Effect of cisternal sulfamidase delivery in MPS IIIA Huntaway dogs--a proof of principle study.
Mucopolysaccharidosis type IIIA (MPS IIIA) results from lack of functional sulfamidase (SGSH), a lysosomal enzyme. Its substrate, heparan sulfate, and other secondarily-stored compounds subsequently accumulate primarily within the central nervous system (CNS), resulting in progressive mental deterioration and early death. Presently there is no treatment. As a potential therapeutic strategy, recombinant human sulfamidase (rhSGSH) was administered into the CSF (via the cerebellomedullary cistern) of three adult MPS IIIA dogs either twice with a 4 day interval, or weekly for up to 4 weeks. The dogs were euthanased 24 h post-injection along with one untreated unaffected and two MPS IIIA controls. We have examined the three dimensional pattern of distribution of enzyme in the CNS and its ability to reduce primary substrate storage. High concentrations of rhSGSH protein, with up to 39-fold normal enzyme activity levels were detected within widespread areas of the CNS. RhSGSH protein was also detectable by immunohistochemistry in neurons and glia in all three enzyme-treated dogs. In both weekly-treated dogs, relative levels of a heparan sulfate-derived disaccharide, measured using tandem mass spectrometry, were lower in many brain regions when compared to untreated MPS IIIA controls. A moderately severe meningitis was also present as well as antibodies to rhSGSH in CSF/plasma. These findings demonstrate proof of principle that MPS IIIA can be treated by intracisternal enzyme replacement warranting further experiments in animals tolerant to rhSGSH. This enzyme delivery method may represent a means of treating neuropathology in MPS IIIA and other lysosomal storage disorders affecting the CNS.
Hemsley
Kim M
KM
Lysosomal Diseases Research Unit, Dept. Genetics and Molecular Pathology, SA Pathology, Women's and Children's Hospital, North Adelaide, SA 5006, Australia. Kim.Hemsley@adelaide.edu.au
Norman
Elizabeth J
EJ
Crawley
Allison C
AC
Auclair
Dyane
D
King
Barbara
B
Fuller
Maria
M
Lang
Debbie L
DL
Dean
Caroline J
CJ
Jolly
Robert D
RD
Hopwood
John J
JJ
D000818:Animals; D000906:Antibodies / Q000097:blood / Q000134:cerebrospinal fluid; D001921:Brain / Q000473:pathology; D004285:Dogs; D004333:Drug Administration Routes; D056947:Enzyme Replacement Therapy; D005944:Glucosamine / Q000378:metabolism; D006497:Heparan Sulfate / Q000378:metabolism; D006801:Humans; D006867:Hydrolases / Q000008:administration & dosage* / Q000134:cerebrospinal fluid / Q000276:immunology / Q000627:therapeutic use*; D056724:Immunity, Humoral / Q000276:immunology; D007150:Immunohistochemistry; D008099:Liver / Q000473:pathology; D009084:Mucopolysaccharidosis III / Q000276:immunology / Q000473:pathology / Q000628:therapy*; D011994:Recombinant Proteins / Q000008:administration & dosage / Q000627:therapeutic use; D013997:Time Factors; D014020:Tissue Extracts
D000906:Antibodies; D005944:Glucosamine; D006497:Heparan Sulfate; D006867:Hydrolases; D011994:Recombinant Proteins; D014020:Tissue Extracts; C022708:N-sulfoglucosamine sulfohydrolase