Collagenase and collagenase inhibitor activities in crevicular fluid of patients receiving treatment for localized juvenile periodontitis

Collagenolytic activity was monitored in crevicular fluids of 3 patients receiving treatment for localized juvenile periodontitis (LJP) and in 3 control, clinically healthy patients to study relationships between mammalian collagenase and disease activity. It was found that tissue collagenase activity initially was significantly higher in diseased patients compared to controls, but that in II of 13 diseased sites the activity decreased substantially following clinical treatment. In control sites, active collagenase was generally low or absent. Latent collagenase concentrations tended to remain high in diseased sites and in sites with gingival inflammation. Collagenase inhibitor activity was found only in clinically healthy sites sampled from both control subjects and LJP patients throughout the experiment, and in diseased sites following various phases of treatment. The collagenolytic activity observed was typical of mammalian collagenase in that the primary degradation products of collagen were 3/4- and 1/4-fragments. However, additional specific fragmentation of native collagen 3/4-fragments was also observed, which could be attributed to a novel collagenolytic activity generally present in crevicular fluid in a latent form. The results of this study suggest that the determination of active collagenase and collagenase inhibitor in crevicular fluid might be useful in assessing both the disease status of periodontal tissues and the efficacy of clinical treatment.     

Correlation of collagenolytic enzymes and inhibitors in gingival crevicular fluid with clinical and microscopic changes in experimental periodontitis in the dog

The quadrants of the jaw in 2 beagle dogs had various forms of periodontal disease induced by ligatures placed around second, third and fourth premolars in one quadrant and, 2.5 months later, around the same teeth in a second quadrant; gingivitis was allowed to develop in a third quadrant after 4 months; the fourth quadrant served as a healthy control. Crevicular fluid flow, plaque index, gingival index, attachment levels and recession were determined at intervals and collagenolytic activity measured in the fluid. The dogs were killed after 5 months and sections of each site prepared for histomorphometry. Clinically-inflamed and degenerating sites had significantly higher collagenolytic activities (p less than 0.001), lower collagenase inhibitor activities and greater fluid flow than control sites which showed abundant inhibitor activity and minimal active enzyme. Periodontitis sites had higher active enzyme, compared to latent enzyme activities, whereas latent collagenase was predominant in control and gingivitis sites. The collagenolytic activities in periodontitis sites fluctuated with time, suggesting a cyclical pattern. Active enzyme activities correlated strongly with gingival crevicular fluid flow and attachment loss. Periodontitis sites had much more inflammatory-cell infiltration than control and gingivitis sites (p less than 0.001). Thus periodontal disease may be monitored by examination of crevicular fluid collagenolytic enzymes, inhibitors and fluid flow, and these criteria may prove more meaningful than current clinical criteria.     

Human gingival crevicular fluid keratin at healthy, chronic gingivitis and chronic adult periodontitis sites

Abstract The present study was designed to determine, in a cross-sectional study, whether there was any relationship between the keratin-positive material in gingival crevicular fluid and the clinical periodontal status. Keratins were selected as putative indicators of degradation of epithelial cells cytoskeletal proteins. Keratin positive material was determined by enzyme-linked immunosorbent assay-in 42 subjects exhibiting clinical sites of health, chronic gingivitis and chronic periodontitis. The concentration of keratin in parotid saliva was also measured for each subject. Keratin concentration in gingival crevicular fluid samples was significantly greater at sites exhibiting signs of gingivitis and periodontitis compared with healthy sites. No differences were detected between sites exhibiting gingivitis and periodontitis. No differences were found between the 3 groups for the saliva keratin-positive material which was significantly less than that detected in gingival crevicular fluid. These results suggest that gingival crevicular fluid keratin concentration may serve as a marker of gingival damage.     

The short-term effectiveness of non-surgical treatment in reducing protease activity in gingival crevicular fluid from chronic periodontitis patients

OBJECTIVES: The aim of this study was to evaluate the short-term effect of non-surgical periodontal treatment on protease activity in gingival crevicular fluid (GCF) of patients with chronic periodontitis. MATERIAL AND METHODS: After clinical examination, in which pocket probing depth, probing attachment level, plaque and bleeding indices were recorded, gingival fluid samples from 21 chronic periodontitis patients were collected from gingivitis (GP) and periodontitis (PP) sites with an intracrevicular washing method. Samples were taken in the same way from a group of patients with gingivitis alone (GG). The periodontitis patients received non-surgical periodontal treatment and were re-evaluated 30 days later. We compared elastase and collagenase activities before and after treatment. The former activity was measured with a low-weight substrate (S-2484) and inhibited by alpha-1-antitrypsin. Matrix-metalloproteinase-8 (MMP-8) was measured with an ELISA and collagenolytic activity with fluorescein-conjugated collagen type I as substrate. RESULTS: All clinical parameters showed a significant improvement after treatment (p<0.05) which was accompanied by a significant reduction in the values of total elastase activity, free elastase, MPP-8 and collagenolytic activity in both GP and PP sites (p<0.05). However, the latter sites continued to have higher levels of MMP-8 and collagenolytic activity than the former ones after treatment. The free elastase activity and the proportion of free elastase in GP and PP samples after treatment remained higher than in untreated GG samples. CONCLUSION: This study shows that the clinical improvements after non-surgical treatment are accompanied by reductions in protease and neutrophil activities.     

Initial characterization of neutral proteinases from oral spirochetes

Intermediate size oral spirochetes were isolated and cultured from subgingival plaque of periodontitis patients utilizing a membrane separation and rifambin selection technique. Neutral salt extracts of the spirochetes were assayed for proteolytic activity against collagen types I and IV, gelatin, and synthetic elastase and trypsin substrates. Type IV collagen obtained from lens capsule basement membrane was degraded to small peptides by the spirochete proteinases. No marked degradation of type I collagen was found when incubations were performed at 25°C. The extracts were able, however, to activate latent collagenase obtained from human gingival fibroblasts and to degrade further the ¼ and ¾ fragments resulting from the collagenase cleavage. Denatured collagen was also degraded by the extracts. High trypsin-Iike activity and relatively lower elastase-like enzyme activity were also present in spirochete extracts. The results show that oral spirochetes have a potential for degradation of several proteins and that they may, therefore, have an active role in tissue destruction during periodontal disease.     

Collagenolytic activity in crevicular fluid from patients with chronic adult periodontitis, localized juvenile periodonitis and gingivitis, and from healthy control subjects

Collagenolytic activity in gingival crevicular fluid (GCF) sampled from 25 healthy control subjects, 25 gingivitis, 25 chronic adult periodontitis (CAP) and 8 LJP patients was correlated with clinical disease parameters using both the site and the patient as sampling units. Among patients collagenase activity increased with the severity of the disease in the order: healthy < gingivitis < periodontitis. Among sites , significant correlation was found between GCF collagenase activity and pocket depth in CAP and LJP, but not in gingivitis patients. Enzyme activity was also correlated with GI score in LJP, but not in CAP and gingivitis patients. In a subset of 10 patients in each of the healthy, gingivitis and CAP groups the association of enzyme activity and crevicular fluid volume (flow) was examined. Significant correlation was found between fluid volume and pocket depth in CAP patients, and between fluid volume and GI score in gingivitis patients, but no association was observed between collagenase activity and fluid volume. The Collagenolytic enzyme was shown to be a genuine vertebrate collagenase derived from unidentified host cells. The concentration of the enzyme in crevicuar fluid from CAP patients was in the order of 10 μg/ml.     

Tetracycline inhibition identifies the cellular origin of interstitial collagenases in human periodontal diseases in vivo

Mammalian interstitial collagenases (E.C.3.4.24.7) are considered as key initiators of collagen degradation in periodontal diseases. However, the cellular sources of collagenases present in gingival crevicular fluid have not been completely clarified. Resident fibroblasts and epithelial cells as well as infiltrating neutrophils and monocyte/macrophages are potential sources of the enzymes. We have recently found significant differences in tetracycline inhibition between human neutrophil and fibroblast interstitial collagenases. To address the cellular source of collagenase present in gingival crevicular fluid in 2 distinct periodontal diseases, we studied the tetracycline inhibition of collagenase in gingival crevicular fluid of patients with localized juvenile periodontitis and adult periodontitis. Gingival crevicular fluid samples were collected from deep (greater than 5 mm) periodontal pockets and assayed for collagenase in the presence of 0-1000 microM doxycycline as well as a chemically modified tetracycline devoid of antimicrobial activity (4-de-dimethylaminotetracycline). The drug concentration required to inhibit 50% of collagenase activity (IC50) in localized juvenile periodontitis gingival crevicular fluid was 280 microM for doxycycline and 470 microM for 4-de-dimethylaminotetracycline. Significantly lower values, 10-20 microM, were obtained for collagenase in gingival crevicular fluid of patients with adult periodontitis. We propose that systemic tetracycline levels are efficient inhibitors of collagenase in gingival crevicular fluid in affected sites of patients with adult periodontitis but not of patients with localized juvenile periodontitis and that the fibroblast type interstitial collagenase is the predominant collagenase type in gingival crevicular fluid in affected sites of patients with localized juvenile periodontitis and the neutrophil collagenase in adult periodontitis gingival crevicular fluid.(ABSTRACT TRUNCATED AT 250 WORDS)     

Further evidence that tetracyclines inhibit collagenase activity in human crevicular fluid and from other mammalian sources

Recently, a new mechanism was proposed to explain the therapeutic efficacy of tetracyclines in periodontal disease— that specifically these antibiotics directly inhibit the activity of collagenase (and possibly other collagenolytic enzymes) produced by the host tissues resulting in a reduced rate of collagen breakdown (Golub et al. 1983). In the current studies, the effect of tetracyclines (minocycline, doxycycline, tetracycline) on collagenolytic enzyme activity was examined in human periodontal pockets and in several animal systems. In the clinical studies, gingival crevicular fluid (GCF) was collected on filter paper strips from individual periodontal pockets, the volume measured with the Periotron 6000, and the Gingival Index and pocket depth scored immediately thereafter at the same sites. The strips were incubated with [³H-methyi] collagen maintained in solution (or with ¹⁴C-glycine labeled collagen Fibrils), and the radiolabeled collagen degradation products measured in a liquid scintillation spectrometer, Using the techniques of SDS-PAGE and fluorography, the GCF was observed to generate collagen degradation products characteristic of those produced by mammalian collagenase, a finding consistent with previous studies. Both minocycline and tetracycline therapy reduced GCF collagenolytic activity about 70% during the initial weeks of treatment; the clinical parameters also showed improvements at the same time periods. This reduction in collagenolytic activity had largely regressed by 5 weeks after terminating tetracycline therapy and by 19 weeks after minocycline therapy, in the absence of other forms of periodontal treatment. In a preliminary study, 50 days of doxycycline treatment also reduced GCF collagenase activity, an effect which persisted for at least 2 months (but less than 1 year) after terminating its administration. In several studies involving experimental animals, the tetracyclines (1) in vivo, were found to reduce the pathologically excessive collagenase activity in gingiva and skin of diabetic rats; and (2) in vitro, directly inhibited the activity of collagenases from rat PMNL's and rabbit chondrocytes. The data in the current and our previous studies (Golub et al. 1983, Gomes, Golub & Ramamurthy 1984) continue to support the hypothesis that tetracyclines, by directly inhibiting collagenolytic enzyme(s) activity, may be therapeutically useful in treating diseases, such as periodontitis, characterized by excessive collagen breakdown.     

α1-Proteinase inhibitor in gingival crevicular fluid of humans with adult periodontitis: serpinolytic inhibition by doxycycline

The serum protein, α₁-proteinase inhibitor (α₁PI), defends the host against serine proteinases, e.g. PMN elastase. Using a rabbit anti-serum against human α₁-PI, this protein in GCF was quantified from a standard curve constructed from dot-blot analysis and characterized by Western blot. GCF was collected on filter paper strips from healthy (H), gingivitis (G) and adult periodontitis (AP) patients, then extracted with Tris/NaCl/CaCl₂ buffer, pH 7.6. α₁-PI concentration increased with G and was highest in AP subjects. H sites only showed intact α₁-PI (52 kDa); no degradation fragments (48 kDa) were detected. In G and AP subjects, α₁-PI degradation fragments were seen in 17% and 71% of GCF samples, respectively. Both collagenase and α₁-Pl-degrading activities in GCF increased with severity of inflammation (GCF flow). Moreover, the α₁-PI degrading (or serpinolytic) activity was characterized as a matrix metalloproteinase, probably collagenase, based on its in vitro response to a panel of different proteinase inhibitors including doxycycline. We propose: (1) that collagenase promotes periodontal breakdown not only by degrading collagen, but also by depleting α₁-PI regulation of elastase and other serine-proteinases, thereby favoring a broader attack on extracellular matrix (ECM) constituents, and (2) based on a recent longitudinal double-blind study using the techniques described above for α₁-PI analysis, that low-dose doxycycline administration to humans with adult periodontitis can inhibit this broad cascade of ECM degradation.     

Salivary collagenase. Origin, characteristics and relationship to periodontal health

Saliva collected from subjects with healthy and with diseased periodontium was assayed for collagenase activity by incubation at 25 degrees C with soluble type I, II or III collagen. The degradation products were analyzed by separation in SDS-polyacrylamide gel electrophoresis followed either by protein staining or by exposure of the dried gel to X-ray film in the case of radioactively labeled type I collagen. Collagenase of vertebrate type was detected in the whole saliva of all subjects but not in parotid, sublingual or submandibular fluids. Most of the collagenase was in the soluble fraction of saliva that also contained factors which both activated and inhibited the enzyme. The salivary collagenase resembled the collagenase of human PMNs and gingival sulcular fluid in its molecular size of 70,000 daltons, in its activation by gold thioglucose and in its tendency to degrade types I and II collagens over type III collagen. Before periodontal treatment, the saliva of periodontitis patients had significantly higher collagenase than after treatment. In periodontitis, collagenase existed mainly in the active form, while in the healthy mouths most of the enzyme was latent but could be activated by sulfhydryl reagents or proteolytically with trypsin, and chymotrypsin but not by human plasma kallikrein or plasmin. In some of the samples from untreated periodontitis patients bacterial collagenase may have been present in small quantities. Most of the collagenase in the saliva from all subjects appeared to originate from PMNs entering the oral cavity through the gingival sulcus.     

Collagenolytic activity of crevicular fluid and of adjacent gingival tissue.

The fluid in and gingival tissue lining periodontal pockets were collected from male patients undergoing periodontal therapy. The collagenolytic activity of the crevicular fluid, and the ability of the gingiva in culture to degrade (a) an exogenous collagen substrate, and (b) endogenous collagen newly synthesized and labeled with H3-hydroxyproline, were related to the severity of gingival inflammation. Although inflammation appeared to have only a slight effect on gingival collagenolytic activity and on the turnover of collagen newly synthesized in culture, a marked effect was observed on the collagenase activity in the crevicular fluid. This study suggests that the collagen destructive activity of the periodontal lesion can be assessed by monitoring crevicular fluid collagenolytic activity.     

Levels of specific immunoglobulin G to Porphyromonas gingivalis in gingival crevicular fluid are related to site disease status

Titers of immunoglobulin G (IgG) directed against Porphyromonas gingivalis in gingival crevicular fluid of 40 periodontitis patients were measured at three sites in each patient (healthy, gingivitis and periodontitis) by enzyme-linked immunosorbent assay. When paired analyses were performed using Wilcoxon signed-rank tests, periodontitis sites were found to have lower median titers than gingivitis sites. Both systemic and locally-produced antibodies contribute to the overall gingival crevicular fluid antibody profile. Albumin, in contrast, is derived only from serum, and thus this protein serves as an indicator of serum contribution to gingival crevicular fluid. Correction was therefore made for systemic input to the gingival crevicular fluid IgG profile by expressing the results per unit of albumin. When this was done, periodontitis sites were also found to have significantly lower antibody levels than gingivitis sites. These findings suggest that a failure of local antibody production or reduction in quantities, by, for example, degradation by bacterial proteases, may contribute to the change from a gingivitis to a periodontitis lesion.     

慢性牙龈炎及慢性牙周炎治疗前后患牙龈沟液中t-PA及PAI活性的比较

目的 :比较慢性牙龈炎、慢性牙周炎患牙治疗前后龈沟液中t PA及PAI活性。方法 :选择慢性龈炎(n =2 8)及慢性牙周炎 (n =5 2 )患牙两组 ,在治疗前及治疗后收集龈沟液 (GCF)并记录临床指标 ,用发色底物法测定GCF中t PA及PAI的活性。结果 :t PA活性在牙龈炎组治疗前后差异无显著性 ,在牙周炎组治疗前后差异有显著性 ;PAI活性在牙龈炎组及牙周炎组治疗前后差异均有显著性 ;PAI/t PA比值在牙周炎组治疗前后差异有显著性 ,牙龈炎组治疗前后差异无显著性。结论 :PAI可以作为判断牙龈炎症程度及治疗效果较为客观的指标 ;牙周炎组中治疗后PAI/t PA显著降低的部位是否预示较差的预后 ,尚需进一步纵向研究。     

Initial characterization of a neutral metalloproteinase, active on native 3/4-collagen fragments, synthesized by ROS 17/2.8 osteoblastic cells, periodontal fibroblasts, and identified in gingival crevicular fluid

Analysis of collagenolytic activity in gingival crevicular fluid (GCF) has revealed the presence of an enzyme capable of fragmenting native 3/4- and 1/4-collagen cleavage products generated by collagenase. An enzyme with similar activity was also identified in media conditioned by fibroblasts from rat periodontal ligament and gingiva, and by rat osteoblastic cells (ROS 17/2.8, 17/2A, 17/2B). In culture, the enzyme was secreted in a latent form that could be activated by organomercurials. For further characterization of this novel enzyme (MMP-V), the osteoblast proteinase was partially purified. ROS 17/2.8 conditioned medium was harvested daily and the 25%-60% sat. ammonium sulfate fraction chromatographed on an AcA 54 gel filtration column. Latent forms of MMP-V (apparent Mr approximately 54 k) and collagenase (Mr approximately 54 k) were resolved from gelatinase (Mr approximately 76 k) and two collagenase inhibitors (Mr approximately 62 k, approximately 36 k). Activated MMP-V degraded native 3/4-collagen fragments from collagen types I and II in a step-wise manner and was active on denatured collagen. MMP-V showed a divalent cation requirement, was active at neutral pH, and was inhibited by collagenase inhibitor and fetal bovine serum, but not by serine, thiol, or carboxyl proteinase inhibitors. These properties indicate that MMP-V is a member of the matrix-degrading, neutral-metalloproteinase family of enzymes which include collagenase, gelatinase, stromelysin, and telopeptidase. The enzyme may function in the degradation of collagen fibrils by cleaving proteinase-resistant 3/4-collagen fragments that are stabilized by association with neighboring collagen molecules.     

Collagenase activity in gingival crevicular fluid of patients with juvenile periodontitis

The nature and origin of collagenases in gingival crevicular fluid of juvenile periodontitis patients was investigated. Gingival crevicular fluid collected from deep untreated periodontal pockets of juvenile periodontitis patients was found to contain only vertebrate collagenase (EC 3.4.24.7) activity that cleaved soluble type-I and -III collagens into 3/4 and 1/4 length fragments, as analyzed by SDS-polyacrylamide gel electrophoresis. Type II collagen was degraded at a markedly slower rate. This substrate specificity is indicative of collagenases produced by fibroblasts, epithelial cells and macrophages. We have previously found that collagenase in gingival crevicular fluid of adult periodontics patients appears to be mainly derived from polymorphonuclear leukocytes (PMN). The reasons for the apparent difference in collagenase source between the groups were investigated. We examined whether the pathogen characteristic for juvenile periodontitis, Actinobacillus actinomycetemcomitans, can release collagenase from normal human PMNs. All 10 A. actinomycetemcomitans strains tested, freshly isolated from the subgingival plaque of juvenile periodontitis patients, caused release of collagenase from PMNs in vitro. These results suggest that the lack of normally functioning PMNs in the periodontium of juvenile periodontitis patients may result in a colonization of bacteria that activate the resident periodontal cells to produce increased amounts of collagenase.     

Collagenases in gingival crevicular fluid in type 1 diabetes mellitus

BACKGROUND: Studies have demonstrated that high levels of collagenase activity in gingival crevicular fluid (GCF) are associated with degradation of periodontal tissues in progressive periodontitis compared to periodontally healthy tissues. Because the activation of collagenases is an important issue in periodontitis, we have studied the activation of collagenase in gingival crevicular fluid samples of diabetic patients. METHODS: Collagenase activity was studied in human gingival crevicular fluids. Twenty-two poorly controlled diabetic patients (e.g., blood glucose: 11.0+/-0.7 mmol/l; hemoglobin A1c [HbA1c]: 9.6%+/-0.3%) and five well-controlled diabetic patients were compared to six chronic periodontitis subjects and five healthy controls. Collagenase activity against type I collagen was measured using sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis quantitated by laser densitometry. RESULTS: The poorly controlled diabetic patients had more alveolar bone loss than the well-controlled diabetic subjects and controls (P<0.001; t test). The activity of collagenases in GCF in poorly controlled diabetic patients was similar to that seen in chronic periodontitis subjects (P>0.05) but higher than in healthy controls (P<0.01; t test), whereas there was no difference between the well-controlled diabetic subjects and systemically healthy controls (P>0.05; t test). CONCLUSION: Poorly controlled diabetes is strongly related to periodontal tissue destruction, and collagenases in GCF may mediate and reflect this effect.     

Aberrant neutrophil reactions in periodontitis

BACKGROUND: The aim of this study was to compare the activity of neutrophilic granulocytes in patients with severe periodontitis and patients with gingivitis alone. METHODS: The study population comprised 22 patients with gingivitis and 44 with periodontitis. Samples of gingival crevicular fluid (GCF) were collected from untreated patients with gingivitis and from shallow and deep pockets in untreated patients with periodontitis. GCF samples were analyzed for lactoferrin, elastase, matrix metalloproteinase-8 and -9, and collagenolytic activity. RESULTS: The free elastase activity and the neutrophil activity, estimated as the ratio between elastase and lactoferrin, were significantly higher in the samples from the periodontitis patients. These differences were also observed in shallow pockets in periodontitis patients compared to similar pockets in patients with gingivitis. CONCLUSION: This study shows higher levels of free elastase in untreated patients with periodontitis, relative to inflammation-matched controls, which may explain the tissue destruction seen in periodontitis.     

The effect of collagenase-inhibitor complexes on collagenolytic activity of normal and inflamed gingival tissue

Abstract. The effect of serum inhibitors on determinations of collagenolytic activity in culture fluids of healthy (G.I.=0) and mildly inflamed (G.I.=1) gingival tissue was studied. Gingival biopsies obtained at the beginning of the experimental gingivitis period (G.I.=0) and after approximately three weeks of no oral hygiene (G.I.=1) were subjected to tissue culture procedures previously utilized for the determination of collagenolytic activity. Inhibition of collagenase activity was evaluated by denaturing scrum inhibitors retained in culture fluid with sodium thiocyanate or by adding culture fluid from normal and inflamed tissues to a partially purified collagenase preparation.
A decrease in collagenolytic activity was consistently demonstrable in untreated culture fluids of gingival tissue manifesting G.I.=1 as compared lo those exhibiting G.I.=0. When enzyme containing culture fluids were treated with NaSCN. however, no essential difference was detected. While culture fluids from healthy gingiva showed no inhibition of partially purified collagenase, culture fluids from tissues manifesting mild inflammation inhibited enzyme activity by approximately 60 %.
A number of cell types associated with the periodontium have the ability to produce a specific collagenase. The results of this investigation suggest, however, that in vitro determinations of collagenolytic activity in culture fluids of normal and inflamed tissues may be influenced by specific scrum inhibitors.     

Increased interleukin-18 in gingival crevicular fluid from periodontitis patients

INTRODUCTION: This study aimed to measure the levels of interleukin-18 (IL-18) in inflamed shallow sites and inflamed deep sites in patients with periodontitis and to compare the data with results from inflamed shallow sites in patients with gingivitis. A secondary aim was to examine the composition of the subgingival microbiota in the sampled sites. METHODS: Gingival crevicular fluid was collected from five gingivitis sites and five periodontitis sites from 18 patients with chronic periodontitis, and from five gingivitis sites from 15 patients with gingivitis. Samples from each site category were pooled and IL-18 levels were measured using an enzyme-linked immunosorbent assay. The subgingival microbiota was analyzed by checkerboard DNA-DNA hybridization. RESULTS: All clinical parameters and gingival crevicular fluid volumes were higher in periodontitis sites compared with gingivitis sites from patients with periodontitis and gingivitis. The total amount of IL-18 was higher in periodontitis sites than gingivitis sites in both periodontitis (P = 0.018) and gingivitis (P = 0.002) patients and was higher in gingivitis sites from periodontitis patients than in those from gingivitis patients (P = 0.015). There were higher levels of Tannerella forsythia, Porphyromonas gingivalis, and Treponema denticola (red complex species) in periodontitis sites compared with gingivitis sites in both the periodontitis and gingivitis patients (P < 0.001). CONCLUSION: Levels of IL-18 were higher in patients with chronic periodontitis compared with patients with gingivitis, even at sites with similar pocket depths. The presence of similar levels of red complex species in gingivitis sites from periodontitis patients and from gingivitis patients suggested that the higher levels of IL-18 were not associated with a different microbial challenge.     

Increased interleukin‐18 in gingival crevicular fluid from periodontitis patients

Introduction: This study aimed to measure the levels of interleukin‐18 (IL‐18) in inflamed shallow sites and inflamed deep sites in patients with periodontitis and to compare the data with results from inflamed shallow sites in patients with gingivitis. A secondary aim was to examine the composition of the subgingival microbiota in the sampled sites. Methods: Gingival crevicular fluid was collected from five gingivitis sites and five periodontitis sites from 18 patients with chronic periodontitis, and from five gingivitis sites from 15 patients with gingivitis. Samples from each site category were pooled and IL‐18 levels were measured using an enzyme‐linked immunosorbent assay. The subgingival microbiota was analyzed by checkerboard DNA–DNA hybridization. Results: All clinical parameters and gingival crevicular fluid volumes were higher in periodontitis sites compared with gingivitis sites from patients with periodontitis and gingivitis. The total amount of IL‐18 was higher in periodontitis sites than gingivitis sites in both periodontitis (P = 0.018) and gingivitis (P = 0.002) patients and was higher in gingivitis sites from periodontitis patients than in those from gingivitis patients (P = 0.015). There were higher levels of Tannerella forsythia, Porphyromonas gingivalis, and Treponema denticola (red complex species) in periodontitis sites compared with gingivitis sites in both the periodontitis and gingivitis patients (P < 0.001). Conclusion: Levels of IL‐18 were higher in patients with chronic periodontitis compared with patients with gingivitis, even at sites with similar pocket depths. The presence of similar levels of red complex species in gingivitis sites from periodontitis patients and from gingivitis patients suggested that the higher levels of IL‐18 were not associated with a different microbial challenge.