Nanodesigned coatings obtained by plasma electrolytic oxidation of titanium implant and their cytotoxicity

The titanium implant was treated with plasma electrolytic oxidation and subsequent ionic exchange and thermal treatment in order to obtain bioactive layer consisting of titanium oxide, calcium and sodium titanates and hydroxyapatite, as confirmed by X-ray diffraction (XRD). Scanning electron microscopy (SEM) revealed that the given method, besides corresponding phase composition, enables suitable nanotopology for cell attachment and proliferation. Cytotoxicity investigations by MTT, LDH and propidium iodide assays and light microscopy showed that these coatings were not toxic to L929 cells.

Nanostructured endodontic materials mixed with different radiocontrast agents-biocompatibility study

The aim of this study was to investigate the biocompatibility of nanostructured materials based on highly active calcium silicates mixed with different radiocontrast agents in comparison to MTA⁺ using in vitro and in vivo model. Morphology of materials' samples was analyzed using SEM while the phase compositions were identified by XRD. pH values of materials' suspensions were conducted by pH-meter. The cytotoxicity of materials' solutions was tested by MTT test (100, 50, 25 and 12.5 mg/ml). LDH and ³H-thymidine assay were utilized for biocompatibility investigations of materials' eluates (24 h, 7 day and 21 day). Eighteen Guinea pigs were used for intramuscular implantation, as teflon tubes with freshly prepared materials were placed into intramuscular pockets. All samples were composed of round and needle-like particles equally distributed with Ca/Si ratio ~2.7 at%, with the presence of hydrated calcium silicate phases. The pH values of ALBO-MPCA₁ and ALBO-MPCA₂ were high alkaline, while in case of MTA⁺ they were lower and continuously declined (p < 0.05). Investigated materials didn't exhibit dose-dependent effect on metabolic activity of L929 cells (p > 0.05). Significant differences in the percentage of cytotoxicity between diluted and undiluted extracts between all tested materials after 24 h and 7 day were noticed (p < 0.05). Increase in L929 cells proliferation was noticed in case of undiluted eluates of ALBO-MPCA₁ and ALBO-MPCA₂ after 7 day (p < 0.05). There were no statistically significant differences in the intensity of inflammatory response between investigated materials and control group after 60 day (p > 0.05). Evaluation of biocompatibility of both ALBO-MPCA₁ and ALBO-MPCA₂ indicate their potential clinical use.

In vitro biocompatibility of nanostructured endodontic materials using SCAP cells

Background/Aim: Lately, fully innovative sol-gel method with high-temperature self-propagating reaction was used for the synthesis of new nanostructured endodontic materials, in combination with different radiopacifiers: bismuth (ALBO-MPCA1) and barium (ALBO-MPCA2). The aim of this study was to investigate the biocompatibility of nanostructured endodontic materials based on highly active calcium silicates and mixed with different radiopacifiers in comparison to MTA+ using human stem cells from the apical papilla- SCAP cells. Material and Methods: Morphology of the samples was studied by SEM. The tested materials were mixed with distilled water in a ratio 2:1 (m/m). Fifteen minutes after the preparation, samples were used in the experiment. The biocompatibility of fresh materials, after 3h and 7 days, was tested using 3-(4,5-dimethylthiazol-2-yl)-2,5- diphenyltetrazolium bromide- MTT test. Results: Samples mostly consisted of spherical and rode-like. The relative viability of cells increased following the exposure time. Conclusion: The biocompatibility of synthesized materials is comparable to the control material MTA+, and therefore these materials can be recommended for further clinical studies.

Fast dendritic cells matured with Poly (I:C) may acquire tolerogenic properties

BACKGROUND AIMS

Because of the labor-intensive and time-consuming conventional protocols for the generation of dendritic cells (DCs) as the most promising tools for anti-cancer therapy that enable the induction of a T-helper (Th)1-mediated anti-tumor immune response, the use of short-term protocols has been proposed. However, data on the applicability of such protocols in cancer immunotherapy are quite limited.

METHODS

We compared the phenotypic and functional capability of fast DCs (fDCs) differentiated for 24 h and then matured for 48 h with Poly (I:C), a strong Th1-promoting agent, with donor-matched conventional DCs (cDCs) differentiated for 5 days and matured likewise.

RESULTS

Of 12 donors tested, we identified seven whose monocytes failed to develop into immunogenic DCs through the use of fDC protocol, on the basis of incomplete downregulation of CD14, low expression of CD1a and macrophage-like morphology. Such fDCs have significantly lower expression of CD83, CD86, CCR7 and CD40, weaker allo-stimulatory Th1- and Th17-polarizing capacity caused by poor production of interleukin (IL)-12p70 and IL-23 and high production of IL-10, and prominent Th2-polarizing capacity, compared with donor-matched cDCs. Furthermore, such fDCs had tolerogenic properties as judged by higher expression of indolamine dioxigenase-3, IDO-1 and IL-1β and induction of a higher percentage of CD4(+)CD25(+)FoxP3(+) T cells. These findings correlated with increased transforming growth factor (TGF)-β production by fDC-primed CD3(+)T cells and their stronger anti-proliferative capacity.

CONCLUSIONS

We emphasize that although fDCs could probably be applied as an alternative to cDCs for cancer therapy, the fDC protocol should not be applied to donors whose DCs acquire tolerogenic capabilities.

Size-dependent effects of gold nanoparticles uptake on maturation and antitumor functions of human dendritic cells in vitro

Gold nanoparticles (GNPs) are claimed as outstanding biomedical tools for cancer diagnostics and photo-thermal therapy, but without enough evidence on their potentially adverse immunological effects. Using a model of human dendritic cells (DCs), we showed that 10 nm- and 50 nm-sized GNPs (GNP₁₀ and GNP₅₀, respectively) were internalized predominantly via dynamin-dependent mechanisms, and they both impaired LPS-induced maturation and allostimulatory capacity of DCs, although the effect of GNP₁₀ was more prominent. However, GNP₁₀ inhibited LPS-induced production of IL-12p70 by DCs, and potentiated their Th2 polarization capacity, while GNP₅₀ promoted Th17 polarization. Such effects of GNP₁₀ correlated with a stronger inhibition of LPS-induced changes in Ca²⁺ oscillations, their higher number per DC, and more frequent extra-endosomal localization, as judged by live-cell imaging, proton, and electron microscopy, respectively. Even when released from heat-killed necrotic HEp-2 cells, GNP₁₀ inhibited the necrotic tumor cell-induced maturation and functions of DCs, potentiated their Th2/Th17 polarization capacity, and thus, impaired the DCs' capacity to induce T cell-mediated anti-tumor cytotoxicity in vitro. Therefore, GNP₁₀ could potentially induce more adverse DC-mediated immunological effects, compared to GNP₅₀.

Prolactin stimulates cell migration and invasion by human trophoblast in vitro

INTRODUCTION

Prolactin (PRL) is present in endometrium at the time of embryo implantation and throughout pregnancy. Extrapituitary PRL acts as a cytokine in cells expressing PRL receptor (PRLR). So far no specific function has been demonstrated for PRL in the trophoblast of early pregnancy.

METHODS

PRLR in placental tissue and trophoblast cells was shown here immunochemically. The possibility that PRL could influence trophoblast cell migration and invasion was investigated in vitro using isolated cytotrophoblast of the first trimester of pregnancy placental tissue and HTR-8/SVneo cell line. Wound healing cell migration test was performed on HTR-8/SVneo cells, and both cell types were used in Matrigel invasion test.

RESULTS

PRLR is expressed by extravillous cytotrophoblast of the cell column and the placental bed, as well as in isolated cytotrophoblast (CT) and HTR-8/SVneo cells. PRL (at 100 and 1000 ng/ml) stimulated HTR-8/SVneo cell migration and cell invasion in both cell types, which could be blocked by anti-PRLR. Integrins α1 and α5, and galectin-1 (gal-1) were variably increased in PRL treated CT and HTR-8/SVneo cells.

DISCUSSION

To our knowledge this is the first study demonstrating that PRL stimulates trophoblast invasiveness through PRLR, which is accompanied by increased integrins and gal-1, not excluding change in other potential mediators. This finding further supports relevance of PRLR for invasive trophoblast.

CONCLUSION

This report supports a possibility that PRL may have a role in trophoblast invasion in vivo.

Immunomodulatory Activity of IL-27 in Human Periapical Lesions

IL-27, a cytokine with pro-inflammatory and anti-inflammatory properties, is a new member of the IL-6/IL-12 family, whose function in periapical lesions is unknown. We hypothesized that the production of IL-27 and its effect depend upon the type of immune/inflammatory response and clinical presentation of periapical lesions. We tested this hypothesis by studying the expression and function of IL-27 in human periapical lesions, both in situ and in culture. Immunohistochemistry demonstrated the strongest expression of IL-27 by endothelial cells and mononuclear phagocytes. Its production by periapical lesion mononuclear cells (PL-MNC), especially in symptomatic lesions, was significantly higher compared with that in peripheral blood MNC and correlated with the frequency of CD14+ and CD3+ cells. Exogenous IL-27 stimulated Th1 and down-regulated Th17 cytokine production by PL-MNC from symptomatic lesions, but down-regulated Th1 and Th2 responses in asymptomatic lesions. These findings suggest that IL-27 is an immunomodulatory cytokine in periapical lesions, with complex biological effects.

Regulatory T-cells in Periapical Lesions

CD4+CD25hiFoxp3+ regulatory T-cells (Tregs) are of crucial importance in regulating the immune response, including the control of any defense against infection. Their presence in periapical lesions has not been demonstrated, as yet. We hypothesized that Tregs infiltrate periapical lesions, where they inhibit T-cell proliferation. The aim of this study was to characterize Tregs in periapical lesions by confocal microscopy, flow cytometry, and functional assays. We showed that CD4+CD25hiFoxp3+ cells in periapical lesions expressed IL-10 and TGF-β. Their frequency was significantly higher than in peripheral blood and correlated with the levels of TGF-β and IL-10 in culture supernatants of periapical lesion mononuclear cells. Tregs inhibited the proliferation of responder T-cells in vitro, at least in part, by stimulating the production of IL-10. These findings suggest that CD4+CD25hiFoxp3+ cells in periapical lesions may play regulatory roles in controlling local immune/inflammatory processes.

Characterization of antigen-presenting cells in human apical periodontitis lesions by flow cytometry and immunocytochemistry

AIM

To analyse phenotypic characteristics of antigen-presenting cells (APC), isolated from human periapical lesions by flow cytometry and immunocytochemistry.

METHODOLOGY

Sixteen periapical lesions were digested for 15 min with 0.05% collagenase. Mononuclear cells, separated from other inflammatory cells by density centrifugation, were processed for flow cytometry and/or immunocytochemistry. Single and double immunostainings were performed using monoclonal antibodies specific for human CD45, CD3, CD19, CD14, HLA-DR, CD1a, CD83 and CD123.

RESULTS

Antigen-presenting cells (HLA-DR(+) cells) represented 32.9 +/- 17.8% of total mononuclear cells. Amongst them, B cells (HLA-DR(+) CD19(+)) were the predominant APC population, followed by activated macrophages (HLA-DR(+) CD14(+)), dendritic cells (DC) (HLA-DR(+) CD14(-) CD19(-) CD3(-)) and activated T cells (HLA-DR(+) CD3(+)). Based on the predominance of T cells (CD3(+)) or B cells and plasma cells (CD19(+) and CD19(lo), respectively) amongst mononuclear cell infiltrates, lesions were divided into T- and B-types. The percentage of DC in T-type lesions (27.1 +/- 6.8% of total HLA-DR(+) cells) was higher, compared with B-type lesions (10.3 +/- 5.2%) (P < 0.01). Within the DC population, the percentages of CD1a (Langerhans cell type) and CD123 (probably plasmacytoid DC type) did not differ significantly between the groups (P > 0.05). However, the percentage of mature DC (CD83(+)) was significantly higher in T-type periapical lesions (P < 0.05).

CONCLUSIONS

Flow cytometry and immunocytochemistry are suitable methods for phenotypic analysis of APC after their isolation from human periapical lesions. APC, that were phenotypically heterogeneous, constituted a significant component of infiltrating cells. Lesions with the predominance of T cells were characterized by a higher proportion of mature DC (HLA-DR(+)CD83(+) cells) than lesions with predominance of B cells/plasma cells.

A nucleoside analogue, 7-thia-8-oxoguanosine stimulates proliferation of thymocytes in vitro

7-thia-8-oxoguanosine (immunosine) is a nucleoside analogue with immunoenhancing activity. In this work, its effects on proliferation of thymocytes in vitro were studied. It was found that immunosine stimulated proliferation of thymocytes both of mice and rats. The stimulatory effect depended on antigen presenting cells (APC), since thymocytes depleted of accessory cells did not proliferate to immunosine. In addition, pretreatment of APC with immunosine for 24 h significantly increased proliferation of thymocytes. Immunosine stimulated interleukin 2 (IL-2) production and the expression of activation markers (CD25 and CD71). The upregulation of CD25 (alpha subunit of IL-2R) was detected both on thymocytes and thymic dendritic cells. Proliferation of thymocytes in the presence of immunosine was predominantly mediated by IL-2 since blocking IL-2Ralpha by specific monoclonal antibodies inhibited cell proliferation by 65-85%.