高效液相色谱-串联质谱法检测血清油酸及其在胰岛素抵抗中的应用

目的建立高效液相色谱-串联质谱法(HPLC-MS/MS)检测血清油酸(OA),初步评估OA在2型糖尿病(T2DM)胰岛素抵抗(IR)中的作用。方法用OA-[¹³C_5]作为同位素内标物,OA和OA-[¹³C_5]的离子对分别为281.3/281.3和286.3/286.3。ZORBAX SB-Aq C18反相色谱柱,流动相A为超纯水,流动相B为甲醇乙腈(1∶1,v/v),梯度洗脱,流速0.3 mL/min。根据EP15-A3文件,考察精密度和正确度、线性范围、稳定性、携带污染率等性能以评价该方法的可靠性。选取临床确诊T2DM患者109例及体检健康者100例,用HPLC-MS/MS检测血清OA,并计算胰岛素抵抗指数(HOMA-IR)评价IR,进一步分析OA与IR的关系。结果建立的检测OA的HPLC-MS/MS特异性好,在10～1 000μmol/L范围内线性关系良好,y=0.007 55x+0.004 83,r=0.997 7,定量限(LLOQ)为10μmol/L,批内不精密度(以变异系数CV表示)≤1.62%,实验室内CV≤1.73%,方法精密度较好,适合临床血清样品的测定。与健康人对照组血清OA水平(113.20±58.00)μmol/L比较,T2DM组血清OA水平(425.58±220.17)μmol/L升高,且对照组和T2DM组OA与HOMA-IR均呈正相关。以OA诊断IR的AUC为0.689,当根据约登指数确定cut-off值为235.8μmol/L时,敏感性为70.4%,特异性为63%;当OA联合FPG诊断IR时,AUC增至0.806,且与OA诊断IR的AUC比较,差异有统计学意义(P<0.05)。结论建立了科学、高效定量检测血清OA浓度水平的HPLC-MS/MS,为动态监测代谢性疾病人群OA含量的变化提供了可靠的方法。

Establishment of high performance liquid chromatography-tandem mass spectrometry for the detection of serum oleic acid and its application in insulin resistance

Objective To establish a high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method for the detection of serum oleic acid (OA), and preliminarily evaluate the role of OA in insulin resistance (IR) of type 2 diabetes (T2DM). Methods OA-[ 13 C 5] was used as isotope-labeled internal standard, and the ion pairs of OA and OA-[ 13 C 5] were 281.3/281.3 and 286.3/286.3, respectively. The ultrapure water was used as mobile phase A and methanol: acetonitrile (1[DK(]∶[DK)]1, v/v) as mobile phase B in a ZORBAX SB-Aq C18 reversed phase column. Meanwhile, the gradient elution system with a flow rate of 0.3 mL/min was used. According to the CLSI guidelines (EP15-A3), the reliability of the established method was evaluated by detecting the performance indicators such as precision, trueness, linear range, stability and carrying contamination rate. Serum OA levels were detected by the established HPLC-MS/MS method in 109 patients with clinically diagnosed T2DM and 100 healthy controls. The insulin resistance index (HOMA-IR) was calculated to evaluate IR, and the relationship between OA and IR was further analyzed. Results The established HPLC-MS/MS method for the detection of serum OA had good specificity and linearity in the range of 10-1 000 μmol/L ( y = 0.007 55 x +0.004 83, r =0.997 7), and the low limit of quantification (LLOQ) was 10 μmol/L. It also had good precision, and the within-run coefficient of variation ( CV ) and total CV were not more than 1.62% and 1.73%, respectively, indicating that the method was suitable for the detection of serum OA. The serum OA levels in T2DM patients [(425.58 ± 220.17)μmol/L] were significantly higher than that in the healthy controls [(113.20±58.00)μmol/L], and serum OA levels were significantly correlated with HOMA-IR in T2DM patients and healthy controls. The area under the receiver operating characteristic (ROC) curve (AUC) of OA for the diagnosis of IR was 0.689. When the cut-off value identified by Youden index was 235.8 μmol/L, the sensitivity and specificity were 70.4% and 63%, respectively. When OA combined with fasting blood glucose (FBG) to diagnose IR, the AUC increased to 0.806, which was significantly higher than that of OA ( P <0.05). Conclusion A scientific and efficient HPLC-MS/MS method for the quantitative detection of serum OA is established successfully, which provides a reliable method for the dynamic monitoring of the changes of OA levels in the patients with metabolic diseases.