Behavior Of Human Gingival Fibroblasts Research Articles

Modulation of human dermal microvascular endothelial cell and human gingival fibroblast behavior by micropatterned silica coating surfaces for zirconia dental implant applications

Dental ceramic implants have shown superior esthetic behavior and the absence of induced allergic disorders when compared to titanium implants. Zirconia may become a potential candidate to be used as an alternative to titanium dental implants if surface modifications are introduced. In this work, bioactive micropatterned silica coatings were produced on zirconia substrates, using a combined methodology of sol–gel processing and soft lithography. The aim of the work was to compare the in vitro behavior of human gingival fibroblasts (HGFs) and human dermal microvascular endothelial cells (HDMECs) on three types of silica-coated zirconia surfaces: flat and micropatterned (with pillars and with parallel grooves). Our results showed that cells had a higher metabolic activity (HGF, HDMEC) and increased gene expression levels of fibroblast-specific protein-1 (FSP-1) and collagen type I (COL I) on surfaces with pillars. Nevertheless, parallel grooved surfaces were able to guide cell growth. Even capillary tube-like networks of HDMEC were oriented according to the surface geometry. Zirconia and silica with different topographies have shown to be blood compatible and silica coating reduced bacteria adhesion. All together, the results indicated that microstructured bioactive coating seems to be an efficient strategy to improve soft tissue integration on zirconia implants, protecting implants from peri-implant inflammation and improving long-term implant stabilization. This new approach of micropatterned silica coating on zirconia substrates can generate promising novel dental implants, with surfaces that provide physical cues to guide cells and enhance their behavior.

Immobilization of Ag nanoparticles/FGF‐2 on a modified titanium implant surface and improved human gingival fibroblasts behavior

The objective of this study was to form a rapid and firm soft tissue sealing around dental implants that resists bacterial invasion. We present a novel approach to modify Ti surface by immobilizing Ag nanoparticles/FGF-2 compound bioactive factors onto a titania nanotubular surface. The titanium samples were anodized to form vertically organized TiO(2) nanotube arrays and Ag nanoparticles were electrodeposited onto the nanotubular surface, on which FGF-2 was immobilized with repeated lyophilization. A uniform distribution of Ag nanoparticles/FGF-2 was observed on the TiO(2) nanotubular surface. The L929 cell line was used for cytotoxicity assessment. Human gingival fibroblasts (HGFs) were cultured on the modified surface for cytocompatibility determination. The Ag/FGF-2 immobilized samples displayed excellent cytocompatibility, negligible cytotoxicity, and enhanced HGF functions such as cell attachment, proliferation, and ECM-related gene expression. The Ag nanoparticles also exhibit some bioactivity. In conclusion, this modified TiO(2) nanotubular surface has a large potential for use in dental implant abutment.

The impact of defined polyglycolide scaffold structure on the proliferation of gingival fibroblasts in vitro: a pilot study

The postoperative apical growth of epithelium on teeth is a common complication of surgical periodontal therapy. Absorbable textile scaffolds, placed between the operated tooth and its nearby tissues, are considered to serve as a mechanical barrier and prevent undesired apical epithelial growth. They allow local regeneration and the new formation of human gingival fibroblasts when the scaffolds are colonized with autologous cells. The aim of this study was to examine the proliferation behavior of human gingival fibroblasts on polyglycolic acid (PGA) fleeces with various structural characteristics. The PGA fleeces varied in the following characteristics: thickness (1.0-5.0 mm), porosity (85%-98%), mass-area ratio (56.6-166.9 g/m(2)), and texture. The proliferation of incorporated autologous cells was analyzed by determining the number of live cells, the total absorbed protein, and the degree of cell proliferation. The results showed that fleece made from Knit-de-Knit textured fibers with a porosity of about 90%, a mass-area between 58 and 84 g/m(2), and a thickness of 1.5 mm was most suitable as a scaffold structure. This fleece showed the highest cell proliferation rate and was superior to fleeces with other structural characteristics. Textile PGA fleece seems to be suitable as a scaffold structure for human gingival fibroblasts. The structural parameters of the fleece have a significant influence on the proliferation of the cells.

Untersuchungen zum Design dreidimensionaler textiler Trägermaterialien für das Tissue Engineering in vitro: eine Pilotstudie / Structure design examinations of three-dimensional textile scaffolds employed for tissue engineering in vitro: a pilot study

Postoperative apical growth of epithelium on teeth is a common complication of surgical periodontal therapy. Absorbable textile scaffolds, placed between the operated tooth and its nearby tissues, are considered to serve as a mechanical barrier and prevent undesired apical epithelial growth. They allow local regeneration and new formation of human gingival fibroblasts when the scaffolds are colonized with autologous cells. The aim of this study was to examine proliferation behavior of human gingival fibroblasts on polyglycolic acid (PGA) fleeces with various structural characteristics. The characteristics of the PGA fleeces varied as follows: thickness (1.0-5.0 mm), porosity (85-98%), area mass (56.6-166.9 g/m(2)), and texture. Proliferation of incorporated autologous cells was analyzed by determining the number of live cells, the total absorbed protein, and the degree of cell proliferation. Textile PGA fleeces seem to be suitable as scaffold structures for human gingival fibroblasts. Results showed that structural parameters of fleeces have a significant influence on cell proliferation. Our results showed that a fleece made from knit-de-knit fibers with a porosity of 90% and a thickness of 1.5 mm was most suitable as a scaffold structure and had the highest cell proliferation rate and was superior to fleeces with other structural characteristics.

Advanced Glycation of Type I Collagen and Fibronectin Modifies Periodontal Cell Behavior

Advanced glycation end products (AGEs) have been linked to pathogenic mechanisms of diabetes mellitus. However, little is known about the contribution of protein glycation to periodontal disease in patients with diabetes. Therefore, this study investigated whether glycation of type I collagen (COLI) and fibronectin (FN) modified the behavior of human gingival fibroblasts (hGFs) and periodontal ligament fibroblasts (hPDLs). Procedures for rapid in vitro glycation of COLI and FN used methylglyoxal (MG). Formation of AGEs was analyzed by changes in protein migration using sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blotting with antibodies specific for MG-glycated proteins. Experiments then characterized the effects of glycated FN and COLI on the behavior of hGFs and hPDLs. MG glycated COLI and FN in <6 hours. Confirming the specificity of the reactions, antibodies specific for MG-induced AGEs reacted with glycated FN and COLI but not with control proteins. In cell culture experiments, glycated FN was significantly less efficient in supporting the attachment of hGFs and hPDLs (P <0.05). Moreover, the morphologic parameters, including length, area, perimeter, and shape factor, were altered (P <0.001) for cells on both glycated proteins. Finally, cell migration was reduced on glycated FN and COLI (P <0.001). MG treatment efficiently glycated COLI and FN, providing a new tool to study the effects of diabetes on periodontal disease. The substantial effects of glycated COLI and FN on hGF and hPDL behavior indicated that protein glycation contributed to the pathogenesis and altered periodontal wound healing observed in patients with diabetes.

Fibronectin Fragmentation Is a Feature of Periodontal Disease Sites and Diabetic Foot and Leg Wounds and Modifies Cell Behavior

Fibronectin (FN) undergoes fragmentation in periodontal disease sites and in poorly healing diabetic wounds. The biologic effects of FN fragments on wound healing remain unresolved. This study characterized the pattern of FN fragmentation and its effects on cellular behavior compared to intact FN. Polyclonal antibodies were raised against FN and three defined recombinant segments of FN and used to analyze gingival crevicular fluid from periodontal disease sites in systemically healthy subjects and in subjects with diabetes, as well as chronic leg and foot wound exudates from subjects with diabetes. Subsequently, the behavior of human gingival fibroblasts (hGFs) and HT1080 reference cells were analyzed by measuring cell attachment, migration, and chemotaxis in the presence of intact FN or recombinant FN fragments. FN fragmentation was evident in fluids from periodontal disease sites and diabetic leg and foot wounds. However, no fragmentation pattern distinguished systemically healthy subjects from subjects with diabetes. hGFs and HT1080 cells required significantly higher concentrations of FN fragments to achieve attachment comparable to intact FN. Cells cultured on FN fragments also were morphologically different from cells cultured on full-length FN. Migration was reduced for hGFs cultured on FN fragments relative to full-length FN. In contrast, FN fragments increased HT1080 fibrosarcoma cell migration over intact FN. FN fragmentation is a prominent feature of periodontal and chronic leg and foot wounds in diabetes. Furthermore, cell culture assays confirmed the hypothesis that exposure to defined FN fragments significantly alters cell behavior.

Estrogen and Extracellular Matrix Influence Human Gingival Fibroblast Proliferation and Protein Production

A paucity of information exists concerning how estrogen affects cellular function in the gingiva of women. In this study, the behavior of human gingival fibroblasts was examined in the presence of a potent estrogen, estradiol. Quiescent, premenopausal gingival fibroblasts were incubated in the presence and absence of estradiol (1 nM) and/or raloxifene (100 nM). Cell number was determined and cell cycle analyzed using a flow cytometer. Collagen and non-collagen production in cell cultures grown on various extracellular matrices were determined using a radioactive microassay which measures collagenase-digestible and collagenase-resistant radiolabeled proteins. To ascertain if the gingiva contained specific estrogen-sensitive cell populations, a fluorescence-activated cell sorter was used to detect, sort, and enrich fibroblast populations responsive to estrogen. Cellular proliferation and the number of cells entering the S-phase of the cell cycle were significantly increased in mass cultures of fibroblasts stimulated by estradiol. Raloxifene did not antagonize the action of estradiol on cell proliferation. In regard to protein production, estradiol significantly reduced collagen production on plastic and collagen IV matrices; whereas non-collagen protein production on plastic and collagen I matrices was significantly reduced. Cell sorting of mass fibroblast populations revealed that, on average, 45% of the cells from the resident population selectively accumulated the estrogen probe. These sorted and estrogen-sensitive enriched cell populations proliferated in the presence of 1 nM estradiol, whereas the sorted, estrogen-deficient enriched fibroblast populations did not proliferate when incubated with 1 nM estradiol. These data indicate that estradiol can induce cellular proliferation while depressing protein production in cultures of human, premenopausal gingival fibroblasts. This cellular proliferation appears to be the result of a specific population of cells within the parent culture that responds to physiologic concentrations of estradiol.

Effects of TCP/HA-coating titanium on the adhesion behavior of human gingival fibroblasts

To investigate effects of hydroxyapatite (HA) and porous tricalcium phosphate/hydroxyapatite (TCP/HA)-coating titanium on the adhesion behavior of human gingival fibroblasts (HGFs). Coatings of HA and duplex phases TCP/HA on titanium (Ti) were formed by ion beam assisted deposition (IBAD) method. Attachment, spreading, extracellular matrix (ECM) production, and focal adhesion plaque formation of HGFs were investigated on commercially pure (CP) titanium, HA-coated CP titanium and porous TCP/HA-coated CP titanium. After incubation of HGFs on these substrates, the number of attached cell, the area of cell spreading, immunostained ECM including fibronectin (FN) and type I collage, and vinculin (presenting the formation of focal adhesion plaque) were quantified by morphometric analysis using immunofluorescence microscope. TCP/HA and HA coatings exhibited that the attached cell number and cell spreading area were greater than those of CP titanium (P < 0.05), and the formation of focal adhesion plaque was earlier than that of uncoated substrate (P < 0.05). The number of attached cell and the formation of type I collagen on TCP/HA were more than those on Ti and HA. After 24-hour incubation on TCP/HA surface, the number of attached cell was 198.1 +/- 27.7 and the fluorescent intensity of type I collagen was 154.10 +/- 31.56. While under the same condition, the corresponding numbers for the CP titanium were 125.1 +/- 29.9 and 132.63 +/- 35.26. The differences between the two groups were significant (P < 0.05). In this study, the porous TCP/HA coating significantly facilitated the adherence of human gingival fibroblasts to Ti surface and could improve the biocompatibility of titanium.

Chemical modification of metallic implant surfaces with biofunctional proteins (Part 1). Molecular structure and biological activity of a modified NiTi alloy surface.

Human plasma fibronectin (pFN), an adhesive protein, was covalently immobilized onto an alkylaminosilane derivative of a NiTi substrate with glutaraldehyde through Schiff's base formation. The surface at different stages of the modification was characterized by X-ray photoelectron spectroscopy (XPS), and the amount of immobilized pFN was determined by a fluorometric method. The spreading behavior of human gingival fibroblasts was examined on the modified surface. The XPS spectra suggested that gamma-aminopropyltriethoxysilane (gamma-APS) was bonded to the surface through metallosiloxane bonds (Ti-O-Si) formed via a condensation reaction between the silanol end of gamma-APS and the surface hydroxyl group, with a highly cross-linked siloxane network formed after heat treatment of the silanized surface at 100 degrees C. The pFN was immobilized at the surface density of 1.1 micrograms.cm-2, and significantly promoted fibroblast spreading, suggesting that this chemical modification offers an effective means of controlling metal/cell interactions. These results may contribute to the development of bioactive metallic implants.