背景:谷甾醇血症是一种罕见的遗传性脂质代谢紊乱,其特征是植物甾醇水平升高和动脉粥样硬化加速。尽管早期发现有利于预防疾病进展,基于常规血脂谱的常规筛查在很大程度上诊断不足.
方法:已经开发并验证了基于气相色谱-质谱(GC-MS)的图谱,以测量生物活性游离甾醇的水平,包括五种内源甾醇和三种植物甾醇(谷甾醇,菜油甾醇,和豆甾醇)在干血斑(DBS)中。
结果:运行中和运行间精度分别为1.4-11.1%和2.2-14.1%,分别,而所有甾醇的准确度均为86.3~121.9%,相关系数(r2)>0.988。在患者中(四个女孩和两个男孩,6.5±2.8年),谷甾醇水平显著升高,最佳临界值为2.5µg/mL,将其与93名年龄匹配的健康儿童区分开来。将患者与六个ABCG5/ABCG8杂合子携带者区分为31.9的临界值。此外,谷甾醇与胆固醇的分子比,地莫甾醇,和7-脱氢胆固醇分别提供了26.3、67.6和21.6的优异截止值,将患者与健康对照和杂合携带者区分开来。
结论:基于新型DBS的游离甾醇GC-MS分析可准确识别出谷甾醇血症患者,具有与血清测定相当的性能。DBS分析在临床实践和人群筛查计划中可能是更可行的方法,它可以为单个植物甾醇提供诊断临界值。
BACKGROUND: Sitosterolemia is a rare inherited lipid metabolic disorder characterized by increased levels of plant sterols and accelerated atherosclerosis. Although early detection is beneficial for the prevention of disease progression, it is largely underdiagnosed by routine screening based on conventional lipid profiles.
METHODS: A gas chromatography-mass spectrometry (GC-MS)-based profiling has been developed and validated to measure the levels of biologically active free sterols, including five endogenous sterols and three plant sterols (sitosterol, campesterol, and stigmasterol) in dried blood spot (DBS).
RESULTS: Within- and between-run precisions were 1.4-11.1 % and 2.2-14.1 %, respectively, while the accuracies were all 86.3 ∼ 121.9 % with the correlation coefficients (r2) > 0.988 for all the sterols. In the patients (four girls and two boys, 6.5 ± 2.8 years), sitosterol levels were significantly increased, with an optimal cut-off value of 2.5 µg/mL distinguishing them from ninety-three age-matched healthy children. A cut-off value of 31.9 µg/mL differentiated the patients from six ABCG5/ABCG8 heterozygous carriers. In addition, the molecular ratios of sitosterol to cholesterol, desmosterol, and 7-dehydrocholesterol provided excellent cut-off values of 26.3, 67.6, and 21.6, respectively, to distinguish patients from both healthy controls and heterozygous carriers.
CONCLUSIONS: The novel DBS-based GC-MS profiling of free sterols accurately identified patients with sitosterolemia, with a performance comparable to that of a serum assay. The DBS profiling could be more feasible method in clinical practice as well as population screening programs, and it can provide diagnostic cut-off values for individual plant sterols.