Quantitative Evaluation of Respiration Induced Metabolic Oscillations in Erythrocytes

Bjørn Hald , Mads F. Madsen , Sune Danø , Bjørn Quistorff , Preben G. Sørensen

The changes in the partial pressures of oxygen and carbon dioxide (P and P) during blood circulation alter erythrocyte metabolism, hereby causing flux changes between oxygenated and deoxygenated blood. In the study we have modeled this effect by extending the comprehensive kinetic model by Mulquiney and Kuchel (1999) with a kinetic model of hemoglobin oxy/deoxygenation transition based on an oxygen dissociation model developed by Dash and Bassingtwaighte (2004). The system has been studied during transitions from the arterial to the venous phases by simply forcing P and P to follow the physiological values of venous and arterial blood. The investigations show that the system passively follows a limit cycle driven by the forced oscillations of P and is thus inadequately described solely by steady state consideration. The metabolic system exhibits a broad distribution of time scales. Relaxations of modes with hemoglobin and Mg binding reactions are very fast, while modes involving glycolytic, membrane transport and 2,3-BPG shunt reactions are much slower. Incomplete slow mode relaxations during the 60 s period of the forced transitions cause significant overshoots of important fluxes and metabolite concentrations – notably ATP, 2,3-BPG, and Mg. The overshoot phenomenon arises in consequence of a periodical forcing and is likely to be widespread in nature – warranting a special consideration for relevant systems.

Mots clés: Erythrocytes; Blood Circulation; Mathematical Modelling; Oscillations

Bjørn Hald, Mads F. Madsen, Sune Danø, Bjørn Quistorff, Preben G. Sørensen. Quantitative Evaluation of Respiration Induced Metabolic Oscillations in Erythrocytes. Biophysical Chemistry, 2009, 141 (1), pp.41. ⟨10.1016/j.bpc.2008.12.008⟩. ⟨hal-00531138⟩