Table 4.

Changes in Properties of the BBB as Reported in Health and Under Specific Disease Conditions

Process	AD	ALS	Epilepsy	MS	Stroke	Tumour	PD
Passive transport
(paracellular)	+	+	+	+	+	+	+
Active influx	+	?	?	?	?	+	?
Active efflux	±	+	+	?	–	+	+/

See i.e. (7,23) for some excellent reviews on this topic. It is shown how BBB trancellular transport, paracellular transport, active efflux and active efflux are affected in brain diseases compared to healthy conditions. There, no distinction is made between individual transporter types, but it is shown for active influx and active efflux in general. This is shown for Alzheimer’s Disease (AD) (see i.e. (11,12)). amyotrophic lateral sclerosis (ALS) (see i.e. (13)) epilepsy (15), multiple sclerosis (MS) (16), Parkinson’s Disease (PD) (17–19), stroke (20,21) and tumour (i.e. (22)). A + indicates an increase of the extent of the BBB transport process that is associated with the disease, while a - indicates a decrease. A ± indicates that both increases and decreases have been observed as a consequence of the disease. Finally, a? indicates that disease-induced changes on the BBB transport process are not known