Combined effect of desialated and glycosylated low-density lipoproteins on lipid accumulation in intimal cells of the human aorta in vitro

Institute of Experimental Cardiology, All-Union Cardiologic Scientific Center, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR V. N. Smirnov.) Translated from Byulleten Éksperimental'noi Biologii i Meditsiny, Vol. 112, No. 9, pp. 250–252, September, 1991.     

Resistance of native and circulating modified low-density lipoproteins in human blood to association

The resistance of native and circulating modified low-density lipoproteins from human blood to spontaneous and polyethylene glycol-induced association was studied by recording light transmission fluctuations. Circulating modified low-density lipoproteins were less resistant to association than native low-density lipoproteins. Polyethylene glycol-induced association of low-density lipoproteins was irreversible. Our results suggest that atherogenic activity of circulating modified low-density lipoproteins is associated with their increased predisposition to irreversible association.Translated from Byulleten Eksperimentalnoi Biologii i Meditsiny, Vol. 138, No. 10, pp. 428–431, October, 2004     

Resistance of native and circulating modified low-density lipoproteins in human blood to association

The resistance of native and circulating modified low-density lipoproteins from human blood to spontaneous and polyethylene glycol-induced association was studied by recording light transmission fluctuations. Circulating modified low-density lipoproteins were less resistant to association than native low-density lipoproteins. Polyethylene glycol-induced association of low-density lipoproteins was irreversible. Our results suggest that atherogenic activity of circulating modified low-density lipoproteins is associated with their increased predisposition to irreversible association.Translated from Byulleten Eksperimentalnoi Biologii i Meditsiny, Vol. 138, No. 10, pp. 428–431, October, 2004     

Antigenic differences between apo-B in native and circulating modified low-density lipoproteins

The state of apo-B in native and circulating modified low-density lipoproteins was studied by solid-phase enzyme immunoassay. We studied the interaction of these particles with monoclonal antibodies to apo-B of low-density lipoproteins. Native and circulating modified low-density lipoproteins had different affinity for the studied antigens. Our results illustrate conformational changes in apo-B of circulating modified low-density lipoproteins compared to native low-density lipoproteins. These changes probably contribute to increased accumulation of particles in vascular cells and their transformation into foam cells giving way to atherosclerotic vascular lesions. Translated fromByulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 138, No. 7, pp. 50–53, July, 2004     

Isolation of desialylated low-density lipoproteins from blood of coronary heart disease patients by affinity chromatography

Institute of Experimental Cardiology, All-Union Cardiologic Scientific Center, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR V. N. Smirnov.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 110, No. 12, pp. 606–609, December, 1990.     

Oxidation-induced aggregation of LDL increases their uptake by smooth muscle cells from human aorta

Oxidative modification of human blood LDL induced by Cu²⁺, NaOCl, or 2,2-azobis-(2-aminopropane hydrochloride) was followed by their partial aggregation. Separation of oxidized LDL into aggregates and nonaggregated particles showed that they are characterized by a similar degree of oxidative modification. In contrast to nonaggregated particles, LDL aggregates in the same concentration significantly increased cholesterol content in smooth muscle cells from the intact (no involoved in atherosclerosis) human aortic intima. Our results indicate that atherogenicity of LDL oxidized by various factors is mainly associated with the formation of aggregates, but does not depend on the degree of oxidative modification. __________ Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 143, No. 2, pp. 159–162, February, 2007     

Atherogenic lipoproteins found in the blood of patients with coronary atherosclerosis are desialylated low-density lipoproteins

Institute of Experimental Cardiology, All-Union Cardiologic Scientific Center, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR V. N. Smirnov.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 110, No. 8, pp. 138–140, August, 1990.     

Role of myeloperoxidase-mediated modification of human blood lipoproteins in atherosclerosis development

The mechanism of interaction of hypochlorite and hypobromite formed in myeloperoxidase catalysis with lipids of human blood low-density lipoprotein is described. Both agents react with unsaturated lipids via two mechanisms: molecular (with the formation of mainly chloro-or bromohydrins and lysophospholipids) and free-radical (paralleled by lipid peroxidation). These reactions modify physicochemical properties of low-density lipoproteins and disorder their lipid-transporting function thus initiating early stages of atherosclerosis development. __________ Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Supplement 2, pp. 57–60, April, 2007     

Endothelial cells induce oxidation of low-density lipoproteins

The ability of human umbilical vein endothelial cells to oxidize low-density lipoproteins during a 24-h incubation was assessed from the accumulation of products reacting with 2-thiobarbituric acid and fluorescent products in the incubation medium. It depends on the concentration of lipoproteins and the incubation conditions and increases in the following series: aerobic conditions<ischemia<ischemia+reperfusion. This indicates that ischemia and reperfusion of vascular endothelium may promote parietal oxidation of lowdensity lipoproteins and selective atherosclerotic damage to the vascular wall. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 126, No. 9, pp. 314–317, September, 1998     

High- and low-density lipoproteins stimulate progesterone production in cultured human granulosa cells

Cultured human grannulosa cells are dependent upon gonadotrophinsand exogenous cholesterol for maximal progesterone production.In previous studies low-density lipoproteins (LDLs) have beenconsidered the preferred source of cholesterol, while high-densitylipoproteins (HDLs) seemed rather to reduce progesterone synthesisin these cells. In this study, grandam cells were harvestedfrom 12 women and cultured in medium containing lipoprotein-deficientserum for 3 days. This was followed by 2 days of culture inmedium supplied with LDL or HDL fractions, prepared by sequentialultracentrifugation and affinity chromatography. In the presenceof LH, both lipoprotein fractions enhanced progesterone secretionin a concentration-dependent fashion while basal progesteronesecretion was enhanced to a lesser extent. Progesterone secretionin response to lipoproteins did not differ between cells frompre-ovulatory follicles stimulated with gonadotrophins in vivoand less mature follicles obtained earlier in the menstrualcycle. We conclude that human grandosa cells in vitro can utilizecholesterol carried by HDL as well as LDL for progesterone synthesis.     

Action of lipases on low-density serum lipoproteins

During the action of phospholipase A₂ on low-density serum lipoproteins (LDL) in the presence of serum albumin as adsorbent for low-molecular-weight products of lipolysis a change takes place in the physicochemical properties of the LDL, expressed as a decrease in their flotation coefficients. Lipase hydrolyzes the triglycerides of LDL after preliminary treatment of the latter with phospholipase A₂. Under the influence of lipases the LDL residue becomes insoluble and a cholesterol-rich precipitate is formed. Loss of solubility of lipoproteins following treatment with lipases and proteases may take place in certain states in vivo and may provide the basis for the formation of atheromas, i.e., it may be one of the factors in the pathogenesis of atherosclerosis.Laboratory of Physical Chemistry of Biopolymers, Institute of Biological and Medical Chemistry, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR V. N. Orekhovich.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 84, No. 8, pp. 173–175, August, 1977.