Aston Research Centre for Healthy Ageing, School of Life and Health Sciences, Aston University, Birmingham B4 7ET, UK.
Institute of Cardiovascular Sciences, University of Birmingham, Birmingham, UK.
Redox Biol. 2018 Jun;16:139-145. doi: 10.1016/j.redox.2018.02.014. Epub 2018 Feb 17.
Oxysterols (OHC) are biologically active cholesterol metabolites circulating in plasma that may be formed enzymatically (e.g. 24S-OHC, 25-OHC and 27-OHC) or by autoxidative mechanisms (e.g. 7-ketocholesterol, 7β-OHC and 25-OHC). Oxysterols are more soluble than cholesterol and are reported to exert inflammatory, cytoprotective and apoptotic effects according to concentration and species. Esterified oxysterols have been analysed in people with dementia and cardiovascular diseases although there is no consistent relationship between oxysterol esters and disease. However, oxysterol esters are held in lipoprotein core and may not relate to the concentration and activity of plasma free oxysterols. Methodological limitations have challenged the analysis of free oxysterols to date. We have developed a fast, sensitive and specific quantitative LC-MS/MS, multiple reaction monitoring (MRM) method to target five oxysterols in human plasma with analyte recoveries between 72% and 82% and sensitivities between 5 and 135 pg/ml. A novel method was used to investigate the hypothesis that simvastatin may reduce the concentrations of specific plasma free oxysterols in hypercholesterolaemia. Twenty healthy male volunteers were recruited (aged 41-63 years); ten were asymptomatic with high plasma cholesterol > 6.5 mM and ten were healthy with normal plasma cholesterol (< 6.5 mM). Simvastatin (40 mg/day) was prescribed to those with hypercholesterolaemia. Plasma samples were taken from both groups at baseline and after three months. Simvastatin reduced plasma cholesterol by ~35% (p < 0.05) at the end of three months. Oxysterols generated by autoxidation (but not enzymatically) were elevated up to 45 fold in hypercholesterolaemic midlife men. Plasma oxysterols were restored to those of healthy controls after simvastatin intervention suggesting that autoxidation is either prevented by simvastatin directly or that autoxidation is less prevalent when plasma cholesterol concentrations are within the normal range.
氧化固醇（OHC）是循环在血浆中的生物活性胆固醇代谢物，可能通过酶促途径（例如 24S-OHC、25-OHC 和 27-OHC）或自动氧化机制（例如 7-酮胆固醇、7β-OHC 和 25-OHC）形成。氧化固醇比胆固醇更具水溶性，据报道，其浓度和种类不同，具有炎症、细胞保护和细胞凋亡作用。尽管氧化固醇酯与疾病之间没有一致的关系，但已在痴呆症和心血管疾病患者中分析了酯化氧化固醇。然而，氧化固醇酯存在于脂蛋白核心中，可能与血浆游离氧化固醇的浓度和活性无关。迄今为止，分析游离氧化固醇的方法学限制了其发展。我们已经开发了一种快速、灵敏和特异的 LC-MS/MS 定量方法，多重反应监测（MRM），以靶向人血浆中的五种氧化固醇，分析物回收率在 72%至 82%之间，灵敏度在 5 至 135pg/ml 之间。采用一种新方法来研究辛伐他汀是否可能降低高胆固醇血症患者特定血浆游离氧化固醇浓度的假设。招募了 20 名健康男性志愿者（年龄 41-63 岁）；其中 10 名无症状者血浆胆固醇水平较高（>6.5mmol/L），10 名健康者血浆胆固醇水平正常（<6.5mmol/L）。高胆固醇血症患者服用辛伐他汀（40mg/天）。两组患者均在基线和三个月后采集血浆样本。三个月后，辛伐他汀将血浆胆固醇降低了约 35%（p<0.05）。由自动氧化产生的氧化固醇（而非酶促途径）在中年高胆固醇血症男性中升高了 45 倍。辛伐他汀干预后，血浆氧化固醇恢复至健康对照组水平，提示辛伐他汀直接阻止了自动氧化，或者当血浆胆固醇浓度处于正常范围时，自动氧化的发生率较低。
