A groundbreaking development from Kumamoto University, spearheaded by Associate Professor Shingo Ito, presents a potential alternative to daily insulin injections. Utilizing a cyclic peptide known as the DNP peptide, this innovative approach enables the oral delivery of insulin, a method previously deemed unattainable.
Two Innovative Strategies for Enhanced Absorption
The research team devised two distinct strategies to facilitate insulin's passage through the intestinal barrier:
- Mixing method (interaction-based): By combining a modified "D-DNP-V peptide" with zinc-stabilized insulin hexamers, the team observed remarkable results. When administered orally to various diabetes models, including chemically induced (STZ mice) and genetic (Kuma mice) models, this combination effectively normalized blood sugar levels. Remarkably, stable glucose control was achieved with a once-daily dose over three consecutive days.
- Conjugation method (covalent-based): Employing click chemistry, the researchers bonded the DNP peptide directly to insulin, forming a "DNP-insulin conjugate." This method demonstrated comparable efficacy in lowering blood sugar, confirming the peptide's role in facilitating insulin transport across the intestinal lining.
Practicality of Oral Insulin with Lower Doses
A significant hurdle in the development of oral insulin has been the requirement for exceptionally high doses, often exceeding ten times that of injections. This new platform notably reduces that need, achieving a pharmacological bioavailability of approximately 33-41% when compared to subcutaneous injection. Such efficiency suggests that oral insulin could soon become a viable option for everyday use.
Promising Future for Diabetes Management
"Insulin injections pose a daily challenge for many patients," stated Associate Professor Shingo Ito. "Our peptide-based platform opens up a new avenue for oral insulin delivery, with potential applications extending to long-acting insulin formulations and other injectable biologics."
The research findings were published in the journal Molecular Pharmaceutics. The team is now advancing their studies, which will include testing in larger animal models and systems that replicate human intestinal conditions, paving the way for future clinical applications.
