Genetic Signature for the Causation of Charcot Neuro-osteoarthropathy of Foot in Diabetes: A Systematic Review.

Charcot neuro-osteoarthropathy (CNO) is a complication of diabetes occurring in people with diabetic neuropathy with a prevalence of 0.5% to 1% that may culminate to foot deformity, amputation, and early mortality. However, it is not known why only certain patients with diabetic neuropathy develop CNO. Hence, early recognition of risk factors, timely diagnosis, and appropriate intervention of CNO is pertinent. Recent understanding of the pathophysiology of CNO has expanded to suggest the involvement of RANKL-OPG pathways. But pharmaco-therapeutic interventions targeting bone metabolism predominantly inhibiting RANKL were not found to be useful. Moreover, there are not enough markers to help identify patients with diabetes who are at a higher risk of developing CNO. Hence, we explored the literature in the present systematic review of mainly case-control studies to identify genetic factors that could help in understanding the pathophysiology and risk factors for the development of CNO. We could identify 7 relevant studies identifying single nucleotide polymorphism of OPG and RANK genes. There is an isolated study identifying alterations of micro RNA associated with RANKL-OPG pathway. Another study found epigenetic alterations by performing whole methylome sequencing in people with CNO compared to control. These genetic factors can be used as a diagnostic marker and their functional counterparts as targets for future therapeutic interventions. However, we found that literature is sparse on the genetic risk factors for CNO in people with diabetic neuropathy and there is still a lot of scope for future studies towards finding the molecular and genetic markers for CNO.

Prophylactic and therapeutic effects of (6)-shogaol on alveolar bone loss in experimental periodontitis.

Purpose: (6)-Shogaol is the most prevalent bioactive compound in ginger. The aim of this study was to examine both the prophylactic and therapeutic effects of (6)-shogaol in an experimental periodontitis model. Materials and methods: Thirty-five male Wistar albino rats were divided into four groups. In the healthy group (n=5), no intervention was undertaken. In the periodontitis group (n=10), periodontitis was induced by ligature placement for 14 days. In the prophylaxis group (n=10), periodontitis was induced with ligature placement for 14 days, and during this time, 20 mg/kg/day of (6)-shogaol was administered via oral gavage. In the therapeutic group (n=10), periodontitis was induced with ligature placement for 14 days, and following the removal of the ligature, 20 mg/kg/day of (6)-shogaol was administered via oral gavage for 14 days. Alveolar bone loss was histometrically measured, and malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (GP), nuclear factor kappa B (NF-κB), receptor activator of nuclear factor kappa B ligand (RANKL), and osteoprotegerin (OPG) were immunohistochemically analyzed. Results: Alveolar bone loss was significantly lower in the healthy group than in the remaining groups, as well as in the therapeutic group than in the periodontitis group (p<0.001). RANKL/OPG was significantly higher in the periodontitis group compared to the remaining groups and in the prophylaxis group compared to the therapeutic group (p<0.001). MDA was significantly lower in the healthy group than in the remaining groups (p<0.001). SOD was significantly lower in the periodontitis group than in the prophylaxis and therapeutic groups (p=0.039 and p=0.042, respectively). GP was significantly lower in the healthy group than in the prophylaxis and therapeutic groups (p=0.031 and p=0.002, respectively). Conclusion: The administration of (6)-shogaol modulated the RANKL/OPG balance and antioxidant status in rats with ligature-induced periodontitis.

Melittin Treats Periprosthetic Osteolysis in a Rat Model by Inhibiting the NF-kB Pathway and Regulating the Ratio of Receptor Activator of Nuclear Factor Kappa B Ligand/Osteoprotegerin.

BACKGROUND: Aseptic loosening around the prosthesis is a common cause of failure in total joint arthroplasty. Polyethylene wear particles trigger the release of inflammatory factors by macrophages. Key mediators involved in osteoclastogenesis include interleukin-6, tumor necrosis factor-α, receptor activator of nuclear factor kappa B (RANK), RANK ligand (RANKL), and bone protection hormone (Osteoprotegerin [OPG]). The purpose of our experiment was to see whether melittin can slow down the release of inflammatory mediators through the NF-kB pathway, regulate the RANKL/OPG ratio, reduce osteoclast formation, and delay the onset of arthritis in rats. METHODS: A total of 20 male Sprague-Dawley rats (10 months, Specific Pathogen Free, 350 g ± 20 g) were randomly divided into 5 groups: sham group, model group, melittin concentration 1 group (0.2 mg/kg), concentration 2 group (0.4 mg/kg), and concentration 3 group (0.6 mg/kg). All rats were implanted with TA2 high-purity titanium rods. A drill was used to create a bone canal along the long axis of the femur in the intercondylar notch. The model group and experimental groups were exposed to polyethylene particles, while the sham group did not receive any particles. RESULTS: The melittin group exhibited significantly increased serum levels of serum P, calcium-phosphorus product, OPG, PINP, PINP/CTX-I, and OPG/RANKKL (P < .05). In the experimental group, micro computed tomography scanning results revealed a decrease in the amount of bone defect around the prosthesis. Immunofluorescence analysis demonstrated a decrease in the expression of IKKα and P65, while the expression of OPG showed an upward trend. Both Hematoxylin-Eosin and Tartrate-Resistant Acid Phosphatase staining revealed less osteoclast and inflammatory cell infiltration in bone resorption pits. CONCLUSIONS: Our study demonstrates that melittin has the ability to inhibit the NF-kB pathway in a rat model, and reduce the impact of RANKL/OPG, thereby delaying osteoclast activity and alleviating periprosthetic osteolysis.

The Role of the Receptor Activator of Nuclear Factor Kappa-B Ligand/Osteoprotegerin Ratio in Vascular Diseases: A Therapeutic Approach.

Cardiovascular and bone diseases contribute independently to mortality and global health. The exact mechanisms involved in the pathophysiology shared between bone and vascular diseases are not well defined. Endothelial cells and osteoblasts communicate during osteogenesis, thus establishing a connection between angiogenesis and osteogenesis. One shared mechanism may involve osteoprotegerin (OPG) and its ligand Receptor Activator of NF-κB Ligand (RANKL). The RANKL/OPG ratio is an important modulator for the skeletal, immunological, and vascular systems. OPG levels are elevated due to either osteogenic causes or inflammatory responses in the vasculature. The data obtained from clinical and in vitro studies support the role of the RANKL/OPG ratio as a potential marker for the progression of endothelial damage. Therefore, determining the therapeutic approaches for the targeting RANKL/OPG ratio and evaluating its usage as a biomarker in cardiovascular and bone pathophysiology are needed. By integrating the protective and disease-causing role of OPG with its ligand, this review outlines the role of the RANKL/OPG ratio at the molecular level. We also consider targeted therapeutic approaches.

Marantodes pumilum (Kacip Fatimah) Aqueous Extract Enhances Osteoblast and Suppresses Osteoclast Activities in Cancellous Bone of a Rat Model of Postmenopause.

Evidence pointed towards the benefits of Marantodes pumilum in treating osteoporosis after menopause; however, the detailed mechanisms still have not been explored. Therefore, this study aims to identify the molecular mechanisms underlying M. pumilum's bone-protective effect via the involvement of RANK/RANKL/OPG and Wnt/ß-catenin signaling pathways. Ovariectomized adult female rats were given M. pumilum leaf aqueous extract (MPLA) (50 and 100 mg/kg/day) and estrogen (positive control) orally for twenty-eight consecutive days. Following the treatment, rats were sacrificed, and femur bones were harvested. Blood was withdrawn for analysis of serum Ca2+, PO43-, and bone alkaline phosphatase (BALP) levels. The bone microarchitectural changes were observed by H&E and PAS staining and distribution and expression of RANK/RANKL/OPG and Wnt3a/ß-catenin and its downstream proteins were determined by immunohistochemistry, immunofluorescence, Western blot, and real-time PCR. MPLA treatment increased serum Ca2+ and PO43- levels and reduced serum BALP levels (p < 0.05). Besides, deterioration in cancellous bone microarchitecture and the loss of bone glycogen and collagen content were mitigated by MPLA treatment. Levels of RANKL, Traf6, and NF-kB but not RANK in bone were decreased; however, levels of OPG, Wnt3a, LRP-5, Frizzled, Dvl, ß-catenin, RUNX, and Bmp-2 in bone were increased following treatment with MPLA. In conclusion, MPLA helps to protect against bone deterioration in estrogen deficiency state and thus, this herb could potentially be used to ameliorate osteoporosis in women after menopause.

Lanthanum Hydroxide and Chronic Kidney Disease Mineral and Bone Disorder: A Rat Model.

OBJECTIVE: To investigate the pharmacological effects and molecular mechanisms of lanthanum hydroxide(LH) on ectopic mineralization of soft tissue and abnormal bone in rats with acute kidney injury(AKI). METHODS: Wistar rats were modeled by 5/6 nephrectomy. After the operation, the rats were divided into different groups, the biochemical indexes of serum collected at different times. Lanthanum hydroxide was administered by intragastric tube at doses of 0.4, 0.2, and 0.1g/kg, respectively. Rats were sacrificed in the 16th week after LH treatment. Observation of pathological changes in tissues were made by specific staining. Western Blot, Real-Time Quantitative PCR, and immunohistochemistry techniques were used to detect the impact on pathway-related proteins. RESULTS: Compared with the control group (no LH administered), the serum phosphate level of the LH group was significantly reduced (P<0.01), calcification of the thoracic aorta was reduced (P<0.05, P<0.01) (Serum biochemical tests before dosing and during drug treatment cycles), renal fibrosis was improved (P<0.01), nuclear entry of nuclear factor kappa-B (NF-κB) was reduced (P<0.01), and the expression of the smooth muscle protein 22α (SM22α) was significantly increased (P<0.01). The expression of osteogenic marker genes was decreased. In addition, compared with the controls, the receptor activator for nuclear factor-κB ligand/osteoprotegerin (RANKL/OPG) ratio of the femur in the model group was increased (P<0.05). CONCLUSION: LH can inhibit the occurrence and development of vascular calcification and bone abnormalities in AKI rats by inhibiting the NF-κB and RANKL/OPG signaling pathways.

Investigating the therapeutic potential of sinomenine in rheumatoid arthritis: anti-inflammatory, antioxidant, and immunomodulatory mechanisms.

An autoimmune disease, rheumatoid arthritis (RA) is characterized by the onset of inflammation and subsequent damage to the joints. Although several therapies are available for RA, none are effective, and many have undesirable side effects. The roots of Sinomenium acutum produce an alkaloid called Sinomenine (SIN), which has been used for centuries in Chinese medicine to treat arthritis due to its anti-inflammatory properties. This study aimed to explore the potential therapeutic benefits of SIN through oral administration following RA induction using Freund's complete adjuvant (FCA) injections. The study monitored changes in the arthritic index, hind paw volume, inflammation and oxidative stress markers. Results demonstrated that SIN effectively inhibited the activity of NF-κB and IKKß in knee joint tissues, which led to a decrease in tissue levels of TNF-α, IL-6, IL-1ß, and iNOS in RA-induced rats. The production of anti-inflammatory cytokines such as IL-10, Arg-1, and Fizz1 also increased. In rat knee joints, SIN elevated the expression of TIMP-1 and TIMP-3 and decreased the expression of MMP-2 and MMP-9. Additionally, SIN modulated the RANK/RANKL/OPG pathway in RA-induced rat knee joint tissues, reducing RANKL expression and increasing OPG. SIN also effectively decreased MDA, NO, and elevated antioxidant enzymes (SOD, CAT, GPx, and GSH) in RA-induced rats via Nrf2/Keap 1 signaling pathway activation. In conclusion, this study suggests that SIN possesses potential therapeutic benefits for treating RA by modulating the RANK/RANKL/OPG pathway, which may impact osteoclast activity, oxidative stress, and inflammation in knee joint tissues.

Absence of melatonin during development impairs craniofacial and dental onset in rats.

OBJECTIVE: Herein, we evaluated pinealectomy-induced melatonin absence to determine its effects on craniofacial and dental development in the offspring. DESIGN: Female Wistar rats in three groups, i.e., intact pregnant rats, pinealectomized pregnant rats (PINX), and pinealectomized pregnant rats subjected to oral melatonin replacement therapy, were crossed 30 days after surgery. The heads of 7-day-old pups were harvested for cephalometric and histological analyses, and maxillae and incisors were collected for mRNA expression analysis. RESULTS: The PINX pups exhibited a reduction in neurocranial and facial parameters such as a decrease in alveolar bone area, incisor size and proliferation, and an increase in odontoblasts and the dentin layer. Based on incisor mRNA expression analysis, we found that Dmp1 expression was upregulated, whereas Col1a1 expression was downregulated. Maxillary mRNA expression revealed that Rankl expression was upregulated, whereas that of Opn and Osx was downregulated. CONCLUSION: Our results demonstrated that the absence of maternal melatonin during early life could affect dental and maxillary development in offspring, as well as delay odontogenesis and osteogenesis in maxillary tissues. CLINICAL RELEVANCE: Our findings suggest that disruptions or a lack of melatonin during pregnancy may cause changes in craniofacial and dental development, at least in animal experiments; however, in humans, these feedings are still poorly understood, and thus careful evaluations of melatonin levels in humans need to be investigated in craniofacial alterations.

Current comprehensive understanding of denosumab (the RANKL neutralizing antibody) in the treatment of bone metastasis of malignant tumors, including pharmacological mechanism and clinical trials.

Denosumab, a fully humanized monoclonal neutralizing antibody, inhibits activation of the RANK/RANKL/OPG signaling pathway through competitive binding with RANKL, thereby inhibiting osteoclast-mediated bone resorption. Denosumab inhibits bone loss; therefore, it is used to treat metabolic bone diseases (including postmenopausal osteoporosis, male osteoporosis, and glucocorticoid-induced osteoporosis), in clinical practice. Since then, multiple effects of denosumab have been discovered. A growing body of evidence suggests that denosumab has a variety of pharmacological activities and broad potential in clinical diseases such as osteoarthritis, bone tumors, and other autoimmune diseases. Currently, Denosumab is emerging as a treatment for patients with malignancy bone metastases, and it also shows direct or indirect anti-tumor effects in preclinical models and clinical applications. However, as an innovative drug, its clinical use for bone metastasis of malignant tumors is still insufficient, and its mechanism of action needs to be further investigated. This review systematically summarizes the pharmacological mechanism of action of denosumab and the current understanding and clinical practice of the use of denosumab for bone metastasis of malignant tumors to help clinicians and researchers deepen their understanding of denosumab.

Diosmin mitigates dexamethasone-induced osteoporosis in vivo: Role of Runx2, RANKL/OPG, and oxidative stress.

Secondary osteoporosis is commonly caused by long-term intake of glucocorticoids (GCs), such as dexamethasone (DEX). Diosmin, a natural substance with potent antioxidant and anti-inflammatory properties, is clinically used for treating some vascular disorders. The current work targeted exploring the protective properties of diosmin to counteract DEX-induced osteoporosis in vivo. Rats were administered DEX (7 mg/kg) once weekly for 5 weeks, and in the second week, vehicle or diosmin (50 or 100 mg/kg/day) for the next four weeks. Femur bone tissues were collected and processed for histological and biochemical examinations. The study findings showed that diosmin alleviated the histological bone impairments caused by DEX. In addition, diosmin upregulated the expression of Runt-related transcription factor 2 (Runx2) and phosphorylated protein kinase B (p-AKT) and the mRNA transcripts of Wingless (Wnt) and osteocalcin. Furthermore, diosmin counteracted the rise in the mRNA levels of receptor activator of nuclear factor-kB ligand (RANKL) and the reduction in osteoprotegerin (OPG), both were induced by DEX. Diosmin restored the oxidant/antioxidant equilibrium and exerted significant antiapoptotic activity. The aforementioned effects were more pronounced at the dose level of 100 mg/kg. Collectively, diosmin has proven to protect rats against DEX-induced osteoporosis by augmenting osteoblast and bone development while hindering osteoclast and bone resorption. Our findings could be used as a stand for recommending supplementation of diosmin for patients chronically using GCs.

Levels of Pro-Inflammatory and Bone-Resorptive Mediators in Periodontally Compromised Patients under Orthodontic Treatment Involving Intermittent Forces of Low Intensities.

During orthodontic treatment, diverse cytokines, enzymes, and osteolytic mediators produced within the teeth surrounding periodontal tissues determine the rate of alveolar bone remodeling and consequent teeth movement. In patients with teeth presenting reduced periodontal support, periodontal stability should be ensured during orthodontic treatment. Thus, therapies based on the application of low-intensity intermittent orthodontic forces are recommended. To determine if this kind of treatment is periodontally well tolerated, this study aimed to analyze the production of receptor activator of nuclear factor kappa-B ligand (RANKL), osteoprotegerin (OPG), interleukin (IL)-6, IL-17A, and matrix metalloproteinase (MMP)-8 in periodontal tissues of protruded anterior teeth with reduced periodontal support and undergoing orthodontic treatment. Patients with periodontitis-associated anterior teeth migration received non-surgical periodontal therapy and a specific orthodontic treatment involving controlled low-intensity intermittent orthodontic forces. Samples were collected before periodontitis treatment, after periodontitis treatment, and at 1 week to 24 months of the orthodontic treatment. During the 2 years of orthodontic treatment, no significant differences were detected in the probing depth, clinical attachment level, supragingival bacterial plaque, and bleeding on probing. In line with this, the gingival crevicular levels of RANKL, OPG, IL-6, IL-17A, and MMP-8 did not vary between the different evaluation time-points of the orthodontic treatment. When compared with the levels detected during the periodontitis, the RANKL/OPG ratio was significantly lower at all the analyzed time-points of the orthodontic treatment. In conclusion, the patient-specific orthodontic treatment based on intermittent orthodontic forces of low intensities was well tolerated by periodontally compromised teeth with pathological migration.

Breast Cancer Exosomal microRNAs Facilitate Pre-Metastatic Niche Formation in the Bone: A Mathematical Model.

Pre-metastatic niche is a location where cancer cells, separating from a primary tumor, find "fertile soil" for growth and proliferation, ensuring successful metastasis. Exosomal miRNAs of breast cancer are known to enter the bone and degrade it, which facilitates cancer cells invasion into the bone interior and ensures its successful colonization. In this paper, we use a mathematical model to first describe, in health, the continuous remodeling of the bone by bone-forming osteoblasts, bone-resorbing osteoclasts and the RANKL-OPG-RANK signaling system, which keeps the balance between bone formation and bone resorption. We next demonstrate how breast cancer exosomal miRNAs disrupt this balance, either by increasing or by decreasing the ratio of osteoclasts/osteoblasts, which results in abnormal high bone resorption or abnormal high bone forming, respectively, and in bone weakening in both cases. Finally we consider the case of abnormally high resorption and evaluate the effect of drugs, which may increase bone density to normal level, thus protecting the bone from invasion by cancer cells.

Trends in the pathophysiology of Charcot neuroarthropathy.

The pathophysiology of Charcot neuroarthropathy (CN) includes a number of gray areas, particularly regarding the onset of inflammation which induces the disruption of the bone remodeling factor responsible for the onset of bone lysis. This clinical insight highlights a potential link between this inflammation and the rapid correction of chronic hyperglycemia (Dardari et al., 2022), which is known to be responsible for a particular type of neuropathy known as treatment-induced neuropathy of diabetes (TIND). Our description makes an additional contribution to shed light on the mysterious physiopathology of CN.

Effects of bone marrow mesenchymal stem cell transplantation on bone metabolism and RANKL/OPG/TRAF6 signaling pathway in osteoporotic rats / 中华内分泌外科杂志

Objective:To investigate the effect of bone marrow derived mesenchymal stem cells (BMSC) transplantation on bone metabolism and its mechanism in ovariectomized osteoporosis rats.Methods:Forty clean SD female rats aged 7 weeks were divided into 4 groups according to the random number table method: sham operation group, model group, the transplantation group, positive control group, in addition to control the rest of the group were performed bilateral oophorectomy build osteoporosis rats model, after 2 months of model establishment, rats in transplantation group were injected with 80 μl/kg PBS solution containing bone marrow mesenchymal stem cells through tail vein, rats in sham operation group and model group were injected with the same amount of PBS solution through tail vein, and rats in positive control group were given Xianlinggubao (0.5 g/100 g) by gavage every day. Serum and femur were collected 14 days after treatment. Hematoxylin and eosin staining (HE) was used to observe the histopathological changes of femur. Micro-CT was used to measure bone mineral density and bone parameters. The expression levels of osteocalcin, osteoprotegerin, alkaline phosphatase and insulin-like growth factor 1 were detected by enzyme-linked immunosorbent assay (ELISA) kit. The serum levels of calcium, phosphorus and magnesium were measured by spectrophotometer. The protein expressions of RANKL, OPG, TRAF6 and NF-KB1 in femur of each group were detected by Western blot.Results:Compared with the sham operation group, the bone mineral density (BMD) of the model group was decreased by (0.28±0.01) g/cm 3, bone volume fraction (BMD) was decreased by (0.28±0.01) g/cm 3. BV/TV) decreased by (19.73±2.02) %, trabecular thickness (Tb.Th) decreased by (0.082±0.008) mm, trabecular number (Tb.N) decreased by (1.60±0.17) mm -1 and trabecular separation/spacing (Tb.Sp) increased (0.273±0.024) mm, osteoprotegerin (489.49±55.29) ng/L, alkaline phosphatase (229.13±15.05) U/L, insulin-like growth factor-1 (236.64±14.32) μg/L, and osteocalcin were decreased (1.866±0.109) μg/L, calcium (11.98±1.09) mg/dl, phosphorus (6.85±0.68) mg/dl, and magnesium decreased (0.62±0.04) mg/dl) , the relative expression level of RANKL increased (1.05±0.09) , the relative expression level of OPG decreased (0.58±0.08) , the relative expression level of RANKL increased (0.74±0.10) , and the relative expression level of NF-kB1 increased (1.01±0.11) ( P<0.05) ; bone mineral density, bone mineral density, bone mineral density BMD (0.38±0.04 g/cm 3, BV/TV (26.73±2.74) %, Tb.Th (0.094±0.006) mm, Tb.N (2.67±0.09) mm-1 and Tb.Sp were decreased (0.241±0.026) mm) , osteoprotegerin (720.09±67.41) ng/L, alkaline phosphatase (269.48±14.15) U/L, insulin-like growth factor 1 (IGF-1) decreased (335.95±24.13) μg/L, and osteocalcin increased (1.392±0.153) μg/L, calcium (7.12±0.53) mg/dl, phosphorus (4.54±0.32) mg/dl, magnesium (0.87±0.08) mg/dl. RANKL relative expression level increased (0.59±0.05) , OPG relative expression level decreased (0.97±0.10) , RANKL relative expression level increased (0.45±0.06) , NF-kB1 relative expression level increased (0.72±0.06) ( P<0.05) ;bone mineral density, bone mineral density, bone mineral density BMD (0.36±0.05) g/cm 3, BV/TV (28.72±3.20) %, Tb.Th (0.096±0.011) mm, Tb.N (2.85±0.24) mm -1 Tb.Sp was basically unchanged (0.241±0.027) mm, osteoprotegerin was decreased (716.78±36.90) ng/L, alkaline phosphatase was basically unchanged (270.65±18.59) U/L, and insulin-like growth factor 1 was decreased (336.94±17.50) μg/L, osteocalcin (1.377±0.101) μg/L, calcium (7.13±0.80) mg/dl, phosphorus (4.58±0.71) mg/dl, and magnesium (0.89±0.04) remained unchanged mg/dl, the relative expression level of RANKL increased (0.55±0.08) , the relative expression level of OPG decreased (0.98±0.13) , the relative expression level of RANKL was basically unchanged (0.40±0.05) , and the relative expression level of NF-kB1 increased (0.65±0.09) ( P<0.05) . Conclusion:Bone marrow mesenchymal stem cell transplantation can improve osteoporosis in ovariectomized rats by regulating bone metabolism and serum levels of calcium, phosphorus and magnesium, which may be related to RANKL/OPG/TRAF6 pathway.

Traditional Chinese Medicine Intervenes in Signaling Pathways Associated with CKD-MBD： A Review / 中国实验方剂学杂志

Traditional Chinese medicine （TCM） has certain advantages in the treatment of chronic kidney disease-mineral and bone disorder （CKD-MBD）. In recent years， there have been many studies on the treatment of CKD-MBD by Chinese medicinal compounds and monomers. As revealed by literature retrieval， the research on the mechanism of Chinese medicine in intervening in signaling pathways related to CKD-MBD was mainly based on self-made Chinese medicinal compounds， and the action pathways involved fibroblast growth factor 23/Klotho （FGF23/Klotho） signaling pathway， Wnt/β-catenin signaling pathway， receptor activator of nuclear factor-κB/receptor activator of nuclear factor-κB ligand/osteoprotegerin （RANK/RANKL/OPG） system， and other signaling pathways. TCM can improve calcium and phosphorus metabolism and bone metabolism disorder， and regulate inflammatory reaction， oxidative stress， apoptosis， and autophagy by regulating this series of signaling pathways for the treatment of CKD-MBD. This paper introduced the research results of these signaling pathways and the mechanism of TCM in the treatment of CKD-MBD in order to provide ideas and references for the related research of Chinese medicine in the treatment of CKD-MBD.

Alterations in bone fracture healing associated with TNFRSF signaling pathways.

Bone fracture healing is a complex process involving various signaling pathways. It remains an unsolved issue the fast and optimal management of complex or multiple fractures in the field of orthopedics and rehabilitation. Bone fracture healing is largely a four-stage process, including initial hematoma formation, intramembrane ossification, chondrogenesis, and endochondral ossification followed by further bone remodeling. Many studies have reported the involvement of immune cells and cytokines in fracture healing. On the other hand, the Tumor Necrosis Factor (TNF) family and TNF receptor superfamily (TNFRSF) play a pivotal role in many physiological processes. The functions of the TNF family and TNFRSF in immune processes, tissue homeostasis, and cell differentiation have been extensively studied by many groups, and treatments targeting specific TNFRSF members are in progress. In terms of bone fracture management, it has been discovered that several members of TNFRSF have very distinct functions in different stages of fracture healing, including TNFR1, TNFR2, and receptor activator of nuclear factor kappa-B (RANK) pathways. More specifically, TNFR1 is associated with osteoclastogenesis and TNFR2 is associated with osteogenic differentiation, while RANK is in association with bone remodeling. In this review, we will discuss and summarize the involvement of members of TNFRSF including TNFR1, TNFR2, and Receptor activator of nuclear factor kappa-B (RANK) pathways in different stages of fracture healing and bone remodeling and the current treatment trend involving TNFRSF agonists and antagonists.

Lacticaseibacillus rhamnosus MG4706 Suppresses Periodontitis in Osteoclasts, Inflammation-Inducing Cells, and Ligature-Induced Rats.

Periodontitis is a chronic inflammatory disease characterized by tooth loss due to inflammation and the loss of alveolar bone. Periodontitis is closely related to various systemic diseases and is emerging as a global health problem. In this study, we investigated the anti-inflammatory effect of lactic acid bacteria (LAB) in vitro on Porphyromonas gingivalis (P. gingivalis) LPS-activated RAW264.7 and human gingival fibroblasts-1 (HGF-1) cells and the anti-osteoclastogenic effect of LAB on RANKL-induced RAW264.7 cells. All LAB strains (Lacticaseibacillus rhamnosus MG4706, MG4709, and MG4711) inhibited nitric oxide (NO)/inducible nitric oxide synthase (iNOS) in P. gingivalis LPS-activated RAW264.7 cells and pro-inflammatory cytokines (IL-1ß and IL-6) and matrix metalloproteinase (MMP-8 and MMP-9) in HGF-1 cells. In addition, LAB treatment inhibited osteoclastogenesis by reducing tartrate-resistant acid phosphatase (TRAP) activity and cathepsin K (CtsK) through the downregulation of nuclear factor of activated T cells cytoplasmic 1 (NFATc1) and c-fos gene expression in RANKL-induced RAW264.7 cells. Administration of MG4706 alleviated alveolar bone loss indices and reduced the gene expression of IL-1ß, IL-6, MMP-8, MMP-9, and RANKL/OPG ratio in gingival tissue. In conclusion, L. rhamnosus MG4706 has the potential to alleviate periodontitis.

Maxillary and dental development in the offspring of protein-restricted female rats.

Nutritional restriction during developmental periods impairs organ physiology. Female rats were subjected to protein restriction during pregnancy and lactation to analyze dental and maxillary development. Four exposure groups were considered: normal-protein diet during pregnancy and lactation (NP, 17% casein), low-protein diet during lactation (LP-L, 6% casein), low-protein diet during pregnancy and lactation (LP), and low-protein diet during pregnancy (LP-G). Maxillae from 15-day-old male pups were collected. All protein-restricted groups presented increased dentin thickness and reduced alveolar bone area. When protein restriction was applied during both gestation and lactation (LP), harmful effects were observed in the form of loss of protective OPG (osteoprotegerin) in tooth epithelium-mesenchyme, due to higher RANKL expression, delay in odontoblast maturation, less dental pulp vascularity, reduction in amount of alveolar bone, and less matrix mineralization. In the LP-L group, effects of protein restriction seemed less harmful, and despite less alveolar bone, the enhancement in BMP-7, VEGF, and RANKL seems a compensatory signal to maintain maxillary osteogenesis. In LP-G animals, Dspp expression was higher, suggesting a delay in odontoblast maturation or expression recuperation. In conclusion, maternal protein restriction affects dental and maxillary development. A low-protein diet only in gestation allows for normal development. A low-protein diet during gestation-lactation results in impaired odontogenesis that may increase susceptibility of dental anomalies.

Traditional Chinese Medicine Rhodiola Sachalinensis Borissova from Baekdu Mountain (RsBBM) for Rheumatoid Arthritis: Therapeutic Effect and Underlying Molecular Mechanisms.

The lack of effective rheumatoid arthritis (RA) therapies is a persistent challenge worldwide, prompting researchers to urgently evaluate traditional Chinese medicines (TCMs) as potential clinical RA treatments. The present investigation was conducted to evaluate the therapeutic effects and potential molecular mechanisms of the active components isolated from TCM Rhodiola sachalinensis Borissova from Baekdu Mountain (RsBBM) using an experimental adjuvant arthritis model induced by injection of rats with Freund's complete adjuvant. After induction of the adjuvant arthritis rat model, the extract-treated and untreated groups of arthritic rats were evaluated for RsBBM therapeutic effects based on comparisons of ankle circumferences and ELISA-determined blood serum inflammatory factor levels (TNF-α, IL-1ß, and PGE2). In addition, the joint health of rats was evaluated via microscopic examination of hematoxylin-eosin-stained synovial tissues. Furthermore, to explore whether NF-κB and RANK/RANKL/OPG signaling pathways participated in observed therapeutic effects from a molecular mechanistic viewpoint, mRNA and protein levels related to the expression of nuclear factor kappa-B (NF-κB), osteoprotegerin (OPG), and receptor activator of nuclear factor kappa-Β ligand (RANKL) were analyzed via quantitative RT-PCR and Western blot analysis, respectively. Treatment of arthritic rats with the extract of RsBBM was shown to reduce ankle swelling, reduce blood serum levels of inflammatory factors, and alleviate arthritis-associated synovial inflammation and joint damage. Moreover, an RsBBM 50% ethanol extract treatment inhibited bone destruction by up-regulating OPG-related mRNA and protein expression and down-regulating RANKL-related mRNA and protein expression, while also reducing inflammation by the down-regulating of the NF-κB pathway activity. The results clearly demonstrated that the extract of RsBBM alleviated adjuvant arthritis-associated joint damage by altering activities of inflammation-associated NF-κB and the RANK/RANKL/OPG signaling pathways. Due to its beneficial effects for alleviating adjuvant arthritis, this RsBBM 50% ethanol extract should be further evaluated as a promising new therapeutic TCM treatment for RA.

Assessment of Strategies for Safe Drug Discontinuation and Transition of Denosumab Treatment in PMO-Insights From a Mechanistic PK/PD Model of Bone Turnover.

Denosumab (Dmab) treatment against postmenopausal osteoporosis (PMO) has proven very efficient in increasing bone mineral density (BMD) and reducing the risk of bone fractures. However, concerns have been recently raised regarding safety when drug treatment is discontinued. Mechanistic pharmacokinetic-pharmacodynamic (PK-PD) models are the most sophisticated tools to develop patient specific drug treatments of PMO to restore bone mass. However, only a few PK-PD models have addressed the effect of Dmab drug holidays on changes in BMD. We showed that using a standard bone cell population model (BCPM) of bone remodelling it is not possible to account for the spike in osteoclast numbers observed after Dmab discontinuation. We show that inclusion of a variable osteoclast precursor pool in BCPMs is essential to predict the experimentally observed rapid rise in osteoclast numbers and the associated increases in bone resorption. This new model also showed that Dmab withdrawal leads to a rapid increase of damage in the bone matrix, which in turn decreases the local safety factor for fatigue failure. Our simulation results show that changes in BMD strongly depend on Dmab concentration in the central compartment. Consequently, bone weight (BW) might play an important factor in calculating effective Dmab doses. The currently clinically prescribed constant Dmab dose of 60 mg injected every 6 months is less effective in increasing BMD for patients with high BW (2.5% for 80 kg in contrast to 8% for 60 kg after 6 years of treatment). However, bone loss observed 24 months after Dmab withdrawal is less pronounced in patients with high BW (3.5% for 80kg and 8.5% for 60 kg). Finally, we studied how to safely discontinue Dmab treatment by exploring several transitional and combined drug treatment strategies. Our simulation results indicate that using transitional reduced Dmab doses are not effective in reducing rapid bone loss. However, we identify that use of a bisphosphonate (BP) is highly effective in avoiding rapid bone loss and increase in bone tissue damage compared to abrupt withdrawal of Dmab. Furthermore, the final values of BMD and damage were not sensitive to the time of administration of the BP.