sachinwalla usyd research

8/8/2019 Sachinwalla USYD Research

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1H-MRS:muscle


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1H-MRS:effect of starvation on IMCL

72 h starvation n = 6 endurance trained men

Results Vastus lateralis IMCL starvation

Plasma [FFA] starvation

Conclusion Healthy response to starvation

involves increased adiposelipolysis. Resulting increase inFFAs leads significantaccumulation of IMCL.Suggests an adaptive responsewhen muscle substrate

availability (glycogen)challenged

J Physiology ,2002 283-1185


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1H-MRS:effect of diet CHO on IMCL and

exercise

Low CHO/high fat diet n = 6 endurance trained men

48 h low CHO diet vs. normalhigh CHO

3 h cycling exercise (MRS pre-and post-)

Results Vastus lateralis IMCL low CHO

Vastus lateralis IMCL reducedduring exercise in bothconditions

Net change in IMCL greater inlow CHO associated with

higher fat oxidation duringexercise

J Applied Physiology ,2003 94 136


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1H-MRS:hepatic lipid composition

Hepatic 1H-MRS n = 27 men

Lean

Obese

Obese with hepatic steatosis (NAFLD)

Results Lipid methylene resonance vs.

other resonances increased inNAFLD

Conclusion Hepatic lipid saturation can be

inferred non-invasively

Saturation increases in NAFLD

Hepatology 2008 , -47 1513


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1H-MRS:hepatic lipid & exercise training

Hepatic 1H-MRS n = 19 obese adults NAFLD

Previously sedentary

4 weeks supervised exercise

trainingResults

Hepatic lipid in exercise-trained vs. placebo (mean21%)

Associated with lower visceraladiposity (MRI)

Despite no weight loss

Conclusion Regular exercise ameliorates

Hepatology 2009 , -50 1105


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31 - :MRS( )uscle exercise apparatus


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1

2

4 5

1 - Pi

2 - PCr

3 - Gamma ATP

4 - Alpha ATP

5 - Beta ATP

3


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Stop Exercise


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31P-MRS:muscle metabolism

Pilot Study 1 Trained (n = 1),

moderately trained (n =2) and sedentary men (n

= 1) (25-40yrs) 30, 45, 60% MVC

3 s:1 s work:rest 60, 120, 180, 210 sec

(12 workloads)Pilot Study 2

Control vs. 6 days creatineloading

Cross-over (n = 4)


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Post-processing ADP, PCr raw data

best fit (sum of squares)

concentrations

based on ATP 8.1 mmol/L

[TCr] = 0.61 x [PCr]

[ADP] = [ATP] x {([TCr]/[PCr])-1}/KCK[H+])

31 - :M R Su scle m e ta b o lism


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30% 3 min

60% 3 min

31 :M R S (u scle m e ta b o lism d u rin g)xe rcise


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30% 3 min

60% 3 min

31 :M R S ( -u scle m e ta b o lism p o st)xe rcise


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30% 3 min

60% 3 min

31 :M R S ( -u scle m e ta b o lism p o st)xe rcise


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Results:change in [PCr]

ADP(Cr)


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Results:change in pH

ADP(Cr)

Results:


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Results:effect of training status (Vinit vs

ADP)

ADP(Cr)


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Results:effect of training status

ADP(Cr)

Results:


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Results:effect of training status (PCr

resyn. Vs [ADP])

ADP(Cr)


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Results:in vivo mitochondrial kinetics

Mitochondrial kinetics Skinned Fibres

Supraphysiological ADP

Zoll et al 2002

Conclusion By varying exercise dose,

relationship between end-ex ADP and initial PCrresynthesis rate obtained

Suggest non-invasivemeasure of musclemitochondrial sensitivity

This pilot in vivo data ?


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Background:creatine / PCr shuttle

Tonkonogi & Sahlin1998

J Physiol 510: 279-286

Cr/PCr shuttle inmitochondrialrespiration

Skinned muscle fibres ADP (with/without

Cr)

Conclusion Mito respiration rate at

K u zn e tso v e t a l 1 9 9 6

Results:


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Results:creatine supplementation(PCr

resyn. Vs [ADP])

ADP(Cr)

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