title: Intracisternal enzyme replacement therapy in lysosomal storage diseases: dispersal pathways, regional enzyme concentrations and the effect of posttreatment posture.
abstract: OBJECTIVE
  To investigate routes of dispersal of enzyme, its regional uptake and the effect of posture when replacement enzyme is administered directly into the cerebrospinal fluid (CSF).
  
  
  METHODS
  Dispersal pathways of particles and solutes were investigated using intracisternal injections of india ink with visual assessment, and a contrast medium (Iohexol) with computer tomography (CT). Replacement enzyme was measured at 46 loci within the central nervous system (CNS) in four groups of dogs subjected to different post-injection postural changes.
  
  
  RESULTS
  India ink and CT studies showed dispersal pathways for CSF to be mainly via cisterns and sulci. Replacement enzyme reached all areas of the CNS tested, although mean concentrations varied 49-fold over different areas of the brain. Posttreatment posture had only modest effects on enzyme uptake in limited anatomical sites.
  
  
  CONCLUSIONS
  Dispersal of solutes after injection is rapid and initially enhanced by the injection process. Preferential pathways for CSF flow in the subarachnoid spaces of the brain involve cisterns and sulci. The splenial and suprasplenial sulci in particular appear important conduits for dispersal to more dorsal and rostral areas of the brain. Expansion and contraction of these sulci during brain pulsation is considered important to the forward flow of solutes in CSF through these compartments. Following intracisternal enzyme replacement therapy, enzyme reached all areas of the brain, but there was considerable disparity of enzyme uptake with some areas recording much higher levels than others. Posttreatment posture made only modest differences to enzyme uptake.
authors.affiliation: Institute of Veterinary, Animal and Biomedical Sciences, Massey University, Palmerston North, New Zealand.
authors.forename: R D
authors.initials: RD
authors.lastname: Jolly
authors.forename: N R
authors.initials: NR
authors.lastname: Marshall
authors.forename: J
authors.initials: J
authors.lastname: Marshall
authors.forename: A
authors.initials: A
authors.lastname: Hartman
authors.forename: K M
authors.initials: KM
authors.lastname: Hemsley
authors.forename: L K
authors.initials: LK
authors.lastname: Winner
mesh_terms: D000818:Animals; D001921:Brain / Q000201:enzymology*; D002244:Carbon / Q000008:administration & dosage; D002946:Cisterna Magna; D004285:Dogs; D056947:Enzyme Replacement Therapy / Q000379:methods*; D006867:Hydrolases / Q000032:analysis / Q000493:pharmacokinetics* / Q000627:therapeutic use; D016464:Lysosomal Storage Diseases / Q000628:therapy; D008297:Male; D011187:Posture
chemical_list: C028433:chinese ink; D002244:Carbon; D006867:Hydrolases; C022708:N-sulfoglucosamine sulfohydrolase