TEST 4: Obesity Flashcards
Obesity overview
(Lecture, p. 723)
-A metabolic disorder that develops when calorie intake exceeds caloric expenditure in genetically susceptible individuals
-In adults, obesity= BMI > 30
-Class 1: BMI 30 to < 35
-Class 2: BMI 45 to < 40
-Class 3: BMI > 40 “severe”
-In kids:
-BMI > 95th percentile for age and gender
—120% of 95% peregrine or greater OR 35 kg/m2 or greater
Obesity overview
(Lecture, p. 723)
-A metabolic disorder that develops when calorie intake exceeds caloric expenditure in genetically susceptible individuals
-In adults, obesity= BMI > 30
-Class 1: BMI 30 to < 35
-Class 2: BMI 45 to < 40
-Class 3: BMI > 40 “severe”
-In kids:
-BMI > 95th percentile for age and gender
—120% of 95% peregrine or greater OR 35 kg/m2 or greater
Adipose tissue
(P. 723)
-Provides insulation and mechanical support
-Body’s major energy reserve to fuel other tiessuss
4 types:
-White
-Brown
-Beige
-Bone marrow
GEM- MOST fat in the body is white
White adipose tissue
(P. 723)
-Comprises the majority of adipose tissue
-Located in visceral (central) and subcutaneous (peripheral) stores
-Contributes to the regulation of energy homeostasis:
-Adipocytes are fat storing cells that store energy as triglycerides, synthesize it from glucose, and mobilize energy from free fatty acids and glycerol
-Secrete adipokines (hormone like cytokines) that are secreted to regulate metabolic function and immune response
Adipokines deregulated vs.
Adipocytes regulated
Adipokines:
Leptin, adiponectin, resistin, RBP-4 when deregulated:
-HTN, CVA. Obesity, arthritis, DM, Arthritis, metabolic syndrome, NASH
Adipocytes when regulated (a million types listed):
-Appetite, satiety, insulin sensitivity, fat distribution, energy, blood pressure, metabolic health
White adipose tissue
(P.723)
When the energy balance is positive, excess fat is stored in white Adipocytes:
-Cells hyper trophy and become hyper plastic
-Causes dysregulation of adipokines—> pro inflammatory state and altered lipid metabolism—> contributes to obesity comorbidities
Altered Adipocytes—> insulin resistance (lipolysis and release Of FFA)—> macrophage infiltration (TNF-alpha and IL-6)
Other adipose tissues
(P.723)
Brown:
-Composed of mitochondria and iron (brown color)
-Generates heat (higher in neonates than adults)
-Does not play a role in appetite or satiety (no negative metabolic effects)
-No shivering thermogenesis
Beige:
-Appears in extreme cold or with exercise
-Protective against obesity, increases energy expenditure and weight loss
Bone marrow adipose tissue:
-In all bones (particularly long bones)
-Releases adipokines with osteoblast activity (excess osteoporosis and inflammation associated with RA)
Appetite and satiety
-Controlled by arcuate nucleus in the hypothalamus (responsibly for balancing metabolism)
Orexins= appetite stimulation
Anorexins = appetite inhibitor
Orexins
(P. 727)
Ghrelin:
-Produced in the stomach in response to hunger
-Ghrelin receptors in hypothalamus—> growth hormone that—> release gastric acid, increases GI motility, pancreatic secretion of insulin
-Lean people: elevate with hunger and fall after eating
-In obesity: levels remain elevated after eating (increased body weight and fat mass)
Endocannabinoids:
-Produced in the brain and peripheral nerves
-Increases appetite, nutrient absorption and lipogenesis
-Increases peripheral and central adipose tissue accumulation
Anorexins
(P.726)
Leptin:
-Produced by Adipocytes, acts on hypothalamus
-Decreases appetite and energy expenditure
-As Adipocytes increase, Leptin secretion increases
High levels of Leptin lose effectiveness (Leptin resistance) —> disrupts hypothalamus signals of satiety—> overeat—> increased weight
Glucagon-like Peptide-I :
-Stimulates pancreatic glucose dependent insulin secretion
-Decreases gastric emptying—> decreased appetite and increased satiety
Adiponectin
(P. 726)
-An Anorexin, increases energy expenditure
-Has insulin sensitizing and anti inflammatory properties
-Levels will decrease in obesity—> increased insulin resistance, increased CAD risk, and increased inflammatory markers.
Shifts in obesity from normal
Hunger
Ghrelin and endocannabinoid—> does NOT decrease after eating, so you lose the feedback loop to trigger hunger (increases appetite)
Leptin, GLP-I, adiponectin—> levels are high but three lower is resistance, so you lose the signal to stop eating, lose the satiety sensor, and lose protective properties
Apple V pear shape obesity
Apple:
-VISCERAL obesity: accelerated lipolysis, increased inflammation and metabolic syndromes
Pear:
-PERIPHERAL obesity: fat is less metabolically active, releases fewer adipocytokines—> risk of obesity is less severe
Obesity as multi-system syndrome
-Chronic complications are associated with > 200 health conditions
-Underlying etiologies: chronic inflammation, metabolic disorders, increased free fatty acids
Cardiovascular: Atherosclerosis, HTN, CAD, HF, renal disease, CVA
Cancer: Breast, colon, renal, stomach, pancreatic, liver, ovarian/ endometrial
GI: GERD, gallstones, fatty liver
Pulmonary: Sleep apnea, asthma exercise intolerance
Musculoskeletal: osteoarthritis, back pain, plantar fasciitis
Endocrine: insulin resistance, type 2 DN,
Infertility
Obesity treatment
-Is a chronic, relapsing disease
Treatment focus areas:
-Address metabolic abnormalities
-Lifestyle change
-CBT/ support groups
-GLP-I and GIP receptors agonists
-Bariatric surgery (Gastric bypass, roux-en-Y, gastric banding, gastric sleeve)
