Researchers from Rice University have created an insulin-producing implant to automatically regulate blood glucose levels and treat Type 1 Diabetes.
In 2020, the Centers for Disease Control and Prevention reported around 34.2 million Americans suffering from diabetes, 90 to 95 per cent of which were Type 2 diabetes and the rest being Type 1. However, despite being much less prevalent, Type 1 is hardly preventable and much less curable as those who suffer from Type 1 diabetes become dependent on lifelong insulin injections to regulate their blood glucose levels. And even with these injections, balancing insulin intake with eating, exercise, and other activities is difficult, to the extent that fewer than one-third of Type 1 diabetics in the U.S. consistently achieve target blood glucose levels.
To replace these injections and improve insulin therapy, bioengineers from Rice University are creating an insulin-producing implant for Type 1 diabetics using 3D printing and smart biomaterials. Supported by a grant from the Juvenile Diabetes Research Foundation (JDRF), this three-year project between the laboratories of Omid Veiseh and Jordan Miller plans to utilise insulin-producing beta cells from human stem cells. These beta cells will then be used to create an implant that can sense and regulate blood glucose levels at any given time. In essence, the team hopes to replicate the functions of the pancreas.
However, mimicking the natural behaviour of a pancreas is a difficult and complex task to achieve. As pointed out by Veiseh, "If we really want to recapitulate what the pancreas normally does, we need vasculature. And that's the purpose of this grant with JDRF. The pancreas naturally has all these blood vessels, and cells are organised in particular ways in the pancreas. Jordan and I want to print in the same orientation that exists in nature."
Considering their objective, the importance of the vasculature cannot be overemphasised. To show that the implants can properly regulate blood glucose levels for long periods, the team needs to engineer their beta cells to be able to respond to rapid changes in blood sugar levels. A rapid response is crucial since a delay in responding to high or low sugar levels can result in a roller coaster-like effect, wherein insulin levels repeatedly rise and fall to dangerous levels.
To address this potential delay, the scientists have come up with a solution, and that is to “get implanted cells in close proximity to the bloodstream so beta cells can sense and respond quickly to changes in blood glucose," as explained by Miller. Ideally, the beta cells should be no more than 100 microns away from a blood vessel.
Additionally, the team will also have to ensure that their lab-grown implant can be successfully integrated into the host. Miller reported that the team is using a combination of pre-vascularisation through advanced 3D bioprinting and host-mediated vascular remodelling to give each implant several shots at host integration.
They also plan to protect the insulin-producing cells from potential attacks by the host’s immune system with a hydrogel formulation developed by Veiseh. The hydrogel material, which has been proven effective to encapsulate cell treatments in bead-sized spheres, is porous. And these pores are small enough to keep the cells inside from being targeted by immune sentinels but large enough to allow nutrients to flow in and insulin to flow out.
"Blood vessels can go inside of them," explained Veiseh regarding the hydrogel compartments. "At the same time, we have our coating, our small molecules that prevent the body from rejecting the gel. So it should harmonise really well with the body."
Source: Rice University