Scaffold Architecture Controls Insulinoma Clustering, Viability, and Insulin Production

Abstract

Recently, in vitro diagnostic tools have shifted focus toward personalized medicine by incorporating patient cells into traditional test beds. These cell-based platforms commonly utilize two-dimensional substrates that lack the ability to support three-dimensional cell structures seen in vivo. As monolayer cell cultures have previously been shown to function differently than cells in vivo, the results of such in vitro tests may not accurately reflect cell response in vivo. It is therefore of interest to determine the relationships between substrate architecture, cell structure, and cell function in 3D cell-based platforms. To investigate the effect of substrate architecture on insulinoma organization and function, insulinomas were seeded onto 2D gelatin substrates and 3D fibrous gelatin scaffolds with three distinct fiber diameters and fiber densities. Cell viability and clustering was assessed at culture days 3, 5, and 7 with baseline insulin secretion and glucose-stimulated insulin production measured at day 7. Small, closely spaced gelatin fibers promoted the formation of large, rounded insulinoma clusters, whereas monolayer organization and large fibers prevented cell clustering and reduced glucose-stimulated insulin production. Taken together, these data show that scaffold properties can be used to control the organization and function of insulin-producing cells and may be useful as a 3D test bed for diabetes drug development.

The emerging field of pancreatic tissue engineering: A systematic review and evidence map of scaffold materials and scaffolding techniques for insulin-secreting cells

“…97 The spun fibers offer the possibility of fabricating scaffolds with a high surface to volume ratio, adaptable porosity properties, and applicability for a broad spectrum of materials. 97,98 Researchers used this relatively simple technique to produce polymer fibers from PLA, 99–101 PVA, 53,99,100,102 PCL, 53,96,103,104 polyglecaprone (PGC), 96 PEOT/PBT, 90 gelatin, 105 polyethersulfone, 106,107 silk fibroin, and collagen. One disadvantage of this fabrication method might be the difficulty of scaling up these scaffolds to allow therapeutic human dosages.…”

“…108 Blackstone et al actually showed a positive correlation between increased fiber diameter and inter-fiber distance with viability and function of the seeded cells. 105 They produced an electrospun scaffold from gelatin as a 3D cell culture platform. 105 Mostly, the electrospinning technique was applied for the fabrication of 3D cell culture templates to achieve enhanced differentiation of human adipose tissue-derived stem cells (hADSC) and human-induced pluripotent stem cells (hiPSC) into ISC 53,99,101–103,106,107 but also for the in vivo transplantation of murine islets on electrospun PCL/PGC to the intrarenal transplantation site, with greater proliferation and functional output than the control without a scaffold.…”

Engineering of microscale three-dimensional pancreatic islet modelsin vitroand their biomedical applications

“…The morphology of scaffolds has great effects on b cell viability and functionality. For instance, small-diameter, densely packed nanofibrous scaffolds can better promote the formation of large, round cell clusters and enhanced insulin production, as compared with large-diameter fibers (Blackstone et al, 2014). In another example, adipose stem cells seeded in a 3D biodegradable scaffold composed of natural polymers dextran and gelatin can effectively differentiate to islet-like clusters expressing islet-specific hormones (e.g.…”

Engineered Biomaterials for Enhanced Function of Insulin‐Secreting β‐Cell Organoids

“…[ 164 ] In immortalized cell line culture, fine control of gelatin fiber diameter and spacing can control 3D aggregation and insulin production from the β‐cell organoids. [ 165 ] In a unique layer‐by‐layer coating technique with alternating coatings of gelatin and fibronectin, mouse β‐cells formed tightly formed spheroids with increased GSIS, upregulated glucose transporter genes, and upregulated expression of connexin 36 gap junctions for improved synchronization of insulin secretion. [ 166 ] Gelatin has also be grafted with proteins necessary for differentiation (i.e., Activin A), which allows for continued presentation of the protein during hPSC differentiation and improved differentiation efficiency to the pancreatic progenitor stage.…”