According to Centers of Disease Control (CDC), 25.8 million Americans were diagnosed with diabetes in 2010, and more than 300 million people were affected worldwide. One potential future treatment for diabetes is transplantation of bioengineered pancreas capable of restoring insulin function. However, bioengineering of the complex pancreas function is a significant engineering feat. It calls for appropriate combinations of cells, with biomaterials that provide structural support and a suitable extracellular environment to maintain cell survival and function in vitro and in vivo.
The first objective of this work is to investigate a suitable 3D bioscaffold to support pancreatic cell types. Our result demonstrated that perfusion-decellularization of whole pancreas effectively removes cellular material but retains intricate three-dimensional microarchitecture and crucial extracellular matrix (ECM) components. To mimic pancreatic cell composition, we recellularized the whole pancreas scaffold with acinar and beta cell lines and cultured up to 5 days. Our result showed successful cellular engraftment within the decellularized pancreas, and the resulting graft gave rise to higher insulin gene expression over individual ECM proteins.
The second objective of this work is to evaluate the feasibility to repopulate the native organ-derived scaffolds with renewable cell types such as differentiating human pluripotent stem cells (hPSC). We developed an in-house bioreactor to support the regenerative reconstruction of pancreas. Our result demonstrated that hPSCs cultured and differentiated as aggregates are more suitable than the parallel adherent cultures for organ repopulation. Upon continued culture with chemical induction in bioreactor, the seeded PP aggregates grow within the 3D organ scaffolds with homogeneity and mature in situ into monohormonal C-peptide positive cells.
The last objective of this work is to evaluate the matrix-specificity of organ-derived ECM. We evaluated this by developing a miniaturized ECM array composed of organ-specific matrices derived from decellularized pancreas, liver and heart. Interestingly, our result showed higher PP cell adhesion and differentiation on liver-ECM over pancreas- and heart-ECM, suggesting that the requirement for ‘like-to-like” basis for tissue engineering approaches may not always be the case. Overall, the findings from this dissertation represent a notable step toward bioengineering of pancreas as an alternative therapeutic solution for diabetes
