THE TRANSPLANT OF INTESTINAL FLORA OFFERS NEW POSSIBILITIES FOR THE TREATMENT OF METABOLIC DISEASES AND DIGESTIVE DISORDERS
Investigators from the Vall d’Hebron Research Institute (VHIR), together with Roderic Guigó from the Centre for Genomic Regulation (CRG), have presented unprecedented research demonstrating that it is possible to modify the floral composition of the intestine through transplantation and that the changes generated are, unexpectedly, retained for up to three months after the transplant.
The study, published on the 24th August in the journal Genome Research, establishes that it is possible to introduce new species to the normal intestinal flora simply by ingesting them and postulates that it is not necessary to use antibiotics to first eliminate part of the existing flora, as was previously thought.
The investigation, carried out on mice, has many important implications for human health. The functionality of the genes of the bacteria found in our intestine is key to specific diseases in which bacteria have a decisive influence through their action upon nutrition (obesity) and the immune system (inflammatory bowel disease). The interaction and the symbiosis between humans and their bacterial communities (intestinal flora) is very wide ranging and has particular importance in various physiological aspects, such as immune response, fat metabolism and the production of new blood vessels.
The microbiome is the group of microorganisms (e.g. bacteria and yeast) which live “inside” and “with” a human being, in such a way that their genes and biological activities contribute to health and illness. In absolute numbers, it is said that the human intestine is populated by ten million million bacteria.  This means that ten times more bacteria exist in our intestine than there are cells in our bodies. The human microbiome is unique to each of us and includes more than 1,000 different species of microorganisms.
If one thinks about the magnitude of the microbiome it is not difficult to imagine that there is clear evidence for its involvement in specific diseases, such as in inflammatory bowel disease. To be able to re-establish lost flora or incorporate the flora necessary to maintain the fine balance between the intestinal mucous membrane and the exterior could be key in the design of new treatments for inflammatory bowel disease.
The research demonstrated, for the first time, that the composition of the intestinal flora can be modified. It also proved that it is possible to introduce new species through a donor’s intestinal flora. The study contributed yet another piece of evidence: contrary to previous thinking, the introduction of new species does not necessitate the prior elimination of existing bacteria by use of antibiotics. Moreover, the study determined that the pre-transplant administration of these antibiotics does not facilitate better adaptation of the introduced flora.
Roderic Guigó, from the Centre for Genomic Regulation (CRG) in Barcelona, contributed to the research through the bioinformatic analysis of the metagenome data.
Reference: Manichanh C, Reeder J, Gibert P, Varela E, Llopis M, Antolin M, Guigo R, Knight R, Guarner F.  “Reshaping the gut microbiome with bacterial transplantation and antibiotic intake.” Genome Res, doi:10.1101/gr.107987.110.