Insulin-Dendrimer Nanocomplex for Multi-Day Glucose-Responsive Insulin Therapy in Ossabaw Miniature Swine with Type 1 Diabetes

• Published in: Physiology (Bethesda, Md.) Md.), 2024-05, Vol.39 (S1)
• Main Authors: Xian, Sijie, Xiang, Yuanhui, Liu, Dongping, Fan, Bowen, Mitrová, Katarína, Ollier, Rachel, Alloosh, Muhammad Ali
• Format: Article
• Language: English
• ISSN: 1548-9213; 1548-9221
• DOI: 10.1152/physiol.2024.39.S1.1934

Abstract only Background: Therapy for type 1 diabetes resulting from immunogenic destruction of the insulin-producing pancreatic beta cells has been a challenge for over 100 years. Delivering exogenous insulin to maintain euglycemia is a delicate balance between plasma glucose transport to insulin-responsive tissues, glucose absorption in the gut, and the pharmacodynamics of insulin. The synthesis of short- and long-acting insulins and use of insulin pumps have made great strides in the standard of diabetes care. Despite advances, hypoglycemia is a major limitation. There is no approved therapy that offers glucose-responsive insulin function. Toward this end we engineered a nanoscale complex combining both electrostatic and dynamic-covalent interactions between a synthetic dendrimer carrier and an insulin analogue modified with a high-affnity glucose-binding motif. Hypothesis: This insulin nanocomplex will yield an injectable insulin depot providing both glucose-sensitive and long-lasting insulin availability in a translation preclinical model. Methods: Ossabaw minature swine (41-59 kg; N=6) were made diabetic with alloxan, which was confirmed by stable hyperglycemia (228±43 mg/dL). Oral glucose tolerance tests (OGTT) were conducted at the diabetic baseline and each of the following 6 days after one subcutaneous injection of the insulin nanocomplex. Results: The basline OGTT elicted blood glucose of 350-450 mg/dL for 90 min of the 150 min OGTT, while serum insulin remained at ~5 μU/mL, nearly the detection limit. In contrast, 3 h after injection of insulin nanocomplex (~0.8-0.9 mg/kg) blood glucose decreased to 71±12 mg/dL. Subsequent OGTTs on days 1-6 increased blood glucose from normoglycemia to ~200 mg/dL and serum insulin increased to ~60-220 μU/mL, followed by return to nearly normolgycemia hours after the OGTT. Hypoglycemia was avoided in all pigs. Conclusions: The subcutaneous nanocomplex of a modified insulin and a synthetic dendrimer carrier produced a glucose-responsive insulin depot for week-long glycemic control following a single routine injection. These findings offer great promise for overcoming the hypoglycemia risk of intensive glucose control. Future studies should include additional physiological challenges of exercise and nutritional states. Support: Juvenile Diabetes Research Foundation 5-CDA-2020-947-A-N, Helmsley Charitable Trust 2019PG-T1D016 and 2102-04994, American Diabetes Association Pathway 1-19-ACE-31, National Science Foundat