Using miniature brain implants in rodents for novel drug discovery.

INTRODUCTION: There continues to be a need to create an artificial human blood-brain barrier for pharmacological testing and modeling of diseases. Our group has recently vascularized human brain organoids with human iPSC-derived endothelial cells. Other groups have achieved brain organoid perfusion after vascularization with murine endothelial cells. Areas covered: This review article discusses the remaining hurdles, advantages, and limitations of creating a human organoid blood-brain barrier in rodents for novel drug discovery. Expert opinion: The creation of a human organoid blood-brain barrier in rodents will be feasible with appropriate molecular and cellular cues. An artificial human blood-brain barrier model may be used for pharmacological testing or for the study of the human blood-brain barrier in development or disease. Potential limitations of the model include an inferior competence of the blood-brain organoid barrier, the immunodeficient environment and low reproducibility due to variations in organoid morphology and vascularization. Despite its limitations, an artificial human blood-brain barrier model in rodents will further our understanding of blood-brain barrier pharmacology, and the field is expected to see significant advances in the next years.