Tissue Engineering And Nanotheranostics

“9.61x6.69” b2815 Tissue Engineering and Nanotheranostics

Directed Differentiation of Human Pluripotent Stem Cells 85

conjunction with definitive functional characterization of the result-

ing cells to determine likeness for adult islet cells.

In 2012, Rezania et al. described a four-stage protocol to differ-

entiate a highly enriched population of 98% PDX1 positive pancreatic

progenitor cells.^38 They used Activin A to induce definitive endoderm

formation and then sequentially treated the cells with additional fac-

tors including FGF7, Noggin, retinoic acid, SANT1, Alk5i, and

TBP.^38 They showed that these cells could rescue hyperglycemic con-

ditions when transplanted to a mouse with drug-induced diabetes and

observed that the in vivo maturation of the transplanted pancreatic

progenitors mimicked human fetal pancreatic development.^38 In 2014,

Pagliuca et al. reported a three-dimensional scalable culture system

for generating beta cells in vitro with 85% efficiency for deriving

PDX1 positive cells (Fig. 1).^39 Using a growth factor mediated

approach, they generated beta cells that not only responded to

changes in glucose in vivo, but also in vitro.^39 They confirmed that

these cells expressed mature beta cell markers, as opposed to fetal cell

markers, and demonstrated subcellular structure similar to mature

beta cells.^39 Further research is required to evaluate the similarity of

Fig. 1. Schematic illustrating the beta cell directed differentiation protocol devel-
oped by Pagliuca et al. using growth factor mediated transition from pluripotency
through endodermal and progenitor states to functional beta cells.^39