Effect of E. faecalis on the release of serine proteases elastase and cathepsin G, and collagenase-2 (MMP-8) by human polymorphonuclear leukocytes (PMNs)

Molecular forms and fragments of salivary MMP-8 in relation to periodontitis

AIM

To investigate the molecular forms of salivary matrix metalloproteinase (MMP)-8 in relation to periodontitis.

MATERIALS AND METHODS

Molecular forms, degree of activation and fragmentation of neutrophilic and mesenchymal-type MMP-8 isoforms were analysed from salivary samples of 81 subjects with generalized periodontitis, 63 subjects with localized periodontitis and 79 subjects without pocket teeth, by using western-immunoblots with computer quantitation. In addition, human recombinant proMMP-8 was in vitro activated by Treponema denticola chymotrypsin-like protease (Td-CTLP), sodium hypochlorite (NaOCl, 1 mM, oxidant) or amino phenyl mercuric acetate (APMA, 1 mM).

RESULTS

In saliva of periodontitis-affected individuals, MMP-8 is found in multiple forms, that is, complexes, active and pro-forms of neutrophilic and mesenchymal-type MMP-8, and especially 20-27 kDa fragments. The quantity of these fragments was elevated in both localized and generalized forms of periodontitis. Moreover, the tested activators (Td-CTLP, NaOCl and APMA) activated inactive proMMP-8, resulting in fragments of 20-27 kDa, in vitro, and salivary concentrations of T. denticola correlated significantly with salivary levels of fragmented MMP-8.

CONCLUSION

The present results indicate that during the development and progression of periodontitis, MMP-8 appears as activated and fragmented, and treponemal proteases most likely play role in this cascade.

Incorporating Antimicrobial Nanomaterial and its Effect on the Antimicrobial Activity, Flow and Radiopacity of Endodontic Sealers

Objective:

This preliminary study aimed to evaluate the antimicrobial activity, flow and radiopacity of endodontic sealers with nanostructured silver vanadate decorated with silver nanoparticles (AgVO3).

Methods:

The minimum inhibitory concentration (MIC) of AgVO3 was evaluated against Enterococcus faecalis, Pseudomonas aeruginosa and Escherichia coli. Specimens were prepared from the following endodontic sealers: AH Plus (DENTSPLY DeTrey GmbH, Konstanz, Germany), Sealapex (Sybron Endo, Orange, CA, USA), Sealer 26 (DENTSPLY, Petrópolis, Brazil) and Endofill (DENTSPLY, Petrópolis, Brazil), with concentrations of 0%, 2.5%, 5% and 10% of AgVO3. Agar diffusion was used to evaluate the materials after 48 hours and 7 days (n=6). Flow (n=6) and radiopacity (n=9) were evaluated. The data were analysed by analysis of variance (ANOVA) and the Tukey honestly significant difference (HSD) (α=0.05).

Results:

The MIC of AgVO3 was 500 μg/mL for E. faecalis and 31.25 μg/mL for P. aeruginosa and E. coli. The AgVO3 did not influence the antimicrobial activity of AH Plus against E. faecalis (P>0.05) but did promote this activity for Sealapex (P<0.01). Moreover, this activity increased for Endofill from 2.5% and for Sealer 26 from 5% (P<0.05). Against P. aeruginosa, only AH Plus and Endofill 10% inhibited zone formation (P<0.01). The antimicrobial activity of Endofill increased from 2.5% against E. coli (P<0.01). Sealapex 5% and 10% (P<0.01), Sealer 26 10% and AH Plus promoted antimicrobial activity against E. coli. An increase in the zone of inhibition occurred between 48 hours and 7 days in the Sealapex 10% and Endofill 5% groups against E. coli. The flow of AH Plus and Endofill decreased with the increase of AgVO3 (P<0.05), and the flow of Sealer 26 and Sealapex was not affected (P>0.05). The radiopacity of AH Plus increased with AgVO3 (P<0.05). Endofill 5% and 10% did not differ from the control Endofill (P>0.05). The incorporation of AgVO3 did not influence the radiopacity of Sealer 26 (P>0.05). The incorporation of 2.5% and 5% AgVO3 reduced the radiopacity of Sealapex (P<0.05).

Conclusion:

Adding AgVO3 may increase the antimicrobial effect of endodontic sealers without major changes in their physicochemical properties.

Targeted delivery of vascular endothelial growth factor improves stem cell therapy in a rat myocardial infarction model

Rebuilding of infarcted myocardium by mesenchymal stem cells (MSCs) has not been successful because of poor cell survival due in part to insufficient blood supply after myocardial infarction (MI). We hypothesize that targeted delivery of vascular endothelial growth factor (VEGF) to MI can help regenerate vasculature in support of MSC therapy in a rat model of MI. VEGF-encapsulated immunoliposomes targeting overexpressed P-selectin in MI tissue were infused by tail vein immediately after MI. One week later, MSCs were injected intramyocardially. The cardiac function loss was moderated slightly by targeted delivery of VEGF or MSC treatment. Targeted VEGF+MSC combination treatment showed highest attenuation in cardiac function loss. The combination treatment also increased blood vessel density (80%) and decreased collagen content in post-MI tissue (33%). Engraftment of MSCs in the combination treatment group was significantly increased and the engrafted cells contributed to the restoration of blood vessels.

FROM THE CLINICAL EDITOR

VEGF immunoliposomes targeting myocardial infarction tissue resulted in significantly higher attenuation of cardiac function loss when used in combination with mesenchymal stem cells. MSCs were previously found to have poor ability to restore cardiac tissue, likely as a result of poor blood supply in the affected areas. This new method counterbalances that weakness by the known effects of VEGF, as demonstrated in a rat model.

Pathogenesis of apical periodontitis: a literature review

OBJECTIVES

This review article discusses the host response in apical periodontitis with the main focus on cytokines, produced under this pathological condition and contributing to the degradation of periradicular tissues. The pace of research in this field has greatly accelerated in the last decade. Here we provide an analysis of studies published in this area during this period.

MATERIAL AND METHODS

Literature was selected through a search of PubMed electronic database. The keywords used for search were pathogenesis of apical periodontitis cytokines, periapical granuloma cytokines, inflammatory infiltrate apical periodontitis. The search was restricted to English language articles, published from 1999 to December 2010. Additionally, a manual search in the cytokine production, cytokine functions and periapical tissue destruction in the journals and books was performed.

RESULTS

In total, 97 literature sources were obtained and reviewed. The topics covered in this article include cellular composition of an inflammatory infiltrate in the periapical lesions, mechanisms of the formation of the innate and specific immune response. Studies which investigated cytokine secretion and functions were identified and cellular and molecular interactions in the course of apical periodontitis described.

CONCLUSIONS

The abundance and interactions of various inflammatory and anti-inflammatory molecules can influence and alter the state and progression of the disease. Therefore, periapical inflammatory response offers a model, suited for the study of many facets of pathogenesis, biocompatibility of different materials to periapical tissues and development of novel treatment methods, based on the regulation of cytokines expression.

Role of polymorphonuclear neutrophils in the clearance of Enterococcus faecalis derived from saliva and infected root canals

OBJECTIVES

The goal of this study was to measure (1) the ability of polymorphonuclear neutrophil leukocytes (PMNs) to kill oral Enterococcus faecalis strains, (2) up-regulation of inflammatory mediators by PMNs in interaction with E. faecalis, and (3) the ability of E. faecalis to cause inflammation in mouse muscle tissue.

METHODS

Fifteen endodontic and nine saliva strains of E. faecalis were isolated and identified by specific 16S ribosomal RNA (16S rRNA) primers. The bacteria were grown in BHI broth and incubated with mouse PMN in appropriate media to determine the ability of the PMNs to kill the bacteria. In other experiments up-regulation of interleukin (IL)-1α, tumor necrosis factor α (TNF-α), matrix metalloproteinase-8 (MMP-8), and cyclooxygenase (COX)-2 messenger RNA in the PMNs was measured after exposure of the leukocytes to the bacteria using real-time polymerase chain reaction. Finally, the inflammatory potential of and PMN response to E. faecalis suspension in mouse muscle tissue was examined from histological sections using hematoxylin-eosin staining and immunostaining.

RESULTS

Murine PMNs killed about 80% of the E. faecalis cells in 1 hour, irrespective of the source of isolation of the strains. Quantitative PCR results showed that IL-1α, TNF-α, MMP-8, and COX-2 messenger RNA were markedly up-regulated in E. faecalis-stimulated PMNs or in E. faecalis-invaded muscular tissues. MMP-8 messenger RNA level was positively related to COX-2 messenger RNA level. Histological evaluation and immunostaining disclosed that all E. faecalis strains could recruit PMNs to the local infectious sites and cause abscess formation.

CONCLUSION

E. faecalis strains from saliva and infected root canals have the potential to recruit PMNs in the infectious sites leading to inflammation via up-regulation of PMN IL-1α, TNF-α, MMP-8, and COX-2. PMNs can play an important role in killing of E. faecalis.