Use of a commercial agarose gel for analysis of urinary glycosaminoglycans in mucopolysaccharidoses

Ana Carolina Breier,Jaqueline Cé,Janice Carneiro Coelho

doi:10.1590/s1984-82502016000400013

Ana Carolina Breier, Jaqueline Cé + Show 1 more

Open Access

https://doi.org/10.1590/s1984-82502016000400013

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Abstract

Mucopolysaccharidoses (MPS) are a group of inherited metabolic disorders caused by deficiency of enzymes that degrade glycosaminoglycans (GAGs). Urinary excretion of GAGs is a common feature of MPS, and is considered their major biomarker. We aimed to adapt the GAG electrophoresis method to a commercial agarose gel which would be able to separate urinary GAGs in a simpler way with good sensitivity and reproducibility. Urine samples from patients previously diagnosed with MPS I, IV, and VI were used as electrophoretic standards. Samples from patients on enzyme replacement therapy (ERT) were also assessed. Commercial agarose gel electrophoresis was effective, showing proper definition and separation of GAG bands. Detection sensitivity exceeded 0.1 µg and band reproducibility were consistent. GAG bands quantified in urine samples from patients on ERT correlated very strongly (correlation coefficient = 0.98) with total GAG concentrations. This application of gel electrophoresis demonstrates the possibility of monitoring patients with MPS treated with ERT by analyzing separately the GAGs excreted in urine. We suggest this process should be applied to MPS screening as well as to follow-up of patients on treatment.

Highlights

Mucopolysaccharidoses (MPS) are a group of inherited metabolic disorders caused by a deficiency of enzymes needed for the degradation of glycosaminoglycans (GAGs)
The sensitivity and reproducibility of the commercial agarose gel electrophoresis technique were demonstrated through GAG standard curves obtained with 0.25, 0.5, 1.0, and 2.0 mg/mL solutions
The principles of electrophoretic techniques described in the literature were adapted to a commercial agarose gel, yielding good results in terms of GAG band separation and definition

Summary

Introduction

Mucopolysaccharidoses (MPS) are a group of inherited metabolic disorders caused by a deficiency of enzymes needed for the degradation of glycosaminoglycans (GAGs). Several research groups have been developing methods for the analysis of urinary GAG levels as a tool to be used in the diagnosis and follow-up of MPS treatment through enzyme replacement therapy (ERT), which is currently available for MPS I, II, and VI (Aurays-Blais et al, 2011). This treatment has brought new perspectives to patients, as it can slow the progression of the disease by correcting the enzyme deficiency and, reducing GAG accumulation. Agarose gel electrophoresis provides good visualization and definition of GAG bands (Coppa et al, 2012)

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