Mayo Clinic College of Medicine, Rochester, MN.
J Appl Lab Med. 2020 May 1;5(3):558-568. doi: 10.1093/jalm/jfaa023.
Advanced glycation end products (AGEs) are formed via the nonenzymatic glycation of sugars with amino acids. Two AGEs, Nε-(1-carboxymethyl)-L-Lysine (CML) and pentosidine, have been observed to be elevated in subjects suffering from a multitude of chronic disease states, and accumulation of these compounds may be related to the pathophysiology of disease progression and aging.
We describe here the development and validation of a specific and reproducible LC-MS/MS method to quantify CML and pentosidine in human serum with lower limits of quantitation of 75 ng/mL and 5 ng/mL, respectively. The analyte calibration curve exhibited excellent linearity at a range of 0-10 900 ng/mL for CML and 0-800 ng/mL for pentosidine. High-low linearity of 5 serum pairs was assessed, with a mean recovery of 103% (range 94-116%) for CML, and 104% (range 97-116%) for pentosidine.
Serum concentrations of CML and pentosidine were quantified in 30 control and 30 subjects with chronic renal insufficiency. A significant increase in both analytes was observed in renal failure compared to control subjects (2.1-fold and 8.4-fold, respectively; P < 0.001 for both). In a separate cohort of 49 control versus 95 subjects with type 2 diabetes mellitus (T2DM), serum CML but not serum pentosidine, was significantly elevated in the T2DM patients, and CML was also correlated with glycemic control, as assessed by hemoglobin A1c (r = 0.34, P < 0.001).
These mass spectroscopy-based assays for serum CML and pentosidine should be useful in accurately evaluating circulating levels of these key AGEs in various disease states.
晚期糖基化终产物（AGEs）是由糖与氨基酸的非酶糖化形成的。已经观察到两种 AGE，Nε-（1-羧甲基）-L-赖氨酸（CML）和戊糖素，在患有多种慢性疾病状态的受试者中升高，并且这些化合物的积累可能与疾病进展和衰老的病理生理学有关。
我们在这里描述了一种特定且可重复的 LC-MS/MS 方法的开发和验证，用于定量人血清中的 CML 和戊糖素，其定量下限分别为 75ng/mL 和 5ng/mL。分析物校准曲线在 CML 的 0-10900ng/mL 范围内和戊糖素的 0-800ng/mL 范围内表现出极好的线性。对 5 对高低血清进行了线性评估，CML 的平均回收率为 103%（范围为 94-116%），戊糖素的回收率为 104%（范围为 97-116%）。
在 30 名对照和 30 名慢性肾功能不全患者中定量了血清 CML 和戊糖素的浓度。与对照受试者相比，肾功能衰竭患者的两种分析物均显著增加（分别为 2.1 倍和 8.4 倍；两者均 P<0.001）。在另一组 49 名对照与 95 名 2 型糖尿病患者（T2DM）中，T2DM 患者的血清 CML 而非血清戊糖素显著升高，并且 CML 与糖化血红蛋白（HbA1c）评估的血糖控制也相关（r=0.34，P<0.001）。
这些基于质谱的血清 CML 和戊糖素测定法应可用于准确评估各种疾病状态下这些关键 AGEs 的循环水平。
