Advantages of using same species enzyme for replacement therapy in a feline model of mucopolysaccharidosis type VI

In a feline model of mucopolysaccharidosis type VI (IMPS VI), recombinant f eline N-acetylgalactosamine-4-sulfatase (rf4S) administered at a dose of 1 mg/kg of body weight, altered the clinical course of the disease in two aff ected cats treated from birth. After 170 days of therapy, both cats were ph ysically indistinguishable from normal cats with the exception of mild corn eal clouding. Feline N-acetylgalactosamine-4-sulfatase was effective in red ucing urinary glycosaminoglycan levels and lysosomal storage in all cell ty pes examined except for corneal keratocytes and cartilage chondrocytes. In addition, skeletal pathology was nearly normalized as assessed by radiograp hic evidence and bone morphometric analysis. Comparison of results with a p revious study in which recombinant human 4S (rh4S) was used at an equivalen t dose and one 5 times higher indicated that rf4S had a more pronounced eff ect on reducing pathology than the same dose of rh4S, and in some instances such as bone pathology and lysosomal storage in aorta smooth muscle cells, it was as good as, or better than, the higher dose of rh4S. We conclude th at in the feline MPS VI model the use of native or same species enzyme for enzyme replacement therapy has significant benefits.