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EP-4741813-A1 - ANALYSIS METHOD USING LYSOPHOSPHATIDYLCHOLINE COMPOUND CONTAINING STABLE ISOTOPE ELEMENT IN CHOLINE MOIETY

EP4741813A1EP 4741813 A1EP4741813 A1EP 4741813A1EP-4741813-A1

Abstract

A technology capable of analyzing lysophosphatidylcholine and lysophosphatidic acid in cerebrospinal fluid with high accuracy can be developed by a method, which is an analytical method including a step of detecting at least one of lysophosphatidylcholine and lysophosphatidic acid in a biological sample by mass spectrometry, wherein a lysophosphatidylcholine compound containing a stable isotope element in the choline moiety is used as a standard sample.

Inventors

  • FUJIMURA, Daiki
  • YAMAKI, SATOSHI
  • YAMADA, MASAKI
  • MATSUMOTO, KEIKO

Assignees

  • SHIMADZU CORPORATION

Dates

Publication Date
20260513
Application Date
20240501

Claims (6)

  1. An analytical method comprising a step of detecting at least one of lysophosphatidylcholine and lysophosphatidic acid in a biological sample by mass spectrometry, wherein a lysophosphatidylcholine compound containing a stable isotope element in the choline moiety is used as a standard sample.
  2. The method according to claim 1, wherein the stable isotope element is at least one of deuterium and heavy carbon.
  3. The method according to claim 1 or 2, wherein the lysophosphatidylcholine compound containing a stable isotope element in the choline moiety is LPC_18_0 or LPC_18_1 containing a stable isotope element in the choline moiety.
  4. The method according to claim 3, wherein the lysophosphatidylcholine compound containing a stable isotope element in the choline moiety has the following structure:
  5. The method according to claim 1, wherein lysophosphatidylcholine in the biological sample is detected.
  6. The method according to claim 1, wherein the biological sample is cerebrospinal fluid.

Description

TECHNICAL FIELD The present invention relates to an analytical method using a lysophosphatidylcholine compound containing a stable isotope element in the choline moiety. BACKGROUND ART As a method for objectively evaluating pain, which is a subjective measure, for example, Japanese Unexamined Patent Application Publication No. 2017-187492 proposes a method for detecting at least one of lysophosphatidylcholine (LPC) and lysophosphatidic acid (LPA) in a sample derived from human cerebrospinal fluid. In this method, specific examples of lysophosphatidylcholine include one or more selected from LPC_14_0, LPC_16_0, LPC_16_1, LPC_18_0, LPC_18_1, LPC_18_2, LPC_20_4, LPC_20_5, and LPC_22_6, and specific examples of lysophosphatidic acid include one or more selected from total LPA, LPA_16_0, LPA_18_0, LPA_18_1, LPA_18_2, LPA_20_4, and LPA_22_6. Here, in the specific examples of LPC and LPA, the first number indicates the number of carbon atoms in the fatty acid chain, and the second number indicates the number of double bonds in the fatty acid chain. Conventionally, when detecting lysophosphatidylcholine and lysophosphatidic acid by mass spectrometry (MS), LPA_17_0 (stable isotope is unlabeled) represented by the following structure, which is not present in biological samples, has been used as a standard sample. However, in recent years, it has been found that LPA_17_0 may be slightly contained depending on the person, and even when quantification is performed using LPA_17_0 as a standard sample, there has been a problem with its accuracy. To solve this problem, for example, it has been proposed to use a lysophosphatidylcholine compound (18:1-d7 Lyso PC / C26H45D7NO7P) represented by the following structure, into which a stable isotope element has been introduced, as a standard sample. However, as shown in FIG. 2, this lysophosphatidylcholine compound is ionized at the moiety adjacent to the phosphate group during MS analysis, generating a product ion of m/z = 184. This product ion has the same mass as the product ion of LPC, and their retention times are close. Therefore, if the product ion to be selected is set to m/z = 184, crosstalk (a phenomenon in which ions stagnate in the collision cell, and the product ion of the measurement component is erroneously detected) occurs, and an improvement in quantitative accuracy has been demanded. PRIOR ART DOCUMENTS PATENT DOCUMENTS Patent Document 1: Japanese Unexamined Patent Application Publication No. 2017-187492 SUMMARY OF INVENTION PROBLEM TO BE SOLVED BY THE INVENTION An object of the present invention is to solve the above problems and to develop a technology capable of analyzing lysophosphatidylcholine and lysophosphatidic acid in cerebrospinal fluid with high accuracy. MEANS FOR SOLVING THE PROBLEM A first aspect of the present invention relates to an analytical method including a step of detecting at least one of lysophosphatidylcholine and lysophosphatidic acid in a biological sample by mass spectrometry, wherein a lysophosphatidylcholine compound containing a stable isotope element in the choline moiety is used as a standard sample. EFFECTS OF INVENTION According to the analytical method of the present invention, quantitative accuracy can be improved by using a compound that does not exist in vivo as a standard sample. Furthermore, according to the analytical method of the present invention, by using a lysophosphatidylcholine compound containing a stable isotope element in the choline moiety as a standard sample, contamination to the detection target and crosstalk in mass spectrometry can be avoided, and quantitative accuracy can be improved. BRIEF DESCRIPTION OF DRAWINGS [FIG. 1] FIG. 1 is a diagram showing a particularly preferable example of a lysophosphatidylcholine compound used as a labeled sample in the first aspect of the present invention.[FIG. 2] FIG. 2 is a diagram showing a conventional lysophosphatidylcholine compound into which a stable isotope element has been introduced. DESCRIPTION OF EMBODIMENTS A first aspect of the present invention is an analytical method including a step of detecting at least one of lysophosphatidylcholine and lysophosphatidic acid in a biological sample by mass spectrometry, wherein a lysophosphatidylcholine compound containing a stable isotope element in the choline moiety is used as a standard sample. In the first aspect of the present invention, quantitative accuracy can be improved by using a lysophosphatidylcholine compound containing a stable isotope element that does not exist in vivo as a standard sample. However, where the stable isotope element is contained in the lysophosphatidylcholine compound may cause a large difference in quantitative accuracy. In the first aspect of the present invention, by introducing a stable isotope element into the choline moiety adjacent to the phosphate group of lysophosphatidylcholine for labeling, contamination to the detection target and crosstalk in mass spectrometry can be avoi