Obesity and Metabolic Syndrome Flashcards
Adipose tissue can be found
Most around visceral organs
Adipose tissue is made of
adipocytes
Adipocytes are used
1) to store TAGS (triacyglycerol)
2) For lipid homeostasis and maintenance of energetic metabolism
Increase of fat mass occurs in 2 ways
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
What two tissues expand through hypertrophy and hyperplasia
1) Subcutaneous adipose tissue (SAT)
2) Vicsceral adipose tissue (VAT)
T or F: Hyperplasia has a protective effect against obesity-associated metabolic complications.
T
What happens to unhealthy individuals in terms of hyperplasia
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.
Adipogenesis and obesity (healthy vs unhealthy adipogenesis)
Energy homeostasis
Maintains amount of adipose tissue at a healthy level
Energy homeostasis
Maintains amount of adipose tissue at a healthy level
Purpose of thermic effect of food
Thermic effect of food is the energy necessary to process, digest, absorb and store nutrients in the body
T or F: Total energy expenditure over a lifetime is constant
True
Obesity BMI
BMI greater than 30, overweight (25-29.9)
Obesity (especially visceral obesity) increases the risk of developing other diseases like
-Cardiovascular disease (heart attack, stroke)
-Type II Diabetes
-Sleep apnea
-Fertility problems
-Osteoarthritis
-Cancer (Breast, colon, prostate, endometrium, kidney and gallbladder)
Adipokines
Signaling molecules important in many physiological and metabolic processes. Mostly produced by adipocytes…but also resident macrophages
Physiological and metabolic processes regulated by adipokines secreted by adipocytes
Physiological and metabolic processes regulated by adipokines secreted by adipocytes
The hypoxia theory
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.
Effects of hypoxia on the secretion of key adipokines by human adipocytes in cell culture
What is induced by hypoxia/obesity
HIF-1a (hypoxia inducible factor-1a) expression
HIF1α is linked to Cancer
Rapid growth of tumour and hypoxic conditions found by degradation of HIF1α
T or F: HIF1α regulated experssion of 1300 genes and decreases the release of which adipokine
Adiponectin
Effects of hypoxia on adipokine expression