Baseline expression and effect of TGF-β1 on Type I and III collagen mRNA and protein synthesis in human odontoblasts and pulp cellsIn Vitro

Since growth factors have been suggested to regulate dentin collagen formation in response to external irritation, we investigated the effect of TGF-β1 on proα1(I) collagen mRNA expression in cultured mature human odontoblasts and pulpal fibroblasts, as well as cultured human pulp tissue, using quantitative PCR. Cultured gingival fibroblasts (GF) and osteoblasts (OB) served as controls. Also, type I collagen synthesis in cultured odontoblasts and pulp tissue, as well as type III collagen synthesis in odontoblasts, were studied by measuring respective procollagen (PINP and PIIINP) secretion into culture media with radioimmunoassay (RIA). Odontoblasts expressed significantly higher basic level of type I collagen mRNA than pulp tissue or pulp fibroblasts in culture, but markedly lower level than GF and OB cells. TGF-β1 (10 ng/ml) had negligible effects on type I collagen mRNA expression or PINP synthesis in cultured odontoblasts and pulp tissue, and PIIINP synthesis in the odontoblasts. In PF cells, the effect of TGF-β1 depended on culturing conditions; a 6-fold increase in mRNA expression was observed using serum-free medium but no effect was seen in the cells cultured with 10% FBS. In contrast, GF cells serving as controls were not markedly affected by the culture conditions, with 2-3-fold increase in mRNA expression by TGF-β1. These experiments demonstrate that mature human odontoblasts are capable of synthesizing type III collagen protein, and that TGF-β1 has negligible effect on mature human odontoblast and pulp tissue collagen expression.

Baseline expression and effect of TGF-beta 1 on type I and III collagen mRNA and protein synthesis in human odontoblasts and pulp cells in vitro

Since growth factors have been suggested to regulate dentin collagen formation in response to external irritation, we investigated the effect of TGF-beta 1 on pro alpha 1 (I) collagen mRNA expression in cultured mature human odontoblasts and pulpal fibroblasts, as well as cultured human pulp tissue, using quantitative PCR. Cultured gingival fibroblasts (GF) and osteoblasts (OB) served as controls. Also, type I collagen synthesis in cultured odontoblasts and pulp tissue, as well as type III collagen synthesis in odontoblasts, were studied by measuring respective procollagen (PINP and PIIINP) secretion into culture media with radio-immunoassay (RIA). Odontoblasts expressed significantly higher basic level of type I collagen mRNA than pulp tissue or pulp fibroblasts in culture, but markedly lower level than GF and OB cells. TGF-beta 1 (10 ng/ml) had negligible effects on type I collagen mRNA expression or PINP synthesis in cultured odontoblasts and pulp tissue, and PIIINP synthesis in the odontoblasts. In PF cells, the effect of TGF-beta 1 depended on culturing conditions; a 6-fold increase in mRNA expression was observed using serum-free medium but no effect was seen in the cells cultured with 10% FBS. In contrast, GF cells serving as controls were not markedly affected by the culture conditions, with 2-3-fold increase in mRNA expression by TGF-beta 1. These experiments demonstrate that mature human odontoblasts are capable of synthesizing type III collagen protein, and that TGF-beta 1 has negligible effect on mature human odontoblast and pulp tissue collagen expression.

Wound healing in ovariectomized rats: effects of chemically modified tetracycline (CMT-8) and estrogen on matrix metalloproteinases -8, -13 and type I collagen expression

Cutaneous wound healing is a complex process involving interactions of various cell types. Skin, in addition to certain other organs, is dependent on estrogen; and estrogen-deficiency is associated with impaired wound healing. Wound healing involves the action of collagenolytic matrix metalloproteinases (MMPs). We investigated the expression and localization of collagenolytic MMPs -8 and -13 by collagenase activity assay, Western immunoblot analysis, in situ hybridization and immunohistochemical staining as well as type I collagen by hydroxyproline content analysis and immunohistochemical staining in cutaneous wounds from aged Sham and ovarioectomized (OVX) rats. After wounding, OVX rats were treated with either placebo, chemically modified tetracycline-8 (CMT-8) or estrogen. We found that MMP-8 and MMP-13 mRNA were expressed in wound epithelium of all samples examined as evidenced by in situ hybridization. Type I collagen, which was abundant in all groups examined, was decreased in OVX rats, but was increased by both CMT-8 and estrogen treatments to the level of Sham group. Hydroxyproline analysis revealed similar results. Western blot data showed that all forms of MMP-8 and MMP-13 were clearly reduced in the CMT-8 treated group compared to OVX. Analysis of collagenolytic activity confirmed the decreased collagenolysis in skin wound extracts from CMT-treated rats when compared with skin wound extracts from OVX rats. Our results show for the first time that MMP-8 mRNA and protein are expressed in rat wound epithelium. We further show that CMT-8 and estrogen have a beneficial effect on skin wound healing in OVX rats by increasing the collagen content and reducing the MMP-mediated collagenolysis.

The in vivo expression of the collagenolytic matrix metalloproteinases (MMP-2, -8, -13, and -14) and matrilysin (MMP-7) in adult and localized juvenile periodontitis

Periodontal inflammation is characterized by irreversible degradation of periodontal ligament collagen fibers leading to loss of tooth attachment. Cultured gingival keratinocytes and fibroblasts express, in vitro, various matrix metalloproteinases (MMPs) which can degrade fibrillar collagens. We hypothesized that several MMPs are also synthesized in vivo by sulcular epithelium, and analyzed the collagenolytic MMPs (MMP-2, -8, -13, and -14) and matrilysin (MMP-7) in gingival tissue specimens and gingival crevicular fluid from adult and localized juvenile periodontitis patients by in situ hybridization, immunohistochemistry, and Western immunoblotting. MMP-2, -7, -8, and -13 were expressed in gingival sulcular epithelium. MMP-7 and -13 were also located in fibroblasts and macrophages, and MMP-8 in neutrophils. MMP-8- and -13-positive cells/mm2 were higher in periodontitis gingiva when compared with healthy control tissue (p < 0.01). In periodontal diseases, gingival sulcular epithelium expresses several, rather than a single, collagenolytic MMPs, and this proteolytic cascade is evidently responsible for the tissue destruction characteristic of adult and juvenile periodontitis.

Collagenases in different categories of peri-implant vertical bone loss

The loosening of dental implants is associated with peri-implant vertical bone loss. The mechanisms and mediators of this bone destruction are not known. To test the hypothesis that collagenase-2 and collagenase-3 might be markers or maybe even mediators in this process, we measured collagenase-2 (time-resolved immunofluorometric assay) and collagenase-3 (quantitative immunoblot) in peri-implant sulcus fluid in 49 implant sites in 13 patients. Vertical bone loss was graded as being < 1 mm, from 1 to 3 mm, or > 3 mm. The severity of inflammation, as rated according to Gingival Index, did not correlate with the category of bone loss (p > 0.05). Collagenase-2 and collagenase-3 were higher (p < 0.05) in the group which had lost > 3 mm of bone than in the two other groups. Gingival Index is not a clinically important marker for bone loss, but collagenase-2 and collagenase-3 in peri-implant sulcus fluid are. They might participate in peri-implant osteolysis.

Salivary matrix metalloproteinase (MMP-8) levels and gelatinase (MMP-9) activities in patients with type 2 diabetes mellitus

We studied the salivary levels and activities of the matrix metalloproteinases (MMP) -8 and -9 in 45 type 2 diabetic patients and 77 control subjects. The patients' mean glycosylated haemoglobin (HbA1c) was 8.7%, indicating an unsatisfactory metabolic control of the disease. The MMP levels were further related to the clinical and microbiological periodontal findings as well as to salivary flow rate and other factors. The salivary flow rate, albumin and amylase concentrations were similar in type 2 diabetic patients to those in the control group. The mean gingival and periodontal pocket indexes were higher in the diabetes group. The number of potential periodontopathogenic bacteria was lower, however, in the diabetic than in the control group. Zymography and immunoblotting revealed that the major MMPs in the type 2 diabetic patients' saliva were MMP-8 and MMP-9. Salivary MMP levels and activities in type 2 diabetic patients were in general similar to those in the control group. However, the correlation coefficients using multiple regression analysis revealed that gingival bleeding, pocket depths and HbA1c were associated with increased MMP-8 levels which, in turn, were negatively predicted by elevated plasma lipid peroxide levels in the diabetic group. Our data on salivary MMP-8 and -9 do not support the concept of generalized neutrophil dysfunction in unbalanced diabetes. Moreover, plasma lipid peroxidation levels reflecting the increased oxidative burden, which is generated mainly by triggered neutrophils, do not indicate neutrophil dysfunction due to diabetes, but may rather be related to the increased tissue damage in an uncontrolled disease. However. advanced periodontitis in type 2 diabetes seems to be related to elevated salivary MMP-8 levels which might be useful in monitoring periodontal disease in diabetes.

Prognostic factors in tongue cancer - relative importance of demographic, clinical and histopathological factors

The incidence of and mortality from squamous cell carcinoma (SCC) of the tongue have increased during the recent decades in the Western world. Much effort has been made to predict tumour behaviour, but we still lack specific prognostic indicators. The aim of our study was to evaluate the relative importance of the known demographic, clinical and histological factors in a homogeneous population-based group of patients with SCC of the mobile tongue. The demographic and clinical factors were reviewed retrospectively from primary and tertiary care patient files. Histological prognostic factors were determined from pre-treatment biopsies. The TNM stage was found to be the most important prognostic factor. In particular, local spread outside the tongue rather than spread to regional lymph nodes was related to poor prognosis. Several demographic and histopathological factors were closely related to TNM stage. When the cases were divided into stage I-II carcinomas and stage III-IV carcinomas, it appeared that the patient's older age (> 65 years), a high malignancy score and an absence of overexpressed p53 protein were associated with a poorer prognosis in stage I-II carcinomas. Such cases may require more aggressive treatment. Among patients with stage III-IV carcinomas, heavy use of alcohol was significantly associated with a poor disease-specific survival time.

Expression of estrogen receptor (ER) in oral mucosa and salivary glands

OBJECTIVES

To assess the expression of estrogen receptor (ER) in oral mucosa and salivary glands, buccal mucosal biopsies from ten postmenopausal women (taken before and during the hormone replacement therapy), as well as, single biopsies from 20 healthy 19-year-old women were analyzed for ER expression. Salivary gland biopsies were taken from the minor labial salivary glands (n=6), submandibular glands (n=5) and parotid gland (n=1) from women at different ages.

METHODS

total RNA extracted from the tissue samples was reverse-transcripted (RT) to single-stranded cDNA, and the RT-polymerase chain reaction (RT-PCR) product was subjected to nucleotide sequencing to confirm the match with ER cDNA. Immunohistochemistry (IHC) with a monoclonal ER antibody (ER-ICA, Abbott) and Western blot analysis with monoclonal antibody against ER-related antigen (ER-D5, Amersham) were performed on the biopsies taken from the postmenopausal women.

RESULTS

ER mRNA was expressed in 18/20 (90%) and 20/20 (100%) of the mucosal biopsies in the postmenopausal and 19-year-old women, respectively. The expression of mRNA was detected in all the submandibular gland samples, in the single parotid gland, as well as, in 4/6 (67%) of the labial glands. ER expression could not be detected by IHC, indicating either a very low level of expressed protein or difficulties in recognizing the epitopes by IHC. However, Western blot demonstrated 8/8 (100%) of the mucosal biopsies of postmenopausal women positive for ER-related antigen.

CONCLUSIONS

the presence of ER mRNA and immunoreactive ER protein suggests that estrogens have a biological role in oral mucosa and salivary glands.

Down-regulation of trypsinogen-2 expression by chemically modified tetracyclines: association with reduced cancer cell migration

Many types of human tumor express trypsinogen-2, which may be a significant factor in the activation of pro-MMPs and the invasiveness of tumors. Prevention of trypsinogen-2 expression in cancer cells might be of benefit in cancer therapy. We describe here chemicals capable of down-regulating the expression of trypsinogen-2. Doxycycline (DOXY) and chemically modified tetracyclines (CMTs), previously known as inhibitors of the matrix metalloproteinase (MMP)-dependent proteinase cascade, down-regulated the mRNA and protein expression of trypsinogen-2 by COLO-205 human colon adenocarcinoma cells at therapeutically attainable concentrations (0. 1 to 1.0 microM). DOXY specifically inhibited the activation of pro-MMP-9 and cell migration induced by enteropeptidase, a specific activator of trypsinogen. Pro-MMP-9 activation and cell migration were also inhibited by tumor-associated trypsin inhibitor (TATI), which is a highly specific inhibitor of trypsin. CMT-3 as well as CMT-5 also inhibited cell migration, but an effect on the enteropeptidase-enhanced activation of pro-MMP-9 was not observed. Our results indicate that CMTs, DOXY and TATI inhibit cancer cell migration by down-regulating trypsinogen-2 expression or activity. Inhibition of trypsinogen-2 expression may represent a mechanism contributing to the ability of CMTs to suppress the pericellular proteolytic activity of some tumors.

Expression of alpha(v)beta6 integrin in oral leukoplakia

The distribution of alpha(v)beta6 integrin was examined in oral leukoplakia, lichen planus and squamous cell carcinomas using immunohistochemistry. Controls included oral mucosal wounds, chronically inflamed and normal oral mucosa. Integrins beta1, beta3, beta4, beta5, fibronectin and tenascin were also studied. The integrin alpha(v)beta6 was highly expressed throughout the whole lesion of 90% of the squamous cell carcinomas but was not present in any of the normal specimens. alpha(v)beta6 integrin was also expressed in 41% of the leukoplakia specimens, and 85% of the lichen planus samples, but in none of the tissues with inflammatory hyperplasia or chronic inflammation. The expression of beta1 integrins was localized in the basal layer, and that of the beta4 at the cell surface facing the basement membrane of all specimens. The integrins beta3 and beta5 were absent from all normal and leukoplakia specimens. Fibronectin and tenascin were present in the connective tissue underneath the epithelium of all the sections, and their expression was similar in both alpha(v)beta6-positive and alpha(v)beta6-negative tissues. A group of 28 leukoplakia patients were followed 1-4 years after first diagnosis. In this group, initially alpha(v)beta6 integrin-positive leukoplakia specimens had high tendency for disease progression while alpha(v)beta6-negative specimens did not progress. These results suggest that the expression of alpha(v)beta6 integrin could be associated in the malignant transformation of oral leukoplakias.

Radiographic periodontal attachment loss as an indicator of death risk in the elderly

OBJECTIVES

Oral infections have been associated with serious systemic diseases and an increased risk of death. Our aims were to investigate whether radiographically-observed apical periodontitis lesions, carious teeth, periodontal attachment loss (horizontal bone loss, furcation lesions, number of teeth with infrabony periodontal pockets, the extent of infrabony periodontal pockets) and the sum of all these findings have any relationships with all-cause mortality within 4-year follow-up.

MATERIAL AND METHODS

292 community-dwelling elderly persons aged 76, 81 and 86 years. The number of deaths within 4 years was 54 (18.5%). In the dentate 169 subjects, of whom 32 (18.9%) deceased within 4 years, the mean number of teeth was 15.5 in men and 13.2 in women. The imaging method used was panoramic radiography supplemented by intraoral radiographs.

RESULTS

51% of the dentate subjects had infrabony pockets (mean 1.5, s.d. 2.2), and 40% had periapical periodontitis lesions (mean 1.0, s.d. 1.6). After controlling for age and gender, vertical bone loss judged as advanced infrabony pockets was associated with 4-year all-cause mortality (Odds ratio 2.2,1.0-4.7). Other associations were statistically insignificant.

CONCLUSION

Periodontal attachment loss may indicate an increased risk of death in the elderly.

The expression of MMP-8 in human odontoblasts and dental pulp cells is down-regulated by TGF-beta1

Recent findings show that matrix metalloproteinase-8 (MMP-8) is expressed, in addition to neutrophils, by human chondrocytes, cultured fibroblasts, and endothelial cells. We investigated the expression of MMP-8 in other human mesenchyme-derived cells, odontoblasts, and pulp tissue. Odontoblasts and pulp tissue were collected from extracted human teeth for MMP-8 mRNA analysis with reverse-transcription/polymerase chain-reaction (RT-PCR) and Southern blot. The expression, localization, and secretion of MMP-8 protein were studied with Western blot, immunohistochemistry, and immunofluorometric assay. The effect of TGF-beta1 (10 ng/mL) on the expression, secretion, and concentration of secreted MMP-8 was studied by odontoblast and pulp tissue culture methods (Tjäderhane et al., 1998a). RT-PCR demonstrated MMP-8 mRNA expression in native and cultured odontoblasts and pulp tissue and cultured pulp fibroblasts, with a 522-bp transcript comparable with that of bone marrow cells. The specificity of PCR was confirmed with Southern blot. Western blot with MMP-8-specific antibody detected 65- and 50-kDa proteins in native samples, representing latent and active forms of mesenchymal-type MMP-8, and in the conditioned odontoblast culture media, 50-kDa protein was observed. TGF-beta down-regulated the MMP-8 mRNA and concentration of secreted protein in both cultures. Immunohistochemical staining detected MMP-8 in odontoblasts. These findings indicate that mesenchyme-derived cells of the dentin-pulp complex express, synthesize, and activate MMP-8, which may, in concert with odontoblast-derived gelatinases, participate in organization of dentin organic matrix prior to mineralization.

Expression of laminin-5 in ameloblastomas and human fetal teeth

Extracellular matrix proteins have been shown to play important roles in the cell migration and differentiation in both normal and pathological conditions. In the present study, we used immunohistochemistry and in situ hybridization to determine the distribution of laminin-5 in ameloblastomas and developing human teeth. In ameloblastomas, the immunoreaction for the laminin-5 gamma2 chain was confined to the tumor cells of the peripheral area. The staining reaction was variable, being mostly weak and fragmented in the basement membrane structures surrounding the neoplastic islands. Some peripheral epithelial cells and some invading small ameloblastoma cell islands showed intense intracellular staining for the gamma2 chain. Tumor cells in the proliferating areas of ameloblastomas expressed gamma2 chain mRNA. The laminin-5 gamma2 chain was located beneath the dental lamina and in the outer, but not in the inner, enamel epithelium of the developing teeth. During the early hard tissue apposition stage, intense staining for the gamma2 chain was confined to ameloblasts, which also gave a strong signal for gamma2 chain mRNA. These results suggest that laminin-5 may contribute to the infiltrative and progressive growing potential of ameloblastomas. During human tooth development, however, laminin-5 may participate in the terminal differentiation of ameloblasts and in enamel matrix formation.

Matrix metalloproteinase 2 (gelatinase A) is related to migration of keratinocytes

The role of matrix metalloproteinases (MMPs) in cell migration was studied by measuring cell growth, migration, and production of MMP-2 and -9 in oral mucosal and skin keratinocytes cultured in the presence of synthetic MMP inhibitors. MMP-2 was the major gelatinolytic MMP produced by these cells while MMP-9 was produced at a low basal level. Inhibitor effects on MMP-9 production were therefore studied in keratinocytes stimulated by tumor necrosis factor alpha (TNFalpha). Tetracycline analogues at concentrations that inhibited the production of MMP-2 but not MMP-9 were able to drastically inhibit migration of both mucosal and skin keratinocytes. Tetracycline analogues also inhibited keratinocyte growth, an effect not found for the other inhibitors tested. Heterocyclic carbonate-derived compounds (LWs) that inhibited MMP-9 but not MMP-2 production had no effect on cell migration. Batimastat, a potent MMP inhibitor, did not have any effect on MMP production or cell growth but did inhibit keratinocyte migration. Tumor growth factor beta (TGFbeta) increased keratinocyte migration as well as both cell-associated and secreted MMP-2 production in wounded cell cultures. The secreted enzyme was partially converted into an active form. In this model batimastat totally blocked TGFbeta-promoted keratinocyte migration. Immunostaining of keratinocytes advancing into the wound revealed that MMP-2 was localized in extracellular matrix contactlike structures against the endogenously produced laminin-5-rich matrix. MMP-9 was localized diffusely along the cell membranes. Using in situ hybridization we observed that in chronically inflamed human gingiva MMP-2 is expressed in epithelium extending into subepithelial connective tissue. These results suggest that MMP-2 plays a specific role in epithelial migration, possibly by detaching the advancing cells from the pericellular matrix or by activating other MMPs.

Collagenase-3 (MMP-13) and its activators in rheumatoid arthritis: localization in the pannus-hard tissue junction and inhibition by alendronate

The hypothesis of the present work was that the pannus tissue overlying the articular hard tissues has an aggressive phenotype and contains the newly discovered collagenase-3 and its endogenous inducers and activators. We therefore analyzed the eventual presence of collagenase-3 and its regulation at the pannus-cartilage junction. Collagenase-3 mRNA (in situ hybridization) and enzyme protein (ABC and immunofluorescence staining) were found in the pannocytes in the pannus-hard tissue junction. Inflammatory round cells associated with the critical interface contained TNF-alpha and IL-1beta. These cytokines induced collagenase-3 secretion in cultured rheumatoid synovial fibroblasts. Procollagenase-3 activators, stromelysin-1, 72 kDa type IV collagenase/gelatinase and membrane-type 1-MMP, were also found in the pannus-hard tissue junction. Active collagenase-3 was inhibited with alendronate (IC50 = 500-750 microM). Collagenase-3, due to its substrate profile and local synthesis in a milieu favoring its activation, might play a major role in the degradation of cartilage type II and bone type I collagens. Alendronate, at concentrations attainable in vivo, is able to inhibit collagenase-3. This might offer an option to control collagenase-3-mediated tissue destruction in rheumatoid arthritis.

Tumor targeting with a selective gelatinase inhibitor

Several lines of evidence suggest that tumor growth, angiogenesis, and metastasis are dependent on matrix metalloproteinase (MMP) activity. However, the lack of inhibitors specific for the type IV collagenase/gelatinase family of MMPs has thus far prevented the selective targeting of MMP-2 (gelatinase A) and MMP-9 (gelatinase B) for therapeutic intervention in cancer. Here, we describe the isolation of specific gelatinase inhibitors from phage display peptide libraries. We show that cyclic peptides containing the sequence HWGF are potent and selective inhibitors of MMP-2 and MMP-9 but not of several other MMP family members. Our prototype synthetic peptide, CTTHWGFTLC, inhibits the migration of human endothelial cells and tumor cells. Moreover, it prevents tumor growth and invasion in animal models and improves survival of mice bearing human tumors. Finally, we show that CTTHWGFTLC-displaying phage specifically target angiogenic blood vessels in vivo. Selective gelatinase inhibitors may prove useful in tumor targeting and anticancer therapies.

Expression of integrin alpha9 subunit and tenascin in oral leukoplakia, lichen planus, and squamous cell carcinoma

OBJECTIVES

Integrin alpha9 subunit is a member of beta1 integrin family and binds tenascin (TN). It is expressed by stratified squamous epithelium and may be associated with cell differentiation and growth. We studied if the expression of alpha9 integrin and TN is altered in leukoplakia, lichen planus, and squamous cell carcinoma (SCC).

METHODS

Frozen sections of tissue samples obtained from normal human keratinized (16 subjects) and non-keratinized (three subjects) oral mucosa, oral leukopakias with dysplasia (19 subjects), reticular type lichen planus (nine subjects), or oral mucosal SCC (23 subjects) were stained immunohistochemically with antibodies against alpha9 integrin and TN.

RESULTS

In contrast to its most prominent localization at the cell membranes of the basal epithelial cells in the normal mucosa, alpha9 integrin was localized in a more diffuse pattern with focal loss of expression at the epithelial cell membranes in leukoplakic dysplasia, lichen planus, and SCC. In some areas of SCC, alpha9 integrin localized throughout all cell layers of the tumor epithelium. In most areas, alpha9 integrin colocalized with TN but in heavily inflamed areas there was focal loss of TN and alpha9 integrin at the basement membrane zone.

CONCLUSIONS

The findings show that alpha9 integrin expression is altered in leukoplakic dysplasia, lichen planus, and SCC.

Scientific basis of a matrix metalloproteinase-8 specific chair-side test for monitoring periodontal and peri-implant health and disease

Matrix metalloproteinases (MMPs), especially collagenase-2 (MMP-8), are key mediators of irreversible tissue destruction associated with periodontitis and peri-implantitis. MMP-8 is known to exist in elevated amounts and in active form in the gingival crevicular fluid (GCF) and peri-implant sulcular fluid (PISF) from progressing periodontitis and peri-implantitis lesions and sites, respectively. (Sorsa et al. Ann. N.Y. Acad. Sci. 737: 112-131 [1994]; Teronen et al. J. Dent. Res. 76: 1529-1537 [1997]). We have developed monoclonal antibodies to MMP-8 (Hanemaaijer et al. J. Biol. Chem. 272: 31504-31509 [1997]) that can be used in a chair-side dipstick test to monitor the course and treatment of periodontitis and peri-implantitis. Monoclonal and polyclonal antibody tests for MMP-8 coincided with the classical functional collagenase activity test from GCF and PISF (Sorsa et al. J. Periodont. Res. 22: 386-393 [1988]) in periodontal and peri-implant health and disease. In future a chair-side functional and/or immunological MMP-test can be useful to diagnose and monitor periodontal and peri-implant disease and health.

MMP inhibition and downregulation by bisphosphonates

Bisphosphonates are a group of drugs capable of inhibiting bone resorption, and are thus used for the treatment of bone diseases, such as Paget's disease, osteoporosis, and for bone metastases of malignant tumors. Their primary cellular target is considered to be the osteoclast. The molecular mechanisms responsible for the downregulation of bone resorption by bisphosphonates have remain unclear. We have discovered that various matrix metalloproteinases (MMPs) are inhibited in vitro by several bisphosphonates. This novel finding may, in part, explain the efficacy of bisphosphonates in their current indications in humans. In enzyme activity tests using purified and recombinant enzymes, we have observed the inhibition of MMP-1, -2, -3, -7, -8, -9, -12, -13, and -14 by clondronate, alendronate, pamidronate, zolendronate, nedrinate, and clodrinate. The IC50s range from 50 to 150 microM. We have also shown that clodronate can downregulate the expression of MT1-MMP protein and mRNA in several cell lines. Additionally, several bisphosphonates decrease the degree of invasion of malignant melanoma (C8161) and fibrosarcoma (HT1080) cells through artificial basement membrane (Matrigel) in cell cultures at IC50s of 50-150 microM and below. Having low toxicity and proven to be well tolerated after several years in human use, bisphosphonates have the potential to become one of the main MMP-inhibitors for MMP-related human soft and hard tissue-destructive diseases in the near future.

T(H)1 cytokines are produced in labial salivary glands in Sjögren's syndrome, but also in healthy individuals

The aim of the present study was to assess the T cell cytokines IFN-gamma, IL-2, IL-4 and IL-5 in labial salivary glands (LSG) in Sjögren's syndrome (SS) and healthy controls using RT-PCR and immunohistochemistry. IFN-gamma is always or almost always produced in SS and in healthy controls. IL-2 was also found in some samples, but IL-4 and IL-5 were not. Less than 2% of all inflammatory mononuclear cells contained immuoreactive IFN-gamma or IL-2. Cytokine mRNA profile in LSGs in SS is skewed towards a T(H)1 pattern. The classical T(H)1 cytokines are also produced in normal glands, even in the absence of foci. T(H)1 type response may play an active role as part of the mucosal associated lymphoid tissue/responses, perhaps in prevention of reactivation of latent viruses. This may also make the exocrine glands a locus minoris resistentiae when the self tolerance is broken.