The role of the host response in periodontal disease progression: implications for future treatment strategies

Changes in Gingival Crevicular Fluid Endocan (ESM-1) Levels as a Potential Biomarker After Non-Surgical Periodontal Treatment in Periodontitis Patients

Background: This study aimed to investigate endocan (ESM-1) levels in periodontitis patients before and after non-surgical periodontal treatment by analyzing the relationship between vascular endothelial growth factor A (VEGF-A) and tumor necrosis factor-alpha (TNF-α) in gingival crevicular fluid (GCF). Methods: This study included 26 periodontally healthy people as controls (Group 1) and 27 patients with Stage III-Grade B periodontitis (Group 2). Demographic and periodontal variables were assessed. GCF samples were collected from every subject both before and 6 weeks following non-surgical periodontal therapy (NSPT). Using an enzyme-linked immunosorbent test, biomarker levels were determined. Results: The periodontitis patients showed higher ESM-1 levels than the controls, although the difference was not significant (p > 0.005). The ESM-1 levels decreased significantly after treatment (p = 0.001). The VEGF-A levels did not differ significantly between the periodontitis patients and controls (p > 0.005) and decreased non-significantly following treatment (p > 0.005). The TNF-α levels were significantly higher in the periodontitis patients than the controls (p = 0.000) and decreased significantly after treatment (p = 0.000). A significant correlation was found between TNF-α and both probing depth (PD) and interproximal clinical attachment level (iCAL) in the control group (p < 0.05). In the periodontitis group, the VEGF levels were significantly correlated with the gingival index (GI) (p < 0.05). Significant correlations were identified between ESM-1 and VEGF-A and ESM-1 and TNF-α, as well as VEGF-A and TNF-α, in both the control group and following treatment (p < 0.05). Conclusions: ESM-1 and TNF-α levels decreased with non-surgical periodontal treatment in GCF. Within the limits of the study, the findings suggest that ESM-1 levels in periodontal tissues may be an indicator of periodontal disease.

Resolvin E1 and calvarial defects in rats: a comprehensive histological analysis

Bone loss, linked with numerous oral conditions such as periodontal diseases and periimplantitis, poses a significant challenge for dental clinicians. The current study evaluated the in vivo effects of local application of Resolvin E1 (RvE1) on bone regeneration in critical size calvarial defects in rats. Thirty female Wistar rats with 5 mm induced calvarial defects were randomly allocated into four groups: no treatment (negative control, n = 5), treatment using bovine bone grafts (positive control, n = 5), treatment using local delivery of RvE1 (n = 11) and treatment using RvE1 mixed with bovine bone graft (n = 9). After 12 weeks, the animals were sacrificed and the calvarial defects with the adjacent tissues were sectioned en-bloc and prepared for histological examination. A comprehensive qualitative and quantitative histological examination was performed to assess bone regeneration and its relation to the defect, the presence of remnant bone and RvE1 particles, the integration of the native bone with the newly formed bone, bone density and bony trabeculae, the inflammatory reaction, the connective tissue bridging in the defect, and the encapsulating fibrous tissue. Signs of neovascularization, increased cellularity, lack of the organized lamellated appearance of mature bone, disorganized arrangement of osteocytes, osteoblasts and osteoclasts were also assessed. Comparisons of the quantitative values between all studied groups indicated statistically significant differences (p ≤ 0.05) in all parameters except for the increased cellularity and granulation tissue. Histological findings indicate that RvE1 with adjunct bone graft significantly enhanced the bone formation compared to RvE1 or bovine graft alone.

Comparative evaluation of local drug delivery using tetracycline fibers and antimicrobial photodynamic therapy in Stage II Grade B periodontitis: A clinico-microbiological study

Background

Periodontal therapy aims to eliminate the periopathogens involved in disease progression to restore the lost form and function of the tooth-supporting structures. To overcome the drawbacks of conventional treatment, several adjunctive treatment modalities have been successfully used to treat moderate-to-severe periodontal diseases. The present study aims to comparatively evaluate the efficacy of locally delivered tetracycline fibers and antimicrobial photodynamic therapy (PDT) as an adjunct to nonsurgical periodontal treatment, focusing on the possibility of improving the clinical parameters and reducing the microbial load postoperatively.

Materials and Methods

Twenty-two patients with Stage II Grade B periodontitis were divided into two groups: Group A: scaling and root planing (SRP) + locally delivered tetracycline fibers and Group B: SRP + antimicrobial PDT using indocyanine green as photosensitizer. The following clinical parameters were assessed at baseline, 3 months, and 6 months: Gingival index, modified sulcular bleeding index, clinical attachment level, and probing pocket depth. Subgingival plaque samples were obtained for microbial analysis of Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, and Prevotella intermedia at the following periods.

Results

There was significant improvement in clinical and microbiological parameters in both the groups at 3 months and 6 months postoperatively. Microbial recolonization was noted in both the groups, albeit without reaching statistical significance with respect to P. gingivalis and A. actinomycetemcomitans at 6 months postoperatively.

Conclusion

From the results obtained, it can be concluded that both local drug delivery and antimicrobial PDT can be used as an effective adjunctive treatment to SRP. However, supportive periodontal care is required to avoid microbial recolonization.

The impact of Resolvin E1 on bone regeneration in critical-sized calvarial defects of rat model-A gene expression and micro-CT analysis

OBJECTIVE

To investigate, in vivo, the effect of local application of Resolvin E1 (RvE1) on the bone regeneration of critical-size defects (CSDs) in Wistar rats utilizing gene expression and micro-computed tomographic (micro-CT) analysis.

BACKGROUND

The inflammation-resolving actions of RvE1 are well established. The molecular mechanism of its bone-regenerative actions has been of significant interest in recent years; however, there is limited information regarding the same.

MATERIALS AND METHODS

Thirty Wistar rats with a 5 mm induced critical-size calvarial defect were randomly allocated into four groups: no treatment/negative control (n = 5), treatment using bovine bone grafts/positive control (n = 5), treatment using local delivery of RvE1 (n = 11) and treatment using RvE1 mixed with bovine bone graft (n = 9). After 4 weeks, RNA isolation, complementary DNA synthesis and real-time polymerase chain reaction were used for genetic expression of alkaline phosphatase (ALP), osteocalcin (OCN) and osteopontin (OPN). The rats were sacrificed after 12 weeks and micro-CT imaging was performed to analyse the characteristics of the newly formed bone (NFB). The data were analysed using ANOVA and the least significant difference tests (α ≤ .05).

RESULTS

The RvE1 + bovine graft group had statistically highest mean NFB (20.75 ± 2.67 mm3 ) compared to other groups (p < .001). Similarly, RvE1 + bovine graft group also demonstrated statistically highest mean genetic expression of ALP (31.71 ± 2.97; p = .008) and OPN (34.78 ± 3.62; p < .001) compared to negative control and RvE1 groups.

CONCLUSION

Resolvin E1 with adjunct bovine bone graft demonstrated an enhanced bone regeneration compared to RvE1 or bovine graft alone in the calvarial defect of Wistar rats.

The impact of the soluble epoxide hydrolase cascade on periodontal tissues

Periodontitis is a chronic inflammatory disease with complex pathogenesis. Uncontrolled inflammation is driven by the immune system in response to accumulation of oral biofilm that leads to alveolar bone loss, bleeding, increased periodontal probing depth with loss of attachment of the connective tissues to the tooth, and ultimately, tooth loss. Soluble epoxide hydrolase (sEH) is an enzyme that converts epoxy fatty acids (EpFAs) produced by cytochrome P450 (CYP450) to an inactive diol. It has been shown that EpFAs display important features to counteract an exaggerated inflammatory process. Based upon this observation, inhibitors of sEH have been developed and are being proposed as a strategy to regulate proinflammatory lipid mediator production and the chronicity of inflammation. This mini review focuses on the impact of sEH inhibition on periodontal tissues focusing on the mechanisms involved. The interaction between Specialized Pro-Resolving Mediators and sEH inhibition emerges as a significant mechanism of action of sEH inhibitors that was not formerly appreciated and provides new insights into the role SPMs may play in prevention and treatment of periodontitis.

C, Venkata RKS, Penmetsa GS, Koneru S, Pasupuleti S. Estimation of Salivary Neopterin Levels in Aggressive and Chronic Periodontitis After Nonsurgical Periodontal Therapy: A Cohort Study

Aim:

Neopterin is a marker associated with cell-mediated immunity produced by interferon-Ɣ-stimulated macrophages. The levels of neopterin in body fluids are elevated in infections, autoimmune diseases, malignancies, and allograft rejections. Recently, it was shown to be associated with the initiation and progression of periodontal disease. This investigation was designed to explore the use of salivary neopterin in predicting the outcome of nonsurgical periodontal therapy (NSPT) in aggressive and chronic periodontitis patients.

Materials and Methods:

This case-control study with stratified sampling comprised 45 subjects divided into three groups: a control group of 15 periodontally healthy participants, a test Group A of 15 participants with chronic periodontitis, and a test Group B of 15 participants with aggressive periodontitis. Periodontal parameters, including plaque index (PI), gingival index (GI), probing depth (PD), and clinical attachment level (CAL), were recorded at baseline and three months after scaling and root planing (SRP). An enzyme-linked immunosorbent assay (ELISA) analysis was performed to measure neopterin levels in saliva in study groups before and after SRP. Kruskal–Wallis analysis of variance and Mann–Whitney U tests were done for intra- and intergroup comparisons. The correlation between salivary neopterin levels with clinical parameters was done by Karl Pearson’s correlation coefficient.

Results:

Baseline salivary neopterin levels were least in the control group (5 62 nmol/L), higher in test Group A (9.30 nmol/L), and highest in test Group B (9.76 nmol/L). Three months after SRP, there was a significant reduction in all the clinical parameters, and the reduction in mean salivary neopterin levels were 2.79 and 2.57 in test Group A and test Group B, respectively; the difference was not statistically significant.

Conclusion:

Salivary neopterin levels have the potential to be utilized as a diagnostic tool for detecting the presence, activity of the disease, and the course of the lesions. It cannot, however, be utilized to distinguish between chronic and aggressive periodontitis.

Gingival crevicular fluid lipocalin-2 and semaphorin3A in stage III periodontitis: Non-surgical periodontal treatment effects

BACKGROUND AND OBJECTIVE

Identification of biomarkers to assess individual risk and monitor periodontal health status is important. Research on lipocalin-2 (LCN2) and semaphorin3A (Sema3A) is lacking. This study aimed to evaluate gingival crevicular fluid (GCF) LCN2, Sema3A, and tumor necrosis factor-α (TNF-α) levels in periodontally healthy (H), gingivitis (G), and periodontitis (P) patients, and their changes following non-surgical periodontal therapy.

METHODS

Sixty systemically healthy and non-smoker participants, diagnosed as periodontally healthy, gingivitis, and stage III grade C periodontitis, were recruited (n = 20/group). Clinical periodontal parameters were recorded and GCF samples were obtained at baseline from all groups; for group P, these were repeated one and three months following non-surgical periodontal treatment. GCF LCN2, Sema3A, and TNF-α levels were evaluated with enzyme-linked immunosorbent assay.

RESULTS

GCF LCN2, Sema3A, and TNF-α total amounts were significantly higher in disease groups than group H (p < .001). Between P and G groups, only TNF-α levels were significantly different (p < .001). Non-surgical periodontal therapy resulted in significant improvement of all clinical parameters and significant decreases of GCF LCN2 and TNF-α levels, at both time points, compared with baseline (p < .001). Sema3A levels remained unchanged following treatment (p > .05). LCN2 and TNF-α levels were significantly positively correlated with clinical parameters. LCN2 (AUC [area under the curve] = 0.94) and TNF-α (AUC = 0.98) levels were similarly accurate in differentiating between periodontal disease (whether G or P) and healthy controls.

CONCLUSIONS

LCN2 and TNF-α levels in GCF are correlated with clinical parameters and could prove useful as non-invasive screening tools for periodontitis.

Use of water and ethanol extracts from wine grape seed pomace to prepare an antioxidant toothpaste

BACKGROUND

Extracts of fresh wine grape seeds/skin or of grape pomace seeds were used to prepare antioxidant natural toothpastes.

RESULTS

Ethanol extracted twice more polyphenols than water; ultrasound did not provide any improvement in the extraction. The addition of freeze-dried ethanol extracts of seeds or skin, at 2% and 10%, to the commercial toothpaste significantly increased the polyphenol content, both from white grape seeds and skin and from red grape seed pomace. The evaluation of time stability (shelf life) revealed a decrease, after 4 months, of 3.9% and 9.4% in total polyphenol content, in 5% and 10% water extracts, but not for ethanol extracts. 1,1-Diphenyl-2-picrilhydrazil¹ antiradical activity was the highest in 10% of seed water extract toothpaste and, after 4 months, the activity was stable.

CONCLUSION

Ethanol and water are efficient and safe solvents to create natural toothpaste with grape or pomace seed extract with antioxidant activity. © 2021 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Effectiveness of photodynamic therapy as an adjunct to topical antiviral therapy in the treatment of herpes labialis: A randomized controlled clinical trial

BACKGROUND

The present clinical trial assessed the effectiveness of photodynamic therapy in association with topical acyclovir in the treatment of herpes labialis in adolescent patients.

MATERIALS AND METHODS

45 individuals with herpes labialis were divided into three groups on the basis of provision of treatment. (a) Group I: Topical acyclovir therapy (AVT) (n = 15, mean age: 17.5 years) (b) Group 2: photodynamic therapy (PDT) (n = 15, mean age:16.8 years) and (c) Group III: AVT + adjunctive PDT (n = 15, mean age: 17.0 years) respectively. HSV-1 quantification and pain scales [visual analogue scale (VAS) and McGill Pain Questionnaire (MPQ)] were calculated. Pro-inflammatory biomarkers including interleukin (IL-6) and tumor necrosis factor-alpha (TNF-α) were quantified using enzyme linked immunosorbent assay (ELISA). Shapiro-Wilk test was used to assess the normality. The Friedman test was employed to compute the comparison for changes recorded in pain scores, proinflammatory cytokines and HSV-1 quantification, whereas Mann-Whitney test was used to analyze the mean values and establish inter-group comparisons. All assessments were performed at baseline, immediate post op, 2-weeks, 4-weeks, 3-months, and 6-months.

RESULTS

A total of 44 individuals completed the clinical trial. According to the data obtained from the clinical assessment, all the study groups reported a decrease in the parameters being observed. However, Group III (anti-viral (acyclovir) therapy + adjunctive PDT) showed a statistically significant decrease, in comparison to Group II (PDT) and Group I [AVT] respectively. The quantified HSV-1 among all groups showed significant reduction among all groups at each successive follow-up. However, Group-III (AVT + PDT) showed statistically significant reduction as compared to Groups I and II, respectively (p < 0.05).

CONCLUSION

Topical anti-viral therapy with adjunctive PDT significantly helped in reducing the pain and pro-inflammatory biomarkers in adolescent herpes labialis patients.

TNFα expression by Porphyromonas gingivalis-stimulated macrophages relies on Sirt1 cleavage

OBJECTIVE

Periodontitis is one the most common chronic inflammatory conditions, resulting in destruction of tooth-supporting tissues and leading to tooth loss. Porphyromonas gingivalis activates host macrophages to secrete pro-inflammatory cytokines and elicit tissue damage, in part by inducing NF-kappa-B transactivation. Since NFκB transactivation is negatively regulated by the Nicotinamide adenine dinucleotide (NAD)-dependent deacetylase enzyme Sirt1, we sought to assess if RAW264.7 macrophages exposed to P. gingivalis demonstrate impaired Sirt1 activity, to ultimately induce a pro-inflammatory response.

METHODS

RAW264.7 macrophages were incubated with heat- killed P. gingivalis for 2, 4, 8, and 24 h. Stimulated RAW264.7 were assessed for TNFα expression via PCR, ELISA, and ChIP analysis. Following the activation of RAW264.7 macrophages, immunoblot analysis was executed to detect modifications in Sirt1 and the NFκB subunit RelA that is essential for NFκB transcriptional activity.

RESULTS

TNFα expression was elevated 4 h after exposure to P. gingivalis. ChIP confirmed that RelA was enriched in the mouse TNFα promoter 4 h following stimulation, which correlated with the increased TNFα mRNA levels. Preceding TNFα expression, we detected Phosphoserine 536 and acetylated lysine 310 of RelA after 2 hours exposure with P. gingivalis. Moreover, reduced Sirt1 activity was associated with its cleavage in RAW264.7 protein extracts, after 2 hours of P. gingivalis exposure. Blocking TLR2/4 signaling prevented Sirt1 cleavage, loss of deacetylase activity, and TNFα secretion, while co-administering CA074Me (a cathepsin B inhibitor) with P. gingivalis reduced RelA promoter enrichment, resulting in impaired TNFα expression.

CONCLUSIONS

Together, the results suggest that P. gingivalis induces TNFα expression, at least in part, by enhancing cleavage of Sirt1 via a TLR-dependent signaling circuit.

Influence of Natural Killer Cells and Natural Killer T Cells on Periodontal Disease: A Systematic Review of the Current Literature

Natural killer (NK) cells, as members of the innate immune system, and natural killer T (NKT) cells, bridging innate and adaptive immunity, play a prominent role in chronic inflammatory diseases and cancerogenesis, yet have scarcely been examined in oral diseases. Therefore, systematic research on the latest literature focusing on NK/NKT cell-mediated mechanisms in periodontal disease, including the time period 1988-2020, was carried out in MEDLINE (PubMed) using a predetermined search strategy, with a final selection of 25 studies. The results showed that NK cells tend to have rather proinflammatory influences via cytokine production, cytotoxic effects, dendritic-cell-crosstalk, and autoimmune reactions, while contrarily, NKT cell-mediated mechanisms were proinflammatory and immunoregulatory, ranging from protective effects via B-cell-regulation, specific antibody production, and the suppression of autoimmunity to destructive effects via cytokine production, dendritic-cell-crosstalk, and T-/B-cell interactions. Since NK cells seem to have a proinflammatory role in periodontitis, further research should focus on the proinflammatory and immunoregulatory properties of NKT cells in order to create, in addition to antibacterial strategies in dental inflammatory disease, novel anti-inflammatory therapeutic approaches modulating host immunity towards dental health.

Anti-inflammatory effect of glycyrrhizin with Equisetum arvense extract

Periodontal disease is the most prevalent infectious disease, and inflammatory mediators play critical roles in its progression. Therefore, controlling pro-inflammatory cytokine production, especially at initial disease stages, is essential to maintaining gingival and periodontal health. Glycyrrhizin (GL) has an anti-inflammatory effect and has been added to toothpaste and mouth rinse to prevent periodontal disease. However, there is a maximum dose for the use of GL. The aim of the present study is to screen plant extracts which can effectively enhance the effects of GL. The effects of extracts from six different plants on GL-suppressed TNF-α expression in Aggregatibacter actinomycetemcomitans (A.a.)-LPS-stimulated human oral keratinocytes (RT7) were examined. Results demonstrated that Equisetum arvense (EA) extract had the strongest additive effect on the suppression of TNF-α by GL at both mRNA and protein levels. In addition, GL downregulated the production of TNF-α by suppressing NF-κB p65 phosphorylation, but not JNK or p38 phosphorylation. In contrast, EA decreased JNK phosphorylation but not NF-κB p65 or p38 phosphorylation. The combination of GL and EA effectively attenuated A.a.-LPS-induced phosphorylation of NF-κB p65 and JNK. Furthermore, an LPS-induced periodontitis rat model showed that GL with EA supplementation significantly downregulated TNF-α mRNA in the gingival tissue. These results indicate that EA can suppress A.a.-LPS-induced pro-inflammatory cytokine production by inhibiting JNK activation and can promote the anti-inflammatory effects of GL. Our findings suggest that a combination of GL and EA may improve the development of new oral hygiene products aimed at enhancing periodontal health.

Shifting the paradigm from inhibitors of inflammation to resolvers of inflammation in periodontitis

An initial shift in our understanding of the basis of periodontal disease occurred early in the 2000s. The host response, rather than the bacterial burden, was the principal determinant of the disease. Microbial dysbiosis that occurs in periodontal disease results from a hyperinflammatory state in the host. A second shift in periodontal disease is taking place. This time in the realm of treatment strategies. Rather than targeting antimicrobials or inhibitors of individual inflammatory mediators, preclinical studies support using resolution pharmacology to convert the pro-inflammatory condition into a non-inflammatory one, thereby resolving both the local and systemic inflammation associated with periodontal disease. Here, I describe the bases for these shifts in paradigms.

Enhanced dual function of osteoclast precursors following calvarial Porphyromonas gingivalis infection

BACKGROUND AND OBJECTIVE

Excessive osteoclast activity is a major characteristic of pathogenic bone loss in inflammatory bone diseases including periodontitis. However, beyond the knowledge that osteoclasts are differentiated from the monocyte/macrophage lineage and share common ancestry with macrophages and DC, the nature and function of osteoclast precursors are not completely understood. Furthermore, little is known about how osteoclast precursors respond to bacterial infection in vivo. We have previously demonstrated in vitro that the periodontal pathogen Porphyromonas gingivalis (Pg) plays a biphasic role on the receptor activator of nuclear factor kappa B ligand (RANKL)-induced osteoclast differentiation. In this study, we investigated the in vivo effect of Pg infection on the regulation of osteoclast precursors, using a mouse calvarial infection model.

METHODS AND RESULTS

C57BL/6 wild-type and the myeloid differentiation factor 88 knockout (MyD88-/- ) mice were infected with Pg by calvarial injection. Local and systemic bone loss, and the number and function of CD11b+ c-fms+ cells from bone marrow and spleen were analyzed. Our results show that Pg infection induces localized inflammatory infiltration and osteoclastogenesis, as well as increased number and osteoclastogenic potential of CD11b+ c-fms+ osteoclast precursors in the bone marrow and periphery. We also show that CD11b+ c-fms+ RANK+ and CD11b+ c-fms+ RANK- are precursors with similar osteoclastogenic and pro-inflammatory potentials. In addition, CD11b+ c-fms+ cells exhibit an antigen-specific T-cell immune-suppressive activity, which are increased with Pg infection. Moreover, we demonstrate that MyD88 is involved in the regulation of osteoclast precursors upon Pg infection.

CONCLUSIONS

In this study, we demonstrate an enhanced dual function of osteoclast precursors following calvarial Pg infection. Based on our findings, we propose the following model: Pg infection increases a pool of precursor cells that can be shunted toward osteoclast formation at the infection/inflammation sites, while at the same time dampening host immune responses, which is beneficial for the persistence of infection and maintenance of the characteristic chronic nature of periodontitis. Understanding the nature, function, and regulation of osteoclast precursors will be helpful for identifying therapeutic interventions to aid in the control and prevention of inflammatory bone loss diseases including periodontitis.

Niche Specific Microbiota-Dependent and Independent Bone Loss around Dental Implants and Teeth

Oral mucosal homeostasis is achieved by complex immunologic mechanisms, orchestrating host immunity to adapt to the physiologic functions of the various specialized niches in the oral cavity. Dental implants introduce a novel mucosal niche to the immune system to deal with. Nevertheless, the immune mechanisms engaged toward implants and whether they have broader effects are not well defined. Using a murine model, we found an accumulation of neutrophils and RANKL-expressing T and B lymphocytes in the implant-surrounding mucosa, accompanied by local bone loss. Surprisingly, the presence of implants had an impact on remote periodontal sites, as elevated inflammation and accelerated bone loss were detected in intact distant teeth. This was due to microbial dysbiosis induced by the implants, since antibiotic treatment prevented bone loss around teeth. However, antibiotic treatment failed to prevent the loss of implant-supporting bone, highlighting the distinct mechanisms mediating bone loss at each site. Further analysis revealed that implants induced chronic lymphocyte activation and increased mRNA expression of IFN-α and accumulation of IFN-α–producing plasmacytoid dendritic cells, which we previously reported as bone-destructive immune responses. Collectively, this study demonstrates that implants have a strong and broad impact on oral mucosal homeostasis, inducing periodontal bone loss in a niche-specific manner that is both microbiota dependent and independent.

Periodontitis: a host mediated disruption of microbial homeostasis

PURPOSE OF REVIEW

In a prolific scientific career, Dr. Robert J. Genco dedicated himself to enriching our understanding of the pathogenesis of periodontitis. During a period of time in the 1970s and 1980s, when periodontitis was considered a classic infectious disease, Bob had the foresight to investigate and characterize the immune/inflammatory response in periodontitis, particularly Juvenile Periodontitis. His leadership in this area brought to the fore our appreciation of host-microbiome interactions that many years later (2008) culminated in the realization that periodontitis is a fundamental inflammatory disease. In this review, the question of how the host regulates the inflammatory response will be addressed in the context of how more recently-discovered pathways of resolution of inflammation play a role in disease pathogenesis.

RECENT FINDINGS

The host inflammatory response to commensal organisms creates excess inflammation in susceptible individuals and likely drives the dysbiosis of the oral microbiome observed in people with Periodontitis. In periodontal health, the oral microbiome is in balance with the host response. It is the loss of this symbiotic relationship with excess inflammation and microbiome dysbiosis that characterizes progressive disease. In recent years, the role of mediators of resolution of inflammation in the loss of balance and their potential use as therapeutics to restore homeostasis has extended our knowledge of how the host drives immune responses to affect oral dysbiosis.

SUMMARY

Dr. Genco provided the foundation for our ever-emerging understanding host-microbial interactions. The discovery of inflammation resolution pathways has furthered our knowledge in periodontal homeostasis. More studies are needed to understand how the host regulates the microbiome to fulfill the ultimate goal of more efficient therapeutics for periodontitis and related inflammatory diseases.

A disintegrin-like and metalloproteinase with thrombospondin-1 (ADAMTS-1) levels in gingival crevicular fluid correlate with vascular endothelial growth factor-A, hypoxia-inducible factor-1α, and clinical parameters in patients with advanced periodontitis

BACKGROUND

ADAMTS (a disintegrin-like and metalloproteinase with thrombospondin) are a family of proteinases that are structurally similar to the family of matrix metalloproteinases with critical roles in damage and repair of the extracellular matrix. Their functions are closely related to inflammation, hypoxia, and vascularization. Our aim was to determine levels of ADAMTS-1 in gingival crevicular fluid (GCF) in patients with advanced periodontal diseases and identify their association with hypoxia-inducible factor-1alpha (HIF-1α), vascular endothelial growth factor (VEGF-A), and clinical parameters of periodontitis.

METHODS

The study consisted of three groups: healthy individuals (control; n = 20), generalized chronic periodontitis (CP; n = 21), and generalized aggressive periodontitis (GAgP; n = 20). Clinical parameters were measured. Levels of ADAMTS-1, VEGF-A, and HIF-1α in GCF and serum were quantified by enzyme-linked immunosorbent assay (ELISA) and reported as total amounts and concentration.

RESULTS

ADAMTS-1 total amount in GCF were significantly higher in patients with CP and GAgP compared with healthy individuals (P < 0.05). HIF-1α total amount in GCF were also higher in periodontitis groups compared with the control group (P < 0.05). GCF total VEGF-A content was significantly higher in the GAgP group compared with the CP and the controls (respectively; P = 0.023, P = 0.003). There was a significant correlation between ADAMTS-1, VEGF-A, and HIF-1α levels in the GCF and clinical periodontal parameters (probing depth [PD], bleeding on probing [BOP], and clinical attachment loss (CAL); P < 0.05).

CONCLUSION

ADAMTS-1 may play a role in advanced periodontal disease pathogenesis in correlation with tissue hypoxia and vascularization.

Comparative evaluation of subgingivally delivered 1.2% rosuvastatin and 1% metformin gel in treatment of intrabony defects in chronic periodontitis: A randomized controlled clinical trial

BACKGROUND

The aim of this study is to explore and compare the clinical efficacy of locally delivered 1.2% Rosuvastatin (RSV) and 1% Metformin (MF) gel as an adjunct to scaling and root planning (SRP) in the treatment of intrabony defects in chronic periodontitis patients.

METHODS

A total of 90 volunteers were randomly assigned to three treatment groups; 1) SRP plus placebo gel; 2) SRP plus 1.2% RSV gel; 3) SRP plus 1% MF gel. Clinical parameters like modified sulcus bleeding index (mSBI), plaque index (PI), pocket probing depth (PD) and clinical attachment level (CAL) were recorded at baseline, 6 and 12 months and the radiologic assessment of bone defect fill was performed at 6 and 12 months.

RESULTS

mSBI, BP, PD, and CAL were improved in all the groups, however mean reductions in PD, CAL gain, and percentage of bone fill was found to be higher in RSV and MF groups than placebo group at all visits.

CONCLUSION

Adjunctive use of locally delivered 1.2% RSV and 1% MF gel stimulates a significant PD reduction, CAL gains and improved bone fill when compared with placebo gel. Results were significantly better with the use of 1.2% RSV gel than 1% MF gel.

Linkage of Infection to Adverse Systemic Complications: Periodontal Disease, Toll-Like Receptors, and Other Pattern Recognition Systems

Toll-like receptors (TLRs) are a group of pattern recognition receptors (PRRs) that provide innate immune sensing of conserved pathogen-associated molecular patterns (PAMPs) to engage early immune recognition of bacteria, viruses, and protozoa. Furthermore, TLRs provide a conduit for initiation of non-infectious inflammation following the sensing of danger-associated molecular patterns (DAMPs) generated as a consequence of cellular injury. Due to their essential role as DAMP and PAMP sensors, TLR signaling also contributes importantly to several systemic diseases including cardiovascular disease, diabetes, and others. The overlapping participation of TLRs in the control of infection, and pathogenesis of systemic diseases, has served as a starting point for research delving into the poorly defined area of infection leading to increased risk of various systemic diseases. Although conflicting studies exist, cardiovascular disease, diabetes, cancer, rheumatoid arthritis, and obesity/metabolic dysfunction have been associated with differing degrees of strength to infectious diseases. Here we will discuss elements of these connections focusing on the contributions of TLR signaling as a consequence of bacterial exposure in the context of the oral infections leading to periodontal disease, and associations with metabolic diseases including atherosclerosis and type 2 diabetes.

Evaluation of peripheral neutrophil functions in aggressive periodontitis patients and their family members in Indian population: An assessment of neutrophil chemotaxis, phagocytosis, and microbicidal activity

Background

Association of neutrophil function abnormalities with localized aggressive periodontitis (LAP) has been reported in Indian population. There are no published studies on the familial aggregation of aggressive periodontitis (AP) and neutrophil function abnormalities associated with it in Indian population. The present study aimed to assess neutrophil chemotaxis, phagocytosis, and microbicidal activity in AP patients and their family members of Indian origin, who may or may not be suffering from AP.

Materials and Methods

Eighteen families with a total of 51 individuals (18 probands, 33 family members) were included. Neutrophil chemotaxis was evaluated against an alkali-soluble casein solution using Wilkinson's method. Phagocytosis and microbicidal activity assay were performed using Candida albicans as an indicator organism.

Statistical Analysis Used

The magnitude of association between the presence of defective neutrophil function and LAP or GAP was calculated using odds ratio and relative risk. Total incidence of AP, and in particular, LAP in the families attributable to the presence of defective neutrophil function was calculated by attributable risk.

Results

The association between depressed neutrophil chemotaxis and presence of AP and LAP or GAP in all the family members (n = 51) was found to be significant (P < 0.05) while that for phagocytic and microbicidal activity were observed to be nonsignificant.

Conclusion

The results of the present study suggest high incidence of AP (LAP and GAP) within families was associated with depressed neutrophil chemotaxis. High prevalence of depressed neutrophil chemotaxis in the family members (61%) of LAP probands exhibiting depressed chemotaxis suggests that the observed abnormalities in neutrophil functions may also be inherited by the family members.

Effects of photodynamic therapy in periodontal treatment: A randomized, controlled clinical trial

AIM

To evaluate the effects of photodynamic therapy (PDT) in the nonsurgical treatment of chronic periodontitis.

MATERIALS AND METHODS

A randomized, single-blind, controlled, parallel-group clinical trial was performed. Sixty patients were enrolled: 20 healthy controls and 40 patients with periodontitis. The 40 patients were randomized for scaling and root planing (SRP) or SRP + PDT. Periodontal (plaque index, probing depth, clinical recession, clinical attachment level, bleeding on probing and gingival crevicular fluid volume, corresponding to 381 versus 428 critical sites), microbiological (Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, Prevotella intermedia and Campylobacter rectus presence, 18 versus 19 samples) and biochemical (interleukin (IL)-1β, IL-6 and tumour necrosis factor (TNF)-α, receptor activator of nuclear factor-kappaB ligand (RANK-L) and osteoprotegerin (OPG) levels, 18 versus 19 samples) parameters were recorded.

RESULTS

Within each group, significant improvements were found for clinical parameters, though without significant differences between groups. RANK-L was significantly decreased at week 13 in the SRP + PDT group compared with the SRP group. SRP + PDT, but not SRP alone, significantly reduced the abundance of A. actinomycetemcomitans.

CONCLUSIONS

Except for a significant decrease in the pathogenic burden of A. actinomycetemcomitans, coadjuvant PDT resulted in no additional improvement compared with SRP alone in patients diagnosed with moderate-to-advanced chronic periodontitis.

Edema in Oral Mucosa after LPS or Cytokine Exposure

Lowering of interstitial fluid pressure (Pif) is an important factor that explains the rapid edema formation in acute inflammation in loose connective tissues. Lipopolysaccharide (LPS) and the pro-inflammatory cytokines interleukin-1beta (IL-1β) and tumor necrosis factor-alpha (TNF-α) are pathogenetic in gingivitis. To test if these substances induce lowering of Pif in rat oral mucosa, we measured Pif with a micropuncture technique. IL-1β and TNF-α caused lowering of Pif, whereas LPS induced an immediate increase in Pif, followed by lowering after 40 min. Measurements of fluid volume distribution showed a significant change in interstitial fluid volume (Vi) 1.5 hr after LPS exposure as Vi changed from 0.41 ± 0.02 to 0.51 ± 0.03 mL/g wet weight ( p < 0.05), confirming edema. These findings show that LPS, IL-1β, and TNF-α induce lowering of Pif in the rat oral mucosa and contribute to edema formation in LPS-induced gingivitis.

Photodynamic therapy decrease immune-inflammatory mediators levels during periodontal maintenance

Antimicrobial photodynamic therapy (aPDT) was introduced as a promising adjuvant therapy on the periodontal treatment. The aim of this study was to evaluate the effect of aPDT on inflammatory mediator levels in residual periodontal pockets of patients with severe chronic periodontitis under periodontal maintenance, during 12 months follow-up. A randomized controlled trial study was conducted in 28 patients with severe chronic periodontitis. After non-surgical periodontal treatment, patients with at least four teeth with residual pocket probing depth (PPD) ≥4 mm were randomly assigned to either aPDT or control group. The aPDT (low power laser: 660 nm, 40 mW, 90 J/cm², methylene blue 0.01 %) was performed at baseline and 3, 6, and 9 months. Clinical parameters were collected before and 3 and 12 months after the intervention, and gingival crevicular fluid was collected in the same times, including 1 week after the intervention. Immunological evaluation was carried out using the Luminex assay which quantified the expression of ten cytokines: interleukin (IL)-1α, IL-1β, IL-8, IL-1ra, fibroblast growth factor (FGF), vascular endothelial growth factor (VEGF), interferon (IFN)-γ, tumor necrosis factor (TNF)-α, IL-4, and IL-10. All clinical variables showed significant improvement for both groups, but there was no statistical difference between groups with no clinical benefits. IL-1α, IL-1β, IL-8, and VEGF showed significant differences (p < 0.05) between groups, whereas IL-1ra mediators, IFN-γ, and IL-10 demonstrated a statistical difference (p < 0.01) over time in the same group. At any time, FGF, IL-4, and TNF-α showed no statistical difference between groups (p > 0.05). aPDT therapy can improve the benefits on inflammation control during the periodontal maintenance.

Comparative analysis of gingival crevicular fluid β-glucuronidase levels in health, chronic gingivitis and chronic periodontitis

Background and Objectives:

Current methods available for periodontal disease diagnosis are seriously deficient in terms of accuracy, in the ability to predict ongoing or future disease activity and indeed in determining whether previously diseased sites are in an arrested phase or still active. One area that is receiving a great deal of attention is the biochemical investigation of gingival crevicular fluid (GCF). β-glucuronidase (βG) is one of the enzymes found in GCF that is involved in degradation of the ground substance and fibrillar components of host connective tissue. GCF βG activity might be a good indicator or predictor of periodontal disease activity. This study was conducted to estimate and compare the GCF βG levels in patients with healthy periodontium, chronic gingivitis, and chronic periodontitis.

Methodology:

Subjects were classified into three groups of 20 patients each; healthy individuals, chronic gingivitis, and chronic periodontitis. After recording the plaque index, gingival index and probing pocket depth, 1 μL GCF was collected by placing a calibrated microcapillary pipette extracrevicularly and transferred to sterile plastic vials containing 350 μL of normal saline with 1% bovine serum albumin. Analysis of βG was done by spectrophotometry

Results:

βG levels in GCF were significantly higher in chronic periodontitis group (mean value - 2.04743), followed by chronic gingivitis group (mean - 1.11510) and healthy group (0.53643).

Conclusion:

Increased βG levels were observed in patients with increased periodontal destruction, hence GCF βG levels can be used as biochemical marker for periodontal disease activity.

Herbal anti-inflammatory immunomodulators as host modulators in chronic periodontitis patients: a randomised, double-blind, placebo-controlled, clinical trial

PURPOSE

Host modulatory therapy has been proposed as a treatment for periodontal diseases. A class of herbal medicines, known to be immunomodulators, alters the activity of immune function through the regulation of informational molecules such as cytokines. In the current study, we tested the hypothesis that herbal immunomodulator drugs act as an adjuvant to scaling and root planing (SRP) in alleviating periodontal inflammation by improving clinical and biochemical parameters.

METHODS

Sixty healthy subjects (30 in each group) with moderate and severe chronic periodontitis were enrolled in a double-blind, placebo-controlled, double-masked randomised controlled trial. The control group was treated with SRP and a placebo, whereas the test group was treated with SRP followed by dietary supplementation of Septilin for 3 weeks. Periodontal clinical parameters and serum C-reactive protein (CRP) levels were evaluated for all patients at the baseline, 3 weeks, and 6 weeks.

RESULTS

Improved gingival index scores found in the test group as compared to the control group were found to be statistically significant only after 3 weeks (P<0.001). In contrast, the decrease in the sulcus bleeding index and pocket depth scores was statistically highly significant in the test group as compared to the control group after 3 weeks and 6 weeks (P<0.001). However, reduced clinical attachment level and CRP scores, as reflected in the test group as compared to the control group, were not found to be statistically significant after both 3 weeks (P>0.05) and 6 weeks (P>0.05).

CONCLUSIONS

The results of this clinical-biochemical study suggest that dietary supplementation with herbal immunomodulatory agents may be a promising adjunct to SRP and may aid in improving periodontal treatment outcomes.

Assessment of peripheral neutrophil functions in patients with localized aggressive periodontitis in the Indian population

Background:

Localized aggressive periodontitis (LAP) patients exhibit abnormal neutrophil functions to a variety of environmental and host stimuli. The aim of the present study was to evaluate neutrophils chemotaxis, phagocytosis, microbicidal activity and superoxide generation in LAP patients of Indian origin.

Materials and Methods:

Eleven LAP patients and nine healthy subjects were included in the study. Neutrophil chemotaxis was evaluated against an alkali-soluble casein solution using Wilkinson's method. Phagocytosis and microbicidal activity assay were performed using Candida albicans as an indicator organism. Nitrobluetetrazolium (NBT) test was used to assess superoxide generation by neutrophils using E. coli endotoxin.

Results:

The chemotactic activity and phagocytic and microbicidal activity were observed to be significantly reduced (P < 0.01) in LAP neutrophils. On the contrary, superoxide generation was observed to be significantly increased (P < 0.01) in LAP neutrophils compared with healthy individuals.

Conclusion:

The results of the present study suggest that neutrophil functions, namely chemotaxis, phagocytosis and microbicidal activity, are deficient LAP patients. However, superoxide generation was significantly increased when stimulated by endotoxins, which may explain the tissue damage seen in LAP. These abnormal neutrophil functions may predispose to increased susceptibility for LAP. Further large-scale studies are required in the Indian population to ascertain the cause-and-effect relationship of defective host factors and aggressive periodontitis and to develop treatment strategies for more predictable periodontal treatment outcome.

The role of RgpA in the pathogenicity of Porphyromonas gingivalis in the murine periodontitis model

AIM

To investigate the in vivo role of gingipains in Porphyromonas gingivalis' virulence, and suggest a possible host mechanisms through which the bacteria cause alveolar bone loss.

MATERIALS AND METHODS

Mice were orally infected with P. gingivalis wild type, or the gingipains mutants (RgpA⁻, Kgp⁻, RgpA⁻/Kgp⁻). Mice were analysed for alveolar bone loss using micro-computed tomography. The molecular effects of the proteases were evaluated using the subcutaneous chamber model. Mice were infected with P. gingivalis wild type or mutants. Exudates were analysed for cytokine and leukocytes levels, in vivo phagocytosis, P. gingivalis survival and serum anti-P. gingivalis IgG titres.

RESULTS

Only RgpA-expressing bacteria induced significantly alveolar bone loss, and suppressed phagocytosis resulting in increased survival of P. gingivalis in the chamber exudates. In addition, RgpA-expressing bacteria induced higher levels of leukocytes and cytokines 2 h post-infection, and reduced levels of serum anti-P. gingivalis IgG titres 7 days post-infection.

CONCLUSIONS

Our findings showed that elimination of RgpA from P. gingivalis diminished inflammation, but augmented phagocytosis and antibody titres, coincidental with reduced alveolar bone loss. These findings support the hypothesis that RgpA is a critical virulence factor in the pathogenesis of experimental periodontitis in mice.

Porphyromonas gingivalis and Escherichia coli lipopolysaccharide causes resistin release from neutrophils

OBJECTIVES

It was reported that periodontitis is associated with increased serum resistin levels. We examined whether there was a difference between the release of resistin from neutrophils incubated lipopolysaccharide (LPS) from Porphyromonas gingivalis and with LPS from Escherichia coli, and which cell-surface receptors and intracellular kinases were involved in this process.

METHODS

Several concentrations of P. gingivalis-LPS and E. coli-LPS were added to neutrophils, supernatant from cultured neutrophils was collected, and resistin levels were measured by ELISA. To examine signaling pathways, neutrophils were pretreated with monoclonal antibodies against CD14, CD18, TLR2, and TLR4, and specific inhibitors of PI3K and MAPKs.

RESULTS

Resistin release from neutrophils was induced both by P. gingivalis-LPS and E. coli-LPS, but resistin release by P. gingivalis-LPS was weaker than E. coli-LPS in low concentrations. Resistin release was decreased by pretreatment with monoclonal antibodies against CD14, CD18, and TLR4, but not by TLR2. Moreover, it was decreased by inhibitors of PI3K, JNK, and p38 MAPK, but not by ERK1/2.

CONCLUSIONS

Resistin release from neutrophils was induced by both P. gingivalis-LPS and E. coli-LPS. This was decreased by CD14, CD18, and TLR4 and was dependent on PI3K, JNK, and p38 MAPK, but not on ERK1/2 in intracellular pathways of neutrophils.

Direct recognition of Fusobacterium nucleatum by the NK cell natural cytotoxicity receptor NKp46 aggravates periodontal disease

Periodontitis is a common human chronic inflammatory disease that results in the destruction of the tooth attachment apparatus and tooth loss. Although infections with periopathogenic bacteria such as Porphyromonas gingivalis (P. gingivalis) and Fusobacterium nucleatum (F. nucleatum) are essential for inducing periodontitis, the nature and magnitude of the disease is determined by the host's immune response. Here, we investigate the role played by the NK killer receptor NKp46 (NCR1 in mice), in the pathogenesis of periodontitis. Using an oral infection periodontitis model we demonstrate that following F. nucleatum infection no alveolar bone loss is observed in mice deficient for NCR1 expression, whereas around 20% bone loss is observed in wild type mice and in mice infected with P. gingivalis. By using subcutaneous chambers inoculated with F. nucleatum we demonstrate that immune cells, including NK cells, rapidly accumulate in the chambers and that this leads to a fast and transient, NCR1-dependant TNF-α secretion. We further show that both the mouse NCR1 and the human NKp46 bind directly to F. nucleatum and we demonstrate that this binding is sensitive to heat, to proteinase K and to pronase treatments. Finally, we show in vitro that the interaction of NK cells with F. nucleatum leads to an NCR1-dependent secretion of TNF-α. Thus, the present study provides the first evidence that NCR1 and NKp46 directly recognize a periodontal pathogen and that this interaction influences the outcome of F. nucleatum-mediated periodontitis.

Analysis of aspartate aminotransferase in gingival crevicular fluid: A study with initial therapy

Background and Objectives:

Conventional diagnostic indicators cannot distinguish between disease activity and inactivity but can detect the past tissue destruction. A proper and true periodontal diagnosis is essential in order to have a rational treatment and preventive strategy and to identify sites at risk. The present longitudinal study was designed with an aim to examine the relationship between gingival crevicular fluid (GCF) levels of aspartate aminotransferase (AST) and periodontal disease progression and to analyze the level of AST in GCF before and after the initial therapy in chronic periodontitis patients and determine the relationship between AST and conventional measures of periodontal status.

Materials and Methods:

A total of 20 patients with chronic periodontitis were randomly selected. Two diseased sites and one healthy site were selected in each patient. The periodontal status and GCF-AST levels were recorded at baseline and 3 months post-initial therapy and statistically analyzed.

Results:

There was a statistically significant difference in AST levels between diseased periodontal sites and healthy sites (P<0.05), and between baseline and post-initial therapy (P<0.05). Improvements in clinical status were noted following periodontal therapy and there was a corresponding decrease in AST levels.

Interpretation and Conclusion:

In conclusion, it is suggested that AST levels may be a useful adjunct in the clinical assessment of periodontal disease sites since AST level decreases when periodontal status improves.

Myeloperoxidase content is a marker of systemic inflammation in a chronic condition: the example given by the periodontal disease in rats

The study aimed to evaluate the suitability of myeloperoxidase (MPO) content as a local indicator of chronic inflammation, using the periodontal disease model. Anesthetized adult male Holtzman rats had their second left maxilar molar tied by a thread for 11 days and were then killed. Blood samples and photographic images from histopathological inflamed and noninflamed (contralateral) neighboring gingivomucosal specimens were collected for cell counts and MPO level analysis. Diseased animals were also treated with pharmacological tools such as the anti-inflammatory drug celecoxib or the opioid morphine. Increased blood neutrophils and local cell numbers characterized diseased animals. However, local MPO content was increased in inflamed and noninflamed tissues from diseased animals. Celecoxib and morphine reduced blood neutrophils and bilateral MPO content, but only celecoxib reduced local cell numbers in diseased animals. It is concluded that MPO content is a good indicator of a systemic rather than a local inflammation in a chronic inflammatory condition.

Alveolar bone loss in liver transplantation patients: relationship with prolonged steroid treatment and parathyroid hormone levels

AIM

To evaluate the relationship among alveolar bone loss (ABL), bone status and calcium-regulating hormones in liver transplantees.

PATIENTS AND METHODS

Twenty-one liver transplantees underwent a full oral examination. The correlations among bone densitometry, bone metabolic status and drug treatment were examined.

RESULTS

Twelve patients had osteopenia, and six were osteoporotic. ABL was 4.33+/-2.32 mm (range 0.67-9.92). Parathyroid hormone (PTH) levels ranged from 14 to 106 (mean 55.2+/-26.4). The mean 25(OH)D(3) was 11.68+/-4.7, range 3.5-21.1 ng/ml. Nine patients were vitamin D deficient (<10 ng/ml); none of the patients had 25(OH)D(3) levels > or =30 ng/ml. No correlation was found between ABL and current or total glucocorticoids dose, although there was an inverse relation with the duration of treatment (r =-0.474, p=0.03). A positive correlation was found between ABL, PTH (r =0.419, p=0.059) and hip bone mineral density (BMD) (r=0.482, p=0.027). ABL correlated closely with age, PTH, glucocorticoid treatment (duration) and hip BMD (r =0.810, p=0.004).

CONCLUSIONS

The majority of liver transplant patients had insufficient 25(OH)D(3) serum levels. Changes in calcium-regulating hormones and hip BMD were correlated with ABL. Therefore, therapeutic intervention aimed at treating vitamin D deficiency and secondary hyperparathyroidism should be considered in these patients. The benefits of vitamin D treatment in the management of secondary hyperparathyroidism and possible decrease in ABL deserve further evaluation in controlled trials.

Resolvin E1 regulates inflammation at the cellular and tissue level and restores tissue homeostasis in vivo

Resolvin E1 (RvE1) is a potent proresolving mediator of inflammation derived from omega-3 eicosapentaenoic acid that acts locally to stop leukocyte recruitment and promote resolution. RvE1 displays potent counter-regulatory and tissue-protective actions in vitro and in vivo. Periodontal disease is a local inflammatory disease initiated by bacteria characterized by neutrophil-mediated tissue injury followed by development of a chronic immune lesion. In this study, we report the treatment of established periodontitis using RvE1 as a monotherapy in rabbits compared with structurally related lipids PGE(2) and leukotriene B(4). PGE(2) and leukotriene B(4) each enhanced development of periodontitis and worsened the severity of disease. Promotion of resolution of inflammation as a therapeutic target with RvE1 resulted in complete restoration of the local lesion, and reduction in the systemic inflammatory markers C-reactive protein and IL-1beta. This report is the first to show that resolution of inflammation by a naturally occurring endogenous lipid mediator results in complete regeneration of pathologically lost tissues, including bone.

IL-10 gene transfer attenuates P. gingivalis-induced inflammation

IL-10 is an anti-inflammatory cytokine secreted by stimulated Th2 lymphocytes that can down-regulate inflammatory responses to bacterial challenge. We hypothesized that local delivery of IL-10 using gene-transfer will down-regulate inflammatory responses. We examined the effect of IL-10 plasmid injection on the local cytokine response. Two weeks after the implantation of chambers, either IL-10 plasmid or vector was injected into the mice. Four days later, they were challenged with an intra-chamber injection of P. gingivalis. The intra-chamber levels of IL-10, IFNgamma, TNFalpha, and IL-1beta were evaluated after 2 and 24 hrs. The results showed that local IL-10 gene delivery elevated the levels of IL-10 at both time periods. It attenuated the levels of IFNgamma (656 +/- 154 to 218 +/- 144 pg/mL) and TNFalpha (23 +/- 2.0 to 12.5 +/- 2.9 ng/mL) at 2 hrs, and of IL-1beta (21.5 +/- 5.7 to 12.4 +/- 3.0 ng/mL) at 24 hrs. The results suggest the possibility of modulating the local inflammatory response to P. gingivalis by direct IL-10 gene transfer.

Salivary thiols and enzyme markers of cell damage in periodontal disease

OBJECTIVES

Recent studies describe the potential use of biochemical markers in the evaluation of the severity of periodontitis; moreover, patients suffering from periodontitis frequently complain of halitosis (breath malodour), mainly depending on volatile compounds (e.g. hydrogen sulphide, methyl mercaptan, etc.) produced by anaerobic metabolism of oral bacteria and involving sulphur-containing amino acids. In this study, salivary sulphur compounds, such as cysteine, cysteinylglycine and glutathione and some markers of cellular damage (lactate dehydrogenase and aspartate amino transferase), were measured in periodontitis patients and correlated with the periodontal probing pocket's depth.

DESIGN AND METHODS

Twenty-two periodontitis patients and forty control subjects were studied for the salivary activities of lactate dehydrogenase and aspartate aminotransferase and cysteine, cysteinylglycine and glutathione concentrations. The periodontitis patients were divided into two subgroups based on the severity of periodontal disease, expressed as median periodontal probing pocket depth (> or <5 mm). Enzyme activities were measured by using an automated clinical analyzer; cysteine, cysteinylglycine and glutathione concentrations were measured by HPLC equipped with fluorescence detector.

RESULTS

A statistically significant increase of the salivary parameters level (cysteine, cysteinylglycine, glutathione, aspartate aminotransferase and lactate dehydrogenase) was found in the patient subgroup with periodontal probing pocket depth >5 mm, the salivary cysteine concentrations showing the most significant correlation.

CONCLUSIONS

Salivary cysteine, a direct precursor of hydrogen sulphide, could be considered reliable markers for the oral tissue damage severity in periodontitis patients.