Management of severe osteoporosis

Bajitianwan formula extract ameliorates bone loss induced by iron overload via activating RAGE/PI3K/AKT pathway based on network pharmacology and transcriptomic analysis

Osteoporosis (OP) is closely related to iron overload. Bajitianwan (BJTW) is a traditional Chinese medicine formulation used for treating senile diseases such as dementia and osteoporosis. Modern pharmacological researches have found that BJTW has beneficial effect on bone loss and memory impairment in aging rats. This paper aimed to explore the role and mechanism of BJTW in ameliorating iron overload-induced bone loss. Furthermore, BJTW effectively improved the bone micro-structure of the femur in mice, and altered bone metabolism biomarkers alkaline phosphatase (ALP) and osteocalcin (OCN) in serum, as well as oxidative indexes superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR) glutathione (GSH) and malondialdehyde (MDA) in liver. As for network pharmacology, 73 components collected from BJTW regulated 99 common targets merged in the BJTW and OP. The results of RNA-seq indicated that there were 418 potential targets in BJTW low dose group (BJTW-L) and 347 potential targets in BJTW high dose group (BJTW-H). Intriguingly, both PI3K-AKT signaling pathway and the AGEs-RAGE signaling pathway were contained in the KEGG pathways enrichment results of network pharmacology and transcriptomics, which were considered as the potential mechanism. Additionally, we verified that BJTW regulated the expression of related proteins in RAGE/PI3K-AKT pathways in MC3T3-E1 cells. In summary, BJTW has potent effect on protecting against iron overload-induced OP, and its mechanism may be related to the activation of the RAGE/PI3K-AKT signaling pathways.

Osteogenic mechanism of chlorogenic acid and its application in clinical practice

Natural polyphenols may have a role in counteracting oxidative stress, which is associated with aging and several bone-related diseases. Chlorogenic acid (CGA) is a naturally occurring polyphenolic compound formed by the esterification of caffeic and quininic acids with osteogenic, antioxidant, and anti-inflammatory properties. This review discusses the potential of CGA to enhance osteogenesis by increasing the osteogenic capacity of mesenchymal stem cells (MSCs), osteoblast survival, proliferation, differentiation, and mineralization, as well as its ability to attenuate osteoclastogenesis by enhancing osteoclast apoptosis and impeding osteoclast regeneration. CGA can be involved in bone remodeling by acting directly on pro-osteoclasts/osteoblasts or indirectly on osteoclasts by activating the nuclear factor kB (RANK)/RANK ligand (RANKL)/acting osteoprotegerin (OPG) system. Finally, we provide perspectives for using CGA to treat bone diseases.

Positive benefit-risk ratio of Psoraleae Fructus: Comprehensive safety assessment and osteogenic effects in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Psoraleae Fructus (PF), the dried fruit of Psoralea corylifolia L., is a commonly used traditional medicine that has contributed to the treatment of orthopedic diseases for thousands of years in China. However, recent PF-related liver injury reports have drawn widespread attention regarding its potential hepatotoxicity risks.

AIM OF THE STUDY

This study was aimed to evaluate the long-term efficacy and chronic toxicity of PF using a 26-week administration experiment on rats in order to simulate the clinical usage situation.

MATERIALS AND METHODS

The PF aqueous extract was consecutively administrated to rats daily at dosages of 0.7, 2.0, and 5.6 g/kg (equivalent to 1-8 times the clinical doses for humans) for as long as 26 weeks. Samples were collected after 13, 26, and 32 weeks (withdrawal for 6 weeks) since the first administration. The chronic toxicity of PF was evaluated by conventional toxicological methods, and the efficacy of PF was evaluated by osteogenic effects in the natural growth process.

RESULTS

In our experiments, only the H group (5.6 g/kg) for 26-week PF treatment demonstrated liver or kidney injury, which the injuries were reversible after 6 weeks of withdrawal. Notably, the PF treatment beyond 13 weeks showed significant benefits for bone growth and development in rats, with a higher benefit-risk ratio in female rats.

CONCLUSIONS

PF displayed a promising benefit-risk ratio in the treatment and prevention of osteoporosis, a disease that lacks effective medicine so far. This is the first study to elucidate the benefit-risk balance associated with clinical dosage and long-term use of PF, thereby providing valuable insights for rational clinical use and risk control of PF.

Secondary fracture prevention in Spanish primary care: results of the PREFRAOS Study

This study demonstrated a large treatment gap in elderly subjects experiencing fragility fracture in Spanish primary care, a low treatment persistence among subjects who do receive treatment, and more than one-quarter having no follow-up visits post-fracture. These data highlight the need to improve secondary fracture prevention in primary care.

PURPOSE

To describe osteoporosis (OP) treatment patterns and follow-up in subjects with fragility fracture seen in Spanish primary care (PC).

METHODS

This observational, retrospective chart review included subjects aged ≥ 70 years listed in the centers' records (November 2018 to March 2020), with ≥ 1 fragility fracture and prior consultation for any reason; subjects who had participated in another study were excluded. Outcomes included OP treatments and follow-up visits post-fragility fracture.

RESULTS

Of 665 subjects included, most (87%) were women; overall mean (SD) age, 82 years. Fewer than two thirds (61%) had received any prior OP treatment (women, 65%; men, 38%); of these, 38% had received > 1 treatment (women, 25%; men, 13%). Among treated subjects, the most frequent first-line treatments were alendronate (43%) and RANKL inhibitor denosumab (22%), with a higher discontinuation rate and shorter treatment duration observed for alendronate (discontinuation, 42% vs 16%; median treatment duration, 2.5 vs 2.1 years). Over one-quarter (26%) of subjects had no follow-up visits post-fragility fracture, with this gap higher in women than men (35% versus 25%). The most common schedule of follow-up visits was yearly (43% of subjects with a fragility fracture), followed by half-yearly (17%) and biennial (10%), with a similar trend in men and women. Most OP treatments were prescribed by PC physicians, other than teriparatide and zoledronate.

CONCLUSIONS

Across Spanish PC, we observed a large gap in the treatment and follow-up of elderly subjects experiencing a fragility fracture. Our data highlights the urgent need to improve secondary fracture prevention in PC.

SIRT1 and ZNF350 as novel biomarkers for osteoporosis: a bioinformatics analysis and experimental validation

BACKGROUND

Osteoporosis (OP) is characterized by bone mass decrease and bone tissue microarchitectural deterioration in bone tissue. This study identified potential biomarkers for early diagnosis of OP and elucidated the mechanism of OP.

METHODS

Gene expression profiles were downloaded from Gene Expression Omnibus (GEO) for the GSE56814 dataset. A gene co-expression network was constructed using weighted gene co-expression network analysis (WGCNA) to identify key modules associated with healthy and OP samples. Functional enrichment analysis was conducted using the R clusterProfiler package for modules to construct the transcriptional regulatory factor networks. We used the "ggpubr" package in R to screen for differentially expressed genes between the two samples. Gene set variation analysis (GSVA) was employed to further validate hub gene expression levels between normal and OP samples using RT-PCR and immunofluorescence to evaluate the potential biological changes in various samples.

RESULTS

There was a distinction between the normal and OP conditions based on the preserved significant module. A total of 100 genes with the highest MM scores were considered key genes. Functional enrichment analysis suggested that the top 10 biological processes, cellular component and molecular functions were enriched. The Toll-like receptor signaling pathway, TNF signaling pathway, PI3K-Akt signaling pathway, osteoclast differentiation, JAK-STAT signaling pathway, and chemokine signaling pathway were identified by Kyoto Encyclopedia of Genes and Genomes pathway analysis. SIRT1 and ZNF350 were identified by Wilcoxon algorithm as hub differentially expressed transcriptional regulatory factors that promote OP progression by affecting oxidative phosphorylation, apoptosis, PI3K-Akt-mTOR signaling, and p53 pathway. According to RT-PCR and immunostaining results, SIRT1 and ZNF350 levels were significantly higher in OP samples than in normal samples.

CONCLUSION

SIRT1 and ZNF350 are important transcriptional regulatory factors for the pathogenesis of OP and may be novel biomarkers for OP treatment.

Using machine learning techniques to predict the risk of osteoporosis based on nationwide chronic disease data

Osteoporosis is a major public health concern that significantly increases the risk of fractures. The aim of this study was to develop a Machine Learning based predictive model to screen individuals at high risk of osteoporosis based on chronic disease data, thus facilitating early detection and personalized management. A total of 10,000 complete patient records of primary healthcare data in the German Disease Analyzer database (IMS HEALTH) were included, of which 1293 diagnosed with osteoporosis and 8707 without the condition. The demographic characteristics and chronic disease data, including age, gender, lipid disorder, cancer, COPD, hypertension, heart failure, CHD, diabetes, chronic kidney disease, and stroke were collected from electronic health records. Ten different machine learning algorithms were employed to construct the predictive mode. The performance of the model was further validated and the relative importance of features in the model was analyzed. Out of the ten machine learning algorithms, the Stacker model based on Logistic Regression, AdaBoost Classifier, and Gradient Boosting Classifier demonstrated superior performance. The Stacker model demonstrated excellent performance through ten-fold cross-validation on the training set and ROC curve analysis on the test set. The confusion matrix, lift curve and calibration curves indicated that the Stacker model had optimal clinical utility. Further analysis on feature importance highlighted age, gender, lipid metabolism disorders, cancer, and COPD as the top five influential variables. In this study, a predictive model for osteoporosis based on chronic disease data was developed using machine learning. The model shows great potential in early detection and risk stratification of osteoporosis, ultimately facilitating personalized prevention and management strategies.

Retrospective study for correlation analysis of nutritional status with osteoporosis, sarcopenia and cognitive impairment in elderly patients with coronary heart disease

Coronary heart disease (CHD) is an abbreviation of coronary atherosclerotic heart disease, which remains challenging for diagnosis and treatment. Current study aims to explore the correlation between geriatric nutritional risk index (GNRI) and osteoporosis, sarcopenia, cognitive dysfunction in elderly patients with CHD, and to analyze the clinical diagnostic value of GNRI in the above complications. A total of 92 elderly patients with CHD treated in Suzhou Ninth People's Hospital from January 2020 to October 2023 were retrospectively collected as the experimental group, and 68 non-CHD subjects matched for sex and age in the same period of physical examination were randomly selected as the control group. Osteoporosis, sarcopenia and cognitive dysfunction were analyzed in all patients, and the correlation between GNRI and these indices in different populations was analyzed by Spearman's rank correlation. The diagnostic efficacy of GNRI in osteoporosis, sarcopenia, and cognitive impairment was analyzed by ROC curves. There was no significant difference in age, sex distribution, body mass index (BMI) and serum biological indexes between the elderly patients with CHD and the control group (all P > 0.05). Correlation analysis showed that GNRI level was positively correlated with bone mineral content (BMC), bone mineral density (BMD) T value and osteocalcin (OCN) (All r > 0, P < 0.05). In addition, GNRI levels were positively correlated with skeletal muscle mass (ASMI), grip strength and calf circumference (CC) (All r > 0, P < 0.05). However, there was no significant correlation between GNRI levels and cognitive dysfunction-related indicators (P > 0.05). In the elderly and elderly with CHD, the diagnostic AUC of GNRI was 0.875 and 0.862 in osteoporosis, and 0.912 and 0.932 in sarcopenia, respectively. The level of GNRI is significantly correlated with osteoporosis and sarcopenia. GNRI level, as an auxiliary diagnostic tool in elderly patients with CHD, exerts important clinical significance for early detection of the risk of complications, such as osteoporosis and sarcopenia.

A novel link between melatonin and circ_0005753/PTBP1/TXNIP regulatory network in the modulation of osteogenic potential in mesenchymal stem cells

Labeled with pluripotent potential, the transplantation of bone marrow mesenchymal stem cells (BMSCs) is considered as a promising strategy for treating osteoporosis (OP). Melatonin (MEL) has been investigated to be an essential regulator involved in bone metabolism, as well as BMSCs differentiation. Circular RNAs (circRNAs) are a unique kind of non-coding RNA and play an important regulatory role in OP. However, whether circRNAs are implicated in the effects of MEL on BMSCs osteogenic differentiation remains largely indeterminate. Expression of circ_0005753 in human BMSCs with MEL treatment, clinical specimens diagnosed with OP, either with ovariectomy (OVX)-induced mice, was measured by RT-qPCR. Western blot was conducted to analyze protein levels of osteogenesis-related molecules (Opg, RUNX2, ALP, BMP4) and TXNIP. RNA immunoprecipitation (RIP) and RNA pull-down assays were performed to validate the binding relationship among circ_0005753, PTBP1, and TXNIP. Alkaline phosphatase (ALP) and alizarin red staining (ARS) were performed to evaluate osteogenic capacity of BMSCs. OP mouse model was established by ovariectomy, as evaluated pathologic changes via hematoxylin-eosin (HE), Masson, and Immunohistochemistry (IHC) staining. Expression of circ_0005753 was remarkably decreased during MEL-induced osteogenic differentiation of BMSCs. Interestingly, not only circ_0005753 knockdown significantly promoted osteogenic differentiation of BMSCs, but circ_0005753 overexpression also weakened osteogenic differentiation induced by MEL treatment. Mechanistically, circ_0005753 maintained the stabilization of TXNIP mRNA via recruiting PTBP1. Additionally, reinforced circ_0005753 abrogated MEL-mediated protective effects on OP pathogenesis in a mouse model. This work shows that MEL facilitates osteogenic differentiation of BMSCs via the circ_0005753/PTBP1/TXNIP axis, which may shed light on the development of a novel therapeutic strategy to prevent OP.

Efficacy and Possible Mechanisms of Astragali Radix and its Ingredients in Animal Models of Osteoporosis: A Preclinical Review and Metaanalysis

BACKGROUND

Astragali Radix (AR) has a long history as a traditional Chinese medicine for anti-osteoporosis (OP) treatment. The aim of the study was to explore the effect and optimal regimens of AR and its main ingredients (IAR) in OP treatment.

METHODS

Eligible animal studies were searched in seven databases (PubMed, Web of Science, MEDLINE, SciELO Citation Index, Cochrane Library, China National Knowledge Infrastructure and Wanfang). The primary outcomes were bone metabolic indices. The secondary outcome measure was the anti-OP mechanism of IAR.

RESULTS

21 studies were enrolled in the study. The primary findings of the present article illustrated that IAR could significantly increase the bone mineral density (BMD), bone volume over the total volume, trabecular number, trabecular thickness, bone maximum load and serum calcium, while trabecular separation and serum C-terminal telopeptide of type 1 collagen were remarkably decreased (P < 0.05). In subgroup analysis, the BMD in the long treatment group (≥ 10 weeks) showed better effect size than the short treatment group (< 10 weeks) (P < 0.05). Modeling methods and animal sex were factors affecting serum alkaline phosphatase and osteocalcin levels.

CONCLUSION

The findings suggest the possibility of developing IAR as a drug for the treatment of OP. IAR with longer treatment time may achieve better effects regardless of animal strain and age.

Is Sliding Compression Necessary for Intramedullary Nailing Fixation of AO/OTA Type A3.3 Intertrochanteric Fracture?

OBJECTIVES

The intramedullary nail is considered the gold standard for treating AO/OTA type A3.3 intertrochanteric fractures. However, it still faces a significant rate of failure, mainly due to the critical factor of comminuted lateral wall defects leading to inadequate proximal sliding compression. The primary objective of this study is to investigate the requirement of sliding compression in the treatment of unstable AO/OTA type A3.3 intertrochanteric fractures. To achieve this, we conduct a comparative analysis between two approaches: InterTAN alone and proximal femoral anti-rotation blade nailing (PFNA) combined with lateral wall reconstruction for treating AO/OTA type A3.3 intertrochanteric fractures with lateral wall damage.

METHODS

A retrospective analysis was conducted on the clinical data of patients who underwent intramedullary nailing fixation for AO/OTA type A3.3 intertrochanteric fractures at our hospital from January 2012 to January 2022. Patient characteristics as well as treatment details, including operative time, intraoperative blood loss, weight-bearing time, fracture healing time, tip apex distance (TAD) loss, Harris hip scores (HHS), Parker-Palmer mobility score (PPMS), and postoperative complications, were collected and analyzed. Continuous variables were analyzed using independent sample t-tests, while categorical variables were examined using the chi-square test. For group comparisons, variance analysis was applied, and pairwise comparisons were conducted using the LSD-t test.

RESULTS

These patients were divided into PFNA combined with lateral wall reconstruction group (sliding compression group) and InterTAN fixation group (static fixation group) based on surgical methods. The operation time, intraoperative bleeding loss, HHS at 12 months and PPMS at 12 months in the sliding compression group were significantly higher than those in the static fixation group, and time to weight-bearing and fracture healing time were significantly lower than those in the static fixation group (p < 0.05). There were no significant differences between two groups in terms of the TAD at 2 days, 2, and 12 months postoperatively, the incidence of complications (p > 0.05). At 6 months postoperatively, femoral neck length was shortened compared to 2 days postoperatively in both groups, and the sliding compression group had a significantly greater degree of femoral neck shortening than the static fixation group (p < 0.05).

CONCLUSION

The use of PFNA with lateral wall reconstruction for A3.3 intertrochanteric fractures demonstrated superior mobility, efficiency, and reduced internal fixation failure rates compared to InterTAN. These findings suggest that sliding compression may be required for intramedullary nailing treatment.

Astragalus polysaccharide promotes osteogenic differentiation of human bone marrow derived mesenchymal stem cells by facilitating ANKFY1 expression through miR-760 inhibition

Aims

Astragalus polysaccharide (APS) participates in various processes, such as the enhancement of immunity and inhibition of tumours. APS can affect osteoporosis (OP) by regulating the osteogenic differentiation of human bone mesenchymal stem cells (hBMSCs). This study was designed to elucidate the mechanism of APS in hBMSC proliferation and osteoblast differentiation.

Methods

Reverse transcriptase polymerase chain reaction (RT-PCR) and Western blotting were performed to determine the expression of microRNA (miR)-760 and ankyrin repeat and FYVE domain containing 1 (ANKFY1) in OP tissues and hBMSCs. Cell viability was measured using the Cell Counting Kit-8 assay. The expression of cyclin D1 and osteogenic marker genes (osteocalcin (OCN), alkaline phosphatase (ALP), and runt-related transcription factor 2 (RUNX2)) was evaluated using quantitative reverse transcriptase polymerase chain reaction (qRT-PCR). Mineral deposits were detected through Alizarin Red S staining. In addition, Western blotting was performed to detect the ANKFY1 protein levels following the regulation of miR-760. The relationship between miR-760 and ANKFY1 was determined using a luciferase reporter assay.

Results

The expression of miR-760 was upregulated in OP tissues, whereas ANKFY1 expression was downregulated. APS stimulated the differentiation and proliferation of hBMSCs by: increasing their viability; upregulating the expression levels of cyclin D1, ALP, OCN, and RUNX2; and inducing osteoblast mineralization. Moreover, APS downregulated the expression of miR-760. Overexpression of miR-760 was found to inhibit the promotive effect of APS on hBMSC differentiation and proliferation, while knockdown of miR-760 had the opposite effect. ANKFY1 was found to be the direct target of miR-760. Additionally, ANKFY1 participated in the APS-mediated regulation of miR-760 function in hBMSCs.

Conclusion

APS promotes the osteogenic differentiation and proliferation of hBMSCs. Moreover, APS alleviates the effects of OP by downregulating miR-760 and upregulating ANKFY1 expression.

Machine learning algorithms for diagnosis of hip bone osteoporosis: a systematic review and meta-analysis study

BACKGROUND

Osteoporosis is a significant health problem in the skeletal system, associated with bone tissue changes and its strength. Machine Learning (ML), on the other hand, has been accompanied by improvements in recent years and has been in the spotlight. This study is designed to investigate the Diagnostic Test Accuracy (DTA) of ML to detect osteoporosis through the hip dual-energy X-ray absorptiometry (DXA) images.

METHODS

The ISI Web of Science, PubMed, Scopus, Cochrane Library, IEEE Xplore Digital Library, CINAHL, Science Direct, PROSPERO, and EMBASE were systematically searched until June 2023 for studies that tested the diagnostic precision of ML model-assisted for predicting an osteoporosis diagnosis.

RESULTS

The pooled sensitivity of univariate analysis of seven studies was 0.844 (95% CI 0.791 to 0.885, I² = 94% for 7 studies). The pooled specificity of univariate analysis was 0.781 (95% CI 0.732 to 0.824, I² = 98% for 7 studies). The pooled diagnostic odds ratio (DOR) was 18.91 (95% CI 14.22 to 25.14, I² = 93% for 7 studies). The pooled mean positive likelihood ratio (LR⁺) and the negative likelihood ratio (LR^-) were 3.7 and 0.22, respectively. Also, the summary receiver operating characteristics (sROC) of the bivariate model has an AUC of 0.878.

CONCLUSION

Osteoporosis can be diagnosed by ML with acceptable accuracy, and hip fracture prediction was improved via training in an Architecture Learning Network (ALN).

LncRNA LINC00205 stimulates osteoporosis and contributes to spinal fracture through the regulation of the miR-26b-5p/KMT2C axis

BACKGROUND

Osteoporosis (OP) is a common bone disease marked by decreased bone strength. Increasing evidence suggests that long non-coding RNA (lncRNAs) play important roles in the occurrence and progression of OP. This study aimed to investigate the role and mechanism of LINC00205 in the osteogenic differentiation of human mesenchymal stem cells (hMSCs) and OP.

METHODS

Bone tissue samples were obtained from healthy controls and patients with osteoporosis with a spinal fracture (OP-Frx) or without a spinal fracture (OP-no-Frx). HMSCs were cultured and induced to undergo osteogenic differentiation. The expression of LINC00205, lysine (K)-specific methyltransferase 2C (KMT2C), and miR-26b-5p in bone tissues and cells was evaluated using western blotting and real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR). The effects of LINC00205, miR-26b-5p, and KMT2C on calcium deposition, alkaline phosphatase (ALP) activity, and mRNA levels of the osteogenic differentiation marker genes [ALP, osteocalcin (OCN), and runt-related transcription factor 2 (RUNX2)] were investigated using alizarin red S staining, an ALP activity assay, and qRT-PCR, respectively. Dual-luciferase reporter assay was performed to ascertain the binding relationship between miR-26b-5p and LINC00205/KMT2C.

RESULTS

LINC00205 and KMT2C were upregulated in patients with OP-Frx and OP-no-Frx, whereas miR-26b-5p was downregulated. Furthermore, LINC00205 and KMT2C expression decreased, whereas that of miR-26b-5p increased over time from day 7 to 21 of the osteogenic differentiation of hMSCs. The knockdown of LINC00205 and KMT2C significantly increased ALP activity, calcium deposition, and the expression of RUNX2, ALP, and OCN. In contrast, the inhibition of miR-26b-5p yielded the opposite result. These data suggest that LINC00205 inhibits the osteogenic differentiation of hMSCs by modulating the miR-26b-5p/KMT2C signaling axis.

CONCLUSION

LINC00205 promotes OP and is involved in spinal fractures. LINC00205 is also a potential negative regulator of the osteogenic differentiation of hMSCs.

The role of rehabilitation and anabolic treatment in severe os-teoporosis associated with significant vitamin D deficiency – case report

It is well known that vitamin D deficiency increases the risk of osteoporosis and that vertebral compressions fractures are a manifestation of osteoporosis. This paper presents the case of a patient with severe osteoporosis associated with vitamin D deficiency who developed over the course of two years multiple vertebral compression fractures. Method: We present the case of a 76-year-old caucasian female diagnosed with osteoporosis and significant vitamin D deficiency who was investigated for mechanical pain and functional deficit at the level of the spine and walking disorders. The patient was hospitalized in our Rehabilitation department twice. At the first hospitalization two years ago, the deficiency of vitamin D was found and the treatment was initiated. During the sec-ond hospitalization, biochemical and radiological investigations were per-formed to establish the diagnosis. Numerous vertebral compression fractures were dis-covered which were not re-vealed in the imaging investigations performed two years earli-er. She underwent symptomatic and appropriate medical rehabilitation treatment. Results and discussion: The evolution was fa-vorable after the hospitalization period, with a decrease in pain and functional deficit, as well as walking improvement. After endocrinological consultation it was decided to initiate therapy with Teriparatide which can decrease the risk of future fractures and reduce the back pain. Con-clusions: Adequate and prompt treatment of vitamin D deficiency and osteoporosis is very im-portant to avoid vertebral compression fractures or other complications of this disease. Physical and rehabilitation medicine also plays an important role in management of these patients.

Long non-coding RNA KCNQ1OT1 alleviates postmenopausal osteoporosis by modulating miR-421-3p/mTOR axis

The prevention and treatment of postmenopausal osteoporosis (PMOP) is a significant public health issue, and non-coding RNAs are of vital importance in this process. In this study, we find that the long non-coding RNA potassium voltage-gated channel subfamily Q member 1 overlapping transcript 1 (lncRNA KCNQ1OT1) can alleviate the ovariectomy-induced (OVX) PMOP in vivo. We determined that over-expression of KCNQ1OT1 could enhance functions of MC3T3-E1 cells, whereas an opposite trend was observed when KCNQ1OT1 was knocked down. Subsequently, miR-421-3p targeting KCNQ1OT1 was detected through a database search, and RNA fluorescent in situ hybridization, RNA immunoprecipitation, dual luciferase reporter assays all verified this relationship. Notably, KCNQ1OT1 stifled the miR-421-3p expression. The inhibition of proliferation, migration, and osteogenic differentiation caused by KCNQ1OT1 knock-down were reversed by an miR-421-3p inhibitor, further confirming the above findings. We verified that miR-421-3p specifically targeted the mammalian target of rapamycin (mTOR), and miR-421-3p inhibitor could reverse the negative effects of small interfering RNA of mTOR (si-mTOR) on MC3T3-E1 cells. Finally, osteoblasts isolated and cultured from OVX mice model and control mice also confirmed the observed trend. In combination, results mentioned above reveal that KCNQ1OT1 regulates MC3T3-E1 cell functions by regulating the miR-421-3p/mTOR axis.

Association between total cholesterol and total bone mineral density in US adults: National Health and Nutrition Examination Survey (NHANES), 2011-2018

BACKGROUND

Accumulated evidence indicates that cholesterol is offensive to bone metabolism. Therefore, we examined the real-world study among total cholesterol and total bone mineral density (BMD). We investigated the relationship between total cholesterol and total BMD among 10,039 US participants aged 20-59 years old over the period 2011-2018 from the NHANES.

METHODS

To analyze the relationship among total cholesterol and total BMD, multivariate linear regression models were used. Fitted smoothing curves, generalized additive models, and threshold effect analysis were also conducted.

RESULTS

After adjusting for additional covariates, weighted multivariable linear regression models indicated total cholesterol concentration levels exhibited a negative relationship with total BMD, particularly among participants aged 20-29 years. Concerning subgroup analysis, stratified by gender, race/ethnicity and age group, the negative correlation of total cholesterol with total BMD dwelled in both female and male as well as in whites and other races (including Hispanic and Multi-Racial), but not in non-Hispanic blacks and Mexican American. In other races, this relationship presented a nonlinear association (inflection point: 6.7 mmol/L) with a U-shaped curve. Among participants aged 40 to 49 years, this relationship also followed a nonlinear association (inflection point: 5.84 mmol/L), indicating a saturation effect. Moreover, the three types of diabetes status were found to have negative, U-shaped, and positive relationships. In participants with borderline diabetes status, the relationship of total cholesterol with total BMD was a U-shaped curve (inflection point: 4.65 mmol/L).

CONCLUSIONS

For US young adults (20-29 years old), our study revealed a negative relationship between total cholesterol and total BMD. This association followed a U-shaped curve (inflection point: 4.65 mmol/L) in borderline diabetes status participants, a saturation curve (inflection point: 5.84 mmol/L) in participants aged 40-49 years and a nonlinear curve (inflection point: 6.7 mmol/L) in other races (including Hispanic and Multi-Racial). Therefore, keeping total cholesterol concentration at a reasonable level for young adults and diabetic population might be an approach to prevent osteoporosis or osteopenia.

Identification and experimental validation of key m6A modification regulators as potential biomarkers of osteoporosis

Osteoporosis (OP) is a severe systemic bone metabolic disease that occurs worldwide. During the coronavirus pandemic, prioritization of urgent services and delay of elective care attenuated routine screening and monitoring of OP patients. There is an urgent need for novel and effective screening diagnostic biomarkers that require minimal technical and time investments. Several studies have indicated that N6-methyladenosine (m6A) regulators play essential roles in metabolic diseases, including OP. The aim of this study was to identify key m6A regulators as biomarkers of OP through gene expression data analysis and experimental verification. GSE56815 dataset was served as the training dataset for 40 women with high bone mineral density (BMD) and 40 women with low BMD. The expression levels of 14 major m6A regulators were analyzed to screen for differentially expressed m6A regulators in the two groups. The impact of m6A modification on bone metabolism microenvironment characteristics was explored, including osteoblast-related and osteoclast-related gene sets. Most m6A regulators and bone metabolism-related gene sets were dysregulated in the low-BMD samples, and their relationship was also tightly linked. In addition, consensus cluster analysis was performed, and two distinct m6A modification patterns were identified in the low-BMD samples. Subsequently, by univariate and multivariate logistic regression analyses, we identified four key m6A regulators, namely, METTL16, CBLL1, FTO, and YTHDF2. We built a diagnostic model based on the four m6A regulators. CBLL1 and YTHDF2 were protective factors, whereas METTL16 and FTO were risk factors, and the ROC curve and test dataset validated that this model had moderate accuracy in distinguishing high- and low-BMD samples. Furthermore, a regulatory network was constructed of the four hub m6A regulators and 26 m6A target bone metabolism-related genes, which enhanced our understanding of the regulatory mechanisms of m6A modification in OP. Finally, the expression of the four key m6A regulators was validated in vivo and in vitro, which is consistent with the bioinformatic analysis results. Our findings identified four key m6A regulators that are essential for bone metabolism and have specific diagnostic value in OP. These modules could be used as biomarkers of OP in the future.

Neutrophil-lymphocyte ratio as a risk factor for osteoporotic vertebrae fractures and femoral neck fractures

Fracture is associated with osteopenia after osteoporosis. Neutrophil-lymphocyte ratio (NLR) is common in inflammatory diseases. NLR can be used as an effective clinical tool to assess postmenopausal osteoporosis. The aim of this study is to further explore the relationship between elevated NLR and the severity of osteoporotic vertebrae fractures and femoral neck fracture based on magnetic resonance imaging (MRI). A total of 80 patients with osteoporotic vertebrae fractures, osteoporotic femoral neck fracture in Baoding Second Central Hospital from 2017 to 2020 were selected as the research objects. This study included a series of pretreatment factors, mainly including white blood cell count, red blood cell count, hemoglobin, and the general condition of the patients. Statistical methods included Pearson chi-square test, Spearman correlation test, logistic regression analysis and receiver operator characteristic (ROC) curve. According to Pearson chi-square test, Spearman correlation test, univariate/multivariate logistic regression analysis, the severity of osteoporotic vertebrae fractures, osteoporotic femoral neck fracture was significantly correlated with NLR (P < .001). NLR (odds ratio [OR] = 13.229, 95% CI: 4.167-41.998, P < .001) was a significant independent risk factor for osteoporotic vertebrae fractures, osteoporotic femoral neck fracture. receiver operator characteristic (ROC) curve was used to detect the specificity and sensitivity. The level of NLR has an important influence on the severity of osteoporotic vertebrae fractures and femoral neck fracture. The higher the level of NLR, the more serious the osteoporotic vertebrae fractures and femoral neck fracture.

Utilizing Graphical Analysis of Chest Radiographs for Primary Screening of Osteoporosis

Background and Objectives: Osteoporosis is a major risk of fractures, harming patients’ quality of life. Dual-energy X-ray absorptiometry (DXA), which can detect osteoporosis early, is too expensive to be conducted on a regular basis. Therefore, we aimed to evaluate a screening method using chest radiographs developed in Japan applied to another population. Materials and Methods: Fifty-five patients who had a chest radiograph and DXA and applied within three months of each test were recruited from the patient database of Semmelweis University (Budapest, Hungary). Graphical analysis of the chest radiographs was conducted to identify the ratio of the cortical bone in the clavicle of each patient. Two researchers performed the analysis, and multiple regression was conducted to determine the bone mineral density of each patient provided by DXA. Results: The Pearson correlation between two examiners’ determinations of the cortical bone ratio was 0.769 (p < 0.001). The multiple regression model proved to be statistically significant in identifying osteoporosis, but the model adopted for the Hungarian population was different compared to the Japanese population. Conclusions: This simple, economic Japanese graphical analysis method for chest radiographs may be feasible in detecting osteoporosis. Further studies with a larger population of patients with greater variety of ethnicity would be of value in improving the accuracy of this model.

Examining the role of cannabinoids on osteoporosis: a review

PURPOSE

Prior research studies have shown that the endocannabinoid system, influenced by CBD and THC, plays a role in bone remodeling. As both the research on cannabis and use of cannabis continue to grow, novel medicinal uses of both its constituents as well as the whole plant are being discovered. This review examines the role of cannabinoids on osteoporosis, more specifically, the endocannabinoid system and its role in bone remodeling and the involvement of the cannabinoid receptors 1 and 2 in bone health, as well as the effects of Δ9-tetrahydrocannabinol (THC), cannabidiol (CBD), and synthetic cannabinoids on bone.

METHODS

A comprehensive literature search of online databases including PUBMED was utilized.

RESULTS

A total of 29 studies investigating the effects of cannabis and/or its constituents as well as the activation or inactivation of cannabinoid receptors 1 and 2 were included and discussed.

CONCLUSION

While many of the mechanisms are still not yet fully understood, both preclinical and clinical studies show that the effects of cannabis mediated through the endocannabinoid system may prove to be an effective treatment option for individuals with osteoporosis.

A novel ceRNA regulatory network involving the long noncoding NEAT1, miRNA-466f-3p and its mRNA target in osteoblast autophagy and osteoporosis

Osteoporosis (OP) is a systemic metabolic disorder characterized by a reduction in bone tissue volume. LncRNAs have been reported to act as regulators of several human diseases. Specifically, lncRNA nuclear paraspeckle assembly transcript 1 (NEAT1) is involved in proliferation, differentiation and apoptosis in osteoclasts and bone marrow mesenchymal stem cells and regulates the occurrence and development of OP. However, the relationship between NEAT1 and osteoblast autophagy and its mechanism are still unclear. Western blotting of LC3 and P62 was used to evaluate the effect of fluid shear stress (FSS) on autophagy in MC3T3-E1 osteoblasts. Total transcriptome sequencing and bioinformatics analyses were performed on osteoblasts loaded with and without FSS. qPCR was performed to examine the expression of NEAT1 in OP bone tissues and osteoblasts. The RNA-FISH was performed to study the localization of lncRNA NEAT1 and miR-466f-3p in MC3T3-E1 osteoblasts. In vitro, western blotting, transmission electron microscopy (TEM), immunofluorescence (IF) staining and qPCR were performed to verify the biological functions of NEAT1, miR-466f-3p and HK2. Subsequently, we conducted bioinformatics analysis and dual luciferase reporter assays to identify the relationships among NEAT1, miR-466f-3p and HK2. Additionally, rescue assays were conducted on osteoblasts to clarify the regulatory network of the NEAT1/miR-466f-3p/HK2 signalling pathway. In vivo, the OVX mouse model was used to investigate the effects of si-NEAT1 on autophagy in OP mice. The distal femur and serum were collected for further micro-CT analysis, blood biochemistry, and haematoxylin-eosin and Alizarin red staining (ARS). Immunohistochemistry (IHC) was performed to assess the protein expression of LC3 and HK2. NEAT1 expression was upregulated in OP tissues and osteoblast lines exposed to FSS. Knockdown of NEAT1 inhibited autophagy in vitro and in vivo. Further studies demonstrated that NEAT1 positively regulated HK2 expression via its competing endogenous RNA effects on miR-466f-3p. Moreover, we found the NEAT1/miR-466f-3p/HK2 axis regulated autophagy in osteoblasts. Knocking down NEAT1 inhibited autophagy in osteoblasts via the miR-466f-3p/HK2 signalling pathway, which may provide new ideas for novel molecular therapeutic targets of postmenopausal OP. KEY MESSAGES: • Fluid shear stress (FSS) can promote autophagy of osteoblast and performed transcriptome sequencing. • NEAT1 is overexpressed in osteoporosis and could regulate osteoblast cells autophagy. • Knockdown of lncRNA NEAT1 inhibited osteoblast cells autophagy by sponging miRNA-466f-3p and targeting HK2 in osteoporosis.

The Therapeutic Potential of Plant Polysaccharides in Metabolic Diseases

Plant polysaccharides (PPS) composed of more than 10 monosaccharides show high safety and various pharmacological activities, including immunoregulatory, antitumor, antioxidative, antiaging, and other effects. In recent years, emerging evidence has indicated that many PPS are beneficial for metabolic diseases, such as cardiovascular disease (CVD), diabetes, obesity, and neurological diseases, which are usually caused by the metabolic disorder of fat, sugar, and protein. In this review, we introduce the common characteristics and functional activity of many representative PPS, emphasize the common risks and molecular mechanism of metabolic diseases, and discuss the pharmacological activity and mechanism of action of representative PPS obtained from plants including Aloe vera, Angelica sinensis, pumpkin, Lycium barbarum, Ginseng, Schisandra chinensis, Dioscorea pposite, Poria cocos, and tea in metabolic diseases. Finally, this review will provide directions and a reference for future research and for the development of PPS into potential drugs for the treatment of metabolic diseases.

Study on Risk Factors of Primary Non-traumatic OVCF in Chinese Elderly and a Novel Prediction Model

Objective

Prevention of fragility fractures is one of the public health priorities worldwide, whilst the incidence of osteoporotic vertebral compression fractures (OVCF) continues to rise and lacks the corresponding accurate prediction model. This study aimed to screen potential causes and risk factors for primary non‐traumatic osteoporotic vertebral compression fractures (NTOVCF) in the elderly by characterizing a patient population with NTOVCF and comparing it with a population of osteoporotic patients.

Methods

Between January 2013 and January 2022, 208 elderly patients with unequivocal evidence of bone fragility manifested as painful NTOVCF were enrolled, and compared with 220 patients with osteoporosis and no fractures. The demographic data, bone turnover markers, blood routine, serum biochemical values, and radiological findings were investigated. Differences between the fracture and non‐fracture groups were analyzed, and variables significant in univariate analysis and correlation analysis were included in the logistic analysis to build the risk prediction model for osteoporotic vertebral fractures. Univariate analysis using student's t‐tests for continuous variables or a chi‐squared test for categorical variables was conducted to identify risk factors.

Results

No significant differences were revealed regarding age, gender, BMI, smoking, alcohol consumption, blood glucose, propeptide of type I procollagen (P1NP), and N‐terminal middle segment osteocalcin (N‐MID) (P > 0.05). Parathyroid Hormone (PTH), 25(OH)D, serum albumin (ALB), hemoglobin (HB), bone mineral density (BMD), and cross‐sectional area (CSA) of the paraspinal muscle in the fracture group were significantly lower than those in the control group; however, b‐C‐terminal telopeptide of type I collagen (β‐CTX), total cholesterol (TC), high‐density lipoprotein cholesterol (HDL‐C), non‐prostatic acid phosphatase (NACP), and fatty degeneration ratio (FDR) were significantly higher than those in the control group (P < 0.05). Logistic regression analysis showed that ALB, HB, CSA, and BMD were negatively correlated with NTOVCF, while β‐CTX, HDL‐C, NACP, and FDR were positively correlated with NTOVCF.

Conclusion

Decreased physical activity, anemia, hypoproteinemia, imbalances in bone metabolism, abnormal lipid metabolism, and degenerative and decreased muscle mass, were all risk factors for OVCF in the elderly, spontaneous fractures may be the consequence of cumulative declines in multiple physiological systems over the lifespan. Based on this risk model, timely detection of patients with high OVCF risk and implementation of targeted preventive measures is expected to improve the effect of fracture prevention.

Chemical profiling and identification of anti-osteoporosis chemical-markers of Cinnamomum cassia (L.) presl extracts using GC-MS and spectrum-activity analyses

Cinnamomum cassia (L.) Presl (cinnamon), an important folk medicine is widely used to prevent osteoporosis for long time in China. Our study aimed to investigate the anti-osteoporosis activity and mechanisms of cinnamon extracts obtained by supercritical CO₂ extraction (SFE) and identify activity associated chemical components by gas chromatography-mass spectrometry. The cinnamon SFE exhibited superior anti-osteoporosis efficacy in an ovariectomised mice model to common alcohol extracts. It could induce calcified nodules and ALP activity, upregulate the mRNA expression of ALP, BMP-2, and RUNX2 in MC3T3-E1 cells. The major chemical classes of cinnamon extracts were alcohol esters (28.2%), and terpenes (16.1%). The spectrum-activity analysis indicated that the potential chemical-markers of extracts could be (E)-Cinnamaldehyde, γ-Sitosterol, and (Z, Z)-9,12-Octadecadienoic acid, which could induce the proliferation and ALP activity in MC3T3-E1 cells. Our study revealed the promising applications of the cinnamon SFE in prevention of osteoporosis, and identified its anti-osteoporosis associated compounds.

Inhibition of miR‑98‑5p promotes high glucose‑induced suppression of preosteoblast proliferation and differentiation via the activation of the PI3K/AKT/GSK3β signaling pathway by targeting BMP2

Osteoporosis (OP) is a bone metabolic disease, in which low bone mass and the microarchitectural deterioration of bone tissue contribute to the fragility of bones and increase the risk of fracture. The aim of the present study was to determine the role of microRNA (miR)-98-5p in high glucose (HG)-induced preosteoblasts. HG was used to induce preosteoblasts treated in a differentiation medium to establish an in vitro OP model. Next, miR-98-5p expression was determined using reverse transcription-quantitative PCR. Following the transfection of an miR-98-5p inhibitor into HG-treated osteoblasts, cell viability was assessed using a Cell Counting Kit-8 assay, while alkaline phosphatase (ALP) activity, differentiation ability and the expression of differentiation-regulated genes osteocalcin and osteopontin were measured using the corresponding ALP, Alizarin red staining, reverse transcription-quantitative PCR and western blotting assays. The association between miR-98-5p and the PI3K/AKT/GSK3β signaling pathway was determined using western blotting. Next, the binding relationship between miR-98-5p and bone morphogenetic protein 2 (BMP2) was predicted and verified, and the role of BMP2 in the regulation of the PI3K/AKT/GSK3β signaling pathway was explored using western blotting. The results revealed that miR-98-5p expression was upregulated in HG-induced osteoblasts, and the inhibition of miR-98-5p resulted in enhanced cell viability, alkaline phosphatase activity and differentiation in osteoblasts following HG induction. It was also discovered that miR-98-5p inhibition activated PI3K/AKT/GSK3β signaling, while knockdown of BMP2, which binds to miR-98-5p, enhanced the activation of this signaling pathway and the differentiation ability of osteoblasts. In conclusion, the findings of the present study suggested that the inhibition of miR-98-5p expression may activate PI3K/AKT/GSK3β signaling to promote HG-induced suppression of preosteoblast viability and differentiation by targeting BMP2, which provides a novel insight into future potential molecular markers for OP treatment.

Efficacy of Recombinant Human Parathyroid Hormone versus Vertebral Augmentation Procedure on Patients with Acute Osteoporotic Vertebral Compression Fracture

OBJECTIVE

Although widely used in clinical practice, vertebral augmentation procedure (VAP) for osteoporotic vertebral compression fracture (OVCF) is not supported. Recently, the effect of recombinant human parathyroid hormone (1-34) (rhPTH) has been paid great attention for its efficacy in anti-osteoporosis and bone union. This study aims to explore the outcome of rhPTH on acute OVCF and compare it with VAP to clarify its therapeutic advantages.

METHODS

The retrospective study comprised 71 acute OVCF patients from January 2015 to March 2020: 22 received rhPTH treatment (rhPTH group) and 49 underwent VAP (VAP group). The rhPTH group was 15 women and seven men with an average of 76.18 years, and the VAP group were 35 women and 14 men with an average of 73.63 years. The thoracic/lumbar vertebrae were 14/8 in the rhPTH group and 29/20 in the VAP group. The average follow-up period was 14.05 months in the rhPTH group and 13.82 months in the VAP group. The two groups were assessed regarding the visual analog score (VAS), Oswestry Disability Index (ODI), OVCF bone union, bone mineral density (BMD), kyphotic angle (KA), anterior and posterior border height (ABH and PBH, respectively), adverse events and the health-related quality of life assessed by short form-36 health survey scores (SF-36). Categorical variables were analyzed by chi-square test and continuous variables between groups were analyzed by independent samples t-test or Mann-Whitney U test according to the normality.

RESULTS

During the follow-up, the VAS was significantly lower in the rhPTH group than in the VAP group at month 3 (0.39 ± 0.6 vs 0.68 ± 0.651) (p = 0.047), month 6 (0.45 ± 0.60 vs 2.18 ± 1.22) (p < 0.001), and month 12 (0.45 ± 0.60 vs 2.43 ± 1.49) (p < 0.001). At month 12, the ODI was significantly lower in the rhPTH group (18.59 ± 3.33%) than in the VAP group (28.93 ± 16.71%) (p < 0.001). Bone bridge was detected on sagittal computed tomography images of all fractured vertebrae in the rhPTH group. The BMD was significantly higher in the rhPTH group (87.66 ± 5.91 Hounsfield units [HU]) than in the VAP group (68.15 ± 11.32HU) (p < 0.001). There were no significant differences in the changes in KA, ABH, and PBH between groups (all p > 0.05). The incidence of new OVCF was significantly lower in the rhPTH group than in the VAP group (p = 0.042). All scores of SF-36 were significantly higher in the rhPTH group than in the VAP group (all p < 0.05).

CONCLUSION

In acute OVCF patients, rhPTH was better than VAP in increasing spinal BMD to promote OVCF healing, reduce new OVCF, and improve back pain, physical ability, and health-related quality of life.

The association between coronary artery disease and osteoporosis: a population-based longitudinal study in Taiwan

PURPOSE

This large population-based study is the first to analyze the association between coronary artery disease (CAD) and osteoporosis (OP) from the National Health Insurance Research Database (NHIRD) in Taiwan to determine if CAD is associated with OP.

METHODS

Data from NHIRD, a national, population-based, retrospective, matched cohort study of 23 million patients, were collected to recruit two matched cohorts: with (n = 192,367) and without (n = 192,367) CAD. The Cox model was used to compare the incidence rate ratio and crude hazard ratio (HR) between the two cohorts for osteoporotic fracture and OP.

RESULTS

The CAD cohort had a significantly increased risk for vertebral compression fracture, with an adjusted HR of 1.74 (95% CI, 1.60-1.89). The cumulative incidence of OP was also statistically higher in the cohort versus without CAD (11.6% vs. 5.6%; p ≤ 0.0001, log-rank) during the 10-year follow-up period. The Cox model showed a 2.04-fold increase in the incidence of OP in the CAD cohort, with an adjusted HR of 2.04 (95% confidence interval [CI], 1.99-2.08).

CONCLUSIONS

A positive association exists between CAD and development of subsequent osteoporotic fracture and OP. Patients with CAD have a significantly increased risk of developing vertebral compression fracture and a higher incident rate ratio of OP.

TRIAL REGISTRATION

IRB approval number: No. C108094 on February 19, 2020.

Prevention and Treatment of Side Effects of Immunotherapy for Bladder Cancer

Bladder cancer (BC) is one of the most important tumors of the genitourinary system, associated with high morbidity and mortality rates. Over the years, various antitumor treatments have been developed, and immunotherapy is one of the most effective methods. Immunotherapy aims to activate the body’s immune system to kill cancer cells. It has been established that immunotherapy drugs can be classified into “non-targeted” and “targeted” drugs depending on their site of action. Immunotherapy is reportedly effective for BC. Even though it can attack cancer cells, it can also cause the immune system to attack healthy cells, which can occur at any time during treatment and sometimes even after immunotherapy is stopped. Importantly, different types of immunotherapies can cause different side effects. Side effects may manifest themselves as signs or as symptoms. The prevention and treatment of side effects caused by immunotherapy is an important part of cancer patient management.

The Role of Flavonoids in the Osteogenic Differentiation of Mesenchymal Stem Cells

Mesenchymal stem cells (MSCs) play an important role in developing bone tissue engineered constructs due to their osteogenic and chondrogenic differentiation potential. MSC-based tissue engineered constructs are generally considered a safe procedure, however, the long-term results obtained up to now are far from satisfactory. The main causes of these therapeutic limitations are inefficient homing, engraftment, and directional differentiation. Flavonoids are a secondary metabolite, widely existed in nature and have many biological activities. For a long time, researchers have confirmed the anti-osteoporosis effect of flavonoids through in vitro cell experiments, animal studies. In recent years the regulatory effects of flavonoids on mesenchymal stem cells (MSCs) differentiation have been received increasingly attention. Recent studies revealed flavonoids possess the ability to modulate self-renewal and differentiation potential of MSCs. In order to facilitate further research on MSCs osteogenic differentiation of flavonoids, we surveyed the literature published on the use of flavonoids in osteogenic differentiation of MSCs, and summarized their pharmacological activities as well as the underlying mechanisms, aimed to explore their promising therapeutic application in bone disorders and bone tissue engineered constructs.

Osteosarcopenia in autoimmune cholestatic liver diseases: Causes, management, and challenges

Primary biliary cholangitis and primary sclerosing cholangitis (PSC) are the most common cholestatic liver diseases (CLD) in adults and are both characterized by an immune pathogenesis. While primary biliary cholangitis is a model autoimmune disease, with over 90% of patients presenting very specific autoantibodies against mitochondrial antigens, PSC is considered an immune mediated disease. Osteoporosis is the most common bone disease in CLD, resulting in frequent fractures and leading to significant morbidity. Further, sarcopenia is emerging as a frequent complication of chronic liver diseases with a significant prognostic impact and severe implications on the quality of life of patients. The mechanisms underlying osteoporosis and sarcopenia in CLD are still largely unknown and the association between these clinical conditions remains to be dissected. Although timely diagnosis, prevention, and management of osteosarcopenia are crucial to limit the consequences, there are no specific guidelines for management of osteoporosis and sarcopenia in patients with CLD. International guidelines recommend screening for bone disease at the time of diagnosis of CLD. However, the optimal monitoring strategies and treatments have not been defined yet and vary among centers. We herein aim to comprehensively outline the pathogenic mechanisms and clinical implications of osteosarcopenia in CLD, and to summarize expert recommendations for appropriate diagnostic and therapeutic approaches.

A new Cu(II)-containing coordination polymer: protective effect and mechanism exploration on elderly osteoporotic hip fractures via regulating the wnt signaling pathway

Elderly osteoporosis hip fracture has drawn the attention of the researcher. The coordination polymer was now widely used in clinic because their multiple structures and biological activities. In this present research, the new coordination polymer was designed and synthesized and their application values on elderly osteoporosis hip were evaluated. The reaction between Cu(II) salt and 4,4'-(1H-1,2,4-triazol-1-yl)methylene-bis(benzoic acid) (H2tzmb), an aromatase inhibitor letrozole derivative with the aid of the organic linker 4,4-bipyridine (4,4'-bpy) affords a new coordination polymer based on Cu(II) ions as nodes of {[Cu2(tzmb)2(4,4'-bpy) (μ2-H2O)2(DMA) (H2O)2]·10DMA}n (1). The complex 1 gained is totally investigated with the powder X-ray diffraction study, thermogravimetric analyses, the diffraction of single-crystal X-ray, elemental analysis as well as the Fourier transform infrared spectrometer spectra. The osteogenic differentiation of mesenchymal stem cell was measured with the western blotting assay through determining the Runx2 expression. The wnt signaling pathway relative expression in mesenchymal stem cell was detected through the determination of real-time RT-PCR. The cytotoxicity of the compound on the mesenchymal stem cell was determined with CCK-8 assay. The result of single-crystal X-ray diffraction reflects that the complex 1 has crystallized in space group R-3c of trigonal system and exhibits a three-dimensional skeleton architecture on the bases of the SBUs {Cu(tzmb)(μ2-H2O)}n. The western blotting assay results revealed that this compound could significantly promote the osteogenic differentiation of mesenchymal stem cell. Besides, the activation of wnt signaling pathway in mesenchymal stem cell was also increased by the compound exposure. Finally, it can be summed up that this compound has excellent application values on the elderly osteoporotic hip fractures treatment by increasing the activation of wnt signaling pathway in mesenchymal stem cell. The results of the CCK-8 assay indicated that the compound has no cytotoxicity on the mesenchymal stem cell. The molecular docking simulation results have identified that only the carboxyl group on the Cu complex exhibits the activity for the hydrogen bond formation, however, the pyridine ring does not have such activity, instead, the pyridine ring only acts as the ligand that binds to the Cu ion. This Cu(II) coordination polymer has excellent application values on the elderly osteoporotic hip fractures treatment by increasing the activation of wnt signaling pathway in mesenchymal stem cell.

N,N-Dimethylformamide inhibits high glucose-induced osteoporosis via attenuating MAPK and NF-κB signalling

Aims

The role of N,N-dimethylformamide (DMF) in diabetes-induced osteoporosis (DM-OS) progression remains unclear. Here, we aimed to explore the effect of DMF on DM-OS development.

Methods

Diabetic models of mice, RAW 264.7 cells, and bone marrow macrophages (BMMs) were established by streptozotocin stimulation, high glucose treatment, and receptor activator of nuclear factor-κB ligand (RANKL) treatment, respectively. The effects of DMF on DM-OS development in these models were examined by micro-CT analysis, haematoxylin and eosin (H&E) staining, osteoclast differentiation of RAW 264.7 cells and BMMs, H&E and tartrate-resistant acid phosphatase (TRAP) staining, enzyme-linked immunosorbent assay (ELISA) of TRAP5b and c-terminal telopeptides of type 1 (CTX1) analyses, reactive oxygen species (ROS) analysis, quantitative reverse transcription polymerase chain reaction (qRT-PCR), Cell Counting Kit-8 (CCK-8) assay, and Western blot.

Results

The established diabetic mice were more sensitive to ovariectomy (OVX)-induced osteoporosis, and DMF treatment inhibited the sensitivity. OVX-treated diabetic mice exhibited higher TRAP5b and c-terminal telopeptides of type 1 (CTX1) levels, and DMF treatment inhibited the enhancement. DMF reduced RAW 264.7 cell viability. Glucose treatment enhanced the levels of TRAP5b, cathepsin K, Atp6v0d2, and H⁺-ATPase, ROS, while DMF reversed this phenotype. The glucose-increased protein levels were inhibited by DMF in cells treated with RANKL. The expression levels of antioxidant enzymes Gclc, Gclm, Ho-1, and Nqo1 were upregulated by DMF. DMF attenuated high glucose-caused osteoclast differentiation by targeting mitogen-activated protein kinase (MAPK) and nuclear factor kappa B (NF-κB) signalling in BMMs.

Conclusion

DMF inhibits high glucose-induced osteoporosis by targeting MAPK and NF-κB signalling.

Cite this article: Bone Joint Res 2022;11(4):200–209.

Epigallocatechin gallate attenuates tumor necrosis factor (TNF)-α-induced inhibition of osteoblastic differentiation by up-regulating lncRNA TUG1 in osteoporosis

Promoting osteoblast proliferation and differentiation contributes to the prevention and clinical treatment of osteoporosis. This study was to investigate the effect and mechanism of epigallocatechin gallate (EGCG) on tumor necrosis factor (TNF)-α-caused inhibition of osteoblastic differentiation. First, we cultured mouse embryo osteoblast precursor cells (MC3T3-E1) and induced by TNF-α (0, 2.5, 5, 10 ng/mL). The results revealed that TNF-α significantly inhibited the proliferation, ALP activity and mineralized nodule formation of MC3T3-E1 cells and promoted apoptosis. However, EGCG pretreatment significantly alleviated the inhibitory effect of TNF-α on MC3T3-E1. In addition, TNF-α significantly downregulated the expression of lncRNA TUG1 in MC3T3-E1, while EGCG upregulated the expression of lncRNA TUG1. After overexpression of lncRNA TUG1 in TNF-α-induced MC3T3-E1 cells, it could show similar effects as EGCG. However, interference with lncRNA TUG1 expression diminished the protective effect of EGCG on TNF-α-induced MC3T3-E1 cells. Finally, we found that EGCG inhibited TNF-α-induced activation of the Hippo/YAP signaling pathway, and that low expression of lncRNA TUG1 suppressed this effect. In conclusion, EGCG could suppress Hippo/YAP pathway activity by up-regulating lncRNA TUG1, ultimately improving TNF-α-caused inhibition of osteoblastic differentiation.

Patient-specific risk factors for adverse outcomes following geriatric proximal femur fractures

BACKGROUND

Proximal femur fractures (PFFs) occur frequently among geriatric patients due to diverse risk factors, such as a lower bone mineral density and the increased risk of falls.

METHODS

In this review, we focus on recent literature of patient-specific risk factors and their impact on common complications and outcome parameters in patients with PFF.

RESULTS

Patient- and treatment related factors have a significant impact on outcome and are associated with an increased risk of mortality, impairments in functional rehabilitation and complicative courses.

CONCLUSION

Geriatric patients at high risk for complications are nursing home inhabitants suffering from severe osteoporosis, dementia and sarcopenia. The early and ongoing assessment for these individual risk factors is crucial. Strategies including interdisciplinary approaches, addressing comorbidities and facilitating an optimal risk factor evaluation result in a beneficial outcome. The ongoing ambulant assessment and therapy of complicating factors (e.g., malnutrition, sarcopenia, frailty or osteoporosis) have to be improved.

Uncovering Hidden Mechanisms of Different Prescriptions Treatment for Osteoporosis via Novel Bioinformatics Model and Experiment Validation

Osteoporosis (OP) is a systemic disease susceptible to fracture due to the decline of bone mineral density and bone mass, the destruction of bone tissue microstructure, and increased bone fragility. At present, the treatments of OP mainly include bisphosphonates, hormone therapy, and RANKL antibody therapy. However, these treatments have observable side effects and cannot fundamentally improve bone metabolism. Currently, the prescription of herbal medicine and their derived proprietary Chinese medicines are playing increasingly important roles in the treatment of OP due to their significant curative effects and few side effects. Among these prescriptions, Gushukang Granules (GSK), Xianling Gubao Capsules (XLGB), and Er-xian Decoction (EXD) are widely employed at the clinic on therapy of OP, which also is in line with the compatibility principle of “different treatments for the same disease” in herbal medicine. However, at present, the functional interpretation of “different treatments for the same disease” in herbal medicine still lacks systematic quantitative research, especially on the detection of key component groups and mechanisms. To solve this problem, we designed a new bioinformatics model based on random walk, optimized programming, and information gain to analyze the components and targets to figure out the Functional Response Motifs (FRMs) of different prescriptions for the therapy of OP. The distribution of high relevance score, the number of reported evidence, and coverage of enriched pathways were performed to verify the precision and reliability of FRMs. At the same time, the information gain and target influence of each component was calculated, and the key component groups in all FRMs of each prescription were screened to speculate the potential action mode of different prescriptions on the same disease. Results show that the relevance score and the number of reported evidence of high reliable genes in FRMs were higher than those of the pathogenic genes of OP. Furthermore, the gene enrichment pathways in FRMs could cover 79.6, 81, and 79.5% of the gene enrichment pathways in the component-target (C-T) network. Functional pathway enrichment analysis showed that GSK, XLGB, and EXD all treat OP through osteoclast differentiation (hsa04380), calcium signaling pathway (hsa04020), MAPK signaling pathway (hsa04010), and PI3K-Akt signaling pathway (hsa04151). Combined with experiments, the key component groups and the mechanism of “different treatments for the same disease” in the three prescriptions and proprietary Chinese medicines were verified. This study provides methodological references for the optimization and mechanism speculation of Chinese medicine prescriptions and proprietary Chinese medicines.

Omentin‑1 induces osteoblast viability and differentiation via the TGF‑β/Smad signaling pathway in osteoporosis

Osteoporosis is a bone-related disease that results from impaired bone formation and excessive bone resorption. The potential value of adipokines has been investigated previously, due to their influence on osteogenesis. However, the osteogenic effects induced by omentin-1 remain unclear. The aim of the present study was to determine the regulatory effects of omentin-1 on osteoblast viability and differentiation, as well as to explore the underlying molecular mechanism. The present study investigated the effects of omentin-1 on the viability and differentiation of mouse pre-osteoblast cells (MC3T3-E1) using quantitative and qualitative measures. A Cell Counting Kit-8 assay was used to assess the viability of MC3T3-E1 cells following treatment with different doses of omentin-1. Omentin-1 and bone morphogenetic protein (BMP) inhibitor were added to osteogenic induction mediums in different ways to assess their effect. The alkaline phosphatase (ALP) activity and Alizarin Red S (ARS) staining of MC3T3-E1 cells treated with omentin-1 and/or BMP inhibitor were used to examine the effects of omentin-1 on differentiation and mineralization. Western blotting was used to further explore its potential mechanism, and to study the role of omentin-1 on the viability and differentiation of osteoblasts. The results showed that omentin-1 altered the viability of MC3T3-E1 cells in a dose-dependent manner. Omentin-1 treatment significantly increased the expression of members of the TGF-β/Smad signaling pathway. In the omentin-1 group, the ALP activity of the MC3T3-E1 cells was increased, and the ARS staining area was also increased. The mRNA and protein expression levels of BMP2, Runt-related transcription factor 2, collagen1, osteopontin, osteocalcin and osterix in the omentin-1 group were also significantly upregulated. All these effects were reversed following treatment with SIS3 HCl. These results demonstrated that omentin-1 can significantly promote osteoblast viability and differentiation via the TGF-β/Smad signaling pathway, thereby promoting bone formation and preventing osteoporosis.

The effects and mechanism of paeoniflorin in promoting osteogenic differentiation of MC3T3-E1

Background

The incidence of osteoporosis and osteoporotic fractures is increasing every year. Traditional Chinese Medicine (TCM) can shed new light on the treatment of osteoporosis. This study aimed to explore the role and mechanism of paeoniflorin in promoting osteogenic differentiation of an osteoblast precursor cell line (MC3T3-E1).

Methods

MC3T3-E1 cells were cultured in osteogenic induction medium (OIM) and OIM combined with different concentrations of paeoniflorin. The optimal dose of paeoniflorin was assessed by a cell counting kit-8 (CCK-8) assay. Then, alkaline phosphatase (ALP) and Alizarin Red S (ARS) staining were performed to assess the osteogenic capacity of paeoniflorin. The transcription of osteogenic genes and the expression of osteogenic proteins were assessed by RT-PCR and Western blotting, respectively. The transcription of Wnt/β-catenin signaling pathway genes and proteins was assessed by RT-PCR and Western blotting, respectively. Finally, Dickkopf-1 (DKK-1), a Wnt/β-catenin signaling pathway inhibitor, was used to identify whether the Wnt/β-catenin signaling pathway was involved in the osteogenic differentiation of paeoniflorin. Osteoclastogenesis in RAW264.7 cells was identified by tartrate-resistant acid phosphatase (TRAP) staining.

Results

At concentrations ranging from 0.1 to 100 μM, paeoniflorin was not cytotoxic to MC3T3-E1 cells. Paeoniflorin significantly increased the osteogenic differentiation of MC3T3-E1 cells in a dose-dependent manner. Moreover, paeoniflorin significantly increased osteogenic differentiation gene and protein expression. Through bioinformatic analysis, paeoniflorin-affected genes were found to be involved in different signaling pathways, such as the Wnt/β-catenin signaling pathway. Paeoniflorin enhanced β-catenin and CyclinD1 expression compared with that of the control groups. DKK-1 partially reversed the promoting effects of paeoniflorin in promoting osteogenic differentiation of MC3T3-E1 cells. Moreover, paeoniflorin inhibited the osteoclastogenesis of RAW264.7 cells.

Conclusion

Paeoniflorin promotes osteogenic differentiation in MC3T3-E1 cells by regulating the Wnt/β-catenin pathway. Paeoniflorin is a potential therapeutic agent for the treatment of osteoporosis.

Bioengineered Living Bone Grafts-A Concise Review on Bioreactors and Production Techniques In Vitro

It has been observed that bone fractures carry a risk of high mortality and morbidity. The deployment of a proper bone healing method is essential to achieve the desired success. Over the years, bone tissue engineering (BTE) has appeared to be a very promising approach aimed at restoring bone defects. The main role of the BTE is to apply new, efficient, and functional bone regeneration therapy via a combination of bone scaffolds with cells and/or healing promotive factors (e.g., growth factors and bioactive agents). The modern approach involves also the production of living bone grafts in vitro by long-term culture of cell-seeded biomaterials, often with the use of bioreactors. This review presents the most recent findings concerning biomaterials, cells, and techniques used for the production of living bone grafts under in vitro conditions. Particular attention has been given to features of known bioreactor systems currently used in BTE: perfusion bioreactors, rotating bioreactors, and spinner flask bioreactors. Although bioreactor systems are still characterized by some limitations, they are excellent platforms to form bioengineered living bone grafts in vitro for bone fracture regeneration. Moreover, the review article also describes the types of biomaterials and sources of cells that can be used in BTE as well as the role of three-dimensional bioprinting and pulsed electromagnetic fields in both bone healing and BTE.

Ataxia-televangelist mutated (ATM)/ ATR serine/threonine kinase (ATR)-mediated RAD51 recombinase (RAD51) promotes osteogenic differentiation and inhibits osteoclastogenesis in osteoporosis

Osteoporosis is a metabolic bone disease that significantly affects the quality of life and can even lead to death. In this study, we aimed to investigate the role of RAD51 recombinase (RAD51) in osteoblast and osteoclast differentiation. We analyzed differentially expressed genes using microarray analysis. The osteogenic differentiation capability was analyzed by alkaline phosphatase (ALP) staining and alizarin red staining assays. Osteogenesis and osteoclast related genes expression was detected using quantitative real-time PCR (qPCR) and Western blotting. The phosphorylation of Ataxia-telangiectasia mutated (ATM) and ATR serine/threonine kinase (ATR) was tested using Western blotting. The effect of RAD51 on osteoporosis was also explored in vivo. The results showed that RAD51 was downregulated in osteoporosis, but upregulated in differentiated osteoblasts. Overexpression of RAD51 enhanced the differentiation of osteoblasts and suppressed the formation of osteoclasts. Furthermore, p-ATM and p-ATR levels were upregulated in osteoblasts and downregulated in osteoclasts. RAD51 expression was reduced by the ATM/ATR pathway inhibitor AZ20. AZ20 treatment inhibited osteoblastogenesis and promoted osteoclastogenesis, whereas RAD51 reversed the effects induced by AZ20. Moreover, RAD51 improved bone microarchitecture in vivo. Taken together, ATM/ATR signaling-mediated RAD51 promoted osteogenic differentiation and suppressed osteoclastogenesis. These findings reveal a critical role for RAD51 in osteoporosis.

A Comprehensive Review of the Therapeutic Value of Urine-Derived Stem Cells

Stem cells possess regenerative powers and multidirectional differentiation potential and play an important role in disease treatment and basic medical research. Urine-derived stem cells (USCs) represent a newly discovered type of stem cell with biological characteristics similar to those of mesenchymal stromal cells (MSCs), including their doubling time and immunophenotype. USCs are noninvasive and can be readily obtained from voided urine and steadily cultured. Based on advances in this field, USCs and their secretions have increasingly emerged as ideal sources. USCs may play regulatory roles in the cellular immune system, oxidative stress, revascularization, apoptosis and autophagy. This review summarizes the applications of USCs in tissue regeneration and various disease treatments. Furthermore, by analysing their limitations, we anticipate the development of more feasible therapeutic strategies to promote USC-based individualized treatment.

CircRNA_0001795 sponges miRNA-339-5p to regulate yes-associated protein 1 expression and attenuate osteoporosis progression

Osteoporosis (OP) is one of the most common bone diseases, especially in women after menopause. Increasing evidence shows that non-coding RNAs are implicated in the pathogenesis of OP. In this study, based on the published circular RNA profiling data between OP patients and healthy controls, we found that circRNA_0001795 (circ_0001795) is downregulated in OP samples, which was further validated in the OP samples collected in this study. We therefore investigated the functional role and molecular mechanism of circ_0001795 in the osteogenic differentiation of human bone marrow stromal cells (hBMSCs) hBMSCs by alkaline phosphatase (ALP) activity assay, ALP and Alizarin Red S (ALS) Staining, luciferase reporter assay. Our data revealed that the overexpression of circ_0001795 could significantly promote the osteogenic differentiation of hBMSCs. MiRNA-339-5p (miR-339-5p) was identified as a target of circ_0001795, and miR-339-5p mimic attenuated the effect of circ_0001795 overexpression. MiR-339-5p downregulated yes-associated protein 1 (YAP1), which mediates the effect of circ_0001795 overexpression. Overall, this study uncovered the role of circ_0001795/miR-339-5p/YAP1 axis in regulating osteogenic differentiation, indicating that targeting Circ_0001795 could serve as a novel therapeutic target for OP.

lncRNA Kcnq1ot1 promotes bone formation by inhibiting miR‑98‑5p/Tbx5 axis in MC3T3‑E1 cells

Long non-coding (lnc)RNA KCNQ1 opposite strand/antisense transcript 1 (Kcnq1ot1) has been shown to regulate multiple biological processes. However, the functional role of Kcnq1ot1 in osteoporosis and the underlying mechanism are still unclear. The present study aimed to investigate the function of lncRNA Kcnq1ot1 in osteogenic differentiation. Alkaline phosphatase (ALP) activity was measured using an ALP assay kit. Western blotting was performed to assess the expression levels of osteogenic differentiation-associated proteins. Reverse transcription-quantitative PCR was performed to detect Kcnq1ot1, microRNA (miR)-98-5p and T-box transcription factor 5 (Tbx5) expression levels. The binding of Kcnq1ot1 with miR-98-5p and that of miR-98-5p with Tbx5 were predicted by starBase and TargetScan databases, respectively, and verified using dual luciferase reporter assays. The mineralization of MC3T3-E1 cells was observed using an Alizarin red S staining assay. The results revealed that expression of Kcnq1ot1 was increased and that of miR-98-5p was decreased during osteogenic differentiation. Additionally, Kcnq1ot1 was shown to target miR-98-5p and inhibit its expression. Inhibiting miR-98-5p reversed the inhibitory effect of Kcnq1ot1 knockdown on osteogenic differentiation and mineralization of MC3T3-E1 cells. Furthermore, Kcnq1ot1 regulated Tbx5 expression via miR-98-5p. Overexpressing miR-98-5p or downregulating Tbx5 expression reversed the promotive effect of Kcnq1ot1 overexpression on osteogenic differentiation and mineralization of MC3T3-E1 cells. In conclusion, these findings suggested that Kcnq1ot1 may promote bone formation by inhibiting miR-98-5p and upregulating Tbx5. Kcnq1ot1, miR-98-5p and Tbx5 may therefore serve as promising targets for the treatment of osteoporosis.

Associations of incidental vertebral fractures and longitudinal changes of MR-based proton density fat fraction and T2* measurements of vertebral bone marrow

BACKGROUND

Quantitative magnetic resonance imaging (MRI) techniques such as chemical shift encoding-based water-fat separation techniques (CSE-MRI) are increasingly applied as noninvasive biomarkers to assess the biochemical composition of vertebrae. This study aims to investigate the longitudinal change of proton density fat fraction (PDFF) and T2* derived from CSE-MRI of the thoracolumbar vertebral bone marrow in patients that develop incidental vertebral compression fractures (VCFs), and whether PDFF and T2* enable the prediction of an incidental VCF.

METHODS

In this study we included 48 patients with CT-derived bone mineral density (BMD) measurements at baseline. Patients that presented an incidental VCF at follow up (N=12, mean age 70.5 ± 7.4 years, 5 female) were compared to controls without incidental VCF at follow up (N=36, mean age 71.1 ± 8.6 years, 15 females). All patients underwent 3T MRI, containing a significant part of the thoracolumbar spine (Th11-L4), at baseline, 6-month and 12 month follow up, including a gradient echo sequence for chemical shift encoding-based water-fat separation, from which PDFF and T2* maps were obtained. Associations between changes in PDFF, T2* and BMD measurements over 12 months and the group (incidental VCF vs. no VCF) were assessed using multivariable regression models. Mixed-effect regression models were used to test if there is a difference in the rate of change in PDFF, T2* and BMD between patients with and without incidental VCF.

RESULTS

Prior to the occurrence of an incidental VCF, PDFF in vertebrae increased in the VCF group (Δ_PDFF=6.3 ± 3.1%) and was significantly higher than the change of PDFF in the group without VCF (Δ_PDFF=2.1 ± 2.5%, P=0.03). There was no significant change in T2* (Δ_T2*=1.7 ± 1.1ms vs. Δ_T2*=1.1 ± 1.3ms, P=0.31) and BMD (Δ_BMD=-1.2 ± 11.3mg/cm³ vs. Δ_BMD=-11.4 ± 24.1mg/cm³, P= 0.37) between the two groups over 12 months. At baseline, no significant differences were detected in the average PDFF, T2* and BMD of all measured vertebrae (Th11-L4) between the VCF group and the group without VCF (P=0.66, P=0.35 and P= 0.21, respectively). When assessing the differences in rates of change, there was a significant change in slope for PDFF (2.32 per 6 months, 95% confidence interval (CI) 0.31-4.32; P=0.03) but not for T2* (0.02 per 6 months, CI -0.98-0.95; P=0.90) or BMD (-4.84 per 6 months, CI -23.4-13.7; P=0.60).

CONCLUSIONS

In our study population, the average change of PDFF over 12 months is significantly higher in patients that develop incidental fractures at 12-month follow up compared to patients without incidental VCF, while T2* and BMD show no significant changes prior to the occurrence of the incidental vertebral fractures. Therefore, a longitudinal increase in bone marrow PDFF may be predictive for vertebral compression fractures.

Application of metabolomics in osteoporosis research

Osteoporosis (OP) is a systemic disease characterized by bone metabolism imbalance and bone microstructure destruction, which causes serious social and economic burden. At present, the diagnosis and treatment of OP mainly rely on imaging combined with drugs. However, the existing pathogenic mechanisms, diagnosis and treatment strategies for OP are not clear and effective enough, and the disease progression that cannot reflect OP further restricts its effective treatment. The application of metabolomics has facilitated the study of OP, further exploring the mechanism and behavior of bone cells, prevention, and treatment of the disease from various metabolic perspectives, finally realizing the possibility of a holistic approach. In this review, we focus on the application of metabolomics in OP research, especially the newer systematic application of metabolomics and treatment with herbal medicine and their extracts. In addition, the prospects of clinical transformation in related fields are also discussed. The aim of this study is to highlight the use of metabolomics in OP research, especially in exploring the pathogenesis of OP and the therapeutic mechanisms of natural herbal medicine, for the benefit of interdisciplinary researchers including clinicians, biologists, and materials engineers.

Knockdown of long non-coding RNA HOTAIR promotes bone marrow mesenchymal stem cell differentiation by sponging microRNA miR-378g that inhibits nicotinamide N-methyltransferase

Osteoporosis (OP) is associated with a serious social and economic burden. Recent studies have shown that the differential expression of long non-coding RNAs (lncRNAs) is closely related to OP. However, the specific molecular mechanism of HOX transcript antisense intergenic RNA (HOTAIR) remains to be elucidated.The expression of HOTAIR and miR-378g in OP patients was detected using quantitative reverse transcription polymerase chain reaction (qRT-PCR). Bone marrow mesenchymal stem cells (BMSCs) were isolated and cultured, and osteogenic differentiation was induced. Alkaline phosphatase (ALP) and Runt-related transcription factor 2 (RUNX2) were detected by qRT-PCR, ELISA, and Western blotting. Calcium deposition was measured using Alizarin red s (ARS) staining. Molecular interactions between HOTAIR, miR-378g, and nicotinamide N-methyltransferase (NNMT) were detected using a dual-luciferase reporter assay.HOTAIR expression was upregulated and miR-378g level was downregulated in OP patients. HOTAIR expression decreased during the osteogenic differentiation of BMSCs. Silencing HOTAIR or NNMT reduced ALP and RUNX2 levels and promoted calcium deposition. The overexpression of HOTAIR or interference with miR-378g inhibited the osteogenic differentiation of BMSCs. HOTAIR negatively regulates miR-378g by targeting NNMT.HOTAIR is an miR-378g sponge that targets NNMT, inhibits the osteogenic differentiation of BMSCs, and provides a valuable target for the treatment of OP.

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.

Psoas muscle index predicts osteoporosis and fracture risk in individuals with degenerative spinal disease

OBJECTIVES

Skeletal muscle loss and osteoporosis are major medical and socioeconomic concerns as the global population ages. Studies have reported that skeletal muscle mass correlates to bone mineral density (BMD). The psoas muscle index (PMI), measured as the L3 cross-sectional areas of the right and left psoas divided by the square of height, has a positive correlation with the total volume of skeletal muscle in the body. This study aimed to evaluate relationships between PMI and BMD and fracture risk estimated by the Fracture Risk Assessment Tool (FRAX).

METHODS

Preoperatively acquired, plain computed tomography images at the L3 level were used to measure PMI in 87 people with degenerative spinal diseases. We evaluated the correlation between PMI and BMD and fracture risk estimated by FRAX.

RESULTS

PMI was significantly correlated with BMD in the entire lumbar spine and femoral neck (r = 0.413 and 0.525, both P < 0.001). People with osteoporosis showed significantly lower PMI than those without (P < 0.05). PMI was also significantly correlated with FRAX score (r = -0.545, P < 0.001). Furthermore, based on the recommendation of osteoporosis treatment, participants were divided into two groups: FRAX ≥15% (R group) and FRAX <15% (C group). The R group showed significantly lower PMI than the C group (P < 0.001). Receiver operating characteristic curve analysis revealed that PMI has moderate accuracy in diagnosing osteoporosis and FRAX ≥15%.

CONCLUSIONS

PMI was significantly associated with BMD and fracture risk. PMI measurement is straightforward and may increase the diagnosis rate of osteoporosis and fracture risk.

LINC00370 modulates miR-222-3p-RGS4 axis to protect against osteoporosis progression

BACKGROUND

We aimed to determine the role of the LINC00370/miR-222-3p/RGS4 axis in modulating the process of adipose-derived stem cell (ADSC) osteogenic differentiation.

METHODS

We first evaluated the differential expression of LINC00370, miR-222-3p and RGS4 between normal and osteogenically induced ADSCs. Moreover, we transfected ADSCs with LINC00370 siRNA and an miR-222-3p inhibitor to determine the role of LINC00370 in modulating the process of ADSC osteogenic differentiation. Finally, we analyzed the dual-luciferase reporter gene to identify the relationship between LINC00370 and miR-222-3p. We first created osteoporotic rat models by ovariectomy (OVX) and treated with pcDNA-LINC00370. HE and immunohistochemical staining of OCN were performed to assess the changes in bone microarchitecture.

RESULTS

LINC00370 and RGS4 expression was remarkably upregulated in the osteogenic ADSC group compared with the normal medium group. On the other hand, miR-222-3p expression was remarkably decreased in the osteogenic group compared with the normal medium group. Knockdown of LINC00370 reduced the osteogenic differentiation of ADSCs. Moreover, the inhibitor of miR-222-3p partially reversed the reduction of osteogenic differentiation by LINC00370 knockdown. Knockdown of LINC00370 reduced the expression of p-Akt and p-PI3K. The inhibitor of miR-222-3p partially reversed the reduction of the expression of p-Akt and p-PI3K by LINC00370 knockdown. A dual luciferase reporter assay indicated that LINC00370 can directly bind miR-222-3p. LINC00370 suppressed OP progression in OVX and partially upregulated OCN protein expression.

CONCLUSION

Collectively, the above results confirm that LINC00370 promotes the process of ADSC osteogenic differentiation via the miR-222-3p/RGS4 axis. Moreover, LINC00370 could protect against OVX-induced OP.