Joint Cartilage in Long-Duration Spaceflight.

Area of Science:

• Space Medicine
• Orthopedics
• Biomedical Engineering

Background:

• Current evidence on joint cartilage alterations in long-duration spaceflight is limited, primarily from astronaut serum biomarkers.
• Analogue models (bed rest, animal, cell studies) suggest unloading and radiation exposure contribute to cartilage degeneration.
• The specific impact on human cartilage regions during missions beyond Low Earth Orbit remains largely unknown.

Purpose of the Study:

• To review existing literature on joint cartilage changes associated with long-duration spaceflight.
• To identify knowledge gaps regarding cartilage and subchondral bone responses to spaceflight stressors.
• To highlight the need for effective countermeasures against cartilage damage and osteoarthritis (OA).

Main Methods:

• Literature review of studies on joint cartilage in spaceflight and analogue models.
• Analysis of data from astronaut serum biomarkers, bed rest studies, and microgravity research.
• Synthesis of findings on cartilage thinning, compositional changes, and degeneration.

Main Results:

• Unloading and radiation exposure are linked to cartilage thinning and altered composition.
• Limited astronaut data exists, necessitating reliance on analogue models.
• The extent of cartilage region-specific damage in humans on extended missions is undetermined.

Conclusions:

• Joint cartilage degeneration is a potential risk of long-duration spaceflight.
• Effective countermeasures are crucial to prevent cartilage damage and future OA in astronauts.
• Further research is required to validate the efficacy of proposed countermeasures for space missions.