Obesity and Metabolic Syndrome

Question 1

Adipose tissue can be found

Answer 1

Most around visceral organs

Question 2

Adipose tissue is made of

Answer 2

adipocytes

Question 3

Adipocytes are used

Answer 3

1) to store TAGS (triacyglycerol)
2) For lipid homeostasis and maintenance of energetic metabolism

Question 4

Increase of fat mass occurs in 2 ways

Answer 4

1) Hyperplasia: Enlargment of an organ or tissue because of cell proliferation (more cells)
2) Hypertrophy: Enlargment of an organ or tissue from increase in size of its cells

Question 5

What two tissues expand through hypertrophy and hyperplasia

Answer 5

1) Subcutaneous adipose tissue (SAT)
2) Vicsceral adipose tissue (VAT)

Question 6

T or F: Hyperplasia has a protective effect against obesity-associated metabolic complications.

Answer 6

T

Question 7

What happens to unhealthy individuals in terms of hyperplasia

Answer 7

1) In unhealthy obese individual, hyperplasia of adipocytes in SAT is compromised, limiting the storage capacity of fatty acids.
2) The excess lipids will be stored in VAT as well as ectopic tissues, leading to lipotoxicity.
3) The lipotoxicity will take multiple forms: hypoxia, inflammation, insulin resistance which causes
Metabolic syndrome, type 2 diabetes, heart disease.

Question 8

Adipogenesis and obesity (healthy vs unhealthy adipogenesis)

Answer 8

Question 9

Energy homeostasis

Answer 9

Maintains amount of adipose tissue at a healthy level

Question 9

Energy homeostasis

Answer 9

Maintains amount of adipose tissue at a healthy level

Question 10

Purpose of thermic effect of food

Answer 10

Thermic effect of food is the energy necessary to process, digest, absorb and store nutrients in the body

Question 11

T or F: Total energy expenditure over a lifetime is constant

Answer 11

True

Question 12

Obesity BMI

Answer 12

BMI greater than 30, overweight (25-29.9)

Question 13

Obesity (especially visceral obesity) increases the risk of developing other diseases like

Answer 13

-Cardiovascular disease (heart attack, stroke)
-Type II Diabetes
-Sleep apnea
-Fertility problems
-Osteoarthritis
-Cancer (Breast, colon, prostate, endometrium, kidney and gallbladder)

Question 14

Adipokines

Answer 14

Signaling molecules important in many physiological and metabolic processes. Mostly produced by adipocytes…but also resident macrophages

Question 15

Physiological and metabolic processes regulated by adipokines secreted by adipocytes

Answer 15

Question 16

Physiological and metabolic processes regulated by adipokines secreted by adipocytes

Answer 16

Question 17

The hypoxia theory

Answer 17

1) As adipose tissue mass expands (obesity), groups of adipocytes will become more and more distant to blood vessels.
2) Increase in adipose tissue does not lead to an increase in blood flow to this tissue
3) Hypertrophic adipocytes (150-200mm in diameter) are larger then the normal diffusion distance of O2 (100-200mm in diameter)
4) Under hypoxic conditions, a variation of expression in adipokines is observed.

Question 18

Effects of hypoxia on the secretion of key adipokines by human adipocytes in cell culture

Answer 18

Question 19

What is induced by hypoxia/obesity

Answer 19

HIF-1a (hypoxia inducible factor-1a) expression

Question 20

HIF1α is linked to Cancer

Answer 20

Rapid growth of tumour and hypoxic conditions found by degradation of HIF1α

Question 21

T or F: HIF1α regulated experssion of 1300 genes and decreases the release of which adipokine

Answer 21

Adiponectin

Question 22

Effects of hypoxia on adipokine expression

Answer 22

Question 23

explain obesity and metabolic syndrom

Answer 23

Metabolic syndrome is a cluster of conditions — increased blood pressure, high blood sugar, excess body fat around the waist, and abnormal cholesterol or triglyceride levels — that occur together, increasing your risk of heart disease, stroke and diabetes. (Mayo Clinic)
Group of risk factors that raises your risk for heart disease and other health problems.

Question 24

What are 3 mdtabolic consequences of obesity

Answer 24

1) Regulation of body weight 2) Inflammation 3) Insulin resistance

Question 25

T or F: Leptin regulates body weight

Answer 25

True

Question 26

Leptin

Answer 26

An adipokine secreted by the adipose tissue that is involved in multiple processes including the control of appetite, the rate of of b-oxidation and FA synthesis in the various tissues.

Question 27

Control of appetite by leptin

Answer 27

Question 28

What happens if we remove the LEP (Leptin) gene from a mouse genome

Answer 28

Mice become obese Suffer from hyperphagia (abnormal increase in appetite)

Question 29

What happens if we remove the LEP (Leptin) gene from a mouse genome

Answer 29

Mice become obese Suffer from hyperphagia (abnormal increase in appetite)

Question 30

t or F: Obese individuals do not develop resistance to leptin

Answer 30

False they do and leptin is a long term response so have increased leptin but stop responding (hyperleptinaemia)

Question 31

Obesity and inflammation

Answer 31

Question 32

Obesity and inflammation

Answer 32

Question 33

TNF-α is secreted by

Answer 33

adipose tissue-resident macrophages

Question 34

Action of TNF-α (pro inflammatory response)

Answer 34

1) Stimulates lipolysis 2) TNF-α counteracts the action of insulin (prevents binding to the receptor and lowers the expression of GLUT4) 3) Block the entry of new free fatty acid. 4)Decrease TAG biosynthesis through inhibition of the peroxisome proliferator-activated receptor gamma (PPARγ)

Question 35

Summary of Action of TNF-a in regars to Insulin signaling

Answer 35

1) The TNF-α pathway stimulates the expression of proinflammatory genes but also blocks the downstream activation of insulin signalling by inhibiting the kinase activity of IRS1. 2) IRS1 can be destabilized by the Interleukin-6 (IL-6) signaling cascade. 3) Higher concentrations of IL-6, which is an adipokine, are observed in obese individuals.

Question 36

Explain the interleukin-6 (IL-6) paradox

Answer 36

1) In healthy subjects, 10-35% of the circulating IL-6 is produced by adipose tissue (mainly by adipose resident macrophages).Levels of IL-6 increase in response to acute and low-grade chronic inflammation.It was shown that a transient/acute expression of IL-6 in response to exercise was causing an increase in sensitivity to insulin. 2) On the other hand, multiple studies have also shown that chronic elevated level of IL-6 was leading to a decrease in insulin sensitivity. Obese individuals display a chronic elevated level of IL-6.

Question 37

Explain obesity and m,etabolic consequences (insulin resistance)

Answer 37

obesity leads to an adipokines imbalance, which in turn causes the body to be in a proinflammatory state. Over time, it will cause cells/organs to become insulin resistant. Insulin resistance will develop into type 2 diabetes.

Question 38

Effects of insulin

Answer 38

Question 39

3 consequences of insulin resistance

Answer 39

Question 40

Adiponectin (Acrp30)

Answer 40

Peptide hormone (adipokine) produced uniquely in adipose tissue.

Question 41

Function of adiponectin (Acrp30)

Answer 41

When add adiponectin back = decrease gluconeogenesis and can use glucose again

Question 42

Adiponectin is [blank] in obese indivdiuals and why

Answer 42

Decreased because adiponectin is secreted by visceral fat which obese levels have decreased levels of (VAT and SAT communicate with one another) so if one decreases the other increases

Question 43

T or F: Adiponectin decreases insulin sensitivity

Answer 43

False, increases

Question 44

Adiponection can bind to 2 receptors

Answer 44

1) AdipoR1 2)AdipoR2

Question 45

AdipoR1

Answer 45

-Expressed mainly in the liver, muscle and hypothalamus -Function: Activation of AMPK. -Binds to the globular portion of adiponectin

Question 46

AdipoR2

Answer 46

-Expressed mainly in the liver, WAT and vasculature. -Function: Activation of PPAR (α, δ, γ) -Binds to the full-length adiponectin

Question 47

Adiponectin activates

Answer 47

1)AMPK 2)PPAR

Question 48

Roles of adiponectin

Answer 48

Question 49

How does adiponectin protect against atherosclerosis

Answer 49

= prevents inflammation

Question 50

Obesity [blanks] PPARs concentration

Answer 50

decreases

Question 51

Function of PPARs

Answer 51

These transcription factors respond to change in lipids coming from the diet by regulating the expression of genes involved in fat and carbohydrates.Their translocation to the nucleus requires the binding of a fatty acid (or fatty acids derivatives).

Question 52

Function of PPARs

Answer 52

These transcription factors respond to change in lipids coming from the diet by regulating the expression of genes involved in fat and carbohydrates.Their translocation to the nucleus requires the binding of a fatty acid (or fatty acids derivatives).

Question 53

3 types of PPAR and function

Answer 53

Question 54

3 types of PPAR and function

Answer 54

Question 55

PPARy is essential for the differentiation of

Answer 55

preadipocytes

Question 56

Summary of regulation of inflammation, insulin resistance, and atherosclerosis in terms of obesity

Answer 56

Question 56

Summary of regulation of inflammation, insulin resistance, and atherosclerosis in terms of obesity

Answer 56