Chemokine expression in human oral keratinocyte cell lines and keratinized mucosa

Potential effects of samsum ant, Brachyponera sennaarensis, venom on TNF-α/NF-κB mediated inflammation in CCL4-toxicity in vivo

Background

Ant venom shows antimicrobial, anti-parasitic and anti-inflammatory activities, both in vitro and in vivo. Our recent studies have confirmed the role of samsum ant venom (SAV) as a powerful antioxidant. This study aimed to investigate whether SAV as a potential treatment for CCl4-induced acute liver toxicity in an animal (rat) model.

Methods

Thirty-two rats were assigned into four groups; the first one served as the control. The second group received a single dose of 1 ml/kg CCl₄ in a 1:1 ratio with olive oil through an intraperitoneal injection. The third group received a single dose of 1 ml/kg CCl₄ and then treated with SAV at a dose of 100 μg SAV twice a week for three weeks. The fourth group received a dose of 100 μg SAV only twice a week for three weeks. ELISA, RT-PCR and histopathological examinations were applied.

Results

Results showed that antioxidant enzymes were significantly reduced in the diseased animals. SAV was found to significantly restore the oxidative stability in diseased animals. ELISA estimation and RT-PCR analysis also showed significant upregulation of both nuclear factor (κB) NF-κB and inhibitor (κB) IκB, respectively, in the diseased animals compared to the normal ones. The expression of tumour necrosis factor alpha (TNF-α) and pro-apoptotic receptor (Fas) were also significantly up-regulated in the diseased rats. Interestingly, SAV was found to significantly restore NF-κB, IκB and TNF-α in the diseased rats to the normal values. As a result, liver enzymes, serum proteins and lipid concentrations were significantly improved by SAV in CCl4-animals in comparison with the control ones. Moreover, SAV obviously improved the hepatic tissues of the same group was.

Conclusion

SAV treatment restores the normal biochemical and oxidative stability by improving the TNF-α/NF-κB mediated inflammation in CCL4-treated rats.

Camel milk peptide improves wound healing in diabetic rats by orchestrating the redox status and immune response

BACKGROUND

Diabetes mellitus alters oxidative stability and immune response. Here, we investigated the impact of a peptide extracted from camel milk (CMP) on the oxidative status, transcription factor kappa-B (NF-kB) and inflammatory cytokine in diabetic wounds.

METHODS

Rats were assigned into three groups: control, diabetic induced (DM) and diabetic induced with multiple doses of CMP for a week (DM-CMP).

RESULTS

DM showed a sharp decline in the activity of major antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT) and glutathione (GSH) compared to the control. The DM-CMP group, however, showed a noticeable replenishment in the activity of these enzymes compared to the DM group. The CMP-treated group also showed a normal level of lipid peroxidation marker (MDA) compared to the DM rats. Furthermore, ELISA analysis of serum TNF-α protein showed an elevated level in diabetic rats in comparison to control serum. However, RT-PCR analysis of locally wounded skin tissues revealed that diabetes down-regulates the RNA expression of both TNF-α and MIF genes in comparison to the control samples but that CMP was found to restore RNA expression significantly. Although it was elevated in CMP-treated rats after one day of wound incision, the NF-kB protein level was significantly decreased seven days after the incision in comparison to the animals in the diabetic group.

CONCLUSION

CMP, therefore, can be seen an effective antioxidant and immune stimulant that induces oxidative stability and speeds up wound healing in diabetic model animals, making it a potential adjuvant in improving wound healing in those with diabetic conditions.

Evaluation of the effect of nicotine and metabolites on the periodontal status and the mRNA expression of interleukin-1β in smokers with chronic periodontitis

Background and Objective:

Smoking is an important environmental risk factor involved in the causation and progression of periodontal disease. Smoking can impair various components of the host immune response and immune system. The virulence factors of periodontal pathogens stimulate inflammatory cytokine expression by mononuclear cells. IL-1β is the key mediator involved in the pathogenesis and disease progression. Therefore, whole gingival biopsy samples are assessed for this increased expression of IL-1.

Materials and Methods:

29 male subjects’ age and gender matched were divided into three groups based on the periodontal and smoking status (Group A:healthy, Group B: non-smokers suffering from chronic periodontitis, Group C: smokers suffering from chronic periodontitis). Periodontal parameters like plaque index, gingival index, probing pocket depth and clinical attachment level were recorded at baseline and post scaling. The mRNA expression of IL-1β was determined by real time polymerase chain reaction and correlated with the periodontal and smoking status.

Results:

The improvement in the periodontal parameters was statistically significant in the non- smokers (Group B) and there was a 2 fold increase in the mRNA expression in this group. The smokers (Group C) showed lesser improvement in the periodontal parameters and there was an 8 fold increase in the mRNA expression of IL-1β.

Conclusion:

Association of smoking status with periodontal destruction can thus be correlated with the increased mRNA expression of IL-1β in chronic periodontitis patients.

The chemokine receptors CXCR1 and CXCR2 regulate oral cancer cell behaviour

BACKGROUND

Chemokines regulate physiological and pathological leucocyte trafficking, and chemokine receptors play a role in tumorigenesis. Expression of interleukin-8 (IL-8) receptors CXCR1 and CXCR2 has been shown in oral squamous cell carcinoma (OSCC) but remains poorly characterised. This aim of this study was to investigate CXCR1 and CXCR2 expression on normal oral keratinocytes (NOKs) and oral cancer cell lines (OCCL) and their relative response when exposed to IL-8 and growth-related oncogene-α (which selectively binds CXCR2).

METHODS

mRNA and protein expression was studied using RT-PCR, immunocytochemistry and flow cytometry. ELISAs were used to investigate ERK1/2 phosphorylation and MMP production, whereas a MTS-based assay was employed to study proliferation. Migration assays were carried out using modified Boyden chambers with a matrigel coating used for invasion assays.

RESULTS

mRNA expression of CXCR1 and CXCR2 was seen in both NOKs and OCCL with significantly higher protein expression in OCCL. Exposure to IL-8 and GROα increased intracellular ERK phosphorylation, proliferation, migration and invasion with OCCL showing a greater response than NOKs. These effects were mediated through CXCR1 and CXCR2 (for IL-8) and CXCR2 (for GROα) as receptor-blocking antibodies significantly inhibited the responses. IL-8 and GROα also increased MMP-9 release from NOKs and OCCL with significantly higher amounts released by OCCL. However, an increase in MMP-7 production was only seen in OCCL.

CONCLUSIONS

Functional CXCR1 and CXCR2 exist on normal and cancerous oral epithelial cells, and our data suggests a role for these receptors in oral cancer biology.

Whey protein enhances normal inflammatory responses during cutaneous wound healing in diabetic rats

Background

Prolonged wound healing is a complication of diabetes that contributes to mortality. Impaired wound healing occurs as a consequence of excessive reactive oxygen species (ROS) production. Whey protein (WP) is able to reduce the oxygen radicals and increase the levels of the antioxidant glutathione. Thus, the aim of this study was to determine whether dietary supplementation with WP could enhance normal inflammatory responses during wound healing in diabetic rats. Animals were assigned into a wounded control group (WN), a wounded diabetic group (WD) and a wounded diabetic group orally supplemented with whey protein (WDWP) at a dose of 100 mg/kg body weight.

Results

Whey protein was found to significantly decrease the levels of malondialdehyde (MDA), nitric oxide (NO) and ROS. A significant restoration of the glutathione level was observed in WDWP rats. During the early wound healing stage, IL-1β, TNF-α, IL-6, IL-4 and neutrophil infiltration were significantly decreased in WD mice. WP supplementation was found to restore the levels of these inflammatory markers to the levels observed in control animals. In addition, the time required for wound healing was significantly prolonged in diabetic rats. WP was found to significantly decrease the time required for wound healing in WDWP rats.

Conclusion

In conclusion, dietary supplementation with WP enhances the normal inflammatory responses during wound healing in diabetic mice by restoring the levels of oxidative stress and inflammatory cytokines.

Immunohistochemical comparison of indermil with traditional suture materials in dental surgery

The aim of this experimental study was to evaluate the effects of indermil on the closure of oral mucosa wounds in comparison with conventional sutures by investigating interleukin 1β (IL-1β) and tumor necrosis factor α (TNF-α) markers immunohistochemically in an animal model.The animals were anesthetized by intraperitoneal injection of ketamine (90 mg/kg body weight). Straight incisions were made to the buccal mucosa of the animals. Animals were randomly assigned to 5 groups. Five different materials were used in the study. These were silk, plain catgut, monocryl, vicryl rapide (polyglactin 910), and indermil (N-butyl-2-cyanoacrylate). The wounds were closed primarily. After the region of wounds was examined clinically at the 2nd, 7th, 14th, and 21st days, excisional biopsies were performed, and the tissue samples were examined histopathologically and immunohistochemically.On the 14th day, TNF-α and IL-1β levels were high in the plain catgut group, moderate in the indermil group, and mild in the monocryl, silk, and vicryl rapide groups. On the 21st day, TNF-α and IL-1β levels were moderate in the plain catgut group, mild in the indermil and monocryl groups, and nonsignificant in the silk group. After the second day, TNF-α and IL-1β levels were mild in the monocryl, silk, and vicryl rapide groups.Plain catgut had more negative effects than indermil on wound healing. Indermil should be applied to oral mucosa wounds together with sutures to provide better tissue support.

Response of mouse skin to tattooing: use of SKH-1 mice as a surrogate model for human tattooing

Tattooing is a popular cosmetic practice involving more than 45 million US citizens. Since the toxicology of tattoo inks and pigments used to formulate tattoo inks has not been reported, we studied the immunological impact of tattooing and determined recovery time from this trauma. SKH-1 hairless mice were tattooed using commercial tattoo inks or suspensions of titanium dioxide, cadmium sulfide, or iron oxide, and sacrificed at 0.5, 1, 3, 4, 7, or 14 days post-tattooing. Histological evaluation revealed dermal hemorrhage at 0.5 and 1 day. Acute inflammation and epidermal necrosis were initiated at 0.5 day decreasing in incidence by day 14. Dermal necrosis and epidermal hyperplasia were prominent by day 3, reducing in severity by day 14. Chronic active inflammation persisted in all tattooed mice from day 3 to 14 post-tattooing. Inguinal and axillary lymph nodes were pigmented, the inguinal being most reactive as evidenced by lymphoid hyperplasia and polymorphonuclear infiltration. Cutaneous nuclear protein concentrations of nuclear factor-kappa B were elevated between 0.5 and 4 days. Inflammatory and proliferative biomarkers, cyclooxygenase-1, cyclooxygenase-2, and ornithine decarboxylase protein levels were elevated between 0.5 and 4 days in the skin and decreased to control levels by day 14. Interleukin-1 beta and interleukin-10 were elevated in the lymph nodes but suppressed in the tattooed skin, with maximal suppression occurring between days 0.5 and 4. These data demonstrate that mice substantially recover from the tattooing insult by 14 days, leaving behind pigment in the dermis and the regional lymph nodes. The response seen in mice is similar to acute injury seen in humans, suggesting that the murine model might be a suitable surrogate for investigating the toxicological and phototoxicological properties of ingredients used in tattooing.

Dietary supplementation of N-acetylcysteine enhances early inflammatory responses during cutaneous wound healing in protein malnourished mice

Prolonged wound healing is a complication that contributes to the morbidity and mortality of protein malnutrition (PM). The molecular mechanisms that underlie impaired wound healing in PM may begin in the early inflammatory stage of the process. We hypothesized that the impaired wound healing observed in PM occurs as a consequence of excessive reactive oxygen species (ROS) production that impairs the wound healing process by depressing nuclear factor kappa B (NFkappaB) activation and the subsequent synthesis and release of proinflammatory cytokines that are critical mediators of the inflammatory response. In this study, we showed that the time to wound closure was significantly prolonged in PM mice. During the early wound healing in PM, inhibitory kappa B alpha (IkappaBalpha), interleukin-1beta (IL-1beta) and tumor necrosis factor-alpha (TNF-alpha) expression and neutrophil infiltration were significantly decreased in PM mice. The role of excess ROS in PM was demonstrated by using transgenic mice with overexpression of copper zinc superoxide dismutase and with dietary supplementation of N-acetylcysteine (NAC). Both interventions improved the extent of wound closure in PM mice. Moreover, NAC supplementation in PM mice restored the expression of IkappaBalpha, IL-1beta and TNF-alpha and infiltration of neutrophils to levels observed in control animals. These findings support the notion that wound healing defects in PM may result from dysregulation of ROS-mediated and NFkappaB-regulated signaling pathways.

Bioactive interleukin-1alpha is cytolytically released from Candida albicans-infected oral epithelial cells

Oral epithelial cells are primary targets of Candida albicans in the oropharynx and may regulate the inflammatory host response to this pathogen. This investigation studied the mechanisms underlying interleukin-1alpha (IL-1alpha) release by oral epithelial cells and the role of IL-1alpha in regulating the mucosal inflammatory response to C. albicans. Infected oral epithelial cells released processed IL-1alpha protein in culture supernatants. The IL-1alpha generated was stored intracellularly and was released upon cell lysis. This was further supported by the fact that different C. albicans strains induced variable IL-1alpha release, depending on their cytolytic activity. IL-1alpha from C. albicans-infected oral epithelial cells upregulated proinflammatory cytokine secretion (IL-8 and GM-CSF) in uninfected oral epithelial or stromal cells. Our studies suggest that production of IL-1alpha, IL-8 and GM-CSF may take place in the oral mucosa in response to lytic infection of epithelial cells with C. albicans. This process can act as an early innate immune surveillance system and may contribute to the clinicopathologic signs of infection in the oral mucosa.

Current controversies in oral lichen planus: Report of an international consensus meeting. Part 1. Viral infections and etiopathogenesis

Despite recent advances in understanding the immunopathogenesis of oral lichen planus (LP), the initial triggers of lesion formation and the essential pathogenic pathways are unknown. It is therefore not surprising that the clinical management of oral LP poses considerable difficulties to the dermatologist and the oral physician. A consensus meeting was held in France in March 2003 to discuss the most controversial aspects of oral LP. Part 1 of the meeting report focuses on (1) the relationship between oral LP and viral infection with special emphasis on hepatitis C virus (HCV), and (2) oral LP pathogenesis, in particular the immune mechanisms resulting in lymphocyte infiltration and keratinocyte apoptosis. Part 2 focuses on patient management and therapeutic approaches and includes discussion on malignant transformation of oral LP.

Serum interleukin-8 level is a more sensitive marker than serum interleukin-6 level in monitoring the disease activity of oral lichen planus

BACKGROUND

Oral lichen planus (OLP) is a T-cell-mediated inflammatory disease. Interleukin (IL)-8 is a pro-inflammatory cytokine of host response to injury and inflammation.

OBJECTIVES

To investigate whether serum IL-8 level was a more sensitive marker than serum IL-6 level in monitoring the disease activity of OLP and to assess whether IL-8 was a useful serum marker in evaluating the therapeutic effects of levamisole on OLP patients.

METHODS

In this study, we used a solid phase, two-site sequential chemiluminescent immunometric assay to determine the baseline serum levels of IL-6 and IL-8 in 158 patients with OLP, nine patients with traumatic ulcers (TU) and 54 normal control subjects. Some OLP patients with the serum IL-6 or IL-8 levels higher than the upper limit of normal serum concentration were treated with levamisole for 0.5-6.0 months and their serum IL-6 and IL-8 levels were measured after treatment.

RESULTS

We found that 28% (44 of 158) OLP, 28% (40 of 142) erosive OLP (EOLP), and 25% (four of 16) nonerosive OLP (NEOLP) patients had a serum IL-6 level greater than the upper normal limit of 4.7 pg mL(-1). In contrast, 63% (99 of 158) OLP, 63% (90 of 142) EOLP and 56% (nine of 16) NEOLP patients had a serum IL-8 level greater than the upper normal limit of 8.7 pg mL(-1). In some OLP patients with the serum IL-6 or IL-8 levels higher than the upper limit of normal serum concentration, treatment with levamisole for a period of 0.5-6.0 months could significantly reduce the mean serum IL-6 level from 14.3 +/- 1.9 pg mL(-1) to 3.2 +/- 0.6 pg mL(-1) (P < 0.001) and could significantly reduce the mean serum IL-8 level from 95.8 +/- 17.1 pg mL(-1) to 14.8 +/- 5.8 pg mL(-1) (P < 0.001).

CONCLUSIONS

Because measurement of the serum IL-8 level can detect more OLP patients with an abnormal serum level than measurement of the serum IL-6 level (63% vs. 28%), we conclude that serum IL-8 level is a more sensitive marker than serum IL-6 level in monitoring the disease activity of OLP. Levamisole can modulate both the serum IL-6 and IL-8 levels in OLP patients. IL-8, like IL-6, is also a useful serum marker in evaluating the therapeutic effects of levamisole on OLP patients.

Histopathology of the teeth in segmental odontomaxillary dysplasia: new findings

Histological examination of the deciduous teeth in two cases of segmental odontomaxillary dysplasia (SOMD) showed fibrous enlargement of the pulps, an irregular pulp/dentine interface displaying many pseudoinclusions and pulp stones. There were tubular defects in the coronal dentine from pulp horn to cusp tip, an irregular tubular structure to the circumpulpal dentine of the apical half, a focally deficient odontoblast layer and widespread external resorption. Together with the clinical features of unilateral maxillary enlargement, upper alveolar expansion in the distal segment, increased spacing and delayed eruption of the deciduous molars and absence of premolar teeth, these histological appearances allow distinction of this condition from fibrous dysplasia (FD), segmental hemifacial hypertrophy (SHH) and regional odontodysplasia (ROD).

Dietary zinc alters early inflammatory responses during cutaneous wound healing in weanling CD-1 mice

Zinc deficiency is a well-known health problem associated with delayed wound healing, yet the precise mechanisms that underlie the delay remain unknown. We hypothesized that zinc deficiency delays wound healing as a result of decreased nuclear factor (NF)kappaB activation, reduced expression of proinflammatory cytokines [interleukin (IL)-1beta and tumor necrosis factor (TNF)-alpha], and a decrease in neutrophil infiltration during the early stage of cutaneous wound healing. We used a cutaneous, full-thickness excisional wound model in CD-1 mice to examine the rate of wound closure as well as mRNA levels of inhibitory (I)kappaBalpha, IL-1beta, and TNF-alpha and infiltration of neutrophils at the wound site of mice fed a diet containing <1 (deficient), 50 (control), 500, or 1000 microg zinc/g diet. Zinc deficiency reduced the rate of wound closure and mRNA levels of IL-1beta and TNF-alpha and attenuated infiltration of neutrophils at the wound site compared with controls. Interestingly, zinc supplementation at 1000 microg/g delayed the rate of wound closure and decreased mRNA levels of TNF-alpha and infiltration of neutrophils compared with mice fed the control diet. These findings demonstrate that zinc deficiency and high-dose zinc supplementation delay wound healing as a result of altered inflammatory responses and suggest that adequate zinc supplementation may have beneficial effects on the inflammatory responses to enhance cutaneous wound healing.

Candida albicans triggers interleukin-8 secretion by oral epithelial cells

Oropharyngeal candidiasis is a frequent opportunistic infection associated with immunocompromised hosts. Candida albicans is the principal species responsible for this infection. Production of interleukin-8 (IL-8), by oral epithelial cells can be expected to play a major role in the recruitment and activation of professional phagocytes at the infected site. The purpose of this study was to determine whether C. albicans triggers secretion of IL-8 by oral epithelial cells in vitro and investigate mechanisms of host cell-fungal interactions that trigger such responses. Oral epithelial cell lines (SCC4, SCC15, and OKF6/TERT-2) as well as primary gingival epithelial cells were used. Epithelial cells were cocultured with C. albicans, strains SC5314, ATCC28366 or ATCC32077, for 24-48 hr, and supernatants were analyzed for IL-8 content by ELISA. A germination-deficient mutant (efg1/efg1 cph1/cph1), otherwise isogenic to strain SC5314, was used to assess the requirement for germination in triggering IL-8 responses. In order to ascertain whether direct contact of yeast with host cells is required to trigger cytokine production, epithelial cells were separated from yeast using cell culture inserts. To test whether IL-8 secretion is dependent on IL-1alpha activity, epithelial cells were challenged with viable C. albicans in the presence or absence of neutralizing anti-IL-1alpha antibody or IL-1ra, and IL-8 secretion was measured in the supernatants. All cell lines and primary cultures responded to C. albicans with an increase in IL-8 secretion. IL-8 responses were contact-dependent, strain-specific, required yeast viability and germination into hyphae, and were in part autoregulated by IL-1alpha.

The pathogenesis of oral lichen planus

Both antigen-specific and non-specific mechanisms may be involved in the pathogenesis of oral lichen planus (OLP). Antigen-specific mechanisms in OLP include antigen presentation by basal keratinocytes and antigen-specific keratinocyte killing by CD8(+) cytotoxic T-cells. Non-specific mechanisms include mast cell degranulation and matrix metalloproteinase (MMP) activation in OLP lesions. These mechanisms may combine to cause T-cell accumulation in the superficial lamina propria, basement membrane disruption, intra-epithelial T-cell migration, and keratinocyte apoptosis in OLP. OLP chronicity may be due, in part, to deficient antigen-specific TGF-beta1-mediated immunosuppression. The normal oral mucosa may be an immune privileged site (similar to the eye, testis, and placenta), and breakdown of immune privilege could result in OLP and possibly other autoimmune oral mucosal diseases. Recent findings in mucocutaneous graft-versus-host disease, a clinical and histological correlate of lichen planus, suggest the involvement of TNF-alpha, CD40, Fas, MMPs, and mast cell degranulation in disease pathogenesis. Potential roles for oral Langerhans cells and the regional lymphatics in OLP lesion formation and chronicity are discussed. Carcinogenesis in OLP may be regulated by the integrated signal from various tumor inhibitors (TGF-beta 1, TNF-alpha, IFN-gamma, IL-12) and promoters (MIF, MMP-9). We present our recent data implicating antigen-specific and non-specific mechanisms in the pathogenesis of OLP and propose a unifying hypothesis suggesting that both may be involved in lesion development. The initial event in OLP lesion formation and the factors that determine OLP susceptibility are unknown.

Production and characterization of an in vitro engineered human oral mucosa

The role of epithelial cells in oral pathologies is poorly understood. Until now, most studies have used normal or transformed epithelial cell monolayers, a system that largely bypasses oral mucosal complexity. To overcome these limitations, an engineered human oral mucosa (EHOM) model has been produced and characterized. Following histological and immunohistochemical analyses, EHOM showed well-organized and stratified tissues in which epithelial cells expressed proliferating keratins such as Ki-67, K14, and K19 and also differentiating keratin (K10). In this model, epithelial cells interacted with fibroblasts in the lamina propria by secreting basement membrane proteins (laminins) and by expressing integrins (beta1 and alpha2beta1). Cytokine analyses using cultured supernatants showed that cells in EHOM were able to secrete interleukins (IL) including IL-1beta and IL-8 and tumor necrosis factor alpha (TNF-alpha). Finally, cells in this engineered model were able to secrete different metalloproteinases such as gelatinase-A and gelatinase-B. In conclusion, using tissue engineering technology, we produced well-organized EHOM tissues. It is anticipated that this model will be useful for examining mechanisms involved in oral diseases under controlled conditions by modeling the interactions between mucosa and microorganisms in the oral cavity.

Restraint stress alters the expression of interleukin-1 and keratinocyte growth factor at the wound site: an in situ hybridization study

Stress has a negative impact on wound healing. This murine study evaluated the effect of restraint stress (RST) on interleukin-1 (IL-1) and keratinocyte growth factor-1 (KGF-1) gene expression in cutaneous wounds by in situ hybridization. At day 1, RST mice had reduced frequency of IL-1beta mRNA-expressing fibroblasts compared to control mice. At day 3, RST mice had reduced frequencies of IL-1beta mRNA-expressing leukocytes, KGF-1 mRNA-expressing fibroblasts, and thin proliferating zones of epithelium. At day 5, RST mice had persistent leukocytic foci and reduced granulation tissue. Therefore, stress-induced alterations in cutaneous proinflammatory cytokine and growth factor expression are associated with significant histological changes in healing wounds.

Altered kinetics of IL-1 alpha, IL-1 beta, and KGF-1 gene expression in early wounds of restrained mice

Inflammatory processes that occur after injury contribute to wound closure. Previous studies showed that wounds of restraint-stressed (RST) mice had a reduced number of inflammatory cells and healed more slowly compared to controls. To investigate the molecular mechanisms between stress and wound healing, we studied cutaneous gene expression of IL-1 alpha, IL-1 beta, and KGF-1. Female SKH-1 mice were restrained for 3 days before and for 5 days following placement of cutaneous wounds. Wounds were subjected to competitive RT-PCR. At day 1, RST mice had significantly lower IL-1 beta and KGF-1 mRNA than controls. At day 5, RST mice had significantly higher IL-1 alpha and IL-1 beta mRNA than controls. Treatment of RST mice with the glucocorticoid receptor antagonist RU486 restored IL-1 beta mRNA expression at day 1. Our results suggest that stress induces alterations in the kinetics of cutaneous proinflammatory cytokine and growth factor gene expression which could impair the quality of healing tissues.

Expression of eotaxin, an eosinophil-selective chemokine, parallels eosinophil accumulation in the vesiculobullous stage of incontinentia pigmenti

Incontinentia pigmenti (IP) is an X-linked dominant genodermatosis primarily affecting female children. The initial vesiculobullous stage of IP is characterized clinically by inflammatory papules, blisters, and pustules, and histopathologically by acanthosis, keratinocyte necrosis, epidermal spongiosis and massive epidermal eosinophil infiltration. The cause of this multisystem disease is attributed to the mutations of an X-linked regulatory gene, termed nuclear factor-kappaB essential modulator (NEMO). The exact mechanism of epidermal eosinophil accumulation has not yet been determined. We explored the possible role of an eosinophil-selective, nuclear factor-kappaB-activated chemokine, eotaxin, in the accumulation of eosinophils in the initial stage of the disease. Monoclonal antibody (6H9) specific for human eotaxin strongly labelled the suprabasal epidermis of IP skin, paralleling the upper epidermal accumulation of eosinophils, but did not label the epidermis of normal skin or lesional skin from patients with other inflammatory skin diseases not characterized by prominent eosinophil accumulation, namely dermatitis herpetiformis and selected cases of atopic dermatitis lacking significant numbers of eosinophils. In addition, endothelial cells in lesional skin of IP also exhibited strong expression of eotaxin, which correlated with perivascular and intravascular eosinophil infiltration. We also examined the in vitro effects on epidermally derived eotaxin of several cytokines that were nuclear factor-kappaB-activated and/or known to induce eotaxin expression. In normal human keratinocytes, proinflammatory cytokines either independently (IL-1alpha) or synergistically (tumour necrosis factor-alpha (TNF-alpha)/ interferon-gamma (IFN-gamma) and TNF-alpha/IL-4) up-regulated eotaxin expression. These studies suggest that release of cytokines during the initial inflammatory stage of IP induces epidermal expression of eotaxin, which may play a role in the epidermal accumulation of eosinophils.

IL-1ra and IL-1 production in human oral mucosal epithelial cells in culture: differential modulation by TGF-beta1 and IL-4

Regulatory cytokines mediate the participation of oral mucosal epithelial cells (OMEC) in local immune responses. The aim of this study was to characterize the isoforms of IL-1 receptor antagonist (IL-1ra) in cultured human primary OMECs and to compare its production with that of IL-1 alpha (IL-1alpha) and IL-1 beta (IL-1beta). Western blot analysis showed that IL-1ra was 22 kDa in size hence slightly smaller than monocyte IL-1ra (25 kDa). A minor form of 20 kDa was also found in unstimulated cell culture lysates. In culture supernatants, IL-1 bioactivity increased after IL-1ra neutralization, indicating that the baseline production of IL-1ra is biologically relevant. Immunohistochemistry showed a relation between IL-1ra and involucrin expressions, suggesting that intracytoplasmic IL-1ra may be involved in cell terminal differentiation. In unstimulated culture lysates, there was far more IL-1ra than IL-1alpha and IL-1beta. TGF-beta1 markedly increased the IL-1ra/IL-1beta ratio from 93.6 : 1 to 300 : 1. IL-4, which is generally described as an anti-inflammatory cytokine, increased IL-1 but not IL-1ra production. TNF-alpha increased intracellular production of the three IL-1 members. IL-1ra levels were lower in supernatants than in lysates of cultured cells. Our results show that human OMECs constitutively produce significant amounts of a biologically active form of IL-1ra. TGF-beta1 mu(p)-regulation points to a positive amplification loop and IL-4 to a down-regulation loop, both including Th2 cells and OMECs. They may be important in oral tolerance and IgA production, respectively.

Cytokines detectable in saliva of children as appropriate markers of local immunity of the oral cavity--an approach for the use in air pollution studies

The objective of this study was the detection of proinflammatory markers in saliva to be involved in local immunity of the oral cavity. Therefore saliva of 167 schoolchildren aged 8-10 years were investigated for the presence of interleukin-8 (IL-8), tumour necrosis factor alpha (TNF alpha) and soluble tumour necrosis factor receptor type II (sTNFRII). In saliva of schoolchildren sufficient quantities of IL-8 (302.3-4208.6 pg/ml), TNF alpha (0.3-40.6 pg/ml) and sTNFRII (17.6-931.3 pg/ml) were detectable. IL-8, TNF alpha and sTNFRII revealed significant correlations with each other. Results suggest an immunoregulatory mechanism of IL-8, TNF alpha and TNF-receptor to be of special concern in host defence as well as in maintaining homeostasis of local immunity within the oral cavity. Saliva provides an ideal medium for the detection of proinflammatory markers of the oral cavity with respect to mucosal and granulotype origin and may be employed in air pollution epidemiology, especially with regard to children.

Mechanisms of Actinobacillus actinomycetemcomitans-induced expression of interleukin-8 in gingival epithelial cells

BACKGROUND

Gingival epithelial cells (GEC) are the first cells of the periodontium to encounter known periodontal pathogens, such as Actinobacillus actinomycetemcomitans (A.a.) and, therefore, the role of this pathogen in the initiation of the inflammatory response is critical. However, little is known about the interactions of A.a. with GEC. In the present study, the mechanisms by which extracts from A.a. induced expression of the chemotactic cytokine interleukin-8 (IL-8) in GEC, in vitro, were examined.

METHODS

An established GEC line, PP, was co-cultured with sonicated extracts of A.a. under various in vitro experimental conditions, and the IL-8 secretion was determined with enzyme-linked immunosorbent assay.

RESULTS

A.a. extracts induced a time- and dose-dependent expression of IL-8 from the cells. Dose-response studies indicated that the highest IL-8 secretion (7-fold, P < 0.01) was at the level of 50 micrograms/ml of A.a. extract. Time-course studies revealed a dramatic increase of IL-8 expression after 12 hours of continuous stimulation. Pretreatment with polymyxin B (lipopolysaccharide [LPS] inhibitor) did not reduce the IL-8 expression induced by A.a. extracts (P > 0.10). The introduction of p38 mitogen-activated protein kinase (MAPK) inhibitor SB 203580 markedly inhibited (> 75%, P < 0.01) A.a.-induced expression of IL-8. It is concluded that A.a. extracts upregulated the basal IL-8 expression in GEC.

CONCLUSIONS

The effect was LPS-independent and involved a p38 MAPK signal transducing pathway. Understanding mechanisms of proinflammatory cytokine induction is important in periodontal pathology as it may lead to novel therapeutic approaches for periodontitis, thus controlling host inflammatory responses.

Cytokine gene expression in chronic periodontitis

BACKGROUND

Cytokines play an important rôle in controlling inflammatory processes and tissue homeostasis. Periodontitis, as any other chronic inflammatory disease, results from a disarrangement of host factors, mainly cytokines and the initiating agent. Modulation of the cytokines is not only controlled by the host but also by infecting bacteria and their products.

AIM

In the present study, we examined the cytokine mRNA expression profiles in six patients, each presenting sites affected with (1) severe progressive periodontitis, (2) chronic, but stable periodontal lesions, and (3) with healthy sites. Analysis using a quantitative RT-PCR included IFN-gamma, IL-1beta, IL-2, IL-4, IL-5, IL-6, and TNF-alpha.

MATERIAL AND METHODS

6 patients with chronic periodontitis were following treatment observed for a period of six years for local sites staying healthy, local sites with periodontal pathology but without signs of progression of attachment loss and sites with verified progression were biopsied. The biopsies were lyzed and analyzed for levels of cytokine mRNAs.

RESULTS

Results revealed considerable variation not only between patients, but also between individual sites. Each patient's site has thus to be looked at as an independent entity.

CONCLUSIONS

The local action of cytokines, which is heavily dependent on recruitment, interaction and activation of immunocompetent cells can explain the site-specific nature of cytokine expression. Cytokine data from individual sites together with the local clinical status and data from the literature demonstrate the complexity of periodontal disease pathogenesis. To gain insight to specific mechanisms further studies are needed.

Irritant contact stomatitis: a review of the condition

Several different types of interactions are possible between a chemical, a mixture of chemicals, and associated extrinsic factors (i.e., mechanical irritation) in the oral mucosa. These interactions can be broadly classified as irritative or allergenic in nature. In each case, the pathology usually includes mucosal inflammation. The information compiled and reviewed in this article suggests that, given the broad definition of surface lesions/mucosal abnormalities, there may be a continuum of irritation that can be termed "irritant contact stomatitis." This may be due to the fact that the mouth is lined with highly vascular mucosa that turns over rapidly compared to the skin, and may or may not be covered by keratin. Some regions in the mouth are uniquely sensitive to irritants because they can penetrate through the tissue easily. Key factors involved in the potential development of irritation are: inherent irritation potential of the agent, amount of exposure (concentration, duration, and frequency), ability to penetrate the tissue, and inherent reactivity of the subject as well as other extrinsic factors. Irritation leading to oral mucosal alterations is a common occurrence caused by a wide variety of exposures and insults to the oral cavity. Various irritants such as foods, chemicals, friction, thermal/mechanical injury, metals, spices, and oral care products have been documented to cause irritant reactions in susceptible individuals, particularly if used under exaggerated exposure conditions. It is important to note that most irritation in the oral cavity tends to reverse quickly when the causative agent is removed. Oral irritation is a commonly occurring phenomenon. Thus, it is important that the clinician be aware of the clinical manifestations and etiology of the condition.