BACKGROUND:With the increasing demand for orthopedic implants,the search for materials with good biocompatibility and degradability has become a research hotspot.Magnesium-lithium-gadolinium(Mg-Li-Gd)alloy has good degradability,biocompatibility,and mechanical properties,providing ideal supporting conditions for fracture healing.OBJECTIVE:To evaluate the effects of Mg-Li-Gd alloy implants on bone healing in rats.METHODS:A circular half-defect model was made on the lateral side of the right mid-femoral segment in 28 SD rats,and the rats were randomly divided into two groups.The stainless steel group was fixed with a stainless steel intramedullary nail,and the magnesium alloy group was fixed with an Mg-Li-Gd alloy intramedullary nail,with 14 rats in each group.At 2,8,and 14 weeks after surgery,right femur X-ray and Micro-CT examinations,as well as hematoxylin-eosin staining,immunohistochemical staining,and western blot assay were performed.RESULTS AND CONCLUSION:(1)X-ray film:At 2 weeks after surgery,the osteotomy lines of both groups were clear,the density of the intramedullary nail in the magnesium alloy group was close to that of bone tissue,and the density of the intramedullary nail in the stainless steel group was higher than that of bone tissue.At 8 weeks after surgery,the osteotomy lines of both groups were blurred,and the intramedullary nail in the magnesium alloy group had corroded and degraded.At 14 weeks after surgery,the osteotomy lines of both groups disappeared,and the intramedullary nail in the magnesium alloy group further corroded and degraded.(2)Micro-CT:At 2 weeks after surgery,callus began to form in both groups;8 weeks after surgery,the stainless steel group entered the callus remodeling stage,and a relatively dense bone structure was formed at the bone defect site,and the magnesium alloy group showed obvious callus hyperplasia at the bone defect site.At 14 weeks after surgery,the stainless steel group showed a mature bone remodeling process,and thick cortical bone was formed at the bone defect site,and thinner cortical bone was formed in the magnesium alloy group.(3)Hematoxylin-eosin staining:At 2 weeks after surgery,a large number of osteoblasts,osteocytes,a small number of osteoclasts and trabecular structures were observed in the magnesium alloy group,while relatively few osteoblasts and osteocytes were observed in the stainless steel group.At 8 weeks after surgery,a large number of osteoblasts,osteocytes,and mature trabecular structures were observed in the magnesium alloy group,while a large number of osteocytes and lamellar bones were observed in the stainless steel group.At 14 weeks after surgery,lamellar bones were observed in the magnesium alloy group,while mature bone tissue was observed in the stainless steel group.(4)Immunohistochemical staining and western blot assay:At the same time point,the expression levels of bone morphogenetic protein 2,osteocalcin,and RUNX2 proteins in the magnesium alloy group were higher than those in the stainless steel group.(5)The results showed that compared with stainless steel materials,Mg-Li-Gd alloy had no obvious advantage in promoting the formation of fracture healing structure.

BACKGROUND:With the increasing demand for orthopedic implants,the search for materials with good biocompatibility and degradability has become a research hotspot.Magnesium-lithium-gadolinium(Mg-Li-Gd)alloy has good degradability,biocompatibility,and mechanical properties,providing ideal supporting conditions for fracture healing.OBJECTIVE:To evaluate the effects of Mg-Li-Gd alloy implants on bone healing in rats.METHODS:A circular half-defect model was made on the lateral side of the right mid-femoral segment in 28 SD rats,and the rats were randomly divided into two groups.The stainless steel group was fixed with a stainless steel intramedullary nail,and the magnesium alloy group was fixed with an Mg-Li-Gd alloy intramedullary nail,with 14 rats in each group.At 2,8,and 14 weeks after surgery,right femur X-ray and Micro-CT examinations,as well as hematoxylin-eosin staining,immunohistochemical staining,and western blot assay were performed.RESULTS AND CONCLUSION:(1)X-ray film:At 2 weeks after surgery,the osteotomy lines of both groups were clear,the density of the intramedullary nail in the magnesium alloy group was close to that of bone tissue,and the density of the intramedullary nail in the stainless steel group was higher than that of bone tissue.At 8 weeks after surgery,the osteotomy lines of both groups were blurred,and the intramedullary nail in the magnesium alloy group had corroded and degraded.At 14 weeks after surgery,the osteotomy lines of both groups disappeared,and the intramedullary nail in the magnesium alloy group further corroded and degraded.(2)Micro-CT:At 2 weeks after surgery,callus began to form in both groups;8 weeks after surgery,the stainless steel group entered the callus remodeling stage,and a relatively dense bone structure was formed at the bone defect site,and the magnesium alloy group showed obvious callus hyperplasia at the bone defect site.At 14 weeks after surgery,the stainless steel group showed a mature bone remodeling process,and thick cortical bone was formed at the bone defect site,and thinner cortical bone was formed in the magnesium alloy group.(3)Hematoxylin-eosin staining:At 2 weeks after surgery,a large number of osteoblasts,osteocytes,a small number of osteoclasts and trabecular structures were observed in the magnesium alloy group,while relatively few osteoblasts and osteocytes were observed in the stainless steel group.At 8 weeks after surgery,a large number of osteoblasts,osteocytes,and mature trabecular structures were observed in the magnesium alloy group,while a large number of osteocytes and lamellar bones were observed in the stainless steel group.At 14 weeks after surgery,lamellar bones were observed in the magnesium alloy group,while mature bone tissue was observed in the stainless steel group.(4)Immunohistochemical staining and western blot assay:At the same time point,the expression levels of bone morphogenetic protein 2,osteocalcin,and RUNX2 proteins in the magnesium alloy group were higher than those in the stainless steel group.(5)The results showed that compared with stainless steel materials,Mg-Li-Gd alloy had no obvious advantage in promoting the formation of fracture healing structure.

Objective:To construct and validate a risk prediction model for major complications 30 days after surgery in the elderly patients with hip fracture.Methods:A retrospective study was conducted to analyze the clinical data of 276 elderly patients with hip fracture who had been admitted to Department of Trauma and Orthopaedics, The Hospital Affiliated to Chengde Medical University from June 2019 to December 2021. There were 96 males and 180 females with an age of (74.5±9.3) years, and 139 femoral neck fractures and 137 intertrochanteric fractures. The outcome of this study was whether major complications occurred within 30 days after surgery. Multiple logistic regression analysis identified the risk factors for major complications in the elderly patients with hip fracture within 30 days after surgery. The forward step-by-step method and likelihood ratio test were used to screen the best prediction model. A nomogram was constructed to display the model. The stability and effectiveness of the model were evaluated by the receiver operating characteristic curve (ROC), Hosmer-Lemeshow goodness-of-fit test, clinical decision curve and clinical impact curve analysis.Results:Logistic regression analysis showed that decreased preoperative hemoglobin ( P< 0.05), time from admission to surgery >72 hours ( OR=3.001, 95% CI: 1.564 to 5.758, P<0.001), control of nutritional status (CONUT) score >4 points ( OR=3.394, 95% CI: 1.724 to 6.680, P<0.001), and age-adjusted modified frailty index (aamFI) >2 points ( OR=2.875, 95% CI: 1.548 to 5.339, P= 0.001), increased operation time ( OR=1.016, 95% CI: 1.006 to 1.025, P=0.001), and surgical bleeding >60 mL ( OR=2.373, 95% CI: 1.016 to 5.540, P=0.046) were independent risk factors for major complications within 30 days after surgery in the elderly patients with hip fracture. The area under the ROC curve in the logistic risk prediction model was 0.846 (95% CI: 0.799 to 0.889), and the results of Hosmer-Lemeshow goodness-of-fit test showed ( χ2=8.080, P=0.426). The clinical decision curve and clinical impact curve showed that the prediction model was accurate and effective. Conclusion:Based on the patients' preoperative hemoglobin, time from admission to surgery, control of nutritional status score, age-adjusted modified frailty index, operation time and surgical blood loss, this study has constructed successfully a risk prediction model for complications 30 days after surgery in the elderly patients with hip fracture which enables medical staff to predict the occurrence of major postoperative complications.

Objective: To investigate the effects of cathepsin S(Cat S) on proliferation, migration and invasion of osteosarcoma cells and its potential regulatory mechanism. Methods: Normal osteoblasts(hFOB) and osteosarcoma cells(SAOS2 and MG63) were selected as the subjects of this study.Cat S small interfering(si) RNA(si-Cat S) and negative control sequence(si-NC) were transfected into SAOS2 and MG63 cells to modulate the expression of Cat S in osteosarcoma cells.The experimental cells were randomly divided into four groups: hFOB group(hFOB cells),Control group(untransfected SAOS2 or MG63 cells),si-NC group(SAOS2 or MG63 cells transfected with si-NC) and si-Cat S group(SAOS2 or MG63 cells transfected with si-Cat S).The expression of Cat S in SAOS2 and MG63 cells was detected by RT-PCR and Western blot.Effect of Cat S knockdown on the proliferation of SAOS2 and MG63 cells was assessed by CCK-8 and clone formation assays.And effects of Cat S knockdown on the migration and invasion of SAOS2 and MG63 cells were determined by wound-healing and Transwell assays, respectively.Western blot assay was performed to measure the effects of SAOS2 knockdown on the expressions of apoptosis-related proteins(Bcl-2,Bax and Caspase-3) and Wnt/β-catenin pathway related proteins(LRP5,β-catenin, C-myc and Cyclin D1) in SAOS2 cells. Results: Compared with hFOB group, the expression of Cat S in SAOS2 group and MG63 group was upregulated(P<0.001).In addition, compared with si-NC group, the proliferation, migration and invasion of cells in si-Cat S group were reduced(P<0. 001). Results of Western blot showed that compared with si-NC group,the expression of Bcl-2 in si-Cat S group was downregulated,while the expression of Bax and Caspase-3 were upregulated(P<0. 001). Meanwhile,compared with si-NC group,the expression of LRP5,β-catenin,C-myc and Cyclin D1 in si-Cat S group was downregulated(P<0. 001). Conclusion Cat S siRNA knockdown can inhibit the proliferation,migration and invasion of osteosarcoma cells and induce apoptosis by regulating Wnt/β-catenin pathway,indicating that Cat S may be one of the potential targets for the treatment of osteosarcoma.

Objective To evaluate the relationship between serum magnesium and coronary artery calcification (CAC) and their associated factors.Methods 131 patients with chronic kidney disease on regular hemodialysis (HD) were recruited into this study from December 2014 to December 2015 in our center.Demographic and clinical data of selected patients were collected.Serum fibroblast growth factor 23 (FGF-23) level was quantified by enzyme linked immunosorbent assay(ELISA).Quantification of coronary artery calcification score (CACs) was determined by multi-slice spiral computed tomography (MSCT).The relationships between serum magnesium and FGF-23 level,CACs,demographic and clinical data were investigated.Results Patients were divided into low serum magnesium group,normal serum magnesium group and high serum magnesium group according to their serum magnesium levels.There were significant differences in the distribution of diabetes history,serum phosphorus,serum albumin,serum pre albumin,serum uric acid among these three groups(P ＜ 0.05).A significant positive correlation was confirmed between serum magnesium level and serum albumin,serum pre albumin,serun phosphorus and serum uric acid by Pearson correlation analysis and Spearman correlation analysis (r=0.389,0.234,0.200,0.234,P=0.000,0.007,0.022,0.007,respectively).According to the degree of CAC,all maintenance hemodialysis (MHD) patients were divided into non-calcification group,low calcification group,moderate calcification group and high calcification group,and there were significant differences in the distribution of the age,serum phosphorus,serum magnesium,FGF-23 levels among these groups (P ＜ 0.05).Spearman correlation analysis showed that CACs was positively correlated with age,FGF-23,serum phosphorus (r=0.309,0.277,0.180,P=0.000,0.001,0.040,respectively),while negatively correlated with serum magnesium level (r=-0.238,P=0.006) in patients with MHD.The independent risk factors of CACs were aging,high level of FGF-23 in MHD patients by using ordinal logistic regression.However,Hypermagnesemia was a protective factor.Conclusions The history of diabetes,low serum albumin,phosphorus metabolism disorder and CAC are associated with hypomagnesemia in MHD patients.In MHD patients,aging as well as high level of FGF-23 are the risk factors of CAC,and hypermagnesemia is a protective factor of CAC.

Objective To investigate the frailty in maintenance hemodialysis (MHD) patients and its influence factors. Methods A total of 127 adults undergoing hemodialysis from January 2015 and January 2016 in our center were recruited. Their clinical data and blood biochemical data were collected. Frailty was assessed using Fried's Frailty Phenotype. Quantification of coronary artery calcification (CACs) was determined by multi-slice spiral computed tomography (MSCT). According to the frailty scores, patients were divided into non-frailty, pro-frailty and frailty group. Their in clinical and biochemical index as well as CACs were compared. The correlations of frailty scores with above index were assessed by Spearman's correlation. Multiple logistic regression analysis was applied to evaluate the effect factors of frailty on MHD patients. Results Among 127 selected patients, 46(36.22%) patients without frailty, 45(35.43%) patients with pro-frailty, and 36(28.35%) patients with frailty. The age, diabetes, haemoglobin, albumin, pre-albumin, C-reactive protein, fibroblast growth factor 23 (FGF23), CACs and left ventricular end-diastolic dimension (LVEDD) of the 3 groups had statistical differences (all P<0.05). The degrees of calcification among 3 groups were also different statistically (F=31.769, P<0.001). In patients with MHD, frailty was positively correlated with age (r=0.545, P<0.001), diabetes (r=0.236, P=0.008), C-reactive protein (r=0.245, P=0.006), FGF23 (r=0.189, P=0.034) and CACs (r=0.396, P<0.001), while negatively correlated with haemoglobin (r=-0.257, P=0.004), albumin (r=-0.380, P<0.001), pre-albumin (r=-0.313, P<0.001). Age (OR=1.076), C-reactive protein (OR=1.176), albumin (OR=0.796) and artery calcification (OR=2.465) were independent influence factors for frailty in MHD patients (all P<0.05). Conclusions The prevalence of frailty is high among MHD patients. Frailty is associated with age, C-reactive protein, albumin and artery calcification in MHD patients.

Objective To explore the association of serum soluble Klotho (sKlotho) with nonfatal cardiovascular disease (CVD) and all-cause/CVD mortality in maintenance hemodialysis (MHD) patients.Methods A total of 132 MHD patients admitted during October 2011 were enrolled.Serum sKlotho was measured by ELISA.Demographic data,including age,gender and comorbid conditions,were obtained from their medical histories,and parameters including calcium,phosphorus and albumin were assessed.The occurrence time of nonfatal CVD and all-cause mortality were recorded during the 60 months follow-up.MHD patients were categorized into four groups according to the quartiles of sKlotho:group Ⅰ (sKlotho ＜ 361.34 ng/L),group Ⅱ (361.34 ng/L≤sKlotho＜ 398.81 ng/L),group Ⅲ (398.81 ng/L≤sKlotho＜445.99 ng/L) and group Ⅳ (sKlotho≥445.99 ng/L).Spearman correlation analysis and binary Logistic regression analysis were used to test the association between sKlotho and nonfatal CVD events.The impacts of sKlotho on all-cause mortality and CVD mortality were assessed by Kaplan-Meier method with log-rank test.Cox regression model was applied to evaluate the effect of sKlotho on MHD patients outcomes.Results All 132 MHD patients had sKlotho ranging from 304.02 ng/L to 550.62 ng/L.And 87 patients suffered from nonfatal CVD,with 192 episodes of nonfatal CVD during the follow-up period.The sKlotho had negative correlations with coronary artery disease (r=-0.286,P=0.001),congestive heart failure (r=--0.190,P=0.029),cerebrovascular accident (r=-0.240,P=0.006) and peripheral arterial occlusion (r=-0.243,P=0.005).The sKlotho were risk factors of coronary artery disease (OR=0.989,P=0.023) and peripheral artery occlusion (OR=0.988,P=0.046).35 patients died in the follow-up period,including 27 death from CVD.The all-cause mortality and CYD mortality rates were significantly different among four groups (P=0.036,P=0.047).Survival rates of all-cause death and CVD death varied among four groups (x2=8.076,P=0.044;X2=7.866,P=0.049).Patients in group Ⅳ had higher survival rates of allcause death and CVD death than those in group Ⅰ and group Ⅱ (all P ＜ 0.05).Multivariate Cox regression analyses revealed diabetes and age were independent risk factors for all-cause mortality and CVD mortality (all P ＜ 0.05),but sKlotho was not associated with the poor prognosis (HR=0.996,P=0.256;HR=0.996,P=0.287).Conclusions Patients with lower sKlotho have worse nonfatal CVD ratio,especially coronary artery disease and peripheral arterial occlusion.Reduced serum sKlotho is associated with all-cause and CVD mortality,but sKlotho is still not a predictive indicator of prognosis of MHD patients.

Objective To explore the association between serum FGF23 and Klotho protein,and bone mineral density in maintenance hemodialysis (MHD) patients.Methods A total of 125 MHD patients admitted in the Hospital between January 2015 and November 2015 was enrolled.Their bone mineral densities of femur neck and lumbar spine were studied by dual-energy X-ray absorptiometry.These patients were divided into three groups as normal,osteopenic and osteoporotic,according to World Health Organization criteria based on bone mineral density T scores.Levels of serum FGF23,Klotho protein and 1,25(OH)2VitD3 were measured by ELISA.The parameters including calcium,phosphorus,and parathyroid hormone were assessed.Results The incidences of osteopenia and osteoporosis at the femur neck and lumbar spine in MHD patients were 82.40％ and 56.00％ respectively.No significant difference was found in the levels of serum FGF23 among normal,osteopenic and osteoporotic groups on the basis of femur neck and lumbar spine bone mineral density (P ＞ 0.05).No correlation was found between FGF23 and bone mineral density.There however were significant differences in the levels of serum Klotho protein among three groups on the basis of femoral neck bone mineral density (P ＜ 0.05).And the levels of Klotho protein in the osteoporotic group [(387.172±54.137) ng/L] were significantly decreased than those in normal group [(429.883±41.776)ng/L] and osteopenic group [(410.598±61.056) ng/L] (P ＜ 0.05).There were also significant differences in the levels of serum Klotho protein among three groups in terms of lumbar spine bone mineral density (P ＜ 0.05),while the levels of Klotho protein in the osteopenic group [(387.263 ± 53.255) ng/L] were significantly decreased than those in normal group [(417.108±56.179) ng/L] (P＜ 0.05).A positive correlation was found between Klotho protein and bone mineral densities of femur neck and lumbar spine.Multiple linear regression analysis showed that one of the main factors influencing the degree of bone mineral density in MHD patients was Klotho protein.Conclusions CKD-MBD with low BMD is common and widespread in hemodialysis patients.FGF23 has no direct effect on bone mineral density in MHD patients;while Klotho protein is correlated with the severity of bone mineral density.High-level Klotho protein may reduce the severity of CKD-MBD with low BMD in MHD patients.

Objective To investigate the factors correlated to coronary artery calcification (CAC) in maintenance hemodialysis (MHD) patients.Methods This study included 132 patients(54 females,78 males),aged 26-94 years,who were on hemodialysis for 10-204 months(median dialysis duration 51.00 months).The parameters including calcium,phosphorus,parathyroid hormone,total cholesterol,low density lipoprotein,triglycerides,C-reactive protein (CRP),klotho,and so on were assessed.Quantification of CAC was determined by multi-slice spiral computed tomography (MSCT),known as the coronary artery calcification score (CACs).Results Ninety-two patients (69.70％) had CAC,with CACs ranging from 0 to 13 450.20.More than 30％ patients experienced one even a variety of cardiovascular and cerebrovascular diseases.A positive correlation was observed between the degree of CAC and the incidence of cardiovascular and cerebrovascular diseases.Whereas a positive correlation existed between CACs and age (r=0.347,P=0.000),duration of hemodialysis (r=0.245,P=0.005),systolic blood pressure (r=0.184,P=0.034),diabetes history (r=0.211,P=0.015),phosphorus (r=0.262,P=0.002),calcium-phosphorus product (r=0.247,P=0.004);and a negative correlation between CACs and klotho level (r=-0.294,P=0.001).Multivariate logistic regression analysis showed that the main factor influencing the degree of CAC in MHD patients was age.Conclusions CAC is common and widespread in hemodialysis patients,who are often accompanied by cardiovascular and cerebrovascular diseases.The prevalence rate of cardiovascular and cerebrovascular diseases increases with the aggravation of CAC degree.Age,duration of hemodialysis,systolic blood pressure,diabetes history,disturbance of calcium and phosphorus metabolism and klotho are correlated with the severity of CAC.Age is an independent risk factor of CAC degree.

Objective To examine the correlation of serum neutrophil gelatinase-associated lipocalin (NGAL) with dialysis adequacy,microinflammatory state and iron metabolism,and to assess the value of NGAL in identifying the dialysis adequacy in maintenance hemodialysis (MHD) patients.Methods A total of 150 MHD patients and 50 healthy control people were enrolled in the study.Clinical data were collected and serum NGAL,CRP,transferrin saturation,serum ferritin were measured.MHD patients were divided into adequacy group and non-adequacy group according to spKt/V value.Serum NGAL between two groups was compared and correlation of NGAL with spKt/V,inflammatory factors,and other clinical indexes was examined by Pearson,multivariate regression Logistic model and area under curve (AUC) of ROC.MHD patients were followed up for 3 months.Similar correlation analysis was carried out before and after follow up between two groups.Results Serum NGAL of MHD patients was higher compared to healthy people [(445.45±50.34) μg/L vs (50.02 ±6.45) μg/L].Among 150 MHD patients,95 were classified into adequacy group,while 55 into non-adequacy group according to spKt/V value.Serum NGAL was significantly higher in adequacy group as compared to non-adequacy group [(589.14±56.34) μg/L vs (360.13±46.23) μg/L,P＜0.05].Serum NGAL was positively correlated to spKt/V,CRP,TSAT [r=0.652,0.825,0.785,all P＜0.05],but not to serum ferritin.Serum NGAL was also correlated to spKt/V,CRP,TSAT by multivariate regression Logistic model.AUC showed that NGAL level could reflex the condition of dialysis adequacy.During the follow up,all adequacy patients remained the same adequacy status.Thirty-eight out of 55 non-adequacy patients were qualified for complete adequacy after intervention.The serum NGAL before and after intervention was (368.14±56.21) μg/L and (360.56±46.23) μg/L respectively without significant difference.Conclusions Serum NGAL is obviously higher in MHD patients with dialysis adequacy compared to those without dialysis adequacy.Serum NGAL is positively correlated to spKt/V,CRP,TSAT.NGAL can reflex the condition of dialysis adequate in MHD patients.