Feast or Famine (5/13)

Question 1

What does leptin do?

Answer 1

Leptin is secreted by adipose cells and acts in hypothal to suppress feeding, inc energy expenditure and dec body wieght and fat. It works by inhibiting NPY and AGRP and stimulating alpha MSH (which binds MC4R receptor to inhibit food intake)

Question 2

What is ghrelin

Answer 2

Acts on brain to stim feeding and gastric motility. Feeding inhibits ghrelin

Question 3

Where does lipid accumulate in obesity? What does it lead to?

Answer 3

Liver, muscle, pancreas leading to a predisposition toward inflammation and organ dysfxn (insulin resistance)

Question 4

What predisposes to obesity?

Answer 4

The fact that hunger/satiety, fuel homeostasis, metabolic rate, and hormones are controlled by polygenic factors

Question 5

What single-gene mut can cause obesity?

Answer 5

• Leptin deficiency (leptin gives feedback inhibition to brain to supp feeding and inc energy expenditure)–>reversed via leptin injections
• Loss of MC4R (binds alpha-MSH, a factor stimulated by leptin that inhibits food intake)

Question 6

How do we know environmental factors must play a role in obesity?

Answer 6

Obesity rates have inc 3x worldwide from 1980-2008

Question 7

What environmental factors have contributed to inc in obesity?

Answer 7

• Ave caloric intake inc
• Food portions inc
• Energy density inc (cal/g)

Question 8

Who is more at risk for diabetes, sleep apnea, CVD and cancer?

Answer 8

Ppl with high BMI, abdnominal fat, depostiion, sarcopenia (loss of muscle), inc age

Question 9

What is steatosis

Answer 9

Fat storage in other tissues, result of obesity

Question 10

What are the consequences of steatosis?

Answer 10

Inc oxidative stress, mitochondrial dysfxn and ER stress in the cell which can inhibit insulin signaling, cause inlammation

Question 11

How does orlistat work vs other wt loss drugs?

Answer 11

Orlistat blocks abs of dietary fat, all others are aneorexants

Question 12

What are the 3 kinds of bariatric surgery?

Answer 12

• Adjustable gastric banding
• Vertical sleeve gasteectomy (remove 40% of stomach)
• Roux en Y gastric bypass: surgery shunts food directly from stomach to lower intestine (most effective)

Question 13

What is cachexia?

Answer 13

WAsting syndrome resulting from cancer and chronic diseases

Question 14

How are anorexia and cachexia different?

Answer 14

Inflammatory cytokines are seen in cachexia, but not other states, similar to chronic inflammation

Question 15

How do we manage cachexia?

Answer 15

• Controlled refeeding
• Diagnose underlying dis
• Anabolic rx like megesterol