BACKGROUND:Sarcopenia is an age-related systemic skeletal muscle disease,which is associated with a variety of adverse outcomes such as falls,functional decline,frailty,and death.Postmenopausal women are one of the high-risk groups for sarcopenia.OBJECTIVE:To develop a predictive model for assessing the risk of sarcopenia in Chinese postmenopausal women based on high-quality database.METHODS:Data for this study were derived from 2 370 postmenopausal women from the China Health and Retirement Longitudinal Study(CHARLS),and sarcopenia was assessed using the Asian Working Group on Sarcopenia 2019(AWGS2019)recommended metrics.The study cohort was randomized into a training set(70％)and a validation set(30％).Risk factors for sarcopenia in postmenopausal women were screened using the least absolute shrinkage and selection operator,ten-fold cross-validation,and logistic regression.Nomogram predicting the risk of sarcopenia in postmenopausal women was constructed based on the risk factors,and the model efficacy was evaluated by the receiver operating characteristic curve and area under the curve(AUC),calibration curve,and decision curve analysis.RESULTS AND CONCLUSION:The prevalence of sarcopenia in this study was 23.50％and age,place of residence,sleep quality,cognitive function,depression,and the number of chronic diseases were selected as predictors of sarcopenia in postmenopausal women.The nomogram model showed good discrimination between the training and validation sets,with an AUC value of 0.751(95％confidence interval=0.724-0.778,P＜0.001),a specificity of 72.2％,and a sensitivity of 63.2％in the training set,and an AUC value of 0.763(95％confidence interval=0.721-0.805,P＜0.001),with a specificity of 69.6％and a sensitivity of 70.8％.The calibration curve showed a relatively significant agreement between the nomogram model and the actual observations,and the decision curve analysis demonstrated broad and good clinical utility.To conclude,the nomogram to assess the risk of sarcopenia constructed based on age,place of residence,sleep quality,cognitive function,depression,and number of chronic diseases,provides an effective tool for identifying and eliminating risk factors for sarcopenia in Chinese postmenopausal women,and helps to reduce the incidence of sarcopenia.

BACKGROUND:Sarcopenia is an age-related systemic skeletal muscle disease,which is associated with a variety of adverse outcomes such as falls,functional decline,frailty,and death.Postmenopausal women are one of the high-risk groups for sarcopenia.OBJECTIVE:To develop a predictive model for assessing the risk of sarcopenia in Chinese postmenopausal women based on high-quality database.METHODS:Data for this study were derived from 2 370 postmenopausal women from the China Health and Retirement Longitudinal Study(CHARLS),and sarcopenia was assessed using the Asian Working Group on Sarcopenia 2019(AWGS2019)recommended metrics.The study cohort was randomized into a training set(70％)and a validation set(30％).Risk factors for sarcopenia in postmenopausal women were screened using the least absolute shrinkage and selection operator,ten-fold cross-validation,and logistic regression.Nomogram predicting the risk of sarcopenia in postmenopausal women was constructed based on the risk factors,and the model efficacy was evaluated by the receiver operating characteristic curve and area under the curve(AUC),calibration curve,and decision curve analysis.RESULTS AND CONCLUSION:The prevalence of sarcopenia in this study was 23.50％and age,place of residence,sleep quality,cognitive function,depression,and the number of chronic diseases were selected as predictors of sarcopenia in postmenopausal women.The nomogram model showed good discrimination between the training and validation sets,with an AUC value of 0.751(95％confidence interval=0.724-0.778,P＜0.001),a specificity of 72.2％,and a sensitivity of 63.2％in the training set,and an AUC value of 0.763(95％confidence interval=0.721-0.805,P＜0.001),with a specificity of 69.6％and a sensitivity of 70.8％.The calibration curve showed a relatively significant agreement between the nomogram model and the actual observations,and the decision curve analysis demonstrated broad and good clinical utility.To conclude,the nomogram to assess the risk of sarcopenia constructed based on age,place of residence,sleep quality,cognitive function,depression,and number of chronic diseases,provides an effective tool for identifying and eliminating risk factors for sarcopenia in Chinese postmenopausal women,and helps to reduce the incidence of sarcopenia.

Lower extremity arteriosclerosis obliterans(LEASO) is a disease in which systemic atherosclerosis affects the blood-supplying arteries of the lower extremities, resulting in chronic ischemia of the lower extremities. Angiopoietin-like protein 2(Angptl2) is a newly discovered pro-inflammatory protein that promotes the development of atherosclerosis by inducing vascular inflammatory responses. It is closely associated with certain risk factors for LEASO, such as advanced age, obesity, and type 2 diabetes. In addition, the high expression of Angptl2 in LEASO correlates with the continued progression of LEASO and may reflect the severity of the disease, suggesting that Angptl2 may be an important serologic biomarker for LEASO. In this article, we review the progress of research on the correlation between Angptl2 and LEASO, and analyze the value of Angptl2 as a biomarker for LEASO.

BACKGROUND:Previous studies by the research group have shown that core proteoglycan in Cornus Cervi Col la can enter the bone,promote the proliferation and osteogenic differentiation of bone marrow mesenchymal stem cells,and has a good repair effect on steroid-induced osteonecrosis of the femoral head.OBJECTIVE:To investigate the therapeutic effect and potential mechanism of Cornus Cervi Colla on steroid-induced osteonecrosis of the femoral head in rats by fecal non-targeted fecal metabolomics.METHODS:Thirty SD rats were randomly divided into three groups using a random number table method:the control group(n=10)was injected with normal saline into the right gluteal muscle(injected on the first 3 days of each week for 3 consecutive weeks),and was given pure water gavage(once a day for 6 consecutive weeks).The model group(n=10)was injected with methylprednisolone sodium succinate into the right gluteal muscle(injected on the first 3 days of each week for 3 consecutive weeks)to establish a steroid-induced osteonecrosis of the femoral head model,and was given pure water gavage(once a day for 6 consecutive weeks).The Cornus Cervi Co I la group(n=10)was also established with a steroid-induced osteonecrosis of the femoral head model,and was given Cornus Cervi Col la gavage(once a day for 6 consecutive weeks).After gavage,cecal feces and femoral heads were collected for fecal metabolomics analysis and bone tissue Micro-CT and hematoxylin-eosin staining,respectively.RESULTS AND CONCLUSION:(1)Metabolomics analysis results showed that there were 233 differential metabolites between the Cornus Cervi Col la and model groups,with 65 significantly differing and clearly annotated metabolites.Lipid and amino acid metabolites were significantly increased,with bile acids,sulfated steroids,ephedrine,hypoxanthine,betaine,L-carnitine,B-mouse bile acid,cytidine,4-pyridoxic acid,taurine,N-acetyl-d-glucosamine,and butyric acid being the most impacted(variable weight value VIP＞5).The metabolic pathways of taurine and hypotaurine were crucial in the metabolic regulatory network(pathway impact=0.428 57).(2)Micro-CT scanning results of bone tissue showed that the femoral heads of rats in the model group and the Cornus Cervi Col la group had different degrees of damage;the femoral head contour was irregular;the trabeculae in the subchondral bone of the femoral head were missing and disordered,and some cystic structures were visible.Compared with the model group,the degree of trabecular damage in the rats of the Cornus Cervi Colla group was milder.Hematoxylin-eosin staining results showed that the trabeculae in the subchondral bone of the femoral heads of rats in the model group and the Cornus Cervi Colla group were sparse or interrupted,and the empty bone lacuna rate and adipocyte invasion were increased.Compared with the model group,the empty bone lacuna rate and adipocyte invasion in the subchondral bone of the femoral heads of rats in the Cornus Cervi Colla group were reduced.(3)These results conclude that Cornus Cervi Colla potentially mitigates steroid-induced osteonecrosis of the femoral head through the metabolic processes involving taurine and associated pathways.

BACKGROUND:With the continuous exploration of the pathogenesis of osteonecrosis,more and more research evidence shows that neuroimaging change is closely related to the onset of osteonecrosis.However,the specific causal relationship between neuroimaging change and osteonecrosis is still unclear.OBJECTIVE:To evaluate the causal relationship between neuroimaging indices and osteonecrosis using Mendelian Randomization analysis.METHODS:Neuroimaging data were obtained from the UK Biobank database in the UK,which included a total of 36 778 individuals.Osteonecrosis data were obtained from the FinnGen database in Finland,including 1 543 cases and 391 037 controls.Instrumental variables were extracted and screened from outcome factors,and two-sample Mendelian randomization analysis was performed.The data were analyzed by inverse variance weighted method,MR-Egger,weighted median method,simple model method,and weighted model method.The inverse variance weighted method was used as the main analysis method,and the other four methods were used as supplements.To verify the feasibility and stability of the data,sensitivity analysis of the results was performed.Based on the complexity of causal inference,a reverse Mendelian randomization analysis was further performed to evaluate the potential reverse causal relationship.RESULTS AND CONCLUSION:(1)The results of inverse variance weighted analysis showed that 97 neuroimaging data were positively correlated with osteonecrosis(P＜0.05,OR＞1);2 data were heterogeneous and 6 data had horizontal pleiotropy.95 neuroimaging phenotypes were negatively correlated with osteonecrosis(P＜0.05,OR＜1);5 data were heterogeneous,and 9 data had horizontal pleiotropy;2 groups of data had reverse causal relationships.(2)The two-sample Mendelian randomization analysis established the causal relationship between neuroimaging indicators and osteonecrosis in the academic community.These large sample numbers from the UK and Finland provide a new theoretical basis for the pathophysiology of osteonecrosis,and also provide ideas and methods for the prediction,screening,early diagnosis and prognosis of osteonecrosis in China,which is conducive to improving the accuracy of clinical diagnosis and the effectiveness of treatment of osteonecrosis.

BACKGROUND:Osteonecrosis is an orthopedic disease that severely limits joint function,with complex pathogenesis involving multiple risk factors.Cathepsins,as a class of enzymes that play a key role in bone metabolism,are closely related to the proliferation,differentiation of bone cells,and remodeling of the bone matrix.However,previous studies have mostly focused on descriptive analyses,lacking direct evidence of causal relationships.OBJECTIVE:To clarify the potential causal relationship between cathepsins and osteonecrosis and to explore their possible mechanisms by analyzing large-scale sample data from the FinnGen database.METHODS:We obtained osteonecrosis-related data from the FinnGen database,including R9(a total of 359 399 samples:1 385 cases and 358 014 controls)and R10 versions(a total of 392 580 samples:1 543 cases and 391 037 controls).Single nucleotide polymorphisms associated with nine cathepsins(cathepsin B,E,F,G,H,O,S,L2,and Z)were acquired from a previous study(3 301 individuals).Univariate Mendelian randomization,reverse univariate Mendelian randomization,and multivariate Mendelian randomization analyses were conducted using the inverse variance weighted method,MR-Egger method,weighted median method,simple mode method,and weighted mode method.Initially,Mendelian randomization analysis was performed using osteonecrosis data from R9.Additionally,sensitivity analyses were conducted using Cochran's Q test,MR-Egger intercept,MR-PRESSO global test,and leave-one-out analysis to check for horizontal pleiotropy and heterogeneity.Subsequently,a validation analysis study was carried out on the R10 dataset,and a meta-analysis was conducted to combine the two datasets to explore the joint effect.RESULTS AND CONCLUSION:Univariate Mendelian randomization analysis results showed that higher levels of cathepsin B were significantly associated with a reduced risk of osteonecrosis(inverse variance weighted:odds ratio(OR)=0.865,95％confidence interval(CI):0.762-0.982,P=0.025),and no reverse causal relationship was found between the nine cathepsins and osteonecrosis(P＞0.05).These associations were validated by meta-analysis.Multivariate analysis,using the nine cathepsins as covariates,revealed a reverse causal relationship between the levels of cathepsin Band the risk of osteonecrosis(inverse variance weighted:OR=0.8710,95％CI:0.761-0.997,P=0.045),consistent with the results before adjustment.Sensitivity analyses based on heterogeneity and horizontal pleiotropy suggested that the results were relatively robust.This study suggests that there is a causal relationship between high levels of cathepsin B and the reduced risk of osteonecrosis,and it may serve as a biomarker for osteonecrosis,providing new directions and insights for the diagnosis and treatment of osteonecrosis.Although this study is based on data analysis of European populations,these findings have important implications for Chinese biomedical research,especially in understanding disease mechanisms,developing biomarkers,and formulating treatment strategies.They also encourage similar studies conducted on Chinese populations to explore the impact of racial and genetic background differences on the occurrence of osteonecrosis.

BACKGROUND:With the continuous exploration of the pathogenesis of osteonecrosis,more and more research evidence shows that neuroimaging change is closely related to the onset of osteonecrosis.However,the specific causal relationship between neuroimaging change and osteonecrosis is still unclear.OBJECTIVE:To evaluate the causal relationship between neuroimaging indices and osteonecrosis using Mendelian Randomization analysis.METHODS:Neuroimaging data were obtained from the UK Biobank database in the UK,which included a total of 36 778 individuals.Osteonecrosis data were obtained from the FinnGen database in Finland,including 1 543 cases and 391 037 controls.Instrumental variables were extracted and screened from outcome factors,and two-sample Mendelian randomization analysis was performed.The data were analyzed by inverse variance weighted method,MR-Egger,weighted median method,simple model method,and weighted model method.The inverse variance weighted method was used as the main analysis method,and the other four methods were used as supplements.To verify the feasibility and stability of the data,sensitivity analysis of the results was performed.Based on the complexity of causal inference,a reverse Mendelian randomization analysis was further performed to evaluate the potential reverse causal relationship.RESULTS AND CONCLUSION:(1)The results of inverse variance weighted analysis showed that 97 neuroimaging data were positively correlated with osteonecrosis(P＜0.05,OR＞1);2 data were heterogeneous and 6 data had horizontal pleiotropy.95 neuroimaging phenotypes were negatively correlated with osteonecrosis(P＜0.05,OR＜1);5 data were heterogeneous,and 9 data had horizontal pleiotropy;2 groups of data had reverse causal relationships.(2)The two-sample Mendelian randomization analysis established the causal relationship between neuroimaging indicators and osteonecrosis in the academic community.These large sample numbers from the UK and Finland provide a new theoretical basis for the pathophysiology of osteonecrosis,and also provide ideas and methods for the prediction,screening,early diagnosis and prognosis of osteonecrosis in China,which is conducive to improving the accuracy of clinical diagnosis and the effectiveness of treatment of osteonecrosis.

BACKGROUND:Previous studies by the research group have shown that core proteoglycan in Cornus Cervi Col la can enter the bone,promote the proliferation and osteogenic differentiation of bone marrow mesenchymal stem cells,and has a good repair effect on steroid-induced osteonecrosis of the femoral head.OBJECTIVE:To investigate the therapeutic effect and potential mechanism of Cornus Cervi Colla on steroid-induced osteonecrosis of the femoral head in rats by fecal non-targeted fecal metabolomics.METHODS:Thirty SD rats were randomly divided into three groups using a random number table method:the control group(n=10)was injected with normal saline into the right gluteal muscle(injected on the first 3 days of each week for 3 consecutive weeks),and was given pure water gavage(once a day for 6 consecutive weeks).The model group(n=10)was injected with methylprednisolone sodium succinate into the right gluteal muscle(injected on the first 3 days of each week for 3 consecutive weeks)to establish a steroid-induced osteonecrosis of the femoral head model,and was given pure water gavage(once a day for 6 consecutive weeks).The Cornus Cervi Co I la group(n=10)was also established with a steroid-induced osteonecrosis of the femoral head model,and was given Cornus Cervi Col la gavage(once a day for 6 consecutive weeks).After gavage,cecal feces and femoral heads were collected for fecal metabolomics analysis and bone tissue Micro-CT and hematoxylin-eosin staining,respectively.RESULTS AND CONCLUSION:(1)Metabolomics analysis results showed that there were 233 differential metabolites between the Cornus Cervi Col la and model groups,with 65 significantly differing and clearly annotated metabolites.Lipid and amino acid metabolites were significantly increased,with bile acids,sulfated steroids,ephedrine,hypoxanthine,betaine,L-carnitine,B-mouse bile acid,cytidine,4-pyridoxic acid,taurine,N-acetyl-d-glucosamine,and butyric acid being the most impacted(variable weight value VIP＞5).The metabolic pathways of taurine and hypotaurine were crucial in the metabolic regulatory network(pathway impact=0.428 57).(2)Micro-CT scanning results of bone tissue showed that the femoral heads of rats in the model group and the Cornus Cervi Col la group had different degrees of damage;the femoral head contour was irregular;the trabeculae in the subchondral bone of the femoral head were missing and disordered,and some cystic structures were visible.Compared with the model group,the degree of trabecular damage in the rats of the Cornus Cervi Colla group was milder.Hematoxylin-eosin staining results showed that the trabeculae in the subchondral bone of the femoral heads of rats in the model group and the Cornus Cervi Colla group were sparse or interrupted,and the empty bone lacuna rate and adipocyte invasion were increased.Compared with the model group,the empty bone lacuna rate and adipocyte invasion in the subchondral bone of the femoral heads of rats in the Cornus Cervi Colla group were reduced.(3)These results conclude that Cornus Cervi Colla potentially mitigates steroid-induced osteonecrosis of the femoral head through the metabolic processes involving taurine and associated pathways.

BACKGROUND:Osteonecrosis is an orthopedic disease that severely limits joint function,with complex pathogenesis involving multiple risk factors.Cathepsins,as a class of enzymes that play a key role in bone metabolism,are closely related to the proliferation,differentiation of bone cells,and remodeling of the bone matrix.However,previous studies have mostly focused on descriptive analyses,lacking direct evidence of causal relationships.OBJECTIVE:To clarify the potential causal relationship between cathepsins and osteonecrosis and to explore their possible mechanisms by analyzing large-scale sample data from the FinnGen database.METHODS:We obtained osteonecrosis-related data from the FinnGen database,including R9(a total of 359 399 samples:1 385 cases and 358 014 controls)and R10 versions(a total of 392 580 samples:1 543 cases and 391 037 controls).Single nucleotide polymorphisms associated with nine cathepsins(cathepsin B,E,F,G,H,O,S,L2,and Z)were acquired from a previous study(3 301 individuals).Univariate Mendelian randomization,reverse univariate Mendelian randomization,and multivariate Mendelian randomization analyses were conducted using the inverse variance weighted method,MR-Egger method,weighted median method,simple mode method,and weighted mode method.Initially,Mendelian randomization analysis was performed using osteonecrosis data from R9.Additionally,sensitivity analyses were conducted using Cochran's Q test,MR-Egger intercept,MR-PRESSO global test,and leave-one-out analysis to check for horizontal pleiotropy and heterogeneity.Subsequently,a validation analysis study was carried out on the R10 dataset,and a meta-analysis was conducted to combine the two datasets to explore the joint effect.RESULTS AND CONCLUSION:Univariate Mendelian randomization analysis results showed that higher levels of cathepsin B were significantly associated with a reduced risk of osteonecrosis(inverse variance weighted:odds ratio(OR)=0.865,95％confidence interval(CI):0.762-0.982,P=0.025),and no reverse causal relationship was found between the nine cathepsins and osteonecrosis(P＞0.05).These associations were validated by meta-analysis.Multivariate analysis,using the nine cathepsins as covariates,revealed a reverse causal relationship between the levels of cathepsin Band the risk of osteonecrosis(inverse variance weighted:OR=0.8710,95％CI:0.761-0.997,P=0.045),consistent with the results before adjustment.Sensitivity analyses based on heterogeneity and horizontal pleiotropy suggested that the results were relatively robust.This study suggests that there is a causal relationship between high levels of cathepsin B and the reduced risk of osteonecrosis,and it may serve as a biomarker for osteonecrosis,providing new directions and insights for the diagnosis and treatment of osteonecrosis.Although this study is based on data analysis of European populations,these findings have important implications for Chinese biomedical research,especially in understanding disease mechanisms,developing biomarkers,and formulating treatment strategies.They also encourage similar studies conducted on Chinese populations to explore the impact of racial and genetic background differences on the occurrence of osteonecrosis.

BACKGROUND:Osteonecrosis due to drugs is a serious adverse reaction occurring after the application of such drugs.Increasing evidence suggests that the gut microbiota composition is associated with osteonecrosis due to drugs.However,the causal relationship of the gut microbiota to osteonecrosis due to drugs is still unclear. OBJECTIVE:To evaluate the potential causal relationship between the gut microbiota and the risk of osteonecrosis due to drugs using the Mendelian randomization method. METHODS:A two-sample Mendelian randomization study was performed using the summary statistics of gut microbiota from the largest available genome-wide association study meta-analysis(n=13 266)conducted by the MiBioGen consortium as well as the summary statistics of osteonecrosis due to drugs obtained from the FinnGen consortium R9 release data(264 cases and 377 013 controls).Inverse variance weighted,MR-Egger,weighted median,weighted model and simple model were used to examine the causal association between gut microbiota and osteonecrosis due to drugs.Sensitivity analysis was used to test whether the results of the Mendelian randomization analysis were reliable.Reverse Mendelian randomization analysis was performed on all the bacteria as an outcome for effect analysis and sensitivity analysis. RESULTS AND CONCLUSION:Inverse variance weighted estimates suggested that Lentisphaerae(phylum),Lentisphaeria(class),Melainabacteria(class),Gastranaerophilales(order),Rhodospirillales(order),Victivallales(order)and Bifidobacterium(genus)had protective causal effects on osteonecrosis due to drugs.Methanobacteria(class),Bacillales(order),Methanobacteriaceae(family),Lachnospiraceae(family),Methanobacteriales(order),Holdemania(genus),Holdemania(UCG010 group)(genus),Odoribacter(genus)and Tyzzerella3(genus)had negative causal effects on osteonecrosis due to drugs.According to the results of reverse Mendelian randomization analysis,Clostridiaceae1(family),Peptostreptococcaceae(family),Streptococcaceae(family),Clostridiumsensustricto1(genus)and Streptococcus(genus)showed negative causal effects on osteonecrosis due to drugs.However,Eisenbergiella(genus)showed protective causal effects on osteonecrosis due to drugs.None of the bidirectional sensitivity analysis revealed heterogeneity or horizontal pleiotropy.When gut microbiota were used as exposure and osteonecrosis due to drugs as the outcome,Mendelian randomization analysis found that seven bacterial traits were positively correlated to osteonecrosis due to drugs,nine bacterial traits were negatively related to osteonecrosis due to drugs.When osteonecrosis due to drugs were used as exposure and gut microbiota as the outcome,reverse Mendelian randomization analysis found a negative correlated relationship with five bacterial traits and a positive causal relationship with one bacterial trait.By changing the diversity and composition of gut microbiota,it is expected to improve the incidence and prognosis of osteonecrosis due to drugs,providing new ideas for the study of orthopedic diseases.