Cross‐reactive adaptive immune response to oral commensal bacteria results in an induction of receptor activator of nuclear factor‐κB ligand (RANKL)‐dependent periodontal bone resorption in a mouse model

Introduction: The present study examined whether induction of an adaptive immune response to orally colonizing non‐pathogenic Pasteurella pneumotropica by immunization with the phylogenetically closely related bacterium, Actinobacillus actinomycetemcomitans, can result in periodontal bone loss in mice. Methods: BALB/c mice harboring P. pneumotropica (P. pneumotropica⁺ mice) in the oral cavity or control P. pneumotropica‐free mice were immunized with fixed A. actinomycetemcomitans. The animals were sacrificed on day 30, and the following measurements were carried out: (i) serum immunoglobulin G and gingival T‐cell responses to A. actinomycetemcomitans and P. pneumotropica; (ii) periodontal bone loss; and (iii) identification of receptor activator of nuclear factor‐κB ligand (RANKL) ‐positive T cells in gingival tissue. Results: Immunization with A. actinomycetemcomitans induced a significantly elevated serum immunoglobulin G response to the 29‐kDa A. actinomycetemcomitans outer membrane protein (Omp29), which showed strong cross‐reactivity with P. pneumotropica OmpA compared to results in the control non‐immunized mice. The A. actinomycetemcomitans‐immunized P. pneumotropica⁺ mice developed remarkable periodontal bone loss in a RANKL‐dependent manner, as determined by the abrogation of bone loss by treatment with osteoprotegerin‐Fc. The T cells isolated from the gingival tissue of A. actinomycetemcomitans‐immunized P. pneumotropica⁺ mice showed an in vitro proliferative response to both A. actinomycetemcomitans and P. pneumotropica antigen presentation, as well as production of soluble(s)RANKL in the culture supernatant. Double‐color confocal microscopy demonstrated that the frequency of RANKL⁺ T cells in the gingival tissue of A. actinomycetemcomitans‐immunized P. pneumotropica⁺ mice was remarkably elevated compared to control mice. Conclusion: The induction of an adaptive immune response to orally colonizing non‐pathogenic P. pneumotropica results in RANKL‐dependent periodontal bone loss in mice.     

阿霉素诱导鸟嘌呤-四联体形成对Tca8113细胞端粒酶及细胞周期的影响

目的：探讨阿霉素影响端粒酶活性、端粒酶mRNA表达、细胞周期及周期蛋白表达的分子作用机制。方法：采用端粒重复序列扩增法（TRAP）、改良TRAP—G4法和RT—PCR法检测Tca8113细胞端粒酶活性变化、端粒酶hTERT和TP1mRNA水平；流式细胞仪分析细胞周期；采用Western印迹法测定CyclinB1和CyclinA表达水平。采用SPSS10．0软件包对数据进行t检验。结果：所有实验浓度阿霉素均可降低Tca8113细胞端粒酶活性．当端粒酶作用底物变为5＇-（GGGATr），GGGTT-3’时，端粒延伸反应完全受到抑制；5μg/ml阿霉素作用24h后，hTERT和TP1mRNA表达降低，CyclinB1表达明显增强，G2／M期细胞百分率显著下降。结论：阿霉素抑制端粒酶活性、降低端粒酶表达、影响细胞周期及CyclinB1表达的作用机制与其诱导鸟嘌呤-四联体形成有关。     

Salivary and serum antibody response to Streptococcus mutans antigens in humans

Humoral immunity against Streptococcus mutans infection was analyzed in caries-active and caries-free young adults by immunoblotting. All volunteers from both groups had detectable salivary immunoglobulin A (IgA) and serum IgG antibodies, with similar profiles. They could be classified on the basis of relative intensity of the immunoblot bands into categories of high or low responders. Common protein antigens with molecular weight ranging from approximately 45 to 190 kDa could be found either extracellularly or associated with the cell wall of S. mutans cultured in vitro. The predominant reactive antigens recognized by both IgA and IgG were of proteins around 63 and 60 kDa. Detection of IgA antibodies to the various antigens of S. mutans in individual saliva samples did not always correlate with serum IgG antibody profiles. In addition, distinct bands, which reacted preferentially with either IgA or IgG, could be detected by antibodies from specific subjects. Differential reactivities of salivary IgA and serum IgG antibodies to two, cell-wall associated protein antigens around 33 and 36 kDa were found in caries-active and caries-free young adults; 30.8% of caries-free subjects and 12% of caries-active subjects (P < 0.01) exhibited detectable antibody response to these antigens. This difference was not attributable to variations in antibody levels, since antibody response to these proteins were still detectable in some caries-free but not caries-active individuals whose levels of antibodies to other antigens were low. Thus, a new antibody profile which correlates with dental caries disease activity has been identified in a selected population. Differences in mucosal and systemic immune responses to S. mutans seem to be both antigen and host dependent.     

Role of interleukin-1 and inflammasomes in oral disease

BackgroundInflammation promotes immune cell infiltration into tissues and induces production of pro-inflammatory cytokines that mediate innate immune responses. Acute or temporary inflammation results in the required repair of the inflamed tissues. However, chronic inflammation leads to pathogenesis of inflammatory conditions such as periodontal disease. In periodontal tissues, pro-inflammatory cytokines mediate inflammatory responses and accelerate the bone-resorbing activity of osteoclasts, resulting in destruction of alveolar bone. Levels of interleukin-1 (IL-1), a major pro-inflammatory cytokine that strongly promotes osteoclastic activity, are elevated in oral tissues of patients with periodontitis. Therefore, elucidation of the mechanisms underlying IL-1 production will enhance our understanding of the pathogenesis of periodontal disease.HighlightIL-1 has two isoforms: IL-1α and IL-1β. Both isoforms bind to the same IL-1 receptor and have identical biological activity. Unlike that of IL-1α, the IL-1β precursor is not bioactive. To induce its bioactivity, the IL-1β precursor is cleaved by caspase-1, whose activation is mediated by multiprotein complexes termed inflammasomes. Thus, IL-1β maturation and activity are strictly regulated by inflammasomes. This review highlights the current understanding of the molecular mechanisms underlying IL-1 production and the related inflammasome activity.ConclusionInhibition of IL-1 production or the inflammasomes via their regulatory mechanisms may facilitate prevention or treatment of periodontal disease and other inflammatory diseases.     

Oxygen-dependent modulation of release and activity of polymorphonuclear leukocyte granule products

Polymorphonuclear leukocytes are important in the defense against the anaerobic microflora of infected gingival pockets. One part of this defense is release of antibacterial granule products by polymorphonuclear leukocytes into the pockets. The aim of the present study was to compare the efficiency of polymorphonuclear leukocytes in releasing granule products under aerobic and anaerobic conditions. Polymorphonuclear leukocytes were exposed to serum-opsonized zymosan under aerobic and anaerobic conditions. The levels of released granule products were determined by combining measurements of activity with enzyme-linked immunosorbent assays. The level of released elaslase was twice as high in anaerobic as in aerobic reaction mixtures. A similar difference was not detected for mycloperoxidase. However, mycloperoxidase was inactivated after its release under aerobic conditions. The release of lactoferrin was as efficient under aerobic as under anaerobic conditions. The effect of aerobic conditions on the release of elastase and the inactivation of myeloperoxidase could be ascribed to oxidants formed in the mycloperoxidase-H₂O₂-chloride system. Also, the activity of the released cytoplasmic enzyme lactate dehydrogenase was inactivated by oxidants formed in the myeloperoxidase-H₂O₂-chloride system. These findings suggest that, in the anaerobic environment of the gingival pocket, elastase and possibly also other azurophilic granule products are released in higher amounts than under fully oxygenated conditions. In this environment, the released products may also escape inaclivation by the myeloperoxidase- H₂O₂-chloride system.     

产前IgG血型抗体效价与新生儿ABO溶血病病例分析

目的 分析产前免疫球蛋白G(IgG)血型抗体效价与新生儿ABO溶血病的临床资料,探究不同IgG血型抗体效价中新生儿ABO溶血病的发生情况。方法 回顾性分析延安大学附属医院2018年1月至2020年12月期间行产前IgG血型抗体效价检测的孕妇200例的临床资料,统计不同产前IgG血型抗体效价中新生儿ABO溶血病的发生情况。结果 经临床统计,200例孕妇中,抗体效价≤1∶64共有100例,占比率为50.00%,其中抗体效价＜1∶64的有52例,占比26.00%,抗体效价为1∶64的共有48例,占比为24.00%;抗体效价为1∶128共有37例,占比18.50%;抗体效价在1∶256共有44例,占比22.00%;抗体效价≥1∶512共有19例,占比9.50%;随着产前IgG血型抗体效价升高,其新生儿ABO溶血病发病率也逐渐增长,发病率由低至高依次为1.92%、12.50%、40.54%、50.00%、68.42%。结论 新生儿ABO溶血病的发生率随着产前IgG血型抗体效价的升高而逐渐增高,其中产前IgG血型抗体效价≥1∶512的孕妇,新生儿ABO溶血病发生率最高。     

藁本内酯抑制RANKL诱导RAW264.7向破骨细胞分化及其与GPER相关机制

目的  观察藁本内酯(LIG)对核因子κB受体活化因子配体(RANKL)诱导RAW264.7向破骨细胞分化的影响,并探讨该作用与G蛋白偶联雌激素受体(GPER)的相关机制。方法  体外培养RAW264.7细胞,RANKL诱导破骨细胞分化,并用LIG进行干预。通过抗酒石酸酸性磷酸酶(TRAP)活性检测和TRAP染色法评价破骨细胞形成和分化能力;qPCR法检测GPER及破骨细胞相关基因mRNA水平;Western blot法检测GPER蛋白表达;采用GPER特异性拮抗剂G36进行干预,观察LIG干预破骨细胞分化的作用变化。结果  LIG浓度为10 μmol/L时,TRAP活性检测结果显示,TRAP活性显著降低(P < 0.01);TRAP染色结果显示,与RANKL组相比,LIG组TRAP阳性细胞形成减少(P < 0.001);qPCR检测结果显示,与RANKL组相比,LIG组树突状细胞-特异性跨膜蛋白(DC-STAMP)、活化T细胞核因子(NFATc1)、组织蛋白酶K(CTSK)和核因子κB受体(RANK)的mRNA水平显著降低(P < 0.05, P < 0.001),而GPER mRNA表达明显升高(P < 0.001);Western blot结果显示,与RANKL组相比,LIG组GPER蛋白表达升高(P < 0.001)。与LIG组比较,LIG+G36组TRAP阳性细胞数升高(P < 0.01),TRAP活性增强(P < 0.05),DC-STAMP、NFATc1、CTSK、RANK mRNA的表达升高(P < 0.05)。结论  LIG能够抑制RANKL诱导RAW264.7向破骨细胞分化,其机制可能是促进GPER表达,减少RANK和下游转录因子NFATc1的表达,抑制破骨细胞分化和骨吸收功能。      

颅脑战创伤机制及救治研究进展

颅脑战创伤（bTBI）是致残、致死率最高的战创伤类型。在机制方面,冲击波损伤及弹道伤是bTBI的特有损伤形式,能通过影响颅内压、空腔效应等机制造成脑组织广泛损伤。分级救治是提高bTBI救治能力,降低死亡率的有效方法。解放军总医院在bTBI治疗的信息化方面进行了多年研究,结合手术机器人、远程手术等新技术,进一步提高了bTBI的救治水平。     

抗VEGF药物玻璃体腔内注射联合23 G玻璃体切除术对增殖性糖尿病视网膜病变患者的疗效分析

目的分析抗血管内皮生长因子(VEGF)药物玻璃体腔内注射联合23 G玻璃体切除术对增殖性糖尿病视网膜病变(PDR)患者的疗效。方法选取2017年1月~2019年1月河南省人民医院88例PDR患者(88只眼),根据治疗方案分组,各44例(44只眼)。对照组给予23 G玻璃体切除术,实验组给予抗VEGF药物玻璃体腔内注射+23 G玻璃体切除术。观察2组手术时间、电凝止血使用率,对比术前术后最佳矫正视力。结果实验组电凝止血使用频率较对照组低,手术时间较对照组短(P<0.05);与对照组比较,术后实验组最佳矫正视力较高(P<0.05);实验组并发症发生率为4.54%,低于对照组18.18%(P<0.05)。结论PDR患者采取抗VEGF药物玻璃体腔内注射和23 G玻璃体切除术联合治疗,可减少并发症,缩短手术时间,提高视力。