osteoprotegerin and Periapical-Periodontitis

Apical periodontitis caused by root canal infection is the most frequent pathological lesion in the jaws, mainly manifested as periapical granulomas and cysts. Understanding of the formation and progression of apical periodontitis as well as the identification of inflammatory biomarkers can help increase the knowledge of pathogenic mechanisms, improve the diagnosis and provide support for different therapeutic strategies. The objective of the present article is to review inflammatory biomarkers such as cytokines, chemokines, inflammatory cells, neuropeptides, RANK/RANKL/OPG system and other inflammatory markers and to relate these systems to the development and progression of pathological conditions related to apical periodontitis.

Topics: Biomarkers; Humans; Inflammation; Osteoprotegerin; Periapical Periodontitis; Root Canal Therapy

To summarize the collective in vitro, in vivo and clinical evidence of the involvement of the receptor activator of NF-κB ligand (RANKL)-osteoprotegerin (OPG) system, a system of two molecules controlling osteoclast differentiation and hard-tissue resorption, in pulpal and periapical pathophysiology.. A systematic search related to RANKL and/or OPG and pulp or periapical disease was conducted on Medline, Biosis, Cochrane, Embase and Web of Science databases using keywords and controlled vocabulary. No language restriction was applied. Two independent reviewers first screened titles and abstracts and then the full texts that were initially included. The reference lists of the identified publications were examined for additional titles.. A total of 33 papers were identified. In vitro studies (N = 11) revealed that pulpal cells can be stimulated by various inflammatory agents to produce RANKL, whilst many studies did not consider the RANKL/OPG ratio. Animal studies (N = 9) mostly focused on the time course and development of periapical lesions in relation to the RANKL-OPG system. Levels of RANKL and OPG in the necrotizing pulp were not investigated. Human studies (N = 13) showed a steady-state expression of OPG in the odontoblast layer. Conflicting results have been reported regarding the role of RANKL in active apical periodontitis, again because the correlation of this molecule with its inhibitor (OPG) was often disregarded.. There is relatively little information currently available that would highlight the specific role of RANKL and OPG in pulpal and periapical disease. OPG may play a protective role against internal resorption, whilst an increased periapical RANKL/OPG ratio might indicate bone resorption.

Topics: Alveolar Bone Loss; Animals; Cells, Cultured; Humans; Mice; Odontoblasts; Osteoprotegerin; Periapical Periodontitis; Pulpitis; Rats; Receptor Activator of Nuclear Factor-kappa B

Smoking can be considered a risk factor for chronic apical periodontitis (CAP). This study compared the immunoexpression of biomarkers receptor activator of nuclear factor kappa B ligand (RANKL), osteoprotegerin (OPG), osteopontin (OPN), and tumor necrosis factor alpha (TNF-α) in CAP in smokers and nonsmokers.. Twelve smokers and 12 nonsmokers diagnosed with CAP and indicated for tooth extraction were selected. Exclusion factors were teeth with a diagnosis of root fracture, previous endodontic treatment, or endoperiodontal injury, in addition to individuals with systemic diseases, under 18 years of age, users of anti-inflammatory and/or antibiotics in the last 3 months, and drug users. Specimens were processed for histopathologic and immunohistochemical analysis.. Qualitative analysis of RANKL expression showed 66.66% weak/moderate and 33.33% strong in smokers and 100% weak/moderate in nonsmokers. OPG and OPN expressions were 100% negative to focal in the smoker group and 50% negative to focal and 50% weak/moderate in the nonsmoker group. TNF-α was 25% negative to focal and 75% weak/moderate in the smoker group and 33.33% negative to focal and 66.66% weak/moderate in the nonsmoker group. Quantitative analysis of the data using the Mann-Whitney U test showed that there was a significant difference in the immunoexpression of RANKL (P < .05), OPG (P < .05), and OPN (P < .05), but there was no statistical difference in the immunoexpression of TNF-α (P > .05) between the 2 groups.. These findings suggest that smoking is capable of altering the inflammatory response, influencing the evolution of CAP.

Topics: Adolescent; Humans; Infant; NF-kappa B; Osteopontin; Osteoprotegerin; Periapical Periodontitis; Periodontitis; RANK Ligand; Smokers; Tumor Necrosis Factor-alpha

Topics: Bone Resorption; Cytokines; Epstein-Barr Virus Infections; Herpesvirus 4, Human; Humans; Interleukin-1; Interleukin-6; Jagged-1 Protein; Osteoprotegerin; Periapical Periodontitis; RANK Ligand; Receptor, Notch2; Signal Transduction; Tumor Necrosis Factor-alpha

To investigate the influence of chronic stress and adrenergic blockade in a rat model of apical periodontitis.. Thirty-two Wistar rats were submitted to an animal model of periapical lesion and randomly divided into 4 groups (n = 8): no stress (NS); stress + saline solution (SS); stress + β-adrenergic blocker (Sβ); stress + α-adrenergic blocker (Sα). The SS, Sβ and Sα groups were submitted to an animal model of chronic stress for 28 days and received daily injections of saline solution, propranolol (β adrenergic blocker) and phentolamine (α adrenergic blocker), respectively. After 28 days the animals were euthanized and the following analyses were carried out: a) serum corticosterone levels through Radioimmunoassay; b) measurement of serum levels of IL-1B, IL-6, IL-10 and IL-17 by enzyme-linked immunosorbent assay (ELISA); c) volume of periapical bone resorption by micro-computed tomography; d) histomorphometric analysis by staining with hematoxylin and eosin; e) expression of β-AR, α-AR, receptor activator of nuclear factor kappa-B ligand (RANKL) and osteoprotegerin (OPG) by immunohistochemistry; f) tartrate-resistant acid phosphatase (TRAP) staining; g) ex-vivo cytokine release followed by the stimulation with LPS in superfusion system, by ELISA.. SS group displayed significantly higher corticosterone levels than NS group (non-stressed). Higher IL-1β serum level was observed in the NS group (p < .05); compared to all stressed groups. Other cytokines were present in similar amounts in the serum of all groups. All groups presented similar periapical lesions. All groups presented moderate inflammatory infiltrate, without statistically significant differences between them. No differences were observed regarding β-AR, α-AR, Rank-L and OPG expression. The number of TRAP-positive cells was significantly decreased in the groups that received daily injections of adrenergic blockers. The IL-1β release followed LPS stimulation was significantly suppressed when the superfusion media contained propranolol (p < .05). Perfusion containing phentolamine induced a greater release of IL-10. TGF-β was significantly suppressed by phentolamine perfusion in the NS group (p < .05).. Chronic stress can significantly change the inflammatory cytokines release. Rank-L/OPG system and periapical lesion volume were not affected following the current method applied. The administration of adrenergic blockers was not able to modulate the inflammatory response but presented effectivity in reducing the number of osteoclasts in the periapical region.

Topics: Adrenergic Agents; Animals; Bone Resorption; Inflammation; Osteoprotegerin; Oxidative Stress; Periapical Periodontitis; RANK Ligand; Rats; Rats, Wistar; Receptors, Adrenergic; Stress, Physiological; X-Ray Microtomography

To investigate the regulation of inflammatory and osteoclastogenic signaling by 5-lipoxygenase (5-LO) in apical periodontitis induced by oral contamination of dental root canals in mice.. Apical periodontitis was induced in 5-lipoxygenase enzyme knockout (129-Alox5. Oral contamination of dental root canals induced recruitment of neutrophils and osteoclasts to the periodontal ligament, resulting in bone resorption. Absence of 5-LO did not impair neutrophil recruitment while osteoclastic formation was increased. Nonetheless, early bone resorption progressed similarly to lesions in wild-type animals. Interestingly, in the absence of 5-LO, the synthesis of mRNAs for cytokines, chemokines, and their receptors was significantly reduced while that of regulators of osteoclastogenesis (RANK, RANKL, and OPG) was increased in comparison with the corresponding levels in wild-type animals.. The 5-LO pathway plays a role in the stimulation of inflammatory mediator synthesis and inhibition of osteoclastogenesis in apical periodontitis in mice. However, the paradoxical inflammatory-osteoclastogenic signaling did not impair inflammatory cell recruitment and bone resorption during early development of the disease.

Topics: Animals; Arachidonate 5-Lipoxygenase; Bone Resorption; Inflammation; Mice; Mice, Knockout; Osteoclasts; Osteogenesis; Osteoprotegerin; Periapical Periodontitis; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B

To evaluate the relationship between systemic administration of probiotics and inflammation/resorption processes associated with apical periodontitis (AP) in a rat model.. Twenty-four male Wistar rats were used. AP was induced in the mandibular left/right first molars. The animals were arranged into three groups: Control, Lactobacillus rhamnosus and L. acidophilus. Probiotics were orally administered via gavage (10. There was no significant difference in the calcium and phosphorus levels in plasma amongst the groups (P > 0.05). The level of alkaline phosphatase was significantly higher in the groups that consumed probiotics (P < 0.05). A significantly lower volume of bone resorption was observed in groups that consumed probiotics (P < 0.05). The inflammatory infiltrates and the immunolabelling for RANKL and TRAP were significantly lower in probiotic groups when compared to the control (P < 0.05). Also, the OPG was significantly more immunolabelled in the L. acidophilus group than in the L. rhamnosus and control groups (P < 0.05).. Probiotic supplementation through gavage (L. rhamnosus and L. acidophilus) had a significant effect on the reduction of inflammation and bone resorption in apical periodontitis development in rats.

Topics: Animals; Bone Resorption; Inflammation; Male; Osteoprotegerin; Periapical Periodontitis; Probiotics; RANK Ligand; Rats; Rats, Wistar; X-Ray Microtomography

To investigate the effect of chronic alcohol consumption on apical periodontitis in rats.. Thirty-two male Wistar rats were arranged into four groups: Control (C): without apical periodontitis and nonalcoholic diet; (AL): without apical periodontitis and alcoholic diet; (AP): with apical periodontitis and nonalcoholic diet; and (AP + AL): with apical periodontitis and alcoholic diet. The alcoholic solution at 20% was given to the AL and AP + AL groups as the sole source of hydration throughout the experiment. AP was induced in the mandibular left first molars at the end of the 4th week. Weight changes and the amount of solid and liquid foods were recorded for 8 weeks. At the end, the animals were euthanized and the jaws removed followed by histological processing for histopathological and RANKL, OPG, TRAP and HIF-1α analyses. The Mann-Whitney test was used for nonparametric data, and anova followed by the Tukey test was performed for parametric data, with P < 0.05.. Animals that received the alcoholic diet had a lower weight gain than the other groups (P < 0.05). Control and AL groups did not have an inflammatory response in the periapical tissues. The median score of inflammatory infiltrate was significantly higher in the AP + AL group (2.5) compared to the AP group (1.5; P < 0.05). In the same comparison, AP + AL was associated with score 3 for RANKL and HIF-1α versus score 2 for AP group (P < 0.05). Moreover, the values for TRAP were 3.88 ± 0.70 cells mm. In rats, an alcoholic diet had a significant effect on the severity of apical periodontitis, exacerbating the inflammatory response and osteoclastogenesis.

Topics: Animals; Ethanol; Hypoxia-Inducible Factor 1, alpha Subunit; Male; Osteoclasts; Osteogenesis; Osteoprotegerin; Periapical Periodontitis; RANK Ligand; Rats; Rats, Wistar; Tartrate-Resistant Acid Phosphatase; Weight Gain

The exact mechanisms of periapical bone resorption have not been fully elucidated. This study aimed to analyze the expression of Notch signaling molecules (Notch2, Jagged1, and Hey1) and proinflammatory cytokines (tumor necrosis factor alpha [TNF-α], interleukin [IL]-1β, and IL-6) in human apical periodontitis lesions with different receptor activator of nuclear factor kappa B ligand (RANKL)/osteoprotegerin (OPG) ratios and determine their potential correlation.. The study group consisted of 50 periapical lesions collected in conjunction with apicoectomy. The relative gene expression of the investigated molecules (Notch2, Jagged1, Hey1, RANKL, OPG, TNF-α, IL-1β, and IL-6) in all tissue samples was analyzed using reverse transcriptase real-time polymerase chain reaction. The Student t test, Mann-Whitney U test, and Spearman correlation were used for statistical analysis.. Based on the RANKL/OPG ratio, periapical lesions were either RANKL predominant (RANKL > OPG, n = 33) or OPG predominant (RANKL < OPG, n = 17). Symptomatic lesions occurred more frequently in RANKL-predominant compared with OPG-predominant lesions (24 vs 7, P = .029). Notch2, Jagged1, Hey1, and TNF-α were significantly overexpressed in lesions with predominant RANKL compared with lesions with predominant OPG (P = .001, P = .001, P = .027, and P = .016, respectively). Significant correlations were observed between the investigated genes in periapical lesions.. Notch signaling appeared to be activated in periapical inflammation. An increase in Notch2, Jagged1, Hey1, and TNF-α expression in RANKL-predominant periapical lesions corroborates their joined involvement in extensive periapical bone resorption.

Topics: Adolescent; Adult; Aged; Bone Resorption; Cytokines; Female; Gene Expression; Humans; Inflammation Mediators; Male; Middle Aged; Osteoprotegerin; Periapical Periodontitis; RANK Ligand; Receptor, Notch2; Signal Transduction; Young Adult

The outcome of root canal treatment has been reported as intimately related to the host response. Genetic polymorphisms might be associated with apical periodontitis repair. The aim of this study was to evaluate the association between receptor activator of nuclear factor kappa B (RANK), receptor activator of nuclear factor kappa B ligand (RANKL), and osteoprotegerin (OPG) genetic polymorphisms with persistent apical periodontitis (PAP) in Brazilian subjects.. Subjects with at least 1 year of follow-up after nonsurgical root canal therapy were recalled. Sixty-four subjects with signs/symptoms of PAP and 86 subjects with root canal-treated teeth exhibiting healthy periradicular tissues (healed) were included. Genomic DNA was extracted from saliva and used for RANK (rs3826620), RANKL (rs9594738), and OPG (rs2073618) genotyping by real-time exact tests, and odds ratio were implemented using Epi Info 3.5.2 (Centers for Disease Control and Prevention, Atlanta, GA). A logistic regression analysis was also performed using the time of follow-up as the covariate. All tests were performed with an established alpha of 0.05 (P = .05).. An association between allele distribution and the polymorphism in RANK was observed. Subjects who carry the T allele had a lower risk of having PAP (P < .05). In RANKL polymorphism, the genotype distribution was statistically significant different between the PAP and healed groups (P = .05). The time of follow-up was associated with PAP (P < .05). In the logistic regression analysis using time as a covariant, RANK (P < .05) and RANKL (P < .05) were associated with PAP. The polymorphism rs2073618 in OPG was not associated with PAP (P > .05).. These findings suggest that polymorphisms in RANK and RANKL genes are associated with PAP.

Topics: Brazil; Humans; Osteoprotegerin; Periapical Periodontitis; Polymorphism, Genetic; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B

To investigate the effects of systemically administered melatonin on inflammation and alveolar bone resorption in rats with experimentally induced periapical lesions.. Thirty adult Sprague Dawley rats were divided equally into negative, positive control and melatonin groups. The pulp chambers of their mandibular first molars were exposed to the oral environment to induce experimental periapical lesions in the positive control and melatonin groups. The melatonin group received daily intraperitoneal injections of melatonin at a dose of 10 mg kg. The area of radiographic periapical bone loss was significantly smaller in rats that were given daily intraperitoneal injections of melatonin (P < 0.01). The histopathological scores of the melatonin group were significantly lower than those of positive control group (P < 0.01). Histomorphometrically, the area of periapical bone loss in the melatonin group was significantly smaller than the positive control group (P < 0.01). The expression of IL1-β, RANK and RANKL was significantly higher in the positive control group, whereas OPG was significantly higher in the melatonin group (P < 0.01). The number of osteoclasts was significantly greater in the positive control group by TRAP staining analyses (P < 0.01). The scores for bacteria localization using Brown-Brenn staining in the melatonin group was significantly lower than that of the positive control group (P < 0.01).. Melatonin demonstrated antiresorptive effects on bone associated with experimentally induced periapical lesions in rats via its anti-inflammatory activity. Further studies are necessary to evaluate its possible effects on the healing of periapical lesions.

Topics: Animals; Anti-Inflammatory Agents; Melatonin; Osteoclasts; Osteoprotegerin; Periapical Periodontitis; RANK Ligand; Rats; Rats, Sprague-Dawley; Tartrate-Resistant Acid Phosphatase

Topics: Adult; Biomarkers; Case-Control Studies; Chronic Disease; Female; Follow-Up Studies; Gene Expression Regulation; Humans; Interleukin-33; Male; Middle Aged; Osteoprotegerin; Periapical Periodontitis; Prognosis; RANK Ligand

To investigate whether apical periodontitis lesions infected by Epstein-Barr virus (EBV) exhibit higher levels of oxidative stress biomarkers [8-hydroxydeoxyguanosine (8-OHdG) and oxidized glutathione (GSSG)] and bone resorption regulators [receptor activator of nuclear factor (NF-κB) ligand (RANKL) and osteoprotegerin (OPG)] compared to EBV-negative periapical lesions and healthy pulp tissues.. The experimental group consisted of 30 EBV-positive and 30 EBV-negative periapical lesions collected in conjunction with apicoectomy. The pulp tissues of 20 impacted third molars were used as healthy controls. The qualitative and quantitative analysis of EBV was performed by nested and real-time polymerase chain reaction (PCR), respectively. The levels of RANKL and OPG were analysed by reverse transcriptase real-time PCR. The levels of 8-OHdG and GSSG were determined by enzyme-linked immunosorbent assay (ELISA). Mann-Whitney U-test and Spearman's correlation were used for statistical analysis.. The levels of RANKL, OPG, 8-OHdG and GSSG were significantly higher in apical periodontitis lesions compared to healthy pulp controls (P = 0.001, P < 0.001, P < 0.001 and P < 0.05, respectively). RANKL and OPG mRNA expression was significantly higher in EBV-positive compared to EBV-negative periapical lesions (P < 0.05). There was no significant correlation between EBV copy numbers and levels of RANKL, OPG, 8OH-dG and GSSG in apical periodontitis.. Levels of bone resorption regulators and oxidative stress biomarkers were increased in apical periodontitis compared to healthy pulp tissues. EBV-positive periapical lesions exhibited higher levels of RANKL and OPG compared to EBV-negative periapical lesions. EBV may contribute to progression of apical periodontitis via enhanced production of bone resorption regulators.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Adult; Biomarkers; Bone Resorption; Case-Control Studies; Deoxyguanosine; Enzyme-Linked Immunosorbent Assay; Epstein-Barr Virus Infections; Female; Glutathione; Herpesvirus 4, Human; Humans; Male; Osteoprotegerin; Oxidative Stress; Periapical Periodontitis; RANK Ligand; Real-Time Polymerase Chain Reaction

To evaluate the association between the presence of selected bacterial species/groups in the apical root canal and expression of mediators of soft and bone tissue destruction in apical periodontitis lesions. Relationships between bacteria and some other features of apical periodontitis were also investigated.. Seventeen freshly extracted teeth with pulp necrosis and apical periodontitis were included. The apical root segment was sectioned and cryopulverized; DNA was extracted and evaluated for the presence of 9 bacterial species/groups using real-time polymerase chain reaction. Lesions were processed for histopathological and immunohistochemical analyses, which targeted matrix metalloproteinase-2 (MMP-2) and -9 (MMP-9), receptor activator of NFκB (RANK), RANK ligand (RANKL) and osteoprotegerin (OPG). Associations of the target bacteria with expression of these mediators, presence of symptoms, lesion size and histopathological diagnosis were evaluated. Data were analysed using the chi-square, Fisher's exact, Mann-Whitney and Pearson tests. P values lower than 0.05 were considered significant.. All pulverized apical root samples were positive for bacteria. The most prevalent taxa were Actinobacteria (53%), Streptococcus species (35%), Fusobacterium species and Parvimonas micra (18%). The target mediators exhibited a high mean expression in the lesions (MMP-2: 82%; MMP-9: 73%; RANK: 78%; RANKL; 81%; OPG; 83%). Mean RANKL:OPG ratio was significantly higher in granulomas than cysts (P < 0.05, Mann-Whitney test). Actinobacteria were associated with granulomas, higher MMP-2 expression, lower OPG expression, and higher RANKL:OPG ratio (P < 0.05 for all, Fisher's exact test or Mann-Whitney test). No other significant associations were found.. Actinobacteria may play an important role in the active phase of soft and bone tissue destruction in apical periodontitis.

Topics: Adult; Aged; Dental Pulp Cavity; Dental Pulp Necrosis; Female; Fusobacterium; Humans; Male; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Matrix Metalloproteinases; Middle Aged; Osteoprotegerin; Periapical Periodontitis; RANK Ligand; Real-Time Polymerase Chain Reaction; Receptor Activator of Nuclear Factor-kappa B; Streptococcus; Tooth Apex

Clastic cells, originating from the monocyte-macrophage lineage, resorb mineralized tissues. In periapical periodontitis, alveolar bone around the tooth apex becomes resorbed; however, the roots of the teeth are often left intact by yet unknown mechanisms. Here, we examined the status of clastic cells in a periapical periodontitis model in mice.. Periapical periodontitis was induced by performing pulp exposure on the maxillary first molar. The contralateral maxillary first molar was used as a control. The maxillae were harvested, fixed, and subjected to μCT scanning and three-dimensional volumetric analysis. TRAP staining was performed, and osteoclasts were quantified. Immunohistochemical staining was performed for RANKL, OPG, and F4/80, a marker for macrophages.. At the apex of the tooth, pulp exposure resulted in periapical radiolucency with mineralized tissues at the surrounding bone surfaces but not on the root surfaces. Histologically, clastic cells were present on the bone surfaces but absent around the root surfaces. Expression of F4/80 and RANKL was not found at close proximity to the root surfaces, but OPG was globally expressed.. The absence of clastic cells around the root surface of pulp-exposed teeth, in part, is associated with the lack of macrophages and RANKL expression.

Topics: Alveolar Process; Animals; Antigens, Differentiation; Dental Pulp; Disease Models, Animal; Female; Macrophages; Maxilla; Mice; Molar; Osteoclasts; Osteoprotegerin; Periapical Periodontitis; RANK Ligand; Tooth Root; X-Ray Microtomography

To evaluate and correlate, in the same research, the mRNA expression and the staining of RANK, RANKL, OPG, TLR2 and MyD88 by immunohistochemistry in the apical periodontitis (AP) progression in mice.. AP was induced in the lower first molars of thirty-five C57BL/6 mice. They were assigned to four groups according to their euthanasia periods (G0, G7, G21 and G42). The jaws were removed and subjected to histotechnical processing, immunohistochemistry and real-time reverse transcription-PCR (qRT-PCR). Data were analyzed with parametric and nonparametric tests (α=0.05).. An increase of positive immunoreactivity for RANK, RANKL, OPG, TLR2 and MyD88 was observed over time (p<0.05). The RANKL expression was different between the groups G0 and G42, G21 and G42 (p=0.006), with G42 presenting the higher expression in both comparations. The OPG expression was statistically different between the groups G0 and G7, G7 and G21 and G7 and G42 (p<0.001), with G7 presenting higher expression in all the time points. The TLR2 expression was different between the groups G0 and G42 (p=0.03), with G42 showing the higher expression. The MyD88 expression presented a statistical significant difference between groups G7, G21 and G42 compared with G0 (p=0.01), with G0 presenting the smallest expression in all the comparisons. The Tnfrsf11/Tnfrsf11b (RANKL/OPG) ratio increased with the AP progression (p=0.002). A moderate positive correlation between MyD88 and RANKL (r=0.42; p=0.03) and between MyD88 and TLR2 (r=0.48; p<0.0001) was observed.. The expression of the RANK, RANKL, OPG, MyD88 and TLR2 proteins as well as the ratio Tnfrsf11/Tnfrsf11b (RANKL/OPG) increased with AP progression. There was also a moderate positive correlation between the expression Myd88-Tnfrsf11 and Tlr2-Myd88, suggesting the relevance of Tlr2-Myd88 in bone loss due to bacterial infection.

Topics: Animals; Disease Progression; Gene Expression; Immunohistochemistry; Male; Mice, Inbred C57BL; Myeloid Differentiation Factor 88; Osteoprotegerin; Periapical Periodontitis; RANK Ligand; Reference Values; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Time Factors; Toll-Like Receptor 2

The study aimed to verify the potential correlation between the detected amount of gram-negative bacteria and the radiographic sizes of the lesions in patients with symptomatic and asymptomatic apical periodontitis. Furthermore, to evaluate whether the expression of receptor activator of NF-κB ligand (RANKL) and osteoprotegerin (OPG) and the RANKL/OPG ratio are differentially regulated in both groups.. Twenty patients with periapical lesions were divided into two groups: symptomatic (SYM) n=10 and asymptomatic (ASYM) n=10. After periapical surgery, the lesions were collected and processed for histological examination, and immunohistochemistry. The percentage of RANKL- and OPG-immunopositive areas relative to the total area of the microscopic field was calculated. For gram staining, the number of gram-negative cells per microscopic field was assessed. The radiographs of each patient were processed and measured. The Student's t-test and the Pearson correlation coefficient were performed.. The SYM group showed a significantly higher number of gram-negative cells (p=0.007) when compared to the ASYM group. A higher number of gram-negative bacteria occurred more frequently in larger periapical lesions and the SYM group (p=0.03). The expression for RANKL and OPG and the RANKL/OPG ratio were not significantly different between the groups. There was a significant positive correlation between the number of bacteria and OPG levels in the SYM group (p=0.01).. The number of bacteria seems to influence the symptoms and the radiographic size of a periapical lesion. Gram-negative bacteria may play an important role in OPG activity in the SYM group.

Topics: Adult; Asymptomatic Infections; Female; Gram-Negative Bacteria; Gram-Negative Bacterial Infections; Humans; Male; Osteoprotegerin; Periapical Periodontitis; RANK Ligand; Young Adult

The aim of this study is to assess the levels and diagnostic accuracy of a set of bone resorption biomarkers, including TRAP-5, RANKL, and OPG in symptomatic and asymptomatic apical lesions and controls.. Apical tissues from symptomatic and asymptomatic apical periodontitis patients and periodontal ligaments from healthy teeth extracted for orthodontic reasons were processed for tissue homogenization and the levels of TRAP-5, RANKL, and OPG were determined by multiplex assay. Marker levels were analyzed by Kruskal Wallis test, and diagnostic accuracy was analyzed with ROC curves.. Higher levels of RANKL, OPG, and RANKL/OPG ratio were determined in both types of apical lesions compared to healthy periodontal ligament, whereas higher TRAP-5 levels were found only in symptomatic apical lesions (p < 0.05). OPG, RANKL, and RANKL/OPG ratio showed diagnostic potential to identify apical lesions versus healthy controls (AUC = 0.69, p < 0.05); while TRAP-5 showed a potential to discriminate symptomatic versus asymptomatic apical periodontitis (AUC = 0.71, p < 0.05) and healthy controls (AUC = 0.83, p < 0.05).. Apical lesions showed higher RANKL and OPG levels than healthy tissues. TRAP-5 levels were the highest in symptomatic apical lesions, suggesting that these represent a progressive state, and showed diagnostic potential.. Clinically symptomatic apical periodontitis might represent biologically progressive apical lesions based on TRAP5 levels. TRAP5 has diagnostic potential to identify these lesions, representing a candidate prognostic biomarker.

Topics: Adolescent; Biomarkers; Bone Resorption; Female; Humans; Male; Middle Aged; Osteoprotegerin; Periapical Periodontitis; Periodontal Ligament; RANK Ligand; Tartrate-Resistant Acid Phosphatase

This study assessed the immune-inflammatory profile and the expression of bone resorption activators receptor activator of nuclear factor kappa B ligand (RANKL) and inhibitor osteoprotegerin (OPG) in apical periodontitis (n = 20) that persisted after root canal retreatment.. Immunohistochemistry was used to characterize lymphocyte populations (CD3+, CD45RO+, CD8+, and FoxP3+ cells), macrophages (CD68+), RANKL+ and OPG+ cells in persistent apical periodontitis (PAP) and primary periapical lesions (PPLs). By using quantitative real-time polymerase chain reaction, the mRNA expression of RANKL and OPG in PAP and periodontal ligament from healthy teeth was comparatively analyzed. The data were analyzed by Mann-Whitney, Pearson χ2, and Wilcoxon tests (5% level).. PAP showed an elevated number of FoxP3+ cells compared with PPL (P < .001). The number of CD68+ cells was reduced in the PAP samples compared with the PPLs (P < .001). Similar number of other lymphocyte populations was observed in PAP and PPLs (P > .05 for all comparisons). No differences in the RANKL, OPG, and immune-inflammatory cells were demonstrated when comparing PAP microscopically classified as cyst with those classified as granulomas (P > .05 for all comparisons). The assessment of mRNA expression revealed higher levels of RANKL and OPG in PAP compared with the periodontal ligament from healthy teeth (control) samples (P < .001). Also, a greater expression of RANKL in comparison with OPG was observed in PAP (P < .001).. These findings indicate that PAP consists of biologically active lesions that demonstrate potential of bone resorption (higher expression of RANKL) and is characterized by an immune-inflammatory cell profile that suggests a suppressive and regulatory environment (higher number of FoxP3+ cells and lower number of macrophages) favorable to more chronic clinical behavior.

Topics: Adult; Dental Pulp Cavity; Female; Humans; Lymphocytes; Macrophages; Male; Osteoprotegerin; Periapical Periodontitis; RANK Ligand; Retreatment; Root Canal Therapy; Treatment Failure

Although studies have recently shown that osteocytes embedded in mineralized bone matrix play an important role in bone diseases, the participation of cementocytes in apical periodontitis has not been evaluated. The aim of the present study was to evaluate the possible involvement of cementocytes in the development of apical periodontitis.. Apical periodontitis was experimentally induced in the lower first molars of wild-type mice by pulp exposure to the oral environment. At 0, 7, 21, and 42 days after pulp infection, the animals were euthanized, and the jaws were prepared for analysis under conventional and fluorescence microscopy (morphologic and morphometric analysis), immunohistochemistry and immunofluorescence (receptor activator of nuclear factor kappa-B [RANK], receptor activator of the nuclear factor kappa-B ligand [RANKL], and osteoprotegerin [OPG]), enzyme histochemistry (osteoclasts and cementoclasts), and real-time polymerase chain reaction (RANK, RANKL, OPG, and cathepsin K).. At 7, 21, and 42 days after pulp exposure, there was a progressive increase in periodontal ligament, cementum and bone resorption areas, osteoclasts, and cementoclast counts as well as higher messenger RNA levels of RANK, RANKL, OPG, and cathepsin K. In intact teeth, cementocytes and osteocytes did not express RANKL. After infection, RANKL was strongly expressed in cementocytes, but not in osteocytes, and its expression increased with lesion progression.. Our findings show that cementocytes express RANKL in response to endodontic infection and may be involved in the pathogenesis of apical periodontitis.

Topics: Animals; Cathepsin K; Dental Cementum; Disease Models, Animal; Immunohistochemistry; Male; Mice; Mice, Inbred C57BL; Microscopy, Fluorescence; Molar; Osteoprotegerin; Periapical Periodontitis; RANK Ligand; Real-Time Polymerase Chain Reaction

Periapical bone loss is one of the prominent pathological and clinical features of periapical periodontitis. Previous studies have demonstrated that follicle‑stimulating hormone (FSH) could directly affect skeletal remodelling by stimulating the formation and the function of osteoclasts in vitro and in vivo. However, the effect of FSH on periapical bone loss remained to be fully elucidated. In the current study, a rat model was established in order to verify the effect of FSH in experimental periapical lesions. It was identified that FSH aggravated the bone loss of periapical lesions. In addition, RANKL‑, TRAP‑, TNF‑α‑ and IL‑1β‑positive cells were increased significantly in FSH‑treated groups, which indicated that the function of FSH in bone loss may be mediated through the increasing activity of osteoclasts and the increased secretion of inflammatory cytokines. The results of the current study suggested that FSH, independent of oestrogen, may aggravate periapical bone loss by FSH receptors, which may serve an important role in the immune and inflammatory response of the host to root canal and periradicular infection during menopause.

Topics: Animals; Female; Follicle Stimulating Hormone; Humans; Interleukin-1beta; Osteoclasts; Osteoporosis, Postmenopausal; Osteoprotegerin; Ovariectomy; Periapical Periodontitis; Periapical Tissue; RANK Ligand; Rats; Rats, Sprague-Dawley; Receptors, FSH; Tumor Necrosis Factor-alpha

Chronic inflammatory processes in periapical tissues caused by etiological agents of endodontic origin lead to apical periodontitis. Apart from bacteria, two herpesviruses, Epstein-Barr virus (EBV) and Human cytomegalovirus (HCMV) are recognized as putative pathogens in apical periodontitis. Although previous reports suggest the involvement of EBV in the pathogenesis of apical periodontitis, its exact role in periapical bone resorption has not yet been fully elucidated. We hypothesize that EBV infection in apical periodontitis is capable of inducing periapical bone resorption via stimulation of reactive oxygen species (ROS) overproduction. Increased levels of ROS induce expression of receptor activator of nuclear factor kappa B (NF-κB) ligand (RANKL). RANKL binding to receptor activator of nuclear factor κB (RANK) present on the surface of preosteoclasts induces their maturation and activation which consequently leads to bone resorption. The potential benefit of antiviral and antioxidant-based therapies in periapical bone resorption treatment remains to be assessed.

Topics: Animals; B-Lymphocytes; Bone Resorption; Epithelial Cells; Epstein-Barr Virus Infections; Herpesvirus 4, Human; Humans; Inflammation; Models, Theoretical; Osteoclasts; Osteoprotegerin; Periapical Periodontitis; RANK Ligand; Reactive Oxygen Species; Receptor Activator of Nuclear Factor-kappa B

Apical periodontitis is an inflammation and destruction of periapical tissues. Matrix metalloproteinase-9 (MMP-9) is thought to be involved in periapical lesion formation and progression. The aim of this study was to evaluate the lesion progression in MMP-9 knockout (KO) mice compared with that in control mice (wild type [WT]).. The pulps of mouse mandibular first molars were exposed; animals were killed at 0, 7, 14, 21, and 28 days after surgery. Hematoxylin-eosin-stained sections were observed for the description of pulpal, apical, periapical features, and the periapical lesion size. The periapical lesion size was further measured with micro-computed tomographic imaging. The number of osteoclasts was also counted by tartrate-resistant acid phosphatase histoenzymology. Real-time polymerase chain reaction and immunohistochemistry were used to analyze the expression levels of receptor activator of NF-κB (RANK), receptor activator of NF-κB ligand (RANKL), osteoprotegerin (OPG), interleukin-1 beta (IL-1β), tumor necrosis factor alpha (TNF-α), MMP-2, and MMP-8.. There was a significant difference (P < .05) between the 2 types of animals regarding the periapical lesion size, which was larger in MMP-9 KO animals. No significant differences (P > .05) were found between WT and MMP-9 KO mice related to the osteoclast number as well as the pulpal, apical, and periapical features. More neutrophil cells were observed in MMP-9 KO animals than WT mice (P < .05). The expression levels of RANK, RANKL, OPG, IL-1β, TNF-α, MMP-2, and MMP-8 were found up-regulated in MMP-9 KO mice (P < .05).. MMP-9 KO animals developed larger periapical lesions with greater inflammatory response, indicating an important role of MMP-9 in the host's immune and inflammatory response to root canal and periradicular infection.

Topics: Acid Phosphatase; Animals; Cell Count; Dental Pulp Exposure; Disease Progression; Interleukin-1beta; Isoenzymes; Male; Matrix Metalloproteinase 2; Matrix Metalloproteinase 8; Matrix Metalloproteinase 9; Mice; Mice, Knockout; Neutrophils; Osteoclasts; Osteoprotegerin; Periapical Periodontitis; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Tartrate-Resistant Acid Phosphatase; Tumor Necrosis Factor-alpha; X-Ray Microtomography

The dental pulp space can become infected due to a breach in the surrounding hard tissues. This leads to inflammation of the pulp (pulpitis), soft tissue breakdown, and finally to bone loss around the root apex (apical periodontitis). The succession of the molecular events leading to apical periodontitis is currently not known. The main inflammatory mediator associated with neutrophil chemotaxis is interleukin-8 (IL-8), and with bone resorption the dyad of receptor activator of NF-κB ligand (RANKL) and osteoprotegerin (OPG). The levels of RANKL, OPG and IL-8 were studied in periapical tissue fluid of human teeth (n = 48) diagnosed with symptomatic irreversible pulpitis (SIP) and asymptomatic apical periodontitis (AAP). SIP represents the starting point, and AAP an established steady state of the disease. Periapical tissue fluid samples were collected using paper points and then evaluated using enzyme-linked immunosorbent assays (ELISAs). Target protein levels per case were calibrated against the corresponding total protein content, as determined fluorometrically. RANKL was expressed at significantly higher levels in SIP compared to AAP (P < 0.05), whereas OPG was under the detection limit in most samples. In contrast, IL-8 levels were significantly lower in SIP compared to AAP (P < 0.05). Spearman's correlation analysis between RANKL and IL-8 revealed a significantly (P < 0.05) negative correlation between the two measures (rho = -.44). The results of this study suggest that, in the development of apical periodontitis, periapical bone resorption signaling, as determined by RANKL, occurs prior to inflammatory cell recruitment signaling, as determined by IL-8.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Bone Resorption; Dental Pulp; Enzyme-Linked Immunosorbent Assay; Female; Humans; Inflammation; Interleukin-8; Male; Middle Aged; Osteoprotegerin; Periapical Periodontitis; Periapical Tissue; Pulpitis; RANK Ligand; Young Adult

The aim of this study was to characterize the formation and progression of experimentally induced periapical lesions in TLR2 knockout (TLR2 KO) mice.. Periapical lesions were induced in molars of 28 wild type (WT) and 27 TLR2 KO mice. After 7, 21, and 42 days, the animals were euthanized, and the mandibles were subjected to histotechnical processing. Hematoxylin-eosin-stained sections were examined under conventional light microscopy for the description of pulpal, apical, and periapical features and under fluorescence microscopy for the determination of the periapical lesion size. The subsequent sections were evaluated by tartrate resistant acid phosphatase histoenzymology (osteoclasts), Brown and Brenn staining (bacteria), and immunohistochemistry (RANK, RANKL, and OPG). Data were analyzed by the Mann-Whitney U and Kruskal-Wallis tests (α = 0.05).. The WT group showed significant differences (P < .05) in the periapical lesion size and the osteoclast number between 7 and 42 days and between 21 and 42 days. In the TLR2 KO group, significant differences (P < .05) in the periapical lesion size and the osteoclast number were found between 7 days and the other periods. There was a significant difference (P < .05) between the 2 types of animal regarding the periapical lesion size, which was larger in the TLR2 KO animals. No significant differences (P > .05) were found between WT and TLR2 KO mice related to the pulpal, apical, and periapical features; bacteria localization; and immunohistochemical results (except for RANK expression).. TLR2 KO animals developed larger periapical lesions with a greater number of osteoclasts, indicating the important role of this receptor in the host's immune and inflammatory response to root canal and periradicular infection.

Topics: Animals; Cell Count; Dental Pulp Necrosis; Male; Mice; Mice, Knockout; Neutrophils; Osteoclasts; Osteoprotegerin; Periapical Periodontitis; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Toll-Like Receptor 2

Metformin, one of the antihyperglycemic agents commonly used for the treatment of type 2 diabetes, was shown to inhibit osteoclast formation. The current study aimed to investigate the effects of systemically administered metformin on alveolar bone resorption and on the ratio of receptor activator of nuclear factor kappa B ligand/osteoprotegerin (RANKL/OPG) in rats subjected to experimental periapical lesions.. Forty adult male Wistar rats were divided equally into control and experimental groups, and the pulp chambers of their mandibular first molars were exposed to the oral environment to induce periapical lesions. The experimental group received daily intramuscular injections of metformin at 40 mg/kg doses, whereas the control group received only the saline vehicle. The injections were initiated 1 day before the periapical lesion induction and then were continued daily throughout the entire experimental period. Two or 4 weeks after pulp exposure, the rats were killed, and the mandibles were prepared for histologic analysis, enzyme histochemistry, immunohistochemistry, and immunofluorescence.. The number of RANKL-positive and tartrate-resistant acid phosphatase (TRAP)-positive cells in the metformin-treated groups decreased on day 14, whereas the number of OPG-positive cells increased on day 28. The periapical bone loss area in the metformin-treated group significantly decreased on day 28 compared with the control group.. Metformin inhibits the periapical lesions possibly by lowering the RANKL/OPG ratio, subsequently reducing the number of osteoclasts and bone resorption areas.

Topics: Alveolar Bone Loss; Animals; Anti-Inflammatory Agents; Bone Remodeling; Injections, Intramuscular; Male; Metformin; Osteoclasts; Osteoprotegerin; Periapical Periodontitis; RANK Ligand; Rats; Rats, Wistar

Nitric oxide (NO) derived from inducible nitric oxide synthase (iNOS) plays an important role in host defense, as well as in inflammation-induced tissue lesions. Here we evaluated the role of NO in bone loss in bacterial infection-induced apical periodontitis by using iNOS-deficient mice (iNOS(-/-)). The iNOS(-/-) mice developed greater inflammatory cell recruitment and osteolytic lesions than WT mice. Moreover, tartrate-resistant acid-phosphatase-positive (TRAP(+)) osteoclasts were significantly more numerous in iNOS(-/-) mice. Furthermore, the increased bone resorption in iNOS(-/-) mice also correlated with the increased expression of receptor activator NF-kappaB (RANK), stromal-cell-derived factor-1 alpha (SDF-1 alpha/CXCL12), and reduced expression of osteoprotegerin (OPG). These results show that NO deficiency was associated with an imbalance of bone-resorption-modulating factors, leading to severe infection-stimulated bone loss.

Topics: Acid Phosphatase; Actinomycosis; Alveolar Bone Loss; Animals; Bacterial Infections; Bacteroidaceae Infections; Biomarkers; Cell Count; Cell Movement; Chemokine CXCL12; Dental Pulp Exposure; Isoenzymes; Mice; Mice, Inbred C57BL; Mice, Inbred Strains; Nitric Oxide; Nitric Oxide Synthase Type II; Osteoclasts; Osteolysis; Osteoprotegerin; Periapical Periodontitis; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Tartrate-Resistant Acid Phosphatase

To investigate the expression of key mediators that regulate bone resorption, receptor activator of nuclear factor-kappaB ligand (RANKL) and osteoprotegerin (OPG) in human periapical granuloma (PG) and radicular cyst (RC) characterized by periapical bone destruction.. Immunohistochemical technique was performed using monoclonal antibody to detect RANKL and OPG expression in PG (n= 20 ) and RC (n= 20 ). As control group, healthy periodontal ligament tissues (n = 6 ) were obtained from teeth with orthodontic indication of extraction.. The RANKL protein expression was significantly higher in PG (43.74 +/- 8.40) and RC (40.33 +/- 7.53) than in control group (15.47 +/- 2.59, P=0.000) , but no statistical significance could be found between PG and RC groups(P=0.161) .The expression of OPG in PG (27.81 +/- 5.17), RC (26.35 +/- 3.86) and control group (24.33 +/- 3.50) show no statistical significance (P >0.05). Moreover, RANKL/OPG ratio in PG (1.59 +/- 0.26) and RC (1.54 +/- 0.24) was much higher than that in control group (0.64 +/- 0.10, P=0.000), however the ratio of RANKL/OPG showed no significant difference between PG and RC groups (P= 0.504) .. RANKL and OPG were observed in the periapical lesions. RANKL may be responsible for bone resorption in periapical lesions. RANKL and OPG may play an important role in the development of periapical lesions.

Topics: Chronic Disease; Humans; Osteoprotegerin; Periapical Periodontitis; RANK Ligand

The object of this study was to elucidate the kinetics of receptor activator of NFkB ligand (RANKL), RANK, osteoprotegerin (OPG), and cytokine expressions in experimentally induced rat periapical lesions.. The mRNA expressions of RANKL, RANK, OPG, and cytokines in experimentally induced rat periapical lesions were evaluated by real-time PCR. The lesions were induced in male Wistar rats (n = 48, 5 weeks of age) by unsealed pulp exposure of the lower first molars.. Expression of RANKL was up-regulated at the beginning of lesion expansion, and expression ratio of RANKL against OPG, a competitor of RANKL, peaked at 2 and 3 weeks. Expression of inflammatory cytokines, such as TNF-alpha, IL-1alpha, and IL-1beta also increased at this stage, suggesting contribution of synergic effects of RANKL and proinflammatory cytokine signaling to lesion expansion. Most of RANKL+ cells were fibroblastic, but few of them were T cells.. Expression of RANKL and proinflammatory cytokines was correlated with periapical lesion expansion.

Topics: Acid Phosphatase; Animals; Cytokines; Immunoenzyme Techniques; Interleukin-10; Interleukin-1alpha; Interleukin-1beta; Isoenzymes; Kinetics; Male; Osteoprotegerin; Periapical Periodontitis; RANK Ligand; Rats; Rats, Wistar; Receptor Activator of Nuclear Factor-kappa B; Receptors, Antigen, T-Cell, alpha-beta; Reverse Transcriptase Polymerase Chain Reaction; Tartrate-Resistant Acid Phosphatase; Tumor Necrosis Factor-alpha