Secretion of gelatinases and activation of gelatinase A (MMP-2) by human rheumatoid synovial fibroblasts.

In monolayer cultures human rheumatoid synovial fibroblasts (HRSF) secrete gelatinase A (MMP-2) and, unlike other human fibroblasts, to a minor extent also gelatinase B (MMP-9) as inactive proenzymes. In this regard HRSF resemble the fibrosarcoma cell line HT-1080. Unlike HT-1080, however, HRSF do not increase the secretion of MMP-9 in response to phorbol-12-myristate-13-acetate. This indicates that in HRSF the protein kinase C pathway for an enhanced MMP-9 secretion is inactive. None of the substances used in our study increased MMP-9 secretion, but some of them inhibited MMP-9 secretion. The secretion of MMP-2 could not be enhanced either, not even by dbcAMP, which has been reported to be effective in Sertoli and peritubular cells. Activation of MMP-2 in HRSF could be induced by treatment with concanavalin A (ConA) or cytochalasin D, as was shown for other cell types. This activation was not accompanied by a significant change in the amount of secreted TIMP-1 and TIMP-2. In contrast to reports on human skin fibroblasts, however, the activation of MMP-2 could not be induced in HRSF by treatment of the cells with monensin or sodium orthovanadate. Moreover, monensin was shown to act as an inhibitor of ConA- or cytochalasin D-mediated activation. Additionally, and in contrast to a report on a rat fibroblast cell line, MMP-2 activation is not mediated via the MAP kinase pathway in HRSF: PD 98059, a specific inhibitor of MAP kinase kinase, did not inhibit the activation of MMP-2. Similarly ineffective were PD 169316, an inhibitor for p38 MAP kinase, other inhibitors for protein kinases as lavendustin A, Gö 6983, wortmannin, rapamycin, as well as the protein tyrosine kinase inhibitors herbimycin A and genistein. Only staurosporin, a broad spectrum inhibitor of protein kinases, and the ionophores monensin and A 23187 effectively inhibited MMP-2 activation in HRSF. Our results demonstrate that MMP-2 can be activated by quite different pathways, and that different cells, even when belonging to the fibroblast family, do not necessarily use the same activating pathways.

Nitric oxide synthesis is decreased in periodontitis.

OBJECTIVES: In order to study the possible role of nitric oxide (NO) in the development of periodontitis, we measured the concentration of its stable metabolite nitrite (NO2-) in the saliva of patients with periodontitis and healthy subjects. MATERIALS AND METHODS: We have analysed salivary NO2- concentrations in 25 subjects with rapidly progressive periodontitis (RPP), 25 with adult periodontitis (AP) and in 25 periodontally-healthy persons. The concentrations of NO2- were determined by the Griess reaction in microtitration plates. Periodontal tissue destruction was determined by measuring the attachment level loss using standard methods. RESULTS: Subjects with periodontitis had significantly less NO2- in saliva than healthy subjects. Subjects with RPP had lower NO2- concentrations than those with AP Parotid gland saliva contained less NO2- than sublingual gland or total saliva. CONCLUSIONS: Local NO production is decreased in patients with periodontitis. This effect is more pronounced in those with severe types of disease.

Aspartat aminotransferase--a marker of periodontal disease activity.

Active and inactive periodontal pockets exist in periodontal disease and the progression of periodontitis is episodic and cyclical. Current diagnostic tests do not distinguish between active and inactive lesions. Objective assessment of disease activity could significantly affect periodontal therapy. Aspartat aminotransferase (AST) activity in gingival crevicular fluid is a potential quantitative marker of periodontal disease activity. Thirty-six patients with periodontitis, twenty with adult periodontitis and sixteen with rapidly progressive periodontitis were evaluated clinically prior to treatment and AST activity in periodontal pockets was determined prior to and after initial therapy. Clinical measures included plaque index, gingival inflammation degree and attachment loss. The results show that AST levels do not correlate with clinical indices and that they decrease after treatment. AST is a possible novel biochemical marker of periodontal disease activity independent of commonly used clinical measures. It could also be useful for early monitoring of treatment success.

Inflammatory mediators in saliva of patients with rapidly progressive periodontitis during war stress induced incidence increase.

Rapidly progressive periodontitis (RPP) results from the interaction between the periodontal microflora and the host. Stress is believed to play an important role in determining host responses, and it has been proposed that hyperactivity of host defense mechanisms significantly increases tissue destruction typical for this disease. During a period of four months we have diagnosed 20 patients with acute RPP, all of them active participants in battles of the Croatian liberation war with posttraumatic stress disorder (PTSD) related symptoms. In these patients we analyzed biochemical parameters in unstimulated saliva and performed microbiological analyses of periodontal pockets. These findings were compared with those of patients with adult periodontitis (AP), edentulous and healthy persons, none of whom participated in the war. Persons with AP had reduced concentrations of host humoral defense factors in saliva (C-reactive protein, C3 component of complement, and aplha alpha 2-macroglobulin), while patients with RPP had increased concentration of interleukin-6 (IL-6). IL-6 is released by host inflammatory cells and is a mediator of bone resorption. Actinobacillus actinomycetemcommitans and Peptostreptococcus were more frequently isolated from patients with RPP. We interpret these results as indicators of the importance of stress in the causation of RPP, with host inflammatory hyperactivity playing an important role in tissue destruction, specially alveolar bone resorption possibly caused by increased local levels of IL-6.