Many drugs cannot be administered orally since they cannot be taken up by the intestines. All attempts to solve this problem have thus far resulted in unacceptable risks of side-effects, mainly because the intestinal wall is so severely impacted that not only the drug but other substances, including toxins, can be absorbed. Now a team of scientists from Uppsala University in Sweden have made a major discovery that may solve the problem.
The intestinal wall functions as an effective obstacle to keep various substances from passing from the intestine out into the body. Some drugs, like antibiotics, can use the transport canals that exist, while other important medicines cannot. The porosity of the intestinal wall is determined by a sort of “filter,” so-called “tight junctions,” consisting mainly of two types of proteins: claudins and occludins. Each such protein molecule interacts with a corresponding molecule in the adjacent cell by a loop-shaped bond consisting of peptides. To let more substances pass through, it’s necessary to temporarily increase the porosity of the filter--without damaging the cell. Thus far research has been directed toward changing the porosity via the claudins, which are more dynamic and changeable, but this has always brought with it undesired and irreversible effects that increase the risk of cell damage.
Instead, the Uppsala scientists, led by Professor Per Artursson, have focused on the other protein: the occludins, which are more static proteins. Experiments have been carried out on cells and have yet to be applied to living organisms. They synthesized peptides that correspond to different sequences in the loop that joins the canal between two cells. One of these peptides proved to increase the porosity of the intestinal wall when it was coupled with occludin molecules, but only from one side of the wall. From the other side, corresponding to the one from the intestine out into the body, the molecules proved to lump together or to be destroyed by enzymes before they had time to affect the filter. But the research team went one step further. By adding a fatty acid as a shield for the peptide part, they managed to increase the porosity from the other side as well. What’s more, the scientists succeeded in guiding the effect on the intestinal wall, from rapid and short to a longer lasting impact.
Anneli Waara | alfa
Electrical 'switch' in brain's capillary network monitors activity and controls blood flow
27.03.2017 | Larner College of Medicine at the University of Vermont
Laser activated gold pyramids could deliver drugs, DNA into cells without harm
24.03.2017 | Harvard John A. Paulson School of Engineering and Applied Sciences
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
27.03.2017 | Earth Sciences
27.03.2017 | Life Sciences
27.03.2017 | Life Sciences