Marine Polysaccharides Carrageenans Enhance Eryptosis and Alter Lipid Order of Cell Membranes in Erythrocytes

Aim In the current study, hemocompatibility of three major commercially available types of carrageenans (ι, κ and λ) was investigated focusing on eryptosis.

MATERIALS AND METHODS

Carrageenans of ι-, κ- and λ-types were incubated with washed erythrocytes (hematocrit 0.4%) at 0-1-5-10 g/L for either 24 h or 48 h. Incubation was followed by flow cytometry-based quantitative analysis of eryptosis parameters, including cell volume, cell membrane scrambling and reactive oxygen species (ROS) production, lipid peroxidation markers and confocal microscopy-based evaluation of intracellular Ca2+ levels, assessment of lipid order in cell membranes and the glutathione antioxidant system. Confocal microscopy was used to assess carrageenan cellular internalization using rhodamine B isothiocyanate-conjugated carrageenans.

RESULTS

All three types of carrageenans were found to trigger eryptosis. Pro-eryptotic properties were type-dependent and λ-carrageenan had the strongest impact inducing phosphatidylserine membrane asymmetry, changes in cell volume, Ca2+ signaling and oxidative stress characterized by ROS overproduction, activation of lipid peroxidation and severe glutathione system depletion. Eryptosis induction by carrageenans does not require their uptake by erythrocytes. Changes in physicochemical properties of cell membrane were also type-dependent. No carrageenan-induced generation of superoxide and hydroxyl radicals was observed in cell-free milieu.

CONCLUSIONS

Our findings suggest that ι-, κ- and λ-types trigger eryptosis in a type-dependent manner and indicate that carrageenans can be further investigated as potential eryptosis-regulating therapeutic agents.

TOBACCO SMOKING AMONG TEENAGE GIRLS AS A MEDICAL PROBLEM IN MODERN UKRAINE

Purpose of the study - based on objective tests, to clarify the true prevalence and medical and social aspects of tobacco smoking of adolescent girls in the regional center of the east of Ukraine. Anonymous survey of 60 students of 10-11 grades of a secondary school of Kharkov at the age of 14-16 years was conducted. To objectivize the contact with the combustion products of tobacco, the survey was supplemented with a quantitative determination of the concentration of thiocyanide ions in the urine of the respondents. The content of the latter in the urine to 3 mg/l was considered as background (negative), 3-4 mg/l as borderline, and more than 4 mg/l as a positive result. Determining the concentration of thiocyanide ions in the urine of the surveyed showed that 21 people out of 60 (35%) have direct contact with the combustion products of tobacco (thiocyanaturia within 4.13-9.01 mg/l); 17 out of 60 (28.3%) adolescent girls are active smokers, and 12 out of 17 give true information about their habit in questionnaires. The control group consisted of 39 people with a thiocyanaturia level of 0.68-3.47 mg/l, which indicates the absence of contact with tobacco smoke. Among the factors that influence the formation of the behavior of adolescent girls, the highest importance is the high welfare of the family, which entails the presence of a large amount of uncontrolled "pocket" money from a child, which is legalized not only by tobacco smoking, but also by the use of alcoholic beverages: smokers vs. 15% non-smokers (p<0.05) systematically use alcohol. All, without exception, smokers are exemplified by friends and acquaintances, which greatly exceeds the degree of influence of relatives. A provocative role is also played by the proximity of retail outlets selling small tobacco products to the school, combined with the lack of the teacher's control. 35% of school girls between the ages of 14 and 16 years systematically have direct contact with tobacco smoke, 28.3% are active smokers. The presence of sufficiently large amounts of uncontrolled «pocket» money can be the foundation for the emergence and further reproach of the smoking habit. This is facilitated by communication with friends, smokers and the availability of tobacco products in retail outlets near the school.