口腔扁平苔藓与丙型肝炎病毒感染关系的探讨

目的 :研究丙型肝炎病毒感染与口腔扁平苔藓发病之间的关系。方法 :采用ELISA法检测 31例OLP患者和 71例正常对照组血清中HCV-Ab阳性率。结果 :31例OLP患者中 5例HOV-Ab阳性 (阳性率16.13% ) ,正常组阳性率为零 (p <0.01) ,并且糜烂型OLP患者HCV-Ab阳性率高于非糜烂型患者。结论 :HCV感染与OLP存在相关性。     

Association of dental caries and salivary sIgA with tobacco smoking

Background

Salivary secretory IgA (sIgA) is said to play an important role in the immune response against dental caries. This study aimed to determine the salivary sIgA levels in healthy smokers and non‐smokers, and its correlation with dental caries.

Methods

A total of 70 healthy subjects were selected and classified into four groups according to dental caries and tobacco smoking habits: smoking with caries (Group 1, n = 15); smoking without caries (Group 2, n = 15); non‐smoking with caries (Group 3, n = 15); and non‐smoking without caries (Group 4, n = 25). Salivary sIgA was measured using ELISA. The fissure and proximal caries were examined clinically and radiographically. Caries status was determined according to the decay surface index.

Results

Smokers showed a higher number of caries and the lowest concentration of sIgA. The highest levels of sIgA were observed in non‐smoking and caries‐free subjects compared to caries‐active smokers (123.2 ± 19.9 vs. 13.3 ± 4.1 μg/ml respectively, p < 0.001). Also, the mean level of sIgA in Group 4 was significantly higher than Group 3 (p = 0.009). More importantly, higher and significant levels of sIgA were found in Group 3 versus Group 1 (p < 0.0001) and Group 2 (p = 0.0004).

Conclusions

Our findings indicate that low concentrations of salivary sIgA are correlated with a higher prevalence of dental caries in smokers.     

Inhibition of autophagy augments chemotherapy in human salivary adenoid cystic carcinoma

Although cisplatin (DDP)‐based adjuvant chemotherapy is widely used in the treatment of salivary adenoid cystic carcinoma (SACC), SACCs have developed resistance to cisplatin, resulting in chemotherapy failure. Autophagy serves as a critical adaptive response, which was increased in tumor cells in chemotherapy. However, the function of autophagy is not clear in SACC. In this study, apoptosis induced by DDP in SACC high metastatic cell line (ACC‐M) was revealed using MTT assay, flow cytometry, and caspase‐3 immunoblotting. The autophagy activation induced by DDP treatment was measured by transmission electron microscopy, green fluorescent protein–light chain 3 plasmid transfection LC3 immunoblotting and p62 immunoblotting. 3‐methyladenine (3‐MA) or small interference RNA targeting beclin 1 (beclin 1 siRNA) inhibited autophagy and significantly enhanced DDP‐induced apoptosis. ACC‐M xenografts in nude mice further verified the synergistic effect of DDP and 3‐MA. In conclusion, autophagy activation was caused to protect cancer cells from DDP‐induced apoptosis and autophagy inhibition could be a promising strategy for adjuvant chemotherapy in SACC.     

Current ideas to reduce or salvage radiation damage to salivary glands

Radiation‐induced hyposalivation is still a major problem after radiotherapy for head and neck cancer. Current and promising new thoughts to reduce or salvage radiation damage to salivary gland tissue are explored. The main cause underlying radiation‐induced hyposalivation is a lack of functional saliva‐producing acinar cells resulting from radiation‐induced stem cell sterilization. Current methods to prevent that damage are radiation techniques to reduce radiation‐injury to salivary gland tissue, surgical techniques to relocate salivary glands to a region receiving a lower cumulative radiation dose, and techniques to make salivary gland cells more resistant to radiation injury. These preventive techniques cannot be applied in all cases, also reduce tumor sensitivity, or do not result in a sufficient amelioration of the dryness‐related complaints. Therefore, alternative methods on techniques to salvage salivary glands that are damaged by radiation are explored with promising results, such as stem cell therapies and gene transfer techniques to allow the radiation‐injured salivary gland tissue to secrete water.     

Effect of salivary agglutination on oral streptococcal clearance by human polymorphonuclear neutrophil granulocytes

Salivary agglutination is an important host defense mechanism to aggregate oral commensal bacteria as well as invading pathogens. Saliva flow and subsequent swallowing more easily clear aggregated bacteria compared with single cells. Phagocytic clearance of bacteria through polymorphonuclear neutrophil granulocytes also seems to increase to a certain extent with the size of bacterial aggregates. To determine a connection between salivary agglutination and the host innate immune response by phagocytosis, an in vitro agglutination assay was developed reproducing the average size of salivary bacterial aggregates. Using the oral commensal Streptococcus gordonii as a model organism, the effect of salivary agglutination on phagocytic clearance through polymorphonuclear neutrophil granulocytes was investigated. Here we describe how salivary aggregates of S. gordonii are readily cleared through phagocytosis, whereas single bacterial cells showed a significant delay in being phagocytosed and killed. Furthermore, before phagocytosis the polymorphonuclear neutrophil granulocytes were able to induce a specific de‐aggregation, which was dependent on serine protease activity. The data presented suggest that salivary agglutination of bacterial cells leads to an ideal size for recognition by polymorphonuclear neutrophil granulocytes. As a first line of defense, these phagocytic cells are able to recognize the aggregates and de‐aggregate them via serine proteases to a more manageable size for efficient phagocytosis and subsequent killing in the phagolysosome. This observed mechanism not only prevents the rapid spreading of oral bacterial cells while entering the bloodstream but would also avoid degranulation of involved polymorphonuclear neutrophil granulocytes, so preventing collateral damage to nearby tissue.     

Differential profiles of salivary proteins with affinity to Streptococcus mutans lipoteichoic acid in caries‐free and caries‐positive human subjects

Streptococcus mutans is a representative oral pathogen that causes dental caries and pulpal inflammation. Its lipoteichoic acid (Sm.LTA) is known to be an important cell‐wall virulence factor involved in bacterial adhesion and induction of inflammation. Since Sm.LTA‐binding proteins (Sm.LTA‐BPs) might play an important role in pathogenesis and host immunity, we identified the Sm.LTA‐BPs in the saliva of caries‐free and caries‐positive human subjects using Sm.LTA‐conjugated beads and LTQ‐Orbitrap hybrid Fourier transform mass spectrometry. Sm.LTA was conjugated to N‐hydroxysuccinimidyl‐Sepharose^® 4 Fast Flow beads (Sm.LTA‐beads). Sm.LTA retained its biological properties during conjugation, as determined by the expression of nitric oxide and interferon‐γ‐inducible protein 10 in a murine macrophage cell line and activation of Toll‐like receptor 2 (TLR2) in CHO/CD14/TLR2 cells. Sm.LTA‐BPs were isolated from pooled saliva prepared from 10 caries‐free or caries‐positive human subjects each, electrophoresed to see their differential expression in each group, and further identified by high‐resolution mass spectrometry. A total of 8 and 12 Sm.LTA‐BPs were identified with statistical significance in the pooled saliva from the caries‐free and caries‐positive human subjects, respectively. Unique Sm.LTA‐BPs found in caries‐free saliva included histone H4, profilin‐1 and neutrophil defensin‐1, and those in caries‐positive saliva included cystatin‐C, cystatin‐SN, cystatin‐S, cystatin‐D, lysozyme C, calmodulin‐like protein 3 and β‐actin. The Sm.LTA‐BPs found in both groups were hemoglobin subunits α and β, prolactin‐inducible protein, protein S100‐A9, and SPLUNC2. Collectively, we identified Sm.LTA‐BPs in the saliva of caries‐free and caries‐positive subjects, which exhibit differential protein profiles.     

Alpha‐amylase is a human salivary protein with affinity to lipopolysaccharide of Aggregatibacter actinomycetemcomitans

Aggregatibacter actinomycetemcomitans lipopolysaccharide (Aa.LPS) is a major virulence factor associated with aggressive periodontitis. Although the recognition of Aa.LPS is potentially initiated by salivary proteins in the oral cavity, Aa.LPS‐binding proteins (Aa.LPS‐BPs) in saliva are poorly characterized. The purpose of this study was to capture and identify Aa.LPS‐BPs in human saliva using a LTQ‐Orbitrap hybrid Fourier transform mass spectrometry. Aa.LPS conjugated onto N‐hydroxysuccinimidyl‐Sepharose^® 4 Fast Flow beads (Aa.LPS‐beads) activated Toll‐like receptor 4 and produced nitric oxide and Interferon gamma‐inducible protein‐10, implying that the conjugation process did not alter the biological properties of Aa.LPS. Aa.LPS‐BPs were subsequently isolated from the nine human saliva samples from healthy individuals with the Aa.LPS‐beads followed by identification with the mass spectrometry. Aa.LPS‐BPs include α‐amylase, serum albumin, cystatin, lysozyme C, submaxillary gland androgen‐regulated protein 3B, immunoglobulin subunits, polymeric immunoglobulin receptor, deleted in malignant brain tumors 1, prolactin‐inducible protein, lipocalin‐1, and basic salivary proline‐rich protein 2. Specific binding was validated using a pull‐down assay with α‐amylase which was captured at the highest frequency. Alpha‐amylase demonstrated to interfere with the adherence and biofilm formation of A. actinomycetemcomitans. Even heat‐inactivated α‐amylase showed the interference to the same extent. Conclusively, we identified unique Aa.LPS‐BPs that provide useful information to understand bacterial pathogenesis and host innate immunity in the oral cavity.     

Adherence of Candida albicans to silicone is promoted by the human salivary protein SPLUNC2/PSP/BPIFA2

Interactions between Candida albicans, saliva and saliva‐coated oral surfaces are initial events in the colonization of the oral cavity by this commensal yeast, which can cause oral diseases such as candidiasis and denture stomatitis. Candida albicans also colonizes silicone voice prostheses, and the microbial biofilm formed can impair valve function, necessitating frequent prosthesis replacement. We have previously shown that saliva promoted binding of C. albicans cells to silicone in vitro, and that the selective binding of specific salivary proteins to voice prosthesis silicone mediated attachment of C. albicans cells. The C. albicans cells adhered to a polypeptide (or polypeptides) of ~36 kDa eluted from saliva‐treated silicone. We show here that a protein of similar size was identified in replicate blots of the eluate from saliva‐treated silicone when the blots were probed with antibodies to human SPLUNC2, a salivary protein with reported microbial agglutination properties. In addition, SPLUNC2 was depleted from saliva that had been incubated with silicone coupons. To determine whether SPLUNC2 is a yeast‐binding protein, SPLUNC2 cDNA was expressed in Escherichia coli. Purified recombinant His‐tagged protein (SPLUNC2r) bound to silicone as demonstrated by immunoblot analysis of an eluate from SPLUNC2r‐treated silicone coupons and ³⁵S‐radiolabelled C. albicans cells adhered in a dose‐dependent manner to SPLUNC2r‐coated silicone. We conclude that SPLUNC2 binds to silicone and acts as a receptor for C. albicans adherence to, and subsequent colonization of, voice prosthesis silicone.