Adaptive Response: A Scoping Review of Its Implications in Medicine, Space Exploration, and Beyond

Abstract

Objectives: Radiation Adaptive Response (AR) is a biological phenomenon in which exposure to low-dose radiation (LDR) enhances an organism's ability to withstand subsequent higher doses. This scoping review explores AR across multiple disciplines, summarizing evidence, identifying research gaps, and evaluating potential applications in cancer therapy, neurodegenerative disease management, space medicine, and pandemic response.

Methods: A comprehensive review of experimental/clinical studies on AR was conducted, focusing on molecular mechanisms, biological implications, biophysical modeling, and translational applications.

Results: In oncology, AR has shown promise in selectively protecting normal tissues during radiotherapy while sensitizing tumor cells, yet its effects remain cell-type dependent. LDR may manage neurodegenerative diseases by modulating oxidative stress and inflammation. In space medicine, AR-based astronaut selection has been proposed as a novel strategy to mitigate radiation risks during long-term space missions, although empirical validation is lacking. LDR therapy for managing COVID-19 pneumonia has been explored, but ethical concerns and long-term safety risks require further investigation.

Conclusion: Despite AR's potential, its clinical and spaceflight implementation requires mechanistic elucidation, standardized protocols, and rigorous studies. The risks of tumorigenesis, individual variability in AR, and potential immunomodulatory effects must be evaluated before widespread application. Moreover, inconsistent AR appearance complicates its study and clinical use.

Keywords: COVID-19; adaptive response; cancer therapy; low-dose; space.

Graphical Abstract

Figure 1.

Flow Chart of Article Selection for Scoping Review

Figure 2.

Based on the Model Developed by Mortazavi et al, Astronaut Candidates’ Blood Samples are Exposed to Low-Dose (LDR) and High-Dose Radiation (HDR) to Assess Chromosomal or DNA Damage and Measure Adaptive Response (AR). Candidates With the Strongest AR (Least Damage) are Selected. Selected Astronauts Exposed to Galactic Cosmic Rays (GCR) During Missions Enhance Their AR. During Solar Particle Events (SPEs), Those With the Highest AR are Expected to Better Withstand Radiation With Minimal Health Impacts. NASA and Chancellor Have Developed Alternative Models^,, (Adapted From References^,,)