17. sarcopenia and sarcopenic obesity

Question 1

sarcopenia definition

Answer 1

sarco = muscle
penia = lack of

• loss of muscle and strength

Question 2

sarcopenia leads to

Answer 2

• neuromuscular impairment
• loss mobility
• balance problems
• increase falls
• hospitalization (causes more muscle loss)
• viscous cycle

Question 3

sarcopenia normal vs disease

Answer 3

occurs naturally with aging

clinical problem once a threshold in muscle loss and strength

Question 4

body composition methods to quantify sarcopenia

Answer 4

CT / MRI / DXA

- to charaterize specific tissue mass and changes in tissue

Question 5

defining sarcopenia

Answer 5

2 standard deviations below mean for young health adult
- sex specific

• definition evolving

Question 6

sarcopenia: muscle mass vs strength

Answer 6

mass easier to define

strength no accepted criteria

• but easier to measure and is important
• mass doesnt equal strength

Question 7

aging sarcopenia - mass vs strength

Answer 7

strength decrease higher rate than mass
- quality of muscle 
- force per unit cross sectional area
- decrease fiber size and number
- contratile activity in intact fibers
- fat infilltration
- impaired neurlogical modulation 
and
**decreased metabolic quality

Question 8

high quality of muscle

- metablic perspective

Answer 8

high oxidative capacity

high capacity of glucose transport and lipid transport

Question 9

metabolic syndrom

Answer 9

cluster of metabolic abnormalities in a person that increases CVD risk

relate back to insulin resistance

• hypertension
• dyslipidemia
• diabetes

Question 10

sarcopenic obesity

- why is it new

Answer 10

aging population
more obesity

• ** silent condition
• increase fat while decrease muscle
• minimal change in BMI

Question 11

“normal” age-related changes in body composition

Answer 11

• increase fat mass from birth (peak 60-75)
• difference in partitioning of adipose
• visceral fat and intramuscular fat increase
• subcutaneous same or decrease
• fat inflitration into muscle -> lowers strength

Question 12

muscle and fat mass relation

Answer 12

more fat, need more muscle

• mechanical loading effect
• 1kg increase adipose needs 0.1 kg (women) or 0.24kg (men) skeletal muscle
• muscle mass and strength decline steadily around 30y (accelerate around 50-60y)
• 1-2% per y past 50

Question 13

problem with aging and sarcopenic obesity

Answer 13

excess fat with low muscle mass and strength

- obesity in elderly acts “synergistally” with sarcopenia to maximize disability

Question 14

factors implicated in sarcopenic obesity

Answer 14

nutrition

• low protein = sarcopenia
• increased kcal = obesity

physical activity

• atrophy from not using
• reduced kcal expenditure

low grade inflamation

• cytokines/adipokines obesity related insulin resistance
• proinflammatory cytokines = muscle catabolism

insulin resistance

• decrease resp to anabolic stim
• vasodilatory - aminos to muscle for prot syn

hormonal
- decreased growth hormone and testosterone

Question 15

muscle fat relation during weight gain

Answer 15

adipose tissue
- adiponectin decrease
- leptin increase
- TNFa increase
- IL-6 increase
- MCP-1 increase
causes macrophage recruitment
- increase inflammation
- increase adipokin release

effect on muscle

• increase inflammation
• increase fat infiltration
• causes weakness
• decrease exercise

*viscous cycle

Question 16

intervention target for sarcopenic obesity

Answer 16

increase muscle while decrease fat
- strength and aerobic exercise

target low grade inflammation