Elsevier

Clinica Chimica Acta

Volume 413, Issues 15–16, 16 August 2012, Pages 1207-1210
Clinica Chimica Acta

A new method for the measurement of lysosomal acid lipase in dried blood spots using the inhibitor Lalistat 2

https://doi.org/10.1016/j.cca.2012.03.019Get rights and content
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Abstract

Background

Cholesterol ester storage disease (CESD) and Wolman Disease (WD) are due to deficiency of lysosomal acid lipase (LAL). A new method is described for the measurement of LAL in dried blood spots (DBS) using Lalistat 2 an inhibitor of LAL.

Methods

LAL activity in DBS extracts was measured using the substrate 4-methylumbelliferyl palmitate. LAL activity was determined by measuring total lipase activity and lipase activity in the presence of Lalistat 2. The specificity of Lalistat 2 was investigated using human recombinant LAL (hrLAL) and human pancreatic lipase (hPL).

Results

Lalistat 2 inhibited hrLAL with 1% residual activity at 1 μM inhibitor but had no effect on hPL up to 10 μM. LAL activity in DBS samples obtained from normal controls (n = 140) was 0.50–2.30 nmol/punch/h and in patients with CESD was < 0.03 nmol/punch/h (n = 11). Activity in carriers showed intermediate activity: 0.15–0.40 nmol/punch/h (n = 15).

Conclusions

Measurement of LAL using DBS is made difficult by the presence of other lipases in whole blood. Lalistat 2 is a specific inhibitor of LAL which allows the determination of LAL in DBS. Results show the method differentiates clearly between normal controls, carriers and affected cases.

Highlights

► DBS method for LAL. ► Inhibitor – Lalistat 2 ► Clear identification of affected cases – CESD and WD.

Keywords

Lysosomal acid lipase
Dried blood spot
Method
Lalistat 2
Wolman disease
Cholesterol ester storage disease

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