Submitting Campus
Daytona Beach
Department
Human Factors and Behavioral Neurobiology
Document Type
Article
Publication/Presentation Date
11-2-2020
Abstract/Description
A comprehensive understanding of spaceflight factors involved in immune dysfunction and the evaluation of biomarkers to assess in-flight astronaut health are essential goals for NASA. An elevated neutrophil-to-lymphocyte ratio (NLR) is a potential biomarker candidate, as leukocyte differentials are altered during spaceflight. In the reduced gravity environment of space, rodents and astronauts displayed elevated NLR and granulocyte-to-lymphocyte ratios (GLR), respectively. To simulate microgravity using two well-established ground-based models, we cultured human whole blood-leukocytes in high-aspect rotating wall vessels (HARV-RWV) and used hindlimb unloaded (HU) mice. Both HARV-RWV simulation of leukocytes and HU-exposed mice showed elevated NLR profiles comparable to spaceflight exposed samples. To assess mechanisms involved, we found the simulated microgravity HARV-RWV model resulted in an imbalance of redox processes and activation of myeloperoxidase-producing inflammatory neutrophils, while antioxidant treatment reversed these effects. In the simulated microgravity HU model, mitochondrial catalase-transgenic mice that have reduced oxidative stress responses showed reduced neutrophil counts, NLR, and a dampened release of selective inflammatory cytokines compared to wildtype HU mice, suggesting simulated microgravity induced oxidative stress responses that triggered inflammation. In brief, both spaceflight and simulated microgravity models caused elevated NLR, indicating this as a potential biomarker for future in-flight immune health monitoring.
Publication Title
Frontiers in Immunology
DOI
https://doi.org/10.3389/fimmu.2020.564950
Publisher
Frontiers in Immunology
Grant or Award Name
NASA’s Space Biology Grant NNX15AB42G
Scholarly Commons Citation
Paul AM, Mhatre SD, Cekanaviciute E, Schreurs A-S, Tahimic CGT, Globus RK, Anand S, Crucian BE and Bhattacharya S (2020) Neutrophil-to-Lymphocyte Ratio: A Biomarker to Monitor the Immune Status of Astronauts. Front. Immunol. 11:564950. doi: 10.3389/fimmu.2020.564950
Included in
Biological Phenomena, Cell Phenomena, and Immunity Commons, Immunity Commons, Molecular and Cellular Neuroscience Commons, Preventive Medicine Commons
Additional Information
Dr. Paul was not affiliated with Embry-Riddle Aeronautical University at the time this paper was published.