Narrative Review of Effects of Glucagon-Like Peptide-1 Receptor Agonists on Bone Health in People Living with Obesity.

Glucagon-like peptide-1 Receptor agonists (GLP-1Ras) such as liraglutide and semaglutide have been recently approved as medications for chronic weight management in people living with obesity (PwO); GLP-1 may enhance bone metabolism and improve bone quality. However, the effects of GLP-1Ras on skeletal health remain to be determined and that's the purpose of this narrative review. Nevertheless, bone consequences of intentional weight loss interventions in PwO are well known: (i) significant weight loss induced by caloric restriction and bariatric surgery results in accelerated bone turnover and bone loss, and (ii) unlike caloric restriction interventions, PwO experience a substantial deterioration in bone microarchitecture and strength associated with an increased risk of fracture after bariatric surgery especially malabsorptive procedures. Liraglutide seems to have a positive effect on bone material properties despite significant weight loss in several rodent models. However, most of positive effects on bone mineral density and microarchitecture were observed at concentration much higher than approved for obesity care in humans. No data have been reported in preclinical models with semaglutide. The current evidence of the effects of GLP-1Ra on bone health in PwO is limited. Indeed, studies on the use of GLP-1Ra mostly included patients with diabetes who were administered a dose used in this condition, did not have adequate bone parameters as primary endpoints, and had short follow-up periods. Further studies are needed to investigate the bone impact of GLP-1Ra, dual- and triple-receptor agonists for GLP-1, glucose-dependent insulin releasing polypeptide (GIP), and glucagon in PwO.

Osteoporosis and Bone Marrow Adipose Tissue.

PURPOSE OF REVIEW: This review focuses on the recent findings regarding bone marrow adipose tissue (BMAT) concerning bone health. We summarize the variations in BMAT in relation to age, sex, and skeletal sites, and provide an update on noninvasive imaging techniques to quantify human BMAT. Next, we discuss the role of BMAT in patients with osteoporosis and interventions that affect BMAT. RECENT FINDINGS: There are wide individual variations with region-specific fluctuation and age- and gender-specific differences in BMAT content and composition. The Bone Marrow Adiposity Society (BMAS) recommendations aim to standardize imaging protocols to increase comparability across studies and sites. Water-fat imaging (WFI) seems an accurate and efficient alternative for spectroscopy (1H-MRS). Most studies indicate that greater BMAT is associated with lower bone mineral density (BMD) and a higher prevalence of vertebral fractures. The proton density fat fraction (PDFF) and changes in lipid composition have been associated with an increased risk of fractures independently of BMD. Therefore, PDFF and lipid composition could potentially be future imaging biomarkers for assessing fracture risk. Evidence of the inhibitory effect of osteoporosis treatments on BMAT is still limited to a few randomized controlled trials. Moreover, results from the FRAME biopsy sub-study highlight contradictory findings on the effect of the sclerostin antibody romosozumab on BMAT. Further understanding of the role(s) of BMAT will provide insight into the pathogenesis of osteoporosis and may lead to targeted preventive and therapeutic strategies.

Relationships between Circulating Sclerostin, Bone Marrow Adiposity, Other Adipose Deposits and Lean Mass in Post-Menopausal Women.

Sclerostin is a Wnt signaling pathway inhibitor that negatively regulates bone formation. Bone-marrow-derived stromal cell (BMSC) differentiation is influenced by the Wnt pathway, leading to the hypothesis that higher levels of sclerostin might be associated with an increase in bone marrow adiposity (BMA). The main purpose of this study was to determine whether a relationship exists between circulating sclerostin and BMA in post-menopausal women with and without fragility fractures. The relationships between circulating sclerostin and body composition parameters were then examined. The outcomes measures included vertebral and hip proton density fat fraction (PDFF) using the water fat imaging (WFI) MRI method; DXA scans; and laboratory measurements, including serum sclerostin. In 199 participants, no significant correlations were found between serum sclerostin and PDFF. In both groups, serum sclerostin was correlated positively with bone mineral density (R = 0.27 to 0.56) and negatively with renal function (R = -0.22 to -0.29). Serum sclerostin correlated negatively with visceral adiposity in both groups (R = -0.24 to -0.32). Serum sclerostin correlated negatively with total body fat (R = -0.47) and appendicular lean mass (R = -0.26) in the fracture group, but not in the controls. No evidence of a relationship between serum sclerostin and BMA was found. However, serum sclerostin was negatively correlated with body composition components, such as visceral adiposity, total body fat and appendicular lean mass.

Bariatric Surgery and Osteoporosis.

It has been increasingly acknowledged that bariatric surgery adversely affects skeletal health. After bariatric surgery, the extent of high-turnover bone loss is much greater than what would be expected in the absence of a severe skeletal insult. Patients also experience a significant deterioration in bone microarchitecture and strength. There is now a growing body of evidence that suggests an association between bariatric surgery and higher fracture risk. Although the mechanisms underlying the high-turnover bone loss and increase in fracture risk after bariatric surgery are not fully understood, many factors seem to be involved. The usual suspects are nutritional factors and mechanical unloading, and the roles of gut hormones, adipokines, and bone marrow adiposity should be investigated further. Roux-en-Y gastric bypass (RYGB) was once the most commonly performed bariatric procedure worldwide, but sleeve gastrectomy (SG) has now become the predominant bariatric procedure. Accumulating evidence suggests that RYGB is associated with a greater reduction in BMD, a greater increase in markers of bone turnover, and a higher risk of fracture than SG. These findings should be taken into consideration in determining the most appropriate bariatric procedure for patients, especially those at higher fracture risk. Before and after all bariatric procedures, sufficient calcium, vitamin D and protein intake, and adequate physical activity, are needed to counteract negative impacts on bone. There are no studies to date that have evaluated the effect of osteoporosis treatment on high-turnover bone loss after bariatric surgery. However, in patients with a diagnosis of osteoporosis, anti-resorptive agents may be considered.

Decreased monocyte calcium sensing receptor expression in patients with chronic kidney disease is associated with impaired monocyte ability to reduce vascular calcification.

In chronic kidney disease (CKD), calcium-sensing receptor (CaSR) expression and function have been extensively studied in parathyroid tissue and vascular tissues. To examine whether similar changes occurred in other tissues, we measured total and surface CaSR expression in monocytes of patients with various stages of CKD and healthy volunteers respectively in cross-sectional studies. We further explored in vitro the impact of uremic serum on CaSR expression in monocytes (U937 and THP-1 cell lines), and whether human peripheral blood mononuclear cells or U937 and THP-1 monocytes might modify vascular calcium deposition in rat carotid arteries in vitro. CKD was associated with a decrease in peripheral blood mononuclear cell CaSR expression both in total and at the monocyte surface alone (43% and 34%, respectively in CKD stages 4-5). This decrease was associated with a reduction in the ability of monocytes to inhibit vascular calcification in vitro. Pretreatment with the calcimimetic NPSR568 of peripheral blood mononuclear cells isolated from patients with CKD significantly improved monocyte capacity to reduce carotid calcification in vitro. The fewer peripheral blood mononuclear cells expressing cell surface CaSR, the more calcimimetic treatment enhanced the decrease of carotid calcium content. Thus, we demonstrate that monocyte CaSR expression is decreased in patients with CKD and provide in vitro evidence for a potential role of this decrease in the promotion of vascular calcification. Hence, targeting this alteration or following monocyte CaSR expression as an accessible marker might represent a promising therapeutic strategy in CKD-associated arterial calcification.

Bone Samples Extracted from Embalmed Subjects Are Not Appropriate for the Assessment of Bone Quality at the Molecular Level Using Raman Spectroscopy.

Bone samples extracted from embalmed cadavers are commonly used as controls in the study of bone. The effects of embalmment on the molecular composition of bone are unknown. The objective of this study was to determine the effect of embalmment on the molecular composition and structure of bone, as evaluated by Raman spectroscopy. Bone samples of femoral heads from five embalmed donors and five fresh-frozen donors were compared using Raman microspectroscopy with DuoScan technology. Physicochemical parameters simultaneously describing the organic and mineral phases of bone were compared using the Mann-Whitney U test. Partial least squares discriminant analysis (PLS-DA) was used to determine specific Raman spectral features of each group. Study of the mineral phase showed a 15% reduction of the mineral-to-matrix ratio (p < 0.001), an 8% decrease of type B carbonate substitution (p < 0.001), and a 2% increase in crystallinity (p < 0.001) in the embalmed donors group compared to those of the fresh donors group. Regarding the organic phase of bone, the hydroxyproline-to-proline ratio was increased by 18% in the embalmed group (p < 0.001), with no variation in both the relative proteoglycan content (GAG/CH3) (p = 0.08) and collagen maturity (p = 0.57). PLS-DA showed that the embalmed group was characterized mainly by peaks assigned to hydroxyproline, lipids, and collagen. Embalmment induces significant modifications of the molecular composition of bone. Bone samples from embalmed subjects should be avoided as controls for Raman spectroscopy studies. Preservation procedures performed prior to bone sampling should be reported in studies using human cadaver samples.

Bone Microarchitecture in Men and Women with Diabetes: The Importance of Cortical Porosity.

High-resolution peripheral quantitative computed tomography (HR-pQCT) captures novel aspects of bone geometry, volumetric bone mineral density and offers the ability to measure bone microarchitecture, but data relating measures obtained from this technique to diabetic status are inconsistent in women and lacking in men. Here, we report an analysis from the Hertfordshire Cohort Study, where we were able to study associations between bone microarchitecture from HR-pQCT of distal radius and distal tibia in 332 participants (177 men and 155 women) aged 72.1-81.4 years with or without diabetes mellitus (DM); n = 29 (18 men and 11 women) and n = 303, respectively. Statistical analyses were performed separately for women and men. The mean (SD) age of participants was 76.4 (2.6) and 76.1 (2.5) years in women and men, respectively. Participants with DM differed significantly in terms of weight in both women (70.4 ± 12.3 vs. 80.3 ± 18.3 kg; p = 0.015) and men (81.7 ± 11.4 vs. 92.8 ± 16.3 kg; p < 0.001) but no differences were found in height, smoking status, alcohol intake, social class and physical activity among women or men. Analyses in women revealed that cortical pore volume (Ct.Po.V) was higher in participants with DM and close to statistical significance for cortical porosity (Ct.Po) (ß = 0.76 [0.12, 1.41] z-score, p = 0.020 and ß = 0.62 [-0.02, 1.27] z-score, p = 0.059, respectively) at the distal radius. Adjustment for weight did not materially affect the relationship described for Ct.Po.V (ß = 0.74 [0.09, 1.39], p = 0.027) and Ct.Po (ß = 0.65 [-0.01, 1.30], p = 0.053) at the distal radius. After adjustment for weight, analyses in men revealed that Ct.Po and Ct.Po.V were higher in participants with DM (ß = 0.57 [0.09, 1.06] z-score, p = 0.021 and ß = 0.48 [0.01, 0.95] z-score, p = 0.044, respectively) at the distal tibia. Analyses of distal radial and tibial trabecular bone parameters according to diabetic status revealed no significant differences among men or women after adjustment for weight. We found higher cortical porosity and cortical pore volume at the distal tibia in men with DM and higher cortical pore volume at the distal radius in women with a non-significant tendency for higher cortical porosity. The results of our study suggest that deficits in cortical bone exist both in older men and women with DM.

Morbimortality in adult patients with septic arthritis: a three-year hospital-based study.

BACKGROUND: The objective of this ambispective study was to determine outcomes and associated factors for adult patients with confirmed septic arthritis (SA). METHODS: All adult patients admitted to Amiens University Hospital between November 2010 and December 2013 with confirmed SA were included in the study. Patients with prosthetic joint infections were excluded. A statistical analysis was performed in order to identify risk factors associated with a poor outcome (including mortality directly attributable to SA). RESULTS: A total of 109 patients (mean ± SD age: 60.1 ± 20.1; 74 male/35 females) were diagnosed with SA during the study period. The most commonly involved sites were the small joints (n = 34, 31.2 %) and the knee (n = 25, 22.9 %). The most frequent concomitant conditions were cardiovascular disease (n = 45, 41.3 %) and rheumatic disease (n = 39, 35.8 %). One hundred patients (91.7 %) had a positive microbiological culture test, with Staphylococcus aureus as the most commonly detected pathogen (n = 59, 54.1 %). Mortality directly attributable to SA was relatively infrequent (n = 6, 5.6 %) and occurred soon after the onset of SA (median [range]: 24 days [1-42]). Major risk factors associated with death directly attributable to SA were older age (p = 0.023), high C-reactive protein levels (p = 0.002), diabetes mellitus (p = 0.028), rheumatoid arthritis and other inflammatory rheumatic diseases (p = 0.021), confusion on admission (p = 0.012), bacteraemia (p = 0.015), a low creatinine clearance rate (p = 0.009) and the presence of leg ulcers/eschars (p = 0.003). The median duration of follow-up (in patients who survived for more than 6 months) was 17 months [6-43]. The proportion of poor functional outcomes was high (31.8 %). Major risk factors associated with a poor functional outcome were older age (0.049), hip joint involvement (p = 0.003), the presence of leg ulcers/eschars (p = 0.012), longer time to presentation (0.034) and a low creatinine clearance rate (p = 0.013). CONCLUSIONS: In a university hospital setting, SA is still associated with high morbidity and mortality rates.

High-resolution imaging of bone and joint architecture in rheumatoid arthritis.

INTRODUCTION: Rheumatoid arthritis (RA) is characterized by local and systemic bone loss caused by increased bone resorption. We describe the current utilization of high-resolution peripheral quantitative computed tomography (HR-pQCT) in the evaluation of bone and joint in RA. SOURCES OF DATA: PubMed was searched for publications using keywords that included 'bone microarchitecture', 'high-resolution peripheral quantitative computed tomography' and 'rheumatoid arthritis'. AREAS OF AGREEMENT: HR-pQCT may simultaneously allow assessment of trabecular and cortical bone parameters and be a useful method for depicting bone erosions. AREAS OF CONTROVERSY: HR-pQCT only assesses bone microarchitecture at the distal radius and tibia. Controversy exists regarding the optimal way to differentiate cortical and trabecular regions. GROWING POINTS: Although HR-pQCT is currently a research tool, there is potential for its use in the clinical diagnosis and management in RA. Further research is required to evaluate the clinical relevance of imaging abnormalities identified in RA patients.

Bone remodelling markers in rheumatoid arthritis.

Bone loss in rheumatoid arthritis (RA) patients results from chronic inflammation and can lead to osteoporosis and fractures. A few bone remodeling markers have been studied in RA witnessing bone formation (osteocalcin), serum aminoterminal propeptide of type I collagen (PINP), serum carboxyterminal propeptide of type I collagen (ICTP), bone alkaline phosphatase (BAP), osteocalcin (OC), and bone resorption: C-terminal telopeptide of type 1 collagen (I-CTX), N-terminal telopeptide of type 1 collagen (I-NTX), pyridinolines (DPD and PYD), and tartrate-resistant acid phosphatase (TRAP). Bone resorption can be seen either in periarticular bone (demineralization and erosion) or in the total skeleton (osteoporosis). Whatever the location, bone resorption results from activation of osteoclasts when the ratio between osteoprotegerin and receptor activator of nuclear factor kappa-B ligand (OPG/RANKL) is decreased under influence of various proinflammatory cytokines. Bone remodeling markers also allow physicians to evaluate the effect of drugs used in RA like biologic agents, which reduce inflammation and exert a protecting effect on bone. We will discuss in this review changes in bone markers remodeling in patients with RA treated with biologics.

Bone health in adults with obesity before and after interventions to promote weight loss.

Obesity and its associated comorbidities constitute a serious and growing public health burden. Fractures affect a substantial proportion of people with obesity and result from reduced bone strength relative to increased mechanical loading, together with an increased risk of falls. Factors contributing to fractures in people with obesity include adverse effects of adipose tissue on bone and muscle and, in many people, the coexistence of type 2 diabetes. Strategies to reduce weight include calorie-restricted diets, exercise, bariatric surgery, and pharmacological interventions with GLP-1 receptor agonists. However, although weight loss in people with obesity has many health benefits, it can also have adverse skeletal effects, with increased bone loss and fracture risk. Priorities for future research include the development of effective approaches to reduce fracture risk in people with obesity and the investigation of the effects of GLP-1 receptor agonists on bone loss resulting from weight reduction.

Proton pump inhibitors, bone and phosphocalcic metabolism.

Proton pump inhibitors (PPIs) are widely used for acid-related gastrointestinal disorders; however, concerns have arisen about their prolonged and inappropriate use. Although generally considered safe, recent evidence has linked PPI use with an increased risk of kidney disease, stomach cancer, pneumonia, dementia, cardiovascular events and potential bone health problems. This systematic review examines the effects of PPIs on bone health, including osteoporosis and changes in phosphocalcic and magnesium metabolism, through a comprehensive analysis of the recent literature. The relationship between PPIs, bone mineral density and fracture risk, especially in populations with comorbidities, is complex and we propose a focus based on recent data. Studies of the effect of PPI use on bone mineral density have shown mixed results and require further investigation. Observational studies have indicated an increased risk of fractures, particularly vertebral fractures, associated with PPI use. Recent meta-analyses have confirmed an association between PPI use and hip fractures with a dose-dependent effect. More recently, PPIs have been associated with serious disturbances in phosphocalcic and magnesium metabolism that require careful management and discontinuation. Proton pump inhibitor-induced hypomagnesemia (PPIH) is a well-established phenomenon. In addition, hypocalcemia secondary to severe hypomagnesemia has been described. Despite growing evidence of PPI-related risks, further research is essential to better understand the complex mechanisms, as most data are from observational studies and do not establish a causal relationship. This review emphasizes the need for judicious prescription practices, particularly in long-term use scenarios and rheumatological contexts.

Association between sarcopenia and risk of major adverse cardiac and cerebrovascular events-UK Biobank database.

BACKGROUND: Few studies on the risk of incident major adverse cardiac and cerebrovascular events (MACCEs) in sarcopenia have been reported. The objective was to assess the association between presarcopenia and sarcopenia and a higher risk of MACCEs. METHODS: This study on the UK Biobank prospective cohort, used data collected between 2006 and 2021. Community-dwelling Caucasian participants aged 37 to 73 years were included if values for Handgrip Strength (HGS) and Skeletal Muscle Index (SMI) were available and if no history of MACCEs was reported. Exposure was assessed using the European Working Group on Sarcopenia in Older People 2 (EWGSOP2) criteria. Muscle strength was measured using HGS, and muscle mass using the SMI. Presarcopenia was defined through the two definitions available in the literature, as low HGS with normal SMI and as normal HGS with low SMI, whereas sarcopenia was defined as low HGS with low SMI. The main outcome was to determine whether presarcopenia and/or sarcopenia were predictors of MACCEs (composite events). RESULTS: A total of 406,411 included participants (women: 55.7%) were included. At baseline, there were 18,257 (4.7%) presarcopenics-subgroup n°1 (low HGS only), 7940 (2.1%) presarcopenics-subgroup n°2 (low SMI only), and 1124 (0.3%) sarcopenics. Over a median follow-up of 12.1 years (IQR: [11.4; 12.8]), 28,300 participants (7.0%) were diagnosed with at least one event. Compared to NonSarc, presarcopenic (subgroups n°1 and n°2) and sarcopenic status were significantly associated with a higher risk of MACCEs (respectively fully adjusted HRs: HR = 1.25 [95% CI: 1.19; 1.31], HR = 1.33 [95% CI: 1.23; 1.45] and HR = 1.62 [95% CI: 1.34; 1.95]). CONCLUSIONS: In a community-dwelling population, the risk of MACCEs was higher in both presarcopenic and sarcopenic participants.

Bone mineral density T-scores comparison between obese and non-obese individuals included in a Fracture Liaison Service following a recent fragility fracture.

We used data from a Fracture Liaison Service to compare the mean T-scores of obese and non-obese patients after a recent fragility fracture. After adjusting for age, sex, and diabetes mellitus, T-score values were significantly higher at all measurement sites in obese patients, with a mean difference of 1 SD. PURPOSE: This study aimed to compare the mean T-scores of obese and non-obese patients after recent fragility fractures. METHODS: Over a period of 5 and a half years, from January 2016 to May 2021, patients from a fracture liaison service were identified and their demographic characteristics, osteoporosis risk factors, BMD T-scores, and fracture sites were compared between obese (BMI ≥ 30 kg/m2) and non-obese (19 kg/m2 < BMI < 30 kg/m2) patients. RESULTS: A total of 712 patients were included (80.1% women; mean age 73.8 ± 11.3 years). Sixteen % had type 2 diabetes mellitus and 80% had a major osteoporotic fracture (MOF). 135 patients were obese and 577 non-obese, with obese patients younger (p < 0.001) and more frequently female (p = 0.03). Obese patients presented with fewer hip fractures (10% vs. 21%, p = 0.003) and more proximal humerus fractures (16% vs. 7%, p < 0.001) than non-obese patients. After adjusting for age, sex, and diabetes mellitus, BMD T-score values were significantly higher at all measurement sites (lumbar spine, total hip, and femoral neck) in obese patients than in non-obese patients for all types of fractures, with a mean difference of 1 standard deviation (p < 0.001 for all comparisons). The same results were observed in the population limited to MOF. CONCLUSIONS: Given the crucial role of BMD T-score in determining the need for anti-osteoporotic medication following fragility fractures, it is reasonable to question the existing T-score thresholds in obese patients.

Characteristics of difficult-to-treat axial spondyloarthritis: Results of a real-world multicentric study.

OBJECTIVE: The EULAR task force recently published the difficult-to-treat RA (D2T RA) definition, however, a definition of D2T axSpA is still lacking and limitations in this definition exist. The objectives were to study the characteristics of D2T axSpA patients using the EULAR definition and to study a subgroup of patients with a predefined more stringent definition including a temporal criterion. METHODS: A multicentric retrospective study was performed. D2T axSpA was defined as failure of≥2 b/tsDMARDs with different mechanism of action. Very D2T axSpA was defined as failure of≥2 b/tsDMARDs in less than 2 years of follow-up. D2T and Very D2T axSpA patients were compared to non-D2T (nD2T) axSpA patients. RESULTS: Three hundred and eleven axSpA patients were included: 88 D2T axSpA (28.3%) and 223 non-D2T (nD2T) axSpA (71.7%). Peripheral involvement was more prevalent in the D2T group (34.9 vs. 21.4%; P=0.015). BASDAI level at baseline was higher in the D2T group (63.7±16.5 vs. 58.8±14.7; P=0.015). Fibromyalgia was found to be more frequent in the D2T group vs nD2T group (P<0.001). Twelve patients (3.8%) were categorized as very D2T axSpA. Compared to nD2T, Very D2T patients had a higher CRP level at baseline (42.0±31.3 vs. 17.8±23.1; P=0.010). IBD prevalence at baseline was higher in the very D2T group (41.7 vs. 3.1%; P<0.001). None of the very D2T patients presented a fibromyalgia. CONCLUSION: D2T axSpA was associated with higher disease activity, peripheral involvement, extra-musculoskeletal manifestations and fibromyalgia. Very D2T patients represented a minim proportion of patients after applying a more stringent definition including a temporal criterion of 2 years and might be independent from fibromyalgia.

Romosozumab versus parathyroid hormone receptor agonists: which osteoanabolic to choose and when?

Osteoanabolic agents are used as a first line treatment in patients at high fracture risk. The PTH receptor 1 (PTH1R) agonists teriparatide (TPTD) and abaloparatide (ABL) increase bone formation, bone mineral density (BMD), and bone strength by activating PTH receptors on osteoblasts. Romosozumab (ROMO), a humanized monoclonal antibody against sclerostin, dramatically but transiently stimulates bone formation and persistently reduces bone resorption. Osteoanabolic agents increase BMD and bone strength while being more effective than antiresorptives in reducing fracture risk in postmenopausal women. However, direct comparisons of the antifracture benefits of osteoanabolic therapies are limited. In a direct comparison of TPTD and ABL, the latter resulted in greater BMD increases at the hip. While no differences in vertebral or non-vertebral fracture risk were observed between the two drugs, ABL led to a greater reduction of major osteoporotic fractures. Adverse event profiles were similar between the two agents except for hypercalcemia, which occurred more often with TPTD. No direct comparisons of fracture risk reduction between ROMO and the PTH1R agonists exist. Individual studies have shown greater increases in BMD and bone strength with ROMO compared with TPTD in treatment-naive women and in women previously treated with bisphosphonates. Some safety aspects, such as a history of tumor precluding the use of PTH1R agonists, and a history of major cardiovascular events precluding the use of ROMO, should also be considered when choosing between these agents. Finally, convenience of administration, reimbursement by national health systems and length of clinical experience may influence patient choice.

A novel deep learning method for large-scale analysis of bone marrow adiposity using UK Biobank Dixon MRI data.

Background: Bone marrow adipose tissue (BMAT) represents > 10% fat mass in healthy humans and can be measured by magnetic resonance imaging (MRI) as the bone marrow fat fraction (BMFF). Human MRI studies have identified several diseases associated with BMFF but have been relatively small scale. Population-scale studies therefore have huge potential to reveal BMAT's true clinical relevance. The UK Biobank (UKBB) is undertaking MRI of 100,000 participants, providing the ideal opportunity for such advances. Objective: To establish deep learning for high-throughput multi-site BMFF analysis from UKBB MRI data. Materials and methods: We studied males and females aged 60-69. Bone marrow (BM) segmentation was automated using a new lightweight attention-based 3D U-Net convolutional neural network that improved segmentation of small structures from large volumetric data. Using manual segmentations from 61-64 subjects, the models were trained to segment four BM regions of interest: the spine (thoracic and lumbar vertebrae), femoral head, total hip and femoral diaphysis. Models were tested using a further 10-12 datasets per region and validated using datasets from 729 UKBB participants. BMFF was then quantified and pathophysiological characteristics assessed, including site- and sex-dependent differences and the relationships with age, BMI, bone mineral density, peripheral adiposity, and osteoporosis. Results: Model accuracy matched or exceeded that for conventional U-Nets, yielding Dice scores of 91.2% (spine), 94.5% (femoral head), 91.2% (total hip) and 86.6% (femoral diaphysis). One case of severe scoliosis prevented segmentation of the spine, while one case of Non-Hodgkin Lymphoma prevented segmentation of the spine, femoral head and total hip because of T2 signal depletion; however, successful segmentation was not disrupted by any other pathophysiological variables. The resulting BMFF measurements confirmed expected relationships between BMFF and age, sex and bone density, and identified new site- and sex-specific characteristics. Conclusions: We have established a new deep learning method for accurate segmentation of small structures from large volumetric data, allowing high-throughput multi-site BMFF measurement in the UKBB. Our findings reveal new pathophysiological insights, highlighting the potential of BMFF as a novel clinical biomarker. Applying our method across the full UKBB cohort will help to reveal the impact of BMAT on human health and disease.

Cystic fibrosis-related bone disease.

PURPOSE OF REVIEW: This review highlights recently published data on the pathophysiology, guidelines and treatment of cystic fibrosis (CF)-related bone disease. RECENT FINDINGS: The exact role of the cystic fibrosis transmembrane conductance regulator (CFTR), specifically the ΔF508 allele, has been investigated in F508del-CFTR homozygous mice and the F508del-CFTR mutation may contribute to CF-related bone disease by slowing new bone formation. The European Cystic Fibrosis Society has issued guidelines for bone mineral density assessment, management of low-trauma fractures and bisphosphonate therapy. A systematic review based on meta-analyses reports that oral and intravenous bisphosphonates both improve bone mineral density in CF patients, but no data are available concerning the reduction of low-trauma fractures. SUMMARY: European Cystic Fibrosis Society guidelines may help physicians to improve the management of CF-related bone disease.

Effectiveness of fracture liaison services in osteoporosis.

BACKGROUND: In response to the gradual decline in the number of prescriptions for anti-osteoporosis medication (AOM) following fragility fractures, fracture liaison services (FLSs) have been set up around the world with the aim of filling this treatment gap. Several studies have already reported the benefits of such organizations, particularly in reducing fracture risk, mortality rates and healthcare costs, and literature on FLSs has increased at a steady pace over time. METHODS: A narrative review was conducted on the latest available findings on the effectiveness of FLSs. Various approaches to implementing an effective FLS program are discussed. RESULTS: FLS programs have enhanced the management of osteoporosis-related fractures. However, several studies have highlighted that not all FLSs are necessarily effective in reducing subsequent fracture risk and mortality. Long-term AOM persistence and monitoring are another critical issue in FLS programs. A few studies have reported that FLSs are associated with an improvement in AOM persistence, regardless of the type of AOM. Practitioners in the FLS setting need to be aware of the impact of recency of fracture and fracture recurrence rates, and the need for timely interventions. The administration of zoledronic acid in an in-patient setting may improve AOM treatment rates in patients, who often encounter obstacles to outpatient follow-up. Introducing 'vertebral fracture identification services' in FLS programs is also an option. However, doing so leads to an increase in workload and this would need to be considered by any FLS that is considering introducing such a service. Evidence suggests that digital technologies can support (i) multidisciplinary teams in providing the best possible patient care based on current evidence, and (ii) patient self-management. However, as the methodological quality of many of the studies evaluating these technologies was poor, their validity of their results is limited. CONCLUSION: Further research should focus on the optimal implementation of post-fracture care using automated systems, and standardized reporting of patient's characteristics and outcome measures using key performance indicators.