BioQuakes

AP Biology class blog for discussing current research in Biology

Tag: microbiota

Your Gut Microbiota Could be Influencing Mental Health Disorders: Could Psychiatric Medications Change This?

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On November 17, 2019

In Student Post

Mental Health and Gut Bacteria 

Newly published research in rodents and continuing research in humans explores the effects of psychiatric drugs, including antidepressants, on the composition of gut bacteria. They have examined how the effects on gut microbiota, typically caused by naturally occurring metabolic changes in the gut, may influence connection with the nervous system rendering some negative effects on mental health. The most common mental health conditions connected to changing composition of the gut microbiome are anxiety and depression. 

This comes from a recent study that Medical News Today has released, reporting on different bacteria that play a part in synthesizing neuroactive compounds in the gut. These neuroactive substances interact with the nervous system, influencing the likelihood of developing depression or anxiety. This research has been proved more extensively and directly in rodents, but the research in humans provides similar conclusions, allowing scientists to partially conclude the effects in humans–research on this topic in humans is likely to expand greatly in the near future. 

How can gut microbiota be affected by different psychotropics? 

The Study and Results:  

Provided this link between changing gut bacteria and mental health, researchers from University College Cork, in Ireland, set out to investigate this in rodents. First, the team “investigated the antimicrobial activity of psychotropics against two bacterial strain residents in the human gut, Lactobacillus rhamnosus and Escherichia coli.“The psychotropics that the researchers conducted this study with included fluoxetine, escitalopram, venlafaxine, lithium, valproate, and aripiprazole.

Then, the scientists studied “the impact of chronic treatment with these drugs” on the rats’ microbiota. The scientists gave the rodents psychiatric drugs for a period of 4 weeks, ending the study by inspecting the effects of the drugs on the rodents gut bacteria. They found that lithium and valproate, mood stabilizers that can treat conditions including bipolar disorder, raised the numbers of certain types of bacteria. These included Clostridium, Peptoclostridium. On the other hand, selective serotonin reuptake inhibitors (SSRIs), fluoxetine and escitalopram (both antidepressants), ceased the growth of bacterial strains such as Escherichia coli.

“We found that certain drugs, including the mood stabilizer lithium and the antidepressant fluoxetine, influenced the composition and richness of the gut microbiota,” says head researcher Sofia Cussotto. 

Conclusions from the Study, and what the Future Holds 

Dr. Serguei Fetissov, a professor of physiology at Rouen University, in France commented on the study, saying: “At the moment, it would be premature to ascribe a direct role of gut bacteria in the action of antidepressant drugs until this work can be reproduced in humans, which is what the authors now hope to do.”

However, the implications and further goals and hopes of this research is to directly prove that “psychotropic drugs might work on intestinal microbes as part of their mechanisms of action,” says Cussotto

Do you think it is too early to assume a direct connection between gut bacteria and mental health in humans? Comment about this below.

Further Research

https://www.medicalnewstoday.com/articles/amp/326299 

https://www.medicalnewstoday.com/articles/319117.php#1 

 

 

 

The Effect of Malnutrition on the Gut Microbiome

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On November 15, 2019

In Student Post

Malnutrition is a brutal issue that has plagued the world for years and affects communities that can’t afford to help themselves. Recently there has been a link between malnutrition and the condition of the gut microbiome. The gut microbiome describes the microbiota, micro organisms, that live in the digestive tract and have  David Relman, a microbiologist at Stanford University School of Medicine, explained the two studies that believe that tailoring a specific diet for people suffering from malnutrition can improve their gut microbiomes and subsequently improve their health.  Tahmeed Ahmed, director of nutrition research at the International Centre for Diarrhoeal Disease Research, and Jeffrey Gordon, a gastroenterologist and microbiome researcher at Washington University, started two studies into how malnutrition effects the microbiome. After observing healthy and malnutrition babies grow into toddlers, the two noticed how malnutrition causes the micro biome to remain immature and stay in the same state as a babies instead of maturing like a normal person’s. The two then conducted studies on mice looking for changes in mice with malnutrition and found that the mice had weaker bones, less muscle mass, and impaired metabolism. From these results the two scientists have deduced certain foods that should be given to help fix immature mircobiomes. Current food in care packages do not have these necessary requirements to fix microbiomes. They contain food like rice and powedered milk, but chickpea, soy, peanut flours, and bananas have been proven to help the microbiome and should be added into care packages. By targeting the microbiome in malnutrition, these scientists have been able to reverse the negative affects and force the body to catch up on lost growth. The leading obstacle with this discovery is that malnutrition effects the poor, who do not have access to the healthier kinds of food required to repair their crippled microbiomes.

Health and Disease in a New Light

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On November 13, 2019

In Student Post

Microbiota are groups of organisms that live on and in some mammals. Animals, such as humans, who live in a state of mutualism with these organisms have them mostly on parts of their body with large surface areas. This includes skin and the intestinal tract. The human gut microbiome is a complex community of organisms that have been studied over the past decades and most intensely within the past fifteen years. So far the information on the human gut microbiome is limited and the research on it is somewhat inconclusive, raising more questions than it answers questions; however, that is a side effect of most research that is just beginning to be analyzed more in depth. The idea that we are just now starting to study and understand these organisms that have lived on and in us for centuries is a topic that is cutting edge and very interesting.

Microbiota

A short coverage of information about microbiota in the intestinal tract includes the following. In mammalian animals, these organisms play an important role in the formation of intestinal mucosa as well as a healthy systematic immune system. Animals that lack microbial cells contain abnormal numbers of several immune cell types and immune cell products, as well as have deficits in local and systemic lymphoid structures. Therefore, their spleens and lymph nodes in them are poorly formed and their intestinal mucosa, deficient. Mice with a lack of microbiota were known to have a lower amount of plasma producing cells – which make antibodies of a certain type. This is due to the fact that the microbiota is regulated by the plasma cells in mammals and it is found unnecessary to have a large amount of them in animals lacking the organisms. These mice also exhibited an impaired ability to regulate cytokine levels – any of a number of substances, such as interferon, interleukin, and growth factors, which are secreted by certain cells of the immune system.

In 2010 there was a study done that was comprised of making cultures of these organisms and bacteria in the human intestinal tract outside of the human body because we do not have the necessary technology to study the microbiota in their hosts. This study yielded the publication of a paper titled “Gut Microbiota in Health and Disease” which gives a detailed overview of the findings of this study. Briefly, a colonization of mice lacking microbiota with altered Schaedler flora (ASF) was insufficient to promote differentiation of Th17 cells (which play an important role in defense against infection), despite the fact that ASF includes a number of bacteria from the Bacteroidetes phylum (microbiota). Researchers concluded the there is no way to be sure of the affects of microbiota. Meaning although there was no lack of microbiota, the mice still had an immune system deficiency in the same way that mice lacking any microbiota did. Since the health and abundance of microbiota in the gut microbiome is so closely related with the ability of the immune system of the host, it is concluded that changes in the microbiome can lead to onset of diseases/illnesses in the host. These factors can also change with environmental changes such a dietary choices of the host. Understanding the dynamics of the gut microbiome under different conditions will help us diagnose and treat many diseases that are now known to be associated with microbial communities.

Analyzing the affects of microbiota in the human gut can reveal topics about human pathology that we did not know before. Therefore, scientists look forward to the development of studies on this topic.

Babies Born via C-Sections Have Different Gut Microbiota

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On November 12, 2019

In Student Post

A study reported to the Journal Nature, found evidence that infants born by C-sections have different microbiota than babies born vaginally. The study found that method of delivery plays a factor in which bacteroids colonizes the intestines of infants immediately after birth. 

The study was conducted in the United Kingdom. Researchers took stool samples from 596 babies in total– 282 born via cesarean section and 314 born vaginally. Scientist took samples four, seven and 21 days after birth and samples a couple of months later after birth. They also took stool samples from 175 mothers took help determine the origin of the gut microbiota. 

Research found that babies born through cesarean section have less “good” bacteria from their mothers and more bacteria from the environment in which they are born. The infants born by c-sections contained pathogens such as enterococcus, enterobacter and klebsiella, which have been found in hospitals. Via natural birth, infants’ intestines contained gut microbiota from their mother as well as the environment in which they were born. Later on in infancy, researchers found that babies born by c-sections showed more similar gut microorganisms as their naturally-birthed counterparts. 

Scientists found that in the gut microbiota found in infants born via c-section, some pathogens contained antimicrobial resistance and bacterial virulence factors. This could potentially make infants born by cesarean sections more susceptible to infections and weaken their immune systems. 

Researchers concluded that the environment in which babies are born factor into how gut microbiota will be composed from birth to infancy. But it still remains unclear if the initial difference in gut microbiota will have any health effects later on in life. 

Regardless of this study, c-sections are still important to the health of millions of babies and mothers worldwide. In no way should this study discourage women from having c-sections; especially, if they are a necessity. Caesarean sections have saved millions of lives and will continue to do so.

Gut bacterial and fungal community interactions identified for first time as a factor in Crohn’s disease

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On January 16, 2017

In Student Post

Recent studies have found that the interactions between the gut bacteriome and mycobiome are closely related to the development and severity of Crohn’s Disease. Crohn’s disease is an inflammatory bowel disease, that causes inflammation of the lining of your digestive tract. It can lead to abdominal pain, severe diarrhea, fatigue, weight loss and malnutrition.

In the past, the majority of studies have focused on the bacterial microbiota (bacteriome), and little attention has been paid to the fungal lining of the stomach (mycobiome). In a recent study, led by Professor Mahmoud A. Ghannoum from teh Center for Medical Mycology at the Case Western Reserve University in Cleveland, Ohio, has found new bacteria and fungi interactions that may play major roles in the development of Chron’s Disease. In his study, Prof. Ghannoum found an increase in possible pathogenic bacteria and a decrease in beneficial bacteria in CD patients.

Three organisms often found included the S. marcescens, C. tropicalis, and E. coli. The three organisms work together to create a bio film on the inner linings of the stomach. As we’ve learned in class, bacteria are unicellular organisms. They have no nuclear membrane, making them Prokaryotic. The three organisms C. tropicalis, S. marescens and E. coli were highly correlated in individuals with CD and may be key determinants of CD development.

I found this study fascinating because it brings us one step closer to discovering the possible causes of Crohn’s Disease. Approximately 1.6 million Americans suffer from Crohn’s Disease. Finding a cause, would be a huge gain in trying to find a cure. Having a loved one who suffers this disease, it gives my family and I hope for a healthy and pain free future. The questions I’d have, is why do those three specific types of bacteria increase in Crohn’s patients? Or how do they get there in such large numbers?

 

Main link: http://www.gutmicrobiotaforhealth.com/en/gut-bacterial-fungal-community-interactions-identified-first-time-factor-crohns-disease/

 

Secondary sources: http://cid.oxfordjournals.org/content/44/2/256.full

https://www.ncbi.nlm.nih.gov/pubmed/19817674

Why Microbiota Will Ruin Your New Years Resolution:

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On January 11, 2017

In Student Post

This year, people across America will make New Years Resolutions about eating better, losing weight, and being healthier. Unfortunately, microbiota, those pesky little gut bacteria in charge of digestion, will be trying to foil your plans.

Microbiota is the term used to describe the entire population of trillions of microbes living in our intestines. Every person has a unique set of individual microbiota, based both on genetics and environmental factors such as diet. It is crucial in the digestive and immune systems, and in producing some vitamins.

A new study has shown that humans living an unrestricted American diet develop certain gut microbiota, that aren’t so easy to get rid of, and once a person switches to a nutritious, plant based diet, that microbiota interferes, counteracting the effects of the diet. In an experiment at the Center for Genome Sciences and Systems Biology at Washington University in St. Louis, scientists took the microbiota of human samples, half who followed calorie restricted plant-rich diets, and half who had un-restricted diets, and implanted them into test mice. They then switched all the mice to a healthy, plant-rich diet. Although both groups responded to the diet, those with the unrestricted diet had a much weaker and delayed reaction. Scientists then started co-housing the groups of mice. The healthy diet microbiota slowly migrated to the unhealthy mice, accelerating their reaction to the diet, symbolizing hope for future strategies for improving the effectiveness of diets using this data.

Photo:

https://commons.wikimedia.org/wiki/Mus#/media/File:House_mouse.jpg

As a US government publication, this picture is in the public domain

Are Antibiotics Killing More Than Just Infections?

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On September 24, 2014

In Student Post

What are in your antibiotics?

We all take antibiotics. Staph infections, Strep throat, etc. and they get the job done. Within two or three days, sometimes a week, you’re cured and infection-free. But is that really best for us?

Microbiomes are what make us so unique and individual. In fact, we have more bacteria cells that human cells in a 10 to 1 ratio. We have different microbiomes for different parts of the body; our mouth has a different microbiome than our skin microbiome which has a different microbiome than our gut microbiome. We can influence our microbiomes by what we eat, or rather they influence us based on what we eat. As part of an evolutionary benefit, our microbiomes adapt to newly introduced food within days, which we previously thought took years to change. In other words, if you didn’t eat carrots for three years and sporadically ate carrots one day, your microbiome would activate bacteria that was previously dormant to digest the carrots within days. Think for a moment: a bacteria your body hadn’t made in three years is suddenly recolonized and active in helping you digest within a few days. It’s truly amazing! However, the rest depends on how you were born.

If you were vaginally born, your first encounter with bacteria (bacteria from the placenta is still controversial as to whether babies acquire some of their intestinal bacteria before birth) was in the birth canal, which is exactly where you get your microbiota colonies from. If you were Cesarean born, you might find that you have a higher chance of chronic conditions like asthma or Celiac’s disease simply because you received your mother’s skin microbiome instead of her vaginal microbiome. If you were not breast fed, you are more likely to contract similar conditions because breast milk contains nutrients that cannot be broken down by your digestive track. Rather, they surpass your digestive track and nourish microbiota. Formulas were unaware of this and therefore did not contain everything necessary for your microbiota health, but formulas have been making adaptions to fully mimic these qualities of breast milk.

Say you did all of the right things: you eat whole, unprocessed foods that can nourish your microbiome, you were vaginally born and you were breastfed. It’s completely possible that you have a wonderful, flourishing microbiome. However, you likely do not.  Processed foods do not contain enough prebiotic nutrients (food for microbes). Although one associates Western civilization with nutrition and health, we are actually considered “impoverished” in the world of microbiomes.

The big problem with the Western diet is that it doesn’t feed the gut, only the upper G I. All the food has been processed to be readily absorbed, leaving nothing for the lower G I. But it turns out that one of the keys to health is fermentation in the large intestine. Stephen O’Keefe

Those with no contact to the Western world and its medicine, pesticides, sterility and processed foods have a rich and diverse microbiome. Not to mention the growth hormone in cows, which changes the microbiota for a hastened growth as well as the metabolism of the liver. They even stimulate an increase in body fat. Western medicine, however, affects us in less visible manner. Our antibiotics are too strong for our own good; they destroy the pathogenic bacteria, yes, but they also destroy the health-promoting ones. Therefore, some argue that we should improve our diagnostics to prescribe fewer and narrow-spectrum antibiotics to kill the harmful bacteria while reducing the collateral damage. (Dr. Blaser) These heavy duty antibiotics not only destroy the healthy, diverse microbiota, but have a permanent effect if used for a second course; the microbiome will bounce back but it will not be able to return to its original state. In addition to this, antibiotics have been trying to eliminate H. pylori since 1983 when they found it could lead to stomach cancer or peptic ulcers, when in fact its disappearance could be contributing to acid reflux and obesity. Due to our continual efforts to eliminate H. pylori from the microbiome, it is unlikely that we will see it in upcoming microbiomes due to antibiotics, and “each generation is [already] passing on fewer of this microbes.” Prevotella, for example, is a gut bacteria extremely difficult to find in Western society but relatively common in underdeveloped countries. One woman had unusually high levels of this bacteria in her microbiome, but after one course of antibiotics for oral surgery, her wonderful microbiome was reduced to the average American bacterial standards. 

One of the more striking results from the sequencing of my microbiome was the impact of a single course of antibiotics on my gut community. My dentist had put me on a course of Amoxicillin as a precaution before oral surgery. (Without prophylactic antibiotics, of course, surgery would be considerably more dangerous.) Within a week, my impressively non-Western “alpha diversity” — a measure of the microbial diversity in my gut — had plummeted and come to look very much like the American average. My (possibly) healthy levels of prevotella had also disappeared, to be replaced by a spike in bacteroides (much more common in the West) and an alarming bloom of proteobacteria, a phylum that includes a great many weedy and pathogenic characters, including E. coli and salmonella. What had appeared to be a pretty healthy, diversified gut was now raising expressions of concern among the microbiologists who looked at my data.

Her bacterial composition will return to something that somewhat resembles her original microbiome, but every course after that will decrease potential microbial recovery and also decrease invasion resistance (keeps pathogens from gaining a toehold by occupying potential niches or otherwise rendering the environment inhospitable to foreigners e.g. H. pylori regulates stomach acid to make the environment unfavorable to other bacteria that wants to colonize; vaginal pH is kept low so the environment is too acidic for foreign bacteria to colonize, etc.) So the next time you take an antibiotic, ask yourself: what am I doing to my microbiome?

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