osteoprotegerin and Root-Resorption

The objective of this scoping review was to systematically explore the current knowledge of cellular and molecular processes that drive and control trauma-associated root resorption, to identify research gaps and to provide a basis for improved prevention and therapy.. Four major bibliographic databases were searched according to the research question up to February 2021 and supplemented manually. Reports on physiologic, histologic, anatomic and clinical aspects of root resorption following dental trauma were included. Duplicates were removed, the collected material was screened by title/abstract and assessed for eligibility based on the full text. Relevant aspects were extracted, organized and summarized.. 846 papers were identified as relevant for a qualitative summary. Consideration of pathophysiological mechanisms concerning trauma-related root resorption in the literature is sparse. Whereas some forms of resorption have been explored thoroughly, the etiology of others, particularly invasive cervical resorption, is still under debate, resulting in inadequate diagnostics and heterogeneous clinical recommendations. Effective therapies for progressive replacement resorptions have not been established. Whereas the discovery of the RANKL/RANK/OPG system is essential to our understanding of resorptive processes, many questions regarding the functional regulation of osteo-/odontoclasts remain unanswered.. This scoping review provides an overview of existing evidence, but also identifies knowledge gaps that need to be addressed by continued laboratory and clinical research.

Topics: Humans; Osteoclasts; Osteoprotegerin; Root Resorption

When orthodontic patients desire shorter treatment times with aesthetic results and long-term stability, it is important for the orthodontist to understand the potential limitations and problems that may arise during standard and/or technology-assisted accelerated treatment. Bone density plays an important role in facilitating orthodontic tooth movement (OTM), such that reductions in bone density can significantly increase movement velocity. Lifestyle, genetic background, environmental factors, and disease status all can influence a patients' overall health and bone density. In some individuals, these factors may create specific conditions that influence systemic-wide bone metabolism. Both genetic variation and the onset of a bone-related disease can influence systemic bone density and local bone density, such as observed in the mandible and maxilla. These types of localized density changes can affect the rate of OTM and may also influence the risk of unwanted outcomes, i.e., the occurrence of dental external apical root resorption (EARR).

Topics: Bone Density; Bone Diseases, Metabolic; Bone Remodeling; Humans; Interleukin-1beta; Mandible; Maxilla; Osteoprotegerin; Receptors, Purinergic P2X7; Root Resorption; Tooth Movement Techniques

To review studies investigating if genetic factors play a role in external apical root resorption (EARR) during orthodontic treatment. Heritability estimation in human sib-pairs, comparison of multiple inbred mouse strains, human sib-pair linkage and parents-child trio association studies, and two gene (Il-1b, and P2rx7) knock out mouse models. Heritability for EARR of the maxillary central incisors concurrent with orthodontic treatment is 0.8. DBA/2J, BALB/cJ, and 129P3/J inbred mouse strains are highly susceptible (p < .05) to histological root resorption (RR) associated with orthodontic force (RRAOF), whereas A/J, C57BL/6J and SJL/J mice are resistant. Non-parametric sibling pair linkage analysis identified evidence of linkage (LOD = 2.5; p = 0.02) of EARR with microsatellite D18S64 (tightly linked to TNFRSF11A, also known as RANK). There is significant linkage disequilibrium of IL-1B (p = 0.0003), and OPG (p = 0.003) with EARR. RRAOF increases in Il1b KO (p < or = 0.013), and increases in P2rx7 KO (p < 0.02) mice compared to wild-type. Genetic factors play a marked role in EARR concurrent with orthodontic force, accounting for one-half to two-thirds of the variation. Two pathways for this may involve: 1) activation control of osteoclasts through the ATP/P2XR7/IL-1B inflammation modulation pathway; and 2) RANK/RANKL/OPG osteoclast activation control. Histological RR occurs and is typically healed. If resorption outpaces healing, then EARR develops. Normal and parafunctional forces, as well as orthodontic forces, may add to or interact with the individual's susceptibility to pass the threshold of developing EARR.

Topics: Animals; Disease Models, Animal; Diseases in Twins; Genetic Linkage; Genetic Predisposition to Disease; Humans; Interleukin-1beta; Linkage Disequilibrium; Mice; Mice, Inbred Strains; Mice, Knockout; Microsatellite Repeats; Orthodontics, Corrective; Osteoprotegerin; Receptor Activator of Nuclear Factor-kappa B; Receptors, Purinergic P2; Receptors, Purinergic P2X7; Root Resorption; Tooth Apex

Odontoclastic root resorption is a significant clinical issue in relation to orthodontic tooth movement, and resorption of the roots of primary teeth is an intriguing biological phenomenon. The functional coordination of the OPG/RANKL/RANK system seems to contribute not only to alveolar remodeling, but also to resorption during orthodontic tooth movement and physiological root resorption. Serum OPG and s-RANKL are related to regulation of bone homeostasis by the OPG/RANKL/RANK system, and determination of their concentrations might be useful for predicting the rate of bone remodeling during orthodontic tooth movement, the net effect between bone remodeling and root resorption, and the degree of root resorption. It is therefore rational to speculate that a study of the levels of OPG and s-RANKL in blood and GCF, in relation to the degree of root resorption during orthodontic tooth movement, using healthy experimental animals and a carefully planned and organized experimental design, may be able to answer this intriguing question.

Topics: Animals; Bone Remodeling; Homeostasis; Osteoclasts; Osteoprotegerin; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Root Resorption; Tooth Movement Techniques

Root resorption is a physiologic event for the primary teeth. It is still unclear whether odontoclasts, the cells which resorb the dental hard tissue, are different from the osteoclasts, the cells that resorb bone. Root resorption seems to be initiated and regulated by the stellate reticulum and the dental follicle of the underlying permanent tooth via the secretion of stimulatory molecules, i.e. cytokines and transcription factors. The primary root resorption process is regulated in a manner similar to bone remodeling, involving the same receptor ligand system known as RANK/RANKL (receptor activator of nuclear factor-kappa B/ RANK Ligand). Primary teeth without a permanent successor eventually exfoliate as well, but our current understanding on the underlying mechanism is slim. The literature is also vague on how resorption of the pulp and periodontal ligament of the primary teeth occurs. Knowledge on the mechanisms involved in the physiologic root resorption process may enable us to delay or even inhibit exfoliation of primary teeth in those cases that the permanent successor teeth are not present and thus preservation of the primary teeth is desirable.

Topics: Dental Sac; Humans; Osteoclasts; Osteoprotegerin; Parathyroid Hormone-Related Protein; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Root Resorption; Tooth Eruption; Tooth, Deciduous

External root resorption is one of common complications of orthodontic treatment, while internal root resorption is rarely observed, and the difference between pulp and periodontal tissues during orthodontic treatment is still unknown. The purpose of this study was to evaluate the effects of orthodontic forces on histological and cellular changes of the dental pulp and periodontal tissues.. Orthodontic tooth movement model was established in Forty-eight adult male Wistar rats. The distance of orthodontic tooth movement was quantitatively analyzed. The histological changes of pulp and periodontal tissues were performed by hematoxylin-eosin staining, tartrate-resistant acid phosphate staining was used to analyze the changes of osteoclast number, immunohistochemistry analysis and reverse transcription polymerase chain reaction were used to examine the receptor of nuclear factor-κB ligand (RANKL) and osteoprotegerin (OPG) expression. The width of tertiary dentine was quantitatively analyzed. Tartrate-resistant acid phosphate staining and the erosion area of osteo assay surface plate was used to evaluate osteoclast activity.. The orthodontic tooth movement distance increased in a force dependent manner, and reached the peak value when orthodontic force is 60 g. Heavy orthodontic force increased the RANKL expression of periodontal ligament srem cells (PDLSCs) which further activated osteoclasts and resulted in external root resorption, while the RANKL expression of dental pulp stem cells (DPSCs) was relatively low to activate osteoclasts and result in internal root resorption, and the dental pulp tend to form tertiary dentine under orthodontic force stimulation.. Heavy orthodontic forces activated osteoclasts and triggered external root resorption by upregulating RANKL expression in rat periodontal tissues, while there was no significant change of RANKL expression in dental pulp tissue under heavy orthodontic forces, which prevented osteoclast activation and internal root resorption.

Topics: Animals; Male; Osteoclasts; Osteoprotegerin; Periodontal Ligament; Phosphates; RANK Ligand; Rats; Rats, Wistar; Root Resorption; Tartrates; Tooth Movement Techniques

To explore the effect of healthy human periodontal ligament fibroblasts (hPDLFs) -derived exosomes on tooth resorption after delayed tooth replantation in rats and its possible mechanism.. The exosomes derived from hPDLFs were isolated and identified in thirty six-week-old SD rats and randomly divided into control group and exosome group. The right maxillary first molar was extracted to establish a delayed tooth replantation model. The dislocated teeth were implanted back into the alveolar fossa after 30 minutes. 40 μL Hanks' balanced salt solution (HBSS) were injected into the periodontal tissue, and the experimental group was injected with 40 μL HBSS containing exosomes. The rats were sacrificed at 1, 2, and 4 weeks. Hematoxylin-eosin (H-E) staining was used to observe tooth resorption. Tartrate-resistant acid phosphatase(TRAP) staining was used to observe the number of osteoclasts. The expression of osteoprotegerin(OPG) in periodontal ligament was detected by immunohistochemical staining. The differences in distribution of each genotype were analyzed with SPSS 17.0 software package.. The identification experiment showed that extracellular vesicles were exosomes. hPDLFs-derived exosomes inhibited root resorption after delayed tooth replantation, reduced the expression of TRAP-positive osteoclasts (P＜0.05), and promoted expression of OPG in periodontal ligament (P＜0.05).. After delayed tooth replantation, PDLFs-derived exosomes reduce the number of osteoclasts, promote OPG expression in the periodontal ligament, and reduce tooth root resorption after replantation.

Topics: Animals; Eosine Yellowish-(YS); Exosomes; Fibroblasts; Hematoxylin; Humans; Osteoprotegerin; Periodontal Ligament; Rats; Rats, Sprague-Dawley; Root Resorption; Tartrate-Resistant Acid Phosphatase; Tooth Replantation; Tooth Root

The understanding of the biological mechanisms involved in root resorption in deciduous teeth is important to the future development of preventive measures and treatments of this condition. The aim of the present study was to compare the expression and immunostaining of iNOS, MMP-9, OPG and RANKL in the periodontal ligament (PDL) of deciduous teeth with physiologic root resorption (GI), inflammatory pathological root resorption (GII) and permanent teeth (GIII), the negative control. Teeth in GI (n = 10), GII (n = 10) and (GIII) (n = 10) were submitted to immunohistochemical analysis to determine the expression of iNOS, MMP-9, OPG, and RANKL. The immunostaining was analysed by optical density. Statistical analysis included one-way ANOVA, followed by Student-Newman-Keuls post hoc test (p < 0.05). The results showed that iNOS, MMP-9 and RANKL expression in the PDL was higher in GII compared to GI and GIII (p < 0.05). Moreover, RANKL expression was higher in GI compared to GIII (p < 0.001), while OPG immunolabelling was lower in GII compared to GI and GIII (p < 0.001). The PDL of deciduous teeth bearing inflammatory processed exhibited upregulation of resorption-associated factors as well as enzymes related to tissue degradation which, in turn explains the exacerbation and greater susceptibility of those teeth to root resorption process.

Topics: Humans; Inflammation; Matrix Metalloproteinase 9; Osteoprotegerin; Periodontal Ligament; RANK Ligand; Root Resorption; Tooth, Deciduous

Root resorption is a side effect of orthodontic tooth movement (OTM). Despite the recognized role of estrogen on bone, there is little information about their effects on orthodontic-induced inflammatory root resorption (OIIRR). We aimed to investigate if estrogen deficiency affects OIIRR in two mice strains.. Female Balb/C (Balb) and C57BL6/J (C57) mice were ovariectomized (OVX) and replaced with estradiol (E2). Tooth samples subjected or not to OTM were collected and analyzed by microCT, histomorphometry and qPCR.. OVX resulted in decreased root volume (RV/TV) and root mineral density (RMD) in Balb mice without OTM. In contrast, OVX did not modify physiological root structure of C57 mice. OTM and OIIRR were increased after OVX in both mice strains after 30 days. E2 replacement reversed this phenotype in Balb, but not in C57 mice. Due to the significant increase of OIIRR in OVX Balb mice, the expression of key molecules was investigated in periodontium. Accordingly, these mice showed increased expression of receptor activator of nuclear factor kappa-B ligand (RANKL), tumor necrosis factor alpha, matrix metalloproteinases-2 and -13 and decreased osteoprotegerin (OPG) and interleukin-10 expression after OTM. E2 replacement reversed the changes of these markers.. The lack of estrogen in Balb mice without OTM triggered loss of root structure which was positively correlated to RANKL/OPG ratio. Regardless of mouse strain, the absence of estrogen following OTM induced OIIRR. Mechanisms involve the imbalance of RANKL/OPG system, inflammatory and osteoclastic makers.

Topics: Animals; Estrogens; Female; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Osteoclasts; Osteoprotegerin; Ovariectomy; Periodontal Ligament; RANK Ligand; Root Resorption; Tooth Movement Techniques

The aim of this study was to investigate the association of clinical variables and polymorphisms in the RANKL, RANK, and OPG genes with external apical root resorption (EARR).. The sample was composed of 338 unrelated patients of both sexes, average age 14.9 years (range 8-21) with Class II Division 1 malocclusion, orthodontically treated. Periapical radiographs of the maxillary central incisor with the longer root (reference tooth) were taken before treatment and 6 months after starting treatment. DNA was extracted from buccal epithelial cells with the use of 10 mol/L ammonium acetate and 1 mmol/L EDTA. The analysis of 42 polymorphisms in the RANKL, RANK, and OPG genes was performed by means of real-time polymerase chain reaction. Univariate and multivariate analyzes were performed to verify the association of clinical and genetic variables with EARR (P <0.05).. The initial root length and patient age were associated with EARR. Considering the study of polymorphisms of RANKL, no significant association was found of genetic polymorphisms with EARR. For RANK polymorphisms, only rs12455775 was associated with EARR. Regarding OPG polymorphisms, an association of rs3102724, rs2875845, rs1032128, and rs3102728 with EARR was found. After multivariate analysis, the initial root length, rapid maxillary expansion, and rs3102724 of the OPG gene were associated with EARR.. Longer roots of upper central incisors and rapid maxillary expansion, as well as allele A of the rs3102724 polymorphism of the OPG gene, were associated with EARR in the study population.

Topics: Adolescent; Child; Female; Genetic Association Studies; Humans; Male; Malocclusion, Angle Class II; Orthodontics, Corrective; Osteoprotegerin; Polymorphism, Single Nucleotide; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Root Resorption; Tooth Apex; Young Adult

Physiological root resorption of deciduous teeth is a normal phenomenon, however, the potential mechanisms underlying this process remain unclear. This study aimed to investigate ability of stem cells from human exfoliated deciduous teeth (SHED) on promoting the osteoclastic differentiation of osteoclast precursors and clarify mechanisms underlying this process in vitro. SHED and dental pulp stem cells (DPSCs) were obtained from deciduous teeth and healthy permanent teeth. An indirect co-culture system of SHED or DPSCs were used. The osteoclast precursor peripheral blood mononuclear cells (PBMCs) were established. Ability of SHED and DPSCs in promoting osteoclastogenesis was determined using triiodothyronine receptor auxiliary protein (TRAP) staining, real-time real-time PCR (RT-PCR) and western blotting. The effect of inflammation on the pro-osteoclastogenesis ability of SHED was determined using enzyme linked immunosorbent assay (ELISA), RT-PCR and western blotting. The function of the nuclear factor-κB (NF-κB) pathway in promoting the osteoclastogenesis ability of SHED was determined using RT-PCR and western blotting. SHED exhibited an increased ability to promote osteoclastic differentiation. Expression of tumor necrosis factor-α (TNF-α) was significantly higher in SHED than in DPSCs. Expression of cathepsin K (CTSK), TRAP, and receptor-activator of nuclear-factor-κ B ligand (RANKL), RANKL/osteoprotegerin (OPG) ratio, and expression of cytoplasmic phosphorylated inhibitor of NF-κB α (p-IκBα) and nuclear p65 were markedly up-regulated in SHED post the TNF-α treatment but decreased following NF-κB inhibition. In conclusion, inflammatory cytokine TNF-α appeared to activate NF-κB pathway to up-regulate expression of NF-κB, enhancing ability of SHED in promoting osteoclastogenesis via regulating RANKL/OPG expression.

Topics: Adolescent; Adult; Cathepsin K; Cell Differentiation; Child; Coculture Techniques; Cytokines; Female; Humans; Leukocytes, Mononuclear; Male; Osteoclasts; Osteogenesis; Osteoprotegerin; RANK Ligand; Root Resorption; Stem Cells; Tooth, Deciduous; Tumor Necrosis Factor-alpha; Young Adult

The aim of this study was to evaluate the effects of photobiomodulation on the repair of induced root resorption (RR) after orthodontic tooth movement. Twenty male rats were used in this study. Forty right and left upper first molars were evaluated and divided into four groups (n = 10): negative control group (NC), no tooth movement or irradiation; positive control group (PC), induced tooth movement and root resorption; conventional treatment group (CT), force was removed after 7 days; and photobiomodulation group (PBM) after force removal molars were irradiated every 48 h for 7 days using GaAlAs diode laser (810 nm). Energy per point was 1.5 J (100 mW, 15 s, 75 J cm

Topics: Animals; Low-Level Light Therapy; Male; Osteoprotegerin; RANK Ligand; Rats; Rats, Wistar; Root Resorption; Tooth Movement Techniques

While different levels of root resorption may occur in orthodontic treatment, several preventive approaches have been reported. Nevertheless, little is known about the effect of enamel matrix derivative (EMD) on root repair during orthodontic tooth movement.. To evaluate the effect of EMD on root resorption repair following the application of orthodontic force.. A force of 100 g was exerted for 14 days on the left maxillary first molars of twenty 10-week-old Sprague-Dawley rats divided into the EMD and control groups (n = 10 per group). In the EMD group, repeatedly injection of Emdogain® was administered after the appliance was removed, while phosphate-buffered saline was administered in the control group. In vivo microcomputed tomography (CT), haematoxylin and eosin (H&E) staining, and immunohistochemistry were then used to evaluate the effect of EMD on the process of root repair.. In the EMD group, the observed decrease in root resorption crater volume and increase in both the bone volume fraction and trabecular thickness were significantly greater than those in the control group. H&E staining showed that the periodontal fibres were relatively regular in arrangement and that the surface of the cementum was smooth in the EMD group. Immunohistochemical analysis showed higher bone morphogenetic protein 2 (BMP-2) and bone sialoprotein (BSP) expression levels in the EMD group than in the control group. In addition, the osteoprotegerin (OPG) and receptor activator of NF-κB ligand (RANKL) expression levels were similar in both groups.. EMD enhanced the repair process following orthodontically induced root resorption in rats.

Topics: Animals; Bone Morphogenetic Proteins; Cell Count; Dental Enamel Proteins; Integrin-Binding Sialoprotein; Male; Molar; Orthodontics, Corrective; Osteoclasts; Osteoprotegerin; RANK Ligand; Rats; Rats, Sprague-Dawley; Root Resorption; Tooth Movement Techniques

Epithelial rests of Malassez (ERM), the only odontogenic epithelial structures in periodontal tissue, are proposed to correlate with root resorption, but the detailed mechanism remains unclear. Osteoprotegerin (OPG), the main inhibitor of osteoclastogenesis, plays a pivotal role in inhibiting root resorption, and ERM cells express OPG mRNA in vitro. Thus, in this study, we aimed to clarify OPG expression in ERM in vivo and to explore the role of OPG in ERM to determine whether ERM are associated with root resorption via OPG. We established Opg-knockout (Opg-KO) mice and detected the OPG expression in ERM by immunohistochemical staining in 4-, 6-, 10-, 26- and 52-week-old mice. The ERM of wild-type (WT) mice and Opg-KO mice were evaluated histologically at 4, 10 and 26 weeks of age. Orthodontic root resorption models were established, maxillae were collected after 4 weeks, and ERM were analysed by histomorphometric analysis. In our study, OPG displayed sustained expression in ERM, and OPG deficiency caused the destruction of ERM, characterized by irregular morphology and reduced numbers. Moreover, after orthodontic treatment, the loss of OPG severely damaged ERM, aggravating root resorption. Together, our results demonstrated that ERM expressed the OPG protein in vivo and that OPG deficiency resulted in morphological and quantitative damage to ERM. Furthermore, ERM may be associated with root resorption via OPG, thus helping to explain the mechanism underlying root resorption.

Topics: Animals; Epithelial Cells; Mice; Mice, Knockout; Osteoprotegerin; Periodontium; Root Resorption; Tooth Migration; Tooth Root

To evaluate the expression of TNF-α, IL-6, IFN-γ, TGF-β, IL-4, IL-10, RANKL, RANK and OPG on mouse calvarial bone treated with MTA, Geristore. Bone wounds were made on the heads of C57BL/6 mice, breaking the periosteum and the cortical surface of the calvaria. Each repair agent was inserted into sectioned Eppendorf microtubes and placed on the bone wound, and soft tissues were sutured. At 14 and 21 days, animals were sacrificed and the treated region was dissected. The calvaria bone was removed, and RNA was extracted. mRNA expression of the aforementioned cytokines was assessed using real-time PCR. Data were analysed by nonparametric methods, including the Mann-Whitney and Kruskal-Wallis tests (P < 0.05).. Following treatment with Emdogain. The clinical indication of these repair agents depends on the root resorption diagnosis. Whilst MTA and Emdogain

Topics: Aluminum Compounds; Animals; Calcium Compounds; Cytokines; Dental Enamel Proteins; Drug Combinations; Gene Expression Regulation; Glass Ionomer Cements; Inflammation; Interferon-gamma; Interleukin-10; Interleukin-4; Interleukin-6; Mice; Mice, Inbred C57BL; Osteoprotegerin; Oxides; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Resins, Synthetic; RNA, Messenger; Root Resorption; Silicates; Transforming Growth Factor beta; Tumor Necrosis Factor-alpha

The physiological root resorption of deciduous teeth is a normal phenomenon, but the mechanisms underlying this process are still unclear. In this study, deciduous dental pulp stem cells (DDPSCs) and permanent dental pulp stem cells (DPSCs) were derived from deciduous teeth and normal permanent teeth at different stages of resorption. In the middle stage of root resorption, DDPSCs exhibited an increase in the ability to induce osteoclast differentiation. Activation of the alpha 7 nicotinic acetylcholine receptor (α7 nAChR) by secretory mammalian Ly-6 urokinase-type plasminogen activator receptor-associated protein 1 (SLURP-1) caused a significant increase in the expression levels of NF-κB, receptor activator of nuclear factor-kappa B ligand (RANKL), and the ratio of RANKL/osteoprotegerin (OPG). These effects were inhibited by alpha-bungarotoxin (α-BTX). Furthermore, the expression levels of RANKL/OPG were significantly reduced following inhibition of NF-κB. High-strength, dynamic positive pressure increased the expression of SLURP-1 and α7 nAChR in DDPSCs in the stable stage. These data indicated that mechanical stress stimulated the expression of SLURP-1 and α7 nAChR in DDPSCs. Additionally, SLURP-1 activated α7 nAChR, thereby upregulating the expression of NF-κB and enhancing its activity, thus regulating RANKL/OPG expression and affecting the ability of DDPSCs to influence osteoclastogenesis, which likely enhances root resorption and leads to the physiological loss of deciduous teeth.

Topics: Adult Stem Cells; alpha7 Nicotinic Acetylcholine Receptor; Animals; Antigens, Ly; Cell Line; Cells, Cultured; Child; Dental Pulp; Humans; Mice; NF-kappa B; Osteoclasts; Osteogenesis; Osteoprotegerin; RANK Ligand; Root Resorption; Tooth, Deciduous; Urokinase-Type Plasminogen Activator

To immunohistochemically investigate the longitudinal changes in root resorption by jiggling force in experimental animal models.. Fifty-six 12-week-old male Wistar rats were used. The maxillary first molars were alternately moved in the buccal and lingual direction in 28 rats (experimental group) using an experimental appliance to produce jiggling forces of 10 g. In another 28 rats (control group), the maxillary first molars were moved in only the lingual direction with a force of 10 g. After 1, 3, 7, 10, 14, 17, and 21 days, the maxillae were resected and subjected to immunohistochemical analysis. The resorption area was quantified histomorphometrically and the number of odontoclasts on the root surface was counted. Expression of RANKL and OPG was also examined by immunohistochemical staining.. The root resorption area and the number of odontoclasts were significantly greater in the experimental group than in controls. Odontoclasts were detected in the resorption lacunae and PDL in the experimental group, whereas osteoclasts were located only along the alveolar bone in controls. OPG was detected on the alveolar bone in the experimental group and on the root surfaces of the controls.. Jiggling force is a critical factor in severe root resorption, affecting RANKL and OPG expression, which accelerates and inhibits odontoclastic induction, respectively.

Topics: Animals; Biomechanical Phenomena; Immunohistochemistry; Male; Maxilla; Models, Animal; Molar; Orthodontic Wires; Osteoclasts; Osteoprotegerin; RANK Ligand; Rats; Rats, Wistar; Root Resorption; Stress, Mechanical; Time Factors; Tooth Movement Techniques; Tooth Root

Genes, involved in the modulation of inflammatory response and bone remodeling, play a role in the development of postorthodontic external apical root resorption (EARR). The aim of our study was to analyze possible associations between seven single nucleotide polymorphisms (SNPs) in interleukin-17A (IL-17), osteopontin (SPP1), purinoreceptor P2X7 (P2RX7), and tumor necrosis factor receptor superfamily member 11B (TNFRSF11B) genes and EARR in children after orthodontic treatment.. This case-control study comprised 99 orthodontically treated patients (69 controls and 30 subjects with EARR). Genotype determinations of rs2275913, rs11730582, rs9138, rs208294, rs1718119, rs3102735, and rs2073618 were based on polymerase chain reaction using 5' nuclease TaqMan. While no significant differences were observed in allele or genotype frequencies of all seven studied SNPs, specific haplotype of P2RX7 (rs208294 and rs1718119) modified the risk of EARR development (P < 0.05). In addition, the length of treatment with a fixed orthodontic appliance positively correlated with the presence of EARR (P < 0.05).. Although the effect of individual SNPs studied on the EARR development was not confirmed in the Czech population, complex analysis suggested that variability in the P2RX7 gene and the length of orthodontic treatment may be important factors contributing to the etiopathogenesis of postorthodontic EARR.

Topics: Adolescent; Case-Control Studies; Czech Republic; Female; Gene Frequency; Genetic Predisposition to Disease; Humans; Interleukin-17; Male; Orthodontics, Corrective; Osteopontin; Osteoprotegerin; Polymorphism, Single Nucleotide; Receptors, Purinergic P2X7; Root Resorption

The aim of this study is to evaluate and compare therapeutic effects of mesenchymal stem cell (MSCs) and osteoprotegerin (OPG) gene transfer applications on inhibition and/or repair of orthodontically induced inflammatory root resorption (OIIRR).. Thirty Wistar rats were divided into four groups as untreated group (negative control), treated with orthodontic appliance group (positive control), MSCs injection group, and OPG transfected MSCs [gene therapy (GT) group]. About 100g of orthodontic force was applied to upper first molar teeth of rats for 14 days. MSCs and transfected MSC injections were performed at 1st, 6th, and 11th days to the MSC and GT group rats. At the end of experiment, upper first molar teeth were prepared for genetical, scanning electron microscopy (SEM), fluorescent microscopy, and haematoxylin eosin-tartrate resistant acid phosphatase staining histological analyses. Number of total cells, number of osteoclastic cells, number of resorption lacunae, resorption area ratio, SEM resorption ratio, OPG, RANKL, Cox-2 gene expression levels at the periodontal ligament (PDL) were calculated. Paired t-test, Kruskal-Wallis, and chi-square tests were performed.. Transferred MSCs showed marked fluorescence in PDL. The results revealed that number of osteoclastic cells, resorption lacunae, resorption area ratio, RANKL, and Cox-2 were reduced after single MSC injections significantly (P < 0.05). GT group showed the lowest number of osteoclastic cells (P < 0.01), number of resorption lacunae, resorption area ratio, and highest OPG expression (P < 0.001).. Taken together all these results, MSCs and GT showed marked inhibition and/or repair effects on OIIRR during orthodontic treatment on rats.

Topics: Animals; Bone Resorption; Gene Transfer Techniques; Genetic Therapy; Male; Mesenchymal Stem Cell Transplantation; Microscopy, Electron; Molar; Osteoclasts; Osteoprotegerin; Periodontal Ligament; Rats; Rats, Wistar; Root Resorption; Tooth Movement Techniques

This study aimed to evaluate the effects of White MTA (WMTA) and MTA Fillapex(®) on root resorption, when used for root canal filling, in a rat model of delayed tooth replantation, with special focus on the RANKL/RANK/OPG system. Maxillary right central incisors of male rats were extracted (total N = 48), and exposed to dry environment for 30 min. The animals were allocated into four groups: (1) WMTA; (2) MTA Fillapex; (3) Calcium hydroxide; (4) Negative control. After periodontal ligament removal, root canals were filled with the corresponding material and replanted. After 10 and 60 days, qualitative and semi-quantitative histological and immunohistochemical analyses were carried out. Analysis of variance (ANOVA) with Tukey's post hoc adjustment was used, at 10 and 60 days, to compare the experimental groups in terms of the inflammatory scores and in terms of the changes in OPG, RANK and RANKL. Both WMTA and MTA Fillapex groups displayed inflammatory and replacement resorption, with the presence of dento-alveolar ankylosis, similarly to that observed for calcium hydroxide, in either 10 or 60 days. Notably, a slight increase of the inflammatory process was observed in both MTA groups. Quantitatively, inflammation score analysis showed a significant difference between the calcium hydroxide and the control group at 10 days. On 60 days, dento-alveolar ankylosis was found significantly increased in the MTA Fillapex, in comparison to the control group (p < 0.05). For immunohistochemical analysis, the expression of both RANK and RANKL was reduced in calcium hydroxide and WMTA groups, from 10 to 60 days of evaluation, an effect that was accompanied by increased OPG immunolabelling. Otherwise, the MTA Fillapex group presented a general increase of RANKL immunopositivity, similarly to that observed in the negative control group. Our data showed that none of tested materials was able to fully prevent the root resorption, although the white MTA cement presented an outcome comparable to that seen for calcium hydroxide. MTA cements might present some advantages when considering no need of frequent changes, although the effects of MTA cements in dental avulsion still require further investigation.

Topics: Animals; Calcium Hydroxide; Drug Combinations; Male; Osteoprotegerin; RANK Ligand; Rats; Receptor Activator of Nuclear Factor-kappa B; Root Canal Filling Materials; Root Canal Obturation; Root Resorption; Tooth Replantation

To carry out an immunoassay analysis of biomarkers expressed in gingival crevicular fluid (GCF) with the main goal of finding a useful diagnostic pattern to distinguish between resorbing deciduous teeth and nonresorbing controls.. A split-mouth design was used in this study with a total of 22 GCF samples collected from 11 patients in the mixed dentition. For each child, one deciduous molar with radiographic evidence of root resorption was used as the test tooth whereas the contralateral first permanent molar with formed roots was used as the control tooth. Samples were processed with immunoassays using a panel of selected biomarkers including interleukin-1 beta (IL-1b), interleukin-1 receptor antagonist (IL-1RA), nuclear factor kappa B ligand (RANKL), osteoprotegerin (OPG), matrix metalloproteinase-9 (MMP-9), and dentin sialoprotein (DSP).. There were no statistically significant differences in levels of IL-1b, OPG, and MMP-9 between test and control sites (P > .05). IL-1RA was the only biomarker to show a significant down-regulation (P  =  .04) in GCF samples collected from resorbing teeth. RANKL data showed a heavily skewed distribution and was deemed unreliable. Only one deciduous GCF sample had detectable levels of DSP; therefore, no further statistical calculation was applicable because of the limited amount of data for this biomarker.. This study indicated that IL1-RA is down-regulated in GCF from resorbing primary molars, thus suggesting this cytokine as a potential analyte to be included in a panel that can discriminate between resorbing and nonresorbing teeth.

Topics: Biomarkers; Child; Extracellular Matrix Proteins; Gingival Crevicular Fluid; Humans; Immunoassay; Interleukin 1 Receptor Antagonist Protein; Interleukin-1beta; Matrix Metalloproteinase 9; Molar; Osteoprotegerin; Phosphoproteins; RANK Ligand; Root Resorption; Sialoglycoproteins

Recent studies indicate that the osteoprotegerin (OPG)/RANKL/RANK pathway takes part in root resorption. However, the relationship between OPG and root resorption is vague. The purpose of our study was to investigate the role of OPG in root resorption.. The first molars of the mandibles of osteoprotegerin-knockout (Opg-KO) mice and wild-type (WT) mice were evaluated by micro-computed tomography, histology, and immunohistochemistry at 4, 6, 26, and 52 weeks. To detect the activity of the osteoclasts, we induced bone marrow macrophages into osteoclast-like cells from Opg-KO mice and wild-type mice in vitro and then compared their osteoclast activities. To evaluate the cementum quality, an osteoclast-cementum co-culture model was established in vitro.. In Opg-KO mice, root resorption began at the age of 4 weeks. At 6 weeks the cementum damage extended to the coronal and apical regions, and at 52 weeks the damage reached the predentin. At all observed stages, more tartrate-resistant acid phosphatase (TRAP)-positive cells were found on the surface of cementum in Opg-KO mice. In vitro, the mRNA levels of cathepsin K, TRAP, matrix metalloproteinase-9, and matrix metalloproteinase-1, as well as the protein expression of nuclear factor of activated T cell 1 and TRAP, increased significantly in osteoclast-like cells from Opg-KO mice. In addition, the cementum resorption pits of Opg-KO mice were larger when co-cultured with osteoclast-like cells.. Our study demonstrated that loss of OPG led to root resorption via increasing activation of osteoclasts and reducing mineralization of cementum.

Topics: Animals; Dental Cementum; Macrophages; Mandible; Mice; Mice, Inbred C57BL; Mice, Knockout; Molar; Osteoclasts; Osteoprotegerin; Receptor Activator of Nuclear Factor-kappa B; Root Resorption

The present study was performed to examine how transforming growth factor β (TGF-β) in root-surrounding tissues on deciduous teeth regulates the differentiation induction into odontoclasts during physiological root resorption. We prepared root-surrounding tissues with (R) or without (N) physiological root resorption scraped off at three regions (R1-R3 or N1-N3) from the cervical area to the apical area of the tooth and measured both TGF-β and the tartrate-resistant acid phosphatase (TRAP) activities. The TGF-β activity level was increased in N1-N3, whereas the TRAP activity was increased in R2 and R3. In vitro experiments for the receptor activator of nuclear factor-κB (NF-κB) ligand (RANKL)-mediated osteoclast differentiation revealed that proteins from N1-N3 and R1-R3 enhanced the TRAP activity in RAW264 cells. A genetic study indicated that the mRNA levels of TGF-β1 in N1 and N2 were significantly increased, and corresponded with levels of osteoprotegerin (OPG). In contrast, the expression level of RANKL was increased in R2 and R3. Our findings suggest that TGF-β is closely related to the regulation of OPG induction and RANKL-mediated odontoclast differentiation depending on the timing of RANKL and OPG mRNA expression in the root-surrounding tissues of deciduous teeth during physiological root resorption.

Topics: Animals; NF-kappa B; Osteoclasts; Osteoprotegerin; RANK Ligand; Root Resorption; Swine; Tartrate-Resistant Acid Phosphatase; Tooth, Deciduous; Transforming Growth Factor beta

To investigate the effects of growth hormone (GH) on local receptor activator of nuclear factor-kappa ligand (RANKL), OPG, and IGF-I expression during orthodontically induced inflammatory root resorption in rats.. Forty Wistar rats (gender: male; age: 7 weeks) were randomly divided into control and experimental groups. A force of 50 g was applied to move the right upper first molars mesially. The experimental and control groups received daily subcutaneous injections of recombinant human growth hormone (GH; 2 mg/kg) and equivalent volumes of saline, respectively. The rats were sacrificed on days 1, 3, 7, and 14. Micro-computed tomography-reconstructed images of the upper right first molars were used to survey root resorption and tooth movement. Horizontal sections of the maxillae were prepared for hematoxylin and eosin, tartrate-resistant acid phosphatase, and immunohistochemical staining.. Resorption lacunae appeared on the compressed side of the distal buccal root of the right first molar on days 7 and 14. Compared with the control groups, GH-treated groups showed more RANKL-positive cells and osteoclasts on day 3 and more OPG- and IGF-I-positive cells and fewer odontoclasts on days 7 and 14. Indexes of root resorption were lower and tooth movement was faster in the GH-treated groups than in the control groups on days 7 and 14.. The inhibitory effect of GH on root resorption by heavy force might be mediated by RANKL/OPG and IGF-I. Short-term GH administration may be a method with which to reduce root resorption and shorten treatment time, especially in patients who are susceptible to root resorption.

Topics: Animals; Cell Count; Disease Models, Animal; Human Growth Hormone; Humans; Image Processing, Computer-Assisted; Insulin-Like Growth Factor I; Male; Molar; Osteoclasts; Osteoprotegerin; Periodontal Ligament; Random Allocation; RANK Ligand; Rats; Rats, Wistar; Recombinant Proteins; Root Resorption; Tartrate-Resistant Acid Phosphatase; Time Factors; Tooth Movement Techniques; X-Ray Microtomography

The aim of this study was to evaluate the preventive and/or reparative effects of low-level laser therapy (LLLT) on orthodontically induced inflammatory root resorption (OIIRR) in rats. Thirty rats were divided into four groups (short-term control (SC), short-term laser (SL), long-term control (LC), long-term laser (LL)). In all groups, the left first molar was moved mesially for 11 days. At the end of this period, the rats in groups SC and SL were killed in order to observe the resorption lacunas and to evaluate whether LLLT had any positive effect on root resorption. The groups LC and LL were remained for a healing period of 14 days in order to observe spontaneous repair of the resorption areas and investigate whether LLLT had reparative effects on root resorption. A Ga-Al-As diode laser (Doris, CTL-1106MX, Warsaw, Poland) with a wavelength of 820 nm was used. In SL group, the first molars were irradiated with the dose of 4.8 J/cm2 (50 mW, 12 s, 0.6 J) on every other day during force application. In LL group, the irradiation period was started on the day of appliance removal and the first molars were irradiated with the dose of 4.8 J/cm2 on every other day for the next 14 days. LLLT significantly increased the number of osteoblasts and fibroblasts, and inflammatory response in SL group in comparison with SC group (P = .001). The amount of resorption did not represent any difference between the two groups (P = .16). In LL group, LLLT significantly increased the number of fibroblasts and decreased the amount of resorption in comparison with LC group (P = .001; P = .02). Both parameters indicating the reparative and the resorptive processes were found to be increased by LLLT applied during orthodontic force load. LLLT applied after termination of the orthodontic force significantly alleyed resorption and enhanced/accelerated the healing of OIIRR. LLLT has significant reparative effects on OIIRR while it is not possible to say that it definitely has a preventive effect.

Topics: Animals; Cell Count; Immunohistochemistry; Low-Level Light Therapy; Male; Orthodontics; Osteoclasts; Osteoprotegerin; RANK Ligand; Rats, Wistar; Root Resorption; Time Factors

The objectives of this study were (1) to investigate the expressions of interleukin (IL)-17, RANKL (the receptor activator of NF-kappaB ligand), and osteoprotegerin (OPG) in root resorption areas during experimental tooth movement in rats, and (2) to determine the effect of IL-17 on the expressions of RANKL and OPG mRNA from human dental pulp cells.. Twelve male 6-week-old Wistar rats were subjected to an orthodontic force of 50 g to induce a mesially tipping movement of the maxillary first molars for 7 days. The expression levels of tartrate resistant acid phosphatase (TRAP), interleukin (IL)-17, IL-17 receptor (IL-17R), receptor activator of nuclear factor-kappa B ligand (RANKL), and OPG proteins were determined in dental pulp by immunohistochemical analysis. Furthermore, the effects of IL-17 on the expressions of RANKL and OPG mRNA were investigated using human dental pulp cells in vitro.. In the experimental tooth movements in vivo, resorption lacunae with multinucleated cells were observed in the 50-g group. The immunoreactivities for IL-17, IL-17R, and RANKL were detected in dental pulp tissues subjected to the orthodontic force on day 7. Moreover, IL-17 increased the mRNA expression of RANKL from human dental pulp cells in vitro.. The results of this study suggest that IL-17 and RANKL may be involved in the process of orthodontically induced inflammatory root resorption in dental pulp cells.

Topics: Acid Phosphatase; Adolescent; Animals; Cell Culture Techniques; Cells, Cultured; Dental Pulp; Female; Humans; Interleukin-17; Isoenzymes; Male; Osteoclasts; Osteoprotegerin; RANK Ligand; Rats; Rats, Wistar; Receptors, Interleukin-17; Root Resorption; Stress, Mechanical; Tartrate-Resistant Acid Phosphatase; Tooth Movement Techniques

Physiological primary teeth exfoliation is a normal phenomenon during teeth development. However, retained primary teeth can often be observed in the patients with cleidocranial dysplasia (CCD) caused by mutation of Runx2. The potential regulative mechanism is still unknown. In the present study, periodontal ligament stem cells (PDLSCs) were derived from different resorbed stages of primary teeth and permanent teeth from normal patients and primary teeth from CCD patient. The proliferative, osteogenic and osteoclast-inductive capacities of PDLSCs from each group were detected. We demonstrated here that the proliferative ability of PDLSCs was reduced while the osteogenic and the osteoclast-inductive capacity of PDLSCs were enhanced during root resorption. The results also showed that PDLSCs from permanent teeth and CCD patient expressed low level of Runx2 and RANKL while high level of OPG. However, expression of Runx2 and RANKL were increased while expression of OPG was decreased in PDLSCs derived from resorbed teeth. Furthermore, Runx2 regulating the expression of RANKL and OPG and the osteoclast-inductive capacity of PDLSCs were confirmed by gain or loss of function assay. These data suggest that PDLSCs promote osteoclast differentiation via Runx2 upregulating RANKL and downregulating OPG, leading to enhanced root resorption that results in physiological exfoliation of primary teeth.

Topics: Cells, Cultured; Child; Child, Preschool; Core Binding Factor Alpha 1 Subunit; Female; Gene Expression Regulation; Humans; Male; Osteoclasts; Osteoprotegerin; Periodontal Ligament; RANK Ligand; Root Resorption; Stem Cells; Tooth Exfoliation; Tooth, Deciduous

There are multiple causes of external root resorption, but absent a disease state, it is most often observed when excessive physical force is used during orthodontic treatment. Even without mechanical stimulation, however, root resorption can still occur. The purpose of this study was to test whether Wnt signaling plays a role in pathologic root resorption, by conditionally deleting Wntless (Wls) from odontoblasts and osteoblasts and then evaluating the phenotypic effects on the maintenance of the root surface.. Ten (age, 1 month) and 20 (age, 3 months) OCN-Cre;Wls(fl/fl) mice and their wild-type littermates were evaluated using microcomputed tomography, histology, and immunohistochemistry. Phenotypic alterations in the alveolar bone, dentin, and cementum were characterized and quantified.. In a genetic model of reduced Wnt signaling, we found that RANKL expression is upregulated, and osteoprotegerin expression is downregulated. This molecular disruption results in an increase in osteoclast activity, a decrease in osteoblast activity, and extensive, spontaneous root resorption. A genetic strain of mice in which Wnt signaling is elevated exhibits thicker cementum, whereas, even in the perinatal period, OCN-Cre;Wls(fl/fl) mice exhibit thinner cementum.. Taken together, these data demonstrate that Wnts regulate cementum homeostasis, and that idiopathic cases of root resorption might have as their etiology a reduction in endogenous Wnt signaling.

Topics: Acid Phosphatase; Age Factors; Alkaline Phosphatase; Alveolar Process; Animals; Axin Protein; Dental Cementum; Dentin; Down-Regulation; Extracellular Matrix Proteins; Immunohistochemistry; Isoenzymes; Mice; Mice, Inbred Strains; Odontoblasts; Osteoblasts; Osteoprotegerin; Phenotype; Phosphoproteins; RANK Ligand; Root Resorption; Sialoglycoproteins; Tartrate-Resistant Acid Phosphatase; Tooth Cervix; Up-Regulation; Wnt Proteins; Wnt Signaling Pathway; X-Ray Microtomography

To investigate and compare the expression of the pathogen recognition receptors Toll-like receptor (TLR) 2 and TLR4, and the hard tissue resorption triad osteoprotegerin (OPG)-receptor activator of nuclear factor kappa-B ligand (RANKL)-receptor activator of nuclear factor kappa-B (RANK) in external inflammatory root resorption of endodontic origin (ER) and external cervical root resorption (ECR) by immunohistochemistry.. Formalin-fixed, paraffin-embedded archival specimens collected from teeth that were diagnosed clinically, radiographically and histopathologically with either ER (n = 9) or ECR (n = 9) were processed for immunohistochemistry to investigate and compare levels of TLR2, TLR4, OPG, RANKL, RANK, CD3, CD19 and CD83 expression. The histological features were evaluated via haematoxylin and eosin stain. Taylor's modification of the Brown and Brenn Gram stain was used for examining the presence and distribution of bacteria. All stained slides were digitally photographed and qualitatively analysed, and F test and unpaired Student's t-test were used for statistical analysis.. Both ER and ECR showed similar immuno-histopathology characteristics of a fibrovascular connective tissue with varying degrees of inflammatory infiltrate consisting of T and B lymphocytes, dendritic cells, polymorphonuclear lymphocytes and plasma cells. Colonies of bacteria were identified in the majority of lesions, and this correlated with the cellular expression of TLR2 and TLR4 in all lesions. Similarly, all lesions showed a significantly higher (P < 0.05) level of cells expressing RANKL than OPG, indicating hard tissue resorption processes where active in the lesions.. The immunohistopathology patterns of ECR samples were consistent with the bacteria-driven ER specimens, suggesting bacteria-induced inflammation may be involved in ECR.

Topics: Humans; Inflammation; Osteoprotegerin; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Root Resorption; Toll-Like Receptor 2; Toll-Like Receptor 4; Tooth Cervix

Dental tissues have special characteristics, and its regenerative capacity is noteworthy. However, understanding the circumstances that lead to regeneration is challenging. In this study, the chronology of the healing process after immediate replantation of rat incisor teeth was examined by histological and immunohistochemical analyses within a 60-day period. Thirty-six male Wistar rats had their maxillary right incisors extracted and replanted after 15 min in saline storage. The rats were sacrificed immediately 3, 7, 15, 28, and 60 days after replantation. The histological analysis showed rupture of the periodontal ligament and formation of a blood clot, which started being replaced by a connective tissue after 3 days. At 7 days, the gingival mucosa epithelium was reinserted and areas of root resorption could be seen. At 15 days, the periodontal ligament was repaired. At 3 days, the pulp presented an absence of the odontoblast layer, which started being replaced by a connective tissue. This tissue suffered gradual calcification, filling the root canal at 28 and 60 days. The root ends were closed. The immunohistochemical analysis revealed greater expression of OP, OPG, and RANK proteins in the initial periods (0 and 3 days), while TRAP expression predominated at 28 and 60 days (P < 0.05). In conclusion, in delayed tooth replantation, there is great new bone formation activity in the earlier periods of the repair process, while a predominance of bone resorption and remodeling is observed in the more advanced periods.

Topics: Acid Phosphatase; Animals; Biomarkers; Blood Coagulation; Collagen; Connective Tissue; Dental Pulp; Dental Pulp Calcification; Epithelium; Gingiva; Immunohistochemistry; Incisor; Isoenzymes; Male; Odontoblasts; Osteopontin; Osteoprotegerin; Periodontal Ligament; RANK Ligand; Rats; Rats, Wistar; Receptor Activator of Nuclear Factor-kappa B; Root Resorption; Rupture; Tartrate-Resistant Acid Phosphatase; Time Factors; Tooth Apex; Tooth Replantation; Tooth Socket; Wound Healing

The aim of this study was to investigate how atopic dermatitis (AD) contributes to root resorption during orthodontic tooth movement.. Atopic dermatitis model mice and wild-type mice were subjected to an excessive orthodontic force (OF) to induce movement of the upper first molars. The expression levels of the tartrate-resistant acid phosphatase (TRAP), IL-17, IL-6, and RANKL proteins were determined in the periodontal ligament (PDL) by an immunohistochemical analysis. Furthermore, the effects of the compression force on co-cultures of CD4(+) cells from AD patients or healthy individuals and human PDL cells were investigated with regard to the levels of secretion and mRNA expression of IL-17, IL-6, RANKL, and osteoprotegerin.. The immunoreactivities for TRAP, IL-17, IL-6, and RANKL in the AD group were found to be significantly increased. The double immunofluorescence analysis for IL-17/CD4 detected immunoreaction. The secretion of IL-17, IL-6, and RANKL, and the mRNA levels of IL-6 and RANKL in the AD patients were increased compared with those in healthy individuals.. Th17 cells may therefore be associated with the deterioration of root resorption of AD mice, and may explain why AD patients are more susceptible to root resorption than healthy individuals when an excessive OF is applied.

Topics: Acid Phosphatase; Adult; Animals; CD4-Positive T-Lymphocytes; Cell Culture Techniques; Coculture Techniques; Dermatitis, Atopic; Disease Models, Animal; Female; Humans; Immunoglobulin E; Interleukin-17; Interleukin-6; Isoenzymes; Male; Mice; Mice, Inbred BALB C; Osteoprotegerin; Periodontal Ligament; RANK Ligand; Root Resorption; Stress, Mechanical; Tartrate-Resistant Acid Phosphatase; Th17 Cells; Tooth Movement Techniques; Young Adult

External root resorption (ERR) is a serious complication of orthodontic treatment. Aim of this study was to evaluate the effects of local osteoprotegerin (OPG) gene transfection on ERR during retention.. Eighteen 6-week-old male Wistar rats were divided into three groups. All the rats were subjected to 2 weeks of orthodontic tooth movement followed by a 2-week retention period. During retention, the three groups of rats received local OPG gene transfection (OPG transfection group, n=6), mock vector transfection (mock group, n=6), or no injections (control group, n=6). ERR of all three groups was evaluated with in vivo micro-CT analysis at three different time points: baseline, the last day of orthodontic tooth movement, and the last day of retention.. In the OPG transfection group, there was no significant difference between ERR at the baseline and ERR on the last day of retention. By the last day of retention, the repair ratio of ERR in the OPG transfection group was statistically higher in relation to the repair ratio of the other groups (p<0.001).. The results indicated that local OPG gene transfection significantly enhanced the repair of ERR during retention. Local OPG gene transfection might therefore be a useful tool for ERR repair during retention.

Topics: Alveolar Process; Animals; Bone Density; Bone Remodeling; Genetic Therapy; Genetic Vectors; Imaging, Three-Dimensional; Male; Maxilla; Orthodontic Retainers; Orthodontic Wires; Osteoprotegerin; Random Allocation; Rats; Rats, Wistar; Root Resorption; Sendai virus; Tibia; Time Factors; Tooth Movement Techniques; Transfection; X-Ray Microtomography

Icariin has been reported to enhance bone healing and treat osteoporosis. In this study, we examined the effect of Icariin on rapid palatal expansion induced root resorption in rats. Our hypothesis is that Icariin can enhance the healing of rapid palatal expansion induced root resorption. Forty-eight male Wistar rats were divided randomly and equally into three groups (n=16 rats each). The rats were untreated (negative control) or treated with rapid palatal expansion without (positive control) or with Icariin at 2.5 mg/kg day (Icariin-treated groups). An initial force of 50×g was applied to the areas between the right and left upper first molars of the rats for 21 days. Eight rats were randomly chosen from each group, and the root resorption index (RRI) was determined with scanning electron microscopy (SEM). Upper first molar-centered buccal- lingual tissue slices were generated from the upper first molars and peridentium of the remaining eight rats from each group. Specimen slices were analyzed with HE and tararate-resistant acid phosphatase staining, osteoprotegerin (OPG) and receptor activator of nuclear factor kappa-B ligand (RANKL) immunohistochemistry, and optical microscopy. Analyses of cell number, densitometry, and one-way analysis of variance were performed. The Icariin-treated groups displayed decreased RRI values, decreased osteoclast numbers and activity levels, and increased OPG/RANKL expression ratios. High-power SEM revealed reparative cementum in the Icariin-treated samples. Icariin regulates osteoclast differentiation via the OPG/RANKL ratio, evoking a reparative effect on rapid palatal expansion induced root resorption in rats.

Topics: Animals; Bone Resorption; Cell Differentiation; Flavonoids; Male; Osteoclasts; Osteoporosis; Osteoprotegerin; Palatal Expansion Technique; Random Allocation; RANK Ligand; Rats; Rats, Wistar; Root Resorption; Tooth Root

Osteoprotegerin (OPG), as an osteoclast antagonist, limits mineralised tissue resorption under physiological conditions. Previous work investigating OPG in a rat periodontal ligament (PDL) ankylosis model found no inhibitory effect on osteoclasts when OPG was administered at a dosage of 2.5mg/kg.. The object of this study was to determine whether dosages higher than 2.5 mg/kg of OPG were required to limit osteoclastic activity in an aseptic inflammatory model in rats.. Dry ice was applied for 15 minutes to the upper right first molar crown of eighteen, 8-week-old, male Sprague-Dawley rats. Three groups of 3 were injected with OPG at dosages of 2.5, 5.0 and 7.5 mg/kg of body weight immediately following the thermal insult. After 7 days, the rats were sacrificed and each maxilla processed for histological examination and stained for osteoclastic activity using tartrate-resistant acid phosphatase (TRAP). Osteoclast population numbers were estimated via light microscopy and results were analysed using a comparative mixed model statistical analysis.. Results showed OPG inhibited osteoclastic activity in a dose-dependent manner. From 2.5 mg/kg to 7.5 mg/kg, osteoclast populations were linearly reduced by 39.78% (p < 0.05). OPG did not appear to affect the inflammatory process and had varied efficacy in different regions of individual teeth.. Although osteoclastic activity reduced, it was not completely eliminated, perhaps because dosages were still inadequate, or additional factors might influence OPG and osteoclast activation in the aseptic inflammatory model.

Topics: Acid Phosphatase; Animals; Biomarkers; Cell Count; Disease Models, Animal; Dose-Response Relationship, Drug; Dry Ice; Freezing; Inflammation; Isoenzymes; Male; Maxilla; Molar; Necrosis; Odontoblasts; Osteoclasts; Osteoprotegerin; Rats; Rats, Sprague-Dawley; Root Resorption; Tartrate-Resistant Acid Phosphatase; Tooth Crown

Physiological root resorption differentiates primary from permanent teeth. The understanding of what protects and regulates root resorption might help to develop therapies to its control.. To verify the presence and distribution of ECRM and the expression of CK14, OPG, TRAP and COX-2 in the periodontal ligament (PDL) of human primary and permanent teeth. Design.  Eight primary teeth undergoing physiological or pathological root resorption and 4 permanent teeth were immunohistochemically processed for CK14, TRAP, COX-2 and OPG expression.. PDL from primary and permanent teeth showed similar morphological features; however, fewer ECRM clusters and higher immunoreactivity to CK14 were found in primary PDL. In permanent teeth, ECRM were distributed along the entire PDL tissue. Howship's lacunae were found only in primary teeth, associated with the presence of TRAP-positive cells and increase in COX-2 expression. OPG expression in primary PDL was detected in nonresorptive cervical areas and in lacunae showing reparative tissue. It was observed higher expression of OPG in all permanent teeth when compared to primary specimens.. It may be concluded that PDL from primary teeth shows less ECRM clusters and lower expression of OPG. These features may be associated with lower protection against root resorption in primary teeth.

Topics: Acid Phosphatase; Adult; Child; Child, Preschool; Cyclooxygenase 2; Dentition, Permanent; Epithelial Cells; Gene Expression; Humans; Isoenzymes; Keratin-14; Osteoprotegerin; Periodontal Ligament; Root Resorption; Tartrate-Resistant Acid Phosphatase; Tooth, Deciduous; Young Adult

To evaluate the effect of pulsed ultrasound on the expressions of osteoprotegerin (OPG) and receptor activator nuclear factor kappaB ligand (RANKL) during root resorption in a mouse model of orthodontic tooth movement.. Thirty-two male Wistar rats (6-8 weeks old) were randomly assigned into 4 equal groups, including the blank control group, two ultrasound exposure groups with daily local LIPUS stimulation (100 and 150 MW/cm(2)) for 10 days during mechanical loading, and the control group with mechanical loading but not LIPUS exposure. Nickel-titanium closed-coil springs were used to generate 100 g mesial force for 10 days to move the maxillary right first molars. The expression of OPG and RANKL proteins at the compression sites was detected by immunohistochemistry.. Ultrasound stimulation significantly up-regulated the expression of OPG and down-regulated RANKL expression (P<0.05). The expressions of OPG and RANKL showed significant differences between the two ultrasound exposure groups (P<0.05).. Ultrasound stimulation might be useful to protect against root resorption and accelerate its repair by regulating the expressions of OPG and RANKL.

Topics: Animals; Male; Osteoprotegerin; RANK Ligand; Rats; Rats, Wistar; Root Resorption; Ultrasonography, Doppler, Pulsed

It is hypothesised that osteoprotegerin (OPG), as an osteoclast antagonist, may offer molecular control over the process of orthodontic root resorption. Previous work investigating OPG in a rat periodontal ligament (PDL) ankylosis model found no inhibitory effect on osteoclasts and odontoclasts when given at a recommended dosage of 2.5 mg/kg. It was considered that traumatically-induced PDL inflammation produces mediators and cytokines with the ability to stimulate clast cell differentiation and counter the effects of OPG.. The present study investigated the presence of Tumour Necrosis Factor Alpha (TNF-alpha) and its receptor Tumour Necrosis Factor Receptor 1 (TNFR1) in a PDL sterile inflammatory model.. Dry ice was applied for 15 minutes to the upper right first molar crown of eighteen, 8-week-old, male Sprague-Dawley rats of which 9 were injected with OPG at a dose of 2.5 mg/kg of body weight at the time of freezing. After 7 days, the rats were sacrificed and each maxilla processed for immunohistochemical identification of TNF-alpha and TNFR1.. Results showed the presence of root resorption in varying amounts and locations in both experimental and control rats. Reparative processes appeared greater in the OPG-treated rats, often with the presence of an ankylotic union. Immunolabelling showed the presence of TNF-alpha and TNFR1 in the sterile inflammation located mainly in the interradicular PDL area. More definitive labelling appeared in OPG-treated rats.. The results indicated that TNF-alpha, and its receptor TNFR1, by their presence, may modify OPG effectiveness by offering an alternative pathway for osteoclast formation, which counters the anti-resorptive effects of OPG.

Topics: Alveolar Process; Animals; Cold Temperature; Dental Pulp; Dental Pulp Necrosis; Fibroblasts; Giant Cells; Gingiva; Male; Molar; Osteoclasts; Osteoprotegerin; Periodontal Ligament; Random Allocation; Rats; Rats, Sprague-Dawley; Receptors, Tumor Necrosis Factor, Type I; Root Resorption; Tooth Ankylosis; Tumor Necrosis Factor-alpha; Wound Healing

This study examined the histological changes and possible effects of intermittent parathyroid hormone (PTH) (1-34) treatment during the early and late phase of periodontal repair in a rat model of tooth root resorption. In a total of 70 animals, which either received intermittent PTH(1-34) systemically or sham injections for up to 70 days after discontinuation of an orthodontic force, histological characteristics were correlated to time-dependent distinct expression patterns of osteoprotegerin and receptor activator of nuclear factor kappaB ligand by PDL cells in the former compression and tension side of tooth movement by means of immunohistochemistry and histomorphometrical analysis. The balance of these key regulators of bone remodeling was demonstrated to be shifted in favor of hard tissue repair by intermittent PTH administration, which was demonstrated to exert anabolic effects in several cell culture and animal experiments as well as in humans, in the late phase of repair. These data indicate a role for PDL cells as potent regulators of periodontal repair by modifying the local microenvironment and point to the anabolic potential of an intermittent PTH administration to support these reparative processes.

Topics: Animals; Bone Remodeling; Immunohistochemistry; Male; Models, Animal; Osteoprotegerin; Parathyroid Hormone; Periodontal Ligament; RANK Ligand; Rats; Rats, Wistar; Root Resorption; Tooth Movement Techniques

The aim of the present study was the determination of the levels of osteoprotegerin and soluble RANKL in blood serum and in gingival crevicular fluid relative to the degree of orthodontic root resorption in a rat model. Blood samples and gingival crevicular fluid were collected from fourteen 6-month-old male Wistar rats weighing 350-500 g. A 25-g closed orthodontic coil spring was inserted between each upper right first molar and the upper incisors. After 21 days of loading, both upper first molars (treated and control) were extracted and studied under microcomputed tomography scanning. Statistical analysis demonstrated a positive linear correlation between the initial concentration of RANKL in blood serum and the degree of root resorption. The ratio of the initial concentrations of osteoprotegerin to RANKL in blood serum proved to be an independent prognostic factor of the degree of root resorption. The initial concentration of RANKL in gingival crevicular fluid showed a negative correlation to the initial concentration of RANKL in blood serum and for a finite range of initial concentrations of osteoprotegerin in gingival crevicular fluid, the dental root seemed protected against extreme external root resorption. Finally, the concentration of osteoprotegerin in blood serum decreased significantly in cases of severe root resorption.

Topics: Animals; Disease Models, Animal; Gingival Crevicular Fluid; Image Processing, Computer-Assisted; Imaging, Three-Dimensional; Incisor; Male; Molar; Orthodontic Wires; Osteoprotegerin; RANK Ligand; Rats; Rats, Wistar; Root Resorption; Stress, Mechanical; Tooth Movement Techniques; Tooth Root; X-Ray Microtomography

OBJECTIVES - To test the hypothesis that during root resorption, organic matrix proteins and cytokines from the surrounding bone and dentin are released into the gingival crevice. MATERIAL AND METHODS - Subjects with mild (<2 mm loss) and severe root resorption (>2 mm) were identified. Control group subjects with no loss of root structure or undergoing orthodontic treatment were also identified. Gingival crevicular fluid (GCF) was collected non-invasively from the mesial and distal sides of each of the four upper incisors by using filter paper strips. The eluted GCF was used for analysis using western blot and enzyme-linked immunosorbent assay (ELISA) techniques. Antibodies used were against osteopontin (OPN), (osteoprotegerin) OPG, and receptor activator of nuclear factor kappa B ligand (RANKL). RESULTS - Western blot analysis showed differential expression of OPN, OPG, and RANKL in the control and root resorbed subjects. However, processed forms of these proteins were only observed in the root resorbed subjects. Results from ELISA with OPG antibodies revealed a difference in OPG concentration between the control and root resorption groups. ELISA results with RANKL antibodies did show a statistically significant difference between the control group and the two study groups. The ratio RANKL/OPG was statistically higher in subjects with severe root resorption than in the control subjects. CONCLUSIONS - Preliminary results confirm the presence of matrix proteins and cytokines in the GCF of root resorbed subjects. Further, OPG was locally present in excess amounts over RANKL and an increased RANKL/OPG in the study groups could be correlated with an increased bone resorption activity during orthodontic tooth movement.

Topics: Biomarkers; Blotting, Western; Bone and Bones; Cytokines; Dentin; Electrophoresis, Polyacrylamide Gel; Enzyme-Linked Immunosorbent Assay; Gingival Crevicular Fluid; Humans; Incisor; Orthodontics, Corrective; Osteopontin; Osteoprotegerin; Phosphoproteins; Radiography; RANK Ligand; Root Resorption

The aim of this study was to compare the expression of nuclear factor kappaB (RANK), RANK ligand (RANKL), and osteoprotegerin (OPG) in odontogenic epithelial tumors and dentigerous cysts.. The expression of these molecules was evaluated in solid/multicystic ameloblastomas (n = 12) and unicystic ameloblastomas (n = 8), keratocystic odontogenic tumors (n = 19), dentigerous cysts (n = 9), and dental follicles (n = 9) by immunohistochemistry.. In odontogenic epithelium, a similar expression of RANK, RANKL, and OPG was observed in all samples. With regard to stroma, the number of RANK-positive and RANKL-positive cells was higher in solid/multicystic ameloblastomas compared with dentigerous cysts. Dental follicles had lower numbers of RANK-positive, RANKL-positive, and OPG-positive cells than solid/multicystic ameloblastomas and keratocystic odontogenic tumors. The majority of solid/multicystic ameloblastomas (75%) and unicystic ameloblastomas (62.5%) had higher numbers of RANKL-positive than OPG-positive cells. In contrast, 62.4% of keratocystic odontogenic tumors and 100% of dentigerous cysts exhibited a higher content of OPG-positive than RANKL-positive cells.. Our results indicate differences in the RANK, RANKL, and OPG expression in odontogenic epithelial tumors. The imbalance of these factors could contribute to the differential bone/tooth resorption activity in these lesions.

Topics: Ameloblastoma; Cell Count; Dentigerous Cyst; Epithelial Cells; Gene Expression; Humans; Jaw Neoplasms; NF-kappa B; Odontogenic Tumors; Osteolysis; Osteoprotegerin; RANK Ligand; Root Resorption; Statistics, Nonparametric; Stromal Cells

The ligand receptor activator of NFkappaB (RANKL) plays an important role in osteoclast formation. However, very little is known about the relationship between external apical root resorption during orthodontic treatment and RANKL. We hypothesized that compressive force is responsible for RANKL formation and up-regulation of osteoclastogenesis in periodontal ligament (PDL) cells from patients with severe orthodontically induced external apical root resorption. RANKL and osteoprotegerin (OPG) production, TRAP-positive cells, and resorptive pits were determined. The increase of RANKL and the decrease of OPG were greater in the severe root resorption group than in the non-resorption group. The numbers of TRAP-positive cells and resorptive pits were also increased in the severe root resorption group than in the non-resorption group. These results support the hypothesis that the compressed PDL cells obtained from tissues with severe external apical root resorption may produce a large amount of RANKL and up-regulate osteoclastogenesis.

Topics: Adolescent; Adult; Analysis of Variance; Blotting, Western; Carrier Proteins; Case-Control Studies; Cell Differentiation; Cells, Cultured; Coculture Techniques; Compressive Strength; Dental Stress Analysis; Female; Glycoproteins; Humans; Male; Membrane Glycoproteins; Osteoclasts; Osteoprotegerin; Periodontal Ligament; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; Root Resorption; Tooth Movement Techniques

Receptor activator of nuclear factor kappa beta ligand (RANKL) activates osteoclast differentiation, whereas this activity is blocked by osteoprotegrin (OPG), so that the relative expression of these 2 proteins might contribute to bone and root resorption during orthodontic tooth movement. We describe experiments with RANKL and OPG mRNA expression in rats subjected to orthodontic forces. It was hypothesized that the ratios of RANKL to OPG expression would increase during root resorption processes.. Fixed Sentalloy (GAC, Bohemia, NY) closed-coil springs capable of delivering approximately 100 g of force were applied for mesial movement of the mandibular left first molar in 9 male, 7-week-old Wistar rats; the right mandibular molar was used as an internal control for each animal. After 14 days, the rats were killed; tissues from 2 rats were examined by paraffin histology, and high-quality messenger ribonucleic acid (mRNA) was extracted from 4-mm widths of the mesial bony tissues in the remaining animals.. Paraffin sections showed osteoclastic resorption of roots on the mesial surfaces of teeth subjected to orthodontic forces. The integrity of mRNA was confirmed by reverse transcriptase polymerase chain reaction (RT-PCR) for the housekeeping gene GAPDH, and that of primers specific for OPG and RANKL was determined by RT-PCR for these genes in material isolated from the UM106 rat cell line known to express both proteins. Densitometric analysis of the RT-PCR OPG product showed an increase in background levels of OPG mRNA in bony tissues subjected to orthodontic forces in all animals studied (P < .05). In contrast, low levels of mRNA for RANKL were detected in only 5 animals and only in association with orthodontic forces.. Data are consistent with changes in levels of OPG and RANKL in tissues subjected to orthodontic forces and experiencing root resorption.

Topics: Animals; Carrier Proteins; Glycoproteins; Male; Mandible; Membrane Glycoproteins; Molar; Osteoclasts; Osteoprotegerin; RANK Ligand; Rats; Rats, Wistar; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Root Resorption; Tooth Movement Techniques

External apical root resorption (EARR) is a common orthodontic treatment sequela. Previous studies implicate a substantial genetic component for EARR. Using a candidate gene approach, we investigated possible linkage of EARR associated with orthodontic treatment with the TNSALP, TNFalpha, and TNFRSF11A gene loci. The sample was comprised of 38 American Caucasian families with a total of 79 siblings who completed comprehensive orthodontic treatment. EARR was assessed by means of pre- and post-treatment radiographs. Buccal swab cells were collected for extraction and analysis of DNA. No evidence of linkage was found with EARR and the TNFalpha and TNSALP genes. Non-parametric sibling pair linkage analysis identified evidence of linkage (LOD = 2.5; p = 0.02) of EARR affecting the maxillary central incisor with the microsatellite marker D18S64 (tightly linked to TNFRSF11A). This indicates that the TNFRSF11A locus, or another tightly linked gene, is associated with EARR.

Topics: Child; Chromosomes, Human, Pair 18; Female; Genetic Linkage; Genetic Markers; Genetic Predisposition to Disease; Glycoproteins; Humans; Male; Malocclusion; Microsatellite Repeats; Orthodontics, Corrective; Osteoprotegerin; Pedigree; Polymorphism, Genetic; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; Root Resorption; Siblings; Statistics, Nonparametric

Although important roles of receptor activator of NF-kappaB ligand (RANKL) and its receptor (RANK) have been established for osteoclastogenesis and bone resorption, their expression and roles during physiological root resorption remain uncertain. Physiological root resorption for shedding of human deciduous teeth is mediated by osteoclast-like cells (odontoclasts). In this study, we examined the expression of RANKL and osteoprotegerin (OPG), a decoy receptor that prevents RANKL from binding to RANK in human periodontal ligament (PDL) cells during physiological root resorption using immunocytochemistry and reverse transcriptase polymerase chain reaction. The effect of RANKL on root resorbing activity of odontoclasts was evaluated by measuring the size of dissolved area on calcium phosphate-coated coverslips. The PDL cells isolated from either non-resorbing deciduous teeth or permanent teeth abundantly expressed OPG, but not RANKL. In contrast, PDL cells derived from resorbing deciduous teeth dominantly expressed RANKL. Human odontoclasts derived from resorbing deciduous teeth expressed both RANKL and RANK. It was observed that RANKL increased odontoclast actin ring formation and resorbing activity in a dose-dependent manner. These results indicate that PDL cells during the root-resorbing state express RANKL but decrease OPG expression. Expression of RANKL likely participates in odontoclastogenesis and activates physiological root resorption.

Topics: Actins; Analysis of Variance; Calcium Phosphates; Carrier Proteins; Cell Culture Techniques; Dose-Response Relationship, Drug; Gene Expression Regulation; Glycoproteins; Humans; Ligands; Membrane Glycoproteins; Microfilament Proteins; NF-kappa B; Osteoclasts; Osteoprotegerin; Periodontal Ligament; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; Root Resorption; Tooth, Deciduous

Periodontal ligament (PDL) cells play an important role in maintaining the homeostasis of periodontal tissues. However, it is not known how PDL cells contribute to osteoclastogenesis. In this study, we examined the consequences of cell-to-cell interactions between peripheral blood mononuclear cells (PBMCs) and PDL cells during osteoclastogenesis. PBMCs were co-cultured directly or indirectly with PDL cells for two to four weeks. PBMCs that were directly co-cultured with PDL cells formed significantly more resorption pits on dentin slices than did PBMCs that were cultured alone. However, soluble factor(s) produced from PDL cells inhibited the formation of tartrate-resistant acid phosphatase (TRAP)-positive multinucleated cells. Furthermore, PDL cells expressed both receptor activator nuclear factor kappa B ligand (RANKL) and osteoprotegerin (OPG) mRNA. In conclusion, PDL cells support osteoclastogenesis through cell-to-cell contact. PDL cells might regulate osteoclastogenesis by opposing mechanisms--stimulation of resorptive activity by RANKL and inhibition by OPG--thus affecting processes such as periodontitis and orthodontic tooth movement.

Topics: Acid Phosphatase; Adult; Animals; Carrier Proteins; Cattle; Cell Communication; Cell Differentiation; Cells, Cultured; Coculture Techniques; Dentin; Enzyme Inhibitors; Glycoproteins; Humans; Isoenzymes; Leukocytes, Mononuclear; Ligands; Male; Membrane Glycoproteins; NF-kappa B; Osteoclasts; Osteoprotegerin; Periodontal Ligament; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; RNA, Messenger; Root Resorption; Tartrate-Resistant Acid Phosphatase; Tumor Necrosis Factor-alpha