Clinical significance of Periostin expression in the replacement of primary permanent teeth / 中国现代医生

Objective To investigate the effect of periostin on bone remodeling and autophagy during the period of tooth replacement and to investigate the mechanism of action of periostin in regulating the balance of bone metabolism during the replacement of primary and permanent teeth.Methods Fifteen cases each of experimental and control groups were collected from the periapical periodontal disease and multiple teeth extracted for periapical adhesions in the author's hospital,the mRNA levels of periostin,bone metabolism genes,and autophagy genes were detected in the specimens by in situ hybridization.Osteoblasts were cultured in vitro,periostin was added to the culture medium of the experimental group,and the expression of bone metabolism proteins[receptor activator of nuclear factor-κb ligand(RANKL),osteoprotegerin(OPG)]and autophagy proteins(LC3,Beclin-1)in osteoblasts was detected by Western blot.Results In situ hybridization results showed that periostin expression in the experimental group was lower than that in the control group(P<0.05),RANKL,LC3,BECN1 expression and RANKL/OPG values were higher than those in the control group(all P<0.05),and no significant differences were seen in OPG expression(P>0.05);protein blotting showed that RANKL,RANKL/OPG,LC3Ⅱ,Beclin-1,LC3Ⅱ/LC3Ⅰ were lower in the experimental group than in the control group(all P<0.05),and no significant differences were seen in OPG and LC3Ⅰ than in the control group(P>0.05).Conclusion Periostin reduces inflammation-induced bone resorption by reducing RANKL expression and improving hyperautophagic state.

Bone remodeling in the Masquelet-induced membrane model of rat femur by modulation of H-type vessels by total flavonoids of rhizome drynariae / 中国组织工程研究

BACKGROUND:Several studies have found that the total flavonoids of rhizome drynariae can promote neovascularization in the induced membrane,improve the biological properties of the induced membrane,and accelerate bone remodeling in the induced membrane,but the related molecular mechanisms still need to be further explored. OBJECTIVE:To explore the effect of total flavonoids of rhizome drynariae on bone remodeling in rat femoral Masquelet-induced membrane model by regulating H-type blood vessels. METHODS:Thirty-six male Sprague-Dawley rats were stratified by body mass and then randomly divided into blank group,model group and traditional Chinese medicine group,with 12 rats in each group.A 4-mm femoral bone defect model was established in all the rats.Bone defects in the model group and traditional Chinese medicine group were filled with polymethylmethacrylate bone cement.At 6 weeks after modeling,the tail bone of the rats was implanted in the blank group,as well as in the other two groups after removal of bone cement.The traditional Chinese medicine group was given 157.5 mg/kg per day of total flavonoids of rhizome drynariae at 3 days after bone implantation,while the model and blank groups were given the same amount of saline by gavage until the 8th week after bone implantation.Bone graft samples were taken for relevant testing at 8 weeks after implantation. RESULTS AND CONCLUSION:X-ray films showed that in the blank group,the fracture line in the defect area was clear,and only a small amount of bone callus formed;in the model group,the bone defect area still existed,where discontinuous cortical bone was visible;in the traditional Chinese medicine group,the defect area was filled with newborn bone tissues,the bone marrow cavity and part of the cortical bone formed,and the fracture line disappeared.Micro-CT scans showed that the amount of new bone in the defect area was low in the blank group,the number of bone trabeculae in the defect area was significantly increased in the model group,and a large amount of new bone tissue was filled in the bone defect area in the traditional Chinese medicine group.Hematoxylin-eosin staining results showed that in the blank group,only a small amount of new bone formed in the defect area and the quality of osteogenesis was poor;in the model group,there was more new bone tissue in the defect area,but some fibrous connective tissues were interspersed within the bone tissue;and in the traditional Chinese medicine group,a large amount of new bone formed in the defect area and the quality of osteogenesis was the best.CD31/Emcn immunofluorescence double-labeling staining results showed that the number of H-type blood vessels in the newborn bone tissue in the bone defect area of the blank group was sparse and sparsely distributed;compared with the blank group,there were more H-type blood vessels in the bone tissue in the bone defect area of the model group,and the blood vessels were distributed in relatively regular strips;the number of H-type blood vessels in the bone defect area of the traditional Chinese medicine group was the highest and the blood vessels were densely distributed.To conclude,the total flavonoids of rhizoma drynariae can upregulate the expression of H-type blood vessels to enhance the angiogenic-osteogenic effect,improve the osteogenic efficiency of the rat femoral Masquelet induced membrane model,and promote bone remodeling.

Role of autophagy in orthodontic tooth movement / 中国组织工程研究

BACKGROUND:The application of orthodontic force triggers autophagy in the periodontal tissue via diverse signaling pathways,augmenting or attenuating the activity of relevant cell types such as periodontal ligament cells,osteocytes,osteoclasts,and osteoblasts,thus facilitating the process of periodontal remodeling. OBJECTIVE:To review the research progress in orthodontic force mediated autophagy in periodontal tissue and its impact on orthodontic tooth movement. METHODS:The PubMed,Web of Science,China Biology Medicine disc and CNKI were searched for literature published from 2010 to 2023 to summarize the progress in orthodontics-related autophagy.And 76 papers were finally included in the analysis and discussion. RESULTS AND CONCLUSION:Orthodontic force can trigger a series of biochemical signal changes through periodontal mechanical receptors and aseptic inflammation they cause,leading to autophagy in periodontal tissue.Subsequently,autophagy generates corresponding feedback through cascaded amplified signaling pathways such as Phosphoinositide 3-kinase/protein kinase B,Hippo,and mitogen-activated protein kinase pathways,promoting periodontal tissue remodeling and ultimately achieving tooth movement and stability.Orthodontic force-induced autophagy can differentially regulate bone resorption on the tooth pressure side and bone formation on the tension side.Related targets have good prospects in the clinical application of orthodontic treatment.Orthodontics and autophagy have complex mechanisms.However,existing research has only focused on exploring the role of autophagy in orthodontic tooth movement.Further exploration is needed to investigate the mutual regulatory effects between autophagy and orthodontic tooth movement,as well as the interactions between upstream mechanical receptors and signaling pathways involved in related pathways.

Regulatory role of transforming growth factor beta subfamily in osteoarthritis / 中国组织工程研究

BACKGROUND:Osteoarthritis is one of the most common senile chronic degenerative diseases in China.Due to its complex pathogenesis and cellular molecular communication pathways,there is currently no effective method to slow down the progression of osteoarthritis.Studies have found that transforming growth factor-β is one of the key factors in the maintenance and regulation of joint stability and plays a significant role in the formation of early joints,as well as the development of bone and cartilage,and the remodeling of joints at various stages. OBJECTIVE:To review the regulatory role of the transforming growth factor-β subfamily in the occurrence and development of osteoarthritis,both domestically and internationally in recent years,to analyze the impacts it has at different stages of osteoarthritis,and to explore the potential application prospects of transforming growth factor-β in the clinical treatment of osteoarthritis,with a view to informing clinical treatment protocols.. METHODS:The relevant articles were searched by computer from CNKI Database and PubMed Database.The search terms were"osteoarthritis,transforming growth factor,signaling pathway,bone remodeling,cartilage degeneration,angiogenesis,treatment"in Chinese and English,respectively.Finally,57 articles were included for review. RESULTS AND CONCLUSION:The pathogenesis of osteoarthritis remains a subject of ongoing exploration with no unified consensus.Numerous studies highlight the close correlation between osteoarthritis and cytokines,focusing on the transforming growth factor-β superfamily as a pivotal mechanism and therapeutic breakthrough.Transforming growth factor-β plays a crucial role in early joint cartilage formation and maintenance,promoting cartilage repair.However,post-joint formation,its protective effect weakens,leading to potential destructive consequences.This dual regulatory role is a current clinical treatment focus,necessitating further research to delineate its application scope for standardized protocols.Highly active transforming growth factor-β participates in the regulation of bone cells,osteoblasts,and osteoclasts under mechanical stress,and intervenes in the subsequent remodeling of bone microstructure.Specific inhibitors present potential targeted therapeutics,yet their safety and efficacy in clinical settings require refinement.Vascular proliferation may serve as a potential disruptive pathway in transforming growth factor-β-mediated cartilage degeneration and subchondral bone remodeling.Abnormal communication pathways can further disrupt the homeostasis of the microenvironment of osteochondral units,thereby accelerating key pathological progressions of osteoarthritis.Research on transforming growth factor-β in osteoarthritic contexts is comprehensive,holding broad clinical application prospects.Drugs related to transforming growth factor-β are in clinical trial phases,but addressing potential impacts on other tissues and precise control of targeted delivery are critical concerns.As research advances,there is optimism for innovative breakthroughs in slowing the progression of osteoarthritis in the future.

Construction of double-layer bone-on-a-chip containing bone matrix / 中华创伤杂志

Objective:To construct a double-layer bone-on-a-chip containing bone matrix, with which the process of osteoblast and osteoclast differentiation in vitro is stimulated, aiming to provide a new platform for the development of osteoporosis medications. Methods:Software WorkSoild was used to design the double-layer and double-channel bone-on-a-chip and the template was fabricated by photolithography. With polydimethylsiloxane (PDMS) as the raw material, the main body of the chip was prepared by mold fabrication. The inlets and outlets of the four channels of the culture room were separated with bovine cortex bones and sealed with liquid storage columns. In the chip verification experiment, chips were divided into osteogenic and osteoclastic induction groups and osteogenic and osteoclastic control groups. In the osteogenic and osteoclastic induction groups, precursor cells of mouse embryonic osteoblast, MC3T3-E1 and mouse macrophage RAW264.7 were inoculated on the chip separately. Osteogenic induction lasted 14 days and osteoclastic induction 7 days. MC3T3-E1 cells and RAW264.7 cells were not induced in the osteogenic and osteoclastic control groups. The following indicators were observed: (1) Appearance and sealing performance of the chip: After the chip was prepared, photos were taken to observe its appearance and sealing tests were conducted to observe its sealing performance. (2) Biocompatibility: At 3 days after MC3T3-E1 cells were inoculated onto the chip and cultured and at 1, 3 and 5 days after RAW264.7 cells were inoculated onto the chip and cultured, the cell survival was observed with calcein acetoxymethyl ester/propidium iodide (AM/PI) staining and Cell Counting Kit 8 (CCK-8). (3) Osteogenic differentiation: Alkaline phosphatase (ALP) staining and alizarin red staining were performed on the cells in the osteogenic induction group to observe the osteogenic induction. RNA was collected from the osteogenic induction group and the osteogenic control group, the expression of osteoblast marker Runt-related transcription factor 2 (RUNX2), osteocalcin (OCN) and type I collagen (COL1A1) was detected by real-time florescent quantitative PCR (qPCR), and the differentiation degree and osteogenic ability of osteoblasts were observed. (4) Osteoclast differentiation: tartrate-resistant acid phosphatase (TRAP) staining was performed on cells in the osteoclastic induction group to observe osteoclast differentiation. RNA was extracted from the osteoclastic induction group and the osteoclastic control group for qPCR of osteoclast differentiation-related genes, and the expression levels of the osteoclast marker gene TRAP, cathepsin K (CTSK) and dendritic cell specific transmembrane protein (DC-STAMP) were detected.Results:The double-layer bone-on-a-chip containing bone matrix was 3 cm×3 cm in size and transparent as a whole. The structure of the system on the chip system was compact and had no seepage. It was shown by calcein AM/PI staining that at 3 days after MC3T3-E1 cells and RAW264.7 cells were cultured, very few red fluorescent dead cells were found. CCK-8 test showed that within 5 days after being cultured, the cell viability was all above 90%, indicating that the biocompatibility of the chip was good and the cells could survive and proliferate normally. The results of ALP and alizarin red staining showed that MC3T3-E1 cells successfully differentiated into osteoblasts and produced calcified nodules in the osteogenic induction group at 14 days after the induction. The qPCR results showed that the relative expression level of RUNX2 in MC3T3-E1 cells in the osteogenic induction group was 4.98±0.74, which was significantly higher than that of the control group (0.99±0.03) ( P<0.01). The relative expression level of OCN in MC3T3-E1 cells was 7.98±0.76, which was significantly higher than that of the control group (1.00±0.06) ( P<0.01). The relative expression level of COL1A1 in MC3T3-E1 cells was 7.07±0.56, which was significantly higher than that of the control group (0.97±0.03) ( P<0.01). The TRAP staining results showed that the RAW264.7 cells in the osteoclastic induction group differentiated to giant multinucleated osteoclasts, and TRAP protein was expressed in large quantity in the osteoclasts. The results of qPCR showed that the relative expression level of TRAP in RAW264.7 cells in the osteoclastic induction group was 3.35±0.37, which was significantly higher than that of the control group (1.01±0.06) ( P<0.01). The relative expression level of CTSK in RAW264.7 cells was 3.46±0.79, which was significantly higher than that of the control group (1.01±0.05) ( P<0.01). The relative expression level of DC-STAMP in RAW264.7 cells was 1.92±0.12, which was significantly higher than that of the control group (0.98±0.08) ( P<0.01). Conclusions:The double-layer bone-on-a-chip containing bone matrix is compact in structure, can be cultured in vitro for a long time, has good biocompatibility and can be used for inducing osteogenic and osteoclast differentiation. Therefore, it is expected to provide a new research platform for exploring the mechanism of osteoporosis and medication screening.

Finite element analysis of revision prostheses for tibial bone defects with different lengths of tibial stems / 中华骨科杂志

Objective:To evaluate the mechanical performance of customized metal prosthesis with tibia stems of varying lengths for tibial bone defects reconstruction.Methods:Morphologically matched postoperative finite element models of bone defect revision were developed, with three gradients (15 mm, 30 mm, and 45 mm) according to the degree of bone defect and were reconstructed with 3D printed tantalum metal prosthesis using three tibial stem lengths (80 mm, 120 mm, and 150 mm), respectively. Conventional static and dynamic (walking gait) loading was performed to analyze the peak tibial stress distribution and accumulated sliding distance at the prosthetic interface, and to assess the effects of the three tibial stems of different lengths on the stability of the customized tibial defect restorations and the internal tibial stress state.Results:The peak accumulated sliding distance of the dynamically loaded morphologically matched restorations ranged from 17.94 to 21.31 mm with static loading, which were 68% to 84.3% higher than those of 10.26 to 11.69 mm with static loading. The peak tibial stresses in the dynamically loaded model were greater than those in the statically loaded model, with an increase of 28%-49.2%, including 132.94-143.88 MPa in the statically loaded model and 170.41-200.14 MPa in the dynamically loaded model. The overall accumulated sliding distance of the tibia prosthetic model gradually decreased from the tibial osteotomy surface, and the accumulated peak sliding distances ranged from 10.26 to 11.69 mm for static loading, and from 17.94 to 21.31 mm for dynamic loading. The bone tissue stresses in the anterolateral and medial-posterior tibia increased gradually from top to bottom, and the maximum stress value in each section was in the posterior medial tibia (the maximum value was 200.14 MPa). The highest bone tissue stress in the lateral tibia was affected by the tibial stem length, which resulted in a different location, and it was the area most affected by stress shielding (maximum value of 170.65 MPa).Conclusion:For stability assessment of morphologically matched tantalum customized prosthesis, physiological gait dynamic loading studies are more reliable than static loading; the choice of tibial stem length depends on a combination of accumulated peak sliding distances and tibial bone stress distribution factors.

Isopsoralen accelerates tibia fracture healing by promoting bone formation in mice / 陆军军医大学学报

Objective To determine the effect of isopsoralen(ISO)on the healing of tibia fracture in mice and explore its underlying mechanism.Methods Fifty male C57BL/6 mice(2 month old,20±2 g)were randomly divided into model group and ISO treatment group,with 25 animals in each group.From the 3rd day after modeling,the mice from the ISO group were given an intragastric gavage of 40 mg/kg ISO,once per day for 28 consecutive days,while those of the model group was given same volume of normal saline in same way.On the 7th,14th,21st,and 28th day after gavage,the tibia on the surgical side was taken,and the fracture area was quantified by bone volume/total volume(BV/TV)after micro-CT scanning.The healing and shaping of the fracture end were observed through HE staining.ELISA was used to detect the serum contents of bone alkaline phosphatase(BALP)and procollagen type I N-terminal peptide(PINP)on the 14th day of gavage.Western blotting was employed to determine the expression levels of Collagen Ⅰ,Runx2,BMP2,OSX,and VEGF in the tibial callus tissue in 7 and 14 d after gavage.Vascular perfusion was applied to observe the callus microvessels in 28 d to quantitatively analyze the vascular volume fraction and vessel diameter.Immunohistochemical staining was conducted to observe the expression of VEGF in the callus in 14 d after gavage.Results HE staining displayed that the ISO group had faster healing process than the model group.Micro-CT quantification results showed that the ISO group had higher BV/TV ratio in 7 d after gavage though no statistical difference,significantly higher ratio in 14 d(P＜0.05),but obviously lower ratio in 21 and 28 d after gavage(both P＜0.05)when compared with the model group.The serum contents of BALP and PINP were also remarkably higher in the ISO group than the model group(P＜0.05).Western blotting results indicated that the expression levels of Collagen Ⅰ,Runx2,BMP2,OSX and VEGF in the ISO group were higher than those in the model group(P＜0.05).The results of angiography revealed that the vascular volume fraction and vessel diameter were notably increased in the ISO group than the model group(both P＜0.05).Immunohistochemical assay showed that the expression of VEGF was higher in the ISO group than the model group(P＜0.05).Conclusion ISO can improve the activity of osteoblasts,increase the expression of osteogenesis-related proteins,and accelerate the angiogenesis to promote fracture healing.

Analysis of peri-implant bone tissue between hydrophilic and rough implant surfaces in spontaneously hypertensive rats treated with losartan

Abstract Hypertensive individuals present alterations in their calcium metabolism that consequently decrease the concentration of this mineral in the bone tissue. Objectives to evaluate the morphological and functional characteristics of the peri-implant bone tissue that was formed during the healing process by the placement implants using two different surface treatments: hydrophilic Acqua™ (ACQ) and rough NeoPoros™ (NEO), in spontaneously hypertensive (SHR) and normotensive rats (Wistar) whether or not treated with losartan. Methodology In total, 96 male rats (48 Wistar and 48 SHR) were divided into eight subgroups: absolute control rough (COA NEO), absolute control hydrophilic (COA ACQ), losartan control rough (COL NEO), losartan control hydrophilic (COL ACQ), SHR absolute rough (SHR NEO), SHR absolute hydrophilic (SHR ACQ), SHR losartan rough (SHRL NEO), and SHR losartan hydrophilic (SHRL ACQ). The rats medicated with losartan received daily doses of the medication. NeoPoros™ and Acqua™ implants were installed in the tibiae of the rats. After 14 and 42 days of the surgery, the fluorochromes calcein and alizarin were injected in the rats. The animals were euthanized 67 days after treatment. The collected samples were analyzed by immunohistochemistry, biomechanics, microcomputerized tomography, and laser confocal scanning microscopy analysis. Results The osteocalcin (OC) and vascular endothelium growth factor (VEGF) proteins had moderate expression in the SHRL ACQ subgroup. The same subgroup also had the highest implant removal torque. Regarding microarchitectural characteristics, a greater number of trabeculae was noted in the control animals that were treated with losartan. In the bone mineralization activity, it was observed that the Acqua™ surface triggered higher values of MAR (mineral apposition rate) in the COA, COL, and SHRL groups (p<0.05). Conclusion the two implant surface types showed similar responses regarding the characteristics of the peri-implant bone tissue, even though the ACQ surface seems to improve the early stages of osseointegration.

Determinación de rangos de BCTx y N-MID Osteocalcina y asociación con Osteoporosis en mujeres chilenas posmenopáusicas

Introducción: La densitometría ósea (DO) tiene alta especificidad para el diagnóstico de osteoporosis, pero sensibilidad bajo lo óptimo para estimar el riesgo de fracturas. Éste, se puede calcular por algoritmos de predictores, y se ha propuesto incluir los marcadores óseos (MO), pero la magnitud de su asociación es incierta. El MO recomendado para medir resorción ósea es Beta-Cross Laps (B-CTx), y uno de formación ósea es la osteocalcina. Objetivos: 1) Establecer rangos de B-CTx y N-MID osteocalcina (N-MID) en mujeres posmenopáusicas (MPM), y comparar los niveles entre grupos: 1) Control sano y 2) Con DO alterada. Material y Métodos: Se reclutaron MPM, con DO del último año. Se realizó encuesta de factores de riesgo de fracturas y medición de MO. Se excluyeron MPM con causa secundaria para compromiso del recambio óseo. Resultados: 117 MPM (57 control, 60 DO alterada), 18 % osteoporosis, comparables. Los rangos de B-CTx y N-MID fueron 0,41 ± 0,18 [IC95% 0,37- 0,45] y 22,76 ± 7,73 [IC95% 21,29-24,24] ng/mL. Los niveles promedios de B-CTx y N-MID fueron más altos en grupo con DO alterada (0,46 ± 0,19 y 24,29 ± 8,04 ng/mL). Se encontró correlación moderada entre ambos MO, pero débil con DO alterada. Conclusiones: Se determinaron por primera vez rangos de B-CTx y N-MID en MPM chilenas, corroborando la similitud a otros países. Se encontraron valores discretamente más elevados de MO en grupo DO alterada, probablemente atribuible a causas secundarias no reportadas. Estos MO podrían constituir una herramienta complementaria a la DO y FRAX en la evaluación ósea.

Introduction: Bone densitometry (BD) has high specificity in the osteoporosis diagnosis but suboptimal sensitivity to estimate fracture risk. It was proposed that bone turnover markers (BTM) could be included in the osteoporosis risk algorithm, although the extent of its association is unknown. One recommended BTM to assess bone resorption is Beta-Cross Laps (B-CTx), while a BTM to assess bone formation is osteocalcin. Aims: To establish BCTx and N-MID osteocalcin (N-MID) ranges in postmenopausal women (PM) and compare BTM levels in two groups: control and with abnormal BD. Methods: PM with BD within the last year were recruited. A questionnaire of risk factors for fractures was applied, and BTM was measured. Volunteers with diseases that would affect bone remodeling were excluded. Results: 117 PM (57 control and 60 with abnormal BD) were recruited. 18% had osteoporosis, and the groups were comparable. The ranges for B-CTx and N-MID were 0.41 ± 0.18 [IC95% 0.37-0.45] and 22.76 ± 7.73 [IC95% 21.29-24.24] ng/mL. The mean levels of B-CTx and N-MID were higher in the group with abnormal BD (0.46 ± 0.19 and 24.29 ± 8.04 ng/mL). A moderate correlation between both BTM was found, but it was weak with abnormal BD. Conclusions: B-CTx and N-MID ranges were assessed for the first time in Chilean PM, similar to values found in other countries. Slightly higher values of BTM were found in the group with abnormal BD, which the presence of omitted secondary causes could explain. These BTM could be a complementary tool to BD and FRAX in bone evaluation.

Efectos de la microvibración y estrógeno en la remodelación ósea: revisión sistemática / Effects of micro-vibration and estrogen on bone: a systematic review

Introducción: la pérdida de hueso es un suceso que afecta a la totalidad del esqueleto. Así, las alteraciones musculoesqueléticas afectan a millones de personas en todo el mundo y están entre las causas más comunes de dolor crónico. Objetivo: conocer los efectos de la microvibración y estrógeno en el remodelado óseo. Material y métodos: se realizó una revisión sistemática, se buscó en siete bases de datos, se incluyeron estudios clínicos controlados realizados con ratas o ratones en el periodo de publicación del 2004 al 2022. La calidad de la evidencia sintetizada se evaluó con la escala de Jadad. Resultados: se identificaron quince artículos como estudios primarios. La microvibración reportó cambios in vivo/in vitro totalmente dependientes del estímulo que conlleva incremento de la cortical externa. A su vez, con la administración de estrógeno se reportaron efectos, específicamente, en el hueso trabecular y en el periostio, así como colágeno inmaduro que indican un recambio óseo. Conclusión: tanto la microvibración como la administración de estrógeno coadyuvan a la remodelación del tejido óseo y son aprovechables como tratamiento en el momento que exista un problema de pérdida ósea (AU)

Introduction: Bone loss is an event that affects the entire skeleton. Thus, musculoskeletal disorders affect millions of people worldwide and are among the most common causes of chronic pain. Objective: to know the effects of micro-vibration and estrogen on bone remodelling. Material and methods: a systematic review was carried out; seven databases were searched; Controlled clinical studies conducted with rats or mice in the publication period from 2004 to 2022 were included. The quality of the synthesized evidence was assessed using the Jadad scale. Results: fifteen articles were identified as primary studies. Micro vibration reported in vivo/in vitro changes dependent on the stimulus that entails an increase in the outer cortex. In turn, with the administration of estrogen, effects were reported, specifically in the trabecular bone and in the periosteum, as well as immature collagen that indicates bone turnover. Conclusion: both micro-vibration and the administration of estrogen contribute to the remodelling of bone tissue and are usable as a treatment for bone loss (AU)

Research progress on anterior alveolar bone changes after orthodontic treatment involving extractions / 口腔疾病防治

@#It has been traditionally believed that a 1:1 cortical bone remodeling/tooth movement ratio has been preserved during orthodontic treatment for tooth movement, with the alveolar bone on the tension side growing and the alveolar bone on the pressure side resorbing to maintain the balance of the alveolar bone. However, recent studies have shown that alveolar bone loss has been found in patients who have undergone orthodontic treatment, suggesting that the alveolar bone does not change as the teeth change over time. Whether the morphology of the alveolar bone will change when the anterior teeth are moved has been the clinical focus. The changes of anterior alveolar bone in patients who have undergone tooth extraction after orthodontic treatment were summerized by literature review in this paper. The results of the review showed that the alveolar bone at the lingual/palatal root-cervical site of the anterior root is more prone to bone loss after extensive movement of the anterior teeth. With the development of imaging technology, CBCT is now more commonly used for analysis instead of two-dimensional images for measurement, as its results are more accurate. However, there are few multifactorial studies in which CBCT has been used to assess the morphological changes in the alveolar bone. The focus of future research is to compare the long-term changes in the anterior alveolar bone of patients of different ages based on three-dimensional imaging, and to study the correlation between different skeletal features, tooth movement patterns and alveolar bone remodeling.

Histomorphological analysis of subchondral bone in hemophilic arthritis and osteoarthritis / 中华骨科杂志

Objective:To delineate the histomorphological disparities of subchondral bone between hemophilic arthritis (HA) and osteoarthritis (OA) and to explore the mechanisms underpinning aberrant bone remodeling in HA.Methods:Fifteen male HA patients, aged 32.60±7.58 years (range 22-45), who underwent total knee arthroplasty at the Second Affiliated Hospital of Anhui Medical University from January 2021 to June 2023, were included. All patients had hemophilia A and tested negative for coagulation factor VIII antibodies. Simultaneously, fifteen male OA patients, aged 75.67±5.09 years (range 71-87), also underwent arthroplasty. Tibial plateau bones were extracted for micro-CT, which assessed morphological parameters. Histological changes in the subchondral bone plate (SBP) and trabecular bone were evaluated with HE and Safranin O-Fast Green staining. TRAP staining determined osteoclast differentiation levels, and VEGF-A and Osterix immunohistochemistry gauged angiogenesis and osteoblast differentiation.Results:Micro-CT revealed that HA patients had a BV/TV of 25.14%±0.70% (medial) and 22.31%±0.53% (lateral), Conn.D. of 4.20±0.10 1/mm 3 (medial) and 3.27±0.08 1/mm 3 (lateral), BMD of 0.288±0.006 g/cm 3 (medial) and 0.285±0.004 g/cm 3 (lateral), Tb.Th of 0.257±0.008 mm (medial) and 0.206±0.008 mm (lateral), Tb.N of 0.984±0.043 1/mm (medial) and 0.908±0.026 1/mm (lateral), and Tb.Sp of 0.683±0.008 mm (medial) and 0.808±0.010 mm (lateral). These parameters were significantly lower than those in the OA group except for Tb.Sp, which was higher ( P<0.001). Histological staining indicated that the HA group's SBP thickness was 177.43±6.42 μm (medial) and 117.96±5.08 μm (lateral) with significant differences observed ( P<0.001). TRAP staining showed that TRAP + osteoclasts accounted for 33.4%±3.1% (medial) and 25.1%±2.3% (lateral) in HA subchondral bone, again significantly different ( P<0.001). Immunohistochemical staining revealed VEGFA + cells at 34.1%±5.9% (medial) and 25.9%±3.7% (lateral), and Osterix + cells at 14.6%±1.4% (medial) and 5.8%±1.1% (lateral) in HA patients, differing significantly from the OA group ( P<0.001). Conclusion:The HA group exhibited more extensive subchondral bone destruction, thinner trabeculae, a nearly absent tidemark, higher osteoclast differentiation, increased angiogenesis, and reduced osteoblast differentiation, indicating severe osteoporosis, despite thicker SBP. These findings suggest that targeting abnormal bone remodeling and angiogenesis in HA could retard its progression and provide therapeutic benefits.

Treatment of infected nonunion after internal fixation of subtrochanteric fracture with a reconstruction stent of external fixation / 中华创伤骨科杂志

Objective:To evaluate the treatment of infected nonunion after internal fixation of subtrochanteric fracture with a reconstruction stent of external fixation.Methods:A retrospective study was conducted to analyze the data of 5 male patients with infected nonunion after internal fixation of subtrochanteric fracture who had been treated and completely followed up at The Great Wall Orthopaedics and Hand Surgery Hospital from January 2017 to October 2022. The patients were (30.0±13.5) years old. Seinsheimer fracture types: ⅢA (1 case), ⅢB (1 case), Ⅳ (2 cases), and Ⅴ (1 case); original internal fixation: intramedullary system (4 cases) and plate fixation (1 case); the Cierny-Mader anatomical classification: type Ⅳ (diffuse type) for all. After complete debridement at stage one, 2 or 3 hydroxyapatite (HA) coated screws were placed at both fracture ends from the lateral side of the femur for unilateral reconstruction external fixation. Next, a hybrid external fixation scaffold was added with a 1/3 ring at the sagittal position and 1 or 2 HA screws in 4 cases while unilateral reconstruction external fixation was constructed at both sides by inserting 2 HA screws into both fracture ends from the anterior femur at the sagittal position in 1 case. Antibiotic bone cement was used to fill bone defects of (3.8±1.8) cm. At 6 to 8 weeks after debridement when infection did not recur, antibiotic bone cement was removed before autogenous iliac bone grafting was performed in 3 patients and osteotomy bone transport in 2 patients. Infection control, bone union time, time for removal of external fixation stent, complications, Sanders hip function score and Paley bone outcome score were recorded.Results:The 5 patients were followed up for (23.4±8.1) months after surgery. Infection at the fracture ends was controlled after 1 time of debridement in 3 patients and after 2 times of debridement in 2 patients. The loosening HA screws were replaced twice due to infection at the proximal nail tract, and autologous bone grafting was performed at the opposite fracture ends in 1 case; no complications occurred in the other 4 cases. Bony union was achieved at the extended segment and fracture ends in all patients. The time for imaging union after bone reconstruction was (10.2±3.4) months. The time for wearing a stent of external fixation was (18.0±4.5) months. There was no recurrent infection or lingering infection. According to the Sanders hip function score at the last follow-up, 4 cases were excellent and 1 case was good; according to the Paley bone outcome score, the curative effect was excellent in all.Conclusion:Application of a reconstruction stent of external fixation combined with antibiotic bone cement can control infection at the first stage and conduct bone reconstruction at the second stage to successfully treat the infected nonunion and preserve the hip function after internal fixation of subtrochanteric fracture.

Mid-term follow-up of reconstruction with liquid nitrogen-inactivated autologous bone graft in patients with diaphyseal malignant tumours / 中华骨科杂志

Objective:To explore the mid-term efficacy of liquid nitrogen-inactivated autologous tumor segment bone replantation for repairing bone defects after resection of malignant tumors in the long bone shaft.Methods:A retrospective analysis was performed on the clinical data of 16 patients treated with liquid nitrogen-inactivated autologous bone graft at Beijing Jishuitan Hospital from July 2015 to June 2017 to repair defects caused by malignant tumour resection of the diaphysis. There were 10 males and 6 females with a mean age of 23.4±11.6 years (range, 8-44 years), including 8 classic osteosarcoma, 2 high-grade surface osteosarcoma, 4 Ewing's sarcoma, 1 periosteal osteosarcoma, and 1 undifferentiated pleomorphic sarcoma. Tumors were located in the humerus in 2 cases, in the femur in 8 cases and in the tibia in 6 cases. The mean length of tumor was 12.4±4.8 cm (range, 5.5-26 cm). Postoperative imaging examination was performed every 6 months, and the healing status of the transplanted bone-host bone was evaluated based on the imaging assessment method of the International Society of Limb Salvage (ISOLS) imaging assessment after allogeneic bone transplantation, and the complications were assessed using the Henderson classification. The five-year survival rate for patients and grafted bone was calculated using the Kaplan-Meier survival curve.Results:The median follow-up was 64 (60.3, 69.8) months. At the end of follow-up, 13 patients were tumour free and 3 patients died of multiple metastases at 19, 20 and 33 months after surgery. There were 32 osteotomy ends in 16 patients, of which 30 healed, including 11 metaphyseal osteotomy ends, and the healing time was 9 (6, 12) months after replantation of the tumour segment with liquid nitrogen-inactivated autologous bone; 19 osteotomy ends in the diaphysis took 13 (9, 21) months to heal, with a statistically significant difference in healing time between different sites ( Z=-2.25, P=0.025). Sixteen patients had six complications, including two cases of non-union at the diaphyseal site, one case of failure of internal fixation due to non-union, three cases of recurrence, and no soft tissue complications or infections. One patient with failed internal fixation was treated with a vascularized tip iliac bone graft that healed 6 months after surgery. Another patient died of multiple metastases with 1 unhealed diaphysis left. Three cases of recurrence were all located in the extracranial soft tissue of the autologous tumor segment inactivated by liquid nitrogen. Among them, one case underwent reoperation and local radiotherapy, and there was still no tumor survival after 65 months of surgery, and two cases died due to multiple metastases. The five-year survival rate of patients was 81% as calculated using the Kaplan-Meier survival curve, and the graft survival rate was 100%. There was no amputation and the limb salvage rate was 100%. Conclusion:The use of liquid nitrogen-inactivated autologous tumor segment bone replantation for reconstruction of bone defects after resection of malignant tumors in the shaft has advantages of higher healing rate, shorter healing time at the metaphyseal end compared to the osteotomy end, fewer complications, and higher survival rate of the replanted bone.

Feasible low bone density condition for assessing bioactivity in ex-in vivo and in vivo studies

Abstract Objective To choose a critical animal model for assessments of bone repair with implant installation by comparing senile rats (SENIL) to young ovariectomized rats (OXV). Methodology For the ex-in vivo study, the femurs were precursors for bone marrow mesenchymal stem cells. Cellular responses were performed, including cell viability, gene expression of osteoblastic markers, bone sialoprotein immunolocalization, alkaline phosphatase activity, and mineralized matrix formation. For the in vivo study, the animals received implants in the region of the bilateral tibial metaphysis for histometric, microtomography, reverse torque, and confocal microscopy. Results Cell viability showed that the SENIL group had lower growth than OVX. Gene expression showed more critical responses for the SENIL group (p<0.05). The alkaline phosphatase activity obtained a lower expression in the SENIL group, as for the mineralization nodules (p<0.05). The in vivo histological parameters and biomechanical analysis showed lower data for the SENIL group. The confocal microscopy indicated the presence of a fragile bone in the SENIL group. The microtomography was similar between the groups. The histometry of the SENIL group showed the lowest values (p<0.05). Conclusion In experimental studies with assessments of bone repair using implant installation, the senile model promotes the most critical bone condition, allowing a better investigation of the properties of biomaterials and topographic changes.

Long-term consequences of osteoporosis therapy with denosumab

ABSTRACT Denosumab (DMAb) is a human monoclonal antibody used as an antiresorptive drug in the treatment of osteoporosis. Approval at a dosage of 60 mg every 6 months was based on the results of the randomized, placebo-controlled trial (FREEDOM). The design of this 3-year study included an extension for up to 10 years. Those who were randomized to DMAb continued on drug, while those who were randomized to placebo transitioned to DMAb. The 10-year experience with DMAb provides data on efficacy of drug in terms of reduced fractures and continued increases in bone mineral density (BMD). The 10-year experience with denosumab also provides information about rare complications associated with the use of DMAb, such as osteonecrosis of the jaw (ONJ), and atypical femoral fractures (AFF). This experience provided new insights into the reversibility of effects upon discontinuation without follow-on therapy with another agent. This review focuses upon prolonged treatment with DMAb, with regard to beneficial effects on fracture reduction and safety. Additionally, its use in patients with impaired renal function, compare its results with those of bisphosphonates (BPs), the occurrence/frequency of complications, in addition to the use of different tools, from imaging techniques to histological findings, to evaluate its effects on bone tissue.

Genetic, Cellular and Molecular Aspects involved in Apical Periodontitis

Abstract The development, establishment and repair of apical periodontitis (AP) is dependent of several factors, which include host susceptibility, microbial infection, immune response, quality of root canal treatment and organism's ability to repair. The understanding of genetic contributions to the risk of developing AP and presenting persistent AP has been extensively explored in modern Endodontics. Thus, this article aims to provide a review of the literature regarding the biochemical mediators involved in immune response signaling, osteoclastogenesis and bone neoformation, as the genetic components involved in the development and repair of AP. A narrative review of the literature was performed through a PUBMED/MEDLINE search and a hand search of the major AP textbooks. The knowledge regarding the cells, receptors and molecules involved in the host's immune-inflammatory response during the progression of AP added to the knowledge of bone biology allows the identification of factors inherent to the host that can interfere both in the progression and in the repair of these lesions. The main outcomes of studies evaluated in the review that investigated the correlation between genetic polymorphisms and AP in the last five years, demonstrate that genetic factors of the individual are involved in the success of root canal treatment. The discussion of this review gives subsides that may help to glimpse the development of new therapies based on the identification of therapeutic targets and the development of materials and techniques aimed at acting at the molecular level for clinical, radiographic and histological success of root canal treatment.

Resumo O desenvolvimento, estabelecimento e reparo da periodontite apical (PA) depende de vários fatores, que incluem a susceptibilidade do hospedeiro, infecção microbiana, resposta imune, bem como a qualidade do tratamento do canal radicular e a capacidade de reparo do organismo. A compreensão das contribuições genéticas para o risco de desenvolver a PA e apresentar PA persistente tem sido extensivamente explorada na Endodontia moderna. Assim, este manuscrito pretende fornecer uma revisão da literatura em relação aos mediadores bioquímicos envolvidos na sinalização da resposta imune, osteoclastogênese e neoformação óssea, bem como os componentes genéticos envolvidos no desenvolvimento e reparo da PA. Uma revisão narrativa da literatura foi realizada através de uma pesquisa nas bases PUBMED/MEDLINE e uma pesquisa manual nos principais livros sobre a PA. O conhecimento sobre as células, receptores e moléculas envolvidas na resposta imuno-inflamatória do hospedeiro durante a progressão da PA somado ao conhecimento da biologia óssea, especialmente o papel dos osteoblastos, osteócitos e osteoclastos no turnover ósseo, permite a identificação de fatores inerentes ao hospedeiro que podem interferir tanto na progressão como no reparo destas lesões. Os principais resultados dos estudos avaliados na revisão que investigaram a correlação entre polimorfismos genéticos e PA, nos últimos cinco anos, demonstram que os fatores genéticos do indivíduo estão envolvidos no sucesso do tratamento do canal radicular. A discussão desta revisão fornece subsídios que podem ajudar a vislumbrar o desenvolvimento de novas terapias baseadas na identificação de alvos terapêuticos e no desenvolvimento de materiais e técnicas destinadas a atuar a nível molecular para o sucesso clínico, radiográfico e histológico do tratamento endodôntico.

Advances in immunoporosis / 中华内分泌代谢杂志

Osteoporosis is a common metabolic bone disease, which is involved in disrupted normal bone remodeling process and bone resorption exceeding bone formation. Osteoblasts and osteoclasts play critical roles in maintaining bone homeostasis. In recent years, more and more studies have found that immune cells are involved in the regulation of osteoblast and osteoclast activity via releasing various chemokines and cytokines, and the concept of immunoporosis has been proposed accordingly. This article summarizes the current state of knowledge on the immune system in the pathophysiology of osteoporosis, so as to study and prevent osteoporosis from the perspective of immunology.

Experimental study on the regulation of subchondral bone plate osteoprotegerin/receptor activator of nuclear factor kappa-B ligand system by berberine to retard the development of osteoarthritis in rabbits / 中国骨伤

OBJECTIVE@#To investigate the effect of intra-articular berberine injection on the structural remodeling of subchondral bone plate and osteoprotegerin/receptor activator of nuclear factor kappa-B ligand(OPG/RANKL) system expression in rabbits with osteoarthritis(OA).@*METHODS@#Forty 12-month-old male rabbits with an average of(2.73±0.18) kg of body weight, underwent left anterior cruciate ligament transection(ACLT), and were divided into berberine group and placebo groups after operation, 20 rabbits in each group. The berberine group received intra-articular injection of 100 μmol/L berberine 0.3 ml every week for 6 weeks. In placebo group, the same dose of 0.9% sodium chloride injection was injected into the left knee joint cavity every week for 6 weeks. Another 20 12-month-old male rabbits, weighing (2.68±0.18) kg, underwent sham operation on the left knee joint without intra-articular injection intervention (sham operation group). On the last day of the sixth week after operation, three groups of animals were sacrificed to obtain knee joint specimens. The femoral medial condyle samples were obtained for histological evaluation of cartilage and subchondral bone, Mankin scoring system was used to evaluate articular cartilage structure. Image-Pro Plus(IPP) software was used to evaluate subchondral bone plate bone volume(BV), bone volume/total volume(BV/TV), trabecular circumference(TC), mean trabecular thickness (Tb.Th). Real-time quantitative reverse transcription polymerization Enzyme chain reaction(reverse transcription-polymerase chain reaction, RT-PCR) was used to detect the mRNA expression levels of OPG and RANKL in subchondral bone tissue at 6 weeks after operation.@*RESULTS@#The cartilage structure evaluation showed that the surface of cartilage tissue in the sham operation group was smooth and flat, and the safranin coloration was full in the full thickness of the cartilage;the cartilage tissue in the berberine group showed uneven surface layer, and the staining of safranin O was mildly decreased;the surface layer fibrosis was seen in placebo group, Safranin O faded significantly. The Mankin score in the berberine group was lower than that in placebo group(P<0.01), but higher than that in sham operation group(P<0.01). The structural evaluation of subchondral bone plate showed that the trabecular bone in sham-operated group was densely arranged;after berberine intervention, the trabeculae were closely arranged;the subchondral bone trabeculae in placebo group were relatively sparse, and the distance between trabeculae was wider. Subchondral bone plate IPP software evaluation showed that BV, BV/TV, TC, Tb.Th in berberine group were higher than those in placebo group(P<0.01), BV, BV/TV, TC, Tb.Th in berberine group were higher than those in placebo group(P<0.01), while lower than the sham operation group (P<0.01). PCR test results showed that the expression of OPG mRNA in the berberine group was significantly higher than that in placebo group(P<0.01), and OPG mRNA in the berberine group was lower than that in sham operation group (P<0.01). There was no significant difference in mRNA expression of RANKL among three groups(P>0.05);the ratio of OPG/RANKL in berberine group was higher than that in placebo group(P<0.01), but lower than that in sham operation group(P<0.01).@*CONCLUSION@#Intra-articular injection of berberine can effectively inhibit the resorption of subchondral bone in the early stage of OA and delay the development of the disease. The specific mechanism may be that berberine maintains the balance of OPG/RANKL system by up-regulating the expression of OPG gene in subchondral bone.

Effects of Total Hip Arthroplasty on Proximal Femoral Bone Remodeling / 医用生物力学

Objective To analyze the influence of total hip arthroplasty (THA) on the process of proximal femoral bone remodeling by using the Wolff bone remodeling theory. Methods According to control equation of bone remodeling, the program of bone remodeling was written in Python language. Preoperative femur model and postoperative femur and prosthesis finite element models were established respectively in ABAQUS software. The process of bone reconstruction before and after THA operation was compared to analyze the effect of prosthesis implantation on mechanical properties of the femur in the middle and long term after THA operation. Results The stress in proximal femur continued to decrease after prosthesis implantation, and the stress site was transferred from the femoral head to the prosthesis, resulting in an obvious stress shielding phenomenon. Bone loss in the stress shielding area was serious. The femoral shaft cortical bone became thinner and the stress shielding was relieved. The medial side at the bottom of the prosthesis was compressed, and the stress was significantly higher than that of the lateral side, where the bone was unevenly distributed. Conclusions After THA operation, obvious stress shielding occured at proximal medial side of the femur, leading to bone loss and prosthesis loosening. The difference in stress levels on both sides at the bottom of the prosthesis resulted in an uneven bone distribution, causing the discordance between the prosthesis and the femur, as well as postoperative pain in the middle part of the thigh.