title: Use of glucose-responsive material to regulate insulin release from constitutively secreting cells.
abstract: Genetically-engineered cells offer a solution to the cell availability problem in tissue engineering a pancreatic substitute for the treatment of insulin-dependent diabetes. These cells can be non-beta cells, such as hepatocytes or myoblasts, retrieved as a biopsy from the same patient and genetically engineered to secrete recombinant insulin constitutively or under transcriptional regulation. However, the continuous or slowly responsive insulin secretion dynamics from these cells cannot provide physiologic glucose regulation in patients. Our objective consists of using such cells as an insulin source and of regulating insulin release by incorporating a glucose-responsive material, which acts as a control barrier for insulin in a cell-material hybrid device. Experiments were performed with insulinoma betaTC3 cells, HepG2 hepatomas, and C2C12 myoblasts, the latter two genetically-modified to constitutively secrete insulin. The control barrier consisted of concanavalin A (con A)-based glucose-responsive material, which forms a gel at low and a sol at high glucose concentrations. Results demonstrated that the device released insulin at a higher rate in response to glucose challenges. In contrast, a device containing an inert hydrogel instead of glucose-responsive material released insulin at an essentially constant rate, irrespective of the surrounding glucose concentration. Necessary material improvements include increased sensitivity to glucose, so that the material responds to physiologically relevant glucose concentrations, and increased stability. The prospects of developing a properly functional, implantable substitute based on engineered non-beta cells and glucose-responsive material, and the material and device improvements that need to be made prior to in vivo experiments, are discussed.
authors.affiliation: Georgia Institute of Technology, School of Chemical and Biomolecular Engineering, 315 Ferst Drive, IBB Building, Room 1306, Atlanta, Georgia 30332, USA.
authors.forename: S-Y
authors.initials: SY
authors.lastname: Cheng
authors.forename: I
authors.initials: I
authors.lastname: Constantinidis
authors.forename: A
authors.initials: A
authors.lastname: Sambanis
mesh_terms: D000464:Alginates / Q000737:chemistry; D000818:Animals; D002460:Cell Line; D045744:Cell Line, Tumor; D002470:Cell Survival; D003208:Concanavalin A / Q000737:chemistry; D003922:Diabetes Mellitus, Type 1 / Q000628:therapy; D005947:Glucose / Q000737:chemistry* / Q000494:pharmacology; D020723:Glucuronic Acid / Q000737:chemistry; D006003:Glycogen / Q000737:chemistry; D006603:Hexuronic Acids / Q000737:chemistry; D006801:Humans; D020100:Hydrogels / Q000138:chemical synthesis / Q000737:chemistry*; D007328:Insulin / Q000235:genetics / Q000378:metabolism*; D000078790:Insulin Secretion; D008567:Membranes, Artificial; D019397:Pancreas, Artificial; D044367:Phase Transition / Q000187:drug effects; D011076:Polycarboxylate Cement / Q000737:chemistry; D023822:Tissue Engineering / Q000379:methods*; D014162:Transfection
chemical_list: D000464:Alginates; D006603:Hexuronic Acids; D020100:Hydrogels; D007328:Insulin; D008567:Membranes, Artificial; D011076:Polycarboxylate Cement; D003208:Concanavalin A; C005506:polycarbonate; D020723:Glucuronic Acid; D006003:Glycogen; D005947:Glucose