RANKL-OPG在口腔中表达的研究进展

破骨细胞生成因子（RANKL）/骨保护素（OPG）系统是影响破骨细胞分化、发育、调节的重要信号通路,也是全身因子和局部因子调节骨代谢的共同通路[1]。在口腔医学领域中,RANKL/OPG系统也起到相当重要的作用,本文就RANKL/OPG系统在口腔中表达的研究进展作一综述。     

流体剪切力对MC3T3-E1细胞OPG、RANKL蛋白表达的实验研究

目的探讨流体剪切力(fluid shear stress,FSS)作用下,两种调节骨骼重建的重要分子骨保护素(osteoprotegerin,OPG)和细胞核因子κB受体活化因子配体(receptor activator of NF-κB ligand,RANKL)的蛋白表达情况。方法采用体外模型对MC3T3-E1细胞加载流体剪切力,细胞经不同时间加力后(0,30,60,90,120min),对细胞分别进行染色和裂解,运用免疫荧光和蛋白印迹法对OPG和RANKL的蛋白表达水平进行定量分析。结果 FSS作用30,60,90,120min后能够显著增加OPG的蛋白表达(P0.05),减少RANKL的蛋白表达(P0.05)。两者共同作用使得OPG/RANKL值显著增高(P0.05)。结论流体剪切力刺激提示OPG/RANKL的比值可能在成骨细胞和破骨细胞联合调节骨骼形成和吸收的过程中起着重要的调节作用。     

Changes in the serum sex steroids, IL-7 and RANKL-OPG system after bone marrow transplantation: influences on bone and mineral metabolism

This study prospectively investigated the changes of the serum levels of the sex steroids, IL-7, soluble receptor activator of nuclear factor κB ligand (sRANKL) and osteoprotegerin (OPG) in bone marrow transplantation (BMT) recipients. This study also examined whether the changes of these cytokine levels and sex steroids actually influence bone turnover and post-BMT bone loss by correlation analysis. Data were analyzed from 39 patients (33.6 ± 6.4 years, 19 men and 20 women) who had DXA performed before BMT and at 1 year after BMT. The bone turnover markers, sex steroids and the cytokine levels were measured before BMT and serially after BMT.

The mean bone loss in the lumbar spine and the total proximal femur was 5.9% (P < 0.01) and 11.3% (P < 0.01), respectively. During the immediate post-BMT period, bone formation decreased, whereas the bone resorption increased. For the female recipients, the estradiol levels declined at 1 week after BMT, and they did not recover to the basal levels. For the male recipients, the testosterone levels decreased at 1 week and then it increased to its baseline level. The IL-7 levels reached their maximum at 1 week and then declined to baseline level by 3 months. The serum sRANKL, OPG levels and the sRANKL/OPG ratio showed their peak at post-BMT 3 weeks.

The mean daily dose of steroid was associated with suppressed bone formation, enhanced bone resorption and increased sRANKL levels. The IL-7 levels were also noted to be either positively correlated with the levels of ICTP or they were negatively correlated with the levels of osteocalcin at 1 and 3 weeks after BMT. Bone loss at the lumbar spine and the proximal femur was influenced by the decreased sex steroids and increased IL-7 levels. During the observation period, the IL-7 levels showed positive correlations with the sRANKL levels and the sRANKL/OPG ratio. For the female patients, the serum IL-7 levels were negatively associated with the estradiol levels at 1 and 3 weeks after BMT.

All these findings suggest that IL-7 plays an important role for post-BMT bone loss, and this possibly happens via the RANKL pathway. These data also suggest that the up-regulation of IL-7 during the early post-BMT period may result from a deficiency of estrogen.     

Serum osteoprotegerin and its relationship with bone mineral density and markers of bone turnover

Introduction: The purpose of this study was to compare age-related differences in osteoprotegerin (OPG) in relationship with BMD and the serum bone markers osteocalcin (OC), collagen crosslinks (CTX), and tartrate-resistant acid phosphatase 5b (TRACP-5b). Methods: Data were derived from a cross-sectional study on bone health in a random sample of community-dwelling adults aged 30 to 85 years in the Reykjavik area in Iceland. All subjects had whole body, hip, and lumbar spine BMD measured (by DXA), gave blood samples, and answered a thorough questionnaire on medications and medical history. We assessed relationships using the Spearman correlation coefficient, partial correlation, and multivariable linear regression. Men and women were analyzed separately. Results: Of 2,310 subjects invited over 2 years, 1,630 participated. After excluding individuals with diseases and medications affecting bone metabolism, 517 women (age 56.1 ± 16.9 years) and 491 men (age 58.7 ± 14.9 years) remained for analysis. OPG increased steadily with age in both genders without a gender difference. In women, BMD at all sites declined steadily after age 50. In men, BMD remained relatively stable until age 70, after which it declined significantly. After controlling for age, BMI, and other confounding variables, OPG showed only a borderline positive relationship with whole body BMD in men (P=0.10), but the relationship was nonsignificant in women. In multivariable models, OPG was inversely related to TRACP-5b (P=0.002) and positively with OC (P=0.007), the OC/TRACP-5b (P=0.001) and OC/CTX (P=0.02) ratios in women. Among men, multivariable models showed a positive association between OPG and OC (P=0.05) and OC/TRACP-5b (P<0.009). Conclusions: We conclude that serum OPG levels are associated with a profile of bone turnover markers favoring bone formation, suggesting that OPG may be protective against age-related bone loss. Longitudinal studies are needed to address that issue.     

甲状旁腺激素在体外对破骨细胞分化及骨重吸收能力的影响

目的 探讨甲状旁腺激素(PTH)在体外直接对破骨细胞(OCs)分化及骨吸收能力的影响，以及其与成骨细胞(OBs)中核因子kB受体激活剂受体配体(ligand of receptor activator of nuclear factor kappa B，RANKL)基因和OPG(osteoprotegerin)基因表达的关系。方法体外直接用PTH诱导C3h小鼠全骨髓分化出OCs，用牙片小坑法(pits assayr)观察OCs对骨的重吸收能力。并采用多重RT-PCR方法检测在不同PTH作用浓度和不同作用时间的条件下,OBs中RANKL基因和OPG基因的表达情况。结果(1)PTH在体外可诱导C3h小鼠全骨髓分化出OCs，且在一定浓度范围内，随着PTH增加，OCs的形成数目和骨组织的破坏程度随之增加；(2)在一定PTH浓度和时间范围内，OBs中的RANKL-mRNA及OPG-mRNA表达呈剂量依赖性和时间依赖性。结论 PTH在体外可通过诱导RANKL基因和OPG基因表达而直接影响OCs的分化和骨重吸收功能。     

Rheumatoid arthritis: new insights into the role of synovial inflammation in joint destruction

 Rheumatoid arthritis (RA) is characterized by inflammation and proliferation of synovial tissue, leading to degradation of articular cartilage and bone with functional impairment as a result. It has recently become clear that early suppression of synovial inflammation is essential in preventing progressive joint destruction, although inflammation and destruction are in part uncoupled. New insights into the role of matrix metalloproteinases (MMPs), aggrecanase, granzyme B, receptor activator of nuclear factor κB (RANK)–receptor activator of nuclear factor κB ligand (RANKL) interaction, and other factors involved in joint destruction may lead to the development of novel therapies aimed at specific inhibition of cartilage and bone degradation. Correspondence to:P.P. Tak     

Sleep-disordered breathing is associated with depletion of circulating endothelial progenitor cells and elevation in pulmonary arterial pressure in patients with decompensated systolic heart failure

Background Sleep-disordered breathing (SDB) is known to occur frequently in and may predict worsening progression of patients with congestive heart failure (CHF). SDB is also known to play an important role in the development of idiopathic pulmonary arterial hyperten?sion (PAH) via inducing endothelial dysfunction and vascular remodeling, a pathological process that can be significantly influenced by factors such as osteoprotegerin (OPG) and endothelial progenitor cells (EPCs). The objective of this study is to determine if CHF with SDB is associated with changes in OPG, EPCs, and PAH. Methods EPCs were isolated, cultured, and quantified from CHF patients with SDB (n = 52), or without SDB (n = 68). OPG and N-terminal pro-brain natriuretic peptide (NT-proBNP) from each group was analyzed and correlated with EPCs and the mean pulmonary artery pressure (mPAP) measured by right heart catheterization. Results A significant decrease in circulating EPCs (29.30 ± 9.01 vs. 45.17 ± 10.51 EPCs/× 200 field; P < 0.05) was found in CHF patients with SDB compared to those without SDB. Both OPG (789.83 ± 89.38 vs. 551.29 ± 42.12 pg/mL; P < 0.05) and NT-proBNP (5946.50 ± 1434.50 vs. 3028.60 ± 811.90 ng/mL; P < 0.05) were also significantly elevated in SDB CHF patients who also had significantly elevated mPAP (50.2 ± 9.5 vs. 36.4 ± 4.1 mm Hg; P < 0.05). EPC numbers correlated inversely with the episodes of apnea and hypopnea per hour (RDI, r = –0.45, P = 0.037) and blood level of OPG (r = –0.53, P = 0.011). Although NT-proBNP was also increased significantly in patients with SDB, it had no correlation with either EPCs or RDI. Conclusions SDB due to hypoxemia from decompensated CHF is associated with (1) OPG elevation, (2) EPC depletion, and (3) mPAP elevation. The inverse relationship of circulating OPG with EPCs suggests a likely mechanism for hypoxemia and OPG in the development of pulmonary vascular dysfunction via depleting EPCs, thus worsening prognosis of CHF.     

失神经支配在大鼠骨折愈合过程中降钙素基因相关肽对骨保护素/破骨细胞分化因子影响的实验研究

目的 通过建立选择性切断大鼠感觉/运动神经联合胫骨骨折的动物模型,研究感觉/运动神经损伤后对骨折愈合的影响,并检测骨折愈合过程中降钙素基因相关肽(calcitonin gene related peptide,CGRP)对骨保护素(osteoprotegerin,OPG)/破骨细胞分化因子(receptor activator nuclear factor kappa B ligand,RANKL)体系的影响,初步探讨周围神经调节骨折愈合的机制.方法 取60只Wistar大鼠随机分为3组:前根(运动神经)切断+胫骨骨折组(anterior rhizotomy group,ART组);后根(感觉神经)切断+胫骨骨折组(posterior rhizotomy group,PRT组);单纯胫骨骨折组(sham operated group,SO组).分别于骨折术后7、14、21、28d处死大鼠,在骨折处上、下5mm部位取骨痂标本.免疫组织化学检测CGRP、OPG、RANKL的表达;采用软件Image-proplus 6.0进行图片分析;采用SPSS16.0进行统计学分析.结果 CGRP在SO组各时间点均呈强阳性表达,术后14 d和21 d,SO组、ART组和PRT组比较差异均有统计学意义(P＜0.05).OPG在SO组术后7d呈强阳性表达,以后逐渐下降但保持较高水平;术后14 d,PRT组和SO组、ART组比较差异有统计学意义(P＜0.05);术后21 d,SO组和PRT组、ART组比较差异有统计学意义(P＜0.05).RANKL在SO组21 d为表达高峰,以后逐渐下降;术后14 d,PRT组和ART组、SO组比较差异有统计学意义(P＜0.05);术后21 d,SO组和ART组、PRT组比较差异有统计学意义(P＜0.05).结论 在骨折愈合过程中,感觉神经纤维对骨折愈合的影响较运动神经纤维显著.CGRP能够调节OPG/RANKL的表达量的比值,从而影响骨折的愈合过程.失神经支配(尤其是感觉神经)导致CGRP对OPG/RANKL表达的调节作用降低,这不利于骨折的愈合.完整的神经支配是正常骨折愈合的必要条件之一.     

单侧髋关节置换术患者手术前后外周血中OPG与RANKL浓度对比分析

[目的]探讨老年患者（≥65岁）单侧髋关节术后短期内骨代谢变化.[方法]收集单侧髋关节置换手术患者术前后18例外周血液,采用ELISA法检测血清中骨保护素（OPG）、核激活因子受体配体（RANKL）手术前后浓度,分析OPG、RANKL表达水平变化.[结果]单侧18例行髋关节置换术患者术后OPG浓度均较术前明显增加,而16例患者术后RANKL浓度均明显下降,其中2例患者术后RANKL浓度轻度增加,术后患者RANKL/OPG比值总体下降.[结论]老年患者单侧髋关节术后OPG浓度增加和RANKL浓度的下降,导致RANKL/OPG比值总体下降,提示此类患者其术后短期内破骨功能可能受抑制而成骨功能却明显增强.