Interaction between bone and immune cells: Implications for postmenopausal osteoporosis.

Postmenopausal osteoporosis is a systemic disease characterized by the loss of bone mass and increased bone fracture risk largely resulting from significantly reduced levels of the hormone estrogen after menopause. Besides the direct negative effects of estrogen-deficiency on bone, indirect effects of altered immune status in postmenopausal women might contribute to ongoing bone destruction, as postmenopausal women often display a chronic low-grade inflammatory phenotype with altered cytokine expression and immune cell profile. In this context, it was previously shown that various immune cells interact with osteoblasts and osteoclasts either via direct cell-cell contact, or more likely via paracrine mechanisms. For example, specific subtypes of T lymphocytes express TNFα, which was shown to increase osteoblast apoptosis and to indirectly stimulate osteoclastogenesis via B cell-produced receptor-activator of NF-κB ligand (RANKL), thereby triggering bone loss during postmenopausal osteoporosis. Th17 cells release interleukin-17 (IL-17), which directs mesenchymal stem cell differentiation towards the osteogenic lineage, but also indirectly increases osteoclast differentiation. B lymphocytes are a major regulator of osteoclast formation via granulocyte colony-stimulating factor secretion and the RANKL/osteoprotegerin system under estrogen-deficient conditions. Macrophages might act differently on bone cells dependent on their polarization profile and their secreted paracrine factors, which might have implications for the development of postmenopausal osteoporosis, because macrophage polarization is altered during disease progression. Likewise, neutrophils play an important role during bone homeostasis, but their over-activation under estrogen-deficient conditions contributes to osteoblast apoptosis via the release of reactive oxygen species and increased osteoclastogenesis via RANKL signaling. Furthermore, mast cells might be involved in the development of postmenopausal osteoporosis, because they store high levels of osteoclastic mediators, including IL-6 and RANKL, in their granules and their numbers are greatly increased in osteoporotic bone. Additionally, bone fracture healing is altered under estrogen-deficient conditions with the increased presence of pro-inflammatory cytokines, including IL-6 and Midkine, which might contribute to healing disturbances. Consequently, in addition to the direct negative influence of estrogen-deficiency on bone, immune cell alterations contribute to the pathogenesis of postmenopausal osteoporosis.

Conditioned medium of human mesenchymal stem cells affects stem cell senescence in osteoporosis.

Systemic transplantation of mesenchymal stem cells (MSCs) and conditioned medium derived from MSCs have been reported to recover bone loss in animal models of osteoporosis; however, the underlying mechanisms remain unclear. We recently reported that extracellular vesicles released from human mesenchymal stem cells (hMSCs) prevent senescence of stem cells in bisphosphonate-related osteonecrosis of the jaw model. In this study, we aimed to compare the effects of conditioned medium (hMSCs-CM) from early and late passage hMSCs on cellular senescence and to verify the benefits of CM from early passage hMSCs in mitigating the progression of osteoporosis through the prevention of cellular senescence. We investigated the distinct endocrine effects of early (P5) and late (P17) passage hMSCs in vitro, as well as the preventive benefits of early passage hMSCs-CM in osteoporosis model triggered by ovariectomy. Our results indicate that long-term cultured hMSCs contributed to the progression of inflammatory transcriptional programs in P5 hMSCs, ultimately impairing their functionality and enhancing senescence-related characteristics. Conversely, early passage hMSCs reversed these alterations. Moreover, early passage hMSCs-CM infused intravenously in a postmenopausal osteoporosis mouse model suppressed bone degeneration and prevented osteoporosis by reducing ovariectomy-induced senescence in bone marrow MSCs and reducing the expression of senescence-associated secretory phenotype-related cytokines. Our findings highlight the high translational value of early passage hMSCs-CM in antiaging intervention and osteoporosis prevention.

Bone-Targeted Biomimetic Nanogels Re-Establish Osteoblast/Osteoclast Balance to Treat Postmenopausal Osteoporosis.

Insufficient bone formation and excessive bone resorption caused by estrogen deficiency are the major factors resulting in the incidence of postmenopausal osteoporosis (PMOP). The existing drugs usually fail to re-establish the osteoblast/osteoclast balance from both sides and generate side-effects owing to the lack of bone-targeting ability. Here, engineered cell-membrane-coated nanogels PNG@mR&C capable of scavenging receptor activator of nuclear factor-κB ligand (RANKL) and responsively releasing therapeutic PTH 1-34 in the bone microenvironment are prepared from RANK and CXCR4 overexpressed bone mesenchymal stem cell (BMSC) membrane-coated chitosan biopolymers. The CXCR4 on the coated-membranes confer bone-targeting ability, and abundant RANK effectively absorb RANKL to inhibit osteoclastogenesis. Meanwhile, the release of PTH 1-34 triggered by osteoclast-mediated acid microenvironment promote osteogenesis. In addition, the dose and frequency are greatly reduced due to the smart release property, prolonged circulation time, and bone-specific accumulation. Thus, PNG@mR&C exhibits satisfactory therapeutic effects in the ovariectomized (OVX) mouse model. This study provides a new paradigm re-establishing the bone metabolic homeostasis from multitargets and shows great promise for the treatment of PMOP.

An investigation of the differential therapeutic effects of romosozumab on postmenopausal osteoporosis patients with or without rheumatoid arthritis complications: a case-control study.

The impact of ROMO on the width of anabolic windows and the increase in BMD was reduced in the RA group compared to the non-RA group, and this reduction was associated with correlations to RA-related factors. PURPOSE: To investigate the effects of romosozumab (ROMO) in postmenopausal osteoporosis, with and without comorbid rheumatoid arthritis (RA). METHODS: In this retrospective, case-controlled, multicenter study, 171 postmenopausal patients who did not receive oral glucocorticoid, comprising 59 in the RA group and 121 in the non-RA group, received uninterrupted ROMO treatment for 12 months. Propensity score matching was employed to ensure comparability in clinical backgrounds, resulting in 41 patients in each group. Baseline characteristics were as follows: overall (mean age, 76.3 years; T-score of lumbar spine (LS), - 3.0; 45.1% were treatment-naive for osteoporosis); RA group (anti-cyclic citrullinated peptide antibody (ACPA) positivity, 80.5%; titer, 206.2 U/ml; clinical disease activity index (CDAI), 13.6; health assessment questionnaire disability index (HAQ-DI), 0.9). Bone mineral density (BMD) and serum bone turnover markers were monitored over a 12-month period. RESULTS: The rate of increase in the bone formation marker, PINP, and the rates of decrease in the bone resorption marker, TRACP-5b, exhibited a trend toward smaller changes in the RA group compared to the non-RA group, implying a smaller anabolic window. After 12 months, the RA group displayed lower BMD increases in the LS (9.1% vs. 12.6%; P = 0.013) and total hip (2.4% vs. 4.8%; P = 0.025) compared to the non-RA group. Multiple regression analysis in the all RA group (n = 59) for the association between RA-specific factors and 12-month BMD changes revealed negative correlations between ACPA titer and LS BMD and between HAQ-DI and femoral neck BMD. CONCLUSIONS: The efficacy of ROMO may be attenuated by RA-related factors.

The relationship between length of denosumab treatment for postmenopausal osteoporosis and serum TRAcP5b measured six months after the last injection.

To test the hypothesis that during treatment with denosumab osteomorphs and precursors recycle to higher number of osteoclasts with time, we measured TRAcP5b in serum taken 6 months after the last injection in postmenopausal women treated for 1-10 years. Serum TRAcP5b values were not related to time of exposure to denosumab. PURPOSE: In women with postmenopausal osteoporosis the aetiology of the observed inverse relationship between duration of denosumab (Dmab) therapy and bone loss after its discontinuation is currently unknown. In studies in mice inhibition of RANKL is associated with an increase in osteomorphs and osteoclast precursors that recycle into osteoclasts and may accumulate with time. We hypothesized that longer inhibition of RANKL by Dmab will be followed by the synchronous formation of a larger number of osteoclasts after stopping treatment. To test this hypothesis, we measured serum TRAcP5b, a marker of osteoclast numbers, in postmenopausal women treated with Dmab for different periods of time up to 10 years. METHODS: TRAcP5b, C-terminal telopeptide of type 1 collagen (CTX) and procollagen type 1 N-terminal propeptide (P1NP) were measured at 6.0 months ± 15 days after last Dmab injection in 59 women who had received Dmab for 4.0 ± 2.3 years (range 1-10 years). Of these, 38 were treatment naïve (group 1) and 21 had received other treatments prior Dmab (group 2). RESULTS: Duration of Dmab treatment was not related to serum TRAcP5b values or to TRAcP5b/CTX ratio either in the whole cohort or in each of the two groups separately. In contrast, serum TRAcP5b values were significantly correlated with serum CTX values (rs = 0.619; p < 0.001), but not with serum P1NP values or BMD at all skeletal sites. CONCLUSION: Our observations indicate that serum TRAcP5b, measured at 6 months after a Dmab injection, is not a useful early marker for time-dependent increased accumulation of osteoclasts in humans and for identification of patients at risk for a higher rebound increase in bone resorption.

Pre-treatment bone turnover does not influence the level of the response to alendronate in postmenopausal osteoporosis at the bone tissue level.

PURPOSE: The main effect of anti-resorptive agents such as bisphosphonates is a reduction of bone resorption, with a consequent marked decrease of bone turnover. This post-hoc analysis investigated the changes of histomorphometric parameters of bone turnover after alendronate (ALN), according to the baseline turnover. METHODS: Ninety postmenopausal women underwent a transiliac bone biopsy before and after 6 (n = 44) or 12 (n = 46) months of treatment with ALN (70 mg/week). The dynamic parameters reflecting the bone formation and bone turnover were mineralizing surface (MS/BS; %), bone formation rate (BFR/BS; µm3/µm2/d), and activation frequency (Ac.f; /yr). Biochemical markers sPINP and the sCTX were assessed before treatment and after 3, 6, and 12 months. Subjects were divided into quartiles based on the baseline values of BFR/BS. RESULTS: At baseline, MS/BS and Ac.f were significantly different (p < 0.0001) among the BFR quartiles. sCTX and sP1NP were not significantly different among quartiles. After ALN treatment, MS/BS was not significantly different among quartiles but Ac.f remained significantly lower in the first quartile compared to the third and fourth ones (p < 0.03). The absolute value of the difference between pre- and post-treatment significantly correlated with the baseline BFR/BS but when expressed in percent of the baseline value, the magnitude of the diminutions of MS/BS, Ac.f, sCTX, and sP1NP was similar in the four baseline BFR quartiles. CONCLUSION: The percentage response to ALN appeared independent of the baseline level of bone turnover. After treatment, the bone turnover tended to be similar in all BFR quartiles. This analysis investigated the influence of baseline turnover measured by bone histomorphometry on the effect of alendronate. When expressed in percent of pre-treatment values, the decreases of histomorphometric parameters and biochemical markers of bone turnover were independent of the baseline turnover.

Clinical effects of teriparatide, abaloparatide, and romosozumab in postmenopausal osteoporosis.

In the management of osteoporosis, anti-resorptive agents serve as a primary therapeutic approach. However, in cases where individuals exhibit an increased susceptibility to fractures, such as those characterized by severe low bone mass or a history of vertebral or hip fractures that markedly diminish life expectancy, the immediate reduction of fracture risk through the administration of osteoanabolic agents could be beneficial. Teriparatide, available in daily, once-weekly, or twice-weekly dosages, along with abaloparatide and romosozumab, constitutes a trio of such agents. Each of these medications is defined by unique characteristics, distinct efficacy profiles, and specific adverse effects. There is growing evidence to suggest that these agents have a superior effect on enhancing bone mineral density and reducing fracture incidence when compared to traditional bisphosphonate therapies. Nonetheless, their employment demands thorough consideration of clinical indications, which includes evaluating economic factors, the frequency of injections required, and the potential for adverse effects. The objective of this review is to consolidate the current evidence focusing primarily on the efficacy of these agents, with the goal of enhancing understanding and aiding in making more informed treatment decisions, particularly for those individuals who are at an elevated risk of fractures.

Effect of probiotics on postmenopausal bone health: a preclinical meta-analysis.

Postmenopausal osteoporosis is a major concern for women worldwide due to increased risk of fractures and diminished bone quality. Recent research on gut microbiota has suggested that probiotics can combat various diseases, including postmenopausal bone loss. Although several preclinical studies have explored the potential of probiotics in improving postmenopausal bone loss, the results have been inconsistent and the mechanism of action remains unclear. To address this, a meta-analysis was conducted to determine the effect of probiotics on animal models of postmenopausal osteoporosis. The bone parameters studied were bone mineral density (BMD), bone volume fractions (BV/TV), and hallmarks of bone formation and resorption. Pooled analysis showed that probiotic treatment significantly improves BMD and BV/TV of the ovariectomised animals. Probiotics, while not statistically significant, exhibited a tendency towards enhancing bone formation and reducing bone resorption. Next, we compared the effects of Lactobacillus sp. and Bifidobacterium sp. on osteoporotic bone. Both probiotics improved BMD and BV/TV compared with control, but Lactobacillus sp. had a larger effect size. In conclusion, our findings suggest that probiotics have the potential to improve bone health and prevent postmenopausal osteoporosis. However, further studies are required to investigate the effect of probiotics on postmenopausal bone health in humans.

lncTIMP3 promotes osteogenic differentiation of bone marrow mesenchymal stem cells via miR-214/Smad4 axis to relieve postmenopausal osteoporosis.

BACKGROUND: Promoting the balance between bone formation and bone resorption is the main therapeutic goal for postmenopausal osteoporosis (PMOP), and bone marrow mesenchymal stem cells (BMSCs) osteogenic differentiation plays an important regulatory role in this process. Recently, several long non-coding RNAs (lncRNAs) have been reported to play an important regulatory role in the occurrence and development of OP and participates in a variety of physiological and pathological processes. However, the role of lncRNA tissue inhibitor of metalloproteinases 3 (lncTIMP3) remains to be investigated. METHODS: The characteristics of BMSCs isolated from the PMOP rat model were verified by flow cytometry assay, alkaline phosphatase (ALP), alizarin red and Oil Red O staining assays. Micro-CT and HE staining assays were performed to examine histological changes of the vertebral trabeculae of the rats. RT-qPCR and western blotting assays were carried out to measure the RNA and protein expression levels. The subcellular location of lncTIMP3 was analyzed by FISH assay. The targeting relationships were verified by luciferase reporter assay and RNA pull-down assay. RESULTS: The trabecular spacing was increased in the PMOP rats, while ALP activity and the expression levels of Runx2, Col1a1 and Ocn were all markedly decreased. Among the RNA sequencing results of the clinical samples, lncTIMP3 was the most downregulated differentially expressed lncRNA, also its level was significantly reduced in the OVX rats. Knockdown of lncTIMP3 inhibited osteogenesis of BMSCs, whereas overexpression of lncTIMP3 exhibited the reverse results. Subsequently, lncTIMP3 was confirmed to be located in the cytoplasm of BMSCs, implying its potential as a competing endogenous RNA for miRNAs. Finally, the negative targeting correlations of miR-214 between lncTIMP3 and Smad4 were elucidated in vitro. CONCLUSION: lncTIMP3 may delay the progress of PMOP by promoting the activity of BMSC, the level of osteogenic differentiation marker gene and the formation of calcium nodules by acting on the miR-214/Smad4 axis. This finding may offer valuable insights into the possible management of PMOP.

The combination of Butyricicoccus pullicaecorum and 3-hydroxyanthranilic acid prevents postmenopausal osteoporosis by modulating gut microbiota and Th17/Treg.

BACKGROUND: Postmenopausal osteoporosis (PMO) is a chronic condition characterized by decreased bone strength. This study aims to investigate the effects and mechanisms of the combination of Butyricicoccus pullicaecorum (Bp) and 3-hydroxyanthranilic acid (3-HAA) on PMO. METHODS: The effects of Bp and 3-HAA on PMO were evaluated in ovariectomized (OVX) rats by assessing stereological parameters, femur microstructure, and autophagy levels. The T helper (Th) 17/Regulatory T (Treg) cells of rats were detected using flow cytometric analysis. Furthermore, the impact of Bp and 3-HAA on the gut microbiota of rats was assessed using 16S rRNA gene sequencing. The correlation between the gut microbiota of rats and Th17/Treg immune factors, as well as femoral stereo parameters, was separately assessed using Spearman rank correlation analysis. RESULTS: Bp and 3-HAA treatments protected OVX rats by promoting osteogenesis and inhibiting autophagy. Compared to the Sham group, OVX rats showed an increase in Th17 cells and a decrease in Treg cells. Bp and 3-HAA reversed these changes. Enterorhabdus and Pseudomonas were significantly enriched in OVX rats. Bp and 3-HAA regulated the gut microbiota of OVX rats, enriching pathways related to nutrient metabolism and immune function. There was a correlation between the gut microbiota and the Th17/Treg, as well as femoral stereo parameters. The concurrent administration of Bp and 3-HAA medication facilitated the enrichment of gut microbiota associated with the improvement of PMO. CONCLUSION: The combination therapy of Bp and 3-HAA can prevent PMO by modulating the gut microbiota and restoring Th17/Treg immune homeostasis.

Targeting the Role of PRME in Regulating Bone Remodelling During Postmenopausal Osteoporosis.

Kariavattom Campus Postmenopausal osteoporosis (PMO) is an old age disorder associated with estrogen deficiency, which reduces bone mass and makes bones more prone to fracture. The present study was proposed to evaluate the invivo osteogenic efficiency of Pterospermum rubiginosum methanolic bark extract (PRME) in the PMO model. Molecular docking studies on transcription factor NFATC1 showed excellent interactions with phytochemical ligands with the lowest binding energies. Female Sprague Dawley (SD) rats (n=24) were divided into four groups, (n=6 each) sham control (Group I) and osteoporotic control (Group II) groups treated with saline, PRME (50 mg/kg/day) and alendronate (10 mg/kg/day) treated with Group III and Group IV (n=6) respectively. The serum tartrate-resistant acid phosphatase 5b and cathepsin-K also exhibited a significant rise after PRME treatment 12.33±2.30 mU/ml and 427.68±46.97 pg/ml, respectively. DEXA results exhibited a remarkable increase in total bone mineral content and density values in PRME-treated animals (0.175±0.002 g/cm2) and (7.95±0.23 g) when compared to osteoporotic control (0.163±0.004 g/cm2) and (6.83±0.34 g). Long-term toxicity study revealed that PRME is non-toxic, up to 100 mg/kg bodyweight for 6 months. Our findings suggest PRME protects osteoporotic SD rats from PMO damage resulting from estrogen deficiency by regulating bone remodelling markers and upregulating BMD indices.

Eupatilin ameliorates postmenopausal osteoporosis via elevating microRNA-211-5p and repressing JAK2/STAT3 pathway.

Postmenopausal osteoporosis (PMOP) poses a significant threat to women's health worldwide. Eupatilin is a key bioactive component of the Chinese herbal medicine Artemisia asiatica Nakai. Recent research reports have proved the inhibitory function of Eupatilin in many diseases. MicroRNAs (miRNAs) are 21-23 nucleotide-long, single-stranded, noncoding RNA molecules generated endogenously, and many studies have indicated that miRNAs are involved in the development of osteoporosis. This study explored the role and potential mechanism of Eupatilin underlying PMOP. First, rats were given intragastric administration of Eupatilin every day and subcutaneous injections of oligonucleotides or plasmids that interfered with miR-211-5p or janus kinase 2 (JAK2) once a week. After 4 weeks, the PMOP rat model was established. Then, serum alkaline phosphatase, calcium, and phosphorus levels, as well as femur bone mineral density and biomechanical parameters, were detected. Hematoxylin-eosin staining and Masson staining were applied for detecting the pathological condition of femur, and immunohistochemical staining was for detecting osteocalcin. MC3T3-E1 cells were transfected with plasmid vectors interfering with miR-211-5p or JAK2; and cell viability, lactate dehydrogenase cytotoxicity, and cell mineralization were subsequently examined. The relationship between miR-211-5p and JAK2/signal transducer and activator of transcription 3 (STAT3) pathway was analyzed. The targeting relation between miR-211-5p and JAK2 was also verified. The experimental results revealed that Eupatilin improved the pathological conditions of PMOP rats by promoting the proliferation and mineralization of osteoblasts. MiR-211-5p was down-regulated and JAK2/STAT3 was upregulated in PMOP rats. Upregulation of miR-211-5p further improved the pathological conditions of PMOP rats based on Eupatilin treatment. MiR-211-5p inhibited the JAK2/STAT3 pathway. JAK2 offset the effects of elevated miR-211-5p on PMOP rats. Overall, Eupatilin attenuates PMOP through elevating miR-211-5p and repressing JAK2/STAT3 pathway, which suggests the utility of Eupatilin as a potential drug for POMP treatment.

Farnesyl Diphosphate Synthase Gene Associated with Loss of Bone Mass Density and Alendronate Treatment Failure in Patients with Primary Osteoporosis.

Aminobisphosphonates (NBPs) are the first-choice medication for osteoporosis (OP); NBP treatment aims at increasing bone mineral density (BMD) by inhibiting the activity of farnesyl diphosphate synthase (FDPS) enzyme in osteoclasts. Despite its efficacy, inadequate response to the drug and side effects have been reported. The A allele of the rs2297480 (A > C) SNP, found in the regulatory region of the FDPS gene, is associated with reduced gene transcription. This study evaluates the FDPS variant rs2297480 (A > C) association with OP patients' response to alendronate sodium treatment. A total of 304 OP patients and 112 controls were enrolled; patients treated with alendronate sodium for two years were classified, according to BMD variations at specific regions (lumbar spine (L1-L4), femoral neck (FN) and total hip (TH), as responders (OP-R) (n = 20) and non-responders (OP-NR) (n = 40). We observed an association of CC genotype with treatment failure (p = 0.045), followed by a BMD decrease in the regions L1-L4 (CC = -2.21% ± 2.56; p = 0.026) and TH (CC = -2.06% ± 1.84; p = 0.015) after two years of alendronate sodium treatment. Relative expression of the FDPS gene was also evaluated in OP-R and OP-NR patients. Higher expression of the FDPS gene was also observed in OP-NR group (FC = 1.84 ± 0.77; p = 0.006) when compared to OP-R. In conclusion, the influence observed of FDPS expression and the rs2897480 variant on alendronate treatment highlights the importance of a genetic approach to improve the efficacy of treatment for primary osteoporosis.

Liuwei Dihuang pills attenuate ovariectomy-induced bone loss by alleviating bone marrow mesenchymal stem cell (BMSC) senescence via the Yes-associated protein (YAP)-autophagy axis.

CONTEXT: Liuwei Dihuang pill (LWDH) has been used to treat postmenopausal osteoporosis (PMOP). OBJECTIVE: To explore the effects and mechanisms of action of LWDH in PMOP. MATERIALS AND METHODS: Forty-eight female Sprague-Dawley rats were divided into four groups: sham-operated (SHAM), ovariectomized (OVX), LWDH high dose (LWDH-H, 1.6 g/kg/d) and LWDH low dose (LWDH-L, 0.8 g/kg/d); the doses were administered after ovariectomy via gavage for eight weeks. After eight weeks, the bone microarchitecture was evaluated. The effect of LWDH on the differentiation of bone marrow mesenchymal stem cells (BMSCs) was assessed via osteogenesis- and lipogenesis-induced BMSC differentiation. The senescence-related biological indices were also detected using senescence staining, cell cycle analysis, quantitative real-time polymerase chain reaction and western blotting. Finally, the expression levels of autophagy-related proteins and Yes-associated protein (YAP) were evaluated. RESULTS: LWDH-L and LWDH-H significantly modified OVX-induced bone loss. LWDH promoted osteogenesis and inhibited adipogenesis in OVX-BMSCs. Additionally, LWDH decreased the positive ratio of senescence OVX-BMSCs and improved cell viability, cell cycle, and the mRNA and protein levels of p53 and p21. LWDH upregulated the expression of autophagy-related proteins, LC3, Beclin1 and YAP, in OVX-BMSCs and downregulated the expression of p62. DISCUSSION AND CONCLUSIONS: LWDH improves osteoporosis by delaying the BMSC senescence through the YAP-autophagy axis.

Association between P1NP value and increases in bone mineral density in patients with postmenopausal osteoporosis treated with romosozumab.

OBJECTIVES: The present study aimed to investigate the effectiveness of treatment with romosozumab for one year and association between bone turnover markers and changes in bone mineral density (BMD) in patients with postmenopausal osteoporosis (PMO). METHODS: Participants were 53 treatment-naïve PMO patients. Correlations of percent changes (Δ) in lumbar (L) and total hip (TH) BMD 12 months after initiating romosozumab with baseline demographic factors and parameters of N-terminal propeptide of type 1 collagen (P1NP) and tartrate-resistant acid phosphatase (TRACP)-5b at baseline and months 1, 3 and 6 were assessed. Multiple regression analysis was performed on factors significantly correlated with ΔL-BMD and ΔTH-BMD at month 12. RESULTS: ΔL-BMD and ΔTH-BMD at month 12 were 17.5% and 8.1%, respectively. Multiple regression analysis revealed that a high P1NP value at month 3 predicted large increases in L-BMD and TH-BMD at month 12. High total amount of P1NP values from baseline to month 6 was associated with large increases in L-BMD and TH-BMD at month 12, and was most strongly correlated with the P1NP value at month 3. CONCLUSIONS: A high P1NP value at month 3 predicted large increases in both L-BMD and TH-BMD at month 12 in PMO patients treated with romosozumab.

Strontium ranelate enriched Ruminococcus albus in the gut microbiome of Sprague-Dawley rats with postmenopausal osteoporosis.

BACKGROUND: Gut microbiome is critical to our human health and is related to postmenopausal osteoporosis (PMO). Strontium ranelate (SrR) is an anti-osteoporosis oral drug that can promote osteoblast formation and inhibit osteoclast formation. However, the effect of SrR on gut microbiome has been rarely studied. Therefore, we investigated the effect of oral SrR on gut microbiome and metabolic profiles. RESULTS: In this study, we used ovariectomized (OVX) Sprague-Dawley rats to construct a PMO model and applied oral SrR for 6 weeks. The relative abundance of intestinal microbiome was investigated by 16S rRNA metagenomic sequencing. Ultra-high-performance liquid chromatography-mass spectrometry (UHPLC-MS) was used to analyze changes in metabolites of intestinal contents. Results demonstrated that 6-week oral SrR alleviated osteoporosis and significantly changed the composition of the gut microbiome and metabolic profiles of OVX rats. Ruminococcus, Akkermansia and Oscillospira were significantly enriched in the gut of OVX rats after 6-week oral SrR. Especially, the species R. albus showed the greatest importance by a random forest classifier between OVX and OVX_Sr group. The enrichment of R. albus in the gut was positively correlated with bone mineral density and the accumulation of lycopene and glutaric acid, which also significantly elevated after oral SrR. CONCLUSIONS: We discovered that oral SrR can improve bone health while stimulate the accumulation of gut microbe R. albus and metabolites (lycopene and glutaric acid). The results suggested possible connections between oral SrR and the gut-bone axis, which may provide new insight into the treatment/prevention of osteoporosis.

The potential of Klebsiella and Escherichia-Shigella and amino acids metabolism to monitor patients with postmenopausal osteoporosis in northwest China.

BACKGROUND: Intestinal flora has been proposed to mediate the occurrence of postmenopausal osteoporosis (PMO). However, the mechanism by which microbes and their metabolites interactively promote PMO remains unknown. METHODS: This study aimed to investigate changes in the intestinal flora and associated metabolites, and their role in PMO. 16S rRNA gene sequencing and metabolomics were performed to obtain postmenopausal women with osteopenia (lower bone mass, LBM), postmenopausal women with osteoporosis (OST), and healthy women as the control group. RESULTS: We identified taxa-specific and metabolite differences in the intestinal flora of the participants of this study. The pathogenic bacteria Klebsiella (0.59% and 0.71%, respectively) and Escherichia-Shigella (2.72% and 4.30%, respectively) were enriched in the LBM and OST groups (p < 0.05). Some short-chain fatty acid (SCFAs) producing bacteria, Lactobacillus, Akkermansia, Prevotella, Alistipes, and Butyricicoccus, were reduced in patients with LBM and OST compared to the control. Moreover, fecal metabolomic analyses suggested that the metabolites of indole-3-acetic acid and 7-ketodeoxycholic acid were altered in the LBM and OST groups compared to the control (p < 0.05). Enrichment analysis suggested that valine, leucine, and isoleucine biosynthesis; aromatic amino acid biosynthesis; and phenylalanine metabolism were significantly associated with the identified microbiota biomarkers and OST. Moreover, metabolite marker signatures distinguished patients in the OST from those in the control group with an area under the curve (AUC) of 0.978 and 1.00 in the negative and positive ion modes, respectively. Finally, we also found that the fecal level of interleukin-10 (IL-10) in the OST group was significantly lower than that in the control group and LBM group (p < 0.05), while tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) were significantly higher in the OST group than that in the control group (p < 0.05). CONCLUSIONS: This study provides robust evidence connecting the intestinal flora and fecal metabolomics with PMO. Integrated metabolite and microbiota analyses demonstrated that in addition to dysregulated bacteria, indole-3-acetic acid, 7-ketodeoxycholic acid, and other metabolites can be used for the distinguish of LBM and PMO.

Baseline serum PINP level is associated with the increase in hip bone mineral density seen with Romosozumab treatment in previously untreated women with osteoporosis.

Baseline serum PINP value was significantly and independently associated with the increased bone mineral density (≥ 3%) in both total hip and femoral necks by 12 months of romosozumab treatment in patients with treatment-naive postmenopausal osteoporosis. PURPOSE: Some patients fail to obtain a sufficiently increased hip bone mineral density (BMD) by romosozumab (ROMO) treatment. This study aimed to investigate the prognostic factor for increased hip BMD with ROMO in patients with treatment-naive postmenopausal osteoporosis. METHODS: This prospective, observational, and multicenter study included patients (n = 63: mean age, 72.6 years; T-scores of the lumbar spine [LS], - 3.3; total hip [TH], - 2.6; femoral neck [FN], - 3.3; serum type I procollagen N-terminal propeptide [PINP], 68.5 µg/L) treated by ROMO for 12 months. BMD and serum bone turnover markers were evaluated at each time point. A responder analysis was performed to assess the patient percentage, and both univariate and multivariate analyses were performed to investigate the factors associated with clinically significant increased BMD (≥ 3%) in both TH and FN. RESULTS: Percentage changes of BMD from baseline in the LS, TH, and FN areas were 17.5%, 4.9%, and 4.3%, respectively. In LS, 96.8% of patients achieved ≥ 6% increased LS-BMD, although 57.1% could not achieve ≥ 3% increased BMD in either TH or FN. Multiple regression analysis revealed that only the baseline PINP value was significantly and independently associated with ≥ 3% increased BMD in both TH and FN (p = 0.019, 95% confidence interval = 1.006-1.054). The optimal cut-off PINP value was 53.7 µg/L with 54.3% sensitivity and 92.3% specificity (area under the curve = 0.752). CONCLUSIONS: In a real-world setting, baseline PINP value was associated with the increased BMD of TH and FN by ROMO treatment in treatment-naive patients.

Comparison of the Efficacy of Zoledronate Acid or Denosumab After Switching from Romosozumab in Japanese Postmenopausal Patients.

We aimed to compare the efficacy of switching from romosozumab (RMAb) to denosumab (DMAb) or zoledronic acid (Zol) with respect to changes in bone mineral density (BMD) and bone metabolism. We also aimed to determine predictors of changes in BMD among patients who received sequential therapy from RMAb. One hundred patients who received RMAb therapy were recruited for this study. A total 49 patients received bisphosphonate (BP) pre-treatment and 51 received active vitamin D3 analog pre-treatment or no treatment. Forty-two patients were switched to Zol (BP-RMAb-Zol; 20 and RMAb-Zol; 22), and 58 patients were switched to DMAb (BP-RMAb-DMAb; 29 and RMAb-DMAb; 29). Longitudinal changes in bone metabolic markers (P1NP and TRACP-5b) and BMD were also evaluated. In the BP-RMAb-Zol group, TRACP-5b increased after administration of Zol, and the mean BMD of the lumbar spine (LS) was significantly lower than those in the BP-RMAb-DMAb, RMAb-Zol and RMAb-DMAb groups at 24 months. The % changes in BMD of the LS after 24 months were associated with TRACP-5b values at baseline and at 12 months in patients who received Zol therapy, and with TRACP-5b value at baseline in patients who received DMAb therapy. The DMAb follow-on regimen could be considered more effective than Zol as a sequential agent for the enhancement of BMD after RMAb in patients with BP pretreatment. TRACP-5b, especially the baseline value, may predict the efficacy of sequential therapy from RMAb, as well as previous treatments.

Low Unsaturated Fatty Acids Level in the Vertebral Bone Marrow of Postmenopausal Osteoporosis: A Pilot 2D iDQC-MRS on 3.0 T Study.

BACKGROUND: Unsaturated fatty acids (UFAs) of bone marrow play a critical role in osteoporosis. However, it is difficult to resolve the UFA, especially in the presence of trabecular bone, using conventional magnetic resonance spectroscopy (MRS) methods. PURPOSE: To preliminarily compare the bone marrow fatty acids (FAs) composition in the presence of trabecular bone of postmenopausal osteoporosis (PMOP) and healthy controls (HC). STUDY TYPE: Prospective. SUBJECTS: Total thirty-six postmenopausal women were recruited with CT-confirmed PMOP (n = 19) and HC (n = 17). FIELD STRENGTH/SEQUENCES: A 3 T scanner. Localized 2D intermolecular double-quantum coherence-based MRS (iDQC-MRS). ASSESSMENT: In addition to the conventional water and fat peaks, another four crossing peaks of the FAs were well resolved from the L4 vertebral bone marrow using iDQC-MRS technique: allylic methylene (2.0 ppm), terminal methylene (2.2 ppm), diallylic methylene (2.7 ppm), and olefinic (5.3 ppm). The monounsaturated fatty acids (MOFA) and polyunsaturated fatty acids (PUFAs) were then calculated. STATISTICAL TESTS: Differences between PMOP and HC were investigated using the analysis of a t-test, and the relationships were investigated using regression analysis. RESULTS: MOFAs and PUFAs fractions were significantly lower in the PMOP group compared to the HC group. In contrast, the saturated FAs fraction is significantly higher in the PMOP group. Additionally, decreased PUFAs, MOFAs were moderately negatively correlated with the volumetric bone mineral density (vBMD) in the PMOP group. Furthermore, increased SFAs in PMOP were strongly associated with vBMD. DATA CONCLUSION: Using spectra resolution enhanced 2D iDQC-MRS technique, we observed low unsaturated FAs levels in the vertebral bone marrow of the PMOP patients. The reduced unsaturated FAs levels in PMOP may be associated with dysfunction of the balance between osteoblastogenesis and osteoclastogenesis. TECHNICAL EFFICACY STAGE: 1.