An unpublished finding promises to end the use of injections
Written by Curtis M. Wong
Researchers have found a molecule that, when dissolved in water, produces vesicles that are used to transport any type of medication by mouth or through the skin through patches. They keep the drugs they carry unalterable, protect them from gastric juices and deposit them in the body’s cells. The tests carried out so far, with insulin and an antitumor, in mice, have had successful results.
The dreaded injections that generate so much rejection among children and adults could become an ephemeral memory. An unpublished finding of scientists from the National University of Río Cuarto promises an unprecedented change in the treatment of chronic diseases, such as diabetes or cancer: They discovered a molecule, which when dissolved in water, forms vesicles of unique characteristics, which would allow administer any type of medication orally or topically.
Vesicles are microscopic and constitute a type of system that resembles transport “vehicles” capable of carrying insulin molecules or other drugs inside.
Since insulin was discovered in the early twentieth century, stringent efforts were made to fight diseases such as type 1 diabetes. However, nothing managed to free patients from punctures. The needles are uncomfortable, painful and annoying but, despite the rejection they generate, they are still the only thing insulin-dependent people have in hand to keep glucose levels at bay.
But, this may change, and it is no accident. As a result of more than twenty years of studies, UNRC researchers discovered a type of vesicles that can encapsulate drugs, transport them into the body and fulfill their therapeutic mission.
The novelty is that this vesicle managed to successfully overcome the multiple barriers that the human body puts to the administration of drugs by the oral route.
Insulin is very sensitive to changes in the microenvironment in which it is found. If ingested orally, stomach acids destroy it.
However, this gallbladder proved to be resistant to gastric juices and did not suffer any type of alteration, and therefore the medication it was carrying, at least up to an hour and a half after its ingestion. This is more than enough time to reach the intestine and, from there, to the bloodstream to associate with the cells, the final destination to deliver the remedy.
The preliminary results pleasantly surprised university researchers. They were at the doorstep of a transcendent finding: to make a vesicle, which can carry a therapeutic substance like insulin, resist the aggressive environment of the stomach. This is something that so far no one could get. Therefore, many of the medications that are currently on the market have no other route of application than by injection.
Scientists from other parts of the world found similar systems that are also capable of resisting passage through the stomach, but precisely that resistance forms a stiffness that prevents them from releasing the drug. Therefore, they are useless as therapeutic alternatives.
The discovery made at the National University of Río Cuarto is valuable precisely for overcoming these barriers.
The numerous in-vitro tests conducted at the UNRC laboratories traced a promising picture for the use of this vesicle, baptized right here on campus by its discoverers as BHD-AOT. And shortly after walking, the same thing that had been artificially proven in-vitro, was corroborated in mice.
The gallbladder, loaded with insulin, again demonstrated its potential. It was administered orally and compared with intraperitoneal and subcutaneous injections. In all cases, glucose levels were reduced.
What does this mean? That the gallbladder with insulin can overcome all barriers of the gastrointestinal tract, which is absorbed through the intestine, which reaches the cell and is capable of delivering the medication. Neither more nor less: it successfully fulfills the functions it has to fulfill.
This work is part of the scientific activity carried out by the Organized Systems Group (GSO) of the Department of Chemistry of the Faculty of Exact Sciences, which include, among others, doctors Mariano Correa, Darío Falcone, Patricia Molina, Fernando Moyano, the emeritus researcher Juana Chessa and the doctoral fellow of the Conicet Soledad Stagnoli.
Dr. Correa, principal investigator of Conicet, is one of the scientists responsible for this work. He said: “It was more than twenty years of research that led us to discover that a molecule called surfactant, when dissolved in water, spontaneously formed a type of aggregates called vesicles. It had features that attracted our attention. Therefore, we did some physical-chemical studies of its structure and found that stomach acids did not destroy or modify it. ”
“Traditionally, these systems are formed using phospholipid molecules to which energy is applied so that they have a determined and uniform size. The molecule discovered in the laboratories of our University, forms the vesicles spontaneously; that is, you just have to dissolve it in water and, without any extra treatment. It is organized by forming vesicles of a uniform size and ready to be administered to the body. This is fundamental for an industrial level development because, by not needing extra steps, the cost of a future formulation would be reduced, ”said the local scientist.
The goal was to find an alternative therapy, less annoying and painful for diabetics who have to inject insulin several times a day.
Insulin is a hormone that, so far, cannot be administered orally. It happens that it is extremely sensitive to changes in the microenvironment in which it is found. Logically, if ingested by the mouth, the stomach gastric juices disarm it and it does not work.
“The challenge, then, was to find something that protects it, but also resists in the digestive system for a sufficient time so that it can reach the intestinal tract without changes and, from there, join the bloodstream to fulfill its therapeutic function,” Dr. Correa pointed out. And this vesicle comfortably met the requirements.
However, the road ahead was still long and demanding. It was necessary to take an indispensable step: make sure that it was not toxic to the organism. This was a work that Soledad Stagnoli did particularly in the framework of her PhD thesis in Biological Sciences, directed by Dr. Ana Nieblyski, professor at the Faculty of Exact Sciences. First, he tested with cells in-vivo and then in mice.
“Both cells and living organisms, subjected to different concentrations, did not express rejection or show toxic effects,” Stagnoli said. He added: “Any organism can develop an immune response, but in this case it did not happen, which was very positive. In any case, it was also necessary to assess its stability against the different biological conditions: is it resistant to stomach acids and blood properties? Because one thing is what you get in pure water and another is blood. It’s one thing to do tests in the laboratory and another is to test it in living organisms. ”
“Therefore, we made simulations with the presence of proteins, of salts; that is, the body’s own components. We even corroborate that the system is stable. How did we realize? Because it kept its size unchanged, even after a month, ”he explained.
At these preliminary steps, another decisive one would follow: incorporate insulin into the gallbladder. And again, to answer questions: is the system still stable with the drug inside? Does it persist unchanged in different biological conditions? For how long?
Subsequent studies allowed to verify that insulin was located inside the gallbladder and was protected, as intended. In addition, it was resistant to extreme acidity conditions and stable over time.
Dr. Correa explained: “Within the structure of insulin there are amino acids that are fluorescent, which excited at a certain wavelength can be seen. Its intensity is highly dependent on the environment where the hormone is dissolved. But, once inside the gallbladder, that emission intensity is so low that no more traces of light could be observed, which clearly showed that insulin was protected inside. We changed the acidic pH and nothing happened; that is to say that it was still protected inside the gallbladder. If we saw fluorescent light it was because we were losing insulin, but it never happened. Also, the hormone retained its biological or therapeutic potential without alterations. ”
But more questions had to be answered: can the drug be absorbed through the intestine and reach the blood? Insulin has to come into contact with cell receptors to work. If the answer was no, all the investigation would have failed.
“The in-vitro tests allowed us to confirm that the gallbladder had associated with the cell,” Stagnoli said. Now, is it on the surface of the cell or inside the cell? Again, the response was encouraging. “We made a cross section and found that the gallbladder was inside the cell. This is produced by a process known as endocytosis. It means that the cell catches the gallbladder. We tested with other techniques and saw that not only did this incorporation event occur, but it stuck to the cell membrane and delivered the medication. We needed this mechanism to work, and it worked. The vesicle membrane is contacted with the cell membrane; therefore, the cell takes insulin through its receptors. ”
Only after having traveled this long and complex path, the decision was to make tests in vivo, in mice.
Stagnoli commented: “We resort to the common routes, that is to say intraperitoneal and subcutaneous injections, and of course to the oral administration of insulin. The injections managed to reduce glucose levels, and so did our gallbladder. ”
“What does this mean? That the gallbladder with insulin can overcome all barriers of the gastrointestinal tract, which is absorbed through the intestine, which reaches the cell and is capable of delivering the medication. Neither more nor less, I was successfully fulfilling the functions I had to fulfill, ”said the researcher.
These studies had a strong interdisciplinary component. They combined the effort of researchers from the Department of Chemistry and a group from the Department of Molecular Biology led by Dr. Niebylski. In addition, they involved two recently created Institutes of double dependency Conicet-UNRC, which are Agroindustrial and Health Development (IDAS) and Environmental Biotechnology and Health (INBIAS). ”
The fact that the gallbladder enters the cell also provided other important information: it could be used to transport drugs such as tumors. This type of drugs cannot be released on the surface of the cell. It has to reach the inside of it because it is insoluble.
The achievements motivated local scientists to expand the scope of the system and use the gallbladder discovered to transport anticancer drugs.
With this scientific proposal, Soledad Stagnoli obtained a scholarship in Germany. The objective was to test the local finding in the topical administration of a natural antitumor drug known as curcumin.
Like all anticancer drugs, this medicine is insoluble, so it needs a means that transports it to the cells so that it is not lost in the body.
With the collaboration of German scientists, Stagnoli’s work focused on achieving the administration of the drug through the skin. He said: “Vesicles are suspended in water, so they need a mesh or a support that contains them. A kind of patch that incorporates a viscous biomaterial (hydrogel) was used. Inside, the system (the vesicles) was encapsulated, carrying within it the antitumor drug. ”
“It is very difficult to use drugs topically because there is an innate barrier of defense that has the skin (stratum corneum) that prevents them from crossing it. But these vesicles that we discover in our University have the particularity of being very flexible, they are deformable, they can adapt their shape to pass through the pores and without losing the drug they transport, ”said the researcher.
This represents a transcendent scientific breakthrough, because other systems that are studied in the world are either rigid and cannot penetrate the skin, or in their attempt to do so lose part of the medication they carry.
Stagnoli remarked: “This vesicle managed to overcome these obstacles, but also, due to the characteristics of the patch we use, a controlled degradation can be done, that is, it allows the doses to be regulated according to the needs. Drug release can be induced. After several studies, we were able to determine that, as the patch degrades, the vesicles, in turn, are released, not altered, the properties of the drug remain intact and, what is better, they can cross the barriers of the skin”.
“This is proven in different rat trials. We put gel loaded with vesicles on the skin and then, under it, we took aliquots – small portions of the sample. The antitumor drug we use has fluorescent properties. This allowed us to verify that the more the patch degraded over time, the more vesicles with curcumin released, ”he added.
Dr. Mariano Correa stressed the versatility of the system discovered in this house of studies: “It can be adapted to oral administration or, as was seen in this last work, also topically.”
In Germany, we are already thinking about using these types of systems as an alternative for chemotherapies. In addition, these vesicles are very efficient because they deliver all the cargo of drug they carry. This is a significant aspect for patients, not only of cancer, but of any other disease, since toxicity in the organism is reduced. Unlike other therapies, with this type of vesicles you can apply the necessary dose and nothing else. No portion of the dose is lost in the bloodstream.
There are many studies worldwide that, through different mechanisms, have tried to achieve similar results, but so far they failed to be efficient. Most of them require a high concentration of medication because much of it is lost along the way. This makes them toxic to the body.
Instead, the gallbladder studied by Rio Cuarto scientists, as it could be tested, uses the right amounts of medicine because it has no losses and can deliver it where it should: in the cell.
The system discovered at the local University works successfully, although it is not yet in the clinical stage. Its potential is enormous and could transform the way medical procedures are currently carried out. (Source: National University of Río Cuarto / Argentina Investiga)