James A Ankrum

Much of the in vitro study of organs relies on responses from monolayers composed of one or more cell types; however, in many cases, this simplistic modeling of the organ system does not replicate how cells behave in vivo in the context of their organ and organism. While many useful cell characteristics can be deduced from 2D cell cultures, a full understanding of organ systems and biology requires studying cells in the context of their native environment. Traditionally, animal models have fulfilled this role; however, in the past decade, techniques and technologies to grow 3D tissue organoids in culture have been developed as an intermediate or replacement for in vivo studies. In this chapter, we review the genesis of organoid culture systems and provide an in-depth view of several fields that have been significantly impacted by organoid technology. Finally, we summarize emerging applications of organoids in modeling health and disease, treating patients, and discovering novel pharmaceuticals.

Stem cell therapies offer enormous hope for treating many tragic diseases and tissue defects. In particular, mesenchymal stem/multipotent stromal cells (MSCs) are capable of differentiating into multiple types of connective tissues (i.e., bone, cartilage, and even muscle and neuron) and have proangiogeneic and immunomodulatory effects. MSCs have potential utility for treating a variety of diseases and disorders, including graft versus host disease, problems related to organ transplantation, cardiovascular disease, brain and spinal cord injury, lung, liver, and kidney diseases, and skeletal injuries. This chapter summarizes the current status of therapeutic applications of MSCs. It begins by introducing the basics of MSCs and then focuses on their therapeutic potential, including mechanism of action, delivery routes, MSC homing, the current status of clinical trials, and potential challenges and safety issues. Finally, the chapter describes chemical approaches developed in the authors’ laboratory to promote homing and engraftment of systemically infused MSCs within specific tissues.