Figure 4.

Histology and IHC Analysis of Neonatal MPS I Mice after Treatment with PS822

(A–C) Columns show tissues from normal mice (A), untreated MPS I mice (B), and treated MPS I mice (C). The upper panel shows H&E staining of liver. Untreated MPS I mice have several foam cells (the hallmark of MPS I) present but these are absent in the treated MPS I and normal mice. The middle panel shows H&E staining of cerebellum. The Purkinje neurons in untreated MPS I mice have cytoplasmic cellular vacuolation (arrows), which is absent in high-dose MPS I treated and normal mice. The lower panel shows IHC for IDUA. There is a subtle but slightly increased intensity of signal in the choroid plexus of treated MPS I mice, which is suggestive of the presence of enzyme in the brain. Also, occasional individual choroid plexus epithelial cells (arrows) are strongly immunopositive for IDUA.