Among other things, the research team from the Institute of Clinical Molecular Biology (IKMB) headed by Professor Andre Franke finds a previously unknown connection between genetic variations responsible for blood type and the occurrence and frequency of certain types of bacteria. The researchers published their results today in the renowned journal Nature Genetics as part of the Collaborative Research Center (CRC) 1182 "Origin and Function of Metaorganisms".
"We made the most interesting observation in the context of the genetic factors responsible for the expression of the blood group antigens in humans," emphasizes first author Dr Malte Rühlemann, scientist at the IKMB and member of the CRC 1182. "These genes responsible for the ABO blood group system determine which blood type a person belongs to. In some people, so called ‘secretors’, these blood group antigens are not only formed on the surface of red blood cells but are also released into the intestine. These are mainly sugar residues, which can possibly be used as an energy source by some bacteria of the Bacteroides group, making these occur more frequently. Particularly in people with blood groups A, AB or B, this mechanism thus seems to directly promote the occurrence of these bacteria in the human intestine," Rühlemann continues.
This correlation potentially has great significance for health, because in about 20 percent of the world's population belonging to the group of ‘non-secretors’ as well as in people with blood group 0, these complex sugars are not secreted, consequently leading to a deviating microbial composition in the intestine. "These metabolites appear to be important molecules in the interaction between host and various microorganisms", explains Rühlemann, who is also a researcher in the "Precision Medicine in Chronic Inflammation" (PMI) Cluster of Excellence. "Previous studies could show that people without this secretion pathway are better protected against norovirus infections, for example," Rühlemann continued. In the working group of CRC1182 member and co-author Professor John Baines at Kiel University’s Institute of Experimental Medicine, these metabolic pathways have been intensively researched for several years.
The example illustrates the effects that individual genetic variation has on human metabolism and can thus help determine the composition of the microbiome. In the future, the researchers try to better understand the mechanisms on which this interaction between humans and microorganisms are based in detail. On a larger scale, the new results of the Kiel research team provide further explanations for the formation of the human microbiome as a whole: in addition to environmental and nutritional influences, the genetics of the human host is apparently also a central factor influencing the bacterial colonization of the body. Thus, the microbiome would be more than a random collection of microorganisms available in the environment.
MEDICA-tradefair.com; Source: Christian-Albrechts-Universität zu Kiel
