Effect of the water-soluble cholesterol-methyl-β-cyclodextrin complex on the development of pulmonary edema with an analysis of the osmotic resistance of erythrocytes in rats

Introduction. Methyl-β-cyclodextrin is a potent acceptor of cellular membrane cholesterol and, at the same time, used as a solubilizer, which makes it a potential target for targeted delivery of hydrophobic compounds.Aim. To assess the effect of administration of methyl-β-cyclodextrin containing cholesterol on the degree of lung hydration and osmotic resistance of erythrocytes against the background of pulmonary edema in adult rats caused by the administration of mezaton.Materials and methods. We investigated the degree of hydration of the lungs by the value of the pulmonary coefficient and their dry residue. Osmotic resistance of erythrocytes were assessed by the intensity of their hemolysis in a series of hypotonic sodium chloride solutions in adult male Wistar rats (220±40 g) of the control group (intact, n=10) and two experimental groups with pulmonary edema caused by the administration of mezaton (n=10) and with the subsequent introduction of a water-soluble complex cholesterol-methyl-β-cyclodextrin against the background of the development of pulmonary edema (n=10). We used additional criteria for assessing the osmotic resistance of erythrocytes: minimum resistance – the concentration of sodium chloride solution, at which the first “weak” erythrocytes begin to hemolyze; maximum resistance is the concentration of sodium chloride solution at which all or almost all erythrocytes hemolyzed.Results. The introduction of mezaton led to the development of pronounced hemolysis and hydration of the lungs with the development of their edema and a narrowing of the range of minimum and maximum osmotic resistance of erythrocytes. The introduction of a complex of cholesterol with methyl-β-cyclodextrin after edemogenic exposure led to a decrease in the severity of pulmonary edema, determined by a decrease in the pulmonary coefficient and an increase in the dry residue, and to an increase in the osmotic resistance of erythrocytes with an expansion of the range of their minimum and maximum osmotic resistance.Conclusion. The introduction of a water-soluble complex of cholesterol with methyl-β-cyclodextrin against the background of the development of hemodynamic pulmonary edema significantly reduced the degree of hydration of the lungs, which combined with an increase in the osmotic resistance of erythrocytes.

Angiotensin System Modulations in Spontaneously Hypertensive Rats and Consequences on Erythrocyte Properties; Action of MLN-4760 and Zofenopril

Various pathologies (COVID-19 including) are associated with abnormalities in erythrocyte properties. Hypertension represents an unfavorable condition for erythrocyte quality and is the most prevalent risk factor in COVID-19 patients. ACE2 downregulation that is typical of these patients can further deteriorate cardiovascular health; however, its consequences on erythrocyte properties are not known yet. The aim was to investigate the effect of ACE2 inhibition and the potential beneficial effect of zofenopril on erythrocytes in spontaneously hypertensive rats. ACE2 inhibition induced by MLN-4760 (1 mg/kg/day for 2 weeks) led to deterioration of erythrocyte morphology and osmotic resistance, but plasma markers of oxidative stress, erythrocyte deformability, nitric oxide production and Na,K-ATPase activity were not significantly affected. Zofenopril administration (10 mg/kg/day, initiated after 4-day-lasting ACE2 inhibition) resulted in unexpected increase in angiotensin II plasma levels in both control and ACE-inhibited spontaneously hypertensive rats, but in normalization of osmotic resistance in ACE2-inhibited rats. The overall effect of zofenopril on erythrocyte qualities could be evaluated as beneficial.

Beneficial Effect of Quercetin on Erythrocyte Properties in Type 2 Diabetic Rats

Diabetes mellitus is characterized by tissue oxidative damage and impaired microcirculation, as well as worsened erythrocyte properties. Measurements of erythrocyte deformability together with determination of nitric oxide (NO) production and osmotic resistance were used for the characterization of erythrocyte functionality in lean (control) and obese Zucker diabetic fatty (ZDF) rats of two age categories. Obese ZDF rats correspond to prediabetic (younger) and diabetic (older) animals. As antioxidants were suggested to protect erythrocytes, we also investigated the potential effect of quercetin (20 mg/kg/day for 6 weeks). Erythrocyte deformability was determined by the filtration method and NO production using DAF-2DA fluorescence. For erythrocyte osmotic resistance, we used hemolytic assay. Erythrocyte deformability and NO production deteriorated during aging—both were lower in older ZDF rats than in younger ones. Three-way ANOVA indicates improved erythrocyte deformability after quercetin treatment in older obese ZDF rats only, as it was not modified or deteriorated in both (lean and obese) younger and older lean animals. NO production by erythrocytes increased post treatment in all experimental groups. Our study indicates the potential benefit of quercetin treatment on erythrocyte properties in condition of diabetes mellitus. In addition, our results suggest potential age-dependency of quercetin effects in diabetes that deserve additional research.

A novel gene LbHLH from the halophyte Limonium bicolor enhances salt tolerance via reducing root hair development and enhancing osmotic resistance

Background Identifying genes involved in salt tolerance in the recretohalophyte Limonium bicolor could facilitate the breeding of crops with enhanced salt tolerance. Here we cloned the previously uncharacterized gene LbHLH and explored its role in salt tolerance. Results The 2,067-bp open reading frame of LbHLH encodes a 688-amino-acid protein with a typical helix-loop-helix (HLH) domain. In situ hybridization showed that LbHLH is expressed in salt glands of L. bicolor. LbHLH localizes to the nucleus, and LbHLH is highly expressed during salt gland development and in response to NaCl treatment. To further explore its function, we heterologously expressed LbHLH in Arabidopsis thaliana under the 35S promoter. The overexpression lines showed significantly increased trichome number and reduced root hair number. LbHLH might interact with GLABRA1 to influence trichome and root hair development, as revealed by yeast two-hybrid analysis. The transgenic lines showed higher germination percentages and longer roots than the wild type under NaCl treatment. Analysis of seedlings grown on medium containing sorbitol with the same osmotic pressure as 100 mM NaCl demonstrated that overexpressing LbHLH enhanced osmotic resistance. Conclusion These results indicate that LbHLH enhances salt tolerance by reducing root hair development and enhancing osmotic resistance under NaCl stress.

ESTIMATION OF OSMOTIC RESISTANCE OF SOYBEAN AND LENTIL CULTIVARS AND IMPACT OF BEFORE-SOWING SEED TREATMENT ON DROUGHT RESISTANCE

We estimated the relative drought resistance of different soybean and lentil cultivars and studied impact of before-sowing seed treatment with amino-acid biostimulator on osmotic resistance of plants at the initial stage of ontogenesis. Resistance was determined in solutions with high osmotic potential (water solution of osmotically active agent – mannite of seven atmospheres). We analyzed four soybean and three lentil cultivars. We revealed cultivars having high level of a relative osmotic resistance at the initial stage of plants ontogenesis. As a result of a complex estimation we stated the usage of the biostimulator Biosteam Start positively influenced on soybean seedlings and caused increasing of seeds resistance in drought stress conditions that is very important for the further growth and development of cultural plants.

Un’anemia emolitica da sferocitosi ereditaria

A case of haemolytic anaemia due to spherocytosis in a 3-month-old infant is reported. It is important to remember that post-transfusion blood tests are not reliable and must be repeated 3 months after the transfusion. The erythrocyte osmotic resistance test can give false positive results in the first months of life and must be repeated in the sixth month.

Comparison of Osmotic Resistance, Shape and Transmembrane Potential of Erythrocytes Collected from Healthy and Fed with High Fat-Carbohydrates Diet (HF-CD) Pigs—Protective Effect of Cistus incanus L. Extracts

Long-term high fat-carbohydrates diet (HF-CD) contributes to the formation of irreversible changes in the organism that lead to the emergence of civilization diseases. In this study, the impact of three-month high-fat diet on the physical properties of erythrocytes (RBCs) was studied. Furthermore, the biological activity of Cistus incanus L. extracts, plant known with high pro-health potential, in relation to normal and HF-CD RBCs, was determined. Obtained results have shown that, applied HF-CD modified shape, membrane potential and osmotic resistance of erythrocytes causing changes in membrane lipid composition and the distribution of lipids. The impact of HF-CD on physical properties of RBCs along with atherosclerotic lesions of the artery was visible, despite the lack of statistically significant changes in blood morphology and plasma lipid profile. This suggests that erythrocytes may be good markers of obesity-related diseases. The studies of biological activity of Cistus incanus L. extracts have demonstrated that they may ameliorate the effect of HF-CD on erythrocytes through the membrane-modifying and antioxidant activity.

Inhibition of flippase-like activity by tubulin regulates phosphatidylserine exposure in erythrocytes from hypertensive and diabetic patients

Plasma membrane tubulin is an endogenous regulator of P-ATPases and the unusual accumulation of tubulin in the erythrocyte membrane results in a partial inhibition of some their activities, causing hemorheological disorders like reduced cell deformability and osmotic resistance. These disorders are of particular interest in hypertension and diabetes, where the abnormal increase in membrane tubulin may be related to the disease development. Phosphatidylserine (PS) is more exposed on the membrane of diabetic erythrocytes than in healthy cells. In most cells, PS is transported from the exoplasmic to the cytoplasmic leaflet of the membrane by lipid flippases. Here, we report that PS is more exposed in erythrocytes from both hypertensive and diabetic patients than in healthy erythrocytes, which could be attributed to the inhibition of flippase activity by tubulin. This is supported by: (i) the translocation rate of a fluorescent PS analog in hypertensive and diabetic erythrocytes was slower than in healthy cells, (ii) the pharmacological variation of membrane tubulin in erythrocytes and K562 cells was linked to changes in PS translocation and (iii) the P-ATPase-dependent PS translocation in inside-out vesicles (IOVs) from human erythrocytes was inhibited by tubulin. These results suggest that tubulin regulates flippase activity and hence, the membrane phospholipid asymmetry.