Assessing the Cytotoxicity of TiO2-x Nanoparticles with a Different Ti3+(Ti2+)/Ti4+ Ratio.

Titanium dioxide (TiO2) nanoparticles are promising biomedical agents characterized by good biocompatibility. In this study, we explored the cytotoxicity of TiO2-x nanoparticles with a different Ti3+(Ti2+)/Ti4+ ratio and analyzed the efficiency of eryptosis indices as a tool in nanotoxicology. Two types of TiO2-x nanoparticles (NPs) were synthesized by the hydrolysis of titanium alkoxide varying the nitric acid content in the hydrolysis mixture. Transmission electron microscopy (TEM) images show that 1-TiO2-x and 2-TiO2-x NPs are 5 nm in size, whereas X-ray photoelectron spectroscopy (XPS) reveals different Ti3+ (Ti2+)/Ti4+ ratios in the crystal lattices of synthesized NPs. 1-TiO2-x nanoparticles contained 54% Ti4+, 38% Ti3+, and 8% Ti2+, while the relative amount of Ti4+ and Ti3+ in the crystal lattice of 2-TiO2-x nanoparticles was 63% and 37%, respectively. Cell viability and cell motility induced by TiO2-x nanoparticles were investigated on primary fibroblast cultures. Eryptosis modulation by the nanoparticles along with cell death mechanisms was studied on rat erythrocytes. We report that both TiO2-x nanoparticles do not decrease the viability of fibroblasts simultaneously stimulating cell migration. Data from in vitro studies on erythrocytes indicate that TiO2-x nanoparticles trigger eryptosis via ROS- (1-TiO2-x) and Ca2+-mediated mechanisms (both TiO2-x nanoparticles) suggesting that evaluation of eryptosis parameters is a more sensitive nanotoxicological approach for TiO2-x nanoparticles than cultured fibroblast assays. TiO2-x nanoparticles are characterized by low toxicity against fibroblasts, but they induce eryptosis, which is shown to be a promising tool for nanotoxicity screening. The Ti3+ (Ti2+)/Ti4+ ratio at least partly determines the cytotoxicity mechanisms for TiO2-x nanoparticles.

Food additive E407a stimulates eryptosis in a dose-dependent manner.

BACKGROUND: Concerns about the biosafety of the common food additive E407a have been raised. It has been demonstrated to induce intestinal inflammation, accompanied by activation of apoptosis, upon oral exposure. Thus, it is of interest to investigate how E407a affects eryptosis, a suicidal cell death mode of red blood cells. OBJECTIVE: To evaluate the effects of semi-refined carrageenan (E407a) on eryptosis. METHODS: Flow cytometry was employed to assess eryptosis in blood exposed to various concentrations of E407a (0 g/L, 1 g/L, 5 g/L, and 10 g/L) during incubation for 24 h by analyzing phosphatidylserine externalization in erythrocytes using annexin V staining and via evaluating reactive oxygen species (ROS) generation using 2',7'-dichlorodihydrofluorescein diacetate (H2DCFDA). In addition, the eryptosis indices mentioned above were determined in rats orally administered E407a at a dose of 140 mg/kg weight for 2 weeks. Confocal scanning laser microscopy was performed to visualize cell membrane scrambling. RESULTS: Oral intake of E407a for 2 weeks by rats was not associated with membrane scrambling in erythrocytes. However, ROS overproduction was observed. Meanwhile, incubation of blood with various concentrations of semi-refined carrageenan resulted in a dose-dependent promotion of eryptosis, evidenced by the enhanced percentage of annexin V-positive erythrocytes and higher mean fluorescence intensity (MFI) values of annexin V-FITC in all erythrocytes. The highest concentration of E407a promotes a statistically significant increase in ROS generation in erythrocytes, suggesting the role of ROS-mediated induction of eryptosis in this case. CONCLUSION: Incubation of blood with the food additive E407a leads to the activation of eryptosis in a dose-dependent manner. ROS-mediated mechanisms are partially responsible for E407a-induced eryptosis.

Semi-refined carrageenan promotes generation of reactive oxygen species in leukocytes of rats upon oral exposure but not in vitro.

AIM: To assess the ability of the common food additive E407a (semi-refined carrageenan) to enter leukocytes in vitro and generate reactive oxygen species (ROS) in leukocytes as a whole and granulocytes in particular, both during incubation and in experimental animals. METHODS: ROS production was assessed in leukocytes incubated with E407a for 2 h at the final concentrations of 5 and 10 g/L using the dye 2',7'-dichlorodihydrofluorescein diacetate (H2DCFDA), as well as in cells isolated from rats orally exposed to E407a (140 mg/kg of weight) during 2 weeks (n = 8) and control rats (n = 8), by flow cytometry. Carrageenan uptake by leukocytes was estimated by confocal microscopy using incubation of rhodamine B isothiocyanate-labelled carrageenan with leukocyte suspensions. RESULTS: Uptake of carrageenan by viable neutrophils, monocytes, and lymphocytes was confirmed. Oral administration of the food additive E407a was associated with excessive ROS formation by viable leukocytes (CD45+, 7­aminoactinomycin D- cells) and especially in granulocytes. Unexpectedly, a direct impact of semi-refined carrageenan during incubation for 2 h did not affect ROS production in leukocytes, evidenced by statistically insignificant differences in mean fluorescence intensity values of 2',7'-dichlorofluorescein, which is a ROS-sensitive product of intracellular H2DCFDA conversion. Oral intake of E407a and direct exposure of leukocyte suspensions to it decreased the viability of leukocytes. CONCLUSION: Food-grade carrageenan can enter leukocytes without affecting ROS generation as a result of incubation for 2 h with leukocyte suspensions. On the contrary, oral exposure to E407a is accompanied by ROS overproduction by white blood cells, suggesting an indirect mechanism for the stimulation of ROS synthesis in vivo. E407a promotes cell death of leukocytes both in vivo and in vitro.

The relationship of vip level with cardiopulmonary parameters in patients with chronic obstructive pulmonary disease in combination with hypertension.

OBJECTIVE: Introduction: Chronic obstructive pulmonary disease (COPD) with hypertension occupy a leading position in morbidity and mortality in the world. The question of studying a single pathological way of their development, the search for diagnostic markers and therapeutic targets in this comorbid pathology remains relevant. The aim of the study was to study cardiopulmonary parameters in patients with chronic obstructive pulmonary disease with concomitant hypertension, depending on the level of vasoactive intestinal peptide (VIP). PATIENTS AND METHODS: Materials and methods: 99 patients with COPD GOLD 2 were examined, 54 of whom had concomitant hypertension II stage, in which the dependence of lipid metabolism, spirometry and hemodynamic parameters, depending on the level of VIP in blood serum. RESULTS: Results and conclusions: It was established that the smallest values of VIP and the greatest changes in cardiopulmonary parameters, lipid metabolism were found in the cohort of persons with concomitant hypertension. There was a significant decrease in spirometry values and an increase in hemodynamic parameters, respectively, a decrease in VIP levels in patients with COPD in combination with hypertension, which may indicate its role in the formation of these pathologies due to a decrease in its protective function, both in relation to apoptosis of alveolar cells and in relation to progression atherosclerosis and high blood pressure. It was also noted that in patients with the lowest VIP serum levels, a more rapid formation of COPD was observed. The data obtained make it possible to consider VIP as a diagnostic marker and a potential therapeutic target for the comorbid pathology examined.