Tiny Bilirubin-Filled Capsules Could Improve Survival of Transplanted Pancreatic Cells


Source: North Carolina State University

Summary: Researchers have improved the survival rates of pancreatic islet cells in vitro in a low-oxygen environment by intervening them with tiny nanoparticles filled inside with encapsulated bilirubin.


Type 1 diabetic (T1D) patients are unable to produce enough insulin naturally. One of the treatments for T1D is pancreatic islet transplantation – in which group of cells from a donor pancreas are transplanted into the diabetic patient, where they produce insulin in response to glucose levels and help controlling diabetes. Islet transplantation is a non-invasive procedure but the main drawback is the high rate of cell death (nearly 70% of the transplanted cells die within 72 hours of the procedure) after transplantation. Researchers from the North Carolina State University have improved the survival rates of pancreatic islet cells in vitro in a low-oxygen environment by intervening them with tiny nanoparticles filled inside with encapsulated bilirubin. The study findings were published in the journal Cell Transplantation.

Survival rates of pancreatic islet cells in vitro are improved with bilirubin

Cytoprotective properties of bilirubin. Bilirubin has been shown to intervene at multiple levels on the pathway to islet apoptosis. Credit: Chris Adin et al/ Cell Transplantation

The researchers thought that the answer to save these transplanted islet cells might lie in a naturally occurring antioxidant, bilirubin. But the main obstacle was to deliver bilirubin to the cells of interest as it is not well soluble in water and it couldn’t be effectively taken up by the cells. To overcome this obstacle, researchers have designed a delivery vehicle – a nanocapsule made from Pluronic 127-chitosan that would enclose the bilirubin molecule, be taken up by the islet cell, and release the bilirubin inside the cell. They found that a dose of 5 micromolar bilirubin had the maximum protective benefit and preserve islet cells function where the low-oxygen death rate was only 18%. Researchers next steps include creating a treatment program for canine patients which can serve as a model for humans.

Assoc. Prof. Chris Adin said, “The cell death rate from islet transplants has been the major roadblock to this procedure’s usefulness”, “These nanocapsules provide a bilirubin delivery method that allows targeted dosing, preserving both the cells and their functionality.”


More Information: Bronwyn Fullagar et al, “Nano-Encapsulation of Bilirubin in Pluronic F127–Chitosan Improves Uptake in β Cells and Increases Islet Viability and Function after Hypoxic Stress”, Cell Transplantation (2017).

DOI: 10.1177/0963689717735112


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