Effects of a phytopreparation from Helleborus niger on immunocompetent cells in vitro.

Extracts of Helleborus species are used as phytopreparations with immunostimulatory properties in Romanian traditional medicine. In Germany, Helleborus niger is used in homeopathy and as an adjuvant therapy in the treatment of tumor patients in anthroposophical medicine. In vitro application of an aqueous extract from Helleborus niger resulted in a slight induction of sister chromatid exchanges (SCE) in cultured peripheral blood mononuclear cells (PBMC) from healthy individuals, an effect associated with a slight increase of the [3H]thymidine uptake in the DNA of isolated lymphocytes. Since the cytokines interleukin (IL)-2 and tumor necrosis factor (TNF)-alpha were reported to increase the number of SCE, we measured the concentrations of these cytokines in the supernatants of cultured PBMC treated with the plant extract. Here, no significant changes were observed as compared with the controls, but a trend to higher supernatant concentrations of TNF-alpha in six out of ten individuals was noted. Compared with lymphocytes treated with the alkylating substance, cyclophosphamide, the increase of the SCE levels induced by the plant extract is weak. The relevance of this DNA destabilizing property remains to be clarified.

Differences in the apoptosis-inducing properties of Viscum album L. extracts.

Viscum album L. (mistletoe) extracts are widely used in adjuvant cancer therapy. In contrast to purified components, such as mistletoe lectins and viscotoxins, whole plant extracts of mistletoe resulted in DNA stabilizations in cyclophosphamide-treated lymphocytes but also provided cytotoxicity in tumour cells and lymphocytes. The killing capacities of mistletoe extracts were host tree-specific and not correlated with mistletoe lectin or viscotoxin content. In human lymphocytes, only mistletoe lectins induced a pathway of apoptotic killing. Within 72 h, the lectin B chains also increased the number of lymphocytes undergoing apoptosis. This finding suggests that inhibition of protein synthesis by the A chain of the hololectin may accelerate a receptor-mediated killing pathway induced by the B chains. An unexpected finding was related to the mistletoe-mediated killing, which was more effective against CD8+T cells with an activated phenotype than CD19+ B cells and CD4+ T cells. In vitro treatment of human neutrophils with mistletoe resulted in a slight decrease of phagocytosis and burst activity. The observed dose-dependent occurrence of two neutrophil subsets with different burst activities indicates differences in their susceptibility to mistletoe and suggests the implication of an induction of the apoptotic killing pathway.

Induction of apoptosis in human lymphocytes treated with Viscum album L. is mediated by the mistletoe lectins.

Viscum album L. (VAL) is a phytopreparation used in adjuvant cancer therapy with both immunostimulatory and DNA stabilizing properties at low drug concentrations and cytostatic/cytotoxic properties at higher concentrations. The present work examines the cytotoxic effects of VAL extracts produced from mistletoes grown on different host trees and of purified toxic proteins from VAL, such as the D-galactose-specific lectin I (ML I), the N-acetyl-D-galactosamine-specific ML II and ML III, and crude viscotoxins towards cultured human lymphocytes. The decrease in the number of cultured lymphocytes and blast cells treated with whole plant extracts from VAL was host tree-specific. Nevertheless, there was no close correlation to the content of MLs or viscotoxins. Using the purified proteins, it became obvious that the cell killing was mediated by the induction of apoptosis, as measured by the appearance of a hypodiploid DNA peak using flow cytometry. ML III was the most effective to induce apoptosis, followed by ML II and ML I, while the viscotoxins and oligosaccharides from VAL did not. By measuring the surface expression of IL-2R alpha chains, transferrin receptors and APO-1/Fas molecules on non-apoptotic T cells, no significant changes were observed at low ML concentrations (1 ng/ml), but their decrease at higher ones. Our findings suggest that there might be at least two different ways of cell killing operative in VAL-mediated cytotoxicity: (a) the typical apoptotic cell death with the appearance of hypo-diploid nuclei, and (b) a direct or indirect killing by damaging the cell membrane with subsequent influx of Ca2+ and of the DNA intercalating dye propidium iodide and cell shrinkage. These effects might not be exclusive, as they probably occur simultaneously.

Effects of Viscum album L. on cyclophosphamide-treated peripheral blood mononuclear cells in vitro: sister chromatid exchanges and activation/proliferation marker expression.

Based on recently published data, Viscum album L. (VAL) extracts have been shown to provide a DNA stabilizing effect which seems to be restricted to the peripheral blood mononuclear cells (PBMC). We have now investigated whether VAL exerts effects of cellular protection for phytohemagglutinin-activated PBMC treated with cyclophosphamdie (CP) in vitro. The addition of VAL resulted in a slight reduction of CP-induced sister chromatid exchanges of cultured PBMC from healthy individuals. The incubation with CP significantly reduced the expression of the low affinity interleukin-2 receptor (IL-2R alpha chain) and of transferrin receptor (TfR) on PHA-stimulated T lymphocytes. The addition of 10 micrograms/ml VAL was protective against the CP-induced depression of IL-2R alpha chain and TfR expression on these cells. The simultaneous addition of CP and purified VAL components, such as ML I, ML II/III, and viscotoxins did not significantly change expression of IL-2R alpha chain and TfR on T cells. Thus, so far undefined VAL components might be responsible for the observed protection effects of the whole plant extract. The results presented here should encourage investigation of this drug, which might become an interesting adjuvant in cancer therapy.

Effect of Viscum album L. on rapidly proliferating amniotic fluid cells. Sister chromatid exchange frequency and proliferation index.

Amniotic fluid cells (AFC) from 10 women undergoing amniocentesis were investigated. The 5-bromo-2'-deoxyuridine-induced sister chromatid exchange (SCE) frequency of AFC remained stable after the addition of a therapeutical concentration of Viscum album L. preparation Iscador P but decreased significantly after administration of high drug doses. As the proliferation index remained stable, even at extremely high drug concentrations, this effect could not be ascribed to a reduction of proliferation. No indications of cytogenetic damage or effects of mutagenicity were seen after the addition of Viscum album L. preparation P.

Viscum album L. extracts reduce sister chromatid exchanges in cultured peripheral blood mononuclear cells.

Increasing concentrations of Viscum album L. extracts were shown to significantly reduce sister chromatid exchange (SCE) frequency of phytohaemagglutinin (PHA)-stimulated peripheral blood mononuclear cells (PBMC) of healthy individuals. This decrease of SCE could not be explained either by changes in lymphocyte subpopulations, by cytostatic effects of the drug or by accelerated proliferation of PHA-stimulated PBMC. Currently, no other cells tested have shown this effect. One therapeutic effect of these anti-mutagenic drugs could be a stabilisation of mononuclear blood cell DNA.

Traditional medicine: institutional perceptions and cultural realities.

Strong interest has developed in the integration of traditional health practices with modern or Western health services, i.e. a fusion of "traditional medicine" and "modern medicine". Pervasive complications, both structural and functional, appear inherent yet not irresolvable in such a fusion. These difficulties are assessed, using examples from the Papua New Guinean situation, and some suggestions are made towards achieving integration of the two modes, with attention also to primary-level health care programmes.