Crossing the intestinal barrier with nanomedicine

Although the oral administration of drugs is often the most suitable option for patients, most proteins and peptides —the latter small proteins— designed to treat diseases cannot be administered via this route. The main problem is that the gastrointestinal tract though which these large compounds pass impedes their transport. The digestive system breaks them down into small parts, thereby cancelling out their therapeutic action. The European project TRANS-INT (New oral nanomedicines: transporting therapeutic macromolecules across the intestinal barrier), part of the VII Framework programme of the European Union, will tackle this challenge. It aims to achieve the rational design of oral nanomedicines that are safe, inexpensive and efficient.

“The availability of peptides that can be taken orally would considerably improve the treatment of chronic diseases such as diabetes and rheumatoid arthritis. If these disorders could be treated orally, the problems associated with injected drugs would be avoided, and we could probably better control the therapeutic doses”, explains Ernest Giralt, coordinator of the Chemistry and Molecular Pharmacology Programme at the Institute for Research in Biomedicine (IRB Barcelona) and senior professor of the University of Barcelona. Dr. Giralt, head of the Design, Synthesis and Structure of Peptides and Proteins Lab at IRB Barcelona, and the associate researcher, Dr. Meritxell Teixidó, form part of the macro-consortium TRANS-INT, which involves 17 European members, including universities, research centres and companies, with experts in nanopharmaceutical technology, biopharmacy, organic chemistry, immunology, physiology and pharmacology.

Professor Giralt is one of the leading international authorities in the design and development of nanotransporters with the capacity to cross biological barriers, such as the blood-brain barrier, to transport drugs into the brain, and the gastro-intestinal barrier. Expertise in the latter is now supporting TRANS-INT: “our task within this project is to design and prepare peptides that can serve as shuttles to carry these kinds of drugs across the intestinal barrier”, explains the researcher Meritxell Teixidó.

After more than twenty years of study, the design of nanotransporters has until now been based mainly on the traditional knowledge of biological barriers acquired through the “assay-error” method. According to researchers involved in the project, to make breakthroughs in this field it is crucial to understand the behaviour of nanotransporters in the biological system from a systematic viewpoint and in depth. This explains the motto of the consortium is: “Understand the barrier, understand the transporter”. TRANS-INT, which will last for 5 years, is coordinated by Prof. María José Alonso, from the University of Santiago de Compostela (USC).