Georg Gassmann

Characterization and analysis of migration patterns of dentospheres derived from periodontal tissue and the palate.

BACKGROUND AND OBJECTIVE Stem cells derived from periodontal and palatal tissues may be useful for regenerative therapies of periodontal tissues. In addition to the use of single periodontium-derived stem cells (pdSCs) and palatal-derived stem cells (paldSCs), the application of pdSC and paldSC dentospheres, providing a pool of vital stem cells, may be a useful approach. As cell migration is a prerequisite for stem cells to regenerate a three-dimensional tissue environment, we characterized pdSCs and paldSCs and investigated the migratory activity of dentospheres within a three-dimensional environment. We also investigated the capacity of the dentospheres to grow on zirconium dioxide surfaces. MATERIAL AND METHODS The capacity of pdSCs and paldSCs to differentiate into the neuronal and osteogenic lineages was proved by RT-PCR and immunohistochemistry through the detection of specific lineage markers, such as alkaline phosphatase, glutamate decarboxylase 1 (also known as GAD67, the 67-kDa isoform of glutamate decarboxylase), neurofilament-M and β-III-tubulin. The expression profile of surface molecules on pdSCs and paldSCs was analyzed by flow cytometry. Adhesion and growth of pdSC/paldSC dentospheres on zirconium dioxide surfaces were determined using confocal laser-scanning microscopy. The migratory behavior of the cells was analyzed using a three-dimensional collagen matrix migration assay. RESULTS Both pdSCs and paldSCs were positive for epidermal growth factor receptor, CC chemokine receptor 2 and CXC chemokine receptor 4 expression and were able to grow on zirconium dioxide surfaces. Cell-migration experiments revealed that both stem-cell populations responded similarly to epidermal growth factor (EGF), monocyte chemotactic protein 1 (MCP-1) and stromal cell-derived factor 1alpha (SDF-1α). Stimulation with EGF resulted in an increased migratory activity of both stem-cell types, whereas the locomotory behavior of the cells was impaired by both MCP-1 and SDF-1α. CONCLUSION Dentospheres represent a pool of vital pdSCs/paldSCs. As a result of the migratory activity demonstrated, along with the capacity to grow on zirconium dioxide surfaces, dentospheres may be useful for regenerative purposes in periodontal tissues.

Influence of enamel matrix derivative on primary CD4+ T-helper lymphocyte migration, CD25 activation, and apoptosis.

BACKGROUND Enamel matrix derivative (EMD) has a low immunogenic potential. To the best of our knowledge, there are no studies on the influence of EMD on lymphocyte migration as a sensitive cellular reaction parameter. This study investigated the influence of EMD on primary T-lymphocyte migration, CD25 activation, and activation-induced cell death. METHODS After immunomagnetic-positive CD4+ lymphocyte separation from peripheral blood taken from three healthy volunteers per trial, the influence of EMD on cell locomotion was assessed in a three-dimensional collagen matrix migration model (CMMM). Direct CD4+ cell contact with EMD at concentrations of 25 and 100 microg/ml was mediated in a one-phase CMMM. We investigated the indirect influence of EMD in a two-phase CMMM: one collagen phase contained 25 and 100 microg EMD/ml, using the same concentrations, and a second adjacent phase contained T lymphocytes. After time-lapse videomicroscopy, the mean locomoting percentage of 30 randomly selected cells was analyzed. Using flow cytometry, CD25 receptor activation was assessed, and annexin V was used for apoptosis detection in lymphocytes challenged with 0, 1, 25, 50, and 100 microg EMD/ml. RESULTS The one-phase CMMM revealed a reduction and the two-phase CMMM showed a dose-dependent increase in the mean locomoting cell percentage (P <0.001). Increasing EMD concentrations resulted in dose-dependent enhanced T-cell CD25 receptor expression and in increasing apoptosis (P <0.001). CONCLUSIONS Our study showed immediate effects of EMD on primary CD4+ lymphocyte migration, CD25 activation, and apoptosis. CD4+ lymphocyte apoptosis may be a further possible background for uneventful early wound healing as seen clinically as the result of EMD application.

Does the Chronically Inflamed Periodontium Harbour Cancer Stem Cells

Trials aiming at isolating cultures and subcultures of cells from the periodontal ligament to uncover special features of such tissue-residing population are related to the past decade [1]. Moreover, the idea of cell-delivery systems, and especially with stem cells, to initiate periodontal regeneration is not new. However, describing suitable animal models for such new techniques is less documented in the literature and sometimes underestimated. The wide range of animal species allows appropriate selection of bio-models for different investigations. Each species has unique similarities and dissimilarities to humans. While many studies could ensure the initiation of periodontal regeneration using stem cells extracted from the periodontium, seeding of human periodontium-derived stem cells (pdSCs) on collagen carriers could induce major features of periodontal regeneration when implanted in experimental periodontal defects in the athymic immunodeficient rat as could be shown in our studies. However, remarkable notifications regarding the results obtained in our studies were the induction of malignant tumors (squamous cell carcinoma) in the majority of investigated animals. Considering the data presented in the literature, our studies seems to be the first that demonstrates the initiation of malignant tumors when using human pdSCs. The patients from whom the pdSCs had been extracted, the animal model used and a possible oncogenic alteration of the pdSCs themselves might all be factors behind the tumors’ initiation. In our present studies, the animal model used and the related experimental periodontal defect, as a heterologous model, could successfully present two important biological features after implantation of pdSCs; namely periodontal repair and tumorigenicity. Although not fully histo-morphometrically assessed in our studies, these features are very important for further investigations and for future more-controlled studies. However, further studies using advanced histological, immunological and genetic techniques are required to assure different supposals presented in the current studies regarding stem cell-based periodontal regeneration and stem cell-tumorigenesis.

Lymphozytenmigration unter Exposition homöopathischer Arzneimittel bei parodontaler Entzündung - eine kontrollierte Pilotstudie

Hintergrund: Viele homöopathische Arzneimittel werden auch für die Behandlung parodontaler Entzündungsprozesse eingesetzt. Über deren Wirkprinzipien ist allerdings nur wenig bekannt. Ziel dieser Studie war es daher, die Effekte verdünnter Substanzen auf die Migrationsaktivität von Lymphozyten bei parodontalen Entzündungsprozessen in vitro zu untersuchen. Material und Methoden: Lymphozyten wurden aus Blutproben von 3 Parodontitispatienten und 3 gematchten gesunden Probanden extrahiert und zusammen mit verdünnten wässrigen Extrakten (D12 and C200) von Mercurius solubilis, Silicea, Sulfur, Tuberculinum oder Placebo in eine Kollagenmatrix eingebettet. Nach einer 60-minütigen mikroskopischen Videoaufzeichnung im Zeitraffer wurden die Migrationsaktivität und -geschwindigkeit der Lyphozyten von je 30 randomisiert ausgewählten Zellen nachvollzogen. Neben univariaten statistischen Verfahren wurde eine SiZer-Zeitreihenanalyse durchgeführt. Ergebnisse: Während bei den Hochverdünnungen (C200) keine bedeutenden Unterschiede zwischen Placebo und den Substanzen gefunden wurden, konnten bei den niedrigen Verdünnungen (D12) im Vergleich zu Placebo starke Effekte beobachtet werden. Die stärksten Effekte wurden in den mit Sulfur D12 exponierten Lyphozyten beobachtet. Während bei den Lymphozyten der Parodontitispatienten ein spezifischer Aktivierungseffekt (mittlere Aktivität: 11,1% (Placebo) vs. 23,8% (Verum)) festgestellt werden konnte, blieb dieser bei den gesunden Probanden aus (25,8% (Placebo) vs. 25,6% (Verum)). Dieser Effekt konnte auch durch die SiZer-Zeitreihenanalyse als signifikant bestätigt werden. Schlussfolgerung: Die Debatte um die Wirkprinzipien von hochverdünnten Substanzen wird immer noch kontrovers geführt. Trotz der geringen Teilnehmerzahl und den damit verbundenen Limitierungen in der Aussagekraft sind insbesondere die Ergebnisse für Sulfur D12 ermutigend. Diese sollten in nachfolgenden Experimenten überprüft und durch weitere immunologische Versuche wie z.B. die Durchflusszytometrie von Zellinien verifiziert werden.BACKGROUND Several homeopathic remedies are applied in the treatment of periodontal inflammation. However, little is known about their basic active principles. Therefore, we aimed at investigating the effects of homeopathic drugs in periodontal inflammation by observing lymphocyte migration activity in vitro. MATERIAL AND METHODS Lymphocytes from blood samples of 3 periodontitis patients and 3 matched healthy volunteers were extracted and embedded in collagen matrix migration assays together with highly diluted (D12 and C200) aqueous extracts from Mercurius solubilis, Silicea, Sulphur, Tuberculinum, or placebo. Lymphocyte migration and lymphocyte speed were observed in a 60-min time frame. Statistical analysis was performed using univariate statistics and SiZer time series analysis. RESULTS While C-dilutions did not reveal clear differences between placebo and substances, strong effects were observed in D-dilutions compared to placebo. The strongest effects were achieved in lymphocytes exposed to Sulfur D12. While most specific effects were observed in Sulphur D12 showing an activating effect on periodontitis patient lymphocytes (mean activity: 11,1% (placebo) vs. 23,8% (verum)), there was no effect in healthy volunteers (25,8% (placebo) vs. 25,6% (verum)). SiZer analysis confirmed this effect to be significant. CONCLUSION The basic active principles of highly diluted substances are still a matter of controversial debate. Although conclusions are limited due to low sample size, results from our pilot study might encourage further investigations on the role of highly diluted Sulphur in the treatment of periodontitis. Apart from a reproduction study with Sulphur, other immunological experiments, i.e. the investigation of cell limes via flow cytometry, should be performed to underpin these results.

Treatment Strategy for Correction of Periodontal Defects Associated with Tongue Piercing: A Case Report

Intraoral piercing has increased in popularity in the last few years. This type of jewelry has been associated with periodontal and muco-gingival defects such as attachment loss and gingival recession. This case report described a 25-year-old female presented to the clinic of Periodontics at Witten/Herdecke University in Witten, Germany, with a tongue stud placed through the mid-dorsum of her tongue. The lower left central (LL1) and lower right central (LR1) incisors exhibited 6 mm and 5 mm lingual probing depth, 4mm and 3.5mm lingual recession respectively and localized radiographic bone loss in the mid-half of the roots. The treatment strategy consisted of removal of the tongue piercing, professional prophylaxis, oral hygiene instructions and an open-flap surgery of the lingual anterior region of the mandible with the application of enamel matrix derivative (EMD) and bone graft material. Results: At the 1-, 3- and 7-month recall visits, the patient’s oral hygiene has been improved, and the attachment loss appears to have stabilized. It is clear that the tongue piercing might be a risk factor for local periodontal complications.