Formation of extracellular traps by circulating neutrophils and monocytes in rheumatoid arthritis patients: a study of new citrullinated autoantigen

Detection of subcellular structures containing typical citrullinated rheumatoid autoantigens in a single compartment presents a special interest, due to importance of anticitrulline autoantibodies for the autoimmune response in RA. Neutrophil and monocyte extracellular traps (NETs and ETs, respectively) may be considered such candidate structures. Our objective was to assess ability of blood neutrophils and monocytes from RA patients to generate NETs and ETs spontaneously and after in vitro induction.32 patients with verified RA and 30 healthy volunteers as controls were included into the study. Circulating neutrophils and monocytes were isolated with one-step density gradient centrifugation using three layers of ficoll-amidotrizoate gradient. Composition of isolated cellular fractions, their viability, and non-specific activation were evaluated microscopically using Trypan Blue exclusion test, as well as Nitro-Blue Tetrazolium test. The NETs were induced by phorbol-12-myristate-13-acetate, and ETs by bacterial LPS. Spontaneous and induced formation of extracellular traps was assessed using fluorescence microscopy. Neutrophil and monocyte fractions contained minute percentages of impurities and low extents of activated and dead cells. Spontaneous NET and ET formation in RA patients was significantly increased comparing to healthy controls. Neutrophils from ACPA-positive RA patients were found to have higher frequency of NET formation, compared to ACPA-negative RA patients. The monocytes did not demonstrate such differences between these subgroups. There were no substantial morphological differences in NETs and ETs patterns between the individuals from both groups. Induced extracellular trap production in RA was significantly higher compared to healthy controls. The level of myeloperoxidase-specific fluorescence in ETs was considerably lower than in NETs. NETs could probably be considered as a source of citrulline autoantigen participating in autoantibody production and stimulation of inflammatory autoimmune responses in RA, whereas ETs may play less important role in this process.

Viability and DNA Damage of Buccal Mucosa Cells in Patients Exposed to Panoramic X-ray

Panoramic X-ray is well known to cause DNA damage and induces cellular death. The aim of the present study was to evaluate the cytotoxicity of radiation exposure from panoramic radiography on human buccal mucosa cells by assessing the cell viability using the simple-trypan blue exclusion test. The genotoxicity effect was evaluated by assessing comet assay score. This research included a total of 20 healthy patients who had panoramic radiography for a routine dental examination. Buccal mucosa cells were collected from all participants before X-ray exposure and at 30 min or 24 h after exposure in Groups 1 and 2, respectively, and subjected to a comet assay and trypan blue exclusion test to assess cell viability and DNA damage. Cell viability was calculated as the ratio of live (translucent) to total counted cells. Comet assay output images were analysed using OpenComet software and a visual score by measuring the percentages of tail DNA and summing the visual score, respectively. A statistically significant (p < 0.05) reduce in cell viability was observed at 30 min after exposure, furthermore there is no more reduction after 24 h. Both comet assay measurements showed a significant (p < 0.05) increase in the percentage of tail DNA and visual score at 30 min after exposure, then tend to decrease after 24 h of exposure, although it was not significant (p > 0.05). The results showed that panoramic radiography interfered cell viability and induced DNA damage in buccal mucosa cells within 30 min after exposure, but these effects were ceased after 24 h.

Effect of serial photodynamic therapy with curcumin on Leishmania braziliensis and Leishmania amazonensis promastigotes

Photodynamic Therapy (PDT) consists of using a light source and a photosensitive drug at an appropriate wavelength and molecular oxygen to trigger cell death through the production of reactive oxygen species. Because it is a localised therapy, PDT is shown to be ideal for skin diseases. American cutaneous Leishmaniasis (ACL) is a highly prevalent protozoan disease worldwide that presents different clinical evolutions and may result in ulcerations and disfiguring lesions on the skin and cartilage. This study was aimed at evaluating the effect in vitro of PDT applied serially using curcumin as a photosensitiser. For this, a concentration of 125 µg.mL-1 of curcumin was used on Leishmania braziliensis and Leishmania amazonensis strains, with a light fluence of 10 J.cm-2 and irradiance of 110 mW.cm-2. The tests done were viability analysis by trypan blue exclusion test, analysis of photosensitizer (PS) internalization by confocal microscopy and morphological alterations by May-Grunwald/Giemsa staining. We observed that there was internalisation of the PS before the first and second application of PDT, with L. braziliensis and L. amazonensis strains mortality of 92% and 82% respectively, after the second application, and induction of alterations in the structural conformation, such as cell size and non-evidence of nucleus and flagellum, demonstrating that PDT was effective. We conclude that serial PDT was effective in inducing the mortality of promastigotes forms of L. braziliensis and L. amazonensis in vitro, thus highlighting its potential for the treatment of leishmaniasis.

Tissue Harvesting Site Effect on the Canine Adipose Stromal Vascular Fraction Quantity and Quality

Mesenchymal stem cells (MSCs) constitute a great promise for regenerative therapy, but these cells are difficultly recovered in large amounts. A potent alternative is the stromal vascular fraction (SVF), non-cultured MSCs, separated from adipose tissue (AT). We aim to evaluate AT harvesting site effect on the SVF cells’ quantity and quality in dogs. Subcutaneous abdominal fat, falciform ligament and peri-ovarian fat were sampled. After SVF isolation, the trypan blue exclusion test and a hemocytometer were used to assess the cell viability and cellular yield. SVF cells were labeled for four surface antigenic markers, clusters of differentiation CD90, CD44, CD29, and CD45, and then examined by flow cytometry. Semi-quantitative RT-PCR was used to evaluate the gene expression of the former markers in addition to OCT-4 and CD34. SVF cells in the peri-ovarian AT recorded the highest viability% (99.63 ± 0.2%), as well as a significantly higher cellular yield (36.87 ± 19.6 × 106 viable cells/gm fat, p < 0.001) and a higher expression of adipose-derived mesenchymal stem cells AD-MSCs surface markers than that of other sites. SVF cells from the peri-ovarian site revealed a higher expression of MSC markers (CD90, CD44, and CD29) and OCT-4 compared to the other sites, with weak CD45 and CD34 expressions. The positive OCT-4 expression demonstrated the pluripotency of SVF cells isolated from different sites. To conclude, the harvesting site is a strong determinant of SVF cells’ quantity and quality, and the peri-ovarian site could be the best AT sampling site in dogs.

Suitability of a Progenitor Cell-Enriching Device for In Vitro Applications

Rigenera® is a novel class-1 medical device that produces micro-grafts enriched of progenitors cells without ex vivo manipulation of donor tissues. The manufacturer’s protocol has been supported for a wide variety of clinical uses in the field of regenerative medicine. This study aimed to evaluate its potential use for in vitro cell models. Human primary oral fibroblasts were cultured under standard conditions and processed through Rigenera® over a time course of up to 5 min. Cell viability was assessed using a Trypan Blue exclusion test. It is possible to process fibroblasts through Rigenera® although an initial reduction of cell viability was observed. Additionally, debris was evident in the cell suspension of the processed samples. Scanning electron microscopy (SEM) microanalysis of the debris and electron energy-loss spectroscopy confirmed the presence of metal wear possibly due to the processing conditions used in this study. Interestingly, pore sizes within Rigeneracons® grids were found to range between 250–400 μm. This is the first report assessing the suitability of Rigenera® and Rigeneracons® for in vitro applications. Whilst Rigenera® workflow was found to be amenable to laboratory uses, our results strongly suggest that further research and development is necessary to support the utilization of this technology for enrichment of micro-graft derived cells and cell sorting in vitro.

Response of human oral mucosal epithelial cells to different storage temperatures: A structural and transcriptional study

Purpose Seeking to improve the access to regenerative medicine, this study investigated the structural and transcriptional effects of storage temperature on human oral mucosal epithelial cells (OMECs). Methods Cells were stored at four different temperatures (4°C, 12°C, 24°C and 37°C) for two weeks. Then, the morphology, cell viability and differential gene expression were examined using light and scanning electron microscopy, trypan blue exclusion test and TaqMan gene expression array cards, respectively. Results Cells stored at 4°C had the most similar morphology to non-stored controls with the highest viability rate (58%), whereas the 37°C group was most dissimilar with no living cells. The genes involved in stress-induced growth arrest (GADD45B) and cell proliferation inhibition (TGFB2) were upregulated at 12°C and 24°C. Upregulation was also observed in multifunctional genes responsible for morphology, growth, adhesion and motility such as EFEMP1 (12°C) and EPHA4 (4°C–24°C). Among genes used as differentiation markers, PPARA and TP53 (along with its associated gene CDKN1A) were downregulated in all temperature conditions, whereas KRT1 and KRT10 were either unchanged (4°C) or downregulated (24°C and 12°C; and 24°C, respectively), except for upregulation at 12°C for KRT1. Conclusions Cells stored at 12°C and 24°C were stressed, although the expression levels of some adhesion-, growth- and apoptosis-related genes were favourable. Collectively, this study suggests that 4°C is the optimal storage temperature for maintenance of structure, viability and function of OMECs after two weeks.

Doxyl Nitroxide Spin Probes Can Modify Toxicity of Doxorubicin towards Fibroblast Cells

The biological properties of doxyl stearate nitroxides (DSs): 5-DS, Met-12-DS, and 16-DS, commonly used as spin probes, have not been explored in much detail so far. Furthermore, the influence of DSs on the cellular changes induced by the anticancer drug doxorubicin (DOX) has not yet been investigated. Therefore, we examined the cytotoxicity of DSs and their ability to induce cell death and to influence on fluidity and lipid peroxidation (LPO) in the plasma membrane of immortalised B14 fibroblasts, used as a model neoplastic cells, susceptible to DOX-induced changes. The influence of DSs on DOX toxicity was also investigated and compared with that of a natural reference antioxidant α-Tocopherol. By employing the trypan blue exclusion test and double fluorescent staining, we found a significant level of cytotoxicity for DSs and showed that their ability to induce apoptosis and modify plasma membrane fluidity (measured fluorimetrically) is more potent than for α-Tocopherol. The most cytotoxic nitroxide was 5-DS. The electron paramagnetic resonance (EPR) measurements revealed that 5-DS was reduced in B14 cells at the fastest and Met-12-DS at the slowest rate. In the presence of DOX, DSs were reduced slower than alone. The investigated compounds, administered with DOX, enhanced DOX-induced cell death and demonstrated concentration-dependent biphasic influence on membrane fluidity. A-Tocopherol showed weaker effects than DSs, regardless the mode of its application—alone or with DOX. High concentrations of α-Tocopherol and DSs decreased DOX-induced LPO. Substantial cytotoxicity of the DSs suggests that they should be used more carefully in the investigations performed on sensitive cells. Enhancement of DOX toxicity by DSs showed their potential to act as chemosensitizers of cancer cells to anthracycline chemotherapy.

683. Assessment of Biofilm Eradication and Cytotoxicity of a Novel Polygalacturonic Acid + Caprylic Acid Wound Ointment Compared with Antiseptic Wound Ointments

Background Antiseptic wound ointments are increasing importance from safety, microbiological and public health points of view. Previously, Rosenblatt et al. (2017) has assessed polygalacturonic acid (PG) + caprylic acid (CAP) solution for biofilm eradication efficacy and cytotoxicity. In this study, we assessed biofilm eradication and cytotoxicity of PG+CAP wound ointment compared with commercially available wound ointment comparators. Methods Assessment of antimicrobial efficacy was conducted using a well-established biofilm model. Twenty-four-hour biofilm was formed on silicone discs and exposed wound ointments for 2 hours. Discs were then sonicated and cultured to quantitate any remaining viable biofilm. To assess cytotoxic effects of wound ointments, L-929 fibroblasts were exposed to 2% extracts of each ointment. The trypan exclusion test was used to access cell viability and Alamar blue was used to assess metabolic function. Ointments tested include, PG+CAP formulated in an inert ointment base, benzalkonium chloride quaternary ammonia antiseptic ointment (BZK), polyhexamethylene biguanide (PHMB) antiseptic ointment, and 2-hydroxyethylcellulose + glycerol inert ointment base. Untreated fibroblast cells were used as controls. Results Within 2 hours of exposure, PG+CAP ointment able to completely eradicate C. albicans (CA), MDR Pseudomonas aeruginosa (PS), and MRSA. Additionally, PG+CAP was significantly more efficacious than BZK for MRSA (P = 0.002) and PS (P = 0.015) and PHMB for MRSA (P = 0.02). In the trypan blue exclusion test PG+CAP yielded 96.29% viable cells compared with 77.83% and 83.25%, for the QUAT and PHMB ointments, respectively. Fibroblasts treated with 2% PG+CAP, retained 86.6% of metabolic activity compared with untreated cells while the QUAT and PHMB ointments retained 37.5% and 44.5% metabolic activity, respectively. Conclusion PG+CAP has enhanced effects on eradication of biofilm in vitro as well as less toxicity in vitro relative to the antiseptic wound ointments. Further in vivo studies are warranted. Disclosures All authors: No reported disclosures.

Assessment of genotoxic effects of a fungicide product and its active substances on human peripheral blood mononuclear cells

The genotoxic potential of the plant protection product Signum? and its two active substances (pyraclostrobin and boscalid) was investigated by the comet assay (pH>13). Leukocytes isolated from whole blood were treated with different concentrations (0.1-25 ?g/ml) of the fungicide for 2 h and 20 h. The Trypan Blue exclusion test showed higher cell viability (>84%) under all three concentrations and in the two treatment periods. The obtained results revealed that both Signum? and pyraclostrobin induced statistically significant DNA damage. In contrast, boscalid did not cause statistically significant DNA damage after 2 h exposure although it caused DNA damage at higher concentrations after a longer time exposure (20 h). It is deducible that pyraclostrobin and Signum? might be genotoxic. However, within the studied concentration ranges, none of the fungicides was found to be cytotoxic in the two treatment periods.

In-vitro Labelling of Ovine Adipose-Derived Mesenchymal Stem Cells (oADMSCs) and Tracking Using MRI Technique

To understand the mechanisms standing behind a successful stem cell-based therapy, the monitoring of transplanted cell’s migration, homing as well as the engraftment efficiency and functional capability in-vivo has become a critical issue. The present study was designed to track the labelled oADMSCs in-vitro and its visualization through MRI technique. oADMSCs from passage 4 (P-4) to passage 6 (P-6) were labelled with superparamagnetic iron oxide (SPIO) conjugated with rhodamine (Molday Ion Rhodamine-B - MIRB) at the concentration of 25μg Fe/ml in DMEM. Internalized MIRB was observed under fluorescent microscope after 72 hrs of incubation. Labelled oADMSCs showed Prussian Blue positive reaction demonstrating the iron uptake of the cells. The viability of the MIRB-labelled oADMSCs ranged between 98-99 per cent and Trypan blue exclusion test showed no significant difference in viability between labelled and unlabelled oADMSCs. MR signal in control group of cells was similar to that of water. MR signals or fluorescence in MIRB-labelled cells decreased with increasing concentrations of iron. The T2 weighted images of MIRB-labelled oADMSCs increased with increasing concentrations of SPIOs. The MIRB was found to be nontoxic, and did not affect proliferation capacity in-vitro.