Engineered tools to study endocrine dysfunction of pancreas

Abstract

Pancreas, a vital organ with intricate endocrine and exocrine functions, is central to the regulation of the body's glucose levels and digestive processes. Disruptions in its endocrine functions, primarily regulated by islets of Langerhans, can lead to debilitating diseases such as diabetes mellitus. Murine models of pancreatic dysfunction have contributed significantly to the understanding of insulitis, islet-relevant immunological responses, and the optimization of cell therapies. However, genetic differences between mice and humans have severely limited their clinical translational relevance. Recent advancements in tissue engineering and microfabrication have ushered in a new era of in vitro models that offer a promising solution. This paper reviews the state-of-the-art engineered tools designed to study endocrine dysfunction of the pancreas. Islet on a chip devices that allow precise control of various culture conditions and noninvasive readouts of functional outcomes have led to the generation of physiomimetic niches for primary and stem cell derived islets. Live pancreatic slices are a new experimental tool that could more comprehensively recapitulate the complex cellular interplay between the endocrine and exocrine parts of the pancreas. Although a powerful tool, live pancreatic slices require more complex control over their culture parameters such as local oxygenation and continuous removal of digestive enzymes and cellular waste products for maintaining experimental functionality over long term. The combination of islet-immune and slice on chip strategies can guide the path toward the next generation of pancreatic tissue modeling for better understanding and treatment of endocrine pancreatic dysfunctions.

FIG. 1.

Anatomy of the pancreas. (a) General anatomy of the pancreas highlighting the three regions of the pancreas as well as the main and accessory pancreatic ducts into the digestive tract. (b) Representative diagram of the cellular architecture of the endocrine and exocrine pancreas. (c) Pancreatic islet with β, α, δ, γ [also known as pancreatic polypeptide (PP)] cells identified. Reproduced with permission from Atkinson et al., Diabetologia 63(10), 1966–1973 (2020). Copyright Springer Nature. (d) Intrapancreatic signaling. Inhibitory and stimulatory pathways of endocrine hormones within the pancreas and the cells they act on as it pertains to glucose regulation. Arrows depict stimulation and flat lines depict inhibition. Adapted from Fang-Xu et al. Copyright 2011 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike-3.0 License.

FIG. 2.

Islet isolation and slice extraction. Pancreas received as a whole organ from a willed organ donor can be utilized for islet isolation, pancreatic slicing, and sectioning. Organ donors typically provide a limited amount of tissue and decreased extraction quantity and quality makes donor tissue less suited for islet isolation. Surgically removed pancreatic tissue samples are well suited for tissue slicing. Brief advantages (+) and disadvantages (–) for each method are also listed. Reproduced with permission from Gloyn et al., Nat. Metab. 4(8), 970–977 (2022). Copyright Springer Nature.

FIG. 3.

Live pancreatic slices and slice on a chip technology. (a) 1. Pancreatic tissue samples are acquired from a donor. 2. Pancreatic tissue samples are suspended in agarose. 3. 120-μm-thick slices are sectioned from blocks of the agarose suspended pancreatic samples. 4. Pancreatic slices are then removed for culture. Adapted from Alver et al. Copyright RSC, extended to authors for reproducing their work. (b) Pancreatic slices had traditionally been cultured in transwells until the Dominguez-Bendala lab developed a culture dish with an oxygen permeable bottom that increased the functionality of slices in long-term culture. Adapted from Qadir et al. Open access article distributed under the terms of the Creative Commons CC BY license. (c) Cross section view of the SliceChip platform for culture and perfusion of pancreatic slices developed by Alver et al. Copyright RSC, extended to authors for reproducing their work. (d) Dark field microscopy of pancreatic slices with islets identified by red arrows. Adapted from Huber et al. Reproduced with permission from JoVE. (e) Reflected light image of a pancreatic slice with islets indicated by white arrows. Adapted from Huber et al. Reproduced with permission from JoVE.

FIG. 4.

Organ on chip manufacturing methods. (a) Photolithography is used to create a stamp of the desired microfeatures for replica molding. A thin layer of photoresist is spin-coated on a silicon wafer. A photomask with a pattern of the desired microscale features is laid onto the photoresist. The wafer, photoresist, and photomask structure is exposed to high-intensity ultraviolet (UV) light that activates the uncovered photoresist for solidification in a developing solution. This process creates a mold with complementary surface topography to the photomask for use in replica molding. (b) Forming an organ on chip with replica molding. Liquid PDMS is cast onto the mold generated by the process in (a). Here the mold features a microfluidic channel design with two inlets and one outlet. The cast PDMS stamp is removed from the mold and bonded to a flat glass surface to fully form the fluid channel. A real-world depiction of a two-chamber microfluidic device is shown to the right. Reproduced with permission from Bhatia and Ingber, Nat. Biotechnol. 32(8), 760–772 (2014). Copyright Springer Nature. (c) Schematic representation of the components and process used to make a computer aided design (CAD) model into a physical device. The worktable provides XY motion for an immobilized substrate. A spindle that spins at a high rate and can move along the Z axis holds a cutting tool that cuts into the workpiece to form the desired microfeatures on the substrate. Reproduced with permission from Guckenberger et al., Lab Chip 15(11), 2364–2378 (2015). Copyright RSC.

FIG. 5.

Overview of the current state of the art for pancreatic Organs on Chips. (a) An osmotically driven tissue-engineered islet platform adapted from Jun et al. Open access article distributed under the terms of the Creative Commons CC BY license. (b) A multi-channel tissue-engineered islet platform for drug assessment. Reproduced with permission from Tao et al., Lab Chip 19(6), 948–958 (2019). Copyright RSC. (c) A dual channel OoC for the maturation of patient derived tumor organoids. Adapted from Haque et al. Open access article distributed under the terms of the Creative Commons CC BY license. (d) A tissue-engineered pancreatic acinus on a chip. Reproduced with permission from Venis et al., Lab Chip 21(19), 3675–3685 (2021). Copyright RSC. (e) An islet on a chip platform with onboard insulin analysis. Reproduced with permission from Glieberman et al., Lab Chip 19(18), 2993–3010 (2019). Copyright RSC. (f) A resealable islet on a chip platform with serial GSIS capabilities. Adapted from Patel et al. Open access article distributed under the terms of the Creative Commons CC BY license. (g) A generalized islet on a chip platform with onboard label-free biosensors. Adapted from Rodriguez-Comas et al. Licensed under a Creative Commons Attribution 4.0 International License. (h) A multi-tissue OoC to model the interplay between liver and pancreatic tissues. Adapted from Bauer et al. Licensed under a Creative Commons Attribution 4.0 International License. (i) A multi-modal analytic microfluidic platform for the assessment of islet function. Reproduced with permission from Mohammed et al., Lab Chip 9(1), 97–106 (2009). Copyright RSC. (j) An islet chip capable of culturing ex vivo islet tissues under differential shear stresses. Reprinted from Sokolowska et al., Biosens. Bioelectron. 183, 113215 (2021) with permission from Elsevier.

FIG. 5.

Overview of the current state of the art for pancreatic Organs on Chips. (a) An osmotically driven tissue-engineered islet platform adapted from Jun et al. Open access article distributed under the terms of the Creative Commons CC BY license. (b) A multi-channel tissue-engineered islet platform for drug assessment. Reproduced with permission from Tao et al., Lab Chip 19(6), 948–958 (2019). Copyright RSC. (c) A dual channel OoC for the maturation of patient derived tumor organoids. Adapted from Haque et al. Open access article distributed under the terms of the Creative Commons CC BY license. (d) A tissue-engineered pancreatic acinus on a chip. Reproduced with permission from Venis et al., Lab Chip 21(19), 3675–3685 (2021). Copyright RSC. (e) An islet on a chip platform with onboard insulin analysis. Reproduced with permission from Glieberman et al., Lab Chip 19(18), 2993–3010 (2019). Copyright RSC. (f) A resealable islet on a chip platform with serial GSIS capabilities. Adapted from Patel et al. Open access article distributed under the terms of the Creative Commons CC BY license. (g) A generalized islet on a chip platform with onboard label-free biosensors. Adapted from Rodriguez-Comas et al. Licensed under a Creative Commons Attribution 4.0 International License. (h) A multi-tissue OoC to model the interplay between liver and pancreatic tissues. Adapted from Bauer et al. Licensed under a Creative Commons Attribution 4.0 International License. (i) A multi-modal analytic microfluidic platform for the assessment of islet function. Reproduced with permission from Mohammed et al., Lab Chip 9(1), 97–106 (2009). Copyright RSC. (j) An islet chip capable of culturing ex vivo islet tissues under differential shear stresses. Reprinted from Sokolowska et al., Biosens. Bioelectron. 183, 113215 (2021) with permission from Elsevier.