The Effects of Microgravity on Human Endothelial Cells in Relation to Deep Vein Thrombosis

Deep vein thrombosis (DVT) is a condition where blood clots form in one or more of the deep veins of the body, causing leg pain and/or swelling, potentially leading to pulmonary embolism and/or stroke. The incidence of DVT among astronauts serving on the International Space Station has been shown to be greater than that of the general population, calling into question the effects of microgravity on human thrombolytic processes. Additionally, microgravity conditions have been shown to cause muscular atrophy and a decrease in muscle strength and mobility. Because collagen composes a large portion of muscle tissue, this study also assessed the effects of microgravity conditions on collagen I fiber alignment, to investigate the cause of the associated muscular deterioration. Lastly, this study assessed the effects of microgravity on cellular viability through live/dead assays. Microgravity was simulated using a rotating wall vessel (RWV), which rotated samples at 25 RPM for a total of 3 days before analysis. It was found that the live to dead ratios of the 1G samples and mG samples were 2.15:1 and 1.24:1 respectively; also of note was the observation of fewer total cells on the mG samples. This indicates decreased cell viability in microgravity conditions. The increase in deviation angle and total number of immature collagen fibers amongst µG samples indicate microgravity induced randomization of Collagen I fiber realignment. Finally, the effect of microgravity conditions on the regulation of PECAM-1 and PPAR-g proteins was found to be inconclusive, as their expression was not clearly indicated in the immunostaining analysis