Preserving Nanotherapy-Induced Allogeneic Murine Islet Graft Tolerance During Distal Methicillin-Resistant Staphylococcus aureus Skin Infection

Researchers have found a way to keep islet transplants working long-term, without the need for lifelong immunosuppression. They created a nanotherapy called rapamycin-loaded polymersomes (rPS) that helps islet transplants survive in mice. The rPS kept neutrophils, which fight infections, working properly even though it also slowed down the immune system's ability to cause damage.

When mice were given the rPS treatment, they recovered well after being infected with Methicillin-resistant Staphylococcus aureus (MRSA), a dangerous skin infection. However, those mice had a 43% lower chance of survival compared to mice that weren't given rPS. Even though the surviving mice still produced normal amounts of insulin in response to sugar, their islet transplants were not as well accepted as those that hadn't had the infection.

The researchers believe this reduction in allograft acceptance is due to a spike in inflammatory chemicals like IL-6 and TNF- produced by the infection. By giving infected mice a single dose of methylprednisolone, a drug that reduces inflammation, they were able to cut down on the IL-6 and TNF- production without affecting the neutrophilia (a type of white blood cell).

This treatment helped infected mice survive twice as long as those that didn't receive the inflammation-reducing drug, with a 80% survival rate. The study shows that carefully controlling inflammation can help islet transplants stay effective even after a serious infection.