A Possible Cardiovascular Predictor of Susceptibility to Microgravity
Alamelu Sundaresan
Knowledge of the expression levels of key molecules in low gravity and high stress environments such as microgravity, high altitude and other specialized aviation exercises is essential for the development of intervention strategies and prevention of catastrophic aviation events to ensure mission success. The careful study of adaptational responses in both human and closely related mammalian systems will help identify targets and propose interventions for successful aviation and space exploration Gene expression analysis of normal donor lymphocytes in microgravity analog cultures was performed and it was found that PIGf (Placental induced growth factor), a member of the vascular endothelial growth factor (VEGF) family, a group of potent inducers of angiogenesis with the ability to activate both endothelial cell proliferation and migration, was up-regulated by more than five fold indicating deregulation of cardiovascular signaling pathways indicated by up-regulation of PIGf. PIGf is now clinically considered a more specific biomarker than C-reactive protein for predicting stroke and heart attacks. This was followed by reverse transcriptase Polymerase Chain Reaction (rt-PCR) and Enzyme Linked Immunosorbent Assay (EL- ISA) analysis to corroborate findings. Both methods indicate that up-regulation of PIGf is consistent at the DNA, RNA and protein levels including the “in vivo” microgravity analog model. (p<0.001) and this study will be expanded to cardiovascular compromised patients in the VA hospital and normal test subjects at the NASA Johnson Space Center.
Keywords: Placental growth factor, microgravity, acute coronary syndrome, inflammation, in vitro studies, physiological stress