RvE1 protects from local inflammation and osteoclast- mediated bone destruction in periodontitis

Periodontitis is a well-appreciated example of leukocyte-mediated bone loss and inflammation that has pathogenic features similar to those observed in other inflammatory diseases such as arthritis. Resolvins are a new family of bioactive products of omega-3 fatty acid transformation circuits initiated by aspirin treatment that counter proinflammatory signals. Because it is now increasingly apparent that local inflammation plays a critical role in many diseases, including cardiovascular disease, atherosclerosis, and asthma, experiments were undertaken to evaluate the actions of the newly described EPA-derived Resolvin E1 (RvE1) in regulation of neutrophil tissue destruction and resolution of inflammation. The actions of an aspirin-triggered lipoxin (LX) analog and RvE1 in a human disease, localized aggressive periodontitis (LAP), were determined. Results indicate that neutrophils from LAP are refractory to anti-inflammatory molecules of the LX series, whereas LAP neutrophils respond to RvE1. In addition, RvE1 specifically binds to human neutrophils at a site that is functionally distinct from the LX receptor. Consistent with these potent actions, topical application of RvE1 in rabbit periodontitis conferred dramatic protection against inflammation induced tissue and bone loss associated with periodontitis.

Effect of neutrophil apoptosis on monocytic cytokine response to Porphyromonas gingivalis lipopolysaccharide

BACKGROUND

Neutrophil apoptosis may play a critical role in the resolution of inflammation by stimulating anti-inflammatory cytokine generation from monocytes. In this study, we investigated the effect of apoptotic neutrophils on interleukin (IL)-10 and IL-1beta production from monocytes in response to Porphyromonas gingivalis lipopolysaccharide.

METHODS

Peripheral blood neutrophils from healthy individuals were isolated by sodium diatrizoate density gradient centrifugation. In order to induce apoptosis, neutrophils were cultured for 24 hours in modified Dulbecco's medium supplemented with 10% autologous serum. Cell apoptosis was quantified by Annexin V positivity and loss of CD16 expression on the cell surface. Peripheral blood mononuclear cells were isolated from the same subjects; monocytes were purified by magnetic cell sorting and cultured with or without apoptotic or fresh neutrophils. Lipopolysaccharide from Porphyromonas gingivalis was used for cell stimulation. IL-1beta and IL-10 levels in supernatants were determined by enzyme-linked immunosorbent assay (ELISA).

RESULTS

IL-10 generation was significantly increased in monocytes cultured with apoptotic neutrophils compared to monocytes alone or cocultured with fresh neutrophils (P <0.05). IL-1beta was suppressed both in resting and lipopolysaccharide-stimulated monocytes in the presence of apoptotic neutrophils compared to monocytes alone or monocytes cultured with fresh neutrophils at all time points (P <0.05).

CONCLUSION

Neutrophil apoptosis provides a signal to monocytes, changing the phenotype of the monocyte resulting in the production of anti-inflammatory cytokines and suppression of proinflammatory cytokines in response to lipopolysaccharide.

Enhanced superoxide release and elevated protein kinase C activity in neutrophils from diabetic patients: association with periodontitis

Inflammation and oxidative stress are important factors in the pathogenesis of diabetes and contribute to the pathogenesis of diabetic complications. Periodontitis is an inflammatory disease that is characterized by increased oxidative stress, and the risk for periodontitis is increased significantly in diabetic subjects. In this study, we examined the superoxide (O(2)(-))-generating reduced nicotinamide adenine dinucleotide phosphate-oxidase complex and protein kinase C (PKC) activity in neutrophils. Fifty diabetic patients were grouped according to glycemic control and the severity of periodontitis. Neutrophils from diabetic patients with moderate [amount of glycated hemoglobin (HbA(1c)) between 7.0% and 8.0%] or poor (HbA(1c) >8.0%) glycemic control released significantly more O(2)(-) than neutrophils from diabetic patients with good glycemic control (HbA(1c) <7.0%) and neutrophils from nondiabetic, healthy individuals upon stimulation with 4beta-phorbol 12-myristate 13-acetate or N-formyl-Met-Leu-Phe. Depending on glycemic status, neutrophils from these patients also exhibited increased activity of the soluble- and membrane-bound forms of PKC, elevated amounts of diglyceride, and enhanced phosphorylation of p47-phox during cell stimulation. In addition, we report a significant correlation between glycemic control (HbA(1c) levels) and the severity of periodontitis in diabetic patients, suggesting that enhanced oxidative stress and increased inflammation exacerbate both diseases. Thus, hyperglycemia can lead to a novel form of neutrophil priming, where elevated PKC activity results in increased phosphorylation of p47-phox and O(2)(-) release.

Simultaneous measurements of cytoplasmic Ca2+ responses and intracellular pH in neutrophils of localized aggressive periodontitis (LAP) patients

In view of the reports that polymorphonuclear leukocytes (PMN) of patients with localized aggressive periodontitis (LAP) exhibit hyper-responsiveness to stimulation, it has been suggested that such abnormalities could lead to PMN-mediated tissue damage during inflammation. To determine whether these abnormalities include signal transduction, we compared cytoplasmic calcium concentration (Delta[Ca2+](i)) and cytoplasmic pH (DeltapH(i)) changes, early stimulus responses to chemotactic agents, of LAP versus control (C)-PMN and explored whether these could be modulated by sensitizing cytokines or calcium channel-blocking agents. PMN responses of LAP patients were compared with age- and gender-matched controls. Delta[Ca2+](i) and DeltapH(i) were measured fluorimetrically using 1H-indole-6-carboxylic acid, 2-[4-[bis[2-[(acetyloxy)methoxy]-2-oxoethyl]amino]-3-[2-[2-[bis[2-[(acetyloxy)methoxy]-2-oxoethyl]amino]-5-methylphenoxy]ethoxy]phenyl]-1 and 2',7'-bis-(carboxyethyl)-5(6)-carboxyfluorescein as respective probes. Not only was the maximal calcium response to chemoattractants higher in LAP-PMN, but also their subsequent intracellular calcium redistribution was significantly slower. The slower calcium redistribution of LAP-PMN, but not their higher maximal calcium response, was successfully mimicked in C-PMN treated with Nifedipine or 1-[b-[3-(4-methoxyphenyl)propoxy]-4-methoxyphenethyl]-1H-imidazole-HCl, both known to be inhibitors of membrane-associated calcium influx, but this redistribution was not affected when inhibitors of other calcium influx mechanisms, Diltiazem or Verapamil, were used. Taken together, our findings indicate that certain early stimulus responses are aberrant in LAP-PMN, that internal redistribution of cytoplasmic-free calcium is compromised, and, additionally, that a membrane-associated Ca2+ transport defect may be present.

Subgingival microbiota of chronic periodontitis subjects from different geographic locations

BACKGROUND

Most clinical studies assume that the subgingival microbiota is similar from one geographic location to another. The purpose of the present investigation was to examine the composition of the subgingival microbiota in chronic periodontitis subjects from four countries.

METHOD

Subjects with chronic periodontitis (N, Sweden=101; USA=115; Brazil=58; Chile=26) were recruited. Subjects were measured at baseline for plaque, gingivitis, bleeding on probing (BOP), suppuration, pocket depth (PD) and attachment level (AL) at six sites per tooth. Subgingival plaque samples taken from the mesial aspect of each tooth at baseline were individually analyzed for their content of 40 bacterial species using checkerboard DNA-DNA hybridization (total samples=6036). % DNA probe counts comprised by each species was determined for each site and averaged across sites in each subject. Significance of differences in proportions of each species among countries was determined using ancova adjusting for age, mean pocket depth, gender and smoking status. p-Values were adjusted for multiple comparisons.

RESULTS

On average, all species were detected in samples from subjects in the four countries. Thirteen species differed significantly in adjusted mean proportions among countries even after adjusting for multiple comparisons. Porphyromonas gingivalis, one species that differed in proportions among countries, comprised adjusted means of 7.5, 11.9, 1.6 and 6.6% of the microbiota in subjects from Brazil, Chile, Sweden and USA (p<0.001), while mean proportions of Treponema denticola were 6.7, 4.2, 0.8 and 2.3, respectively (p<0.001). In contrast, a key periodontal pathogen, Tannerella forsythensis, exhibited mean proportions ranging from 6.2-8.5% and did not differ significantly among countries. Besides these species, prominent species in Brazil were Actinomyces naeslundii genospecies 1 and 2 (8.4%, 7.2%) and Prevotella intermedia (6.5%); in Chile, Prevotella melaninogenica (6.4%) and Neisseria mucosa (5.3%); in Sweden A. naeslundii genospecies 2 (8.4%), Capnocytophaga gingivalis (7.1%) and Peptostreptococcus micros (5.0%); in USA A. naeslundii genospecies 2 (7.5%), P. intermedia (6.8%) and C. gingivalis (6.1%).

CONCLUSIONS

The microbial profiles of subgingival plaque samples from chronic periodontitis subjects in four countries showed surprisingly marked differences. These differences persisted after adjusting for age, mean pocket depth, gender and smoking status.

Hereditary gingival fibromatosis associated with generalized aggressive periodontitis: a case report

BACKGROUND

Hereditary gingival fibromatosis is a rare, genetically inherited overgrowth condition that is clinically characterized by a benign fibrous enlargement of maxillary and mandibular keratinized gingiva. A syndromic association between gingival fibromatosis and a wide variety of other genetically inherited disorders has been described. However, its coexistence with aggressive periodontitis has not been reported.

METHODS

A 24-year-old African-American female, patient (proband X, [Px]) reported with a chief complaint of tooth mobility and gingival enlargement. Clinical examination revealed moderate to severe gingival overgrowth on both mandible and maxilla. Generalized attachment loss and mobility of the teeth were observed. Radiographic evaluation demonstrated severe alveolar bone loss. The patient was diagnosed with gingival fibromatosis and aggressive periodontitis based on the clinical and radiographic findings. Her brother (Bx) and her mother (Mx) were evaluated and diagnosed with gingival fibromatosis suggesting that this is a dominant trait in the family and gingival fibromatosis might be of hereditary origin. In addition, the brother also exhibited localized aggressive periodontitis. Medical history revealed no other systemic or local contributory factors associated with the oral findings in any of the subjects.

RESULTS

Surgical therapy included internal bevel gingivectomy combined with open flap debridement procedures for Px and Bx. Only internal bevel gingivectomy was performed for Mx since there was mild bone resorption and no intrabony defects. At the time of surgery, gingival biopsies were obtained and fixed in 4% paraformaldehyde. Multiple serial sections were stained with hematoxylin and eosin. Microscopic evaluation of the gingival specimens revealed large parallel collagen bundles associated with scarce fibroblasts in the connective tissue. The collagen bundles reached into the subepithelial connective tissue where elongated rete-pegs were also observed. Following the completion of the treatment, no signs of recurrence or bone resorption were observed over 2-year follow-up.

CONCLUSIONS

This is the first report of hereditary gingival fibromatosis associated with aggressive periodontitis. Combined treatment comprising removal of fibrotic gingival tissue and traditional flap surgery for the elimination of intrabony defects represents a unique treatment approach in periodontal therapy. Two-year follow-up revealed that both the gingival overgrowth and the destructive lesions were successfully treated.

A molecular defect in intracellular lipid signaling in human neutrophils in localized aggressive periodontal tissue damage

Host defense mechanisms are impaired in patients with congenital neutrophil (polymorphonuclear neutrophils (PMN)) defects. Impaired PMN chemotaxis is observed in localized aggressive periodontitis (LAP), a familial disorder characterized by destruction of the supporting structures of dentition. In the present studies, we sought evidence for molecular events underlying this aberrant human PMN phenotype. To this end, PMN transendothelial migration and superoxide anion generation were assessed with LAP patients and asymptomatic family members, as well as patients with other chronic mucosal inflammation. PMN from LAP patients showed decreased transmigration across vascular endothelial monolayers (18 +/- 12% of control, n = 4) and increased superoxide anion generation (358 +/- 37%, p = 0.003). Gene expression was analyzed using oligonucleotide microarrays and fluorescence-based kinetic PCR. cDNA microarray and kinetic-PCR analysis revealed diminished RNA expression of leukocyte-type diacylglycerol (DAG) kinase alpha in PMN from LAP patients (4.6 +/- 1.7 relative units, n = 6, p = 0.007) compared with asymptomatic individuals (51 +/- 27 relative units, n = 7). DAG kinase activity was monitored by DAG phosphorylation and individual DAG molecular species were quantified using liquid chromatography and tandem mass spectrometry-based lipidomics. DAG kinase activity was also significantly decreased (73 +/- 2%, p = 0.007) and correlated with increased accumulation of 1,2-diacyl-sn-3-glycerol substrates (p = 0.01). These results implicate defects in both PMN transendothelial migration and PMN DAG kinase alpha signaling as disordered functions in LAP. Moreover, they identify a potential molecular lesion in PMN signal transduction that may account for their aberrant responses and tissue destruction in this disease.

Efficacy of a Fluoridated Hydrogen Peroxide-Based Mouthrinse for the Treatment of Gingivitis: A Randomized Clinical Trial

BACKGROUND

A randomized clinical trial was performed to test the efficacy of a fluoridated hydrogen peroxide-based mouthrinse on gingivitis and tooth whitening in a two-phase study. The first phase (28 days) included the experimental gingivitis phase; the second phase (5 months) was the oral hygiene phase, which included rinsing.

METHODS

A total of 99 subjects were included in the study and were randomly assigned to receive either placebo or test mouthrinse. Clinical measures were chosen to reflect the gingival health and tooth whiteness in an intent-to-treat study design. Statistical analyses of clinical parameters related to gingival health and tooth color were conducted, using the method of generalized estimating equations (GEE), with an exchangeable working correlation to accommodate tooth-level data. Baseline differences between the groups were adjusted. Microbial samples taken at the beginning and at the end of the study were analyzed by DNA-DNA hybridization technique, to determine whether there was any adverse shift in supragingival flora.

RESULTS

Eastman bleeding index, modified gingival index, intensity of stain, and extent of stain were significantly reduced in the test group at 6 months compared to baseline (P < 0.05). In contrast, only the Eastman bleeding index was significantly reduced in the control group (P < 0.05). The reduction in the index of gingival inflammation for the test group was significantly greater than for the control group (P = 0.004). Subjects using the test rinse were also six times more likely to exhibit an improvement in tooth color after 6 months than were subjects using placebo (P = 0.002). As a result of the clinical evaluations and microbial analysis, test mouthrinse was found to be safe during a 6-month period.

CONCLUSION

The results of this study indicate that the fluoridated hydrogen peroxide-based mouthrinse effectively whitens teeth and significantly reduces gingivitis.

Localized aggressive periodontitis is linked to human chromosome 1q25

Localized aggressive periodontitis (LAP; previously known as localized juvenile periodontitis) is one of the rapidly progressive periodontal diseases. Certain forms of familial LAP show a simple Mendelian pattern of transmission. However, no gene mutation has been identified to be responsible for the LAP phenotype. As an initial step to identify a gene mutation associated with LAP, we have performed genetic linkage analysis with four multigenerational families exhibiting the LAP phenotype. Affected individuals in the families were identified based on clinical and laboratory criteria in an attempt to define a homogeneous phenotype, since the clinical presentation of LAP may represent a manifestation of a heterogeneous group of diseases. The LAP phenotype is linked to a DNA marker, D1S492, with LOD score 3.48, theta=0.00. The haplotype analysis of the chromosome interval associated with D1S492 indicates that a LAP locus is located between D1S196 and D1S533 on chromosome 1, covering about 26 million DNA basepairs. We have also examined the DNA sequence of prostaglandin-endoperoxide synthase 2 (PTGS2 or cyclooxygenase 2, COX2) since prostaglandin 2 (PGE2), the product of COX2, is upregulated in LAP patients and COX2 is located between D1S196 and D1S533. No mutation in COX2 was identified in the patients.

Identification of mRNAs for the various diacylglycerol kinase isoforms in neutrophils from patients with localized aggressive periodontitis

BACKGROUND

Diacylglycerol kinase (DGK) metabolizes diacylglycerol (DAG), an endogenous activator of protein kinase C, to phosphatidic acid. We have previously reported increased DAG in neutrophils from patients with localized aggressive periodontitis (LAP) associated with reduced DGK activity. This reduction could be related to a mutation, post-translational modification, differential expression, or lack of expression of a particular isoform(s).

OBJECTIVE

The aim of this study was to identify the mRNAs for DGK isoforms in normal and LAP neutrophils.

METHODS

The alpha-, gamma-, and delta-isoforms of DGK were identified by polymerase chain reaction (PCR) using specific oligonucleotide primers for each isoform. The PCR products were isolated and sequenced for comparison to published sequences to confirm the validity of the PCR reaction. Total RNA was isolated from LAP and normal neutrophils, and northern blotting and semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) was used to examine the level of mRNA for each isoform.

RESULTS

No major differences were found in the isoform pattern between resting normal and LAP neutrophils. However, the levels of mRNA for the alpha- and gamma-isoforms of DGK were increased in normal neutrophils while slightly decreased in LAP cells upon stimulation with N-formyl-methionyl-leucyl-phenylalanine (fMLP).

CONCLUSION

These data suggest that alterations in the mRNAs for the various isoforms of DGK during cell stimulation and the involvement of DGK that is expressed in multiple forms are subject to a variety of regulatory/control mechanisms and these mechanisms may explain the role of the 'primed' neutrophil phenotype associated with LAP.

Oral findings, treatment and follow-up of a case with major aphthous stomatitis (Sutton's disease)

Major aphthous stomatitis (Sutton's disease) is a clinical variant of recurrent aphthous stomatitis, which is noted for its high morbidity. Since the etiology of the disease is not clear, many therapies have been attempted. However, the controversial results hinder the adoption of a single mode of management. We present a 13-year-old boy with Sutton's disease, who was successfully treated with a combination of burst systemic prednisone (1 mg/kg/day for five days, thereafter half dose on alternate days for one week) and topical triamcinolone (four rinses a day). He continued the mouth rinses with the same interval. At the end of the first month, significant healing was observed and gradual tapering was recommended on the condition that the ulcers were well-controlled. The maintenance of steroid rinse once a day provided a symptom-free period of one year. Neither any withdrawal signs nor side affects were observed. Therefore, we think that this regimen should be considered as the treatment of choice in Sutton's disease along with a close follow-up even in childhood.