RANKL and OPG mRNA Level after Non-Surgical Periodontal Treatment

The roles of lncRNAs and miRNAs in pancreatic cancer: a focus on cancer development and progression and their roles as potential biomarkers

Pancreatic ductal adenocarcinoma (PDAC) is among the most penetrative malignancies affecting humans, with mounting incidence prevalence worldwide. This cancer is usually not diagnosed in the early stages. There is also no effective therapy against PDAC, and most patients have chemo-resistance. The combination of these factors causes PDAC to have a poor prognosis, and often patients do not live longer than six months. Because of the failure of conventional therapies, the identification of key biomarkers is crucial in the early diagnosis, treatment, and prognosis of pancreatic cancer. 65% of the human genome encodes ncRNAs. There are different types of ncRNAs that are classified based on their sequence lengths and functions. They play a vital role in replication, transcription, translation, and epigenetic regulation. They also participate in some cellular processes, such as proliferation, differentiation, metabolism, and apoptosis. The roles of ncRNAs as tumor suppressors or oncogenes in the growth of tumors in a variety of tissues, including the pancreas, have been demonstrated in several studies. This study discusses the key roles of some lncRNAs and miRNAs in the growth and advancement of pancreatic carcinoma. Because they are involved not only in the premature identification, chemo-resistance and prognostication, also their roles as potential biomarkers for better management of PDAC patients.

Analysis of Salivary Levels of IL-1β, IL17A, OPG and RANK-L in Periodontitis Using the 2017 Classification of Periodontal Diseases-An Exploratory Observational Study

Periodontitis is a chronic disease with a high overall prevalence. It involves a complex interplay between the immune-inflammatory pathways and biofilm changes, leading to periodontal attachment loss. The aims of this study were (i) to assess whether the salivary IL-1β, IL-17A, RANK-L and OPG levels have the potential to discriminate between the mild and severe periodontitis conditions; and (ii) to enable diagnostic/prognostic actions to differentiate between distinct levels of the disease. The analysis of the clinical parameters and the evaluation of the salivary immunomediators levels by means of a multiplex flow assay revealed a statistically significantly higher level of IL-1β in the periodontitis III/IV patients, as well as a higher level of RANK-L in the periodontitis III/IV and I/II patients, when compared to the healthy controls. Furthermore, the grade C periodontitis patients presented a significantly higher level of RANK-L compared to the grade B and grade A patients. In the grade C patients, IL-1β had a positive correlation with the PPD and CAL indices and RANK_L had a positive correlation with CAL. The evidence emerging from this study associates the salivary IL-1β and RANK-L levels with an advanced stage of periodontitis, stage III/IV, and with grade C, suggesting the possible cooperative action of both in the inflammatory and bone loss events. In addition to IL-1β, RANK-L could be considered a combined diagnostic biomarker for periodontitis.

The expression levels of MicroRNA-146a, RANKL and OPG after non-surgical periodontal treatment

Objective

MicroRNA-146a (miR-146a) is a regulator of inflammatory response. Periodontitis is a disease with immune pathophysiology of the periodontium in which the inflammation results in the destruction of the soft tissues and alveolar bone. Therefore, the aim of this study was to investigate the expressions of miR-146a, OPG, and RANKL in diseased and healthy periodontal tissues to understand whether miR-146a expression level may associate with OPG and RANKL mRNA levels and OPG/RANKL ratio after non-surgical periodontal treatment.

Methods

The levels of miR-146a, RANKL, and OPG in gingival tissues from patients with generalized periodontitis stages II and III and grades A and B (n = 15, group A), patients with generalized periodontitis stages III and IV and grade C (n = 15, group B), and healthy individuals (n = 10) were determined by real-time PCR. The associations of miR-146a expression with OPG and RANKL levels were evaluated.

Results

The levels of miR-146a in two subgroups within periodontitis patients were significantly higher than healthy subjects (P < 0.0001). MiR-146a showed the increased level in group A of patients compared with group B (P < 0.05). Clinical parameters such as probing depth (PD) and clinical attachment loss (CAL) were significantly higher in patients than control group (P < 0.05). The levels of OPG and RANKL were increased in patients compared with healthy subjects, although the elevated levels were not statistically significant. MiR-146a was not associated with OPG and RANKL levels and OPG/RANKL ratio.

Conclusions

The results of this study failed to show the associations of miR-146a level with OPG and RANKL levels and OPG/RANKL ratio in periodontitis after non-surgical periodontal treatment.

Hexokinase 2-mediated glycolysis promotes receptor activator of NF-κB ligand expression in Porphyromonas gingivalis lipopolysaccharide-treated osteoblasts

BACKGROUND

Glucose metabolism plays a pivotal role in sustaining the inflammatory response to microbial stimulation by providing sufficient energy in immune cells. The main purpose of our study was to explore whether hexokinase 2 (HK2)-mediated glycolysis affected the expression of receptor activator of NF-κB Ligand (RANKL) in Porphyromonas gingivalis lipopolysaccharide (P. gingivalis-LPS)-treated osteoblasts and evaluate the potential involvement of the AKT/PI3K pathway activation during HK2-mediated glycolysis.

METHODS

Primary mice osteoblasts were treated with P. gingivalis-LPS, whereas the HK2 inhibitor (Lonidamine, LND) and small interference RNA were used to restrain HK2 expression. Conditioned medium from osteoblasts was utilized for culturing osteoclast precursors. The mRNA and protein levels of genes involved in glycolysis and bone metabolism including RANKL and osteoprotegerin (OPG) were detected by real-time PCR and western blotting. HK2 and lactate levels were detected by ELISA. Tartrate-resistant acid phosphatase (TRAP) staining was utilized to assess osteoclast formation. The involvement of the AKT/PI3K pathway in osteoblasts was explored by Western blotting.

RESULTS

P. gingivalis-LPS enhanced HK2 expression along with rising glycolysis in osteoblasts. LND and HK2-knockdown decreased RANKL expression and the RANKL/OPG ratio in osteoblasts, leading to less osteoclast formation from osteoclast precursors as evidenced by TRAP staining, while the osteogenic potential and proliferation of osteoblasts were not affected by HK2-knockdown. Moreover, P. gingivalis-LPS activated the AKT/PI3K pathway, which could regulate HK2 and RANKL expression in osteoblasts.

CONCLUSIONS

HK2-mediated glycolysis promoted RANKL in osteoblasts and enhanced osteoclast differentiation. Targeting glycolysis may provide novel therapeutic methods for reducing alveolar bone loss.

AdipoRon Promotes the Osseointegration of Dental Implants in Mice With Type 2 Diabetes Mellitus

AdipoRon is an oral active synthetic small molecule with biological functions similar to adiponectin (APN). It is an APN receptor agonist that can improve insulin resistance and glucose intolerance. However, the role of AdipoRon in bone metabolism and related molecular mechanisms remains to be investigated. To explore the effect of AdipoRon on bone absorption and bone integration of type 2 diabetes mellitus (T2DM) mice with implants, we established surgery-induced model of osseointegration of dental implantation in T2DM mice of C57BL/6 db/db and normal mice homologous to diabetic mice. Micro-CT was used to analyze the femurs with the implant in the mice to detect the bone mass, H&E, and tartrate-resistant acid phosphatase (TRAP), and Safranin O-fast green staining was performed to analyze the bone formation and bone resorption. Bone integration-related markers as Rankl, bone morphogenetic protein 2 (BMP2), osteoprotegerin (OPG), osteopontin (OPN), and runt-related transcription factor 2 (Runx2) were also measured using immunohistochemistry. Our results indicated that diabetic mice showed a lower bone mass and decreased the osteoblast differentiation. AdipoRon attenuated diabetes-impaired bone volume (BV)/total volume (TV), trabecular thickness (Tb.Th), trabecular number (Tb.N), trabecular separation (Tb.Sp), and bone integration-related markers variation and promoted bone hyperplasia as well as repressed the osteoclast formation, especially in diabetic mice. AdipoRon may improve the osseointegration of dental implants in mice with T2DM by promoting osteogenesis and inhibiting bone resorption, and AdipoRon may serve as a promising oral strategy to improve the osseointegration ability of patients with diabetes.

Emerging roles of Interleukin-34 together with receptor activator of nuclear factor-kB ligand and osteoprotegerin levels in periodontal disease

OBJECTIVE

The dependence between gingival crevicular fluid (GCF) of Interleukin-34 (IL-34) level and Receptor activator of nuclear factor -kB ligand/ osteoprotegerin (RANKL/OPG) ratio in the severity of periodontitis might reveal an unknown pathway of diseases with bone destruction. There is no study about the evaluation of IL-34 levels together with GCF RANKL and OPG levels in periodontitis patients before and after non-surgical periodontal treatment (NSPT). The objectives of this research were to investigate changes in the levels and relative ratios of IL-34, OPG, and RANKL in the GCF of patients with periodontitis before and after NSPT.

MATERIALS AND METHODS

20 healthy participants (CTRL), 20 patients with stage 3-grade B periodontitis and 20 with stage 3-grade C periodontitis were recruited. GCF and clinical periodontal recordings were investigated at the baseline and 6 weeks after NSPT. Enzyme-linked immunosorbent assay (ELISA) were used for quantifying of GCF IL-34, RANKL and OPG levels and their relative ratios were calculated.

RESULTS

Greater values for GCF IL-34 and RANKL levels were found in the both of periodontitis groups than in CTRL group at baseline, whereas GCF OPG levels were statistically lower at baseline (P < 0.05). GCF IL-34 and RANKL levels decreased in the 6th week after NSPT in the both periodontitis groups, while the concentration OPG levels statistically increased (P < 0.05). Significantly positive correlations among the IL-34 with RANKL, sampled-site clinical attachment level (CAL), and gingival index (GI), whereas negative correlation with OPG were reported (P < 0.05).

CONCLUSIONS

GCF IL-34 levels was high in patients with periodontitis and decreased after NSPT and its levels showed positive correlations with RANKL/OPG ratio levels CAL and GI. Determining of IL-34 levels together with RANKL/OPG ratio in GCF may therefore be valuable in detecting high risk individuals with periodontitis patients.

MMP-8, TRAP-5, and OPG Levels in GCF Diagnostic Potential to Discriminate between Healthy Patients', Mild and Severe Periodontitis Sites

Biomarkers represent promising aids in periodontitis, host-mediate diseases of the tooth-supporting tissues. We assessed the diagnostic potential of matrix metalloproteinase-8 (MMP-8), tartrate-resistant acid phosphatase-5 (TRAP-5), and osteoprotegerin (OPG) to discriminate between healthy patients’, mild and severe periodontitis sites. Thirty-one otherwise healthy volunteers with and without periodontal disease were enrolled at the Faculty of Dentistry, University of Chile. Periodontal parameters were examined and gingival crevicular fluid was sampled from mild periodontitis sites (M; n = 42), severe periodontitis sites (S; n = 59), and healthy volunteer sites (H; n = 30). TRAP-5 and OPG were determined by commercial multiplex assay and MMP-8 by the immunofluorometric (IFMA) method. STATA software was used. All biomarkers showed a good discrimination performance. MMP-8 had the overall best performance in regression models and Receiver Operating Characteristic (ROC) curves, with high discrimination of healthy from periodontitis sites (area under the curve (AUC) = 0.901). OPG showed a very high diagnostic precision (AUC ≥ 0.95) to identify severe periodontitis sites (S versus H + M), while TRAP-5 identified both healthy and severe sites. As conclusions, MMP-8, TRAP-5, and OPG present a high precision potential in the identification of periodontal disease destruction, with MMP-8 as the most accurate diagnostic biomarker.

The effect of Phase 1 periodontal treatment on the salivary RANKL/OPG ratio in severe chronic periodontitis

Background

RANKL and OPG play an important role in bone resorption. The R A N K L O P G ratio increases in periodontal disease. The present study was conducted to evaluate the effect of Phase 1 periodontal treatment on the salivary R A N K L O P G ratio in patients with severe chronic periodontitis.

Materials and methods

Saliva samples were collected from 13 patients with severe chronic periodontitis and 14 healthy controls at baseline and then four weeks after the treatment using unstimulated spitting. The salivary levels of RANKL, OPG and R A N K L O P G ratio were investigated using the ELISA method.

Results

The findings of this study showed that the mean R A N K L O P G ratio was significantly higher in the patients with periodontal disease than in the healthy controls (P=0.001). Also, the R A N K L O P G ratio was significantly higher in the patients with a higher mean CAL (P=0/004). The comparison of the salivary R A N K L O P G ratio in patients with periodontal disease before and four weeks after the treatment showed a significant reduction in this value four weeks after the periodontal treatment (P=0/001).

Conclusion

The results of this study showed a direct relationship between the R A N K L O P G ratio and the severity of periodontal disease. Phase 1 of periodontal treatment was found to be effective in reducing the R A N K L O P G ratio. In other words, the R A N K L O P G ratio can be a good predictor of treatment success. Further long-term studies with larger sample sizes are required for confirming these results.

Effects of IL-10 and glucose on expression of OPG and RANKL in human periodontal ligament fibroblasts

The effects of interleukin-10 (IL-10) and glucose on mRNA and protein expression of osteoprotegerin (OPG), and its ligand, receptor activator of nuclear factor-κB ligand (RANKL), were investigated in human periodontal ligament fibroblasts (HPDLFs). Primary HPDLFs were treated with different concentrations of IL-10 (0, 1, 10, 25, 50, and 100 ng/mL) or glucose (0, 5.5, 10, 20, 30, and 40 mmol/L). Changes in mRNA and protein expression were examined using the reverse-transcription polymerase chain reaction (RT-PCR) and Western blot analysis, respectively. After IL-10 treatment, mRNA and protein levels of OPG were increased, while mRNA and protein levels of RANKL were decreased (P<0.05), both in a concentration-dependent manner. Glucose stimulation had the opposite concentration-dependent effect to that of IL-10 on OPG and RANKL expression. IL-10 upregulated OPG expression and downregulated RANKL expression, whereas high glucose upregulated RANKL and downregulated OPG in HDPLFs. Abnormal levels of IL-10 and glucose may contribute to the pathogenesis of periodontal disease.

Deficiency of cathepsin K prevents inflammation and bone erosion in rheumatoid arthritis and periodontitis and reveals its shared osteoimmune role

Using rheumatoid arthritis (RA) and periodontitis mouse models, we demonstrate that RA and periodontitis share many pathological features, such as deregulated cytokine production, increased immune-cell infiltration, increased expression of Toll-like receptors (TLRs), and enhanced osteoclast activity and bone erosion. We reveal that genetic deletion of cathepsin K (Ctsk) caused a radical reduction in inflammation and bone erosion within RA joint capsules and periodontal lesions, a drastic decrease in immune-cell infiltration, and a significant reduction in osteoclasts, macrophages, dendritic and T-cells. Deficiency of Ctsk greatly decreased the expression of TLR-4, 5, and 9 and their downstream cytokines in periodontal gingival epithelial lesions and synovial RA lesions. Hence, Ctsk may be targeted to treat RA and periodontitis simultaneously due to its shared osteoimmune role.

Effect of periodontal surgery on osteoprotegerin levels in gingival crevicular fluid, saliva, and gingival tissues of chronic periodontitis patients

Objectives. This study was undertaken to investigate the OPG profiles in gingival crevicular fluid (GCF), saliva, and gingival tissues of chronic periodontitis (CP) patients in response to open flap debridement (OFD). Subjects and Methods. The study included 30 subjects divided into 2 groups: 20 CP patients and 10 periodontally healthy subjects. Plaque index, gingival index, pocket depth, and clinical attachment level measurements were recorded for all subjects. GCF, salivary, and gingival samples were collected from all 30 subjects at baseline and 3 and 6 month after OFD from the 20 CP patients. GCF and salivary OPG levels were assessed by ELISA assay, while OPG expression in gingival tissues was examined by immunohistochemistry. Results. GCF, salivary and gingival OPG profiles were significantly higher in control subjects compared to CP patients at baseline (P < 0.001). Within CP group, OPG levels in GCF, saliva, and gingival samples showed a significant increase at 3 and 6 months after OFD (P < 0.001) compared to baseline. Although OPG values increased significantly in gingival samples and insignificantly in saliva after 3 months compared to 6 months, yet GCF levels were significantly decreased. Conclusions. OPG might be considered as a diagnostic and prognostic biomarker of periodontal bone destruction. This trial is registered with NCT02160613.

In vivo osteoprotegerin gene therapy preventing bone loss induced by periodontitis

OBJECTIVE

The objective of this study was to investigate the effects of osteoprotegerin (OPG) gene therapy on alveolar bone resorption caused by experimental periodontitis in rats, thus forming a foundation for potential clinical applications of OPG gene therapy in the treatment of periodontitis and peri-implantitis.

MATERIAL AND METHODS

To study the effects of OPG on alveolar bone protection, an experimental periodontitis model was used by placing a bacterial plaque retentive silk ligature in the gingival sulcus around the maxillary second molar tooth, injection of Porphyromonas gingivalis and high carbohydrate diet. A total of 30 Sprague-Dawley rats were randomly divided into three groups, with 10 rats in each group: group I (control) was treated with 10 μL normal saline injection; group II with 10 μL mock vector; and group III with 10 μL local OPG gene transfer by transfection with in vitro constructed pcDNA3.1-human OPG (pcDNA3.1-hOPG). A subperiosteal injection was done adjacent to the second molars on days 0, 7, 14 and 21. Four weeks later, all animals were killed and radiographic, histological and immunohistochemical examinations were performed. Statistical analysis included ANOVA and LSD-Bonferroni test.

RESULTS

Group III (OPG gene therapy) had significantly enhanced (p < 0.05) integrated optical density of OPG, had significantly decreased alveolar bone resorption volume and active osteoclast number (p < 0.05) through descriptive histological examination when compared with the other two groups at week 4.

CONCLUSION

Local recombinant OPG plasmid-mediated gene therapy suppresses osteoclastogenesis in vivo and inhibits alveolar bone height reduction caused by experimental periodontitis in rats. OPG gene therapy may be beneficial in preventing progressive periodontal bone loss.

Immunohistochemical expression of RANKL, RANK and OPG in gingival tissue of patients with periodontitis

OBJECTIVES

To evaluate the expression of the receptor activator of NF-κB (RANK), the receptor activator of NF-κB ligand (RANKL) and osteoprotegerin (OPG), in the gingival tissue of patients with periodontitis.

MATERIALS AND METHODS

Gingival tissue was obtained from 14 systemically healthy subjects with chronic periodontitis during conventional periodontal surgery. Immunohistochemistry was used to detect the expression of RANK, RANKL and OPG in the oral and periodontal pocket epithelium as well as in the connective tissue cells.

RESULTS

RANKL was negatively expressed in both oral and periodontal pocket epithelium. OPG was also negative or weakly positive in the whole epithelium. RANK showed moderate/strong positive staining mainly in the basal and suprabasal layer of oral and periodontal pocket epithelium. In most of the cases, more than 60% of the inflammatory cell infiltrate stained for RANK and RANKL. In these cases the intensity of the stained cells ranged from moderate-to-strong. In less than half of the cases, OPG was positive in more than 60% of the stained cells of the inflammatory cell infiltrate.

CONCLUSION

The RANK, RANKL and OPG proteins are differentially expressed in periodontal tissues and may play a major role in the bone loss occurring in periodontitis.

The RANKL-OPG system in clinical periodontology

BACKGROUND AND OBJECTIVES

The receptor activator of NF-κB ligand-osteoprotegerin (RANKL-OPG) bi-molecular system is the "bottle-neck" regulator of osteoclastogenesis and bone resorption, both in physiological and pathological conditions. This review aims to elaborate the current knowledge on RANKL and OPG in periodontal disease, and to evaluate their diagnostic and prognostic potential as biomarkers of the disease.

MATERIALS AND METHODS

To pursue this aim, electronic and manual searches were performed for identifying clinical and in vivo studies on RANKL and OPG in gingival tissue, gingival crevicular fluid, saliva and blood. Smoking and diabetes mellitus were also considered for their potential effects.

RESULTS

Papers fulfilling the inclusion criteria demonstrate that RANKL is up-regulated, whereas OPG is down-regulated in periodontitis, compared to periodontal health, resulting in an increased RANKL/OPG ratio. This ratio is further up-regulated in smokers and diabetics, and is not affected by conventional periodontal treatment.

CONCLUSIONS

The increased RANKL/OPG ratio may serve as a biomarker that denotes the occurrence of periodontitis, but may not necessarily predict on-going disease activity. Its steadily elevated levels post treatment may indicate that the molecular mechanisms of bone resorption are still active, holding an imminent risk for relapse of the disease. Additional adjunct treatment modalities that would "switch-off" the RANKL/OPG ratio may therefore be required.

Host-derived diagnostic markers related to soft tissue destruction and bone degradation in periodontitis

BACKGROUND

A major challenge in clinical periodontics is to find a reliable molecular marker of periodontal tissue destruction with high sensitivity, specificity and utility.

OBJECTIVES

The aim of this systematic review is to evaluate available literature on 'the utility of molecular markers of soft and hard periodontal tissue destruction'.

MATERIALS AND METHODS

Based on the focused question, 'What is the utility of molecular markers of soft and hard periodontal tissue destruction', an electronic and manual search was conducted for human studies presenting clinical data for the potential of molecular markers of tissue destruction in biofluids; gingival crevicular fluid (GCF), saliva, and serum.

RESULTS

Papers fulfilling the inclusion criteria were selected. All relevant data from the selected papers were extracted and recorded in separate tables for molecules in GCF, saliva, and serum.

CONCLUSION

Within the defined limits of the Problem/Population, Intervention, Comparison, Outcome, the present analysis reveals that (a) no single or combination of markers exists that can disclose periodontal tissue destruction adequately; (b) while the most fruitful source of biomarkers for periodontal destruction appears to be in molecules tightly related to bone and soft tissue destruction, this remains to be objectively demonstrated. Currently, clinical measurements are still the most reliable.