Accumulation of free 3-hydroxy fatty acids in the culture media of fibroblasts from patients deficient in long-chain L-3-hydroxyacyl-CoA dehydrogenase: A useful diagnostic aid
Pm. Jones et al., Accumulation of free 3-hydroxy fatty acids in the culture media of fibroblasts from patients deficient in long-chain L-3-hydroxyacyl-CoA dehydrogenase: A useful diagnostic aid, CLIN CHEM, 47(7), 2001, pp. 1190-1194
Background: The diagnosis of long-chain L-3-hydroxyacyl-coenzyme A dehydrog
enase (LCHAD) deficiency frequently requires the study of cultured fibrobla
sts. We developed such a test that does not require disruption and loss of
the cells.
Methods: We measured free 8-hydroxy fatty acids (3-OHFAs) in media of skin
fibroblasts cultures from 11 patients with a genetic deficiency of LCHAD an
d the associated disorder of mitochondrial trifunctional protein (MTFP). Fi
broblasts were cultured for 24 h with 100 mu mol/L nonisotopic palmitate ad
ded. 3-OHFAs were measured by selected-ion monitoring, stable-isotope dilut
ion gas chromatography-mass spectrometry with [C-13]-labeled internal stand
ards.
Results: 3-OH-hexadecanoic and 9-OH-tetradecanoic FAs were increased 14- an
d 11-fold, respectively, in all patients with LCHAD or MTFP deficiency when
compared with control fibroblast cell lines after overnight incubation wit
h palmitate. 3-OH-dodecanoic FA demonstrated a modest, fivefold increase in
LCHAD-deficient cells. The concentrations of all 3-OHFAs were similar whet
her or not the medium samples were hydrolyzed to release conjugated species
such as acylcarnitines, suggesting that 3-OHFAs accumulate in the media as
free FAs.
Conclusions: Measurement of 3-OHFA excretion from LCHAD- or MTFP-deficient
cell lines can be used as a diagnostic tool. Free FAs are the predominant f
orm of these abnormal metabolic intermediates in culture media. (C) 2001 Am
erican Association for Clinical Chemistry.