Search

To investigate interaction of atherogenic low-density lipoproteins (LDL) with erythrocytic membrane, the content of lipid components in blood cells and serum LDL was studied in human in norm (donors) and in 12 species of vertebrates (the mammals non-predisposed to atherosclerosis - birds and fish). Lipid composition of blood cells and LDL was analyzed also in patients with pathologies: ischemic heart disease (IHD), bronchial asthma (BA), and chronic obstructive bronchitis (COB), and in 2 species of mammals predisposed to atherosclerosis, in whose blood LDL predominates. The content of lipids in cells and LDL of the studied vertebrates has been found to depend on their taxonomy and the clear trends both to an increase of the cholesterol content and to a decrease if the phosphatidylcholine level in patients, particu- larly with IHD, and on a rise of the ratio of the content of the more saturated sphingomyelin and cholesterol to the less saturated phosphatidylcholine from the lower to the higher organisms, including humans (donors). The highest levels of free cholesterol in blood cells, of total cholesterol in LDL, and of ration of the cholesterol/phosphatidylcholine content have been revealed in patients, especially with 1HB, and in the mammals predisposed to atherosclerosis, i. e., in representatives with predominance of blood LDL, unlike donors and the mammals resistant to atherosclerosis. The highest parameters of lipid components were determined in cells and LDL inhuman with IHD. The lipid LDL composition affects directly the composition and ratio of lipids in blood cells.

Lipid composition of blood serum and total lipids of low density lipoproteins (LDL) and high density lipoproteins (HDL2 and HDL3) were studied in human (donors, patients with ischemic heart disease, bronchial asthma, chronic obstructive bronchitis, as well as with a combined pathology), in mammals predisposed to atherosclerosis (pig, rabbit) and resistant to atherosclerosis (rat, mink, Arctic fox), in birds (hen, pigeon), in teleost fish (white fish, pikeperch, pike, bream, burbot) and cartilaginous fish (sturgeon, housen). It has been established that the most enriched in lipids is the blood serum of animals, particularly of cartilaginous fish. Twice lower is the lipid content in blood serum of donors than of animals. However, in the vascular, bronchial-pulmonary, and combined human pathologies the lipid level rises statistically significantly. In human and in animals predisposed to atherosclerosis the main mass of lipid is located in LDL, whereas in animals resistant to this disease--in HDL. The ratio of the human lipid content in LDL/HDL increases from 1.4 (in donors) to 2.7 in pathological states--in ischemic heart disease and its combination with chronic obstructive disease. In animals, a decrease of this ratio is noted from 1.0 to 0.2 in cartilaginous fish. By the example of one taxon (fish) there is established a regularity that indicates that evolution of lipoproteins occurred with an increase of the lipid amount in the "younger" LDL and with a decrease of concentration of the "colder" HDL.

Using precipitation method, low-density (LDL) and high-density (HDL2 and HDL3) lipoproteins were isolated from blood serum of human (donors, patients with ischemic heart) diseases--IHD, with bronchial asthma--BA, with chronic obstructive bronchitis--COB), of mammals predisposed (pig, rabbit) and resistant (rat, mink, Arctic fox) to atherosclerosis, of birds (hen, pigeon), of bony fish (trout, white-fish, pike-perch, pike, bream, burbot), and of cartilaginous fish (sturgeon, white sturgeon). From each lipoprotein group, lipids were extracted, separated by thin-layer chromatography, and analyzed quantitatively by the spectrophotometric method. In phosphatidylcholine and HDL2 cholesterol esters, bound fatty acids (FA) were determined by the method of gas-liquid chromatography. The main amount of total cholesterol has been established to be concentrated in human LDL, especially in the cases of IHD, and in LDL in mammals predisposed to atherosclerosis. In mammals resistant to atherosclerosis and in fish the almost entire cholesterol was revealed in HDL. The phospholipid content in HDL was lower in patients with pathologies and in mammals predisposed to atherosclerosis, while the highest content--in fish and mammals resistant to atherosclerosis. In homoiothermal animals and in human the main FA amount in HDL was represented by the omega6-series. Acids of the omega3-series amounted to a negligible percentage, especially in IHD. On the contrary, the HDL FA composition of poikilothermal animals (fish) had a very high content of polyunsaturated FA of the omega3-series. A conclusion is made that composition of lipid components in animal lipoproteins by the example of several studied species and of human has a non-stable character and is submitted to changes. Their most pronounced modifications with a negative trend took place in human LDL and HDL in IHD.

Methods of thin-layer, gas-liquid, and liquid chromatography were applied to the study of the effect of various concentrations of aluminum and iron salts on the contents of phospholipids, cholesterol, and fatty acids in the aquatic invertebrate Hydropsyche contubernalis L. (Trichoptera). It was found that the effect of the metals under study on lipid contents in living organisms depended on the composition of the aqueous medium and concentrations of the metals. Aluminum and iron altered the value of the cholesterol-to-phospholipid molar ratio. In the absence of lethal effects, this was indicative of attempts to switch adaptational biochemical mechanisms to stabilize cellular structures.

We studied lipid composition of low- and high-density lipoproteins from serum of female rainbow trout Salmo irideus L. and whitefish Coregonus lavaretus L. Phospholipids are main lipids in all fractions and phosphatidylcholine is the major phospholipid. Species specificity of lipid fractions are due to ecological conditions typical for the studied fish species, a nearly domesticated rainbow trout and whitefish, a component of natural ichthyofauna. Serum of the studied fish species contains lipoprotein groups specific for other animals; however, high-density lipoproteins predominate in fish.

The influence of low pH (5.0 and 4.0) on lipid metabolism of caddisworms Hydropsyche contubernalis L. (Trichoptera) was studied in 48 h toxicity experiments. The results were correlated with lipid composition of caddisworms directly isolated from natural water. Phospholipids, cholesterol, mono-, di-, triacylglycerols, and fatty acids were detected by thin-layer and liquid chromatography. Minimal environmental changes were shown to initiate the biochemical adaptation mechanisms strengthening the cellular membranes through their condensation due to additional phospholipid and cholesterol synthesis. In the natural medium the adaptation processes are more active than in the artificial medium. More serious changes, such as pH decrease to 4.0, suppress the adaptation processes in the first medium and terminated them in the second one.

The effects on the lipid status of developing embryos of a disturbed natural ratio of cations in water as a result of the pollution of water bodies by waste with a high potassium content (130-140 mg/I) were studied in the laboratory. The results obtained confirm the indication of reduced lipid synthesis and altered formation of phospholipids in embryos developing in a medium with a disturbed natural ratio of cations. In addition, the lysophospholipid fraction increased in these embryos, which indicates activation of phospholipid hydrolysis. It was also found that changes in the salt regime lead to a decreased content of cholesterol, the main membrane thickener. It was proposed that the changes discovered lead to disturbed stability and permeability of the membranes of fish eggs, with the subsequent death of embryos.

It has been shown that the content of individual lipids and their ratio to phospholipids in blood lipoproteins of various density markedly differs in different classes of vertebrates, these differences being especially distinct for low density lipoproteins (LDL), as compared with high density lipoproteins (HDL2 and HDL3). Specifically, the total concentration of phospholipids and triacylglycerols in LDLs decreases in a sequence from fish to mammals, while the content of cholesterol esters increases, the proportion of cholesterol, cholesterol esters and triacylglycerols markedly increasing when calculated for phospholipids. Hence, it seems that the cholesterol coefficient of atherogenicity increases in the course of evolution of vertebrates. The HDL phosphatidylcholines contain much less fatty acid radicals with the odd number of carbon atoms than the cholesterol esters, this ratio being less distinct in fish as compared with birds or mammals. As a rule, domesticated animals have a higher cholesterol coefficient of atherogenicity than the wild ones, i.e., they are more susceptible to atherosclerosis.

Complete lipid composition was estimated in both atherogenic lipoproteins of low density (LDL) and in antiatherogenic lipoproteins of high density HDL2 and HDL3 subfractions isolated from blood serum of 25 healthy volunteers and of 40 patients with bronchial asthma; ultracentrifugation, thin-layer chromatography and spectrophotometry were used in experiments. Development of bronchial asthma was accompanied by district impairments in the spectrum of structure containing lipids especially due to decrease in content of lecithin in LDL and HDL2, of phosphatidic acid in LDL and in the HDL fractions; both these lipids are main constituents of the surfactant system in the respiratory tract. Besides, metabolism of cholesterol was also impaired, while cholesterol esters were redistributed between various lipoproteins, thus total cholesterol was increased in LDL and HDL3; however, cholesterol coefficient in the patients maintained within the same limits as compared with that of donors.

Fatty acid composition of lecithin and cholesterol esters was studied in high density lipoproteins obtained from blood serum of 20 male volunteers, 10 pigs, 10 rats and 30 burbots (Lota lota); the study was carried out using isolation (precipitation) of the lipoproteins, thin-layer chromatography of lipoproteins and gas liquid chromatography of fatty acids. The findings suggest that the fatty acid composition of the preparations studied may serve as a more exact index of lipid metabolism than the serum levels of individual lipoproteins.

A method for separation of human blood serum lipoproteins into 3 fractions (low- and high-density lipoproteins, subfractions 2 and 3) is described in detail. The method may be used to rapidly obtain information on the status of lipid metabolism in humans and animals. The results of lipid composition analysis of individual lipoprotein fractions are presented. These data were obtained in a series of experiments and EC-1052 computer-processed with the use of a COM applied program pack. Basing on the results of investigation of individual fractions' lipid composition, the authors make a conclusion on the characteristic features of each fraction, which in future may be helpful in the diagnosis of pathologic process and in detection of lipid metabolism disorders in the body.