OCT 13, 2018 5:35 PM PDT

Gut Bacteria Connected to Heart Transplant Success - or Failure

WRITTEN BY: Carmen Leitch

The trillions of microbes that live in our gastrointestinal tract have been connected to many different aspects of health, and now researchers have found that the gut microbiome influences whether the body can accept a heart transplant. The University of Maryland School of Medicine (UMSOM) scientists established a causal relationship between heart transplant outcome and specific gut microbes. This work could have a significant impact on how transplant rejection is treated. The findings have been reported in the Journal of Clinical Investigation Insight.

This photomicrograph depicts the Gram-positive bacterium, Bifidobacterium eriksonii / Credit: Photo courtesy of Public Health Image Library, CDC/ Bobby Strong

"From our previous work we suspected that the microbiome might have an effect on how transplanted organs are accepted," said one of the study leaders, Emmanuel Mongodin, an associate professor of microbiology and immunology at the UMSOM Institute for Genome Sciences. "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 immune system connects the bacterial species that live in the gut to a heart transplant. The microbiome has been shown to have an important influence on immunity. Gut microbes can actually defend us from pathogens themselves, but they also have a balancing effect that keeps the immune system tolerant of good tissue while it's still able to act against harmful invaders. The gut bacteria can stimulate signals that turn inflammation levels up or down; those signals can, therefore, have a significant impact on whether the body tolerates an organ transplant.

Organ rejection still presents a major hurdle to the success of transplants. Although a lot of effort has gone into trying to reduce organ rejection rates, there has been little to no reduction of long-term reduction rates. This work, however, has shown that some species of microbes can change whether and when rejection occurs.

Study co-leader Jonathan S. Bromberg, a professor of surgery, microbiology and immunology at UMSOM has been working on transplants for many years. He is very familiar with organ rejection, and several years ago, began to think the microbiome may exert an effect on it.

"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."

The researchers used an animal model to show that changes in the microbiome affected the success of a heart transplant. They were able to show which particular species were beneficial, and which ones were harmful to the transplant. Strains of bifidobacterium, for example, appeared to be anti-inflammatory in nature and promoted good outcomes. 

The scientists suggested that these results may hold true for other transplanted organs as well, such as the kidneys. They plan to continue this work to investigate the mechanisms underlying these impacts. It may then be possible to develop therapeutics that can work through those same mechanisms.

Many researchers are trying to learn more about how gut microbes influence different aspects of heart health. The video above describes a project at the University of Toledo that is looking at how the gut microbiome affects blood pressure.


Sources: AAAS/Eurekalert! Via UMSOM, Gut Microbes, Journal of Clinical Investigation Insight

About the Author
  • Experienced research scientist and technical expert with authorships on 28 peer-reviewed publications, traveler to over 60 countries, published photographer and internationally-exhibited painter, volunteer trained in disaster-response, CPR and DV counseling.
You May Also Like
NOV 25, 2019
Drug Discovery & Development
NOV 25, 2019
Darobactin: Promising New Drug to Combat Antibiotic Resistance
Every year, around 700,000 people are estimated to die from drug-resistant infections thanks to our overuse of antibiotics both in agriculture and medicine...
DEC 15, 2019
Microbiology
DEC 15, 2019
Potential Therapeutics for Nipah Virus Are Identified
The fatality rate of Nipah virus has an estimated range of 40 to 75 percent...
DEC 29, 2019
Microbiology
DEC 29, 2019
Coral Reef-Building Organisms Capture First Place in Small World Competition
The winner of the Nikon Small World in Motion contest has captured a tiny animal called coral polyp as light levels go down and it emerges....
JAN 30, 2020
Microbiology
JAN 30, 2020
25% of Antibiotic-Resistant Bacteria Can Spread Resistance Directly to Other Microbes
This research also suggests that antibiotics do not increase the rate at which bacteria acquire drug resistance genes....
FEB 10, 2020
Immunology
FEB 10, 2020
Measles infections can give the immune system amnesia
The immune system detects the presence of invading microbes that it recognizes from previous infections, and initiates a full-blown immune response. New re...
FEB 05, 2020
Technology
FEB 05, 2020
Portable Device Detects Food-borne illness
 Foodborne illnesses kill 3,000 people on an annual basis. According to the Centers for Disease Control and Prevention, an estimated 48 million people...
Loading Comments...