Intramuscular short-chain acylcarnitines in elderly people are decreased in (pre-)frail females, but not in males

FASEB J. 2020 Sep;34(9):11658-11671. doi: 10.1096/fj.202000493R. Epub 2020 Jul 16.

Abstract

This study tested the hypothesis that in human aging, a decreased intramuscular acylcarnitine status is associated with (pre-)frailty, reduced physical performance, and altered mitochondrial function. We used a cross-sectional study design with well-matched fit and (pre-)frail old males and females, using young males and females as healthy controls. Frailty was assessed according to the Fried criteria and physical performance was determined by 400 m walk test, short physical performance battery and handgrip strength. Muscle and plasma acylcarnitine status, and muscle mitochondrial gene expression was analyzed. Results showed that intramuscular total carnitine levels and short-chain acylcarnitine levels were lower in (pre-)frail old females compared to fit old females and young females, whereas no differences were observed in males. The low intramuscular short-chain acylcarnitine levels in females correlated with low physical performance, even after correction for muscle mass (%), and were accompanied with lowered expression of genes involved in mitochondrial energy production and functionality. It is, therefore, concluded that in (pre-)frail old females, intramuscular total carnitine levels and short-chain acylcarnitine levels are decreased, and this decrease is associated with reduced physical performance and low expression of a wide range of genes critical for mitochondrial function. The results stress the importance of taking sex differences into account in aging research.

Keywords: acetylcarnitine; carnitine; frailty; mitochondrial dysfunction; mitochondrial energy production; physical function.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Aged, 80 and over
  • Aging / metabolism
  • Aging / physiology*
  • Carnitine / analogs & derivatives*
  • Carnitine / blood
  • Carnitine / chemistry
  • Carnitine / metabolism
  • Cross-Sectional Studies
  • Female
  • Frail Elderly
  • Frailty / metabolism
  • Frailty / physiopathology*
  • Hand Strength / physiology*
  • Humans
  • Male
  • Muscles / metabolism*
  • Physical Fitness / physiology*
  • Sex Factors
  • Walking / physiology

Substances

  • acylcarnitine
  • Carnitine