More evidence of the importance of a healthy gut microbiome has been discovered as researchers have found a link between gut bacteria and heart transplant failure rates.
Organ rejection is one of the biggest concerns in a transplant situation and doctors from the University of Maryland School of Medicine believe the gut microbiome plays a key role in transplant acceptance.
In a study published in the Journal of Clinical Investigation Insight, researchers said their findings have the potential to dramatically improve transplantation. The research was designed to begin identifying specific bacterial species that can affect whether the transplanted heart is rejected by the body and how soon.
"From our previous work we suspected that the microbiome might have an effect on how transplanted organs are accepted," said one of the study’s authors, Emmanuel Mongodin. "This work clearly shows that there is a connection between these gut microbes and the body's response to the new organ. It's very exciting."
The long-term threshold for the rejection of heart transplants is between five and eight years and a lot of effort has been directed at decreasing the failure rate during that time frame. Unfortunately, researchers have been unable to make much in the way of gains to this point.
The lead study author is Dr. Jonathan Bromberg, a surgeon who has transplanted hundreds of organs. He has first-hand knowledge of the problem of rejection and began looking at variables that may be contributing to the failure. That led him to examine the gut.
"The more I looked, the more it seemed there might be something there," said Dr. Bromberg. "The immune system is deeply intertwined with our gut microbiome, and I wanted to explore this connection in more depth."
Bromberg wondered what impact certain bacterial species might have in the rejection process as some have the ability to trigger pro- or anti-inflammatory responses. These signals can affect how the immune system responds to the transplant.
Bromberg and Mongodin showed they could improve the outcome of a heart transplant in an animal model by focusing on different strains of bacteria. One key strain of bifidobacterium was shown to have an anti-inflammatory effect, which is beneficial to the long-term success.
They believe their research may help with other transplanted organs such as kidneys. The next step for the researchers is to focus on the mechanisms behind the effects.