RESUMEN
This study aimed to evaluate the effects of the estrogen depression during orthodontic tooth movement on alveolar bone microarchitecture and periodontal ligament. Female Wistar rats were divided into two groups, one consisting of non-ovariectomized animals subjected to orthodontic tooth movement, and one comprising ovariectomized animals subjected to orthodontic tooth movement. Micro-CT assessment of bone volume to total volume (BV/TV), total porosity, trabecular thickness (Tb.Th), trabecular number (Tb.N), and trabecular separation (Tb.Sp) in the alveolar bone of the orthodontically moved tooth was performed. Histomorphometric analyses were made in the periodontal ligament, and immunoexpression of RANK, RANKL, OPG, and TUNEL were quantified. Orthodontic tooth movement in the group of ovariectomized rats was faster than in non-ovariectomized animals. The alveolar bone area showed lower values of BV/TV and trabecular thickness, and higher bone porosity and trabeculae numbers in the ovariectomized rats. Histological analyses in the ovariectomized group revealed an increase in collagen fibers in the periodontal ligament. The apoptotic cell counts in the periodontal ligament were higher in the group of ovariectomized rats than in the sham-operated rats. Ovariectomy resulted in an increase in tooth movement and alteration of the alveolar bone microstructure in the first 7 day of orthodontic tooth movement, and in the presence of apoptotic cells in the periodontal ligament.
Asunto(s)
Proceso Alveolar , Estrógenos , Ovariectomía , Ligamento Periodontal , Ratas Wistar , Técnicas de Movimiento Dental , Microtomografía por Rayos X , Animales , Ligamento Periodontal/patología , Técnicas de Movimiento Dental/efectos adversos , Femenino , Proceso Alveolar/patología , Proceso Alveolar/diagnóstico por imagen , Ratas , Apoptosis , Ligando RANK/metabolismo , Osteoprotegerina/metabolismo , Receptor Activador del Factor Nuclear kappa-B/metabolismo , Densidad Ósea , Etiquetado Corte-Fin in SituRESUMEN
Periapical lesions are common pathologies affecting the alveolar bone, often initiated by intraradicular lesions resulting from microbial exposure to dental pulp. These microorganisms trigger inflammatory and immune responses. When endodontic treatment fails to eliminate the infection, periapical lesions persist, leading to bone loss. The RANK/RANKL/OPG pathway plays a crucial role in both the formation and the destruction of the bone. In this study, the objective was to inhibit the RANK/RANKL pathway in vitro within exposed Thp-1 macrophages to endodontic microorganisms, specifically Enterococcus faecalis, which was isolated from root canals of 20 patients with endodontic secondary/persistent infection, symptomatic and asymptomatic, and utilizing an α-IRAK-4 inhibitor, we introduced endodontic microorganisms and/or lipoteichoic acid from Streptococcus spp. to cellular cultures in a culture plate, containing thp-1 cells and/or PBMC from patients with apical periodontitis. Subsequently, we assessed the percentages of RANK+, RANKL+, and OPG+ cells through flow cytometry and measured the levels of several inflammatory cytokines (IL-1ß, TNF-α, IL-6, IL-8, IL-10, and IL-12p70) in the cellular culture supernatant through a CBA kit and performed analysis by flow cytometry. A significant difference was observed in the percentages of RANK+RANKL+, OPG+ RANKL+ cells in thp-1 cells and PBMCs from patients with apical periodontitis. The findings revealed significant differences in the percentages of the evaluated cells, highlighting the novel role of the IRAK-4 inhibitor in addressing this oral pathology, apical periodontitis, where bone destruction is observed.
Asunto(s)
Macrófagos , Periodontitis Periapical , Ligando RANK , Receptor Activador del Factor Nuclear kappa-B , Transducción de Señal , Humanos , Ligando RANK/metabolismo , Macrófagos/metabolismo , Macrófagos/efectos de los fármacos , Macrófagos/inmunología , Células THP-1 , Receptor Activador del Factor Nuclear kappa-B/metabolismo , Periodontitis Periapical/metabolismo , Periodontitis Periapical/microbiología , Periodontitis Periapical/patología , Citocinas/metabolismo , Enterococcus faecalis , Lipopolisacáridos , Cavidad Pulpar/microbiología , Cavidad Pulpar/metabolismo , Masculino , Osteoprotegerina/metabolismo , Adulto , Ácidos Teicoicos/farmacologíaRESUMEN
INTRODUCTION: Caffeine is a widely consumed substance with several effects on bone metabolism. This study aimed to investigate the effect of caffeine on the bone tissue of rats submitted to orthodontic movement. METHODS: Twenty-five male Wistar rats underwent orthodontic movement (21 days) of the first permanent maxillary molars on the left side. The experimental group (caffeine; n = 13) and control group (n = 12) received caffeine and water, respectively, by gavage. Microcomputed tomography was performed to analyze orthodontic movement. Histologic analysis of the inflammatory infiltrate and osteoclast count by tartrate-resistant acid phosphatase were conducted. Maxilla tissue was evaluated for receptor activator of nuclear factor Ò¡B (RANK), RANK ligand (RANKL), and osteoprotegerin by immunohistochemistry. RESULTS: Caffeine exhibited a lower bone volume/tissue volume ratio (78.09% ± 5.83%) than the control (86.84% ± 4.89%; P <0.05). Inflammatory infiltrate was increased in the caffeine group compared with the control group (P <0.05). A higher number of tartrate-resistant acid phosphatase-positive cells was observed in the caffeine (9.67 ± 1.73) than in the control group (2.66 ± 0.76; P <0.01). Immunoexpression of RANK and RANKL in the caffeine group was greater than the control (P <0.05). CONCLUSIONS: The use of caffeine thermogenic induces alveolar bone loss in rats submitted to orthodontic movement via activation of RANK, RANKL, and osteoprotegerin signaling pathways.
Asunto(s)
Pérdida de Hueso Alveolar , Cafeína , Osteoprotegerina , Ligando RANK , Receptor Activador del Factor Nuclear kappa-B , Técnicas de Movimiento Dental , Animales , Masculino , Ratas , Pérdida de Hueso Alveolar/metabolismo , Pérdida de Hueso Alveolar/patología , Cafeína/farmacología , Maxilar/efectos de los fármacos , Osteoclastos/efectos de los fármacos , Osteoprotegerina/metabolismo , Ligando RANK/metabolismo , Ratas Wistar , Receptor Activador del Factor Nuclear kappa-B/metabolismo , Transducción de Señal/efectos de los fármacos , Técnicas de Movimiento Dental/efectos adversos , Microtomografía por Rayos XRESUMEN
The bone-muscle unit refers to the reciprocal regulation between bone and muscle by mechanical interaction and tissue communication via soluble factors. The RANKL stimulation induces mitochondrial biogenesis and increases the oxidative capacity in osteoclasts and adipocytes. RANKL may bind to the membrane bound RANK or to osteoprotegerin (OPG), a decoy receptor that inhibits RANK-RANKL activation. RANK is highly expressed in skeletal muscle, but the contribution of RANKL to healthy skeletal muscle fiber remains elusive. Here we show that RANKL stimulation in C2C12-derived myotubes induced activation of mitochondrial biogenesis pathways as detected by RNA-seq and western blot. RANKL expanded the mitochondrial reticulum, as shown by mitochondrial DNA quantification and MitoTracker staining, and boosted the spare respiratory capacity. Using MEK and MAPK inhibitors, we found that RANKL signals via ERK and p38 to induce mitochondrial biogenesis. The soleus from OPG-/- and OPG+/- mice showed higher respiratory rates compared to C57BL6/J WT mice, which correlates with high serum RANKL levels. RANKL infusion using a mini-osmotic pump in WT mice increased the number of mitochondria, boosted the respiratory rate, increased succinate dehydrogenase activity in skeletal muscle, and improved the fatigue resistance of gastrocnemius. Therefore, our findings reveal a new role of RANKL as an osteokine-like protein that impacts muscle fiber metabolism.
Bone modeling and remodeling are processes intricately related to bone health regulated by the RANKL system. The RANKL is a protein essential for bone resorption. RANKL activates RANK in the cell membrane of osteoclasts and can also bind to osteoprotegerin (OPG), which acts as a soluble decoy receptor. Therefore, the levels of RANKL and OPG determine the degree of osteoclast activation and bone resorption. Bone and muscle mechanically interact for movement as bone is a lever for skeletal muscle to exert force. They also communicate via soluble factors that reciprocally regulate their function. Skeletal muscle fibers express RANK, but the role of RANKL signaling in healthy myotubes was still unknown. Here, we propose that RANKL regulates muscle metabolism by inducing mitochondrial biogenesis. We show that RANKL increases mitochondrial area in myotubes and the expression of mitochondrial markers, boosting the spare respiratory capacity. In mice knockout for OPG, which shows high levels of RANKL and unopposed RANKRANKL stimulation, we found higher respiratory rates than in the wild-type mice. We also infused a low dose of RANKL in wild-type mice, which is around 10 times lower than the dose to induce osteoporosis, and found increased mitochondrial number and higher respiratory rates in soleus. In the gastrocnemius, we also observed increased phosphorylative respiration and improved resistance to fatigue compared to mice treated with the vehicle solution. Our findings indicate that RANKL regulates both bone and muscle under physiological conditions by inducing mitochondrial biogenesis and oxidative metabolism in skeletal muscle fibers.
Asunto(s)
Músculo Esquelético , Ligando RANK , Transducción de Señal , Animales , Ligando RANK/metabolismo , Ratones , Músculo Esquelético/metabolismo , Transducción de Señal/efectos de los fármacos , Ratones Endogámicos C57BL , Osteoprotegerina/metabolismo , Oxidación-Reducción , Fibras Musculares Esqueléticas/metabolismo , Fibras Musculares Esqueléticas/efectos de los fármacos , Ratones Noqueados , Línea Celular , Biogénesis de Organelos , Respiración de la Célula/efectos de los fármacos , Masculino , Mitocondrias/metabolismoRESUMEN
BACKGROUND AND PURPOSE: Rheumatoid arthritis (RA) is a chronic autoimmune disease that can cause bone erosion due to increased osteoclastogenesis. Neutrophils involvement in osteoclastogenesis remains uncertain. Given that neutrophil extracellular traps (NETs) can act as inflammatory mediators in rheumatoid arthritis, we investigated the role of NETs in stimulating bone loss by potentiating osteoclastogenesis during arthritis. EXPERIMENTAL APPROACH: The level of NETs in synovial fluid from arthritis patients was assessed. Bone loss was evaluated by histology and micro-CT in antigen-induced arthritis (AIA)-induced WT mice treated with DNase or in Padi4-deficient mice (Padi4flox/flox LysMCRE ). The size and function of osteoclasts and the levels of RANKL and osteoprotegerin (OPG) released by osteoblasts that were incubated with NETs were measured. The expression of osteoclastogenic marker genes and protein levels were evaluated by qPCR and western blotting. To assess the participation of TLR4 and TLR9 in osteoclastogenesis, cells from Tlr4-/- and Tlr9-/- mice were cultured with NETs. KEY RESULTS: Rheumatoid arthritis patients had higher levels of NETs in synovial fluid than osteoarthritis patients, which correlated with increased levels of RANKL/OPG. Moreover, patients with bone erosion had higher levels of NETs. Inhibiting NETs with DNase or Padi4 deletion alleviated bone loss in arthritic mice. Consistently, NETs enhanced RANKL-induced osteoclastogenesis that was dependent on TLR4 and TLR9 and increased osteoclast resorptive functions in vitro. In addition, NETs stimulated the release of RANKL and inhibited osteoprotegerin in osteoblasts, favouring osteoclastogenesis. CONCLUSIONS AND IMPLICATIONS: Inhibiting NETs could be an alternative strategy to reduce bone erosion in arthritis patients.
Asunto(s)
Artritis Reumatoide , Trampas Extracelulares , Humanos , Animales , Ratones , Osteoprotegerina/metabolismo , Osteoprotegerina/farmacología , Osteogénesis , Trampas Extracelulares/metabolismo , Receptor Toll-Like 4/metabolismo , Receptor Toll-Like 9/metabolismo , Artritis Reumatoide/metabolismo , Osteoclastos/metabolismo , Desoxirribonucleasas/metabolismo , Ligando RANK/metabolismoRESUMEN
INTRODUCTION: In chronic arthropathies, there are several mechanisms of joint destruction. In recent years, studies have reported the implication of receptor activator of nuclear factor kappa-B ligand (RANKL) and osteoprotegerin (OPG) in the process of activation and differentiation of osteoclasts, a key cell in the development of bone erosion. The RANKL/OPG ratio is increased in the serum of patients with malignant diseases and lytic bone disease, as well as rheumatoid arthritis (RA). The objective of this study was to measure and compare the concentrations of OPG and RANKL in the synovial fluid (SF) of patients with rheumatoid arthritis, spondyloarthritis (SpA) and osteoarthritis (OA). METHODS: This was an observational and cross-sectional study with 83 patients, 33 with RA, 32 with SpA and 18 with OA, followed up regularly in the outpatient clinics of the Rheumatology Department of the Clinics Hospital of the Ribeirão Preto Medical School-USP. All patients were assessed for indications for arthrocentesis by the attending physicians at the time of SF collection and were evaluated for demographic variables and medication use. Disease activity was assessed in individuals with RA and SpA. The quantification of SF OPG and RANKL levels was performed by ELISA, and the correlations of the results with clinical, laboratory and radiological parameters were assessed. RESULTS: We found no statistically significant difference in the RANKL and OPG levels among the groups. Patients with RA showed a positive correlation between the SF cell count and RANKL level (r = 0.59; p < 0.05) and the RANKL/OPG ratio (r = 0.55; p < 0.05). Patients with OA showed a strong correlation between C-reactive protein (CRP) and the RANKL/OPG ratio (r = 0.82; p < 0.05). There was no correlation between the OPG and RANKL levels and markers of inflammatory activity or the disease activity index in patients with RA or SpA. CONCLUSION: Within this patient cohort, the RANKL/OPG ratio was correlated with the SF cell count in patients with RA and with serum CRP in patients with OA, which may suggest a relationship with active inflammation and more destructive joint disease.
Asunto(s)
Artritis Reumatoide , Osteoartritis , Espondiloartritis , Humanos , Osteoprotegerina/metabolismo , FN-kappa B , Estudios Transversales , LigandosRESUMEN
INTRODUCTION: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: These findings suggest that smoking is capable of altering the inflammatory response, influencing the evolution of CAP.
Asunto(s)
Periodontitis Periapical , Periodontitis , Humanos , Adolescente , Lactante , Osteoprotegerina/metabolismo , Factor de Necrosis Tumoral alfa , Fumadores , Ligando RANK/metabolismo , FN-kappa B , Osteopontina , Periodontitis Periapical/metabolismoRESUMEN
Duchenne muscular dystrophy (DMD) is an X-linked inherited disorder. Patients present with decreased bone mineral density (BMD) due to glucocorticoid therapy and progressive muscle weakness. Bone remodeling allows bone volume and structure to be maintained and controlled by local and systemic factors. These include the receptor activator of the nuclear factor-kB (RANK)/RANK ligand (RANKL)/osteoprotegerin (OPG) system, a determining pathway in the balance between bone formation and resorption. Disruptions in this complex, caused by factors such as glucocorticoids, can affect bone metabolism. The extensive action of the RANK/RANKL/OPG pathway suggests an influence on dystrophic muscle pathophysiology. This review aimed to highlight some aspects of the RANK/RANKL/OPG system, the effect of glucocorticoids on this pathway, and the pathophysiology of the patient with DMD.
La distrofia muscular de Duchenne (DMD) es un trastorno hereditario ligado al cromosoma X. Los pacientes presentan una disminución de la densidad mineral ósea (DMO) debido a los efectos adversos del tratamiento con glucocorticoides y a la debilidad muscular progresiva. El remodelado óseo permite mantener el volumen y la estructura ósea, proceso controlado por factores locales y sistémicos. Entre ellos destaca el sistema del receptor activador del factor nuclear-kB (RANK), su ligando natural RANKL (RANKL) y la osteoprotegerina (OPG), una vía determinante en el equilibrio entre la resorción y formación ósea. Las alteraciones en este complejo, originadas por factores como los glucocorticoides, pueden afectar el metabolismo óseo. La amplia acción de RANKL y OPG ha sugerido una influencia en la fisiopatología de la DMD. El objetivo de esta revisión fue destacar algunos aspectos del sistema RANK/RANKL/OPG, el efecto de los glucocorticoides en esta vía y la fisiopatología del paciente con DMD.
Asunto(s)
Distrofia Muscular de Duchenne , Osteoprotegerina , Humanos , Glucocorticoides/farmacología , Distrofia Muscular de Duchenne/tratamiento farmacológico , Osteoprotegerina/genética , Osteoprotegerina/metabolismo , Ligando RANK/metabolismo , Receptor Activador del Factor Nuclear kappa-B/metabolismoRESUMEN
OBJECTIVE: To investigate the effect of voluntary physical activity (VPA) on inflammatory profile and the progression of experimental periodontal disease (PD) in mice. METHODS: Male C57BL/6 mice were randomly distributed into Control; VPA; PD and PD/VPA groups. We registered VPA (total volume of revolutions) and average speed (revolutions/minute) in a free running wheel for 30 days. On the 15th day, animals from the PD and PD/VPA groups received ligatures on the upper second molars bilaterally. On the 30th day animals were euthanized, and PD progression was assessed by measuring alveolar bone loss (ABL - the linear distance between the cemento-enamel junction and the alveolar bone crest on the teeth buccal surface). Gene expression of RANKL (kappa nuclear factor B receptor) OPG (osteoprotegerin), IL-1ß (interleukin 1 beta), IL-6 (interleukin 6) and TNF-α (tumor necrosis factor alpha) were evaluated by real-time PCR (quantitative Polymerase Chain Reaction - relative gene expression). RESULTS: The total volume of physical activity and the activity speed decreased along the seven days after ligature-placement (p < 0.05), returning to a similar pattern in relation to VPA group. Ligature placement produced significant bone resorption, and increased RANKL, IL-1ß, IL-6 and TNF-α expression. VPA reduced ABL (p < 0,05) and the expression of TNF-α and IL-1ß, whereas increased OPG expression. CONCLUSION: Animals induced to PD with access to the VPA wheel presented both lower gingival inflammation and less alveolar bone resorption in comparison to animals without access to the wheel.
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Pérdida de Hueso Alveolar , Periodontitis , Pérdida de Hueso Alveolar/patología , Animales , Interleucina-6 , Masculino , Ratones , Ratones Endogámicos C57BL , Osteoprotegerina/metabolismo , Periodontitis/metabolismo , Ligando RANK/metabolismo , Factor de Necrosis Tumoral alfa/metabolismoRESUMEN
High serum levels of osteoprotegerin (OPG) are found in patients with obesity, type 2 diabetes, sepsis, or septic shock and are associated with a high mortality rate in stroke. The primary known function of OPG is to bind to the receptor activator of NF-κB ligand (RANKL), and by doing so, it inhibits the binding between RANKL and its receptor (RANK). TLR4 signaling in macrophages involves TRAF6 recruitment and contributes to low-grade chronic inflammation in adipose tissue. LPS is a classical activator of the TLR4 pathway and induces the expression of inflammatory cytokines in macrophages. We have previously observed that in the presence of RANKL, there is no LPS-induced activation of TLR4 in macrophages. In this study, we investigated the crosstalk between RANK and TLR4 pathways in macrophages stimulated with both RANKL and LPS to unveil the role of OPG in inflammatory processes. We found that RANKL inhibits TLR4 activation by binding to RANK, promoting the binding between TRAF6 and RANK, lowering TLR4 activation and the expression of proinflammatory mediators. Furthermore, high OPG levels aggravate inflammation by inhibiting RANKL. Our findings elect RANKL as a candidate for drug development as a way to mitigate the impact of obesity-induced inflammation in patients.
Asunto(s)
Macrófagos , Osteoprotegerina , Ligando RANK , Receptor Activador del Factor Nuclear kappa-B , Factor 6 Asociado a Receptor de TNF , Receptor Toll-Like 4 , Diabetes Mellitus Tipo 2/genética , Diabetes Mellitus Tipo 2/metabolismo , Humanos , Inflamación/genética , Inflamación/metabolismo , Lipopolisacáridos/metabolismo , Macrófagos/metabolismo , Obesidad/genética , Obesidad/metabolismo , Osteoprotegerina/sangre , Osteoprotegerina/genética , Osteoprotegerina/metabolismo , Ligando RANK/metabolismo , Receptor Activador del Factor Nuclear kappa-B/genética , Receptor Activador del Factor Nuclear kappa-B/metabolismo , Factor 6 Asociado a Receptor de TNF/genética , Factor 6 Asociado a Receptor de TNF/metabolismo , Receptor Toll-Like 4/genética , Receptor Toll-Like 4/metabolismoRESUMEN
OBJECTIVE: Periodontitis (POD) is an infectious process directed at the structures supporting the teeth. Destruction of alveolar bone is considered one of the main causes of tooth loss in humans and is mediated by the host immune response. Osteoprotegerin (OPG), a protein that inhibits bone resorption by binding to the RANK ligand (RANKL), prevents osteoclastic differentiation. The aim of the study was to determine the plasma levels of OPG in patients with POD. METHODS: a case-control study with forty-nine patients with POD and 49 healthy controls were included in the study. OPG levels were determined by an ELISA test in plasma samples. RESULTS: OPG values (1.6203 ng/mL) were higher in the POD group compared with control group (1.2824 ng/mL). Among the studied groups, we detected significant differences in age, glycosylated haemoglobin (HbA1C), and plasma concentration of OPG (p < 0.05). CONCLUSION: plasma OPG levels are associated with bone formation and destruction processes, suggesting that OPG acts in a protective manner.
Asunto(s)
Pérdida de Hueso Alveolar , Periodontitis , Pérdida de Hueso Alveolar/complicaciones , Pérdida de Hueso Alveolar/metabolismo , Pérdida de Hueso Alveolar/prevención & control , Estudios de Casos y Controles , Humanos , Osteoprotegerina/metabolismo , Periodontitis/complicaciones , Periodontitis/metabolismo , Ligando RANK/metabolismoRESUMEN
OBJECTIVES: Many species of theBauhinia genus have been widely used in folk medicine as analgesic, anti-inflammatory and antioxidant agents. (-)-Fisetinidol palmitate is a semi-syntetic flavonoid obtained from the ethanolic extract of the stem of Bauhinia pulchella. This study aimed to evaluate the antiresorptive effect of the semi-syntetic (-)-fisetinidol palmitate in ligature-induced periodontitis in rats. Also, it evaluated the mechanism of action of (-)-fisetinidol palmitate and its toxicity. DESIGN: Periodontitis was inducedvia a nylon thread ligature (3.0) around the second upper left molars. Rats were treated (oral gavage) once a day for 11 days with (-)-fisetinidol palmitate (0.01 or 0.1â¯mg/kg) or saline vehicle. RESULTS: (-)-Fisetinidol palmitate (0.1â¯mg/kg) reduced alveolar bone loss, increased bone alkaline phosphatase (BALP), superoxide dismutase (SOD), and catalase (CAT) activity; also, it decreased IL1-ß, IL-8/CINC-1, nitrite/nitrate levels and myeloperoxidase activity. (-)-Fisetinidol palmitate reduced the mRNA levels of IL1-ß, IL-6, RANK, and RANK-L, while it increased the OPG ones. No statistical differences (Pâ¯>â¯0.05) were observed in the transaminases (ALT, AST) and Total Alkaline Phosphatase (TALP) levels among groups. (-)- CONCLUSIONS: Fisetinidol palmitate did not result in any signs of toxicity and had anti-resorptive effects in a pre-clinical trial of periodontitis, showing antioxidant activity with the involvement of the RANK/RANKL/OPG pathway.
Asunto(s)
Bauhinia/química , Flavonoides/farmacología , Osteólisis , Estrés Oxidativo , Periodontitis , Pérdida de Hueso Alveolar/prevención & control , Animales , Antioxidantes/farmacología , Citocinas/metabolismo , Osteoprotegerina/metabolismo , Periodontitis/tratamiento farmacológico , Periodontitis/prevención & control , Fitoquímicos/farmacología , Tallos de la Planta/química , Ligando RANK/metabolismo , Ratas , Ratas WistarRESUMEN
The receptor activator of nuclear factor-κB (NF-κB) (RANK), its ligand (RANKL), and the decoy receptor osteoprotegerin (OPG) are a triad of proteins that regulate bone metabolism, and serum OPG is considered a biomarker for cardiovascular diseases and Type 2 diabetes; however, the implications of OPG in adipose tissue metabolism remains elusive. In this study, we investigate RANK-RANKL-OPG signaling in white adipose tissue browning. Histological analysis of osteoprotegerin knockout (OPG-/-) mice showed subcutaneous white adipose tissue (sWAT) browning, resistance for high-fat diet-induced weight gain, and preserved glucose metabolism compared with wild-type (WT) mice. Stromal vascular fraction (SVF) cells from sWAT of OPG-/- mice showed multilocular morphology and higher expression of brown adipocyte marker genes compared with those from the WT group. Infusion of RANKL induced browning and elevated respiratory rates in sWAT, along with increased whole body oxygen consumption in mice measured by indirect calorimetry. Subcutaneous WAT-derived SVF and 3T3-L1 cells, but not mature white adipocytes, differentiated into beige adipose tissue in the presence of RANKL. Moreover, SVF cells, even under white adipocyte differentiation, showed multilocular lipid droplet, lower lipid content, and increased expression of beige adipocyte markers with RANKL stimulation. In this study, we show for the first time the contribution of RANKL to increase energy expenditure by inducing beige adipocyte differentiation in preadipocytes.
Asunto(s)
Adipocitos Beige/metabolismo , Adipogénesis/genética , Tejido Adiposo Blanco/metabolismo , Obesidad/metabolismo , Osteoprotegerina/genética , Ligando RANK/metabolismo , Receptor Activador del Factor Nuclear kappa-B/metabolismo , Células 3T3-L1 , Adipocitos Beige/citología , Adipocitos Beige/ultraestructura , Adipocitos Blancos/citología , Adipocitos Blancos/metabolismo , Adipocitos Blancos/ultraestructura , Tejido Adiposo Beige/citología , Tejido Adiposo Beige/metabolismo , Tejido Adiposo Blanco/citología , Animales , Calorimetría Indirecta , Dieta Alta en Grasa , Metabolismo Energético/efectos de los fármacos , Metabolismo Energético/genética , Gotas Lipídicas/ultraestructura , Ratones , Ratones Noqueados , Osteoprotegerina/metabolismo , Consumo de Oxígeno/efectos de los fármacos , Consumo de Oxígeno/genética , Ligando RANK/farmacología , Transducción de Señal , Grasa Subcutánea/efectos de los fármacos , Grasa Subcutánea/metabolismo , Aumento de Peso/efectos de los fármacos , Aumento de Peso/genéticaRESUMEN
PURPOSE OF REVIEW: The aim of this review is to gain a better understanding of osteoporotic fractures and the different mechanisms that are driven in the scenarios of bone disuse due to spinal cord injury and osteometabolic disorders due to diabetes. RECENT FINDINGS: Despite major advances in understanding the pathogenesis, prevention, and treatment of osteoporosis, the high incidence of impaired fracture healing remains an important complication of bone loss, leading to marked impairment of the health of an individual and economic burden to the medical system. This review underlines several pathways leading to bone loss and increased risk for fractures. Specifically, we addressed the different mechanisms leading to bone loss after a spinal cord injury and diabetes. Finally, it also encompasses the changes responsible for impaired bone repair in these scenarios, which may be of great interest for future studies on therapeutic approaches to treat osteoporosis and osteoporotic fractures.
Asunto(s)
Resorción Ósea/metabolismo , Diabetes Mellitus/metabolismo , Osteoporosis/metabolismo , Fracturas Osteoporóticas/epidemiología , Traumatismos de la Médula Espinal/metabolismo , Remodelación Ósea , Resorción Ósea/complicaciones , Resorción Ósea/fisiopatología , Callo Óseo , Complicaciones de la Diabetes/metabolismo , Complicaciones de la Diabetes/fisiopatología , Diabetes Mellitus/fisiopatología , Curación de Fractura , Humanos , Osteoporosis/etiología , Osteoporosis/fisiopatología , Fracturas Osteoporóticas/etiología , Osteoprotegerina/metabolismo , Ligando RANK/metabolismo , Traumatismos de la Médula Espinal/complicaciones , Vía de Señalización WntRESUMEN
OBJECTIVE: TNF-α, which acts directly on osteoclastogenesis, may modify bone turnover. Thus, the objective of this study was to evaluate the influence of infliximab on extraction socket healing. MATERIAL AND METHODS: Eighty-four Wistar rats were randomized into two groups (infliximab EV 5 mg / kg or saline EV 1 ml / kg) and submitted to lower first molar extraction protocol. The animals were sacrificed 1, 3, 7, 14, 21 and 28 days after surgery. The jaws were subjected to radiographic, histomorphometric, histochemical (picrosirius red) and immunohistochemical (TNF-α, RANKL and OPG) analysis. RESULTS: No differences were observed between the groups in surgical difficulty parameters: mass of teeth, number of root fractures and surgical time. Lower area filling with bone as well as increased amounts of remaining cicatricial tissue were observed in the infliximab group at 14 days (p < 0.001). Lower scores for polymorphonuclear neutrophils were seen at 3 (p < 0.01) and 7 days (p < 0.001), lower mononuclear counts at 7 days (p < 0.01) and lower osteoclast counts at 7 and 14 days (p < 0.01 and p < 0.001, respectively). Additionally, reduced TNF-α, RANKL and OPG immunoreactivity were observed, especially at 7 days (p < 0.05). CONCLUSION: TNF-α inhibitor may alter the bone repair capacity after tooth extraction, especially in the initial repair periods, by lower expression of TNF α, RANKL and OPG. Thus, additional caution may be needed in patients who use this class of medication after dental extraction.
Asunto(s)
Remodelación Ósea , Infliximab/uso terapéutico , Extracción Dental , Cicatrización de Heridas , Animales , Osteoprotegerina/metabolismo , Ligando RANK/metabolismo , Distribución Aleatoria , Ratas , Ratas Wistar , Inhibidores del Factor de Necrosis Tumoral/uso terapéutico , Factor de Necrosis Tumoral alfa/antagonistas & inhibidores , Factor de Necrosis Tumoral alfa/metabolismoRESUMEN
BACKGROUND AND OBJECTIVES: Strontium ranelate is a medication indicated for the treatment of osteoporosis that presents concomitant anti-resorptive and osteoanabolic dual biological activity. However, the effects of strontium ranelate on alveolar bone have been poorly explored. Furthermore, to date, there are no data on the effects of this medication on alveolar bone loss (BL) during conditions of estrogen deficiency. Therefore, the aim of this study was to evaluate the effects of strontium ranelate on ligature-induced periodontitis in estrogen-deficient and estrogen-sufficient rats. METHODS: Ninety-six rats were assigned to one of the following groups: sham-surgery + water (estrogen-sufficient; n = 24); ovariectomy + water (estrogen-deficient; n = 24), sham-surgery + strontium ranelate (ranelate/estrogen-sufficient; n = 24) and; ovariectomy + strontium ranelate (ranelate/estrogen-deficient; n = 24). The rats received strontium ranelate or water from the 14th day after ovariectomy until the end of the experiment. On the 21st day after ovariectomy, one first mandibular molar received a ligature, while the contralateral tooth was left unligated. Eight rats per group were killed at 10, 20, and 30 days after ligature placement. Bone loss (BL) and trabecular bone area (TBA) were analyzed in the furcation area of ligated and unligated teeth at all experimental times by histometry. Tartrate-resistant acid phosphatase (TRAP) positive cells and immunohistochemical staining for osteocalcin (OCN), osteopontin (OPN), osteoprotegerin (OPG), and receptor activator of NF-ÐB ligand (RANKL) were assessed in the ligated teeth at 30 days after ligature placement. RESULTS: At 10 and 30 days, ligated teeth of the estrogen-deficient group exhibited higher BL, when compared to all other groups (P < .05). At 10 days, TBAs were higher in the unligated teeth of strontium ranelate-treated groups, when compared to those of untreated groups (P < .05). At 30 days, the ligated teeth of the estrogen-deficient group exhibited lower TBA than the other groups (P < .05). There were no differences among groups regarding the number of TRAP-stained cells (P < .05). The strontium ranelate-treated groups exhibited lower expressions of OCN and RANKL than the untreated groups (P < .05). The estrogen-sufficient group presented higher staining for OPG than both treated and untreated estrogen-deficient groups (P < .05). CONCLUSIONS: Strontium ranelate prevented ligature-induced BL in an estrogen-deficiency condition and, to a certain extent, increased TBA in the presence and absence of periodontal collapse in states of estrogen deficiency and estrogen sufficiency. Furthermore, strontium ranelate also affected the expression of bone markers, appearing to have acted predominantly as an anti-resorptive agent.
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Pérdida de Hueso Alveolar/tratamiento farmacológico , Estrógenos/deficiencia , Periodontitis/tratamiento farmacológico , Tiofenos/farmacología , Animales , Osteocalcina/metabolismo , Osteopontina/metabolismo , Osteoprotegerina/metabolismo , Ovariectomía , Ligando RANK/metabolismo , Ratas , Ratas WistarRESUMEN
Cuscuta chinensis Lam. (Convolvulaceae) is an important herbal medicine widely used to improve sexual function, treat osteoporosis, and prevent aging, and has been reported to exhibit anti-osteoporotic effects in vitro. However, the activity of Cuscuta chinensis Lam. on glucocorticoid-induced osteoporosis still remains unclear. The present study aimed to assess the protective effect and the underlying mechanism of action of Cuscuta chinensis extract (CCE) against glucocorticoid-induced osteoporosis in vivo. Sprague-Dawley rats were randomly divided into four groups as follows: control group, osteoporosis group, and 2 CCE-treated osteoporosis groups (100 mg·kg-1·day-1). Blood samples and femur bones were collected for immunohistochemistry, biochemical, mRNA expression, and western blot analysis. HPLC analysis revealed that chlorogenic acid, quercetin, and hyperin were the major constituents of CCE. The results indicated that CCE increased bone length, bone weight, and bone mineral density and suppressed dexamethasone (DEX)-induced reduction in body weight. In addition, TRAP staining indicated that CCE reduced osteoclasts in DEX-induced osteoporosis rats. Mechanistically, CCE treatment alleviated the increase of bone resorption markers and the decline of osteogenic markers, which might be partially mediated by regulation of RANKL/OPG and RunX2 pathways. These results suggest that CCE showed promising effects in the protection against glucocorticoid-induced osteoporosis through protecting osteoblasts and suppressing osteoclastogenesis.
Asunto(s)
Cuscuta/química , Dexametasona/farmacología , Glucocorticoides/farmacología , Osteoporosis/prevención & control , Osteoprotegerina/metabolismo , Extractos Vegetales/farmacología , Ligando RANK/metabolismo , Animales , Western Blotting , Densidad Ósea/efectos de los fármacos , Cromatografía Líquida de Alta Presión , Inmunohistoquímica , Osteoporosis/inducido químicamente , Osteoprotegerina/efectos de los fármacos , Ligando RANK/efectos de los fármacos , ARN Mensajero , Ratas , Ratas Sprague-DawleyRESUMEN
Background: Thyrotoxicosis increases bone turnover, resulting in net bone loss. Sympathetic nervous system (SNS) activation, via ß2-adrenoceptor (ß2-AR) signaling, also has osteopenic effects. Because thyroid hormones (TH) interact with the SNS to regulate several physiological processes, we hypothesized that this interaction also occurs to regulate bone mass. Previous studies support this hypothesis, as α2-AR knockout (KO) mice are less susceptible to thyrotoxicosis-induced osteopenia. Here, we evaluated whether TH-SNS interactions in bone involve ß2-AR signaling. Methods: Thyrotoxicosis was induced in 120-day-old female and male mice with ß2-AR gene inactivation (ß2-AR-/-) by daily treatment with supraphysiological doses of triiodothyronine (T3) for 12 weeks. The impact of thyrotoxicosis on femoral bone microarchitecture, remodeling, fracture risk, and gene expression of the receptor activator of nuclear factor-kappa-B (RANK)-RANK ligand (RANKL)-osteoprotegerin (OPG) pathway was evaluated. In addition, the effect of the ß2-AR-specific agonist clenbuterol (CL) on cAMP accumulation was determined in osteoblastic (MC3T3-E1) cells treated with T3 and/or 17ß-estradiol (E2). Results: Thyrotoxicosis negatively affected trabecular bone microarchitecture in wild-type (WT) females, but this effect was milder or nonexistent in ß2-AR-/- animals, whereas the opposite was seen in males. T3 treatment increased the femoral RANKL/OPG mRNA ratio and the endosteal perimeter and medullary area of the diaphysis in WT females and males, but not in ß2-AR-/- mice, suggesting that T3 promotes endosteal resorption in cortical bone, in a mechanism that involves ß2-AR signaling. T3 treatment increased endocortical mineral apposition rate only in WT females but not in ß2-AR-/- mice, suggesting that TH also induce bone formation in a ß2-AR signaling-dependent mechanism. T3 treatment decreased femoral resistance to fracture only in WT females, but not in KO mice. E2 and CL similarly increased cAMP accumulation in MC3T3-E1 cells; whereas T3 alone had no effect, but it completely blocked E2-stimulated cAMP accumulation, suggesting that some T3 effects on bone may involve E2/cAMP signaling in osteoblasts. Conclusions: These findings sustain the hypothesis that T3 interacts with the SNS to regulate bone morphophysiology in a ß2-AR signaling-dependent mechanism. The data also reveal sex as an important modifier of skeletal manifestations of thyrotoxicosis, as well as a modifier of the TH-SNS interactions to control bone microarchitecture, remodeling, and resistance to fracture.
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Enfermedades Óseas Metabólicas/metabolismo , Fémur/metabolismo , Receptores Adrenérgicos beta 2/metabolismo , Tirotoxicosis/metabolismo , Agonistas de Receptores Adrenérgicos beta 2/farmacología , Animales , Fenómenos Biomecánicos , Enfermedades Óseas Metabólicas/etiología , Enfermedades Óseas Metabólicas/patología , Enfermedades Óseas Metabólicas/fisiopatología , Remodelación Ósea , Línea Celular , Clenbuterol/farmacología , AMP Cíclico/metabolismo , Estradiol/farmacología , Estrógenos/farmacología , Femenino , Fémur/diagnóstico por imagen , Fémur/patología , Fémur/fisiopatología , Expresión Génica , Masculino , Ratones , Ratones Noqueados , Osteoblastos/efectos de los fármacos , Osteoblastos/metabolismo , Osteoprotegerina/genética , Osteoprotegerina/metabolismo , Ligando RANK/genética , Ligando RANK/metabolismo , Receptor Activador del Factor Nuclear kappa-B/genética , Receptor Activador del Factor Nuclear kappa-B/metabolismo , Receptores Adrenérgicos beta 2/genética , Transducción de Señal , Sistema Nervioso Simpático/metabolismo , Tirotoxicosis/inducido químicamente , Tirotoxicosis/complicaciones , Triyodotironina/farmacología , Triyodotironina/toxicidad , Microtomografía por Rayos XRESUMEN
The pathogenesis of periodontitis involves a complex interaction between the microbial challenge and the host immune response. The individual immunoinflammatory response has a great contribution in the pathogenesis of the disease and becomes a trigger in the process of bone remodeling which is a characteristic of the disease. Thus, the aim of this study was to evaluate the influence of the TLR4 A896G (rs4986790), TLR4 C1196T (rs4986791), CD14 C-260T (rs2569190), RANKL (TNFSF11, rs2277438), and OPG (TNFSF11B C163T, rs3102735) polymorphisms in periodontitis. A case-control study was conducted on patients with periodontitis (N = 203) and controls (N = 213) over 30 years of age, without diabetes mellitus, acute infections, and osteoarthritis, and patients without aggressive periodontitis, i.e., stage IV and C degree of periodontitis, and any periodontal treatment performed in the last 6 months. Genotypes were determined by the PCR-RFLP and sequencing method. The frequency comparisons between case and controls were performed using the chi-square test and logistic regression (OpenEpi and SNPStats software). The risk (OR) was evaluated for values of P < 0.05. Differences in TLR4, CD14, RANKL, and OPG genotype and allele frequency distributions were not observed between patients and controls. However, some variants were a risk factor for the development of periodontitis when considering gender and smoking habits. The TLR4 896 A/G genotype was a risk factor for periodontitis in males (OR = 2.86), and the TLR4 1196C/C genotype was a risk factor for nonsmoking males (OR = 1.85) when compared to women. The RANKL A/A and the OPG T/C genotype was associated with the risk of the disease in nonsmoking men compared to nonsmoking women with the same genotype (OR = 1.96 and OR = 2.9, respectively). In conclusion, TLR4, CD14, RANKL, and OPG variants were not associated with periodontitis. However, TLR4, RANKL, and OPG polymorphisms could be a risk for periodontitis in males regardless of smoking habits.
Asunto(s)
Receptores de Lipopolisacáridos/metabolismo , Osteoprotegerina/metabolismo , Periodontitis/genética , Periodontitis/metabolismo , Polimorfismo Genético/genética , Ligando RANK/metabolismo , Receptor Toll-Like 4/metabolismo , Adulto , Estudios de Casos y Controles , Femenino , Frecuencia de los Genes/genética , Predisposición Genética a la Enfermedad/genética , Genotipo , Humanos , Receptores de Lipopolisacáridos/genética , Masculino , Persona de Mediana Edad , Osteoprotegerina/genética , Ligando RANK/genética , Receptor Toll-Like 4/genéticaRESUMEN
Zoledronic acid (ZOL), a nitrogen bisphosphonate (N-BP), is currently used to treat and control pediatric osteolytic diseases. Variations in the intensity of the effects and side effects of N-BPs have been reported with no clear explanations regarding their origins. We wonder if such variations could be associated with different levels of RANKL signaling activity in growing bone during and after the treatment with N-BPs. To answer this question, ZOL was injected into neonate C57BL/6J mice with different genetically-determined RANKL signaling activity levels (Opg+/+\RankTg-, Opg+/+\RankTg+, Opg+/-\RankTg-, Opg+/-\RankTg+, Opg-/-\RankTg- and Opg-/-\RankTg+ mice) following a protocol (4 injections from post-natal day 1 to 7 at the dose of 50⯵g/kg) that mimics those used in onco-pediatric patients. At the end of pediatric growth (1 and half months) and at an adult age (10â¯months), the bone morphometric and mineral parameters were measured using µCT in the tibia and skull for the different mice. A histologic analysis of the dental and periodontal tissues was also performed. At the end of pediatric growth, a delay in long bone and skull bone growth, a blockage of tooth eruption, some molar root alterations and a neoplasia-like structure associated with incisor development were found. Interestingly, the magnitude of these side effects was reduced by Opg deficiency (Opg-/-) but increased by Rank overexpression (RankTg). Analysis of the skeletal phenotype at ten months confirmed respectively the beneficial and harmful effects of Opg deficiency and Rank overexpression. These results validated the hypothesis that the RANKL signaling activity level in the bone microenvironment is implicated in the modulation of the response to ZOL. Further studies will be necessary to understand the underlying molecular mechanisms, which will help decipher the variability in the effects of N-BPs reported in the human population. SIGNIFICANT STATEMENTS: The present study establishes that in mice the RANKL signaling activity level is a major modulator of the effects and side-effects of bisphosphonates on the individual skeleton during growth. However, the modulatory actions are dependent on the ways in which this level of activity is increased. A decrease in OPG expression is beneficial to the skeletal phenotype observed at the end of growth, while RANK overexpression deteriorates it. Far removed from pediatric treatment, in adults, the skeletal phenotypes initially observed at the end of growth for the different levels of RANKL signaling activity were maintained, although significant improvement was associated only with reductions in OPG expression.