DELIVER is a European Industrial Doctorate programme coordinated by NUI Galway working to break insulin-dependency in juvenile diabetic patients. It provides training for 6 Early Stage Researchers in the field of advanced therapies for innovative pancreatic islet transplantation. In Tübingen, we are focused on the development of transplant biofunctionalization and device design.
In a study published in Advanced Science, we demonstrated that Nidogen-1 (NID1) protects pancreatic β-cells and increases insulin secretion in an in vitro ischemia model, which mimics the conditions seen at an islet transplantation site. We tested the impact of dosages at 20, 30, and 40 µg mL−1 NID1 on pseudoislet function under normoxic conditions. NID1-treated pseudoislets significantly increased insulin secretion at all dosages; with 30 µg mL−1 reaching the maximum effect. IF staining of NID1-treated pseudoislets cultured under normoxic conditions showed a significant increase in E-cadherin when compared with the controls. NID1 had no effect on cell death under normoxic conditions, assessed by the quantification of TUNEL+ cells and cleaved caspase-3 staining. In hypoxic conditions, NID1 rescued the loss of insulin secretion that was lost in control cultures, preserved the significant increase in E-cadherin seen in normoxia, and significantly reduced cell death. We showed that NID1 binds and signals through integrin αvβ3 as seen by the upregulation of pFyn, Src, pSrc, and Rac1/cdc42, which leads to the activation of the mitogen‐activated protein kinases (MAPK) pathway, including the kinases extracellular signal‐regulated kinase 1/2 (Erk 1/2) and mitogen‐activated protein kinase 1/2.
Published in Tissue Engineering, we systematically investigated the impact of the spatial distribution on cocultures of human β-cells and endothelial cells (ECs), showing that the architecture of pseudoislets significantly affects β-cell functionality. Magnetic levitation allowed the stable formation of heterotypic pseudo-islets with defined spatial distributions of β-cells and HUVECs. In addition, we showed that the stimulatory capabilities of ECs on β-cells were best utilized when a β-cell composed pseudoislet is surrounded by an outer layer of ECs, emphasizing that the spatial distribution as well as cell–cell interactions are crucial for an increased insulin secretion and, therefore, β-cell functionality. Together, these promising results lay the foundation for upcoming study to further improve the in vitro test model and investigate coculture interactions of human β-cells and ECs en route to develop prevascularized transplantable islet grafts.
Published in Matrix Biology, we developed an endocrine pancreas-on-a-chip model based on a tailored microfluidic platform, which enables self-guided trapping of single human pseudo-islets. Continuous, low-shear perfusion provides a physiologically relevant microenvironment especially important for modeling and monitoring of the endocrine function as well as sufficient supply with nutrients and oxygen. Human pseudo-islets, generated from the conditionally immortalized EndoC-βH3 cell line, were successfully injected by hydrostatic pressure-driven flow without altered viability. To track insulin secretion kinetics in response to glucose stimulation in a time-resolved manner, dynamic sampling of the supernatant as well as non-invasive real-time monitoring using Raman microspectroscopy was established on-chip.