Gravity influences physical and biological processes, especially during development and homeostasis of several tissues in the human body. Studies under altered gravity have been receiving great attention toward a better understanding of microgravity-, hypogravity (<1 g)-, or hypergravity (>1 g)-induced alterations. In this work, the influence of simulated hypergravity over human tendon-derived cells (hTDCs) was studied at 5, 10, 15, and 20 g for 4 or 16 h, using a large diameter centrifuge. Main results showed that 16 h of simulated hypergravity limited cell proliferation. Cell area was higher in hTDCs cultured at 5, 10, and 15 g for 16 h, in comparison to 1 g control. Actin filaments were more pronounced in hTDCs cultured at 5 and 10 g for 16 h. Focal adhesion kinase (FAK) was mainly expressed in focal adhesion sites upon hypergravity stimulation, in comparison to perinuclear localization in control cells after 16 h; and FAK number/cell increased with increasing g-levels. A tendency toward an upregulation of tenogenic markers was observed; scleraxis (SCX), tenascin C (TNC), collagen type III (COL3A1), and decorin (DCN) were significantly upregulated in hTDCs cultured at 15 g and COL3A1 and DCN were significantly upregulated in hTDCs cultured at 20 g. Overall, simulated hypergravity affected the behavior of hTDCs, with more pronounced effects in the long-term period (16 h) of stimulation.
Costa-Almeida, R., Carvalho, D. T. O., Ferreira, M. J. S., Pesqueira, T., Monici, M., van Loon, J. J. W. A., ... Gomes, M. E. (2018). Continuous exposure to simulated hypergravity-induced changes in proliferation, morphology, and gene expression of human tendon cells. Stem Cells and Development, 27(12), 858-869. https://doi.org/10.1089/scd.2017.0206