A Metabolomic Study Reveals Novel Plasma Lyso-Gb3 Analogs As Fabry Disease Biomarkers

Diurnal Variation of Urinary Fabry Disease Biomarkers during Enzyme Replacement Therapy Cycles

Fabry disease is an X-linked lysosomal storage disorder caused by mutations in the GLA gene encoding the α-galactosidase A enzyme. This enzyme cleaves the last sugar unit of glycosphingolipids, including globotriaosylceramide (Gb₃), globotriaosylsphingosine (lyso-Gb₃), and galabiosylceramide (Ga₂). Enzyme impairment leads to substrate accumulation in different organs, vascular endothelia, and biological fluids. Enzyme replacement therapy (ERT) is a commonly used treatment. Urinary analysis of Gb₃ isoforms (different fatty acid moieties), as well as lyso-Gb₃ and its analogues, is a reliable way to monitor treatment. These analogues correspond to lyso-Gb₃ with chemical modifications on the sphingosine moiety (−C₂H₄, −C₂H₄+O, −H₂, −H₂+O, +O, +H₂O₂, and +H₂O₃). The effects of sample collection time on urinary biomarker levels between ERT cycles were not previously documented. The main objective of this project was to analyze the aforementioned biomarkers in urine samples from seven Fabry disease patients (three treated males, three treated females, and one ERT-naïve male) collected twice a day (morning and evening) for 42 days (three ERT cycles). Except for one participant, our results show that the biomarker levels were generally more elevated in the evening. However, there was less variability in samples collected in the morning. No cyclic variations in biomarker levels were observed between ERT infusions.

High-Risk Screening for Fabry Disease: Analysis by Tandem Mass Spectrometry of Globotriaosylceramide (Gb3 ) in Urine Collected on Filter Paper

Fabry disease is a complex, panethnic lysosomal storage disorder. It is characterized by the accumulation of glycosphingolipids in tissues, organs, the vascular endothelium, and biological fluids. The reported incidence in different populations is quite variable, ranging from 1:1400 to 1:117,000. Its complexity lies in the marked genotypic and phenotypic heterogeneity. Despite the fact that it is an X-linked disease, more than 600 mutations affect both males and females. In fact, some females may be affected as severely as males. The purpose of this protocol is to focus on the high-risk screening of patients who might have Fabry disease using a simple, rapid, non-invasive high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method for urinary globotriaosylceramide (Gb₃ ) analysis. Urine filter paper samples are easily collected at home by patients and sent by regular mail. This method has been successfully used for high-risk screening of patients with ophthalmologic manifestations and in an on-going study for high-risk screening of Fabry disease in patients with chronic kidney diseases. © 2017 by John Wiley & Sons, Inc.

High-Risk Screening of Fabry Disease: Analysis of Fifteen Urinary Methylated and Non-Methylated Gb3 Isoforms Using Tandem Mass Spectrometry

Fabry disease is a multisystemic, X-linked lysosomal storage disorder caused by mutations in the GLA gene, leading to α-galactosidase A deficiency and resulting in the accumulation of glycosphingolipids in different tissues and biological fluids. Glycosphingolipid biomarkers, such as globotriaosylceramide (Gb₃ ) isoforms, globotriaosylsphingosine (lyso-Gb₃ ) and related analogs, and galabiosylceramide (Ga₂ ) isoforms and analogs, are found to be abnormally increased in urine and in plasma of Fabry patients and have the potential to be used as specific biomarkers of the disease. This unit presents a protocol for the relative quantification of fifteen urinary isoforms of Gb₃ analyzed simultaneously with creatinine by ultra-performance liquid chromatography (UPLC) coupled to tandem mass spectrometry (MS/MS). In order to purify urine samples, a liquid-liquid extraction is performed and samples are analyzed by MS/MS in positive electrospray ionization mode. These biomarkers are useful for screening, diagnosis, and long-term monitoring of Fabry disease patients. We have shown that the methylated Gb₃ isoforms are particularly useful for screening Fabry patients who present with late-onset cardiac variant mutations. © 2016 by John Wiley & Sons, Inc.

Tandem Mass Spectrometry Quantitation of Lyso-Gb3 and Six Related Analogs in Plasma for Fabry Disease Patients

Fabry disease is an X-linked lysosomal storage disorder, caused by a deficit in α-galactosidase A enzyme activity, leading to the storage of sphingolipids such as globotriaosylsphingosine (lyso-Gb3 ), globotriaosylceramide (Gb3 ), and galabiosylceramide (Ga2 ) in organs, tissues and biological fluids. A recent metabolomic study performed in plasma revealed lyso-Gb3 analogs as novel Fabry disease biomarkers. These molecules correspond to lyso-Gb3 with different chemical modifications on the sphingosine chain (-C2 H4 , -H2 , +O, +H2 O, +H2 O2, and +H2 O3 ). An ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method was developed and validated for the multiplex analysis of lyso-Gb3 and its 6 analogs in plasma. The samples are prepared by solid phase extraction using mixed-mode strong cation exchange (MCX) cartridges. An in-house synthesized N-glycinated lyso-Gb3 derivative was used for the internal standard. The limits of detection (LODs) measured for lyso-Gb3 and its analogs ranged from 0.06 to 0.29 nM. © 2016 by John Wiley & Sons, Inc.

Fabry Disease Biomarkers: Analysis of Urinary Lyso-Gb3 and Seven Related Analogs Using Tandem Mass Spectrometry

Fabry disease is an X-linked lysosomal storage disorder caused by the absence or reduction of the enzyme α-galactosidase A activity. Currently, globotriaosylsphingosine (lyso-Gb3 ) and globotriaosylceramide (Gb3 ) are used as biomarkers to diagnose and monitor Fabry patients. However, recent metabolomic studies have shown that several glycosphingolipids are also elevated in biological fluids of affected patients and may be related to disease manifestations. This unit describes a multiplex methodology targeting the analysis of urinary lyso-Gb3 and seven structurally related analogs. A solid-phase extraction process is performed, then lyso-Gb3 and its analogs are analyzed simultaneously with an internal standard by ultra-performance liquid chromatography (UPLC) coupled to a tandem mass spectrometry (MS/MS) system. This methodology can be useful for the diagnosis of Fabry patients, including patients with cardiac variant mutations, but also to monitor the efficacy of therapeutic interventions, considering that lyso-Gb3 analogs are more elevated than lyso-Gb3 itself in urine. © 2016 by John Wiley & Sons, Inc.