Maekawa Masamitsu, Shimada Miki, Ohno Kousaku, Togawa Masami, Nittono Hiroshi, Iida Takashi, Hofmann Alan F, Goto Junichi, Yamaguchi Hiroaki, Mano Nariyasu
Department of Pharmaceutical Sciences, Tohoku University Hospital, Sendai, Japan.
Faculty of Medicine, Tottori University, Tottori, Japan.
Ann Clin Biochem. 2015 Sep;52(Pt 5):576-87. doi: 10.1177/0004563214568871. Epub 2015 Jan 9.
Various conjugated cholesterol metabolites are excreted in urine of the patients with metabolic abnormalities and hepatobiliary diseases. We aimed to examine the usefulness of precursor ion scan and neutral loss scan for the characterization of conjugated cholesterol metabolites in urine.
A mixture of authentic standards of conjugated cholesterol metabolites was used for investigating the performance of the present method. The urine of patients with Niemann-Pick diseases type C and 3β-hydroxysteroid dehydrogenase deficiency were analysed by precursor ion scan of m/z 97, 74, and 124.
A precursor ion scan of m/z 97 was effective for identifying conjugates with ester sulphates on hydroxyl groups whereas ester sulphates on phenolic alcohols were signalled by a neutral loss scan of 80 Da. Monosaccharide-conjugated cholesterol metabolites were signalled by a precursor ion scan of m/z 113. Although precursor ion scan of m/z 74 and 124 was effective for finding glycine- and taurine-conjugated metabolites, high intensity of product ions (m/z 74 and 124) disturbed measurement of other multiply conjugated metabolites. The urine samples contained many conjugated cholesterol metabolites, and there were several disease-specific intense peaks. We found several unknown intense peaks with three known peaks in urine of the Niemann-Pick type C patient. In the patient with 3β-hydroxysteroid dehydrogenase deficiency, intense peaks that were tentatively identified as 5-cholenoic acid sulphates and their glycine and taurine conjugates were present.
The method should lead to the discovery of new urinary biomarkers for these disturbances of cholesterol catabolism and transport.
各种共轭胆固醇代谢产物在代谢异常和肝胆疾病患者的尿液中排泄。我们旨在研究前体离子扫描和中性丢失扫描在尿液中共轭胆固醇代谢产物表征方面的实用性。
使用共轭胆固醇代谢产物的真实标准品混合物来研究本方法的性能。通过对质荷比为97、74和124的前体离子扫描分析尼曼-匹克病C型和3β-羟基类固醇脱氢酶缺乏症患者的尿液。
质荷比为97的前体离子扫描对于鉴定羟基上带有硫酸酯的共轭物有效，而酚醇上的硫酸酯通过80 Da的中性丢失扫描来信号化。单糖共轭胆固醇代谢产物通过质荷比为113的前体离子扫描来信号化。尽管质荷比为74和124的前体离子扫描对于发现甘氨酸和牛磺酸共轭代谢产物有效，但产物离子（质荷比为74和124）的高强度干扰了其他多重共轭代谢产物的测量。尿液样本中含有许多共轭胆固醇代谢产物，并且有几个疾病特异性的强峰。我们在尼曼-匹克C型患者的尿液中发现了几个未知的强峰以及三个已知峰。在3β-羟基类固醇脱氢酶缺乏症患者中，存在暂时鉴定为5-胆烯酸硫酸盐及其甘氨酸和牛磺酸共轭物的强峰。
该方法应有助于发现这些胆固醇分解代谢和转运紊乱的新尿液生物标志物。
