Week 3.1: The role of microbiota in affective disorders

Question 1

The collection of all the microorganisms (bacteria, viruses, fungi, etc.) living in a particular environment, such as the gut.

Often used interchangeably with “microbiota,” though it encompasses a broader context including the microorganisms’ genetic makeup and their interactions with the environment.

Answer 1

Microbiome

Question 2

What is the connection between microbiome and mental health?

Answer 2

Research suggests that the gut microbiome can influence mood and mental health, potentially contributing to conditions like depression and anxiety.

Question 3

What is the human body’s microbial population?

Answer 3

The human body hosts trillions of microorganisms, including bacteria, viruses, and fungi.

Question 4

The community of microorganisms (bacteria, viruses, fungi, etc.) living in a specific environment within the body.

Answer 4

Microbiota

Question 5

The Boy in the Bubble: A Case Study

Answer 5

David’s Condition: He was born with a severe immune deficiency condition inherited from his parents.

Germ-Free Bubble: David was raised in a sterile, microbe-free environment to protect him from infections.

Isolation: This setup meant David could not experience direct human touch or contact, leading to severe emotional and psychological distress.

Transplant: At the age of 12, David received a bone marrow transplant from his sister.

Complications: Although the transplant itself was not rejected, David died a few months later due to a dormant virus in his sister’s blood that went undetected.

Question 6

Why are microbes important in immune system development?

Answer 6

Living in a microbe-free environment prevents the immune system from developing properly making one highly vulnerable to pathogens once exposed to the real world.

Exposure to microbes is essential for building a strong and resilient immune system.

Question 7

The community of microorganisms residing in the gastrointestinal tract.

Answer 7

Gut Microbiota

Question 8

What are the functions of Gut Bacteria?

Answer 8

1) Nutrient Provision
2) Aid Digestion
3) Defense Against Pathogens
4) Intestinal Architecture
5) Neurotransmitter Production
6) Intestinal Barrier Maintenance

Question 9

The gut lining that prevents bacteria and other harmful substances from translocating from the gut to the surrounding environment.

Answer 9

Intestinal Barrier

Question 10

A condition where the intestinal barrier is compromised, allowing bacteria and toxins to pass through, leading to inflammation.

Answer 10

Leaky Gut

Question 11

A disorder affecting the large intestine, causing symptoms like cramping, abdominal pain, bloating, gas, and diarrhea or constipation.

Answer 11

Irritable Bowel Syndrome (IBS)

Question 12

Chronic inflammation of the digestive tract, including conditions like Crohn’s disease and ulcerative colitis.

Answer 12

Irritable Bowel Disease (IBD)

Question 13

A persistent, mild form of inflammation that remains in the body for an extended period, often months or years. Unlike acute inflammation, which is a short-term response to injury or infection, chronic inflammation does not resolve quickly and can cause ongoing damage to tissues and organs

Answer 13

Chronic Low-Grade Inflammation

Question 14

Also known as the microbiota-gut-brain axis, this term refers to the complex, bidirectional communication between the gut and the brain.

Answer 14

Gut-Brain Axis

Question 15

The community of microorganisms (bacteria, viruses, fungi, etc.) living in the digestive tracts of humans and other animals.

Answer 15

Gut Microbiota

Question 16

Research studies that observe and measure outcomes without manipulating variables.

Answer 16

Observational Studies

Question 17

A method used to identify and compare bacteria within a given sample. It targets the 16s ribosomal RNA gene, which is present in all bacteria but has regions that vary between different species, allowing for identification.

Answer 17

16s rRNA Sequencing

Question 18

What do we mean when we talk about the composition of the gut microbiota?

Answer 18

Diversity: How many different types of bacteria are there?

Abundance: How much of each type of bacteria is there?

Question 19

The number of different species present in a given environment. Higher richness means more species.

Answer 19

Richness

Question 20

This refers to how evenly the different species are represented. Higher evenness means that no single species is overly dominant.

Answer 20

Evenness

Question 21

High richness (i.e., many different nationalities) and high evenness (i.e., each nationality well-represented).

Answer 21

True Diversity

Question 22

What is the connection between diversity and symptom severity?

Answer 22

There is a negative correlation between diversity and symptom severity. Lower diversity often means worse symptoms.

Question 23

The hierarchical classification of organisms. In this context, it ranges from phylum (broadest category) to genus (more specific category).

Answer 23

Taxonomic Rank

Question 24

A type of bacteria commonly found in the intestines. It is often included in probiotics and supplements due to its health benefits, such as aiding digestion and boosting the immune system.

Answer 24

Bifidobacterium

Question 25

A beneficial bacterium prevalent in the gut. It has anti-inflammatory properties and is involved in producing short-chain fatty acids like butyrate, which are important for gut health.

Answer 25

Faecalibacterium

Question 26

Fatty acids produced by the fermentation of dietary fibers by gut bacteria (ex. butyrate). SCFAs produced by gut bacteria help reduce inflammation

Answer 26

Short-Chain Fatty Acids (SCFAs)

Question 27

A fatty acid that plays a crucial role in maintaining gut health and reducing inflammation.

Answer 27

Butyrate

Question 28

Bacteria that can promote inflammation in the body. Increased levels of these bacteria are often associated with various health conditions, including depression.

Answer 28

Pro-Inflammatory Bacteria

Question 29

What is altered in the microbial composition of people with depression?

Answer 29

Decreased Diversity: Lower richness of bacterial species. Reduced Levels of Beneficial Bacteria Increased Levels of Pro-Inflammatory Bacteria

Question 30

Contain bifidobacterium. These are marketed for their benefits in improving gut health and boosting the immune system.

Answer 30

Probiotics

Question 31

A type of research that collects and critically analyzes multiple research studies or papers on a specific topic. It aims to provide a comprehensive summary of the available evidence.

Answer 31

Systematic Review

Question 32

Observational studies that compare individuals with a specific condition (cases) to individuals without the condition (controls) to identify factors that may contribute to the condition.

Answer 32

Case-control Studies

Question 33

A statistical technique that combines the results of multiple scientific studies to identify overall trends and draw more robust conclusions.

Answer 33

Meta-Analysis

Question 34

A pattern or characteristic that is common across multiple psychiatric disorders, rather than being specific to one disorder.

Answer 34

Transdiagnostic Pattern

Question 35

Can influence mood and behavior. For example, an imbalance in gut bacteria can affect mental health conditions like depression and anxiety

Answer 35

Gut-Brain Axis

Question 36

What are the main components of the gut-brain axis?

Answer 36

Vagus Nerve Neurotransmitters Gut Microbiome Endocrine System Immune System

Question 37

This is the largest nerve connecting the brain to the gut. It plays a crucial role in transmitting signals between the gut and the brain

Answer 37

Vagus Nerve

Question 38

These are chemical messengers that help regulate various functions, including digestion and emotional well-being. Examples include serotonin, dopamine, and gamma-aminobutyric acid (GABA), many of which are produced in the gut

Answer 38

Neurotransmitters

Question 39

These microbes communicate with the brain via the vagus nerve and through the production of neurotransmitters and other chemicals.

Answer 39

Gut Microbiome

Question 40

This system produces hormones that communicate signals related to hunger, fullness, and stress between the gut and the brain

Answer 40

Endocrine System

Question 41

The gut-associated lymphoid tissue (GALT) is a critical part of the immune system in the gut. It helps in the immune response and also communicates with the brain

Answer 41

Immune System

Question 42

What are the two main strategies in studying gut microbiome?

Answer 42

Adding something OR Removing something

Question 43

What are the main methods in studying gut microbiome?

Answer 43

Germ-free studies

Question 44

These involve using germ-free animal models, which are genetically modified animals raised in sterile conditions without any gut microbiota. To understand the role of gut microbiota by observing the effects of its absence on biological mechanisms and behavior.

Answer 44

Removing something: - Germ-free Studies - Antibiotic Studies - Bacterial Infection Studies Adding something: - Supplement Studies - Faecal Microbiota Transplant (FMT) Studies

Question 45

Administering antibiotics to individuals to wipe out their gut microbiota. While useful for treating infections, it can be harmful to the microbiota.

Answer 45

Antibiotic Studies

Question 46

Inducing a bacterial infection in the gut by removing healthy bacteria. Provide insights into how infections impact the gut-brain axis.

Answer 46

Bacterial Infection Studies

Question 47

Adding supplements like probiotics to the diet. Probiotics can help restore and maintain a healthy gut microbiome.

Answer 47

Supplement Studies

Question 48

Transplanting microbiota from one individual to another. To observe the changes in the recipient's biology and behavior, providing insights into the role of specific microbiota compositions.

Answer 48

Fecal Microbiota Transplant (FMT) Studies

Question 49

Produces the stress hormone cortisol. In affective disorders, this axis is often over-activated, leading to increased cortisol production.

Answer 49

Hypothalamic-Pituitary-Adrenal (HPA) Axis

Question 50

An essential amino acid for serotonin production. Probiotics can increase tryptophan levels.

Answer 50

Tryptophan

Question 51

Refers to something that affects the entire body rather than just a specific part

Answer 51

Systemically

Question 52

Is a steroid hormone produced by the adrenal glands, located on top of the kidneys.

Answer 52

Cortisol

Question 53

It is often referred to as the "stress hormone" because it is released in response to stress and helps regulate various functions, including metabolism, inflammation, blood pressure, and the sleep-wake cycle

Answer 53

Cortisol

Question 54

Are small proteins that act as chemical messengers in the immune system. They help regulate inflammation and immune responses by signaling immune cells to act against infections or other threats.

Answer 54

Cytokines

Question 55

A protein that supports the growth, development, and maintenance of neurons. It is crucial for learning, memory, and overall brain health. Increased BDNF levels support brain health by promoting the growth and maintenance of neurons, enhancing learning and memory.

Answer 55

Brain-Derived Neurotrophic Factor

Question 56

A balanced state where the gut microbiota is diverse and beneficial bacteria are abundant.

Answer 56

Homeostasis in Microbiota

Question 57

Why is it important to maintain gut health?

Answer 57

Keeping a healthy and diverse gut microbiota is crucial for preventing inflammation and supporting mental health. A healthy gut-brain axis can help reduce the risk of psychiatric disorders by maintaining low levels of inflammation and stress hormones.

Question 58

Healthy Gut VS Unhealthy Gut

Answer 58

Healthy State: In a healthy gut, beneficial bacteria maintain balance (homeostasis), the gut lining is strong, and inflammation is low. This supports good mental and physical health. Inflamed State: In an unhealthy gut, harmful bacteria increase, causing the gut lining to leak. This leads to higher inflammation and stress hormone levels, which can negatively impact mental health.

Question 59

Plays a crucial role in shaping the gut microbiota, which in turn can influence mental health.

Answer 59

Diet

Question 60

Live microorganisms that, when consumed in adequate amounts, confer a health benefit on the host.

Answer 60

Probiotics

Question 61

What are the components of a healthy and more varied diet?

Answer 61

1) Fruits and vegetables 2) Grains 3) Reduced Sugar, Salt, and Saturated Fats 4) Omega-3 Fatty Acids

Question 62

Provide essential vitamins, minerals, and antioxidants.

Answer 62

Fruits and Vegetables

Question 63

Whole grains like oats, quinoa, and brown rice.

Answer 63

Grains

Question 64

Limiting these can help prevent negative health outcomes.

Answer 64

Sugar, Salt, and Saturated Fats

Question 65

Found in fish, flaxseeds, and walnuts, these are beneficial for brain health.

Answer 65

Omega-3 Fatty Acids

Question 66

Foods that are heavily processed and often contain added sugars, fats, and preservatives which are linked to an increased risk of depression.

Answer 66

Ultra-Processed Food

Question 67

Are there super foods or magic supplements?

Answer 67

No single food or supplement can guarantee positive mental health. A balanced, ongoing diet is necessary.

Question 68

What are the challenges of dietary interventions

Answer 68

1) Adherence Issues 2) Lack of Motivation or Interest 3) Comorbidity

Question 69

What are the types of Microbiota-Targeted Supplements?

Answer 69

1) Probiotics 2) Prebiotics 3) Synbiotics 4) Psychobiotics

Question 70

Food supplements containing beneficial bacteria that, when ingested in sufficient quantities, can have positive effects on our bodies. Ex. Cheeses, sauerkraut, pickled foods, ginger

Answer 70

Probiotics

Question 71

Non-digestible fibers found in food that promote the growth and activity of beneficial bacteria (probiotics). Ex. Cocoa, onion, garlic, cabbage, green bananas.

Answer 71

Prebiotics

Question 72

Supplements that combine both probiotics and prebiotics.

Answer 72

Synbiotics

Question 73

A term coined by John Cryan and Ted Dinan, referring to supplements (probiotics, synbiotics, etc.) that, when taken in sufficient quantities, can yield positive psychiatric effects.

Answer 73

Psychobiotics

Question 74

Probiotics that can positively impact mental health by influencing the gut-brain axis.

Answer 74

Psychobiotics

Question 75

Types of beneficial bacteria commonly used in probiotics.

Answer 75

Lactobacillus and Bifidobacterium

Question 76

A modern technology that allows for comprehensive analysis of genetic material, including the microbiota.

Answer 76

Next-Generation Sequencing

Question 77

The tendency to respond to sad mood with negative thoughts.

Answer 77

Cognitive Reactivity

Question 78

Initial research conducted in cell cultures or animal models to identify compounds with therapeutic potential.

Answer 78

Laboratory Studies

Question 79

How is the human phase trial conducted?

Answer 79

Phase I: Purpose: Determine the safety of a drug. Participants: A small group of healthy volunteers. Phase II: Purpose: Study the drug's efficacy and safety. Participants: A larger group, generally in the hundreds. Phase III: Purpose: Thoroughly assess effectiveness in a more representative population. Participants: Thousands of people. Duration: These phases can take up to 10 years.

Question 80

Ongoing research after a drug is approved and available to the public.

Answer 80

Post-Marketing Phase

Question 81

How does the Clinical Trials pipeline look like?

Answer 81

1) Laboratory Studies 2) Human Phase Trials 3) Post-Marketing Phase

Question 82

The ability of a compound to provide medical benefits.

Answer 82

Therapeutic Potential

Question 83

The ability of a drug to produce the desired therapeutic effect.

Answer 83

Efficacy

Question 84

Is there a connection between probiotics and antidepressants?

Answer 84

Combining probiotics with antidepressants appears more effective than using probiotics alone

Question 85

A measure of the strength of the relationship between two variables.

Answer 85

Effect Size

Question 86

A substance with no therapeutic effect used as a control in testing new drugs.

Answer 86

Placebo

Question 87

What are the effects of probiotics on other psychiatric disorders?

Answer 87

MDD: Some benefit alleviating depressive episodes Alzheimer's: Some improvement in cognitive function, mood and anxiety Bipolar Disorder: Reduce hospitalization and rehospitalization during manic episodes Autism: Minor improvements in overall behavior Schizophrenia: Potential benefits in gastrointestinal functioning and metabolic health

Question 88

Involve transferring stool from a healthy donor to a recipient to restore healthy gut microorganisms. Primarily used to treat Clostridium difficile (C. difficile) infections and some bowel diseases

Answer 88

Faecal Microbiota Transplant (FMT)

Question 89

A bacterium that causes severe diarrhea and other intestinal issues.

Answer 89

Clostridium difficile (C. difficile)

Question 90

What are the implications of FMT studies?

Answer 90

Causal Role: These studies suggest that an imbalanced microbiota can be a cause, not just a symptom, of psychiatric conditions. Caution in Clinical Use: Care must be taken when transplanting microbiota, as it can carry the "footprint" of mental illness.