Transcript Nonessential Amino Acid Metabolism in Healthy Adult Males Using

Nonessential Amino Acid
Metabolism in Healthy Adult
Males
Leah Cooper
Department of Pediatrics, University of British Columbia
& Child and Family Research Institute, BC Children's
Hospital
Outline
 Background
 Protein
 Amino Acids
 Indicator Amino Acid Oxidation Technique
 Objective & Hypothesis
 Methods
 3 Steps in Study
 Results
 Conclusion
 Future Directions
Background - Protein
 Structural component of the
body
 Enzymes, Hormones,
Neurotransmitters, Transport
Molecules
 Made of 20 Amino Acids
 Need all 20 in correct
proportions for protein synthesis
to occur in the body
www.onlymyhealth.com
Background – Amino Acids
www.thehealthsite.com
www.rpi.edu
Background - Evolution
http://www.nature.com/scitable/topicpage/an-evolutionary-perspective-on-amino-acids-14568445
Background - Nitrogen
 Play many metabolic roles in
the body
 The requirement for total
nitrogen is the primary
determinant of total protein
requirement
 If total amino nitrogen is
inadequate, synthesis of
nonessential amino acids and
thus protein is less than maximal
Background – Nitrogen Supply
 Some nonessential amino acids (NEAA) may supply
nitrogen better than others
 Rose et al. (1948) showed increased growth by 7075% in rats fed essential amino acids (EAA) + NEAA
 Rechcigl et al. (1957) showed different growth rates
in rats
 Glutamate gave the largest increase in growth
 Followed by Alanine, Aspartate, Asparagine, Proline, and
Glutamine
 Smallest increases in growth were Glycine and Serine
Background - Indicator Amino Acid
Oxidation Technique
 Previous Methods (N balance)
were long in duration, very
invasive and impractical
 The stable isotope based IAAO is
rapid, minimally invasive and
accurate
 IAAO measures the oxidation of
the tracer 13C-PHE to 13CO2 in
breath
 Oxidation is inversely proportional
to protein synthesis
 High Oxidation = Low Protein
Synthesis
Objective:
To determine the metabolic demand of 9 of the NEAA
using the indicator amino acid oxidation (IAAO) method
in healthy adult males
Hypothesis:
There will be a hierarchy among the 9 NEAA, more
specifically Alanine, Arginine, Asparagine, Aspartate,
Glutamine, Glutamate, Glycine, Proline, and Serine, to
supply Nitrogen to the body for the de novo synthesis of
the other NEAA and for protein
Methods
Preliminary
Study
Adaptation
Study Day
Preliminary Study
 Target Population:
 Healthy adult males
 Between the ages 20-40
 classified as normal body weight
and BMI (18.5-25 kg/m2)
 Background Information:
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Medical & Dietary histories
Anthropometric measurements
Body composition
Resting energy expenditure (REE)
Informed consent
Methods
Preliminary
Study
Adaptation
Study Day
Adaptation
 2 days prior to each study day
 Adaptation diets contain a
protein intake of 1.0 g/kg and a
caloric intake of 1.7 × REE
 Provided as 6 milkshakes.
products.nestle.ca
Methods
Preliminary
Study
Adaptation
Study Day
Study Day Diet
 10 Study Days
 Randomized
 Diet:
 The Base Diet (0.34
g/kg/day)
Study Day 1
Base +
ALA
Study Day 2
Week 1
BASE
(EAA)
Study Day 3
Week 2
Base +
SER
 Only EAA
 The Base Diet + 1 NEAA (0.73 Study Day 4
g/kg/day)
 50:50 ratio of EAA: NEAA
 5th Meal starts the isotope
tracer protocol with an oral
dose of L-1-13CPhenylalanine
Base +
GLN
Study Day 5
Week 4
BASE
+ PRO
Study Day 6
Week 5
Etc…for 10 weeks
Base +
ARG
Study Day Sampling
 Sample Collection
 Breath and Urine
 Baseline
 Isotopic Steady State
 Carbon dioxide production
(VCO2)
Sample Analysis & Statistics
Multi-flow
Continuous Isotope Ratio
Mass Spectrometer
 13CO2 oxidation values analyzed using repeated
measures ANOVA (Graphpad PRISM)
Results – 50 Study Days
Tracer Oxidation
1.2
1
0.8
0.6
0.4
0.2
0
*
Means ± SD
Conclusion
• The first study to look at
NEAA in humans
• We suggest all NEAA can
satisfy the metabolic
demand for total nitrogen.
Future Directions
 Determine whether a
difference in NEAA
metabolic demand exists
in more vulnerable
populations
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Acknowledgments

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Dr. Rajavel Elango
Lab members
Ajinomoto Inc. Co.
Child and Family Research
Institute
 University of British
Columbia
 All my participants!
References
 Rose, W.C., Oesterling, M.J., and Womack, M. (1948).
Comparative growth on diets containing ten and nineteen amino
acids with further observations upon the role of glutamic and
aspartic acids. J Biol Chem 176: 753-762.
 Rechcigl Jr., M., Loosli, J. K., Williams, H. H. (1957). The net
utilization of non-specific nitrogen sources for the synthesis of
non-essential amino acids I. Growth and nitrogen utilization. J
Nutr 63: 177-192.
 Millward DJ. Methodological considerations. Proc Nutr Soc
2001;60: 3–5.
 Food and Agriculture Organization of the United Nations. Energy
and Protein Requirements (1991).
QUESTIONS ??
Thank you for listening !!
Study Day Base Diet
Study Diet
Glu
Gln
Ala
Gly
Se r
NH3
CO2
Cys
Trp
Thr
Carbamoyl-PO4
Alanine
Urea
Pyruvate
Ile
Leu
Lys
Thr
Trp
Leu
Tyr
Phe
Ornithine
a-ketoglutarate
UREA
CYCLE
Arginine
Citrulline
Glutamate
Asp
Asn
Acetyl CoA
Acetoacetate
Fatty Acids
Asparate
Arginionsuccinate
Oxaloacetate
Citrate
Malate
Fumarate
TCA CYCLE
Phe
Tyr
Fumarate
Isocitrate
Asp
a-ketoglutarate
Succinate
Blue = Indispensable Amino Acids
Green = Conditionally Indispensable Amino Acids
Red
Succinyl CoA
CO2
= Dispensable Amino Acids
Val
Ile
Met
Thr
Arg
His
Pro
Glu
Gln