Scientists discovered a surprising gut-heart connection that may help prevent sleep apnea from causing serious cardiovascular damage.
Sleep apnea affects millions of people worldwide and is known to raise the risk of serious cardiovascular problems. Now, researchers have identified a potential new treatment target that could help reduce some of the condition’s harmful effects. Findings presented at ASM Microbe 2026 suggest that gut microbes and the way they alter bile acids may play an important role in protecting against sleep apnea-related heart and metabolic damage.
How Sleep Apnea Affects the Body
Obstructive sleep apnea is a common disorder in which breathing repeatedly stops and starts during sleep. These interruptions reduce oxygen levels while allowing carbon dioxide to build up, triggering a range of biological changes throughout the body.
Previous studies have shown that low oxygen levels can alter bile acids, compounds produced by the liver, stored in the gallbladder, and released into the intestines to help digest fats. Beyond their digestive role, bile acids also act as signaling molecules that interact with receptors throughout the body.
Researchers had previously demonstrated that gut microbes can modify bile acids, influencing the development of atherosclerosis, the buildup of fatty plaques inside arteries. Because bile acids enter the bloodstream, they can affect tissues and organs far beyond the digestive system.
“We were pretty sure from our previous studies that bile acids, especially microbially modified ones, were a key to regulating the disease so we wanted to know what happens when one of the key receptors for them are missing — does the disease go away?” said study first author Celeste Allaband, DVM, Ph.D. from the University of California, San Diego.
Investigating a Key Bile Acid Receptor
To explore that question, the team studied two groups of mice. One group consisted of mice genetically prone to heart disease, known as ApoE knock-outs. The second group included mice that were also prone to heart disease but lacked a bile acid receptor called the farnesoid X receptor (FXR). These animals are known as ApoE/FXR knock-outs.
Both groups were exposed either to normal sleeping conditions with room air or to conditions designed to mimic sleep apnea. Throughout the study, researchers analyzed gut microbes and metabolites using fecal samples. At the end of the experiment, they measured the amount of fatty plaque that had accumulated in the animals’ arteries.
Fewer Artery Plaques and Less Gut Disruption
“Our study shows that the FXR host receptor, which can be activated or deactivated by bile acids, plays a central role in driving the buildup of fatty plaques in the arteries during sleep apnea-like conditions,” Allaband said. “Strikingly, when this receptor was removed from the mice, the development of arterial plaques dropped significantly in some areas and disruptions to the gut microbiome were minimized.”
The results revealed that mice lacking the FXR receptor developed significantly less plaque in both the aorta and the aortic arch. Some plaque formation still occurred in the pulmonary artery, but the overall burden was reduced. The researchers also observed that sleep apnea-like conditions had a smaller impact on the gut microbiome and the collection of metabolic compounds produced within the body.
“These results tell us that microbially modified bile acids and how they signal through the receptor we knocked out (FXR) seem to be key to the impact of sleep apnea-like conditions in our mouse model. We also identified specific bile acids of interest to explore further,” Allaband said.
Potential Future Treatments
The research team is now pursuing several follow-up studies. One goal is to examine human datasets to determine whether the same biological patterns seen in mice are present in people with sleep apnea.
“We also plan to take some of our key bile acids of interest and see if supplementation of these compounds alone can help prevent or reduce disease,” Allaband said. “We may also take some key microbes of interest and see if they can be given preventively as a probiotic. There is lots of exciting future work to come.”
If similar effects are confirmed in humans, future therapies could potentially target bile acids, the FXR receptor, or beneficial gut microbes to help prevent or reduce the cardiovascular complications associated with sleep apnea.
Meeting: ASM Microbe 2026
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