Alzheimer’s disease and the microbiome

Excerpt of conclusions in the article cited in the link below regarding the use of probiotics to treat neurological disorders. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3775450/

Hence, for well over 100 years, host-beneficial GI tract bacteria, collectively known as probiotics, have been proposed to be useful to human health, and more recently have been added to various foods and diets because of their positive health-promoting effects (Singh et al., 2013).

The beneficial actions of bacterial-based probiotics are highly inter-related, and are thought to function, in part: (i) to aid in complex carbohydrate fermentation and absorption; (ii) to provide a significant source of a range of essential vitamins, particularly those of the vitamin B and K group; (iii) to compete with pathogenic microorganisms in the GI tract; (iv) to antagonize and neutralize enteric pathogens; (v) to metabolize and neutralize dietary carcinogens; and (vi) to favorably modulate the host’s immune response to resist infection and disease.

Besides the potential application of probiotics in the prevention and treatment of various health conditions and diseases such as allergies, GI and urogenital tract infections, inflammatory disease, cystic-fibrosis and certain cancers there is increasing interest of positive microbiome effects toward the CNS via neural, neuroendocrine, neuroimmune and humoral links (Duncan and Flint, 2013; He and Balling, 2013; Saulnier et al., 2013).

For example, there is preliminary research on the influence of probiotics and nutritional factors on the prognosis of multiple sclerosis (von Geldern and Mowry, 2012), cognition (Camfield et al.,2011), neurogastroenterology in general (Saulnier et al., 2013), and stress-related psychiatric conditions including anxiety, autism, depression and schizophrenia (Bravo et al., 2012; Prasad et al., 2012; Douglas-Escobar et al., 2013). Advances in probiotic technologies in CNS disease research are already raising a number of ethical, legal, and socioeconomic concerns (Slashinski et al., 2012).

Lastly, the US NIH “Roadmap” program has recently initiated the HM project, using recently discovered genomic technologies with the specific aims (i) to characterize the microbial communities at several different sites on the human body, including nasal, oral and otic cavities, the skin, GI and urogenital tracts; (ii) to analyze the role of these microbes in homeostatic human physiology; (iii) to catalog specific microbiome speciation, composition and correlation with disease; and (iv) to generate resources enabling comprehensive characterization of the HM by multiple independent research groups.

These investigations present a highly significant and exciting avenue for future study, and suggest new and perhaps unconventional directions for AD research in 2013 and beyond. Future AD therapies may well, in part, involve probiotic approaches, especially as a prophylactic tactic before mild-cognitive impairment (MCI) or AD is first diagnosed. The implications of altered host-HM interactions in neurological disease would be far-reaching indeed, and these may engender novel microbiome manipulative strategies, tailored to the host, for the more effective therapeutic management of AD and related neuropsychiatric disorders.

Front Cell Neurosci. 2013; 7: 153. Published online 2013 Sep 17. doi:  10.3389/fncel.2013.00153