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HSS4102[A] > M4-Lecture2 > Flashcards

M4-Lecture2 Flashcards

The microbiome in development and health

1
Q

Acondition in which the gut bacteria become imbalanced.

A

Dysbiosis

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2
Q

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.

A

True

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3
Q

There are many factors that can lead to dysbiosis:

A

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

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4
Q

Poor dental hygiene and anxiety can also lead to dysbiosis

A

True

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5
Q

See contributing factor but not cause

A
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6
Q

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

A

Gut-brain axis

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7
Q

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

A

neural, endocrine, immune, and humoral links

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8
Q

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

A

True

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9
Q

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

A

True

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10
Q

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

A

Neurotransmitters in both nervous systems

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11
Q

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

A

True

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12
Q

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

A
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13
Q

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.

A

The vagus nerve

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14
Q

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

A
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15
Q

Your gut and brain are also connected through chemicals

A

Neurotransmitters (control feelings and emotions)

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16
Q

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

A

True

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17
Q

A large proportion produced in the gut:

A

Serotonin

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18
Q

Your gut microbes also produce a neurotransmitter called

Hint: which helps control feelings of fear and anxiety

A

gamma-aminobutyric acid (GABA)

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19
Q

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

A
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20
Q

Your gut microbes produce lots of

A

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

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21
Q

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

A

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

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22
Q

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

A

True

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23
Q

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

A
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24
Q

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

A

Butyrate

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25
Q

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

A

Propionate

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26
Q

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

A

Acetate

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27
Q

See functions of SCFA

A
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28
Q

Your gut-brain axis is also connected through

A

The immune system

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29
Q

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

A

what is passed into the body and what is excreted

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30
Q

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

A

LPS

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31
Q

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

A
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32
Q

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

A
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33
Q

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

A
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34
Q

In 2021, around29 percentof adults aged 18 years and older in Canada were obese, while 36 percent were overweight.(many factors contribute).

A
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35
Q

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

A
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36
Q

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).

A
37
Q

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

A
38
Q

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

A

Diet

39
Q

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

A

True

40
Q

is an essential component to host health

A

Microbial diversity

41
Q

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

See diagram

A

True

42
Q

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

A

True

43
Q

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

A

Diet

44
Q

The microbiota of people with obesity contains lower proportions ofBacteroidetesand higher proportions ofFirmicutesthan those from people without obesity as is also seen in pregnancy

A

Yes

45
Q

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

A

True

46
Q

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

A

True

47
Q

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

A

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

48
Q

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

A

True

49
Q

See diagram

A
50
Q

Antibiotics kill both the good and the bad

A

True

51
Q

Mice treated with antibiotics gained weight.

A

True

52
Q

Antibiotics mixed with animal feed makes them grow quicker.

A

True

53
Q

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

A

True

54
Q

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

A

True

55
Q

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

A

True

56
Q

See digram

A
57
Q

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

A

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

58
Q

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

A

True

59
Q

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

A

Yes

60
Q

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

A

True

61
Q

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

A

True

62
Q

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

A

Yes

63
Q

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

A

Commensal microbes

64
Q

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

A

True

65
Q

Gut microbiota dysbiosis after disease resolution could contribute to persistent symptoms

A

True

66
Q

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

A

True

67
Q

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

A

Inflammatory Bowel Disease (IBD)

68
Q

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

A

Irritable Bowel Syndrome (IBS)

69
Q

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

A

True

70
Q

Increasing evidence shows that IBS patients are affected with higher levels of stress and a negative emotional well-being

A

True

71
Q

See diagram

A
72
Q

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.

A

True

73
Q

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

A

True

74
Q

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

A

True

75
Q

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

A

True

76
Q

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

A

FODMAPs

77
Q

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

A

Yes

78
Q

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

A

True

79
Q

See diagrams

A
80
Q

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

A

Hygiene hypothesis

81
Q

Factors at play for lack of early microbial exposure

A

cleaner living, urbanization and increased antibiotic use

82
Q

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

A

True

83
Q

See diagrams

A
84
Q

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

A

Sucralose, aspartame, and saccharin

85
Q

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

A

True

86
Q

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

A

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

87
Q

See diagram

A
88
Q
A

HSS4102[A] (13 decks)

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