The effect of interleukin-1 β on hyaluronic acid synthesized by adult human gingival fibroblasts in vitro

The effect of recombinant interleukin-1β (IL-lβ) on hyaluronic acid synthesis by human gingival fibroblasts was studied. IL-1bT caused a dose-dependent increase in the incorporation of (³lucosamine into hyaluronic acid. The ³⁵S/35H ratios of labeled macromolecules did not change regardless of the presence or absence of TL-lβ and indicates stimulation of hyaluronic acid synthesis. Inhibition of cell proliferation by hydroxyurea caused an increase in hyaluronic acid synthesis. The effect of IL-1β on hyaluronic acid synthesis in the presence of hydroxyurea was increased over untreated and IL-lβ-treated controls, but equivalent to the hydroxyurea-treated controls. Thus the effect of IL-1β on hyaluronic acid synthesis may be independent of cell proliferation. Furthermore, inhibition of prostaglandin E2 synthesis by indomethacin abolished the effect of IL-1β on hyaluronic acid synthesis. Inhibition of new protein synthesis by cycloheximide negated the effect of IL-β on hyaluronic acid synthesis. This may be related to inhibition of new hyaluronate synthetase synthesis, since IL-1β stimulated the level of hyaluronate synthetase activity. Sepharose CL-2B chromatography revealed that most of the newly synthesized hyaluronic acid was of large molecular size. The cells exposed to IL-1β retained more large molecular size hyaluronic acid in their cell layer environment than did the control cells. These responses by fibroblasts to IL-1β may be indicative of early tissue repair.     

Effect of phenytoin on interleukin-1β production in human gingival fibroblasts challenged to tumor necrosis factor αin vitro

Effects and interaction of tumor necrosis factor α (TNFα) and the antiepileptic drug phenytoin (PHT) on interleukin-1β (IL-1β) production as well as on prostaglandin E₂ (PGE₂) formation were studied in gingival fibroblasts in vitro. TNFα, in contrast to PHT, dose-dependently stimulated the production of cell-associated IL-1β. The stimulatory effect of TNFα on IL-1β production was accompanied by enhanced PGE₂ formation. When PHT and TNFα were added simultaneously, the drug potentiated the stimulatory effect of TNFα on both IL-Iβ production and PGE₂ formation. The major PHT metabolite, p-HPPH, did not affect IL-1β production, either alone or in combination with TNFα. The production of IL-1β induced by TNFα and the combination of TNFα and PHT was further enhanced in the presence of the prostaglandin endoperoxide (PGH) synthase inhibitors, indomethacin and flurbiprofen. The PHT-mediated enhancement of TNFα-induced IL-1β production and PGE₂ formation in gingival fibroblasts may be an important link in the pathogenesis of gingival overgrowth induced by PHT.     

lnterleukin-1β and phenytoin reduce α1 (1) procollagen mRNA expression in human gingival fibroblasts

Effects of and interactions between interleukin-1β (IL-1 β) and phenytoin (PHT) on α1 (I) procollagen gene and protein expression in human gingival fibroblasts and its relation to prostaglandin E₂ (PGE₂) formation were studied. IL-1β (300 pg/ ml) reduced the steady-state level of αl(I) procollagen mRNA by 50% and decreased the amount of procollagen I by 35%. PHT (10 μg/ml) reduced the level of α1(I) procollagen mRNA by 40% but the amount of procollagen I in the medium was unchanged. In combination with IL-1β, PHT potentiated the inhibitory effect of IL-1β on αl(I) procollagen mRNA level that was accompanied by an increased PGE₂ formation. Preincubation with indomethacin (10^-6m) partially reduced the inhibitory effect of IL-1β as well as of IL-1β in combination with PHT on the mRNA level of αl(I) procollagen. The inhibitory effect of PHT was unaffected by indomethacin treatment. Addition of exogenous PGE₂ (≥10 nm) dose-dependently reduced steady-state level of α1(I) procollagen mRNA as well as the amount of procollagen 1. The study indicates that IL-1 reduces the expression of αl(I) procollagen mRNA in human gingival fibroblasts partly by a prostaglandin endoperoxide (PGH) synthase-mediated pathway and partly by a PGH-synthase independent pathway, whereas PHT reduces α1(I) procollagen gene expression by a PGH-synthase independent pathway. The potentiation of the inhibitory effect of IL-1 induced by PHT was mediated mainly by a PGH-synthase dependent pathway.     

Effects of cytokines on gingival fibroblasts in vitro are modulated by the extracellular matrix

Fibroblast function in gingival tissue is thought to be regulated by the local cellular environment – both the extracellular matrix and soluble factors. In an attempt to artificially re-create this situation fibroblasts have been cultured within 3-dimensional collagen gels in an environment more physiologically comparable to connective tissue. Using such a model we investigated the effects of the extracellular matrix on gingival fibroblast growth and synthetic activity and on the cellular responsiveness to 4 soluble factors – epidermal growth factor (EGF), platelet-derived growth factor (PDGF), transforming growth factor-beta (TGF- β ₁) and interleukin-1 β (IL-1 β ). Fibroblasts cultured within collagen gels showed similar growth rates, an increased production of collagen but reduced levels of hyaluronan synthesis in comparison to cells in monolayer culture. Cellular responsiveness to soluble mediators was also modulated by the collagen matrix, with a generalised reduction in response by cells embedded within the matrix. The stimulatory effects of EGF and PDGF on cell growth in monolayer over a 14-day period were only found during the initial stages of culture within gels. Similarly the stimulation of matrix production by cells induced by TGF- β ₁, on plastic was reduced or even negated when cells were cultured in collagen gels. On plastic IL-1 β significantly stimulated cell growth but had no effect on either collagen or hyaluronan production by fibroblasts. In gel cultures, this cytokine had no effect on cell proliferation, but significantly inhibited both collagen and hyaluronan synthesis. These findings further illustrate the usefulness of fibroblast-populated collagen gels as a model system for studying the modulatory effects of soluble factors and extracellular matrix molecules on fibroblast function in vitro .     

Synergistic enhancement of collagenous protein synthesis by human gingival fibroblasts exposed to nifedipine and interleukin-1-beta in vitro

Abstract: Gingival overgrowth commonly occurs coincident to therapy with calcium channel blockers. The biologic mechanism for this condition is unknown; however, many clinicians suggest that poor oral hygiene may contribute to development of the overgrowth. This study tests the hypothesis that collagenous protein synthesis by gingival fibroblasts is synergistically enhanced when they are exposed to both nifedipine (N) and the pro-inflammatory cytokine, interleukin-1-beta, a cytokine expressed in inflamed gingiva. Human gingival fibroblasts were isolated from biopsies of normal gingiva and cells separated into two groups. Group 1 was exposed to media containing 0, 5, 50, or 500 pg/ml IL-1-beta, or 10⁻⁷ M N for 7 days; Group 2 was exposed to those concentrations of IL-1-beta +10⁻⁷ M N. [³H]-proline was added to the medium for the final 24 h. Cells and matrix were harvested and radioactivity determined by liquid scintillation analysis. Means (d.p.m./10³ cells) were compared by factorial ANOVA and Scheffè comparisons. Collagenous protein synthesis was significantly reduced by 5 pg/ml IL-1-beta +10⁻⁷ M N and enhanced by 500 pg/ml IL-1-beta +10⁻⁷ M N as compared to N or IL-1-beta alone. Thus, patients may be more susceptible to gingival overgrowth coincident to nifedipine therapy as a result of the synergistic enhancement of connective tissue synthesis by these agents.     

Prostaglandin E2 and I2 regulate intercellular adhesion molecule-1 expression in interleukin-1 beta-stimulated human gingival fibroblasts

The present study investigated the effect of prostaglandin (PG) E₂ and PGI₂ on intercellular adhesion molecule-1 (ICAM-1) expression in interleukin-1β (IL-1β)-stimulated human gingival fibroblasts (HGF). IL-1β potently induced ICAM-1 expression in HGF and indomethacin, a cyclooxygenase inhibitor, enhanced ICAM-1 expression in the cells. These data showed that endogenous PGs generated by HGF stimulated with IL-1β downregulated ICAM-1 expression. IL-1β significantly increased the levels of PGE₂ and, to a lesser extent, those of 6-keto-PGF_1α (a stable metabolite of PGI₂) in the culture media of HGF. Indomethacin completely inhibited the production of PGE₂ and 6-keto-PGF_1α in IL-1β-stimulated HGF. Exogenous PGE₂ and carbacyclin (a stable derivative of PGI₂) in the presence of indomethacin dose-dependently suppressed ICAM-1 expression in IL-1β-challenged HGF. Since PGE₂ and PGI₂ are known to elevate intracellular cyclic AMP (cAMP) levels, we examined the effect of dibutyryl cAMP, a cAMP analogue, and isobutylmethylxanthine, a phosphodiesterase inhibitor, on ICAM-1 expression. Both agents downregulated ICAM-1 expression in IL-1β-stimulated HGF. These results suggest that PGE₂ and PGI₂ downregulate ICAM-1 expression in IL-1β-stimulated HGF through a cAMP-dependent mechanism and that intracellular cAMP elevation in HGF may control inflammatory and immune responses in periodontal disease.     

Benzydamine reduces prostaglandin production in human gingival fibroblasts challenged with interleukin-1 beta or tumor necrosis factor alpha

Benzydamine [1-benzyl-3-(3-dimethylamino)propoxy-1H-indazole] is a drug with analgesic, anesthetic, antimicrobial and anti-inflammatory activity. The purpose of the present study was to investigate the effect of benzydamine on prostaglandin production in human gingival fibroblasts. Benzydamine significantly reduced the basal production of both prostaglandin E2 (PGE2) and 6-keto-PGF1 alpha, the stable breakdown product of prostaglandin I2 (PGI2), in unstimulated human gingival fibroblasts. When the cells were treated simultaneously with benzydamine and the cytokines IL-1 beta or TNF alpha, the agent benzydamine reduced (P < 0.05) the stimulatory effect of IL-1 beta and TNF alpha respectively, on PGE2 and PGI2 production in human gingival fibroblasts. Furthermore, benzydamine reduced (P < 0.05) both the basal level and the cytokine-induced 3H-arachidonic acid release 3H-(AA) in gingival fibroblasts. The addition of exogenous arachidonic acid to the cells resulted in enhanced PGE2 production, which was reduced (P < 0.05) in the presence of benzydamine. The study indicates that benzydamine reduces the prostaglandin synthesis in gingival fibroblasts, partly at the level of phospholipase A2, by diminishing the liberation of arachidonic acid (AA) from phospholipids, and partly at the level of cyclooxygenase. The inhibitory effect of benzydamine on prostaglandin production may explain the anti-inflammatory effect of the drug in the management of patients with oral inflammatory conditions.     

Regulation of human gingival fibroblast growth and synthetic activity by cyclosporine-A in vitro

Gingival overgrowth is an adverse side-effect seen in a proportion of patients taking cyclosporin-A which indicates that cyclosporine-A may modulate the activities of cells other than T lymphocytes. Therefore, the effect of cyclosporine on human gingival fibroblasts has been studied in vitro. Cyclosporine-A was found to stimulate DNA synthesis and the proliferative activity of these cells with maximal stimulation noted at a concentration of 10(-9) g/ml. Although this stimulation was most noticeable in the presence of 10% fetal calf serum, proliferation still occurred in serum-free medium. In the presence of lipopolysaccharide, at a concentration which normally inhibits gingival fibroblast proliferation, cyclosporine retained its capacity to stimulate proliferative activity. Fibroblasts isolated from overgrown gingival tissue responded to a greater extent than those isolated from a healthy site from the same individual. This stimulatory effect was not restricted to gingival fibroblasts, since human foreskin fibroblasts responded in a similar fashion. Cyclosporine-A did not significantly alter protein or proteoglycan production by these cells. These responses are considered to reflect the in vivo response of gingival overgrowth in patients taking cyclosporine-A. The reversal of lipopolysaccharide inhibition of gingival fibroblast proliferation by cyclosporine-A may explain, in part, why gingival overgrowth is most prominent in areas of heavy dental plaque accumulation.     

Prostaglandin E2 secretion from gingival fibroblasts treated with interleukin-1β: effects of lipid extracts from Porphyromonas gingivalis or calculus

Complex lipids of Porphyromonas gingivalis have been identified in lipid extracts from calculus-contaminated root surfaces and in diseased gingival tissues. However, little is known about the biological effects of these complex lipids on host cells. The purpose of this study was to evaluate the effects of P. gingivalis or calculus lipids on prostaglandin secretion from gingival fibroblasts. Lipids were extracted from paired subgingival plaque and teeth samples, and calculus-contaminated root surfaces before and after scaling and root planing, in order to determine the relevant levels of lipid extracts for the treatment of gingival fibroblasts in culture. Primary cultures of gingival fibroblasts were exposed to lipid extracts from either P. gingivalis or calculus/teeth for a period of 7 days. Control and lipid-treated cultures were exposed to human recombinant interleukin-1β for 48 h and prostaglandin secretion from interleukin-1β-treated fibroblasts was compared with control and lipid-treated fibroblasts without interleukin-1β treatment. These experiments demonstrated that P. gingivalis lipids or calculus-tooth lipids potentiate interleukin-1β-mediated prostaglandin secretory responses from gingival fibroblasts. Additionally, P. gingivalis or calculus-tooth lipid extracts were readily taken up by gingival fibroblasts as measured by bacterial fatty acid recovery in lipid extracts of cultured fibroblasts. These results indicate that bacterial lipid penetration into gingival tissues in combination with a chronic inflammatory response may substantially potentiate prostaglandin secretion from gingival fibroblasts, thereby promoting tissue destructive processes associated with adult periodontitis.     

The bone resorbing activity released by gingival fibroblasts isolated from patients with periodontitis is independent of interleukin-1

Supernatants from gingival fibroblast cultures obtained from 14 patients with periodontal disease contained factor(s) capable of stimulating bone resorption in vitro, as assessed by the release of 45Ca from neonatal mouse calvariae. The possibility that the factor(s) was interleukin-1 alpha (IL-1 alpha), IL-1 beta or prostaglandin E2 (PGE2) was next investigated. The human fibroblast conditioned media (HFCM) stimulated PGE2 biosynthesis in bone. The stimulatory effect by HFCM on 45Ca release, however, was not affected by blocking prostaglandin biosynthesis with indomethacin. In contrast, 45Ca release induced by IL-1 alpha, IL-1 beta, thrombin and bradykinin was significantly reduced by indomethacin, whereas the effects of PTH and PTHrP were unaffected by indomethacin. The concentration of PGE2 in HFCM was too low to be solely responsible for the 45Ca release response. In addition, the amount of bone resorbing activity produced by the gingival fibroblasts was unaffected by cyclo-oxygenase inhibitors. Similar to IL-1 alpha and IL-1 beta, the stimulatory effect of HFCM was inhibited by gamma-interferon. HFCM did not stimulate cyclic AMP formation in the mouse calvarial bones. Antisera which specifically blocked human IL-1 alpha or IL-1 beta induced 45Ca release, and the specific IL-1 receptor antagonistic protein, did not inhibit the stimulatory effect of HFCM. These data show that gingival fibroblasts secrete bone resorbing factor(s) which is not due to IL-1 and which stimulates bone resorption by a prostaglandin- and cyclic AMP-independent mechanism.     

Interleukin 1, interleukin 6 and transforming growth factor-β production by human gingival mononuclear cells following stimulation with Porphyromonas gingivalis and Fusobacterium nucleatum

Gingival mononuclear cell production of interleukin 1 (IL-1), interleukin 6 (IL-6) and transforming growth factor-β(TGF-β) after stimulation with the putative periodontopathic bacteria, Porphyromonas gingivalis and Fusobacterium nucleatum was investigated. Using an ELISA method, gingival mononuclear cells extracted from 18 adult periodontitis subjects were found to be producing IL-1. However, IL-1 activity could only be detected in 5 out of these 18 cases when tested using a thymocyte proliferation bio-assay, suggesting the presence of IL-1 inhibitors. Depletion of monocytes from peripheral blood cultures resulted in a significant decrease in IL-1 activity following P. gingivalis stimulation while there was no effect in the level of IL-1 activity following stimulation with F. nucleatum. This suggests that P. gingivalis and F. nucleatum stimulate different cell types to produce IL-1. Like IL-1. IL-6 production by gingival mononuclear cells was significantly greater than that produced by the control peripheral blood mononuclear cells. Following P. gingivalis and F. nucleatum stimulation, higher levels of IL-6 could be detected; however, both organisms stimulated similar levels. Intracytoplasmic immunofluorescence staining demonstrated a lower percent TGF-β⁺ cells in bacterial stimulated peripheral blood mononuclear cell cultures compared with cells in medium alone. In the gingival mononuclear cell cultures, the percentage TGF-β⁺ cells peaked at day 1 in F. nucleatum -stimulated, whereas in P. gingivalis -stimulated cultures the peak TGF-β⁺ cells occurred at day 3, again suggesting stimulation of different cell subsets. These results ilustrate that different periodontopathic bacteria may stimulate different cell types to produce cytokines which may have synergistic or antagonistic effects.     

Interleukin-1α produced in human gingival fibroblasts induces several activities related to the progression of periodontitis by direct contact

Previous observations suggest that interleukin-1 (IL-1) may play an important role in the progression of periodontitis. In the present study, we investigated whether a cell-associated IL-1α (CAIL-lα) produced in human gingival fibroblasts (HGF) induces biological activities related to the progression of periodontitis. HGF were treated with recombinant human IL-1β (rhIL-1β) for 12 h. After that, the cell layers of HGF were washed 3 times with fresh medium and were then fixed with 1% paraformaldehyde. The fixed cell layers of HGF were used for assays for bone resorbing activity, prostaglandin E₂ (PGE₂) production and collagenase activity. Fixed cell layers of HGF treated with rhIL-1β enhanced not only calcium release from BALB/c mouse calvaria but also PGE₂ production and collagenase activity in HGF and human periodontal ligament fibroblasts (HPLF) cultured on the fixed cell layers. These activities were neutralized by treatment with monoclonal mouse anti-human IL-1α antibody, but monoclonal mouse antihuman IL-1β antibody showed no effects on these activities. The induction of these activities by fixed cell layers of HGF required direct contact between the fixed cell layers and the calvaria, HGF, or HPLF. These results suggest that CAIL-1α produced in HGF treated with rhIL-1β induces bone resorbing activity, PGE₂ production and collagenase activity in the target cells by direct contact; CAIL-lα may play an important role in the progression of periodontitis.     

Production of inflammatory mediators and cytokines by human gingival fibroblasts following bacterial challenge

Bacteria can indirectly affect the course of periodontal diseases by activating host cells to produce and release inflammatory mediators and cytokines. These mediators and cytokines, manifest potent proinflammatory and catabolic activity and may play key roles in local amplification of the immune response as well as in periodontal tissue breakdown. This study tested the effect of Actinobacillus actinomycetemecomitans (Aa) and Campylobacter rectus (Cr) challenge on PGE₂, IL-1β, IL-6 and IL-8 production by human gingival fibroblasts (HGF). Contact-inhibited HGF were prepared and formalin-killed bacterial cells ( Aa JP2, ATCC 29523 & 33384 and Cr ATCC 33238) at 10⁶-10⁹ were added to the HGF. Culture supernatants were collected at varying time intervals and analyzed for cytokine and mediator content. All concentrations of Aa JP2 and Cr ATCC 33238 suppressed IL-1β production up to approximately 50% during the initial 3-12-h period. No bacterial concentration tested was able to increase IL-1β production above the maximum basal levels. Both bacterial species stimulated production of IL-6 and IL-8. Aa JP2 did not affect PGE₂ levels significantly, whereas Cr ATCC 33238 was stimulatory only at the highest concentration tested (10⁹). There were no significant differences among the three Aa strains with respect to IL-1β production. However, Aa ATCC 29523 and ATCC 33384 were less capable of stimulating IL-6 secretion and more efficient in stimulating. IL-8 production than Aa JP2. In general. Cr was the most potent enhancer of cyto-kine and mediator production by HGF. In conclusion, Aa and Cr are capable of amplifying the local immune response and promoting periodontal tissue inflammation by stimulating HGF to secrete mainly IL-6 and IL-8.     

Enhanced synthesis of hyaluronic acid by human gingival fibroblasts exposed to human dental bacterial extract

Hyaluronic acid synthesis was studied in human gingival fibroblast cultures exposed to human dental bacterial plaque extract. The cells were stimulated to produce large amounts of hyaluronic acid (HA) into the culture medium. The extract did not have any direct effect on the activity of hyaluronic acid synthetase enzyme complex, indicating that the increased hyaluronic acid synthesis was caused by metabolic alterations in gingival cells. Dental plaque extract also decreased the molecular weight of hyaluronic acid. This was obviously caused by the plaque derived hyaluronidase, because denaturation of plaque proteins by heating prevented this degradation. On the other hand, the stimulatory effect on the HA synthesis by the plaque extract was not destroyed by heating. The increased production of low molecular weight HA by gingival fibroblasts after plaque exposure is suggested to have a role in the pathogenesis of chronic periodontal disease in vivo .     

Bradykinin-2 receptor-mediated release of 3H-arachidonic acid and formation of prostaglandin E2 in human gingival fibroblasts

Bradykinin stimulated production of prostaglandin E2 (PGE2) and the release of 3H-arachidonic acid by gingival fibroblasts in a time- and dose-dependent manner. The effect on PGE2 biosynthesis was seen already after 15 seconds and was maximal after 5 minutes. Several structurally unrelated inhibitors of arachidonic acid metabolism via the cyclooxygenase pathway totally abolished the PGE2 response to bradykinin. The stimulation of PGE2 formation was seen at and above 10 nmol/l of bradykinin. Des-Arg9-bradykinin was 100-fold less potent compared to bradykinin. Des-Arg9-Leu8-bradykinin did not antagonize bradykinin-induced PGE2 formation. Met-Lys-bradykinin and Lys-bradykinin also enhanced PGE2 formation in gingival fibroblasts. The stimulatory action of bradykinin on 3H-arachidonic acid release was observed after 30 s and progressively increased for at least 15 min. The stimulatory effect on 3H-arachidonic acid release by bradykinin was seen at and above 10 nmol/l, whereas des-Arg9-bradykinin was without effect up to a concentration of 1 mumol/l. Indomethacin did not affect bradykinin-induced 3H-arachidonic acid release. These data show that bradykinin, via a B2-receptor-mediated pathway, can stimulate arachidonic acid release and subsequent prostanoid formation in gingival fibroblasts. Consequently, gingival fibroblasts may contribute, by a bradykinin-regulated reaction, to the enhanced amounts of prostanoids found in gingival tissues and crevicular fluids in patients with periodontal diseases.     

Triclosan reduces prostaglandin biosynthesis in human gingival fibroblasts challenged with interleukin-1 in vitro

Abstract The effect of the toothpaste ingredient triclosan (2,4,4′-trichloro-2′-hydroxyldiphenyl ether) on the prostaglandins biosynthesis in human gingival fibroblasts challenged with interleukin-1β (IL-1β) or tumor necrosis factor α (TNFα) was studied in vitro. When gingival fibroblasts were treated simultaneously with triciosan and IL-1β, the stimulatory effect of IL-1β on prostaglandin E₂ (PGE₂) and PGI₂ formation was reduced in a dose-dependent manner by triclosan. Triclosan also reduced the PGE: formation induced by TNFα. Furthermore, the capacity of IL-1β to induce release of [³H] arachidonic acid from prelabelled gingival fibroblasts was reduced in the presence of triclosan. Addition of exogenous unlabelled arachidonic acid (AA) to the cells resulted in enhanced PGE₂ formation which was reduced by triclosan. The upregulation of the metabolism of AA to PGE₂ induced by IL-lβ, was markedly reduced in the presence of triclosan. The study indicates that the stimulatory effect of IL-1β on prostanoid formation (PGE₂, PGI₂) in human gingival fibroblasts was diminished in the presence of triciosan partly at the level of phospholipase A₂ and partly at the level of cyclooxygenase. The present data that triclosan. in vitro, inhibits the production of inflammatory mediators such as prostaglandins suggests that this can be an aspect of its clinical effect on gingivitis, in addition to its antibacterial effect.     

TGF-β1 influences early gingival wound healing in rats: an immunohistochemical evaluation of stromal remodelling by extracellular matrix molecules and PCNA

The effect of topically applied transforming growth factor β1 (TGF - β1) on the rat gingival wound healing process after flap surgery was evaluated by immunohistochemistry for extracellular matrix molecules (ECM), such as tenascin, heparan sulfate proteoglycan (HSPG) and type IV collagen, and for proliferating cell nuclear antigen (PCNA) in fibroblasts. TGF-β1 solution was applied to the surgical wound experimental sites. Two μg/μl were applied at the time of the operation, and 1 μg/μl at days 1 and 2 after surgery, with contralateral control sites receiving the vehicle alone. Periodontal tissues were histologically examined at 3 and 7 days post-surgery. Tenascin was found to be more strongly stained in the granulation tissue from experimental sites at 3 days post-surgery. At 7 days post-surgery, HSPG-positive areas in granulation tissue had become smaller and there was a prominent proliferation of PCNA-positive fibroblast-like cells and type IV collagen-positive blood vessels. These results suggest that TGF-β1 applied to surgical wounds influences early proliferation of gingival fibroblast-like cells, the formation of blood vessels, and ECM remodelling. In conclusion, TGF-β1 application appears to promote granulation tissue formation in periodontal wound healing.     

Interleukin-1β+3953 allele 2: association with disease status in adult periodontitis

Abstract. Adult periodontitis is a complex multifactorial disease whose etiology is not well defined. The pro-inflammatory and bone resorptive properties of interleukin-1 beta (IL-1β) strongly suggest a role for this cytokine in the pathogenesis of periodontal disease. In the study reported here, the frequency of IL-1β⁺³⁹⁵³ genotypes including allele 2 of the IL-1β⁺³⁹⁵³ restriction fragment length bi-allelic polymorphism was significantly increased in patients with advanced adult periodontitis compared to those with early and moderate disease. Furthermore, allele 2 was associated with increased production of IL-1β by activated peripheral blood polymorphonuclear cells of patients with advanced disease, although this increase failed to reach statistical significance. Finally, the data obtained revealed significant linkage disequilibrium between allele 2 of the IL-1β⁺³⁹⁵³ polymorphism and allele 2 of the bi-allelic IL-1α⁻⁸⁸⁹ polymorphism in both patients and orally healthy controls. These findings provide new insight into the possible role of IL-1α and β gene polymorphisms in the susceptibility to adult periodontitis.     

Inhibition of human oral squamous carcinoma cell (SCC-25) proliferation by prostaglandin E2 and vitamin E succinate

The primary objective of this investigation was to study the effect of D-alpha-tocopherol acid succinate (vitamin E succinate) and prostaglandin E₂ (PGE₂), individually and in combination, on the proliferation of human tongue squamous carcinoma cells (SCC-25) in vitro. Test compounds in varying concentrations were incubated with cells in serum-free Dulbecco's Modified Eagle's Medium-Ham's F-12 Medium (50:50), supplemented with 0.1% albumin for sixteen hours. Cell proliferation was measured by the incorporation of [3H] thymidine in acid-insoluble material (i.e. DNA). Prostaglandin E₂ and vitamin E succinate, individually at 10⁻⁹ 10⁻⁶ M, caused significant dose-dependent inhibition in DNA synthesis. A combined dose of each compound at 10⁻⁵ M resulted in significant additive inhibition which averaged 43.53% (p < 0.005). Addition of indomethacin (INDO) to cell cultures induced significant dose-dependent stimulation in DNA synthesis. Hence, we might suggest that the overall potential of vitamin E in controlling malignant cell proliferation in vivo could be due to its own effect combined with that of endogenous PGs which are normally produced in excessive amounts by malignant cells.