Immune dysfunction in spaceflight and diabetes mellitus – translating space observations to terrestrial disease

Introduction: Spaceflight alters normal physiology of cells and tissues seen on Earth. Immune cells and signaling molecules appear to be particularly affected, resulting in changes in leukocyte populations, killing ability and effector function, and signaling molecule response. Akin to spaceflight, diabetes mellitus produces significant immune system dysfunction. Applying observations and interventions from spaceflight to conditions such as diabetes mellitus may help to identify new approaches that combat the high clinical and financial burden of terrestrial disease.Discussion: A literature review was conducted using PubMed, MEDLINE, and Google Scholar. Papers of immune cells conducted in space and studies on diabetes mellitus-related immune dysfunction were included. Broad themes of immunosuppression were seen in both spaceflight and diabetes mellitus. Effects on lymphocytes, neutrophils, eosinophils, monocytes, fibroblasts, growth factors, and inflammatory factors are presented.Conclusions: Immune responses to spaceflight and DM are inconsistent. The innate immune system responds similarly to spaceflight and DM. In contrast, the adaptive immune system responds differently to spaceflight than to DM. This difference may be the result of a glucocorticoid dominant response linked to innate suppression and a Th2 lymphocyte shift.Relevance: Diabetes mellitus causes major morbidity and mortality on Earth. Further research is needed to elucidate mechanisms behind these differences and develop countermeasures for immunosuppression in space with application towards diabetic therapy on earth. Furthermore, commercial spaceflight makes it all the more necessary to elucidate these mechanisms as civilian participants with diabetes mellitus or other immune-altering conditions may be space bound.