A team from Wenzhou Medical University, Nanjing University, and the University of Macau conducted the research, results published May 21, 2025, in Science Translational Medicine. The study targeted type 1 diabetes, in which the immune system destroys insulin-producing islet cells of the pancreas. Study authors identified immune rejection and insufficient blood supply as barriers to transplanted islet cell survival and function. While islet cell transplantation into the liver is considered clinically validated, the oxygen-poor environment and vessel architecture of the liver lead to loss of function within a year. The team had previously reprogrammed mouse spleens to assume liver functions and, through gene editing, grown liver tissue without cell transplantation.
Nanoparticles remodel the spleen into a specialized niche
To transform the spleen, the team led by Lei Dong and Jian Xiao developed nanoparticles made from silicon dioxide modified with konjac glucomannan, called KSiNPs, that convert the spleen into an immunosuppressive niche rich in extracellular matrix. By enhancing extracellular matrix support, accelerating blood vessel growth, and suppressing immune attacks, the team created an ideal environment for transplanted cells. Nanoparticle injection and islet cell transplantation into macaque spleens proved feasible under ultrasound guidance.
2025 study: stable insulin and C-peptide secretion for weeks to months
In streptozotocin-induced type 1 diabetes models in mice and macaques, transplanted islet cells restored normal blood sugar levels with stable insulin and C-peptide secretion, a byproduct of insulin production, for 90 days in mice and 28 days in macaques. In rodents, engraftment succeeded without immunosuppression; in primates, it required varying degrees of immune suppression. Human islet tissue matured in remodeled spleens of macaques, which the organization views as evidence of compatibility with human and animal cells.
Comparison: a second spleen-based diabetes strategy
The team led by Lei Dong pursued a second approach. In the journal Diabetes, it described in 2025 islet cell constructs wrapped with hepatocytes and fibroblasts. Hepatocytes, through low expression of von Willebrand factor, reduce immediate immune inflammation mediated by blood, while fibroblasts support islet cell survival through extracellular matrix formation. In mouse studies, this cellular protection maintained blood sugar in the normal range for over a year while requiring 40 percent fewer donor cells. Standard islet cell transplantation to the liver shows a 60 percent failure rate by comparison.
What remains before human application
The announcement itself notes that clinical applications require thorough safety validation. As of May 2025, clinical application was estimated to be several years away. The next research step involves cultivating patient-specific organs from induced pluripotent stem cells. Dong describes as a future vision minimally invasive, ultrasound-guided administration for cultivating customized organs, while Xiao envisions a minimally invasive platform on which patients could one day grow tailor-made organs from their own cells. The study authors view their animal model success as a promising strategy against type 1 diabetes.