IVIVC Assessment of Two Mouse Brain Endothelial Cell Models for Drug Screening

Area of Science:

• Neuroscience
• Pharmacology
• Cell Biology

Background:

• Preclinical drug permeability across the blood-brain barrier (BBB) often relies on rodent models.
• Existing in vitro models like b.End3 cell lines and PAMPA assays have limitations in predicting BBB drug penetration.
• There is a need for reliable in vitro models that mimic BBB characteristics for efficient drug screening.

Purpose of the Study:

• To compare the efficacy of a mouse primary endothelial cell model against b.End3 and PAMPA-BBB models for drug permeability assessment.
• To evaluate the in vitro-in vivo correlation (IVIVC) of these models using known drug BBB penetration data.
• To identify a superior in vitro model for predicting drug permeability across the BBB.

Main Methods:

• Comparison of mRNA expression of key membrane proteins in primary and b.End3 mouse brain endothelial cells.
• Characterization of Transwell® monolayer models for tightness and integrity.
• Calculation of IVIVC by correlating in vitro permeability data with in vivo log BB values for seven drugs.

Main Results:

• The mouse primary model demonstrated superior monolayer integrity and higher mRNA expression of BBB tight junction proteins and membrane transporters, including P-glycoprotein.
• The primary model achieved a high IVIVC (r² = 0.765), significantly outperforming PAMPA-BBB (r² = 0.391) and bEnd.3 (r² = 0.019) models.
• Drug ranking based on permeability predictions strongly favored the primary mouse model.

Conclusions:

• The mouse primary endothelial cell monolayer model is a simple, reliable, and accurate tool for predicting drug permeability across the BBB.
• This model effectively reproduces key BBB tissue characteristics and offers a rapid setup for drug screening.
• The findings support the use of this primary model as a preferred alternative to rodent studies and less predictive in vitro assays.