adriana Marques-Carvalho , Ha-Neui Kim , Maria Almeida","doi":"10.1016/j.bonr.2023.101664","DOIUrl":"10.1016/j.bonr.2023.101664","url":null,"abstract":"<div><p>Hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>), superoxide anion radical (O<sub>2</sub><sup>−</sup><img>), and other forms of reactive oxygen species (ROS) are produced by the vast majority of mammalian cells and can contribute both to cellular homeostasis and dysfunction. The NADPH oxidases (NOX) enzymes and the mitochondria electron transport chain (ETC) produce most of the cellular ROS. Multiple antioxidant systems prevent the accumulation of excessive amounts of ROS which cause damage to all cellular macromolecules. Many studies have examined the contribution of ROS to different bone cell types and to skeletal physiology and pathophysiology. Here, we discuss the role of H<sub>2</sub>O<sub>2</sub> and O<sub>2</sub><sup>−</sup><img> and their major enzymatic sources in osteoclasts and osteoblasts, the fundamentally different ways via which these cell types utilize mitochondrial derived H<sub>2</sub>O<sub>2</sub> for differentiation and function, and the molecular mechanisms that impact and are altered by ROS in these cells. Particular emphasis is placed on evidence obtained from mouse models describing the contribution of different sources of ROS or antioxidant enzymes to bone resorption and formation. Findings from studies using pharmacological or genetically modified mouse models indicate that an increase in H<sub>2</sub>O<sub>2</sub> and perhaps other ROS contribute to the loss of bone mass with aging and estrogen deficiency, the two most important causes of osteoporosis and increased fracture risk in humans.</p></div>","PeriodicalId":9043,"journal":{"name":"Bone Reports","volume":"19 ","pages":"Article 101664"},"PeriodicalIF":2.5,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2352187223000128/pdfft?md5=f5c1ba3420929d1ef183bd853ec71610&pid=1-s2.0-S2352187223000128-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48941299","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}