The neutrophil: mechanisms of controlling periodontal bacteria

Modulation of interleukin-8 activity by gingipains from Porphyromonas gingivalis: implications for pathogenicity of periodontal disease

Gingipains are the major cysteine proteinases synthesized by Porphyromonas gingivalis which, in soluble form, are able to initially convert IL-8 (77 amino acid residues) to a more potent species truncated at the amino terminus, followed by slow degradation and destruction of chemokine biological activity. In contrast, the same enzymes when associated with bacterial outer-membrane blebs (vesicles), instantly degrade this chemokine. This division of enhancing and inactivating activity between soluble and membrane-bound gingipains can cause the compartmentalization of pro- and anti-inflammatory reactions to distal and proximal positions from bacterial plaque, respectively, which may explain why, despite the massive neutrophil accumulation at periodontitis sites, there is no elimination of infection.

Differential expression of interleukin-8 and intercellular adhesion molecule-1 by human gingival epithelial cells in response to Actinobacillus actinomycetemcomitans or Porphyromonas gingivalis infection

Little is known regarding the molecules expressed by gingival epithelial cells that are involved in initiating and maintaining inflammation following the interaction with periodontal pathogens. Thus, we investigated the effect of Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis infection on the expression of neutrophil chemoattractant interleukin 8 (IL-8) and the adhesion molecule intercellular adhesion molecule-1 by gingival epithelial cells. The data revealed that both IL-8 and intercellular adhesion molecule-1 expression increased after infection with A. actinomycetemcomitans (IL-8: 2- to 7-fold; intercellular adhesion molecule-1: 2.5- to 3.7-fold). IL-8 secretion reached a maximal level 6 h after the infection and the expression subsequently decreased to basal level. The increased cell surface intercellular adhesion molecule-1 expression started at 4 h after infection and reached a maximal level 14 h after the infection. In contrast, the expression of both molecules rapidly decreased 2 h after challenge with P. gingivalis. This opposite influence of A. actinomycetemcomitans and P. gingivalis infection on the expression of IL-8 and intercellular adhesion molecule-1 by gingival epithelial cells suggests that A. actinomycetemcomitans infection may initiate the recruitment of neutrophils, whereas the P. gingivalis infection may retard this process and therefore demonstrate a distinct perspective of virulence.

Sulfide enhancement of PMN apoptosis

Hydrogen sulfide is a toxic metabolite released by several bacterial agents under anaerobic conditions. In the present paper, we investigated the effects of sulfide on polymorphonuclear cell (PMN) apoptosis, a mechanism suggested for limiting the toxic potential of neutrophils in inflammatory sites. We showed that 1 mM sulfide (concentration not conditioning PMN viability) is able to enhance the apoptotic fate of human granulocytes by increasing: i) the number of cells containing pyknotic nuclei, ii) the internucleosomal cleavage, and, iii) the intensity of tubulin immunofluorescence staining. The sulfide effect is partially prevented by ionomycin and this finding is consistent with the hypothesis of the inhibiting role played by high levels of cytosolic calcium in PMN apoptosis modulating.

Phagocytic function of salivary PMN after smoking or secondary smoking

Alterations in polymorphonuclear leukocyte (PMN) functions, such as phagocytosis, chemotaxis, and oxidative burst, play a pivotal role in periodontal pathogenesis. In addition, previous studies have demonstrated a strong relationship between smoking and periodontal disease. In the present study, the effect of cigarette smoking or passive smoking (secondary smoking) on the phagocytic function of salivary PMN (SPMN) was investigated. Twenty volunteers with clinically healthy gingiva (10 smokers, 10 non-smokers) participated in this study. In a small room, the smokers and passive smokers (non-smokers) were instructed to smoke and breathe, respectively, in an identical, specific way for about 4 minutes. SPMN was isolated immediately before and after smoking or passive smoking. PMN was then incubated with fluoresbrite beads for 45 minutes at 37 degrees C and the phagocytic status estimated by using a flow cytometer. Cell viability was determined by trypan blue exclusion (smokers before smoking: 88.3%: smokers after smoking: 89.6%: non-smokers before passive smoking: 89.0%; non-smokers after passive smoking: 89.4%). In both smokers and passive smokers, the proportion of phagocytic cells increased between before and after smoking (smokers before: 33.2%; after: 42.1%: passive smokers before: 36.2%: after: 44.1%). Both increases were statistically significant (P < 0.01). These results demonstrate that the phagocytic activity of SPMN intensifies after smoking and passive smoking. They also suggest that certain substances in cigarette smoke, perhaps nicotine, overstimulate the host response in the oral cavity.

The modification of alveolar bone proteoglycans by reactive oxygen species in vitro

Reactive oxygen species (ROS) are being increasingly implicated in the connective tissue degradation associated with chronic inflammatory conditions, such as periodontal disease. The present study investigated the effects of ROS on the proteoglycans (PG) of alveolar bone which are important structural components within the periodontium. PG were isolated from ovine alveolar bone and exposed to increasing concentrations of hydrogen peroxide (H2O2) or to a hydroxyl radical (.OH) flux for 1 h or 24 h, and the degradation products examined for depolymerisation and chemical modification of the PG structure. ROS were demonstrated to be capable of degrading alveolar bone PG in vitro, the .OH species resulting in greater modification than H2O2. The degradative effects observed included cleavage of the protein core and depolymerisation of the GAG chains. The core proteins were more susceptible to degradation than the GAG chains in the presence of H2O2 alone, although both the core proteins and the GAG chains were extensively degraded in the presence of a .OH flux for both 1 h and 24 h. Exposure of the PG to .OH for 24 h resulted in significant modification to the amino acid composition with decreases in the proportion of leucine and the complete loss of proline, tyrosine and phenylalanine evident. The results highlight the potential role of ROS as an important mechanism in considering the pathology of periodontal tissue destruction.

The correlation between the numbers of some bacteria in human oral cavity and blood neutrophil count

The correlation between the number of blood polymorphonuclear granulocytes (PMNs) and the counts of oral bacteria in 92 children (33 girls and 59 boys), aged 4-15 was investigated. The groups of children comprised 44 healthy individuals and 48 children suffering from acute lymphoblastic leukaemia who were given intensive antileukaemic chemotherapy. It was found that while the number of PMNs in blood decreased, the counts of Streptococcus spp., Staphylococcus spp., mutans streptococci, Lactobacillus spp., and Actinomyces spp. in the saliva tended to increase. The similar reciprocal correlation between the number of blood PMNs and the counts of these bacteria in the saliva was found in the group of healthy children. We concluded that the blood PMNs, by influencing the number of oral PMNs which control bacteria in this habitat, influence also the number of some groups of bacteria there.

Measurement of prostaglandin E2 and leukotriene B4 in the gingival crevicular fluid

The arachidonic acid metabolites prostaglandin E2 (PGE2) and leukotriene B4 (LTB4) are inflammatory mediators which are likely to be involved in the pathogenesis of periodontal disease. PGE2 mediates vasodilatation, increases vascular permeability, enhances pain perception by bradykinin and histamine, alters connective tissue metabolism and enhances osteoclastic bone resorption. LTB4 causes the accumulation of inflammatory cells in the inflamed sites, and degranulation of polymorphonuclear leukocytes.

OBJECTIVE

To measure gingival crevicular fluid (GCF) levels of PGE2, LTB4 and periodontal health.

METHODS

The periodontal condition of 24 subjects was evaluated on the basis of plaque index, gingival index, probing depth, and attachment level. GCF samples were collected from one or two site(s) of each sextant per subject and the volume was measured using Periotron 6000. Samples were then assayed for PGE2 and LTB4 using a competitive enzyme immunoassay. Mean PGE2 and LTB4 levels were determined for each subject and group means compared.

RESULTS

Significant differences in the levels of PGE2 and LTB4 were found between patients with periodontitis, and non-periodontitis individuals (P < 0.001). The PGE2/LTB4 levels were positively correlated with the clinical parameters (P < 0.01) and reduced markedly after phase 1 of the periodontal treatment (P < 0.01). The total amount and concentration (ng ml-1) of LTB4 was positively correlated with the gingival index (P < 0.01).

CONCLUSIONS

These results indicate that the levels of PGE2 correlated with the severity of the periodontal status, and the levels of LTB4 correlated with gingival inflammation. Thus, our data suggest that the total amounts of PGE2/LTB4 may be good indicators for periodontal inflammation.

Healing response to non-surgical periodontal therapy in patients with diabetes mellitus: clinical, microbiological, and immunologic results

The aim of the present study was to monitor clinical, microbiological, medical, and immunological effects of non-surgical periodontal therapy in diabetics and healthy controls. 20 IDDM (insulin dependent, n = 7) or NIDDM (non-insulin dependent, n = 13) diabetic patients (median duration 11.5 years, range of HbA1C: 4.4-10.6%) with moderate to advanced periodontal disease and 20 matched healthy control patients, were subjected to supragingival pretreatment and subsequent subgingival therapy. Periodontal examinations (API, PBI, BOP, PPD, PAL), microbiological examinations (culture), medical routine examinations, and immunological examinations (oxidative burst response of PMNs to TNF-alpha and FMLP) were performed at baseline, 2 weeks after supragingival, and 4 months after subgingival therapy. 4 months after completion of non-surgical therapy, the following compared to baseline significant (p < or = 0.05) changes (delta) of clinical parameters (median) were found in diabetic patients versus control patients: deltaAPI (30.4% versus 36.3%), deltaPBI (22.9% versus 24.2%), deltaBOP (39.5% versus 46.9%). The median % per patient of pockets with PPD > or = 4 mm decreased from 41.9% to 28.3% in diabetics, and from 41.6% to 31.8% in controls. Microbiologically, similar reductions of periopathogenic bacteria were found in diabetics and controls. Neither periodontal data nor the oxidative burst response of PMNs showed any significant difference (p > 0.05) between diabetics and control patients. In this study, periodontal therapy had no significant influence on medical data of diabetics. In conclusion, this study indicates that metabolically well-controlled diabetics might respond to non-surgical periodontal therapy as well as healthy control patients.

Degradation of glycosaminoglycans by reactive oxygen species derived from stimulated polymorphonuclear leukocytes

The effect of reactive oxygen species (ROS), generated by in vitro stimulation of isolated PMN upon the main GAG components of mineralised and non-mineralised connective tissues was investigated. PMN were isolated from whole blood and the production of the ROS superoxide (O2.-) and hydroxyl radicals (.OH) was stimulated by the addition of phorbol myristyl acetate (PMA) and PMA/FeCl3-EDTA chelate respectively and their production assessed over a 24 h period. The glycosaminoglycans (GAG), hyaluronan, chondroitin 4-sulphate and dermatan sulphate, were exposed to the ROS fluxes, incubated at 37 degrees C for 1 h and 24 h. GAG fragmentation was examined by gel exclusion chromatography and modification to hexuronic acid and hexosamine residues determined. Stimulation of PMN with PMA resulted in a burst of O2.- production for 1 h, which was sustained at a reduced level for 24 h. Fragmentation of GAG was observed for all GAG examined. Modification to the GAG was evident, with hyaluronan being more susceptible to loss of GAG residues than sulphated GAG. Modification of sugar residues increased with the incubation time and loss of the hexuronic acid residues was greater than loss of hexosamine residues. Addition of FeCl3-EDTA chelate, which led to the generation of .OH and was sustained over the 24 h period, demonstrated similar trends of GAG modification although increased degradation and loss of hexosamine and hexuronic acid were observed. GAG chains are constituents of PGs and their modification is likely to affect the function of these macromolecules and be of importance in considering the pathogenesis of inflammatory diseases, including periodontal diseases.

Lipoproteins of Treponema denticola: their effect on human polymorphonuclear neutrophils

The presence of lipoproteins and lipooligosaccharides in Treponema denticola, an oral spirochaete associated with periodontal diseases, was investigated. T. denticola ATCC 35404 and the clinical isolate GM-1 were metabolically labeled with [3H]-cis-9-octadecenoic acid and extracted with the non-ionic detergent Triton X-114. The extract was phase separated, precipitated with acetone and delipidated to remove non-covalently bound lipid (dLPP). In T. denticola ATCC 35404, sodium dodecyl sulfate polyacrylamide electrophoretic separation followed by autoradiography showed [3H]-cis-9-octadecenoic acid incorporation in bands with apparent molecular masses of 14, 20, 26, 31, 38, 72 and 85 kDa and a broad band running from 113 kDa to the top of the gel. This last band resolved into a 53 kDa [3H]-cis-9-octadecenoic acid band upon heating for 10 min, at 100 degrees C. The structural relationship of the outer sheath major oligomeric polypeptide of strain ATCC 35404 and the 53 kDa protein was demonstrated immunologically. Antibodies against the 113 kDa component of the oligomer cross-reacted with the 53 kDa protein. Proteinase K degraded the [3H]-cis-9-octadecenoic acid bands with the exception of the 14 kDa. The 14 kDa was also the major [3H]-fatty acid labeled compound found in the water phase following phenol-water extraction of whole T. denticola ATCC 35404 cells. This compound was purified from the water phase by gel filtration followed by hydrophobic chromatography. Chemical analysis showed that hexadecanoic acid was the predominant fatty acid bound to T. denticola lipoproteins. In the GM-1 strain [3H]-cis-9-octadecenoic acid incorporation was observed in the 116 kDa and 14 kDa bands. dLPP from strain ATCC 35404 caused an enhanced (0.8-8 micrograms/ml) luminol dependent chemiluminiscence (LDCL) effect in human polymorphonuclear neutrophils (PMN) which could be related to protein concentration. The addition of dLPP to PMN together with FMLP at submaximal concentration (1 microM) resulted in a synergistic activation of LDCL. At 21 micrograms/ml, dLPP also induced lysozyme release by the PMN at approximately 30% of the release induced by the chemotactic peptide at 1 microM. In addition, dLPP (21 micrograms/ml) increased additively the release of lysozyme caused by 1 microM FMLP. The release of beta-glucuronidase was not affected. The modulation of neutrophil activity was abolished by preincubation of dLPP with proteinase K. The purified 14 kDa had no effect on either LDCL or exocytosis of lysosomal enzymes of PMN. These data strongly suggest that T. denticola possesses several lipoproteins including outer sheath major oligomeric polypeptides (113-234 kDa) and a lipooligosaccharide of molecular mass of 14 kDa. In addition, an enriched lipoprotein fraction from this oral spirochaete modulates oxygen dependent and independent mechanisms for controlling microorganisms by human PMN.

Effect of amine and stannous fluoride on human neutrophil functions in vitro

Amine fluoride (AmF)- and stannous fluoride (SnF2)-containing products were found to have a therapeutic effect on gingivitis and periodontitis. This effect was suggested to correlate with the antibacterial activity of the fluoride compounds. However, their effect on inflammatory cell function can also play a role in the therapeutic effect on gingival inflammation. The present study was designed to test the effects of AmF, SnF2, and an AmF/SnF2 combination on the function of human peripheral blood neutrophils, as compared with effects of chlorhexidine and salicylic acid. Neutrophils were isolated from human blood by ficoll centrifugation followed by dextran sedimentation. The neutrophils were pre-incubated with AmF, SnF2, or AmF/SnF2, followed by stimulation with fMLP. Cell vitality was verified by trypan-blue exclusion (> 95% vitality at all tested concentrations). Superoxide production was measured by cytochrome C reduction and the enzymatic activity of lysozyme and beta-glucoronidase by optical density measurement of substrate conversion. The results showed that AmF, SnF2, or AmF/SnF2 enhanced by two- to three-fold the superoxide release from fMLP-stimulated human neutrophils. Furthermore, the effective concentration of the AmF/SnF2 combination was several-fold lower than that of AmF or SnF2 alone (10 nM for AmF, 0.5 microM for SnF2, and 3 pM for SnF2/AmF). On the other hand, chlorhexidine and salicylic acid were found to reduce superoxide production by the cells. All the tested compounds had no effect on granular enzyme release by the stimulated neutrophils. The results suggest that AmF and SnF2 enhance the oxygen-dependent antibacterial activity of neutrophils. This effect may contribute to a more efficient elimination of bacteria from the periodontal environment, resulting in improvement in gingival health.

Loss of Fc gamma receptor and impaired phagocytosis of polymorphonuclear leukocytes in gingival crevicular fluid

Immunoglobulin G type II and III receptors (Fc gamma RII and Fc gamma RIII) are essential for polymorphonuclear leukocytic (PMNs) phagocytosis. Our previous study demonstrated a downregulation of Fc gamma RIII on PMNs in gingival crevicular fluid (GCF). To determine whether this receptor downregulation may contribute to the periodontal host defence borne by PMNs, we examined the correlation between Fc gamma RII and Fc gamma RIII expressions and the phagocytic capacity of GCF-PMNs. In order to verify at which level of cellular events the loss of Fc gamma R occurs, we quantified mRNA levels to assess a de novo synthesis of these receptors. GCF was collected from 21 patients with adult periodontitis by gingival crevicular washing. Autologous peripheral blood (PB) PMNs served as control. Surface expressions of Fc gamma Rs and phagocytic capacity via Fc gamma Rs were analysed by flow cytometry. The difference in Fc gamma R mRNA levels between GCF- and PB-PMNs was assessed by reverse transcription polymerase chain reaction (RT-PCR). The amplified products were visualized by agarose gel electrophoresis and the endproduct yields were quantified by computerized image-analysis. Both Fc gamma RII and Fc gamma RIII expressions and phagocytic capacity on GCF-PMNs were significantly lower than those on PB-PMNs (p < 0.001). The downregulation of Fc gamma Rs on GCF-PMNs significantly correlated with the phagocytic capacity (r = 0.66 for Fc gamma RIII, p < 0.01; r = 0.50 for Fc gamma RII, p < 0.05). The mRNA level of Fc gamma RIII of GCF-PMNs was significantly lower than that of PB-PMNs (p < 0.05). Thus, GCF-PMNs are characterized by the decreased surface expressions and mRNA levels of Fc gamma Rs, and the impaired phagocytosis.

The role of Actinobacillus actinomycetemcomitans in the pathogenesis of periodontal disease

Periodontal disease consists of a constellation of complex bacterium-host cell interactions. One example of these oral pathogens, Actinobacillus actinomycetemcomitans, has an arsenal of putative virulence determinants that account for its potent periodontopathogenicity. Of these determinants, invasion of host cells and leukocytotoxicity have been studied extensively.

Children, adolescents and periodontal diseases

OBJECTIVES

This manuscript attempts to critically review current literature regarding the natural history, aetiology and pathogenesis of the common periodontal diseases to affect children and adolescents. The logic behind the emergence of a new classification in the early 1990s is explained and potential problems with the interpretation of such systems outlined.

DATA SOURCES

The manuscript focuses upon recent developments, reported in the international periodontal literature, aimed at unraveling the molecular basis for this group of diseases. The concept of one disease type progressing with time to another disease within the same individual is discussed, and early data presented that indicate the possibility of microbial transmission from deciduous to permanent dentition's within a subject.

CONCLUSIONS

It is concluded that differing classification systems for adolescent and childhood periodontal diseases may lead to confusion within the dental profession, unless the clinical and molecular basis for such diseases is fully understood. Further advances in basic research using molecular biology tools should assist in our understanding of the aetiopathology at a molecular level and hopefully lead to the development of new treatment strategies.

Generalized prepubertal periodontitis. A report of 4 cases with the immunological findings

The clinical and immunological data from 4 patients with generalized prepubertal periodontitis are presented. The peripheral blood neutrophil chemotaxis was measured using zymosan activated sera as the chemoattractant. All of the 4 patients have shown depressed neutrophil chemotaxis compared to those of the healthy controls. Peripheral blood lymphocyte subpopulations were analysed by double-coloured flow cytometry using monoclonal antibodies for the receptors CD2, CD3, CD4, CD8, CD19, CD29, CD45RA+, 34,29dK, CD56. CD11b/CD18. Lymphocytes bearing CD3 receptors showed a significant decrease compared to those of the controls. Natural killer cells were lowered in 3 of the 4 cases. All of the patients showed a higher increase in CD11b/CD18 expression. The evaluation of CD11b/CD18 receptor in peripheral blood leukocytes may be of help explaining the rôle of neutrophils in the pathogenesis of the disease.

Periodontitis associated with chronic renal failure: a case report

Chronic renal disease is associated with well-documented impairments in polymorphonuclear leucocyte (PMN) function. PMNs are important in defending the periodontium against plaque infections. This report discusses a case of periodontitis in a patient with chronic renal failure. It presents treatment provided and 1-year follow up. It shows that periodontal infections in patients with depressed PMN function could still be managed successfully with standard periodontal treatment emphasizing plaque control.

Alterations in phagocyte function and periodontal infection

A review of phagocytic cells-polymorphonuclear leukocytes and monocytes-in the inflammatory process is presented. Examples of phagocyte defect-related pathology serve as a framework for understanding the role of these cells in periodontal infection. The role of alterations in neutrophil function in localized juvenile periodontitis is presented as a model system for understanding periodontal pathology as a result of host-related functional abnormalities. Two topical alternative hypotheses for periodontal breakdown are presented in which macrophage control of the chronic lesion is altered by an absence of T cells or the influence of bacterial superantigens.

Effect of antibodies on chemiluminescence and on killing of Streptococcus sobrinus by polymorphonuclear leukocytes

The effect of a polyclonal antiserum and OMVU10, a monoclonal antibody reactive with Antigen B of Streptococcus sobrinus, on the interaction of polymorphonuclear leukocytes with S. sobrinus was studied, using chemiluminescence and bacterial killing assays. Increased stimulation of neutrophils as measured in the chemiluminescence assays was established when S. sobrinus was preincubated with polyclonal antiserum or when polyclonal antiserum was added to the reaction mixture. Higher counts were measured in comparison to preimmune serum. After 90 min, 52% of S. sobrinus preincubated with polyclonal antiserum was killed. Killing was also increased when polyclonal antiserum was added to the reaction mixture in comparison to the controls. No killing was found when bacteria were preincubated with OMVU10 or when OMVU10 was added to the reaction mixture in comparison to Clone 24, a control antibody.

Papillon-Lefèvre syndrome. Analysis of neutrophil chemotaxis

Papillon-lefèvre syndrome (PLS) is described as the association of palmar-plantar hyperkeratosis with precocious periodontal disease which results in exfoliation of primary and permanent dentitions. This study was planned to assess the chemotaxis of peripheral blood neutrophils in 7 patients (3 females and 4 males) with Papillon-Lefevre syndrome. The neutrophil chemotaxis was analyzed using the zymosan activated serum (ZAS) assay. Chemotaxis and spontaneous migration measurements were compared to those of the healthy control subjects. The peripheral blood neutrophil chemotaxis and spontaneous migration were depressed in all patients with Papillon-Lefèvre syndrome. The decreased chemotaxis of peripheral blood neutrophils strongly suggests that the neutrophils may act as one of the important key determinants in the pathogenesis of severe periodontal destruction in patients with PLS.

pH changes observed in the inflamed gingival crevice modulate human polymorphonuclear leukocyte activation in vitro

Previous studies have noted a positive correlation between gingival inflammation and crevicular pH, which reportedly varies from 6.5 to 8.5. In the present study, we characterized the manner in which deviation from the "physiological" pH of blood (7.2) influences activation of chemotaxis, phagocytosis, superoxide generation, and degranulation by human polymorphonuclear leukocytes (PMNs). Purified PMNs were suspended in HEPES-buffered balanced salts solutions adjusted to pH 6.7, 7.2, 7.7, or 8.2. In a modified Boyden chamber, the chemotactic response to fMet-Leu-Phe was maximal at pH 7.2. In comparison, chemotaxis was significantly depressed at pH 7.7 and pH 8.2 (P < 0.05), but was not significantly different at pH 6.7. Activation of the respiratory burst by fMet-Leu-Phe was optimal at pH 7.2, but was significantly depressed at pH 6.7 and 8.2 (P < 0.05). pH had little effect on N-acetyl-beta-glucosaminidase release from primary granules. However, lactoferrin release from the secondary granules of fMet-Leu-Phe-activated PMNs was significantly lower at pH 7.2 than at pH 6.7 or 8.2 (P < 0.05). Moreover, phagocytosis of opsonized bacteria was significantly lower at pH 7.2 than at pH 7.7. In addition to these effects on functional activation, extracellular pH influenced the magnitude of intracellular Ca2+ mobilization. Peak fMet-Leu-Phe-induced Ca2+ levels were significantly higher at pH 8.2 than at pH 7.2 (P < 0.01). These findings suggest that the pH of the periodontal environment can selectively influence PMN activation, thereby altering the balance between bacteria and the host response.

Increased release of free oxygen radicals from peripheral neutrophils in adult periodontitis after Fc delta-receptor stimulation

The release of free oxygen radicals and degranulation was studied in neutrophils from 14 patients with adult periodontitis and 14 age- and sex-matched healthy controls. The neutrophils were activated by Fc gamma-receptor stimulation, using Staphylococcus aureus opsonized with gamma globulin. Release of oxygen radicals was measured as luminol-enhanced chemiluminescence. Degranulation was assessed as release of elastase, measured with a specific substrate and as release of lactoferrin measured with ELISA. The neutrophils from the patients showed a significantly higher chemiluminescence and a slightly higher release of elastase, whereas the release of lactoferrin was the same in both groups. In contrast, the ratio between the 2 degranulation products, elastase and lactoferrin, was significantly higher in the group with periodontitis. A flow cytometric analysis of the membrane expression of the adhesion molecules CD 11a, CD 11b, CD 15, CD 16, CD 35 and Mel 14 showed no differences in the median immunofluorescence between the 2 groups. This study showed a more than 2-fold higher release of free oxygen radicals from Fc-gamma-receptor stimulated neutrophils compared with healthy controls, which indicates a specific neutrophil-associated host response in adult periodontitis.

Role of the capsular polysaccharide-like serotype-specific antigen in resistance of Actinobacillus actinomycetemcomitans to phagocytosis by human polymorphonuclear leukocytes

Serotype b-specific polysaccharide antigen (SPA) of Actinobacillus actinomycetemcomitans Y4 consists of D-fucose and L-rhamnose. To clarify the role of SPA in phagocytosis of the organism by human polymorphonuclear leukocytes (PMNs), monoclonal antibodies (MAbs) against SPA and SPA-defective mutants, which were constructed by inserting the transposon Tn916 into strain Y4, were used in a chemiluminescence (CL) assay and a phagocytic killing assay. The CL responses of human PMNs to strain Y4 were very low, and the organism was not killed by PMNs. In contrast, SPA-defective mutants induced strong CL responses. The addition of immunoglobulin G MAbs against Y4 SPA enhanced significantly both the CL responses to strain Y4 and the killing of the organism in the presence of complement. The CL responses to SPA-defective mutants were little affected by the addition of these MAbs. We conclude that SPA of A. actinomycetemcomitans plays an important role in the resistance to host defenses by PMNs.

Levels of interleukin-1 beta and interleukin-8 in gingival crevicular fluids in adult periodontitis

Recent in vitro findings indicate that cytokines represent an important pathway of connective tissue destruction in human periodontitis. The biological effects of interleukin-1 beta (IL-1 beta) and interleukin-8 (IL-8) are relevant in this regard, and the objective of this study was to compare the levels of these molecules in gingival crevicular fluids (GCF) from patients with adult periodontitis (experimental group) and from individuals with clinically healthy gingiva (control group). GCF was collected for 30 seconds using a periopaper strip and the volume of the sample determined. Following elution of the fluid, assays for IL-1 beta and IL-8 were carried out by ELISA. The concentrations (ng/ml) of cytokines were calculated in the original volume of GCF on each strip. The total amounts (pg/site) of cytokines were expressed as the concentrations multiplied by volumes of GCF: The total amounts of IL-1 beta and IL-8 of the experimental group were significantly higher than the control group. The total amounts of both cytokines were markedly reduced following phase 1 periodontal treatment. The clinical parameters were positively related to the total amounts of IL-1 beta and IL-8. IL-1 beta concentrations and total amounts were also positively related to IL-8 suggesting that the GCF IL-8 levels are influenced by local IL-1 beta activities. These data indicate that the total amounts of IL-1 beta and IL-8 exhibited dynamic changes upon severity of periodontal disease. The levels of IL-1 beta and IL-8 in GCF are valuable in detecting the inflammation of periodontal tissue.

The relationship between elastase and lactoferrin in healthy, gingivitis and periodontitis sites

OBJECTIVES

To compare the relative amounts of elastase (primary polymorphonuclear leucocyte granule constituent) and lactoferrin (secondary PMN granule constituent) in the gingival crevicular fluid (GCF) of healthy, gingivitis and periodontitis sites.

DESIGN

This cross-sectional study looked at the two GCF constituents in three categories of disease status within the same subject.

MATERIALS AND METHODS

Patients with chronic adult periodontitis were screened and those exhibiting all three types of sites ie periodontally healthy, gingivitis and periodontitis sites were recruited (n=10) and had GCF collected from the three sites. Lactoferrin and elastase were measured in eluates of GCF by enzyme-linked immunosorbent assay.

RESULTS

The absolute amount of lactoferrin measured in ng per 30 s samples was significantly lower in healthy and gingivitis sites as compared to periodontitis sites; however this difference failed to reach significance when the concentration of lactoferrin in GCF was used as the analytical unit. No significant differences were found for elastase levels at any sites when expressed as either absolute amounts or concentrations. Secondary granule release, as evidenced by lactoferrin levels, occurs during cell migration and the process is independent of primary granule release, which is thought to correlate with PMN activation. The relationship between granule constituents in the samples showed significant differences, the highest lactoferrin/elastase ratio being at periodontitis sites (P<0.001).

CONCLUSIONS

These findings imply a change in the relative amounts of elastase and lactoferrin released at different disease level sites, wth an almost 10-fold increase in the proportion of lactoferrin to elastase in periodontitis sites over healthy and gingivitis sites. This variation in the release by PMNs of primary and secondary granule constituents may indicate alterations in PMN function in different disease environments.

Interleukin-1 beta gene expression in human oral polymorphonuclear leukocytes

Oral polymorphonuclear leukocytes (PMN) were obtained from 10 adult donors in good oral health using a method employing repeated mouth rinse collection. Interleukin-1 beta (IL-1 beta) mRNA was detected in freshly obtained cells by blot hybridization of total cellular RNA with a biotin labeled cDNA probe. Supernates from oral PMN placed in culture for 3 hours contained substantial amounts of IL-1 beta measured by ELISA. Significantly greater numbers of PMN and amounts of PMN-derived IL-1 beta were obtained from the same donors 2 hours subsequent to an oral sucrose challenge (3.23 x 10(6) vs. 1.57 x 10(6) mean PMN number, P = 0.004; 59.80 vs. 20.05 mean pg/ml IL-1 beta, P = 0.036, respectively). However, the elevated levels of IL-1 beta were due to the higher cell number rather than to increased production by individual cells. Stimulation of oral PMN with recombinant granulocyte-macrophage colony stimulating factor did not enhance their cytokine production. In most instances. IL-1 beta production by oral PMN was dramatically greater than that of their blood counterparts. These findings suggest that oral PMN are an important source of IL-1 beta, which plays a central role in oral immunity and inflammatory disease states.

The effect of initial periodontal therapy on salivary platelet-activating factor levels in chronic adult periodontitis

Platelet-activating factor (PAF), a potent phospholipid inflammatory mediator, is increased in the mixed saliva of subjects with periodontal disease and correlates with the extent of oral inflammation. The present study was designed to provide a longitudinal evaluation of the effect of initial periodontal therapy (home care instruction, prophylaxis, and scaling/root planing) on salivary PAF levels in chronic adult periodontitis patients (n = 15). Mixed saliva was collected prior to, during, and after initial therapy and was utilized to assess PAF levels after lipid extraction and fractionation as well as to histologically assess the number of polymorphonuclear leukocytes (PMN). PAF activity was determined in bioassay relative to authentic PAF (1-O-hexadecyl-2-acetyl-sn-glycero-3-phosphocholine; 16:0-alkyl-PAF). Initial salivary PAF levels (12.1 +/- 2.8 pmole equivalents of 16:0-alkyl-PAF/ml saliva; mean +/- SE) decreased following supragingival plaque control (9.6 +/- 2.4) and were further reduced following scaling and root planing (5.7 +/- 1.4). In parallel, salivary PMN levels were significantly reduced and clinical estimates of periodontal disease were significantly improved; i.e., there was a decrease in the percentage of sites with both bleeding on probing (from 46.1 +/- 4.6% of sites at pretreatment to 25.9 +/- 2.6% after scaling and root planing) and probing depths > or = 4 mm (from 16.7 +/- 1.9% of sites to 10.3 +/- 1.2%). Thus, initial periodontal therapy reduced salivary PAF levels in concert with improvements in clinical estimates of marginal and submarginal periodontal inflammation suggesting that PAF may participate in inflammatory events during periodontal tissue injury and disease.

IgG antibody subclass response to Porphyromonas gingivalis outer membrane antigens in gingivitis and adult periodontitis

Porphyromonas gingivalis is an important oral pathogen with a strong association with adult periodontitis. Significant titers of specific IgG antibodies to P. gingivalis can be found in the sera of both gingivitis and periodontitis patients. Since IgG subclasses have different biological characteristics, the present study dealt with the serum IgG subclass response to outer membrane antigens of P. gingivalis. Western blot analysis of P. gingivalis outer membrane was carried out using 20 adult periodontitis and 20 age- and sex-matched gingivitis patients. Antibodies in sera of both adult periodontitis and gingivitis patients recognized 38 antigen bands, ranging in molecular mass from 11.1 to 161 kDa. IgG2 was the predominant antibody subclass response in both patient groups in terms of the numbers of outer membrane antigens recognized, followed by IgG3, IgG1, and IgG4. More antigens in all IgG subclasses except IgG4 were recognized in adult periodontitis cases. Of the 23 antigens identified by IgG2 antibodies, 9 were recognized predominantly in adult periodontitis and 3 in the gingivitis group. In the IgG1 subclass, 4 antigens were recognized predominantly in the adult periodontitis group while only 1 antigen was recognized significantly more in the gingivitis group. The IgG3 response identified 14 antigens ranging in molecular mass from 11.1 to 61.2 kDa in both groups. Ten antigens were recognized significantly by the adult periodontitis group. The lowest response was seen by IgG4 antibodies, with only 3 antigens of molecular mass 61.2, 52.3, and 38.8 kDa recognized, the latter two significantly in the adult periodontitis group.(ABSTRACT TRUNCATED AT 250 WORDS)

Polyamines found in gingival fluid inhibit chemotaxis by human polymorphonuclear leukocytes in vitro

Putrescine and spermidine occur at concentrations approaching 1 mM in gingival fluid at diseased periodontal sites. Previous work demonstrates that these polyamines potentiate Ca2+ signaling in polymorphonuclear leukocytes (PMNs), resulting in enhanced degranulation and superoxide generation. The present study extends this work by characterizing the effects of polyamines on PMN chemotaxis and phagocytosis, in which Ca2+ signaling plays a less defined regulatory role. Putrescine (1 mM) and spermidine (0.1 to 0.5 mM) significantly inhibited chemotaxis to fMet-Leu-Phe and C5a (P < 0.05). This inhibition was not strongly related to any effect polyamines have on PMN adhesion, actin polymerization, or formyl peptide receptor expression. Neither putrescine nor spermidine had a significant impact on phagocytosis of opsonized bacteria by PMNs. Thus, at concentrations similar to those found in gingival fluid, polyamines could potentially inhibit recruitment of PMNs to diseased pockets without impairing their ability to engulf invading bacteria.

Variations in crevicular fluid elastase levels in periodontitis patients on long-term maintenance

Granulocyte elastase was determined in the gingival crevicular fluid (GCF) of 18 periodontitis patients. They initially had similar severity of disease but had responded differently to 5-yr maintenance, 13 responders and 5 non-responders. A total of 102 sites were investigated and categorized as: i) consistently healthy, ii) healthy after treatment, iii) gingivitis, and iv) periodontitis, according to clinical criteria. GCF elastase activity was determined with a granulocyte-specific substrate. The sites from non-responders had consistently higher elastase levels than the corresponding category of sites from responders, despite similar gingival inflammation and periodontal destruction, with the exception of consistently healthy sites. Within the non-responders, the periodontitis sites had higher elastase levels than the gingivitis sites commensurate with probing depth, while no difference existed between gingivitis sites and sites healthy after treatment, despite a difference in probing depth. In contrast, in the responders similar elastase levels were found at the periodontitis sites and gingivitis sites despite difference in probing depth, while both diseased sites had higher elastase levels than the sites healthy after treatment, commensurate with probing depth. This study suggests that increased granulocyte-specific elastase levels in GCF may serve as a diagnostic marker for refractory periodontitis patients.

The immunopathology of chronic inflammatory periodontal disease

Chronic inflammatory periodontal disease is known to be under the control of the immune response. However, the precise mechanism of the immunopathogenesis of this lesion has not yet been fully elucidated. In this review, the regulatory role of both lymphoid and non-lymphoid cells as well as cytokines and accessory molecules in the course of chronic inflammatory periodontal disease is discussed. Finally, based upon previous evidences, an attempt to establish a model of chronic inflammatory periodontal disease is made herein.

Identification of CG-1, a natural peptide antibiotic derived from human neutrophil cathepsin G

Cathepsin G is a neutral serine protease of the granzyme B family which is found in human PMN, cells known to be important in the defense of the periodontium against periodontal bacteria. We propose that cathepsin G serves as a "pro-antibiotic" containing peptide domains which express selective antibiotic properties. In this study, we used HPLC to separate the low-molecular-weight peptides derived from the ultrafiltrate of a granule extract from unstimulated PMN. One of the peptides exhibited intense bactericidal activity as determined by radial diffusion overlay assay (against Escherichia coli ML-35P), an amino-terminal sequence "RVSSFLPWIR...", and a 3.1-kDa molecular mass determined by electrospray ionization-mass spectrometry. The sequence and mass are consistent with the C-terminus of cathepsin G deduced by cDNA analysis. These findings support the hypothesis that antibiotic peptides derived from cathepsin G occur naturally in human PMN. Since this is the first naturally occurring antibiotic peptide derived from cathepsin G, we designate it "CG-1".

Increased intracellular levels of lysosomal beta-glucuronidase in peripheral blood PMNs from humans with rapidly progressive periodontitis

Release of potent lysosomal enzymes by degranulation of polymorphonuclear leukocytes (PMNs) in host gingiva may contribute significantly to tissue destruction and the pathogenesis of periodontal disease. A pilot study established that peripheral blood PMNs from humans with rapidly progressive periodontitis (RPP) contained significantly increased amounts of intracellular lysosomal beta-glucuronidase as compared to healthy controls. This investigation gained insight into the question: are the increased levels of beta-glucuronidase in persons with RPP an a priori genetically determined PMN characteristic, or a reactive phenomenon induced by the periodontal disease process during granulopoiesis? Twelve healthy controls and twelve otherwise healthy individuals with RPP participated in a repeated measures design to T0 (initial, baseline), T1 (four weeks after disease control therapy), and T2 (two months later). At each visit clinical indices (GI, pocket depths, GCF flow, plaque index) were performed and peripheral blood obtained. PMNs were isolated and suspended as 5 x 10(6) cells in 2.0 ml of HBSS. PMN suspensions were tested for total intracellular beta-glucuronidase, degranulation induced by 1 x 10(-6)M and 5 x 10(-7) M FMLP challenges, and unchallenged for non-specific enzyme release. PMNs from individuals with RPP contained significantly higher absolute amounts of beta-glucuronidase and released greater absolute amounts at FMLP challenge at T0, T1, and T2 compared to controls. No relationship was found between any of the clinical indices and beta-glucuronidase levels and no pattern was discovered relating to the repeated measures over time. We conclude that RPP peripheral blood PMNs contain elevated levels of beta-glucuronidase that are not induced by the periodontal disease process.

Identification and possible function of cathepsin G in gingival crevicular fluid from chronic adult periodontitis patients and from experimental gingivitis subjects

The levels of cathepsin G in gingival crevicular fluid (GCF) from chronic adult periodontitis patients and experimental gingivitis subjects were determined both by activity measurement using N-benzoyl-(DL)-phenylalanine-2-naphthyl ester as a substrate and by enzyme immunoassay using anti-human cathepsin G IgG. The activity level of cathepsin G in GCF of both periodontitis and experimental gingivitis has no significant correlation with all measured clinical parameters. Western immunoblotting using antibodies specific for cathepsin G or alpha 1-proteinase inhibitor revealed that the difficulty in demonstrating the association of its activity with the severity of these diseases was due largely to formation of the enzyme-inhibitor complexes. By contrast, statistically significant positive correlation was found between cathepsin G content in GCF of periodontitis, which was determined by enzyme immunoassay, and such clinical parameters as the GCF volume, the gingival index and probing depth. The increased cathepsin G content with increasing severity of periodontal inflammation was markedly diminished by the initial treatment. Although no significant activity was detectable in GCF of experimental gingivitis, a rapid increase of the immunoreactive cathepsin G was found in GCF at 3-5 d after refraining from oral hygiene measures, which rapidly decreased by 10 d. The progressively increased cathepsin G between 10th and 21st d rapidly decreased by cleaning of the teeth. The results indicate that cathepsin G is involved in the host's defensive mechanism against the invasion of etiologic microbes and/or the development of either periodontitis or gingivitis.

Neutrophil lysosomal nonoxidative microbicidal proteins in early-onset periodontitis

The purpose of this study was to evaluate whether the reduced microbicidal activity of polymorphonuclear leukocytes (neutrophils) in patients with early-onset periodontitis is associated with a deficiency of nonoxidative microbicidal proteins. Neutrophils from 10 patients with early-onset periodontitis and 8 healthy control subjects were assessed for elastase isozymes 1 through 4, cathepsin G isozymes 1 through 4 and defensins (HNP-1, HNP-2 and HNP-3) using cationic and acid urea polyacrylamide gel electrophoresis. The results showed that both the total content and the relative distribution of elastase and cathepsin G isozymes was normal in neutrophils of patients with early-onset periodontitis. However, the HNP-3 content was significantly reduced in neutrophils from patients with generalized early-onset periodontitis. These findings indicate that the impaired microbicidal activities of neutrophils in patients with early-onset periodontitis does not appear to be based on an elastase or cathepsin G abnormality in neutrophils. Due to the high variability of HNP-1 + 2 and HNP-3 in neutrophils of control subjects, the reduced HNP-3 content in neutrophils probably plays a minor role in the pathogenesis of generalized early-onset periodontitis.

The in vitro effect of human polymorphonuclear leukocyte azurophil granule components on natural killer cell cytotoxicity

We previously demonstrated that human polymorphonuclear leukocyte (PMN) secretions are capable of activating and inhibiting natural killer cell (NK) cytotoxicity depending on the eliciting PMN stimulus. Serum-opsonized zymosan induced PMN to secrete substances that enhanced NK activity in vitro. Serum-opsonized zymosan stimulates the release of PMN azurophil granules, which contain both human neutrophil peptides (HNPs) and neutral serine proteases (NSPs). When HNPs and NSPs were tested for their ability to activate NK cells in peripheral blood lymphocytes, all but cathepsin G consistently enhanced cytotoxicity above control values. HNP-induced cytotoxicity was significantly enhanced within 12 h, peaking at approximately 24 h. Of the HNPs, HNP-1 was the most potent activator, enhancing NK activity at 1.25 micrograms/ml. Interleukin-2 and interferon-gamma were not involved in this activational process, as antibodies to interleukin-2 and interferon-gamma did not block activation by HNPs and NSPs, and interleukin-2 receptor expression was unaltered after 24 h of incubation. Enzymatically inactivated elastase and cathepsin G produced equivalent activational effects to their active counterparts. Antisera to elastase and cathepsin G decreased but did not eliminate NK activation over untreated peripheral blood lymphocytes. These data suggest that certain PMN azurophil granule components, including HNPs and NSPs directly increase the cytotoxic activity of NK cells.

Neutrophil defects as risk factors for periodontal diseases

There are several hypotheses proposed for the etiologic mechanisms causing periodontal diseases. These include a paradigm in which all individuals are equally susceptible to one or several pathogenic bacteria; a second paradigm that holds that all bacteria are equally virulent and that host susceptibility determines onset of disease; or a combination of the above. In this review, we analyze the role of neutrophil dysfunction as a risk factor for the onset of periodontitis. Both intrinsic or genetically inherited abnormalities of neutrophils and acquired neutrophil abnormalities are considered. While a large body of data implicates neutrophil dysfunction, either intrinsic or acquired (bacterially or extrinsically induced), as a significant risk factor for the periodontal diseases, clear, prospective, longitudinal epidemiologic studies to evaluate this association remain to be performed.

Oxygen-dependent modulation of release and activity of polymorphonuclear leukocyte granule products

Polymorphonuclear leukocytes are important in the defense against the anaerobic microflora of infected gingival pockets. One part of this defense is release of antibacterial granule products by polymorphonuclear leukocytes into the pockets. The aim of the present study was to compare the efficiency of polymorphonuclear leukocytes in releasing granule products under aerobic and anaerobic conditions. Polymorphonuclear leukocytes were exposed to serum-opsonized zymosan under aerobic and anaerobic conditions. The levels of released granule products were determined by combining measurements of activity with enzyme-linked immunosorbent assays. The level of released elastase was twice as high in anaerobic as in aerobic reaction mixtures. A similar difference was not detected for myeloperoxidase. However, myeloperoxidase was inactivated after its release under aerobic conditions. The release of lactoferrin was an efficient under aerobic as under anaerobic conditions. The effect of aerobic conditions on the release of elastase and the inactivation of myeloperoxidase could be ascribed to oxidants formed in the myeloperoxidase-H2O2-chloride system. Also, the activity of the released cytoplasmic enzyme lactate dehydrogenase was inactivated by oxidants formed in the myeloperoxidase-H2O2-chloride system. These findings suggest that, in the anaerobic environment of the gingival pocket, elastase and possibly also other azurophilic granule products are released in higher amounts than under fully oxygenated conditions. In this environment, the released products may also escape inactivation by the myeloperoxidase-H2O2-chloride system.

Chemoluminescence generation and MTT dye reduction by polymorphonuclear leukocytes from periodontal disease patients

Alterations of polymorphonuclear leukocytes (PMNs) functions have been reported in patients with severe forms of some periodontal disease. In this study we evaluated the chemoluminescence generation and MTT dye reduction by human PMN in patients with juvenile periodontitis (JP), rapidly progressive periodontitis (RPP) and adult periodontitis (AP) during protein kinase C (PKC) activation or during the phagocytosis of opsonized zymosan. The results demonstrated that only PMNs of JP patients showed a decreased chemoluminescence generation and MTT dye reduction during the phagocytosis of opsonized zymosan (p < 0.05). The time to reach the maximal peak during the PKC activation on the chemoluminescence reaction was evaluated and JP PMNs patients demonstrated a depressed value (7.0 +/- 0.4 min) compared with healthy volunteers (13.8 +/- 0.5 min). The etiology and importance of such cellular alterations in the immunopathogenesis of the periodontal disease are discussed.

New clinical diagnostic strategies based on pathogenesis of disease

The pathogenesis of periodontal tissue destruction involves the orchestrated sequential activation of several components of the host response, each of which have the potential for providing diagnostic information regarding the health or disease status of the periodontium. These events include the bacterial triggering of serum components, the release of vasoactive compounds, the recruitment of inflammatory cells, the activation of phagocytes, the local secretion of immunoglobulins and inflammatory mediators, as well as connective tissue remodeling. For purposes of diagnosis, much attention has been directed toward the measurement of local levels of specific byproducts of the pathogenic process either within the tissues or in the adjacent crevicular fluid. These are site-directed assessments of the local concentration of these byproducts, and with the important exception of antibody levels, very few byproducts of the periodontal pathogenic process have been studied on a systemic level. However, since the risk associated with periodontal disease progression is primarily patient-based and secondarily site-based, there is an increasing need to identify patients at risk for intervention strategies. Furthermore, there are substantial data that periodontal diseases are specific infections that occur in an appropriately susceptible host. The expression of periodontal disease has a strong genetic component, which presumably defines the host's response thereby affecting susceptibility. For this reason, there is increased interest in defining those elements of the host response which result in susceptibility to disease. The ultimate objective of a diagnostic strategy is to identify patients who are potentially at risk for acquiring disease to enable preventive measures.

Flurbiprofen in the prevention and treatment of experimental gingivitis

A clinical trial was undertaken to examine the effects of a potent cyclooxygenase inhibitor, flurbiprofen, on both developing and established gingivitis in humans. 21 subjects with healthy gingiva abstained from all oral hygiene procedures for 21 days. 7 subjects were prescribed flurbiprofen, 50 mg b.d. beginning from baseline and a control group (Cl, n = 14) were given placebo. Gingival redness and bleeding on probing were assessed at baseline, 7, 14 and 21 days. Crevicular fluid (GCF) samples were also taken to determine concentrations of PGE2, TxB2 and LTB4 at baseline and at 21 days. Results show that flurbiprofen significantly inhibited the development of redness and bleeding (p < 0.001) effects which were associated with a significant inhibition of TxB2 (p < 0.05). There were no apparent flurbiprofen effects on GCF-PGE2 or GCF-LTB4 during this 21-day gingivitis, model To assess the effects of flurbiprofen on established experimental gingivitis, the model was extended to 28 days. On day 21, the Cl group was subdivided into 2 groups of 7 subjects. One group was prescribed flurbiprofen (50 mg b.d.) for 7 days and controls (C2) continued to take placebo. All subjects continued to abstain from tooth cleaning. Pretreatment (day 21) and post-treatment (day 28) comparisons showed that flurbiprofen again significantly inhibited bleeding (p < 0.001), but did not affect redness. Control subjects demonstrated a significant elevation in gingival bleeding on day 28, and this was associated with significant rises in GCF-PGE2 (p < 0.001), GCF-TxB2 (p < 0.01) and GCF-LTB4 (p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)