An update on therapies for the treatment of diabetes-induced osteoporosis

RANKL/RANK contributes to the pathological process of type 2 diabetes mellitus through TRAF3 activation of NIK

Diabetic osteoporosis is a complication of diabetes mellitus (DM). Denosumab (DMB) is an effective anti-osteoporotic drug functions by inhibiting NF-κB ligand receptor-activating factor (RANKL). Previous study found that osteoprotegerin (OPG) regulated βcell homeostasis through the RNAK/RANKL pathway. The present study aimed to investigate the effect of RANKL/RANK on the pathological process of DM and the underlying mechanism. We used D-glucose-induced RINm5F cells to construct in vitro type 2 diabetes models (T2DM). A high-fat diet combined with intraperitoneal injection of streptozotocin (STZ) was used to establish a T2DM model in SD rats. The apoptosis of β-cells was determined by TdT-mediated dUTP nick-end labeling (TUNEL) analysis. qRT-PCR and western blotting assays were used to explore the mRNA and protein expression of the TRAF3 (Tumor necrosis factor receptor-associated factor)/NIK (NF-κB-inducible kinase) pathway. Furthermore, insulin expression was detected by ELISA and immunohistochemistry assay. The islet morphology was analyzed by H&E. In vivo experiments demonstrated that sRANKL-IN-3 down-regulated insulin secretion levels by significantly ameliorating pancreatic tissue damage and mitigating apoptosis of high glucose induced β-cells. Subsequently, sRANKL-IN-3, acting as an inhibitor of RANKL, mitigated functional decline in β-cells induced by high glucose, mainly manifested by the low expression of PDX-1 (pancreatic duodenal homeobox 1), BETA2 (beta-2 adrenoceptors), INS-1 (insulin 1), and INS-2 (insulin 2). Mechanistic studies revealed that deletion of TRAF3 combined with sRANKL-IN-3 administration reduced the activity of NIK, NF-κB2, and RelB in RINm5F cells. In addition, our study demonstrated that inhibition of either RANKL or TRAF3 had a protective effect on high glucose induced apoptosis. Moreover, the combined action of sRANKL-IN-3 and shTRAF3 had a more pronounced inhibitory effect on high glucose-induced apoptosis. In summary, RANKL/RANK deficiency may attenuate apoptosis of β-cells, a phenomenon associated with the TRAF3/NIK pathway. Therefore, RANKL/RANK could be regarded as a potential therapeutic strategy for DM.

LMK-235 suppresses osteoclastogenesis and promotes osteoblastogenesis by inhibiting HDAC4

Osteoblasts and osteoclasts play an important role in maintaining the structural integrity of bone tissue, in which osteoclasts degrade bone structure and osteoblasts restore bone tissue. The imbalance of osteoblast and osteoclast function can lead to many bone-related diseases, such as osteoporosis and inflammatory osteolysis. The drug that can both promote bone formation and inhibit bone loss will be able to treat those diseases. In this study, it was found that LMK-235, an selective HDAC4/5 inhibitor, inhibited the differentiation and maturation of osteoclasts by regulating NF-κB and p-Smad2/3 signaling pathways via inhibition of HDAC4. At the same time, we found that LMK-235 promoted osteoblast mineralization by upregulating Runx2 expression via inhibition of HDAC4. In vivo, LMK-235 was able to alleviate lipopolysaccharide (LPS)-induced calvarial osteolysis and promote the repair of bone defects. Taken together, LMK-235 suppresses osteoclast differentiation and promotes osteoblast formation by inhibiting HDAC4. This may provide a valuable treatment for bone diseases caused by abnormal osteoclast bone resorption and osteoblast bone regeneration.

Exploring the pharmacological mechanism of Xianlingubao against diabetic osteoporosis based on network pharmacology and molecular docking: An observational study

Xianlinggubao formula (XLGB), is a traditional Chinese compound Medicine that has been extensively used in osteoarthritis and aseptic osteonecrosis, but its curative effect on diabetic osteoporosis (DOP) and its pharmacological mechanisms remains not clear. The aim of the present study was to investigate the possible mechanism of drug repurposing of XLGB in DOP therapy. We acquired XLGB active compounds from the traditional Chinese medicine systems pharmacology and traditional Chinese medicines integrated databases and discovered potential targets for these compounds by conducting target fishing using the traditional Chinese medicine systems pharmacology and Swiss Target Prediction databases. Gene Cards and Online Mendelian Inheritance in Man® database were used to identify the DOP targets. Overlapping related targets between XLGB and DOP was selected to build a protein-protein interaction network. Next, the Metascape database was utilized to enrich the Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathways. In addition, Auto-Dock Vina software was used to verify drug and target binding. In total, 48 hub targets were obtained as the candidate targets responsible for DOP therapy. The anti-DOP effect mediated by XLGB was primarily centralized on the advanced glycation end products (AGEs)-receptor for AGE signaling pathway in diabetic complications and osteoclast differentiation. In addition, AKT serine/threonine kinase 1, tumor necrosis factor, Interleukin-6, vascular endothelial growth factor A and peroxisome proliferator activated receptor gamma, which were considered as potential therapeutic targets. Furthermore, molecular docking results confirm the credibility of the predicted therapeutic targets. This study elucidates that XLGB may through regulating AGEs formation and osteoclast differentiation as well as angiogenesis and adipogenesis against DOP. And this study provides new promising points to find the exact regulatory mechanisms of XLGB mediated anti-DOP effect.

Two-sample Mendelian randomization studies revealed a causal relationship between insulin use and osteoporosis: An observational study

OBJECTIVE

To investigate causal associations between diabetes, insulin treatment and osteoporosis using LDSC analysis with a 2-way Mendelian randomization study.

METHODS

LDSC analysis was used to estimate the likelihood-scale heritability of the genome-wide association study used with genetic correlation between the 2 genome-wide association study used. Then a 2-sample Mendelian randomization study was performed using 3 methods including inverse variance weighted, MR Egger, and weighted median.

RESULTS

The genetic correlation between diabetes, insulin treatment (h2_Z = 3.70, P = 2.16e-4), osteoporosis (h2_Z = 4.93, h2_p = 8.13e-7) and genes was significant. There was a significant genetic correlation (rg = 0.122, P = 0.0211). There was a causal association between diabetes, insulin treatment and osteoporosis [P = 0.003754, OR (95%CI) = 0.998876 (0.998116-0.999636)], while no causal association existed between osteoporosis and insulin use (P = 0.998116-0.999636) causal association existed (P = 0.333244).

CONCLUSION

There was a strong genetic correlation between diabetes, insulin treatment and osteoporosis, a causal association between diabetes, insulin treatment and osteoporosis, and no causal association between osteoporosis and diabetes, insulin treatment.

Association of serum trimethylamine N-oxide levels and bone mineral density in type 2 diabetes mellitus

PURPOSE

The relationship between trimethylamine N-oxide (TMAO) and bone mineral density (BMD) in type 2 diabetes mellitus (T2DM) is unclear. We explore the relationship between TMAO levels and BMD in T2DM.

METHODS

This is a cross-sectional study. 254 T2DM patients were enrolled and divided into three groups by TMAO tertiles, and the clinical data were collected. BMD was determined by dual-energy X-ray absorptiometry (DXA) and serum TMAO levels was determined by stable isotope dilution high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS).

RESULTS

Patients in the highest tertile of TMAO levels (TMAO > 6.72 μmol/L) showed relatively low BMD and a higher number of fracture history, osteoporosis (OP) than those in the lower tertiles. Spearman correlation analysis showed that serum TMAO was negatively correlated with BMD of whole body (WB), lumbar spine (LS) and femoral neck (FN), while TMAO was positive correlated with osteoporotic fracture (p < 0.05). Logistic regression models showed that TMAO was an independent influencing factor of fracture history after adjusting for confounders in TMAO > 6.72 μmol/L group.

CONCLUSIONS

There is a significant linear correlation between TMAO levels and BMD in T2DM patients. Especially in TMAO > 6.72 μmol/L group, TMAO was negatively correlated with WB, LS, and FN BMD, and was positive correlated with osteoporotic fracture in T2DM patients. The findings suggest that elevated TMAO levels are associated with OP and osteoporotic fracture in T2DM patients.

Harnessing GMNP-loaded BMSC-derived EVs to target miR-3064-5p via MEG3 overexpression: Implications for diabetic osteoporosis therapy in rats

Diabetic osteoporosis (DO) is a significant complication of diabetes, characterized by a decrease in bone mineral density and an increase in fracture risk. Magnetic nanoparticles (GMNPs) have emerged as potential drug carriers for various therapeutic applications. This study investigated the molecular mechanism of GMNPs loaded with bone marrow mesenchymal stem cell (BMSC) derived extracellular vesicles (EVs) overexpressing MEG3 target miR-3064-5p to induce NR4A3 for treating DO in rats. Initial analysis was carried out on GEO datasets GSE7158 and GSE62589, revealing a notable downregulation of NR4A3 in osteoporotic samples. Subsequent in vitro studies demonstrated the effective uptake of BMSC-EVs-MEG3 by osteoblasts and its potential to inhibit miR-3064-5p, activating the PINK1/Parkin signaling pathway and thus promoting mitochondrial autophagy, osteoblast proliferation, and differentiation. In vivo, experiments using DO rat models further substantiated the therapeutic efficacy of GMNPE-EVs-MEG3 in alleviating osteoporosis symptoms. In conclusion, GMNPs loaded with BMSC-EVs, through the delivery of MEG3 targeting miR-3064-5p, can effectively promote NR4A3 expression, activate the PINK1/Parkin pathway, and thereby enhance osteoblast proliferation and differentiation, offering a promising treatment for DO.

An ensemble-based machine learning model for predicting type 2 diabetes and its effect on bone health

BACKGROUND

Diabetes is a chronic condition that can result in many long-term physiological, metabolic, and neurological complications. Therefore, early detection of diabetes would help to determine a proper diagnosis and treatment plan.

METHODS

In this study, we employed machine learning (ML) based case-control study on a diabetic cohort size of 1000 participants form Qatar Biobank to predict diabetes using clinical and bone health indicators from Dual Energy X-ray Absorptiometry (DXA) machines. ML models were utilized to distinguish diabetes groups from non-diabetes controls. Recursive feature elimination (RFE) was leveraged to identify a subset of features to improve the performance of model. SHAP based analysis was used for the importance of features and support the explainability of the proposed model.

RESULTS

Ensemble based models XGboost and RF achieved over 84% accuracy for detecting diabetes. After applying RFE, we selected only 20 features which improved the model accuracy to 87.2%. From a clinical standpoint, higher HDL-Cholesterol and Neutrophil levels were observed in the diabetic group, along with lower vitamin B12 and testosterone levels. Lower sodium levels were found in diabetics, potentially stemming from clinical factors including specific medications, hormonal imbalances, unmanaged diabetes. We believe Dapagliflozin prescriptions in Qatar were associated with decreased Gamma Glutamyltransferase and Aspartate Aminotransferase enzyme levels, confirming prior research. We observed that bone area, bone mineral content, and bone mineral density were slightly lower in the Diabetes group across almost all body parts, but the difference against the control group was not statistically significant except in T12, troch and trunk area. No significant negative impact of diabetes progression on bone health was observed over a period of 5-15 yrs in the cohort.

CONCLUSION

This study recommends the inclusion of ML model which combines both DXA and clinical data for the early diagnosis of diabetes.

Geriatric nutritional risk index as a predictor for fragility fracture risk in elderly with type 2 diabetes mellitus: A 9-year ambispective longitudinal cohort study

BACKGROUND & AIMS

The elderly are prone to fragility fractures, especially those suffering from type 2 diabetes mellitus (T2DM) combined with osteoporosis. Although studies have confirmed the association between GNRI and the prevalence of osteoporosis, the relationship between GNRI and fragility fracture risk and the individualized 10-year probability of osteoporotic fragility fractures estimated by FRAX remains unclear. This study aims to delve into the association between the GNRI and a fragility fracture and the 10-year probability of hip fracture (HF) and major osteoporotic fracture (MOF) evaluated by FRAX in elderly with T2DM.

METHODS

A total of 580 patients with T2DM aged ≥60 were recruited in the study from 2014 to 2023. This research is an ambispective longitudinal cohort study. All participants were followed up every 6 months for 9 years with a median of 3.8 years through outpatient services, medical records, and home fixed-line telephone interviews. According to the tertiles of GNRI, all subjects were divided into three groups: low-level (59.72-94.56, n = 194), moderate-level (94.56-100.22, n = 193), and high-level (100.22-116.45, n = 193). The relationship between GNRI and a fragility fracture and the 10-year probability of HF and MOF calculated by FRAX was assessed by receiver operating characteristic (ROC) analysis, Spearman correlation analyses, restricted cubic spline (RCS) analyses, multivariable Cox regression analyses, stratified analyses, and Kaplan-Meier survival analysis.

RESULTS

Of 580 participants, 102 experienced fragile fracture events (17.59%). ROC analysis demonstrated that the optimal GNRI cut-off value was 98.58 with a sensitivity of 75.49% and a specificity of 47.49%, respectively. Spearman partial correlation analyses revealed that GNRI was positively related to 25-hydroxy vitamin D [25-(OH) D] (r = 0.165, P < 0.001) and bone mineral density (BMD) [lumbar spine (LS), r = 0.088, P = 0.034; femoral neck (FN), r = 0.167, P < 0.001; total hip (TH), r = 0.171, P < 0.001]; negatively correlated with MOF (r = -0.105, P = 0.012) and HF (r = -0.154, P < 0.001). RCS analyses showed that GNRI was inversely S-shaped dose-dependent with a fragility fracture event (P < 0.001) and was Z-shaped with the 10-year MOF (P = 0.03) and HF (P = 0.01) risk assessed by FRAX, respectively. Multivariate Cox regression analysis demonstrated that compared with high-level GNRI, moderate-level [hazard ratio (HR) = 1.950; 95% confidence interval (CI) = 1.076-3.535; P = 0.028] and low-level (HR = 2.538; 95% CI = 1.378-4.672; P = 0.003) had an increased risk of fragility fracture. Stratified analysis exhibited that GNRI was negatively correlated with the risk of fragility fracture, which the stratification factors presented in the forest plot were not confounding factors and did not affect the prediction effect of GNRI on the fragility fracture events in this overall cohort population (P for interaction > 0.05), despite elderly females aged ≥70, with body mass index (BMI) ≥24, hypertension, and with or without anemia (all P < 0.05). Kaplan-Meier survival analysis identified that the lower-level GNRI group had a higher cumulative incidence of fragility fractures (log-rank, all P < 0.001).

CONCLUSION

This study confirms for the first time that GNRI is negatively related to a fragility fracture and the 10-year probability of osteoporotic fragility fractures assessed by FRAX in an inverse S-shaped and Z-shaped dose-dependent pattern in elderly with T2DM, respectively. GNRI may serve as a valuable predictor for fragility fracture risk in elderly with T2DM. Therefore, in routine clinical practice, paying attention to the nutritional status of the elderly with T2DM and giving appropriate dietary guidance may help prevent a fragility fracture event.

ED-71 ameliorates bone regeneration in type 2 diabetes by reducing ferroptosis in osteoblasts via the HIF1α pathway

Eldecalcitol (ED-71), a novel active form of vitamin D, shows potential in treating osteoporosis. However, its underlying mechanisms of action remain to be determined. This study aimed to investigate the effect of ED-71 on bone regeneration and to illustrate its mode of action. The in-vitro model was developed using rat primary osteoblasts cultured under high-glucose conditions, and these cells were treated with ED-71. Additionally, an in vivo model of cranial bone defects was established in type 2 diabetic rats, and ED-71 was administered by gavage. The results demonstrated that ED-71 prevented osteoblast cell death, enhanced rat primary osteoblasts' osteogenic capacity, and attenuated the overexpression of hypoxia-inducible factor 1α (HIF1α) induced by high glucose levels. Furthermore, ED-71 increased glutathione peroxidase 4 (GPX4) levels and inhibited ferroptosis in response to hyperglycemic stimulation. Notably, interference with the HIF1α activator and ferroptosis activator Erastin significantly reduced the therapeutic effects of edetate osteolysis. These findings were further tested in vivo experiments. These results suggest that ED-71 activates the HIF1α pathway in vivo and in vitro, effectively relieving the ferroptosis induced by high glucose. Significantly, ED-71 may improve osteogenic disorders caused by diabetes.

Antidiabetic drug administration prevents bone mineral density loss: Evidence from a two-sample Mendelian randomization study

The aim of this study was to investigate the effect of common antidiabetic drugs on BMD by two-sample Mendelian randomization (MR). The single nucleotide polymorphisms that were strongly associated with insulin, metformin, rosiglitazone and gliclazide were extracted as instrumental variables (IVs) for MR analysis. The inverse variance weighted (IVW) method was used as the primary MR method to assess the causal effect of antidiabetic drugs on BMD, and other MR methods, including Weighted median, MR Egger and Weighted mode, were used for complementary analysis. Reliability and stability were assessed by the leave-one-out test. In the present work, IVW estimation of the causal effect of insulin on heel BMD demonstrated that there was a null effect of insulin on heel BMD (β = 0.765; se = 0.971; P = 0.430), while metformin treatment had a positive effect on heel BMD (β = 1.414; se = 0.460; P = 2.118*10-3). The causal relationship between rosiglitazone and heel BMD analysed by IVW suggested that there was a null effect of rosiglitazone on heel BMD (β = -0.526; se = 1.744; P = 0.763), but the causal effect of gliclazide on heel BMD evaluated by IVW demonstrated that there was a positive effect of gliclazide on heel BMD (β = 2.671; se = 1.340; P = 0.046). In summary, the present work showed that metformin and gliclazide have a role in reducing BMD loss in patients with diabetes and are recommended for BMD loss prevention in diabetes.

Establishment and validation of a nomogram clinical prediction model for osteoporosis in senile patients with type 2 diabetes mellitus

This study aimed to develop a predictive nomogram model to estimate the odds of osteoporosis (OP) in elderly patients with type 2 diabetes mellitus (T2DM) and validate its prediction efficiency. The hospitalized elderly patients with T2DM from the Affiliated Hospital of North Sichuan Medical University between July 2022 and March 2023 were included in this study. We sorted them into the model group and the validation group with a ratio of 7:3 randomly. The selection operator regression (LASSO) algorithm was utilized to select the optimal matching factors, which were then included in a multifactorial forward stepwise logistic regression to determine independent influencing factors and develop a nomogram. The discrimination, accuracy, and clinical efficacy of the nomogram model were analyzed utilizing the receiver operating characteristic (ROC) curve, calibration curve, and clinical decision curve analysis (DCA). A total of 379 study participants were included in this study. Gender (OR = 8.801, 95% CI 4.695-16.499), Geriatric Nutritional Risk Index (GNRI) < 98 (OR = 4.698, 95% CI 2.416-9.135), serum calcium (Ca) (OR = 0.023, 95% CI 0.003-0.154), glycated hemoglobin (HbA1c) (OR = 1.181, 95% CI 1.055-1.322), duration of diabetes (OR = 1.076, 95% CI 1.034-1.119), and serum creatinine (SCr) (OR = 0.984, 95% CI 0.975-0.993) were identified as independent influencing factors for DOP occurrence in the elderly. The area under the curve (AUC) of the nomogram model was 0.844 (95% CI 0.797-0.89) in the modeling group and 0.878 (95% CI 0.814-0.942) in the validation group. The nomogram clinical prediction model was well generalized and had moderate predictive value (AUC > 0.7), better calibration, and better clinical benefit. The nomogram model established in this study has good discrimination and accuracy, allowing for intuitive and individualized analysis of the risk of DOP occurrence in elderly individuals. It can identify high-risk populations and facilitate the development of effective preventive measures.

WITHDRAWN: Risk Factors for Early Subsidence of 3D Printed Artificial Vertebral After Anterior Cervical Corpectomy and Fusion

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Biochanin A abrogates osteoclastogenesis in type 2 diabetic osteoporosis via regulating ROS/MAPK signaling pathway based on integrating molecular docking and experimental validation

BACKGROUND

There are accumulating type 2 diabetes patients who have osteoporosis simultaneously. More effective therapeutic strategies should be discovered. Biochanin A (BCA) has been indicated that can play a role in improving metabolic disorders of type 2 diabetes and preventing osteoporosis. But whether BCA can treat type 2 diabetic osteoporosis has not been studied.

PURPOSE

To investigate if the BCA can protect against type 2 diabetic osteoporosis and clarify the mechanism.

METHODS

Micro-CT and histology assays were performed to detect the trabecular bone and analyze the bone histomorphology effect of BCA. CCK-8 assay was performed to detect the toxicity of BCA. TRAcP staining, immunofluorescence and hydroxyapatite resorption assay were used to observe osteoclasts differentiation and resorptive activity. Molecular docking provided evidence about BCA regulating the MAPK axis via prediction by the algorithm. QRT-PCR and Western Blotting were utilized to detect the expression of osteoclastogenesis-related markers and MAPK signaling pathway.

RESULTS

Accumulation of bone volume after BCA treatment could be found based on the 3D reconstruction. Besides, there were fewer osteoclasts in db/db mice treated with BCA than db/db mice treated with saline. In vitro, we found that BCA hadn't toxicity in osteoclasts precursor, but also inhibited differentiation of osteoclasts. Further, we found that BCA suppresses osteoclastogenesis via ROS/MAPK signaling pathway.

CONCLUSION

BCA can prevent type 2 diabetic osteoporosis by restricting osteoclast differentiation via ROS/MAPK signaling pathway.

The association between type 2 diabetes mellitus/prediabetes status and femoral neck bone mineral density in old adults

BACKGROUND

The prevalence of both type 2 diabetes mellitus (T2DM) and osteoporosis has been increasing among older individuals, with these two health conditions often coexisting. Our aim in this study was to evaluate the association between T2DM status and bone mineral density (BMD) of the femoral neck among older adults in the United States.

METHODS

This was a retrospective analysis of the data from 5695 adults, 60-80 years of age. The data were obtained from the National Health and Nutrition Examination Survey, for the following years: 2005-2006, 2007-2008, 2009-2010, 2013-2014, and 2017-2018. Weighted multivariable regression analyses, with subgroup analyses as appropriate, were performed to identify an association between T2DM/prediabetes status and femoral BMD and mediating factors.

RESULTS

There was a significant positive association between T2DM/prediabetes status and femoral neck BMD among older women, but not men, after adjusting for body mass index (BMI). On subgroup analysis, stratified by BMI, the significant positive association was retained for T2DM women with a BMI of 25-29.9 kg/m2 (β, 0.030; 95% CI, 0.007-0.052) or ≥30 kg/m2 (β, 0.029; 95% CI, 0.007-0.05), and for prediabetes women with a BMI of 25-29.9 kg/m2 (β, 0.016; 95% CI, 0.001-0.030).

CONCLUSIONS

The association between a positive T2DM/prediabetes status and femoral neck BMD differed by sex among older individuals, with the association being further modulated by BMI. For women with a BMI of 25-29.9 kg/m2 or ≥30 kg/m2, T2DM was associated with a significantly higher femoral neck BMD, compared to the non-diabetes group.

Insights into the underlying pathogenesis and therapeutic potential of endoplasmic reticulum stress in degenerative musculoskeletal diseases

Degenerative musculoskeletal diseases are structural and functional failures of the musculoskeletal system, including osteoarthritis, osteoporosis, intervertebral disc degeneration (IVDD), and sarcopenia. As the global population ages, degenerative musculoskeletal diseases are becoming more prevalent. However, the pathogenesis of degenerative musculoskeletal diseases is not fully understood. Previous studies have revealed that endoplasmic reticulum (ER) stress is a stress response that occurs when impairment of the protein folding capacity of the ER leads to the accumulation of misfolded or unfolded proteins in the ER, contributing to degenerative musculoskeletal diseases. By affecting cartilage degeneration, synovitis, meniscal lesion, subchondral bone remodeling of osteoarthritis, bone remodeling and angiogenesis of osteoporosis, nucleus pulposus degeneration, annulus fibrosus rupture, cartilaginous endplate degeneration of IVDD, and sarcopenia, ER stress is involved in the pathogenesis of degenerative musculoskeletal diseases. Preclinical studies have found that regulation of ER stress can delay the progression of multiple degenerative musculoskeletal diseases. These pilot studies provide foundations for further evaluation of the feasibility, efficacy, and safety of ER stress modulators in the treatment of musculoskeletal degenerative diseases in clinical trials. In this review, we have integrated up-to-date research findings of ER stress into the pathogenesis of degenerative musculoskeletal diseases. In a future perspective, we have also discussed possible directions of ER stress in the investigation of degenerative musculoskeletal disease, potential therapeutic strategies for degenerative musculoskeletal diseases using ER stress modulators, as well as underlying challenges and obstacles in bench-to-beside research.

AR/PCC herb pair inhibits osteoblast pyroptosis to alleviate diabetes-related osteoporosis by activating Nrf2/Keap1 pathway

Osteoporosis is a prevalent complication of diabetes, characterized by systemic metabolic impairment of bone mass and microarchitecture, particularly in the spine. Anemarrhenae Rhizoma/Phellodendri Chinensis Cortex (AR/PCC) herb pair has been extensively employed in Traditional Chinese Medicine to manage diabetes; however, its potential to ameliorate diabetic osteoporosis (DOP) has remained obscure. Herein, we explored the protective efficacy of AR/PCC herb pair against DOP using a streptozotocin (STZ)-induced rat diabetic model. Our data showed that AR/PCC could effectively reduce the elevated fasting blood glucose and reverse the osteoporotic phenotype of diabetic rats, resulting in significant improvements in vertebral trabecular area percentage, trabecular thickness and trabecular number, while reducing trabecular separation. Specifically, AR/PCC herb pair improved impaired osteogenesis, nerve ingrowth and angiogenesis. More importantly, it could mitigate the aberrant activation of osteoblast pyroptosis in the vertebral bodies of diabetic rats by reducing increased expressions of Nlrp3, Asc, Caspase1, Gsdmd and IL-1β. Mechanistically, AR/PCC activated antioxidant pathway through the upregulation of the antioxidant response protein Nrf2, while concurrently decreasing its negative feedback regulator Keap1. Collectively, our in vivo findings demonstrate that AR/PCC can inhibit osteoblast pyroptosis and alleviate STZ-induced rat DOP, suggesting its potential as a therapeutic agent for mitigating DOP.

Urine-derived stem cells-extracellular vesicles ameliorate diabetic osteoporosis through HDAC4/HIF-1α/VEGFA axis by delivering microRNA-26a-5p

Critical roles of stem cell-extracellular vesicles (EVs) in the management of osteoporosis have been documented. Here, this study was designed to enlarge the research of the specific effects and underlying mechanism of urine-derived stem cells-EVs (USCs-EVs) on osteoporosis in diabetes rats. Firstly, miR-26a-5p and histone deacetylase 4 (HDAC4) expression in USCs of rats after diabetic osteoporosis (DOP) modeling induced by streptozotocin injection was determined, followed by study of their interaction. Then, USCs-EVs were co-cultured with osteogenic precursor cells, the effects of miRNA-26a-5p (miR-26a-5p) on osteoblasts, osteoclasts, bone mineralization deposition rate were evaluated. Meanwhile, the effect of USCs-EVs carrying miR-26a-5p on DOP rats was assessed. Elevated miR-26a-5p was seen in USCs-EVs which limited HDAC4 expression. Moreover, USCs-EVs delivered miR-26a-5p to osteogenic precursor cells, thereby promoting their differentiation, enhancing the activity of osteoblasts, and inhibiting the activity of osteoclasts, thereby preventing DOP through the activation of hypoxia inducible factor 1 subunit alpha (HIF-1α)/vascular endothelial growth factor A (VEGFA) pathway by repressing HDAC4. In a word, USCs-EVs-miR-26a-5p is a promising therapy for DOP by activating HIF-1α/VEGFA pathway through HDAC4 inhibition. 1. USCs-EVs-miR-26a-5p targeted HDAC4 and limited HDAC4 expression. 2. miR-26a-5p was delivered by USCs-EVs into osteoblast precursor cells. 3. USCs-EVs-miR-26a-5p promoted the differentiation of osteoblast precursor cells into osteoblasts. 4. miR-26a-5p delivered by USCs-EVs could inhibit HDAC4. 5. USCs-EVs-miR-26a-5p could prevent the pathogenesis of DOP via HIF-1α/VEGFA aix.

Osteoporosis and diabetes - possible links and diagnostic difficulties

Objectives

In this review, the authors aimed to clarify the relationship between the occurrence of osteoporosis and diabetes, analyze the differences between the pathogenesis of osteoporosis in different types of diabetes and propose the most effective diagnostic strategy and fracture risk assessment in diabetic patients.

Material and methods

A analysis of publications in MEDLINE, COCHRANE and SCOPUS databases was performed, searching for reports on the diagnostics, fracture risk assessment, prevention, and treatment of osteoporosis in patients with diabetes mellitus (DM) published in the years 2016-2022. The key words for the search were: diabetes, osteoporosis, and low-energy fracture.

Results

Bone complications of T1DM are more severe than T2DM, because of the lack of anabolic effect of insulin on bones. In T2DM the risk of fractures is elevated; however, identifying the mechanisms underlying the increased risk of fractures in T2DM is not clear. The FRAX tool is not appropriate for assessing the fracture risk in young patients with T1DM. It is quite useful in older patients with T2DM, but in these patients the calculated fracture risk may be underestimated. In T2DM the fracture risk often does not correspond to BMD value as measured by dual-energy X-ray absorptiometry (DXA). Diagnostic tools such as the trabecular bone score may play a significant role in this group of patients. Conclusions: Optimal strategies to identify and treat high risk individuals require further research and proper definition. The diagnostic criteria for osteoporosis should be clearly defined as well as fracture risk assessment and choice of anti-osteoporotic medication. In all cases of secondary osteoporosis, treatment of the underlying disease is the most important. The relationship between high risk of fractures and diabetes is inseparable, and its full understanding seems to be the key to effective management.

The role of non-coding RNAs in diabetes-induced osteoporosis

Diabetes mellitus (DM) and osteoporosis are two major health care problems worldwide. Emerging evidence suggests that DM poses a risk for osteoporosis and can contribute to the development of diabetes-induced osteoporosis (DOP). Interestingly, some epidemiological studies suggest that DOP may be at least partially distinct from those skeletal abnormalities associated with old age or postmenopausal osteoporosis. The increasing number of DM patients who also have DOP calls for a discussion of the pathogenesis of DOP and the investigation of drugs to treat DOP. Recently, non-coding RNAs (ncRNAs) have received more attention due to their significant role in cellular functions and bone formation. It is worth noting that ncRNAs have also been demonstrated to participate in the progression of DOP. Meanwhile, nano-delivery systems are considered a promising strategy to treat DOP because of their cellular targeting, sustained release, and controlled release characteristics. Additionally, the utilization of novel technologies such as the CRISPR system has expanded the scope of available options for treating DOP. Hence, this paper explores the functions and regulatory mechanisms of ncRNAs in DOP and highlights the advantages of employing nanoparticle-based drug delivery techniques to treat DOP. Finally, this paper also explores the potential of ncRNAs as diagnostic DOP biomarkers.

Relationship between Cognitive Impairment and Depressive Symptoms with Somatosensory Functions in Diabetic and Non-Diabetic Older Adults and Its Impact on Quality of Life

Aging is an inevitable process that impacts the peripheral and central nervous systems and is considered one of the strongest risk factors for neurodegenerative diseases. In addition, when it also presents with diabetes mellitus, the risk of neurological damage may be further increased. This current study aimed to explore the relationships between peripheral sensory system decline and cognitive functions, the symptoms of depression, and quality of life (QoL) as metrics of central nervous system impairment in institutionalized older adults. A total of 95 individuals participated in this case-control study, which included diabetics and non-diabetics. The superficial sensory pathway was assessed in terms of thermal sensation, nociception, and non-discriminative touch, and the deep sensory pathway was evaluated by assessing vibration and light touch-pressure sensations. To assess function at the intellectual level, the Mini-Mental State Examination (MMSE) and Trail Making Test (TMT) cognitive functional tests were used, while the symptoms of depression and QoL were explored by employing the Yesavage Geriatric Depression Scale and EuroQol 5D questionnaire (EQ-5D), respectively. In the overall population analyses, altered thermal sensation was significantly associated with cognitive impairment (CI; p < 0.05). In turn, bivariate analyses and a binary logistic regression showed that the symptoms of depression and QoL were significantly related to altered vibratory sensation when assessed using a medical tuning fork (p < 0.05). In the group of diabetic patients, those with CI also had significantly lower thermal sensation (p < 0.05) and non-discriminative touch sensation, although this was only a trend (p = 0.055). Diabetics with depression had a significantly worse non-discriminative touch (p < 0.05) and vibratory sensation when tested with a tuning fork (p < 0.05). In addition, poorer QoL was associated with reduced sensitivity to heat (p < 0.05), light touch pressure (p < 0.05), and vibrations when assessed either with a tuning fork (p < 0.05) or a biothesiometer (p < 0.05). In contrast, no relationships were found between sensory functions and cognitive assessments in non-diabetic patients. These findings indicate that superficial sensitivity damage was related to CI, while deep sensation alterations were related to depression and poor QoL, with diabetes apparently further strengthening these relationships.

The Synergistic Effect of Zuogui Pill and Eldecalcitol on Improving Bone Mass and Osteogenesis in Type 2 Diabetic Osteoporosis

Background and Objectives: The incidence of diabetic osteoporosis, an important complication of diabetes mellitus, is increasing gradually. This study investigated the combined effect of the Zuogui pill (ZGP) and eldecalcitol (ED-71), a novel vitamin D analog, on type 2 diabetic osteoporosis (T2DOP) and explored their action mechanism. Materials and Methods: Blood glucose levels were routinely monitored in db/db mice while inducing T2DOP. We used hematoxylin and eosin staining, Masson staining, micro-computed tomography, and serum biochemical analysis to evaluate changes in the bone mass and blood calcium and phosphate levels of mice. Immunohistochemical staining was performed to assess the osteoblast and osteoclast statuses. The MC3T3-E1 cell line was cultured in vitro under a high glucose concentration and induced to undergo osteogenic differentiation. Quantitative real-time polymerase chain reaction, Western blot, immunofluorescence, ALP, and alizarin red staining were carried out to detect osteogenic differentiation and PI3K-AKT signaling pathway activity. Results: ZGP and ED-71 led to a dramatic decrease in blood glucose levels and an increase in bone mass in the db/db mice. The effect was strongest when both were used together. ZGP combined with ED-71 promoted osteoblast activity and inhibited osteoclast activity in the trabecular bone region. The in vitro results revealed that ZGP and ED-71 synergistically promoted osteogenic differentiation and activated the PI3K-AKT signaling pathway. The PI3K inhibitor LY294002 or AKT inhibitor ARQ092 altered the synergistic action of both on osteogenic differentiation. Conclusions: The combined use of ZGP and ED-71 reduced blood glucose levels in diabetic mice and promoted osteogenic differentiation through the PI3K-AKT signaling pathway, resulting in improved bone mass. Our study suggests that the abovementioned combination constitutes an effective treatment for T2DOP.

Extracellular vesicles derived from bone marrow mesenchymal stem cells loaded on magnetic nanoparticles delay the progression of diabetic osteoporosis via delivery of miR-150-5p

Extracellular vesicles derived from bone marrow mesenchymal stem cells (BMSC-EVs) are emerged as carriers of therapeutic targets against bone disorders, yet its isolation and purification are limited with recent techniques. Magnetic nanoparticles (MNPs) can load EVs with a unique targeted drug delivery system. We constructed gold-coated magnetic nanoparticles (GMNPs) by decorating the surface of the Fe3O4@SiO2 core and a silica shell with poly(ethylene glycol) (PEG)-aldehyde (CHO) and examined the role of BMSC-EVs loaded on GMNPs in diabetic osteoporosis (DO). The osteoporosis-related differentially expressed miR-150-5p was singled out by microarray analysis. DO models were then established in Sprague-Dawley rats by streptozotocin injection, where poor expression of miR-150-5p was validated in the bone tissues. Next, GMNPE was prepared by combining GMNPs with anti-CD63, after which osteoblasts were co-cultured with the GMNPE-BMSC-EVs. The re-expression of miR-150-5p facilitated osteogenesis in osteoblasts. GMNPE could promote the enrichment of EVs in the bone tissues of DO rats. BMSC-EVs delivered miR-150-5p to osteoblasts, where miR-150-5p targeted MMP14 and consequently activated Wnt/β-catenin pathway. This effect contributed to the enhancement of osteoblast proliferation and maturation. Furthermore, GMNPE enhanced the EV-based delivery of miR-150-5p to regulate the MMP14/Wnt/β-catenin axis, resulting in promotion of osteogenesis. Overall, our findings suggest the potential of GMNP-BMSC-EVs to strengthen osteoblast proliferation and maturation in DO, showing promise as an appealing drug delivery strategy against DO. 1. GMNPs-BMSCs-EVs-miR-150-5p promotes the osteogenesis of DO rats. 2. miR-150-5p induces osteoblast proliferation and maturation by targeting MMP14. 3. Inhibition of MMP14 activates Wnt/β-catenin and increases osteogenesis. 4. miR-150-5p activates the Wnt/β-catenin pathway by downregulating MMP14.

Dipeptidyl peptidase 3 is essential for maintaining osteoblastic differentiation under a high-glucose environment by inhibiting apoptosis, oxidative stress and inflammation through the modulation of the Keap1-Nrf2 pathway

Dipeptidyl peptidase 3 (Dpp3) has emerged as a pivotal mediator of bone homeostasis and bone loss pathology. However, whether Dpp3 plays a role in diabetic osteoporosis has not been addressed. Therefore, this work explored the possible role of Dpp3 in osteoblast dysfunction evoked by high glucose (HG), a cellular model for studying diabetic osteoporosis in vitro. Dpp3 expression was decreased in the pre-osteoblast MC3T3-E1 during osteoblastic differentiation under the HG environment. The osteoblastic differentiation impaired by HG was reversed in Dpp3-overexpressing MC3T3-E1 cells. The migration and invasion of MC3T3-E1 cells impeded by HG were reversed by Dpp3 overexpression. Moreover, HG-evoked apoptosis, oxidative stress and inflammation were ameliorated in Dpp3-overexpressing MC3T3-E1 cells. A mechanistic study showed that Dpp3 up-regulated the activation of nuclear factor E2-related factor 2 (Nrf2) depending on Kelch-like ECH-associated protein 1 (Keap1). The blockade of Nrf2 reversed Dpp3-mediated effects on osteoblastic differentiation, apoptosis, oxidative stress and inflammation of HG-stimulated MC3T3-E1 cells. Therefore, Dpp3 plays an essential role in maintaining osteoblastic differentiation under a HG environment associated with the regulation of the Keap1-Nrf2 pathway. This work indicates a possible relationship between Dpp3 and diabetic osteoporosis.

Type 2 diabetes mellitus plays a protective role against osteoporosis --mendelian randomization analysis

BACKGROUND

Type 2 diabetes mellitus (DM2) and osteoporosis (OP) are currently the two most significant causes of mortality and morbidity in older adults, according to clinical evidence. The intrinsic link between them is yet unknown, despite reports of their coexistence. By utilizing the two-sample Mendelian randomization (MR) approach, we sought to evaluate the causal impact of DM2 on OP.

METHODS

The aggregate data of the whole gene-wide association study (GWAS) were analyzed. A two-sample MR analysis was performed using single-nucleotide polymorphisms (SNPs), which are strongly associated with DM2, as instrumental variables (IVs) to evaluate the causal analysis of DM2 on OP risk with OR values, using inverse variance weighting, MR-egger regression, and weighted median methods, respectively.

RESULT

A total of 38 single nucleotide polymorphisms were included as tool variables. According to the results of inverse variance-weighted (IVW), we found that there was a causal relationship between DM2 and OP, in which DM2 had a protective effect on OP. For each additional case of DM2, there is a 0.15% decrease in the odds of developing OP (OR = 0.9985;95%confidence interval:0.9974,0.9995; P value = 0.0056). There was no evidence that the observed causal effect between DM2 and the risk of OP was affected by genetic pleiotropy (P = 0.299). Using Cochran Q statistics and MR-Egger regression in the IVW approach, the heterogeneity was calculated; P > 0.05 shows that there is a significant amount of heterogeneity.

CONCLUSION

A causal link between DM2 and OP was established by MR analysis, which also revealed that DM2 decreased the occurrence of OP.

RANKL inhibition: a new target of treating diabetes mellitus?

Accumulating evidence demonstrates the link between glucose and bone metabolism. The receptor activator of nuclear factor-kB ligand (RANKL)/the receptor activator of NF-κB (RANK)/osteoprotegerin (OPG) axis is an essential signaling axis maintaining the balance between bone resorption and bone formation. In recent years, it has been found that RANKL and RANK are distributed not only in bone but also in the liver, muscle, adipose tissue, pancreas, and other tissues that may influence glucose metabolism. Some scholars have suggested that the blockage of the RANKL signaling may protect islet β-cell function and prevent diabetes; simultaneously, there also exist different views that RANKL can improve insulin resistance through inducing the beige adipocyte differentiation and increase energy expenditure. Currently, the results of the regulatory effect on glucose metabolism of RANKL remain conflicting. Denosumab (Dmab), a fully human monoclonal antibody that can bind to RANKL and prevent osteoclast formation, is a commonly used antiosteoporosis drug. Recent basic studies have found that Dmab seems to regulate glucose homeostasis and β-cell function in humanized mice or in vitro human β-cell models. Besides, some clinical data have also reported the glucometabolic effects of Dmab, however, with limited and inconsistent results. This review mainly describes the impact of the RANKL signaling pathway on glucose metabolism and summarizes clinical evidence that links Dmab and DM to seek a new therapeutic strategy for diabetes.

P53 negatively regulates the osteogenic differentiation in jaw bone marrow MSCs derived from diabetic osteoporosis

Patients with diabetic osteoporosis (DOP) often suffer from poor osseointegration of artificial implants, which is a challenge that affects implant outcomes. The osteogenic differentiation ability of human jaw bone marrow mesenchymal stem cells (JBMMSCs) is the key to implant osseointegration. Studies have shown that the microenvironment of hyperglycemia affects the osteogenic differentiation of mesenchymal stem cells (MSC), but the mechanism is still unclear. Therefore, the aim of this study was to isolate and culture JBMMSCs from surgically derived bone fragments from DOP patients and control patients to investigate the differences in their osteogenic differentiation ability and to elucidate its mechanisms. The results showed that the osteogenic ability of hJBMMSCs was significantly decreased in the DOP environment. Mechanism study showed that the expression of senescence marker gene P53 was significantly increased in DOP hJBMMSCs compared to control hJBMMSCs according to RNA-sequencing result. Further, DOP hJBMMSCs were found to display significant senescence using β-galactosidase staining, mitochondrial membrane potential and ROS assay, qRT-PCR and WB analysis. Overexpression of P53 in hJBMMSCs, knockdown of P53 in DOP hJBMMSCs, and knockdown followed by overexpression of P53 significantly affected the osteogenic differentiation ability of hJBMMSCs. These results suggest that MSC senescence is an important reason for decreasing osteogenic capacity in DOP patients. P53 is a key target in regulating hJBMMSCs aging, and knocking down P53 can effectively restore the osteogenic differentiation ability of DOP hJBMMSCs and promote osteosynthesis in DOP dental implants. It provided a new idea to elucidate the pathogenesis and treatment of diabetic bone metabolic diseases.

Unlocking the Full Potential of SGLT2 Inhibitors: Expanding Applications beyond Glycemic Control

The number of diabetic patients has risen dramatically in recent decades, owing mostly to the rising incidence of type 2 diabetes mellitus (T2DM). Several oral antidiabetic medications are used for the treatment of T2DM including, α-glucosidases inhibitors, biguanides, sulfonylureas, meglitinides, GLP-1 receptor agonists, PPAR-γ agonists, DDP4 inhibitors, and SGLT2 inhibitors. In this review we focus on the possible effects of SGLT2 inhibitors on different body systems. Beyond the diabetic state, SGLT2 inhibitors have revealed a demonstrable ability to ameliorate cardiac remodeling, enhance myocardial function, and lower heart failure mortality. Additionally, SGLT2 inhibitors can modify adipocytes and their production of cytokines, such as adipokines and adiponectin, which enhances insulin sensitivity and delays diabetes onset. On the other hand, SGLT2 inhibitors have been linked to decreased total hip bone mineral deposition and increased hip bone resorption in T2DM patients. More data are needed to evaluate the role of SGLT2 inhibitors on cancer. Finally, the effects of SGLT2 inhibitors on neuroprotection appear to be both direct and indirect, according to scientific investigations utilizing various experimental models. SGLT2 inhibitors improve vascular tone, elasticity, and contractility by reducing oxidative stress, inflammation, insulin signaling pathways, and endothelial cell proliferation. They also improve brain function, synaptic plasticity, acetylcholinesterase activity, and reduce amyloid plaque formation, as well as regulation of the mTOR pathway in the brain, which reduces brain damage and cognitive decline.

Association between androgen receptor gene alteration and osteoporosis in Chinese Han elderly men

Objective

To explore the role of blood glucose, blood lipids, and androgen receptor gene (CAG)n genotype in the pathogenesis of osteoporosis in Chinese Han men and to provide theoretical value for screening people susceptible to osteoporosis.

Methods

Patients who visited the First Affiliated Hospital of Chengdu Medical College from February 2021 to October 2021 were selected as research subjects to measure bone density by double-energy X-ray, osteoporosis patients as osteoporosis group (40 patients), and non-osteoporosis patients as the control group (40 patients). The STR method detected the repeat times of the androgen receptor gene (CAG)n in the two groups. The repeat times ≤22 were the SS genotype, and >22 were the LL genotype. Meanwhile, the patient's age, body mass index (BMI), blood glucose, blood lipids, calcium, phosphorus, and alkaline phosphatase examined on day one after admission were collected, and the statistical analysis was performed using SPSS 26.0.

Results

The results of the univariate analysis showed that there was no significant difference in age, calcium, phosphorus, alkaline phosphatase, and glycosylated hemoglobin between the two groups (P > 0.05). There were significant differences in average blood glucose, total cholesterol, triglyceride, high-density lipoprotein, low-density lipoprotein, and genotype frequency (P < 0.05). The multivariate logistic regression analysis results showed significant differences in total cholesterol and genotype frequency between the two groups (P < 0.05).

Conclusion

Androgen receptor LL genotype and elevated total cholesterol may be the risk factors for osteoporosis in older men of Han nationality.

Sambucus williamsii Hance maintains bone homeostasis in hyperglycemia-induced osteopenia by reversing oxidative stress via cGMP/PKG signal transduction

BACKGROUND

Sambucus williamsii Hance (SWH) has effectively been adopted to treat joint and bone disorders. Diabetes-induced osteopenia (DOP) is caused primarily by impaired bone formation as a result of hyperglycemia. We had previously demonstrated that SWH extract accelerated fracture healing and promoted osteoblastic MC3T3-E1 cell proliferation and osteogenic differentiation. This study assessed the impacts of SWH extract on diabetes-induced bone loss and explored the mechanisms underlying its osteoprotective effects.

METHODS

This work employed MC3T3-E1 cell line for evaluating how SWH extract affected osteogenesis, oxidative stress (OS), and the underlying mechanism in vitro. Streptozotocin-induced osteopenia mouse model was applied with the purpose of assessing SWH extract's osteoprotection on bone homeostasis in vivo.

RESULTS

The increased OS of MC3T3-E1 cells exposed to high glucose (HG) was largely because of the upregulation of pro-oxidant genes and the downregulation of antioxidant genes, whereas SWH extract reduced the OS by modulating NADPH oxidase-4 and thioredoxin-related genes by activating cyclic guanosine monophosphate (cGMP) production and increasing the level of cGMP-mediated protein kinase G type-2 (PKG2). The oral administration of SWH extract maintained bone homeostasis in type 1 diabetes mellitus (T1DM) mice by enhancing osteogenesis while decreasing OS. In bones from hyperglycemia-induced osteopenia mice and HG-treated MC3T3-E1 cells, the SWH extract achieved the osteoprotective effects through activating the cGMP/PKG2 signaling pathway, upregulating the level of antioxidant genes, as well as downregulating the level of pro-oxidant genes.

CONCLUSION

SWH extract exerts osteoprotective effects on hyperglycemia-induced osteopenia by reversing OS via cGMP/PKG signal transduction and is a potential therapy for DOP.

Development and Validation of a Risk Nomogram Model for Predicting Constipation in Patients with Type 2 Diabetes Mellitus

Purpose

Constipation is a common complication of diabetic patients, which has a negative impact on their own health. This study aims to establish and internally validate the risk nomogram of constipation in patients with type 2 diabetes mellitus (T2DM) and to test its predictive ability.

Patients and Methods

This retrospective study included 746 patients with T2DM at two medical centers. Among the 746 patients with T2DM, 382 and 163 patients in the Beilun branch of the First Affiliated Hospital of Zhejiang University were enrolled in the training cohort and the validation cohort, respectively. A total of 201 patients in the First Affiliated Hospital of Nanchang University were enrolled in external validation cohorts. The nomogram was established by optimizing the predictive factors through univariate and multivariable logistic regression analysis. The prediction performance of the nomogram was measured by the area under the receiver operating characteristic curve (AUROC), the calibration curve, and the decision curve analysis (DCA). Furthermore, its applicability was internally and independently validated.

Results

Among the 16 clinicopathological features, five variables were selected to develop the prediction nomogram, including age, glycated hemoglobin (HbA1c), calcium, anxiety, and regular exercise. The nomogram revealed good discrimination with an area under the receiver operating characteristic curve (AUROC) of 0.908 (95% CI = 0.865-0.950) in the training cohort, and 0.867 (95% CI = 0.790-0.944) and 0.816 (95% CI = 0.751-0.881) in the internal and external validation cohorts, respectively. The calibration curve presented a good agreement between the prediction by the nomogram and the actual observation. The DCA revealed that the nomogram had a high clinical application value.

Conclusion

In this study, the nomogram for pretreatment risk management of constipation in patients with T2DM was developed which could help in making timely personalized clinical decisions for different risk populations.

Advanced glycation end products and bone - How do we measure them and how do they correlate with bone mineral density and fractures? A systematic review and evaluation of precision of measures

The role of advanced glycation end products (AGEs) in bone fragility especially in diabetic bone disease is increasingly recognized and researched. As skeletal frailty in diabetes does not correlate to bone mineral density (BMD) in the same way as in postmenopausal osteoporosis, BMD may not be a suitable measure of bone quality in persons with diabetes. Abundant research exists upon the effect of AGEs on bone, and though full understanding of the mechanisms of actions does not yet exist, there is little doubt of the clinical relevance. Thus, the measurement of AGEs as well as possible treatment effects on AGEs have become issues of interest. The aim of this report is to summarize results of measurements of AGEs. It consists of a systematic review of the existing literature on AGE measurements in clinical research, an evaluation of the precision of skin autofluorescence (SAF) measurement by AGE Reader® (Diagnoptics), and a short commentary on treatment of osteoporosis in patients with and without diabetes with respects to AGEs. We conclude that various AGE measures correlate well, both fluorescent and non-fluorescent and in different tissues, and that more than one target of measure may be used. However, pentosidine has shown good correlation with both bone measures and fracture risk in existing literature and results on SAF as a surrogate measurement is promising as some corresponding associations with fracture risk and bone measures are reported. As SAF measurements performed with the AGE Reader® display high precision and allow for a totally noninvasive procedure, conducting AGE measurements using this method has great potential and further research of its applicability is encouraged.

Osteoporosis and Alveolar Bone Health in Periodontitis Niche: A Predisposing Factors-Centered Review

Periodontitis is a periodontal inflammatory condition that results from disrupted periodontal host-microbe homeostasis, manifested by the destruction of tooth-supporting structures, especially inflammatory alveolar bone loss. Osteoporosis is characterized by systemic deterioration of bone mass and microarchitecture. The roles of many systemic factors have been identified in the pathogenesis of osteoporosis, including endocrine change, metabolic disorders, health-impaired behaviors and mental stress. The prevalence rate of osteoporotic fracture is in sustained elevation in the past decades. Recent studies suggest that individuals with concomitant osteoporosis are more vulnerable to periodontal impairment. Current reviews of worse periodontal status in the context of osteoporosis are limited, mainly centering on the impacts of menopausal and diabetic osteoporosis on periodontitis. Herein, this review article makes an effort to provide a comprehensive view of the relationship between osteoporosis and periodontitis, with a focus on clarifying how those risk factors in osteoporotic populations modify the alveolar bone homeostasis in the periodontitis niche.

Zoledronate promotes osteoblast differentiation in high-glucose conditions via the p38MAPK pathway

Zoledronate (ZOL) were found to inhibit bone resorption in an animal model of diabetes, high glucose concentrations have been shown to decreased the osteogenesis-related gene expression. But the molecular mechanism by which high glucose levels affect osteoblasts and the effects of ZOL on osteoblast differentiation in a high-glucose environment remain unclear. Therefore, we aimed to investigate the effect of ZOL on osteoblast differentiation in a high-glucose environment and determine the responsible mechanism. Cell proliferation was detected by MTT assay, and cell differentiation was evaluated by immunofluorescence staining for alkaline phosphatase expression, alizarin red staining, cytoskeletal arrangement, and actin fiber formation. Real-time PCR and western blot analyses were performed to detect the mRNA and protein expression of p38MAPK, phosphorylated (p)-p38MAPK, CREB, p-CREB, collagen (COL) I, osteoprotegerin (OPG), and RANKL. The results showed that cell proliferation activity did not differ among the groups. But high glucose inhibited osteoblast differentiation; actin fiber formation; and p38MAPK, p-p38MAPK, CREB, p-CREB, COL I, and OPG expression, while promoting RANKL expression. However, we found that treatment with ZOL reversed these effects of high glucose. And further addition of a p38MAPK inhibitor led to inhibition of osteoblast differentiation and actin fiber formation, and lower p38MAPK, p-p38MAPK, CREB, p-CREB, COL I, and OPG expression than in the high glucose +ZOL group with higher RANKL expression than in the high glucose +ZOL group. Collectively, this study demonstrates that high glucose inhibits the differentiation of osteoblasts, and ZOL could partly overcome these effects by regulating p38MAPK pathway activity.

Associations between presence of diabetes, mortality and fracture type in individuals with a hip fracture

AIMS

An overlooked aspect of diabetes is an increased risk of hip fractures, with associated mortality. We investigated whether fracture type and/or burden of comorbidities explains the increased risk of mortality in diabetes after hip fracture.

METHODS

For this cohort study, we used a de-identified data set of hip fracture patients registered in a quality-of-care registry (2017/2018) included in Maastricht University Medical Centre.

RESULTS

Among 594 hip fracture patients, 90 (15.2 %) had diabetes. Median (IQR) age was 82 (71-87) years and 63.8 % were women. Compared to patients without, patients with diabetes had higher median Charlson Comorbidity Index [1 (0-2) vs 0 (0-2), P < 0.001)] and were more likely to sustain intertrochanteric/subtrochanteric fractures [54.4 vs 38.7 %, P = 0.02]. Over a median follow-up of 2.7 (1.6-3.3) years, crude mortality rate was 30.8 % in patients without and 50.0 % in patients with diabetes. This association remained unaltered after adjustment for age, sex, BMI, fracture type or burden of co-morbidities.

CONCLUSION

Individuals with diabetes display a greatly increased absolute mortality risk after hip fracture. This association was not attenuated after adjustment for fracture type or non-diabetes associated co-morbidity. These findings have important implications for diabetes care in hip fracture patients, and underline the importance of fracture prevention.

Maresin1 Suppresses High-Glucose-Induced Ferroptosis in Osteoblasts via NRF2 Activation in Type 2 Diabetic Osteoporosis

Maresin1 (MaR1) is an endogenous pro-resolving lipid mediator produced from polyunsaturated fatty acids and is believed to have antioxidant and anti-inflammatory properties. The objective of this study was to estimate MaR1′s impact on type 2 diabetic osteoporosis (T2DOP) and its pharmacological mode of action. An in vitro high-glucose model of the osteoblast cell line MC3T3-E1 was constructed and stimulated with MaR1. Type 2 diabetic rats were used to establish in vivo models of calvarial defects and were treated in situ with MaR1. The results revealed that, aside from preventing mortality and promoting the osteogenic capacity of MC3T3-E1 cells, MaR1 increased nuclear factor erythroid-2 related factor 2 (NRF2) signaling as well as the activity of glutathione peroxidase 4 (GPX4) and cystine-glutamate antiporter (SLC7A11) and caused the restraint of ferroptosis under hyperglycemic stimulation. However, the therapeutic impact of MaR1 was significantly diminished due to NRF2-siRNA interference and the ferroptosis activator Erastin. Meanwhile, these results were validated through in vivo experiments. These findings imply that MaR1 activated the NRF2 pathway in vivo and in vitro to alleviate high-glucose-induced ferroptosis greatly. More crucially, MaR1 might effectively reduce the risk of T2DOP.

Anti-osteoporosis effects of Anemarrhenae Rhizoma / Phellodendri Chinensis Cortex herb pair and its major active components in diabetic rats and zebrafish

ETHNOPHARMACOLOGICAL RELEVANCE

Anemarrhenae Rhizoma/Phellodendri Chinensis Cortex (AR/PCC) herb pair has been widely used in traditional Chinese medicines for the treatment of diabetic osteoporosis. However, the anti-diabetic osteoporotic active components of AR/PCC remain unclear. This study aimed to explore the major active ingredients in AR/PCC for its protective effects against bone deterioration induced by diabetes.

MATERIALS AND METHODS

The aqueous extracts of AR/PCC with different proportions (AR:PCC = 1:3, 1:2, 1:1, 2:1 and 3:1, w/w) were prepared. Streptozotocin-induced diabetic rats were orally administrated with the AR/PCC extracts. The absorbed phytochemical compounds in serum of diabetic rats were identified by ultra-high performance liquid chromatography with quadrupole time-of-flight mass spectrometry method and their contents in the AR/PCC extracts were determined by high performance liquid chromatography-ultraviolet detector-evaporative light scattering detector method. The absorbed compounds in the extracts were considered as the major potential active components in AR/PCC, and their combination was defined as M-AR/PCC. A component-knockout approach was applied to evaluate the contribution of each compound in M-AR/PCC. The larvae and adults of diabetic zebrafish models were then used to evaluated the anti-diabetic osteoporotic performance of the M-AR/PCC. The real-time reverse transcription polymerase chain reaction technique was applied to study the regulation effects of M-AR/PCC on osteogenesis and osteoclastgensis in diabetic zebrafish models.

RESULTS

The phenotypes of diabetic osteoporosis rats induced by streptozotocin were reversed by the oral administration of AR/PCC extracts with different ratios, as evidenced by the increased bone mineral density, bone volume density, trabecular thickness, trabecular number, and decreased trabecular separation of femoral metaphysis. Seven phytochemical compounds were detected in the serum and their contents in AR/PCC varied dramatically with different proportions, including 1 xanthone glycoside and 6 alkaloids. By using diabetic zebrafish larvae model and compound-knockout strategy, each compound in M-AR/PCC were proved to play an indispensable role in the positive regulatory actions in the bone mass of diabetic zebrafish. Furthermore, the herb pair with a ratio of 1:1 and the related M-AR/PCC showed the best therapeutic effects on diabetic osteoporosis. They showed similar performances on the inhibition of the tartrate-resistant acid phosphatase activity and the promotion of the alkaline phosphatase activity in diabetic adult zebrafish model. The M-AR/PCC treatment could decrease the blood glucose, upregulate the mRNA expression levels of osteoblast-related genes (alp, runx2b and opg) and downregulate the expression of osteoclast-related genes (acp5α, rankl and sost) in streptozotocin-induced zebrafish.

CONCLUSION

AR/PCC herb pair and its major active components possess potent anti-diabetic osteoporotic effect on streptozotocin-induced in vivo models. The combination of the seven active compounds derived from AR/PCC herbal pair could be a potential agent for protection against osteoporosis associated with diabetes.

Bone regeneration in critical-sized mandibular symphysis defects using bioceramics with or without bone marrow mesenchymal stem cells in healthy, diabetic, osteoporotic, and diabetic-osteoporotic rats

OBJECTIVES

To compare new bone formation in mandibular critical-sized bone defects (CSBDs) in healthy, diabetic, osteoporotic, and diabetic-osteoporotic rats filled with bioceramics (BCs) with or without bone marrow mesenchymal stem cells (BMSCs).

METHODS

A total of 64 adult female Sprague-Dawley rats were randomized into four groups (n = 16 per group): Group 1 healthy, Group 2 diabetic, Group 3 osteoporotic, and Group 4 diabetic-osteoporotic rats. Streptozotocin was used to induce type 1 diabetes in Group 2 and 4, while bilateral ovariectomy was used to induce osteoporosis in Group 3 and 4. The central portion of the rat mandibular symphysis was used as a physiological CSBD. In each group, eight defects were filled with BC (hydroxypatatite 60% and β-tricalcium phosphate 40%) alone and eight with BMSCs cultured on BC. The animals were sacrificed at 4 and 8 weeks, and the mandibles were processed for micro-computed tomography to analyze radiological union and bone mineral density (BMD); histological analysis of the bone union; and immunohistochemical analysis, which included immunoreactivity of vascular endothelial growth factor (VEGF) and bone morphogenetic protein 2 (BMP-2).

RESULTS

In all groups (healthy, diabetics, osteoporotics, and diabetics-osteoporotics), the CSBDs filled with BC + BMSCs showed greater radiological bone union, BMD, histological bone union, and more VEGF and BMP-2 positivity, in comparison with CSBDs treated with BC alone (at 4 and 8 weeks).

CONCLUSIONS

Application of BMSCs cultured on BCs improves bone regeneration in CSBDs compared with application of BCs alone in healthy, diabetic, osteoporotic, and diabetic-osteoporotic rats.

Network pharmacology and molecular docking approach to elucidate the mechanisms of Liuwei Dihuang pill in diabetic osteoporosis

Background

Diabetic osteoporosis (DOP) is one of the chronic complications of diabetes mellitus, but without a standardized treatment plan till now. Liuwei Dihuang pill (LDP) has gradually exerted a remarkable effect on DOP in recent years; its specific mechanism is not clear yet.

Methods

We adopted network pharmacology approaches, including multi-database search, pharmacokinetic screening, network construction analysis, gene ontology enrichment analysis, Kyoto Encyclopedia of Genes and Genomes pathway analysis and molecular docking to elaborate the active components, signaling pathways and potential mechanisms of LDP in the treatment of DOP.

Results

Twenty-seven active ingredients and 55 related disease targets have been found through integrated network pharmacology. Functional enrichment analysis shows that five key active ingredients, including beta-sitosterol, stigmasterol, diosgenin, tetrahydroalstonine, and kadsurenone, may give full scope to insulin secretion estrogen-level raising and angiogenesis in biological process through the pivotal targets. In addition, the underlying effect of PI3K/AKT/FOXO and VEGF pathways is also suggested in the treatment.

Conclusion

Based on systematic network pharmacology methods, we predicted the basic pharmacological effects and potential mechanisms of LDP in the treatment of DOP, revealing that LDP may treat DOP through multiple targets and multiple signaling pathways, which provide evidence for the further study of pharmacological mechanism and broader clinical thinking.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13018-022-03194-2.

Resveratrol Attenuates High Glucose-Induced Osteoblast Dysfunction via AKT/GSK3β/FYN-Mediated NRF2 Activation

Osteoblast dysfunction, induced by high glucose (HG), negatively impacts bone homeostasis and contributes to the pathology of diabetic osteoporosis (DOP). One of the most widely recognized mechanisms for osteoblast dysfunction is oxidative stress. Resveratrol (RES) is a bioactive antioxidant compound to combat oxidative damage. However, its role in the protection of HG-induced osteoblast dysfunction has not been clarified. Therefore, our study aimed to explore potential regulatory mechanisms of RES for attenuating HG-induced osteoblast dysfunction. Our results showed that osteoblast dysfunction under HG condition was significantly ameliorated by RES via the activation of nuclear factor erythroid 2-related factor (NRF2) to suppress oxidative stress. Furthermore, using Nrf2-shRNA and wortmannin, we identified that activation of NRF2 via RES was regulated by the AKT/glycogen synthase kinase 3β (GSK3β)/FYN axis.

Sexual dimorphism in the relation between sex hormones and osteoporosis in patients with type 2 diabetes mellitus

INTRODUCTION

To investigate the association between sex hormones and osteoporosis in type 2 diabetic mellitus (T2DM) patients.

MATERIALS AND METHODS

We performed a retrospective study in patients with T2DM. The patients were assigned into three groups (normal bone mineral density, osteopenia, and osteoporosis) in both sexes. The clinical characteristics, bone metabolic markers, and sex hormones were compared. The relationship between the sex hormones and osteoporosis was analyzed by ordinary regression analysis. Statistical analysis was performed using SPSS 26.0.

RESULTS

A total of 795 T2DM patients (446 men ≥ 50 years old and 349 postmenopausal women) were identified and analyzed. The osteoporosis group had the lowest estradiol level in men (P = 0.013) and the highest follicle-stimulating hormone (FSH) level in women (P = 0.042). In the multivariate analysis, men with lower estradiol levels (< 87.96 pmol/L) had a nearly 1.6-fold increased risk for osteoporosis than those with the higher estradiol levels (> 122.82 pmol/L). In addition, women with lower FSH (< 41.17 IU/L) had nearly 0.6-fold for osteoporosis compared to those with higher FSH (> 60.83 IU/L) after adjusting for age, duration of T2DM, body mass index, pulse pressure, creatinine clearance, glycosylated hemoglobin, fasting C-peptide, and estradiol (in FSH) or FSH (in estradiol).

CONCLUSION

In T2DM, the estrogen level was negatively correlated with osteoporosis in men, and the FSH level was positively correlated with the osteoporosis in women.

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.

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.

Exendin-4 and eldecalcitol synergistically promote osteogenic differentiation of bone marrow mesenchymal stem cells through M2 macrophages polarization via PI3K/AKT pathway

Background

The incidence of diabetic osteoporosis is increasing. This article evaluates the effect of combination treatment with the hypoglycemic drug exendin-4 (Ex-4) and the vitamin D analog eldecalcitol (ED-71) on improving diabetic osteoporosis and explores the relevant mechanism of action.

Method

Micro-CT, HE staining, immunohistochemistry, qPCR and ELISA were used to evaluate the impact of Ex-4 and ED-71 on bone formation and macrophage polarization in a mouse model of diabetic osteoporosis in vivo. Immunofluorescence, flow cytometry and qPCR were used to characterize the polarization type of macrophages treated with Ex-4 and ED-71 in vitro. A co-culture system of BMSCs and macrophages was established. Subsequently, crystal violet staining, alkaline phosphatase staining and alizarin red staining were used to evaluate the migration and osteogenesis differentiation of BMSCs.

Results

Ex-4 combined with ED-71 significantly reduced blood glucose levels and enhanced bone formation in mice with diabetic osteoporosis. In addition, Ex-4 synergized with ED-71 to induce the polarization of macrophages into M2 through the PI3K/AKT pathway. Macrophages treated with the combination of Ex-4 and ED-71 can significantly induce the osteogenic differentiation of BMSCs.

Conclusion

Ex-4 synergized with ED-71 to reduce blood glucose levels significantly. And this combination therapy can synergistically induce osteogenic differentiation of BMSCs by promoting M2 macrophages polarization, thereby improving diabetic osteoporosis. Therefore, the combination of Ex-4 and ED-71 may be a new strategy for the treatment of diabetic osteoporosis.

Lycopene Improves Bone Quality and Regulates AGE/RAGE/NF-кB Signaling Pathway in High-Fat Diet-Induced Obese Mice

Objective. This study was aimed at examining the effects of lycopene on bone metabolism in high-fat diet (HFD)- induced obese mice and to identify the potential underlying mechanisms. Methods. Mice were fed a HFD for 12 weeks and then continue with or without lycopene intervention (15 mg/kg) for additional 10 weeks. The effects of lycopene on blood glucose and lipid metabolism, as well as serum levels of total antioxidant capacity (T-AOC), superoxide dismutase (SOD), and malondialdehyde (MDA) were determined by biochemical assays. Bone histomorphological features and osteoclast activity were assessed by hematoxylin/eosin and tartrate-resistant acid phosphatase staining. Bone microstructure at the proximal tibial metaphysis and diaphysis was determined by microcomputed tomography. Tibial biomechanical strength and material profiles were measured by a three-point bending assay and Fourier transform infrared spectroscopy. Protein expressions involved in the AGE/RAGE/NF-кB signaling pathway were determined by western blot and/or immunohistochemical staining. Results. Lycopene consumption reduced body weight gain and improved blood glucose and lipid metabolism in HFD-induced obese mice. In addition, lycopene treatment preserved bone biomechanical strength, material profiles, and microarchitecture in obese mice. Moreover, these alterations were associated with an increase in serum levels of T-AOC and SOD, and a decline in serum levels of MDA, as well as a reduction of AGEs, RAGE, cathepsin K, and p-NF-кBp65 and NF-кBp65 expressions in the femurs and tibias of obese mice. Conclusion. Lycopene may improve bone quality through its antioxidant properties, which may be linked with the regulation of the AGE/RAGE/NF-кB signaling pathway in obese mice. These results suggest that lycopene consumption may be beneficial for the management of obesity-induced osteoporosis.

The Impact of GLP1 Agonists on Bone Metabolism: A Systematic Review

Background and Objectives: The association between diabetes mellitus and increased risk of bone fractures has led to the investigation of the impact of antidiabetic drugs on bone metabolism. Glucagon-like peptide-1 receptor agonists (GLP1RAs) are a relatively novel and promising class of anti-hyperglycemic drugs. In addition to their blood glucose lowering action, GLP1RAs seem to have additional pleiotropic properties such as a beneficial skeletal effect; although the underlying mechanisms are not completely understood. The present systematic review summarizes current evidence about GLP1RAs and their effects on bone metabolism and fracture. Methods: An extensive literature search was conducted based on electronic databases namely, PubMed, Google Scholar and Cochrane Central Register of Controlled Trials (CENTRAL) through October 2019 to January 2020 for articles related to bone mineral density, diabetes mellitus and GLP1RAs. We included articles published in English. Finally, we included four randomized controlled trials, three meta-analyses, a case-control study and a population-based cohort analysis. Results: Based on the articles included, the animal studies indicated the salutary skeletal effects of GLP1RAs in opposition to what has been commonly observed in human studies, showing that these agents have no impact on bone mineral density (BMD) and the turnover markers. Moreover, it was demonstrated that GLP1 was not associated with fracture risk as compared to other anti-hyperglycemic drugs. Conclusions: Findings from this systematic review have demonstrated the neutral impact of GLP1RAs on BMD. Moreover, further double-blind randomized controlled trials are needed to draw more meaningful and significant conclusions on the efficacy of GLP1RAs on BMD.

Axon guidance molecules in immunometabolic diseases

The global prevalence of metabolic diseases, such as obesity, diabetes, and atherosclerosis, is rapidly increasing and has now reached epidemic proportions. Chronic tissue inflammation is a characteristic of these metabolic diseases, indicating that immune responses are closely involved in the pathogenesis of metabolic disorders. However, the regulatory mechanisms underlying immunometabolic crosstalk in these diseases are not completely understood. Recent studies have revealed the multifaceted functions of semaphorins, originally identified as axon guidance molecules, in regulating tissue inflammation and metabolic disorders, thereby highlighting the functional coupling between semaphorin signaling and immunometabolism. In this review, we explore how semaphorin signaling transcends beyond merely guiding axons to controlling immune responses and metabolic diseases.

Sedentary lifestyle and body composition in type 2 diabetes

BACKGROUND

Body composition alterations may participate in the pathophysiological processes of type 2 diabetes (T2D). A sedentary lifestyle may be responsible for alterations of body composition and adverse consequences, but on which body composition of patients with T2D and to what extent the sedentary lifestyle has an effect have been poorly investigated.

METHODS

We recruited 402 patients with T2D for this cross-sectional study. All patients received questionnaires to evaluate sedentary time and were further divided into three subgroups: low sedentary time (LST, < 4 h, n = 109), middle sedentary time (MST, 4-8 h, n = 129) and high sedentary time (HST, > 8 h, n = 164). Each patient underwent a dual energy X-ray absorptiometry (DXA) scan to detect body composition, which included body fat percentage (B-FAT), trunk fat percentage (T-FAT), appendicular skeletal muscle index (ASMI), lumbar spine bone mineral density (BMD) (LS-BMD), femoral neck BMD (FN-BMD), hip BMD (H-BMD) and total BMD (T-BMD). Other relevant clinical data were also collected.

RESULTS

With increasing sedentary time (from the LST to HST group), B-FAT and T-FAT were notably increased, while ASMI, LS-BMD, FN-BMD, H-BMD and T-BMD were decreased (p for trend < 0.01). After adjustment for other relevant clinical factors and with the LST group as the reference, the adjusted mean changes [B (95% CI)] in B-FAT, T-FAT, ASMI, LS-BMD, FN-BMD, H-BMD and T-BMD in the HST group were 2.011(1.014 to 3.008)%, 1.951(0.705 to 3.197)%, - 0.377(- 0.531 to - 0.223) kg/m2, - 0.083(- 0.124 to - 0.042) g/cm2, - 0.051(- 0.079 to - 0.024) g/cm2, - 0.059(- 0.087 to - 0.031) g/cm2 and - 0.060(- 0.088 to - 0.033) g/cm2, p < 0.01, respectively.

CONCLUSIONS

A sedentary lifestyle may independently account for increases in trunk and body fat percentage and decreases in appendicular skeletal muscle mass and BMD of the lumbar spine, femoral neck, hip and total body in patients with T2D.

The effects of metformin and alendronate in attenuating bone loss and improving glucose metabolism in diabetes mellitus mice

Background: To explore the anti-osteoporosis and anti-diabetes effects and potential underlying mechanisms of treatment with metformin and alendronate in diabetes mellitus mice.

Methods: Eight-week-old C57 BL/KS db/db and db/+ female mice were evaluated according to the following treatment group for 12 weeks: control group, diabetes mellitus group, diabetes mellitus with metformin group, diabetes mellitus with Alendronate group, diabetes mellitus with metformin plus alendronate group. Glucose level, glucose tolerance test, bone mineral density, bone microarchitecture, bone histomorphometry, serum biomarkers, and qPCR analysis.

Results: Combined metformin and alendronate can improve progression in glucose metabolism and bone metabolism, including blood glucose levels, blood glucose levels after 4 and 16 hours fasting, glucose tolerance test results, insulin sensitivity and reduces bone loss than the diabetes group. The use of alendronate alone can increase significantly serum glucagon-like peptide-1 levels than the diabetes group. The use of metformin alone can improve bone microstructure such as Tb.Sp and Tb.N of spine in diabetic mice.

Conclusion: The combined use of alendronate and metformin has an anti-diabetes and anti-osteoporotic effect compared with diabetic mice, but they appear to act no obvious synergistically between alendronate and metformin.