This study tested intrathecal enzyme replacement therapy (ERT) in a mouse model of infantile Batten disease. Mice lacking the enzyme palmitoyl-protein thioesterase 1 (PPT1) received a single intrathecal injection of recombinant human PPT1 at 6 weeks of age. This prevented decline in motor function, improved survival, and reduced brain and spinal cord pathology compared to untreated mice. The effects were similar to ERT for another form of Batten disease. This suggests intrathecal ERT may help treat infantile Batten disease caused by PPT1 deficiency in humans.

1. Intrathecal enzyme replacement therapy in a preclinical model:
Infantile Batten Disease
Jui-Yun Lu1,3, Hemanth R. Nelvagal4, Lingling Wang1,3, Shari G. Birnbaum2, Jonathan D. Cooper4 and Sandra L. Hofmann1,3
From the Departments of 1Internal Medicine, 2Psychiatry, and the 3Hamon Center for Therapeutic Oncology Research, University of Texas Southwestern Medical Center, Dallas, TX 75390-8593,
USA, and the 4Pediatric Storage Disorders Laboratory, Department of Basic and Clinical Neuroscience, King’s Health Partners Centre for Neurodegeneration, James Black Centre, Institute of
Psychiatry, Psychology & Neuroscience, King’s College London, 125 Coldharbour Lane, London SE5 9NU, UK
INTRODUCTION
Infantile Batten disease is caused by deficiency
in an enzyme, palmitoyl-protein thioesterase
(PPT1). Lack of PPT1 activity causes
accumulation of material in the lysosomal
compartment of cells. Experience in other
lysosomal disease shows that administration of
the missing enzyme (enzyme replacement
therapy, ERT) by direct delivery to the spinal
fluid may be helpful in preventing further
accumulation and arresting progression of the
disease. In this study we tested a preparation of
the enzyme in mice. Treatment was given on
three consecutive days in PPT1 knockout mice at
6 weeks of age.
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Fig. 2. Effect of intrathecal (IT) ERT on latency to fall from a constant
speed rotating rod (Rotarod). All tests were terminated after 60
seconds. (A) Two trials were conducted daily on each of three
consecutive days at 3, 5, 6, 7, 8, and 9 months of age. Maximum
latency to fall on the third testing day is reported. (B)Detail of trial
results at age 7 months. Individual trials on each of the three testing
days are shown.
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WHAT THIS MEANS FOR THERAPY
PPT1 injected into the cerebrospinal fluid at the
lumbar area of mice (intrathecal injection)
prevented decline in motor function and improved
survival of mice with the CLN1 form of Batten
Disease. The treatment was only given at one point
in time but had a measurable effect. The effect was
similar to the effect seen for CLN2 enzyme in the
CLN2 mouse model. CLN2 enzyme (TPP1) is
currently being administered to late infantile Batten
children through the cerebrospinal fluid. If this
approach is helpful in CLN2 disease, our results
suggest that the same approach would be helpful
in CLN1 disease.
Fig. 3. Effect of IT ERT on disease-specific (A) and overall (B)
survival. Both disease-specific (p<0.001) and overall survival
(p<0.001) were improved. Higher doses were more effective.
Disease-specific mean survivals were 238, 233, 267, 272, and
284 days for control (uninjected), 0, 2.6, 5,3, 10.6 mg/ml PPT1
injected groups, respectively.
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Fig. 6. PPT1 can be found in the brain of the
Ppt1 knockout mouse cerebellum at varying
times after intrathecal injection. (A) Ppt1
knockout mouse, age 6 weeks, injected with
aCSF (B-D) Ppt1 knockout mice, age 6 weeks,
injected with 10 .6 mg/ml PPT1 and sacrificed
at 1 day (B), 3 weeks (C) or 5 months (D)
after the injection. (E) Wild-type control mouse
brain. Brown staining indicates PPT1
immunostaining. Bar, 20 microns.
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Fig. 4 and 5. IT ERT improves brain and spinal cord
pathology. Fig. 4 shows the microglial marker CD68 from
three randomly selected 7 month-old mice from each
group indicated and Fig. 5 shows autofluorescent storage
material. Different areas of the brain and spinal cord are
shown. (A) S1 barrel field cortex (B) VPM/VPL; (C) LGnD;
(D) Dorsal cervical spinal cord (E) Ventral cervical spinal
cord (F) Dorsal lumbar spinal cord (G) Ventral lumbar
spinal cord.
Fig. 1. Experimental design. Four groups of 16-20
Ppt1 knockout mice at six weeks of age were
randomized to receive three consecutive daily
lumbar spinal infusions of human recombinant
PPT1 in 80 µl over 8 minutes at concentrations of
0, 2.6, 5.3 or 10.6 mg/ml. Rotarod testing was
performed by a blinded observer at 3, 5, 6, 7, 8
and 9 months of age. Three mice from each
group were sacrificed at seven months for
pathological examination. Unmanipulated groups
of wild-type and Ppt1 knockout mice (n=15) were
tested for comparison.
Acknowledgements: The authors wish to thank
Drs. Peter Lobel and David Sleat for advice on
the experimental design, Dr. James Richardson
and John Shelton of the UT Southwestern
Molecular Pathology Core for PPT1
immunostaining and microscopy, and Lauren
Peca for performing the behavioral tests. This
work was funded by Taylor’s Tale, the Batten
Disease Support and Research Association, the
Batten Disease Family Association, and a King’s
College London Graduate School International
Studentship award to HRN.