DNA from inactivated "probiotic" bacteria triggers a specific anti-inflammation immune response in mice with experimental colitis, researchers supported by the NIH's National Institute of Allergy and Infectious Diseases (NIAID) have discovered. Led by Eyal Raz, M.D., of the University of California, San Diego (UCSD), the investigators provide a possible explanation for the observed benefits of consuming probiotics, supplements from bacteria and other microbes, regarded by some as helpful in maintaining or restoring intestinal health. Knowing how probiotics work could give scientists a way to identify and select which probiotic bacteria might be effective against such human ailments as inflammatory bowel disease (IBD).
Probiotics have shown promise for treating such IBDs as Crohn's disease and ulcerative colitis, both of which cause periodic intestinal inflammation. But scientists have had many theories of how these mixtures of "good" bacteria work, notes Marshall Plaut, M.D., of NIAID's Division of Allergy, Immunology and Transplantation. Plausible theories suggested that proliferation of the living bacteria either generated helpful metabolic products or crowded out "bad" intestinal bugs. Prior to this study, the general thinking about probiotics, which include bacteria like those found in yogurt, has been that they mediate their effects through some kind of non-specific action, adds Dr. Plaut.
Dr. Raz and his colleagues, whose work is published in the February 2004 issue of the journal Gastroenterology, irradiated a commercially available probiotic preparation, halting bacterial proliferation, but preserving its DNA. When given to mice, the irradiated probiotics performed as well as live bacteria in reducing inflammation. They also found that purified probiotic bacterial DNA alone similarly reduces inflammation in mice with experimentally induced colitis.
The researchers also showed that probiotic DNA acts in a specific way by activating Page: 1 2 Related medicine news :1
Contact: Anne A. Oplinger
NIH/National Institute of Allergy and Infectious Diseases
. Bacterial infection may cause or worsen asthma attacks in children2
. Bacterial protein kills tumors3
. Bacterial vaginosis seems to affect miscarriage in early pregnancy4
. Geodon effective in psychiatric emergencies; Sharply reduces time in restraints5
. Targeting mutant B-Raf protein reduces melanoma development6
. Rasagiline reduces disability for patients with advanced Parkinsons disease7
. Breast cancer treatment reduces risk of heart disease8
. Carrot component reduces cancer risk9
. Sex hormone metabolite reduces stress, anxiety in female rats10
. Sunlight reduces risk of lymph gland cancer11
. Male circumcision reduces risk of HIV transmission from women to men