Milestones in periodontal research and the remaining critical issues

Involvement of the endocannabinoid system in current and recurrent periodontitis: A human study

OBJECTIVE

The aim of the present study was to assess if the endocannabinoid system is involved differently in patients with recurrent and non-recurrent periodontal disease and if in sites that have a predisposition for reactivation, levels of anandamide (AEA) change after periodontal therapy.

BACKGROUND

Periodontal disease (PD) may be due to a dysregulation of the endocannabinoid system.

METHODS

Periodontal patients were recruited, treated for PD and monitored. Gingival samples from these patients with recurrent (n = 10) and non-recurrent (n = 10) periodontal disease were harvested before and after treatment and compared to those of periodontally healthy (n = 10) subjects. Levels of CB1 and CB2, AEA and CBs receptor activation were assessed in healthy and inflamed samples using immunohistochemistry, chromatography and autoradiography. In healed sites, AEA levels were also assessed.

RESULTS

The number of CBs in inflamed sites of recurrent patients was significantly higher than in those with non-recurrent disease and also higher than those in healthy subjects. Inflamed sites of recurrent patients had significantly lower CBs receptor activation than those of healthy subjects. Levels of AEA in inflamed sites of non-recurrent patients were significantly higher than those found both in inflamed recurrent sites and in healthy sites. Otherwise, the amount of AEA in healthy subjects and recurrent inflamed sites was similar. After periodontal therapy, levels of AEA were significantly lower in both periodontal groups. In recurrent sites, they resulted significantly lower than in non-recurrent and even in healthy subjects.

CONCLUSIONS

The endocannabinoid system seems involved differently in subjects with recurrent and non-recurrent periodontal disease.

The ever-changing landscape in modern dentistry therapeutics - Enhancing the emptying quiver of the periodontist

Introduction/Objectives

Periodontitis comprises of a wide range of inflammatory conditions of the gums leading to soft tissue damage and attachment loss. The initiation of periodontitis constitutes a rather complex disease pathogenesis which is based on pathogenic shifts of the oral microbiota combined with the host-microbiome interactions. The severity of the periodontitis is multifactorial depending on genetic, environmental, as well as host immunity factors.

Data and sources

To make an inclusive analysis on the periodontitis therapeutics, reading of the recent relevant literature was carried out using the MEDLINE/PubMed database, Google Scholar and the NIH public online database for clinical trials (http://www.clinicaltrials.gov).

Conclusions

Tackling the inflammation associated periodontal defects can be succeeded with conventional therapy or resective and regenerative treatment. To date, the mechanical removal of the supragingival and subgingival biofilm is considered the “gold standard” of periodontal therapy in combination with the use of antibacterial compounds. The antimicrobial resistance phenomenon tends to turn all the currently applied antibacterials into “endangered species”. Ongoing efforts through the conduct of clinical trials should be focused on understanding the advantages of modern approaches in comparison to traditional therapies.

Cytokines and Their Genetic Polymorphisms Related to Periodontal Disease

Periodontal disease (PD) is a chronic inflammatory disease caused by the accumulation of bacterial plaque biofilm on the teeth and the host immune responses. PD pathogenesis is complex and includes genetic, environmental, and autoimmune factors. Numerous studies have suggested that the connection of genetic and environmental factors induces the disease process leading to a response by both T cells and B cells and the increased synthesis of pro-inflammatory mediators such as cytokines. Many studies have shown that pro-inflammatory cytokines play a significant role in the pathogenesis of PD. The studies have also indicated that single nucleotide polymorphisms (SNPs) in cytokine genes may be associated with risk and severity of PD. In this narrative review, we discuss the role of selected cytokines and their gene polymorphisms in the pathogenesis of periodontal disease.

Reversine inhibits MMP-3, IL-6 and IL-8 expression through suppression of ROS and JNK/AP-1 activation in interleukin-1β-stimulated human gingival fibroblasts

OBJECTIVE

Periodontitis is an inflammatory disease of the supporting tissue around teeth commonly caused by gram-negative bacterial infections. Interleukin (IL)-1β, a cytokine involved in host immune and inflammatory responses, is known to induce the activation of various intracellular signaling pathways. One of these signaling mechanisms involves the regulation of gene expression by activation of transcription factors (AP-1 and NF-κB). These transcription factors are controlled by mitogen-activated protein kinases (MAPKs), which increase cytokine and matrix metalloproteinase (MMP) expression. We examined the preventive effects of reversine, a 2,6-disubstituted purine derivative, on cytokine and MMP-3 expression in human gingival fibroblasts (HGFs) stimulated with IL-lβ.

STUDY DESIGN

Western blot analyses were performed to verify the activities of MAPK, p65, p50, and c-Jun and the expression of MMPs in IL-1β-stimulated HGFs. Cytokine and MMP-3 expression in IL-1β-stimulated HGFs was measured by real-time quantitative polymerase chain reaction.

RESULTS

Reversine decreased the IL-1β-induced expression of proinflammatory cytokines (IL-6 and IL-8) and MMP-3 in HGFs. Furthermore, the mechanism underlying the effects of reversine involved the suppression of IL-1β-stimulated MAPK activation and AP-1 activation.

CONCLUSION

Reversine inhibits IL-1β-induced MMP and cytokine expression via inhibition of MAPK/AP-1 activation and ROS generation. Therefore, we suggest that reversine may be an effective therapeutic candidate for preventing periodontitis.

Preventive effects of the novel antimicrobial peptide Nal-P-113 in a rat Periodontitis model by limiting the growth of Porphyromonas gingivalis and modulating IL-1β and TNF-α production

Background

P-113 (AKRHHGYKRKFH-NH2) is a 12-amino-acid histidine-rich peptide derived from histatin 5 that is highly degradable in high salt concentrations and biological fluids such as serum, plasma and saliva. Nal-P-113, a novel antimicrobial peptide whose histidine residues are replaced by the bulky amino acids β-naphthylalanine, causes the antimicrobial peptide to retain its bactericidal activity even in physiological environments. This study evaluated the effect of the novel antimicrobial peptide Nal-P-113 in a rat periodontitis model and the mechanisms of action of Nal-P-113 for suppressing periodontitis.

Methods

Periodontitis was induced in mandibular first molars in rats receiving a ligature and infected with Porphyromonas gingivalis. Animals were randomly divided into six groups: a, P. gingivalis W83 alone; b, P. gingivalis W83 with 6.25 μg/mL of Nal-P-113; c, P. gingivalis W83 with 25 μg/mL of Nal-P-113; d, P. gingivalis W83 with 100 μg/mL of Nal-P-113; e, P. gingivalis W83 with 400 μg/mL of Nal-P-113; and f, control without P. gingivalis W83 or Nal-P-113. Morphometric analysis was used to evaluate alveolar bone loss. Microbiological assessment of the presence of Porphyromonas gingivalis and total bacteria was performed using absolute quantitative real-time PCR and scanning electron microscopy. Gingival tissue was collected for western blot and immunohistochemical assays of IL-1β and TNF-α levels.

Results

Alveolar bone loss was inhibited by 100 μg/mL or 400 μg/mL of Nal-P-113 compared to the control group (P < 0.05). Lower amounts of P. gingivalis and total bacteria were found in groups d and e compared with group a (P < 0.05). A decrease in the levels of IL-1β and TNF-α was detected in group d and group e compared to the control group (P < 0.05). The amount of P. gingivalis was positively correlated with IL-1β and TNF-α expression in periodontal tissue (P < 0.05).

Conclusions

Nal-P-113 exhibited protective effects on Porphyromonas gingivalis-induced periodontitis in rats by limiting the amount of bacteria and modulating IL-1β and TNF-α production. The use of Nal-P-113 in vivo might serve as a beneficial preventive or therapeutic approach for periodontitis.

Electronic supplementary material

The online version of this article (doi:10.1186/s12906-017-1931-9) contains supplementary material, which is available to authorized users.

Identification of the Disrupted Pathways Associated with Periodontitis Based on Human Pathway Network

Objective: The objective of this work is to search for a novel method to explore the disrupted pathways associated with periodontitis (PD) based on the network level.

Methods: Firstly, the differential expression genes (DEGs) between PD patients and cognitively normal subjects were inferred based on LIMMA package. Then, the protein-protein interactions (PPI) in each pathway were explored by Empirical Bayesian (EB) co-expression program. Specifically, we determined the 100th weight value as the threshold value of the disrupted pathways of PPI by constructing the randomly model and confirmed the weight value of each pathway. Meanwhile, we dissected the disrupted pathways under the weight value > the threshold value. Pathways enrichment analyses of DEGs were carried out based on Expression Analysis Systematic Explored (EASE) test. Finally, the better method was selected based on the more rich and significant obtained pathways by comparing the two methods.

Results: After the calculation of LIMMA package, we estimated 524 DEGs in all. Then we determined 0.115222 as the threshold value of the disrupted pathways of PPI. When the weight value>0.115222, there were 258 disrupted pathways of PPI enriched in. Additionally, we observed those 524 DEGs that were enriched in 4 pathways under EASE=0.1.

Conclusion: We proposed a novel network method inferring the disrupted pathway for PD. The disrupted pathways might be underlying biomarkers for treatment associated with PD.

Assessment of MMP-1, MMP-8 and TIMP-2 in experimental periodontitis treated with kaempferol

Purpose

The objective of this study was to investigate the effect of a dietary flavonoid, kaempferol, which has been shown to possess antiallergic, anti-inflammatory, anticarcinogenic, and antioxidant activities on the periodontium by histomorphometric analysis and on gingival tissue matrix metalloproteinase-1 (MMP-1), MMP-8, and tissue inhibitor of metalloproteinase-2 (TIMP-2) by biochemical analysis of rats after experimental periodontitis induction.

Methods

Sixty Wistar rats were randomly divided into six groups of ten rats each, and silk ligatures were placed around the cervical area of the mandibular first molars for 15 days, except in the healthy control rats. In the experimental periodontitis groups, systemic kaempferol (10 mg/kg/2d) and saline were administered by oral gavage at two different periods (with and without the presence of dental biofilm) to all rats except for the ten non-medicated rats. Alveolar bone area, alveolar bone level, and attachment level were determined by histomorphometric analysis, and gingival tissue levels of MMP-1, MMP-8, and TIMP-2 were detected by biochemical analysis.

Results

Significantly greater bone area and significantly less alveolar bone and attachment loss were observed in the kaempferol application groups compared to the control groups (P<0.05). In addition, gingival tissue MMP-1 and -8 levels were significantly lower in the kaempferol application groups compared to the control groups and the periodontitis group (P<0.001). There were no statistically significant differences in TIMP-2 levels between the kaempferol and saline application groups (P>0.05).

Conclusions

Kaempferol application may be useful in decreasing alveolar bone resorption, attachment loss, and MMP-1 and -8 production in experimental periodontitis.

Acanthoic acid inhibits LPS-induced inflammatory response in human gingival fibroblasts

Periodontitis is a chronic disease that affects the gums and destroys connective tissue. Acanthoic acid (AA), a diterpene in Acanthopanax koreanum, has been reported to have anti-inflammatory activities. The aim of this study was to investigate the anti-inflammatory effects of AA on lipopolysaccharide (LPS)-induced inflammatory response in human gingival fibroblasts (HGFs). HGFs were treated with Porphyromonas gingivalis LPS in the presence or absence of AA. The production of inflammatory cytokines IL-8 and IL-6 were measured by ELISA. The expression of NF-κB and TLR4 were detected by Western blotting. The results showed that AA inhibited LPS-induced IL-8 and IL-6 production in a dose-dependent manner. In addition, AA inhibited LPS-induced TLR4 expression and NF-κB activation. In conclusion, AA inhibits LPS-induced inflammatory response in HGFs through inhibition TLR4-mediated NF-κB signaling pathway.

Chronic Periodontitis Is Associated With Spinal Dysmobility in Patients With Ankylosing Spondylitis

BACKGROUND

Although microbes have been suggested to play a role in the pathogenesis of ankylosing spondylitis (AS), several studies present contradictory results regarding the association between AS and chronic periodontitis (CP).

METHODS

Clinical, laboratory, and medication data were collected from 84 patients with AS and 84 age- and sex-matched controls. Periodontal measurements, including probing depths (PDs), clinical attachment loss (AL), serum anti-Porphyromonas gingivalis titers, and the detection of P. gingivalis DNA in gingival crevicular fluid, were recorded. All participants with periodontitis with PD ≥4 to <7 mm received scaling and root planing and were re-evaluated at 12 weeks; those still exhibiting periodontitis with PD of ≥4 to <7 mm at 12 weeks were followed at 24 weeks.

RESULTS

The prevalence of moderate-to-severe CP was not different between patients with AS and controls (70.2% versus 66.6%). The P. gingivalis detection rate was not different between patients with AS and controls or between patients with AS receiving and not receiving anti-tumor necrosis factor (TNF)-α agents. However, CP was positively associated with impaired spinal mobility of patients with AS in multivariate analyses. After periodontal treatment, PD and AL levels were improved in both groups, but the change was significantly greater in patients with AS than in controls. Patients with AS receiving anti-TNF-α agents exhibited a greater improvement in PD and AL than those who did not.

CONCLUSIONS

Although AS was not associated with the presence of CP, CP was associated positively with the severity of spinal dysmobility in Korean patients with AS. These results suggest that periodontitis can have a negative effect on axial movement in AS.

The Influence of Interleukin 17A and IL17F Polymorphisms on Chronic Periodontitis Disease in Brazilian Patients

A case-control study was conducted on patients with chronic periodontitis (CP) and healthy controls with the aim of evaluating possible association between interleukin 17A (IL17A) G197A (rs2275913) and IL17F T7488C (rs763780) polymorphisms and periodontitis. Genotypes were determined by PCR-RFLP method. Statistical analyses were conducted using the OpenEpi and SNPStas software to calculate Chi-square with Yates correction or Fisher's exact tests, odds ratios (OR), and 95% confidence intervals (CIs). SNPStas software was used to calculate Hardy-Weinberg equilibrium. IL17A AA genotype was more frequent in patients with chronic periodontitis (CP) in the codominant and recessive models (P = 0.09; OR = 2.53 and P = 0.03; OR = 2.46, resp.), the females with CP (P = 0.01, OR = 4.34), Caucasoid patients with CP (P = 0.01, OR = 3.45), and nonsmoking Caucasian patients with CP (P = 0.04, OR = 3.51). The IL17A A allele was also more frequent in Caucasians with CP (P = 0.04, OR = 1.59). IL17F T7488C polymorphism was not associated with chronic periodontitis. In these patients from Southern Brazil, the IL17A rs2275913 polymorphisms, IL17A AA genotype, and the A allele were associated with a susceptibility to chronic periodontitis.

Effectiveness of CoQ10 Oral Supplements as an Adjunct to Scaling and Root Planing in Improving Periodontal Health

INTRODUCTION

Deficiency of CoQ 10 was found in human inflamed gingiva and has been found to be responsible for periodontal destruction.

AIM

To evaluate the effectiveness of CoQ 10 supplementation as an adjunct to scaling and rootplaning in reducing gingival inflammation and periodontal pocket depth.

MATERIALS AND METHODS

The study was a randomized, double-blind, controlled, parallel group design clinical trial. Thirty subjects with plaque induced gingival inflammation and having atleast three nonadjacent interproximal sites with a probing pocket depth ≥ 5mm were included in the study. The subjects were randomly divided into two groups. The test group (n=15) in which patients were given oral CoQ10 supplements after scaling and root planing and the control group (n=15) in which patients were given an oral placebo after scaling and rootplaning. The plaque index, gingival index and probing depth were recorded at baseline, 1 month and 3 months. Statistical analysis done by using Student's paired t-test for intragroup comparison and unpaired t-test for inter-group comparison.

RESULTS

Both the groups showed marked reduction of afore mentioned periodontal parameters at one month and three months when compared to baseline. Though there was no significant difference in plaque index and probing pocket depth between the two groups at any given time period, test group showed significant difference in gingival inflammation at one month and three months when compared to control group.

CONCLUSION

In the present study use of Coenzyme Q10 oral supplements as an adjunct to scaling and root planing showed significant reduction in gingival inflammation when compared to scaling and rootplaning alone.

Relationship between diabetes and periodontal infection

Periodontal disease is a high prevalent disease. In the United States 47.2% of adults ≥ 30 years old have been diagnosed with some type of periodontitis. Longitudinal studies have demonstrated a two-way relationship between diabetes and periodontitis, with more severe periodontal tissue destruction in diabetic patients and poorer glycemic control in diabetic subjects with periodontal disease. Periodontal treatment can be successful in diabetic patients. Short term effects of periodontal treatment are similar in diabetic patients and healthy population but, more recurrence of periodontal disease can be expected in no well controlled diabetic individuals. However, effects of periodontitis and its treatment on diabetes metabolic control are not clearly defined and results of the studies remain controversial.

Tormentic acid inhibits LPS-induced inflammatory response in human gingival fibroblasts via inhibition of TLR4-mediated NF-κB and MAPK signalling pathway

OBJECTIVE

Periodontal disease is one of the most prevalent oral diseases, which is associated with inflammation of the tooth-supporting tissues. Tormentic acid (TA), a triterpene isolated from Rosa rugosa, has been reported to exert anti-inflammatory effects. The aim of this study was to investigate the anti-inflammatory effects of TA on lipopolysaccharide (LPS)-stimulated human gingival fibroblasts (HGFs).

METHODS

The levels of inflammatory cytokines such as interleukin (IL)-6 and chemokines such as IL-8 were detected by enzyme-linked immunosorbent assay (ELISA). The expression of Toll-like receptor 4 (TLR4), nuclear factor kappa B (NF-κB), IκBα, p38, extracellular signal-regulated kinase (ERK), and c-Jun N-terminal kinase (JNK) was determined by Western blotting.

RESULTS

The results showed that Porphyromonas gingivalis LPS significantly upregulated the expression of IL-6 and IL-8. TA inhibited the LPS-induced production of IL-6 and IL-8 in a dose-dependent manner. Furthermore, TA inhibited LPS-induced TLR4 expression; NF-κB activation; IκBα degradation; and phosphorylation of ERK, JNK, and P38.

CONCLUSION

TA inhibits the LPS-induced inflammatory response in HGFs by suppressing the TLR4-mediated NF-κB and mitogen-activated protein kinase (MAPK) signalling pathway.

Role of Regulators of G Protein Signaling Proteins in Bone Physiology and Pathophysiology

Regulators of G protein signaling (RGS) proteins enhance the intrinsic GTPase activity of α subunits of the heterotrimeric G protein complex of G protein-coupled receptors (GPCRs) and thereby inactivate signal transduction initiated by GPCRs. The RGS family consists of nearly 37 members with a conserved RGS homology domain which is critical for their GTPase accelerating activity. RGS proteins are expressed in most tissues, including heart, lung, brain, kidney, and bone and play essential roles in many physiological and pathological processes. In skeletal development and bone homeostasis as well as in many bone disorders, RGS proteins control the functions of various GPCRs, including the parathyroid hormone receptor type 1 and calcium-sensing receptor and also regulate various critical signaling pathways, such as Wnt and calcium oscillations. This chapter will discuss the current findings on the roles of RGS proteins in regulating signaling of key GPCRs in skeletal development and bone homeostasis. We also will examine the current updates of RGS proteins' regulation of calcium oscillations in bone physiology and highlight the roles of RGS proteins in selected bone pathological disorders. Despite the recent advances in bone and mineral research, RGS proteins remain understudied in the skeletal system. Further understanding of the roles of RGS proteins in bone should not only provide great insights into the molecular basis of various bone diseases but also generate great therapeutic drug targets for many bone diseases.

Periodontitis as a risk factor of atherosclerosis

Over the last two decades, the amount of evidence corroborating an association between dental plaque bacteria and coronary diseases that develop as a result of atherosclerosis has increased. These findings have brought a new aspect to the etiology of the disease. There are several mechanisms by which dental plaque bacteria may initiate or worsen atherosclerotic processes: activation of innate immunity, bacteremia related to dental treatment, and direct involvement of mediators activated by dental plaque and involvement of cytokines and heat shock proteins from dental plaque bacteria. There are common predisposing factors which influence both periodontitis and atherosclerosis. Both diseases can be initiated in early childhood, although the first symptoms may not appear until adulthood. The formation of lipid stripes has been reported in 10-year-old children and the increased prevalence of obesity in children and adolescents is a risk factor contributing to lipid stripes development. Endothelium damage caused by the formation of lipid stripes in early childhood may lead to bacteria penetrating into blood circulation after oral cavity procedures for children as well as for patients with aggressive and chronic periodontitis.

Effect of telmisartan on levels of IL-1, TNF-α, down-regulated COX-2, MMP-2, MMP-9 and RANKL/RANK in an experimental periodontitis model

AIM

The aim of this study was to evaluate the effect of telmisartan (TELM) on inflammation, oxidation and the expression of matrix metalloproteinases (MMPs) and the expression RANKL/RANK/OPG in the periodontal tissue of a rat model for ligature-induced periodontitis.

MATERIALS AND METHODS

Male Wistar albino rats were randomly divided into five groups of 10 rats each: (i) non-ligated, given water; (ii) ligated, given water; (iii) ligated, given 1 mg/kg TELM; (iv) ligated, given 5 mg/kg TELM; and (v) ligated, given 10 mg/kg TELM. All groups were treated with saline or TELM for 10 days. Periodontal tissue was analysed by histopathology; by the immunohistochemical examination of COX-2, MMP-2, MMP-9 and the RANKL/RANK/OPG pathway; and by ELISA analysis of the levels of IL-1β, IL-10, TNF-α, myeloperoxidase (MPO), malonaldehyde (MDA) and glutathione (GSH).

RESULTS

Treatment with 10 mg/kg TELM resulted in reduced concentrations of MPO, MDA (p < 0.05) and the pro-inflammatory cytokine IL-1β (p < 0.05); reduced expression of MMP-2, MMP-9, RANK, RANKL and COX-2; and an increase in OPG. The levels of TNF-α were significantly reduced in all TELM-treated groups.

CONCLUSIONS

These findings confirm the involvement of TELM in reducing the inflammatory response, oxidative stress and bone loss in ligature-induced periodontitis in rats.

Moutan Cortex Radicis inhibits inflammatory changes of gene expression in lipopolysaccharide-stimulated gingival fibroblasts

Moutan Cortex Radicis (MCR), the root bark of Paeonia suffruticosa Andrews (Paeoniaceae), is found in the traditional Chinese medicinal formulae which were used to treat periodontal diseases. This study investigated the changes in gene expression by MCR treatment when stimulated with lipopolysaccharide (LPS) in cultured human gingival fibroblasts (HGFs). A genome-wide expression GeneChip was used for the gene array analysis, and real-time reverse transcription polymerase chain reaction (RT-PCR) analysis was also performed to confirm the gene expression. It was shown that 42 of the 643 genes up-regulated by LPS, when compared to the control, were down-regulated by the MCR treatment. Of these 42 genes, the inflammation and immune response-related genes were especially noted, which indicates that MCR inhibits the induction of inflammation by LPS stimulation. In addition, 33 of the 519 genes down-regulated by LPS, when compared to the control, were up-regulated by the MCR treatment. The expression patterns of some representative genes by real-time RT-PCR correlated with those of the genes shown in the microarray. In addition, the MCR extract contained paeonol and paeoniflorin, which are known to have the anti-inflammatory effect as the major phenolic components of MCR. This study showed that the MCR extract could comprehensively inhibit a wide variety of activations of inflammation-related genes, which may be due to paeonol and paeoniflorin. It is, thus, suggested that MCR may be applied to alleviate the inflammation of periodontal diseases.

Host modulation by therapeutic agents

Periodontal disease susceptible group present advanced periodontal breakdown even though they achieve a high standard of oral hygiene. Various destructive enzymes and inflammatory mediators are involved in destruction. These are elevated in case of periodontal destruction. Host modulation aims at bringing these enzymes and mediators to normal level. Doxycycline, nonsteroidal anti-inflammatory drugs (NSAIDs), bisphosphonates, nitrous oxide (NO) synthase inhibitors, recombinant human interleukin-11 (rhIL-11), omega-3 fatty acid, mouse anti-human interleukin-6 receptor antibody (MRA), mitogen-activated protein kinase (MAPK) inhibitors, nuclear factor-kappa B (NF-kb) inhibitors, osteoprotegerin, and tumor necrosis factor antagonist (TNF-α) are some of the therapeutic agents that have host modulation properties.

Inter-generational continuity in periodontal health: findings from the Dunedin family history study

OBJECTIVE

To determine whether parental periodontal disease history is a risk factor for periodontal disease in adult offspring.

METHODS

Proband periodontal examination [combined attachment loss (CAL) at age 32, and incidence of CAL from ages 26 to 32] and interview data were collected during the age-32 assessments in the Dunedin Study. Parental data were also collected. The sample was divided into two familial-risk groups for periodontal disease (high- and low-risk) based on parents' self-reported periodontal disease.

RESULTS

Periodontal risk analysis involved 625 proband-parent(s) groups. After controlling for confounding factors, the high-familial-risk periodontal group was more likely to have 1+ sites with 4+mm CAL [relative risk (RR) 1.45; 95% confidence interval (CI) 1.11-1.88], 2+ sites with 4+mm CAL (RR 1.45; 95% CI 1.03-2.05), 1+ sites with 5+mm CAL (RR 1.60; 95% CI 1.02-2.50), and 1+ sites with 3+mm incident CAL (RR 1.64; 95% CI 1.01-2.66) than the low-familial-risk group. Predictive validity was enhanced when information was available from both parents.

CONCLUSIONS

Parents with poor periodontal health tend to have offspring with poor periodontal health. Family/parental history of oral health is a valid representation of the shared genetic and environmental factors that contribute to an individual's periodontal status, and may help to predict patient prognosis and preventive treatment need.

Intergenerational continuity in oral health: a review

Life course research considers not only the influences on health which act during the lifespan but it is also concerned with factors that act across generations. Rarely are genetics or environment solely responsible for producing individual variation; virtually all characteristics are the result of gene-environment interaction. An increasing interest in life course research and gene-environment interactions is reflected in greater awareness of the role of family history and intergenerational continuity in oral health as a practical, inexpensive approach to categorizing genetic risk for many common, preventable disorders of adulthood (including oral disease). Does the health status of one generation have an effect on that of the next? While researchers in recent years have begun to investigate the inter-generational associations between exposures and disease, little research has been carried out (to date) on the long-term biological, behavioural, psychological, social and environmental mechanisms that link oral health and oral disease risk to exposures acting across generations. This narrative review identifies studies which have contributed to highlighting some of the intergenerational factors influencing oral health. However, there is a need for a wider perspective on intergenerational continuity in oral health, along with a careful evaluation of the factors which contribute to the effect. A comprehensive investigation into the nature and extent of intergenerational transmission of oral health is required.

Variants of the human PPARG locus and the susceptibility to chronic periodontitis

Apart from its regulatory function in lipid and glucose metabolism, peroxisome proliferator-activated receptor (PPAR)γ has impact on the regulation of inflammation and bone metabolism. The aim of the study was to investigate the association of five polymorphisms (rs10865710, rs2067819, rs3892175, rs1801282, rs3856806) within the PPARG gene with chronic periodontitis. The study population comprised 402 periodontitis patients and 793 healthy individuals. Genotyping of the PPARG gene polymorphisms was performed by PCR and melting curve analysis. Comparison of frequency distribution of genotypes between individuals with periodontal disease and healthy controls for the polymorphism rs3856806 showed a P-value of 0.04 but failed to reach significance after correction for multiple testing ( P < 0.01). Two single nucleotide polymorphisms (SNPs) (rs10865710 and rs3892175) were found to be in strong linkage disequilibrium to rs2067819 (D’ > 0.90). A 3-site analysis (rs2067819-rs1801282-rs3856860) revealed five haplotypes with a frequency of ≥1% among cases and controls. Following adjustment for age, gender and smoking, none of the haplotypes was significantly different between periodontitis and healthy controls after Bonferroni correction. This study could not show a significant association between PPARG gene variants and chronic periodontitis.

Clinical studies on the management of periodontal diseases utilizing subantimicrobial dose doxycycline (SDD)

Periodontitis, the most common chronic inflammatory condition known to mankind, is a disease that results in the destruction of tooth supporting tissues. Periodontitis is initiated by a bacterial biofilm on the tooth surface below the gingival margin. Until fairly recently it was assumed that the bacteria were the primary cause of tissue destruction, however, a large body of research has revealed that it is the patient's immune response that is actually responsible for the majority of the breakdown of tooth supporting tissues. Contemporary thinking suggests that successful, long term management of chronic periodontitis may combine both local mechanical and antimicrobial strategies to reduce the microbial bio-burden along with modulation of the host, patient's excessive, immuno-inflammatory response to the bacterial exposure known as host modulatory therapy (HMT). Based on extensive literature documenting the enzymatic inhibition and related anti-inflammatory properties of the tetracyclines, a new drug was developed as a host modulatory agent and approved by the United States Food and Drug Administration (FDA) for use as an adjunct to conventional scaling and root planing for the treatment of chronic periodontitis. A subantimicrobial dose of doxycycline (SDD) at 20 mg (Periostat(®)) has been found to be a safe and effective adjunct when taken twice daily for at least 3 months and up to 24 months in randomized placebo controlled clinical trials. Periostat(®) is currently the only FDA approved inhibitor of the matrix metalloproteinases implicated in the plaque-induced pathologic degradation of connective tissue collagen of the periodontal supporting structures. This review paper begins with a brief description of the disease process known as periodontitis followed by an extensive review of the Phase I-IV clinical trial data that established the safety and efficacy of sub-antimicrobial dose doxycycline (SDD) as an adjunct to scaling and root planing for the treatment of periodontitis.

Blood cell gene expression profiling in subjects with aggressive periodontitis and chronic arthritis

BACKGROUND

Microarray analysis of local and peripheral cells in subjects with immune-inflammatory diseases may identify candidate genes associated with these diseases. The present study identified differentially expressed genes in peripheral blood mononuclear cells (PBMCs) from subjects with untreated localized aggressive periodontitis (LAgP) or generalized aggressive periodontitis (GAgP). Differentially expressed genes were validated in groups of subjects with LAgP, GAgP, juvenile idiopathic arthritis (JIA), or rheumatoid arthritis (RA) and controls.

METHODS

Candidate genes were identified by gene expression profiling of PBMCs using a microarray system in untreated gender-matched subjects with LAgP (N = 2) or GAgP (N = 3) and controls (N = 2) younger than 35 years of age. The microarray results were validated by real-time reverse transcription-polymerase chain reaction (RT-PCR) using PBMCs from 103 individuals, including groups of subjects with LAgP (N = 18), GAgP (N = 27), JIA (N = 10), or RA (N = 23) and controls (N = 25).

RESULTS

Of 53 differentially expressed candidate genes identified in subjects with LAgP, 14 were involved in immune responses and inflammatory processes. Of these, the RT-PCR validation confirmed that Toll-like receptor 2 gene (TLR2) and myomesin 2 gene had a significantly higher expression in subjects with LAgP than in controls. RT-PCR also showed increased expression of TLR2 in subjects with RA. Comparison of subjects with GAgP to controls using microarray analysis identified only three upregulated genes.

CONCLUSION

Several genes upregulated in subjects with LAgP were related to immune responses including TLR2 and myomesin 2.

Interleukin- 1 gene polymorphisms as assessed in a 10-year study of patients with early-onset periodontitis

Our 10-year study of early-onset periodontitis (EOP) patients includes repeated clinical observations, microbiological characteristics and analysis of genetic polymorphism of IL-1A and IL-1B genes. Twenty patients (age 15-26 years) were divided according to the clinical status in the 4th year into a group with mean number of teeth with bleeding on probing (BP) 9.8 and mean number of teeth with periodontal pocket (PP) 2.23, and a group with mean number of teeth with BP 5.37 and no PP. Significantly higher values of mean BP and PP were found among the groups during the study but a strong progression of disease was found only in 3 patients. The risk IL-1A allele-2 and IL-1B allele-2 genotype and bacterial presence were analyzed by DNA hybridization methods. No significant differences of bacteria composition (Treponema denticola, Porphyromonas gingivalis, Actinobacillus actinomycetemcomitans) were found between the groups. A higher prevalence of composite IL-1 genotype was detected in the group of EOP patients with progressive disease. Early finding of the disease followed by conservative therapy could positively influence the disease progression. EOP treated in early stages may, but need not, develop into the aggressive form in the presence of risk genotype IL-1.

Prevalence of the -295 T-to-C promoter polymorphism of the interleukin (IL)-16 gene in periodontitis

Interleukin (IL)-16 is involved in the regulation of the expression of several proinflammatory cytokines, i.e. tumour necrosis factor (TNF)alpha and interleukin (IL)-1beta. The present study aimed to determine the prevalence of the -295 promoter polymorphism of the interleukin (IL)-16 gene in periodontal disease. A total of 123 patients with periodontal disease and 122 healthy controls were genotyped for the -295 IL-16 promoter polymorphism. Genotyping has been performed by PCR and restriction fragment length polymorphism (RFLP) analysis. The frequencies of alleles and genotypes as well of haplotypes within both study groups were compared using the Pearson chi(2) test at a level of significance of 5% (P < 0.05). The distribution of genotypes for the -295 IL-16 gene polymorphism showed no significant difference between periodontitis patients and healthy control subjects (P = 0.886). Also stratification analysis according to the disease severity revealed no significant difference regarding the genotype distribution among both study groups. Herein the IL-16 -295 gene polymorphism was not associated with chronic periodontitis.

Lipid peroxidation: a possible role in the induction and progression of chronic periodontitis

OBJECTIVES

Reactive oxygen species (ROS) are implicated in the destruction of the periodontium during inflammatory periodontal diseases. The imbalance in oxidant/antioxidant activity may be a key factor in the damaging effects of ROS. This study aimed to determine the lipid peroxidation levels in gingival crevicular fluid and saliva, and glutathione (GSH) and glutathione peroxidase (GPx) in saliva in patients with chronic periodontitis.

METHODS

Gingival crevicular fluid and saliva were collected from 13 patients and 9 healthy control subjects during the preliminary study, and from 21 patients during the subsequent study. Lipid peroxidation level, GSH level and GPx activity were determined by spectrophotometric assay.

RESULTS

The preliminary study found that when comparing patients to healthy controls, the gingival crevicular fluid samples produced the following results, respectively: higher lipid peroxidation concentration (microm) (by sites: 167.55 vs. 53.71, p < 0.0001; by subjects: 151.99 vs. 50.66, p < 0.005) and total amount (pmol) (by sites: 93.02 vs. 8.47, p < 0.0001, by subjects: 80.44 vs. 7.84, p < 0.0005). In saliva samples, lower GSH concentration (microm) (373.04 vs. 606.67, p < 0.05), higher lipid peroxidation concentration (microm) (0.66 vs. 0.13, p < 0.0005), and no difference in GPx activity were found in patients than in those of healthy controls. The subsequent study showed statistically significant (p < 0.05) improvement of clinical periodontal parameters (plaque index, gingival index, probing attachment level, probing pocket depth and gingival crevicular fluid volume), decreases in gingival crevicular fluid lipid peroxidation levels (concentration and total amount) at the sites after the completion of phase 1 periodontal treatment. Similarly, the periodontal treatment resulted in a significant decrease of lipid peroxidation concentrations (p < 0.05), increase in GSH concentration (p < 0.001), and no change in GPx activity in saliva samples.

CONCLUSION

The increased levels of lipid peroxidation may play a role in the inflammation and destruction of the periodontium in periodontitis.

Identification of genetic risk factors for periodontitis and possible mechanisms of action

AIM

To review the literature for genetic risk factors associated with periodontitis.

METHODS

Computerized search of the literature in English using key words: Periodontitis; Genes; Mutation; Polymorphism; Risk.

RESULTS AND CONCLUSIONS

Mutations in the cathepsin C gene (CTSC) have been identified as causal for the Papillon-Lefèvre syndrome (PLS), which includes prepubertal periodontitis (PP). Some CTSC mutations are causal for PP without PLS. No relationship has been demonstrated between CTSC mutations and other forms of periodontitis. Genetic polymorphisms in a candidate gene approach have been explored as risk factors for periodontitis. There is limited evidence that some polymorphisms in the genes encoding interleukins (IL)-1, Fc gamma receptors (Fc gammaR), IL-10 and the vitamin D receptor, may be associated with periodontitis in certain ethnic groups. However relatively large variations in carriage rates of the Rare (R)-alleles among studies on any polymorphism were observed. The available studies appear under-powered and do not adequately take into account other pertinent risk factors for periodontitis. Future studies should include larger cohorts, should clearly define phenotypes and should adequately control for other risk factors. In addition to the candidate gene approach, alternative strategies need to be considered to elucidate the gene variations, which confer risk for periodontitis.

Etiology and pathogenesis of periodontal diseases

The two most prevalent and most investigated periodontal diseases are dental plaque-induced gingivitis and chronic periodontitis. The last 10 to 15 years have seen the emergence of several important new findings and concepts regarding the etiopathogenesis of periodontal diseases. These findings include the recognition of dental bacterial plaque as a biofilm, identification and characterization of genetic defects that predispose individuals to periodontitis, host-defense mechanisms implicated in periodontal tissue destruction, and the interaction of risk factors with host defenses and bacterial plaque. This article reviews current aspects of the etiology and pathogenesis of periodontal diseases.

Polymorphisms of the interleukin-18 gene in periodontitis patients

BACKGROUND

Interleukin (IL)-18 regulates the expression of the proinflammatory cytokine interferon (IFN)-gamma. The present study sought to test the putative involvement of six different IL-18 gene polymorphisms in pre-disposition to destructive periodontal disease.

METHODS

A total of 123 patients with periodontitis and 121 healthy controls were genotyped for six IL-18 polymorphisms at position -656, -607, -137, +113, +127 and codon 35/3. Genotyping has been performed by PCR and restriction fragment length polymorphism analysis. The frequencies of alleles and genotypes as well of haplotypes within both study groups were compared using the Pearson Chi-square test at a level of significance of 5% (p<0.05).

RESULTS

Coseggregation was found to be 100% for the two polymorphisms at position -656 and -607 as well as for the polymorphisms at position -137, +113, and +127. The distribution of genotypes for the IL-18 gene polymorphism at position -656/-607 (p=0.854), at position -137/+113/+127 (p=0.320), and at codon 35/3 (p=0.481) was not significantly different among periodontitis patients if compared with healthy control subjects. The distribution of haplotype combinations for the -607 and -137 polymorphism also showed not significant difference between the both study groups (p=0.545).

CONCLUSION

Herein the six different IL-18 gene polymorphisms were not associated with destructive periodontal disease.

The CD14 -159C-to-T promoter polymorphism in periodontal disease

BACKGROUND

A single-nucleotide promoter polymorphism in the CD14 gene was associated with various inflammatory conditions. The present study sought to determine the frequency of the CD14 -159C-to-T polymorphism among subjects with periodontitis and healthy control individuals.

METHODS

A total of 70 patients with periodontal disease and 75 healthy controls were genotyped for the CD14 -159C-to-T polymorphism. Genotyping was performed by polymerase chain reaction and restriction fragment length polymorphism analysis. The allele frequencies and distribution of genotypes within both study groups were compared using Fisher's exact test at a level of significance of 5% (p<0.05).

RESULTS

Overall, the frequency for the CD14 -159T allele in patients with periodontitis was 39.3% (55/140) and 48.0% (72/150) for the controls (p=0.135). The CD14 -159C allele was significantly more prevalent (p=0.013) among females with periodontitis (33.3%; 24/72) as compared with healthy control subjects (55.6%; 30/54). In contrast, the distribution of the CD14 -159C-to-T polymorphism showed no significant difference among males with and without periodontitis (p=0.816).

CONCLUSION

Herein, the C -159T promoter polymorphism of the CD14 gene was associated in female but not in male patients with periodontal disease.

Socioeconomic inequalities in oral health in childhood and adulthood in a birth cohort

OBJECTIVES

To determine whether adult oral health is predicted by (a) childhood socioeconomic advantage or disadvantage (controlling for childhood oral health), or (b) oral health in childhood (controlling for childhood socioeconomic advantage or disadvantage), and whether oral health in adulthood is affected by changes in socioeconomic status (SES).

METHODS

Participants in a longstanding cohort study underwent systematic dental examination for dental caries and tooth loss at ages 5 and 26 years. The examination at age 26 years included the collection of data on periodontal attachment loss and plaque level. Childhood SES was determined using parental occupation, and adult SES was determined from each study member's occupation at age 26 years. Regression models were used to test the study hypotheses.

RESULTS

Complete data were available for 789 individuals (47.4% female). After controlling for childhood oral health, those who were of low SES at age 5 years had substantially greater mean DFS and DS scores by age 26 years, were more likely to have lost a tooth in adulthood because of caries, and had greater prevalence and extent of periodontitis. A largely similar pattern was observed (after controlling for childhood SES) among those with greater caries experience at age 5 years. For almost all oral health indicators examined, a clear gradient was observed of greater disease at age 26 years across socioeconomic trajectory groups, in the following order of ascending disease severity and prevalence: 'high-high', 'low-high' (upwardly mobile), 'high-low' (downwardly mobile) and 'low-low'.

CONCLUSION

Adult oral health is predicted by not only childhood socioeconomic advantage or disadvantage, but also by oral health in childhood. Changes in socioeconomic advantage or disadvantage are associated with differing levels of oral health in adulthood. The life-course approach appears to be a useful paradigm for understanding oral health disparities.

Lack of association between the TNFalpha G -308 A promoter polymorphism and periodontal disease

BACKGROUND

Immunorelevant gene polymorphisms might influence the susceptibility for periodontal disease. The present study assessed the frequency of a promoter polymorphism (-308G-to-A) of the tumour necrosis factor (TNF)alpha gene in patients with periodontitis and controls.

METHODS

Eighty-one patients with generalized chronic periodontitis and 80 healthy controls were genotyped for the -308 polymorphism of the TNF alpha gene by PCR amplification and subsequent restriction fragment length polymorphism analysis. The diagnosis of chronic periodontitis was made for each subject on basis of standardized clinical and radiographic criteria.

RESULTS

In patients with peridontitis and controls, the frequency of the TNF alpha-308 A allele was comparable (19.1% [31/162] versus 13.8% [22/160]; p=0.193).

CONCLUSION

The present study revealed no association between the -308 TNF alpha gene polymorphism and periodontal disease.

Modulation of clinical expression of plaque-induced gingivitis. III. Response of "high responders" and "low responders" to therapy

AIM

The aim of the present study was to characterize the subject-based clinical behavior of the gingiva in response to a tooth-cleaning regimen in two subpopulations, "high-responder" (HR) and "low-responder" (LR) groups, presenting a different inflammatory response to plaque accumulation.

MATERIAL AND METHODS

The study population comprised of 96 systemically and periodontally healthy subjects, 46 males and 50 females, non-smokers, enrolled in an experimental gingivitis trial. At completion of the experimental gingivitis period (day 21), all subjects were prescribed the same 21-day treatment regimen of amine/stannous fluoride (AmF/SnF(2))-containing toothpaste and mouthrinse. Plaque index (PlI), gingival index (GI), gingival crevicular fluid volume (GCF), and angulated bleeding score (AngBS) were recorded on three selected teeth. Treatment efficacy was evaluated in the overall population as well as in HR and LR groups, separately.

RESULTS

A statistically significant decrease of PlI was observed after treatment (p<0.001), with PlI reversing to baseline levels. Changes in PlI revealed the same trend in both HR and LR groups, without differences between groups. Treatment also resulted in a significant decrease of all gingivitis parameters (p<0.001 for all comparisons). After treatment, GI, AngBS, and GCF were comparable with baseline condition. However, when the two groups were compared, day 42-GCF was significantly higher in the HR group than the LR group.

CONCLUSIONS

A treatment regimen based on mechanical plaque control supplemented with AmF/SnF(2)-containing toothpaste and mouthrinse is effective in reducing plaque accumulation and re-establishing healthy gingival conditions after experimentally induced gingivitis, even in subjects with different inflammatory response to plaque accumulation.

Modulation of clinical expression of plaque-induced gingivitis. I. Background review and rationale

OBJECTIVES

The purpose of this article is to provide the necessary background and rationale for the accompanying studies, which are ultimately aimed at identifying genetic and environmental factors determining gingivitis susceptibility.

MATERIALS AND METHODS

The literature on factors reported to modify the clinical expression of gingivitis, i.e., factors that determine individual variability in gingival inflammatory response to plaque, is presented.

RESULTS

Clinical evidence suggests that the gingival inflammatory response to plaque accumulation may differ substantially among individuals. However, most of the available studies are of small scale and not purposely designed to address the issue. Systemic factors implicated in modulation of the clinical expression of gingivitis include metabolic, genetic, environmental and other factors. The significance of such factors in designing and conducting a large-scale experimental gingivitis trial and means to account for them are discussed.

CONCLUSION

Although several factors have been implicated, genetic or environmental factors underlying differences in gingivitis expression are not fully elucidated. The accompanying studies aim to identify and characterize, among participants in a specifically designed large-scale experimental gingivitis trial, subjects that differ significantly in their gingival inflammatory response to plaque. This is the first step in an effort to determine genetic or environmental factors underlying such differences.

Toll-like receptor (TLR) 2 and 4 mutations in periodontal disease

Toll-like receptors (TLR) are signal molecules essential for the cellular response to bacterial cell wall components. Different functional effective polymorphisms for the TLR 4 gene (Asp299Gly; Thr399Ile) and for the TLR 2 gene (Arg677Trp, Arg753Gln) have recently been described that are associated with impaired lipopolysaccharide signal transduction. A total of 122 patients with chronic periodontal disease and 122 healthy unrelated controls were genotyped for the Asp299Gly and Thr399Ile polymorphism of the TLR 4 gene and the Arg677Trp and Arg753Gln mutation of the TLR 2 gene. The mutations were identified with polymerase chain reaction followed by restriction fragment length polymorphism (RFLP) analysis. The prevalence of the Asp299Gly and the Thr399Ile mutant allele was 4.1% (10/244) and 4.5% (11/244) among periodontitis patients. For the healthy controls the prevalence was 3.3% (8/244) for the Asp299Gly (P = 0.810) and 3.7% (9/244) for the Thr399Ile mutant allele (P = 0.819). The Arg753Gln mutant allele was found in 2.9% (7/244) of the periodontitis subjects as compared to 4.1% (10/244) in the control group (P = 0.622). The Arg677Trp mutant allele was not found in any of the study subjects. Unlike in ulcerative colitis there was not observed an association between chronic periodontitis and the various mutations of the TLR 2 and 4 gene.

Prevalence of the chemokine receptor CCR5-Δ32 gene mutation in periodontal disease

A 32-base-pair deletion in the CCR5 gene was previously shown to influence the susceptibility for several infectious diseases. The present study compared the frequency of the CCR5-Delta32 mutation among subjects with periodontal disease and healthy control individuals. The prevalence of the CCR5-Delta32 mutation was determined in 81 patients with generalized periodontitis and 121 healthy controls. Standardized clinical and radiographic criteria were used for the diagnosis of periodontitis for each subject. The CCR5-Delta32 mutation was identified by PCR amplification and subsequent agarose gel electrophoresis. Genotype and allele frequencies among both study groups were compared using Fisher's exact test at a level of significance of 5% (P<0.05). The frequency of the CCR5-Delta32 allele was 9.9% (16/162) for periodontitis patients and 10.7% (26/216) for the healthy controls. The allele frequencies between periodontitis patients and the control group for the CCR5-Delta32 mutation were not significantly different (P=0.801). The present study revealed no association between the CCR5-Delta32 mutation and susceptibility to periodontal disease.

Periodontitis is associated with a low concentration of vitamin C in plasma

This study aimed to clarify how concentrations of vitamin C in plasma relate to the serology of periodontitis. The random sample used comprised 431 men, 194 from Finland and 237 from Russia. The plasma vitamin C concentration was determined by o-phtaldialdehyde-fluorometry, and serum immunoglobulin G antibodies to Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis were determined by a multiserotype enzyme-linked immunosorbent assay (ELISA). The mean plasma vitamin C concentration was higher (P < 0.001) in Finnish subjects (mean +/- standard deviation, 4.5 +/- 2.8 mg/liter) than in Russian subjects (1.4 +/- 1.8 mg/liter). Mean antibody levels to both A. actinomycetemcomitans (4.7 +/- 3.6 versus 5.2 +/- 3.1 ELISA units [P = 0.05]) and P. gingivalis (5.7 +/- 2.5 versus 7.6 +/- 2.9 ELISA units [P < 0.001]) were lower in Finnish men than in Russian men. In the combined Finnish and Russian population, the antibody levels to P. gingivalis were negatively correlated with vitamin C concentrations (r = -0.22; P < 0.001); this association remained statistically significant (P = 0.010) in a linear regression model after adjustment for confounding factors. The proportion of P. gingivalis-seropositive subjects decreased with increasing vitamin C concentrations (P for trend, <0.01), but no trend was seen among A. actinomycetemcomitans-seropositive subjects. In conclusion, P. gingivalis infection is associated with low concentrations of vitamin C in plasma, which may increase colonization of P. gingivalis or disturb the healing of the infected periodontium.

Ultrastructure of the gingiva in cardiac patients treated with or without calcium channel blockers

OBJECTIVES

In the last few years, several studies have suggested that periodontal diseases are related to the development of atherosclerosis and its complications. Our objective was to study the ultrastructural morphology of the gingiva from cardiac patients, some of whom were treated and some not with calcium channel blockers compared to a control group.

MATERIAL AND METHODS

Fifty-five patients were studied and grouped in the following way: (a) healthy group (HG) (n=12) healthy patients with at least two pockets between 3 and 5 mm; (b) cardiac group (CG) (n=12) patients with cardiac disease untreated with calcium channel blockers; (c) diltiazem group (DG) (n=13) cardiac patients treated with diltiazem; (d) nifedipine group (NG) (n=18) cardiac patients treated with nifedipine.

RESULTS

Ultrastructural studies in the CG showed inflammatory cells, collagen fibers disruption and a more extended morphologically compromised fibroblast mitochondria. Morphometric studies in CG showed mitochondria that were impaired in number but increased in volume, suggesting metabolic cell suffering. In DG and NG, morphometric data were similar to HG. The presence of myofibroblasts and collagen neosynthesis was detected in DG and NG.

CONCLUSIONS

Our data showed differences in the ultrastructure of the gingival fibroblasts between the studied groups; the DG and NG showed features that could be interpreted as an attempt to restore the cellular metabolic function.

Potential role of vascular endothelial growth factor, interleukin-8 and monocyte chemoattractant protein-1 in periodontal diseases

Host-mediated immunoinflammatory pathways activated by bacteria lead to destruction of the periodontal connective tissues and alveolar bone. The objective of this study was to elucidate the activation of the inflammatory processes in periodontal disease by quantitative assessment of cytokines and periodontopathogens. Gingival crevicular fluids (GCF) and subgingival plaque samples were collected from patients with chronic periodontitis and gingivitis and from periodontally healthy sites. Vascular endothelial growth factor (VEGF), monocyte chemoattractant protein-1 (MCP-1), and interleukin 8 (IL-8) in GCF were analyzed by enzyme-linked immunosorbent assay. Periodontopathogens, including Bacteroides forsythus, Campylobacter rectus, Porphyromonas gingivalis and Prevotella intermedia, were analyzed by immunofluorescence and dark-field microscopy. There was significantly more VEGF and IL-8 in chronic periodontitis and gingivitis sites than in periodontally healthy sites. There were significant positive correlations between the concentrations and total amounts of VEGF and IL-8 in chronic periodontitis and gingivitis sites, and between the levels of periodontopathogens and the total amounts of VEGF, MCP-1 and IL-8. These data indicate that inflammatory processes induced by periodontopathogens and the activation of certain cytokines (VEGF, MCP-1, IL-8) in periodontal diseases may be relevant to host-mediated destruction in chronic periodontitis.

N-acetyl-D-galactosamine specific lectin of Eikenella corrodens induces intercellular adhesion molecule-1 (ICAM-1) production by human oral epithelial cells

During the acute inflammatory response in periodontitis, gingival epithelial cells are considered to play important roles in the recruitment of inflammatory cells to the site of infection through the secretion of chemokines. However, little is known about the expression of molecules that are involved in the interaction between the epithelium and neutrophils following bacterial attachment. Earlier work reported that periodontopathogenic Eikenella corrodens strain 1,073 up-regulated the expression and secretion of chemokines such as interleukin-8 (IL-8) from KB cells (a human oral epithelial cell line derived from a human oral epidermoid carcinoma). To elucidate the mechanism of the transmigration of neutrophils through the epithelium, the present study investigated the expression of adhesion molecules on KB cells in response to E. corrodens attachment. Adhesion molecule gene expression was assessed by RT-PCR and adhesion proteins expressed on KB cell surfaces were determined by cell-based ELISA and FACS. In RT-PCR, ICAM-1 mRNA levels were significantly increased within 1 h in response to exposure to E. corrodens and continued to increase over the 12-h period of study. In ELISA, increased surface ICAM-1 expression was paralleled by increased ICAM-1 mRNA levels. Furthermore, the increases in ICAM-1 expression on epithelial cells infected with E. corrodens were observed to be due to the N-acetyl-D-galactosamine (GalNAc) specific bacterial lectin-like substance of E. corrodens (EcLS), which was one of the adhesins of E. corrodens. This is the first study to report that a bacterial lectin-like substance increased the expression of ICAM-1 on gingival epithelial cells.