Protecting Beta Cells to Avoid Injections
Implanted strings of protected beta cells could help the body produce insulin once again
Minglin Ma, PhD
Assistant Professor in the Department of Biological and Environmental Engineering at Cornell University
ADA Research Funding
Junior Faculty Award
Minglin Ma, PhD, may not have diabetes, but he’s very aware of the difficulties the disease causes. “When I go to conferences, I hear patients talking about how rough it is to manage this disease,” he says. “It’s really tough for people with type 1. You always have to worry.”
The Cornell University bioengineer hopes an invention he’s working on could help take away some of that worry. In type 1 diabetes, the body’s immune system turns against the specialized cells that produce insulin. Called beta cells, these insulin factories are found in the pancreas. When they’re destroyed, only injections and insulin pumps can give the body the insulin it needs.
Researchers have been working for decades to find ways to implant donor islet cells (which contain insulin-producing beta cells) or beta cells made from stem cells. A successful outcome would be a game-changer for people with diabetes, giving them a renewed ability to produce insulin and eliminating the need for injections and blood glucose monitoring.
The problem, Ma says, is keeping those insulin-producing cells alive. Implanted beta cells come under attack from the same misguided immune reaction that killed off the original ones in the pancreas.
That’s why the implanted beta cells need devices that protect them while still letting them release insulin. Ideally, such a gadget would work similar to a tea bag: Like tea leaves, the beta cells would stay safely inside, while insulin and blood glucose move in and out in a process called “biotransfer.”
After years of work, two approaches have come to the fore. One of them is called microencapsulation. This technique embeds islet cells in tiny beads that float freely in the abdominal cavity. The small size of these little spheres allows the beta cells inside the maximum contact with the bloodstream, and they’re easier for the body to accept than a large device—something scientists call “biocompatibility.”
The problem with microcapsules is that they’re nearly impossible to remove. Imagine thousands of grains of sand floating freely in your body, and you’ll have a good idea of the potential problems involved in putting them in and, in case of complications or changes in the body, removing them. “You have to implant hundreds of thousands of beads,” Ma says. “And it’s hard to take them out if complications occur or a transplant fails.”
To solve that problem, some researchers are going in the other direction. Macroencapsulation means thin boxes, about half the size of a credit card, packed with hundreds of thousands of islet cells. “Macroencapsulation devices can be replaced or retrieved,” Ma explains. “But the capacity is not good—you can only encapsulate a limited number of cells.” And many of those cells are stuck in the middle of the box where they can’t access the surface.
With the help of a grant from the American Diabetes Association, Ma is working on a solution that would combine the best of both approaches. “We’d like to use microcapsules in a way similar to a macro device,” he says.
Ma, a specialist in high-tech materials, wants to link microencapsulation beads together using string made from naturally occurring material—something like suture thread, which wouldn’t cause a reaction in the body and wouldn’t break down.
If it works, Ma’s device would overcome a major drawback of microcapsules by allowing doctors to fish them out of the body, if necessary, using minimally invasive techniques. At the same time, it would improve on so-called macroencapsulation devices by taking advantage of the way tiny beads allow insulin-producing cells greater contact with the abdominal cavity—it’s essentially a string of microscopic beads.
So far, Ma’s idea is still in the very early stages. “We don’t know yet exactly how it would work,” he says. “And we haven’t yet tried it on humans.” In fact, the ADA’s grant was the first funding the young researcher received after starting his own lab. If his invention works in animals—he’s begun early trials in mice and dogs—it would still be many years before it’s ready for human use.
Ma says the ADA’s grant played a critical role. “It really helped me take off and gather data and interest,” he says. “If everything works, patients wouldn’t have to worry about their blood sugar anymore.”
The ADA wishes to express gratitude for the generous donation made by Joe and Marianne Adams.
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If you would like to support diabetes research, such as that being done by Minglin Ma, PhD, please go to diabetes.org/researchdonation.