Objectives

Our main objective is to establish, using resected and post mortem brain tissue, the neuroanatomical parameters that are essential for the interpretation of the in-vivo imaging data, and to determine the role and mechanisms of transporter-encoding gene variation in these parameters and in the neuroimaging patterns observed.

 

Workpackage description

Immunohistochemistry studies in human brain have shown ectopic expression of the most-widely studied transporter, P-gp, in epileptogenic brain tissue, leading to a general assumption that P-gp quantity, and by implication function, is increased in epileptogenic brain tissue. We will determine the distribution of multidrug transporters in human brain tissue, to generate models that can be taken to in vivo imaging experiments.

In resected material obtained from therapeutic lobectomies, and in post mortem material, we will immunolabel several transporters. All cases for comparison will be prepared and imaged using one system in one laboratory under standardised conditions. We will examine specific cell populations by using double labelling as necessary. Data obtained will constrain and inform interpretation of neuroimaging from other workpackages, particularly for epilepsy surgical resection cases. This will have implications for putative treatment strategies based on evasion or inhibition of transporters

To confirm effects on primary BBB function of transporter quantity and distribution, we will undertake immunohistochemistry for other markers and constituents of barrier integrity. We will provide parallel data on the function of barriers to which transporters contribute.

We will also examine the relationship between genetic variation in transporter-encoding genes and imaging. To complement these analyses and integrate those with the critical findings at a cellular level that will ultimately determine the nature and success of therapies based on transporter function modulation, we will undertake molecular genetic analyses in fresh-frozen human brain tissue from epilepsy, and control brain. Consideration of the molecular genetics of transporters within the microenvironmental patterns of expression within the brain is particularly important given the inducibility of expression that may occur in association with disease.