Effect of high dose, repeated intra‐cerebrospinal fluid injection of sulphamidase on neuropathology in mucopolysaccharidosis type IIIA mice

Abstract

Mucopolysaccharidosis type IIIA (MPS IIIA) is an inherited neurodegenerative lysosomal storage disorder characterized by progressive loss of learned skills, sleep disturbance and behavioural problems. Reduced activity of sulphamidase (N-sulphoglucosamine sulphohydrolase; SGSH; EC 3.10.1.1) results in intracellular accumulation of heparan sulphate (HS), with the brain as the primary site of pathology. We have used a naturally occurring MPS IIIA mouse model to determine the effectiveness of SGSH replacement through the cerebrospinal fluid (CSF) to decrease neuropathology. This is a potential therapeutic option for patients with this disorder. Mice received intra-CSF injections of recombinant human SGSH (30, 50 or 70 mg) fortnightly from 6 to 18 weeks of age, and the cumulative effect on neuropathology was examined and quantified. Anti-SGSH antibodies detected in plasma at euthanasia did not appear to impact upon the health of the mice or the experimental outcome, with significant but regiondependent and dose-dependent reductions in an HSderived oligosaccharide observed in the brain and spinal cord using tandem mass spectrometry. SGSH infusion reduced the number of storage inclusions observed in the brain when visualized using electron microscopy, and this correlated with a significant decrease in the immunohistochemical staining of a lysosomal membrane marker. Reduced numbers of activated isolectin B4-positive microglia and glial fibrillary acidic protein-positive astrocytes were seen in many, but not all, brain regions. Significant reductions in the number of ubiquitin-positive intracellular inclusions were also observed. These outcomes show the effectiveness of this method of enzyme delivery in reducing the spectrum of neuropathological changes in murine MPS IIIA brain.

Whole body correction of mucopolysaccharidosis IIIA by intracerebrospinal fluid gene therapy

“…Preclinical studies of intrathecal delivery of a recombinant enzyme (39,(59)(60)(61), now being translated to humans (NCT01155778 and NCT01299727, clinicaltrials.gov), confirm that an increase in sulfamidase levels in CSF can be effective in counteracting the pathological changes associated with MPS IIIA and further support the rationale of our study. While we showed safety and efficacy in MPS IIIA mice and evidence of widespread transgenic expression in dogs using i.c.…”

Intrathecal recombinant human 4-sulfatase reduces accumulation of glycosaminoglycans in dura of mucopolysaccharidosis VI cats

“…These results were similar to those found in mature immunotolerized MPS-VI cats (14) and support the contention that repeated IT-INJ is a safe and efficacious means of regularly administering enzyme into the CNS in MPS-VI and other lysosomal storage disorders for which development of paresis needs to be prevented (6,7) or in which brain function is impaired (16,(23)(24)(25)28,29).…”

“…MPS-I dogs treated intrathecally with recombinant human iduronidase developed serum and CSF antibodies against the enzyme, as well as meningitis (15,16). Similarly, intrathecally treated MPS-IIIA dogs developed antibodies against recombinant human sulfamidase, as well as meningitis (23), whereas MPS-IIIA mice treated with repeated IT-INJs of the same enzyme developed circulating antibodies without meningitis or adverse reactions (24)(25)(26). The small, focal, Wallerian-type degeneration observed near the site of IT-INJ in most intrathecally treated cats, irrespective of presence or absence of polysorbate-80, was attributed to mild iatrogenic trauma produced during IT-INJ, as previously reported (14), again highlighting the importance of a good injection technique (14).…”

Safety Evaluation of Chronic Intrathecal Administration of Idursulfase-IT in Cynomolgus Monkeys

“…Using the same model, monthly and quarterly dosing of IT recombinant human iduronidase with concomitant IV dosing resulted in supranormal enzyme levels in the brain, as well as reductions in GAG storage (Dickson et al 2007). In other studies, the injection of recombinant human sulfamidase into the cisterna magna in a naturally occurring mouse model of MPS IIIA resulted in a dose-dependent reduction in the level of heparan sulfate-derived oligosaccharides (Hemsley et al 2007;Hemsley et al 2008;Hemsley, Luck et al2009) and behavioral improvements (Hemsley et al 2007;Hemsley, Luck et al 2009). Intrathecal treatment with recombinant human N-acetylgalactosamine 4-sulfatase in a feline model of MPS VI resulted in a reduction of oligosaccharide fragments in the CSF and vacuolization in the dura mater (Auclair et al 2010).…”

“…Different methods of achieving effective CNS ERT levels have been studied, including administration of high IV doses (Vogler et al 2005), the use of epinephrine (Urayama et al 2007), direct infusion into the striatal region of the brain (Zirzow et al 1999), chemical modification of the infused enzyme (Grubb et al 2008), and direct intrathecal (IT) injection into the cerebrospinal fluid (CSF) via lumbar or cisterna magna puncture (Auclair et al 2010;Dickson et al 2007;Hemsley et al 2007Hemsley et al , 2008Hemsley, Norman et al 2009;Kakkis et al 2004;Muñoz-Rojas et al 2008. Intrathecal administration of ERT for the treatment of lysosomal storage diseases has shown efficacy in various animal models (Auclair et al 2010;Dickson et al 2007;Hemsley et al 2007Hemsley et al , 2008Hemsley, Norman et al 2009;Kakkis et al 2004), including a mouse model of MPS IIIA (Sanfilippo syndrome; Hemsley et al 2007Hemsley et al , 2008 and canine models of MPS IIIA (Hemsley, Norman et al 2009) and MPS I (Hurler syndrome; Kakkis et al 2004). Dose-dependent reductions in heparan sulfatederived oligosaccharides were accompanied by improvements in pathology and behavior (Hemsley et al 2007).…”