Role of innate host defense proteins in oral cancerogenesis.

It is nowadays well accepted that chronic inflammation plays a pivotal role in tumor initiation and progression. Under this aspect, the oral cavity is predestined to examine this connection because periodontitis is a highly prevalent chronic inflammatory disease and oral squamous cell carcinomas are the most common oral malignant lesions. In this review, we describe how particular molecules of the human innate host defense system may participate as molecular links between these two important chronic noncommunicable diseases (NCDs). Specific focus is directed toward antimicrobial polypeptides, such as the cathelicidin LL-37 and human defensins, as well as S100 proteins and alarmins. We report in which way these peptides and proteins are able to initiate and support oral tumorigenesis, showing direct mechanisms by binding to growth-stimulating cell surface receptors and/or indirect effects, for example, inducing tumor-promoting genes. Finally, bacterial challenges with impact on oral cancerogenesis are briefly addressed.

Effects of histone acetyltransferase (HAT) and histone deacetylase (HDAC) inhibitors on proliferative, differentiative, and regenerative functions of Toll-like receptor 2 (TLR-2)-stimulated human dental pulp cells (hDPCs).

OBJECTIVES: This in vitro study aimed to modify TLR-2-mediated effects on the paracrine, proliferative, and differentiation potentials of human dental pulp-derived cells using histone acetyltransferase (HAT) and histone deacetylase (HDAC) inhibitors. MATERIALS AND METHODS: Cell viability was assessed using the XTT assay. Cells were either treated with 10 µg/ml Pam3CSK4 only, or pre-treated with valproic acid (VPA) (3 mM), trichostatin A (TSA) (3 µM), and MG-149 (3 µM) for a total of 4 h and 24 h. Control groups included unstimulated cells and cells incubated with inhibitors solvents only. Transcript levels for NANOG, OCT3-4, FGF-1 and 2, NGF, VEGF, COL-1A1, TLR-2, hßD-2 and 3, BMP-2, DSPP, and ALP were assessed through qPCR. RESULTS: After 24 h, TSA pre-treatment significantly upregulated the defensins and maintained the elevated pro-inflammatory cytokines, but significantly reduced healing and differentiation genes. VPA significantly upregulated the pro-inflammatory cytokine levels, while MG-149 significantly downregulated them. Pluripotency genes were not significantly affected by any regimen. CONCLUSIONS: At the attempted concentrations, TSA upregulated the defensins gene expression levels, and MG-149 exerted a remarkable anti-inflammatory effect; therefore, they could favorably impact the immunological profile of hDPCs. CLINICAL RELEVANCE: Targeting hDPC nuclear function could be a promising option in the scope of the biological management of inflammatory pulp diseases.

Feasibility of aponeurectomy in combination with perioperative 192Ir high dose rate brachytherapy for Dupuytren's disease.

PURPOSE: Partial aponeurectomy (PA) is a standard procedure for Dupuytren's contracture (DC). Here we report a novel approach using surgery combined with perioperative high dose rate (192Ir-HDR) brachytherapy. METHODS AND PATIENTS: From March 2018 until February 2020, thirteen rays of 6 patients with Dupyutren's contractures underwent PA followed by HDR brachytherapy. After removal of fibrous tissue and mobilization of the tendons, one to three catheters per patient were placed intraoperatively. Immediately after surgery, a planning computer tomography with 3D-planning was performed. Then 10-12 Gy were given to 0-2 mm from the catheters' surface and the catheters were removed 6-12 h after brachytherapy. RESULTS: No complications were observed. The mean contractures were reduced from 55.4° (standard error SE 19.6) to 15.4° (SE 6.7; p < 0.01). One patient showed progressive fibrosis of a nontreated ray during follow-up. CONCLUSIONS: HDR brachytherapy in combination with surgery is feasible and harbors the potential for combined modality therapy to reduce relapse rates of advanced or relapsing DC. Controlled studies are warranted to investigate the role of bimodal therapy compared with PA alone.

In vitro cytotoxicity of different dental resin-cements on human cell lines.

Adhesive resin-cements are increasingly used in modern dentistry. Nevertheless, released substances from resin materials have been shown to cause cellular toxic effects. Disc-shaped specimens from 12 different resin cements and one conventional zinc phosphate cement were prepared and used for direct stimulation of five different human cell lines via transwell cell culture system or in an indirect way using conditioned cell culture media. Cytotoxicity was determined using LDH and BCA assays. All tested cements led to a decrease of cell viability but to a distinct extent depending on cell type, luting material, and cytotoxicity assay. In general, cements exhibited a more pronounced cytotoxicity in direct stimulation experiments compared to stimulations using conditioned media. Interestingly, the conventional zinc phosphate cement showed the lowest impact on cell viability. On cellular level, highest cytotoxic effects were detected in osteoblastic cell lines. All resin cements reduced cell viability of human cells with significant differences depending on cell type and cement material. Especially, osteoblastic cells demonstrated a tremendous increase of cytotoxicity after cement exposure. Although the results of this in vitro study cannot be transferred directly to a clinical setting, it shows that eluted substances from resin cements may disturb osteoblastic homeostasis that in turn could lead to conditions favoring peri-implant bone destruction. Thus, the wide use of resin cements in every clinical situation should be scrutinized. A correct use with complete removal of all cement residues and a sufficient polymerization should be given the utmost attention in clinical usage.

Unusual Manifestation of Chronic Lymphocytic Leukemia in the Hand.

Chronic lymphocytic leukemia (CLL) involving the hand, especially with bone involvement, is extremely rare. We report a case of a 62-year-old man, with a 4-year history of a subclinical CLL, presenting with chronic swelling and pain over the dorsal surface of the right hand, mimicking an infectious process. There was no clinical response to broad-spectrum antibiotics and topical corticosteroid therapy. Imaging was inconclusive. A tissue biopsy revealed a manifestation of the underlying leukemia. This case highlights the need to consider uncommon etiologies for atypical clinical presentations.

The Presence of Yin-Yang Effects in the Migration Pattern of Staurosporine-Treated Single versus Collective Breast Carcinoma Cells.

BACKGROUND: Staurosporine-dependent single and collective cell migration patterns of breast carcinoma cells MDA-MB-231, MCF-7, and SK-BR-3 were analysed to characterise the presence of drug-dependent migration promoting and inhibiting yin-yang effects. METHODS: Migration patterns of various breast cancer cells after staurosporine treatment were investigated using Western blot, cell toxicity assays, single and collective cell migration assays, and video time-lapse. Statistical analyses were performed with Kruskal-Wallis and Fligner-Killeen tests. RESULTS: Application of staurosporine induced the migration of single MCF-7 cells but inhibited collective cell migration. With the exception of low-density SK-BR-3 cells, staurosporine induced the generation of immobile flattened giant cells. Video time-lapse analysis revealed that within the borderline of cell collectives, staurosporine reduced the velocity of individual MDA-MB-231 and SK-BR-3, but not of MCF-7 cells. In individual MCF-7 cells, mainly the directionality of migration became disturbed, which led to an increased migration rate parallel to the borderline, and hereby to an inhibition of the migration of the cell collective as a total. Moreover, the application of staurosporine led to a transient activation of ERK1/2 in all cell lines. CONCLUSION: Dependent on the context (single versus collective cells), a drug may induce opposite effects in the same cell line.

Hyperspectral imaging of tissue perfusion and oxygenation in wounds: assessing the impact of a micro capillary dressing.

OBJECTIVE: Experimental tests of non-invasive multi- or hyperspectral imaging (HSI) systems reveal the high potential of support for medical diagnostic purposes and scientific biomedical analysis. Until now the use of HSI technologies for medical applications was limited by complex and overly sophisticated systems. We present a new and compact HSI-camera that could be used in normal clinical practice. METHOD: We assessed the use of the HSI system on the hands of 10 healthy volunteers, looking at control parameters, and those following venous occlusion, arterial occlusion and reperfusion, including tissue oxygenation, tissue haemoglobin index, perfusion in 4-6mm depth=near infrared spectroscopy (NIR), and tissue water index. Pseudo colours used ranged from 0% (blue) to 100% (red). We also assessed differences in the wounds of three patients. RESULTS: The results show good potential in all parameters in the healthy volunteers, which had high conformity with validated reference oximetry measurements. In three wounds, different levels of oxygenation were identified in the wound area, although interpretation of these results is complex. In Cases 2 and 3, following the application of a micro capillary dressing, improvements were seen in perfusion and reduction of the tissue water index (TWI). CONCLUSION: The camera system proved to be quick, flexible and yielded data with high spatial and spectral resolution. These data will be used to perform a power analysis for a randomised controlled study.

Ghrelin promotes oral tumor cell proliferation by modifying GLUT1 expression.

In our study, ghrelin was investigated with respect to its capacity on proliferative effects and molecular correlations on oral tumor cells. The presence of all molecular components of the ghrelin system, i.e., ghrelin and its receptors, was analyzed and could be detected using real-time PCR and immunohistochemistry. To examine cellular effects caused by ghrelin and to clarify downstream-regulatory mechanisms, two different oral tumor cell lines (BHY and HN) were used in cell culture experiments. Stimulation of either cell line with ghrelin led to a significantly increased proliferation. Signal transduction occurred through phosphorylation of GSK-3ß and nuclear translocation of ß-catenin. This effect could be inhibited by blocking protein kinase A. Glucose transporter1 (GLUT1), as an important factor for delivering sufficient amounts of glucose to tumor cells having high requirements for this carbohydrate (Warburg effect) was up-regulated by exogenous and endogenous ghrelin. Silencing intracellular ghrelin concentrations using siRNA led to a significant decreased expression of GLUT1 and proliferation. In conclusion, our study describes the role for the appetite-stimulating peptide hormone ghrelin in oral cancer proliferation under the particular aspect of glucose uptake: (1) tumor cells are a source of ghrelin. (2) Ghrelin affects tumor cell proliferation through autocrine and/or paracrine activity. (3) Ghrelin modulates GLUT1 expression and thus indirectly enhances tumor cell proliferation. These findings are of major relevance, because glucose uptake is assumed to be a promising target for cancer treatment.

A novel blue light laser system for surgical applications in dentistry: evaluation of specific laser-tissue interactions in monolayer cultures.

OBJECTIVES: The objective of this study was to examine a new blue light diode laser system (445 nm) for dental soft tissue surgery on cellular level. MATERIALS AND METHODS: An in vitro cell culture model was established to evaluate the effects of the 445-nm diode laser in comparison to an established infrared diode laser (IR). Monolayer cell cultures were irradiated and wound healing was morphometrically measured. Fluorescence staining was used for proof of potential DNA double-strand breaks as well as cytoskeleton alterations. Cellular live/dead discrimination was performed and temperature development during laser irradiation was measured with a thermographic infrared camera. RESULTS: A characteristic zone formation was detected after irradiation with both wavelengths. Despite a larger wound area after irradiation with 445 nm, due to its higher temperature development, this laser system showed a faster wound healing in comparison to the IR laser. No increase of devitalized cells was documented with higher distances between laser tip and cell layer and thus without thermal interaction. Neither cytoskeleton alteration nor DNA double-strand breaks could be recorded after irradiation in non-contact mode. CONCLUSIONS: The blue diode laser system demonstrated an excellent direct thermal coupling to cells and tissues without side effects even by reduced power settings. CLINICAL RELEVANCE: The blue diode laser seems to be a promising technology for clinical application due to high absorption of blue light without major side effects in adjacent tissues even by reduced power settings.

Oncogenic relevant defensins: expression pattern and proliferation characteristics of human tumor cell lines.

The objective of this study was to investigate gene expression levels of oncogenic relevant human defensins and their impact on proliferation rates of 29 cell lines derived from main types of different tumor origins. Differential gene expression analysis of human defensins was performed by real-time PCR experiments. The proliferation rate of tumor cells that had been cultivated in the absence or presence of biologically active peptides was analyzed with a lactate dehydrogenase assay kit. At least one member of the defensin family was expressed in each tumor cell line, whereby α-defensin (DEFA1), DEFA2, or DEFA3 transcripts could be ubiquitously detected. Cell lines of neural origin (glioma, neuroblastoma, and small-cell lung carcinoma) expressed far less human ß-defensins (hBDs) in comparison to other tumor types. The expression level of a specific defensin in various cell lines could vary by more than five orders of magnitude. Compensatory mechanisms on the expression levels of the different defensins could not be strictly observed. Only in 3 out of 29 tumor cell lines the proliferation rate was affected after defensin stimulation. The variable appearance of defensins, as well as the cell line-restricted functional activity, argues for the integration of defensins in complex cellular and molecular networks that tolerate rather flexible expression patterns.

Cellular Distribution and Gene Expression Pattern of Metastasin (S100A4), Calgranulin A (S100A8), and Calgranulin B (S100A9) in Oral Lesions as Markers for Molecular Pathology.

The objective of this study was to analyze cellular localization and expression levels of oncologic relevant members of the S100 family in common oral lesions.Biopsies of various oral lesions were analyzed. S100A4 showed a higher expression rate in leukoplakias and oral squamous cell carcinomas. Transcript levels of S100A8 and S100A9 were significantly decreased in malignant OSCCs. A correlation could be drawn between the expression levels of these genes and the pathological characteristics of the investigated lesions. S100A4, A8, and A9 proteins represent promising marker genes to evaluate the risk potential of suspicious oral lesions in molecular pathology.

Staurosporine analogs promote distinct patterns of process outgrowth and polyploidy in small cell lung carcinoma cells.

We have recently shown that staurosporine mediates the conversion of small cell lung carcinoma (SCLC) cells into a neuron-like process-bearing phenotype. Here, we have extended these studies to the staurosporine analogs K252a, lestaurtinib, PKC412, stauprimide, and UCN-01 and analyzed their influence on process extension, cell cycle distribution, and induction of polyploidy in four SCLC cell lines. In GLC-2 cells, all compounds provoked extensive process formation with the exception of PKC412 that showed no response. In H1184 cells, process formation was predominantly induced by staurosporine and, to lesser extent, in lestaurtinib-, stauprimide-, and UCN-01-treated cells. In the presence of K252a or PKC412, cells became bipolar and spindle shaped or showed pronounced cell flattening. In GLC-36 and SCLC-24H cells, only cell flattening was detectable. Process formation was reversible upon drug removal as shown for GLC-2 and H1184 cells. Fluorescence-activated cell sorting (FACS) and fluorescence in situ hybridization (FISH) analysis indicated the induction of polyploidy in all staurosporine and in two out of four stauprimide-treated SCLC cell lines. For other staurosporine analogs, polyploidy was observed only in UCN-01-treated GLC-36 cells and in K252a-treated H1184 and GLC-36 cells. The presence of staurosporine or its analogs did not alter the constitutive activation pattern of the canonical Akt/PI3K or MEK/extracellular signal-regulated kinase (ERK)1/2 signaling pathways nor could we detect an influence of stauprimide application on the expression level of the c-Myc oncogene. These data demonstrate that in SCLC cells, albeit a higher substrate specificity, staurosporine analogs can induce staurosporine-comparable effects.

Regulation of NAMPT in human gingival fibroblasts and biopsies.

Adipokines, such as nicotinamide phosphoribosyltransferase (NAMPT), are molecules, which are produced in adipose tissue. Recent studies suggest that NAMPT might also be produced in the tooth-supporting tissues, that is, periodontium, which also includes the gingiva. The aim of this study was to examine if and under what conditions NAMPT is produced in gingival fibroblasts and biopsies from healthy and inflamed gingiva. Gingival fibroblasts produced constitutively NAMPT, and this synthesis was significantly increased by interleukin-1ß and the oral bacteria P. gingivalis and F. nucleatum. Inhibition of the MEK1/2 and NFκB pathways abrogated the stimulatory effects of F. nucleatum on NAMPT. Furthermore, the expression and protein levels of NAMPT were significantly enhanced in gingival biopsies from patients with periodontitis, a chronic inflammatory infectious disease of the periodontium, as compared to gingiva from periodontally healthy individuals. In summary, the present study provides original evidence that gingival fibroblasts produce NAMPT and that this synthesis is increased under inflammatory and infectious conditions. Local synthesis of NAMPT in the inflamed gingiva may contribute to the enhanced gingival and serum levels of NAMPT, as observed in periodontitis patients. Moreover, local production of NAMPT by gingival fibroblasts may represent a possible mechanism whereby periodontitis may impact on systemic diseases.

Functional characterization of the parathyroid hormone 1 receptor in human periodontal ligament cells.

OBJECTIVES: Intermittent parathyroid hormone (PTH) exerts anabolic effects on bone and has been approved for osteoporosis therapy. The dual actions of PTH are mediated primarily through the parathyroid hormone 1 receptor (PTH1R). Upon ligand binding, PTH1R activates diverse signaling pathways, including cAMP/protein kinase A (PKA)- and phospholipase C/protein kinase C (PLC/PKC)-dependent pathways. PTH1R has been abundantly studied in bone cells. Knowledge on PTH1R characteristics and physiology in periodontal ligament (PDL) cells is still in its infancy. MATERIALS AND METHODS: We characterized PTH1R in PDL cells in terms of its cellular localization, binding affinity, and signal transduction and compared these characteristics to those of MG63 osteoblast-like cells. RESULTS: PTH1R mRNA/protein was identified in PDL and MG63 cells. PTH1R was mainly localized on the plasma membrane, in vesicular structures inside the cell, and, to some extent, in the nucleus of both cell types. Binding characteristics of PTH1R were cell type specific, with PDL cells demonstrating a lower binding affinity. The response of cAMP and active PKC production in MG63 cells was dose dependent with increasing PTH(1-34) concentration, whereas in PDL cells, it was regulated biphasically. However, we observed a cross talk between the cAMP/PKA and PLC/PKC signaling pathways, which were regulated diametrically opposed at a given concentration of PTH(1-34). CONCLUSION: These data indicate that, albeit the similarity in its subcellular distribution, PTH1R in PDL cells exhibits characteristics different from those in MG63 cells, pointing to the cell type specificity of this receptor. CLINICAL RELEVANCE: The findings further elucidate the characteristics of PTH action in dental tissues and widen the theoretical basis for the development of anabolic treatment strategies.

Verification of IL-17A and IL-17F in oral tissues and modulation of their expression pattern by steroid hormones.

Interleukin (IL-) 17A and IL-17F mediate immune responses by inducing both proinflammatory and regulatory mechanisms. Immunological processes are modulated by steroids, which also affect periodontal pathophysiology. It was the aim of this study to investigate the expression profile of IL-17A and IL-17F in periodontal tissues and to analyze the significance of testosterone and estradiol on IL-17 expression in periodontal cells. In vivo incidence of IL-17A and IL-17F was immunohistochemically quantified in human periodontal tissues. In vitro expression of IL-17A and IL-17F was analyzed in human gingival epithelial cells, gingival fibroblasts and periodontal ligament cells via qRT-PCR. Gene expression alterations of IL-17 were assessed following challenge with testosterone and 17ß-estradiol under simulated inflammatory conditions (±IL-1ß). Analyses proved IL-17 expression in periodontal hard and soft tissues and in resident cells, showing distinct patterns for the subtypes IL-17A and IL-17F. IL-17F was discriminatively regulated by testosterone and 17ß-estradiol in resident periodontal cells.

Potential immune modularly role of glycine in oral gingival inflammation.

Gingival epithelial cells (GECs) represent a physical barrier against bacteria and are involved in the processes of innate immunity. Recently, an anti-inflammatory and immune-modulatory effect of the amino acid glycine has been demonstrated. However, there is only little information about the immune-modulatory effects of glycine in oral tissues. This study aimed to investigate the existence and role of the glycine receptor in gingival tissue analyzing tissues/cells from extracted human molars via immunohistochemical analysis. In vitro, GECs were challenged by inflammatory conditions with IL-1 ß alone or in combination with glycine and analyzed for cytokine expression of IL6/IL8 via real-time PCR. On protein level, the effect of nuclear translocalization of NF κ B protein p65 was analyzed using immunofluorescence analysis. A distinct proof of the GlyR in oral gingival tissue and keratinocytes could be demonstrated. Isolated challenge of the keratinocytes with IL-1 ß as well as with glycine resulted in an upregulation of IL6 and IL8 mRNA expression and activation of NF κ B pathway. The presence of glycine in combination with the inflammatory stimulus led to a significant decrease in inflammatory parameters. These results indicate a possible anti-inflammatory role of glycine in gingival inflammation and encourage further research on the utility of glycine in the prevention or therapy of inflammatory periodontitis.

Immunohistochemical Analysis of S100 Proteins in Normal and Irreversibly Inflamed Human Dental Pulps.

INTRODUCTION: S100 proteins convey important roles in innate immune responses to infection and regenerative processes. However, their role in inflammatory or regenerative processes of the human dental pulp is poorly elucidated. The aim of the present study was to detect, localize, and compare the occurrence of 8 S100 proteins in normal, symptomatic, and asymptomatic irreversibly inflamed dental pulp specimens. METHODS: Human dental pulp specimens from 45 individuals were clinically assigned to 3 groups of pulpal diagnosis: normal pulp (NP, n = 17), asymptomatic irreversible pulpitis (AIP, n = 13), and symptomatic irreversible pulpitis (SIP, n = 15). The specimens were prepared and immunohistochemically stained for proteins S100A1, -A2, -A3, -A4, -A6, -A7, -A8, and -A9. Staining was classified using semiquantitative analysis and a 4-degree staining score (ie, no, decent, medium, and intense staining) at 4 different anatomic or functional regions (ie, the odontoblast layer [OL], pulpal stroma [PS], border area of calcifications [BAC], and vessel walls). The distribution of staining degrees between the 3 diagnostic groups was calculated using the Fisher exact text (P ≤ .05) at the 4 regions. RESULTS: Significant differences in staining were observed mainly in the OL and PS and at the BAC. The most significant differences were detected in the PS and when comparing NP with 1 of the 2 irreversibly inflamed pulpal tissues (AIP or SIP). The inflamed tissues were then invariably stained more intensely than their normal counterparts at this location (S100A1, -A2, -A3, -A4, -A8, and -A9). In the OL, NP tissue was significantly stronger stained for S100A1, -A6, -A8, and -A9 compared with SIP and for S100A9 when compared with AIP. Differences between AIP and SIP in direct comparison were rare and were found only for 1 protein (S100A2) at the BAC. Also, at the vessel walls, only 1 statistical difference in staining was observed (SIP was stronger stained than NP for protein S100A3). CONCLUSIONS: The occurrence of proteins S100A1, -A2, -A3, -A4, -A6, -A8, and -A9 is significantly altered in irreversibly inflamed compared with normal dental pulp tissue at different anatomic localizations. Some members of S100 proteins obviously participate in focal calcification processes and pulp stone formation of the dental pulp.

Targeting of Glucose Transport and the NAD Pathway in Neuroendocrine Tumor (NET) Cells Reveals New Treatment Options.

(1) Background: the potency of drugs that interfere with glucose metabolism, i.e., glucose transporters (GLUT) and nicotinamide phosphoribosyltransferase (NAMPT) was analyzed in neuroendocrine tumor (NET, BON-1, and QPG-1 cells) and small cell lung cancer (SCLC, GLC-2, and GLC-36 cells) tumor cell lines. (2) Methods: the proliferation and survival rate of tumor cells was significantly affected by the GLUT-inhibitors fasentin and WZB1127, as well as by the NAMPT inhibitors GMX1778 and STF-31. (3) Results: none of the NET cell lines that were treated with NAMPT inhibitors could be rescued with nicotinic acid (usage of the Preiss-Handler salvage pathway), although NAPRT expression could be detected in two NET cell lines. We finally analyzed the specificity of GMX1778 and STF-31 in NET cells in glucose uptake experiments. As previously shown for STF-31 in a panel NET-excluding tumor cell lines, both drugs specifically inhibited glucose uptake at higher (50 µM), but not at lower (5 µM) concentrations. (4) Conclusions: our data suggest that GLUT and especially NAMPT inhibitors are potential candidates for the treatment of NET tumors.

Human α-defensin (DEFA) gene expression helps to characterise benign and malignant salivary gland tumours.

BACKGROUND: Because of the infrequence of salivary gland tumours and their complex histopathological diagnosis it is still difficult to exactly predict their clinical course by means of recurrence, malignant progression and metastasis. In order to define new proliferation associated genes, purpose of this study was to investigate the expression of human α-defensins (DEFA) 1/3 and 4 in different tumour entities of the salivary glands with respect to malignancy. METHODS: Tissue of salivary glands (n=10), pleomorphic adenomas (n=10), cystadenolymphomas (n=10), adenocarcinomas (n=10), adenoidcystic carcinomas (n=10), and mucoepidermoid carcinomas (n=10) was obtained during routine surgical procedures. RNA was extracted according to standard protocols. Transcript levels of DEFA 1/3 and 4 were analyzed by quantitative realtime PCR and compared with healthy salivary gland tissue. Additionally, the proteins encoded by DEFA 1/3 and DEFA 4 were visualized in paraffin-embedded tissue sections by immunohistochemical staining. RESULTS: Human α-defensins are traceable in healthy as well as in pathological altered salivary gland tissue. In comparison with healthy tissue, the gene expression of DEFA 1/3 and 4 was significantly (p<0.05) increased in all tumours - except for a significant decrease of DEFA 4 gene expression in pleomorphic adenomas and a similar transcript level for DEFA 1/3 compared to healthy salivary glands. CONCLUSIONS: A decreased gene expression of DEFA 1/3 and 4 might protect pleomorphic adenomas from malignant transformation into adenocarcinomas. A similar expression pattern of DEFA-1/3 and -4 in cystadenolymphomas and inflamed salivary glands underlines a potential importance of immunological reactions during the formation of Warthin's tumour.

Anti-inflammatory effects of EMD in the presence of biomechanical loading and interleukin-1ß in vitro.

Enamel matrix derivative (EMD) used to promote periodontal regeneration has been shown to exert anti-inflammatory effects. This in vitro study was performed to investigate if the anti-inflammatory actions of EMD are modulated by the local cellular environment, such as inflammation or occlusal, i.e., biomechanical, loading. Human periodontal ligament cells were seeded on BioFlex plates and incubated with EMD under normal, inflammatory, and biomechanical loading conditions for 1 and 6 days. In order to mimic inflammatory and biomechanical loading conditions in vitro, cells were stimulated with interleukin (IL)-1ß and exposed to dynamic tensile strain, respectively. The gene expression of IL-1ß, IL-1 receptor antagonist (IL-1RN), IL-6, IL-8, IL-10, and cyclooxygenase (COX)-2 was analyzed by real-time RT-PCR and the IL-6 protein synthesis by enzyme-linked immunoassay. For statistical analysis, Student's t test, ANOVA, and post-hoc comparison tests were applied (p < 0.05). EMD downregulated significantly the expression of IL-1ß and COX-2 at 1 day and of IL-6, IL-8, and COX-2 at 6 days in normal condition. In an inflammatory environment, the anti-inflammatory actions of EMD were significantly enhanced at 6 days. In the presence of low biomechanical loading, EMD caused a downregulation of IL-1ß and IL-8, whereas high biomechanical loading significantly abrogated the anti-inflammatory effects of EMD at both days. Neither IL-1RN nor IL-10 was upregulated by EMD. These data suggest that high occlusal forces may abrogate anti-inflammatory effects of EMD and should, therefore, be avoided immediately after the application of EMD to achieve best healing results.