Chronic kidney disease alters intestinal microbial flora

The population of microbes (microbiome) in the intestine is a symbiotic ecosystem conferring trophic and protective functions. Since the biochemical environment shapes the structure and function of the microbiome, authors of this research work have tested whether uremia and/or dietary and pharmacologic interventions in chronic kidney disease alters the microbiome.

High throughput DNA sequencing to detect differences in the subgingival plaque microbiome in elderly subjects with and without dementia

To investigate the potential association between oral health and cognitive function, a pilot study was conducted to evaluate high throughput DNA sequencing of the V3 region of the 16S ribosomal RNA gene for determining the relative abundance of bacterial taxa in subgingival plaque from older adults with or without dementia.


Subgingival plaque samples were obtained from ten individuals at least 70 years old who participated in a study to assess oral health and cognitive function. DNA was isolated from the samples and a gene segment from the V3 portion of the 16S bacterial ribosomal RNA gene was amplified and sequenced using an Illumina HiSeq1000 DNA sequencer. Bacterial populations found in the subgingival plaque were identified and assessed with respect to the cognitive status and oral health of the participants who provided the samples.
More than two million high quality DNA sequences were obtained from each sample. Individuals differed greatly in the mix of phylotypes, but different sites from different subgingival depths in the same subject were usually similar. No consistent differences were observed in this small sample between subjects separated by levels of oral health, sex, or age; however a consistently higher level of Fusobacteriaceae and a generally lower level of Prevotellaceae was seen in subjects without dementia, although the difference did not reach statistical significance, possibly because of the small sample size.

The results from this pilot study provide suggestive evidence that alterations in the subgingival microbiome are associated with changes in cognitive function, and provide support for an expanded analysis of the role of the oral microbiome in dementia.

Original Source:

Insight into the bacterial gut microbiome of the North American moose (Alces alces)

The work presented here provides the first intensive insight into the bacterial populations in the digestive tract of the North American moose (Alces alces). Eight free-range moose on natural pasture were sampled, producing eight rumen samples and six colon samples. Second generation (G2) PhyloChips were used to determine the presence of hundreds of operational taxonomic units (OTUs), representing multiple closely related species/strains (>97% identity), found in the rumen and colon of the moose.

The intestinal environment in health and disease - recent insights onthe potential of intestinal bacteria to influence human health

The human intestine is colonized by a complex microbial ecosystem, which could be considered as a separate organ within the human host, having a coding capacity which exceeds the liver by a factor 100. On the one hand, this extensive microbiome is closely involved in the first-pass metabolism and bioavailability of food and drug compounds. Understanding to which extent each individual's gut microbiota affects the bioavailability and response to orally administered drugs is therefore a first important challenge towards novel drug development strategies. On the other hand, as our microbiota is directly or indirectly involved in the onset of a number of disease states, a new generation of therapeutics may be developed that affect the structure and functioning of the intestinal microbiota and interfere with their specific cross-talk with the human host. Ultimately, the intestinal microbiota may even be used as a biomarker for impending diseases inside or outside the gastrointestinal tract and for the evaluation of responses to specific therapeutic interventions. This review will therefore highlight the importance of the indigenous microbial community and its enormous metabolic potential, microbe-microbe interactions, mechanisms of host-bacterium cross-talk and will discuss the onset of obesity, a specific disease state in which the role of intestinal bacteria becomes more and more apparent. Understanding the importance of the intestinal ecosystem in these phenomena may open the door for new strategies which target the management of the intestinal microbiome into the desired direction and therefore to a completely new type of nutrition research and pharmaceutical design.

The normal intestinal microbiota

PURPOSE OF REVIEW: Long neglected and considered a difficult ecosystem to study, several developments have recently converged to renew interest in studying the normal gut microbiota. These include molecular methods of studying the microbiota, improved understanding of host-microbe interactions in health and disease, and the potential for therapeutic manipulation of the microbiota. This review focuses on the most recent work in these areas.

RECENT FINDINGS: Host-microbe signaling in the gut is critical for normal development and homeostasis of the gastrointestinal mucosa. The molecular basis of these interactions promises new therapeutic strategies for various disorders. Particularly noteworthy has been the emergence of evidence for the role of enteric bacterial metabolism in the pathogenesis of disorders ranging from functional and inflammatory bowel diseases to human obesity. Metagenomic and metabolomic profiling of the microbiota, although at an early stage, has demonstrated the range and complexity of the gut ecosystem and cast insights into several diseases. The molecular basis of host-microbe dialogue and the mechanisms by which the host contains enteric bacteria within the lumen has immediate relevance to infectious and chronic inflammatory bowel disease.

SUMMARY: Improved understanding of the normal gut microbiota has made the therapeutic manipulation of the gut ecosystem a valid and realistic future prospect.

Original Source:
http://www.ncbi.nlm.nih.gov/pubmed/17762785

The intestinal microbiome: a separate organ inside the body with themetabolic potential to influence the bioactivity of botanicals

For many years, it was believed that the main function of the large intestine was the resorption of water and salt and the facilitated disposal of waste materials. However, this task definition was far from complete, as it did not consider the activity of the microbial content of the large intestine. Nowadays it is clear that the complex microbial ecosystem in our intestines should be considered as a separate organ within the body, with a metabolic capacity which exceeds the liver with a factor 100. The intestinal microbiome is therefore closely involved in the first-pass metabolism of dietary compounds. This is especially true for botanical supplements, which are now marketed for various health applications. Being of natural origin, their structural building blocks, such as polyphenols, are often highly recognized by the human and especially the intestinal microbial metabolism machinery. Intensive metabolism results in often low circulating levels of the original products, with the consequence that final health effects of botanicals are often related to specific active metabolites which are produced in the body rather than being related to the product's original composition. Understanding how such metabolic processes contribute to the in situ exposure is therefore crucial for the proper interpretation of biological responses. A multidisciplinary approach, characterizing the food and phytochemical intake as well as the metabolic potency of the gut microbiota, while measuring biomarkers of both exposure and response in target tissues, is therefore of critical importance. With polyphenol metabolism as example, this review describes how the incorporation of microbial metabolism as an important variable in the evaluation of the final bioactivity of botanicals strongly increases the relevance and predictive value of the outcome. Moreover, knowledge about intestinal processes may offer innovative strategies for targeted product development.

Original Source:
http://www.ncbi.nlm.nih.gov/pubmed/20655994

Targeting the human microbiome with antibiotics, probiotics, and prebiotics: gastroenterology enters the metagenomics era

Studies of metagenomics and the human microbiome will tremendously expand our knowledge of the composition of microbial communities in the human body. As our understanding of microbial variation and corresponding genetic parameters is refined, this information can be applied to rational remodeling or "tailoring" of human-associated microbial communities and their associated functions.

Gut microbiota: a potential new territory for drug targeting

The significant involvement of the gut microbiota in human health and disease suggests that manipulation of commensal microbial composition through combinations of antibiotics, probiotics and prebiotics could be a novel therapeutic approach.

Data mining the human gut microbiota for therapeutic targets

It is well known that microbes have an intricate role in human health and disease. However, targeted strategies for modulating human health through the modification of either human-associated microbial communities or associated human-host targets have yet to be realized. New knowledge about the role of microbial communities in the microbiota of the gastrointestinal tract (GIT) and their collective genomes, the GIT microbiome, in chronic diseases opens new opportunities for therapeutic interventions.