Development of a new generation pulsatile bioreactor for in vitro study of tissue-engineered heart valve

Objective:To develop a simple and economical pulsatile bioreactor for in vitro study of tissue-engineered heart valve(TEHV). Methods: The pulsatile bioreactor, taking the shape of a discus, was made from materials innoxious to living cells. The bioreactor was an airtight system consisting of a valve chamber and a power chamber in which a simple ventilator served as the pulsing power. Movements of diaphragm between the valve chamber and the power chamber mimicked the systole and diastole of the ventricles. After implanted with a mixture of endothelial cells and fibroblasts, decellularized porcine valvular conduit was installed in the valve chamber. The pulse bioreactor was started at a low pulse rate, low flow velocity and low pressure, which gradually increased to the level of a normal adult within 48 h. The valvular conduit was subjected to pathological observation 6 days later. Contamination was confirmed when the media in the bioreactor become opacified and/or when microorganism was found at the end of experiment. Results: The pulsatile bioreactor could generate a flow rate of 50-6 000 ml/min, a systolic pressure of 10-120 mmHg (1 mmHg = 0.133 kPa) , a diastolic pressure of 5-70 mmHg, and a pulse rate of (5-80) times/min. The current bioreator significantly decreased the infection rate compared with the first generation bioreactor(100.00% vs 27.27%, P0.01), and its internal evironment and operation were stable. Pathological observation and electron microscopy showed that the implanted valvular conduits was completely re-endothelialized and living fibroblasts could be found. Conclusion: The new genereation pulsatile bioreator, with low contamination rate, is stable, economical, easy to operate and requires no restriction to site. And it is worth recommending. -