Summary: New research has identified a promising therapeutic target to prevent dangerous cardiovascular and metabolic complications associated with obstructive sleep apnea. The study shows that gut microbes change bile acids, and those modified bile acids influence disease pathways systemically.
Using genetically engineered mouse models, investigators found that deleting a specific bile acid sensor—the farnesoid X receptor (FXR)—markedly reduced the formation of fatty arterial plaques and preserved gut microbial and metabolic stability in conditions that mimic sleep apnea.
Key Facts
- Sleep apnea and altered bile chemistry: Obstructive sleep apnea causes repeated interruptions in breathing that lower tissue oxygen and raise carbon dioxide. These chronic changes to oxygenation alter bile acid composition, converting some bile acids into pathogenic signaling molecules that circulate in the bloodstream.
- FXR identified as a driver: The host bile acid receptor FXR, which responds to circulating bile acids, was shown to be a central mediator of atherosclerosis progression in the mouse model of sleep apnea. Activation of this receptor appears to promote fatty plaque accumulation in large arteries.
- Genetic knockout approach: The team compared conventional atherosclerosis-prone mice (ApoE knockouts) with mice lacking both ApoE and the FXR receptor (ApoE/FXR knockouts) to isolate FXR’s contribution to disease.
- Marked reduction in arterial plaque: Under simulated sleep apnea conditions, mice without FXR developed far fewer fatty plaques in major systemic vessels, notably the aorta and aortic arch, indicating protection against sleep apnea–related vascular damage.
- Stabilized microbiome and metabolome: Loss of FXR also blunted sleep apnea–driven disruptions in the gut microbiome and fecal metabolite profiles, suggesting a link between microbial bile acid modification and host receptor signaling.
- Localized pulmonary exception: Despite broad vascular protection, fatty plaques persisted on the pulmonary artery, pointing to vessel-specific mechanisms and indicating that FXR is not the sole pathway driving all vascular damage caused by sleep apnea.
- Next steps toward prevention: The research team at UC San Diego plans to compare these findings with human datasets and to pursue follow-up trials testing whether defined probiotics or targeted bile acid supplements can be used preventively to lower cardiovascular risk in patients with sleep apnea.
Source: American Society of Microbiology
Studies in mice suggest a new approach for treating and preventing life-threatening cardiovascular complications in the millions of people affected by obstructive sleep apnea worldwide.
Presented at ASM Microbe 2026, the study details how microbial modification of bile acids alters host signaling and contributes to the heart and metabolic consequences of sleep-disordered breathing.
Obstructive sleep apnea is a common condition in which repeated pauses in breathing during sleep deprive tissues of oxygen and allow carbon dioxide to build up. Those repeated oxygen fluctuations have wide-reaching effects on physiology, including changes to bile acids—molecules produced by the liver, stored in the gallbladder, and released into the intestines to aid fat digestion.
Beyond digestion, bile acids act as circulating chemical signals that bind to receptors throughout the body. Prior work from this group showed that gut microbes can modify bile acids and that these microbial metabolites influence the extent of atherosclerosis observed at the end of experiments. Because bile acids enter the bloodstream, microbially altered bile species can reach distant tissues and alter cellular behavior.
To probe which host receptors are critical for this signaling, lead author Celeste Allaband, DVM, Ph.D., and colleagues focused on FXR. They studied two groups of genetically modified mice: ApoE knockouts that are predisposed to atherosclerosis, and ApoE/FXR double knockouts that lack the bile acid receptor as well as being prone to heart disease. Both groups were exposed either to normal air or to sleep apnea–like conditions that reproduce the intermittent hypoxia of the human disorder.
Throughout the experiment the team sampled feces to track gut microbes and metabolites, and at the study’s conclusion they measured fatty plaque burden across major blood vessels. The results were clear: mice lacking FXR developed significantly fewer plaques in systemic arteries such as the aorta and aortic arch, and their gut microbiome and fecal metabolite profiles showed less disruption from sleep apnea conditions.
“Our findings indicate that microbially modified bile acids signaling through FXR are key contributors to the vascular and metabolic impact of sleep apnea in this mouse model,” Allaband said. “Removing FXR reduced plaque development in important arterial regions and protected the gut ecosystem from sleep apnea–induced disturbances.”
The persistence of plaques on the pulmonary artery despite FXR deletion highlights that distinct vascular beds can respond differently to the same systemic insult, and that additional mechanisms remain to be identified.
Looking ahead, the investigators plan two parallel lines of follow-up: mining human clinical datasets for similar bile acid–receptor patterns, and testing whether administering specific bile acids or probiotic strains can prevent or mitigate disease in preclinical models. Those translational steps will help determine whether targeting bile acid signaling can become a strategy to lower cardiovascular risk in people with obstructive sleep apnea.
Key Questions Answered:
A: Bile acids serve as systemic signaling molecules. Intermittent low oxygen from sleep apnea changes their composition; these altered bile acids circulate and bind receptors in the cardiovascular system, triggering biological responses that promote fatty plaque buildup in arteries.
A: Deleting FXR greatly reduced the formation of dangerous arterial plaques in key systemic vessels. Without FXR, the harmful signals from modified bile acids could not drive the same level of plaque accumulation, and the gut microbiome was less disrupted by sleep apnea conditions.
A: No. The protection is vessel-specific. While FXR deletion shielded the aorta and aortic arch, fatty plaques remained on the pulmonary artery, indicating other pathways contribute to vascular damage in some locations.
Editorial Notes:
- This article was edited by a Neuroscience News editor.
- The underlying journal paper was reviewed in full for accuracy.
- Additional context and clarifications were added by editorial staff.
About this sleep and cognition research news
Author: Joanna Urban
Source: American Society of Microbiology (ASM)
Contact: [email protected]
Image credit: Neuroscience News
Original Research: Findings presented at ASM Microbe 2026