NASA study examines the effects of microgravity on the immune system

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An oxygen burst released from leukocytes, magnified 20 times (Image: ESA)

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A new study by NASA intends to examine the detrimental effects of microgravity on the immune system, by studying the blood of rats and blue mussels over the course of a prolonged stay aboard the International Space Station (ISS). The experiments, TripleLux A & TripleLux B, will be transported to the station by consecutive SpaceX commercial resupply missions. It is hoped that the results of the study could potentially inform future treatment options for immune system deficiencies both in space and on Earth.

Ordinarily, the human body is protected by a highly-advanced immune system comprised of large cells known as leukocytes that swarm potentially hazardous foreign bodies, producing a bloom of oxygen that makes an invading entity easier to eliminate. However, thanks to previous studies on the immune system in microgravity, we know that an astronaut's immune system is for some reason less effective in space than it is back on Earth. NASA scientists hope to capitalize on this phenomenon, using the unique environment existing aboard the ISS to understand why the system is compromised, and examine how a weakened immune system fights off an infection in a controlled microgravity environment.

In the pursuit of this goal, the agency plans to send two experiments to the ISS, the first of which, TripleLux-B, is slated to launch to the station aboard SpaceX's fifth resupply mission to the station on the 16th of this month. This experiment will study the cellular changes exhibited by blue mussels, an organism with a highly-advanced immune system, whilst the second, TripleLux-B, will examine the protective system of mice. These animals were chosen as test subjects, as both boast relatively similar immune systems that are easy to maintain in microgravity.

In order to ensure the good health of the crew aboard the ISS, the station's sealed atmosphere must be kept free of potentially harmful agents. Therefore, to safely observe how a weakened immune system reacts to a potentially harmful foreign body, the crew will expose the subjects to zymosan, a non-harmful bacteria substitute derived from yeast. The crew will then observe the immune systems at work, using a luminescent chemical to emphasize the tell-tale oxygen bursts that appear as the leukocyte cells neutralize the invader.

TripleLux Advanced Experimental Containment (AEC) hardware (Image: ESA)

"Our goal with TripleLux-B is to find out whether the cells of the immune system of the mussel, which is older in an evolutionary sense, are affected in the same way as those in the immune system of an astronaut – or, in this case, a rat," states Peter-Diedrich Hansen, a professor of toxicology and a senior research scientist at Germany’s Berlin Institute for Technology and Principal Investigator of the project. "And if not, what makes it different?".

It is also hoped that the experiments will be instrumental in shedding light on the effects of microgravity on a cellular level, and how these changes weaken the effectiveness of the immune system. Furthermore, NASA intends to isolate the effects resulting from prolonged exposure to microgravity from those caused by, for example, radiation, with help from the European Space Agency's (ESA) BIOLAB centrifuge, currently installed aboard the ISS.

During this stage of the experiment, specimens will be tested in BIOLAB's 1g centrifuge, simulating the effects of Earth's gravity whilst still exposing the subjects to cosmic radiation. This process will allow scientists to deduce whether the lowered immune system evidenced in astronauts returning from a stint aboard the station, is a result of microgravity, cosmic radiation, or a combination of the two.

It is hoped that the results of this research will lead to new treatment options for those suffering from an impaired immune system living on Earth, and eventually lead to measures that will protect astronauts embarking on long-haul missions to Mars, and beyond.

Source: NASA

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