BioQuakes

AP Biology class blog for discussing current research in Biology

Tag: gut microbiome

Taking care of your gut might be a pain now, but is definitely worth it!

Brain with Alzheimer’s

The contributions of microbes to multiple aspects of human physiology and neurobiology in health and disease have up until now not been fully appreciated.
Many people have said the human gut is like a “second brain.” With trillions of microbes, the digestive tract of the human gut can influence many things such as your metabolism, nutrition, immune function, and even your happiness. New research continues to show links between the brain and the health of the gut.

For example, a study from Lund University found that “unhealthy intestinal flora can accelerate the development of Alzheimer’s disease.” Alzheimer’s disease is an extremely common form of dementia or memory loss. It is caused by the death of many brain cells, which progressively decreases the size of the brain and the number nerve cells and connections. This study showed that mice with Alzheimer’s have a different bacterial profile in their guts than mice without this disease. Dr. Frida Fak Hallenius said that “Alzheimer’s is a preventable disease and in the near future we will likely be able to give advice on what to eat to prevent it. Take care of your gut bacteria, by eating lots of whole-grains, fruits and vegetables.”

 

After these discoveries, researchers are looking deeper into how bacteria can affect brain pathology. One of their ideas is that the bacteria may affect T-cells in the gut, which controls inflammatory processes both in the gut and brain. Therefore, if we can find a way to increase the health of the gut, we can reduce inflammation and brain damage. Alzheimer’s, while it is one of the most feared diseases, is preventable to in extent and if not preventable, there are several ways to delay it. The human gut microbiome has a huge impact on your health and your brain’s health. If scientists can continue to discover how to make your gut as healthy as possible, Alzheimer’s could soon be a thing of the past.

http://www.huffingtonpost.com/entry/gut-bacteria-alzheimers_us_589e0e09e4b03df370d628be

http://www.nature.com/news/the-tantalizing-links-between-gut-microbes-and-the-brain-1.18557

Mouse Gut Research Could Save Your Brain

A new study in mice published by Nature Magazine suggests that a specific microbial balance results in a reduction of brain damage after a stroke. The severity of a stroke is determined by two types of intestinal cells: Regulatory T Cells and Gamma Delta T Cells. Regulatory T cells have a helpful inflammatory effect. However, Gamma Delta T Cells make a cytokine which results in harmful post-stroke inflammation.

Researchers at Weill Cornell Medical College and Memorial Sloan Kettering Cancer Center studied two different groups of mice in order to learn if gut cells could be altered in order to reduce stroke severity. One group of mice had gut bacteria that was unaffected by antibiotics, while the other group of mice’s gut bacteria was extremely vulnerable to antibiotics. The group of mice that was vulnerable to antibiotics had a higher ratio of good Regulatory T Cells to harmful Delta T Cells.

House mouse.jpg

https://en.wikipedia.org/wiki/Murinae#/media/File:House_mouse.jpg

The researchers then induced strokes in all of the mice, and the brain damage was 60% less devastating in the mice vulnerable to antibiotics than the other group. In order to ensure that the difference in stroke severity was solely as a result of the gut bacteria, the researchers took the feces of the mice with reduced stroke severity, and transplanted it into new mice. Those new mice also exhibited a resistance to brain damage, confirming the belief that the gut bacteria was responsible for the change.

These new findings in the research of mice may be able to benefit humans in the future. Antibiotics or a specific diet may be able to reduce the effect of stroke on the brain. However, the gut microbiome of a mouse is vastly different than the gut microbiome of a human, so it may be a while before new treatments are discovered.

Gut Microbes and Parkinson’s Disease: A Fascinating New Study

Parkinson’s, a disease of the central nervous system, affects approximately one million people in the United States. While the disease known for impairing motor skills, it can also have digestive symptoms such as constipation years before diagnosis. Because of this phenomenon, scientists have begun to investigate the role of gut microbiome composition in this awful disease. One such study conducted by a team at Caltech used transgenic mice to get to the answer. All of the mice overexpressed the protein human a-synuclein, which can form the insoluble fibrils that lead to Parkinson’s. However, the researchers raised some of the mice germ-free, or gave them antibiotics, so no intestinal microbes formed. In these mice, Parkinson’s-like symptoms and brain pathology decreased. In addition, the researchers found that the mice that did have gut microbiota had brain inflammation that the germ-free mice didn’t. Only when the researchers fed the germ-free mice short-chain fatty acids (to stimulate gut microbiota) did they show signs of inflammation and other Parkinson’s symptoms. This suggests that gut microbiota that produce short-chain fatty acids could be what triggers this disease.

The researchers then tried to investigate more about which gut bacteria could cause Parkinson’s. Since different communities of gut bacteria live in people with Parkinson’s disease than in healthy people, they wanted to find out if these different communities are merely a byproduct or a cause of the disease. To do so, they transplanted human gut-derived microbes from Parkinson’s patients into some mice, and microbes from healthy people into others. The transgenic mice with microbiota from the Parkinson’s patients ended up with typical Parkinson’s symptoms like motor dysfunction. However, wild-type mice (mice that didn’t overexpress human a-synuclein) weren’t affected. This finding shows that people who are genetically predisposed to Parkinson’s can be afflicted with symptoms if introduced to microbes that are associated with the disease.

This is such groundbreaking work because it establishes a causality between the gut microbiome and Parkinson’s. It also raises questions about the negative affects of short-chain fatty acids on the mice in this study, since they’ve been known to be beneficial in humans. The researchers wish to continue their work by investigating the types of microbes in people with Parkinson’s to get to the fundamental cause of the disease and possible cures.

Do you think that short-chain fatty acids are actually harming humans in unseen ways? Is investigating human gut microbiomes is the right path to find the cure to Parkinson’s? Let me know in the comments!

Three-dimensional Human Intestinal Cells

Human Intestinal Cells Cultured with Gut Bacteria

Credit: Scitechnol Publisher, URL: https://flic.kr/p/fzFoNE

 

Original Article: http://www.the-scientist.com/?articles.view/articleNo/47640/title/Gut-Microbes-Linked-to-Neurodegenerative-Disease/

My Gut is Telling Me To Exercise

Researchers at the University of Colorado Boulder have recently discovered that early life exercise can improve the activity of the gut microbiome. The gut microbiome is the next big thing in scientific research as scientists discover its affect on both general health and disease progression.

“Our gut microbiota contains tens of trillions of microorganisms, including at least 1000 different species of known bacteria with more than 3 million genes”. Microbiota, found in the intestine, help with a range of bodily functions such as digesting foods that the stomach is unable to, producing vitamins, and helping the immune system.

https://en.wikipedia.org/wiki/Escherichia_coli#/media/File:EscherichiaColi_NIAID.jpg

https://en.wikipedia.org/wiki/Escherichia_coli#/media/File:EscherichiaColi_NIAID.jpg

‘Exercise affects many aspects of health, both metabolic and mental, and people are only now starting to look at the plasticity of these gut microbes,”. Bacteria reside in infants’ intestinal tracts after birth to assist digestion and immune development. Exercise increases the effectiveness of these bacteria, and a  healthy gut biome promotes better brain function and causes antidepressant effects.

Scientists studied exercise and its effects on the gut microbiome using juvenile rats and proved this theory. The rats that exercised during their early lives developed a better microbial structure. The adult rats that exercised could not catch up to the rats that exercised as juveniles.

Do you think that this is an obvious or an unexpected idea, that early life exercise strengthens the gut microbiome? Does metabolic health usually coincide with mental health? Why would the gut microbiome be related to gene-making?

Other Sources

http://www.ncbi.nlm.nih.gov/pubmed/26647967

http://www.medicalnewstoday.com/articles/290747.php 

http://www.scientificamerican.com/article/the-guts-microbiome-changes-diet/

 

 

Love and happiness really do come from the bottom of your… gut?

Serotonin is the famous neurotransmitter oft attributed to causing joyous type emotions.  Unlike most neurotransmitters, which are produced predominately in the brain and nervous system, a recent study mentioned in a review article estimate that, “90 percent of the body’s serotonin is made in the digestive tract. […] [C]ertain bacteria in the gut are important for the production of peripheral serotonin.”

uBiome - Microbiome Sequencing Gut Bacteria Sample Kit

 

Interesting play on words of the “Microbiome.” The gut microbiome comprises most of our body but very little of our mass… It outnumbers our cells 10 to 1! [Source]

 

Researchers at the California Institute of Technology (Caltech) sought to identify a link between the gut microbiome and the production of the serotonin neurotransmitter. Peripherally made serotonin is already understood as a product of the digestive tract, however, is there a link between the myriad of bacteria that compose our gut microbiomes and the neurotransmitter? What they found, was surprising; notwithstanding the known communicative link between the nervous system and the microbiome, the researchers found that the microbiome is not directly responsible for most of the production of the neurotransmitter.  The bacteria interact and stimulate the production of serotonin by the intestinal cells.

 

To arrive at this conclusion, the researchers studied the effects of “germ-free” mice.  They found that the mice that exhibited a dearth of flora within. Experimental results indicated that the mice produced around 60% less serotonin than mice with normal gut microbiomes.  The experiments also demonstrated an interesting result that may lead to future studies on the serotonin deficiency treatments–the researchers found that when augmenting the gut microbiomes with bacteria responsible with serotonin production stimulation, the levels of the neurotransmitter increased. Of course, the subject is vastly complicated, and will therefore require extensive research to more fully understand.

Original Article

Study from Article

Serotonin Wikipedia Page

Image Source

Infants’ Feces Says a Lot about the Gut Microbiome

Who knew studying babies’ poop can actually lead to amazing discoveries about childbirth, breastfeeding, antibiotics, allergies, and asthma?

That’s exactly what scientists Fredrik Bäckhed and Jovanna Dahlgren at the University of Gothenburg, Sweden, and Wang Jun at the Beijing Genomics Institute-Shenzhen, China recently learned when they conducted a study analyzing feces from 98 Swedish infants.

But before we get into the details of the study, let’s get down the basics first. What exactly is the gut microbiome?

Gut microbiome is the name given to the population of microbiota organisms that live in the human intestine. These microorganisms are unique, not only because there are trillions of them but also because they have milliions of genes, and can function as a person’s identity card (much like a fingerprint or a strand of hair).

Screen Shot 2016-01-08 at 10.45.15 PM

(Source: https://en.wikipedia.org/wiki/Fecal_bacteriotherapy#/media/File:E_coli_at_10000x,_original.jpg)

Recently there’s been a lot of buzz in the science world about the gut microbiome because it seems as though it plays various crucial functions, and this study is just one of many. The Swedish and Chinese scientists discovered a few ways in how the gut microbiome affects childbirth, breastfeeding, and development.

There are two ways to give birth: vaginally or via a cesarean section, or C-section. Comparing the feces collected from babies born vaginally and from babies born via C-section, scientists discovered that the feces from the latter contains a significantly less similar microbiome to the microbiome of their mothers.

They also determined that nutrition during the early stages of an infant’s life is a core factor in the development of the gut microbiome.

Our findings surprisingly demonstrated that cessation of breastfeeding, rather than introduction of solid foods, is the major driver in the development of an adult-like microbiota

-Fredrik Bäckhed, lead study author

Bacteria rely on the mother’s milk to grow. Once the bacteria’s access to that milk stops, the bacteria stops growing. In its place, adult-like microorganisms emerge.

In addition, the gut microbiome acts as nutrients and vitamins to the infant’s growth and development, and gives aid to important processes such as making amino acids.

The study also critiques the amount of antibiotics given to babies when they’re born. There’s speculation that the baby’s gut microbiome is negatively impacted by the overabundance and overexposure of antibiotics. Besides the obvious risk of antibiotic resistance, one hypothesis is that when exposed to antibiotics early on, the gut microbiome loses important bacteria that helps immune cells mature. This is believed to be the reason why allergies and asthma are now widely prevalent.

Though this study is just a preliminary, it’s amazing just how big of an effect the gut microbiome has on us, and how much new research is coming out.

Want to learn more about the gut microbiome? Check out other sources about the microbiome, such as it’s relationship on the brain, and how it can change the brain’s function, how it can help reduce weight, and junk food’s negative impact on it, and make sure to comment below!

 

 

Original Article

Dysbiosis: Does Imbalance Help?

The gut microbiome is a very large collection of mutualistic relationships between microorganisms and an animal. In our case, these microorganisms control very much of the digestive tract and have influences throughout the body. Crohn’s disease is something that can happen due to imbalance in this microbiome or “dysbiosis“. Usually marked by inflammation in the digestive tract, this disease is a result of an autoimmune response against possibly microbial antigens. Although there is no cure, scientists have determined the best course of action is to relieve the symptoms. This results in disruptions to the gut microbiome.

Inflammation of the colon due to Crohn’s disease

Scientists studying responses in the gut microbiome have found that treatment for Crohn’s disease have caused various responses in the people in the experiment. Antibiotics have been found to decrease bacterial growth in the tract while allowing fungus to grow more freely. Formula diets relieved inflammation and other symptoms but didn’t repair bacterial balance in the microbiome. Immunosuppressants decreased inflammation and bacterial dysbiosis at the expense of increasing fungal dysbiosis. All these methods don’t seem to work out.

But what if the microbiome does not need to be restored to remain healthy? Formula diets caused more dysbiosis but were able to alleviate symptoms. Suddenly, the microbiome does not seem to be as necessary as previous studies suggest. However, this experiment only measures a few variables. Results beneficial to treatments for Crohn’s disease may cause something bad to happen elsewhere in the microbiome. Replacing the gut microbiome would definitely have massive side effects.

Perhaps one day, we could find some way to substitute parts of our mutualistic relationship with the bacteria inhabiting our gut. However, that day seems far off. For now, we should probably stick with what we have.

Original Article

Stress and your Gut Microbiota

Stress. It’s something all people deal with- whether in large or small amounts- we all know what it feels like. Stress doesn’t always mean staying up to pull an all-nighter and barely making the deadline for a paper, it can be just the anxiousness of flying and getting all your things packed before a trip. In general, stress messes with our immune systems in a lot of different ways. There’s a lot of research on the different ways that stress can affect our bodies ranging from our brains to our hearts. New research has shown another way that stress affects our immune systems: through our gut microbiota. What is our gut microbiota? Formally called gut flora, our gut microbiota is the microbe population living in our intestine. Research has revealed that this microbe population is extremely sensitive to any change in our lifestyles, stress included.

The number one thing that affects our gut flora is our diet. Our bodies are very sensitive to what we eat and how active we are. Problems in giving our bodies proper nutrition and exercise can result in mental health problems, diabetes, obesity, or cancer. Stress, however, has been shown to have a very big impact on our gut. An article reported in Medical Daily described a study done on wild squirrels. The researchers examined squirrel microbiomes and their stress hormone levels. They found that the more stressed a squirrel was, the less variety of bacteria in their gut. They concluded that a healthier squirrel would have more diverse gut bacteria. They assume the same is true for humans, but will have to test to verify. On a side note, they also conducted a test where they found that pregnant women under stress were found to transfer negative effects of stress to their children through vaginal microbiota.

220px-Eastern_Grey_Squirrel

Here is a possibly stressed squirrel  (although he seems happy eating the nuts).

Yet another study was conducted and published through The Atlantic on gut microbiota- specifically on “traveler’s constipation.” You might be wondering why I’m mentioning this because, let’s face it- who wouldn’t want to be traveling on a flight to the Bahamas right about now? For our gut, however, this can pose a lot of stresses we wouldn’t think about. About 40% of people say they suffer from travelers constipation, so let’s find out what this is all about. Firstly, on vacation our eating habits change. Whether this means coming home for the holidays and binge eating cookies, or eating a lot less than you normally eat, your gut is sensitive to both. Another, more surprising effect is the change of scenery- your gut is extremely sensitive to change of setting. Anytime you leave your general habitat, in fact, it throws your gut flora off balance- especially if the time zone changes because it messes up routine. For some, the mere thought of traveling can cause difficulty with their bowel movements. Sitting on planes or in a car for long periods of time can also really mess with your gut because part of what helps us “go” is moving around. This is why exercise can actually help you to go to the bathroom. All of these things are things we might not really think about because we don’t understand why it happens or we might not even realize it’s happening sometimes.

Our gut is often called the “second brain”, because millions of neurons line the intestines so it really does play a role in your mental state. Diet and exercise are extremely important in maintaining a healthy gut. Doctors and researchers have have recommended sleep, a lot of water, yogurt, probiotics or other fermented foods, foods high in fiber and meditation and mindfulness. These two might be surprising, but it makes sense. If our gut really is our “second brain” we should take really good care of our mental health through meditation, being mindful, and even therapy.

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