Helical‐Like Assembly of Nateglinide as Coating for Oral Delivery of Insulin and Their Synergistic Prevention of Diabetes Mellitus

• Published in: Advanced science 2023-10, Vol.10 (29), p.e2301879-n/a
• Main Authors: Li, Yanfei, Chen, Lihang, Xu, Yu, Li, Sihui, Yan, Huijia, Chen, Tao, Hua, Ziqi, Wu, Di, Zhao, Runan, Hu, Jiangning
• Format: Article
• Language: English
• Subjects: Diabetes; Fourier transforms; Glucose; helical nanofibers; Hydrogen; Mechanical properties; Morphology; nateglinide; oral delivery; Peptides; Scanning electron microscopy; self‐assembly; Spectrum analysis
• ISSN: 2198-3844; 2198-3844
• DOI: 10.1002/advs.202301879

Oral delivery of antidiabetic active components promises to free millions of people from daily suffering who require routine injections. However, oral insulin (Ins) and other short‐acting compounds such as nateglinide (NG) in harsh gastrointestinal tract still face great challenging, including low bioavailability, and rapid elimination. In this study, inspired by the self‐assembly of phenylalanine‐based peptides in nature, it is showed that NG a small phenylalanine derivative, assembles into left‐handed helical nanofibers in the presence of Ca2+. These helical NG nanofibers functioned as a coating layer on the surface of Ca2+‐linked alginate (Alg) microgels for the effective encapsulation of Ins. As expected, the sustained release and prolonged circulation of Ins and NG from the Ins‐loading Alg/NG microgels (Ins@Alg/NG) in the intestinal tract synergistically maintain a relatively normal blood glucose level in streptozotocin‐induced diabetic mice after oral administration of Ins@Alg/NG. This further confirms that Ins@Alg/NG ameliorated Ins resistance mainly through activating Insreceptor substrate 1 (IRS1), protein kinase B (AKT), and AMP‐activated protein kinase (AMPK), as well as by repressing glycogen synthase kinase‐3β (GSK‐3β). The strategy of using the assembly of NG as a coating achieves the oral delivery of insulin and showcases a potential for the treatment of diabetes. In brief, nalglinide (NG) can form a hydrogel coating on the surface alginate microspheres (Alg) rich in calcium ions, and encapsulate Ins in the microspheres to obtain Ins‐loading microspheres (Ins@Alg/NG). Through oral administration, NG and Ins are successfully released in the intestine to explore the synergistic protective effect and mechanism of the two on diabetic mice.