Journal of Bone and Mineral Metabolism最新文献

Background: Fibroblast growth factor 23 (FGF23)-related hypophosphatemic rickets/osteomalacia arises from excessive FGF23 activity, with X-linked hypophosphatemia (XLH) and tumor-induced osteomalacia (TIO) as the most common congenital and acquired forms, respectively. However, in a substantial subset of patients with acquired FGF23-related hypophosphatemic osteomalacia, phosphaturic mesenchymal tumors (PMTs) remain undetectable despite extensive imaging studies. A recent study identified autoantibodies against PHEX, the gene responsible for XLH, in 5 of 13 patients with acquired FGF23-related osteomalacia without detectable PMTs, thereby defining a novel disease entity termed autoimmune osteomalacia (AIO). Clinically, AIO presents with milder disease activity than TIO, comparable in severity to XLH.

Findings: Some patients exhibited concomitant autoimmune disorders, and whole-genome sequencing revealed rare variants in autoimmune susceptibility genes, suggesting a genetic predisposition. Therapeutic options include burosumab and, potentially, immunosuppressive therapy such as glucocorticoids. Long-term follow-up indicates that AIO patients may develop ectopic ossifi cation, similar to XLH. Anti-PHEX autoantibodies were detected using both luciferase immunoprecipitation systems and fl ow cytometry, underscoring the importance of complementary methods for detecting antibodies against native conformational epitopes.

Conclusions: Recognition of AIO should be particularly considered in patients with acquired FGF23-related hypophosphatemia who have undetectable PMTs, relatively mild disease activity, and concurrent autoimmune diseases.

Introduction: This study aimed to clarify trends in the incidence of secondary hip fractures and pharmacotherapy after primary fractures over time in Japan.

Materials and methods: Using Japan's National Database of Health Insurance Claims and Specific Health Checkups, we examined the number of hip fracture patients and their osteoporosis medication status from fiscal year (FY) 2012 to FY2023.

Results: A total of 1,289,333 females and 312,968 males had primary fractures. Among them, 42,835 females and 8,249 males had a secondary fracture within 1 year following the primary fracture. The incidence rates averaged 3.44% annually, ranging from 3.26 to 3.57% by fiscal year. These rates showed an increasing trend from FY2012 to FY2018, followed by a decreasing trend until FY2020, but increased again in FY2021. The medication administration rate within the first year following the primary fracture progressively increased over time, from 39.1% in FY2012 to 49.6% in FY2021, followed by a notable increase to 65.5% in FY2022. Bisphosphonates were the most frequently administered medications, and the number of patients receiving bisphosphonates, eldecalcitol, denosumab, and romosozumab increased over time.

Conclusion: The medication administration rate has consistently increased. The incidence of secondary fractures decreased from FY2019 but then increased in FY2021 due to the impact of the coronavirus disease 2019 (COVID-19) pandemic. However, in FY2022, this increase was mitigated by the introduction of management fees. It is anticipated that the incidence of secondary fractures will decline again due to a further increase in medication rates following the COVID-19 pandemic.

Introduction: This study aimed to investigate the relationship between Osteoporosis (OP) and Complex Regional Pain Syndrome type 1 (CRPS-1), in the hypothesis that OP can influence the epidemiological and clinical features of CRPS-1.

Materials and methods: From March 2013 to May 2024, consecutive patients newly diagnosed with CRPS-1 were recruited. Demographic and clinical variables were collected in a standardised fashion. Univariate analyses and multivariate linear regression models were used to investigate the sample.

Results: We enrolled 425 patients, mostly females (70.1%), more than half (52.2%) with a fracture as the inciting event. A previous OP diagnosis was found in 113 patients (26.6%). Variables significantly associated with OP were female gender, hand localisation, fracture as the inciting event, and a more severe CRPS-1. A fracture in patients with OP seems to trigger CRPS-1 mainly in women in the first decade after menopause, while in males and in older women a weaker association was observed. Multivariate analysis showed a correlation between OP and a more severe CRPS-1 (p = 0.014).

Conclusion: A higher incidence of OP was observed more frequently in women with CRPS-1 in the first decade after menopause. This result could be driven by the proinflammatory cytokines increase observed in the early menopause, inducing both a faster systemic bone loss and an "inflammatory milieu" acting as a predisposing factor for CRPS-1 onset and a more severe disease.

Introduction: Though low serum magnesium (Mg) levels are associated with adverse outcomes in patients on haemodialysis, the interaction with calcimimetics remains uncertain. We hypothesized a potential interaction between serum Mg levels and calcimimetic use in cardiovascular events (CVEs), all-cause mortality, and new fractures during follow-up in patients on haemodialysis.

Materials and methods: This single-centre retrospective cohort included 399 Japanese adults on maintenance haemodialysis, followed for ≤ 5 years. Cox models with time-dependent serum Mg levels and calcimimetic usage interaction adjusted for clinicodemographic and biochemical covariates.

Results: At baseline, 205 patients (51.4%) were prescribed calcimimetics (median serum Mg, 2.5 mg/dL). The mean observational period was 40.6 months, and 122 CVEs, 159 all-cause mortality, and 69 new fractures occurred (incidence rates: 0.09, 0.10-, and 0.05 per patient-year), respectively. The time-dependent model showed serum Mg < 2.4 mg/dL was associated with a markedly higher risk for new fractures in calcimimetic-naïve patients. Serum Mg levels were not significantly associated with CVEs and all-cause mortality, regardless of calcimimetic usage. The restricted cubic spline curve demonstrated linear inverse trends of serum Mg levels with all-cause mortality and new fractures in calcimimetic-naïve patients. However, no significant interaction between Mg and calcimimetic use was observed for any outcome.

Conclusion: We did not detect a statistically significant interaction between serum Mg levels and calcimimetic use. Nonetheless, low serum Mg (< 2.4 mg/dL) was associated with a higher risk of fractures, particularly among calcimimetic-naïve patients. Thus, low serum Mg is a potentially modifiable risk marker associated with fracture risk, particularly in calcimimetic-naïve patients.

Introduction: Studies launched in Japan on once-weekly teriparatide (1/W-TPTD) and twice-weekly teriparatide (2/W-TPTD) are limited. Therefore, we examined the effects of sequential therapy using anti-resorptive agents after administering 1/W-TPTD and 2/W-TPTD using dual-energy X-ray absorptiometry (DXA) and DXA-based 3D modeling.

Materials and methods: This was a multicenter retrospective study following a phase 3 clinical trial called the TWICE study. Two-year follow-up data were collected after administering 1/W-TPTD or 2/W-TPTD for 1 year (follow-up after the phase 3 clinical trial).

Results: 20 subjects in the group of pre-treatments with 1/W-TPTD followed by sequential administration of bisphosphonate or denosumab (1/W-TPTD [BP/denosumab]), and 22 in the group 2/W-TPTD (BP/denosumab) were included in the analysis of changes in the BMD by post-treatment. In the 1/W-TPTD (BP/denosumab) group, a significant increase in L2-4 BMD was observed. In the 2/W-TPTD (BP/denosumab) group, a significant increase in total hip, neck, and L2-4 BMD values was observed. Analysis by 3D-SHAPER revealed that both the 1/W-TPTD (BP/denosumab) and 2/W-TPTD (BP/denosumab) groups demonstrated significant increases in cortical sBMD and vBMD 2 years after the initiation of post-treatment.

Conclusion: In subjects who received 1/W-TPTD and 2/W-TPTD for about 1 year followed by sequential administration of BP or denosumab, significant improvements in BMD were continuously observed. Furthermore, significant improvements in cortical sBMD and vBMD were also demonstrated by analysis using 3D-SHAPER. Both 1/W-TPTD and 2/W-TPTD were effective in the treatment of osteoporosis by using anti-resorptive agents for sequential administration.

Background: Skeletal stem cells (SSCs) underlie skeletal development, homeostasis, regeneration, and aging, yet their identities and functions are highly heterogeneous across anatomical sites and life stages. Mouse genetic studies have identified multiple SSC populations-each residing in distinct niches such as the growth plate, periosteum, and bone marrow-and revealed their dynamic regulation across developmental, homeostatic, regenerative, and aging contexts. However, translating these insights to humans remains challenging due to species differences and limited access to physiological human skeletal tissues. This review synthesizes current understanding of SSC diversity and how distinct compartments contribute to skeletal formation and maintenance throughout life. It also summarizes emerging human skeletal modeling strategies, including pluripotent stem cell differentiation, bioengineered in vitro systems, and in vivo transplantation, evaluating their ability to reconstruct skeletal components and SSC-bearing niches. Although recent models reproduce partial structures such as perichondrium-like layers or bone marrow-like microenvironments, most remain compartment-specific and lack integrated, stage-aware architectures that recapitulate physiological SSC behavior and skeletal functions in vivo. We propose an SSC-centric framework that incorporates spatiotemporal diversity, multi-compartment integration, physiological cues, and cross-validation with human tissues, providing predictive and translational platforms for skeletal biology, disease modeling, and regenerative medicine.