Quantitative Whole-Body Imaging of I-124-Labeled Adeno-Associated Viral Vector Biodistribution in Nonhuman Primates.
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ABSTRACT:
SUBMITTER: Ballon DJ
PROVIDER: S-EPMC7769048 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:We recently developed the radiotracer 4-[(3-iodophenyl)amino]-7-(2-[2-{2-(2-[2-{2-((18)F-fluoroethoxy)-ethoxy}-ethoxy]-ethoxy)-ethoxy}-ethoxy]-quinazoline-6-yl-acrylamide) ((18)F-PEG(6)-IPQA) for noninvasive detection of active mutant epidermal growth factor receptor kinase-expressing non-small cell lung cancer xenografts in rodents. In this study, we determined the pharmacokinetics, biodistribution, metabolism, and radiation dosimetry of (18)F-PEG(6)-IPQA in nonhuman primates.Six rhesus macaques were injected intravenously with 141 ± 59.2 MBq of (18)F-PEG(6)-IPQA, and dynamic PET/CT images covering the thoracoabdominal area were acquired for 30 min, followed by whole-body static images at 60, 90, 120, and 180 min. Blood samples were obtained from each animal at several time points after radiotracer administration. Radiolabeled metabolites in blood and urine were analyzed using high-performance liquid chromatography. The (18)F-PEG(6)-IPQA pharmacokinetic and radiation dosimetry estimates were determined using volume-of-interest analysis of PET/CT image datasets and blood and urine time-activity data.(18)F-PEG(6)-IPQA exhibited rapid redistribution and was excreted via the hepatobiliary and urinary systems. (18)F-PEG(6) was the major radioactive metabolite. The critical organ was the gallbladder, with an average radiation-absorbed dose of 0.394 mSv/MBq. The other key organs with high radiation doses were the kidneys (0.0830 mSv/MBq), upper large intestine wall (0.0267 mSv/MBq), small intestine (0.0816 mSv/MBq), and liver (0.0429 mSv/MBq). Lung tissue exhibited low uptake of (18)F-PEG(6)-IPQA due to the low affinity of this radiotracer to wild-type epidermal growth factor receptor kinase. The effective dose was 0.0165 mSv/MBq. No evidence of acute cardiotoxicity or of acute or delayed systemic toxicity was observed. On the basis of our estimates, diagnostic dosages of (18)F-PEG(6)-IPQA up to 128 MBq (3.47 mCi) per injection should be safe for administration in the initial cohort of human patients in phase I clinical PET studies.The whole-body and individual organ radiation dosimetry characteristics and pharmacologic safety of diagnostic dosages of (18)F-PEG(6)-IPQA in nonhuman primates indicate that this radiotracer should be acceptable for PET/CT studies in human patients.
| S-EPMC4013275 | biostudies-literature
Project description:A combination treatment of AAV2-hAADC with oral levodopa is a novel therapeutic approach that is being developed for late-stage Parkinson's disease. Biodistribution of AAV2-hAADC was assessed over a wide range of vector dose in 12 monkeys with parkinsonian syndrome, 6 months after intraputamenal infusion. Quantitative PCR (Q-PCR) from all the major neuroanatomical regions of the brain indicated a dose-dependent increase in vector DNA, with 99% being detected in the target site and other basal ganglia tissues. Within these tissues, the distribution varied widely between the putamen (PT) and the globus pallidus, and this was attributed to differences in vector transport. Q-PCR and immunocytochemistry were consistent with results reported earlier for various measures of transgene expression including aromatic L-amino acid decarboxylase (AADC) activity assays, behavioral response, and in vivo imaging with positron emission tomography (PET). Outside of the brain, trace amounts of vector DNA were detected in the spleens of animals in the two highest dose groups, but not in any other peripheral tissue, blood, or cerebrospinal fluid. Some increase in neutralizing antibody titers to adeno-associated virus type-2 (AAV2) capsid protein was observed in monkeys that received high doses of AAV2-hAADC or control AAV2-GFP. This study further validates convection-enhanced delivery (CED) as the preferred method of viral vector delivery to the brain, and supports a Phase I clinical testing of AAV2-hAADC in humans with Parkinson's disease.
| S-EPMC2766605 | biostudies-literature
Project description:Gene therapy is a promising approach in the treatment of inherited and common complex disorders of the retina. Preclinical and clinical studies have validated the use of adeno-associated viral vectors (AAV) as a safe and efficient delivery vehicle for gene transfer. Retinal pigment epithelium and rods-and to a lesser extent, cone photoreceptors-can be efficiently targeted with AAV. Other retinal cell types however are more challenging targets. The aim of this study was to characterize the transduction profile and efficiency of in silico designed, synthetic Anc80 AAVs for retinal gene transfer. Three Anc80 variants were evaluated for retinal targeting in mice and primates following subretinal delivery. In the murine retina Anc80L65 demonstrated high level of retinal pigment epithelium and photoreceptor targeting with comparable cone photoreceptor affinity compared to other AAVs. Remarkably, Anc80L65 enhanced transduction kinetics with visible expression as early as day 1 and steady state mRNA levels at day 3. Inner retinal tropism of Anc80 variants demonstrated distinct transduction patterns of Müller glia, retinal ganglion cells and inner nuclear layer neurons. Finally, murine findings with Anc80L65 qualitatively translated to the Rhesus macaque in terms of cell targets, levels and onset of expression. Our findings support the use of Anc80L65 for therapeutic subretinal gene delivery.
| S-EPMC6066192 | biostudies-literature
Project description:Limited packaging capacity has hampered adeno-associated virus (AAV)-mediated gene therapy for many common genetic diseases such as cystic fibrosis (CF) and Duchenne muscular dystrophy (DMD). Trans-splicing AAV (tsAAV) vectors double AAV packaging capacity but their transduction efficiency has been too low to be useful. We have recently overcome this hurdle by rational vector design. We have shown that a pair of optimized mini-dystrophin tsAAV vectors can reach the same transduction efficiency as that of a single AAV vector after local injection in dystrophic muscle. However, global gene transfer is required to treat diseases like DMD. To test whether systemic delivery can be achieved with tsAAV vectors, we generated a set of optimized alkaline phosphatase (AP) tsAAV vectors. We delivered AAV serotype 9 pseudotyped AP tsAAV intravenously to newborn mice. Six weeks later, we observed high-level transduction in all body skeletal muscle and the heart, the tissues that are affected in DMD. We also detected efficient transduction in the lung, the primary organ affected in CF. Our results provide the first evidence of whole-body transduction with tsAAV vectors and further raise the hope of tsAAV gene therapy for DMD and CF.
| S-EPMC2581720 | biostudies-literature
Project description:Lenadogene nolparvovec (Lumevoq) gene therapy was developed to treat Leber hereditary optic neuropathy (LHON) caused by the m.11778G > A in MT-ND4 that affects complex I of the mitochondrial respiratory chain. Lenadogene nolparvovec is a replication-defective, single-stranded DNA recombinant adeno-associated virus vector 2 serotype 2, containing a codon-optimized complementary DNA encoding the human wild-type MT-ND4 subunit protein. Lenadogene nolparvovec was administered by unilateral intravitreal injection in MT-ND4 LHON patients in two randomized, double-masked, and sham-controlled phase III clinical trials (REVERSE and RESCUE), resulting in bilateral improvement of visual acuity. These and other earlier results suggest that lenadogene nolparvovec may travel from the treated to the untreated eye. To investigate this possibility further, lenadogene nolparvovec was unilaterally injected into the vitreous body of the right eye of healthy, nonhuman primates. Viral vector DNA was quantifiable in all eye and optic nerve tissues of the injected eye and was detected at lower levels in some tissues of the contralateral, noninjected eye, and optic projections, at 3 and 6 months after injection. The results suggest that lenadogene nolparvovec transfers from the injected to the noninjected eye, thus providing a potential explanation for the bilateral improvement of visual function observed in the LHON patients.
| S-EPMC8526752 | biostudies-literature
Project description:Gene delivery vectors based on adeno-associated viruses (AAV) have exhibited promise in both preclinical disease models and human clinical trials for numerous disease targets, including the retinal degenerative disorders Leber's congenital amaurosis and choroideremia. One general challenge for AAV is that preexisting immunity, as well as subsequent development of immunity following vector administration, can severely inhibit systemic AAV vector gene delivery. However, the role of neutralizing antibodies (NABs) in AAV transduction of tissues considered to be immune privileged, such as the eye, is unclear in large animals. Intravitreal AAV administration allows for broad retinal delivery, but is more susceptible to interactions with the immune system than subretinal administration. To assess the effects of systemic anti-AAV antibody levels on intravitreal gene delivery, we quantified the anti-AAV antibodies present in sera from non-human primates before and after intravitreal injections with various AAV capsids. Analysis showed that intravitreal administration resulted in an increase in anti-AAV antibodies regardless of the capsid serotype, transgene or dosage of virus injected. For monkeys injected with wild-type AAV2 and/or an AAV2 mutant, the variable that most significantly affected the production of anti-AAV2 antibodies was the amount of virus delivered. In addition, post-injection antibody titers were highest against the serotype administered, but the antibodies were also cross-reactive against other AAV serotypes. Furthermore, NAB levels in serum correlated with those in vitreal fluid, demonstrating both that this route of administration exposes AAV capsid epitopes to the adaptive immune system and that serum measurements are predictive of vitreous fluid NAB titers. Moreover, the presence of preexisting NAB titers in the serum of monkeys correlated strongly (R=0.76) with weak, decaying or no transgene expression following intravitreal administration of AAV. Investigating anti-AAV antibody development will aid in understanding the interactions between gene therapy vectors and the immune system during ocular administration and can form a basis for future clinical studies applying intravitreal gene delivery.
| S-EPMC4393652 | biostudies-literature
Project description:Neurotropic adeno-associated virus (AAV) serotypes such as AAV9 have been demonstrated to transduce spinal alpha motor neurons when administered intravenously (i.v.) at high doses. This observation led to the recent successful application of i.v. AAV9 delivery to treat infants with spinal muscular atrophy, an inherited deficiency of the survival of motor neuron (SMN) protein characterized by selective death of lower motor neurons. To evaluate the efficiency of motor neuron transduction with an AAV9 variant (AAVhu68) using this approach, three juvenile nonhuman primates (NHPs; aged 14 months) and three piglets (aged 7-30 days) were treated with an i.v. injection of an AAVhu68 vector carrying a human SMN transgene at a dose similar to that employed in the spinal muscular atrophy clinical trial. Administration of 2?×?1014 genome copies per kilogram of body weight resulted in widespread transduction of spinal motor neurons in both species. However, severe toxicity occurred in both NHPs and piglets. All three NHPs exhibited marked transaminase elevations. In two NHPs, the transaminase elevations resolved without clinical sequelae, while one NHP developed acute liver failure and shock and was euthanized 4 days after vector injection. Degeneration of dorsal root ganglia sensory neurons was also observed, although NHPs exhibited no clinically apparent sensory deficits. There was no correlation between clinical findings and T-cell responses to the vector capsid or transgene product in NHPs. Piglets demonstrated no evidence of hepatic toxicity, but within 14 days of vector injection, all three animals exhibited proprioceptive deficits and ataxia, which profoundly impaired ambulation and necessitated euthanasia. These clinical findings correlated with more severe dorsal root ganglia sensory neuron lesions than those observed in NHPs. The liver and sensory neuron findings appear to be a direct consequence of AAV transduction independent of an immune response to the capsid or transgene product. The present results and those of another recent study utilizing a different AAV9 variant and transgene indicate that systemic and sensory neuron toxicity may be general properties of i.v. delivery of AAV vectors at high doses, irrespective of the capsid serotype or transgene. Preclinical and clinical studies involving high systemic doses of AAV vectors should include careful monitoring for similar toxicities.
| S-EPMC5865262 | biostudies-literature
Project description:Multiple system atrophy (MSA) is a horrible and unrelenting neurodegenerative disorder with an uncertain etiology and pathophysiology. MSA is a unique proteinopathy in which alpha-synuclein (α-syn) accumulates preferentially in oligodendroglia rather than neurons. Glial cytoplasmic inclusions (GCIs) of α-syn are thought to elicit changes in oligodendrocyte function, such as reduced neurotrophic support and demyelination, leading to neurodegeneration. To date, only a murine model using one of three promoters exist to study this disease. We sought to develop novel rat and nonhuman primate (NHP) models of MSA by overexpressing α-syn in oligodendroglia using a novel oligotrophic adeno-associated virus (AAV) vector, Olig001. To establish tropism, rats received intrastriatal injections of Olig001 expressing GFP. Histological analysis showed widespread expression of GFP throughout the striatum and corpus callosum with >95% of GFP+ cells co-localizing with oligodendroglia and little to no expression in neurons or astrocytes. We next tested the efficacy of this vector in rhesus macaques with intrastriatal injections of Olig001 expressing GFP. As in rats, we observed a large number of GFP+ cells in gray matter and white matter tracts of the striatum and the corpus callosum, with 90-94% of GFP+ cells co-localizing with an oligodendroglial marker. To evaluate the potential of our vector to elicit MSA-like pathology in NHPs, we injected rhesus macaques intrastriatally with Olig001 expressing the α-syn transgene. Histological analysis 3-months after injection demonstrated widespread α-syn expression throughout the striatum as determined by LB509 and phosphorylated serine-129 α-syn immunoreactivity, all of which displayed as tropism similar to that seen with GFP. As in MSA, Olig001-α-syn GCIs in our model were resistant to proteinase K digestion and caused microglial activation. Critically, demyelination was observed in the white matter tracts of the corpus callosum and striatum of Olig001-α-syn but not Olig001-GFP injected animals, similar to the human disease. These data support the concept that this vector can provide novel rodent and nonhuman primate models of MSA.
| S-EPMC5473003 | biostudies-literature
Project description:Discovery of novel drug delivery systems to the brain remains a key task for successful treatment of neurodegenerative disorders. Herein, the biodistribution of immunocyte-based carriers, peripheral blood mononuclear cells (PBMCs), and monocyte-derived EVs are investigated in adult rhesus macaques using longitudinal PET/MRI imaging. 64 Cu-labeled drug carriers are introduced via different routes of administration: intraperitoneal (IP), intravenous (IV), or intrathecal (IT) injection. Whole body PET/MRI (or PET/CT) images are acquired at 1, 24, and 48 h post injection of 64 Cu-labeled drug carriers, and standardized uptake values (SUVmean and SUVmax ) in the main organs are estimated. The brain retention for both types of carriers increases based on route of administration: IP < IV < IT. Importantly, a single IT injection of PBMCs produces higher brain retention compared to IT injection of EVs. In contrast, EVs show superior brain accumulation compared to the cells when administered via IP and IV routes, respectively. Finally, a comprehensive chemistry panel of blood samples demonstrates no cytotoxic effects of either carrier. Overall, living cells and EVs have a great potential to be used for drug delivery to the brain. When identifying the ideal drug carrier, the route of administration could make big differences in CNS drug delivery.
| S-EPMC8825682 | biostudies-literature
Project description:ObjectivesPeripheral benzodiazepine receptors (PBRs) are upregulated on activated microglia and are thereby biomarkers of neuroinflammation. We developed a PET ligand with an aryloxyanilide structure, [O-methyl-(11)C]N-acetyl-N-(2-methoxybenzyl)-2-phenoxy-5-pyridinamine ([(11)C]PBR28), to image PBRs. The objectives of the current study were to evaluate kinetics of brain uptake, and the influence of the peripheral binding on the arterial input function in rhesus monkey.MethodsBrain (baseline: n=6, blocking: n=1) and whole-body PET imaging (baseline: n=3, blocking: n=1) of [(11)C]PBR28 were performed with the measurement of radiometabolite-corrected arterial input function in all brain and two whole body scans.ResultsSaturating doses of nonradioactive PBR ligands markedly increased [(11)C]PBR28 in plasma (approximately 400% increase) and brain (approximately 200%) at 2 min by displacing radioligand from PBRs in peripheral organs. Brain uptake of radioactivity peaked in baseline scans at approximately 40 min after injection of [(11)C]PBR28 and was high (approximately 300% standardized uptake value). The images showed no receptor-free region that could be used for reference tissue analysis. Thus, quantitation of receptor density required measurement of parent radioligand in arterial plasma. Nondisplaceable uptake was estimated from the blocked scans and was only approximately 5% of total distribution volume measured under baseline conditions. Distribution volume of [(11)C]PBR28 was stably determined within 110 min of scanning.ConclusionsRegional brain uptake of [(11)C]PBR28 in monkey could be quantified as a value proportional to the density of receptors--namely, as equilibrium distribution volume. [(11)C]PBR28 had high levels of specific binding in brain and should provide a sensitive measure of changes in PBRs.
| S-EPMC2275117 | biostudies-literature