Active and alpha-1 proteinase inhibitor complexed leukocyte elastase levels in crevicular fluid from patients with periodontal diseases

Gingipains of Porphyromonas gingivalis Affect the Stability and Function of Serine Protease Inhibitor of Kazal-type 6 (SPINK6), a Tissue Inhibitor of Human Kallikreins

Periodontitis, a chronic inflammation driven by dysbiotic subgingival bacterial flora, is linked on clinical levels to the development of a number of systemic diseases and to the development of oral and gastric tract tumors. A key pathogen, Porphyromonas gingivalis, secretes gingipains, cysteine proteases implicated as the main factors in the development of periodontitis. Here we hypothesize that gingipains may be linked to systemic pathologies through the deregulation of kallikrein-like proteinase (KLK) family members. KLKs are implicated in cancer development and are clinically utilized as tumor progression markers. In tissues, KLK activity is strictly controlled by a limited number of tissue-specific inhibitors, including SPINK6, an inhibitor of these proteases in skin and oral epithelium. Here we identify gingipains as the only P. gingivalis proteases responsible for SPINK6 degradation. We further show that gingipains, even at low nanomolar concentrations, cleaved SPINK6 in concentration- and time-dependent manner. The proteolysis was accompanied by loss of inhibition against KLK13. We also mapped the cleavage by Arg-specific gingipains to the reactive site loop of the SPINK6 inhibitor. Moreover, we identified a significant fraction of SPINK6-sensitive proteases in healthy saliva and confirmed the ability of gingipains to inactivate SPINK6 under ex vivo conditions. Finally, we demonstrate the double-edge action of gingipains, which, in addition, can activate KLKs because of gingipain K-mediated proteolytic processing of the zymogenic proform of KLK13. Altogether, the results indicate the potential of P. gingivalis to disrupt the control system of KLKs, providing a possible mechanistic link between periodontal disease and tumor development.

Smoking affects diagnostic salivary periodontal disease biomarker levels in adolescents

BACKGROUND

The effects of smoking on periodontal biomarkers in adolescents are unknown. This study investigates matrix metalloproteinase (MMP)-8 and polymorphonuclear leukocyte elastase levels in saliva together with periodontal health indices accounting for body mass index and smoking in a birth cohort from Finland.

METHODS

The oral health of boys (n = 258) and girls (n = 243) aged 15 to 16 years was examined clinically. Health habits were assessed by questionnaire. Saliva samples were collected and analyzed by immunofluorometric and peptide assays for MMP-8 levels and polymorphonuclear leukocyte elastase activities, and investigated statistically with the background factors.

RESULTS

Median MMP-8 values of male smokers were 112.03 microg/l compared to 176.89 microg/l of non-smokers (P = 0.05). For female smokers corresponding values were 170.88 microg/l versus 177.92 microg/l in non-smokers (not statistically significant). Elastase values in male smokers were 5.88 x 10(-3) Delta OD(405)/h versus 11.0 x 10(-3) Delta OD(405)/h in non-smokers (P = 0.02), and in female smokers 9.16 x 10(-3) Delta OD(405)/h versus 10.88 x 10(-3) Delta OD(405)/h in non-smokers (P = 0.72). The effect was strengthened by high pack-years of smoking (MMP-8, P = 0.04; elastase, P = 0.01). Both biomarkers increased with gingival bleeding. However, statistically significant associations were observed with bleeding on probing and MMP-8 (P = 0.04); MMP-8 was suggestively associated with probing depth (P = 0.09) in non-smoking boys. In smokers with calculus, MMP-8 increased after adjusting with body mass index (P = 0.03). No corresponding differences were seen in girls.

CONCLUSIONS

Smoking significantly decreased both biomarkers studied. Compared to girls, boys seem to have enhanced susceptibility for periodontitis as reflected in salivary MMP-8 values.

Elastolysis induces collagenolysis in a gingival lamina propria model

Elastin peptides were previously reported to increase MMP expression in several cell types. We found binding of these peptides to their receptors led to enhanced MMP-3 and MMP-1 expression, but not activation, in human gingival fibroblasts cultured on plastic dishes. We hypothesized that these peptides, in a more physiological environment, might additionally trigger an MMP-3/MMP-1 activation cascade, leading to matrix lysis, as occurs in periodontitis. To test this hypothesis, we used contracted and attached lattices as gingival lamina propria equivalents. In such 3D models, supplementation of elastin peptides and plasminogen triggered an MMP-3/MMP-1 activation cascade and significant down-regulation of TIMPs production, further leading to intense collagen degradation. We propose that elastolysis, as occurs in periodontitis, potentiates collagenolysis, thus promoting disease progression.

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.

Advances in periodontal disease markers

A computer-assisted medline search was conducted to find the relevant articles concerning the periodontal disease markers in gingival crevicular fluid (GCF) and saliva published during the 10-year period from 1993 to July 2003. This review suggests that certain diagnostic uses of saliva and GCF show promise. Although both fluids have been used to evaluate the risk for an individual to develop periodontal disease and to monitor of the host response to periodontal therapy, GCF has the chance of being closely approximated to the periodontal tissues where periodontal disease begins. The enzymes contributed to extracellular matrix (ECM) molecules and non-ECM molecules degradation and markers for polymorphonuclear leukocytes (PMN) activity and influx into the gingival tissue seem to provide valuable information regarding the periodontal disease diagnosis and prognosis. There is also an increasing evidence implicating reactive oxygen species and nitric oxide pathway in the pathogenesis of periodontal diseases. Although promising results have been achieved with the assays evaluating the markers in assessment of periodontal disease status, up to now, none of these tests are used routinely. Further, one commercially available genetic test has been reported to have the potential to be used to predict the periodontal disease, but there are controversial reports on this genetic susceptibility test.

Position Paper: Diagnosis of Periodontal Diseases

At the present time, the diagnosis and classification of periodontal diseases are almost entirely based on traditional clinical assessments. Supplemental quantitative and qualitative assessments of the gingival crevicular fluid and subgingival microflora can potentially provide useful information about the patient's periodontal disease. In certain situations, these supplemental risk-assessment tests may be particularly valuable in establishing the endpoint of therapy prior to placing patients on a periodontal maintenance program. Although the clinical utility of none of these tests has been validated, their further development is warranted. A genetic test for susceptibility to periodontitis has become commercially available. How best to use this and future host-based tests in clinical practice remains to be determined. Probing depth and clinical attachment loss measurements obtained with periodontal probes are practical and valid methods for assessing periodontal status. Computer-linked, controlled-force electronic periodontal probes are commercially available and are currently in use by some practitioners. Many of the logistical problems associated with subtraction radiography are being overcome and this powerful diagnostic tool may soon come into widespread use. Future developments in this and other imaging techniques are likely to have a profound effect on our approach to the diagnosis of periodontal diseases.

Amplified crevicular leukocyte activity in aggressive periodontal disease

Exaggerated neutrophil responses are a critical component in the pathogenesis of periodontal disease. We investigated whether leukocyte activity in aggressive periodontitis (AP) is increased compared with that in chronic periodontitis (CP) by gingival crevicular fluid (GCF) analysis of myeloperoxidase (MPO), beta-N-acetyl-hexosaminidase (beta-NAH), cathepsin D (CD), and elastase-alpha-1-proteinase inhibitor complex (alpha-1-EPI) before and 6 months after therapy. Initial AP neutrophil responses were significantly amplified compared with those in CP (MPO, 3.2-fold; beta-NAH, 37.5-fold; CD, 2.2-fold; alpha-1-EPI, 1.4-fold; p < 0.05). Surgical therapy resulted in a significant reduction of GCF markers compared with non-surgical treatment. However, the changes in clinical parameters were not different between AP and CP (P > 0.05). Analysis of the results suggests that the local inflammatory response in AP is characterized by increased release of inflammatory mediators of neutrophil origin into the GCF. Analysis of the data further suggests that surgical therapy is a more predictable method for removal of the pro-inflammatory etiology.

The role of bacterial and host proteinases in periodontal disease

It is abundantly obvious that the uncontrolled degradation and/or activation of host defense pathways is the major pathway by which the periodontal pathogen P. gingivalis promotes its growth and proliferation. By being able to shed host receptors, degrade cytokines, and activate coagulation, complement, and kallikrein/kinin pathways it is clear that this organism has found a mechanism(s) to evade host defense and at the same time develop a system for cannibalizing host proteins for its own nutritional usage (Fig 2). Thus, it seems only logical that the development of inhibitors against these bacterial proteinases would be a useful method for negating their activities and making such pathogens more susceptible to attack by host phagocyte cells. In this respect, the structure of the truncated form of RGP has just been elucidated. Thus, it should only be a question of time before inhibitors to this enzyme will be developed and, hopefully, be used to reduce the pathologies associated with the development of periodontitis and/or eliminate the disease altogether.

Activity and inhibition of elastase in GCF

The aim of this study was to investigate the presence of free elastase in GCF Samples were taken from inflamed sites in 12 subjects with gingivitis alone and from inflamed sites with and without tissue destruction in 19 patients having periodontitis. Elastase activity was measured with a low molecular weight substrate. To distinguish between free elastase and elastase bound to alpha-2-macroglobulin (A2MG), an excess of alpha-1-antitrypsin (A1AT) was added to the samples. The activity that could be inhibited by A1AT was considered as free elastase, and the uninhibited activity as derived from the elastase-A2MG complex. The elastase-A1AT complex was measured with an ELISA. Free elastase was found in almost all samples, but both the total amount and the proportion of free elastase were higher in samples from sites showing destruction. The elastase-A2MG complex was also increased in sites with tissue destruction, while there was no significant difference in the amount of A1AT complex between the 3 categories of sites. In conclusion, our study clearly reveals free elastase in GCF The elevated levels of free elastase in sites showing tissue destruction seem to be due to a combination of increased release of elastase and an inactivation of A1AT.