McCormack, W.M. Jr. et al. Helper-dependent adenoviral gene therapy mediates long-term correction of the clotting defect in the canine hemophilia A model. J. Thromb. Haemost. 4, 1218-1225

Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA.
Journal of Thrombosis and Haemostasis (Impact Factor: 5.72). 07/2006; 4(6):1218-25. DOI: 10.1111/j.1538-7836.2006.01901.x
Source: PubMed


Adenoviral vector-mediated gene therapy might have potential for long-term correction of the monogenic disease hemophilia A.
In this study, we tested the efficacy of administering a helper-dependent adenoviral vector (HDV) designed for maximal liver-restricted canine factor VIII (cFVIII) expression on three out-bred hemophilia A dogs.
Three FVIII-deficient animals from the University of North Carolina colony were injected with 1 x 10(12) (Dog A), and 3 x 10(12) (Dog B and C) vp kg(-1) helper-dependent adenoviral vector, and we performed systematic analysis of toxicity, persistence of therapeutic gene expression, and molecular analysis of gene transfer.
We observed acute dose-dependent elevation in liver enzymes and thrombocytopenia after injection, although both were transient and resolved within 2 weeks. The whole blood clotting time (WBCT), plasma FVIII concentration, FVIII activity, and activated partial thromboplastin time in all animals improved significantly after treatment, and two animals receiving a higher dose reached near normal WBCT with low-level FVIII activity until terminal sacrifice at 3 months, and 2 years. Importantly, the treated dogs suffered no bleeding events after injection. Moreover, we observed persistent vector-specific DNA and RNA in liver tissue collected from one high-dose animal at days 18 and 79, and could not detect the formation of inhibitory antibodies.
Although vector-associated toxicity remains an obstacle, a single injection of HDV led to long-term transgene expression and vector persistence in two FVIII-deficient animals with conversion of their severe phenotype to a moderate one.

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    • "Sarkar et al believed that gene therapy duration in the dog with AAV8 containing FVIII have prolonged up to two years (Sarkar et al., 2006). Durable gene therapy based on AAV containing FVIII have also been reported by McCormack and colleagues (McCormack et al., 2006). Shi and colleagues findings suggest that targeted FVIII gene expression by platelets specific promoter is effective in the treatment of hemophilia A (Shi et al., 2006). "
    Targets in Gene Therapy, 08/2011; , ISBN: 978-953-307-540-2
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    • "The use of dogs can be explained by the fact that the dog offers a variety of spontaneous and experimental models of hematologic diseases. Recent examples are the use of canine hemophilia A [2] and B models [3,4], and the Canine Leukocyte Adhesion Deficiency model (CLAD) [5,6] in gene therapy experiments [2-8], and pharmacological experiments in leukopenic dogs [7] and in dogs with CLAD [8]. The larger size of dogs compared to small rodent models allows similar surgical procedures in humans as in dogs, and permits in most cases adequate acquisition of diagnostic samples. "
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    ABSTRACT: The dog is frequently used as a model for hematologic human diseases. In this study the suitability of nine potential reference genes for quantitative RT-PCR studies in canine whole blood was investigated. The expression of these genes was measured in whole blood samples of 263 individual dogs, representing 73 different breeds and a group of 40 mixed breed dogs, categorized into healthy dogs and dogs with internal and hematological diseases, and dogs that underwent a surgical procedure. GeNorm analysis revealed that a combination of 5 to 6 of the most stably expressed genes constituted a stable normalizing factor. Evaluation of the expression revealed different ranking of reference genes in Normfinder and GeNorm. The disease category and the white blood cell count significantly affected reference gene expression. The discrepancy between the ranking of reference genes in this study by Normfinder and Genorm can be explained by differences between the experimental groups such as "disease category" and "WBC count". This stresses the importance of assessing the expression stability of potential reference genes for gene experiments in canine whole blood anew for each specific experimental condition.
    BMC Research Notes 02/2011; 4:36. DOI:10.1186/1756-0500-4-36
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    • "Following the infection of 293 Cre cells, the packaging signal is excised from the helper virus genome by Cre-mediated site-specific recombination between the two loxP sites, and this precludes the packaging of the helper virus (Figure 2). Further improvements to this system have been made, which has permitted large scale manufacture of high quality HDAd with extremely low levels of helper virus contamination [33] for large animal preclinical studies [34–39]. Indeed, using this improved system [33], cGMP grade HDAd has been manufactured to treat patients with anemia with very encouraging results [159]. "
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    ABSTRACT: Recombinant Adenoviral vectors represent one of the best gene transfer platforms due to their ability to efficiently transduce a wide range of quiescent and proliferating cell types from various tissues and species. The activation of an adaptive immune response against the transduced cells is one of the major drawbacks of first generation Adenovirus vectors and has been overcome by the latest generation of recombinant Adenovirus, the Helper-Dependent Adenoviral (HDAd) vectors. HDAds have innovative features including the complete absence of viral coding sequences and the ability to mediate high level transgene expression with negligible chronic toxicity. This review summarizes the many aspects of HDAd biology and structure with a major focus on in vivo gene therapy application and with an emphasis on the unsolved issues that these vectors still presents toward clinical application.
    Viruses 09/2010; 2(9):1886-917. DOI:10.3390/v2091886 · 3.35 Impact Factor
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