Human Laminin Isotype Coating for Creating Islet Cell Sheets.

Our experimental approach toward the development of new islet-based treatment for diabetes mellitus has been the creation of a monolayered islet cell construct (islet cell sheet), followed by its transplantation into a subcutaneous pocket. Previous studies describe rat laminin-5 (chain composition: α3, β3, γ2) as a suitable extracellular matrix (ECM) for surfaces comprised of a coated temperature-responsive polymer, poly(N-isopropylacrylamide) (PIPAAm). To progress toward the clinical application of this approach, the present study attempted to identify an optimal human ECM as a coating material on PIPAAm surfaces, which allowed islet cells to attach on the surfaces and subsequently to be harvested as a monolithic cell sheet. Dispersed rat islet cells were seeded onto PIPAAm dishes coated with various human laminin isotypes: human laminin (HL)-211, HL-332, HL-411, HL-511, and HL-placenta. Plating efficiency at day 1, the confluency at day 3, and glucose-stimulated insulin secretion test at day 3 were performed. The highest value of plating efficiency was found in the HL-332-PIPAAm group (83.1 ± 0.7%). The HL-332-PIPAAm group also showed the highest cellular confluency (98.6 ± 0.5%). Islet cells cultured on the HL-332-PIPAAm surfaces showed a positive response in the glucose-stimulated insulin secretion test. By reducing culture temperature from 37°C to 20°C in the HL-332-PIPAAm group, cells were able to be harvested as a monolithic islet sheet. The present study showed that HL-332 was an optimal human-derived ECM on a PIPAAm coating for preparing islet cell sheets.