Development of a Diagnostic Screening Strategy for Niemann–Pick Diseases Based on Simultaneous Liquid Chromatography-Tandem Mass Spectrometry Analyses of N-Palmitoyl-O-phosphocholine-serine and Sphingosylphosphorylcholine

• Published in: Biological & pharmaceutical bulletin 2020/09/01, Vol.43(9), pp.1398-1406
• Main Authors: Iwahori, Anna, Maekawa, Masamitsu, Narita, Aya, Kato, Akie, Sato, Toshihiro, Ogura, Jiro, Sato, Yu, Kikuchi, Masafumi, Noguchi, Atsuko, Higaki, Katsumi, Okuyama, Torayuki, Takahashi, Tsutomu, Eto, Yoshikatsu, Mano, Nariyasu
• Format: Article
• Language: English
• Subjects: Brain diseases; Chromatography; discrimination; Genetic disorders; Liquid chromatography; liquid chromatography-tandem mass spectrometry (LC-MS/MS); Mass spectrometry; Mass spectroscopy; Metabolic disorders; Methods; N-palmitoyl-O-phosphocholine-serine; Niemann–Pick disease; Phosphocholine; Scientific imaging; screening; Serine; sphingosylphosphocholine; Sphingosylphosphorylcholine
• ISSN: 0918-6158; 1347-5215
• DOI: 10.1248/bpb.b20-00400

Early diagnosis of Niemann–Pick diseases (NPDs) is important for better prognosis of such diseases. N-Palmitoyl-O-phosphocholine-serine (PPCS) is a new NPD biomarker possessing high sensitivity, and with its combination with sphingosylphosphocholine (SPC) it may be possible to distinguish NPD-C from NPD-A/B. In this study, a rapid liquid chromatography-tandem mass spectrometry (LC-MS/MS) method (method 1) and a validated LC-MS/MS analysis (method 2) of PPCS and SPC were developed, and we have proposed a diagnostic screening strategy for NPDs using a combination of serum PPCS and SPC concentrations. Nexera and API 5000 were used as LC-MS/MS systems. C18 columns with lengths of 10 and 50 mm were used for method 1 and 2, respectively. 2H3-Labeled PPCS and nor-SPC were used as internal standards. Selective reaction monitoring in positive-ion mode was used for MS/MS. Run times of 1.2 and 8 min were set for methods 1 and 2, respectively. In both methods 1 and 2, two analytes showed high linearity in the range of 1–4000 ng/mL. Method 2 provided high accuracy and precision in method validation. Serum concentrations of both analytes were significantly higher in NPD-C patients than those of healthy subjects in both methods. Serum PPCS correlated between methods 1 and 2; however, it was different in the case of SPC. The serum PPCS/SPC ratio was different in healthy subjects, NPD-C, and NPD-A/B. These results suggest that using a combination of the two LC-MS/MS analytical methods for PPCS and SPC is useful for diagnostic screening of NPDs.