[Characterisation of circulating microRNA-21 levels in patients with hypertrophic cardiomyopathy].

AIM: To study the levels of circulating microRNA-21 in patients with hypertrophic cardiomyopathy (HCM) of different ages. MATERIALS AND METHODS: The study included 49 patients with HCM. The proportion of females was 55.1%, males 44.9%. The average age was 50 [32; 65] (from 19 to 86 years). The control group for microRNA-21 included 44 healthy individuals, respectively, matched by the age and sex with the studied patients. Patients was made in accordance with the recommendations of the European society of cardiology. Plasma microRNA expression was determined by PCR with reverse transcription and real-time detection of results. The relative level of gene expression was calculated in accordance with the standard procedure 2-Ct. RESULTS: Septal wall thickness at end diastole has a significant negative correlation with age in patients with HCM (r=-0.56; р0.001). PWTd (posterior wall thickness at end diastole) has a significant positive correlation with age in patients with HCM (r=0.67, р0.001). The level of circulating microRNA-21 in plasma is higher in patients with HCM compared to healthy individuals (5.28 [2.64; 13.96] and 0.84 [0.55; 1.23], respectively; p0.001). Significantly higher levels of microRNA-21 were found in young patients aged from 19 to 45 years with the symptomatic course of HCM (36.76 [5.66; 42.22]) compared to patients with asymptomatic course 45 years of age (2.81 [1.45; 5.28]; p0.002) and symptomatic patients 45 years (3.88 [2.16; 8.63]; p0.002).) The calculated risk of SCD was significantly higher in young symptomatic patients with HCM (6.01 [3.64; 9.67]) compared to patients with asymptomatic course 45 years (2.41 [1.21; 3.89]; p0.001) and symptomatic patients 45 years (2.56 [1.67; 4.41]; p0.001). CONCLUSION: The level of circulating microRNA-21 is significantly in patients with HCM compared to control group. The maximum level of circulating microRNA-21 was detected in patients with symptomatic course of HCM at the age of 45 years.

Interaction of chitosans and their N-acylated derivatives with lipopolysaccharide of gram-negative bacteria.

The interactions of lipopolysaccharide (LPS) with the natural polycation chitosan and its derivatives--high molecular weight chitosans (80 kD) with different degree of acetylation, low molecular weight chitosan (15 kD), acylated oligochitosan (5.5 kD) and chitooligosaccharides (biose, triose, and tetraose)--were studied using ligand-enzyme solid-phase assay. The LPS-binding activity of chitosans (80 kD) decreased with increase in acetylation degree. Affinity of LPS interaction with chitosans increased after introduction of a fatty acid residue at the reducing end of chitosan. Activity of N-monoacylated chitooligosaccharides decreased in the order: oligochitosan --> tetra- > tri- --> disaccharides. The three-dimensional structures of complexes of R-LPS and chitosans with different degree of acetylation, chitooligosaccharides, and their N-monoacylated derivatives were generated by molecular modeling. The number of bonds stabilizing the complexes and the energy of LPS binding with chitosans decreased with increase in acetate group content in chitosans and resulted in changing of binding sites. It was shown that binding sites of chitooligosaccharides on R-LPS overlapped and chitooligosaccharide binding energies increased with increase in number of monosaccharide residues in chitosan molecules. The input of the hydrophobic fragment in complex formation energy is most prominent for complexes in water phase and is due to the hydrophobic interaction of chitooligosaccharide acyl fragment with fatty acid residues of LPS.

Determination of binding constants of lipopolysaccharides of different structure with chitosan.

The interaction of endotoxins--lipopolysaccharides (LPS) different in degree of the O-specific chain polymerization--with 20- and 130-kD chitosan was studied using the competitive binding of LPS with the complex of chitosan-anionic dye (tropaeolin 000-2) and the direct binding of (125)I-labeled LPS with chitosan immobilized on Sepharose 4B. The interaction of 20-kD chitosan with LPS was non-cooperative, and immobilization of the polycation on Sepharose resulted in its binding to (125)I-labeled LPS with a positive cooperativity. The interaction of LPS possessing a long O-specific chain with 130-kD chitosan was characterized by negative cooperativity. Binding constants of LPS with the polycation and the number of binding sites per amino group of chitosan were determined. The interaction affinity and stoichiometry of the LPS-chitosan complexes significantly depend on the LPS structure and concentration in the reaction mixture. The increase in the length of carbohydrate chains of LPS results in increase in the binding constants and decrease in the bound endotoxin amount.

The effect of temperature on the interaction of Yersinia pseudotuberculosis lipopolysaccharide with chitosan.

The mechanism of binding of lipopolysaccharide (LPS) from Yersinia pseudotuberculosis to low-molecular-weight chitosan was investigated using sedimentation analysis, centrifugation in glycerol and percoll density gradients, and isopicnic centrifugation in cesium chloride. The LPS interaction with chitosan was shown to be a multistage process that depended on time and reaction temperature. A stable LPS-chitosan complex could be formed only after preliminary incubation of the initial components at an elevated temperature (37 degrees C). This temperature caused the LPS dissociation and promoted its binding to chitosan. The LPS binding to chitosan results in further dissociation of the endotoxin and formation of the complex with a molecular weight that is tens of times less than the initial molecular weight of LPS. The obtained complex remained stable in solutions of high ionic strength.