Question to the Home Office:

To ask His Majesty's Government, with regard to the project 'Molecular architecture, function and dysfunction of the blood brain barrier' in Animals (Scientific Procedures) Act 1986: Non-technical summaries for project licences granted April – June 2025, published on 11 July, why a licence was granted for that project when human cell-based models of the blood brain barrier are available; and what assessment they have made of how the licence complies with the section 2A of that Act that requires scientifically satisfactory non-animal methods to be used where possible.

The Home Office ensures all licences are fully compliant with all sections of the Animals (Scientific Procedures) Act 1986. In this specific licence, the blood brain barrier is a complex and dynamic multicellular structure. In vitro (non-animal) models cannot fully replicate the interactions in this environment that are possible in a living organism. The project also looks at dysfunction which is difficult to simulate in vitro, especially when looking at certain diseases. Whilst cell-based models exist and are becoming more advanced they are not, in this case, an acceptable model and so would not be a viable alternative. The project will explore the use of brain cells, induced pluripotent stem cells and organoids during the study which will contribute to the potential 3Rs benefits (Replacement, Reduction and Refinement) in this field.