Ćwiklińska Agnieszka, Mickiewicz Agnieszka, Kowalski Robert, Kortas-Stempak Barbara, Kuchta Agnieszka, Mucha Krzysztof, Makowiecki Michał, Gliwińska Anna, Lewandowski Krzysztof, Pączek Leszek, Fijałkowski Marcin, Gruchała Marcin, Jankowski Maciej
Medical University of Gdansk, Department of Clinical Chemistry, Gdansk, Poland.
Medical University of Gdansk, 1st Department of Cardiology, Gdansk, Poland.
J Med Biochem. 2020 Sep 2;39(3):283-289. doi: 10.2478/jomb-2019-0038.
Lipoprotein X (LpX) is an abnormal lipoprotein fraction, which can be detected in patients with severe hypercholesterolaemia and cholestatic liver disease. LpX is composed largely of phospholipid and free cholesterol, with small amounts of triglyceride, cholesteryl ester and protein. There are no widely available methods for direct measurement of LpX in routine laboratory practice. We present the heterogeneity of clinical and laboratory manifestations of the presence of LpX, a phenomenon which hinders LpX detection.
The study was conducted on a 26-year-old female after liver transplantation (LTx) with severely elevated total cholesterol (TC) of 38 mmol/L and increased cholestatic liver enzymes. TC, free cholesterol (FC), cholesteryl esters (CE), triglycerides, phospholipids, HDL-C, LDL-C, and apolipoproteins AI and B were measured. TC/apoB and FC:CE ratios were calculated. Lipoprotein electrophoresis was performed using a commercially available kit and laboratory-prepared agarose gel.
Commercially available electrophoresis failed to demonstrate the presence of LpX. Laboratory-prepared gel clearly revealed the presence of lipoproteins with γ mobility, characteristic of LpX. The TC/apoB ratio was elevated and the CE level was reduced, confirming the presence of LpX. Regular lipoprotein apheresis was applied as the method of choice in LpX disease and a bridge to reLTx due to chronic liver insufficiency.
The detection of LpX is crucial as it may influence the method of treatment. As routinely available biochemical laboratory tests do not always indicate the presence of LpX, in severe hypercholesterolaemia with cholestasis, any discrepancy between electrophoresis and biochemical tests should raise suspicions of LpX disease.
脂蛋白X（LpX）是一种异常脂蛋白组分，可在严重高胆固醇血症和胆汁淤积性肝病患者中检测到。LpX主要由磷脂和游离胆固醇组成，含有少量甘油三酯、胆固醇酯和蛋白质。在常规实验室实践中，尚无广泛可用的直接测量LpX的方法。我们展示了LpX存在时临床和实验室表现的异质性，这一现象阻碍了LpX的检测。
对一名26岁肝移植后女性进行研究，其总胆固醇（TC）严重升高至38 mmol/L，胆汁淤积性肝酶升高。检测了TC、游离胆固醇（FC）、胆固醇酯（CE）、甘油三酯、磷脂、高密度脂蛋白胆固醇（HDL-C）、低密度脂蛋白胆固醇（LDL-C）以及载脂蛋白AI和B。计算了TC/载脂蛋白B和FC:CE比值。使用市售试剂盒和实验室制备的琼脂糖凝胶进行脂蛋白电泳。
市售电泳未能显示LpX的存在。实验室制备的凝胶清楚地显示出具有LpX特征的γ迁移率脂蛋白的存在。TC/载脂蛋白B比值升高，CE水平降低，证实了LpX的存在。常规脂蛋白分离术被用作LpX疾病的首选治疗方法以及因慢性肝功能不全而进行再次肝移植的桥梁。
LpX的检测至关重要，因为它可能影响治疗方法。由于常规可用的生化实验室检测并不总是能表明LpX的存在，在伴有胆汁淤积的严重高胆固醇血症中，电泳和生化检测之间的任何差异都应引起对LpX疾病的怀疑。
