Anti-inflammatory effect of a fatty acid mixture with high ω-9:ω-6 ratio and low ω-6:ω-3 ratio on rats submitted to dental extraction

ObjectiveTo evaluate the anti-inflammatory effect of pretreatment for three days with a fatty acid mixture with high ω-9:ω-6 ratio and low ω-6:ω-3 ratio on rats submitted to dental extraction.Material and methodsThirty-two male Wistar rats (270–310 g) were randomly distributed in four groups (n = 8/group): the sham control group and the negative control group received saline; the high omega-6/low omega-9 group received isolipid fatty acid with high ω-6:ω-3 ratio and low ω-9:ω-6 ratio; the high omega-3/low omega-6 group received fatty acid with low ω-6:ω-3 ratio and high ω-9:ω-6 ratio. Saline and oils were administered by gavage for 4 days before exodontia and 3 days after surgery, followed by euthanasia. Masseter edema was evaluated clinically and tissue samples were submitted to osteoclast count (H&E), myeloperoxidase assay, and western blotting (tumor necrosis factor-alpha and interleukin-1beta).ResultsIn the high omega-3/low omega-6 group, a significant decrease was observed in masseter edema (p < 0.0001), myeloperoxidase (p < 0.0001), osteoclasts (p = 0.0001) and TNF-α expression (p < 0.0001), but not in IL-1β expression.ConclusionThe ingestion of fatty acid with high ω-9:ω-6 ratio and low ω-6:ω-3 ratio significantly reduced inflammatory response in rats submitted to dental extraction.     

Genetic and immunological markers predict titanium implant failure: a retrospective study

This study evaluates diagnostic markers to predict titanium implant failure. Retrospectively, implant outcome was scored in 109 subjects who had undergone titanium implant surgery, IL1A ?889 C/T (rs1800587), IL1B +3954 C/T (rs1143634), IL1RN +2018 T/C (rs419598) and TNFA ?308 G/A (rs1800629) genotyping, in vitro IL-1β/TNF-α release assays and lymphocyte transformation tests during treatment. TNF-α and IL-1β release on titanium stimulation were significantly higher among patients with implant loss (TNF-α: 256.89 pg/ml vs. 81.4 pg/ml; p < 0.0001; IL-1β: 159.96 pg/ml vs. 54.01 pg/ml; p < 0.0001). The minor alleles of the studied polymorphisms showed increased prevalence in the implant failure group (IL1A: 61% vs. 42.6% in controls, IL1B: 53.7% vs. 39.7% in controls, TNFA: 46.3% vs. 30.9% in controls, IL1RN: 58.5% vs. 52.9% in controls). Increasing numbers of risk genotypes of the studied polymorphisms were associated with an increasing risk of implant loss, suggesting an additive effect. Multiple logistic regression analysis showed positive IL-1β/TNF-α release assay scores (p < 0.0001, OR = 12.01) and number of risk genotypes (p < 0.046, OR = 1.57–6.01) being significantly and independently associated with titanium implant failure. IL-1/IL1RN/TNFA genotyping and cytokine release assay scores provide prognostic markers for titanium implant outcome and may present new tools for individual risk assessment.     

The action of anti-inflammatory agents in healthy temporomandibular joint synovial tissues is sex-dependent

This study evaluated the effects of dexamethasone, parecoxib, and glucosamine on cartilage thickness and cytokine levels in the temporomandibular joint (TMJ). Forty-eight rats (24 female, 24 male) were assigned to four treatments administered once daily for 7 days: control (saline intramuscularly), parecoxib (0.3 mg/kg intramuscularly), dexamethasone (0.1 mg/kg intramuscularly), and glucosamine (80 mg/kg orally). The thickness of TMJ cartilage and levels of four cytokines were measured. Median cartilage thickness was higher in males than in females in the control (253.2 vs. 240.4 μm, P = 0.0036), parecoxib (227.3 vs. 192.1 μm, P < 0.0001), and dexamethasone (227.1 vs. 170.5 μm, P = 0.017) groups, but was lower in males in the glucosamine group (214.5 vs. 239.6 μm, P = 0.0001). IL-1β was not detected. Median IL-1α levels differed between males and females in the parecoxib group (0.08 vs. 0.04 ng/ml, P = 0.0055), but not in the control (0.07 vs. 0.06 ng/ml), dexamethasone (0.06 vs. 0.04 ng/ml), or glucosamine (0.08 ng/ml vs. 0.06 ng/ml) groups (all P > 0.05). Only dexamethasone induced lower IL-6 levels in males than in females (median 4.6 vs. 2.1 ng/ml, P = 0.0044). Median TNF-α levels did not differ between males and females in the control (0.07 vs. 0.05 ng/ml) or parecoxib (0.07 vs. 0.05 ng/ml) groups (both P > 0.05), but dexamethasone (0.09 vs. 0.05 ng/ml, P = 0.0002) and glucosamine (0.09 vs. 0.07 ng/ml, P = 0.0259) induced higher TNF-α levels in females. Thus, the effects of the three treatments on the levels of cytokines and thickness of condylar cartilage were sex-dependent.     

Irrigation fluid volume requirement for conventional arthrocentesis of the temporomandibular joint: a cadaver study

Temporomandibular joint (TMJ) arthrocentesis is considered an effective and minimally invasive procedure for certain conditions related to temporomandibular disorders. The ideal irrigation volume for arthrocentesis lavage has not yet been defined. Therefore, the aim of this study was to evaluate the efficacy of different saline solution volumes in removing methylene blue from the TMJ space of fresh human cadavers. Nineteen cadavers were selected and 1 ml of 10 μM methylene blue solution was injected into the upper joint space unilaterally. Conventional arthrocentesis was then conducted by infusion of 300 ml of 0.9% saline solution, collecting a 1-ml sample from the drained quantity for every 25 ml injected. Finally, the samples were assayed by measuring photo absorbance of the methylene blue solution. There was a statistically significant difference between the irrigation volumes regarding the removal of methylene blue solution from the joint space (P < 0.001), specifically between the first 25 ml and 200 ml (P = 0.014), 225 ml (P = 0.001), 250 ml (P < 0.001), and 275 ml (P = 0.001). Based on this ex vivo study, a 25-ml perfusion volume appears to be sufficient for joint lavage in conventional arthrocentesis of the TMJ.     

Comparison of the outcomes of three surgical treatments for end-stage temporomandibular joint disease

The aim of this study was to determine whether there are any differences between condylectomy, rib grafts, and prosthetic joints (Biomet TMJ stock prosthesis) with regard to outcomes for patients with end-stage temporomandibular joint (TMJ) disease. Fifty-six of a total 127 patients who presented with category 5 end-stage TMJ disease over 3 years (2010–2013) agreed to participate in this retrospective, comparative, cohort study. Patients were divided into four groups: preoperative (n = 16), condylectomy (n = 8), rib graft (n = 16), and prosthetic joint (n = 16). They were assessed for major postoperative complications (i.e., return to theatre) and maximum range of mandibular motion, and all completed a specific quality of life (QOL) questionnaire. Whilst the condylectomy group demonstrated the best mandibular range of motion (P < 0.01), rib graft patients were more likely to experience complications (43.8%) necessitating a return to theatre. The prosthesis group recorded the best mean aggregate QOL score, but the difference compared to the rib graft and condylectomy groups was not statistically significant. The results of this study suggest that for dentate patients, prosthetic joints are highly dependable with no returns to theatre and favourable QOL outcomes. For edentulous patients, condylectomies alone also appear to work well. Future TMJ prosthetic designs should focus on improving mandibular range of motion, as the current stock prosthesis allows only a restricted range, no better than that achieved with rib graft (P > 0.05) and far less than that achieved with condylectomy (P < 0.01).     

Effects of autogenous growth factors on heterotopic bone formation of osteogenic cells in small animal model

AimsThis study used a new approach to investigate the effective concentrations of growth factors released from platelet concentrate (PC) on the bone formation capacity of osteogenically differentiated rat bone marrow stromal cells (rBMSCs).Materials and methodsRat BMSCs and whole blood were harvested from 40 adult male Spraque-Dawly rats. Rat BMSCs were expanded in an osteogenic medium and seeded on inert collagenous bovine bone matrix (ICBM). Growth factors released from degranulated PC (GFs) containing TGF-β1 1 (25 ng/ml)–10 ng (250 ng/ml) and rhBMP-2 400 ng (10 μg/ml) were suspended in 40 μl platelet poor plasma (PPP) and applied on the ICBM–rBMSC constructs or ICBM only, respectively. The constructs were then transplanted in autologous hosts for 4 weeks. Concurrently, osteoblastic differentiation of rBMSCs on ICBM–rBMSC–PPP constructs was characterized in vitro.ResultsRat BMSCs in osteogenic medium exhibited phenotypes of mature osteoblasts. The amount of newly formed bone among groups of ICBM–rBMSC–PPP with and without GFs was not significantly different (p > 0.05) and was significantly lower than a group of ICBM–PPP–BMP-2 (p < 0.05).ConclusionsAutogenous GFs had no effect on the capacity of rBMSCs to form new bone. The ability to measure the bone formation capacity of transplanted autologous cells and growth factors in a small animal model was demonstrated.     

Effects of connective tissue growth factor on human periodontal ligament fibroblasts

ObjectiveThe aim of this study was to evaluate the effects of different concentrations of connective tissue growth factor (CTGF) on human periodontal ligament fibroblasts(HPLFs).DesignHPLFs were cultured and identified. Then, different concentrations of CTGF (1, 5, 10, 50, 100 ng/ml) were added to the HPLF culture. Next, CCK-8 assays, alkaline phosphatase (ALP) assays, hydroxyproline determination, alizarin red staining methods, Transwell chambers and real-time PCR methods were applied to observe the effects of CTGF on the proliferation, ALP activity, synthesis of collagen, formation of mineralized nodules and migration. We also studied expression of ALP, fiber link protein (FN), integrin-binding sialoprotein (IBSP), osteocalcin (OC), and integrin beta 1 (ITGB1) mRNA by HPLFs. Statistical significance was assumed if P < 0.05 or P < 0.01.ResultsThe addition of CTGF (1, 5, 10 ng/ml) remarkably promoted the proliferation and collagen synthesis of HPLFs compared with controls. CTGF (1, 5, 10, 50 ng/ml) improved ALP activity of HPLFs, and at all concentrations, CTGF (1, 5, 10, 50, 100 ng/ml) improved the expression of ALP, FN, IBSP and ITGB1 mRNA. In addition, CTGF (1, 5, 10, 50, 100 ng/ml) promoted the migration of HPLFs, which was dose-dependent, with maximal promotion in the 10 ng/ml group (P < 0.05 or P < 0.01).ConclusionsThus, in a certain range of concentrations, CTGF can promote the biological effects, including proliferation, migration and collagen synthesis of HPLFs, to promote the differentiation of HPLFs in the process of osteogenesis.     

Effectiveness of treatment with viscosupplementation in temporomandibular joints with or without effusion

The objective of this study was to determine whether the effectiveness of viscosupplementation with hyaluronic acid (HA) in patients with temporomandibular joint (TMJ) degenerative disorders depends on the presence of intra-articular effusion. In this study of case–control design, two groups of 25 patients were recruited: patients with a clinical diagnosis of painful chronic TMJ osteoarthritis and magnetic resonance imaging (MRI) signs of TMJ degeneration, with (effusion group) or without (no effusion group) MRI evidence of TMJ effusion. All patients underwent five weekly single-needle arthrocenteses plus medium molecular weight HA and 6 months of follow-up. Several clinical outcome parameters were assessed. For all variables, analysis of variance (ANOVA) for repeated measures was performed to assess the existence of significant within-group and between-group treatment effects. Over time, both groups showed significant improvements in all outcome parameters, which were maintained at the 6-month follow-up (P < 0.05). Between-group comparisons showed that the treatment effects did not differ significantly for either the primary outcome variable (pain levels: F = 0.849, P = 0.548) or secondary outcome variables (chewing efficiency: F = 0.854, P = 0.544; functional limitation: F = 1.35, P = 0.226; mouth opening: F = 0.658, P = 0.707). The null hypothesis that there are no differences in treatment effectiveness between patients with and without effusion could not be rejected.     

Treatment modalities of TMJ ankylosis: experience in Delta Nile,Egypt

The study reports the authors’ experience in managing TMJ ankylosis in Delta Nile, Egypt (1995–2006) and compares the surgical modalities used. 101 patients (109 joints) were reviewed in this retrospective study. Pre- and postoperative assessment included history, radiological and physical examination, and mouth opening. Age, sex, aetiology, joint(s) affected, surgical modality, complications and follow up periods were evaluated. Various types (fibrous, fibro-osseous and bony) of TMJ ankylosis were diagnosed; trauma was the commonest aetiology. The patients’ age range was 2–41 years, 62% were female, and the follow up period ranged from 14 to 96 months. Average mouth opening was significantly increased from 5.3 mm pre-operatively to 32.9 mm 12 months postoperatively (P = 0.0001). Marked improvement in mouth opening was documented when the ramus-joint complex was reconstructed using distraction osteogenesis (34.7 mm), costochondral graft (34.4 mm) and Surgibone (34.6 mm). Gap arthroplasty showed least satisfactory mouth opening compared with other techniques (P = 0.001). Minor and major complications were encountered in 33% of cases, including 5% recurrence rate. Early release of TMJ ankylosis; reconstruction of the ramus height with distraction osteogenesis or bone grafting combined with interpositional arthroplasty, followed by vigorous physiotherapy is successful for managing TMJ ankylosis.     

Evaluation of the gingival inflammation in pregnancy and postpartum via 25-hydroxy-vitamin D3, prostaglandin E2 and TNF-α levels in saliva

BackgroundPhysiological changes and immunological modifications occur during pregnancy. The clinical and biological features of periodontal infections are affected by pregnancy. The aim of the present study was to evaluate saliva levels of 25-hydroxy-vitamin D3 (25(OH)D3), prostaglandin E2 (PGE₂) and TNF-alpha (TNF-α) in pregnancy, postpartum and non-pregnant controls.MethodsWhole saliva samples together with full-mouth clinical periodontal recordings were obtained from 59 pregnant, 47 post partum and 70 systemically healthy non-pregnant women. Groups were also evaluated according to the periodontal health status. 25(OH)D3, PGE₂ and TNF-α levels in the saliva samples were determined by enzyme-linked immunoassays. Data were statistically tested by nonparametrical tests.ResultsSaliva TNF-α and PGE₂ levels were significantly lower and 25(OH)D3 levels were significantly higher in the pregnant group than postpartum group (p < 0.0001). Saliva TNF-α and 25(OH)D3 levels were significantly higher and PGE₂ levels were significantly lower in the control group than postpartum group (p < 0.0001). In the pregnant healthy, gingivitis and periodontitis groups saliva TNF-α levels were significantly lower than postpartum and control counterparts (p < 0.0001, p = 0.032, p = 0.003 and p = 0.013; p = 0.027; p = 0.007, respectively). In control healthy, gingivitis and periodontitis groups saliva 25(OH)D3 levels were significantly higher than the postpartum counterparts (p < 0.0001, p < 0.0001, p = 0.002, respectively). In the control healthy and gingivitis groups saliva 25(OH)D3 levels were significantly higher than pregnant healthy and gingivitis (p < 0.0001).ConclusionsIn conclusion, within the limits of the present study it seems that pregnancy have an effect on parameters in saliva in relation to the periodontal status of the women. Further studies are required for better understanding of the impact of periodontal diseases on pregnancy or otherwise.     

Effect of glucosamine sulphate on the temporomandibular joint of ovariectomised rats

Glycosamine is an amino-monosaccharide present in connective and cartilage tissues that contribute to the maintenance, resistance, flexibility, and elasticity of these tissues. This study aimed to determine the in vivo effects of glucosamine sulphate (GS) on the temporomandibular joint (TMJ) of ovariectomised rats (OVX).Thirty-two rats were distributed into four groups as follows: G1, sham-OVX + saline solution; G2, sham-OVX + glucosamine sulphate (80 mg/kg) – oral administration; G3, OVX + saline solution; G4, OVX + glucosamine sulphate (80 mg/kg) – oral administration. Animals were treated for seven days. The TMJ was removed and stained with toluidine blue. The thickness of the cartilage layers and cytokines IL-1β, IL-6, and TNF-α levels were determined by histomorphometry and immunoassay, respectively. The administration of GS to OVX females did not change the thickness of condylar cartilage when compared with the other groups (p > 0.05). There was an increase in the total cartilage thickness in sham-OVX females. IL-1β and TNF-α levels were significantly lower in sham-OVX females than in OVX females, indicating that ovariectomy acts as potent cytokine inducer. IL-6 levels were significantly higher in sham-OVX females. GS did not affect cytokine production in OVX females (p > 0.05). In conclusion, the administration of GS did not affect cytokine levels, but did induce an increase in the total thickness of the TMJ condylar cartilage in sham-OVX rats.     

Temporomandibular joint replacement: a New Zealand perspective

Alloplastic total temporomandibular joint replacement (TMJ TJR) has been performed in New Zealand utilizing the TMJ Concepts patient-fitted system since 2000. The data analysed in this study were collected retrospectively from questionnaires sent to all maxillofacial surgeons in New Zealand who had implanted TMJ Concepts devices between 2000 and 2011. A total of 63 devices were implanted in 42 patients (13 males, 29 females) during this 12-year period. The primary indication for TMJ TJR was end-stage joint disease resulting from ankylosis and arthritis. The mean age of the patients was 47 years (range 7–80 years). The most common complication reported was transient facial nerve impairment in 4.8% of the patients. Objective results, measured as the maximal incisional opening, improved by a mean of 17.3 mm (P < 0.01); 90% of patients reported improved quality of life. New Zealand oral and maxillofacial surgeons have concluded that TMJ TJR using the TMJ Concepts prosthesis is a reliable treatment option for the management of end-stage TMJ disease.     

A cohort study of patients with juvenile idiopathic arthritis and arthritis of the temporomandibular joint: outcome of arthrocentesis with and without the use of steroids

The purpose of this study was to evaluate the effects of intra-articular temporomandibular joint (TMJ) treatment in patients with juvenile idiopathic arthritis (JIA). The inclusion criteria were met by 21 patients (38 joints). Joints were randomly selected for either arthrocentesis alone (n = 17) or arthrocentesis with the additional use of triamcinolone hexacetonide (n = 21) using a closed single-needle system. Measurements of pain and function were performed at baseline and at follow-up after 3 and 8 months. Pain on opening and lateral excursion improved significantly after injections. Pain decreased significantly from baseline to first and second control on a visual analogue scale (VAS) for overall pain (49–18–8) and overall function (41–19–4). Significant improvement was recorded for pain on palpation of muscles and joints. There was no statistically significant difference between the treatment modalities, with or without glucocorticoid injection. Arthrocentesis in the TMJ treatment of patients with JIA may be beneficial and steroids had no additional effect. Further studies are needed to evaluate the long-term effects on the TMJ structures and on condylar growth from arthrocentesis and intra-articular steroid injections.     

Neurosensory assessment in patients with total reconstruction of the temporomandibular joint

Somatosensory sensitivity and postoperative endogenous pain modulation have not been investigated in temporomandibular joint (TMJ) prosthesis patients. The objectives of this study were to assess somatosensory function at the TMJ and examine possible differences in conditioned pain modulation (CPM) between patients with total TMJ prostheses (n = 7) and a reference group of healthy controls (n = 20). Somatosensory abnormalities were assessed using quantitative sensory testing (QST), which encompasses thermal and mechanical testing procedures. CPM was tested by comparing pressure pain thresholds (PPT) before (baseline), during, and after the application of painful and non-painful cold stimuli. PPTs were measured at the TMJ and thenar eminence (control). The effect of CPM on PPT values was tested with analysis of variance. Three patients exhibited mixed somatosensory loss (i.e., decreased thermal and mechanical detection) with mixed hyperalgesia (i.e., increased sensitivity to thermal and mechanical pain) and two patients exhibited mixed loss with only mechanical hyperalgesia. There was a significant decrease in pressure pain sensitivity at both sites during painful cold application in healthy controls (P < 0.001) but not in patients (P = 0.476). In conclusion, QST measures demonstrated somatosensory abnormalities in patients with total TMJ prostheses. Noxious conditioning cold stimuli evoked CPM-like effects in healthy subjects but not in patients with TMJ reconstruction.     

Clinical periodontal status and inflammatory cytokines in gestational diabetes mellitus

ObjectivesThe aim of the present cross-sectional study was to compare clinical periodontal findings as well as gingival crevicular fluid (GCF) and serum levels of tumour necrosis factor-alpha (TNF-α), interleukin-10 (IL-10), and IL-33 between women with and without gestational diabetes mellitus (GDM).MethodsSerum and GCF samples were collected, full-mouth recordings comprising plaque index, bleeding on probing and probing depth were performed in 96 females with GDM (cases) and 65 non-diabetic pregnant females (controls). Age, smoking status, pre-pregnancy body mass index, pregnancy outcomes were recorded. Serum and GCF IL-10, IL-33, TNF-α levels were determined.ResultsThe GDM group was significantly older than the control group with an age difference of 3.27 years (mean ages were 32.05 and 28.78 years, respectively) (p < 0.0001). Plaque Index (50.0 and 30.0 p = 0.005), bleeding on probing (50.0 and 30.0 p = 0.003) values were significantly higher in the GDM group. Serum TNF-α concentrations were significantly higher in the nonGDM group than the GDM group (p = 0.001). GCF IL-10 concentrations and total amounts were significantly higher in the GDM group than the controls (p = 0.004 and p < 0.0001, respectively).ConclusionElevated GCF IL-10 levels may be a consequence of higher levels of inflammation as indicated by higher PI and BOP in the GDM group. However, the investigated clinical parameters may not have prominent effects on TNF-α and IL-33 levels. These findings provide further support for the importance of periodontal health during pregnancy.     

Sinuleptolide inhibits proliferation of oral cancer Ca9-22 cells involving apoptosis,oxidative stress,and DNA damage

ObjectiveSinuleptolide, a soft corals-derived bioactive norditerpenoid, is a marine natural product with a potent anti-inflammatory effect. We evaluate the potential anti-oral cancer effects of sinuleptolide and investigate the possible mechanisms involved.DesignsCell viability, cell cycle, apoptosis, reactive oxygen species (ROS), mitochondrial membrane potential (MMP), and DNA damage analyses were performed.ResultsIn a cell viability assay, we found that sinuleptolide is dose-responsively antiproliferative against oral gingival cancer Ca9-22 cells but less harmful to normal human gingival fibroblast (HGF-1) cells (P < 0.001). In cell cycle analysis, sinuleptolide induced subG1 accumulation at a higher dose and led to G2/M arrest of Ca9-22 cells (P < 0.005). Apoptosis was significantly increased in sinuleptolide-treated Ca9-22 cells based on annexin V and poly(ADP-ribose) polymerase (PARP) expressions (P < 0.05–0.0001). Based on flow cytometer analysis, sinuleptolide also induced the generation of ROS and decreased MMP in a dose-responsive manner (P < 0.05–0.0001). DNA damage increased dose-responsively after sinuleptolide treatments (P < 0.001) based on comet and γH2AX assays.ConclusionSinuleptolide can induce an antiproliferation of oral cancer Ca9-22 cells involving apoptosis, oxidative stress and DNA damage, suggesting that sinuleptolide represents a potential chemotherapeutic drug for oral cancer treatment.     

Possible implications of Ni(II) on oral IL-1β-induced inflammatory processes

ObjectivesNickel (Ni) is one of the main metal elements in orthodontic and prosthetic devices. Different effects of Ni are described ranging from an induction of local inflammation to allergy and cancerous/mutagenic properties. Inflammatory reactions are frequently observed in the oral cavity, but the interrelationship of Ni with those events is still unknown. Therefore, we focused on the impact of Ni on inflammation in vitro.MethodsIn accordance to previous immersion tests of our lab, human gingival fibroblasts (HGFs) (n = 6) were exposed to a pro-inflammatory environment using interleukin-1 beta (IL-1β) and additionally stimulated with different Ni(II) concentrations (400 and 4000 ng/ml). At varying time points the expression of pro- and anti-inflammatory as well as matrix degeneration proteins, i.e. MMPs, were analyzed. Furthermore, proliferation assays, wound healing tests and the detection of NF-κB activation were conducted. Unstimulated HGFs served as control.ResultsOur experiments showed that low clinical average Ni(II) levels did not alter pro-inflammatory cytokines significantly compared to control (p > 0.05). Instead, a 10-fold higher dose up-regulated these mediators significantly in a time-dependent manner (p < 0.01). This was even more pronounced combining both Ni(II) concentrations with an inflammatory condition (p < 0.001), MMP expressions were in line with our findings (p < 0.001). The mRNA data were supported by proliferation and wound closure assays (p < 0.001). However, the combination of both stimuli induced contradictory results. Analyzing NF-κB activation revealed that our results may be in part attributed to NF-κB.SignificanceOur in vitro study implicated that Ni(II) has various modifying effects on IL-1β-induced inflammatory processes depending on the concentration.     

Effects of prostaglandin E2 on clonogenicity,proliferation and expression of pluripotent markers in human periodontal ligament cells

Background and objectiveBased on our earlier work on the response of periodontal ligament (PDL) cells to mechanical stress by induction of cyclooxygenase expression and production of prostaglandin PGE₂ that could regulate mineralization of PDL cells, it was hypothesized that PGE₂ had potential effects on PDL stemness. In this study, we aimed to investigate clonogenicity, proliferation and expression of certain pluripotent markers, considered to be characteristics of PDL stemness, in response to treatment with exogenously-added PGE₂.Material and methodsHuman PDL cells were cultured and treated with various doses of PGE₂, and the aforementioned characteristics of PDL stemness were analyzed.ResultsThe clonogenicity and proliferation were significantly enhanced by PGE₂ at low concentrations (0.01, 0.1 and 1 ng/ml; P < 0.05), but only the proliferation was significantly diminished by PGE₂ at a high concentration (100 ng/ml; P < 0.05). Expression of NANOG and OCT4 mRNA and protein was increased by PGE₂ treatment at 0.1 and 1 ng/ml. Consistently, expression of stage-specific embryonic antigen 4, a putative stem cell marker, was significantly augmented by PGE₂ treatment at 1 ng/ml (P < 0.05).ConclusionOur findings suggest that although a high dose of PGE₂ (100 ng/ml) inhibits proliferation of PDL cells, PGE₂ at low doses appears to play a role in the maintenance of PDL stemness.