3-D physiomimetic extracellular matrix hydrogels provide a supportive microenvironment for rodent and human islet culture

Abstract

Organ-on-a-chip platforms serve as cost-efficient testbeds for screening pharmaceutical agents, mimicking natural physiology, and studying disease. In the field of diabetes, the development of an islet-on-a-chip platform would have broad implications in understanding disease pathology and discovering potential therapies. Islet microphysiological systems are limited, however, by their poor cell survival and function in culture. A key factor that has been implicated in this decline is the disruption of islet-matrix interactions following isolation. Herein, we sought to recapitulate the in vivo peri-islet niche using decellularized extracellular matrix (ECM) hydrogels. Sourcing from porcine bladder, lung, and pancreas tissues, 3-D ECM hydrogels were generated, characterized, and validated using both rodent and human pancreatic islets. Optimized decellularization protocols resulted in hydrogels with distinctive viscoelastic properties that correlated to their matrix composition. The in situ 3-D encapsulation of human or rat islets within ECM hydrogels resulted in improved functional stability over standard culture conditions. Islet composition and morphology were also altered, with enhanced retention of islet-resident endothelial cells and the formation of cord-like structures or sprouts emerging from the islet spheroid. These supportive 3-D physiomimetic ECM hydrogels can be leveraged within microfluidic platforms for the long-term culture of islets.

Evaluation of Different Decellularization Protocols on the Generation of Pancreas-Derived Hydrogels

“…Only in the recently published study by Sackett et al were the basement membrane proteins retained when the pancreatic tissue was decellularized and processed in a hydrogel form. 22 In other previously published studies, 17,21 a limited retention of collagen IV was reported, while laminin proteins were either not detected or investigated. In our study, only hydrogels treated with 1% Triton showed retention of laminin proteins, despite being lower when compared with native tissue ( Supplementary Fig.…”

“…6,7 In particular, basement membrane proteins have been shown to play an important role in maintaining beta-cell functionality, both in vivo 8 and in vitro. [9][10][11][12] Among the different scaffolds evaluated for 3D culture of islets or beta-cell lines, several decellularized tissues have recently been explored, including the pancreas, [13][14][15][16][17][18][19][20][21][22] liver, 23 lung, 21 or small intestine submucosa. 24,25 Tissue-derived biomaterials can closely mimic the microenvironment of the endogenous tissue, making them potentially more advantageous for tissue repair or in vitro models compared with other biologic or synthetic scaffolds.…”

Hydrogel platform for in vitro three-dimensional assembly of human stem cell-derived β cells and endothelial cells

“…Differentiated hESCs offer a potentially unlimited number of cells for this purpose [19], and this approach is enhanced by improving the maturation of the generated SC-β cells [20]. The inclusion of endothelial cells with SC-β cells could be combined with macroporous scaffolds that enable retrievability [16,21] or other beneficial materials [22][23][24][25][26] to develop a more comprehensive transplantation strategy for diabetes. An alternative cell type to SC-β cells are earlier pancreatic progenitors derived from hESCs.…”

Nanotechnology in cell replacement therapies for type 1 diabetes

“…Several methods have been explored that utilize the pancreas as tissue source including repopulating decellularized pancreas [162][163][164][165], culturing islets on decellularized pancreas [166], and differentiating stem cells into βcells using β-cell line produced matrix [167]. Techniques have also included other tissue sources and methods such as processing decellularized ECM into hydrogels [168,169] and culturing islets on decellularized liver [170]. Pancreatic or liver matrices have been used inside an encapsulation device [171], and construction of a bilayer transplantation device was accomplished from porcine pericardium and tendon [172].…”