Chicken embryo as a model for regenerative medicine.

Although the chick embryo, including its extraembryonic membranes, has long been used as a model for developmental biology, its potential as a model for the repair and regeneration of adult human tissues is often overlooked. The chick offers a well-defined profile of intercellular and intracellular signaling pathways regulating the development of nearly every organ system in conjunction with great flexibility for chimeric and transgenic experiments. Depending upon the system of interest, the chick can either directly reflect the human condition, as in spinal cord repair or in chorioallantoic membrane wound healing, and therefore act as an in vivo model for repair, or mirror our aspired therapy as in limb generation or otic restoration and therefore act as our guide. With these unique opportunities, the chick embryo is certainly a model to be considered when aiming to develop a regenerative therapy for human applications.