Limits...
SAFETY AND TOLERABILITY OF MRI-GUIDED INFUSION OF AAV2-hAADC INTO THE MID-BRAIN OF NON-HUMAN PRIMATE.

San Sebastian W, Kells AP, Bringas J, Samaranch L, Hadaczek P, Ciesielska A, Macayan M, Pivirotto PJ, Forsayeth J, Osborne S, Wright JF, Green F, Heller G, Bankiewicz KS - Mol Ther Methods Clin Dev (2014)

Bottom Line: As a result, patients suffer compromised development, particularly in motor function.The objective of this study was to assess the long-term safety and tolerability of bilateral AAV2-hAADC MRI-guided pressurized infusion into the mid-brain of non-human primates.Our data indicate that effective mid-brain transduction was achieved without untoward effects.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurological Surgery, University of California San Francisco, San Francisco, CA, USA.

ABSTRACT

Aromatic L-amino acid decarboxylase (AADC) deficiency is a rare, autosomal-recessive neurological disorder caused by mutations in the DDC gene that leads to an inability to synthesize catecholamines and serotonin. As a result, patients suffer compromised development, particularly in motor function. A recent gene replacement clinical trial explored putaminal delivery of recombinant adeno-associated virus serotype 2 vector encoding human AADC (AAV2-hAADC) in AADC-deficient children. Unfortunately, patients presented only modest amelioration of motor symptoms, which authors acknowledged could be due to insufficient transduction of putamen. We hypothesize that, with the development of a highly accurate MRI-guided cannula placement technology, a more effective approach might be to target the affected mid-brain neurons directly. Transduction of AADC-deficient dopaminergic neurons in the substantia nigra and ventral tegmental area with locally infused AAV2-hAADC would be expected to lead to restoration of normal dopamine levels in affected children. The objective of this study was to assess the long-term safety and tolerability of bilateral AAV2-hAADC MRI-guided pressurized infusion into the mid-brain of non-human primates. Animals received either vehicle, low or high AAV2-hAADC vector dose and were euthanized 1, 3 or 9 months after surgery. Our data indicate that effective mid-brain transduction was achieved without untoward effects.

No MeSH data available.


Related in: MedlinePlus

AADC expression in the mid-brain of (a) pilot and (b) toxicology study animals. AADC staining of mid-brain revealed good correlation between infusate (gadolinium) signal in MRI and AAV2-hAADC expression (left and middle columns). AADC signal (brown) in SNpc and VTA that colocalized with endogenous tyrosine hydroxylase signal (blue, middle column). Although transgenic AADC in these nuclei was indistinguishable from endogenous AADC, AAV2-hAADC gene product was easily visible in SNpr when compared to naïve animal images. Higher magnification images show transgenic AADC staining in cells and fibers (right column). Scale bars: Left and middle columns: 1 cm; right column: 200 μm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4274790&req=5

fig3: AADC expression in the mid-brain of (a) pilot and (b) toxicology study animals. AADC staining of mid-brain revealed good correlation between infusate (gadolinium) signal in MRI and AAV2-hAADC expression (left and middle columns). AADC signal (brown) in SNpc and VTA that colocalized with endogenous tyrosine hydroxylase signal (blue, middle column). Although transgenic AADC in these nuclei was indistinguishable from endogenous AADC, AAV2-hAADC gene product was easily visible in SNpr when compared to naïve animal images. Higher magnification images show transgenic AADC staining in cells and fibers (right column). Scale bars: Left and middle columns: 1 cm; right column: 200 μm.

Mentions: Neurons in the SNpc and VTA express endogenous AADC that made difficult to distinguish transduced neurons from those not transduced in these nuclei. Nevertheless, the distribution and intensity of immunohistochemical AADC staining in the mid-brain of AAV2-hAADC-treated animals clearly showed increased AADC expression within the targeted area when compared to mid-brain staining in control animals (Figure 3a (pilot) and 3B (pivotal toxicology)). In some of the animals, transgenic hAADC signal was noted in the lateral SNpr, normally devoid of AADC, both in double chromogenic (Figure 3) and double immunofluorescent sections (Supplementary Figure S3). Histological sections in some of the animals revealed the cannula tract, thereby confirming optimal placement of the cannula and matching observed MRI tracer (Figure 2) in VTA and medial-lateral SNpc.


SAFETY AND TOLERABILITY OF MRI-GUIDED INFUSION OF AAV2-hAADC INTO THE MID-BRAIN OF NON-HUMAN PRIMATE.

San Sebastian W, Kells AP, Bringas J, Samaranch L, Hadaczek P, Ciesielska A, Macayan M, Pivirotto PJ, Forsayeth J, Osborne S, Wright JF, Green F, Heller G, Bankiewicz KS - Mol Ther Methods Clin Dev (2014)

AADC expression in the mid-brain of (a) pilot and (b) toxicology study animals. AADC staining of mid-brain revealed good correlation between infusate (gadolinium) signal in MRI and AAV2-hAADC expression (left and middle columns). AADC signal (brown) in SNpc and VTA that colocalized with endogenous tyrosine hydroxylase signal (blue, middle column). Although transgenic AADC in these nuclei was indistinguishable from endogenous AADC, AAV2-hAADC gene product was easily visible in SNpr when compared to naïve animal images. Higher magnification images show transgenic AADC staining in cells and fibers (right column). Scale bars: Left and middle columns: 1 cm; right column: 200 μm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4274790&req=5

fig3: AADC expression in the mid-brain of (a) pilot and (b) toxicology study animals. AADC staining of mid-brain revealed good correlation between infusate (gadolinium) signal in MRI and AAV2-hAADC expression (left and middle columns). AADC signal (brown) in SNpc and VTA that colocalized with endogenous tyrosine hydroxylase signal (blue, middle column). Although transgenic AADC in these nuclei was indistinguishable from endogenous AADC, AAV2-hAADC gene product was easily visible in SNpr when compared to naïve animal images. Higher magnification images show transgenic AADC staining in cells and fibers (right column). Scale bars: Left and middle columns: 1 cm; right column: 200 μm.
Mentions: Neurons in the SNpc and VTA express endogenous AADC that made difficult to distinguish transduced neurons from those not transduced in these nuclei. Nevertheless, the distribution and intensity of immunohistochemical AADC staining in the mid-brain of AAV2-hAADC-treated animals clearly showed increased AADC expression within the targeted area when compared to mid-brain staining in control animals (Figure 3a (pilot) and 3B (pivotal toxicology)). In some of the animals, transgenic hAADC signal was noted in the lateral SNpr, normally devoid of AADC, both in double chromogenic (Figure 3) and double immunofluorescent sections (Supplementary Figure S3). Histological sections in some of the animals revealed the cannula tract, thereby confirming optimal placement of the cannula and matching observed MRI tracer (Figure 2) in VTA and medial-lateral SNpc.

Bottom Line: As a result, patients suffer compromised development, particularly in motor function.The objective of this study was to assess the long-term safety and tolerability of bilateral AAV2-hAADC MRI-guided pressurized infusion into the mid-brain of non-human primates.Our data indicate that effective mid-brain transduction was achieved without untoward effects.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurological Surgery, University of California San Francisco, San Francisco, CA, USA.

ABSTRACT

Aromatic L-amino acid decarboxylase (AADC) deficiency is a rare, autosomal-recessive neurological disorder caused by mutations in the DDC gene that leads to an inability to synthesize catecholamines and serotonin. As a result, patients suffer compromised development, particularly in motor function. A recent gene replacement clinical trial explored putaminal delivery of recombinant adeno-associated virus serotype 2 vector encoding human AADC (AAV2-hAADC) in AADC-deficient children. Unfortunately, patients presented only modest amelioration of motor symptoms, which authors acknowledged could be due to insufficient transduction of putamen. We hypothesize that, with the development of a highly accurate MRI-guided cannula placement technology, a more effective approach might be to target the affected mid-brain neurons directly. Transduction of AADC-deficient dopaminergic neurons in the substantia nigra and ventral tegmental area with locally infused AAV2-hAADC would be expected to lead to restoration of normal dopamine levels in affected children. The objective of this study was to assess the long-term safety and tolerability of bilateral AAV2-hAADC MRI-guided pressurized infusion into the mid-brain of non-human primates. Animals received either vehicle, low or high AAV2-hAADC vector dose and were euthanized 1, 3 or 9 months after surgery. Our data indicate that effective mid-brain transduction was achieved without untoward effects.

No MeSH data available.


Related in: MedlinePlus