Gene Transfer in Adeno-Associated Virus Seropositive Rhesus Macaques Following Rapamycin Treatment and Subcutaneous Delivery of AAV6, but Not Retargeted AAV6 Vectors
HUMAN GENE THERAPY
Authors: Stone, Daniel; Kenkel, Elizabeth J.; Loprieno, Michelle A.; Tanaka, Motoko; Feelixge, Harshana S. De Silva; Kumar, Arjun J.; Stensland, Laurence; Obenza, Willimark M.; Wangari, Solomon; Ahrens, Chul Y.; Murnane, Robert D.; Peterson, Christopher W.; Kiem, Hans-Peter; Huang, Meei-Li; Aubert, Martine; Hu, Shiu-Lok; Jerome, Keith R.
Abstract
Adeno-associated virus (AAV) vectors such as AAV6, which shows tropism for primary human CD4(+) T cells in vitro, are being explored for delivery of anti-HIV therapeutic modalities in vivo. However, pre-existing immunity and sequestration in nontarget organs can significantly hinder their performance. To overcome these challenges, we investigated whether immunosuppression would allow gene delivery by AAV6 or targeted AAV6 derivatives in seropositive rhesus macaques. Animals were immune suppressed with rapamycin before intravenous (IV) or subcutaneous (SC) delivery of AAV, and we monitored vector biodistribution, gene transfer, and safety. Macaques received phosphate-buffered saline, AAV6 alone, or an equal dose of AAV6 and an AAV6-55.2 vector retargeted to CD4 through a direct ankyrin repeat protein (DARPin). AAV6 and AAV6-55.2 vector genomes were found in peripheral blood mononuclear cells and most organs up to 28 days postadministration, with the highest levels seen in liver, spleen, lymph nodes (LNs), and muscle, suggesting that retargeting did not prevent vector sequestration. Despite vector genome detection, gene expression from AAV6-55.2 was not detected in any tissue. SC injection of AAV6 facilitated efficient gene expression in muscle adjacent to the injection site, plus low-level gene expression in spleen, LNs, and liver, whereas gene expression following IV injection of AAV6 was predominantly seen in the spleen. AAV vectors were well tolerated, although elevated liver enzymes were detected in three of four AAV-treated animals 14 days after rapamycin withdrawal. One SC-injected animal had muscle inflammation proximal to the injection site, plus detectable T cell responses against transgene and AAV6 capsid at study finish. Overall, our data suggest that rapamycin treatment may offer a possible strategy to express anti-HIV therapeutics such as broadly neutralizing antibodies from muscle. This study provides important safety and efficacy data that will aid study design for future anti-HIV gene therapies.
Interventions for children with neurocognitive impairments in resource-limited settings: A systematic review
CHILDREN AND YOUTH SERVICES REVIEW
Authors: Van Pelt, Amelia E.; Lipow, Matthew, I; Scott, J. Cobb; Lowenthal, Elizabeth D.
Abstract
Many children and adolescents around the world suffer from neurocognitive deficits due to chronic disorders, such as Human Immunodeficiency Virus (HIV) and malaria. Resource-limited settings exacerbate the risk of negative cognitive outcomes due to high prevalence of associated disorders, poverty, and limited access to interventions. Current literature does not provide consensus regarding the efficacy of interventions to support children with cognitive impairments in low-resource settings. This research aimed to identify and evaluate interventions for youth with neurocognitive deficits in resource-limited settings. A systematic review of peer-reviewed literature was conducted within five databases (PubMed, Web of Science, CINAHL, PsycInfo, and WHO Index Medicus). Cognitive impairment was broadly defined to be inclusive of aspects of intellectual and cognitive functioning (e.g., working memory, attention, executive function). The income status of the country or countries in which each study was located was determined according to World Bank Income Status. Studies conducted in countries classified as low- or middle-income were included. Since low-resource areas exist within high-income countries, the resource availability within study settings in high-income countries was systematically evaluated for inclusion. The search yielded 19 articles that met all inclusion criteria. Interventions included strategies involving caregiver training, computerized and non-computerized cognitive training, physical activity, and nutritional supplementation. Interventions were administered in medical facilities, educational facilities, or the home. The majority of the interventions targeted the domains of memory and attention. Overall, the efficacy of interventions was inconsistent. Further, results indicated that the relationship between cognitive improvement and intervention types was not consistent across cognitive domains. However, when evaluating studies on an individual basis, some strategies demonstrated clinically- and statistically-significant improvement in cognitive function among specific groups of children. The low article yield highlights that few researchers have evaluated pediatric cognitive support interventions in low-resource contexts. This review suggests support strategies that should be considered for future studies as neurocognitive screening capacity improves in resource-limited settings.