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Effect of Microgravity on Cartilage Morphology and Biology (Cartilage)
Principal Investigator
Research Area:
Clinical medicine
Species Studied
Scientific Name: Homo sapiens Species: Human

At this time the effects of space flight on the health of joint cartilage in healthy human subjects are not known. It is not determined if the unloading of the lower joints, particularly the knee, causes biological changes in the knee cartilage, or if the current exercise regime is efficient in avoiding long-term effects. The potential of cartilage to restore itself or to repair cartilage defects is very limited and the negative effects might not be obvious in the near future, but might cause arthritis or similar problems in the future for long-term space flight participants.

Articular cartilage in synovial joints serves a variety of functions including providing joint congruency, transferring and distributing forces, and allowing joint movement. Healthy cartilage is the prerequisite for proper joint function, and thus for unconfined physical activity. The effects of immobilization on articular cartilage in humans are barely known and cartilage health of the lower limb joints has not been studied in microgravity. Healthy articular cartilage tends to be thickest in joints that experience high forces such as the knee. These data suggest that cartilage thickness in patients is sensitive to unloading.

While in microgravity, the high impact forces are absent, and this potentially could lead to cartilage degeneration or osteoarthritis. The reported changes include decreases in proteoglycan concentration and compressive stiffness, and cartilage softening. To test the effect of unloading on cartilage thickness and volume, magnet resonance imaging of the astronauts’ knees will be performed before and after a stay in microgravity. Blood and urine samples will be taken before, during (if possible) and after a stay in microgravity to investigate the effect of immobilization on biomarkers of cartilage metabolism (COMP, C2C, CPII, C1,2C, CS-846, CTX-II).

Specific Aims:
1. To investigate the effect of microgravity on cartilage morphology.
a. To investigate the effect of microgravity on cartilage biology.
b. To detect possible correlations between cartilage morphology and muscle atrophy.

2. To understand the effects of space flight on articular cartilage health.
a. To assess the risk of cartilage degeneration during medium and long term space missions.
b. To develop effective countermeasures for cartilage degeneration during medium and long-term space missions.

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Cartilage, articular

Data Information
Data Availability
Archiving in progress. Data is not yet available for this experiment.

Cartilage oligomeric matrix protein
Cartilage thickness
Cartilage volume
Cross Sectional Area - thigh muscle
C-telopeptide fragments of type II collagen
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Mission/Study Information
Mission Launch/Start Date Landing/End Date Duration
Expedition 35 03/15/2013 05/13/2013 58 days
Expedition 36 05/13/2013 09/10/2013 166 days
Expedition 37 09/10/2013 11/10/2013 61 days
Expedition 38 11/10/2013 03/10/2014 120 days
Expedition 40 05/13/2014 09/10/2014 133 days
Expedition 41 09/10/2014 11/09/2014 29 days
Expedition 42 11/10/2014 03/11/2015 121 days
Expedition 43 03/11/2015 06/10/2015 91 days
Expedition 44 06/10/2015 09/11/2015 93 days
Expedition 45 09/11/2015 12/11/2015 91 days
Expedition 46 12/11/2015 03/02/2016 82 days
Expedition 47 03/02/2016 06/18/2016 108 days
Expedition 48 06/18/2016 09/06/2016 80 days
Expedition 49 09/06/2016 10/30/2016 54 days
Expedition 50 10/28/2016 04/09/2017 164 days

Additional Information
Managing NASA Center
Johnson Space Center (JSC)
Responsible NASA Representative
Johnson Space Center LSDA Office
Project Manager: Pamela A. Bieri
Institutional Support
European Space Agency (ESA)