Biocompatibility and immune response to biomaterials

The host response is an inevitable and unavoidable consequence of any tissue engineering or regenerative medicine strategy for organ restoration. Logically, the manner in which the host responds to the selected intervention will be a critical determinant of the survival and downstream functionality of the engineered organ. Depending on the source of the cells and the type of material chosen, this response may include components of the innate and adaptive arms of the immune system. A number of well-known host responses including transplant rejection, the host response to tissue injury, and the foreign body reaction are described as a basis from which to understand the host response to engineered organs, which may encompass multiple aspects of each of these responses. A focus upon the role of the innate immune system and macrophages in particular is provided and new paradigms surrounding the host macrophage response are discussed.