IMR Press / FBL / Volume 28 / Issue 2 / DOI: 10.31083/j.fbl2802039
Open Access Original Research
The Application of HPLC-FLD and NMR in the Monitoring of Therapy Efficacy in Alpha-Mannosidosis
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1 Centre of Glycomics, Institute of Chemistry, Slovak Academy of Sciences, 84538 Bratislava, Slovakia
2 Centre for Inherited Metabolic Disorders, National Institute of Children's Diseases, 83340 Bratislava, Slovakia
3 Department of Paediatrics, Faculty of Medicine, Comenius University in Bratislava, and National Institute of Children's Diseases, 83340 Bratislava, Slovakia
*Correspondence: (Zuzana Pakanová)
Front. Biosci. (Landmark Ed) 2023, 28(2), 39;
Submitted: 29 December 2022 | Revised: 24 January 2023 | Accepted: 9 February 2023 | Published: 28 February 2023
(This article belongs to the Special Issue Lysosomal Storage Disorders)
Copyright: © 2023 The Author(s). Published by IMR Press.
This is an open access article under the CC BY 4.0 license.

Background: Alpha-mannosidosis is a rare lysosomal storage disorder, caused by decreased activity of α-D-mannosidase. This enzyme is involved in the hydrolysis of mannosidic linkages in N-linked oligosaccharides. Due to the mannosidase defect, undigested mannose-rich oligosaccharides (Man2GlcNAc - Man9GlcNAc) accumulating in cells are excreted in large quantities in urine. Methods: In this work, we determined the levels of urinary mannose-rich oligosaccharides in a patient subjected to novel enzyme replacement therapy. Urinary oligosaccharides were extracted using solid phase extraction (SPE), labeled by fluorescent tag 2-aminobenzamide, and quantified by high-performance liquid chromatography (HPLC) with fluorescence detector (FLD). The identity of peaks was determined by matrix-assisted laser desorption/ionization time-of-flight/time-of-flight (MALDI-TOF/TOF) mass spectrometry. In addition, the levels of urinary mannose-rich oligosaccharides were also quantified by 1H nuclear magnetic resonance (NMR) spectroscopy. The data were analyzed using one-tailed paired t-test and Pearson’s correlation tests. Results: Compared to levels before the administration of therapy, an approximately two-folds decrease in total mannose-rich oligosaccharides after one month of treatment was observed by NMR and HPLC. After four months, an approximately ten-folds significant decrease in total urinary mannose-rich oligosaccharides was detected, suggesting therapy effectiveness. A significant decrease in the levels of oligosaccharides with 7–9 mannose units was detected by HPLC. Conclusions: The application of both HPLC-FLD and NMR in quantification of oligosaccharide biomarkers is a suitable approach for monitoring of therapy efficacy in alpha-mannosidosis patients.

mass spectrometry
velmanase alpha
2019/7-CHÚSAV-4/Ministry of Health of Slovak Republic
VEGA 2/0060/21/Ministry of Health of Slovak Republic
313021Y920/European Regional Development Fund
Fig. 1.
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