Project description:Titanium is a common implant material. However, in some patients titanium implants fail. Macrophages are key cells involved in foreign body response. To identify macrophage response to titainum, primary human macrophages were cultured on porous titanium discs for 6 days We used microarrays to determine the global expression pattern induced by porous titanium in macrophages and identify potential genes involved in implant failure.
Project description:Titanium is a common implant material. However, in some patients titanium implants fail. Macrophages are key cells involved in foreign body response. To identify macrophage response to titainum, primary human macrophages were cultured on polished titanium discs for 6 days We used microarrays to determine the global expression pattern induced by polished titanium in macrophages and identify potential genes involved in implant failure.
Project description:Human gingival epithelial cells (HGEp) and fibroblasts (HGF) are the main cell types of the peri-implant soft-tissue, with HGEp constantly being exposed to bacteria and HGF residing protected in the connective tissue as long as an intact mucosa-implant seal is preserved. Streptococcus oralis belongs to the commensal bacteria, is highly abundant at healthy implant sites, and might exert host modulatory effects on soft-tissue cells as described for other streptococci. Thus, we aimed to investigate the effects of S. oralis biofilm on HGEp as well as HGF. HGEp or HGF were grown on titanium separately and responded to S. oralis biofilm challenge. The cell condition of HGF was dramatically impaired after 4 hours showing a transcriptional inflammatory and stress response. In contrast, S. oralis challenge induced only transcriptional inflammatory response in HGEp with their cell condition remaining unaffected. Subsequently, HGF were susceptible compared to HGEp. The proinflammatory IL-6 was attenuated in HGF and CXCL8 in HGEp indicating a general tissue-protective role of S. oralis, forasmuch as the HGF are not exposed. In conclusion, an intact implant-mucosa interface is a prerequisite so that commensal biofilms can promote homeostasis for tissue protection.
Project description:To combat dental implant-associated infections, there is a need for novel materials which effectively inhibit bacterial biofilm formation. In the present study, a titanium surface functionalization based on the “slippery liquid-infused porous surfaces” (SLIPS) principle was analyzed in an oral flow chamber system. The immobilized liquid layer was stable over 13 days of continuous flow. With increasing flow rates, the surface exhibited a significant reduction in attached biofilm of both the oral initial colonizer Streptococcus oralis and an oral multi-species biofilm composed of S. oralis, Actinomyces naeslundii, Veillonella dispar and Porphyromonas gingivalis. Using single cell force spectroscopy, reduced bacterial adhesion forces on the lubricant layer could be measured. Gene expression patterns in biofilms on SLIPS, on control surfaces and planktonic cultures were also compared. For this purpose, the genome of S. oralis strain ATCC® 9811TM was sequenced using PacBio Sequel technology. Even though biofilm cells showed clear changes in gene expression compared to planktonic cells, no differences could be detected between bacteria on SLIPS and on control surfaces. Therefore, it can be concluded that the ability of liquid-infused titanium to repel biofilms is solely due to weakened bacterial adhesion to the underlying liquid interface.
Project description:Oral health is associated with a symbiotic microbial community and host-microbe homeostasis is maintained by the controlled immune response. Various factors can disrupt this homeostasis. Dysbiosis, which is characterized by increased immune response and a shift in the microbiome, contributes the pathogenesis of peri-implantitis. Peri-implant mucosa and commensal bacteria play important roles in the maintenance of host-microbe homeostasis, but little is known about how they interact. We have therefore investigated the early host-microbe interaction between a commensal multispecies biofilm (Streptococcus oralis, Actinomyces naeslundii, Veillonella dispar, Porphyromonas gingivalis) and peri-implant mucosa at 24 and 48 h. Our in vitro peri-implant mucosa-biofilm model contained organotypic oral mucosa, implant material and biofilm. After 24 h, the biofilm induced a modest innate immune response in the peri-implant mucosa by the upregulation of 5 genes related to immune and inflammatory response and the increased secretion of IL-6 and CCL20. This controlled immune response protected tissue integrity and the peri-implant mucosa remained intact. The secreted antibacterial proteins human β-Defensins-1, -2, and CCL20 controlled the overgrowth of the biofilm by reducing its volume - without affecting the live/dead ratio or bacterial distribution. Thus, host-microbe homeostasis was established within the first 24 h. In contrast, host-microbe homeostasis was disrupted after 48 h. The mucosa was damaged and detached from the implant, due to the induced downregulation of cell adhesion related genes. The immune response was enhanced by upregulation of additional genes related to the immune and inflammatory response and increased secretion of IL-1β, TNF-α, and CCL20. Moreover, bacterial distribution was altered, with an increased proportion of V. dispar. The disrupted host-microbe homeostasis could lead to incipient dysbiosis. This deeper understanding of the early host-microbe interaction at the peri-implant site may provide the basis for new strategies to improve the prevention and therapy of peri-implant diseases.
Project description:In this study the gene expression differences between two titanium surfaces produced at Maastricht University were investigated. These two surfaces were: flat titanium-coated polystyrene and a titanium-coated polystyrene surface imprinted with a pattern selected from an earlier screening study (Ti1018). This pattern was selected based on the osteoinductive properties observed. As a positive control cells on the flat surface were treated with dexamethasone.
Project description:The mucosal penetration area formed by implant placement is critical problems of dental implant treatment, because epithelial barrier is broken and it can become a source of inflammation. To clarify the influence and risk caused by dental implant treatment in peri-implant soft tissue, we compared to gene expression profile of peri-implant soft tissue and oral mucosal tissue with microarray analysis. Both side upper first molars of 4 week-old rat were extracted, and titanium alloy implants were placed only in the left extraction socket. Four weeks after surgery, samples were harvested from left side of peri-implant soft tissue and right side of oral mucosal tissue.