Biomedical subjects

A N Orekhov

Publications and source records attributed to A N Orekhov.

At least 127 records · Page 7Linked to original sources

PubMed1990

[Peritoneal macrophages as a model for the study of the atherogenic potential of the blood serum].

A study was made of the capacity of peritoneal macrophages to demonstrate the atherogenic potential of blood serum. Murine and human macrophages were found to be capable of intracellular accumulation of cholesterol during cultivation with blood sera from patients with coronary atherosclerosis. The data on the capacity to demonstrate blood serum atherogenicity while using peritoneal macrophages do not differ from those obtained previously on the use of smooth muscle cells of the aortal intima and media. The cell culture of the aortal intima and peritoneal macrophages can be used for assessing the atherogenic potential of blood serum.

Adult↗

PubMed1990

[Aggregates of modified low density lipoproteins indicate accumulation of lipids in human aortic intima cells in vitro].

Spontaneous aggregation of glycosylated, desialated, oxidized and malondialdehyde modified low density lipoprotein (LDL) as well as LDL of coronary heart disease patients has been discovered using methods for determination of light transmission fluctuations in suspensions and gel filtration. At the same time; LDL of healthy donors failed to aggregate under conditions of cellular culture. On the other hand, human aortic cells from unaffected intima incubated with modified LDL, but not native LDL of healthy donors, showed a rise in esterified cholesterol levels. There was a strong correlation between the degree of LDL aggregation and intracellular cholesterol ester accumulation (r-0.86, p 0.001, n-21). Removal of aggregates by passing preparations through and 0.1 um filter significantly inhibited the accumulation of cholesterol esters. The obtained data point to the essential, if not decisive, role of LDL aggregation in the processes of lipid accumulation by intimal cells in vitro.

Aorta↗

PubMed1990

[Blood lipophages in patients with ischemic heart disease].

Ninety three individuals were examined and divided into 3 groups: (1) patients with coronary heart disease in the presence of angiographically documented coronary atherosclerosis; (2) those with non-specific aortoarteritis; and (3) subjects without signs of cardiovascular disease. Blood levels of lipid-saturated mononuclear cells were measured by flow cytofluorimetry. The patients (42 (90%) patients of 46) of the first group were found to have higher blood lipophages than those of the other groups, no correlation being established between the plasma content of total cholesterol, high density lipoprotein cholesterol and triglycerides.

Adult↗

PubMed1990

[Desialylated low density lipoproteins--atherogenic lipoproteins occurring in blood of patients with coronary atherosclerosis].

We have recently established that LDL of most patients with coronary atherosclerosis differ from the LDL of most healthy subjects by the ability to cause primary atherosclerotic changes, i.e. the accumulation of intracellular cholesterol in the cells of smooth muscle origin cultured from unaffected intima of human aorta. We assumed that patients LDL is modified lipoprotein differing from native LDL by chemical composition. It has been established in the present study that patients LDL has a substantially lower content of sialic acid as compared with the LDL of healthy subjects. Desialylation of native LDL of healthy subjects with neuraminidase makes them atherogenic, therefore, capable of causing the accumulation of intracellular cholesterol similarly to patients LDL.

Adult↗

PubMed1990

[Low density lipoproteins isolated from the blood of patients with ischemic heart disease induce accumulation of lipids in human aortic intima cells].

Very low density lipoproteins (VLDL), low density lipoproteins (LDL) and high density lipoproteins (HDL) were isolated from the blood of healthy subjects and CHD patients. LDL from the blood of healthy individuals did not raise the intracellular lipid values within 24 h of cultivation. During intracellular lipid values within 24 h of cultivation. During the same incubation period. LDL obtained from the blood of CHD patients caused a 2- to 5-fold rise in cholesterol esters as well as a 1.5- to 3-fold rise in free cholesterol and triglycerides, while the intracellular phospholipid levels remained unchanged. In one of the three cases, the ability to raise the intracellular level of cholesterol esters was demonstrated by VLDL (500 micrograms/ml) derived from CHD patients blood. HDL did not affect the lipid levels in smooth muscle cells cultured from unaffected intima. The obtained data suggests that circulating LDL and, possibly, VLDL in the blood of CHD patients are capable of inducing the accumulation of fat in vascular wall cells.

Adult↗

PubMed1990

[Effects of beta adrenergic blocking agents and calcium antagonists on atherogenic properties of blood serum of patients with ischemic heart disease].

The beta-adrenoblockers anapriline and visken and the calcium antagonist corinfar were studied for effects on the atherogenic properties of the sera from patients with coronary heart disease who took the drugs. The study was performed by using cultured atherosclerotically altered human aortic smooth muscle cells. A single dose of anapriline, 80 mg, and that of visken, 20 mg, were found to give rise to or to enhance atherogenic properties of the patients' sera, while that of corinfar, 20 mg, yielded their antiatherosclerotic properties.

Adult↗

PubMed1989

Lipoprotein aggregation as an essential condition of intracellular lipid accumulation caused by modified low density lipoproteins.

We have tested a hypothesis that aggregates of modified low density lipoproteins (LDL) play the key role in the accumulation of lipids by cells of unaffected aortic intima. It was demonstrated using analysis of relative dispersion of light transmission fluctuations as well as gel filtration on Sepharose CL-2B that LDL modified by oxidation, glycosylation, desialylation and malondialdehyde treatment form aggregates under the conditions of culture. Native LDL failed to aggregate under the same conditions. It was demonstrated that modified LDL, unlike native LDL, bring about a 2- to 3-fold rise in cholesteryl ester levels of cultured cells. Moreover, direct and strong correlation (r = 0.86) was observed between the degree of lipoprotein aggregation and the amount of cholesteryl esters accumulated. Removal of modified LDL aggregates by filtration through a 0.1 micron filter or gel filtration completely prevented the intracellular accumulation of cholesteryl esters. These findings indicate that LDL aggregates play an essential, if not the decisive, role in the intracellular accumulation of lipids in vitro.

Aorta↗

PubMed1989

Modification of low density lipoprotein by desialylation causes lipid accumulation in cultured cells: discovery of desialylated lipoprotein with altered cellular metabolism in the blood of atherosclerotic patients.

Low density lipoprotein (LDL) isolated from the blood of healthy donors was partially desialylated by incubating the lipoprotein with sialidase (neuraminidase). The addition of LDL treated with neuraminidase to cultured human aortic intimal cells of smooth muscle origin caused a substantial increase in intracellular cholesteryl esters, free cholesterol and triglycerides. Cultured cells took up and degraded desialylated LDL much more effectively than untreated (native) LDL. LDL were also isolated from an atherogenic blood plasma of patients with coronary artery disease, i.e. the plasma capable of inducing the accumulation of lipids in cultured cells. Patients' LDL, similarly to the mother plasma, were atherogenic, i.e. stimulated the accumulation of intracellular lipids. LDL isolated from nonatherogenic plasma of healthy donors proved to be nonatherogenic. Atherogenic patients' LDL had a 2- to 5-fold lower level of sialic acid as compared with nonatherogenic LDL of healthy donors. The uptake and degradation of atherogenic patients' LDL were much more effective than in the case of nonatherogenic LDL of healthy donors. We assume that atherogenic properties of LDL obtained from patients' blood plasma are explained exactly by a low sialic acid content.

Adult↗

PubMed1989

Use of lipophilic fluorescent probes for the isolation of hybrid cells in flow cytometry.

Flow cytometry was used for the isolation of hybrid cells immediately after fusion. Precursor cells were stained by two lipophilic fluorescent probes: perylenoyl-labeled triglyceride (perylenoyl-TG, green fluorescence, 520 nm) and rhomdaminyl-labeled triglyceride (rhodaminyl-TG, red fluorescence, greater than 580 nm). Since the maximum emission of perylenoyl-TG coincides with the maximum absorbance of rhodaminyl-TG, the two fluorescent dyes form an effective donor-acceptor pair. Cells stained by perylenoyl-TG (0.25-1 microgram/ml) at the excitation wavelength of 457 nm displayed high intensity of fluorescence in the green region (520 nm), and low intensity of fluorescence in the red region (greater than 580 nm). Using the same conditions, cells that were stained by rhodaminyl-TG displayed a low intensity of fluorescence in both regions. When cells were simultaneously labeled by perylenoyl-TG and rhodaminyl-TG (used in a concentration ratio of 1:10, respectively) essentially total energy transfer was observed, and the cells exhibited a high intensity of red fluorescence. After the fusion of cells which had been separated stained by perylenoyl-TG and rhodaminyl-TG, the hybrid cells containing the two fluorescent probes had a high intensity of red fluorescence. Resonance exitation energy transfer between the two fluorescent dyes permits effective sorting of hybrid cells by flow cytofluorometry.

Cell Fusion↗

PubMed1989

Neutral glycolipids of atherosclerotic plaques and unaffected human aorta tissue.

The composition, structure and localization of neutral glycosphingolipids of human aorta taken from subjects who had died after myocardial infarction were studied. Individual glycosphingolipids were purified by high-performance liquid chromatography and were characterized on the basis of their chromatographic mobility, carbohydrate composition, methylation analysis and by 1H-NMR spectroscopy. The main aortic glycosphingolipids were identified as glucosylceramide, lactosylceramide, globotriaosylceramide and globotetraosylceramide. Significant differences in the neutral glycosphingolipid composition of intima and media were detected. The neutral glycosphingolipid profile of medial plaques resembled that of unaffected media; however, significant differences were detected between intimal plaques and unaffected intima. Whereas the latter contained trihexosylceramide and globoside as the only neutral glycolipids, the intimal plaque glycolipids consisted mainly of glucosylceramide and also contained appreciable amounts of lactosylceramide which were completely absent in the unaffected intima. In comparison to intimal plaques, unaffected intima is characterized by a much higher content of cerebrosides terminating by beta-galactosyl residues which are known to interact with growth factors and other external stimuli. It thus seems possible that the proliferative activity of smooth muscle cells in atherosclerotic diseases is to some extent associated with their neutral glycolipid profile.

Adult↗

PubMed1989

Low-density lipoproteins isolated from the blood of patients with coronary heart disease induce the accumulation of lipids in human aortic cells.

Smooth muscle cells cultured from the intima of unaffected human aorta accumulate lipids during incubation with the blood serum of patients with coronary heart disease (CHD). Blood sera of most healthy subjects fail to induce the deposition of lipids in cultured cells. Very-low-density lipoproteins (VLDL), low-density lipoproteins (LDL), and high-density lipoproteins of two subclasses (HDL2 and HDL3) were isolated from the blood of healthy subjects and CHD patients. LDL from the blood of healthy individuals did not raise intracellular lipid levels within 24 hr of cultivation (the maximal concentration used, 1000 micrograms/ml). During the same incubation period, LDL obtained from the blood of CHD patients (200 to 1000 micrograms/ml) caused a 2- to 5-fold rise in cholesteryl esters as well as a 1.5- to 3-fold rise in free cholesterol and triglycerides, whereas intracellular phospholipid levels remained unchanged. There was a direct correlation (r = 0.95) between cholesterol accumulation in the cells incubated with whole sera of CHD patients and cholesterol level in the cells incubated with LDL isolated from these sera. In one of the three cases, the ability to raise the intracellular level of cholesteryl esters was demonstrated by VLDL (500 micrograms/ml) derived from CHD patients' blood. HDL2 and HDL3 did not affect lipid levels in smooth muscle cells cultured from unaffected intima. HDL3 from the blood of CHD patients and healthy subjects (50 to 250 micrograms/ml) reduced cholesteryl ester levels in cells cultured from atherosclerotic plaques 1.5- to 2-fold. HDL2 also decreased the content of cholesteryl esters in plaque cells, though less effectively than HDL3. The data obtained suggest that circulating LDL and, possibly, VLDL in the blood of CHD patients are capable of inducing the accumulation of fat in vascular wall cells.

Adult↗

PubMed1989

Insolubilization of low density lipoprotein induces cholesterol accumulation in cultured subendothelial cells of human aorta.

Primary cultures of typical and modified smooth muscle cells isolated from the intima of human aorta were used to study the mechanism whereby low density lipoprotein (LDL) induces accumulation of intracellular cholesterol. Incubation of intimal cells with native LDL obtained from human plasma did not lead to deposition of total cholesterol. LDL added to the cultures simultaneously with hyaluronic acid, heparin, chondroitin sulfate, fibronectin, and mouse monoclonal antibody against LDL also failed to alter the cellular cholesterol. On the other hand, 24-h incubation of the cells with LDL in the presence of dextran sulfate, gelatin, particles of aortic elastin, particles of collagenase-resistant aortic matrix, goat polyclonal antibodies against LDL or latex beads caused a significant (1.5-7-fold) increase in total cholesterol. The compounds which stimulated cholesterol deposition are able to form precipitating complexes with LDL. On the contrary, the agents which failed to induce cholesterol accumulation were unable to insolubilize LDL. A direct correlation (r = 0.927) was found between the cholesterol content of the insoluble complex and the increment of cholesterol in the cultured cells. To find out whether LDL plays a specific role in the deposition of intracellular cholesterol, very low density lipoproteins and high density lipoproteins were used. These lipoproteins stimulated the accumulation of intracellular cholesterol in the presence of agents capable of forming insoluble associates with them. Our data suggest that insolubilization of lipoproteins is a key event in the LDL-mediated accumulation of intracellular cholesterol induced by various agents.

Aortic Diseases↗

PubMed1989

Ganglioside content and composition of cells from normal and atherosclerotic human aorta.

The ganglioside content and composition of cells obtained by enzyme digestion of 2 layers of human aortic intima were investigated. Five gangliosides were identified in cells isolated from the external musculo-elastic intimal layer adjacent to the media: GM3, GM1, GD3, GD1a, and GT1b. The same gangliosides plus ganglioside Gx, the chromatographic mobility of which corresponded to the mobility of ganglioside GD1b from human brain, were found in cells from the internal elastic-hyperplastic intimal layer adjacent to the vessel lumen. In both layers, the major cellular ganglioside was GM3 which represented 60% of the total cellular ganglioside content. The ganglioside content was lower in cells obtained from fatty streaks compared to cells isolated from unaffected intima. The amount of di- and trisialogangliosides in atherosclerotic plaque cells was lower, and that of monosialogangliosides higher than in cells isolated from unaffected intima. The amount of GM3 was mainly responsible for the difference in the total ganglioside content of cells obtained from different lesion types. On the whole, cells from fatty streaks contained smaller amounts of total gangliosides, whereas cells from plaques had greater total ganglioside content, than cells from unaffected intima.

Adult↗

PubMed1989

Peritoneal macrophages: a model for detecting atherogenic potential in patients' blood serum.

Human and mouse peritoneal macrophages cultured in the presence of the blood serum of patients with documented coronary heart disease showed a 2- to 3-fold rise in levels of intracellular cholesterol ester and a 1.5- to 2-fold increase in those of free cholesterol and triglycerides. This effect was observed in 83% of cases, whereas the serum of healthy subjects induced the accumulation of lipids in macrophages only in 28% of cases. These data accord with previously published observations obtained on smooth muscle cells of human aortic intima. A direct correlation was found between the accumulation of cholesterol in macrophages and in cultured smooth muscle cells of human aortic intima. The accumulation of lipids in macrophages was dose dependent and increased with time. It is assumed that a culture of peritoneal macrophages may serve as a model for identifying an atherogenic potential of patients' blood serum.

Adult↗

PubMed1989

[Cholesterol-containing circulating immune complexes--a component of the blood serum in patients with ischemic heart disease that determines its atherogenic properties].

In most patients with coronary heart disease (CHD) and angiographically documented stenosed 1-3 coronary arteries, serum contained cholesterol (C) in the circulating immune complexes (CIC), cholesterol levels in these complexes being directly related to serum atherogenicity, i.e. to their ability to cause a 2-5-fold accumulation of lipids in cultured smooth muscle cells (SMC) of the uninvolved human aortic intima (r = 0.91). Removal of IgG and IgM from the patients' sera led to a 75 and 37% decrease, respectively, in their atherogenic properties displayed in cultured SMC. Much more decrease in the atherogenic potential of the sera was seen in 2.5% polyethylene glycol-induced precipitation of CIC. At the same time, incubation of human aortic intimal SMC with CIC isolated from the atherogenic sera from CHD patients caused a 1.5-3-fold increase in intracellular C levels. It was suggested that CIC cholesterol was a determinant of atherogenicity of the sera from patients with coronary atherosclerosis.

Antigen-Antibody Complex↗

PubMed1989

[The content of cyclic nucleotides in an organ culture of normal and atherosclerosis-affected human aorta].

Cyclic AMP and cyclic GMP content was measured in intima media of unaffected and atherosclerotic areas of human aorta in a short-term organ culture. It was demonstrated that during short-term cultivation the content of both cyclic nucleotides in tissues is constant. The cyclic AMP content in fatty streaks and atherosclerotic plaques is significantly (2 to 7-fold) lower than in unaffected intima. The cyclic GMP level in atherosclerotic lesions is 1.5 to 3-fold higher than in normal. The content of both cyclic nucleotides in the media underlying fatty streaks and atherosclerotic plaques is the same as in the normal tissue. The obtained data indicate serious disorders in the system of cyclic nucleotides during atherosclerosis.

Adult↗

PubMed1989

[Atherogenic properties of beta adrenergic blockaders evident on vascular wall cells].

In cultured human cells, beta-adrenoblockers such as propranolol, alprenolol, metoprolol, atenolol, pindolol, and thymolol, as well as sera from patients with coronary heart disease were examined for atherogenic activity following a single administration of propranolol (80 mg) and pindolol (10 mg). Addition of the beta-adrenoblockers to the cell culture was demonstrated to enhance cellular total cholesterol levels and to stimulation their proliferation. Propranolol and pindolol given in a single dose was found to result in the appearance of atherogenic properties of the patients' sera.

Adrenergic beta-Antagonists↗

PubMed1989

[Effect of medicinal leech preparations on indicators of atherogenesis].

Medicinal leech salivary gland secretion, administered intravenously to rats on an atherogenic diet, reduces fibrinogen level and plasma heparin tolerance and diminishes lipid deposits in the intima of large vessels. Long-term chronic oral administration of dried medicinal leech powder to rats, kept on an atherogenic diet, reduces the area of local edema in the intima of large vessels, although blood lipid composition, fibrinogen level and plasma heparin tolerance remain basically unchanged, as compared to respective values in the control animals. The salivary gland secretion reduces the 3H-thymidine incorporation into the human atherosclerotic intimal cell culture.

Administration, Oral↗