Cell Viability Of Samples Research Articles

Bioprinting-Associated Shear Stress and Hydrostatic Pressure Affect the Angiogenic Potential of Human Umbilical Vein Endothelial Cells

Bioprinting-associated shear stress and hydrostatic pressure can negatively affect the functionality of dispensed cells. We hypothesized that these mechanical stimuli can potentially affect the angiogenic potential of human umbilical vein endothelial cells (HUVECs). A numerical simulation model was used to calculate the shear stress during microvalve-based droplet ejection. The impact of different levels of applied pressure and the resulting shear stress levels on the angiogenic potential of HUVECs was investigated after up to 14 days of cultivation. In vitro results showed that bioprinting-associated stress not only has short-term but also long-term effects. The short-term viability results indicate a 20% loss in post-printing cell viability in samples printed under the harshest conditions compared to those with the lowest shear stress level. Further, it was revealed that even in two-dimensional culture, HUVECs were able to form a capillary-like network organization regardless of bioprinting pressure. In three-dimensional culture experiments; however, the HUVECs printed at 3 bar were not able to form tubular structures due to their exposure to high shear stress levels. In conclusion, this study provides new insights into how the bioprinting process should be conducted to control printing-associated shear stress and hydrostatic pressure to preserve the functionality and angiogenetic potential of HUVEC.

The Effects of Curcumin Nanoparticles Incorporated into Collagen-Alginate Scaffold on Wound Healing of Skin Tissue in Trauma Patients.

Wound healing is a biological process that is mainly crucial for the rehabilitation of injured tissue. The incorporation of curcumin (Cur) into a hydrogel system is used to treat skin wounds in different diseases due to its hydrophobic character. In this study, sodium alginate and collagen, which possess hydrophilic, low toxic, and biocompatible properties, were utilized. Collagen/alginate scaffolds were synthesized, and nanocurcumin was incorporated inside them; their interaction was evaluated by FTIR spectroscopy. Morphological studies investigated structures of the samples studied by FE-SEM. The release profile of curcumin was detected, and the cytotoxic test was determined on the L929 cell line using an MTT assay. Analysis of tissue wound healing was performed by H&E staining. Nanocurcumin was spherical, its average particle size was 45 nm, and the structure of COL/ALG scaffold was visible. The cell viability of samples was recorded in cells after 24 h incubation. Results of in vivo wound healing remarkably showed CUR-COL/ALG scaffold at about 90% (p < 0.001), which is better than that of COL/ALG, 80% (p < 0.001), and the control 73.4% (p < 0.01) groups at 14 days/ The results of the samples’ FTIR indicated that nanocurcumin was well-entrapped into the scaffold, which led to improving the wound-healing process. Our results revealed the potential of nanocurcumin incorporated in COL/ALG scaffolds for the wound healing of skin tissue in trauma patients.

The common gamma-chain cytokines IL-2, IL-7 and IL-15 impact on proliferation of lymphocytes in vitro in breast cancer patients.

e13060 Background: Monotherapy with low doses of cytokines does not provide significant therapeutic results, while treatment with high doses leads to a number of side effects, for example, cytokine release syndrome, etc. Therefore, it is necessary to study the effect of cytokines on immune cells which are involved in the regulation of pro- and antitumor immune response. Thus, the aim of this study was to analyze the dynamics in the proliferation of the total fraction of lymphocytes after expansion and exposure to γc-cytokines: IL-2, IL-7 and IL-15 and their combinations in vitro in patients with diagnosed breast cancer. Methods: The study included 10 patients with locally advanced stage I-III breast cancer. Peripheral blood mononuclear cells (PBMC, ficoll-hypaque) were used as material. After density separation the cells were cultured at a dose of 500 thousand cells / ml in 6-well plates (Biofil, China) in RPMI 1640 (Gibco, USA) supplemented with 10% FBS (HyClone, USA) at 37° C, 5% CO2. Expansion of lymphocytes was performed by kit with anti-biotin magnetic particles MACSiBead to CD2, CD3 and CD28 (Miltenyi Biotec, Germany), according to the manufacturer's protocol. Stimulation of lymphocyte proliferation was performed on days 4, 8 and 12 by introducing recombinant cytokines - IL-2, IL-7, IL-15 (Miltenyi Biotec, Germany) and their combinations. Cytokines were introduced at a concentration of 40 ng / ml each in the following variants: IL-2; IL-2 / IL-15; IL-2 / IL-15 / IL-7; IL-15; IL-15 / IL-7. Plates with cell suspension were cultured at 37 ° C, 5% CO2 for 15 days. Results: The data obtained on the 11th day of incubation demonstrated statistically significant differences in cell viability in samples with the addition of interleukin IL-7 / IL-15 combination (778%) compared to control samples by 1.5 times (p &lt; 0.05). The proportion of lymphocytes in samples with the addition of only IL-15 (702%) and IL-7 / IL-15 (756%) combination was 1.47 and 1.6 times higher, respectively, compared with the control (p &lt; 0.05) at the 12th day of co-cultivation. Conclusions: Stimulation of lymphocyte proliferation by the IL-7 / IL-15 combination results in a high frequency of viable cell production. Despite the only culture stage, the results of the study may be important for optimizing the use of γc-cytokines in the treatment of patients with breast cancer.

Biofabrication and Characterization of Alginate Dialdehyde-Gelatin Microcapsules Incorporating Bioactive Glass for Cell Delivery Application.

The effect of the incorporation of 45S5 bioactive glass (BG) microparticles (mean particle size ≈2µm) on the fabrication and physicochemical properties of alginate dialdehyde-gelatin hydrogel capsules is investigated. The addition of BG particles decreases the hydrogel gelation time by ≈79% and 91% for the samples containing 0.1% w/v and 0.5% w/v BG, respectively. Moreover, it results in increasing average diameter of hydrogel capsules produced via a pressure-driven extrusion technique from about 1000µm for the samples without BG to about 1700 and 1900µm for the samples containing BG at concentrations of 0.1% w/v and 0.5% w/v, respectively. The presence of BG particles in the capsules decreases the degradation rate and improves the bioactivity of the materials. The viability of MG-63 cells encapsulated in all samples increases during the first 7d of cultivation and maintains the same level during 21d of cultivation. The early cell viability in samples containing BG is lower than that in samples without BG. The results show that 45S5 BG can positively regulate the osteogenic activity of cells incorporated in hydrogel capsules. The fabricated composite capsules exhibit promising potential for cell delivery in bone regeneration applications.

Biocompatibility and hyperthermia cancer therapy of casein‐coated iron oxide nanoparticles in mice

Magnetic nanoparticles (MNPs) can be used as heat generation source in cancer hyperthermia therapy. While iron oxide nanoparticles (NPs) are the most popular choice for magnetic hyperthermia, adding a surface enhancement can improve its performance. Furthermore, for MNPs to be used in biomedical application their cytotoxicity needs to be evaluated. In this study biocompatibility and also in vivo performance of casein‐coated MNPs were assessed. Cell viability of normal cell lines in all of tests remained above 95% for 0.5 and 1 mg/mL concentration and even the minimum recorded cell viability for normal cell lines was 84.78% at 20 mg/mL concentration. In contrast cell viability of cancer cell lines in contact with casein coated MNPs core‐shell structure except for one sample remained below 85%. By introduction of and alternating magnetic field, cell viability of samples with lower MNP concentration dropped by 20% to 30% while this drop for samples with higher concentration was 10% to 20%. Furthermore, results of in vivo trials show that just 1 week of hyperthermia treatment with casein coated MNPs core‐shell structure can reduce the tumor size of the mice by 33%. Real‐time polymerase chain reaction results further confirmed the effectiveness of this method. Moreover, findings of this study suggest that lower injection speed can improve NPs distribution and treatment effect. Results of this study suggest that core‐shell structure can positively affect the tumor growth and the combination of good biocompatibility, innate hostility toward cancer cells and good heating power makes them a good candidate for hyperthermia cancer therapy applications.

Ibrutinib and Venetoclax Target Distinct Subpopulation of CLL Cells: Rationale for Drug Combination and Implication of Minimal Residual Disease Eradication

Ibrutinib (Ibr) is a specific inhibitor of Bruton tyrosine kinase, a component of the B-cell receptor (BCR) signaling. Venetoclax (Veneto) inhibits the anti-apoptotic protein BCL2. Both drugs are highly effective as monotherapy against chronic lymphocytic leukemia (CLL) (Byrd NEJM, Roberts, NEJM, 2015 and Roberts, Blood, 2019) and clinical trials using the combination therapy are ongoing. An interesting clinical observation is that the tumor cell sensitivity to these two drugs differ between different anatomic compartments. While lymph node-resident CLL cells are more sensitive to ibr, circulating CLL cells in the peripheral blood are more sensitive to the action of veneto. When these two drugs are used in combination to treat relapsed/refractory (Hillman ASH 2018 and Kater EHA 2019) or previously untreated CLL patients (Jain NEJM 2019), rate of complete response significantly increases compared to single drug alone. Moreover, negativity of bone marrow minimal residual disease continues to improve over time. However, the reason behind these observed compartmental responses is largely unknown, and we investigated the differential response using an ex vivo model that promotes CLL proliferation (CLL proliferation model). A better understanding of how these two drugs synergize would eventually help develop other rational combination strategies. We established the ex vivo model using fibroblasts derived from the bone marrow of a CLL patient. In this model, CLL cells closely interact with the bone marrow fibroblasts (BMF) (Fig.1) and divide and proliferate for several generations, as measured by CFSE labeling. The culture, in some cases, may continue for 10 weeks before cell death ensues. With this ability to promote long-term cell proliferation, the model recapitulates one of the most salient features observed histologically in the "proliferation centers" of the CLL lymph nodes. With the proliferation model, we first tested the effects of ibrutinib on cell division/proliferation as well as cell viability in samples taken from 30 CLL patients consisting of 22 ibr-naïve (thus sensitive) and 8 ibr-relapsed (thus resistant) patients. We demonstrate that there was lack of a significant inhibition of ibr on cell viability. In comparison, Ibr markedly inhibited cell proliferation in cells from ibr-naïve/sensitive patients (p&amp;lt;0.0001), while such inhibition was much less prominent in cells from ibr-relapsed/resistant patients (p=0.053). Overall, our data demonstrate that only the dividing subpopulation of CLL responds to ibr, and this response is highly correlated with patients' clinical response to the drug while cell viability responses are not. With the CLL proliferation model, we also evaluated how veneto works. Veneto, as expected, markedly decreased cell viability at clinically achievable concentrations. CFSE profiles of the remaining live cells, however, revealed an interesting pattern of distribution, showing that veneto induces cell death but it preferentially kills the resting CLL population (Fig. 2). In other words, the resting subpopulation of CLL, instead of the dividing one, preferentially responds to veneto as compared to ibr. Combination of the two drugs, as expected, worked most effectively, significantly reducing the total number of live cells, both resting and dividing subpopulations, in all cases. Analyses of CFSE profiles became less meaningful in many of these cases due to the small number of live cells remaining after the combination treatment. In conclusion, our study, comparing the actions of ibr and veneto in a clinically relevant CLL proliferation model, demonstrates for the first time that the drugs target distinct subpopulations of CLL cells with different proliferative capacity. The data also suggest that single drug therapy may leave a subpopulation behind that would potentially rise to cause a future relapse. Our study provides a strong laboratory rationale explaining why combining these two drugs has the potential to eradicate CLL disease. The findings are also in line with the clinical observations regarding the compartmental response; ibrutinib works primarily on the lymph nodes where CLL cells divide in the "proliferation centers" and veneto acts preferentially on the circulating CLL cells that are mostly non-dividing and resting. Disclosures Wang: Incyte Reaserch Institute: Employment. Ma:Abbvie: Research Funding; Xeme: Research Funding; Novartis: Research Funding; Bioverativ: Consultancy; Janssen: Consultancy, Speakers Bureau; Beigene: Research Funding; Kite: Consultancy; Gilead: Research Funding; Pharmacyclics: Consultancy, Research Funding, Speakers Bureau; Acerta: Research Funding; Astra Zeneca: Consultancy, Research Funding, Speakers Bureau; Genentech: Consultancy; Incyte: Research Funding; Juno: Research Funding. Larson:Celgene: Consultancy; Agios: Consultancy; Novartis: Honoraria, Other: Contracts for clinical trials.

Intracellular trehalose and sorbitol synergistically promoting cell viability of a biocontrol yeast, Pichia anomala, for aflatoxin reduction.

Pichia anomala (Wickerhamomyces anomalus) WRL-076 was discovered by a visual screening bioassay for its antagonism against Aspergillus flavus. The yeast was shown to significantly inhibit aflatoxin production and the growth of A. flavus. P. anomala is a potential biocontrol agent for reduction of aflatoxin in the food chain. Maintaining the viability of biocontrol agents in formulated products is a great challenge for commercial applications. Four media, NYG, NYGS, NYGT and NYGST are described which support good growth of yeast cells and were tested as storage formulations. Post growth supplement of 5 % trehalose to NYGST resulted in 83 % viable yeast cells after 12 months in cold storage. Intracellular sorbitol and trehalose concentrations were determined by HPLC analysis at the beginning of the storage and at the end of 12 month. Correlation of cell viability to both trehalose and sorbitol suggested a synergistic effect. Bonferroni (Dunn) t Test, Tukey's Studentized Range (HSD) Test and Duncan's Multiple Range Test, all showed that yeast cell viability in samples with both intracellular trehalose and sorbitol were significantly higher than those with either or none, at a 95 % confidence level. DiBAC4(5) and CFDA-AM were used as the membrane integrity fluorescent stains to create a two-color vital staining scheme with red and green fluorescence, respectively. Yeast cells stored in formulations NYG and NYGS with no detectable trehalose, displayed mostly red fluorescence. Yeast cells in NYGST+5T showed mostly green fluorescence.

In Vitro Evaluation of Acellular Dermal Matrix as a Three‐Dimensional Scaffold for Gingival Fibroblasts Seeding

Tissue engineering principles could improve the incorporation of acellular dermal matrix (ADM). The aim of this study is to verify if ADM is a suitable three-dimensional matrix for gingival fibroblasts and cancerous cells ingrowth, and also if cultured medium conditioned in ADM affect cellular behavior. Canine gingival fibroblasts (CGF), human gingival fibroblasts (HGF), and murine melanoma cell line (B16F10) were seeded on ADM for up to 14 days. The following parameters were assessed: morphology and distribution of CGF, HGF, and B16F10; CGF and HGF viability; and the effect of ADM conditioned medium (CM) on CGF viability. Epifluorescence revealed that CGF were unevenly distributed on the ADM surface, showing no increase in cell number over the periods of study; HGF formed a monolayer on the ADM surface in a higher number at 14 days (P <0.05); B16F10 exhibited an increase in cell number within 7 days (P <0.05), and were mainly arranged in cell aggregates on the ADM, forming a continuous layer at 14 days. A higher percentage of cells on the ADM surface (P <0.05) compared to inside was observed for all cell types. 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) values indicated higher cell viability in samples cultured with HGF compared to CGF (P = 0.024). A significantly lower cell viability for CGF grown in CM compared to cells grown in non-CM was observed at 48 and 72 hours (P <0.05). ADM is not suitable as a three-dimensional matrix for gingival fibroblasts ingrowth. Gingival fibroblasts and highly proliferative cells as B16F10 can only be superficially located on ADM, and CGF are negatively affected by culture medium conditioned in ADM, reducing its viability.

Influence of freeze-drying conditions on survival of Oenococcus oeni for malolactic fermentation

Malolactic fermentation (MLF) is an important process in wine production. Oenococcus oeni is most often responsible for MLF. Starter culture technology, involving the inoculation of O. oeni into wines, has been developed for inducing MLF. In this study, the effects of cell washing, pH of suspension medium, preincubation in sodium glutamate, initial cell concentration and freezing temperature on viability of freeze-dried O. oeni H-2 were investigated. The cell viability of samples without washing with potassium phosphate buffer was significantly lower than those samples undergone washing. When pH of suspension medium was 7.0 the cell survival was the highest. The cell viability was enhanced when the cells were preincubated at 25 °C before freezing. When 2.5% sodium glutamate was used as protective agent in suspension medium, the optimal initial cell concentration was 10 9 CFU/ml. The cell viability increased by 21.6% as freezing temperature decreased from − 20 °C to − 65 °C. However, when the cells were frozen in liquid nitrogen (− 196 °C), the cell survival significantly decreased.