Inhibition of matrix metalloproteinase-1 by dichloromethylene bisphosphonate (clodronate)

Interstitial collagenase present in human jaw cyst extract and purified human fibroblast-type collagenase (MMP-1) were both efficiently inhibited in vitro by clodronate, an osteoactive, antiresorptive bisphosphonate. The IC50 of clodronate to inhibit MMP-1 is 150 microM. These findings suggest an extended and hitherto undescribed properties for clodronate/biphosphonates in prevention and treatment of tissue degradation in both bone and soft tissue destructive diseases.

Collagenolytic activity and its sensitivity to doxycycline inhibition in tracheal aspirates of horses with chronic obstructive pulmonary disease

The collagenolytic activity and its sensitivity to doxycycline inhibition in tracheal aspirates (TA) of horses with chronic obstructive pulmonary disease (COPD) was analyzed with SDS-PA gel electrophoresis (SDS-PAGE), using Type 1 collagen as the substrate. Both autoactive and total collagenase activities were significantly higher in TAs of horses with symptomatic COPD than in TAs of healthy horses. Doxycycline inhibition studies suggest that most of the TA collagenase is of the neutrophil type (MMP-8), but some is derived from other cells such as fibroblasts and monocyte/macrophages (MMP-1) and bacteria (bacterial collagenases). Drugs inhibiting collagenases in the respiratory tract might be worth a trial in the treatment of COPD in horses.

Gelatinolytic activity in tracheal aspirates of horses with chronic obstructive pulmonary disease

The gelatinolytic activity in tracheal aspirates (TA) of horses with chronic obstructive pulmonary disease (COPD) was analyzed using SDS-PAGE-gelatin-gel electrophoresis (zymography) and compared to TAs from healthy controls. The 110-90 kD MMP-9 type gelatinase was high in symptomatic disease phases (permanent disease 0.46 +/- 0.15, p < 0.001; or intermittent disease 0.47 +/- 0.12, p < 0.001) compared to healthy controls (0.10 +/- 0.07). Similarly, the overall gelatinolytic activity, the activity in high-mw gelatinolytic bands (210-190 and 150 kD) and in proteolytically processed fragments in the 50-40 kD range were high, whereas the 75-65 kD MMP-2 was not altered. These findings suggest that MMP-9 type gelatinases, originating possibly from neutrophils or macrophages, and products thereof have a role in the pathogenesis of equine respiratory diseases, whereas MMP-2 type gelatinases represent house-keeping proteinases involved with normal tissue remodelling. The gelatinolytic activity in TAs correlated with the beta-glucuronidase activity, which indicates that they are simultaneously elevated in the respiratory secretions of horses suffering from COPD and might both be of same origin, or have a causal relationship.

Macrophage-colony stimulating factor (M-CSF) is increased in the synovial-like membrane of the periprosthetic tissues in the aseptic loosening of total hip replacement (THR)

The aim of the study was to assess the eventual presence, cellular localization and extent of expression of the osteoclast activating cytokine M-CSF (CSF-1) in the periprosthetic tissues around loose total hip replacement (THR). Synovial-like membrane was obtained from the implant-to-bone interface and pseudocapsule from ten total hip revisions performed for aseptic loosening and compared to ten hip synovial tissue samples obtained from ten patients who had primary THR for osteoarthritis. Avidin-biotinperoxidase complex (ABC) and alkaline phosphatase-anti-alkaline phosphatase (APAAP) methods were used for staining and VIDAS image analysis for quantification. M-CSF was mainly produced by macrophages, which often contained wear particles, but also by some fibroblasts and vascular endothelial cells. The number of cells containing (per one mm2 tissue) clearly increased in the interface (1585 +/- 212; p < 0.01) and pseudocapsular (1456 +/- 248; p < 0.01) tissue compared to synovial tissue (543 +/- 118). The present findings suggest, that inflammatory foreign-body type of response enhances expression of M-CSF in cases of aseptic loosening of THR. M-CSF produced in the synovial-like membrane in the implant-bone interface may contribute to activation of osteoclasts in periprosthetic bone and thus to loosening.

ASEPTIC LOOSENING OF TOTAL HIP REPLACEMENT

Aseptic loosening is a major cause of failure of total hip arthroplasty. The adverse tissue response to prosthetic wear particles, with activation of cytokine and prostanoid production, contributes to bone loss around the implants. We have investigated the possibility that inducible nitric oxide synthase (iNOS) and cyclo-oxygenase-2 (COX-2) are expressed in macrophages in the pseudomembrane at the bone-implant interface, thereby contributing to the periprosthetic bone resorption.

We also assessed whether peroxynitrite, a nitric oxide (NO)-derived oxidant associated with cellular injury, is generated in the membrane. Enzymatic activity of iNOS was measured using the arginine-citrulline assay technique and prostaglandin E2 (PGE2), as an indicator of COX-2 activity, was measured using an enzyme immunoassay.

Cellular immunoreactivity for iNOS, nitrotyrosine (a marker of peroxynitrite-induced cellular injury) and COX-2 was assessed by quantitative peroxidase immunocytochemistry while immunofluorescence methods were used for subsequent co-localisation studies with CD68+ macrophages.

The presence of calcium-independent iNOS activity and PGE2 production was confirmed in the homogenized interface membrane. Immunocytochemistry showed that periprosthetic CD68+ wear-debris-laden macrophages were the most prominent cell type immunoreactive for iNOS, nitrotyrosine and COX-2. Other periprosthetic inflammatory and resident cell types were also found to immunolocalise nitrotyrosine thereby suggesting peroxynitrite-induced protein nitrosylation and cellular damage not only in NO-producing CD68+ macrophages, but also in their neighbouring cells. These data indicate that both iNOS and COX-2 are expressed by CD68+ macrophages in the interface membrane and peroxynitrite-induced cellular damage is evident in such tissue. If high-output NO and peroxynitrite generation were to cause macrophage cell death, this would result in the release of phagocytosed wear debris into the extracellular matrix. A detrimental cycle of events would then be established with further phagocytosis by newly-recruited inflammatory cells and subsequent NO, peroxynitrite and prostanoid synthesis. Since both NO and have been implicated in the induction and PGE2 maintenance of chronic inflammation with resulting loss of bone, and peroxynitrite in the pathogenesis of disease states, they may be central to the pathogenesis of aseptic loosening.

Aseptic loosening of total hip replacement. Macrophage expression of inducible nitric oxide synthase and cyclo-oxygenase-2, together with peroxynitrite formation, as a possible mechanism for early prosthesis failure

Aseptic loosening is a major cause of failure of total hip arthroplasty. The adverse tissue response to prosthetic wear particles, with activation of cytokine and prostanoid production, contributes to bone loss around the implants. We have investigated the possibility that inducible nitric oxide synthase (iNOS) and cyclo-oxygenase-2 (COX-2) are expressed in macrophages in the pseudomembrane at the bone-implant interface, thereby contributing to the periprosthetic bone resorption. We also assessed whether peroxynitrite, a nitric oxide (NO)-derived oxidant associated with cellular injury, is generated in the membrane. Enzymatic activity of iNOS was measured using the arginine-citrulline assay technique and prostaglandin E2 (PGE2), as an indicator of COX-2 activity, was measured using an enzyme immunoassay. Cellular immunoreactivity for iNOS, nitrotyrosine (a marker of peroxynitrite-induced cellular injury) and COX-2 was assessed by quantitative peroxidase immunocytochemistry while immunofluorescence methods were used for subsequent co-localisation studies with CD68+ macrophages. The presence of calcium-independent iNOS activity and PGE2 production was confirmed in the homogenised interface membrane. Immunocytochemistry showed that periprosthetic CD68+ wear-debris-laden macrophages were the most prominent cell type immunoreactive for iNOS, nitrotyrosine and COX-2. Other periprosthetic inflammatory and resident cell types were also found to immunolocalise nitrotyrosine thereby suggesting peroxynitrite-induced protein nitrosylation and cellular damage not only in NO-producing CD68+ macrophages, but also in their neighbouring cells. These data indicate that both iNOS and COX-2 are expressed by CD68+ macrophages in the interface membrane and peroxynitrite-induced cellular damage is evident in such tissue. If high-output NO and peroxynitrite generation were to cause macrophage cell death, this would result in the release of phagocytosed wear debris into the extracellular matrix. A detrimental cycle of events would then be established with further phagocytosis by newly-recruited inflammatory cells and subsequent NO, peroxynitrite and prostanoid synthesis. Since both NO and PGE2 have been implicated in the induction and maintenance of chronic inflammation with resulting loss of bone, and peroxynitrite in the pathogenesis of disease states, they may be central to the pathogenesis of aseptic loosening.

Role of nitric oxide in Sjögren's syndrome

OBJECTIVE

To measure levels of salivary nitrite (NO2-) and to localize nitric oxide synthases (NOS) in the labial salivary glands (LSGs) of patients with Sjögren's syndrome (SS).

METHODS

NO2- was measured by the Griess reaction. LSGs were analyzed using NADPH-diaphorase histochemical and immunohistochemical studies to determine the constitutive NOS (neuronal [ncNOS] and endothelial [ecNOS]) and inducible NOS (iNOS) isoforms.

RESULTS

The NO2- concentration (mean +/- SEM 307 +/- 51 microM versus 97 +/- 16 microM; P < 0.05) and output (166 +/- 46 nmoles/minute versus 37 +/- 7 nmoles/minute) were increased in SS patients compared with healthy control subjects. NADPH-diaphorase was found in some nerve fibers and endothelial cells, and, in SS, was found in myoepithelial, acinar, and ductal epithelial cells, but in only a few inflammatory cells. In SS, ncNOS-immunoreactive nerve fibers were sparse and ecNOS was found in a minority of the CD31-positive vascular endothelial cells and acinar cells, whereas iNOS was localized in myoepithelial, acinar, and ductal epithelial cells, often together with tumor necrosis factor alpha.

CONCLUSION

Nitrite was found in normal human saliva. NO produced by ncNOS probably acts as a nonadrenergic, noncholinergic neurotransmitter, whereas that produced by ecNOS exerts a vasodilatory effect. SS patients had increased NO2- concentrations, with most of the superfluous salivary NO being produced not by the immigrant inflammatory cells, but rather, by the resident salivary gland cells. NO may contribute to inflammatory damage and acinar cell atrophy in SS.

Transforming growth factor-beta 1 and 2 in the synovial-like interface membrane between implant and bone in loosening of total hip arthroplasty

OBJECTIVE

Development of a synovial-like membrane in the implant-bone or cement-bone interface has been linked to aseptic loosening of total hip arthroplasties (THA). This tissue consists of a fibrous stroma containing blood vessels and macrophages, but with relatively few lymphocytes, compared to "autoimmune" rheumatoid synovitis. Our aim was to examine transforming growth factor-beta (TGF-beta) in the synovial-like membrane of the interface and pseudocapsular tissue of loose THA and compare it to control knee synovial membrane.

METHODS

Twenty samples obtained from 10 patients with loose THA at revisions performed for aseptic loosening and 10 samples of knee synovial membrane as controls were analyzed for TGF-beta expression using rabbit antihuman TGF-beta 1 and TGF-beta 2 IgG in immunohistochemical staining. Results were quantitated by a semi-automatic VIDAS image analysis system.

RESULTS

Immunoperoxidase staining disclosed TGF-beta in macrophages and fibroblasts and also in some vascular endothelial cells and in occasional lymphocytes. Image analysis showed an increased number of positive cells/mm2 of both TGF-beta 1 (2327 +/- 212 vs 946 +/- 136; p < 0.01) and TGF-beta 2 (2292 +/- 594 vs 311 +/- 113; p < 0.01) compared to the control tissue. Increased expression of both TGF-beta 1 and TGF-beta 2 was also shown in the pseudocapsule (3210 +/- 585 and 1796 +/- 214). Use of cement or type of alloy did not seem to have any great effect on local expression of TGF-beta.

CONCLUSION

Profibrotic and immunosuppressive TGF-beta are increased in the synovial-like membrane in periprosthetic tissues around loose hip prostheses. They may play a role in the formation, maintenance, and growth of the interface tissue, and thus in the aseptic loosening of THA.

Tear fluid plasmin activity of dry eye patients with Sjögren's syndrome

Thirty-two eyes of 16 patients with verified Sjögren's syndrome were examined for clinical signs of dry eye. Tear fluid samples were collected for plasmin assay. Ophthalmologic examinations included estimation of conjunctival or corneal discharge, filament formation and presence of conjunctival or corneal epithelial defects, assessment of tear meniscus height and measurement of tear fluid break-up time, Schirmer test, and fluorescein and Rose-Bengal staining graded by the van Bijsterveld score. Tear fluid plasmin activity (IU/l) was determined by a fluorometric assay and tear fluid flow (microl/min) was measured for calculation of tear fluid plasmin activity release (microIU/min). All patients had relatively dry eyes; the mean Schirmer test value was 5.7 +/- 0.5 mm/5 min. The mean tear fluid break-up time was also low, 7.7 +/- 0.5 s. The mean Bijsterveld score value was 2.5 +/- 0.5. Because collection of tear fluid by microcapillaries for the plasmin assay was difficult due to the low tear fluid flow rate, it was necessary to drop 20 microl of balanced salt solution topically on the cornea to aspirate a tear fluid sample. Despite this, the mean tear fluid plasmin activity was higher than in control individuals (7.75 +/- 1.51 IU/l vs. 0.73, range 0.64-0.80 IU/l). On the basis of these findings we conclude that elevated tear fluid proteolytic activity may play a role in the pathology of dry eye/ocular surface disease.

Tyrosine hydroxylase-immunoreactive nerve fibres in rat posterior longitudinal ligament

The nerve supply to the posterior longitudinal ligament (PLL) of the lumbar vertebrae has been the focus of considerable interest to gain insight into the pathogenesis of low back pain. The present study aimed to characterize the sympathetic fibres in the PLL by immuno-electronmicroscopy for tyrosine hydroxylase (TH), the rate limiting enzyme in catecholamine synthesis. The posterior central branches of the segmental lumbar arteries received numerous communicating fibres from the sinuvertebral nerve (SVN), but only shortly after their entrance to the spinal canal. The non-vessel-associated branches of the SVN formed transverse bundles, which met fibres from the opposite side in a plexus-like mid-sagittal network. As these fibres approached the midline, they gradually lost their Schwann cell cover. The free and naked fibres contained numerous terminal-like varicosities. The TH-ir and 6-hydroxydopamine (6-OH-DA) sensitive fibres were intermingled with non-TH-ir fibres. The TH-ir sympathetic fibres had no obvious target structures except for the numerous, intermingled, closely related and communicating terminal-like axons in the mid-sagittal network in contact with non-TH-ir fibres. This may represent a neuroanatomical equivalent reflecting modulatory functions, which could participate in the pathogenesis of low back pain.

Salivary mucous glycoprotein MG1 in Sjögren's syndrome

The aim of the study was to develop and apply a rapid method for the simultaneous analysis of the concentration and molecular weight of the human high-molecular weight mucin MG1 in small volumes of unprocessed saliva from healthy controls and from patients with Sjögren's syndrome (SS). In high performance liquid chromatography (HPLC) with a TSK 5000 PW size exclusion column, MG1 eluted with a retention time 10.6 min corresponding to a M(r) of 2 to 2.5 x 10(6). Molecular weight changes under various experimental conditions are compatible with the suggestion that the MG1 complex is composed of four 660 x 10(3) glycosylated subunits connected by disulphide bridges and associated with a 25-35 x 10(3) Da link protein. In SS the molecular weight of MG1 was normal and its concentration was high in resting (190 vs. 70 micrograms/ml, P = 0.001) but not in stimulated (46 vs. 48 micrograms/ml, P > 0.05) saliva; MG1 concentration in resting SS saliva did not vary in parallel with protein and the interindividual differences were considerable. Size exclusion HPLC is a rapid and reproducible method suitable for isolation and analysis of salivary MG1 from small volumes of unprocessed samples. The molecular weight or subunit structure of MG1 were not altered in SS. The high concentration of MG1 in resting saliva in SS, may be explained by the concentration effect, or alternatively by the low water retaining capacity, which may play an important pathogenic role in xerostomia of SS.

Collagenolytic activity and its sensitivity to doxycycline inhibition in tracheal aspirates of horses with chronic obstructive pulmonary disease

The collagenolytic activity and its sensitivity to doxycycline inhibition in tracheal aspirates (TA) of horses with chronic obstructive pulmonary disease (COPD) was analyzed with SDS-PA gel electrophoresis (SDS-PAGE), using Type 1 collagen as the substrate. Both autoactive and total collagenase activities were significantly higher in TAs of horses with symptomatic COPD than in TAs of healthy horses. Doxycycline inhibition studies suggest that most of the TA collagenase is of the neutrophil type (MMP-8), but some is derived from other cells such as fibroblasts and monocyte/macrophages (MMP-1) and bacteria (bacterial collagenases). Drugs inhibiting collagenases in the respiratory tract might be worth a trial in the treatment of COPD in horses.

Gelatinolytic activity in tracheal aspirates of horses with chronic obstructive pulmonary disease

The gelatinolytic activity in tracheal aspirates (TA) of horses with chronic obstructive pulmonary disease (COPD) was analyzed using SDS-PAGE-gelatin-gel electrophoresis (zymography) and compared to TAs from healthy controls. The 110-90 kD MMP-9 type gelatinase was high in symptomatic disease phases (permanent disease 0.46 +/- 0.15, p < 0.001; or intermittent disease 0.47 +/- 0.12, p < 0.001) compared to healthy controls (0.10 +/- 0.07). Similarly, the overall gelatinolytic activity, the activity in high-mw gelatinolytic bands (210-190 and 150 kD) and in proteolytically processed fragments in the 50-40 kD range were high, whereas the 75-65 kD MMP-2 was not altered. These findings suggest that MMP-9 type gelatinases, originating possibly from neutrophils or macrophages, and products thereof have a role in the pathogenesis of equine respiratory diseases, whereas MMP-2 type gelatinases represent house-keeping proteinases involved with normal tissue remodelling. The gelatinolytic activity in TAs correlated with the beta-glucuronidase activity, which indicates that they are simultaneously elevated in the respiratory secretions of horses suffering from COPD and might both be of same origin, or have a causal relationship.

Complement in acute and chronic arthritides: assessment of C3c, C9, and protectin (CD59) in synovial membrane

OBJECTIVES

To investigate the role of complement cascade induced damage and protection against it in acute arthritides compared to rheumatoid arthritis and other chronic joint derangements.

METHODS

C3c, C9, and protectin (CD59) were examined by avidin-biotin-peroxidase complex staining.

RESULTS

Marked deposits of C3c and C9 were found in synovial vasculature and intercellular matrix of the lining in rheumatoid arthritis and in acute arthritides (including bacterial, reactive, and osteoarthritis flare up). Furthermore, protectin was not visible in synovial lining cells and was relatively weakly expressed in stromal and endothelial cells in rheumatoid arthritis; also in acute arthritides protectin expression was weak. In contrast, C3c and C9 deposits were not found in chronic conditions associated with degenerative diseases (osteoarthritis and osteochondritis dissecans) or mechanical causes (patellar luxation and a ruptured meniscus), in which also the protectin expression was prominent in synovial lining, endothelial and some stromal cells.

CONCLUSIONS

Activation of the complement in rheumatoid arthritis and in acute arthritides seems to be associated with a decreased protection of synovial cells against cellular effects and lysis mediated by membrane attack complex.

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.

Matrix metalloproteinases-1, -3 and -8 and myeloperoxidase in saliva of patients with human immunodeficiency virus infection

OBJECTIVE

Human immunodeficiency virus (HIV)-seropositive patients have frequently severe gingival inflammation and/or attachment loss. In addition many infectious diseases affect their periodontium with varying clinical manifestations. Matrix metalloproteinases seem to play a key role in physiological periodontal remodelling and pathological tissue destruction. The aim of the present study was to characterize the presence, molecular forms, cellular sources, activities, and relative amounts of fibroblast-type (matrix metalloproteinase [MMP]-1) and neutrophil (MMP-8) collagenases, as well as their potential activator stromelysin-I (MMP-3) and myeloperoxidase in saliva of HIV-seropositive patients at different phases of HIV-infection. HIV-seronegative, healthy, age-matched patients served as controls.

PATIENTS AND METHODS

Saliva samples were characterized by Western blotting using antibodies specific for MMP-1, MMP-3 and MMP-8. Interstitial collagenase activities were measured using quantitative sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis/laser densitometry assay. Myeloperoxidase was analysed using quantitative dot blotting.

RESULTS

Clinical and microbiological evaluation of HIV-seropositive patients' periodontium showed the presence of putative periodontopathogens ie Actinobacillus actinomycetemcomitans (Aa), Porphyromonas gingivalis (Pg), Prevotella intermedia (Pi), Peptostreptococcus micros (Psm) and Campylobacter rectus (Cr) in their periodontal pockets. The amount of Candida increased with the severity of HIV-infection. Clinical and microbiological findings of HIV-seropositive patients suggested that they have a tendency to develop periodontal disease. Interstitial collagenase activities were found to be increased in saliva of different phases of HIV-infected patients compared to the controls. Independent of the phase of HIV-infection saliva samples contained pro- and active forms of MMP-1, -3 and -8 using Western blotting. Saliva samples from healthy controls were found to contain hardly any immunoreactivities for MMP-1 or MMP-8, but considerable amounts of MMP-3 were detected. Quantitative dot blotting demonstrated increased amounts of myeloperoxidase in HIV-patients' saliva relative to controls.

CONCLUSION

The present results showed increased amounts of MMP-1, -3, -8 and myeloperoxidase in HIV-patients' saliva. MMP-1 and -8 may have been activated by MMP-3 and/or oxidants generated by myeloperoxidase. The increased amounts of MMPs and myeloperoxidase may reflect and directly participate in HIV-infection associated periodontitis.

Membrane components of Treponema denticola trigger proteinase release from human polymorphonuclear leukocytes

Tissue destruction during periodontitis is believed to be primarily brought about by leukocyte proteinases. We postulate that oral spirochetes cause discharge of polymorphonuclear leukocyte (PMN) lysosomal enzymes. Effects of Treponema denticola 53-kDa outer membrane protein, lipopolysaccharide (LPS), and peptidoglycan on degranulation of matrix metalloproteinases (MMP)-8 (collagenase) and -9 (gelatinase), cathepsin G, and elastase by human peripheral blood PMNs were studied by specific enzyme assays and Western blot analysis. T. denticola 53-kDa kDa outer membrane protein was found to be a particularly efficient inducer of MMP-8 release. The induction was comparable with that of phorbol myristate acetate, a known inducer of PMN specific granule discharge. All of the treponemal substances, most notably the 53-kDa protein and LPS, induced release of MMP-9, a component of C-type granules. Both collagenase and gelatinase released from PMNs were mostly in active forms. Release of cathepsin G and elastase was also observed with the 53-kDa protein treatment. The other T. denticola substances did not induce release of these serine proteinases. Lactate dehydrogenase was not released from PMNs by the treatments, indicating that the degranulation was specific and not caused by toxic effects of the substances. This was confirmed by transmission electron microscopy of PMNs treated with the 53-kDa protein that showed rapid vacuole formation and cell shape changes but no disintegration of the cells. Thus, T. denticola may participate in the PMN-dependent extracellular matrix degradation during the course of periodontal inflammation by triggering the secretion and activation of matrix metalloproteinases.

Aberrant vascularity and von Willebrand factor distribution in inflamed synovial membrane

OBJECTIVE

Von Willebrand factor (vWF) is an adhesive glycoprotein produced and secreted constitutively by endothelial cells. vWF is released upon endothelial stimulation and/or vascular injury, and mediates adhesion and aggregation of platelets. Our aim was to quantify synovial vasculature and to evaluate vWF distribution in situ in synovial membranes in various arthritides.

METHODS

Immunohistochemical staining of vWF in synovial membranes from patients with rheumatoid arthritis (RA) (N = 9), psoriatic (PsA) (N = 3), and reactive (ReA) (N = 4) arthritis, and from 6 noninflammatory controls: osteoarthritis (N = 1), chondromatosis (N = 1), meniscus lesion (N = 4). Morphometric assessments were performed with an image analyzer.

RESULTS

In RA, mean number of blood vessels/mm2 in the thickened synovium was relatively low (131 +/- 57 vs control 257 +/- 115, p = 0.0137, ReA 346 +/- 83, p = 0.0002, PsA 434 +/- 157, p = 0.0127). In particular, the superficial layer, corresponding to the thickness of normal synovial membrane (i.e., 56 +/- 5 microns), was sparsely vascularized (70 +/- 37 in the superficial vs 219 +/- 104 in the deeper layer, p = 0.0047). Synovial thickening was not seen in ReA and PsA. In accordance with its constitutive metabolism, vWF was found in the endothelial cells, inside the blood vessels, and in the subendothelium. In addition, RA was characterized by weak endothelial immunoreactivity and perivascular vWF. In ReA, perivascular vWF staining was visible in areas of inflammatory cell infiltrates.

CONCLUSION

Morphometric findings indicate decreased vascularization of the superficial synovial membrane in RA. Second, vWF may play a role in the inflammatory/reparative responses in synovium in RA and ReA, which were characterized by vascular stimulation/injury and abnormal vWF distribution.

Tumor necrosis factor-alpha (TNF-alpha) in loosening of total hip replacement (THR)

OBJECTIVE

The initially well-fixed implants of total hip replacement (THR) are in the long-term subject to aseptic loosening. Many cytokines can contribute to osteolysis due to osteoclast recruitment and/or activation. However, in this respect tumor necrosis factor-alpha (TNF-alpha) plays a pivotal role, because it upregulates interleukin-1 and 6 and granulocyte-macrophage colony stimulating factor. The aim of this study was to assess the eventual presence, cellular localization and extent of expression of TNF-alpha in the synovial-like membrane at the implant or at the cement to bone interface compared to control synovial membrane.

METHODS

Twenty samples from the synovial-like membrane of the periprosthetic tissues were compared to control samples. TNF-alpha containing cells were visualized using an avidin-biotin-peroxidase complex (ABC) method and analyzed by light microscopy, double labelling and image analysis.

RESULTS

TNF-alpha was found in the periprosthetic tissues in fibroblasts and vascular endothelial cells, but mainly in the macrophages was it found to coincide with areas containing implant-derived debris. TNF-alpha containing cells were more numerous in the synovial-like membrane in the interface tissue from the proximal stem area (2816 +/- 318 cells) than in the control synovial membrane (565 +/- 93 cells, p < 0.01). Interestingly, similarly high TNF-alpha expression (3452 +/- 582 cells) was also seen in the synovial-like membrane of the pseudocapsule.

CONCLUSION

These findings suggest that the foreign body-type host reaction caused by THR is characterized by the high expression of TNF-alpha. Because such expression occurred in the interface tissue between the implant and surrounding bone, TNF-alpha, due to its pivotal direct and indirect role in the activation and recruitment of osteoclasts, may contribute to periprosthetic osteolysis and to the loosening of THR.

Sense of coherence and outcome of low-back surgery: 5-year follow-up of 80 patients

Eighty adult patients, 33 men and 47 women, mean age 46 years (SD 11.8, range 19-74 years), were evaluated 5 years after low-back surgery. The mean duration of symptoms before operation was 8.7 (SD 7.1) years. The purpose was to evaluate the 5-year outcome of low-back surgery, to find the best predictors for the outcome, and to find out if a correlation exists between the patient's sense of coherence and the outcome of low-back surgery. The mean Oswestry pain index for the whole group of patients improved from 3.8 to 2.7 (P < 0.001). The greatest improvement in pain was found in the group aged 35-50 years. In those over 50 years old, pain improved significantly more in women than men. Regarding walking ability, the mean Oswestry gait index for the whole group improved from 3.0 to 1.9 (P < 0.001), with men over 50 years old achieving the greatest improvement in their walking. The mean Oswestry total index for the whole group was 41% before surgery, reflecting severe disability, and 25% at follow-up, reflecting moderate disability (P < 0.001). There was no difference between the mean values for men and women. Patients who had undergone several previous operations fared less well in the Oswestry total index, though their improvement was still significant (P < 0.05). The postoperative Oswestry total index values correlated significantly with the sense of coherence (SOC) scale values (r = -0.23, P < 0.05). In all patients, the Oswestry total index before the index operation is suggested to be a predictor of the final outcome. In multiple regression analysis, the number of previous operations and the preoperatively recorded Oswestry total index appeared to be the best predictors for outcome of low-back surgery. We also found that the SOC scale correlated significantly with the Oswestry total index and seems to provide a possible explanation of ability to cope with the disability and pain associated with low-back disorders.

Human neutrophil gelatinase and associated lipocalin in adult and localized juvenile periodontitis

In search of direct in vivo evidence of matrix metalloproteinases (MMPs) in periodontal tissue destruction, we studied the presence and localization of MMP-9 and neutrophil gelatinase-associated lipocalin (NGAL) in adult periodontitis (AP) and localized juvenile periodontitis (LJP) gingival tissue specimens by immunohistochemistry, and the activities of gelatinases by Western blot, enzymography, and activity measurements, using radioactive gelatin as substrate in gingival crevicular fluid (GCF) and saliva. In gingival tissue obtained from AP and LJP patients, polymorphonuclear leukocyte (PMN) 92-kDa MMP-9 and NGAL were seen in the connective tissue, but both the sulcular and the oral epithelia were consistently negative. Whereas PMNs located in the gingival blood vessels showed strictly cytoplasmic MMP-9 and NGAL immunoreactivities, in the case of PMN extravasation the staining reactions extended extracellularly. Gelatinase activities consisting mainly of 92-kDa gelatinase were increased in AP GCF relative to LJP GCF and periodontally healthy control GCF. Western blot with specific anti-NGAL antibodies revealed the presence of 25-kDa NGAL and its high-molecular-weight forms in AP and LJP GCF and saliva and in culture medium of oral keratinocytes, but not in gingival fibroblast culture medium. We conclude that extravasated degranulating PMNs are the major source of MMP-9 and NGAL in periodontitis gingiva, GCF, and saliva.

Neutral endopeptidase (EC 3.4.24.11) in labial salivary glands in healthy controls and in patients with Sjögren's syndrome

OBJECTIVE

Neuropeptides from nerve fibres can cause neurogenic inflammation. The potency of these peptides in vitro has led to the hypothesis that enzyme degradative systems are operative in vivo to limit their action. To consider this question neutral endopeptidase (NEP) in labial salivary glands in patients with Sjögren's syndrome was studied.

METHODS

Synthesis of NEP mRNA in situ in labial salivary glands was studied using the reverse transcriptase polymerase chain reaction (RT-PCR). Immunohistochemical staining was used to localise the NEP enzyme protein and its neuropeptide substrates and fluorophotometry to measure the corresponding enzyme activities in saliva.

RESULTS

NEP was found in nerve fibres and in perivascular, periductal, and periacinar axon terminal varicosities. Double labelling of PGP 9.5 and NEP confirmed this neuronal localisation of NEP. Although some fibroblast-like cells and occasional intravascular neutrophils were NEP positive, NEP mRNA was not found in labial salivary glands. Patients with Sjögren's syndrome and healthy controls did not have nerves containing NEP or neuropeptides (vasoactive intestinal peptide, substance P, or calcitonin gene related peptide (CGRP)) in lymphocyte foci. Salivary NEP activity was not decreased in patients compared with controls.

CONCLUSION

NEP in labial salivary glands is almost totally of neuronal origin and plays a part in proteolytic modulation of neuropeptides in salivary glands and saliva. These regulatory interactions seem to be altered in focal lymphocyte accumulations in Sjögren's syndrome.

Characterization of matrix metalloproteinase (MMP-8 and -9) activities in the saliva and in gingival crevicular fluid of children with Down's syndrome

Previous studies have shown increased susceptibility to periodontal diseases in children with Down's syndrome (DS). The mechanisms involved in the periodontal inflammatory processes in DS are not fully understood. The present study characterized the periodontal status of 9 non-institutionalized DS children 9 to 17 years old (mean 13.6 years) relative to their age-matched systemically and periodontally healthy controls. The periodontal status was assessed by visible plaque index (VPI), gingival bleeding index (GBI), and probing depth. We also assessed, by sodium dodecyl sulphate polyacrylamide gel electrophoresis/laser densitometry and by zymography, the collagenase and gelatinase activities in the gingival crevicular fluid (GCF) and saliva samples collected from DS patients and from the controls. Eight of the nine DS children showed a periodontium comparable to that seen in healthy controls; beginning alveolar bone loss was radiographically seen in the DS patient with deep periodontal pockets. The endogenously active collagenase and total collagenase activities were slightly higher in GCF of DS children compared to healthy controls. Western blot demonstrated that GCF collagenase of DS patients was human neutrophil collagenase (MMP-8 or collagenase-2), which occurred in 75 kDa proMMP-8 and in DS patients, but not in controls, also in 65 kDa active MMP-8 form and occasionally lower 40-50 kDa MMP-8 species. Zymographic analysis revealed the presence of 120 kDa (MMP-9 complexed with neutrophil gelatinase associated lipocalin or NGAL), 92 kDa (MMP-9) and 72 kDa (MMP-2) gelatinases in DS and control GCF. Especially in DS GCF MMP-9 occurred in part in 82-85 kDa activated form. Salivary collagenase in DS was high when compared to controls but of the same MMP-8 type as in control saliva. Our findings suggest that in vivo activated MMP-8 in GCF derived from triggered PMNs and/or cytokine-induced periodontal fibroblasts may reflect periodontal tissue and alveolar bone destruction seen in the early stages of gingivitis/periodontitis associated with Down's syndrome.

Human monocytes stimulation by particles of hydroxyapatite, silicon carbide and diamond: in vitro studies of new prosthesis coatings

Aseptic loosening due to wear and debris formation constitutes the major problem in longevity of joint replacements. Diamond coated onto the prosthesis surface may reduce wear, owing to its excellent tribological properties. A thin diamond coating may be brittle, and we plan eventually to reinforce it with silicon carbide whiskers (SiC). In the present study we compared particles of diamond, SiC and hydroxyapatite (HA) in serum-free cultures of human monocytes. All particles were found to be phagocytozed, and monocyte morphology changed except after the ingestion of diamond. Interleukin-1 beta production was increased on average 30-fold and 38-fold in cultures exposed to HA and SiC, respectively, compared to control and diamond cultures (n = 6). Addition of the phagocytosis inhibitor cytochalasin B inhibited the morphological changes of the monocytes and reduced interleukin-1 beta production. In some experiments particles of polymethylmethacrylate were also included, and the interleukin-1 beta stimulation was in the same range as after HA and SiC stimulation. The results show that diamond particles in serum-free monocyte culture are inert, while SiC and HA have a stimulatory effect comparable to polymethylmethacrylate. With its excellent tribological and biocompatible properties, future studies with diamond coating are warranted.