Receptor Activator Of Nuclear Factor kappa-B Ligand Levels Research Articles

Investigation of the preventive effect of methylsulfonylmethane on alveolar bone loss and oxidative stress in a rat model of periodontitis

BackgroundTo investigate the preventive efficacy of methylsulfonylmethane (MSM) on alveolar bone destruction in rats with periodontitis.MethodsTwenty-four male Sprague-Dawley rats were randomly divided into three groups: control, experimental periodontitis (Ep), and Ep-MSM. Periodontitis was induced by placing 4.0 silk sutures in the subparamarginal position on the necks of the mandibular first molars and applying the suture for 5 weeks. The Ep-MSM group was given 500 mg/body weight/day MSM intraperitoneally for 35 days. At the end of the study, bilateral mandibular samples were taken. Periodontal bone loss was measured through histologic sections. Histomorphometric and immunohistochemical (receptor activator of nuclear factor kappa B ligand (RANKL), osteoprotegerin (OPG)) evaluations were performed on right mandibular tissue samples, and biochemical (interleukin (IL)-1 beta (β)/IL-10, malondialdehyde (MDA), glutathione (GSH), oxidative stress index (OSI)) evaluations were performed on left mandibular tissue samples.ResultsNo significant difference was found between the groups in IL-1β and IL-1β/IL-10 values ​​(p > 0.05). A significant decrease in IL-10 levels was observed in the Ep-MSM and Ep groups compared with the control group (p < 0.05). MDA levels significantly increased in the Ep and Ep-MSM groups compared with the control group, and GSH levels significantly decreased in the Ep group compared with the other groups (p < 0.05). OSI values ​​were significantly higher only in the Ep group (p < 0.05). RANKL levels showed a significant increase in the Ep group compared with the other groups. OPG levels were significantly increased only in the Ep-MSM group (p < 0.05).ConclusionsThe results of this study may suggest that MSM has preventive effects on alveolar bone loss and oxidative stress.

Bone resorption marker RANKL in the diagnosis and treatment of patients with maxillary sinus cysts

Background. RANKL (Receptor Activator of Nuclear Factor Kappa-B Ligand) is a protein belonging to the tumor necrosis factor superfamily serving as a specific marker for osteoclast activation and osteolysis. Aim. To determine RANKL levels in the homogenates of Maxillary Sinus Cysts (MSC) at the time of their removal, investigate the correlation of these indicators with the presence of pathology in the upper row of projection teeth in the respective patients, and refine the timing for potential dental implantation or sinus lifting after sinusotomy based on these findings. Materials &amp; Methods. The study included 25 patients aged 20–65 years who underwent surgical treatment for MSCs located on the inferior wall of the sinus. The research methods comprised general clinical, otorhinolaryngological, radiological, and pathohistological techniques and Enzyme-Linked ImmunoSorbent Assay (ELISA) for RANKL in the tissues of the removed cysts. Pathohistological examination revealed retention cysts in 11 patients and pseudocysts in 14 patients. The presence of dental pathology and active odontogenic processes at the time of cyst removal was established based on prospective clinical and radiological evaluations. The dynamics of mucoperiosteal defect regeneration in the MSC, considering RANKL levels, were assessed 3–6 months post-surgery. Results. In the postoperative period, 8 (32%) out of 25 patients exhibited odontogenic alteration processes in the tissues of the maxilla adjacent to the cysts. The RANKL concentration in these patients was [80.65±34.22] pg/µg of protein, while in the other 17 patients without signs of bone damage, it was [33.10±4.35] pg/µg of protein (p&lt;0.05). The threshold RANKL concentration distinguishing these groups in this study was 51.50 pg/µg of protein. Conclusions. In patients with peri-apical bone changes in the maxilla in the projection area of the cysts (alveolar recess), the RANKL level in their homogenates is higher compared to patients without such pathology. Measuring RANKL levels in the homogenates of cysts removed during endonasal maxillary sinusotomy can serve as an additional indicator for planning postoperative dental treatment in these patients. Keywords: ENT-pathology, endoscopic rhinosurgery, histology, postoperative period, paranasal sinus x-ray, treatment.

Vertebral marrow fat fraction is associated with circulating RANKL in postmenopausal females.

To investigate the relationship between circulating receptor activator of nuclear factor-kappa B ligand (RANKL) levels and marrow adipose tissue in postmenopausal females. A total of 164 postmenopausal females were included in the study. Serum levels of osteoprotegerin (OPG) and RANKL were measured using ELISA kits. Body composition and bone mineral density (BMD) were assessed using dual-energy X-ray absorptiometry. Complex-based chemical shift imaging-based MRI was employed to evaluate the vertebral marrow proton density fat fraction (PDFF). A multivariate linear regression model was utilized to analyze the predictive effects of PDFF and BMD on circulating levels of OPG and RANKL. Simple regression analysis showed significant associations among the marrow PDFF, BMD at either site, serum RANKL, and the RANKL/OPG ratio. In multivariate linear regression models, marrow PDFF was found to have a positive correlation (β = 3.15, 95% CI 2.60 to 3.70) and BMD had negative correlations (β = -0.200, 95% CI -0.348 to -0.051 for vertebral BMD; β = -0.383, 95% CI -0.589 to -0.177 for total hip BMD; and β =-0.393, 95% CI -0.598 to -0.188 for femoral neck BMD, all p < 0.01) with circulating soluble RANKL levels after adjusting for age, body mass index, physical activity, total fat mass, android/gynoid ratio, and lean mass. Similar results were observed for the RANKL/OPG ratio. Additionally, multivariate linear regression analyses revealed that marrow PDFF was a significant independent contributor of circulating soluble RANKL (β = 1.34, 95% CI 1.10 to 1.58, p < 0.001) after further controlling for BMD. However, marrow PDFF or BMD had no associations with circulating levels of OPG after adjusting for all potential confounders mentioned above. Vertebral marrow fat fraction is independently associated with circulating soluble RANKL levels in postmenopausal females.

Gingerol nanoparticles attenuate complete Freund adjuvant-induced arthritis in rats via targeting the RANKL/OPG signaling pathway.

Rheumatoid arthritis (RA) is characterized by inflammatory joint pathology leading to the degradation of articular bone and cartilage, primarily triggered by synovial inflammation, resulting in joint discomfort. The metacarpophalangeal and proximal interphalangeal joints are predominantly affected. Treatment typically involves a combination of biological and synthetic disease-modifying antirheumatic drugs (DAMARDs) alongside steroid therapy. The application of nanomedicine has been instrumental in enhancing treatment efficacy by facilitating controlled release of pharmacologically active compounds, thus augmenting bioavailability and enabling targeted drug delivery. Gingerol, a constituent of ginger, possesses multifaceted properties. including anti-inflammatory, anti-oxidant, antidiabetic, and antipyretic effects. In this study, gingerol-loaded poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs), coated with chitosan, were administered orally to rats over a period of 21days to address RA induced by complete Freund adjuvant (CFA). The rats were segregated into four experimental groups. Upon completion of the treatment regimen, blood samples were collected for the assessment of cyclooxygenase-2 (COX-2), RA factor, interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α). Subsequent gene expression analysis was conducted to evaluate the levels of interleukin-4 (IL-4), interleukin-17a (IL-17a), IL-6, interferon-gamma (INF-γ), TNF-α, interleukin-1 beta (IL-1β), osteoprotegerin (OPG), and receptor activator of nuclear factor kappa-B ligand (RANKL). Statistical analyses utilizing one-way ANOVA followed by Tukey tests were applied to the data. The gene expression profiling revealed significant disparities in mRNA levels of IL-1β, IL-6, IL-4, IL-17a, RANKL, INF-γ, and TNF-α between the CFA-induced arthritis group and the control group. Consequently, it was inferred that gingerol-loaded PLGA NPs coated with chitosan exhibited heightened therapeutic efficacy in addressing CFA-induced arthritis in rats.

Lipocalin-2 as a fundamental protein in type 2 diabetes and periodontitis in mice.

Lipocalin-2 (LCN-2) is an osteokine that suppresses appetite, stimulates insulin secretion, regulates bone remodeling, and is induced by proinflammatory cytokines. The aim of this work was to investigate the participation of LCN-2 in periodontitis associated with type 2 diabetes (T2D) by evaluating alveolar bone loss, glycemic control, inflammation, and femur fragility. A murine model of periodontitis with T2D and elevated LCN-2 concentration was used. Functional LCN-2 inhibition was achieved using an anti-LCN-2 polyclonal antibody, and isotype immunoglobulin G was used as a control. The alveolar bone and femur were evaluated by micro-CT. Glucose metabolism was determined. Tumor necrosis factor (TNF-α) and receptor activator of nuclear factor kappa-B ligand (RANKL) levels in alveolar bone lysates were quantified using ELISA, and serum cytokines were quantified using flow cytometry. A three-point bending test was performed in the femur, and RANKL levels were measured in femur lysates using ELISA. Functional inhibition of LCN-2 in T2D-periodontitis mice decreased alveolar bone loss in buccal and palatal surfaces and preserved the microarchitecture of the remaining bone, decreased TNF-α and RANKL in alveolar bone, reduced hyperglycemia, glucose intolerance, and insulin resistance, and increased insulin production through improving the functionality of pancreatic β cells. Furthermore, this inhibition increased serum free-glycerol levels, decreased serum interleukin (IL)-6, increased serum IL-4, and reduced femur fragility and RANKL expression in the femur. LCN-2 participates in periodontitis associated with T2D. Inhibiting its function in mice with T2D and periodontitis improves pancreatic β-cell function, and glucose metabolism and decreases inflammatory cytokines and bone-RANKL levels, which results in the preservation of femoral and alveolar bone microarchitecture. In this study, we explored the role of a bone protein known as lipocalin-2 (LCN-2) in the connection between periodontitis and type 2 diabetes (T2D). Periodontitis is a destructive gum and alveolar bone disease. LCN-2 levels are increased in both T2D and periodontitis. Using a mouse model of T2D with periodontitis, we examined how blocking LCN-2 function affected various aspects of these two diseases. We found that this inhibition led to significant improvements. First, it reduced alveolar bone loss and preserved bone structure by decreasing local inflammation and bone resorption. Second, it improved glucose and lipid metabolism, leading to better blood-sugar control and decreased insulin resistance. Blocking the functions of LCN-2 also decreased systemic inflammation throughout the body and strengthened bone integrity. Overall, our results suggest that LCN-2 plays a crucial role in the periodontitis associated with T2D. By inhibiting LCN-2 function, we were able to improve pancreatic function, improve glucose metabolism, reduce inflammation, and enhance bone health. Targeting LCN-2 could be a promising strategy for the harmful effects of T2D and periodontitis.

Circulating receptor activator of nuclear factor kappa-B ligand (RANKL) levels predict response to immune checkpoint inhibitors in advanced non-small cell lung cancer (NSCLC)

BackgroundReceptor activator of nuclear factor kappa-B ligand (RANKL) can directly promote tumor growth and indirectly support tumor immune evasion by altering the tumor microenvironment and immune cell responses. This study...

Effect of low-intensity laser therapy on levels of biomarkers during orthodontic tooth movement – A systematic review

This systematic review aimed to explore the association between low-intensity laser therapy (LILT) and various biomarkers, elucidating the potential of this therapeutic modality to expedite orthodontic tooth movement (OTM). A systematic literature search was conducted using electronic databases including PubMed, Central of the Cochrane Library, and Google Scholar databases. Randomized controlled trials (RCTs) and non-randomized controlled clinical trials (nRCTs) using LILT as an adjunct to the standard orthodontic procedures in human and animal subjects as participants were included in the study. The quality of the human and animal studies was assessed using the Revised Cochrane risk of bias tool and Systematic Review Centre for Laboratory Animal Experimentation’s (SYRCLE’s) risk of bias tool respectively. Animal studies revealed increased receptor activator of nuclear factor-kappa B (RANK)/RANK ligand (RANKL), matrix metalloproteinase-9 (MMP-9), and collagen type I expression. Human studies showed elevated interleukin-1-beta (IL-1β), interleukin-16 (IL-16) and RANKL levels, suggesting LILT influences biomarkers associated with bone resorption and connective tissue rearrangement. A high risk of bias was observed in all animal studies and 5 out of 6 human studies. The systematic review concluded that LILT emerges as a promising technique for enhancing orthodontic tooth movement, influencing key biomarkers linked to osteoclastic activity and collagen synthesis. However, the high risk of bias in animal and human studies emphasizes the need for further research to validate findings and optimize laser parameters for clinical benefits.

Modulation of the hepatic RANK-RANKL-OPG axis by combined C5 and CD14 inhibition in a long-term polytrauma model.

Polytrauma and hemorrhagic shock can lead to direct and indirect liver damage involving intricate pathophysiologic mechanisms. While hepatic function has been frequently highlighted, there is minimal research on how the receptor activator of the NF-κB (RANK)/RANK ligand (RANKL)/osteoprotegerin (OPG) system is regulated in the liver following trauma. Furthermore, cross-talking complement and toll-like-receptor (TLR) systems can contribute to the posttraumatic response. Therefore, we investigated the hepatic consequences of polytrauma focusing on the RANK-RANKL-OPG axis, and evaluated the effects of a dual blockade of complement factor C5 and TLR-cofactor CD14 on hepatic features. The established pig model of polytrauma (PT) and hemorrhagic shock included pulmonary contusion, hepatic dissection, and bilateral femur fractures, surgically addressed either by external fixation (Fix ex) or intramedullary nailing (Nail). Four groups were investigated: 1) sham animals; 2) PT treated by Fix ex (Fix ex); 3) PT by Nail (Nail); or 4) PT by Nail plus combined C5/CD14 inhibition (Nail+Therapy). Serum samples were obtained between 0 - 72 h, and liver samples at 72 h after PT. Liver tissues were histologically scored and subjected to RT-qPCR-analyses, immunohistochemistry and ELISAs to evaluate the posttraumatic hepatic response with a focus on the RANK-RANKL-OPG system. Following PT, the liver injury score of the Nail+Therapy group was significantly lower than in the Fix ex or Nail group without immunomodulation (p<0.05). Similarly, the degree of necrosis, lobular stasis, and inflammation were significantly reduced when treated with C5/CD14-inhibitors. Compared to the Nail group, AST serum concentrations were significantly decreased in the Nail+Therapy group after 72 h (p<0.05). PCR analyses indicated that RANK, RANKL, and OPG levels in the liver were increased after PT in the Nail group compared to lower levels in the Nail+Therapy group. Furthermore, liver tissue analyses revealed increased RANK protein levels and cellular immunostaining for RANK in the Nail group, both of which were significantly reduced in the case of C5/CD14-inhibition (p<0.05). Following experimental PT, dual inhibition of C5/CD14 resulted in altered, mainly reduced hepatic synthesis of proteins relevant to bone repair. However, a comprehensive investigation of the subsequent effects on the liver-bone axis are needed.

Systemic Melatonin Supplementation as an Adjunct to Non-Surgical Periodontal Treatment in Obese Patients with Periodontitis

Background: Obesity is considered an important risk factor for periodontal disease. It has been reported that reactive oxygen species linking both diseases, systemic melatonin supplementation as antioxidant therapy, was addressed as an adjuvant to scaling and root surface debridement (SRP) to enhance the treatment of periodontitis. Objective: To investigate the efficacy of systemic melatonin administration in periodontitis-obese patients as an adjuvant to scaling and root surface debridement (SRP). Methods: A randomized clinical trial was conducted at a dental-specialized center. Eighty subjects were included and allocated into group-I: twenty periodontium-healthy, normal-weight people; group-II: 30 obese patients with stage-III treated only with SRP; and group-III: 30 obese patients with stage-III periodontitis treated with SRP and 5mg melatonin. periodontitis and subjected to estimation, serum levels of Receptor Activator of Nuclear Factor-Kappa B Ligand (RANKL) were estimated in all groups. Probing pocket depth (PPD), bleeding on probing (BOP), and relative attachment level (RAL) were estimated in Groups II and III at baseline and after a one-month visit. Results: RANKL baseline visits were significantly different between the control and studied groups, with no significant difference in clinical parameters except for PPD. The 2nd visit showed a significant difference in BOP score-1 compared to RAL and BOP score 0. In the second visit, only weak negative and positive significant correlations were found between RANKL and BOP. Conclusion: Daily use of 5 mg of melatonin improves periodontal parameters and decreases serum RANKL levels.

Inflammation is responsible for systemic bone loss in patients with seropositive rheumatoid arthritis treated with rituximab.

We investigated the effect of rituximab on systemic bone metabolism in patients with seropositive rheumatoid arthritis (RA). Twenty seropositive patients with RA were enrolled and administered one cycle of rituximab. If RA became active for > 6 months after the first rituximab cycle, a second cycle was initiated; otherwise, no additional treatment was administered. Patients were divided into two groups according to the number of rituximab treatment cycles. In patients treated with a second cycle, the total hip bone mineral density (BMD) was clinically low, whereas the serum levels of receptor activator of nuclear factor kappa-B ligand (RANKL) were increased at 12 months. BMD in patients treated with one cycle did not change at 12 months, whereas serum RANKL levels decreased at all time points. DAS28 activity improved in both groups from baseline to 4 months; however, from 4 to 12 months, DAS28 activity worsened in the develgroup with the second cycle but remained stable in the group with one cycle. Systemic inflammation, reflected by increased disease activity, may be responsible for the increase in RANKL levels, which causes systemic bone loss in rituximab-treated patients with RA. Although rituximab affects inflammation, it does not seem to alter systemic bone metabolism in RA.

The effect of vitamin D on the early clinical manifestations of menopausal syndrome and the production of cytokines, involved in bone remodeling

Introduction. The problem of early manifestations of menopausal syndrome is due to the high prevalence among postmenopausal women, a wide range of clinical manifestations, a sharp decrease in the quality of life, not always sufficient effectiveness of menopausal hormone therapy (MHT) in the presence of restrictions on its use.The aim. To evaluate the dynamics of clinical manifestations of menopausal syndrome and to determine the pathogenetic effects of vitamin D preparation when used in combination with menopausal hormone therapy in women of early postmenopausal age with menopausal syndrome.Materials and methods. 154 women were examined, of which 81 were characterized by the presence of clinical manifestations of menopausal syndrome. All women with menopausal syndrome received menopausal hormone therapy with estradiol and didrogesterone drug for 6 months, while 39 women additionally also took the vitamin D drug. Before and after therapy in patients with menopausal syndrome, the prevalence of symptoms of the Green scale was assessed. Concentrations of 25(OH) D, osteoprotegerin (OPG) and receptor activator of nuclear factor kappa-B ligand (RANKL) were determined in the blood serum of all women.Results and discussion. The use of MHT by women with menopausal syndrome leads to a decrease in the frequency of registration of a number of symptoms of the Green scale (p &lt; 0.05). At the same time, a decrease in the frequency of registration of individual complaints is found only in the group of women who, along with MYT, received a vitamin D preparation (p &lt; 0.05). Taking the vitamin D preparation is accompanied by an increase in its initially reduced serum concentrations to normal values (p &lt; 0.001). The addition of cholecalciferol to the complex therapy of menopausal syndrome ensures the normalization of RANKL levels by reducing its production in the dynamics of treatment (p &lt; 0.05) A decrease in the concentration of RANKL in response to the complex intake of a hormonal drug and cholecalciferol caused higher OPG/RANKL index values in the basic group by the end of therapy than in women of the comparison group (p &lt; 0.01).Conclusions. The obtained effects of vitamin D preparation when prescribed in combination with menopausal hormone therapy (reduction of the frequency of symptoms of menopausal syndrome, reduction of initially elevated levels of RANKL) indicate the expediency of its use in the treatment of early manifestations of menopausal syndrome.

The role of miR-433-3p in vascular calcification in type 2 diabetic patients: targeting WNT/β-Catenin and RANKL/RANK/OPG signaling pathways

BackgroundVascular calcification (VC) is a major predictor of cardiovascular diseases that represent the principal cause of mortality among type-2 diabetic patients. Accumulating data suggest the vital role of some microRNAs on vascular calcification as an epigenetic regulator. Thus, we assessed herein, the role of serum miR-433-3p in vascular calcification in type-2 diabetic patients.MethodsTwenty healthy subjects (control group) and forty diabetic patients (20 without VC and 20 with VC) were involved in the study. miR-433-3p gene expression was measured. Runx2, Dickkopf-1 (DKK1), β-catenin, Receptor activator of nuclear factor kappa-B ligand (RANKL), and osteoprotegerin (OPG) levels in serum were assessed by ELISA technique.ResultsDiabetes patients had significantly lower levels of miR-433-3p expression in comparison to the control group, with the lowest levels being found in diabetic patients with VC. Furthermore, Runx2, β-catenin, and RANKL levels were significantly increased with concomitant lower DKK1 and OPG levels detected in the two diabetic groups especially those with VC.ConclusionCollectively, the study documented that down-regulation of miR-433-3p may contribute to the development of VC through activating WNT/β-Catenin and RANKL/RANK/OPG signaling pathways.

Interleukin-21 knockout reduces bone loss in ovariectomized mice by inhibiting osteoclastogenesis.

Estrogen deficiency accelerates osteoporosis in elderly women. However, the role of IL-21 in postmenopausal osteoporosis remains unclear. Female wild-type (WT) C57BL/6 and IL-21 knockout (KO) mice were used for ovariectomy (OVX). Here, IL-21 levels were significantly increased in the serum and bone tissues of WT-OVX mice. The trabecular bone space of the femur was significantly increased, and the bone mass was reduced in OVX mice, accompanied by a significant decrease in the maximum load, energy absorption, and elastic modulus indices. In contrast, IL-21 knockout effectively alleviated the effects of OVX on bone mass. Serum TRACP-5b and receptor activator of nuclear factor kappa B ligand (RANKL) levels and osteoclastogenesis were significantly higher in OVX mice than in sham mice, while serum TRACP-5b and RANKL levels and osteoclastogenesis were significantly decreased in IL-21 KO+OVX mice compared to WT+OVX mice. IL-21 knockdown reduces TRACP-5b, RANKL, and osteoclastogenesis, effectively preventing bone resorption and alleviating the progression of OVX-induced osteoporosis.

Cystic fibrosis related bone disease in children: Can it be predicted?

Cystic fibrosis (CF) -related bone disease (CFBD) is an important complication of CF, and low BMD in childhood is a precursor of CFBD. Here, we aimed to investigate bone turnover biomarkers, including osteocalcin (OC), receptor activator of nuclear factor kappa B ligand (RANKL) and osteoprotegerin (OPG) in relation to low BMD in children with CF (cwCF). We also evaluated factors which could affect bone turnover with particular emphasis on fat-free mass (FFM), forced expiratory volume in 1s (FEV1), hand grip strength (HGS), and functional capacity and physical activity. Sixteen cwCF aged 8-18 years with moderate low BMD (group1) and 64 cwCF with normal BMD (group2) were enrolled. Serum RANKL, OC, and OPG were determined by immunoenzymatic assays. Multiple parameters including pancreatic status, lung functions, body mass index (BMI), FFM measured by bioelectric impedance analysis (BIA), 6-minute walk test, vitamin D, nutritional intake, HGS, functional capacity and physical activity, serum and urine biomarkers were compared between the two groups. We found similar serum levels of RANKL (p=0.501), OC (p=0.445), OPG (p=0.380), and RANKL/OPG ratio (p=0.449) between group1 and group2 in cwCF. BMI z-score (p<0.001), FFMI z-score (p<0.001), FEV1 z-score (p=0.007), and right-HGS (%pred) (p=0.009) significantly differed between the two groups. Multivariate linear regression revealed that the only factors that predicted BMD were FFMI z-score and HGS %pred. Serum OC, OPG, RANKL and RANKL/OPG ratio did not predict BMD in cwCF. FFMI z-score and HGS %pred measured by non-invasive and practical methods were the best predictors of BMD.

Pro- and anti-inflammatory cytokines and osteoclastogenesis-related factors in peri-implant diseases: systematic review and meta-analysis

BackgroundPro- and anti-inflammatory cytokines are acknowledged, during inflammatory bone destruction, as key regulators of osteoclast and osteoblast differentiation and activity. However, evidence regarding the exact role of pro- and anti-inflammatory cytokines and osteoclastogenesis-related factors in peri-implant diseases is unclear. We aimed to execute a systematic review and meta-analysis about the pro- and anti-inflammatory cytokines and osteoclastogenesis-related factors levels in peri-implant diseases.MethodsThe focused question was elaborated to summarize the levels of pro-and anti-inflammatory cytokines and osteoclastogenesis-related factors in tissue samples (mRNA) and biofluids (protein levels) of patients with/without peri-implant diseases. Electronic searches of the PubMed, Cochrane Controlled Trials Registry, Web of Science, EMBASE, Scopus and Google scholar databases were conducted for publications up to March 2023. Meta-analysis evaluating the mediator´s levels (protein levels by ELISA) in peri-implant crevicular fluid (PICF) were made. The effect size was estimated and reported as the mean difference. The 95% confidence interval was estimated for each mediator, and the pooled effect was determined significant if two-sided p-values < 0.05 were obtained.ResultsTwenty-two publications were included in the systematic review (qualitative analysis), with nine of these subjected to meta-analyses (quantitative analysis). In the qualitative analysis, higher pro-inflammatory cytokines [Interleukin (IL)-1β, IL-6] and pro-osteoclastogenic mediator [Receptor Activator of Nuclear Factor-Kappa B ligand (RANKL)] levels were observed in PICF of individuals with peri-implant diseases in comparison to healthy individuals. Higher RANKL/osteoprotegerin (OPG) ratios were observed in PICF from individuals with peri-implant diseases in comparison to healthy individuals. Meta-analysis showed higher RANKL levels in diseased groups compared to controls.ConclusionsThe results showed that the levels of IL-1β, IL-6, IL-10, and RANKL/OPG are not balanced in peri-implant disease, suggesting that these mediators are involved in the host osteo-immunoinflammatory response related to peri-implantitis.

Comparative study of the synovial levels of RANKL and OPG in rheumatoid arthritis, spondyloarthritis and osteoarthritis

IntroductionIn chronic arthropathies, there are several mechanisms of joint destruction. In recent years, studies have reported the implication of receptor activator of nuclear factor kappa-B ligand (RANKL) and osteoprotegerin (OPG) in the process of activation and differentiation of osteoclasts, a key cell in the development of bone erosion. The RANKL/OPG ratio is increased in the serum of patients with malignant diseases and lytic bone disease, as well as rheumatoid arthritis (RA). The objective of this study was to measure and compare the concentrations of OPG and RANKL in the synovial fluid (SF) of patients with rheumatoid arthritis, spondyloarthritis (SpA) and osteoarthritis (OA).MethodsThis was an observational and cross-sectional study with 83 patients, 33 with RA, 32 with SpA and 18 with OA, followed up regularly in the outpatient clinics of the Rheumatology Department of the Clinics Hospital of the Ribeirão Preto Medical School-USP. All patients were assessed for indications for arthrocentesis by the attending physicians at the time of SF collection and were evaluated for demographic variables and medication use. Disease activity was assessed in individuals with RA and SpA. The quantification of SF OPG and RANKL levels was performed by ELISA, and the correlations of the results with clinical, laboratory and radiological parameters were assessed.ResultsWe found no statistically significant difference in the RANKL and OPG levels among the groups. Patients with RA showed a positive correlation between the SF cell count and RANKL level (r = 0.59; p < 0.05) and the RANKL/OPG ratio (r = 0.55; p < 0.05). Patients with OA showed a strong correlation between C-reactive protein (CRP) and the RANKL/OPG ratio (r = 0.82; p < 0.05). There was no correlation between the OPG and RANKL levels and markers of inflammatory activity or the disease activity index in patients with RA or SpA.ConclusionWithin this patient cohort, the RANKL/OPG ratio was correlated with the SF cell count in patients with RA and with serum CRP in patients with OA, which may suggest a relationship with active inflammation and more destructive joint disease.

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.

Role of denosumab in bone erosions in rheumatoid arthritis.

Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by systemic inflammation and synovitis which evolve into joint destruction and deformity. Bone abnormalities are represented by marginal bone erosions and iuxta-articular and generalized osteoporosis. Overactivation of osteoclasts along with dysregulation of osteoblasts are the key events. Bone resorption is mediated by the receptor activator of nuclear factor (NF)-κB (RANK) ligand (RANK-L), responsible for the differentiation, proliferation, and activation of osteoclasts. RANK-L binds its receptor RANK, localized on the surface of preosteoclasts and mature osteoclasts promoting osteoclastogenesis. High levels of RANK-L were demonstrated in active RA patients. Denosumab, a fully human monoclonal antibody, binds RANK-L and suppresses the RANK-RANK-L signaling pathway leading to the inhibition of osteoclastogenesis. A retrospective analysis of published studies such as clinical trials evidenced the efficacy of denosumab in preventing bone erosion progression in RA patients. Key messages Key questions to answer in future include the following: Could denosumab be associated with other biologic therapies in RA patients? Could denosumab block the progression of bone damage in RA? Could denosumab be used for the prevention of bone erosion in RA?

Serum OPG and RANKL Levels as Risk Factors for the Development of Cardiovascular Calcifications in End-Stage Renal Disease Patients in Hemodialysis

Cardiovascular calcifications (CVC) are frequently observed in chronic kidney disease (CKD) patients and contribute to their cardiovascular mortality. The aim of the present study was to investigate the impact of osteoprotegerin (OPG)/Receptor Activator of NF-κΒ (RANK)/RANK ligand (RANKL) pathway in the development and evolution of CVCs in hemodialysis patients. In total, 80 hemodialysis patients were assessed for the presence of vascular (abdominal aorta and muscular arteries) calcifications and results were correlated to serum OPG and RANKL levels and the OPG/RANKL ratio. Traditional cardiovascular risk factors and mineral bone disease parameters were also estimated. The presence of VCs was also evaluated 5 years after the initiation of the study, and results were correlated to the initial serum OPG levels. Age, diabetes mellitus, coronary artery disease and OPG levels (p < 0.001) were associated with VCs, whereas RANKL levels were not. Multivariate analysis though revealed that only OPG levels were significantly associated with abdominal aorta calcifications (p = 0.026), but they were not correlated with the progression of VCs. Serum OPG levels are positively and independently associated with VCs in HD patients, but not with their progression. RANKL levels did not show any associations, whereas further studies are needed to establish the significance of OPG/RANKL ratio.

Changes in RANKL and TRAcP 5b after discontinuation of denosumab suggest RANKL mediated formation of osteoclasts results in the increased bone resorption

The rapid increase in bone turnover occurring when discontinuing long-term treatment with denosumab (DMAB), an antibody that neutralizes receptor activator of nuclear factor kappa-B ligand (RANKL) is not fully understood. We aimed to investigate the mechanisms underlying the rebound activation of bone resorption by measuring tartrate-resistant acid phosphatase 5b (TRAcP 5b), RANKL, osteoprotegerin (OPG), C-terminal collagen crosslinks (CTX), and procollagen type I N-propeptide (P1NP) in patients discontinuing long-term DMAB. Sixty-one patients with BMD T-score > - 2.5 at the spine and hip discontinuing long-term DMAB were randomized to treatment with zoledronate (ZOL) 6months (6M group, n = 20), 9months (9M group, n = 20) or 12months after the last DMAB injection or when bone turnover was high (12M group, n = 21). Bone turnover markers were measured immediately before initiation of ZOL treatment. We found higher CTX and PINP in the 9M and 12M groups compared to the 6M group (p < 0.001). In the 6M group, TRAcP 5b was lower and RANKL higher than in the other two groups (p < 0.001). TRAcP 5b correlated negatively with RANKL (R = - 0.54), and time since the last DMAB injection correlated positively with CTX (R = 0.56), PINP (R = 0.72), TRAcP 5b (R = 0.51) and negatively with RANKL (R = - 0.70) (p < 0.001 for all). We found no difference in OPG between groups. Following discontinuation of long-term DMAB, we find high levels of RANKL, which most likely result in an increase in the number of active osteoclasts (illustrated by TRAcP5b) causing an increased bone turnover.