Sustained Administration of β-cell Mitogens to Intact Mouse Islets Ex Vivo Using Biodegradable Poly(lactic-co-glycolic acid) Microspheres.

The development of biomaterials has significantly increased the potential for targeted drug delivery to a variety of cell and tissue types, including the pancreatic β-cells. In addition, biomaterial particles, hydrogels, and scaffolds also provide a unique opportunity to administer sustained, controllable drug delivery to β-cells in culture and in transplanted tissue models. These technologies allow the study of candidate β-cell proliferation factors using intact islets and a translationally relevant system. Moreover, determining the effectiveness and feasibility of candidate factors for stimulating β-cell proliferation in a culture system is critical before moving forward to in vivo models. Herein, we describe a method to co-culture intact mouse islets with biodegradable compound of interest (COI)-loaded poly(lactic-co-glycolic acid) (PLGA) microspheres for the purpose of assessing the effects of sustained in situ release of mitogenic factors on β-cell proliferation. This technique describes in detail how to generate PLGA microspheres containing a desired cargo using commercially available reagents. While the described technique uses recombinant human Connective tissue growth factor (rhCTGF) as an example, a wide variety of COI could readily be used. Additionally, this method utilizes 96-well plates to minimize the amount of reagents necessary to assess β-cell proliferation. This protocol can be readily adapted to use alternative biomaterials and other endocrine cell characteristics such as cell survival and differentiation status.