Student Poster Presentation #2 (Session 1)
Adipose Derived Stem Cell Reprograming as a Result of Size
Dependent Aggregation
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Brent M. Bijonowski M.Sc., 1 Yijun Liu Ph.D., 2 Ang-Chen Tsai Ph.D., 1 Teng Ma Ph.D. 1
Florida State and Florida Agricultural and Mechanical University College of Engineering, Tallahassee,
FL 32310. 2 City of Hope National Medical Center, Durante, CA 91010
Abstract
With increasing interest in embryonic development an tissue engineering the problem of aggregate oxygen and
carbon consumption and diffusion is of great interest. [1,2] Adipose derived stem cells[ASCs] undergo a metabolic
reprogramming upon aggregation. Aggregates of ASC show a lower oxygen consumption rate than their
monolayer counterparts. [3] We hypothesize that this is a result of stress in response to the aggregation event.
Aggregates were formed in a ultra-low attachment 96 well plate with approximate cell numbers of 5, 10, 30, and
50 thousand cells per aggregate which have diameters ranging from approximately 400 to 700µm. The
aggregates were incubated for four days to allow cells to homogenize throughout the aggregate. The oxygen was
measured via an orgo-metalic Ruthenium complex that was added to the culture media. Images were taken of
the aggregates and were processed in a custom MatLab program. From this information we determined that there
isn’t a hypoxic zone in any of the aggregates and the oxygen consumption rate. The 50,000 cell aggregates had
almost twice the consumption rate that was found in the 5000 cell aggregates. Analysis of the glucose and lactate
showed that 5000 cell aggregates had larger glucose consumption than 50,000 cell. This suggests that the 5000
cell aggregates are undergoing anaerobic glycolysis instead of oxidative respiration. ASCs commonly undergo
vascular niche differentiation in the body, and are highly mechanical sensitive. We investigated the Akt pathway
as a means of this reprogramming. Upon inhibition of phosphorolation of the Akt protein with Wortammin
(40nM) the oxygen consumption rate returned to nearly monolayer levels.
Reference
[1] Murphy, Kaitlin C., Ben P. Hung, Stephen Browne-Bourne, Dejie Zhou, Jessica Yeung, Damian C. Genetos, and J.
Kent Leach. "Measurement of Oxygen Tension within Mesenchymal Stem Cell Spheroids." Journal of The Royal Society
Interface 14.127 (2017):
[2] Van Winkle A, P, Gates I, D, Kallos M, S, Mass Transfer Limitations in Embryoid Bodies during Human Embryonic
Stem Cell Differentiation. Cells Tissues Organs 2012; 196:34-47
[3] Pattappa, Girish, Hannah K. Heywood, De Bruijn Joost D., and David A. Lee. "The Metabolism of Human
Mesenchymal Stem Cells during Proliferation and Differentiation."Journal of Cellular Physiology. Wiley Subscription
Services, Inc., A Wiley Company, 22 July 2011.
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