Gut microbiome plays an unexpected role in sleep regulation

A new study from the University of Missouri Columbia has found evidence that the gut microbiome has a powerful influence on sleep. When the researchers transplanted gut bacteria from mice with sleep apnea to healthy mice, the recipients exhibited increased sleepiness throughout waking hours.

Previous studies have shown that obstructive sleep apnea (OSA) may alter gut bacteria in a way that promotes comorbid conditions such as diabetes, hypertension, and cognitive problems.

“Obstructive sleep apnea is a chronic prevalent condition characterized by intermittent hypoxia and sleep fragmentation,” wrote the study authors.”

“Evidence suggests that OSA can alter the gut microbiome diversity and composition that may then promote the occurrence of some of the OSA-associated morbidities.” 

“However, it is unclear whether perturbations in the gut microbiome caused by intermittent hypoxia (IH) can elicit sleep disturbances that underlie the increased sleep propensity that occurs in IH-exposed mice.”

According to study lead author Dr. David Gozal, the research shows that the gut microbiome plays a major role in sleep regulation. This could ultimately translate into therapies that target the gut microbiome in humans to treat OSA.

“By manipulating the gut microbiome, or the byproducts of the gut microbiota, we would be in a position to prevent or at least palliate some of the consequences of sleep apnea,” said Dr. Gozal. “For example, if we combine continuous positive airway pressure (CPAP) with customized probiotics that change the patient’s gut microbiome, we might be able to eliminate some of the tiredness and fatigue and reduce the likelihood of the comorbidities associated with OSA that affect cognition, memory, cardiovascular disease or metabolic dysfunction. If we can do any one of those things, then this is a major movement forward in the way we treat OSA.”

The researchers exposed male mice to either room air or intermittent hypoxia – a condition in which the body does not get enough oxygen. After six weeks, fecal material was collected from all of the animals. 

A third group of mice received a fecal transplant from either the mice breathing room air or those exposed to intermittent hypoxia. This group underwent sleep recordings for three consecutive days. 

The mice who received transplants from the intermittent hypoxia group showed clear signs of increased sleepiness, such as sleeping longer and more often during their normal period of wakefulness.

“This is the first study that evaluated sleep in naïve mice subjected to a fecal microbiome transplant from mice exposed to intermittent hypoxia,” said Dr. Gozal. “The fecal microbiome analysis showed profile differences between the mice transplanted from intermittent hypoxia donor mice versus those exposed to room air, indicating that the transplant altered the GM of the recipient mice.”

There is a growing collection of evidence to suggest that the gut microbiome influences health and sleep quality through the brain-gut microbiome axis (BGMA). Further research is needed to identify the mechanism involved in the relationship between the brain and the gut.

The study is published in the journal Experimental Neurology.

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By Chrissy Sexton, Earth.com Staff Writer