Atlantoaxial joint fusion using anterior transarticular screw fixation and bone grafting for atlantoaxial joint instability

Objective To evaluate the clinical application of atlantoaxial joint fusion using anterior transarticular screw fixation and bone grafting for atlantoaxial joint instability. Methods Twenty-three cases of atlantoaxial joint instability were

Periprosthetic joint infections in femoral neck fracture patients treated with hemiarthroplasty–should we use antibiotic-loaded bone cement?

BACKGROUND Hemiarthroplasty is the most common treatment in elderly patients with displaced intra-capsular femoral neck fracture(FNF).Prosthetic joint infection(PJI)is one of the most feared and frequent complications post-surgery because of the frail health status of these patients and the need for fast track surgery.Therefore,priorities should lie in effective preventive strategies to mitigate this burden.AIM To determine how much the implementation of the routine use of antibioticloaded bone cement(ALBC)as a relatively easy-to-apply amendment to the surgical practice reduces the infection rate in our hemiarthroplasty cohort.METHODS We retrospectively assessed all demographic,health status and treatment-related data of our FNF patients undergoing cemented hemiarthroplasty in the period from 2011 to 2017;241 patients were further analyzed after exclusion of patients with cancer-related sequelae and those who died before the end of the 1-year observation period.The PJI rate as diagnosed on basis of the Musculoskeletal Infection Society(MSIS)criteria 2011 was determined for each included patient and compared in function of the bone cement used for hip stem fixation.Patients were split into a group receiving a plain bone cement in the period from January 2011 to June 2013(non-ALBC group)and into a group receiving an ALBC in the period July 2013 to December 2017(ALBC group).Data analysis was performed with statistical software.We further calculated the cost-efficacy of the implementation of routine use of ALBC in the second group balancing the inhospital infection related treatment costs with the extra costs of use of ALBC.RESULTS In total 241 FNF patients who received cemented hemiarthroplasty in the period from January 2011 to January 2017 were eligible for inclusion in this retrospective study.There were 8 PJI cases identified in the ALBC group among n=94 patients,whereas 28 PJI cases were observed in the non-ALBC group among n=147 patients.The statistical analysis showed an infection risk reduction of 55.3%(in particular due to the avoidance of chronic delayed infections)in the ALBC group(95%CI:6.2%-78.7%;P=0.0025).The cost-evaluation analysis demonstrated a considerable cost saving of 3.500€per patient,related to the implementation of routine use of ALBC in this group.CONCLUSION Use of ALBC is a potent infection preventive factor in FNF patients receiving cemented hemiarthroplasties.It was further found to be highly cost-effective.

Value of dual-energy CT virtual noncalcium in the diagnosis of sacroiliac joint bone marrow edema

Objective:To explore the clinical value of dual energy CT(DECT)virtual noncalcium(VNCa)in the diagnosis of sacroiliac joint bone marrow edema(BME).Methods:A collection of 45 patients(21 males,24 females,and an average age of 34 years)who underwent MRI and DECT(Siemens Somatom definition force)examinations for the sacroiliac joints in our hospital from January 2019 to August 2020.After the DECT scan,the bone marrow pseudo-color map was obtained after VNCa processing.The bone marrow pseudo-color map was evaluated by two physicians.Take MRI test results as the gold standard,the application value of DECT VNCa technology in the diagnosis of sacroiliac joint BME was analyzed.Results:The positive predictive value(PPV),negative predictive value(NPV),sensitivity(Sen),specificity(Spe)and accuracy(Acc)of the qualitative diagnosis of iliac bone and sacral BME with DECT VNCa technology was:80.6%,85.2%,78.4%,86.8%,83.3%and 100%,64.9%,32.5%,100%,70.0%,respectively.The area of edema displayed by quantitative measurement of DECT VNCa image is smaller than the area measured by MRI image.The VNCa CT value(-71.66±72.97Hu)of the iliac edema area was higher than that of the non-edema area(-90.27±65.85Hu),and the VNCa CT value of the sacral edema area(-62.90±46.87Hu)was higher than that of the non-edema area(-101.08±134.02Hu),the best cut-off values(Cut-off values)for the quantitative diagnosis of iliac bone and sacral BME by VNCa are-66.40Hu and-50.60Hu,respectively.The curve of the receiver operating characteristic(ROC)of the iliac bone and sacrum area under the cure(AUC)is 0.720 and 0.706 respectively.There is a moderate negative correlation between the VNCa CT values of the ilium and sacrum in the edema area and the conventional CT values.Conclusion:The DECT VNCa technique has certain effectiveness in the diagnosis of sacroiliac joint BME,and its effectiveness in the diagnosis of ilium BME is better than sacrum.

Subsequent total joint arthroplasty: Are we learning from the first stage?

BACKGROUND With the increasing incidence of total joint arthroplasty(TJA),there is a desire to reduce peri-operative complications and resource utilization.As degenerative conditions progress in multiple joints,many patients undergo multiple proce-dures.AIM To determine if both physicians and patients learn from the patient’s initial arth-roplasty,resulting in improved outcomes following the second procedure.METHODS The institutional database was retrospectively queried for primary total hip arth-roplasty(THA)and total knee arthroplasty(TKA).Patients with only unilateral THA or TKA,and patients undergoing same-day bilateral TJA,were excluded.Patient demographics,comorbidities,and implant sizes were collected at the time of each procedure and patients were stratified by first vs second surgery.Outcome metrics evaluated included operative time,length of stay(LOS),disposition,90-d readmissions and emergency department(ED)visits.RESULTS A total of 642 patients,including 364 undergoing staged bilateral TKA and 278 undergoing bilateral THA,were analyzed.There was no significant difference in demographics or comorbidities between the first and second procedure,which were separated by a mean of 285 d.For THA and TKA,LOS was significantly less for the second surgery,with 66%of patients having a shorter hospitalization(P<0.001).THA patients had significantly decreased operative time only when the same sized implant was utilized(P=0.025).The vast majority(93.3%)of patients were discharged to the same type of location following their second surgery.However,when a change in disposition was present from the first surgery,patients were significantly more likely to be discharged to home after the second procedure(P=0.033).There was no difference between procedures for post-operative readmissions(P=0.438)or ED visits(P=0.915).CONCLUSION After gaining valuable experience recovering from the initial surgery,a patient’s perioperative outcomes are improved for their second TJA.This may be the result of increased confidence and decreased anxiety,and it supports the theory that enhanced patient education pre-operatively may improve outcomes.For the surgical team,the second procedure of a staged THA is more efficient,although this finding did not hold for TKA.

First Metatarsophalangeal Joint Arthrodesis: Comparison of Mesenchymal Stem Cell Allograft versus Autogenous Bone Graft Fusion Rates

With patients undergoing first time 1st metatarsophalangeal joint arthrodesis using graft material when it was required to fill cystic bone voids, we retrospectively compared the time to fusion (clinical and radiographic), and non-union rate between the patient’s own bone autograft (n = 62) versus a mesenchymal stem cell impregnated allograft group (n = 51). A third control group (n = 52) was included in which an end-to-end arthrodesis was performed and no graft interposition was used or necessary. The non-union rate was 4% (n = 2) in the control group, 5.9% (n = 4) in the autograft group, and 9.5% (n = 5) in the mesenchymal stem cell allograft group. The time for radiographic fusion was 6.46 weeks for the control group, 6.52 weeks for the autograft group, and 6.53 weeks for the mesenchymal stem cell allograft group. The difference in time to clinical and radiographic union and the non-union rate were not found to be statistically significant among all 3 groups. Patient comorbidities and their possible effects on union rates were also analyzed within the populations. Some comorbidities had statistically significantly non-unions within the population, notably smoking (p = 0.024) and Rheumatoid arthritis (p = 0.001), however the populations were fairly small. The use of allogeneic bone graft impregnated with mesenchymal stem cells yields a similar fusion rate as with the use of autologous bone graft harvested from the surrounding area. The allograft impregnated with mesenchymal stem cells is a viable alternative yielding similar results when local autogenous bone graft is not available, not obtainable, or conditions warrant its use.

Current concepts in the management of recurrent anterior gleno-humeral joint instability with bone loss

The management of recurrent anterior gleno-humeral joint instability is challenging in the presence of boneloss.It is often seen in young athletic patients and dislocations related to epileptic seizures and may involve glenoid bone deficiency,humeral bone deficiency or combined bipolar lesions.It is critical to accurately identify and assess the amount and position of bone loss in order to select the most appropriate treatment and reduce the risk of recurrent instability after surgery.The current literature suggests that coracoid and iliac crest bone block transfers are reliable for treating glenoid defects.The treatment of humeral defects is more controversial,however,although good early results have been reported after arthroscopic Remplissage for small defects.Larger humeral defects may require complex reconstruction or partial resurfacing.There is currently very limited evidence to support treatment strategies when dealing with bipolar lesions.The aim of this review is to summarise the current evidence regarding the best imaging modalities and treatment strategies in managing this complex problem relating particularly to contact athletes and dislocations related to epileptic seizures.

Molecularly specific detection of bacterial lipoteichoic acid for diagnosis of prosthetic joint infection of the bone

Discriminating sterile inflammation from infection, especially in cases of aseptic loosening versus an actual prosthetic joint infection, is challenging and has significant treatment implications. Our goal was to evaluate a novel human monoclonal antibody（mAb） probe directed against the Gram-positive bacterial surface molecule lipoteichoic acid（LTA）. Specificity and affinity were assessed in vitro. We then radiolabeled the anti-LTA mAb and evaluated its effectiveness as a diagnostic imaging tool for detecting infection via immuno PET imaging in an in vivo mouse model of prosthetic joint infection（PJI）. In vitro and ex vivo binding of the anti-LTA mAb to pathogenic bacteria was measured with Octet, ELISA, and flow cytometry. The in vivo PJI mouse model was assessed using traditional imaging modalities, including positron emission tomography（PET） with [^（18）F]FDG and [^（18）F]Na F as well as X-ray computed tomography（CT）, before being evaluated with the zirconium-89-labeled antibody specific for LTA（[^（89）Zr]SAC55）.The anti-LTA mAb exhibited specific binding in vitro to LTA-expressing bacteria. Results from imaging showed that our model could reliably simulate infection at the surgical site by bioluminescent imaging, conventional PET tracer imaging, and bone morphological changes by CT. One day following injection of both the radiolabeled anti-LTA and isotype control antibodies, the anti-LTA antibody demonstrated significantly greater（P 〈 0.05） uptake at S. aureus-infected prosthesis sites over either the same antibody at sterile prosthesis sites or of control non-specific antibody at infected prosthesis sites. Taken together, the radiolabeled anti-LTA mAb, [^（89）Zr]SAC55, may serve as a valuable diagnostic molecular imaging probe to help distinguish between sterile inflammation and infection in the setting of PJI. Future studies are needed to determine whether these findings will translate to human PJI.

A radiologic analysis of 136 cases of bone and joint lesions following burn

This paper reviewed 136 cases with definite bone and joint lesions selected froma total of 4286 burn patients.The clinical appearance,blood and urine biochemistry,blood cultures,gross and histological autopsy examination as well as surgical and biopsyspecimens were studied with emphasis on X-ray manifestations.The lesions were classi-fied,according to their X-ray appearances,into four types:alterations limited to thebone,alterations involving periarticular structures,changes of the joint and deformity ofthe bone and joint.The pathogenesis and radiological appearances of osteoporosis,mutila-tion of the fingers as well as incidence and pathogenesis of heterotopic para-articularossification were analysed and discussed.

A TETRACYCLINE LABELING STUDY OF SUBCHONDRAL BONE TISSUES IN OSTEOARTHRITIC HIP JOINT

Seven female patients (mean age of 56 years) with advanced hip joint osteoarthritis underwent total hip replacement. Four days before operation they were given oral tetracycline for two days. During operation specimens were taken from the white articular cartilage, the yellowish articular cartilage and the ivory bone together with their subchondral bone tissues. The undecalcified specimens were cut into 10 μm sections and observed under the fluorescence microscope. In all the specimens the following findings could be observed. 1. The osteoarthritic articular cartilage became thinner, with uneven surface and fissures. 2. The superficial and deep surfaces and the central part of the subchondral bone plate showed bright golden yellow fluorescence. It reflected extensive new bone formation. 3. The subchondral bone trabeculae also revealed bright golden yellow fluorescence on their peripheral borders, so trabeculae turned thicker obviously. 4. The marrow tissues between the bone trabeculae exhibited particulate or spherical bright golden yellow fluorescence, reflecting new bone formation in the marrow. The particulate and spherical bright golden yellow fluorescent materials might aggregate, enlarge and merge into large piece of new bone and they also fused with the neighbouring bone trabeculae. The aforementioned changes in the structure of the subchondral bone tissues increased greatly the mass in the osteoarthritic femoral head.

Profile of Knee’s Bone and Joint Tuberculosis in Adults: About 33 Cases

The authors report toward a monocentric retrospective and descriptive study on a 08 year period, 33 cases of knee osteoarticular tuberculosis (OAT) of adult, certified by bacteriologic and/or histolological evidence proof of the sample (synovial biopsy) after a knee arthrotomy. There were 07 cases of arthritis and 26 cases of osteoarthritis. The treatment of knee OAT was medical (anti-tubercular poly-chemotherapy) on one year duration. The surgery was useful in front of some clinical presentations. After a minimum of 18 months, a functional evaluation was done following the Lequesne algo-functionnal index. None had signs of local recurrence testifying the adequacy of medical treatment, even if it is long and binding. The main of our case series is to establish an epidemiological, clinical and biological profile of the knee tuberculosis of adult and to research elements of prognosis through an analysis of results.

Evaluation of Lo＂wenstein-Jensen Medium Culture,MGIT 960 Culture and Different Specimen Types inDiagnosis of Bone and Joint Tuberculosis

Objective： The aim of this study was to evaluate L-J （Lo＂wenstein-Jensen） medium culture, MGIT 960 culture anddifferent specimen types in diagnosis of BJTB （bone and joint tuberculosis）. Methods：： Specimens of pus, caseous necrosis,tuberculous granuloma and sequestrum were collected from 52 BJTB patients. All specimens were cultured using both MGIT 960system and L-J medium; and all pus were amplified using real-time PCR to detect the presence of M. tuberculosis DNA. KeyFindings： A total of 191 specimens were collected. Granuloma had better chance to produce positive outcomes by L-J mediumculture, while for sequestrum MGIT 960 culture had higher yield, but there was no significant difference in the recovery rates amongdifferent types of specimen either by L-J culture （Z2 = 0.638, P = 0.888） or by MGIT960 culture （Z2 = 1.399, P = 0.706）. MGIT960culture had significantly higher recovery rate than L-J culture, With a combined culture and PCR-based test, the recovery rate of pusspecimen was significantly higher than that of either method alone （P 〈 0.05）. Conclusion： MGIT 960 culture is superior to L-Jculture in BJTB diagnosis; pus, sequestrum, granuloma and caseous necrosis are usable specimen for mycobacterial culture;combination of culture and molecular techniques can provide a better diagnostic significance.

ALK5 transfection of bone marrow mesenchymal stem cells to repair osteoarthritis of knee joint

Previous studies have suggested that the transforming growth factor-β receptor ALK5 is crucial for articular chondrogenesis by bone marrow mesenchymal stem cells. Here, the wild-type ALK5 plasmids were mutated by overlapping extended PCR and transfected into bone marrow mesenchymal stem cells. The knee joint osteoarthritis mouse model was constructed by cutting oft＂ the anterior cruciate ligament and divided into three groups： saline group, bone marrow mesenchymal stem cells and ALK5-transfected bone marrow mesenchymal stem cells group. HE staining showed that the articular cartilage lesions were more serious of saline group compared with that of mesenchymal stem cell group, and this trend was more pronounced as time goes on. Immunohistochemical staining showed that although the expression level of type II collagen in all three groups down-regulated gradually upon time, its expression in ALK5-transfected bone marrow mesenchymal stem cells group was significantly enhanced compared with the other two groups. Micro-CT also suggested that ALK5 transfection of mouse bone marrow mesenchymal stem cells would promote repairing the knee cartilage lesions with arthritis of the mice. Although the osteoarthritis mechanism underlying a variety of factors work together, and the appropriate proportion of ALKS/ALK1 was also emphasized for the treatment of osteoarthritis. This work therefore demonstrated that ALK5 transfection of bone marrow mesenchymal stem cells could be a promising stem cell therapy for repair of cartilage lesions.

Effect of different hip replacement methods under minimally invasive anterolateral approach on bone metabolism and joint pain in patients with femoral neck fracture

Objective: To explore the effect of different hip replacement methods under minimally invasive anterolateral approach on bone metabolism and joint pain in patients with femoral neck fracture. Methods: A total of 110 patients with femoral neck fracture who were treated in Ruijin Hospital North, Shanghai Jiaotong University School of Medicine between July 2015 and January 2017 were collected and divided into control group and observation group by random number table, each with 55 cases. Control group accepted half hip replacement under minimally invasive anterolateral approach, and observation group accepted total hip replacement under minimally invasive anterolateral approach. The differences in contents of bone metabolism and joint pain-related indexes were compared between the two groups before and after surgery. Results: Before surgery, serum contents of bone formation indexes, bone resorption indexes, inflammatory indexes and pain mediators were not statistically significant between the two groups. 1 month after surgery, serum bone formation indexes PINP, BAP and BGP contents of observation group were higher than those of control group;serum bone resorption indexes β-CTX and TRACP-5b contents were lower than those of control group;serum inflammatory indexes IL-1 and TNF-α contents were lower than those of control group;serum pain mediators 5-HT and PGE2 contents were lower than those of control group. Conclusion: Total hip replacement under minimally invasive anterolateral approach is more effective to promote the formation of bone formation/bone resorption balance and reduce the joint pain.

Effect of sinew-regulating and bone-setting manipulating combined with exercise training in the treatment of joint injury of distal radio-ulnar

Objective: To observe the effect of the joint injury of the distal radio-ulnar joint. Methods: 60 patients with Distal Radioulnar Joint (DRUJ) injury were divided into observation group and control group according to random number method. 30 cases were included in each of the two groups.Before and after treatment in patients with Visual Analogue Scale (Visual Analogue Scale, VAS) score, forearm pronation and supination electromyographic activity, methods of electric integral value (integral electromyogram, iEMG) and Wrist in patients with self assessment Scale (Patient - Rated Wrist Evaluation, PRWE) score evaluation, comparison, and the clinical observation on diagnosis of disease and curative effect of traditional Chinese medicine standard (assessment process by blind method).Results: compared with the two groups before and after treatment, VAS score decreased, forearm pronation and postpronation activity increased, iEMG value increased, and PRWE scale score decreased (all P < 0.05), and the curative effect of the treatment group was better than that of the control group (P < 0.05). The total effective rate of the treatment group [93.3% (28/30)] was higher than that of the control group [50%(15/30), P < 0.05].Conclusion: the combined exercise training of muscle and bone setting technique can effectively alleviate the pain of patients with radial ulnar joint injury, improve the rotation of the forearm, increase the recruitment of the anterior rotatory muscle, and improve the wrist function of patients, and the effect is better than if combined with forearm support fixation.

Broken Rotor Bar Fault Detection of Induction Motors Using a Joint Algorithm of Trust Region and Modified Bare-bones Particle Swarm Optimization

A precise detection of the fault feature parameter of motor current is a new research hotspot in the broken rotor bar(BRB) fault diagnosis of induction motors. Discrete Fourier transform(DFT) is the most popular technique in this field, owing to low computation and easy realization. However, its accuracy is often limited by the data window length, spectral leakage, fence e ect, etc. Therefore, a new detection method based on a global optimization algorithm is proposed. First, a BRB fault current model and a residual error function are designed to transform the fault parameter detection problem into a nonlinear least-square problem. Because this optimization problem has a great number of local optima and needs to be resolved rapidly and accurately, a joint algorithm(called TR-MBPSO) based on a modified bare-bones particle swarm optimization(BPSO) and trust region(TR) is subsequently proposed. In the TR-MBPSO, a reinitialization strategy of inactive particle is introduced to the BPSO to enhance the swarm diversity and global search ability. Meanwhile, the TR is combined with the modified BPSO to improve convergence speed and accuracy. It also includes a global convergence analysis, whose result proves that the TR-MBPSO can converge to the global optimum with the probability of 1. Both simulations and experiments are conducted, and the results indicate that the proposed detection method not only has high accuracy of parameter estimation with short-time data window, e.g., the magnitude and frequency precision of the fault-related components reaches 10^(-4), but also overcomes the impacts of spectral leakage and non-integer-period sampling. The proposed research provides a new BRB detection method, which has enough precision to extract the parameters of the fault feature components.

AN EXPERIMENTAL STUDY ON TRANSPLANTATION OF FROZEN CANINE PHALANGEAL JOINT ALLOGRAFTS INCORPORATED WITH AUTOGENIC BONE MARROW

目的 探讨经过多重钻孔并复合自体骨髓的冷冻异体犬足趾关节移植的疗效。方法 24只健康成年杂交犬，制备双侧后肢第2足趾近侧趾间关节1．5cm缺损模型，共48侧，随机分成A、B、C3组（n=16）。分别采用新鲜自体趾间关节（A组）、经钻孔并复合自体新鲜骨髓的冷冻异体趾间关节（B组）及单纯冷冻异体趾间关节（C组）修复缺损。于术后1、3、6和12个月分别行X线摄片和组织病理学检查，了解移植骨关节的成活情况。结果 根据移植关节术后X线片和组织学改变，犬趾骨关节移植后的病变可分为轻度、中度和重度变性3级。A组移植骨关节3～12个月始终表现为轻度变性；B组移植骨关节1～6个月为轻度变性，骨孔中央软骨内成骨现象明显，12个月部分移植骨关节为中度变性；C组从1个月出现移植骨关节中度变性，3个月移植骨关节重度变性。结论 冷冻异体犬足趾关节内多重钻孔并复合自体新鲜骨髓．能有效延缓异体骨关节的早、中期变性，单纯冷冻异体骨关节移植后早期可能发生严重变性。

Icariin accelerates bone regeneration by inducing osteogenesisangiogenesis coupling in rats with type 1 diabetes mellitus

BACKGROUND Icariin(ICA),a natural flavonoid compound monomer,has multiple pharmacological activities.However,its effect on bone defect in the context of type 1 diabetes mellitus(T1DM)has not yet been examined.AIM To explore the role and potential mechanism of ICA on bone defect in the context of T1DM.METHODS The effects of ICA on osteogenesis and angiogenesis were evaluated by alkaline phosphatase staining,alizarin red S staining,quantitative real-time polymerase chain reaction,Western blot,and immunofluorescence.Angiogenesis-related assays were conducted to investigate the relationship between osteogenesis and angiogenesis.A bone defect model was established in T1DM rats.The model rats were then treated with ICA or placebo and micron-scale computed tomography,histomorphometry,histology,and sequential fluorescent labeling were used to evaluate the effect of ICA on bone formation in the defect area.RESULTS ICA promoted bone marrow mesenchymal stem cell(BMSC)proliferation and osteogenic differentiation.The ICA treated-BMSCs showed higher expression levels of osteogenesis-related markers(alkaline phosphatase and osteocalcin)and angiogenesis-related markers(vascular endothelial growth factor A and platelet endothelial cell adhesion molecule 1)compared to the untreated group.ICA was also found to induce osteogenesis-angiogenesis coupling of BMSCs.In the bone defect model T1DM rats,ICA facilitated bone formation and CD31hiEMCNhi type H-positive capillary formation.Lastly,ICA effectively accelerated the rate of bone formation in the defect area.CONCLUSION ICA was able to accelerate bone regeneration in a T1DM rat model by inducing osteogenesis-angiogenesis coupling of BMSCs.

Crosstalk between Wnt and bone morphogenetic protein signaling during osteogenic differentiati

Mesenchymal stem cells(MSCs)originate from many sources,including the bone marrow and adipose tissue,and differentiate into various cell types,such as osteoblasts and adipocytes.Recent studies on MSCs have revealed that many transcription factors and signaling pathways control osteogenic development.Osteogenesis is the process by which new bones are formed;it also aids in bone remodeling.Wnt/β-catenin and bone morphogenetic protein(BMP)signaling pathways are involved in many cellular processes and considered to be essential for life.Wnt/β-catenin and BMPs are important for bone formation in mammalian development and various regulatory activities in the body.Recent studies have indicated that these two signaling pathways contribute to osteogenic differen-tiation.Active Wnt signaling pathway promotes osteogenesis by activating the downstream targets of the BMP signaling pathway.Here,we briefly review the molecular processes underlying the crosstalk between these two pathways and explain their participation in osteogenic differentiation,emphasizing the canonical pathways.This review also discusses the crosstalk mechanisms of Wnt/BMP signaling with Notch-and extracellular-regulated kinases in osteogenic differentiation and bone development.

Hydrogel loaded with bone marrow stromal cell-derived exosomes promotes bone regeneration by inhibiting inflammatory responses and angiogenesis

BACKGROUND Bone healing is a complex process involving early inflammatory immune regu-lation,angiogenesis,osteogenic differentiation,and biomineralization.Fracture repair poses challenges for orthopedic surgeons,necessitating the search for efficient healing methods.AIM To investigate the underlying mechanism by which hydrogel-loaded exosomes derived from bone marrow mesenchymal stem cells(BMSCs)facilitate the process of fracture healing.METHODS Hydrogels and loaded BMSC-derived exosome(BMSC-exo)gels were charac-terized to validate their properties.In vitro evaluations were conducted to assess the impact of hydrogels on various stages of the healing process.Hydrogels could recruit macrophages and inhibit inflammatory responses,enhance of human umbilical vein endothelial cell angiogenesis,and promote the osteogenic differen-tiation of primary cranial osteoblasts.Furthermore,the effect of hydrogel on fracture healing was confirmed using a mouse fracture model.RESULTS The hydrogel effectively attenuated the inflammatory response during the initial repair stage and subsequently facilitated vascular migration,promoted the formation of large vessels,and enabled functional vascularization during bone repair.These effects were further validated in fracture models.CONCLUSION We successfully fabricated a hydrogel loaded with BMSC-exo that modulates macrophage polarization and angiogenesis to influence bone regeneration.

Low-intensity pulsed ultrasound reduces alveolar bone resorption during orthodontic treatment via Lamin A/C-Yes-associated protein axis in stem cells

BACKGROUND The bone remodeling during orthodontic treatment for malocclusion often requires a long duration of around two to three years,which also may lead to some complications such as alveolar bone resorption or tooth root resorption.Low-intensity pulsed ultrasound(LIPUS),a noninvasive physical therapy,has been shown to promote bone fracture healing.It is also reported that LIPUS could reduce the duration of orthodontic treatment;however,how LIPUS regulates the bone metabolism during the orthodontic treatment process is still unclear.AIM To investigate the effects of LIPUS on bone remodeling in an orthodontic tooth movement(OTM)model and explore the underlying mechanisms.METHODS A rat model of OTM was established,and alveolar bone remodeling and tooth movement rate were evaluated via micro-computed tomography and staining of tissue sections.In vitro,human bone marrow mesenchymal stem cells(hBMSCs)were isolated to detect their osteogenic differentiation potential under compression and LIPUS stimulation by quantitative reverse transcription-polymerase chain reaction,Western blot,alkaline phosphatase(ALP)staining,and Alizarin red staining.The expression of Yes-associated protein(YAP1),the actin cytoskeleton,and the Lamin A/C nucleoskeleton were detected with or without YAP1 small interfering RNA(siRNA)application via immunofluorescence.RESULTS The force treatment inhibited the osteogenic differentiation potential of hBMSCs;moreover,the expression of osteogenesis markers,such as type 1 collagen(COL1),runt-related transcription factor 2,ALP,and osteocalcin(OCN),decreased.LIPUS could rescue the osteogenic differentiation of hBMSCs with increased expression of osteogenic marker inhibited by force.Mechanically,the expression of LaminA/C,F-actin,and YAP1 was downregulated after force treatment,which could be rescued by LIPUS.Moreover,the osteogenic differentiation of hBMSCs increased by LIPUS could be attenuated by YAP siRNA treatment.Consistently,LIPUS increased alveolar bone density and decreased vertical bone absorption in vivo.The decreased expression of COL1,OCN,and YAP1 on the compression side of the alveolar bone was partially rescued by LIPUS.CONCLUSION LIPUS can accelerate tooth movement and reduce alveolar bone resorption by modulating the cytoskeleton-Lamin A/C-YAP axis,which may be a promising strategy to reduce the orthodontic treatment process.