The influence of the microbiome on brain development

bidirectional link of between gut and brain. Brain influences motility, secretion, nutrient delivery and microbial balance in the gut. Gut influences neurotransmitters, stress/anxiety, mood and behaviour for the brain.
Figure 1. (from PsychSceneHub, sourced from FodMapEveryday). The brain and gut have bidirectional influence on each other.

Background

We live with an astonishing number of microbes in our bodies. Recently, scientists have been finding increasing evidence that one’s microbial profile (the set of different types of bacteria within their bodies) is shaped at birth, often ‘inherited’ from a mother when babies pass through the birth canal. One’s microbial profile, along with the conditions within one’s body that create an environment that supports the growth of some bacteria and prevents the growth of others, is called microbiota. Its development and stabilisation co-occurs with the development of a child’s nervous system; abnormal microbiota development is suggested to cause disruption in later cognition and behaviour (Diaz et. al, 2016) Continue reading “The influence of the microbiome on brain development”

Nasty Salmonella Infections Could be Defeated by Viruses Inside Our Guts Without Antibiotics

    Salmonella up closeSalmonella up close (Food Safety News)

BACKGROUND

Salmonella are bacteria that are often responsible for food-borne illnesses. The symptoms of Salmonella infection is “nausea, vomiting, abdominal cramps, diarrhea, fever, chills, headache, and blood in stool” (Mayo Clinic, 2019). Sometimes Salmonella infections need to be treated with antibiotics, but it is becoming more common that Salmonella and other infectious bacteria are antibiotic resistant due to overexposure to antibiotics (Centers for Disease Control and Prevention, 2019). When someone with an antibiotic resistant bacteria gets sick, it can be incredibly difficult to treat if the person’s immune system isn’t able to fight off the illness on its own. However, there’s an alternative, bacteriophages are viruses that infect and kill specific bacteria or archaea. This treatment option has gained interest in the last decade due to the increasing abundance of antibiotic resistant bacteria.  Continue reading “Nasty Salmonella Infections Could be Defeated by Viruses Inside Our Guts Without Antibiotics”

Gut Instinct: Brains on Bacteria

Man meditating holding phone with digestive system and brain shown as connected.
(Image:  https://atlasbiomed.com)

Background

You are what you eat, or so many people have been told. Researchers today are discovering that this age-old saying may be even more true that previously thought. “The Human Microbiome Project (HMP) was a United States National Institutes of Health (NIH) research initiative to improve understanding of the microbial flora involved in human health and disease”(7). Actually, the human microbiome project is a continuing effort of scientists from across the globe working together to better understand how all of the microbiological members of the immediate human environment (the microbiome) interact with our daily lives. The human microbiome is vast network of trillions of microorganisms that live in and on the human body including bacteria, fungi, parasites, and viruses(9). According to the National Institute of Health’s website, the human body is made up of 1-3% of microorganisms by mass(1).    Continue reading “Gut Instinct: Brains on Bacteria”

Comparing the Dandruff vs. Healthy Scalp Microbiome

Background:

Around half of the adult population worldwide is affected by the condition known as dandruff (Soares et al. 2016). Dandruff is characterized by small white flakes that are shed from the scalp, which often end up in a person’s hair or on their shoulders. Dandruff can cause intense itchiness of the scalp. Having visible dandruff flakes can lead to social embarrassment, due to the stigma that dandruff is caused by poor personal hygiene (e.g., not washing your hair enough). This is not true, however. It is not known what the exact cause of dandruff is, but Malassezia yeasts, specifically an imbalance/overabundance of them, are/have been suspected to play a role in its development (Wang et al. 2015). Malassezia is a fungal genus, and it is normal for fungi belonging to it to live on human skin (Soares et al. 2016), along with other species of fungi and bacteria, like Propionibacterium acnes and Staphylococcus epidermidis (Clavaud et al. 2013). In 2018, researchers in India conducted a study on the scalps of 140 Indian women to learn more about what kinds of microbes (including bacteria and fungi) were present on dandruff scalps vs. healthy scalps (Saxena et al. 2018). Continue reading “Comparing the Dandruff vs. Healthy Scalp Microbiome”

Bacteria and fat ratios: can being male or female determine your bacteria?

Background:

Much insight has been gathered about gut microbiota (the bacteria present in our bodies) and its overall role in human health, but a majority still remains unknown. Based on previous studies it is understood that gut microbiota and diversity are greatly influenced by individuals and their weight characteristics (lean and obese) (Min et al., 2019).  But little to nothing is known in regards to sex-specific association, fat distribution and their effects on the bacterial gut communities. While men tend to have a lower average body fat percentage than females, the locations in which men and women store their fat could also play a great role in overall gut microbiota (Min et al., 2019) . These variations in the microbiome could possibly be linked or help explain adverse health effects seen in men and women, such as abdominal obesity in men and metabolism differences (Min et al., 2019). It is believed that the distribution of body fat on women aids in the protection in metabolic diseases such as type two diabetes and other life threatening illnesses (Karastergiou et al., 2012). Continue reading “Bacteria and fat ratios: can being male or female determine your bacteria?”

The Scoop on Poop: Possible Links Between Gut Microbes and Autism Spectrum Disorder

Background:

Autism spectrum disorder (ASD) is a developmental disorder that affects communication and behavior (NIMH, 2019).  The CDC reports that about 1 in every 59 kids is identified with ASD (CDC, 2019).  It is very common for children with ASD to have some degree of gastrointestinal (GI) issues, such as constipation, diarrhea, and abdominal pain (Hsiao, 2014).  It is estimated that between 30-50% of children with ASD also have GI problems (Buie et al., 2010, McElhanon et al., 2014), but it is unknown why this is and what is causing it.  Scientists have looked into an imbalance of the gut microbiome (all the living organisms, such as bacteria, within the gut) as a potential factor in causing ASD symptoms and have found differences between the gut microbes of ASD children and neurotypical, or ‘normal’, children (children with no mental disabilities) (Finegold et al., 2002, Adams et al., 2011).  The researchers think that reductions in beneficial microbes and increases in harmful microbes could be causing ASD symptoms and associated problems.  However, we lack evidence to determine if the differences in microbes are actually the cause of the ASD symptoms, or if the ASD is causing the differences in microbes. Continue reading “The Scoop on Poop: Possible Links Between Gut Microbes and Autism Spectrum Disorder”

It Takes a Village: Selection Drives the Formation of Dental Caries in Children

Dentist cleans woman's teeth.
Photo credit Max Pixel

Background:

As children we are told to brush our teeth and floss twice a day. An uncomfortable dental experience as a child can create dental anxiety in adulthood. This anxiety can prevent patients from seeking the care they need. The development of caries, or cavities, in the mouth can have lasting impacts if not treated properly in both children and adults. Caries develop on teeth due to the creation of an acidic environment from the bacteria inhabiting the mouth (Marsh 1994). The acidity eats away at the enamel, and eventually the softer pulp, or dentin, within the tooth, leaving an exposed and sensitive area that requires medical attention (Bowen et al. 2017). The prevalence of decay in primary teeth is notably higher in children aged 1 to 4 while young adults aged 15-19 years old have a higher prevalence of decay present in permanent teeth (Kassebaum et al. 2017). Because children develop higher levels of cavities than adults, protecting young permanent teeth is an important area for research. Why are children more likely to develop caries? And what can be done to lessen the spread of this disease? For many years scientists attributed the development of caries to the bacterial species Streptococcus mutans. With the advent of new technology and further information of how microbes interact with each other, scientists are now looking at old problems with modern solutions. Instead of merely describing the presence of microbes, scientists are now beginning to see what is happening between various microbial species in the human microbiome.  Continue reading “It Takes a Village: Selection Drives the Formation of Dental Caries in Children”

Turning Up the Heat: The effects of bacterial and viral co-infection in children

Background:

In young children the gastrointestinal tract (GIT) is a common infection site, with severe infections causing gastroenteritis (irritation and inflammation of the stomach and gut). These infections are most commonly caused by viruses and bacteria, although there are also cases of parasitic causes, such as giardia. Rotavirus and norovirus are most commonly found to be viral sources of infection while varieties of E. coli (EPEC and EAEC in the case of  this study) are frequent bacterial infecting agents. Globally, acute gastroenteritis (AGE), more commonly known as the stomach flu (not to be mistaken for influenza), is responsible for over 1.3 million deaths every year, about 15% of all childhood deaths in children under five (Mathew, S. et al. 2019). This early life (6 months or younger) AGE has also been linked with a significant increase in the development of asthma, allergic rhinitis (hay fever), and atopic dermatitis (eczema) later in childhood. This is exacerbated if the gastroenteritis results in a long term imbalance to the microbiome in the child’s developing GIT, with the effects potentially worsened by the application of antibiotics (Pan, H.H. et al. 2019).  Continue reading “Turning Up the Heat: The effects of bacterial and viral co-infection in children”

Our Celestial Bodies: Tracking the Microbiome of Astronauts in Space

Astronaut Scott Kelly in space
Astronaut Scott Kelly in space from Morris 2019

Jumping into the Black Hole…

Space, it’s the final frontier. Since 1961 when the first humans entered space, we’ve been curious about it’s potential. Will the moon become the next hot tourist destination? Could militarization of space be possible? What about colonization of another planet? However, to address any of these questions, we first need to confidently answer the question “can we even survive space?” Many studies have been done on the impact of spaceflight on the human body, from bone mass and biochemistry to changes in the signaling system within the brain. However, apart from a small portion of the NASA Twins Study (more information on this study here), very little research has been conducted on the effects of spaceflight on the microbiome. In recent years the human microbiome, or collection of all microbiota living within and on our bodies, has been at the forefront of medical research and researchers are now able to link changes in the microbiome with diseases like diabetes, inflammatory bowel disease, and preterm birth (The iHMP Research Network Consortium 2014).  Continue reading “Our Celestial Bodies: Tracking the Microbiome of Astronauts in Space”

How the Environment Affects the Microorganisms of Our Skin

Background

Microorganisms are present all around us, but our interaction does not stop at that. There are millions of these microscopic creatures living in and on our bodies. While this may seem alarming at first, most of these microbes cause no harm, and in many cases play an important role in our health. Studies have shown that our microbiota, which are microscopic organisms that live in our bodies, have a wide range of functions from supporting our immune system (Mazmanian et al., 2008), to helping us stay free of infection (Fredricks et al., 2005). Scientists are trying to distinguish the range of what a healthy human microbial composition is. By establishing this range, the hope is to use the microbiome to detect and treat a variety of diseases (Rosenthal et al., 2011). Continue reading “How the Environment Affects the Microorganisms of Our Skin”