HEALTH NEWS

Study Title:

Gut Flora and Impaired Glucose Regulation

Study Abstract

Type 2 diabetes (T2D) is a result of complex gene–environment interactions, and several risk factors have been identified, including age, family history, diet, sedentary lifestyle and obesity. Statistical models that combine known risk factors for T2D can partly identify individuals at high risk of developing the disease. However, these studies have so far indicated that human genetics contributes little to the models, whereas socio-demographic and environmental factors have greater influence1. Recent evidence suggests the importance of the gut microbiota as an environmental factor, and an altered gut microbiota has been linked to metabolic diseases including obesity2, 3, diabetes4 and cardiovascular disease5. Here we use shotgun sequencing to characterize the faecal metagenome of 145 European women with normal, impaired or diabetic glucose control. We observe compositional and functional alterations in the metagenomes of women with T2D, and develop a mathematical model based on metagenomic profiles that identified T2D with high accuracy. We applied this model to women with impaired glucose tolerance, and show that it can identify women who have a diabetes-like metabolism. Furthermore, glucose control and medication were unlikely to have major confounding effects. We also applied our model to a recently described Chinese cohort4 and show that the discriminant metagenomic markers for T2D differ between the European and Chinese cohorts. Therefore, metagenomic predictive tools for T2D should be specific for the age and geographical location of the populations studied.

From press release:

Intestinal bacteria may have a greater influence on us than was previously thought. In a study published in the journal Nature on 29 May, researchers at the Sahlgrenska Academy, University of Gothenburg, Sweden and Chalmers University of Technology, Sweden, show that patients with type 2 diabetes have an altered gut microbiota. Their findings have led to a new model to identify patients at increased risk of developing diabetes.



The human body contains ten times more bacteria than human cells. Most of these bacteria comprise the normal gut microbiota. Our bodies thus contain a vast number of bacterial genes in addition to the genes in our own cells, and are collectively known as the metagenome.

Three Swedish, Gothenburg-based research groups led by Fredrik Bäckhed and Björn Fagergberg, Sahlgrenska Academy, University of Gothenburg, and Jens Nielsen of Chalmers University of Technology compared the metagenome of 145 women with diabetes, impaired glucose tolerance and healthy controls, and showed that women with type 2 diabetes have an altered gut microbiota.

Furthermore, healthy women have higher numbers of gut bacteria known to be producers of butyrate, a fatty acid that has previously been linked to beneficial health effect.

On the basis of these findings, the researchers developed a new model that can distinguish between patients with type 2 diabetes and healthy women by analysis of the metagenome. This model has better predictive value than the classical predictive markers used today, such as body-mass index and waist-hip ratio.

"By examining the patient's gut microbiota, we could predict which patients are at risk of developing diabetes. The big challenge is to find out whether the composition of the gut microbiota promotes the onset of age-related diabetes. If this is the case, this would indicate new opportunities to prevent the disease," says Professor Fredrik Bäckhed.

"In this study, we have developed new methods to analyze the metagenomic data and have been able to exploit much more of the 'unknown' metagenome, that is, the bacteria that have not been previously mapped," continues Jens Nielsen, Professor of Systems Biology at Chalmers University of Technology. "The study is an excellent example of how novel technologies, developed in connection with Chalmers' initiative in life science, can assist in analyzing large amounts of data from the clinic."

Study Information

Fredrik H. Karlsson, Valentina Tremaroli, Intawat Nookaew, Göran Bergström, Carl Johan Behre, Björn Fagerberg, Jens Nielsen, Fredrik Bäckhed
Gut metagenome in European women with normal, impaired and diabetic glucose control.
Nature
2013 May
The Wallenberg Laboratory and Sahlgrenska Center for Cardiovascular and Metabolic Research, Institute of Medicine, University of Gothenburg, SE-413 45 Gothenburg, Sweden