A Probiotic Mixture Including Galactooligosaccharides Decreases Fecal beta-Glucosidase Activity but Does Not Affect Serum Enterolactone Concentration in Men during a Two-Week Intervention

Peer reviewe

The effect of consumption of milk fermented by Lactobacillus casei strain Shirota on the intestinal microflora and immune parameters in humans.

Objective: To determine the effect of consumption of milk fermented by Lactobacillus casei strain Shirota (L. casei Shirota) on the composition and metabolic activities of the intestinal microflora, and immune parameters in humans. Subjects: Twenty healthy male subjects aged 40-65 years were selected. Design: A placebo-controlled trial was performed in which 10 subjects were randomly assigned to a control and 10 to a treatment group. During the first and last two weeks of the 8-week study the subjects received a strictly controlled diet without fermented products. The same controlled diet was given during the intermediate 4-week test period but then the treatment group received three times daily 100 ml of fermented milk containing 109 CFU L. casei Shirota/ml, whereas the same amount of unfermented milk was given to the subjects in the control group. Results: In comparison to the control group, the consumption of L. casei Shirota-fermented milk resulted in an increase of the Lactobacillus count in the faeces in which the administered L. casei Shirota was predominant at the level of 107 CFU/g wet faeces. This was associated with a significant increase in Bifidobacterium counts (P < 0.05). Some shifts in the other bacterial species were found, such as a decreased number of Clostridium; however the differences were not statistically different between the treatment and the control groups. The β-glucuronidase and β-glucosidase activities per 1010 bacteria decreased significantly (P < 0.05) at the second week of the 4-week test period with the consumption of L. casei Shirota-fermented milk. Furthermore, the consumption of the fermented milk product resulted in a slight but significant increase in the moisture content of the faecal samples (P < 0.05). No treatment effects were observed for any of the immune parameters measured (including natural killer (NK) cell activity, phagocytosis and cytokine production). Conclusions: The results suggest that consumption of L. casei Shirota-fermented milk is able to modulate the composition and metabolic activity of the intestinal flora and indicate that L. casei Shirota-fermented milk does not influence the immune system of healthy immunocompetent males

Oral sensitization to food proteins: A Brown Norway rat model

Background: Although several in vivo antigenicity assays using parenteral immunization are operational, no adequate enteral sensitization models are available to study food allergy and allergenicity of food proteins. Objective: This paper describes the development of an enteral model for food allergy research in the Brown Norway (BN) rat. Methods: The animals were exposed to ovalbumin either ad libitum via the drinking water (0.002 to 20mg/mL) continuously for 6 weeks or by garage (1 mg/mL per rat). Garage dosing was performed either daily, twice a week, once a week or once every 2 weeks during a period of 6 weeks. No adjuvants were used during the sensitization studies. Results: After intra-gastric administration of ovalbumin once or twice a week or once every two weeks, no or only a very low frequency of ovalbumin-specific antibody responses were detected. Daily intra-gastric dosing with ovalbumin resulted in antigen-specific IgG as well as IgE responses in almost all animals tested. Upon ad libitum exposure, ovalbumin-specific IgG but no ovalbumin-specific IgE was detected. The cellular response was examined by determination of delayed-type hypersensitivity (DTH) reactions in the animals dosed by daily garage and in the ad libitum exposed rats. Both sensitization protocols sensitized for DTH The response was most pronounced in ad libitum exposed rats at day 28 of exposure. Conclusions: These studies show that the BN rat may provide a suitable animal model for inducing specific IgG and IgE responses as well as specific T-cell mediated hypersensitivity (DTH) to ovalbumin upon exposure via the enteral route without the use of adjuvants

The evaluation of the immunomodulating properties of ERA-63 a pharmaceutical with estrogenic activity

This paper describes studies performed with ERA-63 a low molecular weight pharmaceutical with intended immunomodulatory effects. Since this compound was also known to have estrogenic activity a non-conventional approach was taken in order to differentiate between estrogenic and non-estrogenic-induced immunomodulatory effects. EE was included not only for qualitative comparison (hazard identification) between immunomodulatory effects but also, in case of similar effects, to facilitate the extrapolation of the findings in the rat to anticipated effects in humans. After 28 days of treatment with dosages ranging from pharmacological up to clearly toxic levels for both compounds the immunotoxic potential was assessed by performing a T cell-dependent antibody response and a host resistance assay in rats. Selected ERA-63 dose levels (0.167-0.2, 1.67-2 and 16.7-20 mg/kg) were expected to have comparable estrogenic activity to respective EE dose levels (0.05, 0.5 and 5 mg/kg). General toxicity parameters reflecting estrogenic activity (i.e. decreased body- and organ weights of thymus and testis, and increased bilirubin and GGT levels) confirmed the comparable estrogenic activity for both compounds at the dose levels tested. Together with the comparable estrogen-related immune suppression (i.e. decreases in specific antibody responses and an increased susceptibility for Listeria monocytogenes infects) for both compounds, this indicates that available clinical data for EE facilitates the human risk assessment of ERA-63. © 2008 Elsevier Ireland Ltd. All rights reserved