A practical fluorometric assay method to measure lysosomal acid lipase activity in dried blood spots for the screening of cholesteryl ester storage disease and Wolman disease

作者：Dairaku Takenori; Iwamoto Takeo; Nishimura Minami; Endo Masahiro; Ohashi Toya; Eto Yoshikatu^*

来源：Molecular Genetics and Metabolism, 2014, 111(2): 193-196.

DOI：10.1016/j.ymgme.2013.11.003

• 4-Methylumbelliferone
• Excitation wavelength
• Full width at half maximum
• Lysosomal acid lipase
• Cholesteryl ester storage disease
• Wolman disease

Fluorometric measurements of 4-methylumbelliferone (4-MU) are generally used to screen lysosomal storage diseases (LSDs) using dried blood spots (DBSs). However, in DBS, it is difficult to measure lysosomal acid lipase (LAL) activity due to the influence of other lipases in whole blood. Recently, Hamilton used a fluorometric enzyme assay with 4-MU derivatives to measure the LAL activity in DBS. This method requires mercury chloride as stopping reagent, and the fluorescence intensity of 4-MU was measured at an acidic pH. We report a revised method to measure the LAL activity without using toxic mercury chloride and to measure the fluorescence intensity of 4-MU at a basic pH. For this measurement, we established a more practical method that does not require mercury chloride.
The LAL activity in DBS was measured in 51 normal controls, seven obligate carriers and seven patients with CESD. The average LAL activities +/- SD in the DBS from the normal, obligate carriers and CESD patients were 0.68 +/- 0.2 (range: 0.3-1.08), 0.21 +/- 0.1 (range: 0.11-0.41) and 0.02 +/- 0.02 (range: 0-0.06) nmol/punch/h, respectively. There was a significant difference between the normal and the CESD. Our method does not require toxic mercury chloride and is an appropriate revised enzyme assay using DBS for screening patients with CESD.

• 出版日期2014-2