title: Analysis of glycosaminoglycans in cerebrospinal fluid from patients with mucopolysaccharidoses by isotope-dilution ultra-performance liquid chromatography-tandem mass spectrometry.
abstract: BACKGROUND
  New therapies for the treatment of mucopolysaccharidoses that target the brain, including intrathecal enzyme replacement, are being explored. Quantitative analysis of the glycosaminoglycans (GAGs) that accumulate in these disorders is required to assess the disease burden and monitor the effect of therapy in affected patients. Because current methods lack the required limit of quantification and specificity to analyze GAGs in small volumes of cerebrospinal fluid (CSF), we developed a method based on ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS).
  
  
  METHODS
  Samples of CSF (25 μL) were evaporated to dryness and subjected to methanolysis. The GAGs were degraded to uronic acid-N-acetylhexosamine dimers and mixed with internal standards derived from deuteriomethanolysis of GAG standards. Specific dimers derived from heparan, dermatan and chondroitin sulfates (HS, DS and CS) were separated by UPLC and analyzed by electrospray ionization MS/MS using selected reaction monitoring for each targeted GAG product and its corresponding internal standard.
  
  
  RESULTS
  CSF from control pediatric subjects (n = 22) contained <0.38 mg/L HS, 0.26 mg/L DS, and 2.8 mg/L CS, whereas CSF from patients with Hurler syndrome (n = 7) contained concentrations of DS and HS that were at least 6-fold greater than the upper control limits. These concentrations were reduced by 17.5% to 82.5% after allogeneic transplantation and treatment with intrathecal and intravenous enzyme replacement therapy.
  
  
  CONCLUSIONS
  The method described here has potential value in monitoring patients with mucopolysaccharidoses receiving treatment targeted to the brain.
authors.affiliation: Duke University Medical Center, Pediatrics, Medical Genetics Division, Durham, NC, USA.
authors.forename: Haoyue
authors.initials: H
authors.lastname: Zhang
authors.forename: Sarah P
authors.initials: SP
authors.lastname: Young
authors.forename: Christiane
authors.initials: C
authors.lastname: Auray-Blais
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Orchard
authors.forename: Jakub
authors.initials: J
authors.lastname: Tolar
authors.forename: David S
authors.initials: DS
authors.lastname: Millington
mesh_terms: D015415:Biomarkers / Q000134:cerebrospinal fluid; D002138:Calibration; D002648:Child; D002809:Chondroitin Sulfates / Q000134:cerebrospinal fluid* / Q000592:standards; D002851:Chromatography, High Pressure Liquid; D003871:Dermatan Sulfate / Q000134:cerebrospinal fluid* / Q000592:standards; D003903:Deuterium; D019281:Dimerization; D056947:Enzyme Replacement Therapy; D018380:Hematopoietic Stem Cell Transplantation; D006497:Heparan Sulfate / Q000134:cerebrospinal fluid* / Q000592:standards; D006595:Hexosamines / Q000134:cerebrospinal fluid; D006801:Humans; D007201:Indicator Dilution Techniques; D007275:Injections, Intravenous; D007278:Injections, Spinal; D008059:Mucopolysaccharidosis I / Q000134:cerebrospinal fluid* / Q000628:therapy; D012015:Reference Standards; D012016:Reference Values; D053719:Tandem Mass Spectrometry; D014574:Uronic Acids / Q000134:cerebrospinal fluid
chemical_list: D015415:Biomarkers; D002809:Chondroitin Sulfates; D003871:Dermatan Sulfate; D003903:Deuterium; D006497:Heparan Sulfate; D006595:Hexosamines; D014574:Uronic Acids