Nutrition Lecture Week 7 - Advanced Exercise Physiology, Metabolism and Inflammation

Question 1

Cellular uptake of plasma CHO does not limit oxidation …

Answer 1

the major limiting step in oxidising ingestion CHO appears to be the transport across the intestinal mucosa

Question 2

Role of insulin in glucose disposal …

Answer 2

Insulin stimulates a cascade of protein activity (phosphorylation) which causes GLUT-4 transport proteins to translocate to the plasma membrane

Question 3

Muscle contraction can directly mediate cellular glucose disposal …

Answer 3

• AMPK mediated
• when both beta1 and beta2 subunits were genetically deleted, glucose uptake was reduced
• PGC-1aplha activity was incereased in the beta1/beta2 knockout
• Ca** mediated
• tetanic calcium (Ca**) release (muscle contraction) also activates AMPK
• Action of Ca2+/calmodulin dependant protein kinase

Question 4

AMPK activity is reduced in AMPKalpha2 inactive mice when …

Answer 4

CaMKK is activated

Question 5

Trained athletes use increased fat at same %VO2max …

Answer 5

at lower exercise intensity, fat oxidation increased further

Question 6

Intramuscular triacylglycerol (IMTG) utilisation is …

Answer 6

fibre type dependant

- depletion of IMTG >60% in type 1 fibres

Question 7

Increase in acetyl carnitine may inhibit CPT1 and down regulate FA entry into the mitochondria …

Answer 7

• Free carnitine reduced as increased actyl groups from acetyl CoA during high intensity exercise binds to carnitine, inhibiting CPT1
• free carnitine + acyl = acetylcarnitine = LCFA entry
• lower free carnitine = low carnitine = lower CPT 1 activitiy
  =Effect of exercise intensity

Question 8

Elevated plasma FA impairs…

Answer 8

impairs insulin signalling and intramuscular triacylglycerol oxidation

• • inhibits the insulin cascade for GLUT4 translocation - IRS1, Akt, AS160 inactivation
• • the metabolites PKC Ceramides and Fatty Acyl CoA impair the activation of insulin signalling intermediates

Question 9

Why do people with obesity liberate IMTG at a lower rate …

Answer 9

-- Insulin resistant = ↓ adipose
tissue FFA release
-- Therefore ↑ lpl activity and FFA
cellular availability
-- Greater FA oxidation by products
→ direct inhibition IMTG liberation
(adipose triglyceride lipase; agtl)
-- Exacerbated by inactivity as IMTG
turnover is reduced & FFA entry ↑
for energy storage (↑ FAT/CD36

Question 10

Why do trained athletes have more IMTG ?

Answer 10

• Due to regular depletion and enzymatic up regulation
• CPT1 activity ↑
  • ↑ type 1 fibre expression
  with training

Question 11

Niacin (vit b3)/ acipimox suppresses …

Answer 11

adipose tissue lipolysis

Question 12

Acipimox increases IMTG utilisation during exercise and is associated with …

Answer 12

improved insulin sensitivity

Question 13

Explain why Pdk 4 inhibitor reduces acetylcarnitine ?

Answer 13

• PDK 4: an enzyme responsible for
converting pyruvate to acetyl-CoA
• Remember ↑ acetylcarnitine inhibits
CPT1 (and FA entry into mitochondria
• It stands if we ↓ acetylcarnitine we
can upregulate fat oxidation (and
liberate IMTG)
• Can this be achieved by dietary
manipulation?
• Increase fat oxidation and insulin
sensitivity

Question 14

Can diet/exercise increase fat oxidation ?

Answer 14

• ↓reliance on CHO
• ↑ fat oxidation
• ↑ circulatory ketone bodies
• ↑ ketone oxidation?
• Can fat provide enough energy
to sustain higher intensity (%
VO2max)?
• What about performance?

Question 15

Inflammation is …

Answer 15

The first physiological response to harmful stimuli which is required for the healing of injured
tissue

Question 16

What are causes of inflammation ?

Answer 16

• Mechanical injury
• chemical toxins
• invasion by microorgnisms
• hypersensitivity reactions

Question 17

Why do people with obesity liberate IMTG at a lower rate …

Answer 17

-- Insulin resistant = ↓ adipose
tissue FFA release
-- Therefore ↑ lpl activity and FFA
cellular availability
-- Greater FA oxidation by products
→ direct inhibition IMTG liberation
(adipose triglyceride lipase; agtl)
-- Exacerbated by inactivity as IMTG
turnover is reduced & FFA entry ↑
for energy storage (↑ FAT/CD36

Question 18

Why do trained athletes have more IMTG ?

Answer 18

• Due to regular depletion and enzymatic up regulation
• CPT1 activity ↑
  • ↑ type 1 fibre expression
  with training

Question 19

Niacin (vit b3)/ acipimox suppresses …

Answer 19

adipose tissue lipolysis

Question 20

Acipimox increases IMTG utilisation during exercise and is associated with …

Answer 20

improved insulin sensitivity

Question 21

Explain why Pdk 4 inhibitor reduces acetylcarnitine ?

Answer 21

• PDK 4: an enzyme responsible for
converting pyruvate to acetyl-CoA
• Remember ↑ acetylcarnitine inhibits
CPT1 (and FA entry into mitochondria
• It stands if we ↓ acetylcarnitine we
can upregulate fat oxidation (and
liberate IMTG)
• Can this be achieved by dietary
manipulation?
• Increase fat oxidation and insulin
sensitivity

Question 22

Can diet/exercise increase fat oxidation ?

Answer 22

• ↓reliance on CHO
• ↑ fat oxidation
• ↑ circulatory ketone bodies
• ↑ ketone oxidation?
• Can fat provide enough energy
to sustain higher intensity (%
VO2max)?
• What about performance?

Question 23

How to attenuate inflammation ?

Answer 23

• Disrupt the cytokine response
• Prevent the inflammatory stimulus
• ibuprofen, aspirin
• n-3 & antioxidants

Question 24

What are causes of inflammation ?

Answer 24

• Mechanical injury
• chemical toxins
• invasion by microorgnisms
• hypersensitivity reactions

Question 25

What is the body's reaction to causes of inflammation ?

Answer 25

- Release of cytokines (signalling proteins) - ↑ blood supply to the affected area - capillary permeability is increased, - leucocytes migrate from the capillary vessels into the surrounding interstitial spaces to the site of inflammation or injury capillary permeability is increased

Question 26

Pro vs Anti inflammatory cytokines and proteins

Answer 26

``` • Schenk 2009 - IKK-NkB pathway increased in obese and causes insulin resistance • ↑ by FFA availability • Reversed with training - Training stimulus - ↑ inflammation - Temporary damage/disfunction to the myofibrils (actin/mysiin filaments) - ↑ protein turnover → repair ```

Question 27

Describe IL1 ( A key cytokine which activates the inflammatory response)

Answer 27

Produced by monocytes and many other cells | activate lymphocytes and many inflammatory cells

Question 28

Describe TNF ( A key cytokine which activates the inflammatory response)

Answer 28

``` • Two forms:TNFa and TNFb. • Produced by many cells including monocytes (TNFa ) . • Produced by T-cells (TNFb). • Widespread activation of cells; apoptosis, shock, cachexia ```

Question 29

Describe IL6 ( A key cytokine which activates the inflammatory response)

Answer 29

• Produced by T-cells but also by many other cells too. • Activates B & T-cells and other cell types.

Question 30

Describe Interferons (IFNs) (A key cytokine which activates the inflammatory response)

Answer 30

``` • 3 forms: a,b & g. • Produced by monocytes (a), fibroblasts (b) and T-cells (g). • Antiviral, cell activating and tumour suppressant effects. ```

Question 31

How to attenuate inflammation ?

Answer 31

- Disrupt the cytokine response - Prevent the inflammatory stimulus - ibuprofen, aspirin - n-3 & antioxidants

Question 32

Name 4 anti-inflammatory foods / food types / minerals

Answer 32

1. fibre 2. B-Carotene 3. Vitamin D 4. Garlic

Question 33

Name 4 pro-inflammatory foods / food types / minerals

Answer 33

1. saturated fat 2. cholesterol 3. Carbohydrate 4. Protein