09 January 2013


Man on a chip

Marina Astvatsaturyan, MednovostiAn experiment with Russian participation is currently underway in Germany, the results of which will make it clear whether laboratory animals in the trials of new medicines can be replaced by a device that reproduces the functions of the human body.

The idea of such a replacement is in the air, and this is due to the fact that existing protocols for testing potential drugs on cell cultures and animals have a number of limitations, among them not least high cost and low predictive power. Now an alternative approach is being developed all over the world, including in Russia – preclinical tests in a microbioreactor.

Such an "imitator" of an organism called "Homunculus" (Homunculus, man – Latin) is being created at the Moscow Scientific and Technical Center BioClinicum. Dmitry Sakharov, General Director of the Bioclinicum, told the media about the capabilities of the microbioreactor.

Until recently, there were two main approaches to preclinical testing: cellular technologies and animal testing. Currently, all medicines are first tested on cell cultures, then on animals, and only after that on humans.

What is the disadvantage of cellular technologies? After all, they give an unsystematic answer. They test only one or at best two types of cells at the same time and look at how these cells react to medicinal substances – assess toxicity, in some cases – a decrease in proliferative activity, the effect on differentiation, and other factors.

The second campaign is animal testing. Yes, animals have a systematic answer. If we inject some substance, say, orally, it first enters the intestine, is absorbed through the intestinal walls, is somehow processed, then enters the bloodstream, after that it enters the liver, where it is exposed to liver enzymes. There is a metabolism, and toxic products can be formed. But the problem here is that substances that are successfully tested on animals do not always work on humans. Initially, they start with a large number of substances, 10 percent pass the first stage, then one percent remains, and eventually one substance out of 10 thousand candidate drugs enters the market. As a result, animal testing is very expensive. It is known that now it costs several billion dollars to bring the substance to the market, and it takes up to 15-20 years from the start of testing to the release of the substance as a drug.

Corresponding Member of the Russian Academy of Sciences, Doctor of Biological Sciences Alexander Tonevitsky, Scientific Director of the Bio-Clinic:

This transition from animals to humans is the hardest, the most expensive, the most difficult, because drugs are becoming more and more complicated, they are no longer just chemically simple molecules, they are more and more specific. And it is not easy to guess that there will definitely be no complications. We are currently developing different technologies so that the Ministry of Health can recommend the Homunculus microbioreactor (maybe in parallel for now) for testing certain drugs, comparing them with animals.

What is the advantage of a microbioreactor? This is a platform on the basis of which it is possible to study the effects of various substances on models of human organs. We can simultaneously use several models – skin, liver, neuronal tissue, intestines, kidneys, thus modeling the system. We create models of organs. The first approach is based on cell lines that are standardized and the same in all laboratories of the world, the second is based on the biopsy material that is obtained from a specific patient.

Senior Researcher of the Bioclinicum Alexander Rusanov:

the first direction is toxicological research, that is, testing of medicinal and cosmetic preparations. We can apply the substance to the skin model, watch how it penetrates through the skin, it is possible that it will somehow change. The skin has its own enzyme systems that can metabolize these substances. Then the substance enters the bloodstream and only after that it gets into the liver model. That is, we do not just add this substance to the liver model, but only after it has already penetrated through the skin. Or it didn't penetrate. And then it is unclear why to look at its toxicity to the liver, if this substance does not reach it in this way. If the substance penetrates, it can potentially be toxic. The microbioreactor "Homunculus" also allows you to monitor the development of chronic toxicity. There is a certain time limit set by European standards for testing chronic toxicity – 28 days. And we strive to ensure that cell models are cultured in our microbioreactor for 28 days. All that is needed for this is to periodically change the nutrient medium.

Do you analyze liquids at the outlet of the bioreactor?Yes, firstly, it is an analysis of the cultural environment.

If our cells are destroyed, various intracellular enzymes are released, the concentration of metabolites may change, for example, lactate (an important indicator of the acid-base state of the organism – MA) may appear, hypoxia may develop, changes in the glycolysis cycle begin, etc. Another thing is that we can extract cell models from the microbioreactor and analyze the genome, transcriptome or proteome, find out how the expression of genes has changed, how the content of some key proteins has changed. Maybe all the cells remained alive, but they significantly changed their functions. Or, for example, liver cells transformed, adipose tissue formed. All this can be seen.
We can make a large number of models at the same time, and there is no need for animals. Here we have 20 chips in which cell models are cultured, we analyze them every other day, after 5 days, after 28 days, and now it is possible to test various drugs.

That is, we are not talking about one chip, but about a set?Up to four chips can be connected to each device – the control unit.

You can use, for example, 10 devices, that is, 40 chips, and simultaneously watch the effects of different drugs, while varying the concentration and exposure time.

The second direction is the use of a microbioreactor for personalized medicine.

To do this, do you analyze the biopsy material in the Homunculus?Yes.

For example, there are five types of breast cancer, they are treated with different medications. It is not always possible to recognize these types, and the medicine may not work. Why torment a person if we can take five pieces of biopsy and see the effect of five drugs or more, evaluate which of them treats, and specifically use this drug to conduct therapy. That is, not to take a medicine that will either work or not.

Alexander Tonevitsky: We have 50,000 women diagnosed with breast cancer a year. Our experience of communicating with clinicians over these two or three years has shown that, despite the high qualifications of doctors, not everyone is cured. Relatively speaking, 15 percent have a very bad prognosis, 15 percent have a good one, and 70 percent have a "gray zone". There are hormone-sensitive and hormone-insensitive types of tumors. And now a new drug appears, in particular, the antibody herceptin. Russia buys it for 800 million rubles. About a third of patients get what they need, but two thirds of patients do not need it, and this, unfortunately, is wasted money. But if you choose the right strategy in advance, then, most importantly, you can increase the number of people who will receive the right appointment. We learned how to work with a small number of cancer cells, samples obtained by needle biopsy. By cultivating them for several days in a microbioreactor and acting on this culture with a drug, you can get information about the response of the transcriptome to the therapy used. And it costs nothing. In our microbioreactor, a disposable chip costs about $100. Compared to the huge amount of money that will be spent later, this is nothing. The chip is a one-time one. A control unit is needed, but this is also not a very expensive domestic device. Thus, the chance that all this will be brought to the clinic is very important.

When was the idea of a microbioreactor born?In the 90s.

In the mid-2000s, our colleague and partner Uwe Marx (Uwe Marx) from the Technical University in Berlin began doing this in Germany, he is a graduate of the scientific director of the Bio-Clinic Alexander Grigoryevich Tonevitsky, with whom he did not interrupt friendly and professional ties.

Chief Engineer of the Bioclinicum Evgeny Trushkin:

In Germany, they made chips, but there was a problem with electronics. We have a group of engineers here who assemble control units that regulate the operation of the microbioreactor, including the pumping rate of the medium. We entered the project as collaborators, but it turned out that our devices are better than those produced by the Germans.

Now there is a big experiment going on there. They want to compare the microbioreactor with mice. 40 chips, 40 models and 40 mice are involved. The task of the experiment is to investigate the effect of a certain substance on the cellular models of organs under cultivation in a microbioreactor, and compare the results with the experiment on mice.

What drugs will be involved in this Berlin experiment?I know for sure about one drug, troglitazone, which was used to treat people with diabetes and was withdrawn from the market because it is potentially hepatotoxic.

It has even already been tested in a microbioreactor, on a skin and liver model. It is not reported to affect the skin, and in the liver, as the first three-day observations showed, the number of apoptotic cells increases, the expression of different genes changes. It seems to be, yes, it really affects the liver. But those were the initial experiments and now they want to launch a long experiment for a month.

Can we say that some candidate drugs have entered the market or at least have approached clinical trials thanks to this system?Not yet.

But I would like to note that two years ago some types of animal testing were banned in Europe. In this case, only the cellular model remains at the disposal of the testers of new substances. As I said, cells give a non-systemic response. I and many others are sure that microbioreactors will be a replacement for mice, because these are both human cells, not mouse cells, and a systemic response, and you can look at several models at once. In Russia, they will probably ban it, but later. We are still looking at Europe, and environmentalists and "greens" are all present here.

In America, in general, there is a special staff of people in biomedical institutes who monitor the progress of tests so that animals do not suffer excessively.In America, by the way, there was a lag in this area, in terms of microbioreactors.

But in the middle of 2012, a lot of money was allocated for this by both DARPA and NIH, and they are urgently trying to catch up with us. So far, half a step behind, but, apparently, they will catch up. We develop our own systems, they develop their own.

The microbioreactor consists of two modules. The first is a disposable cell block in which cells are cultured and key sensors are located to determine their physiological and functional state.

The second is a control unit that supports and regulates the parameters of the cell block (temperature, speed and circulation path of the nutrient medium), as well as primary processing of signals from sensors located in a replaceable cell block (determination of the concentration of key cellular metabolites).

The control unit will be able to be connected to a personal computer, on which, with the help of specially developed software, the microbioreactor will be controlled, as well as the analysis and interpretation of data obtained during cell cultivation and determination of their main parameters.

Portal "Eternal youth" http://vechnayamolodost.ru09.01.2013

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