Laboratory in Space: Hot on the Trails of Cartilage Degradation

On November 10, 2014, astronaut Alexander Gerst will return to Earth from the International Space Station (ISS). He is not just anxiously expected by his family, but also by Dr. Anna-Maria Liphardt from the Institute of Biomechanics and Orthopedics at the German Sport University Cologne (German: Institut für Biomechanik und Orthopädie der Deutschen Sporthochschule Köln, DSHS).


Photo: Dr. Anna-Maria Liphardt

Dr. Anna-Maria Liphardt; ©private

Gerst is one of several astronauts, who participate as subjects in a DSHS study on cartilage degradation in space. The study that Dr. Liphardt is conducting in collaboration with Professor Gert-Peter Brüggemann (Director of the Institute) and PD Dr. Anja Niehoff, is among other things expected to deliver insights as to how quickly cartilage is depleted due to immobilization. Later on, arthritis and osteoporosis patients are meant to benefit from these experiments.

How is this project set up, what steps are meant to lead to a successful result and at which point are you now?

Anna-Maria Liphardt
: Space projects are designed for a longer period of time. For one, the international call for bids (International Research Announcement for Research in Space Life Sciences at the International Space Station - ILSRA) of the International Space Life Sciences Working Group (ISLSWG), where scientists can apply for life science experiments with active astronauts only takes place every four to five years. If you are accepted, in Germany you need to apply for support from the national space agency with the German Aerospace Center (German: Deutsches Zentrum für Luft- und Raumfahrt, DLR e.V.). Generally, you subsequently receive funds to conduct the experiment with approximately five to ten astronauts. The exact number also depends on the type of experiment of course. This application process takes several years. Added to this is the fact that only a limited number of astronauts actually fly to the space station each year. At the moment, six astronauts fly into outer space every six months. Every six months, our experiment is being introduced to three astronauts, but it never happens that all of them are going to participate. For our research on articular cartilage, we would like to study between eight and ten astronauts; so far, we were able to examine four astronauts.

Photo: Alexander Gerst takes a blood sample from himself

On other missions, astronaut Alexander Gerst had to take up to 23 blood samples; © ESA/NASA

What are you researching with subjects that agree to participate in the experiment?

: We take blood and urine samples before and after a 6-month stay at the International Space Station ISS. These samples contain biomarkers that reflect cartilage synthesis and cartilage degradation. Even though this is always an image of the body as a whole and you cannot say whether its cartilage in the knees or ankles that is being affected, you still receive information on what stage the cartilage is in: is everything in balance or is there more of a cartilage buildup or degradation? This type of biomarker originates in the clinical field and is used for patients suffering from rheumatoid arthritis or osteoporosis for example. We use them to see how immobilization changes marker concentration. In addition, we utilize magnetic resonance imaging to measure cartilage thickness and volume in the knee joint. Aside from the hip, the knee is the joint that is most susceptible to arthritis. The space model is ideal for us, because it is best suited to reflect no strain in the lower extremity.

Do exams take place during the flight?

: This is a possibility for blood and urine samples, but we are currently not doing this, since there was no refrigerated return transport for the samples when we started the study. Even though this is now possible again, an early start to our experiments was more important to us.

Can you compare a healthy joint with a damaged one despite immobilization?

: There are differences of course, because a damaged joint hurts and makes patients assume a protective posture, which promotes muscle atrophy for example. As it were, in the case of a damaged joint there is always a combination of possible influencing factors such as pain, an injury, an infection and strain relief by using crutches for instance. To be able to understand what happens to the cartilage, you would actually need to separate the effects of immobilization and the disease. However, this cannot be done, since you would have to immobilize a healthy person here on Earth for a very long time. This is why space provides us with the best conditions for our research: no pressure on the knee joints in extremely physically fit and healthy test subjects.
Photo: Alexander Gerst in space

Alexander Gerst looks through a window in the cupola; ©ESA

Do all astronauts suffer from cartilage degradation after their trip into outer space?

: In the case of astronauts, we currently don’t know how articular cartilage reacts in a micro-g environment. We don’t know whether astronauts later on are more likely to suffer from problems with arthritis or not. We don’t have enough data yet to make that determination. On the one hand, the reasons for this are that MRI devices have only recently exhibited the necessary technical characteristics to provide such high resolution of cartilage in the joint. On the other hand, in the old days, astronauts never used to be this long in space and with such regularity as they are today. In the past, they only spent days or weeks in space, while they spend months there today. The flight length also changes the body’s adjustment to its environment. This is why you can only take a conditional look at past astronauts and say that arthritis results from a previous stay in space.

Once you have gathered all the findings, what is your next step?

: We will analyze the data to be able to transfer them to patients here on Earth. Unfortunately, it will still take some time before our data can be incorporated into an applicable therapy that supports patients with physiotherapy for example.
Photo: Simone Ernst; Copyright: B. Frommann

©B. Frommann

The interview was conducted by Simone Ernst and translated by Elena O'Meara.