A consortium of scientists from 29 organizations around the world, including specialists from NASA, has drawn up a strategy to increase human radio resistance so that space radiation does not interfere with humanity's conquest of space and the colonization of Mars.
A comic about how scientists will master Mars in the fight against cosmic radiation.
It looks at several avenues for future research to protect astronauts from radiation exposure, including drug therapy, genetic engineering, and hibernation technology. The authors also note that radiation and aging kill the body in similar ways, and suggest that ways of dealing with one may work against the other. An article with a motto in the title Viva la radioresistance! ("Long Live Radiation Resistance!") Was published in Oncotarget magazine.
“The renaissance of astronautics is likely to lead to the first human missions to Mars and deep space. But in order to survive in conditions of increased cosmic radiation, people will have to become more resistant to external factors. In this article, we propose a methodology for achieving increased radioresistance, stress resistance, and aging resistance. In the process of working on the strategy, we brought together leading scientists from Russia, as well as from NASA, the European Space Agency, the Canadian Radiation Center and more than 25 other centers around the world. Radioresistance technologies will also come in handy on Earth, especially if the “side effect” is healthy longevity,”comments Alexander Zhavoronkov, associate professor at Moscow Institute of Physics and Technology.
<img src = "http://old2.naked-science.ru/sites/default/files/images_custom/2018/03/mars7.png" alt = "We will make sure that radiation does not interfere with humanity's conquest of space and colonization Thanks to the scientists, we will fly to the Red Planet and have a disco and barbecue there.
We will make sure that radiation does not interfere with humanity in the conquest of space and the colonization of Mars. Thanks to the scientists, we will fly to the Red Planet and have a disco and barbecue there.
Space versus man
“On a cosmic scale, our planet is just a small ship, well protected from cosmic radiation. The Earth's magnetic field deflects solar and galactic charged particles, thereby significantly reducing the level of radiation on the planet's surface. During long-distance space flights and the colonization of planets with very weak magnetic fields (for example, Mars), there will be no such protection, and astronauts and colonists will be constantly exposed to streams of charged particles with enormous energy. In fact, the cosmic future of mankind depends on how we overcome this problem,”says Andreyan Osipov, head of the Department of Experimental Radiobiology and Radiation Medicine of the A. I. Burnazyan Federal Medical Biophysical Center, Professor of the Russian Academy of Sciences, employee of the Laboratory for the Development of Innovative Medicines at MIPT.
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Humanity has set its sights on colonizing Mars in all seriousness - SpaceX promises to deliver a man to the Red Planet as early as 2024, but some significant problems have not yet been resolved. Thus, one of the main health hazards for astronauts is space radiation. Ionizing radiation damages biological molecules, in particular DNA, which leads to various disorders: the nervous system, the cardiovascular system and, mainly, cancer. Scientists propose to join efforts and, using the latest advances in biotechnology, to increase human radio resistance so that he can conquer the vastness of deep space and colonize other planets.
Human defense
The body has ways to defend against and repair DNA damage. Our DNA is constantly exposed to natural radiation, as well as reactive oxygen species (ROS), which are formed during normal cellular respiration. But when repairing DNA, especially in the case of severe damage, mistakes can occur. The accumulation of DNA damage is considered one of the main causes of aging, so radiation and aging are similar enemies of humanity. However, cells can adapt to radiation. It has been shown that a small dose of radiation can not only not harm, but also prepare cells to meet higher doses. Now international standards for radiation protection do not take this into account. The latest research suggests that there is a certain radiation threshold below which the principle “hard in training - easy in battle” operates. The authors of the article believe that it is necessary to investigate the mechanisms of radio adaptability in order to take them into service.
Alexey Moskalev, Head of the Laboratory of Genetics of Life Expectancy and Aging, Corresponding Member of the Russian Academy of Sciences, Doctor of Biological Sciences, explains: “Our long-term studies of the effects of low doses of ionizing radiation on the lifespan of model animals have shown that small damaging effects can stimulate their own defense systems of cells and the body (DNA repair, heat shock proteins, removal of non-viable cells, innate immunity). However, in space, humans will be faced with a more significant and dangerous range of radiation doses. We have accumulated a large database of geroprotectors. The knowledge gained suggests that many of them function according to the mechanism of activating reserve capabilities, increasing stress resistance. It is likely that such stimulation will help future colonizers of outer space."
Astronaut Engineering
Moreover, among people, radio resistance is different: someone is more resistant to radiation, someone is less. Medical selection of radioresistant individuals involves taking samples of cells from potential candidates and a comprehensive analysis of the radioadaptation of these cells. The most resistant to radiation will fly into space. In addition, genome-wide studies can be carried out on people living in areas with high levels of background radiation or who are exposed to it by profession. Genomic differences in people less susceptible to cancer and other radiation-related diseases can be isolated and "grafted" into astronauts in the future using modern genetic engineering techniques such as genome editing.
There are several options for which genes need to be introduced in order to increase radioresistance. First, antioxidant genes will help protect cells from radiation-induced reactive oxygen species. Several experimental groups have already successfully tried to reduce the sensitivity to radiation using such transgenes. However, this method will not save from direct exposure to radiation, only from the indirect one.
It is possible to introduce genes for proteins responsible for DNA repair. Such experiments have already been carried out - some genes did help, and some led to increased genomic instability, so this area is waiting for new research.
A more promising method is the use of radioprotective transgenes. Many organisms (for example, tardigrades) have a high degree of radioresistance, and if you find out what genes and molecular mechanisms are behind this, they can be transferred to humans using gene therapy. To kill 50% of tardigrades, you need a radiation dose of 1000 higher than the lethal dose for humans. Recently, a protein was discovered that is believed to be one of the factors of such endurance - the so-called damage suppressor Dsup. In an experiment with a human cell line, it was found that the introduction of the Dsup gene reduces damage by 40%. This makes the gene a promising candidate for protecting humans from radiation.
Brawler's first aid kit
Medicines that increase the body's radiation protection are called "radioprotectors." To date, there is only one FDA-approved radioprotector. But the main signaling pathways in cells, which are involved in the processes of senile pathologies, are also involved in responses to radiation. Based on this, geroprotectors - drugs that reduce the rate of aging and prolong life expectancy - can also serve as radioprotectors. According to the Geroprotectors.org and DrugAge databases, there are over 400 potential geroprotectors. The authors believe it will be useful to review existing drugs for hero- and radioprotective properties.
Since ionizing radiation also acts through reactive oxygen species, redox scavengers, or, more simply, antioxidants such as glutathione, NAD and its precursor NMN, can help cope with radiation. The latter, apparently, play an important role in the response to DNA damage, therefore, they are of great interest from the point of view of protection against radiation and aging.
Hypernation in hibernation
Soon after the launch of the first space flights, the leading designer of the Soviet space program, Sergei Korolev, began developing an ambitious project for a manned flight to Mars. His idea was to put the crew in a state of hibernation (English hibernation - "hibernation") during long space travel. During hibernation, all processes in the body slow down. Experiments with animals show that in this state, resistance to extreme factors increases: a drop in temperature, lethal doses of radiation, overload, and so on. In the USSR, the Mars project was closed after the death of Sergei Korolev. And currently the European Space Agency is working on the Aurora project on flights to Mars and the Moon, which is considering the option of hibernation of astronauts. ESA believes that hibernation will provide greater safety during extended automated flight. If we talk about the future colonization of space, then it is easier to transport and protect from radiation a bank of cryopreserved germ cells, and not a population of "ready" people. But this will clearly not be in the near future, and, perhaps, by that time, the methods of radio protection will be developed enough so that a person is not afraid of space.
Heavy artillery
All organic compounds contain carbon-hydrogen bonds (CH). However, it is possible to synthesize compounds that contain deuterium instead of hydrogen, a heavier analogue of hydrogen. Because of the greater mass, bonds with deuterium are more difficult to break. However, the body is designed to work with hydrogen, so if too much hydrogen is replaced with deuterium, it can lead to bad consequences. It has been shown in various organisms that the addition of deuterated water increases lifespan and has anti-cancer effects, but more than 20% of deuterated water in the diet becomes toxic. The authors of the article believe that preclinical trials should be carried out and a safety threshold should be sought.
An interesting alternative seems to be replacing not hydrogen, but carbon with a heavier analogue. 13C is heavier 12C is only 8%, while deuterium is 100% heavier than hydrogen - such changes will be less critical for the body. However, this method will not protect against breaking the N-H and O-H bonds that hold the DNA bases together. In addition, production 13C is very expensive today. Nevertheless, if it is possible to reduce the cost of production, then replacing carbon can provide additional protection for humans from cosmic radiation.
“The problem of radiation safety of participants in space missions belongs to the class of very complex problems that cannot be solved within the framework of one scientific center or even an entire country. It is for this reason that we decided to unite specialists from leading centers in Russia and around the world in order to find out and consolidate their vision of ways to solve this problem. In particular, among the Russian authors of the article there are scientists from the M. V. AI Burnazyan, IBMP RAS, MIPT and other world-famous institutions. During the work on the project, many of its participants first got to know each other and now plan to continue the joint research they have begun,”concludes project coordinator Ivan Ozerov, radiobiologist, head of the cell signaling pathway analysis group at the Skolkovo startup Insiliko.
Designer Elena Khavina, MIPT Press Service