M4-Lecture2

Question 1

Acondition in which the gut bacteria become imbalanced.

Answer 1

Dysbiosis

Question 2

Dysbiosis has been associated with diseases such asInflammatory Bowel Disease (IBD), Obesity, Diabetes, Autism, leaky gut syndrome, celiac disease, heart disease, dementia and certain gastrointestinal cancers.

Answer 2

True

Question 3

There are many factors that can lead to dysbiosis:

Answer 3

the excessive or wrong use of antibiotics, excessive alcohol consumption, increased intake of sugar or protein, frequent use of antacids, exposure to pesticides, artificial sweeteners and chronic stress

Question 4

Poor dental hygiene and anxiety can also lead to dysbiosis

Answer 4

True

Question 5

See contributing factor but not cause

Question 6

The bidirectional communication between the central nervous system and gut microbiota, referred to

Answer 6

Gut-brain axis

Question 7

Through signaling from gut-microbiota to brain and from brain to gut-microbiota by means of

Answer 7

neural, endocrine, immune, and humoral links

Question 8

Hormones, neurotransmitters and immunological factors released from the gut are known to send signals to the brain either directly or via autonomic neurons

Answer 8

True

Question 9

Studies on Germ free animals have shown that bacterial colonization of the gut is central to development and maturation of both Enteric NS and Central NS

Answer 9

True

Question 10

The absence of microbial colonization is associated to an altered expression and turnover of

Answer 10

Neurotransmitters in both nervous systems

Question 11

Studies conduced on Germ free animals have also demonstrated that microbiota influences stress reactivity and anxiety-like behavior, and regulates the set point for HPA activity

Answer 11

True

Question 12

Germ free animals, also have memory dysfunction probably to be ascribed to an altered expression of brain-derived neurotrophic factor (BDNF), one of the most important factors involved in memory

Question 13

regulates internal organ functions such as digestion, heart rate, and respiratory rate, as well as vasomotor activity, and certain reflex actions, such as coughing, sneezing, swallowing, and vomiting.

Answer 13

The vagus nerve

Question 14

Neurochemical and behavioral effects were not present in vagotomized mice, identifying the vagus as the major modulatory constitutive communication pathway between microbiota and the brain

Question 15

Your gut and brain are also connected through chemicals

Answer 15

Neurotransmitters (control feelings and emotions)

Question 16

Many of these neurotransmitters are also produced by your gut cells and the trillions of microbes living there

Answer 16

True

Question 17

A large proportion produced in the gut:

neurotransmitter

Answer 17

Serotonin

Question 18

Your gut microbes also produce a neurotransmitter called

Hint: which helps control feelings of fear and anxiety

Answer 18

gamma-aminobutyric acid (GABA)

Question 19

Studies in mice have shown that certain probiotics (Lactobacillus and Bifidobacterium) can increase the production of GABA and reduce anxiety and depression-like behavior

Question 20

Your gut microbes produce lots of

Answer 20

SCFA,such as butyrate, propionate and acetate by digesting fiber

Question 21

SCFA affect brain function in a number of ways, such as reducing appetite. How?

Answer 21

Consuming propionate can reduce food intake and reduce the activity in the brain related to reward from high-energy food

Question 22

Butyrate and the microbes that produce it are also important for forming the blood-brain barrier

Answer 22

True

Question 23

Gut microbes also metabolize bile acids and amino acids to produce unconjugated and secondary bile acids that act as signalling molecules and metabolic regulators

Question 24

is the main energy source for human colonocytes, can induce apoptosis of colon cancer cells, and can activate intestinal gluconeogenesis, having beneficial effects on glucose and energy homeostasis

Answer 24

Butyrate

Question 25

is transferred to the liver, where it regulates gluconeogenesis and satiety signalling through interaction with the gut fatty acid receptors.

Answer 25

Propionate

Question 26

the most abundant SCFA and an essential metabolite for the growth of other bacteria—reaches the peripheral tissues where it is used in cholesterol metabolism and lipogenesis, and may play a role in central appetite regulation

Answer 26

Acetate

Question 27

See functions of SCFA

Question 28

Your gut-brain axis is also connected through

Answer 28

The immune system

Question 29

Gut and gut microbes play an important role in your immune system and inflammation by controlling

Answer 29

what is passed into the body and what is excreted

Question 30

is an inflammatory toxin made by certain bacteria. It can cause inflammation if too much of it passes from the gut into the blood

Answer 30

LPS

Question 31

Data from both human and rodent studies has linked an obese phenotype to elevated circulating levels of plasma LPS

Question 32

This can happen when the gut barrier becomes leaky, which allows bacteria and LPS to cross over into the blood

Question 33

Inflammation and high LPS in the blood have been associated with a number of brain disorders including severe depression, dementia and schizophrenia

Question 34

In 2021, around 29 percent of adults aged 18 years and older in Canada were obese, while 36 percent were overweight.(many factors contribute).

Question 35

Just like other organs in the body, the microbiome can dynamically respond to a variety of internal and external physiological cues, such as food intake, energy requirements, and stress, in order to maintain a state of metabolic homeostasis

Question 36

Germ-free mice had 42% less body fat than normal mice even though the normal mice ate 29% less food/day. When germ-free mice were colonized with bacteria they increased body fat by 57% even though they ate 27% less food (↓ in lean body mass).

Question 37

In fat mice, the relative abundance of Bacteroidetes and Firmicutes was altered (↓ in Bacteroidetes).

Question 38

is a major manipulator of gut microbiome; Ex., high-fat diet- (HFD-) feeding develops microbiome dysbiosis in parallel to systemic abnormalities into the host metabolism causing obesity and type 2 diabetes

Answer 38

Diet

Question 39

The exact taxonomic composition that constitutes a “healthy” gut microbiota is still unclear

Answer 39

True

Question 40

is an essential component to host health

Answer 40

Microbial diversity

Question 41

Compared to their lean counterparts, obese individuals have a markedly lower bacterial diversity, and decreased fecal microbial gene richness See diagram

Answer 41

True

Question 42

The contribution of gut dysbiosis in obesity is well known The mechanisms are not well defined

Answer 42

True

Question 43

is a major manipulator of gut microbiome; Ex., high-fat diet- (HFD-) feeding develops microbiome dysbiosis in parallel to systemic abnormalities into the host metabolism causing obesity and type 2 diabetes  See diagram

Answer 43

Diet

Question 44

The microbiota of people with obesity contains lower proportions of Bacteroidetes and higher proportions of Firmicutes than those from people without obesity as is also seen in pregnancy

Answer 44

Yes

Question 45

Most studies of overweight and obese people show a dysbiosis characterized by a lower diversity

Answer 45

True

Question 46

Germ-free mice that receive faecal microbes from obese humans gain more weight than mice that receive microbes from healthy weight humans.

Answer 46

True

Question 47

Gut microbiota dysbiosis probably promotes diet induced obesity and metabolic complications by a variety of mechanisms including

Answer 47

(I) Immune dysregulation (II) Altered energy production (III) altered gut hormone regulation (IV) pro-inflammatory (like LPS crossing endotoxins crossing gut barrier - to circulation

Question 48

Randomized controlled trials have shown that higher production of SCFAs correlates with lower diet-induced obesity and with reduced insulin resistance

Answer 48

True

Question 49

See diagram

Question 50

Antibiotics kill both the good and the bad

Answer 50

True

Question 51

Mice treated with antibiotics gained weight.

Answer 51

True

Question 52

Antibiotics mixed with animal feed makes them grow quicker.

Answer 52

True

Question 53

Children treated with antibiotics during the first 6 months have a 22% higher probability of being obese at 3 years.

Answer 53

True

Question 54

Helicobacter pylori appears to lower risk of developing asthma and allergies.

Answer 54

True

Question 55

It may have been a “normal” bacteria many years ago. Its loss may be associated with acid reflux

Answer 55

True

Question 56

See digram

Question 57

Why do some people have really poor outcomes and others are almost asymptomatic? What is different between these individuals?

Answer 57

Risk factors for poor outcome include age and metabolic disorders such as obesity and type 2 diabetes

Question 58

The well-known comorbidities of COVID-19 are all associated with dysbiosis

Answer 58

True

Question 59

1918 pandemic caused a cytokine storm in healthy individuals, while this one causes a cytokine storm in unhealthy individuals.

Answer 59

Yes

Question 60

Infection with SARS-CoV2 can cause excessive inflammation with enhanced production of cytokines and interferons leading to severe disease with poor outcomes

Answer 60

True

Question 61

COVID-19 may also cause epithelial barrier dysfunction enhancing damaging inflammatory responses

Answer 61

True

Question 62

But healthy microbiota (variety and volume) can prevent the effects of COVID-19

Answer 62

Yes

Question 63

microbes are beneficial microbes that directly act on the host immune system to prevent invasion and colonization of pathogenic microbes

Answer 63

Commensal microbes

Question 64

Within one week of COVID-19 infection, they observed a reduction in alpha diversity in the gut microbiome

Answer 64

True

Question 65

Gut microbiota dysbiosis after disease resolution could contribute to persistent symptoms

Answer 65

True

Question 66

fecal bacteria transplantation (FMT), prebiotics, and probiotics may play a positive role in the treatment of COVID-19 and reduce the fatal consequences of the disease

Answer 66

True

Question 67

Is traditionally divided into Crohn's disease (CD) and ulcerative colitis (UC)

Answer 67

Inflammatory Bowel Disease (IBD)

Question 68

is one of the most common gastrointestinal (GI) disorders and the bacterial role has been largely investigated

Answer 68

Irritable Bowel Syndrome (IBS)

Question 69

Fecal and colonic mucosal biopsy samples from IBS patients and healthy controls demonstrated a significant reduction in the concentration of aerobic bacteria such as the Lactobacillus species in fecal samples from IBS patients compared to healthy controls

Answer 69

True

Question 70

Increasing evidence shows that IBS patients are affected with higher levels of stress and a negative emotional well-being Also, pre & post natal factors diet flora changes prior infection gut-brain axis

Answer 70

True

Question 71

See diagram

Question 72

Under normal circumstances, mucus epithelium barrier confines microbes to the epithelial surface or intestinal lumen where homeostatic immune responses are induced to maintain barrier integrity and tolerance among commensal microbes.

Answer 72

True

Question 73

Once the barrier is breached by influx of inflammatory mediators, pathogens or any agents that provoke intense immune reactions, severe inflammation occurs and this will affect the intestinal environment, and changes the gut microbiota composition

Answer 73

True

Question 74

Combination of low grade mucosal inflammation with visceral hypersensitivity and impaired bowel motility could be the underlying etiology for IBS pathogenesis

Answer 74

True

Question 75

Reduction in the intake of foods that are high in fermentable oligosaccharides, disaccharides, and monosaccharides and polyols (FODMAP) reduces GI symptoms and improves disease-specific quality of life in patients with IBS. At least 86% of patients with IBS report symptomatic benefit

Answer 75

True

Question 76

are short-chain carbohydrates that are easily fermentable by gut bacteria into methane and hydrogen gasses but are poorly absorbed

Answer 76

FODMAPs

Question 77

Dysbiosis was found significantly greater in patients with CD than with UC, as shown by a more reduced diversity, a less stable microbial community and eight microbial groups were proposed as a specific microbial signature for CD

Answer 77

Yes

Question 78

Although UC and CD share many epidemiologic, immunologic, therapeutic and clinical features, our results showed that they are two distinct subtypes of IBD at the microbiome level

Answer 78

True

Question 79

See diagrams

Question 80

Which hypothesis states that the lack of early microbial exposure may reduce tolerance of the adaptive immune response

Answer 80

Hygiene hypothesis

Question 81

Factors at play for lack of early microbial exposure

Answer 81

cleaner living, urbanization and increased antibiotic use

Question 82

Several studies demonstrated that gut microbiota composition is altered in patients suffering from T2D, but it is not clear whether these changes are a cause or simply a consequence of the disorder

Answer 82

True

Question 83

See diagrams

Question 84

have been shown to disrupt the balance and diversity of gut microbiota

Answer 84

Sucralose, aspartame, and saccharin

Question 85

Food additives, such as emulsifiers, which are ubiquitous in processed foods, have also been shown to affect the gut microbiota in animals

Answer 85

True

Question 86

Other areas of concern include the side effects of popular restrictive diets on gut health. These include

Answer 86

These include some strict vegan diets, raw food or “clean eating” diets, gluten-free diets, and low FODMAP (fermentable oligosaccharides, disaccharides, monosaccharides, and polyols) diets used to treat irritable bowel syndrome

Question 87

See diagram