Clinical applications of 3-hydroxy fatty acid analysis by gas chromatography-mass spectrometry

Patricia M. Jones, Michael J. Bennett

Research output: Contribution to journalReview articlepeer-review

16 Scopus citations

Abstract

Background: L-3-Hydroxy fatty acids are unusual metabolites and rarely occur in significant quantities in normal human physiology. Genetic defects of both long-chain and medium-/short-chain mitochondrial L-3 hydroxyacyl coenzyme A dehydrogenases (LCHAD, M/SCHAD) have been identified as significant metabolic diseases in humans often with severe clinical phenotypes and pathophysiology that appears to differ from other defects of straight chain fatty acid oxidation. It is felt that accumulation of these atypical fatty acid species may play a role in this pathology. We have therefore developed an assay to measure these compounds in body fluids, and tissue culture medium to help in the diagnosis of these disorders and to better study the effects of 3-hydroxy fatty acid accumulation. Methods: We have developed a stable isotope dilution, selected ion-monitoring gas chromatography-mass spectrometric assay for the measurement of all 3-hydroxy fatty acids from chain lengths C6 to C18 using 1,2 13C-labeled internal standards for all species. Authentic patient samples were utilized to develop reference intervals for control subjects, for those associated with patient samples confirmed at the molecular level to have either LCHAD or M/SCHAD deficiency and for patients who did not have disease but were fasting or on diets high in medium-chain fatty acids. Likewise, skin fibroblasts were obtained from patients with confirmed disease for additional study. Samples were also obtained from the hadh (M/SCHAD) knockout mouse. Results: The measurement of 3-hydroxy fatty acids in patient plasma is a valuable tool in the identification of defects of both enzymes. Severe starvation, prolonged fasting and increased medium-chain triglycerides in the diet produce a profile that is similar to that seen in M/SCHAD deficiency, making this a more difficult condition to diagnose but these biomarkers provide an important clue to the diagnosis, particularly in non-fasted, diet-controlled patients. Fibroblast studies in LCHAD deficiency demonstrate that long-chain 3-hydroxy fatty acid accumulation can be observed in cultured tissues. Incubation of cultured fibroblasts from LCHAD deficient patients with labeled fatty acids demonstrated a process of chain lengthening that has not previously been recognized. Conclusions: The measurement of body fluid and cultured cell 3-hydroxy fatty acids provides both diagnostic and pathogenic information regarding these genetic diseases of fatty acid oxidation in the mitochondrion. Presently, the measurement of medium- and short-chain species provides a major metabolic biomarker for the recognition of M/SCHAD deficiency. This article is part of a Special Issue entitled Lipodomics and Imaging Mass Spectrometry.

Original languageEnglish (US)
Pages (from-to)657-662
Number of pages6
JournalBiochimica et Biophysica Acta - Molecular and Cell Biology of Lipids
Volume1811
Issue number11
DOIs
StatePublished - Nov 1 2011

Keywords

  • 3-hydroxy fatty acids
  • Fatty acid oxidation
  • Long-chain 3-hydroxyacyl-CoA dehydrogenase deficiency
  • Medium and short-chain 3-hydroxyacyl-CoA dehydrogenase deficiency
  • Medium-chain triglycerides

ASJC Scopus subject areas

  • Molecular Biology
  • Cell Biology

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