An in vitro blood-brain barrier model for high throughput (HTS) toxicological screening

There is a growing interest to use in vitro BBB cell assays in early safety assessment of compounds. By modifying a well-validated co-culture model of brain capillary endothelial and glial cells, developed by Dehouck et al. [Dehouck, M.P., Meresse, S., Delorme, P., Fruchart, J.C., Cecchelli, R., 1990. An easier, reproducible, and mass-production method to study the blood-brain barrier in vitro. Journal of Neurochemistry 54 (5), 1798-1801], it has been possible to develop a new in vitro BBB system suitable for high throughput screening (HTS). In addition, this new procedure substantially reduces the use of experimental animals and considerably facilitates the process of obtaining a functional in vitro BBB model. The model is ready to use after only 4 days of culture and then shows the typical expression and localization of tight junction proteins. The function of the P-glycoprotein and the transcriptional expression of other efflux transporters such as MRP 1, 4 and 5 have been demonstrated. In addition, the model produces a good in vitro/in vivo correlation for 10 compounds (R2=0.81). Furthermore, studies were undertaken within the European ACuteTox consortium with the objective to assess BBB toxicity and make risk assessments of potentially toxic compounds according to their predicted ability to reach the CNS compartment. These investigations demonstrated that the results produced in the HTS BBB model were similar to the standard co-culture model.

Evidence of lowest brain penetration of an antiemetic drug, metopimazine, compared to domperidone, metoclopramide and chlorpromazine, using an in vitro model of the blood–brain barrier

PURPOSE

The objective of the current study was to determine the ability of some antiemetic compounds to cross the blood-brain barrier (BBB) and thereby to determine possible side effects of compounds for the central nervous system (CNS).

METHODS

We compared the brain penetration of some antiemetic compounds using an in vitro BBB model consisting in brain capillary endothelial cells co-cultured with primary rat glial cells.

RESULTS

This study clearly demonstrated that the metopimazine metabolite, metopimazine acid, has a very low brain penetration, lower than metopimazine and even less than the other antiemetic compounds tested in this study.

CONCLUSIONS

The poor brain penetration of metopimazine acid, metopimazine biodisponible form, seems very likely related to the clinically observed difference in therapeutic and safety profile.