Scholars from Georgetown and Emory universities have gone over previous studies conducted on heart failure and gut biome, and found that patients with heart failure had less biodiversity in faecal samples compared to controls.
A systematic review of research findings has found that some people who experience heart failure have less biodiversity in their gut, or have elevated gut metabolites. Both these conditions are associated with more hospital visits and greater risk of death.
“Living inside every person are trillions of microorganisms — bacteria, viruses, fungi and other life forms that are collectively known as the microbiome. Various organs have distinct microbial inhabitants, but the group that has attracted the most attention in biomedical research is the one in the gut,” Herb Brody writes in Nature.
Researchers recently writing in Heart Failure Reviews point out that “There is an expanding body of research on the bidirectional relationship of the human gut microbiome and cardiovascular disease, including heart failure (HF).”
“Heart disease is the leading cause of death for men, women, and people of most racial and ethnic groups in the United States,” the Centers of Disease Control and Prevention (CDC) warn. Heart failure affects more than six million US residents annually, and is seen as the end-stage of progressive cardiovascular disease.
The researchers analysed seven years of genetic, pharmacologic and other types of research findings from around the world to come up with a wide perspective on how the microbiome can influence heart failure. Their overview focused on one harmful metabolite called trimethylamine-N-oxide (TMAO) that is produced by gut microbiota upon consumption of full-fat dairy products, egg yolks and red meat.
They wrote: “Patients with [heart failure] had less biodiversity in faecal samples compared to controls.”
“To diagnose and manage heart failure we rely on certain findings and test results, but we do not know how poor heart function influences the activities of the gut, including the absorption of food and medications,” says Kelley Anderson, associate professor of nursing at Georgetown and corresponding author of the study.
“There is now an appreciation of a back-and-forth relationship between the heart and elements in the gut, as clearly the heart and vascular system do not work in isolation -- the health of one system can directly influence the other, but clear connections are still being worked out scientifically.”
The researchers went through 511 research articles published between 2014 and 2021 that linked the microbiome with heart failure. Then they sharpened their focus on the 30 most relevant articles.
They were particularly interested in recent studies that made use of more advanced technology, especially those using tools that can closely examine the biological roles of DNA and RNA in the body providing more detailed insights into the gut/heart relationship.
The studies the investigators went over did not provide strong data and as a result, the investigators could not pinpoint the effects of diet on the interplay between the microbiome and the cardiovascular system. The researchers underlined that nutrition is an important component of overall cardiovascular health, so for future research efforts, they recommend exploring the impact of diet in relation to the microbiome.
According to Anderson, who is looking for possible interventions to diminish negative impacts of the microbiome on heart disease, there are ongoing studies that are looking into the use of antibiotics, prebiotics and probiotics, all of which can affect the microbiome, in addition to intestinal binders that catch hold of and help shuttle harmful elements out of the gut.
“We are currently developing a forward-looking study to evaluate the microbiome in patients with heart failure,” says Anderson.
“We are particularly interested in the symptomatic experience of patients with end-stage heart failure as well as disease-related weight loss and wasting during this stage of cardiovascular disease.”