Gut microbiome plays important role in sleep regulation

Transplanted bacteria from sleep-apnea mice caused sleep changes in recipient mice

September 23, 2020

Science Daily/University of Missouri-Columbia

Obstructive sleep apnea (OSA) is a chronic sleep condition affecting more than one billion people worldwide. Evidence suggests OSA can alter the gut microbiome (GM) and may promote OSA-associated co-morbidities, including diabetes, hypertension and cognitive problems. Researchers from the University of Missouri School of Medicine and MU Health Care have discovered how OSA-related sleep disturbances affect the gut microbiome in mice and how transplanting those gut bacteria into other mice can cause changes to sleep patterns in the recipient mice.

David Gozal, MD, the Marie M. and Harry L. Smith Endowed Chair of Child Health at the MU School of Medicine, said the study shows the gut microbiome plays a major role in sleep regulation. This ultimately could translate into treatments that target the gut microbiome in humans with 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 Gozal, the lead author of the study. "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 study exposed male mice to either room air or intermittent hypoxia -- a condition in which the body doesn't get enough oxygen -- designed to mimic OSA. After six weeks, researchers collected fecal material from all of the rodents. A third group of mice was divided up and given either a fecal transplant from the mice breathing room air or those exposed to intermittent hypoxia. The transplanted mice underwent sleep recordings for three consecutive days. Researchers found the mice who received transplants from the intermittent hypoxia group slept longer and slept more often during their normal period of wakefulness, suggesting increased sleepiness.

"This is the first study that evaluated sleep in naïve mice subjected to a fecal microbiome transplant from mice exposed to intermittent hypoxia," Gozal said. "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."

Emerging evidence suggests the GM can influence health and sleep quality through the brain-gut microbiome axis (BGMA). The next step is to study the mechanism involved in the relationship between the brain and the gut to determine how changes in the gut microbiome can affect sleep structure and, in turn, how OSA can contribute to co-morbidities.

https://www.sciencedaily.com/releases/2020/09/200923124804.htm

Links among poor sleep, high blood pressure, gut microbiome discovered

September 2, 2020

Science Daily/University of Illinois at Chicago

In the first study of its kind, University of Illinois Chicago researchers have found associations among disrupted sleep, elevated blood pressure and changes in the gut microbiome.

The research aimed to determine whether a 28-day period of disrupted sleep changed the microbiota in rats. The gut microbiota refers to the collection of microorganisms living in the intestines. The researchers also sought to identify biological features associated with undesirable arterial blood pressure changes.

The results were published in Physiological Genomics.

Using rats, the researcher disrupted their sleep periods. Rats are nocturnal, so the experiments were designed to interfere with their daytime sleep periods.

Telemetry transmitters measured the rats' brain activity, blood pressure and heart rate. Fecal matter also was analyzed to examine changes in the microbial content.

The research idea was generated by several of the paper's authors who are or have been health care providers with night-shift schedules.

"When rats had an abnormal sleep schedule, an increase in blood pressure developed -- the blood pressure remained elevated even when they could return to normal sleep. This suggests that dysfunctional sleep impairs the body for a sustained period," Maki said.

Undesirable changes also were found in the gut microbiome -- the genetic material of all bacteria living in the colon.

Contrary to her initial hypothesis, Maki found that the gut microbiome changes did not happen immediately, but instead took a week to show unfavorable responses such as an imbalance among different types of bacteria including an increase in microbes associated with inflammation.

"When the sleep disruption stopped, everything did not come back to normal immediately," Maki said. "This research shows a very complex system with the presence of multiple pathological factors."

This was initial research, and studies will continue to examine pathways involving the gut microbiome and metabolites produced by gut bacteria. The researchers will see exactly how sleep characteristics are changed and how long blood pressure and gut microbiome alterations persist. Researchers will then determine how this information translates to humans.

"We hope to find an intervention that can help people who are at risk for cardiovascular disease because of their work and sleep schedules. People will always have responsibilities that interrupt their sleep. We want to be able to reduce their risk by targeting the microbiome with new therapies or dietary changes," Fink said.

https://www.sciencedaily.com/releases/2020/09/200902182439.htm

New study points to another possible correlation between sleep and overall good health

Your gut microbiome and quality sleep are interconnected

October 28, 2019

Science Daily/Nova Southeastern University

As if you didn't already have enough to worry about to keep you up at night, a new study indicates that poor sleep can negatively affect your gut microbiome, which can, in turn, lead to additional health issues.

Great.

That's at the heart -- or gut -- of the study just published in PLoS ONE that involved several researchers from Nova Southeastern University (NSU.) They wanted to see just how much of a connection there is between what is going on in our insides and how that may impact the quality of sleep we experience.

"Given the strong gut-brain bidirectional communication they likely influence each other," said Jaime Tartar, Ph.D., a professor and research director in NSU's College of Psychology who was part of the research team. "Based on previous reports, we think that poor sleep probably exerts a strong negative effect on gut health/microbiome diversity."

What you may be asking yourself right now is: "what in the world is a gut microbiome?" Simply put -- it's all the microorganisms (bacteria, viruses, protozoa and fungi) and their genetic material found in your gastrointestinal (GI) tract. And yes, we all have these in our GI tract, but not all at the same levels (diversity.) As it turns out, it's this diversity that could be the key.

For this study, subjects wore what Tartar called an "Apple Watch on steroids" to bed, which monitored all sorts of vitals. This way the researchers could determine just how well a night's sleep the subjects got, and then they tested the subjects' gut microbiome. What they found was those who slept well had a more diverse -- or "better" -- gut microbiome.

Tartar said that gut microbiome diversity, or lack thereof, is associated with other health issues, such as Parkinson's disease and autoimmune diseases, as well as psychological health (anxiety and depression.) The more diverse someone's gut microbiome is, the likelihood is they will have better overall health.

"We know that sleep is pretty much the 'Swiss Army Knife of health," Tartar said. "Getting a good night's sleep can lead to improved health, and a lack of sleep can have detrimental effects. We've all seen the reports that show not getting proper sleep can lead to short term (stress, psychosocial issues) and long-term (cardiovascular disease, cancer) health problems. We know that the deepest stages of sleep is when the brain 'takes out the trash' since the brain and gut communicate with each other. Quality sleep impacts so many other facets of human health."

Tartar's area of research focuses on the mechanisms and consequences of acute and chronic stress in humans and the impact of normal sleep and sleep deprivation on emotion processing and physiological functioning.

So what determines someone's gut microbiome? According to Robert Smith, Ph.D., an associate professor and research scientist at Nova Southeastern University (NSU) Halmos College of Natural Sciences and Oceanography, who is also a member of the research team, there are a couple of factors that come into play.

One is genetics -- some people are predisposed at a genetic level to have a more diverse gut microbiome than their friends and neighbors. Another factor is drugs -- certain medications, including antibiotics, can have an impact on the diversity of your gut microbiome. He also said that your diet plays a factor as well.

Smith said that their team, which included colleagues from Middle Tennessee State University, examined the association between sleep, the immune system and measures of cognition and emotion. He said understanding how these parts of human physiology work may lead to a better understanding of the "two-way communication" between the person and their gut microbiome, and could lead to novel sleep intervention strategies.

"The preliminary results are promising, but there's still more to learn," Smith said. "But eventually people may be able to take steps to manipulate their gut microbiome in order to help them get a good night's sleep."

https://www.sciencedaily.com/releases/2019/10/191028164311.htm