An in vitro Perfused Macroencapsulation Device to Study Hemocompatibility and Survival of Islet-Like Cell Clusters

Abstract

Transplantation of hydrogel-encapsulated pancreatic islets is a promising long-term treatment for type 1 diabetes that restores blood glucose regulation while providing graft immunoprotection. Most human-scale islet encapsulation devices that rely solely on diffusion fail to provide sufficient surface area to meet islet oxygen demands. Perfused macroencapsulation devices use blood flow to mitigate oxygen limitations but increase the complexity of blood-device interactions. Here we describe a human-scale in vitro perfusion system to study hemocompatibility and performance of islet-like cell clusters (ILCs) in alginate hydrogel. A cylindrical perfusion device was designed for multi-day culture without leakage, contamination, or flow occlusion. Rat blood perfusion was assessed for prothrombin time and international normalized ratio and demonstrated no significant change in clotting time. Ex vivo perfusion performed with rats showed patency of the device for over 100 min using Doppler ultrasound imaging. PET-CT imaging of the device successfully visualized metabolically active mouse insulinoma 6 ILCs. ILCs cultured for 7 days under static conditions exhibited abnormal morphology and increased activated caspase-3 staining when compared with the perfused device. These findings reinforce the need for convective transport in macroencapsulation strategies and offer a robust and versatile in vitro system to better inform preclinical design.

Rue and clove microspheres: antiamebic activity, hemocompatibility, and release kinetics

“…Therefore, no immediate concerns were raised regarding the hemocompatibility of alginate or the devices themselves in an in vitro setting, and this would require investigations of the immune response with various immune components such as antibodies, other proteins, and immune cells, to monitor adhesion, adsorption, activation, and penetration into the biomaterial (64). In addition, similar studies have shown that the use of alginate as a biomaterial is hemocompatible (64,65).…”

Engineering Vascularized Islet Macroencapsulation Devices: An in vitro Platform to Study Oxygen Transport in Perfused Immobilized Pancreatic Beta Cell Cultures

“…The vascular template was then removed, leaving a central hollow channel, and the device was connected to a tubing loop for perfusion culture. Device assembly is described in detail in our previous work ( Fernandez et al, 2021 ). A general schematic of the device geometry is provided in Figure 3A .…”

“…Alternatively, vascular prosthesis strategies offer the potential for enhanced oxygenation via blood convection, as well as long-term graft functionality without the need for device maintenance. Considering this, we have previously highlighted the need for robust in vitro platforms to study blood-device interactions and predict in vivo performance ( Fernandez et al, 2021 ). We fabricated a system that comprises a perfusable culture device housing a cell-laden hydrogel ( Fernandez et al, 2021 ).…”

“…Considering this, we have previously highlighted the need for robust in vitro platforms to study blood-device interactions and predict in vivo performance ( Fernandez et al, 2021 ). We fabricated a system that comprises a perfusable culture device housing a cell-laden hydrogel ( Fernandez et al, 2021 ). This hydrogel is irrigated with artificial vasculature to permit fluid convection.…”

“…This hydrogel is irrigated with artificial vasculature to permit fluid convection. Using this platform, we have shown that alginate-encapsulated islet-like clusters (ILCs) exhibited higher cell survival under perfusion when contrasted with their static counterparts ( Fernandez et al, 2021 ). This platform can be further used to assess factors impacting cell survival and function to better predict in vivo behaviour.…”