Elevated Serum Creatine Phosphokinase in Choline-Deficient Humans: Mechanistic Studies in C2C12 Mouse Myoblasts

Am J Clin Nutr. 2004 Jul;80(1):163-70. doi: 10.1093/ajcn/80.1.163.

Abstract

Background: Choline is a required nutrient, and humans deprived of choline develop liver damage.

Objective: This study examined the effect of choline deficiency on muscle cells and the release of creatine phosphokinase (CPK) as a sequela of that deficiency.

Design: Four men were fed diets containing adequate and deficient amounts of choline, and serum was collected at intervals for measurement of CPK. C2C12 mouse myoblasts were cultured in a defined medium containing 0 or 70 micromol choline/L for up to 96 h, and CPK was measured in the media; choline and metabolites were measured in cells. Apoptosis was assessed by using terminal deoxynucleotidyl transferase-mediated dUTP-biotin end labeling and activated caspase-3 immunohistochemistry. Cell fragility in response to hypo-osmotic stress was also assessed.

Results: Three of 4 humans fed a choline-deficient diet had significantly elevated serum CPK activity derived from skeletal muscle (up to 66-fold; P < 0.01) that resolved when choline was restored to their diets. Cells grown in choline-deficient medium for 72 h leaked 3.5-fold more CPK than did cells grown in medium with 70 micromol choline/L (control medium; P < 0.01). Apoptosis was induced in cells grown in choline-deficient medium. Phosphatidylcholine concentrations were diminished in choline-deficient cells (to 43% of concentrations in control cells at 72 h; P < 0.01), as were concentrations of intracellular choline, phosphocholine, and glycerophosphocholine. Cells grown in choline-deficient medium had greater membrane osmotic fragility than did cells grown in control medium.

Conclusions: Choline deficiency results in diminished concentrations of membrane phosphatidylcholine in myocytes, which makes them more fragile and results in increased leakage of CPK from cells. Serum CPK may be a useful clinical marker for choline deficiency in humans.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adult
  • Animals
  • Apoptosis / drug effects
  • Biomarkers / blood
  • Caspase 3
  • Caspases / metabolism
  • Cell Line
  • Choline Deficiency / enzymology*
  • Creatine Kinase / blood*
  • Creatine Kinase / metabolism
  • Culture Media
  • DNA Fragmentation
  • Humans
  • Immunohistochemistry
  • In Situ Nick-End Labeling
  • Liver / pathology
  • Male
  • Mice
  • Middle Aged
  • Myoblasts, Skeletal / enzymology*
  • Myoblasts, Skeletal / metabolism
  • Osmotic Fragility

Substances

  • Biomarkers
  • Culture Media
  • Creatine Kinase
  • CASP3 protein, human
  • Casp3 protein, mouse
  • Caspase 3
  • Caspases