Comment on ‘Dynamic analysis of optimality in myocardial energy metabolism under normal and ischemic conditions’

Mol Syst Biol. 4: 207In a recent paper, Luo et al (2006) present an innovative and perhaps useful approach to simulating metabolism, termed M‐dynamic flux balance analysis, in which metabolic fluxes are estimated by minimizing an objective function that is computed from a weighted sum of deviations in fluxes and concentrations from baseline conditions. Unfortunately, this study is severely deficient in terms of its presentation, model assumptions, and validation of modeling predictions.One problem with the presentation is that key variables are not given units. For example, the flow F is varied from 1 to 0.2 to simulate myocardial ischemia. Although the reader is not told about the units by which flow is measured, it is apparent from the equations that F must have units of inverse time. Thus perhaps F represents flow divided by volume. In that case, for the simulated range to be reasonable, we might guess that the units are 1/min. The following analysis of the method and results of Luo et al (2006) assumes this guess to be correct.In addition to the lack of rigor in its …