3-D physiomimetic extracellular matrix hydrogels

ECM Islets Schematic
Researchers prepared hydrogels from decellularized organs to maintain islet cell viability and function

Original source: Materials Today

An increasing amount of individuals are diagnosed with diabetes. Pancreatic islets are associations of cells in our pancreas. Among them, beta cells regulate blood glucose levels by producing the hormone insulin. Therefore, islets are crucial for the understanding of disease pathology, testing diabetic drug efficiency as well as discovering potential therapies. Islets are isolated from tissue by enzymatic treatment. However, it is very difficult to maintain cellular viability and function after enzymatic isolation. In the pancreas, islets are surrounded by peri-insular basement membrane (BM). During the isolation, islets are stripped of this native BM that later leads matrix signaling related cell apoptosis (anoikis) and decline in insulin secretion. To date, designer matrixes with individual extracellular matrix components (e.g collagen type IV, laminin and fibronectin) have been developed. Although these approaches helped to restore cell function and survival, supplementation with selected ECM proteins do not fully recapitulate the native BM environment. Therefore, researcher from University of Florida (United States of America) prepared hydrogels from decellularized organs to maintain islet cell viability and function. [Jiang et. alBiomaterials (2018), doi.org/10.1016/j.biomaterials.2018.08.057]. They generated acellular porcine pancreas, bladder and lung tissue by removing cells (decellularization) from the native organ while largely preserving extracellular matrix (ECM) composition, which are both major constituents of the microenvironment known to direct cell behaviors including, migration, proliferation and differentiation. They prepared fibrous, mechanically stable ECM hydrogels from these decellularized tissues. To be able to use these hydrogels in vitro and in vivo studies, biocompatibility testing is required. Therefore, it is important to ensure that the ECM hydrogels contain little or no endotoxins. The endotoxins activates the immune system which later leads apoptosis. For this study, the researcher isolated pancreatic islets from rodent and human tissues. The group studied human and rodent islet cell viability and function by embedding these cells within porcine bladder and pancreas ECM hydrogels. Encapsulated human islet cells exhibited spheroid formation without showing significant cell death. Both rodent and human islet cells were able to retain glucose responsiveness. According to researchers, decellularized ECM hydrogels allowed them to mimic the physiological microenvironment of the native islet niche. Decellularized ECM hydrogels hold a great potential in microfluidic platforms for long-term culture of islet cells.