高效液相色谱-荧光检测法在慢性肾功能不全患者血清芳香族氨基酸检测中的临床价值

目的 建立同时测定血清AAA含量的HPLC-FLD法，探讨CRI患者血清AAA含量变化及其临床应用价值。方法血清标本来自于100名健康体检者和80例CRI患者。将CRI患者按2002年美国肾脏基金会(NKF)诊断分期标准进行分期：CKD 2期4例、CKD 3期12例、CKD 4期12例和CKD 5期52例；按CRI不同病因分组：慢性肾炎型32例、糖尿病型36例和高血压型12例。血清经高氯酸去蛋白后，离心取上清液测定，外标法定量。采用Megres C18色谱柱，流动相为乙腈：水（体积比为1∶9），流速为1.0 ml/min,荧光检测器在不同时间段设定特定波长对血清AAA进行测定。对健康对照组和CRI患者组血清中AAA总量、Tyr、Phe和Trp含量及不同分期和不同病因CRI患者血清Tyr、Phe和Trp含量进行比较，同时评价血清AAA总量诊断CRI的敏感度与特异度。结果Tyr、Phe和Trp线性范围分别为0.550～275.000、3.050 ～1 220.000和0.049～49.000 μmol/L，最低检测限分别为0.014、0.500和0.005 μmol/L,平均回收率分别为100.9％、101.3％和98.5％，日内精密度为2.32％～3.92％（平均为3.13％），日间精密度为3.18％ ～4.20％（平均为3.58％）。CRI患者组血清AAA总量、Tyr、Trp含量及Tyr/Phe比值分别为(135.74±12.23)、(52.27±8.25)、(21.49±4.25) μmoL/L和0.87（0.68 ～1.05）]，低于健康对照组的(174.47±11.57)、（63.53±4.68）、(44.22±3.67) μmol/L和0.97（0.94～1.00）]，差异均有统计学意义（t=- 14.709、4.452、22.100,U=266.000,P均＜0.05）。不同分期CRI患者Tyr、Phe和Trp含量差异无统计学意义；Tyr含量在慢性肾炎组、高血压组和糖尿病组间差异无统计学意义，Phe在慢性肾炎组与高血压组、慢性肾炎组与糖尿病组间差异有统计学意义（U= 114.00、395.00，P均＜0.05），Trp在慢性肾炎组与糖尿病组间差异有统计学意义(U=349.00,P＜0.05)。血清AAA总量诊断CRI的敏感度、特异度分别为90％ (72/80)和100％ (100/100)。结论HPLC-FLD法测定血清AAA简便、快速，敏感度高及特异度好，同时测定血清AAA含量对CRI患者的诊断和评价有一定价值。

Determination of serum aromatic amino acid in patients with CRI by high performance liquid chromatography with fluorescence detection

Objective A HPLC-FLD method was developed to determine the levels of serum AAA in CRI patients, and to study the variation of serum AAA in CRI patients and its clinical significances. MethodsSerum samples were collected from 100 health controls and 80 CRI patients. According to 2002 National Kidney Foundation (NKF) staging diagnosis, CRI patients included 4 of stage 2, 12 of stage 3, 12 of stage 4, 52 of stage 5. According to pathogenesis, CRI patients were also divided into 3 groups :chronic nephritis group ( n = 32), DM group ( n = 36), hypertension group ( n = 12 ).Serums were deproteinized by equal volume of 5％ (v/v) PCA and supernate were analyzed direcdy. External standard method was used as quantitative method. The analytical column was Megres C18. 10％ acetonitrile in water was used as mobile phase. Flow rote was 1.0 ml/min. The wavelengths of fluorescence excitation and emission were changed with specific time. The levels of Tyr, Phe and Trp in CRI groups, different CKD stages and different pathogenesis were compared with healthy control groups to evaluated the sensitivity and specificity of serum AAA for CRI diagnosis. Results The linear ranges of the method were 0. 550 -275.000, 3. 050 - 1220. 000 and 0. 049 -49. 000 pμmol/L for Tyr, Phe and Trp, respectively. The limit of detection (LOD) was 0.014 μmol/L for Tyr, 0.500μmol/L for Phe, and 0.005 μmol/L for Trp. The average recovery was 100. 9％, 101.3％ and 98. 5％ for Tyr, Phe and Trp, respectively. Intra-day CVwas 3. 18％ -4. 20％ ( mean was 3. 13％ )and inter-day CV was 3. 18％ -4. 20％ ( mean was 3. 58％ ). The concentration of serum AAA, Tyr and Trp and the ratio of Tyr/Phe in CRI patients were( 135.74 ±23.23 )μmol/L, (52.27 +8.25) μmol/L, (21.49 ±4.25) μmol/L and0.87(0.68 - 1.05)]μmol/L. which were lower than that in healthy groups (t value was -14. 709, 4.452, 22. 100, U value was 266.000,respectively, P＜0. 05). The concentration of serum AAA, Tyr and Trp and the ratio of Tyr/Phe in healthy groups were ( 174. 47 ± 11.57 ) μmol/L, ( 63.53 ± 4. 68 ) μmol/L, (44. 22 ± 3. 67 ) μmol/L and0. 97(0. 94 - 1.00)]μmoL/L. There were no statistically significant difference between the different stage of CRI. Compared with the concentration of Tyr, Phe and Trp among chronic nephritis group, DM group,hypertension group, the concentration of Tyr had no significant changes among these three kinds of diseases (P ＞ 0. 05 ). The concentration of Phe had significant changes between Chronic nephritis group and DM group, Chronic nephritis group and hypertension group ( U = 395.00, 114. 00, P ＜ 0. 05 ) ; the concentration of Trp haad significant changes between Chronic nephritis group and DM group ( U = 349.00, P ＜ 0. 05 ).The diagnostic sensitivity and specificity of serum AAA for CRI were 90％ (72/80) and 100. 0％ (100/100).Conclusions The method of high-performance liquid chromatography with fluorescence detection ( HPLC-FLD) is simple, rapid, sensitive and specific. Simultaneous determination of serum AAA was benefit to the diagnosis and evaluation of CRI patients.