Changes in RANKL, OPG, and 25(OH)D Levels in Children with Leukemia from Diagnosis to Remission.

BACKGROUND: The receptor activator of the nuclear factor-kB (RANK)/RANK ligand (RANKL)/osteoprotegerin (OPG) pathway is a determining pathway in the balance between bone formation and resorption, and disruptions in this complex can affect bone metabolism. METHODS: This study analyzes the changes in RANKL, OPG, and 25(OH)D levels; the RANKL/OPG ratio; and other bone turnover markers (BTMs) from diagnosis to complete remission in children with acute lymphoblastic leukemia (ALL). This is a prospective observational cohort study, carried out at the Instituto Mexicano del Seguro Social, Mexico City, including 33 patients (4-17 years) with newly diagnosed B-cell ALL. The patients were treated with the HP09 chemotherapy protocol. Children who had previously been treated with corticosteroids were excluded. A peripheral blood sample at diagnosis and remission was collected to determine the 25(OH)D and BTM concentrations. RESULTS: Increased RANKL (p = 0.001) and osteocalcin (p < 0.001) levels and RANKL/OPG ratio (<0.001) and a decreased OPG level (p = 0.005) were observed at remission, predominantly in the high-risk (HR) relapse and vitamin D deficiency groups. A negative association between RANKL and OPG (r = -0.454, p = 0.008) was observed. CONCLUSIONS: we suggest that the RANKL/OPG ratio could serve as a bone remodeling marker in ALL patients.

The role of the osteoprotegerin/RANKL/RANK axis and osteopontin in acute coronary syndrome.

Objectives: The primary objective of this study is to ascertain the levels of osteoprotegerin (OPG) and osteopontin (OPN), alongside osteoprotegerin/RANKL ratio (ORR), and assess their association with the SYNTAX score and ascertain the potential of these molecules as predictive markers for risk, aiding in risk stratification. Eventually, they could potentially be employed even before angiography to gauge the severity of coronary lesions. Methods: Prospective study with 147 participants, 101 (69%) were men, with an average age of 60. We included three groups - (1) patients with acute coronary syndrome undergoing percutaneous coronary intervention (ACS-PCI), (2) patients without ACS who underwent coronary angiography for an indication other than ischemia and did not undergo PCI (non-ACS without), and (3) one asymptomatic subject. OPG and OPN were measured. ORR and SYNTAX scores were calculated. The association between OPG and OPN levels and important clinical variables was investigated. Results: OPG levels in Group 1 were lower compared to Groups 2 and 3 (controls), Group 1 (490 pg/mL) versus Group 2 (829 pg/mL) versus Group 3 (845 pg/mL) (p = 0.001). OPG had lower levels in patients with coronary artery stenosis versus without stenosis. A decrease in ORR was shown in all groups and no association with the SYNTAX score. Conclusion: OPG and OPN (and ORR) levels are decreased in patients with ACS and show no correlation with the SYNTAX score. As an exploratory study, our work suggest that increased OPG and OPN levels in non-ACS patients may have, in fact, a protective effect. This study is one of the few with an appropriate control in ACS and reproducibility is necessary mainly with multicenter studies.

Objetivo: El objetivo principal de este estudio es conocer los niveles de OPG y OPN, junto con la ORR, y evaluar su asociación con la puntuación SYNTAX y conocer el potencial de estas moléculas como marcadores predictivos de riesgo, ayudando en la estratificación del riesgo. Con el tiempo, podrían emplearse incluso antes de la angiografía para medir la gravedad de las lesiones coronarias. Métodos: Estudio prospectivo con 147 participantes, 101 (69%) eran hombres, con una edad promedio de 60 años. Se incluyeron tres grupos (1) pacientes con SCA sometidos a ICP (SCA-ICP), (2); pacientes sin SCA sometidos a angiografía coronaria por una indicación distinta a la isquemia y no sometidos a ICP (sin SCA sin) (3) un sujeto asintomático. Se midieron OPG, OPN. Se calcularon las puntuaciones ORR y SYNTAX. Se investigó la asociación entre los niveles de OPG y OPN y variables clínicas importantes. Resultados: Los niveles de OPG en el Grupo 1 fueron más bajos en comparación con los Grupos 2 y 3 (controles). Grupo 1 (490 pg/mL) versus Grupo 2 (829 pg/mL) versus Grupo 3 (845 pg/mL) [p = 0.001]). La OPG tuvo niveles más bajos en pacientes con estenosis de la arteria coronaria versus sin estenosis. Se mostró una disminución en la ORR en todos los grupos y no hubo asociación con la puntuación SYNTAX. Conclusione: Los niveles de OPG OPN (y ORR) están disminuidos en pacientes con SCA y no muestran correlación con la puntuación SYNTAX. Como estudio exploratorio, nuestro trabajo sugiere que los niveles elevados de OPG y OPN en pacientes sin SCA pueden tener, de hecho, un efecto protector. Este estudio es uno de los pocos con un control adecuado en SCA y la reproducibilidad es necesaria principalmente con estudios multicéntricos.

Serum osteoprotegerin and its gene polymorphisms in patients with Takayasu's arteritis: a bicentric cross-sectional study.

INTRODUCTION: Takayasu's arteritis (TAK) patients are at an elevated risk of metabolic syndrome and cardiovascular diseases (CVD). Currently, there are no well-validated biomarkers to assess this risk in this population. Previous research in different cohorts has linked serum levels of osteoprotegerin (OPG) and its polymorphisms to accelerated atherosclerosis and a marker of poor prognosis in CVD. Thus, we assessed this protein as a potential biomarker of CVD in TAK patients. OBJECTIVES: To evaluate the serum levels of OPG and its SNPs (single nucleotide polymorphisms) in TAK patients and healthy controls, and to associate these parameters with clinical data. METHODS: This bicentric cross-sectional study included TAK patients who were compared with healthy individuals (control group). The serum levels of OPG and the frequency of OPG SNPs [1181G > C (rs2073618), 245 A > C (rs3134069), 163T > C (rs3102735), and 209 C > T (rs3134070)] were compared between the both groups and associated with clinical data. RESULTS: In total, 101 TAK patients and 93 controls were included in the study. The serum levels of OPG (3.8 ± 1.9 vs. 4.3 ± 1.8pmol/L, respectively; P = 0.059), and its four polymorphisms were comparable between both groups. In an additional analysis of only TAK patients, serum OPG levels and its four genes were not associated with any CVD parameters, except for higher OPG levels among patients without dyslipidemia. CONCLUSION: No significant differences were observed in serum OPG levels or in the genotype frequencies of OPG SNPs between the patient and control groups. Similarly, no correlation was found between laboratory parameters and clinical data on CVD risk in TAK patients.

Calotropis procera latex protein reduces inflammation and bone loss in ligature-induced period ontitis in male rats.

OBJECTIVE: Calotropis procera latex protein (CpLP) is a popular anti-inflammatory and therefore we aimed to study its effects on inflammatory bone loss. DESIGN: Male Wistar rats were subjected to a ligature of molars. Groups of rats received intraperitoneally CpLP (0.3 mg/kg, 1 mg/kg, or 3 mg/kg) or saline (0.9% NaCl) one hour before ligature and then daily up to 11 days, compared to naïve. Gingiva was evaluated by myeloperoxidase activity and interleukin-1 beta (IL-1ß) expression by ELISA. Bone resorption was evaluated in the region between the cement-enamel junction and the alveolar bone crest. The histology considered alveolar bone resorption and cementum integrity, leukocyte infiltration, and attachment level, followed by immunohistochemistry bone markers between 1st and 2nd molars. Systemically, the weight of the body and organs, and a leukogram were performed. RESULTS: The periodontitis significantly increased myeloperoxidase activity and the IL-1ß level. The increased bone resorption was histologically corroborated by periodontal destruction, leukocyte influx, and attachment loss, as well as the increasing receptor activator of the nuclear factor-kappa B ligand (RANKL)/osteoprotegerin (OPG) ratio, and Tartrate-resistant acid phosphatase (TRAP)+ cells when compared to naïve. CpLP significantly reduced myeloperoxidase activity, level of IL-1ß, alveolar bone resorption, periodontal destruction, leukocyte influx, and attachment loss. The CpLp also reduced the RANKL/OPG ratio and TRAP+ cells, when compared with the saline group, and did not affect the systemic parameters. CONCLUSIONS: CpLP exhibited a periodontal protective effect by reducing inflammation and restricting osteoclastic alveolar bone resorption in this rat model.

Evaluation of Receptor Activator of Nuclear Factor Kappa B Ligand, Osteoprotegerin, Osteopontin, and Tumor Necrosis Factor Alpha on Chronic Apical Periodontitis in Smokers.

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.

Duchenne muscular dystrophy: RANK/RANKL/OPG (receptor activator of nuclear factor-kB/RANK ligand/osteoprotegerin) system and glucocorticoids.

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.

Lithium chloride stimulates bone formation in extraction socket repair in rats.

PURPOSE: Previous evidence shows that lithium chloride (LiCl), a suppressor of glycogen synthase kinase-3ß (GSK-3ß), may enhance bone formation in several medical and dental conditions. Thus, the purpose of the current study was to assess the effects of LiCl on extraction socket repair in rats. METHODS: Thirty rats were randomly assigned into a control group (administration of water; n = 15) or a LiCl group (administration of 150 mg/kg of LiCl; n = 15). LiCl and water were given every other day, starting at 7 days before the extraction of upper first molars until the end of each experiment period. Histological sections from five rats per group were obtained at 10, 20, and 30 days post-extractions. Histometrical analysis of newly formed bone (NB) and the levels of tartrate-resistant acid phosphatase (TRAP)-stained cells were evaluated at 10, 20, and 30 days post-extractions. Immunohistochemical staining for receptor activator of nuclear factor kappa-Β ligand (RANKL), osteoprotegerin (OPG), bone sialoprotein (BSP), osteocalcin (OCN), and osteopontin (OPN) was assessed at 10 days post-extractions. RESULTS: The LiCl group had a greater proportion of NB than the control group at 20 days (P < 0.05). At 30 days, the rate of TRAP-stained cells was lower in the LiCl group than in the control group (P < 0.05). At 10 days, the LiCl group presented stronger staining for OPG, BSP, OPN, and OCN, when compared to the control group (P < 0.05). CONCLUSION: Systemic LiCl enhanced extraction socket repair, stimulated an overall increase in bone formation markers, and restricted the levels of TRAP in rats.

Duchenne muscular dystrophy: RANK/RANKL/OPG (receptor activator of nuclear factor-kB/RANK ligand/osteoprotegerin) system and glucocorticoids / Distrofia muscular de Duchenne: el sistema RANK/RANKL/OPG (receptor activador del factor nuclear-kB/ligando de RANK/osteoprotegerina) y glucocorticoides

Abstract 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.

Resumen 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.

Molecular Biomarkers in Peri-Implant Health and Disease: A Cross-Sectional Pilot Study.

BACKGROUND: The aim of this feasibility study was to investigate the concentration level of CCL-20/MIP-3α, BAFF/BLyS, IL-23, RANKL, and Osteoprotegerin in the Peri-Implant Crevicular Fluid (PICF), from patients diagnosed with peri-implant mucositis and peri-implantitis, and to compare them with PICF from patients with healthy implants. METHODS: Participants with at least one dental implant with healthy peri-implant tissues, peri-implant mucositis, or peri-implantitis were included. PICF was collected using paper strips from healthy and diseased peri-implant sites (n = 19). Biomarker levels were analyzed using a custom Multiplex ELISA Assay Kit. RESULTS: In comparison to peri-implant health, the peri-implant mucositis group showed an increased concentration of CCL-20 MIP-3α, BAFF/BLyS, IL-23, RANKL, and Osteoprotegerin. The peri-implantitis group had the lowest median concentration of Osteoprotegerin (1963 ng/mL); this group had a similar concentration of RANKL (640.84 ng/mL) when compared to the peri-implant health group. BAFF/BLyS (17.06 ng/mL) showed the highest concentration in the peri-implantitis group. CONCLUSIONS: This feasibility study suggests that IL-23 and RANKL may help to elucidate the pathogenesis during the conversion from peri-implant health to peri-implantitis. Further research is required in BAFF/BLyS for the early diagnosis of peri-implantitis.

Osteoprotegerin Gene Polymorphisms Are Associated with Subclinical Atherosclerosis in the Mexican Mestizo Population.

Subclinical atherosclerosis (SA) is the presence of coronary calcification in the absence of cardiovascular symptoms, and it usually progresses to atherosclerotic disease. Studies have shown an association of osteoprotegerin gene (OPG) variants with calcification process in cardiovascular diseases; however, to this day there are no studies that evaluate individuals in the asymptomatic stage of atherosclerotic disease. Therefore, the purpose of this study was to analyze the association of four genetic variants and haplotypes of the OPG gene with the development of SA, through TaqMan genotyping assays. We also aimed to identify potential response elements for transcription factors in these genetic variants. The study included 1413 asymptomatic participants (1041 were controls and 372 were individuals with SA). The rs3102735 polymorphism appeared as a protective marker (OR = 0.693; 95% CI = 0.493−0.974; pheterozygote = 0.035; OR = 0.699; 95% CI = 0.496−0.985; pcodominant 1 = 0.040) and two haplotypes were associated with SA, one as a decreased risk: GACC (OR = 0.641, 95% CI = 0.414−0.990, p = 0.045) and another as an increased risk: GACT (OR = 1.208, 95% CI = 1.020−1.431, p = 0.029). Our data suggest a lower risk of SA in rs3102735 C carriers in a representative sample of Mexican mestizo population.

Osteoprotegerin Is a Better Predictor for Cardiovascular and All-Cause Mortality than Vascular Calcifications in a Multicenter Cohort of Patients on Peritoneal Dialysis.

The purpose of this study was to compare vascular calcification (VC), serum osteoprotegerin (OPG) levels, and other biochemical markers to determine their value as available predictors of all-cause and cardiovascular (CV) mortality in patients on peritoneal dialysis (PD). A total of 197 patients were recruited from seven dialysis centers in Mexico City. VC was assessed with multi-slice computed tomography, measured using the calcification score (CaSc). OPG, albumin, calcium, hsC-reactive protein, phosphorous, osteocalcin, total alkaline phosphatase, and intact parathormone were also analyzed. Follow-up and mortality analyses were assessed using the Cox regression model. The mean age was 43.9 ± 12.9 years, 64% were males, and 53% were diabetics. The median OPG was 11.28 (IQR: 7.6−17.4 pmol/L), and 42% of cases had cardiovascular calcifications. The median VC was 424 (IQR:101−886). During follow-up (23 ± 7 months), there were 34 deaths, and 44% were cardiovascular in origin. In multivariable analysis, OPG was a significant predictor for all-cause (HR 1.08; p < 0.002) and CV mortality (HR 1.09; p < 0.013), and performed better than VC (HR 1.00; p < 0.62 for all-cause mortality and HR 1.00; p < 0.16 for CV mortality). For each mg/dL of albumin-corrected calcium, there was an increased risk for CV mortality, and each g/dL of albumin decreased the risk factor for all-cause mortality. OPG levels above 14.37 and 13.57 pmol/L showed the highest predictive value for all-cause and CV mortality in incident PD patients and performed better than VC.

Quantification of Osteoprotegerin Plasma Levels in Patients with Periodontitis.

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.

Pulpal outcomes in orthodontic tooth movement in diabetes mellitus.

Diabetes mellitus impairs angiogenesis and tissue reorganization during orthodontic tooth movement (OTM). Thus, this study evaluated pulpal outcomes in orthodontic tooth movement through metabolic changes in diabetes. Male Wistar rats were used, and the in vivo study design consisted of four groups (n = 10/group): C-non-diabetic animals not subjected to orthodontic tooth movement; D-diabetic animals not subjected to orthodontic tooth movement; OTM-non-diabetic animals subjected to orthodontic tooth movement; and D + OTM-diabetic animals subjected to orthodontic tooth movement. In addition, the pulps of the distovestibular root (DV) and mesiovestibular root (MV) were assessed by histomorphometric analyses and immunoexpression of the RANKL/OPG system. Pulpal analysis of the MV root showed an increase in blood vessels in diabetic animals. Inflammatory infiltrate and fibroblastic cells were elevated in diabetic animals with tooth movement in the DV and MV roots. In the DV and MV roots, diabetic rats with OTM showed a reduction in birefringent collagen fibers. The immunostaining for RANKL was higher in the pulp tissue of OTM in diabetic and non-diabetic animals. It was concluded that the pulp tissue has less adaptive and repair capacity during OTM in diabetes. Orthodontic strength can alter the inflammatory processes in the pulp.

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

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

Gestational protein restriction alters the RANKL/OPG system in the dental germ of offsprings.

Evaluate the dentinogenesis in the offspring of rats submitted to gestational protein restriction (GPR). DESIGN: The offspring were evaluated at the 21st day of gestation (21 dG). Assessments were made of morphological parameters and the RANKL/OPG system - bone tissue maturation markers - in the upper incisor tooth germ. Pregnant 10-week-old female Wistar rats were divided into normal protein (NP, 17% casein, n = 5) and low protein (LP, 6% casein, n = 5) diet groups. At 21 dG, the offspring maxillae were collected for histomorphometric and immunohistochemical analyses. RESULTS: The LP group showed decreased thickness of the dentin and odontoblast cell layers on the tooth germ. GPR led to decreased OPG expression and increased RANKL expression in the incisor germ. CONCLUSION: The results suggested that gestational protein restriction altered odontoblast RANKL/OPG expression and decreased dentin matrix deposition and thickness in tooth development.

Genetic Variants and Haplotypes in OPG Gene Are Associated with Premature Coronary Artery Disease and Traditional Cardiovascular Risk Factors in Mexican Population: The GEA Study.

Basic and clinical research have demonstrated that osteoprotegerin (OPG) plays an important role in the development and progression of cardiovascular diseases. The aim of this study was to evaluate the association of four polymorphic sites (rs2073618, rs3134069, rs3134070, and rs3102735) of OPG gene with premature coronary artery disease (pCAD), and with cardiometabolic parameters. The polymorphisms were genotyped using 5' exonuclease TaqMan genotyping assays with real-time PCR in 1098 individuals with pCAD and 1041 healthy controls. rs2073618 polymorphism was associated with a high risk of developing pCAD according to different inheritance models: additive (p = 0.001; odds ratio [OR] = 1.283), dominant (p = 0.006; OR = 1.383), recessive (p = 0.011; OR = 1.423), and codominant 2 (p = 0.001; OR = 1.646). The four polymorphisms were associated with different cardiovascular risk factors in individuals with pCAD and controls. Our results suggest that OPG rs2073618 polymorphism is associated with an increased risk of pCAD. In addition, two haplotypes were associated with pCAD, one increasing the risk (CACT) and another one as protective (GACC).

Effects of strontium ranelate on ligature-induced periodontitis in estrogen-deficient and estrogen-sufficient rats.

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-КB 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.

Lithium chloride assuages bone loss in experimental periodontitis in estrogen-deficient rats.

OBJECTIVES: Evidence shows that lithium, a medication commonly used for bipolar disorder treatment, presents bone anabolic activity. This study evaluated the effects of lithium chloride on periodontitis-induced bone loss (BL) and on intact alveolar bone during estrogen sufficiency and deficiency. MATERIALS AND METHODS: Rats (24/group) received sham surgery plus water (estrogen-sufficient group), ovariectomy plus water (estrogen-deficient group), sham surgery plus lithium chloride (150 mg/kg/every other day) (lithium/estrogen-sufficient group), or ovariectomy plus lithium chloride (lithium/estrogen-deficient group). One first mandibular molar received ligature, while the contralateral molar was left unligated. BL and trabecular bone area (TBA) were assessed in the furcation bone at 10, 20, and 30 days after ligature placement. Histochemical staining for TRAP and immunohistochemical staining for osteocalcin, osteopontin, osteoprotegerin, and RANKL were evaluated at 30 days after ligature placement. RESULTS: At 10 days, the estrogen-deficient group presented the highest BL (0.115 ± 0.026), while the lithium/estrogen-deficient group (0.048 ± 0.024) presented the lowest BL in the ligated teeth (p < 0.05). At 20 and 30 days, the estrogen-deficient group exhibited significantly higher BL than all the other groups (p < 0.05). The ligated teeth of the lithium/estrogen-sufficient group presented the highest TBA while those of the estrogen-deficient group presented the lowest TBA at 10 and 30 days (p < 0.05). Unligated teeth of lithium-treated groups had stronger staining for osteocalcin and osteopontin than the estrogen-deficient group (p < 0.05). Ligated and unligated teeth of the estrogen-deficient group exhibited lower expression of osteoprotegerin than the other groups (p < 0.05). Lithium-treated groups exhibited generally higher staining of RANKL than the untreated groups (p < 0.05). Unligated teeth in both estrogen-sufficient groups presented lower TRAP expression than both estrogen-deficient groups (p < 0.05). CONCLUSIONS: Lithium chloride reduced ligature-induced BL in estrogen-deficient rats and yielded an overall greater trabecular area and overexpression of bone markers in alveolar bone under normal and deficient estrogen states. CLINICAL RELEVANCE: Lithium chloride may be a promising agent to assuage alveolar bone loss related to periodontitis, especially in osteoporotic conditions.

Effect of enhanced masticatory force on OPG, RANKL and MGF in alveolar bone of ovariectomized rats

Abstract Menopause induces oral bone loss, leading to various oral diseases. Mastication importantly affects bone metabolism in the jawbone. Objective: To analyze the effect of enhanced masticatory force on osteoprotegerin (OPG), receptor activator of nuclear factor kappa B ligand (RANKL), and mechano-growth factor (MGF) in alveolar bone of ovariectomized rats and to study the mechanics mechanism of the alveolar bone of ovariectomized rats response to enhanced masticatory force. Methodology: Thirty Sprague Dawley rats were randomly divided into three groups: sham-operation group (fat around the removed ovary + normal hard diet), model group (ovariectomy + normal hard diet), and experimental group (ovariectomy + high hard diet). It was a 2-month experiment. Enzyme-linked immunosorbent assay (ELISA) detected serum estradiol (E2), osteocalcin (BGP) and alkaline phosphatase (ALP) in rats. Bone histomorphometric indices in the third molar region of maxilla were detected by micro-CT; protein expressions of OPG, RANKL, and MGF in the third molar region of maxilla was detected by Western blot; and gene expression of OPG, RANKL, and MGF in the third molar region of maxilla was detected by Quantitative Real-Time PCR. Results: Comparing with model group, serum E2 in experimental group increased but not significantly, serum BGP and serum ALP in experimental group decreased but not significantly, OPG in experimental group in alveolar bone increased significantly, RANKL in experimental group in alveolar bone decreased significantly, RANKL/OPG ratio in experimental group decreased significantly, MGF in experimental group in alveolar bone increased significantly, bone volume to total volume fraction increased significantly in experimental group, trabecular thickness increased significantly in experimental group, and trabecular separation decreased significantly in experimental group. Conclusion: Enhanced masticatory force affected the expression of OPG, RANKL, and MGF in alveolar bone of ovariectomized rats, improved the quality of jaw bone of ovariectomized rats, and delayed oral bone loss by ovariectomy.

Cholecalciferol supplementation increases FGF23 in peritoneal dialysis patients with hypovitaminosis D: a randomized clinical trial.

BACKGROUND: Vitamin D deficiency is common in peritoneal dialysis (PD) patients, so its supplementation has been advocated as potentially beneficial. METHODS: Double-blind, placebo-controlled, randomized clinical trial. Subjects on PD treated with high calcium peritoneal dialysate (Ca 3.5 mEq/l) and serum levels of 25-hydroxi vitamin D (25D) < 20 ng/ml were randomized to receive cholecalciferol (4800 IU/daily) or placebo for 16 weeks. The outcome measures were the effects on the osteogenic biomarkers osteoprotegerin (primary endpoint), intact fibroblast growth factor-23 (iFGF23), osteocalcin, osteopontin, iPTH, 1,25-dyhydroxivitamin D (1,25D), and interleukin-6. RESULTS: Fifty-eight subjects were randomly assigned. Baseline characteristics were similar in both groups. Cholecalciferol supplemented subjects had a significant increase in serum 25D (from 11.4 ± 5.0 to 28.3 ± 10.3 ng/ml), 1,25D and iFGF23 compared with placebo group. iFGF23 levels increased an average of 10,875 pg/ml per month (95% CI 11,778-88,414) in the cholecalciferol group and was unchanged in the placebo group (2829 pg/ml, 95% CI - 2181 to 14,972). Extremely high iFGF23 levels (> 30,000 pg/ml) were observed in 74% of subjects receiving cholecalciferol although iFGF23 returned to baseline values after 32 weeks of withdrawal. The observed changes in iFGF23 correlated with 1,25D levels and were not modified by other variables. No difference was observed between groups in osteoprotegerin or other osteogenic biomarkers levels. CONCLUSIONS: Cholecalciferol supplementation increases serum 25D levels in subjects on PD exposed to high calcium dialysate, yet it induces an exponential increase of iFGF23 in most patients, which disappear after withdrawal of supplementation and may be a major concern for this maneuver.