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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

Axonal transport of AADC protein through the nigrostriatal pathway. Double immunohistochemical staining for TH (blue) and AADC (brown) in the striatum demonstrated the presence of the transgenic AADC in nigrostriatal terminals that widely covered both caudate and putamen nuclei. High-magnification images show the intensity of AADC staining in transduced fibers in AAV2-hAADC-treated animals compared to endogenous signal in PBS control group. Black squares indicate the area shown in higher magnification images. Notice the similar fiber density for both low and high AAV2-hAADC doses. Scale bar: 100 μm.
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fig4: Axonal transport of AADC protein through the nigrostriatal pathway. Double immunohistochemical staining for TH (blue) and AADC (brown) in the striatum demonstrated the presence of the transgenic AADC in nigrostriatal terminals that widely covered both caudate and putamen nuclei. High-magnification images show the intensity of AADC staining in transduced fibers in AAV2-hAADC-treated animals compared to endogenous signal in PBS control group. Black squares indicate the area shown in higher magnification images. Notice the similar fiber density for both low and high AAV2-hAADC doses. Scale bar: 100 μm.

Mentions: AADC immunohistochemical staining was semi-quantitatively analyzed by observers blind to the treatment groups. Coronal brain sections containing either the precommissural, commissural, postcommissural striatum, and other basal ganglia nuclei were included in the analysis of the striatal and off-target AADC transgene expression. Transduction of SNpc and VTA neurons resulted in the expression of hAADC in these neurons and the filling of neuronal cytoplasm with the hAADC protein. Thus, since those neurons project axons to the striatum, we detected increased AADC protein in caudate nucleus, putamen and nucleus accumbens in AAV2-hAADC animals compared to control group. Transgenic AADC expression in the striatum was robust, widely distributed and restricted to neuronal fibers (Figure 4) in both AAV2-hAADC-treated groups, regardless of vector dose or survival time. Four out of six animals in both low- and high-dose groups exhibited prominent AADC-immunoreactive (ir) fibers whereas the other two animals in each group presented fewer fibers, mainly in the most anterior sections examined (Supplementary Table S2). As expected, animals in the control group displayed no evidence of transgenic hAADC, with AADC-ir restricted to light staining consistent with endogenous expression (Figure 4 and Table 2). This was further confirmed with double immunofluorescent staining against TH and AADC in tissue sections containing striatum, where fluorescent intensity of AADC fibers was stronger in AAV2-hAADC-treated animals, regardless of vector dose (Supplementary Figure S3). With respect to nucleus accumbens, only two animals presented a few intense AADC-ir fibers in the core but none in the shell region. There was no significant effect of survival time among AAV2-hAADC or control groups, nor was there a significant vector dose effect on AAV2-hAADC-treated groups.


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)

Axonal transport of AADC protein through the nigrostriatal pathway. Double immunohistochemical staining for TH (blue) and AADC (brown) in the striatum demonstrated the presence of the transgenic AADC in nigrostriatal terminals that widely covered both caudate and putamen nuclei. High-magnification images show the intensity of AADC staining in transduced fibers in AAV2-hAADC-treated animals compared to endogenous signal in PBS control group. Black squares indicate the area shown in higher magnification images. Notice the similar fiber density for both low and high AAV2-hAADC doses. Scale bar: 100 μm.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

fig4: Axonal transport of AADC protein through the nigrostriatal pathway. Double immunohistochemical staining for TH (blue) and AADC (brown) in the striatum demonstrated the presence of the transgenic AADC in nigrostriatal terminals that widely covered both caudate and putamen nuclei. High-magnification images show the intensity of AADC staining in transduced fibers in AAV2-hAADC-treated animals compared to endogenous signal in PBS control group. Black squares indicate the area shown in higher magnification images. Notice the similar fiber density for both low and high AAV2-hAADC doses. Scale bar: 100 μm.
Mentions: AADC immunohistochemical staining was semi-quantitatively analyzed by observers blind to the treatment groups. Coronal brain sections containing either the precommissural, commissural, postcommissural striatum, and other basal ganglia nuclei were included in the analysis of the striatal and off-target AADC transgene expression. Transduction of SNpc and VTA neurons resulted in the expression of hAADC in these neurons and the filling of neuronal cytoplasm with the hAADC protein. Thus, since those neurons project axons to the striatum, we detected increased AADC protein in caudate nucleus, putamen and nucleus accumbens in AAV2-hAADC animals compared to control group. Transgenic AADC expression in the striatum was robust, widely distributed and restricted to neuronal fibers (Figure 4) in both AAV2-hAADC-treated groups, regardless of vector dose or survival time. Four out of six animals in both low- and high-dose groups exhibited prominent AADC-immunoreactive (ir) fibers whereas the other two animals in each group presented fewer fibers, mainly in the most anterior sections examined (Supplementary Table S2). As expected, animals in the control group displayed no evidence of transgenic hAADC, with AADC-ir restricted to light staining consistent with endogenous expression (Figure 4 and Table 2). This was further confirmed with double immunofluorescent staining against TH and AADC in tissue sections containing striatum, where fluorescent intensity of AADC fibers was stronger in AAV2-hAADC-treated animals, regardless of vector dose (Supplementary Figure S3). With respect to nucleus accumbens, only two animals presented a few intense AADC-ir fibers in the core but none in the shell region. There was no significant effect of survival time among AAV2-hAADC or control groups, nor was there a significant vector dose effect on AAV2-hAADC-treated groups.

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