The Case for Bisphosphonate Use in Astronauts Flying Long-Duration Missions.

Area of Science:

• Space biology
• Bone physiology
• Gerontology

Background:

• Bone structure adapts to microgravity in space and to aging, exercise, or disuse on Earth.
• Understanding Earth-based bone remodeling aids in assessing spaceflight-induced skeletal changes and fracture risks for astronauts.
• Astronauts' fitness and exercise regimens differ significantly from age-related bone pathology in the elderly.

Purpose of the Study:

• To identify cellular similarities between spaceflight and age-related bone loss for fracture prediction.
• To examine limitations of terrestrial clinical methods in assessing spaceflight-induced bone microarchitectural changes.
• To detail bisphosphonates as a prophylactic measure against bone resorption during long-duration spaceflights.

Main Methods:

• Comparative analysis of cellular mechanisms in spaceflight-induced bone loss and age-related bone changes.
• Review of current clinical testing for age-related bone conditions and its applicability to astronauts.
• Examination of bisphosphonate drug effects on bone resorption in the context of microgravity.

Main Results:

• Cellular analogies exist between bone loss in space and aging, potentially aiding fracture risk assessment.
• Over-reliance on Earth-based clinical tests may overlook unique spaceflight-induced disruptions in trabecular bone microarchitecture.
• Bisphosphonates can suppress elevated bone resorption, offering a protective countermeasure for astronauts.

Conclusions:

• Bisphosphonates can serve as a prophylactic treatment to protect bone structure during spaceflight, complementing or substituting exercise.
• Further research is needed to refine clinical assessments for astronaut skeletal health, considering unique spaceflight-induced changes.
• Understanding the interplay between microgravity, aging, and bone remodeling is crucial for astronaut long-term skeletal integrity.