Development of a model system for evaluation of human endothelial cell proliferation in vitro: possible clinical applications.

A system for evaluation of the ability of human blood serum to affect endothelial cell proliferation was developed and tested. The system based on incorporation of (3)H-thymidine into DNA was used to analyze the effects of hormone replacement therapy on endothelial repair and angiogenesis. Blood serum from 12 menopausal women less effectively activated endothelial proliferation compared to control donor serum.

Glucocorticoids stimulate cholesteryl ester formation in human smooth muscle cells.

The aim of the present study was to investigate the effect of synthetic glucocorticoid dexamethasone (Dex) on cholesterol esterification in cultured human smooth muscle cells (SMC). In labeled SMC, Dex stimulated the esterification of [3H]cholesterol in a dose-dependent manner. This effect was specific for glucocorticoid hormones and could be inhibited by cycloheximide (3 ng/mL), actinomycin D (10(-5) mol/L), and the specific glucocorticoid antagonist RU 486 (10(-8) mol/L).

Effect of VLDL on the inhibition of arachidonic acid transformation by dexamethasone in cultured smooth muscle cells.

Very-low-density lipoproteins (VLDL) induce a dose-dependent reduction (up to 55%) in the number of specific binding sites and about a 2-fold increase in binding affinity for [3H]dexamethasone in human and rat smooth muscle cells (SMC). Maximal effect of VLDL was achieved within 3-5 h at a lipoprotein concentration 60 micrograms protein/ml. Lipoprotein-mediated reduction in the number of [3H]dexamethasone binding sites resulted in partial loss of cellular sensitivity to hormone action: dexamethasone (1 x 10(-6) M) inhibited the transformation of [14C]arachidonic acid (AA) into metabolites to a lesser extent in SMC preincubated with VLDL (11.

Reduced sensitivity of cultured skin fibroblasts from familial hypercholesterolemic patients to glucocorticoids.

Cultured human skin fibroblasts, obtained from patients with homozygous familial hypercholesterolemia (FH), exhibited cholesterol synthesis that was 2.5-3-fold more intensive than in cells from healthy donors (normal cells). The study of the glucocorticoid [3H]-dexamethasone specific binding (glucocorticoid receptors, GcR) to the cells showed reduced number of binding sites (8 x 10(3) vs 120 x 10(3) binding sites/cell) and reduced Kd value (5.

[Regulation of intracellular cholesterol synthesis in hypercholesterolemia by glucocorticoids].

The rate of endogenous cholesterol synthesis in blood lymphocytes and skin fibroblasts from patients with type IIa hyperlipidemia was found to be increased in comparison with healthy donors. The cells of hyperlipidemic patients had lowered levels of glucocorticoid receptors concomitantly with a partial loss of their sensitivity to glucocorticoids. In fibroblasts from patients with hereditary hypercholesteremia of homozygous type the number of glucocorticoid receptors did not exceed 10% of their content in normal cells.

[Endocrine status changes in children with bronchial asthma].

A study was made of adrenocortical function by measuring blood plasma cortisol concentration and amount of glucocorticoid receptors in lymphocytes as well as thyroid function by measuring blood plasma triidothyronine and thyroxine concentration in 58 bronchial asthma children aged 1 to 14 years. The authors revealed alterations in the functional activity of the indicated endocrine glands depending on the intensity of bronchial patency disorders and the nature of the therapeutic measures carried out.

Number of glucocorticoid receptors in lymphocytes and their sensitivity to hormone action.

The study demonstrated a decreased level of glucocorticoid receptors (GR) in peripheral blood lymphocytes from hypercholesterolemic subjects, and an elevated level in patients with acute myocardial infarction. In the lymphocytes with a high GR number, dexamethasone inhibited [3H]-thymidine and [3H]-acetate incorporation into DNA and cholesterol, respectively, in the same manner as in the control cells. On the other hand, a decreased GR number resulted in a less efficient dexamethasone inhibition of the incorporation of labeled compounds.

[Reduced cell sensitivity to glucocorticoid hormones in hypercholesterolemia].

The number of 3H-dexamethasone binding sites in lymphocytes of subjects with hypercholesterolemia (HCS) was found to be decreased as compared to the receptor level in normolipidemic patients (N). In HCS-lymphocytes, the dexamethasone-induced inhibition of 3H-thymidine and 14C-acetate incorporation was less pronounced (by 20% and 22%, respectively) than in control cells, which is suggestive of the decreased sensitivity of HCS-lymphocytes to the hormone. An addition of 5-25% HCS blood sera to human skin fibroblast cultures caused a 10-50% decrease in the number of 3H-dexamethasone binding sites and diminished the Kd values 2-3 times.

Reduced sensitivity of peripheral cells to glucocorticoids in hypercholesterolemia.

It has been found that lymphocytes of hypercholesterolemic (HCh) subjects are characterized by a reduced number of glucocorticoid receptors (GcR) as compared with the cells of normolipidemics (N). Addition of HCh-sera or very low density lipoproteins, or low density lipoproteins isolated both from HCh-sera and N-sera to cultured human skin fibroblasts brought about a fall in the number of GcR in the cells. High density lipoproteins had no effect on GcR level.

[Mechanism of activating the lymphocyte glucocorticoid receptor in acute myocardial infarct].

Dose-dependent increase in content of highly specific binding sites for glucocorticoids (receptors), but without alteration in their affinity to the hormone, was observed after incubation during 2 hrs of healthy donor lymphocytes with blood serum of patients with acute myocardial infarction. The similar effects exhibited protein extracts of necrotized and normal parts of human myocardium (heart antigens) as well as the autologous blood serum and human blood serum albumin treated with UV-irradiation. Number of receptors was not altered in human skin fibroblasts incubated both with the patients blood serum and with the UV-treated blood serum.

[Changes in the characteristics of glucocorticoid hormone binding in human peripheral blood lymphocytes during myocardial infarct].

Competitive binding was used to determine the number of binding sites to glucocorticoid hormones in peripheral blood leukocytes of normal subjects, patients with unstable angina pectoris and patients with myocardial infarction. A sharp (2-3-fold) increase in the number of binding sites was observed in patients with myocardial infarction during the first 24 hours after the onset of the disease.