Tossing and turning all night is enough to make you feel tired and cranky the next day – but USF Health researchers say sleep deprivation creates additional problems for your gut, immune, and heart health. Especially when combined with a high-fat diet, lack of sleep may trigger low-grade chronic inflammation that could lead to heart disease.

How’s that for a worry to keep you up at night?

In a new paper published in April in The FASEB Journal, the journal of the Federation of American Societies for Experimental Biology. a team of USF Health researchers address not only the relationship between diet and sleep, but the effect on the body’s defense system, including immune health and the microbiome.

The microbiome is made up of the bacteria, viruses and other microorganisms in the gut. Scientists are just beginning to realize that the makeup of the microbiome – whether it contains “good” or “bad” bacteria and other organisms – is greatly influenced by diet and has far broader impacts on human health than previously realized.

“The combination of a high-fat diet and sleep deprivation messes up the immune system,’’ said Ganesh Halade, Ph.D., lead author of the paper and an associate professor at the USF Health Heart Institute. “And when we review the status of the microbiome, then we have a better understanding of the root cause of chronic inflammation that can fuel cardiac failure.’’

Dr. Ganesh Halade

Researchers also studied the lipidome, which is the fats, oils, and their molecules inside the body.

It is well-known that a lipid-dense diet can lead to weight gain and low-grade chronic inflammation. But sleep also is key, being fundamental to heart health and fitness of the immune system. Because more and more people with “sleep fragmentation’’ are facing cardiovascular and cardiometabolic issues including obesity and diabetes, their condition has become a serious medical issue, the researchers report.

“Diet, sleep, and exercise – It’s all related, fundamental, and integrative,’’ Dr. Halade said. “If diet and sleep aren’t in balance, then you invite the array of diseases.  Low-grade chronic inflammation is a by product of imbalanced lifestyle. We know a lot about eating habits, but the real question we need to know more about is the interaction of sleep with diet and effect on immune and heart health.’’

This question has become increasingly important, given that the COVID-19 pandemic, working from home and long hours in front of computer screens have changed the way millions of people sleep. This has led to “a metabolic public health problem’’ due to the disruption of circadian cycles.

Heart disease has been the No. 1 cause of death in the United States every year since 1950.

Other USF Health researchers who worked on this study were: Yusuf Mat, MD, biological scientist; Shalini Jain, PhD, assistant professor, Department of Neurosurgery and Brain Repair; Hariom Yadav, PhD, associate professor, Internal Medicine and Neurosurgery and director of the USF Center for Microbiome Research; and Vasundhara Kain, PhD, senior researcher.

In their study, the researchers used male mice in randomized groups, with one group consuming a fat-rich diet and experiencing interrupted sleep patterns. Researchers measured the microbiome and lipidome in obese, sleep-deprived mice and analyzed gut germs and lipids. To determine the importance of sleep in the context of obesity, mice ate types of fat present in ultra-processed food products and then stayed awake before experiencing cardiac episodes.

Previous reports from Dr. Halade’s lab confirmed that omega-3 fats (fish oil-derived molecules) helped repair the heart in healthy mice after heart attack injuries, with the immune cells of the spleen, molecules called resolution mediators, making the repairs.  However, production of these molecules failed in the spleens of obese and sleep-deprived mice, and heart repair thus failed.  Furthermore, the researchers noted, omega-6 fats present in processed and packaged food products deplete omega-3 fatty acids in plasma and the heart, which causes low-grade chronic inflammation.

Dr. Halade and the team concluded that obesity and poor sleep patterns can lead to immune suppression and limits the body’s ability to repair a heart under stress or injury because prolonged chronic inflammation interferes with immune host defenses.

Dr. Halade is a cardiovascular research scientist working to better understand how inflammation and immune responsive metabolic dysregulation contributes to ischemic and non-ischemic heart failure. At the USF Health Heart Institute, he collaborates with other researchers, including Drs. Siddabasave Gowda B. Gowda and Shu-Ping Hui from Hokkaido University in Japan, on therapies and potential cures for people with heart problems.

— Story by Kurt Loft for USF Health News 

Countless people in the United States suffer from a condition called “leaky gut,’’ where the lining of the intestines becomes porous enough to allow toxins to seep through it and into the bloodstream.

Many are unaware of their condition, or that it can lead to serious health problems, such as chronic inflammation, type 2 diabetes, heart disease, dementia and even some types of cancer. The condition also can cause a variety of unpleasant gastrointestinal syndromes, such as indigestion, gas, bloating, abdominal pain and diarrhea.

In a new paper published in Gut, a leading high-impact international journal in gastroenterology and hepatology, USF Health researchers describe how the right balance of bacteria can deter leaky gut – and how the wrong mix can threaten a person’s health.

The study addresses how leaky gut can accelerate the progression of diabetes in overweight people, and how selective probiotics work to reduce that risk.

People with meat-rich diets are especially vulnerable, said Hariom Yadav, Ph.D., senior author of the study and director of the USF Center for Microbiome Research, Microbiomes Institute, and associate professor of Neurosurgery and Brain Repair.

Hariom Yadav, PhD

“We describe the unique role of the microbiome as a garbage cleaner of our body and our diet’s byproducts, such as how a meat-enriched diet increases the garbage in our gut that changes the microbiome,’’ he said. “This creates leaky gut and inflammation that ultimately induces diabetes.’’

The microbiome is the collection of microbes − bacteria, fungi, and viruses − that naturally live on our bodies. The balance of these tiny organisms can enhance or impair the body’s metabolic and immune functions.

Because everyone’s gastrointestinal tract is selectively porous, many of these organisms – along with nutrients − travel into the bloodstream. However, a person with increased intestinal permeability has too much “leakage,” allowing larger molecules into the bloodstream, creating inflammation. This inflammation impacts many organs in the body, potentially changing their normal functions if exposed for long periods of time and increasing the risk for developing such diseases as diabetes.

“These toxins keep circulating back and forth in our bodies and cause serious health problems,’’ Dr. Yadav added. “We wanted to know how these microbes work in the cleaning process, how they serve as garbage cleaners to remove toxins.’’

The new study discovered that leaky gut in both overweight people and mice diminished the microbiome’s capacity to metabolize a chemical called ethanolamine, a chemical found in beef and other animal food products. High levels of ethanolamine lead to increased permeability of the gut wall, and as a result, more proinflammatory molecules are released into the bloodstream.

Because ethanolamine is found in bovine muscle, people with diets heavy in beef ingest higher-than-normal levels of the chemical than people who eat meat less frequently.

“It’s an intrinsic part of animal meat,’’ Dr. Yadav said of ethanolamine. “So, eating a heavy meat diet contributes more of this chemical, and if the (probiotic) bacteria that metabolizes ethanolamine isn’t there to fight it, those people will be more likely to have leaky gut.’’

If ethanolamine-metabolizing bacteria are low or absent, then the accumulated ethanolamine acts on epithelial cells to cause leakiness. To counter this, the researchers suggest a novel probiotic therapy that would reverse elevated gut permeability, inflammation and dysfunction of glucose metabolism.

“What’s important is to know what kind of bacteria is in our gut and whether it can clear ethanolamine,’’ Dr. Yadav said. “Normally, people talk about what the microbiome produces, but in this study, we talk about what the microbiome utilizes or eats, and how it clears up all these toxins which either comes from our body or from diet. The therapy is where we put back these helpful bacteria in gut, and we can do this with oral probiotics therapy.’’

Dr. Yadav hopes this original research will benefit medical practitioners and policy makers in making better decisions on dietary guidelines.

Dr. Yadav has several ongoing research projects focused on the microbiome. Last year, he received a grant from the National Institute on Aging to help determine if a common medication can restore microbiome diversity in older patients who have a form of heart failure. Results of his three-year study could help prevent the subsequent problems that tend keep these patients inactive and cause their conditions to worsen. He also is working on another study funded by Florida Department of Health, called the Microbiome in Aging Gut and Brain (MiaGB) study, which focuses on how the microbiome impacts brain health, and teaches what to eat and avoid to keep the brain healthy during aging.

Armed with more knowledge about how the microbiome affects inflammation, type 2 diabetes, cardiovascular complications, dementia and even cancer, USF Health researchers hope to identify high-risk patient populations that could benefit from next-generation therapies. Rather than a general treatment, these people might receive more personalized care based on their microbiome and a leaky gut.

— Story by Kurt Loft for USF Health News; photo by Allison Long | USF Health  

Hariom Yadav focuses on microbiome’s role in the gut-brain axis, including creating fermented foods, probiotic mixtures, and modified diets to regulate gut “leakiness”

Hariom Yadav, PhD, is on the frontier of exploring the connection between the microbes in our gut and our brain health – including the impact on age-related cognitive decline and moods.

Dr. Yadav, an associate professor of neurosurgery and brain repair, was recruited to the USF Health Morsani College of Medicine to direct the Center for Microbiome Research, a key component of the newly launched USF Institute for Microbiomes. When he joined USF Health this April from Wake Forest School of Medicine in North Carolina, he brought more than $4 million in research awards from the National Institutes of Health and the U.S. Department of Defense.

“The major focus of our laboratory is investigating whether and how a leaky gut caused by disturbances in the gut microbiome contributes to the risk of dementia and other age-related chronic diseases such as diabetes, cardiovascular disease, and cancer,” Dr. Yadav said. “We also work to develop evidence-based products — probiotics, prebiotics, fermented foods, modified ketogenic diets — that can modulate the microbiome to help prevent bad effects of abnormal leakiness in the gut.”

The human body’s largest population of microorganisms lives in the intestinal tract, numbering in the trillions. These communities of microbes, mainly various strains of bacteria and to a lesser extent fungi and protozoa, are collectively called the gut microbiome. Unique to each individual, the gut microbiome performs various functions, including helping to digest food, control glucose metabolism and nutrient storage, boost the immune system, and moderate inflammatory responses.

Some gut microbes are beneficial, and others can be harmful. If the bugs coexist in harmony – for instance, without a potentially disease-causing strain of bacteria overgrowing and monopolizing the food of useful bacteria – then the digestive tract functions normally, Dr. Yadav said. “A healthy gut microbiome is characterized by a diverse, balanced collection of microorganisms.”

Hariom Yadav, PhD, associate professor of neurosurgery and brain repair at USF Health, stands in front of the anerobic chamber used to grow bacteria under oxygen-free conditions that mimic the gut. He was recently recruited to direct the USF Center for Microbiome Research | Photo by Allison Long, USF Health Communications

Our diet plays the predominant role in determining gut health. Lifestyle factors like exercise, sleep, stress, or the use of antibiotics and other medications, can also alter the gut microbiome’s composition.

Using modern genetic sequencing to precisely characterize the genetic makeup of microbes, scientists like Dr. Yadav have begun to unlock how the gut microbiome works and its massive implications for health and disease.

What does a “leaky gut” mean?

A “leaky gut,” also known as increased intestinal permeability, happens when the mucosal barrier lining the intestines becomes structurally and functionally damaged. That impairs this natural barrier’s ability to prevent infection and maintain general health.

As people age, Dr. Yadav explained, the mucus barrier of the bowel walls thins and becomes more porous than usual, making it easier for harmful bacteria and other toxins to pass from the intestines into the blood and circulate to other organs, including the brain. The microbiome of older guts also has diminished capacity to remove undigested food particles and to clear dead epithelial cells shed from the gut lining to make way for new ones, which contributes to leakiness, he said.

Dr. Yadav and assistant professor Shalini Jain, PhD, (front right) with members of their  research team. | Photo by Allison Long

Alzheimer’s disease and other dementias are among the growing number of medical conditions linked to imbalance in the gut bacteria, known as gut dysbiosis.

A preclinical study by Dr. Yadav and colleagues, published in JCI Insight, showed that the gut microbiomes of older mice were associated with chronic inflammation stimulated by increased gut leakiness via disruption of the intestine’s mucus barrier. The same study indicated that a human-derived probiotic “cocktail” mixing strains of bacteria isolated from healthy infant guts could suppress gut leakiness and improve both the metabolic and physical functions in older mice.

Probiotics are usually live bacteria that, when consumed in appropriate amounts, interact beneficially with other bacteria present in the human gut. Another study by Dr. Yadav’s team, published in GeroScience, found that a probiotic does not need to be alive to confer health benefits. The researchers discovered that a probiotic strain of Lactobacillus paracasei D3.5, even in its heat-killed or inactive form, decreased leaky gut and inflammation and improved cognitive function in older mice. This technology is under commercial development with the Postbiotics Inc., a N.C. biotechnology company cofounded by Dr. Yadav.

Brandi Miller (right), a PhD student, with Dr. Yadav and Dr. Jain. | Photo by Allison Long

Emerging research defining how gut microbiome abnormalities lead to leaky gut and harmful inflammation holds great promise for treating a growing number of age-related diseases. But interactions between the gut microbiome, its human host, and the outside environment are very complex.

The science is in its early stages, Dr. Yadav emphasized. “We still need to prove whether the long-term inflammation triggered by a leaky gut (causally) contributes to Alzheimer disease, cognitive decline or other age-related conditions in people at high risk.”

The gut-brain connection

The human gut contains as many nerve cells as the brain, and in some ways serves as a “second brain,” Dr. Yadav said. That’s because the intestines and the brain can send neuronal signals back and forth directly through a circuit known as the gut-brain axis.

.

This bidirectional gut-brain communication can affect processes like how hungry we feel, how much food we eat, how individual food tastes differ, and whether certain foods upset our stomach. Studies have also begun to unravel how the gut microbiome may affect executive brain function, including its influence on depression, anxiety and cognition.

Several gut bacteria make neurotransmitters, including serotonin and dopamine – two chemical messengers linked to mood and mental health. The “gut neurons” can shoot these neurotransmitters to the brain through the gut-brain axis and the mood-modifying chemicals can also be released into circulating blood, Dr. Yadav said.

Research in mice and humans indicates that the high-fat, low carbohydrate ketogenic diet is a powerful regulator of brain function, improves Alzheimer’s disease pathology, and alters the gut microbiome.

With that in mind, an earlier pilot study led by Dr. Yadav and colleagues reported that specific harmful fungi interacting with bacteria in the guts of older patients with mild cognitive impairment (which increases the Alzheimer’s disease risk) can be beneficially changed by eating a modified ketogenic diet. The research appeared last year in the Lancet journal EBioMedicine.

PCR-amplified DNA used to study microbiome-sensing mechanisms. | Photo by Allison Long

Supported by a National Institute on Aging grant, Dr. Yadav’s team is now working to distinguish the gut microbiomes of those who respond to a modified ketogenic diet, versus the microbiomes of non-responders. The researchers want to determine exactly how the gut microbiome promotes the metabolic action of the modified ketogenic diet to possibly reduce age-related cognitive decline and Alzheimer’s disease.

“Our goal is to identify alternatives that can either supplement this ketogenic diet or mimic the diet’s effect on the gut microbiome (in non-responders) to improve brain health,” Dr. Yadav said.

Dr. Yadav’s laboratory plans to launch a Microbiome in Aging Gut and Brain (MiAGB) clinical study led by assistant professor Shalini Jain, PhD. The investigators will collect clinical samples (stool, blood, cerebrospinal fluid) from people age 60 and older with no age-related cognitive decline as well as those diagnosed with mild cognitive impairment (MCI) and dementia. They will track alterations in the gut microbiomes of healthy older adults over time to see if certain biomarkers can accurately predict, early in the disease process, which individual are most likely to develop MCI or dementia.

.

Baby poop: A source of beneficial probiotics?

With a project he calls “Foods for Mood,” Dr. Yadav aims to identify microbial therapies to create a more balanced, varied gut microbiome — both to help maintain overall health as we age and to prevent or delay Alzheimer’s disease and other forms of dementia.

The probiotic strains his laboratory tests and refines as potential biotherapeutics come from a readily available source: baby poop. “Babies are usually pretty healthy and clearly do not suffer from age-related diseases,” Dr. Yadav said.

Using fecal samples from the diapers of infants, his team follows a rigorous protocol to isolate, purify and validate the safety of those strains of microbes most promising for promoting gut health. These probiotics (health-promoting bacteria), prebiotics (primarily fiber substances that the beneficial bacteria eat) or synbiotics (combinations of prebiotics and probiotics) are being incorporated into prototype high-fiber or fermented foods like yogurts, milk, or butter. The laboratory-grown strains need to be tested in clinical trials and follow the regulatory path to be commercialized as food products before they appear on supermarket shelves.

The “Foods for Moods” project led  by Dr. Yadav includes incorporating probotics, prebiotics and synbiotics into high-fiber and fermented food products. | Photo by Allison Long

The bacterial strains in baby feces are particularly good at helping produce short-chain fatty acids (SCFAs), a byproduct of gut microbe digestion that reduces inflammation, Dr. Yadav said. People with diabetes, cancers and age-related illnesses often have fewer SCFAs, and accumulating evidence indicates that the neuropathology underlying Alzheimer’s disease may be partly regulated by SCFAs.

“We are interested in targeting the source of (harmful) inflammation, which we think is the leaky gut. If we can fix that early enough, perhaps we can reduce the risk of chronic inflammatory response-mediated diseases, which mainly develop later in life,” Dr. Yadav said. “A healthy gut absorbs the nutrients we need from foods and supplies them to the body to help prevent age-related diseases and conditions, or to improve their management.”

The synbiotic yogurt developed at USF Health combines strains of prebiotics and probiotics that have been isolated, purified and preclinically validated for safety and effectiveness in promoting gut health. | Photo by Allison Long

Advancing technologies for microbiome research

Dr. Yadav received a PhD in biochemistry from the National Dairy Research Institute, India, in 2006. He conducted postdoctoral training in cell biology and metabolic diseases at the NIH’s National Institute of Diabetes and Digestive and Kidney Disease in Bethesda, Maryland.

Dr. Yadav has published more than 130 peer-reviewed papers and serves on the editorial boards and as a reviewer for several high-impact journals. He speaks frequently to scientific audiences and the media about the role of the gut microbiome and its modulators in age-related disorders, the gut-brain axis, probiotics and other biotherapeutics.

As director of the university-wide Center for Microbiome Research based at USF Health, he organizes technologies to advance microbial studies, including human microbiome/probiotics biorepositories, tools to grow bacteria and perform fecal microbiome transplantation, machines to sequence the genomes of microbes, and bioinformatics pipelines to robustly analyze massive volumes of sequencing data.

The image on the computer monitor depicts the movement of food through mice intestines labeled with a fluorescent dye. | Photo by Allision Long

Something you might not know about Dr. Yadav

Dr. Yadav attributes his interest in gut microbiome research in part to his mother’s severe gastrointestinal reactions to the widely prescribed type 2 diabetes medication metformin. Years later, he discovered that metformin and other drugs interact with microbes in an individual’s gut to influence medication effectiveness and the patient’s drug tolerance.

While metformin does not work for every diabetes patient, Dr. Yadav’s team recently presented findings at the American Physiological Association (APS) Experimental Biology 2021 meeting showing that metformin inhibited the spread of Clostridioides difficile or C. diff — a potentially life-threatening infection commonly acquired during hospital stays.

Dr. Yadav describes himself as a “grower” who enjoys growing flowers, plants and vegetables in his family’s backyard, growing bacteria in the laboratory, and helping his students grow in their scientific proficiency. A vegetarian, he makes his own probiotic-fortified yogurt and smoothies.