Examination on Candida spp. in refractory periapical granulomas

AIM

To examine the occurrence of Candida spp. in refractory periapical granulomas.

METHODOLOGY

One hundred and three surgically removed periapical granulomas were subjected to molecular analysis for the occurrence of Candida albicans. DNA was extracted from the samples using a modified phenol/chloroform/isoamyl alcohol method and was subjected to polymerase chain reaction (PCR) with OPA-03 and repetitive sequence (GACA)4 primers. The PCR products were separated in agarose gel electrophoresis, stained with ethidium bromide, visualized using UV light and the sequences were analysed. Samples indicating possible occurrence of Candida were further investigated by histological and immunohistological methods. Periodic acid-Shiff staining (PAS) was used to detect yeast cells and hyphae, and specific monoclonal antibodies to recognize high molecular mass mannoproteins present in the C. albicans cell wall. DNA extraction was controlled by running PCR using beta-actin primers (a housekeeping gene). C. albicans CCUG19915, C. tropicalis ATCC750, C. krusei ATCC6258, C. guilliermondii ATCC6260 and C. glabrata CCUG32725 served as positive controls in PCR. A tissue preparation of chronic atrophic candidosis in oral buccal mucosa served as a positive control for histological and immunohistological examinations.

RESULTS

Polymerase chain reaction with beta-actin primers indicated successful DNA extraction in 68 out of 103 samples. The majority of the samples (50) were negative whereas 18 of the samples showed PCR products indicating possible occurrence of Candida spp. PAS-staining and immunohistological examination of these samples were, however, negative. Further analysis of the PCR products revealed sequences not typical for Candida spp.

CONCLUSIONS

Candida spp. do not seem to occur in periapical granuloma.

Modulation of collagen synthesis and mRNA by continuous and intermittent use of topical hydrocortisone in human skin

BACKGROUND

Glucocorticoids have been shown to downregulate collagen synthesis in human skin in vivo, thereby contributing to skin atrophy.

OBJECTIVES

To compare the effects of continuous and intermittent use of topical hydrocortisone on skin collagen synthesis and, furthermore, to elucidate the mechanism of collagen synthesis reduction induced by hydrocortisone.

METHODS

Collagen propeptides reflecting the synthesis rate of type I and III collagens were studied from suction blister fluids in nine healthy subjects after 3 weeks of continuous (twice daily) or intermittent (on three consecutive days weekly) topical hydrocortisone treatment and 2 weeks after the termination of treatment. Type I collagen mRNA was studied in the same subjects from skin biopsies by using in situ hybridization (ISH) after 3 weeks of treatment.

RESULTS

Three weeks of continuous treatment decreased the types I and III collagen propeptides in suction blister fluid by 89% and 82%, respectively, while intermittent treatment resulted in a corresponding decrease of 53% and 50%. ISH studies from skin biopsies showed type I collagen mRNA to be markedly reduced in fibroblasts after continuous and intermittent steroid treatment. After a 2-week drug-free interval, the synthesis rate was completely restored in both areas, and some subjects even showed upregulation of synthesis in previously steroid-treated skin.

CONCLUSIONS

Continuous hydrocortisone for 3 weeks markedly decreases collagen propeptides and corresponding mRNA in human skin. Intermittent hydrocortisone has a less marked effect on the collagen synthesis rate.

MMP-9 activation by tumor trypsin-2 enhances in vivo invasion of human tongue carcinoma cells

Various human cancer cells express tumor-associated trypsinogen-2 (TAT-2), which can efficiently activate matrix metalloproteinases (MMPs) in vitro. MMP-2 and MMP-9 are particularly associated with the invasive malignant potential of several tumors. To investigate the role of TAT-2 in tumor invasion, we overexpressed TAT-2 in two malignant human squamous cell carcinoma cell lines of tongue and in non-malignant human papilloma virus transformed gingival keratinocytes. The TAT-2 overexpression significantly increased the levels of active MMP-9 in the most malignant cell line. TAT-2-transfected cells intravasated (invaded blood vessels) up to 60% more efficiently than did the control cells in an in vivo chick embryo chorioallantoic membrane invasion model. This increased intravasation was almost completely abolished by a specific tumor-associated trypsin inhibitor (TATI). These results indicate that TAT-2 has a role in the invasive growth of tumors, either alone or in cascade with gelatinases, especially by generating active MMP-9.

Matrix metalloproteinase-8 (MMP-8) in pulpal and periapical inflammation and periapical root-canal exudates

AIM

To study the presence, levels and molecular forms of matrix metalloproteinase (MMP) -8 (collage-nase-2) in pulpal and periapical inflammation, and the changes in MMP-8 levels in root-canal exudates during root-canal treatment.

METHODOLOGY

Periapical exudate samples were collected from 11 necrotic teeth with radiographically verified periapical periodontitis during three root-canal treatment visits with interappointment calcium hydroxide (Ca(OH)2) medication. MMP-8 levels and molecular forms were analyzed with immunofluorescent assay (IFMA) and Western immunoblot. Inflamed pulp tissue and periapical granuloma tissue (n = 10 for both) were obtained from other patients and used for MMP-8 immunohistochemical (IHC) staining.

RESULTS

The periapical exudate samples demonstrated marked differences in MMP-8 levels between the teeth in the first visit and significant decrease in MMP-8 levels during the root-canal treatment (P = 0.0107). One specimen failed to show a decrease in MMP-8 below 1000 ng mL(-1) a vertical root fracture was later diagnosed and the tooth extracted. IHC staining showed that in addition to PMN-leucocytes, macrophages and plasma cells produced MMP-8 in pulp and periapical granulomas.

CONCLUSIONS

The findings demonstrate the presence of MMP-8 in the inflamed pulp and periapical tissue, indicating that MMP-8 has a role in pulpal and periapical inflammation, most likely participating in tissue extracellular matrix degradation. They further indicate that MMP analysis from periapical exudate could be used to indicate and monitor inflammatory activity and the success of treatment in teeth with periapical lesions.

The localization of matrix metalloproteinase-20 (MMP-20, enamelysin) in mature human teeth

MMP-20 (enamelysin), the matrix metalloproteinase family member discovered in the enamel organ, has also been detected in odontoblasts during dentin formation. We studied the presence and localization of MMP-20 in mature human teeth in health and disease. In immunohistochemistry, MMP-20-positive staining was observed most intensively in the radicular odontoblastic layer and also in dilated dentinal tubuli of caries lesions. By Western blotting, MMP-20 was detected in odontoblasts and pulp tissue of both sound and carious teeth, in dentinal fluid and dentin of sound teeth, but not in soft carious dentin. We conclude that MMP-20 produced during primary dentinogenesis is incorporated into dentin and may be released during caries progression. The main cellular source of MMP-20 in the dentin-pulp complex is the odontoblasts, which secrete MMP-20 into the dentinal fluid.

The relationship between MMPs and pH in whole saliva of radiated head and neck cancer patients

BACKGROUND

Radiation therapy for head and neck tumour patients may lead to decreased salivary flow, oral mucosal lesions and increased caries experience. Salivary matrix metalloproteinases (MMPs) may participate in the pathogenesis of mucosal lesions and dentinal caries. The aims of this study were: (i) to assay the presence, molecular forms and proteolytic activity of MMP-8 (collagenase-2) and MMP-9 (gelatinase B) in the whole saliva of head and neck cancer patients having radiation therapy; (ii) to see whether salivary pH affects the activity of MMP-8 and MMP-9; and (iii) to find out the possible connection between MMP-8 and MMP-9 with the eruption of oral mucosal lesions during radiation therapy.

METHODS

The whole saliva samples of 39 head and neck cancer patients having radiation therapy were collected before, during and after radiation therapy, and saliva flow rate, pH, buffer capacity, Streptococcus mutans, Lactobacillus and Candida albicans were measured. Any oral mucosal lesions were examined during each visit. The levels of MMP-8 were measured by immunofluorometric assay (IFMA) and the presence of different MMP-8 forms was analysed using Western immunoblotting. The presence and molecular forms of MMP-9 were analyzed by gelatin zymography. MMP-9 capture activity assay was used to determine the APMA-activated MMP-9 activity (total) and the endogenously active MMP-9 (free activity).

RESULTS

Salivary flow rate, buffer capacity and pH decreased, and the levels of Lactobacilli increased significantly, during the first half of the radiation therapy. The endogenously activated salivary MMP-9 correlated with low salivary pH (P = 0.013). No connection was found between the oral mucosal lesions and salivary MMP-8 or MMP-9.

CONCLUSIONS

In this study, salivary MMP-8 or MMP-9 did not correlate with the presence of radiation induced oral mucosal lesions, but the activation of MMP-9 may be dependent on pH.

Regulation and interactions of MT1-MMP and MMP-20 in human odontoblasts and pulp tissue in vitro

MT1-MMP is a cell-membrane-bound metalloenzyme that activates other proMMPs such as proMMP-2 and -13. We studied MT1-MMP expression in mature human odontoblasts and pulp tissue, the regulation of MT1-MMP expression by growth factors TGF-beta1 and BMP-2, and the activation of odontoblast-derived MMP-20 by MT1-MMP. MT1-MMP mRNA is expressed by native and cultured mature human odontoblasts and pulp tissue. Western blot analysis of human odontoblasts and pulp tissue detects 65- and 51-kDa pro- and active forms of MT1-MMP, and smaller truncated MT1-MMP forms. BMP-2 down-regulates MT1-MMP expression in odontoblasts and pulp tissue, while TGF-beta1, alone or with BMP-2, decreases MT1-MMP mRNA levels only slightly. We also demonstrate that MT1-MMP is capable of converting proMMP-20 into a form corresponding to the active MMP-20. In conclusion, this study demonstrates the expression and differential regulation of MT1-MMP in human dentin-pulp complex cells, and the activation of MMP-20 by MT1-MMP.

Expression and regulation of collagenase-2 (MMP-8) in head and neck squamous cell carcinomas

MMP-8 (collagenase-2) is the most effective collagenase to initiate type I collagen degradation. Since initiation of lysis of the surrounding collagen matrix is an essential prerequisite for carcinoma cells to spread, this study investigated the expression of MMP-8 in squamous cell carcinoma (SCC) of the head and neck in vivo and in vitro. Most of the recently established head and neck carcinoma cell lines (22/25), corresponding tumour (5/7) and dermal (2/2) fibroblasts, commercial tongue carcinoma (HSC-3 and SCC-25), and transformed keratinocyte cell lines of the tongue (IHGK) and skin (HaCaT) expressed MMP-8 mRNA analysed by the PCR method. Western blotting revealed a latent 50 kD band in concentrated culture media of carcinoma cells and corresponding tumour and dermal fibroblasts. The expression of immunoreactive MMP-8 protein was reduced 30% by transforming growth factor beta-1 (TGF-beta1) at 1 ng/ml concentration and 60% at 10 ng/ml concentration, but up-regulated 2- and 2.5-fold after 10 nM and 100 nM phorbol 12-myristate 13 acetate (PMA), respectively. Immunohistological staining localized MMP-8 protein in a few malignant invading tumour cell islands, certain fibroblasts, polymorphonuclear neutrophils (PMNs), and plasma cells. In situ hybridization revealed a faint sporadic signal in carcinoma cells of all eight tissue sections analysed. It is concluded that tissue from head and neck carcinomas can express MMP-8 both in vivo and in vitro. Since the amount of MMP-8 in carcinoma and stromal cells is rather low, MMP-8 may have a potential role, with other collagenases, in the proteolysis of connective tissue associated with the spreading of invasive carcinoma.

Smoking affects collagen synthesis and extracellular matrix turnover in human skin

BACKGROUND

Smoking is associated with premature facial wrinkling and aberrant wound healing, but the underlying mechanisms of skin injury are poorly understood.

OBJECTIVES

To compare the in vivo collagen synthesis and degradation in the skin of smokers and non-smokers.

METHODS

The study population consisted of 47 current smokers and 51 individuals who had never smoked from northern Finland. Suction blisters were induced in the sun-protected upper inner arm of the study subjects, after which suction blister fluid (SBF) was collected for analyses of the levels of aminoterminal procollagen propeptides of type I and III collagens (PINP and PIIINP, respectively), matrix metalloproteinase (MMP)-8 and tissue inhibitor of MMP (TIMP)-1. PINP, PIIINP and TIMP-1 were also determined from serum samples. The levels of active and pro MMP-1 were assessed from deep-frozen skin biopsies by Western blotting.

RESULTS

The synthesis rates of type I and III collagens were lower by 18% and 22%, respectively, in the SBF of the smokers compared with the non-smokers. The levels of MMP-8 were higher by 100% in the SBF of the smokers. The levels of MMP-1 in the skin biopsies did not differ significantly between the groups. The levels of TIMP-1 in SBF were 14% lower in the smokers than in the non-smokers, whereas the serum concentrations of TIMP-1 did not differ between the groups.

CONCLUSIONS

Smoking decreases the synthesis rates of type I and III collagens in skin in vivo and alters the balance of extracellular matrix turnover in skin.

Collagenase-2 (MMP-8) and collagenase-3 (MMP-13) in adult periodontitis: molecular forms and levels in gingival crevicular fluid and immunolocalisation in gingival tissue

AIM

To determine the cellular and molecular forms of MMP-8 (collagenase-2) and MMP-13 (collagenase-3) associated with chronic adult periodontitis by examining the species present in gingival crevicular fluid (GCF) and enzyme distribution in gingival tissue.

METHODS

30-s GCF samples were collected directly from the periodontal pockets of 12 untreated patients using filter paper strips. After elution into buffer, the samples were examined by Western immunoblotting with polyclonal antibodies for MMP-8 and MMP-13 and quantification by scanning image analysis. Individual band intensities were expressed as a percentage of total sample absorbance and mean patient values were calculated. Gingival tissue from 6 patients was fixed in formalin and embedded in paraffin wax. MMP-8 and MMP-13 were localised using the same antibodies and an avidin-biotin-peroxidase detecting system. Double staining was performed with a contrasting substrate reaction.

RESULTS

The majority of MMP-8 staining in pre-treatment GCF was present in 80, 75 and 60 kD bands corresponding to prepro-, pro- and active forms of PMN-type enzyme. 43 and 38 kD bands evidently represented active, fibroblast-type MMP-8. Immunoreactivities at >100 kD and < or =30 kD were probably enzyme-inhibitor complex and degraded fragments, respectively. MMP-13 was seen mainly as 60 kD proenzyme with some 40 kD active enzyme and a small proportion of >100 kD complex. The percentages of MMP-8 PMN-type enzyme and MMP-13 proenzyme bands correlated significantly with gingival and bleeding indices (p<0.05). Immunohistochemistry demonstrated MMP-8 in PMNs, sulcular epithelial and also plasma cells in inflamed gingival connective tissue. MMP-13 immunoreactivity was detected in the sulcular epithelium and in macrophage-like cells.

CONCLUSION

Multiple species and elevated levels of both MMP-8 and MMP-13 from many rather than single cellular sources in the diseased periodontium are identified in untreated periodontitis GCF and active forms contribute to GCF collagenase activity.

Altered expression of collagen XVII in ameloblastomas and basal cell carcinomas

BACKGROUND

Collagen XVII (BP180) is an epithelial transmembrane protein, which presumably plays a role in cell migration and differentiation under both physiological and pathological conditions. Ameloblastoma, the most common odontogenic neoplasm, and basal cell carcinoma (BCC) of the skin exhibit similar growth patterns and share histological features.

METHODS

Here, we examined the distribution and expression of collagen XVII in ameloblastomas and BCCs using immunohistochemistry and non-radioactive in situ hybridization. In both tumors, the distribution of collagen XVII varied in different parts of the lesions.

RESULTS

In ameloblastomas, immunostaining for collagen XVII was usually localized in the basal and suprabasal cells of the tumor nests, although in some tumors, a diffuse intracellular staining was detected in the central cells of the neoplastic islands. In BCCs, collagen XVII was mostly seen as diffuse cytoplasmic staining in some central and peripheral cells of the tumor islands and also at the cell membranes in the basal keratinocytes of the epidermis overlying the tumor nests. Double immunostaining with antibody against gamma2 chain of laminin-5 showed that these two components of the keratinocyte adhesion complex are usually co-localized in ameloblastomas and BCCs. In both tumors, collagen XVII mRNA was found in the basal epithelial cells and in some central and peripheral cells of the tumor islands, while the stromal cells were negative.

CONCLUSIONS

These findings indicate that the expression of collagen XVII may be differentially regulated in various parts of the tumor. Diffuse intracellular distribution of collagen XVII and a consequent loss of critical cellular attachments may contribute to the infiltrative and progressive growing potential of tumors.

Expression and regulation of MMP-20 in human tongue carcinoma cells

Human matrix metalloproteinase-20 (MMP-20, enamelysin) fragments the enamel-specific protein amelogenin and has been shown to be synthesized exclusively by odontoblasts and ameloblasts and in certain odontogenic tumors. Here we demonstrate, for the first time, the expression of MMP-20 mRNA and protein in two carcinoma cell lines originating from the tongue. Treatment of the SCC-25 and HSC-3 cells with phorbol 12-myristate 13-acetate (10 nmol/L) up-regulated MMP-20 mRNA and protein expression by up to 1.6-fold, but transforming growth factor beta (10 ng/mL) had no effect. The latent proform of recombinant (r) human MMP-20 was converted by tumor-related trypsin-2. Activated rMMP-20 did not degrade type I or type II collagen, but efficiently hydrolyzed fibronectin, type IV collagen, laminin-1 and -5, tenascin-C, and beta-casein. This implies that MMP-20 not only participates in dental matrix remodeling but is also present in tongue carcinoma cells.

In vivo localization of gelatinases (MMP-2 and -9) by in situ zymography with a selective gelatinase inhibitor

In situ zymography provides a tool to localize proteolytic activity in tissues in vivo. However, it has been difficult to discriminate between the proteases responsible for the detected activity. We used a selective tissue-permeable gelatinase inhibitor, the CTTHWGFTLC-peptide (CTT) in inflamed human gingiva. The CTT-peptide was evidenced to home, target to, and selectively inhibit the areas of gelatinolytic activity in inflamed human gingiva expressing MMP-2 and -9. Gelatinolytic activity, MMP-9 immunoreactivity, and mRNA expression as well as CD-45-positive inflammatory cells colocalized well in the inflamed human gingival connective tissue. Gelatinolytic activity corresponding to MMP-2 colocalized with laminin-5 gamma2-chain immunoreactivity and was detected in the close vicinity of the sulcular basement membrane region. Furthermore, the CTT-peptide inhibited beta-caseinolysis by human MMP-2 and MMP-9 as well as laminin-5 gamma2-chain degradation by MMP-2 in vitro. Thus, the CTT-peptide may prove to be a useful tool (i) to discriminate between gelatinolytic proteases detected by in situ zymography and (ii) to preventMMP-2-dependent induction of epithelial cell migration and gelatinase-dependent tissue destruction in inflammatory and malignant diseases.

Association of trypsin-2 with activation of gelatinase B and collagenase-2 in human bronchoalveolar lavage fluid in vivo

BACKGROUND

Tissue injury mediated by matrix metalloproteinases (MMPs) is a hallmark of inflammatory lung diseases. Latent secreted proMMPs must be activated to be catalytically competent.

AIM

Our aim was to analyse an involvement of the trypsin-2, trypsin-2-alpha1-proteinase inhibitor (PI) complex and tumour-associated trypsin inhibitor (TATI) in the in vivo activation of proMMP-8, -9 and -2.

METHODS

Concentrations of trypsin-2, trypsin-2-alpha1-PI complex and TATI in bronchoalveolar lavage fluid (BALF) were analysed by immunofluorometry. Molecular forms and expression of trypsin-2 and trypsin-2-alpha1-PI complex were identified by Western immunoblot and immunocytochemistry. Gelatinolytic and collagenolytic activities were measured by substrate-based activity assays.

RESULTS

BALFs from 16 of 43 patients and BALFs from five of 15 healthy controls contained trypsin-2-alpha1-PI complex. TATI was found in all healthy control BALFs (median 0.12 microg/L, range 0.02-0.66 microg/L) whereas 8 of 43 BALFs from patients (median 0, range 0-0.64 microg/L, P = 0.0001) contained TATI. Patient BALFs showed significantly increased activation of MMP-9 and MMP-8 compared with healthy controls. The concentrations of trypsin-2-alpha1-PI complex correlated with the in vivo activation of MMP-9 and -8 (r = 0.68, P = 0.002 and r = 0.61, P = 0.008) but not with the activation of MMP-2 in BALFs.

CONCLUSION

Results show a key role of trypsin-2 in the in vivo activation of proMMP-8 and -9 in inflammatory lung diseases.

The effects of high levels of glucose and insulin on type I collagen synthesis in mature human odontoblasts and pulp tissue in vitro

High levels of dietary sucrose affect the metabolism of the pulp-dentin complex and enhance the caries process in dentin. The high-sucrose diet reduces dentin formation in young rats (Tjäderhane et al., 1994; Hietala and Larmas, 1995; Tjäderhane, 1996) and in pups of rat dams fed high-sucrose diet during lactation (Pekkala et al., 2000a). However, the mechanisms behind the effects are unknown. A direct effect of elevated blood glucose or an indirect effect via insulin has been suggested. We investigated the effects of high glucose and insulin on type I collagen synthesis in human odontoblasts and pulp tissue in vitro, using an organ culture method for functional post-mitotic odontoblasts. Odontoblasts and pulp tissue were cultured separately for 10 days in DMEM with 15% FBS containing additional glucose (G) (4.45 g/L) or insulin (I) (0.6 microgram/mL) or both together (GI). We evaluated type I collagen synthesis with RIA, measuring the level of N-terminal propeptide of type I collagen (PINP) secreted into the culture media. PINP secretion decreased in odontoblasts and pulp tissue in G and GI groups when compared with the control and insulin samples (p = 0.001 in both groups in the pulp samples). Insulin alone did not affect PINP secretion distinctly. The results indicate that high levels of glucose, but not insulin, directly down-regulate the type I collagen synthesis in young, differentiated human odontoblasts and pulp tissue. Insulin does not affect the inhibitory effect of high sucrose. These in vitro findings indicate that the high-sucrose diet may alter odontoblast function independently of insulin.

Human odontoblast culture method: the expression of collagen and matrix metalloproteinases (MMPs)

Studies on mature human odontoblasts have suffered for the lack of in vitro models. We recently introduced a human odontoblast and pulp tissue organ culture method, in which the odontoblasts are cultured in the pulp chamber after removal of the pulp tissue, and the pulp tissue can be cultured separately (Tjäderhane et al., 1998a). With this method, we have studied the effects of growth factors on the expression of collagen and extracellular matrix (ECM)-degrading enzymes, matrix metalloproteinases (MMPs), in mature human odontoblasts. TGF-beta 1 was selected because of its ability to regulate the response of the dentin-pulp complex to external irritation. The effect of TGF-beta 1 (10 ng/mL) on pro alpha 1(I) collagen mRNA was analyzed by quantitative PCR, and type I procollagen propeptide (PINP) was analyzed from conditioned culture media with RIA. Odontoblast media were also assayed for respective type III procollagen propeptide (PIIINP). TGF-beta had a negligible effect on collagen mRNA expression or protein synthesis, indicating that TGF-beta alone does not markedly induce dentin matrix formation per se in the human dentin-pulp complex (Palosaari et al., 2001). However, TGF-beta 1 seems to regulate MMP expression in mature human odontoblasts differentially. A strong down-regulation of MMP-8 (Palosaari et al., 2000), a modest down-regulation of MMP-20 (Tjäderhane et al., 2000), and considerable up-regulation of MMP-9, with no apparent effect on MMP-2 expression (Tjäderhane et al., 1998b), indicate that growth factors may affect the matrix synthesis by controlling the expression and activity of MMPs instead of collagen synthesis. The altered expression of MMPs may result in altered ECM formation, which in turn may contribute to the formation of atubular reparative dentin.

A combination of a chemically modified doxycycline and a bisphosphonate synergistically inhibits endotoxin-induced periodontal breakdown in rats

BACKGROUND

Chemically modified non-antimicrobial tetracyclines (CMTs) have been shown to inhibit pathologically elevated collagenase (and other matrix metalloproteinase, MMP) activity and bone resorption in vivo and in vitro.

METHODS

In the current study, suboptimal doses of CMT-8 (a non-antimicrobial chemically modified doxycycline) and a bisphosphonate (clodronate, an anti-bone resorption compound) were administered daily, either as a single agent or as a combination therapy, to rats with experimental periodontitis induced by repeated injection of bacterial endotoxin (LPS) into the gingiva. At the end of the 1-week protocol, the gingival tissues were dissected, extracted, and the extracts analyzed for MMPs (collagenases and gelatinases) and for elastase, and the defleshed jaws were morphometrically analyzed for alveolar bone loss.

RESULTS

LPS injection significantly (P<0.001) increased alveolar bone loss and increased collagenase (MMP-8), gelatinase (MMP-9), and elastase activities. Treatment of the LPS-injected rats with suboptimal CMT-8 alone or suboptimal clodronate alone produced slight reductions in the tissue-destructive proteinases and no significant reductions in alveolar bone loss. However, a combination of suboptimal CMT-8 and clodronate "normalized" the pathologically elevated levels of MMPs, elastase, and alveolar bone loss, indicating synergistic inhibition of tissue breakdown in this animal model of periodontitis.

CONCLUSIONS

Combination of a CMT and a bisphosphonate may be a useful treatment to optimally suppress periodontal destruction and tooth loss and in other tissue-destructive inflammatory diseases such as arthritis.

The levels of trypsinogen isoenzymes in ovarian tumour cyst fluids are associated with promatrix metalloproteinase-9 but not promatrix metalloproteinase-2 activation

Proteolysis mediated by matrix metalloproteinases (MMPs) and serine proteinases is associated with cancer invasion and metastasis. Activation of latent proMMPs, and especially the proforms of the type IV collagen degrading gelatinases A and B (proMMP-2 and proMMP-9), is thought to be a critical step in this process. We have recently found that human tumour-associated trypsin-2 is a potent activator of proMMP-9 and it also activates proMMP-2 in vitro. Trypsinogen, MMP-2, and MMP-9 are expressed in ovarian cancer. To elucidate the function of trypsin in vivo, we studied whether high concentrations of trypsinogen-1, trypsinogen-2, their alpha(1)-proteinase inhibitor (API) complexes, and tumour-associated trypsin inhibitor (TATI) are associated with proMMP-2 and proMMP-9 activation in ovarian tumour cyst fluids. Zymography and immunofluorometric analysis of 61 cyst fluids showed a significant association between high trypsin concentrations and the activation of MMP-9 (P = 0.003-0.05). In contrast, the trypsin concentrations were inversely associated with the activation of MMP-2 (P = 0.01-0.02). Immunohistochemical analysis of ovarian tumour tissue demonstrated expression of trypsinogen-2 and TATI in the secretory epithelium. MMP-2 was detected both in stromal and epithelial cells whereas MMP-9 was detected in neutrophils and macrophage-like cells in stromal and epithelial areas. These results suggest that trypsin may play a role in the regulation of the MMP-dependent proteolysis associated with invasion and metastasis of ovarian cancer.

In vivo collagenase-2 (MMP-8) expression by human bronchial epithelial cells and monocytes/macrophages in bronchiectasis

The purpose of this study was to determine whether other cellular sources than neutrophils can express matrix metalloproteinase (MMP)-8 protein and mRNA in bronchiectatic (BE) lung. The molecular forms of MMP-8 in the BE bronchoalveolar lavage fluid (BALF) and healthy control BALF were analysed by western immunoblotting. MMP-8 expression was demonstrated by immunohistochemistry and in situ hybridization in BE lung tissue and by immunohistochemistry in control lung tissue. In the BE BALF, different MMP-8 species were detected: 70-80 kD MMP-8 apparently of polymorphonuclear leukocyte (PMN) origin and also 40-60 kD MMP-8 from non-PMN cellular sources, such as bronchial epithelial cells, glandular cells or monocytes/macrophages. Both of these MMP-8 species were elevated and converted to a significant extent to activated forms in BE BALF compared with healthy control BALF. The levels of high molecular weight (>80 kD) MMP-8 complexes, evidently representing MMP-8 trapped by endogenous MMP inhibitors and/or MMP-8 dimers, were significantly elevated in BE BALF compared with healthy control BALF. In BE lung tissue, the MMP-8 protein and mRNA expression was found in bronchial ciliated epithelial cells, glandular cells, neutrophils, and monocytes/macrophages infiltrating the bronchial epithelial area. Minimal MMP-8 expression was observed in neutrophils, monocytes/macrophages, and epithelial cells in control lung tissues. In this study, new potential cellular sources have been demonstrated for MMP-8 in the inflamed lung. MMP-8 from multiple cellular sources, including inflamed lung epithelium, was activated to a significant extent in the BE BALF, indicating a major role for MMP-8 in the destruction of lung and bronchial tissues.

The effects of MMP inhibitors on human salivary MMP activity and caries progression in rats

Previous studies suggest that salivary and pulp-derived host enzymes, matrix metalloproteinases (MMPs), may be involved in dentin caries pathogenesis. To study the inhibition of acid-activated human salivary MMPs by non-antimicrobial chemically modified tetracyclines (CMTs), we used a functional activity assay with 125I-labeled gelatin as a substrate. To address the role of MMPs in the progression of fissure caries in vivo, we administered the MMP inhibitors CMT-3 and zoledronate to young rats per os for 7 weeks, 5 days a week. Caries lesions were visualized by Schiff reagent in sagittally sectioned mandibular molars. Marked reduction in gelatinolytic activity of human salivary MMPs was observed with CMT-3. CMT-3 and zoledronate, both alone and in combination, also reduced dentin caries progression in the rats. These results suggest that MMPs have an important role in dentin caries pathogenesis, and that MMP inhibitors may prove to be useful in the prevention of caries progression.

Expression and induction of collagenases (MMP-8 and -13) in plasma cells associated with bone-destructive lesions

Matrix metalloproteinases (MMPs) collectively degrade extracellular matrix and basement membrane proteins in chronic inflammation and bone-destructive lesions. This study examined the ability of immunoglobulin-producing plasma cells, typically present in sites of chronic inflammation, to express collagenases (MMP-8 and -13) in vivo and in vitro. Phorbol-12-myristate-13-acetate, interleukin-6, and tumour necrosis factor-alpha and heparin with the tumour promoter or cytokines potently enhanced (up to nine-fold) MMP-8 and -13 expression by the RPMI 8226 myeloma cell line, as evidenced by western blotting and semi-quantitative reverse transcriptase-polymerase chain reaction. Immunohistochemical analysis and in situ hybridization revealed that plasma cells expressed MMP-8 and -13 focally in periapical granulomas, odontogenic cysts, and malignant plasmacytomas. MMP-8 and MMP-13 from plasma cells can participate in bone organic matrix destruction at sites of chronic inflammation and neoplastic growth. Since MMP-13 was more frequently expressed than MMP-8 in plasma cells of strongly recurring keratocysts and malignant plasmacytomas, it is concluded that plasma cell MMP-13 has a particularly important role in benign and malignant bone-destructive lesions.

Matrix metalloproteinases in mild and severe temporomandibular joint internal derangement synovial fluid

OBJECTIVES

The first objective of this study was to verify the presence of and identify the molecular forms of matrix metalloproteinases (MMPs), including collagenases (MMP-1, MMP-8, and MMP-13) and gelatinases (MMP-2 and MMP-9), in the synovial fluid (SF) of mild and severe temporomandibular joint internal derangement (TMJ-ID). Another objective was to evaluate whether the SF MMPs are potential diagnostic markers that reflect the stage of intra-articular inflammation in the TMJ.

STUDY DESIGN

The subjects were 44 patients with mild (n = 16) or severe (n = 28) TMJ-ID; they were classified on the basis of subjective symptoms, clinical and radiographic findings, and surgical observations. The patients were surgically treated, and SF samples were collected immediately before the operation. The collagenase activity of SF samples was analyzed by means of a type I collagen degradation assay. The levels and molecular forms of the SF MMPs as well as the tissue inhibitors of MMPs (TIMP-1 and TIMP-2) were analyzed with Western immunoblotting and gelatin zymography.

RESULTS

The SF of both the mild and the severe TMJ-ID patients exhibited free collagenase activity and activity capable of further degrading the (3/4)(alphaA) fragments. Ninety-two-kilodalton proMMP-9 and its 121-kD complex form, as well as 72-kD proMMP-2 were significantly increased in the mild TMJ-ID group (P <.05 in all cases). Both 70- to 80-kD neutrophil type and 45- to 55-kD mesenchymal cell-type MMP-8 (corresponding to the latent and active forms) were observed in mild and severe TMJ-ID SF, but they predominated in mild TMJ-ID. Both MMP-1 and MMP-13 were observed in both groups, and in mild TMJ-ID SF the low-molecular weight forms of MMP-1 indicated activation of the enzyme.

CONCLUSIONS

The degradation of type I collagen in the TMJ is evidently due to the collective action of many collagenolytic MMPs present in the SF of patients with mild and severe TMJ-ID. The elevated levels of MMP-2, MMP-9, and MMP-8 in the SF of patients with mild TMJ-ID eventually reflect the active phase of TMJ destruction. These observations may have considerable diagnostic and therapeutic significance in the management of TMJ disorders.

CMT-3, a non-antimicrobial tetracycline (TC), inhibits MT1-MMP activity: relevance to cancer

Tetracyclines (TCs) and their non-antimicrobial analogs (CMTs) have therapeutic potential to inhibit tissue destructive disease processes, such as cancer invasion and metastasis, by inhibiting certain matrix metalloproteinases. Enhanced matrix metalloproteinase-2 (MMP-2; gelatinase A) activity has been correlated to cancer invasiveness, and membrane type MMP (MT1-MMP) expressed by tumor cells is involved in localizing and activating pro-MMP-2, a pathway believed to mediate cancer induced tissue breakdown. CMT-3 (6-demethyl, 6-deoxy, 4-dedimethylamino TC) has been shown to experimentally suppress prostate cancer, colon adenocarcinoma and melanoma invasiveness in cell culture and to inhibit tumor growth and metastasis in vivo and was used in the current in vitro study. Confluent MT1-MMP transfected COS-1 cells were harvested, washed thoroughly, subjected to N(2) cavitation and cell membrane enriched fractions were isolated by sequential centrifugations. This MT1-MMP preparation exhibited (i) pro-MMP-2 activating activity as shown by molecular weight shift of this gelatinase from 72 kDa to 62 kDa using gelatin zymography, and (ii) the ability to degrade both [(3)H-methyl] gelatin and casein at 37 degrees C. Adding CMT-3 at final concentrations of 5--20microM inhibited MT1-MMP gelatinolytic and caseinolytic activity, blocked MT1-MMP activation of pro-MMP-2, and decreased invasiveness (using the Matrigel system) of HT-1080 fibrosarcoma cells. The inhibition of MT1-MMP by CMT-3 may partially explain the inhibition of cancer cell -mediated tissue breakdown and invasiveness by this non-antimicrobial tetracycline analog.