Bioavailability and pharmacokinetics of Echinacea purpurea preparations and their interaction with the immune system

Echinacea is a widely used herbal remedy for the prevention and treatment of the common cold. Recently, many new insights concerning the molecular mode of action of the main lipophilic constituents, the alkamides, have renewed interest in this plant. In order to compare the bioavailability of alkamides from liquid and tablet preparations of E. purpurea (Echinaforce) in humans and to study the effects on ex vivo stimulated blood cells, a randomized, single-dose, crossover study with 10 (8 test, 2 placebo) volunteers has been performed. They received either 4 ml of the standardized E. purpurea (Echinaforce) tincture or 12 E. purpurea (Echinaforce) tablets or placebo. Both doses contained the same amount (0.07 mg) of the major alkamides, dodeca-2E,4E,8Z, 10E/Z-tetraenoic acid isobutylamides. Liquid chromatography electrospray ionization ion-trap mass spectrometry was used to determine the content of alkamides in serum. It was found that the arithmetic mean C(max) of dodeca-2E,4E, 8Z,10E/Z-tetraenoic acid isobutylamides absorbed after oral application of the Echinaforce tincture appeared after 30 min (0.40 ng/ml serum). In comparison, the t(max) of tablets was 45 min with a C(max) of 0.12 ng/ml. An ex vivo stimulation of blood by LPS was carried out to measure the influence of E. purpurea on the innate and adaptive immune system. Both E. purpurea preparations led to the same effects on the immune system according to the concentration of pro-inflammatory cytokines TNF-alpha and IL-8. 23 hours after oral application a significant down-regulation of TNF-alpha and IL-8 in LPS pre-stimulated whole blood was found. However, no significant changes in the concentration of IL-6 were observed. Although a quarter of the dodeca-2E,4E,8Z, 10E/Z-tetraenoic acid isobutylamides was absorbed from the tablets, the study shows that the formulations trigger the same effects on the measured immune parameters.

The effect of heavy metals on the immune system at low concentrations

The present study describes the effect of cadmium on lymphokines that cannot be directly traced to an allergen, or antigen in order to be able to explain various immunological processes. Exposure to various environmental pollutants is known to induce epithelial and inflammatory changes, characterized by a release of cytokines and other soluble mediators. Heavy metals like CdCl2 can induce, or inhibit the synthesis and expression of the inflammatory cytokines IL-1beta, IL-4, IL-6, TNF-alpha, IFN-gamma and ICAM-1. Normal human peripherial blood mononuclear cells (PBMCs) were exposed for different periods of times (1 to 96 h) to 0, 5, 25 and 50 micromoles CdCl2, and mRNA for the above cytokines was quantified by RT-PCR. Highly purified blood B cells and PBMCs from healthy donors were stimulated with IL-4 and aCD40 mAb and incubated with non-toxic concentrations of cadmium chloride (0,1-10 micromol). Levels of IgG and IgE were measured in the supernatants. Proliferation and expression of surface markers were determined by measuring [3H]-thymidine incorporation and by flow cytometry. The study showed that the in vitro synthesis of IgE by purified B cells or PBMCs stimulated with IL-4/aCD40 is inhibited by Cd at doses as low as 0,1 microM. Cd was found to inhibit IL-4/aCD40 induced proliferation of purified B cells and PBMCs in a dose dependent fashion. Most strikingly, only IgE but not IgG synthesis of purified B cells was inhibited by Cd. These data suggest that inhibition of IgE synthesis in human B lymphocytes by Cd seems to be a selective effect on immunoglobulin synthesis.

Albumin is a necessary stabilizer of TBE-vaccine to avoid fever in children after vaccination

A thiomersal-free and also an albumin-free tick-borne encephalitis-vaccine (TBE-vaccine) was developed. This vaccine was approved by the Austrian health authorities in the year 2000. Contrary to previous experience, 779 cases of fever attacks occurred following the first vaccination of children under 15 years of age. The induction of the immune system by different TBE virus (TBEV) vaccines (FSME-Immun [1999], Ticovac [2000] and FSME-Immun [2001] all from Baxter Hyland Immuno, Vienna) was compared in an in vitro immune stimulation test in order to find an explanation for the unexpected fever attacks. It was shown that only Ticovac, which contains no albumin as a stabilizer, can induce relative high amounts of TNF-alpha (P < or = 0.0001) and lower amounts of IL-1 beta (P < or = 0.05). Increase of both cytokines is first observed following an incubation of 4 h. The maximum is reached after 15 h. After 26 h, it has reverted to the original value. The course of concentration of both cytokines corresponds to the time of observed febrile phases. Albumin or immunoglobulin prevents a rise of cytokines so that it is recommended to add the albumin again to the vaccine.

In vitro cytokine mRNA expression in normal human peripheral blood mononuclear cells

OBJECTIVE AND DESIGN

Normal human peripheral blood mononuclear cells (PBMC) were analyzed for basic profiles of mRNA expression of distinct genes during incubation in a standard cell culture system.

MATERIAL

Human PBMC from healthy adult blood donors.

METHODS

Steady-state mRNA expression was measured using a semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) assay.

RESULTS

Shortly after isolation and cell seeding, mRNA levels of monocyte-derived cytokines (IL-1alpha, IL-6, and TNF-alpha) were significantly increased, whereas lymphocyte-derived cytokines (IL-4, IFN-gamma) were not affected. Expression levels of monokines returned to basal within 24 h. At later stages of culture, the mRNA levels of all genes studied gradually increased and were significantly elevated after 96 h of incubation.

CONCLUSIONS

Monokine and lymphokine mRNAs respond differently to cell culture even under control conditions. With regard to the enhanced mRNA expression of distinct cytokines in the early stages of culture, human PBMC should not be used for gene expression studies in vitro within 24 h of isolation.

Analysis of hsp70 mRNA levels in HepG2 cells exposed to various metals differing in toxicity

Human hepatoma cells (HepG2) were exposed to several heavy metal salts and the induction of heat shock protein 70 (hsp70) mRNA was analysed by the reverse transcriptase-polymerase chain reaction (RT-PCR). Metals were added to the cell medium at concentrations ranging from 0.1 to 100 microM and incubation was continued for 4 h. In addition we analysed the time dependence of hsp70 induction by adding each metal at a certain concentration followed by an incubation for 0.5 to 24 h. CdCl2, NaAsO2, AgNO3 could be classified as very strong inducers (20-, 13- and 10-fold above control level) and they reached their maximum level of induction at 1-10 microM after 2 h. CuCl2, MnCl2, Pb(NO3)2, TlNO3, CoCl2 and NiCl2 were also strong inducing agents, giving a 4-6 fold induction at 10-100 microM after 4-8 h. ZnSO4, Hg(NO3)2 and AlCl3 were only weak inducers (1.5-2 fold at 50-100 microM after 4-8 h) of hsp70 mRNA. Cytotoxic effects (measured by release of lactate dehydrogenase) could only be detected for 100 microM Hg2+ after 4 h and when the cells were incubated with 5 microM Cd2+ for more than 8 h. We also tested a few combinations of these heavy metal salts for their hsp70-inducing ability. Zn2+ and Mn2+ were able to diminish Cd2+ induced hsp70 mRNA levels by 65%. Ag+ mediated induction was reduced by 40% when combined with Cu2+, whereas Hg2+ increased induction by Ag+ about 3-fold and led to a dramatic decrease in cell viability. In our study we were able to demonstrate that the analysis of hsp70 mRNA levels in chemically stressed HepG2 cells by RT-PCR can be a valuable tool for studying mechanisms of toxicity associated with elevated expression of hsp70.

Total serum IgE concentration of children from air-polluted regions

Distributions of IgE levels were determined from 312 children (divided into three age groups), living in small Austrian towns with different levels of air pollution. The spread of IgE concentration was extremely wide; the mean value was 124 kU/I with a standard deviation of 240. An increase of concentration was found in the group aged 6 to 11 years. No significant difference was found according to sex and the higher rates of IgE. The reference rates were then used to compare children living in an industrial region with heavy metal production. A significant difference was found in the lower IgE concentrations (25th and 50th percentiles).

Rapid detection of Legionella species in bronchoalveolar lavage fluids with the EnviroAmp Legionella PCR amplification and detection kit

A molecular assay based on a rapid DNA extraction protocol and the EnviroAmp Legionella Kits was used to detect Legionella species in bronchoalveolar fluid specimens. All Legionella strains isolated from tap water in hospitals could be detected distinctly. Both sensitivity and specificity were tested. In a prospective study, bronchoalveolar lavage fluids obtained from patients with atypical pneumonia were investigated. Three positive samples were detected with the molecular techniques and were subsequently confirmed by culture. Application of the system described may lead to safe and early diagnosis of Legionnaires' disease in patients with atypical pneumonia.