Tiernan Aubrey R, Thulé Peter M, Sambanis Athanassios
1 School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA. 2 Section Endocrinology & Metabolism, Atlanta VA Medical Center, Division of Endocrinology, Lipids, & Diabetes, Emory University School of Medicine, Atlanta, GA. 3 Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA. 4 Address correspondence to: Athanassios Sambanis, Ph.D., School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, 315 Ferst Dr. NW, IBB Building, Room 1306, Atlanta, GA 30332.
Transplantation. 2014 Sep 15;98(5):507-13. doi: 10.1097/TP.0000000000000247.
Cell-based insulin therapies can potentially improve glycemic regulation in insulin-dependent diabetic patients. Enteroendocrine cells engineered to secrete recombinant insulin have exhibited glycemic efficacy, but have been primarily studied as uncontrollable growth systems in immune incompetent mice. Furthermore, reports suggest that suboptimal insulin secretion remains a barrier to expanded application.
Genetic and tissue engineering strategies were applied to improve recombinant insulin secretion from intestinal L-cells on both a per-cell and per-graft basis. Transduction of insulin-expressing GLUTag L-cells with lentivirus carrying an additional human insulin gene-enhanced secretion twofold. We infected cells with lentivirus expressing a luciferase reporter gene to track cell survival in vivo. To provide a growth-controlled and immune protective environment without affecting secretory capacity, cells were microencapsulated in barium alginate. Approximately 9×10(7) microencapsulated cells were injected intraperitoneally in immune competent streptozotocin-induced diabetic mice for therapeutic efficacy evaluation.
Graft insulin secretion was increased to 16 to 24 mU insulin per day. Transient normoglycemia was achieved in treated mice two days after transplantation, and endogenous insulin was sufficient to sustain body weights of treated mice receiving minimal supplementation.
Glycemic efficacy of a bioartificial pancreas based on insulin-secreting enteroendocrine cells is insufficient as a standalone therapy, despite enhancement of graft insulin secretion capacity. Supplemental strategies to alleviate secretion limitations should be pursued.
基于细胞的胰岛素疗法有可能改善胰岛素依赖型糖尿病患者的血糖调节。经过基因工程改造以分泌重组胰岛素的肠内分泌细胞已显示出血糖调节功效，但主要是在免疫缺陷小鼠中作为不可控生长系统进行研究。此外，报告表明胰岛素分泌欠佳仍是扩大应用的障碍。
应用基因和组织工程策略，在单个细胞和移植物水平上改善肠道L细胞的重组胰岛素分泌。用携带额外人类胰岛素基因的慢病毒转导表达胰岛素的GLUTag L细胞，可使分泌增加两倍。我们用表达荧光素酶报告基因的慢病毒感染细胞，以追踪其在体内的存活情况。为了在不影响分泌能力的情况下提供一个生长可控且具有免疫保护作用的环境，将细胞微囊化于海藻酸钡中。将约9×10⁷个微囊化细胞腹腔注射到经链脲佐菌素诱导的免疫健全糖尿病小鼠体内，以评估治疗效果。
移植物胰岛素分泌增加至每天16至24 mU胰岛素。移植后两天，治疗组小鼠实现了短暂的血糖正常，且内源性胰岛素足以维持接受少量补充的治疗组小鼠的体重。
尽管移植物胰岛素分泌能力有所增强，但基于分泌胰岛素的肠内分泌细胞的生物人工胰腺作为单一疗法的血糖调节功效仍不足。应寻求减轻分泌限制的补充策略。
