Region-specific blood-brain barrier transporter changes leads to increased sensitivity to amisulpride in Alzheimer’s disease

Research into amisulpride use in Alzheimer’s disease (AD) implicates blood-brain barrier (BBB) dysfunction in antipsychotic sensitivity. Solute carrier function in AD has not been widely studied. This study tests the hypothesis that organic cation transporters contribute to the BBB delivery of antipsychotics and is disrupted in AD. I n vitro BBB studies indicated that [3H]amisulpride and [3H]haloperidol were transported by OCT1. Amisulpride also utilized PMAT. Molecular docking predicted that amisulpride and haloperidol are OCT1, PMAT and MATE1 substrates, and amisulpride is not a P-gp substrate. Amisulpride brain uptake increased in 3xTgAD compared to wildtype mice. PMAT and MATE1 expression was reduced in brain from AD patients compared to controls. The increased sensitivity of Alzheimer’s patients to amisulpride is related to previously unreported changes in OCT1, PMAT and MATE1 function/expression at the BBB. Dose adjustments may be required for drugs that are substrates of these transporters when prescribing for AD patients. * (OCT) : organic cation transporters (OCTN) : organic cation transporters novel (hCMEC/D3) : immortalized human cerebral microvessel endothelial cell line (MATEs) : multi-drug and toxic compound extrusion proteins (PMAT) : plasma membrane monoamine transporter, 3xTgAD (FBS) : foetal bovine serum (BBB) : blood-brain barrier (AD) : Alzheimer’s disease (P-gp) : P-glycoprotein (BCRP) : breast cancer resistance protein (MRP) : multi-drug resistance protein.