In vitro probe acylcarnitine profiling assay using cultured fibroblasts and electrospray ionization tandem mass spectrometry predicts severity of patients with glutaric aciduria type 2.
Glutaric aciduria type 2 (multiple acyl-CoA dehydrogenase deficiency, MAD) is a multiple defect of mitochondrial acyl-CoA dehydrogenases due to a deficiency of electron transfer flavoprotein (ETF) or ETF dehydrogenase. The clinical spectrum are relatively wide from the neonatal onset, severe form (MAD-S) to the late-onset, milder form (MAD-M). In the present study, we determined whether the in vitro probe acylcarnitine assay using cultured fibroblasts and electrospray ionization tandem mass spectrometry (MS/MS) can evaluate their clinical severity or not. Incubation of cells from MAD-S patients with palmitic acid showed large increase in palmitoylcarnitine (C16), whereas the downstream acylcarnitines; C14, C12, C10 or C8 as well as C2, were extremely low. In contrast, accumulation of C16 was smaller while the amount of downstream metabolites was higher in fibroblasts from MAD-M compared to MAD-S. The ratio of C16/C14, C16/C12, or C16/C10, in the culture medium was significantly higher in MAD-S compared with that in MAD-M. Loading octanoic acid or myristic acid led to a significant elevation in C8 or C12, respectively in MAD-S, while their effects were less pronounced in MAD-M. In conclusion, it is possible to distinguish MAD-S and MAD-M by in vitro probe acylcarnitine profiling assay with various fatty acids as substrates. This strategy may be applicable for other metabolic disorders.
Endo
Mitsuru
M
Department of Pediatrics, Shimane University School of Medicine, 89-1 En-ya, Izumo, Shimane 693-8501, Japan.
Hasegawa
Yuki
Y
Fukuda
Seiji
S
Kobayashi
Hironori
H
Yotsumoto
Yuka
Y
Mushimoto
Yuichi
Y
Li
Hong
H
Purevsuren
Jamiyan
J
Yamaguchi
Seiji
S
D002331:Carnitine / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism; D016022:Case-Control Studies; D002478:Cells, Cultured; D005347:Fibroblasts / Q000737:chemistry* / Q000378:metabolism; D006801:Humans; D015394:Molecular Structure; D054069:Multiple Acyl Coenzyme A Dehydrogenase Deficiency / Q000378:metabolism*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*
C116917:acylcarnitine; D002331:Carnitine