Phosphorous magnetic resonance spectroscopy-based skeletal muscle bioenergetic studies in subclinical hypothyroidism

J Endocrinol Invest. 2012 Feb;35(2):129-34. doi: 10.3275/7676. Epub 2011 Apr 20.

Abstract

Background: Subclinical hypothyroidism (sHT) is considered to be a milder form of thyroid dysfunction. Few earlier studies have reported neuromuscular symptoms as well as impaired muscle metabolism in sHT patients.

Aim/objective: In this study we report our findings on muscle bioenergetics in sHT patients using phosphorous magnetic resonance spectroscopy (31P MRS) and look upon the possibility to use 31P MRS technique as a clinical marker for monitoring muscle function in subclinical thyroid dysfunction.

Subjects and methods: Seventeen normal subjects, 15 patients with sHT, and 9 patients with hypothyroidism performed plantar flexion exercise while lying supine in 1.5 T magnetic resonance scanner using custom built exercise device. MR Spectroscopy measurements of inorganic phosphate (Pi), phosphocreatine (PCr), and ATP of the calf muscle were taken during rest, at the end of exercise and in the recovery phase. PCr recovery rate constant (kPCr) and oxidative capacity were calculated by monoexponential fit of PCr vs time (t) at the beginning of recovery.

Results: We observed that changes in some of the phosphometabolites (increased phosphodiester levels and Pi concentration) in sHT patients which were similar to those detected in patients with hypothyroidism. However, our results do not demonstrate impaired muscle oxidative metabolism in sHT patients based upon PCr dynamics as observed in hypothyroid patients.

Conclusions: 31P MRS-based PCr recovery rate could be used as a marker for monitoring muscle oxidative metabolism in sub clinical thyroid dysfunction.

Publication types

  • Controlled Clinical Trial

MeSH terms

  • Adult
  • Asymptomatic Diseases
  • Energy Metabolism* / physiology
  • Exercise / physiology
  • Female
  • Humans
  • Hypothyroidism / diagnosis
  • Hypothyroidism / metabolism*
  • Magnetic Resonance Spectroscopy / methods*
  • Male
  • Middle Aged
  • Muscle, Skeletal / chemistry
  • Muscle, Skeletal / metabolism*
  • Phosphocreatine / analysis
  • Phosphocreatine / metabolism
  • Phosphorus / analysis
  • Recovery of Function / physiology
  • Rest / physiology
  • Young Adult

Substances

  • Phosphocreatine
  • Phosphorus