Stiffness-tunable oral nanoparticles restore islet β cells and glycemic control in diabetic models

Current therapies for diabetes mellitus primarily manage blood glucose with insulin, but they do not restore critical islet β cell function, leading to lifelong dependence and the risk of hypoglycemia. Antioxidant drugs show promise for β cell repair, yet their clinical utility is hampered by poor gastrointestinal absorption and insufficient targeting to the pancreas. This study addresses these limitations by identifying ferroptosis-associated oxidative stress as a key driver of β cell death and developing a novel oral delivery system.

Researchers engineered six stiffness-gradient oral nanoparticles by embedding bent oleic acid into ordered 1,2-distearoyl-sn-glycero-3-phosphoethanolamine to encapsulate curcumin. These nanoparticles were designed to optimize membrane wrapping and minimize energetic cost for enhanced bioavailability. The team evaluated the nanoparticles in diabetic models (animal species not specified) to assess their ability to improve intestinal M cell transcytosis, macrophage-mediated hitchhiking, pancreatic curcumin accumulation, and ultimately, their impact on β cell repair and glycemic control.

The study identified ferroptosis-associated oxidative stress as a crucial mechanism of islet β cell death. Nanoparticles with intermediate stiffness demonstrated optimal properties, significantly enhancing intestinal M cell transcytosis and macrophage-mediated hitchhiking. This led to a substantial increase in pancreatic curcumin accumulation.

Pancreatic curcumin accumulation increased by ~4.5-fold compared to controls, demonstrating superior targeting. In diabetic models, this optimized nanoparticle formulation effectively suppressed ferroptosis-associated oxidative stress. This suppression promoted in situ islet β cell repair, leading to the restoration of insulin homeostasis and autonomous glycemic control. Notably, the treated models maintained normoglycemia without experiencing hypoglycemia, even after the cessation of treatment, outperforming traditional insulin therapy in long-standing diabetes management.