With no previous microbiome studies of American Indian tribes, a University of Oklahoma-led research team collaborated with the Cheyenne and Arapaho tribes on a three-year study to establish a baseline of information related to the microbiome and American Indian health. The study confirmed that population-focused studies of the microbiome are much needed, particularly for under-represented groups, such as tribal populations.
Cecil M. Lewis, Jr., associate professor in the Department of Anthropology, OU College of Arts and Sciences, says many under-represented groups have pronounced health disparities. Several American Indian groups in Oklahoma, for example, have a high prevalence of obesity, diabetes and autoimmune disorders. These same disorders happen to be among the primary biomedical studies that have popularized human microbiome research.
"Populations, such as tribal communities, that may most benefit from future microbiome interventions are also among those underrepresented within microbiome studies. In some respects, this lack of representation results from the challenge of protecting participants within these historically disadvantaged communities, such as concerns over stigmatization. For three years, we collaborated with the Cheyenne and Arapaho to discuss these topics and identify common ground for the research process. This included discussions of our microbiome data," says Lewis.
Notable about the microbiome study was the metabolite profile of the participants. This profile had features similar to those observed in clinical cases of inflammatory bowel disease. Inflammatory disorders are among the major health disparities observed within some American Indian groups, but the study was not designed to target people with inflammatory disorders. Thus, seeing this pattern in what was essentially a biodiversity study was surprising.
The information obtained from metabolites in combination with the metagenome data was particularly promising. Over 500 metabolites were characterized from all major metabolic pathways and compared to the associated metagenome. In this study, researchers observed biological connections between members of two specific bacterial families and certain metabolic pathways, which helps to build a bigger picture of the biological system that underlies microbiome variation.
"The difference in gut microbes of the American Indians may be the result of social practices and the built environment rather than specific connections to a person's genetic ancestry. In other worlds, I don't believe the microbiome pattern resulted from the genetics of the American Indian. It is likely related to the socioeconomic challenges and resource availability in these rural areas of Oklahoma," says Lewis.
Given that there were clear microbiome differences between the Cheyenne and Arapaho participants living in rural Oklahoma, and non-native individuals living in the city of Norman, Oklahoma, Lewis believes that human microbiome research needs a larger human biological diversity project--one that characterizes microbiomes in a broad range of human practices, cultures and ethnicities. He maintains that such a project needs to be population/community focused and involve active recruitment of under-represented groups.
While such a project may include peoples from unique or extraordinary living conditions, such as hunter-gatherers within developing countries, he noted there was still much to do within his own backyard of Oklahoma. An article on this research has been published in the Cell Press journal Current Biology on December 3. This research was primarily supported by the National Institutes of Health. For more information about this research, contact Lewis at firstname.lastname@example.org.