Personalising osteoporosis treatment for patients at high risk of fracture

Rapid and relaying deleterious effects of a gastrointestinal pathogen, Citrobacter rodentium, on bone, an extra-intestinal organ

Enteropathogenic infections cause pathophysiological changes in the host but their effects beyond the gastrointestinal tract are undefined. Here, using Citrobacter rodentium infection in mouse, which mimics human diarrheal enteropathogenic Escherichia coli, we show that gastrointestinal infection negatively affects bone remodeling, leading to compromised bone architecture. Transmission of infection through fecal-oral route from Citrobacter rodentium-infected to non-infected mice caused bone loss in non-infected cage mates. Mice with B cell deficiency (Igh6-/- mice) failed to clear C. rodentium infection and exhibited more severe and long-term bone loss compared to WT mice. Unbiased cytokine profiling showed an increase in circulating tumor necrosis factor α (TNFα) levels following Citrobacter rodentium infection, and immunoneutralization of TNFα prevented infection-induced bone loss completely in WT and immunocompromised mice. These findings reveal rapid, relaying, and modifiable effects of enteropathogenic infections on an extraintestinal organ-bone, and provide insights into the mechanism(s) through which these infections affect extraintestinal organ homeostasis.

Diagnostic power of vertebral hydroxyapatite concentration measurements in spectral CT for osteoporosis-associated fractures and impact of intravenous contrast administration

OBJECTIVES

To evaluate the diagnostic power of using vertebral hydroxyapatite concentration measurements in unenhanced and contrast-enhanced spectral CT for detecting and predicting the risk of osteoporosis-associated fractures.

METHODS

L1 of 210 patients (105 men, 105 women; mean age, 64 years, range, 19-103 years) who had undergone spectral CT examinations from January 1, 2018, to March 1, 2019, were retrospectively analyzed. Patient data for 3 years after spectral CT were retrieved from electronic medical record information systems to obtain the incidence of osteoporotic fractures. Baseline vertebral cancellous hydroxyapatite concentration from unenhanced and contrast-enhanced late-arterial-phase images was measured. The receiver operating characteristic curves were used to evaluate the diagnostic power for detecting and predicting the 3-year risk of osteoporosis-associated fractures using hydroxyapatite concentrations in both phases.

RESULTS

The hydroxyapatite concentrations in both phases had good diagnostic power to detect fractures at baseline. The sensitivity and specificity for predicting one or more osteoporosis-associated fractures within 3 years after spectral CT were 76.80% and 93.10%, respectively, using the cutoff of 74.79 mg/cm³ in vertebral hydroxyapatite concentration in the unenhanced CT phase, and 82.87% and 82.76%, respectively, using the cutoff of 84.65 mg/cm³ in the late-arterial phase. Furthermore, there was no significant difference in the diagnosis between unenhanced and enhanced CT-derived hydroxyapatite concentrations (p = 0.360).

CONCLUSIONS

Both unenhanced and enhanced spectral CT-derived hydroxyapatite concentrations can accurately detect and predict future risk of osteoporosis-associated fractures. The hydroxyapatite concentration assessed in the late-arterial phase may have a similar diagnostic efficacy to that in the unenhanced phase.

KEY POINTS

• A cutoff of 74.79 mg/cm³ of vertebral hydroxyapatite concentration in the unenhanced CT scans had 76.80% sensitivity and 93.10% specificity to predict one or more osteoporosis-associated fractures within 3 years after spectral CT examinations. • A cutoff of 84.65 mg/cm³ of vertebral hydroxyapatite concentration in the late-arterial-enhanced CT scans had 82.87% sensitivity and 82.76% specificity to predict one or more osteoporosis-associated fractures within 3 years after spectral CT examinations. • The hydroxyapatite concentration assessed in the late-arterial phase may have a similar diagnostic efficacy to that in the unenhanced phase.

Osteoporosis clinical practice guideline: romosozumab for treating severe osteoporosis – an update by the Egyptian Academy of Bone Health

Background

This is a Clinical Practice Guideline update released by the Egyptian Academy of Bone Health and Metabolic Bone Diseases. It does not replace the clinical practice guidelines published for the treatment of osteoporosis in 2021, but it entails specific recommendations and selective criteria for romosozumab as another pharmacological agent for treatment of postmenopausal osteoporosis. It has been issued, in part, due to the imminent approval of romosozumab in Egypt.

Main text

The guideline recommends the use of romosozumab, for up to 1 year, for the reduction of vertebral, hip, and non-vertebral fractures in postmenopausal women with severe osteoporosis at very high risk of fracture/imminent fracture risk: defined as T-score less than − 2.5 and a prior hip or vertebral fracture in the past 24 months or a very high fracture risk, as identified by FRAX (FRAX major osteoporosis fracture > 30%, FRAX hip fracture > 4.5%). The recommended dosage of romosozumab is 210 mg monthly by subcutaneous injection for 12 months. For osteoporotic postmenopausal women who have completed a 12-month course of romosozumab, treatment with an anti-resorptive osteoporosis therapy is recommended to maintain bone mineral density gains and reduce fracture risk. The treatment is not recommended for women at high risk of cardiovascular disease and stroke, which includes those with prior myocardial infarction or stroke.

In conclusion, strategies to osteoporosis management have been highly diversified, with bone health specialists have become able to set up treatment plan tailored to the individual patient’s requirement. Patients with severe osteoporosis at very high fracture risk need stronger therapeutic regimens to start with. Romosozumab endorses bone formation and suppresses bone resorption, leading to a greater anabolic window and a superior positive impact on bone mineral density.

Study on the influence of balloon dilation mode on the intravertebral cleft of osteoporotic fracture

BACKGROUND

Intravertebral cleft is common in osteoporotic vertebral compression fracture, and the bone sclerosis around the fissure brings difficulties to the surgical treatment. It is not known whether the balloon dilatation mode of percutaneous kyphoplasty affects the distribution of bone cement in the fracture vertebral body and further affects the surgical effect. The purpose of this study was to discuss the effect of balloon dilatation mode on percutaneous kyphoplasty in the treatment of osteoporotic vertebral fractures with intravertebral cleft.

METHODS

According to the inclusion criteria and exclusion criteria, a retrospective analysis of patients with osteoporotic vertebral fracture combined with intravertebral cleft treated by percutaneous kyphoplasty in our hospital was conducted. All patients were divided into two groups based on way of balloon dilation. The mode of balloon dilatation, imaging changes of vertebral body, VAS score, ODI score, bone cement distribution and postoperative complications were analyzed.

RESULTS

A total of 96 patients with osteoporotic vertebral fracture combined with intravertebral cleft were included in the study, including 51 patients treated with single balloon bilateral alternating dilatation technique and 45 patients treated with double balloon bilateral dilatation technique. The vertebral height, Cobb's angle of kyphosis, VAS score and ODI score were significantly improved in both groups after operation (P < 0.05). The postoperative vertebral height and Cobb's angle of kyphosis in the double balloon bilateral dilatation group were better than those in single balloon bilateral alternating dilatation group (P < 0.05). The distribution of bone cement in the single balloon bilateral alternating dilatation group was more inclined to insert filling, while the double balloon bilateral dilatation group was more inclined to fissure filling. The VAS score and ODI score at the final follow-up in the single balloon bilateral alternating dilatation group were lower than those in the double balloon bilateral dilatation group (P < 0.05).

CONCLUSION

Double balloon bilateral dilatation technique can better restore the injured vertebral height in patients with osteoporotic vertebral fracture combined with intravertebral cleft. However, the distribution of injured vertebral cement in patients with single balloon bilateral alternating dilatation technique is more likely to be inserted and filled, and the long-term analgesia and lumbar function of patients are better.

CMTM3 suppresses bone formation and osteogenic differentiation of mesenchymal stem cells through inhibiting Erk1/2 and RUNX2 pathways

Osteoporosis, fracture, large-scale craniofacial defects and osteonecrosis are hot topics and are still underdiagnosed and undertreated in the clinic. It is urgent to understand the molecular mechanisms corresponding to the regulation of bone formation. CMTM3 (CKLF-like MARVEL transmembrane domain containing 3) connects the classic chemokine to the transmembrane 4 superfamily and plays an important role in intracellular vesicles transport, EGF receptor function maintenance and cancer development. However, its expression and function in bone remain unclear. In this paper, we found that the bone volume/total volume, trabecular number, trabecular thickness and bone surface area/bone volume of Cmtm3 KO mice increased significantly, and trabecular separation and trabecular pattern factor decreased in Cmtm3 KO mice compared with WT mice by microcomputed tomography. Moreover, the bone mineral content, bone mineral density, ultimate force and stiffness were also increased in Cmtm3 KO mice. Using in vitro analysis, we showed that CMTM3 expression decreases during the differentiation of hBMSCs to osteoblasts. Knockdown of CMTM3 promoted ALP and mineralization of hBMSCs and facilitated osteoblastic differentiation with increasing RUNX2 expression. However, overexpression of CMTM3 got the opposite results. These results proved that CMTM3 was essential for osteogenic differentiation. In addition, knockdown of CMTM3 enhanced p-Erk1/2, but had no significant effect on p-Akt or p-STAT3 in hBMSCs and MC3T3-E1 cells. Taken together, our results indicated that Erk1/2 and RUNX2 pathways mediated by CMTM3 were involved in the process of osteogenic differentiation, and CMTM3 might be a new potential target in the treatment of bone formation-related disease.

Investigation of Diagnostic Biomarkers for Osteoporosis Based on Differentially Expressed Gene Profile with QCT and mDixon-Quant Techniques

OBJECTIVE

To develop a comprehensive differential expression profile for osteoporosis based on two independent data sources.

METHODS

Using a hindlimb unloading (HLU) rat model to mimic osteoporosis syndrome in humans (animal experiments), the significant differentially expressed mRNAs in osteoporosis were analyzed using RNA-seq. The enriched GO terms as well as KEGG signaling pathways were also deeply investigated. Using clinical specimens to verify the functions of potential hub genes (biomarkers) for osteoporosis (clinical experiments), 128 suspected cases for osteoporosis from January 2019 to December 2020 were randomly selected and analyzed by quantitative computed tomography (QCT) as well as modified Dixon quantification (mDixon-Quant) techniques in the Tianjin hospital. Among these, 80 patients out of 128 suspected cases were finally diagnosed as the osteoporosis group. Meanwhile, 48 patients were selected for osteopenia group. There was no significant age and gender difference across participant subgroups. The protein levels of potential hub genes (FST, CCL3, and RAPGEF4) were determined by ELISA double antibody sandwich method for osteopenia and osteoporosis groups from peripheral blood.

RESULT

In the RNA-seq analysis, compared with control group, a total of 803 differentially expressed mRNAs were identified, including 288 up-regulated and 515 down-regulated mRNAs. Of these, FST, CCL3, CPE, RAPGEF4, IL6, MDFI, PDZD2, and GATM were primary hub genes (biomarkers) for osteoporosis. These differentially expressed genes were significantly enriched in GO terms related to extracellular matrix process and KEGG signaling pathways including osteoclast differentiation. In the functional experiments, the protein expression level of FST, CCL3, and RAPGEF4 displayed a specific expression pattern between osteoporosis patients and control group. The protein concentration of FST was 23.63 ± 6.39 ng/mL in osteoporosis patients compared as 48.36 ± 9.12 ng/mL in osteopenia group (P < 0.01). Meanwhile, CCL3 was 1.03 ± 0.64 ng/mL in osteoporosis patients vs 0.56 ± 0.24 in osteopenia group (P < 0.01) and RAPGEF4 was 53.58 ± 11.42 ng/mL in osteoporosis patients vs 66.47 ± 13.28 ng/mL in osteopenia group (P < 0.05), respectively.

CONCLUSION

This study has identified potential gene biomarkers (the genes with most significantly differential expression and useful for distinguishing osteoporosis from other bone disorders) and established a differential expression profile for osteoporosis, which is a valuable reference for future clinical research.

Romosozumab efficacy on fracture outcomes is greater in patients at high baseline fracture risk: a post hoc analysis of the first year of the frame study

This study aimed to determine the interaction between baseline FRAX^® fracture probability and romosozumab efficacy. Using an ITT approach, it was determined that the efficacy of romosozumab on clinical fracture, osteoporotic fracture, and major osteoporotic fracture is significantly greater in patients at high baseline fracture risk, when compared with placebo.

INTRODUCTION

Post hoc analyses of placebo-controlled osteoporosis treatment studies have shown significantly greater reductions of fracture incidence for higher fracture risk patients. This study determined the interaction between baseline FRAX^® fracture probability and romosozumab efficacy in the placebo-controlled first year of the phase 3 FRAME study (NCT01575834).

METHODS

Using an ITT approach, an extension of Poisson regression analysis studied the relationship between treatment, FRAX^® 10-year probability of major osteoporotic fracture (MOF, calculated without BMD) and risk of first incident fracture (adjusting for age and follow-up time). Treatment interactions considered outcomes of all clinical fractures, osteoporotic fractures, MOF, clinical vertebral fractures, and morphometric vertebral fractures. Two-sided p value of < 0.1 for the interaction between treatment and FRAX^® was considered significant.

RESULTS

Compared with placebo, romosozumab reduced the incidence of all fracture outcomes in the first year (range: 32% reduction in MOF [p = 0.07] to 80% reduction in clinical vertebral fractures [p = 0.038]). Significant interactions were observed between efficacy and baseline FRAX^® probability for composite outcomes of clinical fractures, osteoporotic fractures, and MOF (p = 0.064-0.084), but not vertebral fractures (p > 0.3). For example, romosozumab decreased all clinical fractures by 22% at the 25th centile of FRAX^® probability but the reduction was 41% at the 75th centile. Exclusion of vertebral fractures from each composite fracture outcome (i.e. only nonvertebral fractures included) showed even stronger interactions with baseline FRAX^® probability (p = 0.036-0.046).

CONCLUSIONS

Efficacy of romosozumab on clinical fracture, osteoporotic fracture, and MOF is significantly greater in patients at high baseline fracture risk compared with placebo.

Bone mineral density response prediction following osteoporosis treatment using machine learning to aid personalized therapy

Osteoporosis is a global health problem for ageing populations. The goals of osteoporosis treatment are to improve bone mineral density (BMD) and prevent fractures. One major obstacle that remains a great challenge to achieve the goals is how to select the best treatment regimen for individual patients. We developed a computational model from 8981 clinical variables, including demographic data, diagnoses, laboratory results, medications, and initial BMD results, taken from 10-year period of electronic medical records to predict BMD response after treatment. We trained 7 machine learning models with 13,562 osteoporosis treatment instances [comprising 5080 (37.46%) inadequate treatment responses and 8482 (62.54%) adequate responses] and selected the best model (Random Forests with area under the receiver operating curve of 0.70, accuracy of 0.69, precision of 0.70, and recall of 0.89) to individually predict treatment responses of 11 therapeutic regimens, then selected the best predicted regimen to compare with the actual regimen. The results showed that the average treatment response of the recommended regimens was 9.54% higher than the actual regimens. In summary, our novel approach using a machine learning-based decision support system is capable of predicting BMD response after osteoporosis treatment and personalising the most appropriate treatment regimen for an individual patient.

A service evaluation of e-triage in the osteoporosis outpatient clinic-an effective tool to improve patient access?

We introduced an electronic triage system into our osteoporosis service to actively manage referral demand in a busy outpatient service. Our study demonstrated the effectiveness of e-triage in supporting alternative management pathways, through use of virtual advice and direct to investigation services, to improve patient access.

PURPOSE

Osteoporosis referrals are increasing with awareness of the potential for prevention of fragility fracture and with complex decision making around management with long-term bisphosphonate therapy. We examined whether active triage of referrals might improve referral management processes and patient access to osteoporosis services.

METHODS

We implemented electronic triage (e-triage) of referrals to our osteoporosis service using the Northern Ireland electronic health care record. This included the option of 'advice only', direct to investigation with DXA or face-to-face appointments at the consultant-led complex osteoporosis service. We anticipated that there was scope to manage patient flow direct to investigation, or to provide referring clinicians with clinical advice without the need for a face-to-face assessment, at the consultant-led specialist service.

RESULTS

We reviewed e-triage outcomes of 809 referrals (692 F; 117 M) to osteoporosis specialist services (mean age 65 ± 16.5 years) over a 12-month period. There was a high degree of agreement for the triage category between the referring clinician and specialist services (741/809). 73.3% attended a face-to-face appointment at the consultant-led clinic, while active triage enabled direct to investigation (18.4%) or discharge (8.3%) in the remainder. The mean time between receipt of an electronic referral and e-triage was 3 days over the 12-month period as compared with 2.1 days (median 1.1 days) when annual leave periods were excluded.

CONCLUSION

E-triage supports effective referral management in a busy osteoporosis service. Efficiency is limited by reliance on a sole clinician and 5 day working at present. There is scope to further improve systems access through multidisciplinary team working, virtual clinics and future information technology developments.