AsianScientist (Feb. 24, 2016) – Korean and American researchers have discovered that identifying changes in gut microorganism types and activities could help in the early diagnosis of type 2 diabetes (T2D).
The ability to detect changes like this before T2D symptoms develop might be useful for early diagnosis and intervention, providing a new way to potentially reduce the time between detection of T2D and onset of the disease. Their work was published in Genome Medicine.
The research team, from Broad Institute in the US and Seoul National University, South Korea, examined variations in composition and function of the gut microbiota in relation to existing clinical T2D indicators like body mass index (BMI) or fasting blood sugar (FBS), the amount of glucose found in the blood after an overnight fast.
In the present study, the researchers showed that changes in the gut microbiota that can be observed in clinical T2D are already present at sub-clinical and pre-onset stages of the condition.
While imbalances in the gut microbiota have been linked to T2D, previous research only compared cases of those with established T2D to healthy individuals. It was not clear whether changes in the microbiota occur before T2D can be detected with current markers like BMI and FBS.
To find out whether this was the case and to identify links between T2D biomarkers, changes in the gut microbiota, and host genetics, the researchers examined a cohort of 20 identical (monozygotic) healthy Korean twins aged 30-48 years who were enrolled in the Healthy Twin Study in South Korea.
As identical twins share the same genes, they present a unique opportunity to identify aspects of disease linked to gut microorganisms separately from causes due to human genetic variation.
The researchers collected physiological data like age, height and weight; clinical data like BMI and FBS; information on lifestyle and dietary habits; and fecal samples with which to assess microbial community structure.
None of the individuals studied were yet diagnosed with full T2D. However, the wide range of disease markers and the different levels at which they presented—from healthy to near-clinical—enabled the researchers to investigate, for the first time, how the function and composition of the microbial community in the gut vary at different stages before onset of the condition.
Work such as this may also aid our understanding of whether microbial or immune responses are also causal in disease development, which was not a part of this study.
The twin-based design also led to an unexpected finding. While twins had the same species of microorganisms living in their guts, these species were present as different strains.
“It suggests that twins are initially colonized by the same bugs in infancy—due perhaps to shared environment or genetics—and then retain those organisms long enough to begin to diverge through short-term evolution,” said corresponding author Curtis Huttenhower.
“If true, this can be studied directly in larger twin cohorts, and it would help us understand how the microbiome develops beyond diabetes alone in a wide variety of conditions.”
Due to the small sample size of this study, further research needs to be done in larger cohorts to confirm these findings.
The article can be found at: Yassour et al. (2016) Sub-clinical Detection of Gut Microbial Biomarkers of Obesity and Type 2 Diabetes.
Source: BioMed Central; Photo: Shutterstock.
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