Freeze-Drying of Decellularized Heart Valves for Off-the-Shelf Availability
Malfunctioning heart valves can cause severe health problems, which if left untreated can lead to death. One of the treatment options is to replace a diseased heart valve with a decellularized valve construct prepared from human or animal material. Decellularized tissue scaffolds closely resemble properties of native tissue, while lacking immunogenic factors of cellular components. After transplantation, circulating stem and progenitor cells of the patient adhere to the scaffold resulting in in vivo tissue regeneration of the valve. Decellularized heart valve scaffold implants need to be stored to be readily available whenever needed, which can be done by freeze-drying. The advantage of freeze-drying is that it does not require bulky and energy-consuming freezing equipment for storage and allows easy transport. This chapter outlines the entire process from decellularization to freeze-drying to obtain dry decellularized heart valves, which after a simple rehydration step, can be used as implants. The protocol is described for porcine heart valves, but procedures can easily be adapted for material obtained from other species.