Induced islet neogenesis therapy in vivo

描述（由申请人提供）：尽管口服降糖药促进胰岛素分泌或减少胰岛素抵抗的发展，不同形式的胰岛素具有广泛不同的作用时间，以及胰岛移植方案的显著改进，但胰岛素缺乏性糖尿病的治疗仍然令人不满意。实验性基因疗法正在被探索，作为一种可能的选择，以改善治疗或潜在地“治愈”这种疾病。最近由首席研究员开发的一种很有前景的基因治疗策略是通过将胰岛特异性转录因子传递到糖尿病小鼠的肝脏来诱导胰岛新生。我们使用辅助依赖腺病毒（HDAd）将转录因子NeuroD/Beta2 （ND/B2）和胰岛生长因子betaculin （Btc）传递到链脲佐菌素糖尿病小鼠的肝脏。作为对治疗的反应，小鼠在肝脏中形成了新的胰岛，并在葡萄糖耐量试验（GTT）中达到了正常的血糖和胰岛素水平。这种治疗逆转了这些老鼠的糖尿病，持续了四个多月，也就是实验的持续时间。观察到该治疗的毒性可忽略不计。在这个R21应用程序中，我们建议在非人类灵长类动物模型中探索使用类似的策略来治疗糖尿病。有两个具体目标：1。利用链脲佐菌素（STZ）治疗狒狒建立胰岛素缺乏型糖尿病模型。2. 采用球囊导管为基础的方法，将含有胰岛特异性转录因子Neurogenin 3 （Ngn3）和胰岛生长因子等的HDAd注入stz诱导的糖尿病狒狒肝脏，诱导胰岛新生，达到逆转狒狒糖尿病的目的。初步实验表明，Ngn3比ND/ 2的效果更好。在狒狒身上进行的其他试点实验使我们能够开发出基于球囊导管的方案，将高剂量的hdad直接输送到肝脏，而不会产生明显的全身传播或毒性。该方案将避免在系统给药时观察到的hdd的实质性毒性。这些目标是基于有充分文件证明的初步实验。如果这种治疗策略能改善狒狒的糖尿病，而且没有明显的毒副作用，那么它将是一个重要的原理验证实验，为将来可能的临床试验铺平道路。

DESCRIPTION (provided by applicant): Despite the development of oral hypoglycemic agents that boost insulin secretion or reduce insulin resistance, and of different forms of insulin with widely varying durations of action, and the advent of a markedly improved protocol for islet transplantation, the treatment of insulin-deficient diabetes remains unsatisfactory. Experimental gene therapy is being explored as a possible option for an improved treatment or potentially a "cure" for the disease. A promising gene therapy strategy that was recently developed by the Principal Investigator is that of induced islet neogenesis by the delivery of islet-specific transcription factor to the liver of diabetic mice. We used a helper-dependent adenovirus (HDAd) to deliver a transcription factor, NeuroD/Beta2 (ND/B2), and an islet growth factor, betacellulin (Btc), to the liver of streptozotocin diabetic mice. In response to the treatment, the mice formed new pancreatic islets in the liver and developed normal blood glucose and insulin levels during a glucose tolerance test (GTT). The treatment reversed the diabetes of these mice for over four months, the duration of the experiment. There was negligible toxicity observed for the treatment. In this R21 application we propose to explore the use of a similar strategy to treat diabetes in a non-human primate model. There are 2 specific aims: 1. to establish an insulin-deficient diabetes model in baboons using streptozotocin (STZ) treatment. 2. To use a balloon catheter-based method to deliver into the liver of STZ-induced diabetic baboons HDAd containing the islet-specific transcription Neurogenin 3 (Ngn3) and the islet growth factor Etc to induce islet neogenesis with the objective of reversing the diabetes of baboons. Preliminary experiments show that Ngn3 produces even better results than ND/?2. Other pilot experiments in baboons have allowed us to develop the balloon catheter-based protocol to deliver HDAds at a high dose directly to the liver without significant systemic dissemination or toxicity. This protocol would circumvent the substantial toxicity of HDAds that is observed when the vector is administered systemically. These aims are based on well documented preliminary experiments. If the treatment strategy ameliorates diabetes in baboons without significant toxic side effects, then it will be an important proof-of-principle experiment that will pave the way for possible clinical trials in the future.