α-Klotho is unstable in human urine

被引：23
作者：
Adema, Aaltje Y. [1 ]
Vervloet, Marc G. [1 ,2 ]
Blankenstein, Marinus A. [3 ]
Heijboer, Annemieke C. [3 ]
机构：
[1] Vrije Univ Amsterdam, Med Ctr, Dept Nephrol, NL-1007 MB Amsterdam, Netherlands
[2] Vrije Univ Amsterdam, Med Ctr, Inst Cardiovasc Res VU ICaR VU, NL-1007 MB Amsterdam, Netherlands
[3] Vrije Univ Amsterdam, Med Ctr, Dept Clin Chem, NL-1007 MB Amsterdam, Netherlands
来源：
KIDNEY INTERNATIONAL | 2015年 / 88卷 / 06期
关键词：
catheter urine; protease inhibitor; stability; alpha-Klotho;
D O I：
10.1038/ki.2015.238
中图分类号：
R5 [内科学]; R69 [泌尿科学（泌尿生殖系疾病）];
学科分类号：
1002 ; 100201 ;
摘要：
alpha-Klotho is an interesting new biomarker in kidney and cardiovascular disease. As alpha-Klotho is primarily expressed in renal epithelial tissue, various papers have reported a-Klotho concentrations in urine. As these studies did not address the reliability of urinary alpha-Klotho measurements and as urine is known to be a complex milieu, we investigated the stability of alpha-Klotho in both fresh catheter and fresh voided urine. a-Klotho was measured in these fresh urine samples and in the same samples under several other conditions. Storage of fresh catheter urine for 3 h at 37 degrees C, comparable to storage in the bladder, led to a 82% decrease in a-Klotho concentrations. Compared with fresh voided urine, alpha-Klotho concentrations decreased on an average of 45 and 82% after storage at - 80 degrees C and - 20 degrees C, respectively. An additional freeze-thaw cycle further decreased alpha-Klotho concentrations. The addition of a protease inhibitor or 0.1% albumin partly prevented degradation in fresh voided urine. Thus, alpha-Klotho is highly unstable in urine. Future studies showing results of urinary alpha-Klotho should mention conservation conditions and prove the reliability of the alpha-Klotho measurements.
引用
收藏
页码：1442 / 1444
页数：3
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