Giving transplanted islets a blood supply: promising, and still in mice
In a Science Advances study, adding engineered blood-vessel cells to transplanted islets helped them survive and reversed diabetes in mice.
Another type 1 headline, another study in mice, and it is worth knowing which is which. This time, researchers found a way to help transplanted insulin-making cells survive by giving them their own blood supply, and in mice it was enough to reverse diabetes. It goes after a genuine weakness: when islet cells (the insulin-making cells) are transplanted, many die because they do not get enough blood and oxygen in their new home. Adding engineered blood-vessel cells helped them connect up and keep working. That is encouraging and aimed at a real problem, but it is a mouse study, years away from people, and it changes nothing about type 1 care today.
- Transplanted islet cells (the insulin-making cells type 1 destroys) often fade because they lack a good blood supply in their new site.
- The study added engineered blood-vessel cells alongside the islets, which helped them plug into the body’s circulation and survive.
- In mice, this was enough to reverse their diabetes, which is a promising sign for the approach.
- The team also looked at placing cells under the skin rather than in the liver, a spot that is easier to reach and monitor.
- This is an animal study, an early stage, and realistically years from anything a person could receive.
The simple idea: cells need plumbing
Islet transplants already exist, including on the NHS for a small number of people, but they have a stubborn problem. When the insulin-making cells are placed into the body, a lot of them die in the first days and weeks because they are cut off from a proper blood supply. Cells need oxygen and nutrients delivered constantly, and freshly transplanted islets often do not get enough before new blood vessels have grown in.
The study, published in early 2025, tried to fix that at the source. The researchers transplanted the islets together with engineered blood-vessel cells, so the graft came with the beginnings of its own plumbing. The combined cells connected to the host circulation quickly, which gave the islets the nutrition and oxygen they needed to survive and keep working, and in the mice this was enough to reverse their diabetes.
Real problem, real progress, still in mice
What makes this worth noticing is that it goes after a known reason transplants fade, rather than promising a miracle. If insulin-making cells could reliably survive long term, transplants would last longer and help more people. Placing them under the skin, another part of the work, would also make them easier to monitor and, if needed, remove, compared with the liver where islets currently go.
The honest caveat is the size of the gap between a mouse and a person. Mouse studies are where many promising ideas begin, and also where a lot of them quietly end. Human trials, safety testing, and working out how to make this at scale are all still ahead, which realistically means years, not months. If you have heard a decade of cure-in-mice headlines, your caution is reasonable; this is a solid step in the lab, not a treatment waiting for you.