As the prospect of long-duration missions to the International Space Station (ISS) and future flights to Mars becomes more imminent, the need to comprehend and counteract the physiological stresses of space travel has become increasingly pressing.
The unique environment of microgravity and cosmic radiation can accelerate ageing-like processes, causing damage to human tissues and underscoring the importance of targeted research.
A key characteristic of ageing is cellular senescence, which is marked by a stable and irreversible cessation of cell division. Although senescence is necessary for maintaining tissue homeostasis, the progressive accumulation of senescent cells is strongly linked to ageing and the development of age-associated disorders. Senescent cells exhibit the senescence-associated secretory phenotype, a pro-inflammatory mixture of cytokines, chemokines, growth factors, and matrix-remodelling enzymes that, when sustained, drives chronic inflammation and disrupts tissue homeostasis.
While the relationship between senescence and ageing on Earth is relatively well understood, spaceflight introduces a rare combination of environmental pressures that may intensify or alter senescent pathways. In addition to microgravity, astronauts are exposed to ionising cosmic radiation that cannot be completely mitigated by spacecraft shielding. Extensive research has examined the impact of space environments on broader ageing processes, revealing that astronauts exhibit conditions typically associated with advanced age, including increased cancer risk, cataracts, accelerated bone demineralisation, muscle wasting, impaired innate and adaptive immunity, and cardiovascular dysfunction.
Although direct investigations into space-induced changes in senescence are still limited, the connection between senescence and organismal ageing underscores the need for targeted studies to clarify the mechanistic impact of space environments on long-term human health. As plans for future long-duration missions to Mars and beyond are developed, it is essential to continue researching the effects of space travel on the human body to ensure the health and well-being of astronauts on these missions.
The research group led by Dr Sofia Ferreira Gonzalez, Institute for Regeneration and Repair, University of Edinburgh, is currently investigating the topic "Beyond the lab and into space: implications of spaceflight for cellular senescence". This study aims to address the existing knowledge gap by analysing transcriptomic data from astronauts, which is available on NASA's Open Space Data Repository platform. By examining this data, the group seeks to gain a deeper understanding of the effects of spaceflight on cellular senescence, a key aspect of ageing and age-related diseases.
Based on the analysis of hair-follicle samples from NASA astronauts a set of genes that exhibit significant changes in expression between pre-flight and in-flight conditions has been identified. By integrating senescence-related and skin-specific datasets, the key genes involved in both cellular senescence and spaceflight-induced changes in skin physiology were selected, which are likely to play a crucial role in the cellular response to spaceflight and may have implications for our understanding of senescence and skin health in astronauts.
These findings provide new insights into the effects of space travel on the human body and highlight the importance of further research into the molecular mechanisms underlying spaceflight-induced senescence. The identification of these key genes may also have potential applications in the development of countermeasures to mitigate the effects of space travel on skin health and potentially other tissues.
This research serves as the foundation for an extensive, long-term investigation into the role of senescence markers in spaceflight-like environments. Future studies can build upon this work by utilising microgravity models and gamma radiation sources to further probe the effects on senescence-related gene expression. Moreover, employing functional validation techniques, such as gene knockdowns, in conjunction with high-resolution imaging, can provide a more nuanced understanding of the complex signalling pathways involved in senescence.
