This study investigated the factors influencing the oxygen metabolism of aortic valve interstitial cells (VICs). Porcine VICs in cell suspension at different passages, and adhered to coverslips at different confluencies, as well as fresh porcine valve leaflets, were incubated in an oxygen respiration chamber at 37 degrees C in Dulbecco's modified Eagle's medium. The consumption rates at different oxygen concentrations were evaluated based on the Michaelis-Menten equation, and the corresponding maximum consumption rate (V(max)) and the Michaelis-Menten equation constant K(m) were determined. In all cases, the oxygen consumption rate was relatively constant until the concentration dropped to 5% (v/v). The metabolic activity of VICs in terms of oxygen consumption was dependent upon their in vitro passage number and proliferation status. These findings will provide valuable input to the selection of VICs with respect to their age and proliferation status for tissue engineering applications, as well as important input parameters for developing computational models of oxygen transport and optimization of the bioreactor conditions for heart valve tissue engineering.