Myocarditis following adeno-associated viral gene expression of human soluble TNF receptor (TNFRII-Fc) in baboon hearts

Abstract

Sequestration of tumor necrosis factor-a (TNFa) by TNFreceptor immunoglobulin G (IgG)-Fc fusion proteins can limit heart failure progression in rodent models. In this study we directly injected an adeno-associated viruses (AAV)-2 construct encoding a human TNF receptor II IgG-Fc fusion protein (AAV-TNFRII-Fc) into healthy baboon hearts and assessed virally encoded gene expression and clinical response. Adult baboons received direct cardiac injections of AAV-TNFRII-Fc (B5 Â 10 12 viral/genomes/baboon) or an equivalent dose of AAV-2 empty capsids, and were analyzed after 5 or 12 weeks. Viral genomes were restricted to the myocardium, and routine analyses (blood cell counts, clinical chemistries) remained unremarkable. Echocardiograms were unchanged but electrocardiograms revealed marked ST-and T-wave changes consistent with myocarditis only in baboons receiving AAV-TNFRII-Fc. TNFRII serum levels peaked at B3 times the baseline levels at 1-2 weeks postinjection and subsequently declined to baseline levels. TNFRII-Fc protein and transcripts were detected in the heart at harvest. After AAV injection, anti-AAV-2 antibody levels increased in all baboons, while anti-TNFRII-Fc could not be detected. Baboons that received AAV-TNFRII-Fc developed myocardial infiltrates including CD8+ cells. Thus, a cellular immune response to cardiac delivery of AAV encoding foreign proteins may be an important consideration for AAV-based cardiac gene therapy.

DNA delivery to ‘ex vivo’ human liver segments

“…2,[8][9][10] However, the systemic perturbation resulting from hydrodynamic injection remains a serious limitation for clinical application, as it can lead to circulatory collapse and even death. To avoid this adverse effect, we have described a retrograde cathetermediated gene delivery procedure 5 with the aim of locally reproducing the intrahepatic conditions mediated by tail vein hydrodynamic injection.…”

Cardiac Gene Transfer of Short Hairpin RNA Directed Against Phospholamban Effectively Knocks Down Gene Expression but Causes Cellular Toxicity in Canines

“…Studies using virus-mediated transfer of shRNA directed against PLB in cardiomyocyte culture have demonstrated that it is an effective method for both knocking down PLB expression and modulating calcium handling (Fechner et al, 2007;Andino et al, 2008), and one study in a rat model of HF demonstrated that AAV-mediated transfer of shRNA is effective in restoring cardiac function and geometry (Suckau et al, 2009). In addition, because the gene product in this case would be a functional RNA and not a mutant protein (dnPLB), this strategy would avoid the potential of evoking a T cell response directed against cells expressing the transgene, as has been reported after AAV-mediated cardiac gene transfer of a modified, soluble TNF receptor in baboons (McTiernan et al, 2007). This is an important consideration when considering large animal and clinical trials.…”

Cardiac gene therapy in large animals: bridge from bench to bedside

“…Intramyocardial delivery of human soluble tumor necrosis factor-a receptor II-Fc fusion protein was performed in intact non-human primates; however, it was associated with local myocarditis at the injection sites. 94 A unique approach is the gene delivery of neuronal nitric oxide synthase to cardiac vagus in pigs. 95 Because enhanced vagal function was observed after the gene delivery, additional positive data in a heart failure model may hold more promise.…”