Thulé Peter M, Campbell Adam G, Jia Dingwu, Lin Yulin, You Shou, Paveglio Sara, Olson Darin E, Kozlowski Miroslaw
Section Endocrinology and Metabolism, Atlanta VA Medical Center, Decatur, GA, USA.
Division of Endocrinology, Metabolism, & Lipids, Emory University School of Medicine, Emory University, Decatur, GA, USA.
J Gene Med. 2015 Aug-Sep;17(8-9):141-52. doi: 10.1002/jgm.2835.
Insulin self-administration is burdensome and can produce dangerous hypoglycemia. Insulin gene therapy may improve and simplify the treatment of diabetes mellitus. In rats, metabolically responsive hepatic insulin gene therapy (HIGT) delivered by adenovirus normalizes random blood sugars but with a limited duration. To prolong glycemic control, we delivered a metabolically regulated insulin transgene by adeno-associated virus (AAV).
We administered increasing doses of self-complementary (SC), pseudotyped AAV8 expressing the (GlRE)3 BP1-2xfur insulin transgene to streptozotocin-diabetic CD-1 mice, and monitored blood sugar and body weight. We also compared responses to intraperitoneal glucose and chow withdrawal, assessed for viral genomes in liver by Southern blotting, and measured hepatic glycogen.
Glucose lowering required the combination of SC genomes and AAV capsid pseudotyping. HIGT controlled glycemia in diabetic mice (DM) for > 1 year. However, glycemic responses were variable. Approximately 30% of mice succumbed to hypoglycemia, and approximately 30% of mice again became hyperglycemic. During an intraperitoneal glucose tolerance test, blood sugars declined to normal within 180 min in HIGT-treated DM compared to 90 min in control mice. Hypoglycemia was common among HIGT-treated mice during a 24-h fast. However, HIGT mice lost less weight than either diabetic or nondiabetic controls as a result of increased water intake. HIGT treatment reduced the hepatic glycogen content of fed mice.
Our studies demonstrate the possibility for long-term glycemic correction following AAV-mediated HIGT in mice. However, the dose-response relationship is irregular, and metabolic responsiveness may be less than that observed in rats.
胰岛素自我给药负担重，且可能导致危险的低血糖。胰岛素基因疗法可能改善并简化糖尿病的治疗。在大鼠中，腺病毒介导的代谢反应性肝胰岛素基因疗法（HIGT）可使随机血糖正常化，但持续时间有限。为延长血糖控制时间，我们通过腺相关病毒（AAV）递送了一种代谢调节的胰岛素转基因。
我们向链脲佐菌素诱导的糖尿病CD-1小鼠给予递增剂量的表达（GlRE）3 BP1-2xfur胰岛素转基因的自我互补（SC）、假型化AAV8，并监测血糖和体重。我们还比较了对腹腔内葡萄糖和禁食的反应，通过Southern印迹法评估肝脏中的病毒基因组，并测量肝糖原。
血糖降低需要SC基因组和AAV衣壳假型化的联合作用。HIGT使糖尿病小鼠（DM）的血糖得到控制超过1年。然而，血糖反应存在差异。约30%的小鼠死于低血糖，约30%的小鼠再次出现高血糖。在腹腔内葡萄糖耐量试验中，HIGT治疗的DM小鼠血糖在180分钟内降至正常，而对照小鼠为90分钟。在24小时禁食期间，HIGT治疗的小鼠中低血糖很常见。然而，由于水摄入量增加，HIGT小鼠体重减轻比糖尿病或非糖尿病对照小鼠少。HIGT治疗降低了喂食小鼠的肝糖原含量。
我们的研究证明了AAV介导的小鼠HIGT后长期血糖纠正的可能性。然而，剂量反应关系不规则，代谢反应性可能低于在大鼠中观察到的情况。
