Gunilla Bratthall

The human periodontal ligament cell: a fibroblast-like cell acting as an immune cell

BACKGROUND Periodontal ligament cells are fibroblast-like cells characterized by collagen production but also possessing some osteoblastic features. In the light of numerous studies presented during recent times, which show that human periodontal ligament cells also produce cytokines and chemokines in response to inflammation promoters, it is reasonable to suggest that periodontal ligament cells play a role as promoters of periodontal inflammation through these mechanisms. MATERIAL AND METHODS The periodontal ligament, which harbours the periodontal ligament cells, is a part of the attachment apparatus comprised of periodontal ligament cells, extracellular matrix and fibres, attaching the root cement to the alveolar bone. Periodontal ligament cells are in close proximity to bacteria within the plaque and the pocket, and thus these cells are readily accessible to bacterial endotoxins and other promoters of inflammation. RESULTS Cytokines and chemokines, released by periodontal ligament cells upon stimulation with inflammation promoters, reach the blood vessels easily thanks to rich vascularization of the periodontium stimulating recruitment of white blood cells to the site of inflammation. In addition to classical inflammatory cells, such as leucocytes, macrophages and mast cells, the periodontal ligament cells also contribute to periodontal inflammation via their production and release of cytokines and chemokines. CONCLUSION Therefore, pharmacological treatment of periodontitis should aim to reduce the release of proinflammatory agents not only from classical inflammatory cells but also from periodontal ligament cells.

LPS-induced MCP-1 and IL-6 production is not reversed by oestrogen in human periodontal ligament cells

OBJECTIVE Periodontal ligament (PDL) cells express oestrogen receptors but the functional importance of oestrogen in PDL cells exposed to bacterial endotoxins is not known. Here we investigate if the inflammation promoter lipopolysaccharide (LPS) affects PDL cell production of interleukin-6 (IL-6), monocyte chemoattractant protein-1 (MCP-1), C-reactive protein (CRP) and/or normal functional PDL cell characteristics such as collagen synthesis and cell proliferation and if oestrogen modulates the effects of LPS. METHODS PDL cells were obtained from periodontal ligament of premolars. PDL cells were treated with Escherichia coli LPS in the absence or presence of oestrogen (17beta-oestradiol, E2). Cellular concentration of IL-6, MCP-1 and CRP was determined by enzyme-linked immunosorbent assay (ELISA). Collagen synthesis was determined by l-[3H]proline incorporation. Cell proliferation was assessed by DNA synthesis measurement using [3H]thymidine incorporation. RESULTS Stimulation with LPS (500 ng/ml to 10 microg/ml) increased IL-6 production in a concentration-dependent manner. Lower concentration (100 ng/ml) of LPS had no effect. LPS-induced stimulation of IL-6 was not reversed by a physiologically high concentration (100 nM) of E2. LPS increased also MCP-1 production which was unaffected by E2. Treatment with E2 alone had no effect on either IL-6 or MCP-1. Stimulation with LPS had no effect on CRP. LPS did not affect collagen synthesis and cell proliferation, reflecting normal physiological properties of PDL cells. CONCLUSIONS LPS stimulates PDL cell IL-6 and MCP-1 production but has no effect on the normal physiological properties of PDL cells. LPS-induced IL-6 and MCP-1 is not reversed by oestrogen suggesting that oestrogen exerts no anti-inflammatory effect via this mechanism.

Immunocytochemical demonstration of estrogen receptor beta in human periodontal ligament cells.

Two transcription associated estrogen receptor (ER) subtypes have been identified and named ERalpha and ERbeta. In the present study we investigate the expression of these ER subtypes in cultured human periodontal ligament (PDL) cells by immunocytochemistry. ERbeta immunoreactivity was observed in the nuclei of about 40% of the PDL cells, while no ERalpha immunoreactivity was detected. In human breast cancer MCF-7 cells, serving as positive controls, both ERalpha and ERbeta immunoreactivities were demonstrated. No immunoreactivity was observed after omission of the primary antibodies. This study suggests that estrogen acts on gene transcription preferentially via ERbeta in human PDL cells.

Differential regulation of chemokine expression by estrogen in human periodontal ligament cells

BACKGROUND AND OBJECTIVE Estrogen modulates inflammatory responses, but the mechanisms involved have not yet been identified. Periodontal ligament (PDL) cells produce chemokines (a group of chemoattractant molecules that recruit leukocytes) and it has been suggested that estrogen modulates periodontal inflammation by regulating the expression of chemokines by PDL cells. Therefore, the objectives of this study were to investigate the regulation of chemokine ligand 2 [CCL2/monocyte chemoattractant protein 1 (MCP-1)], chemokine ligand 3 [CCL3/macrophage inflammatory protein-1α (MIP-1α)] and chemokine ligand 5 (CCL5/RANTES) by estrogen in human PDL cells. MATERIAL AND METHODS PDL cells were obtained from the PDL of premolars, extracted for orthodontic reasons, from two boys and two girls (16 and 17 years of age). PDL cell CCL2, CCL3 and CCL5 mRNA transcripts were determined by quantitative real-time PCR. The concentrations of CCL2, CCL3 and CCL5 proteins were determined by ELISAs. RESULTS Treatment with 0.5 μg/mL of lipopolysaccharide (LPS, from Escherichia coli) + 100 nm 17β-estradiol (E(2) ) for 24 h reduced the expression of CCL3 mRNA by about 40% compared to PDL cells treated with LPS alone. Attenuation of CCL3 mRNA was not associated with a decrease in CCL3 protein within 48 h, suggesting a slow turnover of the CCL3 protein. Interindividual differences in the effects of E(2) on CCL5 mRNA expression were observed. E(2) (100 nm) increased the expression of CCL5 by 40-60% in PDL cells derived from two subjects but reduced the expression of CCL5 by about 30% in cells from another subject. CCL2 mRNA and CCL2 protein were highly expressed, but not regulated by E(2) . Similar data were observed in cells obtained from both boys and girls. CONCLUSION Regulation, by estrogen, of chemokine expression in PDL cells shows a complex pattern involving the down-regulation as well as the up-regulation of chemokines, suggesting that estrogen exerts both anti-inflammatory and proinflammatory effects through these mechanisms.

Estrogen regulates DNA synthesis in human gingival epithelial cells displaying strong estrogen receptor β immunoreactivity.

BACKGROUND AND OBJECTIVE Estrogen acts via estrogen receptor (ER) α and β. The expression pattern of ERs and their importance in gingival tissues are not fully understood. In this study, we investigate gingival ER expression and effects of estrogen on gingival epithelial cell proliferation. MATERIAL AND METHODS Gingival biopsies were obtained from both healthy and diseased sites in three male and three female subjects. Expression of ERα and β was determined by immunohistochemistry. Effects of 17β-estradiol (E(2) ) on cell proliferation, monitored by measuring DNA synthesis, were studied in cultured human gingival epithelial HGEPp.05 cells. RESULTS Estrogen receptor β, but not ERα, immunoreactivity was demonstrated in nuclei of epithelial cells in all layers of the gingival epithelium, but also in cells of the lamina propria. No differences were observed between male and female subjects. The same pattern, i.e. high ERβ expression but no ERα expression, was observed in both healthy and diseased sites within each individual. No differences in the intensity of the ERβ immunoreactive signal and the number of ERβ-positive nuclei were observed between healthy and diseased gingiva. Treatment with a physiological concentration of E(2) (10 nm) had no effect on DNA synthesis in ERβ- and ERα-expressing HGEPp.05 cells. In contrast, E(2) at high concentrations (500 nm and 10 μm) reduced DNA synthesis by 60-70%. CONCLUSION Human gingival epithelial cells display strong ERβ but low ERα immunoreactivity both in vivo and in culture. Estrogen attenuates gingival epithelial cell DNA synthesis at high but not low concentrations, suggesting a concentration-dependent mechanism.

Effects of ovariectomy and aging on tooth attachment in female mice assessed by morphometric analysis.

Objective. Non-human primates, dogs, rats, hamsters and ferrets, have frequently been used as laboratory animals in periodontal biology and pathology. In the past, mice have been used less for this purpose, but nowadays attract a lot of interest because gene knockout and transgenic technologies utilize mice primarily. In this study, we investigate the effects of ovariectomy and aging on tooth attachment in female mice. Material and methods. Eight-week-old mice (n=15) were divided into three experimental groups (control, n=5; sham-operated, n=5; ovariectomy, n=5) and ovaries removed bilaterally. Attachment level, assessed by measuring alveolar bone height and apical termination of the junctional epithelium, was determined 6 weeks post-ovariectomy by digital morphometric analysis in sagittal sections of the mandible. The plasma level of the inflammation marker serum amyloid A (SAA) was determined by ELISA. In another series of experiments, tooth attachment was determined in female mice (n=7) at 8–26 weeks of age. Results. Withdrawal of female sex hormone production by ovariectomy had no effect on alveolar bone height and apical termination of the junctional epithelium. The SAA level in plasma was unaffected by removal of the ovaries, suggesting that systemic inflammation is not induced by ovariectomy. Bone height was similar in mice sacrificed at 8–26 weeks of age and apical termination of the junctional epithelium was at the cemento-enamel junction at all ages. Conclusions. Removal of ovarian production of female sex hormones by ovariectomy has no influence on tooth attachment, and further tooth attachment is preserved with age in female mice.

Alpha-1-antitrypsin deficiency and periodontitis, a pilot study

Background: The significance of access to dental care on oral conditions in older subjects is limited. We hypothesized that dental care control for aging effects on oral and periodontal conditions. Materials and methods: 1020 randomly selected subjects between age 60 and 96 from the Swedish National Study on Aging and Care Blekinge study received comprehensive medical and dental examinations. Results: Dentate women and men had, on average,18.4 teeth (S.D. ± 7.6), and 18.9 teeth (S.D.±7.5) (P = 0.37) respectively. In the youngest age group with infrequent dental visits 37% had > 20 teeth, and 73% had > 20 teeth if they had annual visits. Among old-old infrequent dental visitors 1.8% had > 20 teeth and 37% had > 20 teeth with annual visits. Across age groups, the overall % bleeding on probing was 23%. When adjusting for age, GLM univariate analysis failed to demonstrate an effect of frequency of dental visits and ABL scores (P = 0.18) but frequent dental visitors had significantly more teeth than infrequent visitors (P = 0.001). Conclusions: Tooth loss and extent of alveolar bone loss increase with age. Frequent dental visits seem to preserve teeth but has no impact on the amounts of deposits, gingival inflammation, or alveolar bone levels.This free journal suppl. entitled: Special Issue: Abstracts of Europerio 6, 4-6 June 2009, Stockholm, SwedenBackground: The periodontal ligament cells (PDL cells) play a key role in the formation of the periodontal ligament but these cells have other functions as well. The PDL cells express estrogen rec ...

Estrogen affects gene expression in LPS stimulated PDL-cells

Background: The significance of access to dental care on oral conditions in older subjects is limited. We hypothesized that dental care control for aging effects on oral and periodontal conditions. Materials and methods: 1020 randomly selected subjects between age 60 and 96 from the Swedish National Study on Aging and Care Blekinge study received comprehensive medical and dental examinations. Results: Dentate women and men had, on average,18.4 teeth (S.D. ± 7.6), and 18.9 teeth (S.D.±7.5) (P = 0.37) respectively. In the youngest age group with infrequent dental visits 37% had > 20 teeth, and 73% had > 20 teeth if they had annual visits. Among old-old infrequent dental visitors 1.8% had > 20 teeth and 37% had > 20 teeth with annual visits. Across age groups, the overall % bleeding on probing was 23%. When adjusting for age, GLM univariate analysis failed to demonstrate an effect of frequency of dental visits and ABL scores (P = 0.18) but frequent dental visitors had significantly more teeth than infrequent visitors (P = 0.001). Conclusions: Tooth loss and extent of alveolar bone loss increase with age. Frequent dental visits seem to preserve teeth but has no impact on the amounts of deposits, gingival inflammation, or alveolar bone levels.This free journal suppl. entitled: Special Issue: Abstracts of Europerio 6, 4-6 June 2009, Stockholm, SwedenBackground: The periodontal ligament cells (PDL cells) play a key role in the formation of the periodontal ligament but these cells have other functions as well. The PDL cells express estrogen rec ...

Functional significance of female sex hormone rece

The similarity of periodontitis and peri-implantitis demands for the utilization of similar principles for the treatment. Different decontamination methods were available cleaning of implant surfaces contaminated with bacteria. The aim of the present study was to evaluate the effects of various decontamination methods on reosseointegration on contaminated implants. Six mongrel dogs were used. The mandibular 1st molars and all premolars were removed bilaterally. Three months later, experi- mental implants with different surface characters were installed in each sides of the mandible. The implant consisted of two parts; the implant body and an exchangeable intraosseous implant cylinder. After osseointegration, experimental peri-implantitis was induced by cotton ligatures until the bone loss reached the junction of the two segments of the implant. After debridement of the bone defects, three treatment models were performed; (i) contaminated cylinders were removed, pristine cylinders were placed; (ii) contaminated cylinders were cleaned in situ with saline and (iii) contaminated cylinders was removed, cleaned with saline, sterilized by autoclaving. All implants were covered with membranes. After 3 months, histological evaluations were accomplished. The results indicated that in situ saline therapy demonstrated a significant difference at SLA surfaces in bone-implant-contact. Treatment of contaminated implants in situ with saline resulted in resolution of peri-implantitis and bone fill in defects.