Evaluation of RANK/RANKL/OPG gene polymorphisms in aggressive periodontitis

BACKGROUND AND OBJECTIVE: Aggressive periodontitis (AgP) is a specific type of periodontal disease that is characterized by rapid attachment loss and bone destruction. While attempting to identify genetic polymorphisms associated with AgP, previous research has focused on candidate genes that may be involved in immune responses to microbial infections. In this study, the focus was on single nucleotide polymorphisms (SNPs) in the key mediators of osteoclast differentiation and activation, which involve receptor activator of nuclear factor-kappaB (RANK), RANK ligand (RANKL) and osteoprotegrin (OPG), in the Japanese population. The aim of this study was to evaluate the association of RANK/RANKL/OPG gene polymorphisms with AgP in the Japanese population. MATERIAL AND METHODS: We examined 99 patients with AgP and 89 controls from the Japanese population to explore the possibility of RANK/RANKL/OPG loci as candidate regions associated with the disease. All exons and relevant exon-intron boundaries of these three candidate genes were amplified by polymerase chain reaction (PCR) using 19 primers, followed by direct sequencing. The polymorphisms were identified by comparing the sequences obtained from 48 subjects. RESULTS: We identified 27 SNPs in RANK, including 10 novel SNPs and seven SNPs each in both RANKL and OPG. A pairwise linkage disequilibrium analysis using the r2 statistic showed that some SNP pairs from the three loci are in tight linkage disequilibrium. CONCLUSION: An association analysis with allelotypes showed that SNPs identified in the RANK/RANKL/OPG genes have no significant association with AgP in the Japanese population.     

Design of electrospun nanofibrous mats for osteogenic differentiation of mesenchymal stem cells

The clinical translation potential of mesenchymal stem cells (MSCs) in regenerative medicine has been greatly exploited. With the merits of high surface area to volume ratio, facile control of components, well retained topography, and the capacity to mimic the native extracellular matrix (ECM), nanofibers have received a great deal of attention as bone tissue engineering scaffolds. Electrospinning has been considered as an efficient approach for scale-up fabrication of nanofibrous materials. Electrospun nanofibers are capable of stimulating cell–matrix interaction to form a cell niche, directing cellular behavior, and promoting the MSCs adhesion and proliferation. In this review, we give a comprehensive literature survey on the mechanisms of electrospun nanofibers in supporting the MSCs differentiation. Specifically, the influences of biological and physical osteogenic inductive cues on the MSCs osteogenic differentiation are reviewed. Along with the significant advances in the field, current research challenges and future perspectives are also discussed.     

High osteoprotegerin levels predict MACCE in STEMI patients,but are not associated with myocardial salvage

Objectives. High circulating levels of osteoprotegerin (OPG) carry prognostic impact in cohorts with various cardiovascular diagnoses. With the present study, we aim to investigate the role of OPG within the scale of myocardial damage. Design. This study includes 219 consecutive patients with acute ST-elevation myocardial infarction randomized to primary percutaneous coronary intervention (pPCI) or pPCI and remote ischemic per-conditioning. Salvage index via myocardial single-photon emission CT assessment (data available in 61% of the patients) was performed, and derived from Day 1 (myocardial area at risk) and Day 30 (final infarct size). Plasma OPG levels were measured using an in-house immunoassay. A combined end-point of all-mortality, myocardial infarction, stroke, readmission for heart failure and ischemic stroke/transient ischemic attack (Major Adverse Cardiac and Cerebrovascular Events [MACCE]) was used for follow-up; 45 (38–48 months). Results. High OPG levels were associated with the severity of cardiovascular disease. During follow-up, OPG was a predictor of MACCE (unadjusted, HR: 2.1, 95% CI: 1.14–3.85, P = 0.017). Adjustments for age, gender, and body mass index preserved the independent predictive power of OPG. However, OPG levels were neither associated with salvage index nor with the final infarct size. Remote ischemic per-conditioning had no effect on OPG levels. Conclusion. Despite absent association between OPG levels and the scale of myocardial damage, high OPG levels predict a significantly increased risk of MACCE.     

Are OPG and RANKL involved in human fracture healing?

Human fracture healing is a complex interaction of several cytokines that regulate osteoblast and osteoclast activity. By monitoring OPG (osteoprotegerin) and sRANKL we aimed to possibly predict normal or impaired fracture healing. In 64 patients with a fracture of a long bone serum level of sRANKL and OPG were evaluated with respect to bony union (n = 57) or pseudarthrosis (n = 7). Measurements were carried out at admission and at 1, 2, 4, 6, 8, 12, 24, and 48 weeks after the injury. Patients' serum levels were compared to 33 healthy controls. Fracture hematoma contained significantly higher sRANKL and OPG concentrations compared to patients serum (p = 0.005, p = 0.028). OPG level in fracture hematoma was higher compared to the unions serum level (p = 0.028). sRANKL was decreased in unions during the observation period. In non‐unions sRANKL and OPG levels showed a variable course, with no statistical significance. This is the first study to document the course of OPG and sRANKL in normal and delayed human fracture healing emphasizing its local and systemic involvement. We provide evidence of strongly enhanced OPG levels in patients with a long bone fracture compared to healthy controls. Further, levels of free sRANKL were decreased during regular fracture repair. © 2014 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 32:1557–1561, 2014.     

Bisphosphonates Inhibit Osteosarcoma‐Mediated Osteolysis Via Attenuation of Tumor Expression of MCP‐1 and RANKL

Osteosarcoma is the most common primary malignant tumor of bone and accounts for around 50% of all primary skeletal malignancies. In addition to novel chemotherapies, there is a need for adjuvant therapies designed to inhibit osteosarcoma proliferation and tumor‐induced osteolysis to attenuate tumor expansion and metastasis. As such, studies on the efficacy of bisphosphonates on human osteosarcoma are planned after feasibility studies determined that the bisphosphonate zoledronic acid (ZOL) can be safely combined with conventional chemotherapy. However, the molecular mechanisms responsible for, and means of inhibiting, osteosarcoma‐induced osteolysis are largely unknown. We establish that osteosarcoma growth directly correlates with tumor‐induced osteolysis and activation of osteoclasts in vivo. In vitro, tumor cells were determined to expresses surface, but not soluble, receptor activator of NF‐κB ligand (RANKL) and stimulated osteoclastogenesis in a manner directly proportional to their malignant potential. In addition, an aggressive osteosarcoma cell line was shown to secrete monocyte chemoattractant protein‐1 (MCP‐1), resulting in robust monocyte migration. Because MCP‐1 is a key cytokine for monocyte recruitment and surface‐bound RANKL strongly supports local osteoclastogenesis, we suggest that high levels of these signaling molecules are associated with the aggressive potential of osteosarcoma. Consistent with these findings, abundant expression of RANKL/MCP‐1 was observed in tumor in vivo, and MCP‐1 plasma levels strongly correlated with tumor progression and osteolysis. ZOL administration directly attenuates osteosarcoma production of RANKL/MCP‐1, reducing tumor‐induced bone destruction. In vivo, these findings also correlated with significant reduction in osteosarcoma growth. ZOL attenuates tumor‐induced osteolysis, not only through direct inhibition of osteoclasts, but also through direct actions on tumor expression of osteoclast activators. These data provide insight regarding the effect of ZOL on osteosarcoma essential for designing the planned upcoming prospective randomized trials to determine the efficacy of bisphosphonates on osteosarcoma in humans. © 2014 American Society for Bone and Mineral Research.     

大鼠正畸牙移动过程中白介素-10对RANKL／OPG因子表达的影响

目的研究白细胞介素-10（IL-10）在大鼠正畸牙移动进程中,对核因子KB配体受体激活子（RANKL）／护骨素（OPG）表达的影响。方法SD大鼠32只随机分为对照组（局部注射PBS缓冲液圾实验组各16只,实验组分为4个小组,每小组4只,局部注射IL～10,剂量分别为0．4μg／mL、0．8μg／mL、0．16μg／mL、0．032μg／mL;应用免疫组织化学染色法及ELISA法分析牙周组织中的RANKL及牙周膜细胞中的OPG的表达情况。结果与对照组及0．032μg／mL组相比,4μg／mL、0.8μg／mL、0．16μg／mL各小组RANKL的阳性表达面积比显著降低;而OPG（4μg／mL）组呈现出逐渐增加的趋势。结论IL—10能抑制牙周组织RANKL的表达及增加大鼠牙周膜细胞OPG表达,减弱破骨／破牙骨质细胞的作用。     

Microcrack surface density in the human otic capsule: An unbiased stereological quantification

Bone is continuously remodeled to repair and strengthen degenerative bone with accumulating dead osteocytes and microfractures. Inner ear osteoprotegerin (OPG)-mediated inhibition of otic capsular bone remodeling causes excessive perilabyrinthine bone degeneration. Consequently, microcracks accumulate around the inner ear. Microcracks cause osteocyte apoptosis and may disrupt the canalicular network connecting osteocytes. Despite their linear microscopic appearance, microcracks are three-dimensional disruption planes and represent surface areas inside a tissue space. With an elevated microcrack burden the number of disconnected osteocytes is expected to increase. This may prove relevant to ongoing research in otic focal pathologies like otosclerosis. Therefore, an unbiased quantification of the microcrack surface density (mm²/mm³) in the human otic capsule is essential. In this study unbiased stereology was applied to undecalcified bulk stained human temporal bones to demonstrate its feasibility in describing the three-dimensional reality behind two dimensional observations of microcracks. A total of 28 human temporal bones and five ribs were bulk stained in basic fuchsin, serially sectioned and hand-ground to a thickness of 80–120 μm. Both horizontal and vertical sections were produced and compared. This study showed that surface density of microcracks was significantly higher around the inner ear compared to ribs. Furthermore, no significant difference in microcrack surface density between horizontal and vertical sections in the temporal bone was demonstrated.     

Meeting Report

Abstract

The aim of the investigation was to evaluate which radiographic factors influenced the orthodontists' decision whether to expose or remove an impacted upper permanent canine and was a retrospective, cross-sectional design. The sample consisted of all radiographic records of patients referred to the Orthodontic Department at Manchester University Dental Hospital with impacted upper permanent canines between 1994–1998 (n = 44). The following canine position measurements were made from the OPG: angulation to the midline, vertical height, antero-posterior position of the root, overlap of the adjacent incisor, and presence of root resorption of adjacent incisor(s). The labio-palatal position of the impacted canine was assessed from the lateral skull radiograph. Whether the impacted canine had been exposed and orthodontically aligned or removed was also recorded.

Stepwise logistic regression analysis showed that the labio-palatal position of the crown influenced the treatment decision, with palatally positioned impacted canines more likely to be surgically exposed and those in the line of the arch, or labially situated, removed (P < 0?05). Additionally, as the canine angulation to the midline increased, the canine was more likely to be removed (P < 0?05).

The orthodontists' decision to expose or remove an impacted upper permanent canine, based on radiographic information, seems to be primarily guided by two factors: labio-palatal crown position and angulation to the midline.     

补骨脂素对成骨细胞核因子-κB受体激活配体和骨保护素表达的影响

目的研究补骨脂素(psoralen,PSO)对体外培养的小鼠成骨细胞(OB)分化及核因子-κB受体激活配体(receptor activator of nuclearfactor-κB ligand,RANKL)和骨保护素(osteoprotegerin,OPG)表达的影响。方法取第1代BALB/c小鼠颅盖骨成骨细胞,将PSO以0.1、1、10μmol/L3种浓度分别加入新生大鼠颅骨成骨细胞培养液中,MTT法观察各组药物对成骨细胞的增殖作用并绘制细胞生长曲线;用PNPP法测定成骨细胞内碱性磷酸酶(alkaline phosphatase,ALP)活性;RT-PCR法检测成骨细胞OPG和RANKL的转录水平。结果细胞生长曲线显示各组成骨细胞数量均随时间延长而增加,中、高浓度PSO能显著提高成骨细胞的ALP活性,促进OPG、RANKL的表达(P<0.05),OPG/RANKL升高(P<0.05)。结论低浓度PSO(0.1μmol/L)对骨更新作用不明显,而中、高浓度PSO(1、10μmol/L)能通过上调OPG、RANKL mRNA表达及OPG/RANKL比例,促进成骨细胞的生成功能,增强骨更新。     

拉莫德对类风湿关节炎继发骨质疏松的治疗作用及相关机制

目的探讨艾拉莫德对类风湿关节炎（RA）继发骨质疏松（OP）的治疗作用及相关机制。方法选取诊断明确的RA患者90例,按随机数字表法,将患者随机分为对照组45例和观察组45例,对照组采用甲氨蝶呤片（MTX）联合羟氯喹片(HCQ)治疗,观察组采用在MTX、HCQ基础上加用艾拉莫德治疗,两组患者药物治疗观察期均为24周,比较两组患者治疗前后的关节压痛数（TJC）、关节肿胀数（SJC）、血沉（ESR）、C反应蛋白（CRP）、视觉模拟评分法（VAS）(患者总体评价)、28个关节疾病活动度（DAS28）、骨密度（BMD）、总Ⅰ型胶原氨基端延长肽（TPINP）、β-胶原降解产物（β-CTX）、肿瘤坏死因子-α（TNF-α）、白细胞介素-6（IL-6）、骨保护素（OPG）、核因子κB受体活化因子配体（RANKL）,观察两组患者不良反应发生率。结果（1）两组治疗24周后,ESR、CRP、VAS、DAS28均较治疗前改善（P<0.05）,但观察组较对照组改善更显著（P<0.05）;（2）治疗24周后,各部位骨密度值观察组均高于对照组,但两组骨密度水平差异无统计学意义（P>0.05）,观察组较对照组TPINP升高、β-CTX降低更显著（P<0.05）;（3）治疗24周后,IL-6、TNF-α均降低,且观察组均低于对照组（P<0.05）,OPG均较治疗前升高,RANKL均较治疗前降低,但观察组OPG水平高于对照组,RANKL水平低于对照组（P<0.05）;（4）未有患者发生严重不良事件,两组患者不良反应发生率比较差异无统计学意义（P>0.05)。结论（1）艾拉莫德联合用药能够更有效地减轻RA患者的疾病活动,改善临床症状,而且未增加不良反应;（2）艾拉莫德联合用药能够更显著地调节骨代谢、改善骨密度,可能通过影响OPG/RANK/RANKL系统。