
Human islets cultivated in the macaques spleen. Credit: Lei Dong / Nanjing University and Jian Xiao / Wenzhou Medical University
Researchers at Wenzhou Medical University have redesigned the spleen as a viable site for the transplantation of islets, allowing the control of long -term diabetes without the load of complete immunosuppression. The remodeling of the spleen based on nanoparticles has enabled the transplanted islets of mouse, rat and humans to restore normal blood sugar in diabetic rodents and cynomolgus macaques.
In type 1 diabetes, the immune system destroys native beta cells, Insulin producing cells Installed in pancreatic clusters called Langerhans islets. The transplantation of the islets transfers these clusters of the donors’ pancrèsses in the portal vein of the recipient’s liver, where they settle in hepatic microvascularization. Once in place, they resume insulin secretion to reduce or eliminate injections and restore glycemic control.
Hepatic transplantation has significant drawbacks. The immune attack, the low oxygen tension and the rigidity of the liver fabric often destroy most of the transplanted islets in a few hours. More than 70% of the cells are destroyed before the transplant, forcing dependence on several donors per recipient and dull therapeutic success.
Alternative sites such as the eye, the omentum and the striated muscles have been explored, but each introduces complications ranging from invasive surgery to poor survival of islets or abnormal insulin administration models.
In the study, “the transplantation of islets in the renovated rats with immunomodlative nanoparticles”, ” published In Translational scientific medicineThe researchers have designed rats with nanoparticles of silica coated with glucomannaine to create a vascularized and immunosuppressive environment for transplanted islets.

Thyroid catering with vascular network in the spleen. Credit: Lei Dong / Nanjing University
The researchers tested the transplantation strategy in mice and cynomolgus macaques. Murine models have received mouse or rat islets, while the macaques were established with human islets of two donors. The diabetic conditions were induced using streptozotocin in both species. In macaques, the injection of nanoparticles and the transplantation were guided by B-Urtrasound and followed by tailor-made immunosuppressive patterns.
Konjac glucomannaine hairstyle silica nanoparticles have been injected into mouse and macaques rats to reshape the tissue architecture and modulate local immunity.
In mice, the procedure involved four nanoparticles injections over two weeks after surgical translocation of the spleen in an extraperitoneal site. In macaques, nanoparticles were delivered each week for four weeks under ultrasound orientations in the upper, medium and lower splenic poles.
ISLOCS transplants have been prepared from mouse, rat or human pancreas using the digestion of collagenase and the purification of density. The mouse and rat islets were transplanted directly into remodeled rats in diabetic mice.
Human islets have been injected into macaque Raoutages under ultrasound guidance and supported by the immunosuppression adjusted for the experimental group. Glycemic status was followed by serial blood sugar measures, insulin and peptide C tests and glucose tolerance tests.
The islets transplanted into renovated rats made up of stable and durable transplants. In diabetic mice, mouse and rat islets survived for 90 days and maintained the typical endocrine structure. Without reshaping, the transplants were lost in a week.
Rapid vascular integration supported the survival of the graft. The blood vessels infiltrated transplants in a few days and dense vascular networks formed in the two weeks. In macaques, human islets remained intact for at least 28 days and showed clear revascularization without structural complications.

The mouse spleen turned into a liver. Credit: Lei Dong / Nanjing University, Scientific advances2020, DOI: 10.1126 / SCIADV.AAZ9974.
The renovated rats have developed a local immune environment that supported the tolerance of the graft. In mice, the treatment of nanoparticles has expanded regulatory T cells and M2 macrophages while reducing the effectors and pro-inflammatory cytokines. The grafted islets have triggered a minimum of antibodies or responses from cytokines, even through the barriers of species.
In macaques, the remodeled rats have shown similar immune remodeling, with an expression of anti-inflammatory genes and activation of attenuated T cells. In vitro tests have confirmed that nanoparticles have removed the proliferation of T lymphocytes and favored the polarization of macrophages to a regulatory phenotype.
The islets transplanted into redesigned rats quickly restored control of blood sugar among diabetic mice. Normoglycemia was obtained in a few days and maintained up to 90 days with mouse and rat islets. Glucose tolerance and insulin secretion corresponded to those of healthy controls.
Among macaques, human islet transplants supported insulin and the release of Peptide C for at least 28 days. Glycemic stability has been maintained under reduced immunosuppression, and splenectomy has reversed the effect, confirming the dependent function of the graft.
Researchers have concluded that remodeling of the spleen provides a viable alternative to liver islet transplantation. Technical microenvironment supported the survival and function of islets through species with reduced immune intervention.
The approach offers a less invasive, more reliable and less risky method to restore insulin production in type 1. diabetes. Clinical trials are always necessary, the initial results seem promising as a strategy that could bring therapies closer to islands of clinical routine use.
More information:
Mi liu et al, islets transplantation in immunomodlative breasts in nanoparticles and rats, Translational scientific medicine (2025). DOI: 10.1126 / Scitranslmed.adj9615
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Quote: The transplant of missing islets restores glycemic control in type 1 diabetes without complete immunosuppression (2025, May 26) recovered on May 27, 2025 of https://medicalxpress.com/News/2025-05-spleen basés in- islet-transplantation-glycemic.html
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