Bacteria found leaking from gut to body in people who are obese
Bacterial DNA has been found in the blood, liver and fat of obese people, showing that fragments of bacteria or whole live bacteria are seeping into their bodies from their intestines, which should not be happening.
Bacterial fragments in the bodies of obese people
"Even fragments of bacteria can trigger an immune response," says André Marette of the Heart and Lung Research Institute of Quebec, Canada.
In obese people, the intestinal barrier is more fragile, explains Marette, allowing fragments of bacteria or live bacteria to enter the body. This could contribute to the development of diabetes by causing inflammation in organs such as the liver. We know that obesity increases the risk of type 2 diabetes.
To study the issue, Marette and her colleagues analyzed blood, liver and fat samples taken from people who have undergone weight-loss surgery. The team took many precautions to exclude bacterial contamination, which would have compromised the results.
The researchers were surprised to find bacterial DNA in all three types of samples. "I never thought that bacterial fragments could actually reach these organs," says Marette.
The type of bacteria varied by tissue
They also found a wide range of bacterial DNA, some of which comes from bacteria known to cause disease, some of which are considered beneficial - at least in the gut - and some of which live in the soil or water rather than in our bodies. "This surprised us a lot," says Marette. The study also found that the type of bacteria varied from tissue to tissue and between people with and without type 2 diabetes.
Because the researchers only looked for the presence of bacterial DNA, they can't tell whether the DNA came from live bacteria or from fragments of dead bacteria. Live bacteria can cause life-threatening infections when they enter the body, but none of the people tested showed signs of this. Marette plans to try growing bacteria from such tissue samples in future studies to see if they are alive or not.
New treatments for bacteria
If the leakage of bacteria into the body really does play a role in the development of diabetes, new treatments could be developed, says Marette. For example, there may be ways to make the intestines less leaky or to kill the bacteria that cause these diseases.
