Suppression of interleukin 2 activity by natural products: effects of serum lipoproteins

Immunosuppressive effect of cyclosporine in the hyperlipidemic rat model

The immunosuppressive effects of 2.5 (n = 6) and 5 mg kg-1 day-1 (n = 7) of cyclosporine (CSA) given intravenously for 9 days to the immunized, hyperlipidemic Zucker rat model were compared with drug-free animals (n = 6) and lean litter-mates given 0 (n = 6), 5 (n = 6), and 10 mg kg-1 day-1 (n = 8) of CSA. Thus, based on body weights, both obese rats and lean litter-mates received total doses of 0, 1, and 2 mg of CSA. No significant differences in percent change in baseline body weight were found; in contrast, spleen weights were markedly greater in treated animals compared with controls. Serum cholesterol, triglycerides, and lipoprotein levels of obese rats were significantly greater than values found in lean litter-mates. CSA concentrations in whole blood, serum, and the lipoprotein fractions obtained 4 h after the final dose were greater in obese rats compared with lean litter-mates. Immunosuppressive activity, as assessed by ex vivo T-lymphocyte proliferation assay, was equivocal between all rats given CSA, independent of dose and obesity, and significantly greater than control animals. Whereas serum CSA levels were correlated to cholesterol levels (r = 0.95, p < 0.0001), there were no significant correlations with immunosuppressive activity. The present data suggest that increased binding of CSA to lipoproteins in the vascular compartment does not significantly impact on its immunosuppressive activity.

Muramyl dipeptide-induced changes in murine splenocyte responses to concanavalin A

The effect of muramyl dipeptide (MDP) on Con A-stimulated activation of murine spleen cells was studied. MDP was found to enhance or suppress the proliferative response of splenocytes when different concentrations of Con A were used. MDP was shown to change the IL-2 content in culture supernatants of stimulated cells and to influence IL-2-dependent proliferation of Con A-blasts. A high degree of correlation was found between the proliferation of Con A-blasts and the expression of IL-2 receptors on Con A-blasts. This correlation, however, disappeared in the presence of MDP. The effects of MDP were shown to depend on the level of initial cell activity or rather on conditions leading to a given initial activity of cells.

Angiogenesis in arteries: review

The inner parts of the walls of large blood vessels do not normally contain intrinsic vasculature. In pathologic conditions such as arteriosclerosis or thrombosis, angiogenesis occurs, and may have significant clinical consequences. This review attempts to relate the little that is known about the factors specific to vascular walls which regulate angiogenesis to more general knowledge of the phenomenon.