Allometric scaling in-vitro.
About two decades ago, West and coworkers established a model which predicts that metabolic rate follows a three quarter power relationship with the mass of an organism, based on the premise that tissues are supplied nutrients through a fractal distribution network. Quarter power scaling is widely considered a universal law of biology and it is generally accepted that were in-vitro cultures to obey allometric metabolic scaling, they would have more predictive potential and could, for instance, provide a viable substitute for animals in research. This paper outlines a theoretical and computational framework for establishing quarter power scaling in three-dimensional spherical constructs in-vitro, starting where fractal distribution ends. Allometric scaling in non-vascular spherical tissue constructs was assessed using models of Michaelis Menten oxygen consumption and diffusion. The models demonstrate that physiological scaling is maintained when about 5 to 60% of the construct is exposed to oxygen concentrations less than the Michaelis Menten constant, with a significant concentration gradient in the sphere. The results have important implications for the design of downscaled in-vitro systems with physiological relevance.
Department of Information Engineering and Research Center E.Piaggio, University of Pisa, Pisa, Italy.
Arti
A
Ahluwalia
D000818:Animals; D002452:Cell Count; D002478:Cells, Cultured; D004734:Energy Metabolism / Q000502:physiology*; D005057:Eukaryotic Cells / Q000166:cytology / Q000378:metabolism*; D017709:Fractals; D007700:Kinetics; D008954:Models, Biological; D010101:Oxygen Consumption / Q000502:physiology*; D018874:Spheroids, Cellular / Q000166:cytology / Q000378:metabolism*