SCK•CEN is working on a method for more quickly and accurately determining the radiation dose that a person has received. “This method will be useful in situations involving high exposure to radiation where there is no analysis equipment on site,” according to radiobiologist Sarah Baatout (SCK•CEN). We are unveiling this research today, the International Day of Human Space Flight.
Some genes react more sensitively to ionising radiation. “This means that they contain a lot of information and can tell us more about the amount of radiation our body has absorbed,” says radiobiologist Sarah Baatout (SCK•CEN). The researchers at SCK•CEN recently compiled a list of radiosensitive genes, with a particular focus on exons – the so-called encoding part of a gene. This breakdown is unique in the research field. Sarah: “We tested whether these exons can act as biomarkers in order to measure the radiation exposure.”
There are currently various options for determining the radiation dose a person has received: investigating gene expression, checking chromosomes for abnormalities or measuring DNA damage and recovery from this. “Our DNA contains roughly 50,000 genes. Gene expression gives cells the signal to create proteins when this is necessary. Gene expression gives a general value to each gene, but each exon may react differently to radiation. We can thus obtain more valuable information from this and increase the sensitivity of our measurements. This is why we do not analyse the entire gene, but merely concentrate on those parts that are of interest. By studying the expression of the predetermined exons, we can take accurate measurements shortly after the exposure of the dose received as a function of time. This allows us to speed up response times in the event of nuclear accidents, for example. Fast screening, correct diagnosis and tailored medical treatment increase the chance of survival following high radiation exposure,” according to Roel Quintens, radiobiologist at SCK•CEN. Sarah Baatout adds: “The best solution, though, is to combine total gene expression with exon-specific gene expression.”
Other traditional techniques involve staining chromosomes or locating and repairing the DNA damage. “These techniques are good indicators, but are less sensitive and take a lot of time. Chromosomes, for example, are only visible once the cell begins to divide. After taking a blood sample, the researchers therefore need to isolate and incubate the white blood cells until the chromosomes are visible. After this, they need to stain the chromosomes and/or the DNA damage. This ultimately provides hundreds of cells per patient to analyse, which needs to be done under a microscope,” says Sarah Baatout.
Mission to Mars
The method is currently still in its infancy. “This is the first time that we have attempted to determine radiation exposure in this way as a function of time as well as dose. We identified the radiosensitive genes and listed them as potential biomarkers. Although the first results are promising, the method needs to be refined and adapted through further research,” says researcher Ellina Macaeva, who was involved in this study. However, the team already has big dreams. Sarah Baatout: “We can see this being applied in the field of space travel. Cosmic radiation is one of the biggest obstacles standing in the way of long-term, manned space flight. Astronauts might be exposed to high radiation levels on their mission to Mars. These high radiation levels are due to solar flares and the particles that are released when the Sun is active (solar particle events). Using this method, we would be able to carry out on-board monitoring of the radiation exposure in the body of each astronaut in connection with their specific radiosensitivity.”
Space Summer School
For many years, the Belgian Nuclear Research Centre (SCK•CEN) has played an important role in space research in the areas of radiation dosimetry, human biology and microbiology. “At the end of 2017, I spent a month in Antarctica and we sent the first bioreactor into space,” says Sarah Baatout. "In addition, we organize every year a space summer school. This year, it promises to be an interesting programme filled with interactive theoretical classes, practical exercises and technical visits. You can register until May 20, 2019."
This study was carried out in partnership with Ghent University and the University of Antwerp, and recently appeared in the International Journal of Radiation Biology. It was funded by the European Union’s DoReMi Network of Excellence under grant agreement no. 249689.