Lactoferrin in the gingival crevice as a marker of polymorphonuclear leucocytes in periodontal diseases

The events that may contribute to subgingival dysbiosis: a focus on the interplay between iron, sulfide and oxygen

This minireview considers the disruption of the host–microbiota harmless symbiosis in the subgingival niche. The establishment of a chronic infection by subversion of a commensal microbiota results from a complex and multiparametric sequence of events. This review narrows down to the interplay between oxygen, iron and sulfide that can result in a vicious cycle that would favor peroxygenic and glutathione producing streptococci as well as sulfidogenic anaerobic pathogens in the subgingival niche. We propose hypothesis and discuss strategies for the therapeutic modulation of the microbiota to prevent periodontitis and promote oral health.

Application of Lactoferrin and α1-Antitrypsin in Gingival Retention Fluid to Diagnosis of Periodontal Disease

OBJECTIVES

Periodontal disease is prevalent and has an inflammation associated with not only oral but also systemic pathologies. The diagnosis by biomarkers is required for clinical practice on periodontal disease. The lactoferrin and α1-antitrypsin were both inflammation-related molecules. The present study investigated the relationship between the periodontal status and the two biomarkers in gingival retention fluid (GRF).

PATIENTS AND METHODS

In 63 subjects with periodontitis, the GRF was sampled from maxillary anterior gingiva using a microbrush for 30 seconds. The lactoferrin and α1-antitrypsin levels in GRF were measured by an enzyme-link solvent immunoassay. Periodontal status was evaluated by probing pocket depth (PD) and bleeding on probing (BOP).

RESULTS

There was a higher level of these biomarkers in saliva (median (ng/mL), lactoferrin: 3611.9, α1-antitrypsin: 4573.3) than in GRF (lactoferrin: 61.0, α1-antitrypsin: 54.7). There was a mild-to-moderate but significantly positive correlation in lactoferrin or α1-antitrypsin between GRF and saliva. There was a positively mild-to-moderate accuracy (area under the curve: 0.60-0.81) of lactoferrin or α1-antitrypsin in GRF or in saliva to distinguish the severity of periodontal status. The cutoff level (ng/mL) of lactoferrin in GRF for detecting ≥30% of PD ≥ 4 mm (moderate periodontitis) was 68.6 and for detecting ≥20% of BOP (clinically active periodontitis) was 61.2. The cutoff level (ng/mL) of α1-antitrypsin in GRF for detecting ≥30% of PD ≥ 4 mm was 54.5 and for detecting ≥20% of BOP was 35.3.

CONCLUSIONS

The data can promote an application of the measurements of lactoferrin and α1-antitrypsin in GRF to clinical practice on periodontal disease.

Oral antimicrobial peptides: Types and role in the oral cavity

Antimicrobial peptides (AMPs) are a wide-ranging class of host-defense molecules that act early to contest against microbial invasion and challenge. These are small cationic peptides that play an important in the development of innate immunity. In the oral cavity, the AMPs are produced by the salivary glands and the oral epithelium and serve defensive purposes. The aim of this review was to discuss the types and functions of oral AMPs and their role in combating microorganisms and infections in the oral cavity.

Lactoferrin: A Roadmap to the Borderland between Caries and Periodontal Disease

Lactoferrin is one of a number of multifunctional proteins that are present in or on all mucosal surfaces throughout the body. Levels of lactoferrin are consistently elevated in inflammatory diseases such as arthritis, inflammatory bowel diseases, corneal disease, and periodontitis. Single-nucleotide polymorphisms (SNPs) in lactoferrin have been shown to be present in individuals susceptible to Escherichia coli-induced travelers' diarrhea and in tear fluid derived from virally associated corneal disease. Here, we review data showing a lactoferrin SNP in amino acid position 29 in the antimicrobial region of lactoferrin that acts against caries associated bacteria. This SNP was initially discovered in African American subjects with localized aggressive periodontitis (LAP) who had proximal bone loss but minimal proximal caries. Results were confirmed in a genetic association study of children from Brazil with this same SNP who showed a reduced level of caries. In vitro data indicate that lactoferrin from whole saliva derived from subjects with this SNP, recombinant human lactoferrin containing this SNP, or an 11-mer peptide designed for this SNP kills mutans streptococci associated with caries by >1 log. In contrast, the SNP has minimal effect on Gram-negative species associated with periodontitis. Moreover, periodontally healthy subjects homozygous for this lysine (K) SNP have lactoferrin in their saliva that kills mutans streptococci and have reduced proximal decay. The review summarizes data supporting the ecologic plaque hypothesis and suggests that a genetic variant in lactoferrin with K in position 29 when found in saliva and crevice fluid can influence community biofilm composition. We propose that, for caries, this SNP is ethnicity independent and protective by directly killing caries-provoking bacteria (reducing proximal decay). However, the clinical effect of this SNP in LAP is ethnicity dependent, destructive (increases LAP incidence), and complex with mechanisms still to be determined.

Lactoferrin levels in gingival crevicular fluid and saliva of HIV-infected patients with chronic periodontitis

AIM

This study compared lactoferrin (LF) levels in the gingival crevicular fluid (GCF) and saliva between HIV-infected and noninfected patients with chronic periodontitis.

METHODS

For each subject, LF levels were analyzed in one shallow site (SS; PD ≤3 mm), one deep site (DS; PD >5 mm) and in resting whole saliva. Two groups, 28 HIV-infected and 10 noninfected, were selected.

RESULTS

Although the salivary LF levels were higher in HIV-infected than in noninfected individuals, especially in AIDS patients, this was not statistically significant (P > 0.05). Subgingival LF levels for SS and DS were lower among HIV-infected individuals, although AIDS patients showed the lowest levels. Age, smoking, gender, T CD4 lymphocytes levels and viral load did not influence subgingival LF levels, neither for SS nor for DP. Positive fungal culture was observed in 24 HIV-infected patients, but only observed in one in the control group. Overall, LF concentration was significantly higher in DS than SS, both in HIV-infected and noninfected individuals (P < 0.05) and salivary LF levels were always higher than GCF levels.

CONCLUSION

The data indicate that LF levels in the GCF and saliva are not different between HIV-infected and noninfected patients with chronic periodontitis.

Effect of periodontal therapy on lactoferrin levels in gingival crevicular fluid

BACKGROUND

The aim of this study was to evaluate lactoferrin quantification as a sensitive and objective method of detecting the degree of periodontal inflammation, oxidative stress and to monitor the effects of periodontal therapy.

METHODS

Fifty subjects were divided into two groups based on gingival index, probing pocket depth, clinical attachment loss and alveolar bone loss: healthy group and periodontitis group with generalized chronic periodontitis. Non-surgical periodontal therapy was rendered and crevicular fluid samples collected at baseline and four weeks after therapy for lactoferrin quantification using enzyme linked immunosorbent assay. The correlation between clinical parameters and lactoferrin levels was drawn and analysed for both groups.

RESULTS

The mean level of crevicular lactoferrin in the periodontitis group was 1857.21 ng/ml. The mean level decreased to 1415.03 ng/ml after treatment. The lowest lactoferrin concentration was seen in the healthy group (75.34 ng/ml). All clinical parameters correlated positively with lactoferrin levels.

CONCLUSIONS

The lactoferrin level was higher in the periodontitis group compared to the healthy group, and reduced with periodontal therapy. Higher levels were associated with higher values of clinical parameters, both before and after therapy. The data indicates that Lactoferrin plays an important role in periodontal disease and crevicular lactoferrin quantification can be a marker for detecting periodontal inflammation, oxidative stress and monitoring periodontal therapy.

Estimation of lactoferrin levels in gingival crevicular fluid before and after periodontal therapy in patients with chronic periodontitis

BACKGROUND

The lactoferrin (LF) is an iron binding protein present specifically and in abundance in the secondary granules of polymorphonuclear leukocytes (PMN's). It has been suggested that LF in crevicular fluid is a useful marker of PMN activity. Hence, this study aimed to estimate the levels of LF in gingival crevicular fluid (GCF) before and after surgical therapy in chronic periodontitis patients to assess the validity of LF in monitoring of treatment results.

MATERIALS AND METHODS

A total of 30 patients with chronic periodontitis having probing depth of ≥5 mm who were scheduled for periodontal surgery were included in the study. The clinical parameters were recorded and GCF samples were obtained 2 weeks after scaling and root planing and 2 weeks after conventional flap technique. The samples collected were then assayed for LF using Enzyme-linked immunosorbent assay (ELISA).

RESULTS

The results showed that LF levels decreased significantly from 266.53 ± 75.86 to 195.47 ± 74.53 after scaling and root planing. There was further significant reduction in LF levels to 90.42 ± 32.89 following 2 weeks of periodontal surgery, indicating decrease in inflammation.

CONCLUSION

There is a significant reduction in GCF LF levels following periodontal surgery. Hence, LF levels in GCF could serve as a useful marker for monitoring of periodontal treatment results.

Antimicrobial peptides and periodontal disease

AIMS

The goal of this review is to identify the antimicrobial proteins in the oral fluids, saliva and gingival crevicular fluid and identify functional families and candidates for antibacterial treatment.

RESULTS

Periodontal biofilms initiate a cascade of inflammatory and immune processes that lead to the destruction of gingival tissues and ultimately alveolar bone loss and tooth loss. Treatment of periodontal disease with conventional antibiotics does not appear to be effective in the absence of mechanical debridement. An alternative treatment may be found in antimicrobial peptides and proteins, which can be bactericidal and anti-inflammatory and block the inflammatory effects of bacterial toxins. The peptides have co-evolved with oral bacteria, which have not developed significant peptide resistance. Over 45 antibacterial proteins are found in human saliva and gingival crevicular fluid. The proteins and peptides belong to several different functional families and offer broad protection from invading microbes. Several antimicrobial peptides and proteins (AMPs) serve as templates for the development of therapeutic peptides and peptide mimetics, although to date none have demonstrated efficacy in human trials.

CONCLUSIONS

Existing and newly identified AMPs may be developed for therapeutic use in periodontal disease or can serve as templates for peptide and peptide mimetics with improved therapeutic indices.

Periodontitis, periodontopathic bacteria and lactoferrin

Lactoferrin (LF) is a component of saliva and is suspected to be a defense factor against oral pathogens including Streptococcus mutans and Candida albicans. Periodontitis is a very common oral disease caused by periodontopathic bacteria. Antimicrobial activities and other biological effects of LF against representative periodontopathic bacteria, Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, and Prevotella intermedia, have been widely studied. Association of polymorphisms in LF with incidence of aggressive periodontitis and the role of LF in the gingival crevicular fluid as a marker of periodontitis severity have also been reported. Periodontopathic bacteria reside as a biofilm in supragingival and subgingival plaque. Our recent study indicated that LF exhibits antibacterial activity against planktonic forms of P. gingivalis and P. intermedia at higher concentrations, and furthermore, LF effectively inhibits biofilm formation and reduces the established biofilm of these bacteria at physiological concentrations. A small-scale clinical study indicated that oral administration of bovine LF reduces P. gingivalis and P. intermedia in the subgingival plaque of chronic periodontitis patients. LF seems to be a biofilm inhibitor of periodontopathic bacteria in vitro and in vivo.

SELDI-TOF-MS of gingival crevicular fluid--a methodological approach

Human neutrophil peptides (HNPs) and the human cathelicidin LL-37 are antimicrobial peptides secreted by neutrophils, which play a crucial role in innate immune responses. The aim of this study was to establish a new method for ProteinChip arrays in combination with surface enhanced laser desorption/ionization (SELDI) technology and time-of-flight mass spectrometry to analyze gingival crevicular fluid (GCF) samples. To optimize experimental conditions, four different ProteinChip arrays (NP20; CM10, pH 4; CM10, pH 7; IMAC) along with corresponding binding buffers were tested. GCF samples were collected from patients showing healthy periodontal sites and sites with early signs of inflammation (gingivitis), but with no pocket depth greater than 4 mm. For GCF analysis, NP20 arrays and CM10 (pH 4) arrays showed specific and reproducible profiles in the range of 2.5-30.0 kDa. Donors that demonstrated significantly higher intensity peaks corresponding to the mass of LL-37 (p=0.01) also tended to show greater intensity peaks corresponding to the masses of HNP-1 and HNP-2 in samples from inflamed compared to healthy periodontal sites. The findings indicate that analysis of GCF samples by SELDI-TOF mass spectrometry is a useful approach to simultaneously analyze multiple markers, such as antimicrobial peptides, which may be beneficial for determination of new periodontal risk factors.

Inhibitory effects of lactoferrin on growth and biofilm formation of Porphyromonas gingivalis and Prevotella intermedia

Lactoferrin (LF) is an iron-binding antimicrobial protein present in saliva and gingival crevicular fluids, and it is possibly associated with host defense against oral pathogens, including periodontopathic bacteria. In the present study, we evaluated the in vitro effects of LF-related agents on the growth and biofilm formation of two periodontopathic bacteria, Porphyromonas gingivalis and Prevotella intermedia, which reside as biofilms in the subgingival plaque. The planktonic growth of P. gingivalis and P. intermedia was suppressed for up to 5 h by incubation with >or=130 microg/ml of human LF (hLF), iron-free and iron-saturated bovine LF (apo-bLF and holo-bLF, respectively), and >or=6 microg/ml of bLF-derived antimicrobial peptide lactoferricin B (LFcin B); but those effects were weak after 8 h. The biofilm formation of P. gingivalis and P. intermedia over 24 h was effectively inhibited by lower concentrations (>or=8 microg/ml) of various iron-bound forms (the apo, native, and holo forms) of bLF and hLF but not LFcin B. A preformed biofilm of P. gingivalis and P. intermedia was also reduced by incubation with various iron-bound bLFs, hLF, and LFcin B for 5 h. In an examination of the effectiveness of native bLF when it was used in combination with four antibiotics, it was found that treatment with ciprofloxacin, clarithromycin, and minocycline in combination with native bLF for 24 h reduced the amount of a preformed biofilm of P. gingivalis compared with the level of reduction achieved with each agent alone. These results demonstrate the antibiofilm activity of LF with lower iron dependency against P. gingivalis and P. intermedia and the potential usefulness of LF for the prevention and treatment of periodontal diseases and as adjunct therapy for periodontal diseases.

Association between lactoferrin gene polymorphisms and aggressive periodontitis among Taiwanese patients

BACKGROUND AND OBJECTIVE

A dramatic difference in the frequencies of the Lys/Arg single nucleotide polymorphism in the lactoferrin genotype between a small population of patients with localized juvenile periodontitis and healthy subjects has been reported. As the single nucleotide polymorphism could be associated with ethnicity, the present study aimed to investigate the association between polymorphisms of the lactoferrin gene and periodontitis.

MATERIAL AND METHODS

Sixty-five patients with aggressive periodontitis, 278 with chronic periodontitis and 88 healthy controls were genotyped for the Lys/Arg polymorphism of the lactoferrin gene at position 29 [reference sequence (rs) 1126478] in the N-terminal alpha-helical region.

RESULTS

The frequencies of the GG genotype and the G allele were highest in the aggressive periodontitis group, followed by the chronic periodontitis group and then the healthy controls. The frequency of the G allele was significantly higher in aggressive periodontitis and chronic periodontitis groups than in healthy controls (p = 0.0037 and 0.0212). Although the difference of the GG genotype distribution between subjects with chronic periodontitis and healthy controls did not reach significance, the distribution of genotypes between aggressive periodontitis and healthy controls was significantly different. The association of the gene polymorphism and aggressive periodontitis still existed, even after adjusting for age, gender and smoking status by logistic regression analysis (GG/AG+AA: odds ratio = 2.16, 95% confidence interval = 1.09-4.35, p = 0.0287). After the study, subjects were further stratified by their smoking status; the GG genotype was still significantly associated with the risk of aggressive periodontitis in the nonsmoking group (odds ratio = 2.69, p = 0.018). However, there were no statistical differences between chronic periodontitis vs. healthy controls and aggressive periodontitis vs. healthy controls in the smoking group.

CONCLUSION

The present study revealed that the A/G polymorphism in the lactoferrin gene might be associated with aggressive periodontitis. The A allele might reduce the risk of development of aggressive periodontitis in a Taiwanese population. Our results also support the hypothesis that lactoferrin genetic polymorphisms could play a role in the risk for periodontitis separate from the smoking factor. The functionality of this gene's polymorphisms has to be further elucidated.

Cleaved inflammatory lactoferrin peptides in parotid saliva of periodontitis patients

Lactoferrin (Lf) is a member of the transferrin family of iron-binding anti-bacterial proteins, present in most exocrine secretions, such as saliva, and plays an important role in mucosal defense. In this study, we identified small Lf peptides with Con A low-affinity in the parotid saliva of chronic periodontitis patients by Con A two-dimensional immunoelectrophoresis, Con A affinity chromatography and Western blotting using anti-human Lf polyclonal Ab. N-terminal amino acid sequencing of the four Con A low-affinity Lf peptides confirmed them to be fragments of intact Lf. The detection ratio of the proteinase 3 (PR3)-like activity was elevated in the parotid saliva of periodontitis patients and was associated with the severity of clinical symptoms. PR3 protein was also detected in the parotid saliva of periodontitis patients, and PR3, but not human leukocyte elastase and cathepsin G, degraded intact Lf. Con A low-affinity saliva Lf peptides showed no anti-bacterial activity against Escherichia coli, and had a reduced iron-chelating capacity. Con A low-affinity saliva Lf peptides, PR3-treated Lf preparation and two of four synthetic polypeptides induced the production of interleukin IL-6, monocyte chemoattractant protein-1 and IL-8, and the activation of NF-kappaB in human oral epithelial HSC-2 cells. Furthermore, concentrations of the Lf peptides in the parotid saliva of periodontitis patients were increased with a correlation to the severity of clinical symptoms. These results suggest that Lf in the parotid saliva of periodontitis patients was degraded into small peptides by the PR3-like activity with the capability to induce inflammatory mediators.

Gingival crevicular fluid transforming growth factor-β1 in several forms of periodontal disease

BACKGROUND

Transforming growth factor-beta(1) (TGF-beta(1)) has significant effects on periodontal host response regulation. Limited knowledge on the role of TGF-beta(1) in various periodontal disease types and particularly in advanced periodontitis forms warranted the present study. The aim of the present study was to evaluate the gingival crevicular fluid (GCF) TGF-beta(1) levels in patients with different forms of periodontal disease.

METHODS

GCF TGF-beta(1) levels were investigated in 32 chronic periodontitis (CP), 30 generalized aggressive periodontitis (G-AgP), 15 gingivitis patients and 16 periodontally healthy subjects. Periodontal status was evaluated by measuring probing depth, clinical attachment loss, plaque and bleeding on probing. TGF-beta(1) levels were analyzed by enzyme-linked immunosorbent assay. The results were expressed in terms of total amount (pg) and concentration (pg/microl).

RESULTS

G-AgP and CP groups had significantly elevated GCF TGF-beta(1) total amount compared to healthy group (p<0.008). Moreover, GCF TGF-beta(1) total amount of G-AgP group was significantly higher than that of gingivitis group (p<0.008). G-AgP and CP groups had similar GCF TGF-beta(1) total amount (p>0.008). Significant correlation was found between GCF TGF-beta(1) total amount and all clinical periodontal parameters (p<0.05).

CONCLUSIONS

The results of the present study suggest contribution of TGF-beta(1) to the pathogenesis of advanced chronic and aggressive periodontitis. TGF-beta(1) may thus be one of the components modulating exaggerated host response together with other major mediators of inflammation.

Immunolocalization of lactoferrin in healthy and inflamed gingival tissues

BACKGROUND

It has been reported that lactoferrin prevents biofilm formation and exerts antimicrobial activity. The aim of the present study was to evaluate the cellular source of lactoferrin in healthy and inflamed gingiva.

METHODS

Lactoferrin synthesis was examined in relation to disease manifestation in biopsies of the marginal gingiva by immunohistochemistry. The expression of lactoferrin in cell cultures was studied by immunocytochemistry and reverse transcription-polymerase chain reaction (RT-PCR).

RESULTS

Healthy gingiva demonstrated no immunoreactivity to lactoferrin in epithelial and connective tissue cells. In inflamed specimens, lactoferrin staining was related to inflammatory cells. These results were confirmed by cell cultures of keratinocytes that did not show any immunoreactivity against lactoferrin. No mRNA message for lactoferrin was detected by RT-PCR in keratinocytes.

CONCLUSIONS

These data provide evidence that lactoferrin is not synthesized in healthy gingival tissues. Therefore, elevated lactoferrin levels in the crevicular fluid of inflamed tissues originate from invading cells of the inflammatory reaction.

Iron and heme utilization in Porphyromonas gingivalis

Porphyromonas gingivalis is a Gram-negative anaerobic bacterium associated with the initiation and progression of adult periodontal disease. Iron is utilized by this pathogen in the form of heme and has been shown to play an essential role in its growth and virulence. Recently, considerable attention has been given to the characterization of various secreted and surface-associated proteins of P. gingivalis and their contribution to virulence. In particular, the properties of proteins involved in the uptake of iron and heme have been extensively studied. Unlike other Gram-negative bacteria, P. gingivalis does not produce siderophores. Instead it employs specific outer membrane receptors, proteases (particularly gingipains), and lipoproteins to acquire iron/heme. In this review, we will focus on the diverse mechanisms of iron and heme acquisition in P. gingivalis. Specific proteins involved in iron and heme capture will be described. In addition, we will discuss new genes for iron/heme utilization identified by nucleotide sequencing of the P. gingivalis W83 genome. Putative iron- and heme-responsive gene regulation in P. gingivalis will be discussed. We will also examine the significance of heme/hemoglobin acquisition for the virulence of this pathogen.

Lactoferrin and other markers from gingival crevicular fluid and saliva before and after periodontal treatment

OBJECTIVES

The aim of the study was to verify (i) if crevicular fluid defence variables reflect the changes after surgical periodontal treatment and (ii) if they are in correspondence with changes of these variables in the unstimulated and stimulated whole saliva.

MATERIAL AND METHODS

For 12 male and 13 female volunteers with chronic periodontitis lactoferrin concentration as well as the lysozyme and peroxidase activities were determined in crevicular fluid as well as in unstimulated and stimulated saliva before and 14 days after surgical periodontal treatment by a minimal invasive flap technique.

RESULTS

The lactoferrin concentrations decreased significantly in the crevicular fluid eluting solution from 1.63 to 1.23 mg/l reflecting a decrease in the total amount collected, in unstimulated saliva from 10.54 to 8.96 mg/l, and in stimulated saliva from 9.00 to 7.11 mg/l after treatment. No significant change could be found for lysozyme. Peroxidase activity was significantly reduced from 269.06 to 186.15 U/l only in the crevicular fluid.

CONCLUSION

The results of this study suggest that (i) the defence factor lactoferrin is suitable for monitoring of periodontal treatment results and (ii) changes of the lactoferrin concentration in crevicular fluid are related with significant changes in unstimulated and stimulated saliva.

Microbiological findings and host response in patients with peri-implantitis

The aim of the present study was to characterise microbiota and inflammatory host response around implants and teeth in patients with peri-implantitis. We included 17 partly edentulous patients with a total of 98 implants, of which 45 showed marginal bone loss of more than three fixture threads after the first year of loading. Nineteen subjects with stable marginal tissue conditions served as controls. Oral hygiene, gingival inflammation, and probing pocket depth were evaluated clinically at teeth and implants. Microbiological and crevicular fluid samples were collected from five categories of sites: 1) implants with peri-implantitis (PI), 2) stable implants (SI) in patients with both stable and peri-implantitis implants, 3) control implants (CI) in patients with stable implants alone, 4) teeth in patients (TP) and 5) controls (TC). Crevicular fluid from teeth and implants was analysed for elastase activity, lactoferrin and IL-1 beta concentrations. Elastase activity was higher at PI than at CI in controls. Lactoferrin concentration was higher at PI than at SI in patients with peri-implantitis. Higher levels of both lactoferrin and elastase activity were found at PI than at teeth in patients. The concentrations of IL-1 beta were about the same in the various sites. Microbiological DNA-probe analysis revealed a putative periodontal microflora at teeth and implants in patients and controls. Patients with peri-implantitis harboured high levels of periodontal pathogens, Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Bacteroides forsythus and Treponema denticola. These findings indicate a site-specific inflammation rather than a patient-associated specific host response.

Elastase, alpha2-macroglobulin and alkaline phosphatase in crevicular fluid from implants with and without periimplantitis

The aim of this investigation was to determine the presence of selected enzymes and enzyme inhibitors in crevicular fluid collected from implants with and without clinical, radiographic and microbiological signs of periimplantitis. Eleven implants with symptoms of periimplantitis in eight patients (four men and four women) were compared to eleven implants in seven subjects (one man and six women) without periimplantitis. Periimplant crevicular fluid (PICF) was collected at the mesial and distal sites of each implant. Alkaline phosphatase activity (ALP) was measured by using p-nitrophenyl-phosphate as substrate, elastase activity (EA) by the use of a low molecular weight fluorogenic substrate, and the inhibitor alpha2-macroglobulin (alpha2M) by ELISA. ALP, EA and alpha2M were detected in the majority of samples in both groups. In comparison to the clinically healthy implants, total amounts of each of these substances were significantly higher in PICF collected around implants with periimplantitis. The mean total amounts of EA, alpha2M and ALP in the healthy group were: EA: 1.8 ng, alpha2M: 3.1 ng, ALP: 24.1 U, and in the periimplantitis group EA: 23.1 ng, alpha2M: 25.2 ng and ALP: 142.3 U. In addition, all three mediators were correlated with the clinical parameters. The results confirm the similarity of the inflammatory response of tissues surrounding implants and natural teeth, and suggest that ALP and EA could be promising markers of bone loss around dental implants.

Levels of platelet-activating factor in gingival crevicular fluid and gingival tissue in specific periodontal diseases

BACKGROUND

Platelet-activating factor (PAF), a potent phospholipid mediator of inflammatory and immune reactions, is involved in a variety of biological responses seen in periodontal diseases. The aim of the present study was to examine the role of PAF in the pathogenesis of specific periodontal diseases.

METHODS

PAF levels were investigated in gingival crevicular fluid (GCF) and gingival tissue (GT) samples of 12 patients with generalized aggressive periodontitis (GAgP), 6 patients with localized aggressive periodontitis (LAgP), 10 patients with chronic periodontitis (CP), 6 with gingivitis (G), and 6 periodontally healthy subjects (H). Periodontal status was evaluated by measuring probing depth, gingival index, papillary bleeding index, and plaque index. PAF was extracted from GCF samples passing through amberlit resin columns, purified by high performance liquid chromatographic method, and then analyzed by radioimmunoassay.

RESULTS

GAgP, LAgP, and CP groups had significantly higher GCF PAF levels compared to the H group (P<0.005). Although statistically not significant, GCF PAF levels were also higher in the G group than those of the H group (P = 0.0784). GAgP, LAgP, and CP groups had similar GCF PAF levels (P>0.005). These groups had higher levels of GCF PAF than those of the G group, but the difference was significant only for the GAgP group (P<0.005). When the data were expressed as concentration, GAgP, LAgP, and CP groups were found to have higher concentrations of GCF PAF compared to the H group (P<0.005). GCF PAF concentration was similar in patient groups (P>0.005). All patient groups had significantly higher GT PAF levels compared to the H group (P<0.005). GAgP, LAgP, and CP groups had similar amounts of GCF and GT PAF (P>0.005). GAgP, LAgP, and CP groups had higher GT PAF levels than those of the G group, but the differences were only significant for LAgP and CP groups (P<0.005). No significant correlation was found between GCF and GT PAF levels and clinical parameters.

CONCLUSIONS

The results of the present study indicate that PAF is likely to be an important mediator in regulating inflammatory responses in the human periodontal tissues. To our knowledge, this is the first report investigating PAF levels in GCF and GT in specific periodontal diseases. We believe that this potent phospholipid mediator may need to be considered in the pathogenesis of periodontal diseases.

Levels of leukotriene B4 in gingival crevicular fluid and gingival tissue in specific periodontal diseases

BACKGROUND

Leukotriene B4 (LTB4), a product of the lipoxygenase pathway of arachidonic acid metabolism, exhibits numerous activities that can account for most of the features of host responses seen in periodontal diseases. The aim of the present study was to examine the role of LTB4 in the pathogenesis of specific periodontal diseases.

METHODS

LTB4 levels were investigated in gingival crevicular fluid (GCF) and gingival tissue (GT) samples of 10 patients with chronic periodontitis (CP), 12 patients with generalized aggressive periodontitis (GAgP), 6 patients with localized aggressive periodontitis (LAgP), 6 patients with gingivitis (G), and 6 periodontally healthy subjects (H). Periodontal status was evaluated by measuring probing depth, gingival index, papillary bleeding index, and plaque index. LTB4 was extracted from the samples by solid-phase method using C18 cartridge and was purified by high performance liquid chromatographic method and then analyzed by radioimmunoassay.

RESULTS

All patient groups had significantly higher levels of GCF and GT LTB4 compared to the control group (P<0.005). The CP patients had the highest LTB4 levels compared to those in other patient groups (P<0.005). GAgP, LAgP, and G groups had similar amounts of GCF and GT LTB4 (P>0.005). When the data were expressed as concentration, the CP group was found to have higher concentration of LTB4, compared to that of control group (P<0.005). GAgP, LAgP, and G groups had similar LTB4 concentration compared to that of control group (P>0.005). No significant difference was found between GAgP, LAgP, and G groups (P>0.005). The CP group had higher LTB4 concentration compared to both GAgP and LAgP groups (P<0.005). Although the CP group had a higher GCF LTB4 concentration compared to G group, this difference did not reach significance (P>0.005). No significant correlation was found between GCF and GT LTB4 levels and clinical parameters.

CONCLUSIONS

The results of the present study indicate that LTB4 is likely to be an important mediator in regulating inflammatory responses in the human periodontal tissues. This lipid mediator may play an important role in the pathophysiology of periodontal disease.

Human lactoferrin binds and removes the hemoglobin receptor protein of the periodontopathogen Porphyromonas gingivalis

Porphyromonas gingivalis possesses a hemoglobin receptor (HbR) protein on the cell surface as one of the major components of the hemoglobin utilization system in this periodontopathogenic bacterium. HbR is intragenically encoded by the genes of an arginine-specific cysteine proteinase (rgpA), lysine-specific cysteine proteinase (kgp), and a hemagglutinin (hagA). Here, we have demonstrated that human lactoferrin as well as hemoglobin have the abilities to bind purified HbR and the cell surface of P. gingivalis through HbR. The interaction of lactoferrin with HbR led to the release of HbR from the cell surface of P. gingivalis. This lactoferrin-mediated HbR release was inhibited by the cysteine proteinase inhibitors effective to the cysteine proteinases of P. gingivalis. P. gingivalis could not utilize lactoferrin for its growth as an iron source and, in contrast, lactoferrin inhibited the growth of the bacterium in a rich medium containing hemoglobin as the sole iron source. Lactoferricin B, a 25-amino acid-long peptide located at the N-lobe of bovine lactoferrin, caused the same effects on P. gingivalis cells as human lactoferrin, indicating that the effects of lactoferrin might be attributable to the lactoferricin region. These results suggest that lactoferrin has a bacteriostatic action on P. gingivalis by binding HbR, removing it from the cell surface, and consequently disrupting the iron uptake system from hemoglobin.

Neutrophil migration into the gingival sulcus is associated with transepithelial gradients of interleukin-8 and ICAM-1

The expression of adhesion molecules and the local production of chemotactic cytokines within the epithelium are considered to be key events in neutrophil (PMN) migration at sites of mucosal infections. In their journey toward the gingival sulcus, PMNs have been shown to selectively migrate through the junctional epithelium. Little, however, is known about the molecular mechanisms involved in this key process aimed at the control of subgingival bacterial plaque. This investigation describes the expression of IL-8 mRNA-positive cells and the establishment of a gradient of intercellular adhesion molecule-1 (ICAM-1) receptors within the junctional epithelium of clinically healthy gingiva. Expression of ICAM-1 and IL-8 was topographically associated with the area of PMN migration; i.e., the junctional epithelium. Levels of ICAM-1 expression increased from the basal cells toward the surface of the junctional epithelium and thus toward areas exposed to bacterial challenges. IL-8 mRNA-positive cells were also present at highest density in the most superficial junctional epithelial layers. The combination of the haptotactic stimuli, resulting from the interaction of the PMN's beta2 integrin receptors with the gradient of ICAM-1 expression, and the location of IL-8 mRNA-positive cells, consistent with the establishment of a discrete PMN chemotactic source, may play an important physiologic role in efficiently routing PMNs to the gingival sulcus. This process contributes to the maintenance of a local host-parasite equilibrium and to the limitation of PMN-associated tissue damage.

Evaluation of the antimicrobial effect of lactoferrin on Porphyromonas gingivalis, Prevotella intermedia and Prevotella nigrescens

The antimicrobial effect of lactoferrin (apoLf) on the oral, black-pigmented anaerobes Porphyromonas gingivalis, Prevotella intermedia and P. nitrescens has been studied. ApoLf did not kill any of these species but it did inhibit the growth of P. gingivalis, while iron-saturated Lf (FeLf) had no effect. The other two species were unaffected by apoLf. This growth inhibitory effect of apoLf could not be explained on the basis of chelation of inorganic iron, since growth of P. gingivalis occurred in the presence of ethylenediamine di-o-hydroxyphenylacetic acid provided haemin was added. Both apoLf and FeLf reduced haemin uptake by all three species and caused the release of cell-bound haemin in a dose-dependent manner. In addition, haemin reduced the binding of both apoLf and FeLf to P. intermedia and P. nigrescens but stimulated the binding of Lf by P. gingivalis. These data suggest that Lf forms complexes with haemin in solution and competes for the binding of haemin to certain cell receptors, possibly lipopolysaccharides, but this is not sufficient to inhibit growth of the bacteria. P. gingivalis appears to bind Lf-haemin complexes, as well as haemin alone, which may facilitate access of the Lf to the outer and cytoplasmic membranes of P. gingivalis, so disrupting function.

Lactoferrin impedes epithelial cell adhesion in vitro

In the process of host defence against microbial challenge, neutrophils release granule contents with the potential side effect of damaging structural tissues. In the junctional epithelium such damage may contribute to the degeneration and renewal of the epithelial cells attached directly to the tooth (DAT cells), and subsequently to periodontal pocket formation. This study reports on lactoferrin, one of the substances released by neutrophils, and its effects on epithelial cell adhesion, growth, DNA synthesis and spreading of cell colonies at concentrations recorded in the crevicular fluid. We show that, in opposition to what has been reported on bacterial cells, lactoferrin has no effect on the DNA synthesis of attached epithelial cells in model systems attempting to simulate the DAT cells in vivo. However, both iron-saturated and unsaturated lactoferrin hampered cell adhesion, growth and spreading of cell colonies in a dose-dependent manner. These findings suggest that lactoferrin does not affect epithelial cell proliferation but it may have a role in delaying the repair of the DAT cell population during inflammation by interfering with cell adhesion.

Effect of an encapsulated anti-elastase compound on experimental gingival inflammation in the rat

An animal (rat) model of gingival injury ("impaction") induced a gingival inflammatory reaction, which was characterized by a breakdown of gingival collagen and the elastic network, as well as a significant increase of gingival elastase. The present study was conducted to investigate whether ceramides, sphingolipids composed of sphingosine N-acyl-linked to fatty acids, a chemical structure with antielastase properties, could counteract the development of such an inflammatory process. The ceramides used in these experimental series were extracted from wheat and characterized. The main fatty acids were 16:0, 18:1, 18:2, and the sphingoid moiety was phytosphingosine. Inhibition of elastase by ceramides was demonstrated in vitro and the concentration necessary to inhibit 50% of elastase activity was 41 mg/l using the synthetic substrate methoxysuccinyl-alanine-alanine-proline-valine-p-nitroanilide (MeOSuc-AlaAlaProValpNA). However, this anti-elastase activity was not observed in vivo in our animal model of gingival inflammation. A glycosaminoglycan (Heparin), recognized as a potent inhibitor of elastase, was entrapped in ceramides. A local treatment of impacted gingivae by encapsulated heparin led to a dose-related decrease of the elastase level in gingival extracts. Encapsulation in ceramides potentiated the effect exerted by heparin alone. This inhibitory effect of encapsulated heparin on elastase suggested a vector effect of these amphipathic molecules.

Markers of inflammation in crevicular fluid from peri-implant mucosa surrounding single crystal sapphire implants

The 19 patients included in this study had all been successfully treated for total or partial edentulism with single crystal sapphire implants as retention for overdentures or fixed bridges. As there is a need for more reliable non-invasive parameters for detecting changes surrounding endosseous implants, the aim of this study was to assess the content and the activity of neutrophils in crevicular fluid samples from 3 categories of sites: (1) crevices around implants from edentulous patients (2) crevices around implants in partially edentulous patients, and (3) crevices surrounding teeth. Fluid samples were taken with paper strips from 9 partially edentulous and 10 edentulous patients and the volume measured with a Periotron 6000. Elastase activity was measured as a marker of neutrophil activity and lactoferrin concentration as a marker of the number of neutrophils. Elastase activity per microliter and lactoferrin concentration was, despite similar clinical and radiographic signs, significantly higher in samples from crevices surrounding teeth and implants in the partially edentulous patients compared to samples from crevices around implants in the totally edentulous patients. There were no differences between teeth and implants in partially edentulous patients. The increased elastase activity and lactoferrin concentration indicates a higher neutrophil activity in patients with remaining teeth.

Degradation of lactoferrin by periodontitis-associated bacteria

The degradation of human lactoferrin by putative periodontopathogenic bacteria was examined. Fragments of lactoferrin were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and measured by densitometry. The degradation of lactoferrin was more extensive by Porphyromonas gingivalis and Capnocytophaga sputigena, slow by Capnocytophaga ochracea, Actinobacillus actinomycetemcomitans and Prevotella intermedia, and very slow or absent by Prevotella nigrescens, Campylobacter rectus, Campylobacter sputorum, Fusobacterium nucleatum ssp. nucleatum, Capnocytophaga gingivalis, Bacteroides forsythus and Peptostreptococcus micros. All strains of P. gingivalis tested degraded lactoferrin. The degradation was sensitive to protease inhibitors, cystatin C and albumin. The degradation by C. sputigena was not affected by the protease inhibitors and the detected lactoferrin fragments exhibited electrophoretic mobilities similar to those ascribed to deglycosylated forms of lactoferrin. Furthermore a weak or absent reactivity of these fragments with sialic acid-specific lectin suggested that they are desialylated. The present data indicate that certain bacteria colonizing the periodontal pocket can degrade lactoferrin. The presence of other human proteins as specific inhibitors and/or as substrate competitors may counteract this degradation process.

Matrix metalloproteinases and their inhibitors in gingival crevicular fluid and saliva of periodontitis patients

Matrix metalloproteinases (MMPs) and serine proteinases seem to be related to tissue destruction in periodontitis. The presence of MMPs in gingival crevicular fluid (GCF) and saliva, however, has not been studied comprehensively with the enzyme-linked immunosorbent assay (ELISA)-technique. We therefore examined the levels of MMP-1, -3, -8 and -9, and their endogenous inhibitor, tissue inhibitor of matrix metalloproteinases (TIMP-1), in GCF and saliva of patients with adult periodontitis (AP) and localized juvenile periodontitis (LJP). Elevated levels of MMP-1 were detected in LJP GCF compared to AP and control GCF. Elevated levels of TIMP-1 were also detected in LJP GCF in comparison to AP and control GCF. Higher MMP-8 levels were detected in AP GCF compared to LJP and control GCF. The relative low levels of MMP-3 were present in all studied GCF samples. Elevated levels of MMP-8 were further detected in saliva of AP compared to LJP and the controls. Both MMP-1 and TIMP-1 were detected in all studied saliva samples, but not significant differences were detected between the studied groups. Our ELISA-results confirm that (i) PMN MMP-8 and MMP-9 are the main collagenase and gelatinase in AP GCF, whereas GCF collagenase in LJP seems to be of the MMP-1-type; (ii) only low levels of TIMP-1, endogenous MMP-inhibitor, are present in AP GCF, which emphasises the importance of doxycycline as a possible adjunctive drug in the treatment of AP patients; (iii) tests based on specific antibodies against PMN MMPs, especially MMP-8, might serve as a reliable method of measuring and monitoring enzyme levels in GCF from different periodontitis patients.

Laminin binding to a heat-modifiable outer membrane protein of Actinobacillus actinomycetemcomitans

The interaction of Actinoabacillus actinomycetemcomitans with the basement membrane protein, laminin, was examined in a 125I-labeled protein-binding assay. The binding of laminin increased by lowering the pH. The ability to bind laminin was decreased in cells at the stationary phase of growth and by the presence of blood in the culture medium. Laminin binding to this bacterium was saturable, and the affinity constant was 4.6 nM. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis and Western blot (ligand blot) analysis of cell-envelope and outer membrane of A. actinomycetemcomitans displayed a 125I-laminin-reactive protein band with a molecular weight of 29 k. The laminin-binding protein was the previously described outer membrane protein A of A. actinomycetemcomitans. It was identified by its heat-modifiable property, detergent-solubility profile and reactivity with outer membrane protein A-specific polyclonal antiserum. At acidic pH, 25I laminin bound to several cell-envelope components of A. actinomycetemcomitans, but at neutral pH, laminin bound only to the heat-modifiable protein. Despite the existence of the laminin-binding protein, cells grown in blood-containing media did not bind laminin. Several mammalian proteins interfered with laminin-bacterial interaction, including lactoferrin, which binds to the same bacterial protein that inhibited and displaced the laminin-bacterial interaction.

Peroxidases, lactoferrin and lysozyme in peripheral blood neutrophils, gingival crevicular fluid and whole saliva of patients with localized juvenile periodontitis

OBJECTIVE

The aim of this study was to examine the longitudinal association of selected non-immune anti-microbial host factors (peroxidases, lysozyme and lactoferrin) to the localized juvenile periodontitis (LJP) disease status.

MATERIALS AND METHODS

Peroxidases, lysozyme and lactoferrin were quantitated from seven patients with LJP before and after periodontal therapy. Analyses were performed from simultaneously collected samples of peripheral blood polymorphonuclear leukocytes (PMNs), gingival crevicular fluid (GCF from diseased sites) and paraffin-stimulated whole saliva. Similar assays were done also from seven periodontally healthy controls.

RESULTS

During untreated phase of LJP myeloperoxidase, lysozyme and lactoferrin concentrations were remarkably elevated in peripheral blood PMNs, also reflected in their high concentrations in GCF. All these values normalised with respect to healthy controls during the periodontal therapy. No similar longitudinal changes were seen in whole saliva but during therapy salivary peroxidase concentrations declined below the control values, in accordance with our previous observations in parotid saliva samples of LJP patients.

CONCLUSIONS

In LJP the concentrations of lysozyme, lactoferrin and myeloperoxidase are significantly elevated in peripheral blood PMNs, also reflected in GCF. During periodontal therapy these values decline and approach those observed in healthy controls. No similar changes are seen in stimulated whole saliva.

Effect of localized experimental gingivitis on early supragingival plaque accumulation

Previous investigations have reported increased plaque formation in the presence of gingival inflammation as compared with gingival health. In these investigations, experimental gingivitis has been induced by total abolition of oral hygiene such that increased levels of salivary bacteria could contribute to the increased plaque formation. In the present study, experimental gingivitis was localized to 2 selected teeth whilst maintaining normal oral hygiene measures in the rest of the mouth. The aim of this study was to investigate whether the mass of plaque accumulating in a 3-day period is influenced by the inflammatory status of the adjacent gingival margins. Following scaling, prophylaxis and a period of optimal hygiene to establish gingival health, "plaque-guards" were worn during routine oral hygiene performance to prevent any cleaning on the buccal surfaces of teeth 14 and 15 from days 0 to 3. On day 3, accumulated plaque was removed from a 1.5 mm zone on the buccal surfaces of 14 and 15 adjacent to the gingival margins and weighed immediately. Subjects continued to wear their plaque-guards during oral hygiene until day 14 to induce experimental gingivitis around the experimental teeth. At day 14, all plaque was cleaned from the buccal surfaces of the experimental teeth and the mass of plaque accumulating over the next 3 days weighed on day 17. Comparison of plaque weights showed that the wet-weight of 3 day-old plaque was higher in the presence of experimental gingivitis than in the presence of gingival health (p = 0.02). This observation suggests that the inflammatory status of the marginal gingiva has an important effect on early, supragingival plaque accumulation.

Cathepsin G in gingival tissue and crevicular fluid in adult periodontitis

The presence, localization and activities of cathepsin G in gingival tissue specimens and crevicular fluid (GCF) from 9 adult periodontitis patients and 6 controls with clinically healthy periodontium were studied by use of avidinbiotin-peroxidase complex method, Western and dot blotting, and spectrophotometric activity assay. In contrast to healthy gingival tissue specimens, gingival tissue specimens collected from adult periodontitis patients contained inflammatory cells in lamina propria, beneath the oral sulcular epithelium, 10-50% of which were cathepsin G positive polymorphonuclear neutrophilic leukocytes (PMNs) and monocyte/macrophage-like cells. Cathepsin G activities were increased in adult periodontitis GCF when compared to periodontally healthy controls' GCF (p < 0.05). In adult periodontitis GCF, Western blotting disclosed free cathepsin G but also clear complexes of cathepsin G with its predominant endogenous inhibitor alpha 1-antichymotrypsin (alpha 1-ACT). The present results demonstrate that part of the cathepsin G, despite the presence of increased concentrations of alpha 1-ACT, was in an uncomplexed, free and functionally active form. Our results suggest that GCF cathepsin G reflects the disease process in adjacent inflamed gingiva and also increased host response to microbiota and/or dental plaque in the periodontitis lesions. Cathepsin G may contribute to periodontal tissue destruction directly and indirectly, via proteolytic activation of latent neutrophil procollagenase (promatrix metalloproteinase-8 [proMMP-8]).

Effects of treatment on gingival crevicular collagenase, stromelysin and tissue inhibitor of metalloproteinases and their ability to predict response to treatment

Fibroblast collagenase (FIB-CL) and stromelysin (SL) are members of a family of enzymes which are capable of degrading most of the extracellular matrix macromolecules. Extracellular control of these enzymes is performed by tissue inhibitor of metalloproteinases (TIMP). During healing, inflammation and normal tissue turnover, levels of MMPs and TIMP will change. The effect of treatment on the levels of FIB-CL, SL and TIMP as well as their ability, at baseline, to predict the outcome of therapy was investigated. 21 patients each provided 8 gingival crevicular fluid (GCF) samples from sites with probing depths > or = 4 mm. Clinical recordings and GCF sampling were performed at 3 time points. Assays for SL, FIB-CL and TIMP were performed by a sandwich ELISA. Attachment level changes were detected by the "tolerance method". The ability of the GCF constituents to predict the response to treatment was assessed by comparing pre-treatment levels between sites which did or did not show attachment gain after therapy. Although no GCF constituents could reliably predict the response to treatment, SL reduced significantly (p = 0.029) after the hygiene phase of therapy. In addition, both SL and TIMP levels showed a highly significant reduction at follow-up visit (p = 0.003 and p = 0.005 respectively). Thus, SL and TIMP levels are reduced by treatment, but these GCF proteins do not appear to have an ability to predict treatment outcome from baseline.

Detection of stable and active periodontitis sites by clinical assessment and gingival crevicular acute-phase protein levels

The aim of the present study was to investigate whether incipient periodontal disease breakdown could be associated with changes in gingival crevicular fluid (GCF) acute-phase protein levels. In addition, the potential of clinical indices to act as predictors of significant attachment level (AL) change was investigated. AL measurements were taken at baseline and 3 months using the Florida Probe stent handpiece from a total of 384 sites in 38 patients. The average standard deviation of duplicate AL measurements was 0.423. When the tolerance method was used to detect significant AL change, 3.9% of the sites lost attachment. When a less stringent criterion of AL change of > or = 1 mm was used 9.9% of the sites lost attachment during the 3-month period. With the exception of probing depth, baseline clinical parameters failed to predict AL change. Fourteen active periodontitis sites that demonstrated significant attachment loss were paired to stable periodontitis sites within the same patient. The levels of four acute-phase proteins, namely alpha 2-macroglobulin (alpha 2-M), alpha 1-antitrypsin (alpha 1-AT), transferrin (TF) and lactoferrin (LF), and also albumin (Alb) were assessed in the same gingival crevicular fluid sample using sandwich ELISAs. Results were expressed either as ng/30 s and ng/microgram Alb. Acute-phase protein levels in GCF failed to differentiate between active and stable periodontitis sites at baseline. In conclusion, the degree of gingival inflammation of the tissues adjacent to the crevice/pocket seems to influence the levels of protease inhibitors and iron-binding proteins in GCF to a greater extent than probing attachment loss.

Oral fluid elastase as an indicator of periodontal health

The study was designed to find out whether oral elastase activity could be used as a simple biochemical indicator of periodontal health. Both stimulated whole saliva and water rinse samples were collected from subjects with different degrees of adult periodontitis, gingivitis or healthy periodontium. In both sample types, elastase was mostly bound to insoluble fraction and preferred valine containing synthetic substrate, similar to neutrophil elastase. The elastase measurement required very little manipulation or time and its reproducibility was found to be good. The elastase levels were found to be negligible in edentulous subjects and usually very low in subjects with healthy periodontium. In about 85% of periodontitis cases having at least 1 deep periodontal pocket ( > or = 6 mm), clearly elevated elastases levels were detected in both the saliva and r rinse samples. In advanced periodontitis cases, the colour reaction took place in 0.5 to 2 h. In localized periodontitis cases, 2- to 18-h incubations were required for positive reaction. There was a good correlation between the elastase activity and the number of deep periodontal pockets and the average community periodontal index of the subjects. Elastase activity was not a good indicator of gingivitis. About 45% of gingivitis cases were positive with the elastase test, and the enzyme values were not significantly increased in experimental gingivitis. In a longitudinal study on advanced periodontitis cases, elastase levels dropped dramatically as a result of clinically successful therapy, close to the values of healthy subjects. The oral elastase test could serve as a valuable adjunct in periodontal screening and assessment of treatment efficacy.

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.

Detection of interleukin-1 beta mRNA-expressing cells in human gingival crevicular fluid by in situ hybridization

Interleukin-1 beta (IL-1 beta) mRNA-expressing cells in human gingival crevicular washings (GCW) obtained from patients with periodontitis and healthy controls were examined by in situ hybridization. GCW was done at 15 diseased sites [Gingival Index > 1; pocket depth > or = 5 mm] from five patients with adult periodontitis and eight clinically periodontal healthy sites from three volunteers GI < or = 1; PD < or = 3 mm), and then the samples were cytocentrifuged. In situ hybridization using digoxigenin-labelled oligonucleotide probe complementary to human IL-1 beta mRNA showed IL-1 transcripts in both polymorphonuclear leucocytes and mononuclear cells but not in epithelial cells in all GCW samples from diseased and healthy sites. Polymorphs were the predominant leucocytes in diseased and healthy sites, averaging 91.7 +/- 4.6 and 77.0 +/- 10.3%, respectively. The percentages of IL-1 beta mRNA-positive polymorphonuclear leucocytes in GCW samples from diseased and healthy sites were 92.3 +/- 4.7 and 80.9 +/- 10.3%, respectively. The IL-1 beta gene signals in individual cells were quantified in five samples (two healthy and three diseased sites). The mean amounts of IL-1 beta mRNA expression in polymorphonuclear leucocytes was higher than that of mononuclear cells in all samples and there was heterogeneity within the populations of polymorphonuclear and mononuclears cells in their ability to express the IL-1 beta gene. These findings indicate that IL-1 beta may be predominantly produced by polymorphonuclear leucocytes in the gingival crevice of patients with adult periodontitis and periodontally healthy controls.

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.

Gingival crevicular stromelysin, collagenase and tissue inhibitor of metalloproteinases levels in healthy and diseased sites

The ability of stromelysin (SL), fibroblast-type collagenase (FIB-CL) and tissue inhibitor of metalloproteinases (TIMP), to differentiate between healthy, gingivitis and periodontitis sites was investigated. SL and FIB-CL are members of a family of enzymes which are capable of degrading most of the extracellular matrix macromolecules. Extracellular control of these enzymes is performed by TIMP. 40 patients each provided 3 GCF samples from healthy, gingivitis and periodontitis sites. GCF samples were collected by means of sterile paper strips. GCF samples were eluted into 500 microliters of assay buffer and assays for SL, FIB-CL and TIMP were performed by a sandwich ELISA. The mean amounts of SL and TIMP in diseased sites (gingivitis and periodontitis) were significantly higher than the mean amount of these GCF components in healthy sites (MANOVA p values were: 0.006 for SL and 0.001 for TIMP). GCF SL and TIMP differentiated healthy from diseased sites. Both SL and TIMP showed moderate correlation with clinical indices. FIB-CL was detectable in only 20.8% of all sites and did not correlate with disease status.

Lactoferrin interaction with Actinobacillus actinomycetemcomitans

The interaction of lactoferrin with Actinobacillus actinomycetemcomitans was examined in a 125I-labeled protein binding assay. The binding of human and bovine lactoferrins reached maximum within 1 h. Lactoferrin binding to the bacterium was pH-dependent and reversible. Scatchard analysis indicated the existence of two different types of binding sites on the bacterium, one with a high affinity constant k alpha approximately 8.8 x 10(-7) M) and the other with a low one (k alpha approximately 1.8 x 10(-6) M). Bacteria in the exponential phase of growth showed higher binding than cells in the stationary phase. Bacteria grown in medium containing serum and/or lysed erythrocytes bound lactoferrin to a lesser extent. Heat-inactivated serum, lysed erythrocytes and other proteins such as mucin and laminin inhibited lactoferrin binding to A. actinomycetemcomitans in a competitive binding assay. Sodium dodecyl sulfate polyacrylamide-gel electrophoresis and Western blot analysis of the cell envelope as well as the outer membrane of A. actinomycetemcomitans revealed lactoferrin-reactive protein bands at 29 kDa and 16.5 kDa. The 29-kDa band displayed a heat-modifiable lactoferrin-reactive form with a molecular weight of 34 kDa. Neither proteinase K-treated cell envelope nor lipopolysaccharide of this bacterium showed reactivity with lactoferrin. These data suggests a specific interaction of lactoferrin with outer membrane proteins of A. actinomycetemcomitans.

The recovery efficiency of various materials for sampling enzymes and polymorphonuclear leukocytes from gingival crevices

The present investigation was designed to assess the effects of strips made of different materials on the recovery of enzymes in gingival crevicular fluid (GCF) (Experiment 1), and to examine a possible relationship between lysosomal enzyme activities and number of crevicular polymorphonuclear leukocytes (PMNs) (Experiment 2). In Experiment 1, GCF was collected with capillaries from 14 patients with periodontal disease, and applied on various test strips in microcentrifuged tubes or directly into tubes (controls). Strips were then shaken and centrifuged to elute GCF enzymes. The supernate was used for determinations of alkaline phosphatase (ALP), beta-glucuronidase (BG) and aspartate aminotransferase (AST) activities. The % recoveries were calculated as relative percentages to controls. When using saline as eluent, 90% or more ALP, BG and AST were found to be recovered from strips of durapore and papers. More than 35% of ALP and BG was found to remain on paper points. However, the % recoveries from paper points were improved using eluent with 0.1% (w/v) cetyl pyridinium chloride. In Experiment 2, 54 GCF samples were collected from 3 periodontitis patients by using durapore strips, in order to measure both PMN numbers and BG activities in the same samples. The 2 parameters showed strong and positive correlation with 0.847 (p < 0.001) of the Pearson's correlation coefficient. These findings suggest that durapore is a useful material not only for counting PMNs but also for measuring activities of GCF enzymes. Elevation of BG activities in GCF can be due to increasing numbers of PMNs.