concanavalin-a and Hypercholesterolemia

The use of statins has shown several anti-inflammatory actions, including modulatory effects on T cells in vitro. Since the effects on human T cells in vivo are less clarified, our aim was to investigate the effects of simvastatin on human T cells in vivo and ex vivo.. A randomized, double-blind, placebo-controlled study design was applied. Eighty volunteers with mild to moderate hypercholesterolemia received either simvastatin 40 mg or placebo for 6 weeks. The serum levels of C-reactive protein (CRP) were significantly reduced by simvastatin. The proportions of CD4+ and CD8+ T cell subsets expressing early (CD25) or late (HLA-DR) activation markers, as assessed by flow cytometry, were not changed by simvastatin. However, simvastatin tended to increase the density of HLA-DR and L-selectin per CD8+ T cell. The T helper(h)1/Th2 response was evaluated by stimulatory assays followed by intra-cellular staining of interferon-gamma and interleukin-4. Simvastatin treatment did not affect the Th1 response but the results indicated a potential to suppress Th2.. Simvastatin treatment resulted in a few discrete changes as regards peripheral T cells. However, the findings do not provide evidence that simvastatin-induced anti-inflammatory actions are related to any significant modulatory effects on human T cells in clinically healthy men with hypercholesterolemia.

Topics: Adult; Apolipoproteins; C-Reactive Protein; Concanavalin A; Double-Blind Method; Enterotoxins; HLA-DR Antigens; Humans; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Hypercholesterolemia; Interleukin-2 Receptor alpha Subunit; L-Selectin; Lipids; Male; Middle Aged; Simvastatin; T-Lymphocyte Subsets; T-Lymphocytes

Porphyromonas gingivalis, a major periodontal pathogen, has been reported to be involved in atherogenesis. In order to further understand this pathogen's link with systemic inflammation and vascular disease, we investigated its influence on murine monocytes and macrophages from three different sources.. Concanavalin A-elicited peritoneal macrophages, peripheral blood monocyte-derived macrophages and WEHI 274.1 monocytes were infected with either P. gingivalis 381 or its non-invasive fimbriae-deficient mutant, DPG3.. Infection with P. gingivalis 381 markedly induced monocyte migration and significantly enhanced production of the pro-inflammatory cytokines, tumor necrosis factor-alpha and interleukin-6. Consistent with a role for this pathogen's major fimbriae and/or its invasive capacity, infection with DPG3 had a minimal effect on both monocyte attraction and pro-inflammatory cytokine production.. Since monocyte recruitment and activation are important steps in the development of vascular inflammation and atherosclerosis, these results suggest that P. gingivalis infection may be involved in these processes.

Topics: Animals; Bacteriological Techniques; Bacteroidaceae Infections; Cell Culture Techniques; Cell Line; Cell Movement; Chemotaxis, Leukocyte; Concanavalin A; Cytokines; Fimbriae, Bacterial; Hypercholesterolemia; Inflammation Mediators; Interleukin-6; Macrophage Activation; Macrophages; Macrophages, Peritoneal; Male; Mice; Mice, Inbred C57BL; Mice, Inbred Strains; Mitogens; Monocytes; Mutation; Porphyromonas gingivalis; Tumor Necrosis Factor-alpha

Topics: Adult; Apolipoproteins A; Apolipoproteins B; Chromatography, Affinity; Concanavalin A; Fatty Acids; Female; Humans; Hypercholesterolemia; Hyperlipoproteinemias; Hypertriglyceridemia; Lipids; Male; Middle Aged

Mammalian, cardiac endothelium has a surface topography that is characterized by plasmalemmal microappendages, nuclear bulges and ruffled cellular margins. SEM of the endothelial population over the two surfaces of the anterior cusp (leaflet) of the rabbit mitral valve revealed a very pleomorphic topography. The atrial and ventricular surfaces of the cusp displayed differences in microappendage population, cell density, nuclear contour and surface reactivity to Ruthenium Red and Concanavalin A. Comparative studies of similar populations from diet-induced hypercholesterolemic rabbits suggested an enhanced endothelial permeability as observed by an increase in cytoplasmic vesicles containing RR or Con A and by their intercellular passage into the subendothelium. Concomitant with these changes were disproportionate responses in the surface reaction of the carbohydrate cell coat (glycocalyx). The endothelial cells over the ventricular surface of the anterior cusp displayed the most dramatic changes with the appearance of numerous microappendages and intercellular fenestrations, the loss of RR and Con A surface reaction and the engorgement of the adjacent intima with foam-like cells containing the surface markers. Such surface responses appeared to precede or accompany alterations in endothelial integrity which suggests the importance of the blood-endothelial interface in the maintenance of the vascular wall.

Topics: Animals; Cholesterol; Cholesterol, Dietary; Concanavalin A; Coronary Circulation; Dogs; Endothelium; Hypercholesterolemia; Intercellular Junctions; Male; Microscopy, Electron, Scanning; Mitral Valve; Rabbits; Ruthenium Red

Cholesterol-induced density lipoprotein(s), termed HDLc, is one of the abnormal lipoproteins which occur in experimental hypercholesterolemia in several animal species, including rats. Thus far, HDLc has been exclusively isolated by sequential ultracentrifugation followed by Geon-Pevikon block electrophoresis, which is time-consuming and requires some specialized knowledge. In this report, a faster and more convenient alternative method for the isolation of HDLc is described. A combination of a single ultracentrifugation and agarose gel chromatography followed by concanavalin A-Sepharose affinity chromatography was employed. HDLc thus obtained was similar to and probably identical with the HDLc isolated by Geon-Pevikon electrophoresis, with respect to chemical composition, electrophoretic properties in agarose gel, apoprotein patterns in SDS polyacrylamide gel electrophoresis, and electron micrographic appearance.

Topics: Animals; Apoproteins; Cholesterol, Dietary; Chromatography, Affinity; Concanavalin A; Electrophoresis; Hypercholesterolemia; Lipoproteins; Lipoproteins, HDL; Male; Microscopy, Electron; Rats; Rats, Inbred Strains

The sulfated glycosaminoglycan, heparin, was found to release 125I-labeled low density lipoprotein (125I-LDL) from its receptor site on the surface of normal human fibroblasts. Measurement of the amount of 125I-LDL released by heparin permitted the resolution of the total cellular uptake of 125I-LDL at 37 degrees C into two components: first, an initial rapid, high affinity binding of the lipoprotein to the surface receptor, from which the 125I-LDL could be released by heparin, and second, a slower process attributable to an endocytosis of the receptor-bound lipoprotein, which rendered it resistant to heparin release. At 4 degrees C the amount of heparin-releasable 125I-LDL was similar to that at 37 degrees C, but interiorization of the lipoprotein did not occur at the lower temperature. The physiologic importance of the cell surface LDL receptor was emphasized by the finding that mutant fibroblasts from a subject with homozygous Familial Hypercholesterolemia, which lack the ability to take up 125I-LDL at 37 degrees C, did not show cell surface binding of 125I-LDL, as measured by heparin release, at either 4 degrees C or 37 degrees C. Although heparin released 125I-LDL from its binding site, it did not release 3H-concanavalin A from its surface receptor, and conversely, alpha-methyl-D-mannopyranoside, which released 3H-concanavalin A, did not release surface-bound 125I-LDL. When added to the culture medium simultaneously with LDL, heparin prevented the binding of LDL to its receptor and hence prevented the LDL-mediated suppression of 3-hydroxy-3-methylglutaryl coenzyme A reductase activity. The uptake of LDL by fibroblasts is proposed as a model of receptor-mediated adsorptive endocytosis of macromolecules in human cells.

Topics: Cell Membrane; Cells, Cultured; Chondroitin Sulfates; Concanavalin A; Dermatan Sulfate; Endocytosis; Heparin; Hypercholesterolemia; Lipoproteins, LDL; Methylmannosides; Receptors, Drug; Temperature

Long-term established human lymphoid cells were shown to possess high affinity cell surface receptors for low density lipoprotein (LDL), the major cholesterol-carrying protein in human plasma. Binding of LDL to these receptors was followed by internalization of the lipoprotein and hydrolysis of its protein and cholesteryl ester components. Cultured lymphocytes from a patient with the homozygous form of familial hypercholesterolemia lacked cell surface LDL receptors and therefore failed to take up and degrade the lipoprotein with high affinity. Cultured human lymphocytes should prove useful for further studies of: (a) the relation between cholesterol metabolism and cellular function and (b) the mechanism by which LDL binding at the cell surface leads to internalization of the lipoprotein.

Topics: Apoproteins; Binding Sites; Biological Transport; Cell Line; Cholesterol; Concanavalin A; Homozygote; Humans; Hydrolysis; Hypercholesterolemia; Lipoproteins, HDL; Lipoproteins, LDL; Lymphocytes; Receptors, Drug