- 1 Probiotics
- 2 Probiotics: Why we care
- 3 Probiotics in Healthcare: Current and Future Approaches
- 4 Oversight of Probiotics
- 5 iGEM 2009: Stanford's Approach to Probiotics
- 6 Probiotics and the Media links
- 7 References
A probiotic (from the Latin, pro-, "in favor, for" and the Greek , biōtikós, "pertaining to life")refers to live microorganism that provides a benefit to the host, either directly or indirectly, by via interactions with the hosts cells or the host's microbiota. Such microorganism will interact by producing bioactives, biological compounds and macromolecules, that will produce such benefit.Although the concept of a probiotic has evolved since the the last century and the the first years of the current century that it acquired the current definition and we can see the health benefits humans can gain from he understanding of such interactions. Some research currently ongoing include the Human Microbiome Project, and the use on single organisms to prevent disease. For example, the use of fecal transplantation for antibiotic-associated diarrea.
Probiotics: Why we care
Probiotics in Healthcare: Current and Future Approaches
Oversight of Probiotics
United States Regulation of Probiotics
Probiotics are currently regulated by the Food and Drug Administration (FDA)in one of the following ways; As a dietary supplement, in which case only a premarket notice to the FDA is necessary or as a drug in which case a premarketing safety, efficacy and approval by the FDA are required. Currently, most of the probiotics on the market fall under the umbrella of a dietary supplement, but situations where the number of infections and the severity of such cases are causing clinicians to evaluate their use as drug, as it's happening for Clostridium difficile infections. In such cases, Florastor (Saccharomyces boulardii) a probiotic currently marketed as a drug is beneficial as it demonstrated its efficacy in reducing the recurrence of C. difficile when used in combination with standard treatment methods. Although cases in which Florastor has lead to fungemia,yeast present in the blood, have been reported, mostly in patients that were not receiving the treatment via introduction of live yeast from contaminated hands of a technician to a catheter site.
Global Standardization of Guidelines of Probiotics
The first effort to establish global guidelines were made in 2001 when a Joint Food and Agriculture Organization of the United Nation and the World Health Organization meeting was organized. The following guidelines were proposed:
- Testing and Clinical Guidilines
- Identify the genus and species of the probiotic strain, phenotipically and genotipically.
- Perform in vitro testing of the probiotic mechanism of action.
- Do clinical trials pre- and postmarketing to provide substantiation to the claim it makes.
- Safety Assesment Guidilines
- Identify the patterns of antimicrobial resistance of the probiotic.
- Characterize its metabolism.
- Identify possible side effects in humans which could include:
- Production of a toxin that causes adverse health effects
- Test its hemolytic potential
- Test for lack of infectivity.
iGEM 2009: Stanford's Approach to Probiotics
The 2009 Stanford iGEM Team project centered on probiotics and Inflammatory Bowel Disease (IBD). IBD, as explained, is caused by an imbalance of two types of T-cells, Treg cells that immunosuppres the Th17 cells that cause the inflammation seen in patients. They suggest that an novel theraputic mechanism can be achieved by in vivo regulation of these cells. Their approach focuses in constructing two different Escherichia coli(E.coli) strains, each that would contain a distinct input/output cassette , each that is referred as a device. The first device would detect as input Nitric Oxide(NO), a byproduct of inflammation and Th17 proliferation, produces retinoic acid, that blocks further CD4+ T-cells differentiation into Th17 cells. The second device detects 5-Methyl tryptophan (5MT) as an input and produces Interleukin-6 to regulate Treg proliferation to regulate their immunosuppression response. Ideally depending on the balance between these two markers, if too much NO is sensed by Device 1 it would prevent inflammation. The opposite would also be true if the second device sences to much 5MT that would immunosuppress Th17 cell by blocking their differentiation.
The Media perspective on Probiotics
- Romero PA and Arnold FH. Exploring protein fitness landscapes by directed evolution. Nat Rev Mol Cell Bio, 2009.
- Crameri A, Whitehorn EA, Tate E, Stemmer WP. Improved green fluorescent protein by molecular evolution using DNA shuffling. Nat Biotechnol, 1996.
- Giver L, Gershenson A, Freskgard PO, Arnold FH. Directed evolution of a thermostable esterase. Proc Natl Acad Sci USA, 1998.
- Cadwell RC and Joyce GF. Randomization of genes by PCR mutagenesis. Genome Res, 1992.
- Abou-Nader M and Benedik MJ. Rapid generation of random mutant libraries. Bioeng Bugs, 2010.
- Stemmer WP. Rapid evolution of a protein by in vitro DNA shuffling. Nature, 1994.
- Lin H and Cornish VW. Screening and selection methods for large-scale analysis of protein function.
- Leemhuis H, Kelly RM, Dijkhuizen L. Directed evolution of enzymes: library screening strategies. IUBMB Life, 2009.