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Phosphorus-31 Magnetic Resonance Spectroscopy: A Tool for Measuring In Vivo Mitochondrial Oxidative Phosphorylation Capacity in Human Skeletal Muscle
09:40

Phosphorus-31 Magnetic Resonance Spectroscopy: A Tool for Measuring In Vivo Mitochondrial Oxidative Phosphorylation Capacity in Human Skeletal Muscle

Published on: January 19, 2017

Muscle phosphorus energy state in very-low-birth-weight infants: effect of exercise

L A Bertocci1, C E Mize, R Uauy

  • 1Rogers Magnetic Resonance Center, Department of Radiology, University of Texas Southwestern Medical Center, Dallas 75235-9085.

The American Journal of Physiology
|March 1, 1992
PubMed

Insights

Very-low-birth-weight infants exhibit skeletal muscle hypotonia due to a limited energy reserve. Phosphorus metabolite levels, measured by 31P-NMR spectroscopy, are significantly lower in these infants, indicating impaired muscle energy metabolism.

Area of Science:

  • Biochemistry
  • Neonatal Physiology
  • Skeletal Muscle Metabolism

Background:

  • Skeletal muscle hypotonia is common in very-low-birth-weight (VLBW) infants.
  • The underlying biochemical mechanisms, particularly impaired energy metabolism, are not fully understood.
  • A hypothesis suggests low skeletal muscle phosphorylation potential contributes to hypotonia.

Purpose of the Study:

  • To investigate skeletal muscle phosphorus metabolites in VLBW infants.
  • To compare energy metabolism during rest and muscle contraction between VLBW infants and controls.
  • To assess the relationship between energy state and hypotonia in VLBW infants.

Main Methods:

  • Utilized 31P-nuclear magnetic resonance (NMR) spectroscopy to measure phosphorus metabolites (phosphocreatine, inorganic phosphate, ATP, ADP).
  • Measured metabolites in skeletal muscle of VLBW infants at rest and during reflex-induced isometric contractions.
  • Compared findings with healthy larger infants and adults.

Main Results:

  • VLBW infants showed lower total phosphorus NMR signal compared to controls.
  • At rest, VLBW infants had significantly reduced ratios of phosphocreatine to total phosphorus and ATP to ADP and inorganic phosphate.
  • During contractions, these energy metabolite ratios further declined in VLBW infants, indicating limited energy reserves.

Conclusions:

  • VLBW infants possess a significantly limited skeletal muscle energy reserve.
  • Impaired high-energy phosphate metabolism contributes to hypotonia in VLBW infants.
  • 31P-NMR spectroscopy is a valuable tool for assessing muscle energy status in neonates.

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