下调骨细胞TGF-β/Smad4信号可抑制小鼠BMSCs成骨及破骨分化

目的检测骨细胞TGF-β/Smad4信号通路对骨髓间充质干细胞(BMSCs)成骨和破骨分化的作用,并初步探讨其相关机制。方法用条件性基因敲减Cre/loxp技术特异性敲减骨细胞Smad4,获得下调骨细胞TGF-β/Smad4信号通路的小鼠;体外分离骨细胞并与野生型小鼠骨髓间充质细胞(BMSCs)共培养;碱性磷酸酶(ALP)染色、茜素红(alizarin red)染色检测早期成骨分化和晚期钙盐沉积,酸性磷酸酶(TRAP)染色检测破骨细胞;real-time PCR检测成骨分化特异标志物Runx2、Osterix(OSX)、ALP、osteocalcin和破骨分化特异标志物RANKL和OPG的mRNA表达水平。Western blot检测成骨分化特异标志物Runx2和osteocalcin和破骨分化特异标志物RANK蛋白表达水平。结果下调骨细胞TGF-β/Smad4信号能够抑制BMSCs成骨转录因子Runx2、Osterix(P0.01)、成骨分化特异标志物ALP和osteocalcin(P0.01)以及破骨分化特异标志物RANK(P0.01)的表达;增加破骨分化抑制物OPG的表达(P0.05);而RANKL的表达无明显变化;最终下调了RANKL/OPG的比值(P0.05)。结论终末分化的骨细胞调控骨的代谢,下调其TGF-β/Smad4信号可抑制BMSCs成骨和破骨细胞的分化。     

聚甲基丙烯酸甲酯颗粒对人滑膜细胞核因子κB受体激动剂配体/骨保护蛋白表达的影响

背景：多种因子可以影响骨保护蛋白/核因子κB受体激动剂配体/核因子κB受体激动剂(Osteoprotegerin / receptor activator of nuclear factor-kappaB/ligand of receptor-activator of nuclear factor-kappaB,OPG/RANKL/RANK)系统的表达影响骨代谢,那么松动假体周围的骨水泥颗粒是否也通过影响其代谢参与假体松动过程？ 目的：观察聚甲基丙烯酸甲酯颗粒对人滑膜细胞RANKL/OPG表达的影响。 方法：体外培养人滑膜细胞,在滑膜细胞培养体系中分别加入质量浓度为0(空白对照),0.2,1,10 g/L的聚甲基丙烯酸甲酯骨水泥颗粒,采用荧光定量PCR检测上述各浓度PMMA颗粒作用不同时间后滑膜细胞内RANKL、OPG的表达量及其比值。 结果与结论：与空白对照组相比,各实验组滑膜细胞内RANKL、OPG的表达量均有下降;随着与聚甲基丙烯酸甲酯颗粒共培养时间延长,各实验组滑膜细胞内RANKL、OPG表达均有下降趋势,而RANKL/OPG表达比值无明显变化。说明聚甲基丙烯酸甲酯颗粒在对滑膜细胞产生生物学反应时并不干扰假体周围骨代谢的动态平衡,并未直接参与人工关节假体的无菌性松动。     

骨保护蛋白对类风湿疾病相关骨吸收的作用

骨保护蛋白(osteoprotegerin,OPG)是由成骨细胞(osteoblast)表达、分泌的TNF受体家族一成员,它对调节骨代谢有作用。作为诱饵受体,OPG能与其配体RANKL以高亲和力结合,阻止RANKL与受体RANK的结合,从而抑制破骨细胞参与的骨吸收。OPG对免疫系统也有重要的调节作用。RANKL缺陷小鼠表现出严重的免疫学异常和骨硬化(osteopetrosis)。活化的T细胞能表达RANKL mR-NA,其分泌RANKL的量受许多细胞因子的调节:一些促进炎症和骨吸收的细胞因子(诸如TNF-α、IL-1和IL-17)可以提高其产生,进而诱导破骨细胞生成(osteoclastogenesis);相反,这一过程可以被OPG、IL-4和IL-10(他们具有抗炎症效应和抑制破骨细胞形成作用)抑制。类风湿性关节炎滑膜中的活化T细胞也表达RANKL;在特定条件下(尤其当他们与M-GSF和RANKL共培养时),滑膜细胞(synoviocyte)可以分化成破骨细胞样细胞。因此,类风湿性关节炎中可以见到的骨侵蚀(bone erosion)可能是RANKL/RANK系统被活化T细胞活化的结果。这为用OPG来阻断这一机制以改善RA病人的症状提供了理论依据。     

骨保护蛋白对类风湿疾病相关骨吸收的作用

骨保护蛋白（osteoprotegerin,OPG）是由成骨细胞（osteoblast）表达、分泌的TNF受体家族一成员,它对调节骨代谢有作用.作为诱饵受体,OPG能与其配体RANKL以高亲和力结合,阻止RANKL与受体RANK的结合,从而抑制破骨细胞参与的骨吸收.OPG对免疫系统也有重要的调节作用.RANKL缺陷小鼠表现出严重的免疫学异常和骨硬化（osteopetrosis）.活化的T细胞能表达RANKL mRNA,其分泌RANKL的量受许多细胞因子的调节：一些促进炎症和骨吸收的细胞因子（诸如TNF-α、IL-1和IL-17）可以提高其产生,进而诱导破骨细胞生成（osteoclastogenesis）;相反,这一过程可以被OPG、IL-4和IL-10（他们具有抗炎症效应和抑制破骨细胞形成作用）抑制.类风湿性关节炎滑膜中的活化T细胞也表达RANKL;在特定条件下（尤其当他们与M-GSF和RANKL共培养时）,滑膜细胞（synoviocyte）可以分化成破骨细胞样细胞.因此,类风湿性关节炎中可以见到的骨侵蚀（bone erosion）可能是RANKL/RANK系统被活化T细胞活化的结果.这为用OPG来阻断这一机制以改善RA病人的症状提供了理论依据.     

OPG/RANKL/RANK信号通路在骨巨细胞瘤发病机制中的作用

文题释义：OPG/RANKL/RANK 信号通路：是骨代谢中至关重要的一条信号通路,它是成骨细胞与破骨细胞之间相互作用的信号通道,同时也是骨巨细胞瘤影响骨代谢的主要途径。 骨巨细胞瘤(Giant cell tumor of bone,GCTB)：是常见的原发性骨肿瘤之一,其发病率占所有原发性骨肿瘤的4%-10%,多发生于20-40岁的青壮年患者,好发于股骨远端、胫骨近端或桡骨远端。骨巨细胞瘤组织学来源尚不清楚,一般认为起始于骨髓内间叶组织。该肿瘤具有较强的侵袭性,对骨质有较大的破坏和侵蚀作用,但很少有患者出现反应性新骨生成或是自愈倾向。 背景：研究表明,骨保护素/核因子κB受体活化因子配体/核因子κB受体活化因子(OPG/RANKL/RANK)信号通路与骨巨细胞瘤发病机制之间有一定的相关性,通过控制OPG/RANKL/RANK信号通路影响成骨细胞与破骨细胞之间相互作用,对该病起到一定的治疗作用。 目的：介绍 OPG/RANKL/RANK信号通路与骨巨细胞瘤发病机制的关系,总结并讨论OPG/RANKL/RANK信号通路在骨巨细胞瘤发病机制中的最新研究进展。 方法：检索 PubMed 数据库、Web of science数据库及万方数据库中2001至2019年相关文献,检索词分别为“OPG/RANKL/RANK,giant cell tumor of bone,pathogenesis,signal pathway, bone metabolism,OPG/RANK/RANKL,骨巨细胞瘤,发病机制,信号通路,骨代谢”。排除较陈旧及重复的文献,通过整理,共纳入53篇文献进行分析探讨。 结果与结论：①骨保护素抑制破骨细胞增殖及分化,降低成熟破骨细胞活性,阻断核因子κB受体活化因子配体与核因子κB受体活化因子结合,减缓破骨;②核因子κB受体活化因子配体与破骨细胞前体细胞表面的核因子κB受体活化因子结合,促进破骨细胞前体细胞分化,增殖,进而加速破骨;③核因子κB受体活化因子配体与其受体结合后,激活核因子κB等信号因子促进破骨细胞的增殖、分化并激活破骨细胞,同时调节相关基因的转录及表达;④OPG/RANK/RANKL与骨巨细胞瘤发病机制相关。 ORCID: 0000-0002-2756-4848(梁晨亮) 中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程     

骨巨细胞瘤中骨保护因子及破骨细胞分化因子的表达

目的 检测骨巨细胞瘤中骨保护因子（OPG）及破骨细胞分化因子（ODF）mRNA的表达,并探讨多核巨细胞的来源及造成骨吸收的分子机制。方法 采用半定量逆转录－聚合酶链反应（RT－PCR）方法检测骨巨细胞瘤和正常骨组织中OPG、ODF及其辅助因子巨噬细胞克隆刺激因子、信号受体RANK mRNA的表达,并将两种组织中各因子的表达情况进行半定量比较。结果 正常骨组织中OPG、巨噬细胞克隆刺激因子、RANK mRNA有表达,ODF呈微弱表达;骨巨细胞瘤中OPG、ODF、巨噬细胞克隆刺激因子、RANK mRAN均有表达,ODF的表达非常丰富。骨巨细胞瘤中ODF与OPG的比值远远高于正常骨组织。结论 骨巨细胞瘤中的微环境具备破骨细胞形成及其促进骨吸收的必要条件,多核巨细胞的来源及其骨吸收功能与上述几种因子的表达有关。     

建立小鼠成骨与破骨细胞相互作用的共育新体系

背景：众所周知,骨重建是骨组织中重要的生物学反应过程,其中成骨细胞与破骨细胞发挥了关键作用。但目前,关于骨重建中成骨与破骨细胞间信号传递的深层机制还不清楚。 目的：利用transwell技术,在体外建立一种成骨与破骨细胞的新型共育体系,为深入研究骨重建中成骨与破骨细胞的相互作用提供成熟的实验模型。 方法：采用MC3T3-E1成骨样细胞株与RAW264.7破骨前体细胞株,进行体外成骨与破骨细胞的诱导分化,并利用Transwell共培养板(0.4 µm聚酯膜)建立成骨与破骨细胞的共育体系。共培养6 d后,通过测定细胞活性和碱性磷酸酶(ALP)活力分析成骨细胞的增殖和分化活性,利用抗酒石酸酸性磷酸酶(TRAP)染色、甲苯胺蓝(TB)染色、TRAP活性测定及扫描电镜技术观察破骨细胞的分化及骨吸收功能。 结果与结论：共培养体系中成骨样细胞的无限增殖能力减弱,而分化活性明显增强,同时破骨前体细胞被诱导分化为成熟的破骨细胞,并具有一定的骨吸收功能。因此,该共培养体系可用于骨重建中成骨与破骨细胞间信号通路的深层研究。     

成骨／基质细胞在破骨细胞分化中的作用

骨组织微环境中，成骨／基质细胞表达的骨保护素(osteoprotegerin，OPG)和骨保护素配体(osteoprotegerin ligand，OPGL)是调节骨代谢的重要因子。研究表明，成骨／基质细胞的OPG／OPGL相对表达水平与破骨细胞的分化、成熟及骨吸收直接相关。各种刺激骨吸收的生物、物理因素均通过调节成骨／基质细胞的OPG／OPGL相对表达活性，影响破骨细胞的分化和成熟。     

成骨/基质细胞在破骨细胞分化中的作用

骨组织微环境中,成骨/基质细胞表达的骨保护素(osteoprotegerin,OPG)和骨保护素配体(osteoprotegerin ligand,OPGL)是调节骨代谢的重要因子。研究表明,成骨/基质细胞的OPG/OPGL相对表达水平与破骨细胞的分化、成熟及骨吸收直接相关。各种刺激骨吸收的生物、物理因素均通过调节成骨/基质细胞的OPG/OPGL相对表达活性,影响破骨细胞的分化和成熟。     

骨水泥中的硫酸钡对破骨细胞的作用

目的验证骨水泥中的硫酸钡对破骨细胞形成及其生物学活性的影响。方法体外培养外周血单核细胞并加入巨噬细胞克隆集落刺激因子及核因子B激活因子配体诱导破骨细胞分化,实验组中分别加入含有或不含有硫酸钡的骨水泥颗粒。以抗酒石酸酸性磷酸酶阳性多核细胞及象牙磨片上虫蚀样骨吸收陷窝的形成昨作为检测破骨细胞形成及其骨吸收活性的检测指标,检验骨水泥中的硫酸钡对破骨细胞的影响。结果含或不含硫酸钡的骨水泥颗粒组抗酒石酸酸性磷酸酶阳性多核细胞形成均早于无骨水泥颗粒的对照组（4天vs6天）,而骨水泥颗粒中是否含有硫酸钡的两组间抗酒石酸酸性磷酸酶阳性多核细胞形成的时间无明显差异。各组间抗酒石酸酸性磷酸酶阳性多核细胞的数量无显著差异;含硫酸钡的骨水泥颗粒组象牙磨片上骨吸收陷窝的面积较不含硫酸钡的骨水泥颗粒组及阴性对照组均增大（28.26±4.98vs22.28±3.49vs14.58±2.82,〈0.05）。结论骨水泥颗粒中的硫酸钡能够促进破骨细胞分化并促进成熟破骨细胞的骨吸收活性。     

Lymphocytes and synovial fluid fibroblasts support osteoclastogenesis through RANKL, TNFalpha, and IL-7 in an in vitro model derived from human psoriatic arthritis

Psoriatic arthritis (PsA) is an inflammatory joint disease, characterized by extensive bone resorption, whose mechanisms have not been fully elucidated. Thus, in the present study we investigated the involvement of RANKL, TNFalpha, and IL-7 in the osteoclastogenesis of PsA patients. In vitro osteoclastogenesis models, consisting of unfractionated and T-cell-depleted mononuclear cells from peripheral blood (PBMCs) and synovial fluid (SFMCs) of 20 PsA patients as well as from healthy donors were studied. Freshly isolated T and B cells from PBMCs and T cells and fibroblasts from SFMCs of PsA patients were subjected to RT-PCR to detect the levels of RANKL, TNFalpha, and IL-7. Osteoclastogenesis was studied in the presence of RANK-Fc, anti-TNFalpha, and anti IL-7 functional antibodies. We demonstrate that lymphocytes and fibroblasts support osteoclast (OC) formation in PsA patients through the production of osteoclastogenic cytokines. In particular, OC formation was completely abolished in unstimulated T cell-depleted PBMC cultures, and reduced by approximately 70% in unstimulated T cell-depleted SFMC cultures. Freshly isolated T cells from PBMCs and SFMCs of PsA patients overexpressed RANKL and TNFalpha, while fibroblasts from synovial fluid produced only RANKL. We show that the presence of RANK-Fc and/or anti-TNFalpha functional antibodies reduced OC formation. Moreover, T and B cells from PBMCs as well as T cells and fibroblasts from SFMCs expressed IL-7 mRNA. Finally, the anti-IL-7 functional antibody significantly reduced osteoclastogenesis. Our results suggest that fibroblasts, B and T lymphocytes support OC formation by producing RANKL, TNFalpha, and IL-7, contributing to the aggressive bone resorption in PsA patients.     

Substance P enhanced titanium particles-induced RANKL expression in fibroblasts from periprosthetic membrane

Abstract

Aseptic loosening remains the primary cause of failure in total joint arthroplasty. Implant-derived particles are thought to be a main cause of osteolysis that leads to the failure. Substance P (SP) immunoreactive nerve fibers have been detected in the periprosthetic membrane of aseptic loose hip prostheses. We isolated fibroblasts from periprosthetic membrane. Fibroblasts were examined by real-time RT-PCR and enzyme-linked immunosorbent assay for expression of the receptor activator of nuclear factor kappa B ligand (RANKL), osteoprotegerin (OPG), cyclooxygenase (COX)-1, and COX-2. Experiments were performed in the presence and absence of titanium particles, SP and NS-398 (a selective COX-2 inhibitor). Titanium particles or SP stimulated RANKL and COX-2 expression in fibroblasts, whereas NS-398 inhibited RANKL production, suggesting a COX-2-mediated event. Moreover, SP enhanced COX-2 and RANKL expression by titanium particles-stimulated fibroblasts. Thus, SP and titanium particles acted synergistically to increase RANKL expression.     

LPS-stimulated human gingival fibroblasts inhibit the differentiation of monocytes into osteoclasts through the production of osteoprotegerin

Periodontitis is an inflammatory bone disease caused by Gram-negative anaerobic bacteria, but the precise mechanism of bone destruction remains unknown. Activated T lymphocytes secrete receptor activator of NF-kappaB ligand (RANKL) and support the differentiation of monocytes into mature osteoclasts. The purpose of this study was to examine the expression of RANKL and its inhibitor, osteoprotegerin (OPG), in inflamed gingival tissue and to clarify the role of human gingival fibroblasts (HGFs) in osteoclastogenesis regulated by RANKL. HGFs and gingival mononuclear cells (GMCs) were obtained from chronic periodontitis patients during routine periodontal surgery. Expression of OPG and RANKL mRNA in gingival tissue and HGFs was examined with RT-PCR. OPG production was measured using ELISA. Expression of RANKL, CD4, CD8 and CD69 on GMCs was determined by flow-cytometry using RANK-Fc fusion protein and the respective monoclonal antibodies. Osteoclastogenesis by RANKL was assayed by counting the number of tartarate-resistant acid phosphatase (TRAP)-positive cells after culturing human peripheral blood monocytes with recombinant human RANKL and macrophage-colony stimulating factor (M-CSF) for 10 days. OPG and RANKL mRNA were expressed in 80% (16/20) and 25% (5/20) of periodontitis lesions, respectively. OPG, but not RANKL, mRNA was expressed within HGFs. OPG mRNA expression and production by HGFs was augmented by LPS stimulation. All GMC samples expressed CD69, and two of five GMC samples expressed RANKL. The culture supernatant of LPS-stimulated gingival fibroblasts significantly reduced the number of TRAP positive cells generated by culturing monocytes with RANKL and M-CSF. The present study suggests that LPS-stimulated HGFs inhibit monocyte differentiation into osteoclasts through the production of OPG.     

IL-15 promotes osteoclastogenesis via the PLD pathway in rheumatoid arthritis

Osteoclastogenesis plays an important role in joint destruction in rheumatoid arthritis (RA). IL-15 is a pleiotropic proinflammatory cytokine that appears to help mediate the pathological bone loss. This study was undertaken to explore the signaling molecules essential for osteoclastogenesis mediated by IL-15 in rheumatoid synovial fibroblasts. Expression of phospholipase D1 (PLD1) and osteoclast-related gene expression in synovial tissues and their modulation by treatment with IL-15 and different inhibitors in synovial fibroblasts of RA patients were evaluated using immunohistochemistry and quantitative polymerase chain reaction. The levels of IL-15 in serum and synovial fluid were measured by ELISA. The effects of IL-15 and phosphatidic acid (PA) on osteoclast formation were evaluated in cocultures of rheumatoid synovial fibroblasts and peripheral blood monocytes or monocytes alone in the presence of M-CSF and RANKL. The levels of RANKL and PLD1 but not PLD2 were upregulated significantly by IL-15, and the RANKL level was significantly upregulated by PA in rheumatoid synovial fibroblasts. Blocking PA production with 1-butanol and siRNA against PLD1 significantly inhibited the IL-15-stimulated expression of RANKL and PLD1. IL-15 levels were significantly higher in serum and synovial fluid from patients with RA than in osteoarthritis patients and healthy controls. IL-15 and PA induced osteoclast formation through the mitogen-activated protein kinases (MAPKs) and NF-κB signaling pathways. Activation of PLD1 contributes to IL-15-mediated osteoclastogenesis via the MAPKs and NF-κB signaling pathways in rheumatoid synovial fibroblasts. Our data suggest that PLD1 might be an efficient therapeutic strategy for preventing bone destruction in rheumatoid arthritis.     

The cytolethal distending toxin induces receptor activator of NF-kappaB ligand expression in human gingival fibroblasts and periodontal ligament cells

Actinobacillus actinomycetemcomitans is associated with localized aggressive periodontitis, a disease characterized by rapid loss of the alveolar bone surrounding the teeth. Receptor activator of NF-kappaB Ligand (RANKL) and osteoprotegerin (OPG) are two molecules that regulate osteoclast formation and bone resorption. RANKL induces osteoclast differentiation and activation, whereas OPG blocks this process by acting as a decoy receptor for RANKL. The purpose of this study was to investigate the effect of A. actinomycetemcomitans on the expression of RANKL and OPG in human gingival fibroblasts and periodontal ligament cells. RANKL mRNA expression was induced in both cell types challenged by A. actinomycetemcomitans extract, whereas OPG mRNA expression remained unaffected. Cell surface RANKL protein was also induced by A. actinomycetemcomitans, whereas there was no change in OPG protein secretion. A cytolethal distending toxin (Cdt) gene-knockout strain of A. actinomycetemcomitans did not induce RANKL expression, in contrast to its wild-type strain. Purified Cdt from Haemophilus ducreyi alone, or in combination with extract from the A. actinomycetemcomitans cdt mutant strain, induced RANKL expression. Pretreatment of A. actinomycetemcomitans wild-type extract with Cdt antiserum abolished RANKL expression. In conclusion, A. actinomycetemcomitans induces RANKL expression in periodontal connective tissue cells. Cdt is crucial for this induction and may therefore be involved in the pathological bone resorption during the process of localized aggressive periodontitis.     

Substance P augments PGE2 and IL-6 production in titanium particles-stimulated fibroblasts from hip periprosthetic membrane

Aseptic loosening remains the primary cause of failure in total joint arthroplasty. Implant-derived particles are thought to be a main cause of osteolysis that leads to failure of total joint arthroplasty. The nervous system has been implicated in the etiology and pathogenesis of joint diseases. Substance P (SP) immunoreactive nerve fibers have been detected in the pseudomembrane and pseudocapsular tissues of aseptic loose hip prostheses, suggesting that SP might be involved in the process of aseptic loosening. Fibroblasts are abundant in periprosthetic membrane. Neuropeptides are able to modulate cytokine production by fibroblasts. In this study, we isolated fibroblasts from periprosthetic membrane at the time of revision hip arthroplasty performed because of aseptic loosening. Fibroblasts were stimulated with titanium (Ti) particles or SP. Prostaglandin (PG) E2 and interleukin-6 (IL-6) assays were performed using enzyme-linked immunosorbent assay kit. PGE2 and IL-6 secretion by fibroblasts have been significantly increased in the presence of Ti particles or SP. Moreover SP caused significant increase in PGE2 and IL-6 production by Ti particles-stimulated fibroblasts. Thus, SP and Ti particles acted synergistically to increase PGE2 and IL-6 secretion in fibroblasts from periprosthetic membrane.     

Osteoprotegerin/RANK/RANKL axis in cardiac remodeling due to immuno-inflammatory myocardial disease

Objective

Osteoprotegerin (OPG) and the receptor activator of nuclear factor-κB ligand (RANKL) are inflammatory cytokines traditionally linked to the regulation of bone remodeling. We hypothesize that the OPG/RANK/RANKL axis may be involved in extracellular matrix remodeling in immuno-inflammatory heart diseases, and explore the probable underlying mechanisms by using anti-IL-17 in the model of experimental autoimmune myocarditis.

Methods

EAM was induced in Lewis rats by injection of porcine cardiac myosin. All the rats were randomly distributed into day 0, day 7, day 14 and day 28 groups, which means rats in certain group were cervical dislocated on day 0, day 7, day 14 and day 28 respectively. HE staining and Masson's staining were used for measurement of cardiac hypertrophy and interstitial fibrosis. Hydroxyproline content and collagen cross-linking were determined in heart section. Anti-IL-17 or control antibody was injected i.p. 2 h before and 3 days and 7 days after the first myosin immunization in EAM model, that is, group anti-IL-17 or group control antibody. IL-17 and OPG/RANK/RANKL axis expressions were detected by realtime RT-PCR in all the six groups. In the in vitro studies, cardiac fibroblasts were cultured and treated with IL-17 or vehicle for 48 h. Total RNA was isolated from harvested cells and realtime RT-PCR was performed to detect the RANK, RANKL, OPG and MMP-2, MMP-9, TIMP-1 and TIMP-2 expressions, then matrix metalloproteinase activity was assayed.

Results

Our in vivo results revealed that expression of IL-17 and the OPG/RANK/RANKL axis increased significantly from day 0 to day 28, with IL-17 and OPG increased relatively steeply. In the in vitro study, we detected OPG, RANK and RANKL mRNA expressions in the cultured fibroblasts with or without IL-17 stimulation. We found that IL-17 increased the OPG/RANK/RANKL axis activity (P < 0.05). Although IL-17 induced a significant increase in MMP-2 and MMP-9 gene expressions in cardiac fibroblasts, there was no change in TIMP-2 and TIMP-1 expressions.

Conclusions

Our results suggest that the OPG/RANK/RANKL axis may be involved in cardiac remodeling in immuno-inflammatory myocardial diseases and progression of chronic HF and thus may represent targets for intervention in this disorder.     

Obstructive Fibrinous Tracheal Pseudomembrane After Tracheal Intubation: A Case Report

Obstructive fibrinous tracheal pseudomembrane is a rare, but potentially fatal complication associated with endotracheal intubation. It has been known that the formation of tracheal pseudomembrane is related with intracuff pressure during endotracheal intubation or infectious cause. But in the patient described in this case, pseudomembrane formation in the trachea was associated with subglottic epithelial trauma or caustic injuries to the trachea caused by aspirated gastric contents during intubation rather than tracheal ischemia due to high cuff pressure. We report a patient with obstructive fibrinous tracheal pseudomembrane after endotracheal intubation who presented with dyspnea and stridor and was treated successfully with mechanical removal using rigid bronchoscopy.     

Regulation of RANKL and OPG gene expression in human gingival fibroblasts and periodontal ligament cells by Porphyromonas gingivalis: a putative role of the Arg-gingipains

Porphyromonas gingivalis is highly implicated in the pathogenesis of periodontitis, which is characterized by the destruction of periodontal connective tissues and the supporting alveolar bone. Receptor Activator of NF-kappaB Ligand (RANKL) stimulates bone resorption, whereas osteoprotegerin (OPG) blocks its action, and this bi-molecular system is implicated in periodontitis. The aim of this work was (a) to investigate the regulation of RANKL and OPG gene expression in human periodontal ligament (PDL) cells and gingival fibroblasts (GF), in response to P. gingivalis culture supernatants, by quantitative real-time PCR and (b) to attempt to identify putative virulence factors involved in this process. The results indicated that P. gingivalis induced RANKL and reduced OPG mRNA expression by the studied cells, resulting in an increased RANKL/OPG expression ratio. Heat-inactivation of P. gingivalis resulted in significant reduction of RANKL mRNA expression. A Lys-gingipain mutant strain did not affect, whereas an Arg-gingipain mutant strain further enhanced RANKL mRNA expression, compared to their parental wild-type strain. In conclusion, P. gingivalis up-regulates the RANKL/OPG expression ratio in GF and PDL cells, denoting an enhanced osteoclastogenic potential by the cells. The component mainly responsible for RANKL induction appears to be proteinaceous, and it may be regulated by the Arg-gingipains.