Plasma Levels Of RANKL Research Articles

Circulating mRNA and plasma levels of osteoprotegerin and receptor activator of NF-κB ligand in nonalcoholic fatty liver disease.

Pathogenesis of the beginning and progression of nonalcoholic fatty liver disease (NAFLD) has not been clarified exactly. The osteoprotegerin (OPG)/receptor activator of NF-κB ligand (RANKL) axis seems to play an imperative function in the onset and progression of this disease. The goal of the present study was to investigate the peripheral blood mononuclear cell (PBMC) expression and plasma levels of RANKL and OPG cytokines in NAFLD patients and compare them with healthy group. Plasma levels of OPG and RANKL were determined with ELISA kits in 57 men with NAFLD and 25 healthy men as controls. Biochemical and anthropometric parameters tests were also evaluated in the study groups. RANKL and OPG mRNA contents were evaluated by quantitative RT-PCR. OPG contents were markedly decreased in NAFLD patients as compared with healthy patients [1.43 (1.05-5.45)] versus [2.94 (1.76-4.73)] ng/mL; P=0.007). The levels of RANKL were significantly reduced in NAFLD patients [74.00 (56.26-203.52) ng/mL] than in healthy patients [119.37 (83.71-150.13) ng/mL]; (P=0.03). Also, OPG and RANKL gene expression were significantly decreased in NAFLD patients in comparison with the control group (P<0.05). Moreover, receiver operating characteristic curve indicated that OPG may have a good capability to discriminate between NAFLD patients and normal individuals. A positive correlation was observed between OPG and RANKL in plasma sample (r=0.495) (P=0.000). Decreased plasma levels and gene expression of RANKL and OPG cytokines in NAFLD patients indicate that there is a relationship between these cytokines and the pathology of NAFLD disease. Confirmation of this association as well as the mechanism and role of these cytokines in NAFLD require further studies.

Osteoclastic activity was associated with the development of steroid-induced osteonecrosis of femoral head

This study is focussed on evaluating and comparing two mediators of osteoclast, osteoprotegerin (OPG) and nuclear factor-κB ligand (RANKL), in plasma and tissue levels in patients with steroid-induced osteonecrosis of femoral head (SIONFH). Subjects were included in this cross-sectional case-control study in 2016. Bone histomorphology, immunohistochemistry, Western blotting, OPG and RANKL plasma levels, post-hoc statistical power and receiver-operating characteristic (ROC) curves were evaluated. Eighty-six patients diagnosed with SIONFH and 51 healthy subjects were included. OPG expression levels in bone samples increased with ARCO stage, and RANKL expression levels decreased with ARCO stages. Plasma OPG and RANKL levels were significantly higher in the SIONFH group compared with the healthy control group. The plasma OPG level and ratio of OPG and RANKL were positively associated with ARCO stages and significantly higher in stages III and IV. Plasma RANKL levels were negatively associated with ARCO stage and were significantly higher in ARCO stages II and III. Plasma OPG and RANKL may represent potential biomarkers during SIONFH at different stages. Higher plasma OPG levels indicated late-stage SIONFH, and higher plasma RANKL levels indicated early stage. Our findings may provide a clue for the development of diagnostic tools and therapies for SIONFH.

Plasma RANKL levels are not associated with breast cancer risk in BRCA1 and BRCA2 mutation carriers.

BackgroundAberrant progesterone/receptor activator of nuclear factor κβ (RANK) signaling has been implicated in BRCA1 breast cancer development. Furthermore, lower circulating RANKL has been reported among women with a BRCA mutation compared to non-carriers; however, there have been no reports of plasma RANKL levels and subsequent breast cancer risk. We prospectively evaluated the relationship between plasma RANKL and breast cancer risk among women with a BRCA1 or BRCA2 mutation.MethodsAn enzyme-linked immunosorbent assay was used to quantify plasma RANKL levels in 184 BRCA mutation carriers. Women were stratified into high vs. low RANKL based on the median levels of the cohort (5.24 pg/ml). Kaplan-Meier survival analysis was used to estimate the cumulative incidence of breast cancer by baseline plasma RANKL and cox proportional hazards models were used to estimate the adjusted hazard ratios (HRs) and 95% confidence intervals (CI) for the association between plasma RANKL and risk.ResultsOver a mean follow-up of 6.3 years (0.02-19.24), 15 incident breast cancers were identified. The eight-year cumulative incidence was 10% in the low RANKL group and 12% in the high RANKL group (P-log-rank = 0.85). There was no significant association between plasma RANKL levels and breast cancer risk (multivariate HR high vs. low = 1.06; 95%CI 0.34-3.28; P-trend = 0.86).ConclusionsThese findings suggest that circulating RANKL levels are not associated with breast cancer among BRCA mutation carriers. Pending validation in a larger sample, these findings suggest that RANKL is likely not a biomarker of breast cancer risk among BRCA mutation carriers.

Serum levels of RANKL and OPG, and the RANKL/OPG ratio in bisphosphonate-related osteonecrosis of the jaw: Are they useful biomarkers for the advanced stages of osteonecrosis?

BackgroundWe determined whether serum levels of Receptor Activator for Nuclear Factor κ B Ligand (RANKL), Osteoprotegerin (OPG), and the RANKL/OPG ratio could be useful biomarkers for the severity of oral lesions in bisphosphonate-related osteonecrosis of the jaw (BRONJ).Material and MethodsA case-control study in which Group 1 consisted of 41 patients with BRONJ due to intravenous bisphosphonates, and Group 2 consisted of 44 healthy control cases. The plasma levels of RANKL and OPG were analyzed by an ELISA assay. The OPG/RANKL ratio was also calculated. We determined if the mean serum values differed among the different stages of BRONJ. ResultsSerum levels of RANKL were lower in Group 1 than in Group 2 (p =0.01), and serum levels of OPG were higher in patients with BRONJ than in the controls (p =0.006). The ratio of RANKL/OPG was greater in the controls than in Group 1 (P >0.01). There were no significant differences in the serum levels of RANKL and OPG among the different stages of osteonecrosis (P > 0.05).ConclusionsSerum levels of RANKL and OPG, and the RANKL/OPG ratio were not valuable biomarkers for determining the severity of oral lesions in patients with BRONJ. Key words:Bisphosphonates, RANKL, OPG, Osteonecrosis.

Cytocompatibility and biocompatibility of nanostructured carbonated hydroxyapatite spheres for bone repair

ABSTRACTObjective The aim of this study was to investigate the in vitro and in vivo biological responses to nanostructured carbonated hydroxyapatite/calcium alginate (CHA) microspheres used for alveolar bone repair, compared to sintered hydroxyapatite (HA).Material and Methods The maxillary central incisors of 45 Wistar rats were extracted, and the dental sockets were filled with HA, CHA, and blood clot (control group) (n=5/period/group). After 7, 21 and 42 days, the samples of bone with the biomaterials were obtained for histological and histomorphometric analysis, and the plasma levels of RANKL and OPG were determined via immunoassay. Statistical analysis was performed by Two-Way ANOVA with post-hoc Tukey test at 95% level of significance.Results The CHA and HA microspheres were cytocompatible with both human and murine cells on an in vitro assay. Histological analysis showed the time-dependent increase of newly formed bone in control group characterized by an intense osteoblast activity. In HA and CHA groups, the presence of a slight granulation reaction around the spheres was observed after seven days, which was reduced by the 42nd day. A considerable amount of newly formed bone was observed surrounding the CHA spheres and the biomaterials particles at 42-day time point compared with HA. Histomorphometric analysis showed a significant increase of newly formed bone in CHA group compared with HA after 21 and 42 days from surgery, moreover, CHA showed almost 2-fold greater biosorption than HA at 42 days (two-way ANOVA, p<0.05) indicating greater biosorption. An increase in the RANKL/OPG ratio was observed in the CHA group on the 7th day.Conclusion CHA spheres were osteoconductive and presented earlier biosorption, inducing early increases in the levels of proteins involved in resorption.

Effect of Nicotine on RANKL and OPG and Bone Mineral Density

ABSTRACTAim: The signaling pathway OPG/RANK/RANKL is a key in maintaining the balance between the activity of osteoblasts and osteoclasts in order to prevent bone loss. In this study, our aim was to assess the effects of long-term nicotine exposure on plasma RANKL and OPG levels, tissue RANKL and OPG immunoreactivities, and bone mineral density (BMD) scores in rats. Materials and Methods: Thirty-six Swiss Albino rats weighing 70 ± 10 g were divided into three groups. While the controls (n = 12) were only given normal drinking water, for low-dose nicotine (LDN) group (n = 12) 0.4 mg/kg/day; for high-dose nicotine (HDN) group (n = 12), 6.0 mg/kg/day nicotine was added to drinking water for a year. At the end of 12th month, BMD scores were measured using an X-ray absorptiometry and bone turnover was assessed by measuring plasma RANKL and OPG levels and RANKL and OPG immunoreactivities in tail vertebrae of the rats. Results: There was no statistically significant difference in BMD scores of lumbar spine and femoral regions of the nicotine groups in comparison to controls. Plasma OPG levels were found to be significantly higher in HDN group, in comparison to the controls and LDN groups (p = .001) unlike plasma RANKL levels. Tissue RANKL and OPG immunoreactivities decreased significantly in the LDN and HDN groups (p < .001, p < .01, respectively). Conclusions: The results of this study show that nicotine is not primarily responsible for the decrease in BMD frequently seen in smokers. Measuring plasma RANKL and OPG levels did not reflect tissue immunoreactivities.

Elevated Levels of the Mediator of Catabolic Bone Remodeling RANKL in the Bone Marrow Environment Link Chronic Heart Failure with Osteoporosis

Chronic heart failure (CHF) is associated with a 4-fold increased risk for osteoporotic fractures. Therefore, we sought to identify the pathophysiological link between chronic heart failure and catabolic bone remodeling. In a total cohort of 153 subjects (123 patients with CHF, 30 patients with coronary artery disease and preserved cardiac function) as well as mice with heart failure, bone marrow (BM) plasma levels of the catabolic receptor activator of NF-κB ligand (RANKL), and its antagonist, osteoprotegerin were measured. The osteoclast inducing activity of BM plasma was tested in cell culture. BM plasma levels of RANKL and of the ratio RANKL/osteoprotegerin were significantly elevated in patients with CHF. On multivariate regression analysis, parameters of severity and duration of heart failure were independent determinants of elevated BM plasma RANKL levels. BM plasma levels of RANKL were directly correlated with the systemic marker of bone turnover C-telopeptide of type 1 collagen (r=0.6; P<0.001). Alterations in BM plasma levels of RANKL/osteoprotegerin were confirmed in a mouse model of postinfarction heart failure. Stimulation of human mesenchymal cells with BM plasma obtained from CHF patients increased the formation of osteoclasts, and this effect was blocked by the RANKL inhibition. CHF is associated with a profound and selective elevation of the bone resorption stimulating RANKL within the BM microenvironment. These data for the first time disclose a direct pathophysiological pathway linking CHF with catabolic bone remodeling associated with an increased osteoporotic fracture risk. URL: http://www.clinicaltrials.gov. Unique identifiers: NCT 00289822, NCT 00284713, NCT 00326989, NCT 00962364.

A functional RANKL polymorphism associated with younger age at onset of rheumatoid arthritis

We previously observed the association of the co-occurrence of the HLA-DRB1 shared epitope (SE) and RANKL single-nucleotide polymorphisms (SNPs) with younger age at the onset of rheumatoid arthritis (RA) in 182 rheumatoid factor (RF)-positive European American patients with early-onset RA. The aim of this study was to fine-map the 48-kb RANKL region in the extended cohort of 210 European American RF-positive patients with early RA, to seek replication of RA-associated SNPs in additional RA cohorts of 501 European Americans and 298 African Americans, and to explore the functional consequences of RA-associated SNPs. SNP genotyping was conducted using pyrosequencing or TaqMan polymerase chain reaction (PCR) assays. Associations of rs7984870 with RANKL expression in plasma, peripheral blood mononuclear cells, and isolated T cells were quantified using enzyme-linked immunosorbent assay and reverse transcription-PCR. Site-directed mutagenesis of rs7984870 within the 2-kb RANKL promoter was performed to drive the luciferase reporter gene in osteoblast and stromal cell lines. Interaction of DNA and protein was determined by electrophoretic mobility shift assay. A single promoter SNP, rs7984870, was consistently significantly associated with earlier age at the onset of RA in 3 independent seropositive (RF or anti-cyclic citrullinated peptide antibody) RA cohorts but not in seronegative RA patients. The C risk allele of rs7984870 conferred 2-fold higher plasma RANKL levels in RF-positive patients with RA, significantly elevated RANKL messenger RNA expression in activated normal T cells, and increased promoter activity after stimulation in vitro via differential binding to the transcription factor SOX5. The RANKL promoter allele that increased transcription levels upon stimulation might promote interaction between activated T cells and dendritic cells, predisposing to a younger age at the onset of RA in seropositive European American and African American patients.